Monograph of the Palaeontographical Society

PALAONTOGRAPHICAL SOCIETY.

BRITISH
CARBONIFEROUS BRACHIOPODA.

Parr V.—Fovurts Portion.

BRITISH FOSSIL REPTILIA

FROM

THE OOLITIC FORMATIONS.

Part First.

SCELIDOSAURUS HARRISONII AND
PLIOSAURUS GRANDIS.

THE EOCENE MOLLUSGCA. |

Part I.
BiPyvA LV Es:

1861.

IssUED FOR THE YEAR 1859.

PALMONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVIL.

LONDON:

MDCCCLXI.

Digitized by the Internet Archive
in 2011 with funding from
California Academy of Sciences Library

http://www.archive.org/details/monographof131861 pala

A MONOGRAPH

B Rel -t I Seer

CARBONIFEROUS BRACHIOPODA.

BY

THOMAS DAVIDSON, F.R.S., F.G.S.,

ETC.

PART V.

FOURTH PORTION.

LONDON:
PRINTED FOR THE PALZONTOGRAPHICAL SOCIETY.
1861.

LULL AO eae Ace
. peers a

t

STROPHOMENA. 121

denotes that a pedicle muscle must have existed, although the foramen became closed as
soon as the animal found it could dispense with the moorings required during the early
stages of its development.’

In the interior of the dorsal valve the cardinal process is divided into two lobes, and
not connate with the diverging socket-ridges. From the base of this a slight median ridge
runs down and separates the two pairs of adductor or occlusor scars, which are bordered
by prominent ridges. The vascular impressions consist of large primary vessels which
run at once direct from near the centre of the valve, to a short distance of the frontal
margin, when they become reflected on either side to surround the ovarian spaces, and,
near the margin, some of the vessels bifurcate several times.

Dimensions very variable: a large example measured, length 17, breadth 32 lines.

Obs. As-may be observed from the synonyms and references given (and which
could have been considerably increased in number), this species has already been located
in at least six genera, and has received twelve or more specific denominations. It is not,
however, surprising that before the class had been sufficiently investigated, and while
efforts where being made to value and define the different interior characters, as a means
of classification, that geologists and paleontologists should have felt uncertain where to
locate this and other species, so that the different generic denominations may thus be easily
and naturally accounted for. We next come to the specific denominations; and here we
open out a field susceptible of much divergence in opinion, for the preconceived opinions of
some paleontologists and geologists make them averse to recognise the existence of the same
species in so extensive a vertical range asthe Si/urian, Devonian, and Carboniferous periods ;
and although the greater number of paleontologists have admitted, in their various works,
that it was scarcely possible to separate the specimens of the shell as found in the three
great divisions of the Palaeozoic period, they still preferred to retain for each a distinct specific
denomination: and this will explain the principal cause of the many names the shell we are
now describing has received at different periods and from different hands.

In 1836, while describing the Carboniferous shell, Professor Phillips observes :—
“T cannot distinguish this from the Dudley species, Z. depressa ;” and the same author
begins the description of his Prod. analoga by stating that, “‘ Perhaps this is really differ-
ent from the last (Z. depressa), but it is difficult to fix on characters.” In 1843, Professor
de Koninck observed, that it was impossible to distinguish the Silurian Sfroph. rhomboidalis
from the Carboniferous Lept. analoga, and he united the two under a single denomination.
In p. 389 of his ‘ British Paleozoic Fossils,’ while alluding to Lept. analoga, Professor
M‘Coy remarks, that “ the shell in the Middle and Upper Paleozoic rocks can scarcely
be considered as a distinct species from LZ. depressa of the Lower Paleozoic strata, and of
which it is only a variety, not separable when the extremes are compared, but generally

' According to Darwin, a muscle does not exist simply because it was created, but because a necessity
for it existed originally, and having once come to be of general use, traces of it might remain (as a rudi-
mentary organ) in after-times, when the creatures had ceased to use it.

16

122 BRITISH CARBONIFEROUS BRACHIOPODA.

recognisable as a distinct variety much in the same way as the Devonian variety aspera,
of the Silurian Spirigerina reticularis, is usually distinguishable from the older varieties.
The general characters of the species are exactly those of Zept. depressa, and the
description given in the Lower Paleozoic section of this species will suit the present one in
nearly all respects. ‘The differences which strike an observer are, that the transverse
wrinkles in the Lower Paleeozoic Z. depressa are usually from twelve to fifteen im number,
but in this variety they are from fifteen to twenty, and the longitudinal striz are, on an
average, considerably coarser m JZ. analoga than in L. depressa.” The last two
observations are not, however, of much importance; for I possess examples of the Silurian
and Devonian shell with as many wrinkles as may be counted upon the generality of
Carboniferous specimens, nor does there exist that great difference in the quality of the
longitudinal strize. Professor M‘Coy then goes on to observe, that as to the varieties
named Lept. distorta by Sowerby (Carboniferous), and Lept. nodulosa by Phillips (Devonian),
he has in the mountain limestone traced all the intermediate varieties to the more regular
types, and no doubt exists in his mind as to their specific identity. It is therefore
evident that, in external shape and character, it is hardly possible to distinguish the
Silurian, Devonian, and Carboniferous shell, and that those little differences that are
occasionally observable, such as number of wrinkles and coarseness of longitudinal striz,
may be due to local conditions which often slightly modify the size and appearance of the
same species.

Now let us cast a glance at the interior of the Silurian and Carboniferous shell.
In the interior of the valves no very important’ differences can be traced, and the only
peculiarity I can perceive is, that the ridges margining the muscular scars are generally
more elevated or produced (though not always so) in the Carboniferous specimens ; and it
appears to me, therefore, that by retaining the term aza/oga as a vanetal designation
for the Carboniferous form, we shall be following the views advocated by the greater
number of palzeontologists.

The variety distorta, which has prevailed in certain localities, can be viewed in no
other light but as that of a malformation, in which the dorsal valve is generally more or less
convex, and bending more or less rapidly inwards before becoming again inflected to
follow closely the deflected prolongation of the ventral valve.

Loc. In England, the Carboniferous variety is common in the Lower Carboniferous
limestone of Longnor, as well as in other Derbyshire localities: it has been collected
at Bolland and the Craven and Wensleydale districts, in Yorkshire ; in Carboniferous shales
at Redesdale, Northumberland; also in the Middle Carboniferous limestone of Ronalds-
way and Poolwash, Isle of Man.

In Scotland, it is found at Gare, in Lanarkshire, in limestone, at 239 fathoms below
the ‘“ Ell Coal,” and 343 at Waygateshaw; in Renfrewshire, near Thornliebank ; in
Stirlingshire, in the Campsie Main limestone and Corrie Burn beds.

Tn Ireland, it appears to occur in all the Lower Carboniferous strata, as well as in the

ow)

STROPHOMENA. 12

Mountain limestone division. It is not rare in the Carboniferous slate, in the parish of
Ballyseedy, county Kerry. Mr. Kelly mentions Ring, Currens, Millecent, and Ballina
county, among the Irish localities ; the variety ‘ disforta”’ being very abundant, especially
in the county of Kildare.

It is also a common species in the Carboniferous rocks of many foreign countries, very
large and fine examples occurring at Visé and Tournay, in Belgium.

The Silurian and Devonian localities will be mentioned in the monographs treating
of the form belonging to those epochs.

Sub-Genus—StREPToRUYNCHUS, King. 1850.

The shells composing this sub-genus are closely related to Strophomena; they are
usually semicircular-convex or concavo-convex, externally striated and interstriated; the
ventral valve possessing a prolonged and oftentimes bent or twisted beak. (See Part IV,
p. 29, of the present volume.)

Many are the so-termed species that have been described as occurring in the Carbo-
niferous rocks of this and other countries, but so exceedingly variable are these shells, and
so intimately do they all appear connected and linked together by intermediate and insen-
sible graduations of shape, that it becomes most puzzling and difficult to determine how
far we may be permitted to lint the extent of variation, or to determine what shapes
ought to be separated or combined under a single species. Darwin considers “the term
species as one arbitrarily given for the sake of convenience to a set of individuals closely
resembling each other, and it does not essentially differ from the term variety, which is
given to less distinct and more fluctuating forms ; that the term variety again, in comparison
with mere differential differences, is also applied arbitrarily and for mere convenience
sake.” And further on the same authorobserves, that ‘no one can draw any clear dis-
tinction between individual differences and slight varieties, or between individual differences
or more plainly marked varieties and sub-species and species.” ' And how often are we not
too prone to solve a difficulty in the way of identification, by at once cutting the Gordian
knot, and arbitrarily fabricating a new species, without seeking to determine or to trace the
connection of the specimen with some other form, of which it may be but a variety or mere
difference in shape.

Hundreds of British and foreign specimens of Carboniferous Streptorhynchus have
been assembled and carefully examined, but after much research and uncertainty from not
finding characters of sufficient permanence to warrant the establishing of distinct species,
I resolved (provisionally so, at least) to retain but one, of which S. crenistria
(Phillips) may be considered the type, and to describe under separate heads, but with

1 Darwin ‘On the Origin of Species.’

124 BRITISH CARBONIFEROUS BRACHIOPODA.

varietal designations only, those few forms whose connection with the typical shape could
not be entirely established; and by so doing I hope to concur with the views of those
paleontologists who are not disposed to go so far as I feel inclined to do. No
trouble has been spared in the selection and illustration of the most important and
characteristic forms assumed by the species and its varieties, and many more intermediate
shapes could have been figured, had space permitted.

SrREPTORHYNCHUS CRENISTRIA, Pdillips, sp. Pl. XXVI, fig. 1, Pl. XXVII, figs. 1—5
and 10? Pl. XXX, figs. 14—16.

SprrireR CRENISTRIA, Phillips. Geol. of Yorkshire, vol. ii, pl. ix, fig. 6, 1836.
— seEnruts. Ib., fig. 5.
Lrerta@na aNomaLa, J. de C. Sow. Min. Con., tab. dexv, figs. 1’ (but not 144°),
1840.
ORTHIS UMBRACULUM, var., Portlock. Report on the Geology of the County of London-
derry, Tyrone, and Fermanagh, pl. xxxvii, fig.
5, 1843.
— — De Koninck. Animaux Fossiles du Terrain Carbonifére de la
Belgique, p. 222, pl. xii, figs. 4—7, 1843.
— aquaprata? M‘Coy. Synopsis of the Characters of the Carb. Fossils of
Ireland, pl. xx, fig. 18, 1844.
— Becuer. Ib., pl. xxii, fig. 3.
— comata. Ib., pl. xxii, fig. 5.
— capuca. Ib., pl. xxii, fig. 6.
Lepr@ena Suarrel, Morris. Catalogue, p. 138, 1854.
STROPHALOSIA STRIATA, Morris. Catalogue, p. 155, 1854, (part). Min. Con., tab.
dexv, fig. 1% only.
LEPT@NA CRENISTRIA and L. sENILIS, M‘Coy. British Paleozoic Fossils, pp. 450 and
452, 1855.
Ortuis Kroxvuk, Hall. Iowa Report, pl. xix, fig. 5, 1858.
— rosusta. Ib., pl. xxviii, fig. 5.
STREPTORHYNCHUS CRENISTRIA, Dav. Mon. of Scottish Carb. Brach., p. 32, pl. i,
figs. 16—22, 1860.

Spec. Char.—Very variable in shape, transversely or longitudially semicircular ; hinge-
line straight, shghtly exceeding or somewhat shorter than the greatest width of the shell;
cardinal angles rounded or prolonged with acute terminations; ventral area variable in
width, flat, and divided by a fissure covered with a pseudo-deltidium ; dorsal area linear.
Ventral valve variable in its curves, slightly convex at the beak, flat in the middle, and
partly concave near and at the margin, or more or less regularly convex throughout ; beak
straight, produced, and often twisted or irregularly inclined to one side. Dorsal
valve moderately or extremely convex. Surface of both valves covered with numerous

—

STROPHOMENA. 125

strong, radiating, rounded striae with flattened interspaces of variable width, partly occupied
by one or two smaller striae, the ribs and interspaces being, at the same time, closely
intersected by fine concentric lines or striz, giving to the longitudinal ones a crenulated
appearance,

In the interior of the ventral valve, a strong hinge-tooth is situated on either side at the
base of the fissure, and strengthened by small dental or rostral plates ; the muscular im-
pressions form a saucer-shaped depression, partially surrounded by a slightly elevated ridge ;
the adductor or occlusor (A) occupies the central portion, and forms two small elongated
depressions, separated by a slightly elevated mesial ridge, and on either side are the larger
scars (R), apparently composed of two parts, the anterior or central being due to the
divaricator, while the other or outer one would be produced by the ventral adjustor? In
the interior of the dorsal valve, the cardinal process (J, to which were attached the
divaricator muscular fibres, P]. 27, fig. 6, 7) is composed of two testaceous projections ; the
socket plates are large, and partially united to the lower portion of the cardinal process.
Under these, on the bottom of the valve, may be seen the quadruple impressions left by
the occlusor, and which occupy above one third of the length of the valve, and are arranged
in pairs divided by a short rounded median ridge.

, Dimensions and relative proportions very variable ; some examples have attained or
exceeded three lines in length, by four in width, the depth varying also from a few lines to
about two inches.

Obs. Several paleontologists have already coincided in the belief that 8. senc/is is
nothing more than a different state of 8. crenistria, viz., in which the shell has attained an
excessive depth or degree of convexity, accompanied bya very large area. Professor M‘Coy
justly states S. Siarpei to be an undoubted synonym; and he might have said as much of
O. Bechei, for the so-termed species has been made out of a crushed imperfect cast or
impression of the same derived from the Carboniferous slate of Whiling Bay, Younghall,
Ireland, as may be seen from an inspection of the original specimen in Sir R. Griffith’s
collection. O. caduca is a small flattened valve of &. crenistria, or of var. arachnoidea ?,
the original specimen in Sir R. Griffith’s possession being derived from a black Carboniferous
slate at Rahoran, Fivemiletown, Ireland. O. comata is founded on a fragment of dorsal
valve ; for the original specimen in Sir R. Griffith’s collection shows the cardinal process,
although not represented in the ‘Synopsis ;’ the strize are also not so close and regular as in
the Irish author’s enlarged illustrations, but agree more with those of S. crenistria, to which
the specimen should be referred; and I cannot help feeling somewhat surprised that any author
could fabricate a species upon such insufficient material us the third part of single valve
must naturally be. In his work on the ‘ Cambridge Paleozoic Fossils,’ while describing
S. crenistria, Professor M‘Coy justly observes that “the striation is very variable, according
to the state of preservation: in some the principal striz, being nearly a line apart, and
the intervening flat spaces having very distinct, longitudinal, fine lines, internally punctured,
_ the middle one largest and crossed by fine, close, deep, irregularly transverse wrinkles; in

126 BRITISH CARBONIFEROUS BRACHIOPODA.

others, the imtervening striz nearly equal the principal ones in size, and the shell appears
more closely and coarsely striated sub-alternately : but both extremes may be seen on the
one specimen, and the differences are clearly the result of the loss of one or more layers of
shell.” I have also had the advantage of being able to examine typical examples of Pro-
fessor Hall’s O. Keokuk and O. robusta, which were kindly presented to me by Mr.
Worthen, and am thus enabled to affirm that these American shells cannot be specifically
distinguished from British varieties of S. crenistria.

For a long time I felt puzzled how to deal with a certain curious fragmentary ventral
valve, figured by Mr. J. de C. Sowerby, in the ‘ Mineral Conchology,’ under the designation
of Leptena anomala (tab. 615, fig. 1, 4), and which I have also represented in Pl. XXX, fig.
15. ‘This shell was subsequently referred by Messrs. Salter and Morris to the genus
Strophalosia, and wnited with it under the same denomination was Productus striatus ;
but here a double error has been committed, for the shell in question is neither a
Strophalosia, nor does it belong to Productus striatus, which is an entirely different
species, although so confounded likewise by Mr. J. de C. Sowerby. Having received
from Mr. Burrow some curiously shaped examples of Strept. crenistria, (Pl. XXX, fig. 14),
I at once perceived that Zept. anomala was no other than a malformation of Phillps’s 8.
senilis, and consequently a Streptorhynchus, while the Mytilus striatus of Fischer belongs
to the genus Productus. O. quadrata was created for a very small imperfect ventral
valve of a Streptorhynchus, which looks very like a young S. crenistria ; and the shell, such
as it is, belongs to Sir R. Griffith, and is said to have been found in calp at Ballintrillick,
Bundoran, Iveland. Its striation is exactly similar to that of crenzstrza, and to which it
is referred at least provisionally, the material being too imperfect to admit of its
being regarded as a well made-out species. Such are some of the undoubted synonyms
of Phillips’s species, and to which I would have added others, but for the reasons already
given.

S. crenistria appears to have had a very extended vertical range, and is recurrent from
the Devonian if not Silurian period? In the Carboniferous rocks, it is found in all the
stages, from the lowest beds (such as the Lower Carboniferous Red and Yellow Sandstone of
Kildress) up to the highest beds above the Mountain or Carboniferous Limestone. It is
also a far-spread species, having been found in various parts of Europe, America, Asta, and
Australia, everywhere assuming the same shape and variety.

In England, it occurs at Bolland, Kendal, Settle, the Isle of Man, &c.; in Scotland,
at Bowertrapping, three miles south of Dalry, and in many localities in Lanarkshire,
Renfrewshire, Dumbartonshire, Ayrshire, &c. It was figured by David Ure, in his ‘ History
of Rutherglen and Kilbride (pl. xiv, fig. 19), as far back as 1793. In Ireland, it occurs
in many localities; among which may be mentioned Hook, Bundoran, Ballyduff,
Millecent, &.

In Belgium, it is found at Visé and Tournay, &c. In America at Keokuk, lowa;

STROPHOMENA. 127

Warsaw, Nauvoo, St. Clair county, Illinois, &c. In India, at Moosakhail, &c., in the
Punjaub. It was found also in Spitzbergen, and in Australia, &c., &e.

Var. A.—Srreprornyncnus Aracunorpra, Phillips, sp. Pl. XXV, fig. 19—2I1,
Pl. XXVI, fig. 2, 3, 4 (lower figs.), 5, 6.

SPIRIFER ARACHNOIDEA, Phillips. Geol. Yorks., vol. ii, pl. xi, fig. 4, 1836.

ORTHESINA PoRTLOCKIANA, Semenow. Ueber die Fossilien des Schlesischen Kohlen-
kalkes, pl. ii, fig. 1, 1854.

Ortuis aRracHNorpEA, De Verneuil. Geol. of Russia, vol. ii, pl. x, fig. 18, 1845.

Professor Phillips describes his S. arachnoidea as “very depressed, truncato-orbicular,
hinge-line wide as the shell; striz fine, sharp, and continually subdivided ; upper valve
convex, asin S. resupinata.” ‘This description would certainly suit many specimens of
true S. crenistria ; but the figure in the ‘ Geology of Yorkshire’ would not indicate a shell
with a convex valve, such as that possessed by the Martins species, and was evidently
intended for those very depressed varieties in which the valves were almost flat or but
very slightly convex, one of them being even at times a little concave from the middle to
the margin, as will be found represented in our Pl. XXV, fig. 19—21; Pl. XXVI, fig. 2,
3, 4. Such, at any rate, is the shell we can conceive as having been intended for S.
arachnoidea. 'The area in this is narrow, while the striation is entirely similar to what
we have already described. ‘This variety or variation in shape of 8. crenistria generally
occurs in the same localities where the more convex forms are met with. .

Professor Phillips mentions Stradon, Haltwhistle, Allenheads, near Heskel Newmarket.
It is found also at Rutcheugh, and other places in Northumberland; in Scotland, in
the localities already enumerated ; while im Ireland, it occurs at Curragh, Ardmore, Kildare,

Kildress, &., &c.

Var. B.—S. Ketiu, MCoy. Pl. XXVII, fig. 8.

Ortats Kevii, M‘Coy. Synopsis of the Characters of the Carboniferous Fossils of
Ireland, p. 124, pl. xxii, fig. 4, 1844.

In shape, this species or variety? is marginally semicircular and slightly indented in
front, the hinge line being a little shorter than the greatest width of the shell. Ventral
area narrow, and divided by a triangular fissure covered by a pseudo-deltidium. The

128 BRITISH CARBONIFEROUS BRACHIOPODA.

ventral valve is slightly concave, the beak alone presenting a small convexity ; while the
dorsal one is moderately convex, with a mesial furrow or depression. The surface of both
valves is closely covered with numerous radiating, imbricated strie, a smaller one or two
intervening between the larger, as in S. crenistria. The typical specimen measured, length
193, width 283, depth 5 lines.

Professor M‘Coy has stated that his species “seems to be constantly distinguished from
O. crenistria, by its deep rounded mesial furrow, which indents the frontal margin ;”
but it is not always more convex than S. crenistria, nor are the angles in the last always
acute, for many examples had them rounded, as in 8. Kedlii. It is quite true that the
striation is so variable a character as to be of little use in specific distinctions, in the
British species of Streptorhynchus ; but, at the same time, I cannot allow that, in all the
examples of S. Ae//z that have come under my observation, the striation was finer, closer,
or more equal than is commonly the case with S. crenzstria, although such is the case in
many individuals.

In England, S. Kel/ii has been found in the Black Rock, Clifton. In Scotland, it
occurs in Ayrshire. In Ireland, at Monaghan; Annghilla, three miles south-west of
Ballyganty in Tyrone, &c.

Var. C.—S. cytinprica, M‘Coy. Pl. XXVII, fig. 9.

_ Ortuts cytinpRica, M‘Coy. Synopsis of the Characters of the Carboniferous Fossils
of Ireland, p. 123, pl. xxii, fig. 1, 1844.

Almost circular, hinge-line shorter than the greatest width of the shell, with rounded
cardinal angles: area triangular, not very wide; fissure covered by a pseudo-detidium.
Ventral valve convex at the beak, concave from near the middle to the margin; dorsal
valve very convex, almost geniculated. Surface covered with numerous radiating striz,
of which two or three smaller ones intervene between the larger ones. Of this beautiful
species or variety (?) I have never been able to obtain the sight of any other besides the
type, which measures eighteen lines in length, by twenty-one and a half in breadth,
and ten in depth.

Professor M‘Coy observes that, in this species, the striation is similar in character to
that of O. crenistria, O. Kellii, and L. euglypha, but that the form at once distinguishes
it from every known species.

It is at all times hazardous to make a new species upon the inspection of single
examples ; and as my knowledge in the present instance does not extend beyond the one
figured in the ‘Synopsis, I dare not venture to conjecture too closely as to its probable
affinities or variations in shape. The original example in Sir R. Griffith’s collection is
said to have been found in Arenaceous Limestone at Castle Espie, Comber, Ireland.

ORTHIS. 129

Var. D.—S. raviauis, Phillips. Pl. XXV, figs. 16—18.

Sprrirer RADIALIS, Phillips. Geol. of Yorks., vol. ii, pl. xi, fig. 5, 1836; and Dav.,
Mon. of Scottish Carb. Brachiopoda, pl. i, figs. 24,
25, 1860.

Shell variable in shape ; transversely or longitudinally semicircular ; hinge-line usually
shorter than the greatest width of the shell. Dorsal area of moderate width ; fissure closed
by a pseudo-deltidium. Valves moderately convex, the dorsal one being the deepest, with
sometimes a slight depression near the front of the ventralone. Surface covered with strong
radiating striz, with intervening smaller ones, crossed by imbricated lamella and deep
concentric lines or interruptions of growth.

This species or variety (?) does not appear to have attained the large dimensions of S,
crenistria, but the following average measurements may be given:

Length 17, width 21, depth 7 lines.
Sth LO Stay aL aie de Gp

The interior details do not appear to differ from those of 8. erenistria ; but on a young
specimen from Gare there appeared to exist a small circular foramen at the extremity of
the beak, similar to what we see in some species of Strophomena ; the aperture does not,
however, exist in full-grown individuals, and thus shows that the animal could dispense
with its temporary moorage.

The striz differ also much in different specimens, from the larger ones being either closer
or more widely separated, two or four smaller ones occupying the interspaces. It must
be, however, observed that it is difficult at times to distinguish certain individuals of | 8.
radialis from others of crenistria.

Professor Phillips mentions Florence Court, near Enniskillen, as the locality whence
his type was obtained ; but the figure in the ‘ Geology of Yorkshire’ is very incomplete, and
drawn from a crushed specimen. Good examples have been collected at Whatley, near
Frome, in Somerset ; at Gare and Middleholm, in Lanarkshire, Scotland ; and at Middleton,
in Ireland.

Genus—ORTHIS.

The genus Orthis forms a well-characterised group, especially numerous and abundant
in the Silurian and Devonian systems, is considerably reduced during the Carboniferous
period, to appear no longer (?) in subsequent stages. Four species alone have been
hitherto discovered in the Carboniferous rocks of Great Britain.

17

130 BRITISH CARBONIFEROUS BRACHIOPODA.

Ornrals rEesuPinata, Martin, sp. Pl. XXIX, figs. 1—6. Pl. XXX, figs. 1—5.

CONCHYLIOLITHUS ANOMITES RESUPINATUS, Martin. Petrif. Derb., tab. xlix, figs. 13,
14, 1809.
TEREBRATULA RESUPINATA, Sow. Min. Con., tab. 325, Feb., 1822.
SPIRIFERA RESUPINATA, Phillips. Geol. Yorks., vol. ii, pl. xi, fig. 1, 1836.
— CONNIVENS. Ib., fig. 2.
— RESUPINATA, V. Buch. Mem. Soc. Geol. de France, vol. iv, pl. x, fig. 32,
1840.
OrtHIs RESUPINATA, De Koninck. Déscription des Animaux Fossiles de la Belgique,
pl. xiii, fig. 9, 1843.
ATRYPA GIBBERA, Portlock. Report on the Geology of Londonderry, Tyrone, and
Fermanagh, pl. xxxvili, fig. 1, 1843.
OrTHIs LATIssima, M‘Coy. Synopsis of the Carb. Limest. Fossils of Ireland, pl. xx,
fig. 20, 1844.
— aqipBera. Ib., pl. xviii, fig. 9.
— ReEsuPINATA, Dav. ‘Introduction,’ pl. vii, fig. 135, 1853.
— _ M‘Coy. British Paleozoic Fossils, p. 449, 1855.
= — Dav. Scottish Carb. Brach., p. 28, pl. i, figs. 11, 12, 13, 1860.

Spec. Char. Shell transversely oval or elliptical ; valves convex, sometimes gibbous ;
hinge-line straight, much shorter than the greatest width of the shell, with rounded
cardinal angles. Dorsal valve generally the deepest, regularly and evenly convex, or
slightly flattened and depressed along the middle to the front, area narrow. Ventral
valve variable in its curves, moderately convex throughout, or at the rostral portion only,
becoming flattened or slightly concave near the lateral and frontal margins. ‘The frontal
margin presents a uniform or undulated curve, indenting to a lesser or greater extent the
margin of the opposite valve. Beak small and moderately incurved ; area triangular, with
an open fissure. Exteriorly, the valves are closely covered with numerous fine, thread-like,
rounded, radiating strize, which increase in number by interstriation and bifurcation at
variable distances from the beaks, and at intervals the striz themselves augment in
thickness and prominence, producing small, hollow, thread-like, tubular spines, which
become more numerous towards the margin. The intimate shell structure is perforated
by innumerable canals, of which the exterior orifices, in the shape of minute punctures,
cover the entire surface of the valves.

In the interior of the ventral valve, the dental plates extend to some distance along the
bottom of the shell, and between these a small rounded or angular ridge divides the
muscular scars, which thus form two elongated depressions margined on their outer sides
by the prolonged basis of the dental plates. The adductor or occlusor leaves a small,
not always clearly defined impression on either side of the mesial ridge, and it is probable

ORTHIS. 131

that the larger impressions, termed divaricator (r), in our figures of this species (as well
as of O. Michelini), is apparently composed of two parts, the anterior or central being the
cardinal or divaricator, while the other, the posterior or lateral (which is parallel), may
belong to the ventral adjuster ?

In the dorsal valve, the fissure is almost entirely occupied by a moderately produced
shelly prominence or cardinal process, to which were no doubt affixed the divaricator
muscular fibres. ‘The inner socket walls are somewhat prolonged under the shape of pro-
jecting laminz, and to the extremity of which free spiral arms may perhaps have been
attached (?); while under this shelly process a longitudinal ridge, with a wide, flattened space
on either side, separates the quadruple impressions of the adductor or occlusor muscles ;
these last producing two oval-shaped depressions, placed obliquely one above the other,
and separated by lateral elevations branching from the central ridge. Vascular impressions
and ovarian markings are at times clearly observable in the interior of both valves.

Dimensions and degree of convexity very variable two extremes have measured—

Length, 32; width, 41 ; depth, 21 lines (the largest example I have seen).
Std On oy Clhe gle iam

Obs. O.resupinata is acommon, well-known, and widely spread Carboniferous shell. Its
exterior appearance has been often described and illustrated, but not always properly under-
stood. In shape it is subject to considerabie variation, and hence the specific denominations
of resupinata, connivens, gibbera, and latissima, which appear to Mr. Morris and myself to
have been applied to what we must regard as different states of a single species ; and in my
plates will be found represented some of the most remarkable shapes. The striation is also
finer in some specimens than in others ; and certain examples show, more than others do, the
small drop-like elevations from which originate the little thread-like spines, which are
generally broken close to the surface of the valves in a large number of specimens.

Interiorly, some unimportant variation in detail may likewise be occasionally observed
and which I have endeavoured to illustrate.

In England, O. resupinata abounds in the Carboniferous limestone and shales of
many localities, such as at Greenhow Hill ; Hawes, Otterburn ; at Dovedale, in Derbyshire ;
the Isle of Man; Lowick, Northumberland; Settle, Malham Moor, Withgell, Yorkshire ;
at Ulverston, Bolland, &c.

In Ireland, it is found at Tyrone, St. John’s Point, Dunkineely, Cornacarrow, Ennis-
killen ; Cruiceroth, near Drogheda, County Meath; Little Island; Cornagrade, Bundoran,
Cookstown, Millecent, &c.

In Scotland, it occurs at Gare, Raes Gill, Middleholm and Brockley, near Lesmahago,
Capel Rig, Hast Kilbride, &c., in Lanarkshire ; in Ayrshire, at Auchenskeigh, near Dalry,
West Broadstone, Beith, &¢; in Dumbartonshire, at Castlecary ; in Stirlingshire, at
Balglass Burn, as well as in the Campsie Main Limestone and Corrieburn beds. It
occurs also in Midlothian and other Scottish counties.

On the Continent, it is not rare at Visé and Tournay, in Belgium, &.

132 BRITISH CARBONIFEROUS BRACHIOPODA.

Ortuis Kryserninciana, De Koninck. Pl. XXVIII, fig. 14.

Ortuts Keysertinciana, De Koninck. Déscription des Animaux Fossiles qui se trou-
vent dans le Terrain Carbonifére de Belgique.
p- 230, pl. xiii, fig. 12, 1843.

Spec. Char. Shell transversely oval or sub-quadrate, with rounded angles ; ventral valve
convex, and much deeper than the dorsal one, with a deep longitudinal median sinus or
groove, which extends from the extremity of the incurved umbonal beak to the front, this
valve being likewise the longest and largest, on account of the umbonal beak being more
elevated than the level of the beak and area of the dorsal one; area narrow. Dorsal
valve straight, flattened, and sometimes slightly concave from the extremity of the beak to
the front, the lateral portions sloping gently on either side ; area triangular, flattened, and
bent backwards ; beak small, angular, slightly convex, and on a level with the area; fissure
triangular, open; margin moderately flexuous. Exteriorly, each valve is covered with
numerous thread-like, rounded, radiating strix, which increase in number by the means
of numerous interstriations and bifurcations from the extremity of the beak to the front ;
the strize at intervals augmenting in thickness as well as projection, and giving rise to
small thread-like spines (broken close to the surface in the generality of specimens).
Numerous concentric lines of growth are also observable on the valves, which are likewise
perforated by minute tubuli. Interior unknown.

Two specimens have measured—

Length 11, width 123, depth 6% lines.
3 Se ag ie a, Sy CR

Obs. ‘This interesting and well-marked species was first brought to my notice as
British by Professor de Koninck, who had received a specimen from England, but without
locality ; and it was only after some research that I learnt that Mr. Burrow had found
several examples in the Carboniferous limestone of Settle, in Yorkshire, this being also the
only British locality, with which I am at present acquainted, wherein the shell has been
discovered. O. Keyserlingiana cannot be confounded with O. resupinata, on account of its
peculiar and different shape, although the striation is very similar in both. In Belgium,
it lias been found occasionally at Visé.

Ortats Micueuint, ZL. Hveil/é. Plate XXX, figs. 6—12.

TeREBRATULA Micue1ini, L’Eveilé. Mem. de la Soc. Géol. de Frarce, vol. ii, p. 39,
pl. ii, figs. 14d—17, 1835.
Serrrrera FILTARIA, Phillips. Geol. of Yorks., vol. ii, pl. xi, fig. 3, 1836.

ORTHIS. 133

Orrars Micue.ini, De Koninck. Desc. des Animaux Fossiles du Terrain Carb. de la
Belgique, pl. xiii, figs. 8 and 10° 4, 1843.
— pivaricata. M‘Coy. Synopsis of the Carb. Fossils of Ireland, pl. xx, fig. 17,
1844.
— orrcuLaRis. Ib., fig. 19.
— Micuewint. De Verneuil et De Keyserling. Geol. of Russia, vol. ii, pl. xii,
fig. 7, 1845.
— — Semenow. Ueber des Fossilien des Schlesischen Kohlenhalkes,
tab. iii, fig. 11, 1854.
— — M‘Coy. British Paleozoic Fossils, tab. iii, fig. 11, 1854.
— Micwewini. var., Buruinetonensis, Hall. lowa Report, pl. xii, fig. 4, 1858.
—_ — Dav. A Monograph of the Carb. Brach. of Scotland, pl. i, figs.
7—10, 1860.

Spec. Char. Shell depressed, almost circular or subtrigonal, as wide or wider than
long, with greater width near the frontal margin, this last assuming a gentle outward or
slightly inward curve ; hinge-line much attenuated, not above one third the width of the
shell, sometimes less ; ventral area small, but rather larger than that of the opposite valve,
and divided by a fissure which is almost entirely filled up by the cardinal process of the
dorsal valve. Ventral valve either moderately convex, with a slight depression commencing
about the middle and extending to the front, or flattened throughout with the exception of
the beak, which is small, shghtly incurved, and prominent. Dorsal valve, moderately and
uniformly convex, or gently depressed towards the front. Surface of both valves closely
covered with thread-like, radiating, rounded striz, which increase in number by means of
numerous interstriations and bifurcations, while from all the little ribs hair-like hollow spines
project and become more closely packed towards the margins. Intimate shell structure
perforated by small canals, of which the external orifices, under the shape of punctures, cover
the entire surface of the valves.

In the interior of the dorsal valve, the cardinal process is situated between two pro-
jecting Jaminze (which perhaps afforded attachment to the spiral arms) while under this
shelly process a narrow median longitudinal ridge separates the quadruple impressions of
the adductor or occlusor muscle; these last producing on either side two oval-shaped
depressions, one placed above the other, and separated by lateral elevations branching
from the central ridge.

In the interior of the ventral valve, the dental plates extend to some distance along the
bottom of the shell, and between these are situated the muscular impressions. At the
base of the fissure, and between the dental plates, may be observed a horizontally striated
impression, which may perhaps be due to the pedicle muscle ; under this a smaller median
oval depression was produced by the occlusor, while the larger elongated depressions on
each side of this are apparently formed of two parts, the anterior or one close to the
occlusor being the cardinal or divaricator, while the other, the posterior or lateral, which
is parallel, may belong to the ventral adjustor? Ovarian and vascular impressions are
also visible. |

134 BRITISH CARBONIFEROUS BRACHIOPODA.

Dimensions variable ; three examples have measured—
Length 15, width 163, depth 5 lines.
St.) Ose yess LSS Ya 35,
2 oy aS CL AL 5 pote a

Obs. O. Michelini is a common and far-spread Carboniferous species, always recog-
nizable, and easily distinguished from O. resupinata and O. Keyserlingiana both by external
shape and by interior differences, which last are evinced in the narrowness of the median
ridge, and less inclined slope of the adductor or occlusor muscular impressions ; while in the
dorsal valve the space occupied by the adductor, divaricator, and ventral adjustor muscles
is wider than in O. resupinata. There is also a singular impression, marked Nin
fig. 9, which is with some uncertainty attributed by Mr. Hancock to the pedicle muscle.
The striation in O. Michelini differs also from that of O. resupinata and O. Keyserlingiana
by the absence of that peculiar dilatation of some of the striae before the occurrence of a
spine-like projection, and the remarkable abrupt diminution of the swollen ridge beyond
the spine, which produces those elongated drop-like mark, so visible over the surface of
the last-named species. Professor De Koninck, who in 1843 first noticed the spiny
investment of the shell under description, expressed the opinion that the dorsal
valve was alone so adorned; but a careful examination of many specimens has convinced
me that spines existed on both, although perhaps more numerously spread on the dorsal
valve. The spines were likewise more abundant on some examples than on others,
nor do they seem to have anywhere exceeded about a quarter of an inch in length.

Orthis Michelini appears also to have varied less in shape than the preceding species ;
the shortness of the hinge-line is, however, in some specimens very remarkable.

O. Michelini abounded where it occurred, and especially so in certain shales at the top
of the Mountain Limestone, such as at Clattering Dykes, on the middle of Malham Moor, in
Yorkshire; nor is it rare in the Mountain or Carboniferous Limestone of Settle, Bolland,
Fountain Fell, the Isle of Man, &c.

In Ireland, it occurs in the Carboniferous Limestone and shales at Lisnapaste, Little
Island, Millecent, Ballyduff, Bruckless, Malahide, Old Leighlin, &c. It may also be
collected by millions (in the condition of internal casts and impressions) in the calciferous
states of Ballyseedy, County Kerry.

In Scotland it is also very plentiful in certain localities, such as at Gateside, near
Beith, where detached valves occur by thousands in the same stratum of shale whence
David Ure collected his specimens of the species... In Lanarkshire, it occurs at Langshaw
Burn, Brockley, and Middleholm, near Lesmahago, Auchentibber, Calderside, and Phillips-
hill, High Blantyre; Capel Rig, East Kilbride, &c. In Renfrewshire, at Orchard Quarry
Thornliebank ; Barrwood and Howood, near Paisley. In Ayrshire, at Roughwood, West
Broadstone, and 'Treehorn, near Beith, &c. In Stirlingshire it is found in several stages ;
and occurs also in Dumbartonshire, Fifeshire, &c.

’ David Ure appears to have been the first naturalist who figured this shell in Great Britain ; for figs. 13

and 14 of the fourteenth plate of the ‘History of Rutherglen,’ published in 1793, evidently belong to the
species under description.

PRODUCTID AS. 135

In Belgium, it is common in the limestone and shales of Tournay ; but rarer at Visé.
In Russia, at Cosatchi-datchi, &c. While in America it has been collected at Burlington,
fowa; Quincy, Illinois; Hannibal, Missouri, &c.

Orruis? antiquata, Phillips. Plate XXVIII, fig. 15.

TEREBRATULA ANTIQUATA, Phillips. Geol. Yorks., vol. ii, pl. xi, fig. 20, 1836.
RHYNCHONELLA ANTIQUATA, Morris. ‘Catalogue,’ p. 146, 1854.

Spec. Char. Somewhat elongated oval; hinge-line straight, shorter than the greatest
width of the shell; ventral valve deep and convex, but flattened towards the front ; beak
small, incurved ; area narrow, with an open triangular fissure (?). Dorsal valve shallow, and
divided into three lobes, of which the two largest diverge from the umbone to the lateral
margins, the third or the less produced forming a small median elevation, originating near
the middle, and extending to the front, where the valve assumes a somewhat triundate margin
and appearance. Surface smooth; length 4, width 3, depth 23 lines.

Obs. Of this little shell I have seen but one example—that described and figured by
Professor Phillips, and which is stated to have been obtained at Bolland, and now forming
part of the Gilbertsonian collection in the British Museum. All endeavours to procure the
sight of another example have proved unavailjng; so that my observations have been con-
fined to the examination and description of the original type, which looks more like a small
Orthis than a Terebratula or Rhynchonella, and it is therefore here at least provisionally
located under the genus Orthis. Professor Phillips describes his species in the following
words :—“ a very singular, small Brachiopodous shell (perhaps Producta) of an oval figure ;
lower valve convex ; upper plane, with two diverging convexities ; hinge-line straight.”
Upon such insufficient material, the species itself can only be admitted as provisional.

Family—PRODUCTID As.

The Propvuctipaz have been divided into four groups, viz., Productus, Aulosteges,
Strophalosia, and Chonetes ; but they all appear to bear so natural and indeed so intimate
a relation towards each other, that it is very questionable whether the last three should be
considered more than simple sub-genera or modifications of Propuctus ; and this is also
the opinion of Professor de Koninck, to whom science is indebted for a valuable monograph:
of the many forms of which this family is composed.

All the species at present known are restricted to the limits of a portion of the
Paleozoic period. No British examples of Carboniferous Strophalosia or Aulosteges have

136 BRITISH CARBONIFEROUS BRACHIOPODA.

been hitherto recorded ; but a few forms of those sub-genera occur in equivalent rocks of
other countries, such as Belgium and India. In all British species of Productus and
Chonetes, the shell is more or less concavo-convex, oval, semi-oval, or angular, and generally
auriculated ; the hinge-line is straight and strong, with or without teeth and sockets for
the articulation of the valves. All well-authenticated species of Productus, hitherto
examined, have shown themselves to be edentulous, but whether this character was general
and without exception may remain a question for further consideration ; anyhow, the
dorsal valve must have turned on its long hinge-line with as much precision as in Chonetes,
which possessed regularly articulating teeth. It has been often asserted and believed that
Productus might be distinguished from its sub-genera by the total absence of an area; and
although this is the prevalent character of the genus, still in certain species, such as
P. sinuatus, a perfectly developed area is generally present in the ventral valve. ‘There
exists also an occasional tendency to the formation of hinge-area in several species, as may
be seen, for example, in the remarkable example of P. semireticulatus of which a
representation is given in Pl. XLII, fig. 5.

All species of Chonetes at present known have, in addition to the regular articulation,
an area in each valve, this being larger in the ventral than in the dorsal one, which is also
divided by a fissure, more or less arched over by a pseudo-deltidium, the cardinal process
of the opposite valve filling up and effectually closing any portion that might have other-
wise remained uncovered.

The external surface in Productus varies according to the species ; in some, it is almost
smooth, in others longitudinally and finely striated or coarsely costated, as well as inter-
sected by numerous concentric wrinkles or lines of growth. All the species appear to have
been furnished with tubular spines; in some forms they are small, delicate, and so closely
packed as to conceal every portion of the shell, with the exception of the area; while in
others they are irregularly scattered, and chiefly confined to the auriculate portions of the
valves. In certain species, the spines exceeded by four or five times the length of the
shell; and while some were almost as delicate as the hair of one’s head, others exceeded a
line diameter ; the dimensions of the shell having nothing to do with that of the spine,
for in some small species these were few and large, while the reverse has occasionally been
found to be the case with species of the largest dimensions.

Chonetes differs also somewhat from Productus by the manner in which its spines are
disposed along the cardinal edge, these last sloping outwardly, and increasing in length as
they approach the extremities of the hinge-line ; but in many species, in addition to these,
there existed on the surface of the valves small spines, disposed as in Productus.

The intimate shell-structure has been described by Dr. Carpenter to be perforated,
and that, where the shell is furnished with spines, the perforations are continued into
them, and that such passages are of more than average dimensions. In Productus the
internal surface of the dorsal valve is more or less convex, and presents in the middle of

ae

PRODUCTUS. 137

the hinge-lme, a prominent bilobed or trilobed projection or cardinal process Gahits
upper surface is often striated, and affords attachment to the cardinal or divaricator
muscles (Rr). Under this ‘a narrow longitudinal ridge generally extends to about half (or
more) of the length of the valve, and on either side are seen the ramified or dendritic
impressions, which we consider to be attributable to the adductor or posterior and anterior
occlusor muscle (A), but which are often situated so close to each other, on either side of
the mesial ridge, as to render the quadruple attachment not so distinct as could be desired ;
they are, however, well defined in P. /ongispinus, and in some other species. Outside,
and in front of these, are the two “ reniform impressions” (x). Their surface is generally
smooth, and bordered by ridges, which after dividing the occlusor muscles proceed in an
outward, oblique, or almost horizontal direction ; then turning abruptly backwards, they
terminate at a short distance from their origin. There exists also, in many species, but
not in all, two prominences (w), one on each side of the median ridge, and close to the
base of the muscular scars ; they are very apparent in Productus, but not observable in
Chonetes.

The internal surface of the valves (in all the family) is covered with innumerable
granulations, of which some have been thought by Mr. Hancock to have been “ probably
produced by the muscular bands, which retracted the margim of the mantle.” I will
now describe the internal appearances observable on the concave surface of the larger or
ventral valve. A narrow mesial ridge, originating under the extremity of the beak,
separates two large, elongated, ramified or dendritic impressions (a), which have in all
probability been produced by the adductor or occlusor muscle, although otherwise referred
by some Palzontologists. In advance of the larger scars, we sometimes perceive smaller
impressions closely connected with the larger ones above described (£), and which were
in all probability produced by a portion of the occlusors themselves. On either side of the
adductor or immediately under there exist two deep, longitudinally striated, sub-quadrate
impressions, which are due to the cardinal or divaricator muscles (rR). I have in vain,
hitherto, sought for impressions referable to the adjustor muscles ; but as no peduncular
aperture existed, such muscles may be supposed not to have existed: however, as the
valves in the species hitherto known of Productus possessed no teeth or sockets, and
therefore are not strongly articulated, as in the Zeredratulide, it is not impossible that the
adjustors may have been so arranged as to keep the valves adjusted to each other, and
that they thus acted as a substitute for a hinge.

The only poimt remaining to be here noticed in connection with the interior of this
valve are the deep concave, often sub-spinal, depressions (1), visible in some species, such as
P. giganteus, P. humerosus, &c., and which were hollows no doubt occupied by the spiral
arms, for it would seem impossible to conjecture otherwise, how they had originated.
Similar hollows could not of course be expected to be present in those species in which

1 See Pl. XXXVII, figs. 1—4.
18

138 BRITISH CARBONIFEROUS BRACHIOPODA.

the shell did not possess a sufficient thickness, as they never influenced the regular curve
or convexity of the exterior of the valve. In all the Propuctip™ we therefore find muscles
destined to open and close the valves, as well as evidence that they possessed spiral arms,
and which have been justly, I think, supposed to be brachial appendages, which subserved
at once the function of gills and of sustentation.

In Chonetes, the muscular impressions are somewhat similar to those of Productus, but
of more often comparatively smaller proportions, as may be perceived by a glance at the
figures I have given of both.

The determination and arrangement of the British Carboniferous species of Productus and
Chonetes has demanded a lengthened examination, for much confusion still existed among
the synonyms, notwithstanding the able and valuable researches of Professor de Koninck.
‘Through the kindness of several friends, I have been enabled to study the original types of
the larger number of species, as well as avery extensive series of specimens ; and although
I have rejected a great number of so-termed species, and been able to add several others
new to Great Britian, I should still urge further research upon these very interesting shells,
as it has not been always possible to determine the specific claims of some among them
with sufficient accuracy.

After much examination, and in some cases much uncertainty, the following twenty-
eight species have been retained, and which may be arranged in the following three

groups.*
1. Productus striatus, Fischer.
2 — giganteus, Martin.
var. hemisphericus, Sowerby.
| oO — latissimus, J. Sowerby.
4. — Cora, D’Orbigny.
5 — semireticulatus, Martin.
6. — costatus, Sowerby.
var. ? muricaéus, Phillips.
| he —_ longispinus, Sowerby.
1. Striati, or Semireticulati . . . . ra} sinuatus, De Koninck.

— humerosus, Sowerby.
Margaritaceus, Phillips.
— undatus, Defrance.

— arcuarius, De Koninck.

ae
|

— carbonarius, De Koninck.
— ermineus, De Koninck.
_ proboscideus, De Verneuil.
Wrightii, Davidson.

— tessellatus, De Koninck.

pa
er ee es — ee

=o 8
|

1 Those groups and species most nearly related have been connected by the means of abrace. It is
difficult, with words, to explain the exact contour, or shape, of such variable shells as the Producti; but

PRODUCTUS. 139

( 18. Productus seabriculus, Martin.
19. — pustulosus, Phillips.
20). — fimbriatus, Sowerby.
var. laciniatus, M‘Coy.
2. Spinosi Pale — punctatus, Martin.
var. elegans, M‘Coy.
22 — aculeatus, Martin.

23. — Youngianus, Davidson.

bo

ol
. .

— Keyserlingianus, De Koninck.

Z -— spinulosus, J. Sowerby.

26. — mesolobus, Phillips.

GUUNCOE ph ae VBL Gowesd Gee is de) 2 27. = plicatilis, Sowerby.
| 28. _ sublevis, De Koninck.

Propuctus striatus, Mscher. Plate XXXIV, figs. 1,—5.

Propuctus comorpEs, Dillwyn. An Index to the Hist. Conch. of Lister, p. 24 (not
of Sow.), 1823.
Mytitus striatus, Fischer. Oryct. du Gouy. de Moscou, p. 181, pl. xix, fig. 4, 1830.
PINNA INFLATA, Phillips. Geol. of Yorkshire, vol. 11, pl. vi, fig. 1, 1836.
PECTEN TENUISSIMUS, Lichwald. Bullet. Scient. de l’Acad. de St. Petersburg, vii,
p. 86, 1840.
Lima Watpatca, V. Buch. Kersten’s Archiv fur Min. Geogn., &c., p. 60, 1840.
Lepr@na aNoMALA, J. de C. Sow. Min. Conch., vol. vii, pl. 615, fig. 1, a, c, d (not
1 6, which belongs Streptorhynchus crenistria, var. senilis),
1841:
Propuctus LiM™rormis, V, Buch. Abhand. der Kénigl. Akad. der Wissens. zu Berlin-
aus dem Jahre, Theil. i, p. 22, pl. i, figs. 4, 5, and 6,
1841.
— striatus, De Kon. Desc. des Anim. Foss. du Syst. Carb. de Belgique,
pl. vi, fig. 10, and pl. viii bis, fig. 4, 1843.
= — De Verneuil. Russia and the Ural Mountains, vol. ii, p. 254,
pl. xvii, fig. 1, 1845.
— — De Keyserling. Reise in das Petschoraland, pl. iv, fig. 8, 8a,
and 84, and pl. v, fig. 1, 1846.
-- — De Kon. Mon. du genre Productus, pl. i, fig. 1, a—d, 1847.
STROPHALOSIA striaTa, Morris. Catalogue, p. 155, 1854.
Propuctus striatus, M‘Ooy. British Pal. Fossils, p. 473, 1855.

Spec. Char. Shell thin, exceedingly variable in shape, and often irregular; usually
much elongated, triangular, with acuminated beak and rounded front ;_ or broad, transversely
semicircular ; hinge-line always shorter than the width of the shell, sometimes exceedingly
so. Ventral valve moderately convex, rarely gibbous, without sinus; beak pointed, rarely
a glance at the figures will, I trust, remove all uncertainty. In order not to unnecessarily burden the list

of references, I have many times purposely omitted to allude to those catalogues or works in which the
species are named, but not illustrated.

140 BRITISH CARBONIFEROUS BRACHIOPODA.

projecting beyond the hinge-line; ears small, flattened, and from which project numerous
long slender spines ; surface covered with fine, thread-like, waving, radiating strize, which
increase in number at variable distances from the beak by the interpolation of other strie.
Spines few in number, and irregularly scattered over the surface. Dorsal valve concave,
following the curves of the opposite one, and similarly ornamented.

Dimensions very variable ; three British specimens have afforded the following measure-
ments :

Length 39, width 20 lines.
eA oD:
Pye AUS,

Obs. This species is very remarkable, on account of the various forms it is capable
of assuming, and has consequently not only been attributed to seven different genera,
but has received as many specific denominations. The shell and its history have
been minutely described by Professor de Koninck, as well as by some other authors,
but it was Lister who, in 1688, first noticed the shell, ‘ Hist. sive Synops. Conch.,’ pl.
468, fig. 27; although it received its first specific denomination from Fischer de Waldheim
in 1830, or shortly after. ‘The shell is sometimes so very irregular in its shape as to be
hardly recognisable, and although Professor M‘Coy states that he has seen some Irish
specimens one foot in length by five inches in width, I have never observed any examples
exceeding four inches in length. The space between the valves is also remarkably small,
and in no case have I ever noticed an area in either valve. In 1840, Mr. J.de C. Sowerby
confounded some specimens of the shell under description with a distorted imperfect valve
of Streptorhynchus crenistria, var. senilis, and consequently erroneously described the
species as possessing a large triangular hinge area. Mr. Morris has also fallen into the same
mistake, for he classes Fischer’s species in the sub-genus Strophalosia ; the reader is however
referred to p. 126 of the present monograph for further information upon the subject. The
spines are very numerous and closely packed upon the ears, Professor de Koninck having
counted as many as twenty-four on each of the auriculate expansions in certain specimens,
but that they are exceedingly rare on the surface of the shell. I have never seen any
perfect interiors of either valve, but fragments have shown that the details are very similar
to those of other species of the genus.

In England it occurs in the lower scar limestone of Settle, m Yorkshire ; the lower
carboniferous limestone, Park Hill, Longnor, in Derbyshire; the dark middle limestone of
Lowick, Northumberland, as wel] as of the Isle of Man, &c. No specimen has been
hitherto found in Scotland, and although Ardagh in Ireland is mentioned in Mr.
Kelly’s list, I have seen no specimen. In Belgium it occurs at Visé. In Russia,
in the valleys of Stolobenka and Prikcha (Valdai) in the Petschora, near Zvenigorod, &c.
In the Punjaub (India), &., &.

PRODUCTUS. 141

Propuctus eicantnus, Martin. Plate XXXVII, figs. 1—4; Plate XXXVIII, fig. 1;
Plate XX XIX, figs. 1—5; Plate XL, figs. L—3.

ANOMITES GIGANTEUS, Martin. Petrif. Derb., pl. xv, fig. 1, ]809.
— crassus, Martin. Ib., pl. xvi, fig. 2, 1809.
Propuctus GiGaNTEUsS, J. Sow. Min. Con., vol. iv, pl. 320, Jau., 1822.
— HEMISPHmRIcus, J. Sow. Ib., pl. 561, 1827.
PropuctTa GIGANTEA, Phillips. Geol. of York., pl. viii, fig. 5, 1836.
— avprita, Phillips. Ib., pl. vii, fig. 6, 1836.
— EpetsurcGensts, Phillips. Ib., pl. vii, fig. 5, 1836.
Lepra@Nna VARIABILIS, Fischer. Oryct. du Gouv. de Moscou, p. 144, pl. xxi, 1837.
Propuctus Gi@as oder aicanteus, Von Buch. Abhandl. der Konigl. Akad. der
Wissens. zu Berlin, aus dem Jahre, p. 19, 1841.
-— comorpEs, Von Buch. Ib., pl. i, figs. 1—3 (not Sow.).
Propucta HEMISPHARICA, D’ Adrchiac and De Vern. Trans. of the Geol. Soc. of
London, 2d series, vol. vi, p. 397, 1842.
Propuctus Gtcanteus, De Koninck. Animaux Foss. des Terr. Carb. de Belgique,
pl. vii, fig. 1, 1843.
—- comorpEs, De Koninck. Ib., pl. viibis, fig. 1 (not Sow).
Lepr@na Maxima, M‘Coy. A Synopsis of the Characters of the Carb, Limest. of
Ireland, pl. xix, fig. 12, 1844,
Propuctus strratus, EZ. Roberts. Atlas Géologique des Voyages en Scandinavie et de
la Commission Scientifique du Nord, pl. xx, fig. x, 1845
(non Fischer).
= GIGANTEUS, De Verneuil. Russia and the Ural Mount., vol. ii, pl. xvi, fig.
12, and pl. xvii, fig. 2, 1845; and P. Edelburgensis, ib.,
pl. xviii, fig. 2.
-- ~—— De Koninck. Mon. du genre Productus, pl. ii, fig. 1 ; pl. iti,
fig 1; pl. iv, fig. 1; and pl. ix, fig. 8, 1847.
— — M‘Coy. British Palzeozoic Fossils, p. 463, 1855.
— — Dav. The Geologist, vol. ii, pl. iii, 1859; and Scottish Carb.
Mon., pl. v, figs. 1—4, 1861.

Spec. Char. Shell large, varying in shape and striation according to age and specimen ;
somewhat transversely oval; hinge-line straight, exceeding the width of the shell, and
sometimes (though not commonly) possessing a narrow rudimentary hinge area in the
larger valve. Ventral valve greatly thickened, especially towards the middle, less so at the
beak, and near the margin; more or less gibbous, and often much dilated at the ears,
which are semi-cylindrically enrolled, and more or less defined. Beak moderately developed,
incurved, and overhanging the hinge-line near its extremity only. Exterior evenly convex,
or more or less deeply and irregularly furrowed, the surface being covered with a vast
number of longitudinal flexuous strize, which vary according to age and specimen, three or
more usually occupying the width of a line towards the middle or margin of the valves.
The striz are also at times confluent, bifurcating, or suddenly disappearing and again re-
appearing and increasing in number towards the margin of the valve. ‘They are likewise

142 BRITISH CARBONIFEROUS BRACHIOPODA.

contiguous or separated by sulci or interspaces of variable width. At irregular distances
the strize give rise to a few short, cylindrical, hollow spines, which are more numerous
upon the auriculate portions of the valve. Dorsal valve thin, concave, following the curves
of the opposite one, and similarly sculptured, the visceral portion and ears being also some-
times concentrically wrinkled, while the entire surface is crossed by minute concentric lines
of growth. In the interior of the ventral valve the divaricator muscular scars are imme-
diately under and outside of the adductor or occlusor ones, and lower down towards the
centre of the valves there are two deep subspiral depressions. In the interior of the dorsal
valve the cardinal process is trilobed and V shaped, under which a narrow longitudinal
ridge extends to about half the length of the valve, and on either side are situated the
ramified dendritic impressions of the adductor or occlusor muscle, while outside and in
front of these are the two “reniform impressions.” ‘The internal surface is covered with
innumerable asperities, and the shell structure perforated by canals. Dimensions variable,
four British examples measured—
Length 6 inches 2 lines, width 11 inches 6 lines.
ae) Se ae 7 10 5 a
4 POY Os Pa) pH On Ge
pan 6 kOe Ss Hs aw ee Olaeks
Oés. Of the many species of which the genus Productus is composed, this is certainly
the largest and most remarkable, some examples having attained eight inches in length by

9

twelve in breadth, but it is also most variable in its shape, so much so, indeed, that one
is at times seriously puzzled, and tempted to fabricate more than one so-termed species
out of its variations. ‘The shell has been several times minutely described since its first
discovery, but Palzeontologists are far from unanimous with reference to some of its sup-
posed synonyms. Martin’s figure of Anomites giganteus represents the adult typical shape
of the species, with its developed auriculate expansions, while the same author’s 4. crassus
illustrates an adult individual of the same, but in which the ears are broken or undeveloped,
and it is quite easy to find in the same quarry and bed specimens graduating from the one
into the other. In one, Plate XX XVIII, is represented, of the natural size, a very remarkable
example of the typical form, with unusually expanded ears, while in Plate XX XIX (fig. 3)
will be found a reduced illustration of a still more circular specimen than that upon which
Martin’s P. crassus was founded. ‘The greater number of Palzontologists have considered
P. hemisphericus a synonym of P. giganteus, and I am inclined to believe that they are
substantially correct, but it must be remembered that in this case the name has been, at any
rate, applied to two conditions of the species. James Sowerby’s original illustrations m ‘Tab.
328 of the ‘Mineral Conchology,’ which we consider the typical ones, appear to represent
what I take to be a local modification, which had better be described separately with the
varietal designation “ hemisphericus,’ while the figures of P. hemisphericus in Tab. 561
of the same work, published some five years later by Mr. J. de C. Sowerby, represent the true
adult condition of that shape of P. giganteus to which Martin had applied the denomination

PRODUCTUS. 148

“ crassus.” P. auritus of Phillips is another undoubted synonym, while P. Ldelburgensis
of the same author represents those examples of P. giganteus in which the valves are more
coarsely striated, with interspaces of almost equal or greater width, and of which a figure
will be found in Pl. XU, fig. 2, of the present work. ‘The striation is, however, sometimes
very variable and irregular, even on the surface of a same specimen, and I have at present
before me a large example in which the striz are small, regular, and contiguous for about
one inch and a half’s distance from the extremity of the beak, then comes a band of
about one inch and a quarter in breadth, wherein the ribs become suddenly reduced to
nearly half their original number, from many having become obliterated, and thus
having left interspaces of irregular width between the remaining striz ; again, for the last
two inches, the striae become suddenly smaller, twice as numerous, irregularly twisted,
unequal in their respective widths, and assuming every kind of modification until they
reach the margin. In this example, and in many similar ones, we have therefore com-
bined the striation of both the typical P. giganteus and its modification Ldelburgensis.
The term, P. maxima, was given by M‘Coy to that modification of P. yiganteus in which
the valves are uniformly convex and concave, without longitudinal furrows, while the so-
termed P. personatus was established on what is believed by some to be the internal cast
of a circular example of P. giganteus, but of which I am not yet perfectly satistied. We
now come to another form, which has by some been considered a synonym, by others a
variety, and by many a separate species, viz., P. /atissimus, Sow., and I confess that it is
not easy to satisfactorily determine which of the interpretations comes nearest the truth.
It has, however, appeared to me that if P. /atissimus is not a distinct species, it is certainly
a well-marked variety, and had’ better, at least for the present, be separately described.
Prod. Scoticus, Sow., and P. pugilis, Phillips, have been classed by Professor de Koninck
among the synonyms of P. giganteus ; but this is a mistake, for both those shells, of which
I have been able to study the original type, are synonyms of Prod. semireticulatus, as
will be hereafter shown.

In the young state P. g/ganteus varies almost as much as it does in the adult; it is
at times very slightly convex, while the number of strize are also far less numerous, these
last increasing in number as the shell becomes older, by the means of interstriation or
bifurcation. A very great disproportion in the respective thickness of the valves is also
usually observable, that of the ventral one being in certain examples five or six times
greater than that of the dorsal valve. The spines also were far more numerous in certain
specimens than in others, and in some specimens a row of short ones projected from close
to the cardinal edge of the ventral valve, but never as represented by Von Buch in PI. J,
fig. 1, of his monograph,’ such a restoration is founded on a supposition which no example
I have seen has ever warranted, but they occur sometimes as represented in his fig. 3.

Loc. Productus giganteus is common in the English grey lower carboniferous limestone

1 «Ueber Productus oder Leptaena Gelesen in der Akademie der Wissenschaften,’ 1841.

144 BRITISH CARBONIFEROUS BRACHIOPODA.

of Derbyshire; it occurs near Richmond and Thornton Wensleydale, in Yorkshire ; while
Addleburgh, Bolland, Fountainsfell, Ulverston, Aldstone Mcor, Hawes, Askrigg, Dentdale,
Rockeley, &c., are given by Professor Phillips as the localities in the carboniferous limestone
from whence his specimens were derived. It has also been found in the dark carbo-
niferous limestone of Lowick, Northumberland, as well as in the Isle of Man. In Scot-
land it characterises some of the lower stages of the carboniferous system, wherein
Brachiopoda have been found; thus at Braidwood Gill, in Lanarkshire, it is found for the
first time at 397 fathoms below the horizon of the “ Ell coal.” In Stirlingshire it occurs
in the Mill-Burn beds, Campsie. In the island of Arran, and in red limestone at Closeburn,
in Dumfriesshire; im Edinburgshire, at Joppa; in Haddingtonshire, at Cat Craig, near
Dunbar; in Peebleshire, at Carlops, &c. In Ireland, Mr. Kelly mentions that it occurs in
the carboniferous limestone of Cookstown, Millecent, Tankardstown, ‘Tornaroan, Drum-
reagh Etra, Castle Hspie, Armagh, Little Island, &e. On the Continent the species occurs
at Visé, Chokier and Temploux being, according to Professor de Koninck, the only localities
in Belgium where the shell has been found. It has been also obtained from several Russian
localities, such as Karova, Zerovskoi in the Oka of Mydynsk, on the Valdai, at Peredki,
in the basin of the Donetz, &c. In the Oural, at Kamensk and Biclobac in the river Isset,
&c. In Silesia it occurs at Altwasser, &c. In Carinthia, in the neighbourhood of
Bleiberg and Ratingen, and it has also been discovered at the top of Mount Misery, in
Bear Island, along with P. striatus and Punctatus,' &e.

Var.? Hvemispnaricus. Pl. XU, figs.4—9.

PRopUCTUS HEMISPHHRICUS, James Sowerby. Min. Conch., tab. 328, Feb., 1822 (not
tab. 561).
— — M‘Coy. British Paleozoic Fossils, p. 464, 1855.

Shell hemispherical or transversely oval, hinge-line usually exceeding the width of
the shell. Ventral valve evenly convex, ears more or less semicylindrically enrolled, and
sloping more or less gradually into the gibbous body. Surface covered with numerous
small, rounded, radiating, contiguous strize, which increase in number by bifurcation as
well as by the occasional formation of new striz between those already existing. The
spines are very few on the body of the shell, but a close row of small curved ones line and
curve over the cardinal edge. Dorsal valve very concave, following the curves of the
opposite one, and similarly ornamented. A few obscure concentric wrinkles may be
observed, on the ears of certain specimens. Interior similar to that of P. giganteus
proper, dimensions variable. 'T'wo specimens have measured—

Length 17, width 26 lines.
pee ema lp ss
1 Further details with reference to the foreign localities wherein this widely spread species has been

discovered, will be found in Professor de Koninck’s very valuable ‘Monographe du genre Productus,’
1847.

PRODUCTUS. 145

Oés. Much difference of opinion has been expressed relative to the shell under
description, and it was not until after much examination and hesitation that I determined
to provisionally retain the shells first figured by James Sowerby, in tab. 328 of the ‘Min.
Conch.,’ asa variety of P. giganteus—a view entertained by Prof. de Koninck, when pub-
lishing his monograph in 1847. Prof. M‘Coy, describes them as belonging to another
and distinct species ; so that the subject may still remain an open question, although I am
myself inclined to consider P. hemisphericus as nothing more than a local variety of Pro-
ductus giganteus? Mr. E. Wood, who has had occasion to collect 7” s¢¢éz some hun-
dreds of specimens of this and the typical shape, assures me that the one never occurs in
the same bed or zone along with the other; that the bed in which the P. hemisphericus
occurs runs for miles along Warfdale in Yorkshire, and that the layer is covered and filled
with closely packed specimens of this one fossil, which is also always exactly the same,
and much under the true P. geganteus bed. My reasons for supposing it a variety of P.
gigantens are based on the following consideration, viz., that I have several times seen large
examples of P. yiganteus evenly convex, and closely resembling some of the smaller
specimens of P. hemisphericus above described,' and it is well known that the longitudinal
furrows which cover the valves of many examples of Martin’s shell are not always present ;
that the striation of P. hemisphericus agrees likewise with that of many specimens of P.
yiganteus, and that the small curved cardinal spines so constantly present in the Warfdale
specimens are also observable in many undoubted large examples of Martin’s shell; and,
lastly, that the interior is smaller in both. I have also had the advantage of being able
to study James Sowerby’s original specimens of P. Aemisphericus, and found them to agree
with those from the gray carboniferous limestone of Warfdale, in Yorkshire.

Propuctus Latissimus, J. Sowerby. Plate XXXV, figs. 1—4.
Propuctus Latissimus, J. Sow. Min. Conch., pl. 350, Feb,, 1822.
— — Phillips. Geol. of Yorks., vol. ii, pl. viii, fig. 1, 1836.
— — De Koninck. Monographie du genre Productus, pl. ii, tig. 2,
and pl. iii, fig. 2, 1847.
= — Dav. Scottish Carb. Brach., pl. u, figs. 8, 9, 1861.

Spec. Chav. Shell thin, transversely elliptical or spindle-shaped, with a long, straight
hinge-line, the breadth of the shell being more than twice the length. Ventral valve
very much vaulted and convex, with a slight mesial longitudinal depression, the
gibbosity forming in profile more than a semicircle, while the passage from the body of
the valve mto the lateral expansions is usually so gradual as to become insensible. The
small flexuous striae which cover the surface augment by the means of numerous interca-

! In his work on ‘ British Paleeozoic Fossils,’ Professor M‘Coy has considered P. aurita to be a
synonym of P. hemisphericus ; and I feel convinced, that any one who examines the Gilbertson specimens of

the first (now in the British Museum) will class it among the synonyms of P. giganteus.

19

146 BRITISH CARBONIFEROUS BRACHIOPODA.

lations, and from which at intervals project short slender spines. Dorsal valve very con-
cave, following the curves of the opposite valve, and similarly sculptured. In the interior of
the ventral valve, the muscular impressions are located in the rostral portion of shell close
to the extremity of the beak.

Dimensions variable: a large example measured, length 2 inches, width 44 inches; a
small one, 2 lines by 4.

Obs. At p. 463 of his ‘ British Paleozoic Fossils,’ Prof. M‘Coy mentions that “the
magnificent suite of specimens of P. giganteus now in the University Collection enables him
to state positively that the distinctions relied on by M. de Verneuil in the ‘ Geology of
Russia,’ and M. de Koninck in his ‘Monograph of Productus, for separating P. /atis-
simus from P. giganteus, do not really exist ; several specimens in the collection showing
in one individual the gradual conoidal passage of the ear into the body of the shell (as in
P. latissimus), on the one side, and a narrow sub-cylindrical ear, projecting abruptly from
the side of the defined gibbous body of the shell (as in the P. gzganfeus), on the other :
that the other characters mentioned as distinctive by them and the‘older authors, such as
thinness of the shell, and few or no longitudinal folds, greater depression of the ears, &c.,
are characters of the young shell, and particularly the entering valve: further, both forms
(contrary to what those authors suppose) occur together in abundance in the same bed in
Northumberland.” This is not, however, the opinion of the larger number of paleon-
tologists, who cannot recognise in the peculiar spmdle shape of P. /atissimus a simple
variation in form of P. giganteus; and I must confess that the examinations I have made of
many examples of both would not enable me to arrive at so positive an opinion as that of
the distinguished author above quoted, although I would not dispute the possibility of
its being correct. At all ages and dimensions, from that of four lines in breadth to four
inches and a half, the shell appears to retain its very transverse appearance; and its
interior dispositions, although similar in character to those of giganteus, appear to
me somewhat different in their minor details, and, notwithstanding what has been asserted
by M‘Coy, the shell seems to me much thinner than that of Martin’s species.

In England, P. /atissimus is common in the limestone and shales of various localities.
Sowerby mentions that it occurs in a cherty limestone at Tyddmaur Farm, in Anglesea ; it
is not uncommon at Settle in Yorkshire, Fountains Fell, Kirby Lonsdale, in Northum-
berland, &e. In Scotland, it is one of the most characteristic species in some of the lower
stages of the Carboniferous system : it is found in Lanarkshire at two different levels ; thus
at Belston Burn it occurs at 265 fathoms below “ Ell Coal,” and 391 at Braidwood
Gill, also at Brockley, near Lesmahago; in Renfrewshire, at Arden Quarry, Thorn-
liebank ; in Ayrshire, at Roughwood and West Broadstone Beith, &c.; in Stirlingshire,
in the Craigenglen (Campsie) beds. In Ireland, it is stated by Mr. Kelly to occur
in the calciferous slate and carboniferous limestone of Lisnapaste, Killymeal, and
Raheendoran. On the Continent, it has been found at Visé in Belgium, and in several
Russian localities.

PRODUCTUS. 147

Propuctus HuMERosuS, Sow. Pl. XXXVI, figs. 1, 2.

Propuctus HuUMEROsSUS, Sow. Min. Conch., t. 322, January, 1822.
— norripus, De Koninck. Mon. du genre Productus, 1847 (not of Sow. ?)
o ACULEATUS (Schlotheim), Von Buch. Uber Productus oder Leptaena
Akademie der Wissenschaften, p. 35, 1841.

Of this Productus internal casts alone have been hitherto found, so that no description
of the exterior can be given. The length generally slightly exceeds the breadth, while
the hinge-line is usually somewhat shorter than the width of the shell. The ventral
valve was gibbous and of great thickness, with perhaps a slight longitudinal depression or
sinus ? while the dorsal one was concave, light, and thin. ‘The interior details are sharply
sculptured upon the internal casts. The ventral valve in the cast is very remarkable on
account of two large projecting ccnical protuberances situated about the middle ‘of the
shell, with their extremities directed towards the beak, and which in the enormously
thickened shell formed very deep cavities, which no doubt afforded accommodation to the
spirally coiled ? oral arms. ‘The muscular impressions form also in the cast a remarkable
protuberance, and in the shell itself occupy the rostral or incurved portion under the
cavity of the beak. The adductor or occlusor produces two radiating dendritic impressions,
longitudinally divided by a narrow ridge, and on either side there is (in the shell) a deep,
strongly grooved or striated sub-quadrate impression, which is due to the cardinal or
divaricator muscle, the remainder of the inner surface of the valve being covered with
rugosities. In the interior of the dorsal valve, the quadruple impressions of the adductor,
as well as the reniform impression, do not differ from those of the generality of Producta.
The absence of the shell itself renders specific determination uncertain, and the name is
consequently only provisionally retained. In their monographs, Baron von Buch and
Prof. L. de Koninck have placed P. dumerosus among the synonyms of the Permian P.
horridus ; and although I would not deny the possibility of this view being correct, still as
none of the internal casts of the Permian shell, that have come under my observation, have
exhibited those enormously developed and peculiar conical protuberances present in the
Carboniferous casts, and as the muscular impressions in the ventral valve differ also some-
what in their details, I have preferred (at least provisionally) retaming the denomination
under which the Carboniferous Productus is generally known.

The internal casts of P. Aumerosus are from the Magnesian Limestone of the Car-
boniferous series of Breedon in Leicestershire, and a fine series of specimens may be seen
in the Collection of the Geological Society and British Museum.

148 BRITISH CARBONIFEROUS BRACHIOPODA.

Propvuctus corsa, D’Orbigny. Pl. XXXVI, fig. 4, and Pl. XLII, fig. 9.

Propuctus cora, D’Orb. Paléontologie du Voyage dans l’Amérique Méridionale,
pl. y, fig. 8, 9, and 10, 1842.
_ COMOIDES, De Konineck. Descrip. des Anim. Fossiles du Terrain Carb. de
la Belgique, pl. xi, fig. 2%” and fig. 5” (not of Sow.), 1843.
_ corruGata, M‘Coy. Synopsis of the Carb. Limest. Fossils of Ireland,
pl. xxvi, fig. 13, 1844.
— Nerrepitvi, De Verneuil. Russia and the Oural Mountains, vol. ii,
pl. xvii, fig. 11, 1845.
— cora. De Koninck. Monographie du genre Productus, pl. iv, fig. 4, and
pl. v, fig. 2, 1847.
_ corruGata, M‘Coy. British Pal. Foss., p. 459, 1855.
— PILETFORMIS, M‘Chesney. Desc. of New Species of Fossils from the
Palzeozoic Rocks of the Western States of America, p. 40,
1859.
-- corsa, Dav. Mon. of Scottish Carb. Brach., pl. iv, fig. 13, 1860.

Spec. Char. Shell thin, longitudinally oval, or semi-cylindrical, usually longer than
wide ; hinge-line about as long as the breadth of the shell; ventral valve gibbous, evenly
convex, or slightly flattened along the middle: beak wide and incurved; ears small,
and generally crossed by four or five deep undulating folds or large wrinkles, which
extend to some distance over the lateral portions of the valves. Surface covered with
numerous longitudinal, straight or slightly flexuous, narrow, thread-like, rounded striw, with
sulci or interspaces of rather less width, while smaller strize are often intercallated between
the larger ones, the ribs being also regularly crossed by small concentric lines. Spines
few in number, sparingly scattered over the surface, but more numerous on the ears.
Dorsal valve concave, following the curves of the opposite one, and similarly ornamented.

Dimensions variable, some examples have attained or exceeded two and a half inches in
length, by three and a half in width.

Obs. This Productus is well characterised and distinguishable from its congeners
both by shape and sculpture; but the four or five large concentric wrinkles which usually
cover the ears and lateral portions of the valves are much less developed in certain
examples than in others. In the dorsal valve, the visceral portion of some specimens is
also entirely crossed by a variable number of concentric folds or wrinkles (as represented in
Pl. XLII, fig. 9), but which do not exist m the generality of specimens. ‘The shell varies
likewise very much in shape, being at times almost oval, while in other examples the
margin becomes considerably expanded. Prof. de Koninck, who has had the advantage of
being able to examine D’Orbigny’s original specimens, positively asserts that they cannot
be distinguished from the European examples we are now describing, and that consequently
Prof. M‘Coy’s P. corrugata will require to be added to the synonyms; and I believe that
my Belgian friend is likewise correct when he refers the Russian P. Neffediev’ to
1)’ Orbigny’s species.

PRODUCTUS. 149

In England, P. cora has been found in the carboniferous limestone of Kendal,
Lowick, Settle, Poolwash (Isle of Man). In Scotland, in the Mill Burn and Balgrochan
beds, as well as Campsie Main limestone, Stirlingshire ; at Arden Quarry, near Thornliebank,
in Renfrewshire; West Broadstone, near Beith, Ayrshire. In Ireland, at Larganmore,
Millecent, Milverton, Skerries, Little Island, &c. In Belgium, at Vis¢, Tournay, &c.
In Russia, at Cosatchi-Datchi, near Sterlitamak, &c. In America, it was found by
D’Orbigny in a blue compact limestone above Patapatani, in one of the islands of the lake
Titicaca, and in a gray limestone at Yarbichambi. It has been also obtained from the
Mountain Limestone of Chester, Illinois, and by Dr. Fleming and Mr. Purdon in the
Punjaub (India), &. &e.

Propuctus seMiREricuLAtTus. Pl. XLII, figs. 1—11, and Pl. XLIV, figs. 1—4.

ANOMITES SEMIRETICULATUS, Martin. Petrif. Derb., pl. xxxii, figs. 1, 2, and pl. xxxiii,
fig. 4, 1809.
-— propuctus, Martin. Ib., pl. xxii, figs. 1—3.
— Scortcus, Sow. Min. Con., pl. Ixix, fig. 3, Oct., 1814.
— Martini, Sow. Ib., pl. 317, figs. 2—4, Dec., 1821.
— ANTIQUATUS, Sow. Ib., figs. 1, 5, and 6.
concinnus, Sow. Ib., pl. 318, fig. 1, 1821.
a Martini and antiauatus, Pail. Geol. York., pl. vii, fig. 2, 1836.
_ puaiLis, Phil. Ib., pl. vil, fig. 6.
LerT@Na antiquata, Fischer. Oryct. du Gouv. de Moscou, pl. xxvi, figs. 4, 5, 1837.
— TusuLIFERA, Fischer. Ib., pl. xxvi, fig. 1 (not Deshayes).
Propuctus Martini, De Kon. Desc. des Animaux Foss. du Terrain Carb. de la Belg..
pl. vii, fig. 2, 1843.
_ Inca, D’Orb. Paléont. du Voyage dans l’Amérique Mér., pl. iv, figs. 1—3,
1844 (according to M. de Koninck).
—_ Peruviants, D’Orb. Ib., fig. 4.
-— FLEXISTRIA, M‘Coy. Synopsis of the Carb. Limest. Fossils of [reland,
pl. xvii, fig. 1, 1844?
_— SEMIRETICULATUS, De Kon. Mon. du genre Productus, pl. viii, fig. 1;
pl. ix, fig..1; pl. x, fig..1, 1847.
— — and Martini, M‘Coy, Brit. Paleeozoic Fossils, pp. 467
and 471, 1855.
- a Dav. Mon. of the Scottish Carb. Brach., pl. iv, figs.
1—5, 7, and 12, 1860.
= — Salter. Quarterly Journal of the Geol. Soe., pl. vi,
fig. 1, 1861.

Spec. Char. Very variable in shape, transversely oval, sub-cylindrical or elongated ;
hinge-line as long or somewhat shorter than the width of the shell; ventral valve gibbous
and variably vaulted, with a shallow longitudinal median sinus or depression ; auriculate
expansions moderately developed ; beak wide, incurved, usually covered with irregular, con-

150 BRITISH CARBONIFEROUS BRACHIOPODA.

centric, undulating wrinkles, larger and deeper upon the ears, while the entire surface of
the shell is ornamented by many radiating, longitudinal, rounded striz, which become more
numerous towards the margin from bifurcation and interstriation, and from which project,
at variable intervals, tubular spies of sometimes considerable length. Dorsal valve
moderately concave, following the curves of the opposite one, and similarly sculptured.
Dimensions variable, some examples having attained three mches in length, by four in
breadth.

Obs. his species has varied very much in its general shape, and I am disposed to
coincide with Prof. de Koninck, while considering P. semireticulatus, P. antiquatus, P.
Martini, P. concinnus, and, I will add, P. Scoticus, as simple variations in shape of a
single species, and for which the term semzreticulatus is here retained. I am also quite
ready to admit that, if we examine only typical examples of P. semireticulatus and P.
Martini, a certain degree of difference is perceptible, on account of the profile of the first
being simply semicircularly curved, while in the second the valves are geniculated; but
these two extreme shapes are intimately connected by insensible gradation, and indeed
very often to such an extent that it would be impossible to say to which in particular
certain specimens should be referred. In Mr. Salter’s opinion, P. costatus should also be
considered a variety of the species under description ;’ and although that learned
paleontologist may be quite correct in his supposition, I do not feel myself at present
sufficiently justified in uniting the two under a single denomination. PP. sulcatus
has, I fear, without sufficient caution been located, by myself and others, among the
synonyms of P. semireticulatus, but I am now inclined to consider it a variety of P.
costatus, for reasons which will be given hereafter. P. Scoticus, of which I have seen the
original type, appears undistinguishable from P. semireticulatus ; and several other so-
termed species must likewise be placed under the same denomination.

The width of the strize, as well as the interspaces between them, vary also according to
the specimen, two or more usually occupying the breadth of a line. The larger number
are simple, but others bifurcate here and there, and especially so on the lateral portions of
the shell ; two or more in rarer cases will also sometimes unite towards the margin so as to
form a single rib, while others are due to intercalation. Several ribs at times cluster
together so as to produce an elevation, and thus give to the frontal portion of the shell a
somewhat grooved or undulated appearance ; and this was particularly the case with the
crushed specimen from which Phillips founded his P. pugi/is, the original example being
still preserved in the author’s collection. In the species under description, the spines are
likewise often more numerous and longer in certain specimens than in others, but always
most so upon the auriculate portions of the valve, where they do not appear to have been
generally disposed in a double row, or rather to have protruded from an elevated ridge, as
in P. costatus, and its variety, P. sulcatus.

» «Quarterly Journal of the Geol. Soc.,’ vol. xvi, p. 441.

PRODUCTUS. 151

The interior need hardly be described, as the details which we have carefully drawn do
not differ materially from those already noticed in other Producta ; so that all we require
to notice is that, in the ventral valve, the adductor or occlusor muscular impressions are
situated almost on a level, or are longitudinally parallel, with the divaricator scars, and
consequently much lower in the ventral valve than in P. giganteus and some other species.
In the dorsal valve, the occlusor impressions are often beautifully sculptured, and the
cardinal process tri-lobed. ‘The ventral valve is more thickened than the dorsal one, and
possesses sometimes, though rarely, a well-defined area and fissure covered by a pseudo-
deltidium, this character being beautifully displayed upon a specimen in the British
Museum, and of which an illustration will be found in my plate. Since several
palzeontologists appear, however, desirous of maintaining the term Martini as at least a
varietal designation, and although I cannot draw any line of distinction between the two,
it may be as well to mention that figs. 6 to 11 of my Pl. XLIII represent the typical shapes
of P. Martini, while the other figures would represent P. semireticulatus. In its typical
condition, P. Martini may be distinguished by the great length and sometimes irregularity
of its anterior prolongation, the visceral portion alone being regularly arched, the shell
becoming afterwards suddenly bent downwards in an almost straight line, giving to some
specimens a peculiarly elongated and geniculated appearance, as seen in figs. 6 and 7.
The sudden bend of the ventral valve makes it sometimes, in the fossil state, liable to
fracture where the sudden bend in the valve takes place, as seen in figs. 9 and 10. The
lateral portions of the valve are likewise much dilated, while numerous spines, clustered
together, project from the auriculate portions of the valve. This is also the variety to which
Martin, in 1809, applied the specific denomination of Anomites productus ; and Sowerby’s P.
concinnus is evidently nothing more than a smaller form or synonym of the same.
Productus semireticulatus is one of the most abundant and far-spread species of the genus,
and is found in almost every locality where Carboniferous Brachiopoda occur.

In England it is found in the Carboniferous Limestone and shales of Bolland, Settle,
Kirkby Lonsdale, Coverdale, as well as in various Derbyshire localities ; at Poolwash, in
the Isle of Man; Clifton, near Bristol, &c. In Scotland, it is plentiful in Lanarkshire,
Renfrewshire, Ayrshire, Dumbartonshire, Stirlingshire, Fifeshire, Edinburgshire, Dum-
fries-shire, Peebleshire, Linlithgowshire, and Berwickshire. In Ireland, at Millecent,
Lisnapaste, ‘T'ankardstown, Tornaroan, Cookstown, &c. In Belgium, it occurs in the
lower stages of the Carboniferous Limestone of Visé, De Chokier and De Lives, near Namur,
and in various other localities, as well as in the Middle Limestone of Tournay. M. de
Koninck states he has found it likewise in the following German localities :—Crumford, at
Ratingen, Altwasser, &c. In Russia, M. de Verneuil and Count Keyserling obtained it in
several localities such as the neighbourhood of Moscou, on the Dwina, the Oka, the Pinega,
and Petschora, as well as in the Timans Mountains, near the Glacial Sea, also in the Oural
Mountains, at Sterlitamack, &c. M. de Tchihatchef found it also in the Altai Mountains.

‘Tt has also been found in Spitzbergen and Australia; in the Punjaub, and in various

152 BRITISH CARBONIFEROUS BRACHIOPODA.

American localities, such as at the Island of Quehaja, near the Lake Titicaca, at the foot of
the Bolivian Andes; at Quincy, Illinois ; Keokuk, Iowa, &c.

Propuctrus costatus, J. de C. Sow. Pl. XXXII, figs. 2—9.

Propvucta costata, J. de C. Sow. Min. Conch., pl. 560, fig. 1, May, 1827.
— suxLcatus, Sow. Ib., pl. 319, Jan., 1822.
— costata (et suLcata, Sow.), Phillips. Geol. of York., vol. ii, pl. vii, fig. 2,
1836.

— cosTELLATUS, M‘Coy. Synopsis, pl. xx, fig. 15, 1844.

— costatus, De Verneuil. Russia and the Ural Mountains, vol. ii, pl. xv,
fig. 13> 1845.

a _ De Koninck. Mon. du genre Productus, pl. viii, fig. 3, and
pl. x, fig. 3, 1847.

— — Dav. Mon. of Scottish Carb. Brach., pl. ii, figs. 22—24,
1860.

Spec. Char, Shell very variable in shape, transversely semi-cylindrical, wider than
long ; hinge-line about as long as the width of the shell. Ventral valve gibbous, very
much vaulted ; abruptly arched, or obscurely geniculated ; beak incurved, but not overlying
the hinge-line except at its attenuated extremity, a median longitudinal sinus or depres-
sion dividing the valve to a greater or less extent into two lobes; ears more or less
developed, sloping abruptly from the visceral portion, with a strong, rugged, semicircular
ridge on either side, obliquely placed to the hinge-line, and from which project several long,
cylindrical, hollow spines, similar to those situated close to the cardinal edge. Surface
covered with a variable number of strong, longitudinal rounded ribs of unequal width, and
which become more numerous towards the margin from occasional bifurcation or inter-
calation, while the whole visceral portion is crossed by numerous regular concentric wrinkles,
producing reticulate tuberculations. The spines are long, but variable in number, projecting
here and there from the ribs. Dorsal valve somewhat geniculated, following the curves of
the opposite valve, a slight median elevation corresponding to the sinus of the ventral
valve ; the visceral portion is usually somewhat flattened, while the anterior portion of the
valve becomes more or less abruptly bent upwards, the sculpture being similar to that of
the opposite valve.

Dimensions variable: a.typical specimen measured, length 18, width 23 lines.

Obs. So variable do the shells composing this species appear to be, that it is very
puzzling to know how to dispose of certain shapes which, although individually somewhat
different from the typical form, appear, nevertheless, linked to them by insensible
gradation. Sowerby states his species to be “transversely oblong, with an angular
depression in the middle; costae few, broad, decussated at their upper part, compressed
upon the deflected front, each side furnished with two or three spines and a small tube.”
This description will suit typical specimens, such as the one the author had at the time

PRODUCTUS. 153

before him, but it would scarcely be equally applicable to all the shells which compose the
species. ‘Thus, the median depression is extremely shallow, and even absent in certain
examples ; the characteristic rugged, semicircular ridge, with its strong, elongated spines,
present on typical specimens, is at times very little developed, and even absolutely wanting
in certain examples, while the number of ribs will vary from eighteen to fifty, and are
more often rounded than flattened, the spines being likewise more numerous on some
examples than on others. When publishing my monograph of Scottish Carboniferous
Brachiopoda I erroneously placed Sowerby’s P. su/catus among the synonyms of P. semi-
reticulatus, but a more attentive examination of the subject has convinced me that Phillips
was correct when, in 1836, he placed P. su/catus among the synonyms of the species under
description." M‘Coy’s P. costel/atus is evidently a synonym of P. costatus, but it is more
difficult to determine whether P. mricatus and another closely allied form from Corrieburn,
in Stirlingshire, should be considered as varieties of Sowerby’s P. cos/atus. Having
obtained the loan of the original example of P. muricafus preserved in the museum at
York (fig. 11 of my plate), I found that it was imperfect, and much more circular than the
typical and usual shapes of P. costatus ; but it presented, however, the same median depres-
sion, and although the tubular spines projecting from the convex surface of the ribs were
more numerous, still intermediate forms seemed to unite Phillips’s species to P. costatus
proper. I am therefore inclined to believe that P. muricatus is only a variety of the shell
under description, or a race peculiar to certain localities; but as I may be mistaken, and
in order to allow the subject to remain an open question, I will describe Phillips’s shell
under a separate or varietal denomination.

Var.? P. muricatus, Philips. Pl. XXXII, figs. 1O—14.

Propvcta MuriIcata, Phillips. Geol. of York., pl. vin, fig. 3.

Shell circular, about as long as wide; hinge-line somewhat shorter than the greatest
width of the shell; ventral valve regularly arched, so as to present in profile nearly a half
circle, uniformly convex, or slightly longitudinally depressed along the middle ; beak large,
wide, rounded and incurved, but not overlaying the hinge-line except at its attenuated
extremity ; ears very small; surface covered with numerous rounded ribs, of unequal width,
augmenting in number here and there by bifurcation or intercalation, while two or three
will sometimes unite into one; long, slender spines project at intervals from the ribs, and
form also a row close to the cardinal edge. Dorsal valve regularly concave and similarly
sculptured. Proportions variable. 'T'wo specimens have measured—

Length 11, width 10, greatest depth 5 lines.
ee Oe ee el 2 Be Ra:

1 As already mentioned under P. semireticulatus, Mr. Salter is inclined to consider the last-named
shell and P. costatus as varieties of a single species.

20

154 BRITISH CARBONIFEROUS BRACHIOPODA.

‘To the typical forms of this variety we have united certain specimens from Corrieburn,
of which the figs. 18 and 14 of our plate are representations; but it is desirable, at the
same time, to mention that the Corrieburn specimens are remarkable on account of the
narrowness or smallness of their ribs, none much exceeding half the width of those of
Phillips’s type; and as the general form of the shell in both, as well as the arrangement of
the spines, is similar, I have not ventured to apply to it a separate specific denomination,
although it may possibly be distinct. One of the principal differences observable in P.
muricatus lies in the ventral valve being regularly convex, and the dorsal one regularly
concave, while in all well-shaped examples of P. cosfatus the valves are generally somewhat
obscurely geniculated. ‘The interior of P. mzricatus is still unknown, but the dorsal valve
of P. costatus has been found several times, and does not differ in its details from what we
observe in other Producta.

P. costatus has been obtained from the Carboniferous limestone of several English
localities, such as Settle and Richmond, in Yorkshire; at Bolland; in the dark Car-
boniferous limestone of Lowick, Northumberland, &c. In Scotland it has been found at
Hillhead, and Brockley, in Lanarkshire; Barrhead, in Renfrewshire; Roughwood and
West Broadstone, &c. In Ireland, in the upper limestone of Old Leighlin.

Prof. de Koninck states in his ‘ Monographie’ that he has not discovered the species in
Belgium, but I possess a specimen from Visé identical in shape and character with many
of our British forms. In Russia it occurs in the Carboniferous limestone of the neigh-
bourhood of Sloboda, Government of Toula, also of Botcharova, on the Volga, &c. In
the limestone of St. Louis, in the Missouri, America, very abundant and unusually large ;
in the Punjaub, &e.

The variety P. muricatus is stated by Phillips to occur at Harelaw and Kirby Lonsdale.
In Scotland it has been found at Cessnock, and Gateside Beith, in Ayrshire, at Corrie-
burn, in Stirlingshire, and Castlecary, in Dumbartonshire.

Propvuctus Loneisrinus, Sowerby. Pl. XXXV, figs. 5—17.

ANOMI& ECHINAT& (pars),Ure. History of Rutherglen, p. 314, pl. xv, figs. 3, 4, 1793.
Propvuctus LONGISPINUS, Sow. Min. Conch., vol. i, p. 154, pl. Ixviti, fig. 1, October,
1814.
_— Fiemineii, Sow. Ib., fig. 2.
— spinosus, Sow. Ib., pl. Ixix, fig. 2, 1814.
_ LOBATUS, Sow. Ib., pl. 318, figs, 2—6, 1821.
_ ELEGANS, Davreux. Const. Geol. de la Prov. de Liege, p. 272, 1833 (ac-
cording to De Koninck).
— sETosA, Phillips. Geol. of Yorkshire, vol. ii, pl. viii, figs. 9 and 17, 1836.
a LoBaTus, V, Buch. Verhandl. der Konigl. Akad. der Wissens. zu Berlin,
aus dem jahre, Theil. i, p. 32, pl. ii, fig. 17, 1841.
— Capacil, D’Orb. Paléont. du Voyage dans l’Amérique Méridionale, pl. iii,
figs. 24—26, 1843. °

PRODUCTUS. 155

PRODUCTUS LONGISPINUS, De Koninck. Descript. des Animaux foss. du terr. Carb.
de Belgique, p. 187, pl. xii, fig. 11%” and pl, xii’,
fig. 2, 1843. P. Flemingii, Mon. du genre Productus,
pl. x, fig. 2, 1847.

— LOBATUS, De Verneuil, Russia and the Ural Mountains, vol. ii, pl. xvi,
fig. 3; pl. xviii, fig. 8, 1845.

TUBARIUS, De Keyserling. Reise in das Petschora Land, p. 208, pl. iv,
fig. 6, 1846.

— LONGISPINUS, Dav. Introduction to British Fossil Brach., pl. ix, fig. 221,
1853.

— WasasueEnsts, Norwood and Pratten. Notice of Producti in the Western
States and Territories, Journal of the Academy of Nat. Sciences
of Philadelphia, pl. i, fig. 6, 1854.

— SPLENDENS, Norwood and Pratten. Ib., pl.i, fig. 5.

— Fieminait, M‘Coy. British Paleozoic Fossils, p. 461, 1855.

— LONGISPINUS, Dav. Mon. Scottish Carb. Brach., pl. ii, figs. 10—19, 1860.

Spec. Char. Shell very variable in shape, rather small, subcylindrical, usually slightly
transverse, rarely longer than wide: hinge-line as long, or a little shorter than the greatest
width of the shell; frontal margin rounded or more or less indented. Ventral valve
gibbous, evenly convex, or more or less divided into two lobes by a longitudinal sinus of
variable depth, commencing at a short distance from the extremity of the beak; auricu-
late expansions small; beak incurved, but rarely protruding much beyond the hinge-line.
Dorsal valve moderately and uniformly concave, following the curves of the opposite valve,
or with a small mesial fold slightly developed towards thie front. Surface of each valve
covered with numerous small, longitudinal, rounded strie, tolerably regular in their course
and respective widths, but augmenting in number by occasional bifurcation and inter-
calation. Visceral portions crossed by small, concentric, undulating wrinkles, more developed
upon the auriculate expansions; long tubular spines project from some of the ribs at
irregular intervals, more numerous on the ears. Dimensions variable; two British
examples measured—

Length 9, width 10 lines.

Sco he rape eae

Oés. At least nine or ten so-termed species have been fabricated out of variations in
shape of this common, far-spread, very variable species; but as the study of the types
themselves and of a multitude of specimens has clearly shown that every variety or varia-
tion is intimately connected by intermediate gradation and inseparable links, we should not
be justified in retaining, even as varietal denominations, any of the names enumerated
among the synonyms. In Great Britain the shell does not appear to have ever attained
much larger proportions than those given above; and as the term Jongispinus is the best
known and first recorded in the ‘ Mineral Conchology,’ it is retained from the species. P.
Flemingii was badly drawn from a very imperfect specimen, nor does Sowerby’s figure even
do justice to the original specimen, which, along with P. /ongispinus and spinosus, may

156 BRITISH CARBONIFEROUS BRACHIOPODA.

still be seen in Dr. Fleming’s collection. P. spinosus is another condition or variation
of the shell under description, while P. /odafus represents those specimens in which the
median sulcus is very much developed, while every connecting link can be found in the
same bed and quarry between the evenly convex specimens and those with a deepened
median sinus, ‘The striation is sometimes very fine in some examples, coarse in others,
so that on two shells of the same dimensions fifty ribs will be counted on the ventral
valve of the one, thirty on the other; the hinge-line is also in many examples shorter
than the width of the shell, longer in others. The long, slender, tubular spines which
are scattered over its surfaces vary likewise considerably in number in different individuals,
and Sowerby was almost correct while mentioning that “two principal ones are nearly
straight and cylindrical, attached to the convex side of the convex valve, and extending in
line parallel to the hinge.” ‘These two spines are rather constant in the majority of specimens
Ihave examined, and are often seen as represented in Sowerby’s figure (5 of my plate), but
not always parallel to the hinge; the other spines are more irregularly scattered over the
surface, while some are two or even three times as long as the length of the entire valve.
Many of the most marked modifications in shape assumed by this species have been care-
fully represented in my plate, and these will suffice to show how large a range of variation
must necessarily be given so as not to violate the laws of nature. Beautifully perfect
interiors of both valves are not rare in certain localities. On the concave surface of the
ventral one two elongated contiguous dendritic adductor or occlusor impressions project at
times considerably above the level of the valve, and immediately under, but outside, of
these may be seen the two large longitudinally striated subquadrate impressions, attributa-
ble to the divaricator muscle, while a glance at my figures of this and the corresponding
valve of P. semireticulatus will show the difference in position occupied by these muscles
in the two species. ‘The occlusors in the last-named shell are almost upon a level and
longitudinally parallel with the divaricator, while in P. dongispinus the divaricators
commence only at or close to the base of the occlusors. A difference in the arrange-
ment of these muscles occurs likewise in P. punctatus, and denotes that the three species
might be distinguished alone by the details connected with their interior arrangements.
In the interior of the dorsal valve the cardinal process is proportionally large and trilobed,
under which a median longitudinal ridge extends to a little more than half the length of
the valve, and becomes much elevated and thickened towards its extremity ; on either side
may be seen a pair of dendritic scars formed by the adductor or occlusor muscle; the
reniform impressions are also well defined and often much raised, and the surface of the
valve is covered near its margin with numerous spinulose asperities ; minute canals tra-
versing the valves are also clearly visible in the shape of punctures, especially upon speci-
mens that have been slightly weathered.

In the ‘ Geology of Yorkshire,’ Prof. Phillips figures two variations in shape of the shell
under description by the name of sefosa; his fig. 9 (15 of my plate) is a large, but not
unusual, shape of P. /ongispinus, while his fig. 17 (16 of my plate) is a rarer condition of

PRODUCTUS. 157

the same shell, but of which many examples have been found in the same quarries along
with every intermediate passage form, Possessing examples of Norwood and Pratten’s
P. Wabashensis ard P. splendens, 1 could not recognise the smallest difference between
them and the generality of our Scotch examples of Sowerby’s shell, and I have but little
doubt that the list of synonyms mght be further increased had we the means of com-
paring certain so-termed species with our British forms. I consider that Prof. M‘Coy is,
however, mistaken while locating P. pugi/is, Phillips, and his own P. cos/e//atus among the
synonyms of the shell under description. In England P. lozgispinus is common in the
Carboniferous limestone and shales of several Derbyshire and Yorkshire localities, and at
Lowick, Northumberland, Poolwash, Isle of Man, &c.

In Scotland it is exceedingly abundant in various counties, and occurs in several stages.
At Braidwood, in Lanarkshire, it occurs at 337 fathoms lower than the ‘ Ell Coal,” and
a little lower again at Hallcraig, Raes Gill, Langshaw, Hillhead, Kilcadzow, &c., in the
Parish of Carluke ; also in the same county at Kersgill and Brockley, near Lesmahago,
Auchentibber, and Calderside, High Blantyre, Capel Rig, East Kilbride,’ &c. — It occurs
also in Renfrewshire, Dumbartonshire, Ayrshire, Stirlingshire, Edinburghshire, Had-
dingtonshire, Fifeshire, &c.

In Ireland it occurs in the Calciferous slate and Carboniferous limestone of many
localities, such as Lisnapaste, Howth, Ballyduff, Mohill, Hook, Bundoran, Millicent,
Culkagh, &c.

In Belgium, at Visé, Tournay, &c., and, indeed, is found in almost any Carboniferous
district where Brachiopoda have been found. In Russia, at Karova, Government of Kalouga,
&c. Yarbichambi, on the edge of the Lake Titicaca, on the Bolevian table-land of the
Andes, and Sangamon, County Illinois, in America, &c. In the Carboniferous limestone
of the Punjaub in India. Carrocreek in Tasmania, &c.

Propuctts sinuatus, De Koninch. Pl. XX XIII, figs. 8—11.

Lept@na stnuata, De Koninck. Description des Animaux fossiles du Terrain Carb. de
la Belgique. Supplément, p. 654, pl. lvi, fig. 2, 1851.
— — M‘Coy. British Paleozoic Fossils, p. 453, 1855.
Propvuctus stnvatus, Dav. The Geologist, vol. iv, p. 48, Feb., 1861.

Spec. Char, Shell transverse, longer than wide ; obscurely subtetragonal ; hinge-line
about as long as the greatest width of the shell; cardinal angles rounded. Ventral
valve geniculated from the anterior half, being bent at right angles to the posterior or
visceral portion; ears large, reflexed, curving away from the hinge-line; visceral disc
somewhat flattened, but divided by a longitudinal sinus commencing at a short distance

' In his ‘History of Rutherglen and East Kilbride,’ published in 1793, David Ure gives two figures of
the shell under description,

158 BRITISH CARBONIFEROUS BRACHIOPODA.

from the small, shghtly convex beak, and extending to the front, dividing the valve into
two convex lobes. Cardinal area well defined, subparallel and narrow, divided by a
small fissure covered by a pseudo deltidium. Surface ornamented by numerous small,
rounded, longitudinal strize, sometimes bifurcating or increasing in number by intercalation
at. various distances from the beak, and crossed by numerous small, concentric lines or
wrinkles, while about fourteen long, vertical, slender, tubular spines are arranged in two
rows close to the cardinal edge. ‘The dorsal valve follows the curves of the opposite one,
but has a mesial elevation in lieu of a sinus, and is similarly sculptured. Dimensions
variable ; length 7 inches, width 12 lines.

Obs. Of this remarkable species a few imperfect examples were discovered for the
first time by Prof. de Koninck in the Carboniferous limestone of Visé, in Belgium, and
who, misled by the well-defined ventral area, supposed his species to be referable to the
genus Leptena. Prof. de Koninck’s figures do not represent the perfect condition of the
shell, for none of his examples retained the peculiarly extended and reflexed ears which I
have drawn with great care from some very perfect specimens discovered by Mr. Burrow
in the Lower Scar limestone of Settle, in Yorkshire, and from which my description is
taken. When it so happens that, from fracture, the auriculate expansions are absent and
that the area is not exposed, some examples in this condition might be mistaken for
certain deeply sinuated specimens of P. /ongispinus, but the last-named shell is usually
more regularly vaulted and rarely geniculated to the extent observable in P. sinuatus.
Interiorly, both species differ in the position which the adductor muscular impressions in
the ventral valve occupy relative to the divaricator ones ; those in P. simvatus being longi-
tudinally parallel or on a level with the divaricators, while in P. /onyispinus the last-
named, muscular scars commence under and outside of the adductor impressions, so that
in Sowerby’s shell the four muscular scars in the ventral valve occupy a larger space than
in P. sinuatus, where they are all on a level or parallel to each other, and occupy a small
saucer-shaped space in the rostral portion of the valve. In the dorsal valve the muscular
and reniform impressions do not appear to differ much in detail from those of P. dongispinus
or of the generality of other Producta, and in any case the interior markings denote with
certainty that P. szawatus is a true Productus, and could in no case be classed with
Leptena. None of the specimens or internal casts exhibited evidence of teeth, so that it
is probable that the valves were unatticulated, as they appear to be in all known species
of the genus.

Prof. M‘Coy mentions that the shell under description is rare in the Carboniferous
limestone of Derbyshire, and it has been recently discovered at Bowertrapping, near
Dalry, Ayrshire, Scotland, and which I was happy to recognise among some duplicates
forwarded to me by Mr. Young.

PRODUCTUS. 159

Propuctus MARGARITACEUS, Phillips. Pl. XLIV, figs. 5—8.

Propucta MARGARITACEA, Phillips. Geol. of Yorksh., vol. ii, p. 215, pl. viii, fig. 8,
1836.

_ pEcTINOIDES, Phillips. Ib., pl. vu, fig. 11.

— MARGARITACEUS, De Kon. Desc. des Anim. foss. du Terr. Carb. de Belgique,
pl. vii, fig. 3; pl. viii’, fig. 5, 1843. Mon. du genre
Productus, pl. iv, fig. 3, 1847.

— _ De Keyserling. Wissensch. Beobacht. auf einer Reise in
das Petschora Land., p. 210, pl. iv, fig. 7, 1846.

- — M‘Coy. British Paleeozoic Fossils, p. 466, 1855.

Spec. Char. Shell thin, somewhat circular or transversely semicircular, rarely longer
than wide ; hinge-line rather less than the width of the shell. Ventral valve regularly
convex, without sinus; beak small, incurved ; ears narrow and but slightly distinguishable
from the general convexity of the valve; surface ornamented with numerous thick,
obtusely rounded or flattened ribs, separated by shallow sulci, the costz often bifurcating
near the margin, while the whole surface is closely crossed by concentric imbricating
striz, which at intervals produce strongly marked foliaceous interruptions or lines of
growth. ‘The spines are few in number, but four or five strong ones project from each
of the auriculate expansions, while two or three more are sometimes irregularly scattered
over the surface. Dorsal valve concave, following the curves of the ventral one, and
similarly ornamented. Interior details imperfectly known. Dimensions variable; two
British examples have measured—

Length 15, width 18 lines.
pte Lier EO},

Obs. This is a well-marked species, easily distinguishable from its congeners, both by
shape and sculpture. Its shell is likewise remarkably thin and delicate, the ears very
brittle and often broken, while the space occupied by the animal between the valves is
very small. In shape it is more often transverse, and to this variety the name margaritacea
had been applied, while to the rarer or elongated form that of pectinoides was given ; but
as every gradation in shape between the two can be readily found, a single specific
denomination can alone be retained.

P. margaritaceus does not appear to be a very common species, and is confined to the
middle and lower stages of the Carboniferous system. In England it occurs at Bolland,
Kendal, Settle, in Yorkshire, as well as in some Derbyshire localities, &c. In Ireland it
may be obtained at Florence-court, Millecent, Kildare. Mr. Kelly mentions also
Lisnapaste, Bundoran, and one or two more places where it is said to occur.

On the Continent it is not abundant in the Carboniferous limestone of Visé and Tournay
in Belgium, and has been found at Ratingen, D’Altwasser, in Silesia, and in one or two
Russian localities.

160 BRITISH CARBONIFEROUS BRACHIOPODA.

Propuctus arcuarius, De Koninck. Pl. XXXIV, fig. 17.

Propuctus ARcuaARiuS, De Kon. Descript. du Animaux foss. du terrain Carb. de la
Belgique, p. 171, pl. xii, fig. 10° 1843, and Mon. du
genre Productus, pl. iv, fig. 2.

Spec. Char. Shell small, transversely oval ; hinge-line much shorter than the greatest
width of the shell. Ventral valve almost hemispherical and regularly vaulted up to a
certain distance or age, when it is again continued under the shape of a wide, prominent
border, separated from the rostral half by a groove, which, originating on either side of the
beak, curves round the valve. The margin is also sometimes bent up at right angles, and
thus forms a flattened rim all round the shell. Beak and auricular expansions small.
Surface ornamented by numerous radiating, thread-like striae, which become more numerous
by interstriation, and are here and there swollen out, giving rise to a variable number of
slender, tubulated spines, which are more numerous on the ear-shaped expansions. Dorsal
valve concave, following the curves of the ventral one, and similarly ornamented. Interior
unknown. Dimensions variable ; a British example measured—length 53, width 8 lines.

Obs. ‘This little shell does not appear very rare in the Carboniferous limestone of
Settle, in Yorkshire, where it was discovered for the first time in Britain by Mr. Burrow.
Having submitted specimens to Prof. de Koninck, he declared them to be specifically
identical with those from Visé, in Belgium. 'The concentric groove which divides the
ventral valve into two portions is not, however, always so distinctly marked in the British
specimens that have come under my observation as in certain Belgian individuals figured
by Prof. de Koninck.

Propuctus carBonarius, De Koninck. PI. XXXIV, fig. 6.

PropucTus CARBONARIUS, De Honinck. Deserip. des Animaux foss. der terr. Carb.
de la Belgique, pl. xi fig. 1, 1843, and Mon. du genre
Productus, pl. x, fig. 4, 1847.

— — De Vernewil. Russia and Ouval Mountains, pl. xvi, fig. 2,
1845.
-- — Dav. A Mon. of the Carb. Brachiopoda of Scotland, pl. iv,

fig. 14, 1860.

Spec. Char. Shell of median size, about as wide as long, or slightly transverse ;
ventral valve very gibbous, evenly rounded, and without sinus ; auriculate expansions small ;
hinge-line nearly as wide as the greatest width of the shell. Surface ornamented with very
fine, thread-like, radiating striz, from which project at short intervals numerous slender
spines, the rib becoming thickened at the spot where the spine originates ; beak small,
much ineurved, and covered with a few slight concentric wrinkles. Dorsal valve following

PRODUCTUS. 161

the curves of the opposite one, and similarly ornamented. Interior unknown. A British
specimen measured—length 93, width 11, lines.

Ods. Lam acquainted with but a single British example of this species, stated to have
been found in Carboniferous limestone north of Glasgow (?) and now preserved in
the museum of Practical Geology. The identification is given on the authority of
Prof. de Koninck, and it would be very desirable that more specimens should be obtained
and examined before its specific claims be definitely recognised. Our Scottish example
agrees, however, very nearly with the figure published by Prof. de Koninck of a specimen
found in a calcareous nodule at Chokier, in Belgium, and M. de Verneuil states he has ob-
tained the species in a Carboniferous limestone in the valley of Prikcha (Valdai), Russia.

Propuctus unpatus, Defrance. Pl. XXXIV, figs. 7—13.

Propuctus unpatus, Defrance. Dic. des Se. nat., vol. xliu, p. 354, 1826.

— — De Koninck. Desc. des Animaux foss. du Terrain Carb. de
Belgique, p. 156, pl. xii, fig. 2, 1843; and Mon. du genre
Productus, pl. v, fig. 3.

— TORTILIS, M‘Coy. Synopsis of the Carb. Foss. of Ireland, tab. xx, fig. 14, 1844.

— unpatus, De Vernewil. Russia and the Ural Mountains, vol. ii, p. 261,
pl. xv, fig. 15, 1843.

— — Dav. Mon. Scottish Carb. Brach., p. 41, pl. iv, figs. 15—17,
1860.

Spec. Char. Shell somewhat sub-orbicular or slightly transverse ; hinge-line rather less
than the width of the shell. Ventral valve regularly vaulted, very convex, without sinus ;
beak small, rounded, incurved, not extending much beyond the hinge-line ; auriculate ex-
pansions small. Surface covered with numerous irregular or interrupted sub-parallel, un-
dulating, concentric folds or wrinkles, which become wider and more produced with age,
and having their narrow, almost perpendicular, side directed towards the beak ; the valve is,
moreover, ornamented by numerous minute, rounded, thread-lke strize, separated by narrow
sulci, and of which from five to six may be counted in the thickness of a line, and
swelling out at intervals, they give rise to aslender spine. Dorsal valve concave, following
the curves of the opposite one, and similarly ornamented. Interior unknown. Dimensions
variable ; two British examples have measured—

Length 14, width 13, lines.
“08 delat leon to ila age | eae

Ods. ‘This remarkable species, although not common, is by no means very rare in the
Carboniferous limestone of Great Britain, and may be easily distinguished from other
British Producta by that curious terrace-shaped or crumpled-like appearance it presents,
and which is caused by the numerous concentric wrinkles which cover the surface of both

21

162 BRITISH CARBONIFEROUS BRACHIOPODA.

valves. In some specimens these ridges are very regular and uninterruptedly continuous,
but in the larger number of individuals some of them are here and there interrupted in
their course and absorbed, while two at other times unite during their passage along
the middle. The radiating thread-like striae bear much resemblance to those of P. Cora,
and increase in number here and there by interstriation.

In England, 2. wadatus occurs in the lower scar limestone of Settle, in York-
shire, in the lower Carboniferous limestone of Lowick, Northumberland, middle limestone
of Poolwash, Isle of Man, and upper Carboniferous limestone of Derbyshire. In Scotland,
it occurs in limestone at Gare and Headsmuir, at about 240 fathoms below the
horizon of the “ Ell Coal.” In Stirlingshire, in the Campsie main limestone, and at
Castlecarry, in Dumbartonshire. In Iveland, at Tullynagaigy, Fermanaugh, and at Little
Island, near Cork.

On the Continent, it occurs in the limestone of Visé, in Belgium, and at D’Unja, near
Kosimof, as well as at Nikoulin and Karova, in Russia. M. de Koninck mentions also
that a specimen is preserved in the Museum of Paris, found in Tasmania.

Propuctus Wricuti, Dav. Pl. XXXII, figs. 6, 7.

Spec. Char. Shell small, transversely oval; hinge-line rather less than the width of
the shell. Ventral valve convex and regularly vaulted; beak and auriculate expansions
small. Surface covered with numerous smooth, regular or irregularly interrupted, undulating,
concentric folds or wrinkles, from which, at short intervals, project scattered spines; the
margin of the valve is, moreover, bent up at right angles, forming a wide, flattened, but
ribbed boarder or frill round the shell. Dorsal valve and interior unknown. The largest
specimen hitherto discovered measures—length 35, width 5 lines, of which the bent-up
margin is from 1 to 13 line in width.

Obs. Of this interesting little species two examples were discovered by Mr. J. Wright
in the Carboniferous limestone of Middleton, near Cork, in Ireland, and have been considered
by Prof. de Koninck, as well as by myself, a new species (?) The concentric folds or wrinkles
resemble much those of P. wadafus in their terrace-like arrangement, but are dis-
tinguished by the total absence of those longitudinal, thread-like striz so beautifully
disposed in Defrance’s species; the wide fringe or frill which surrounds the shell is also
peculiar.

The species is named after Mr. Joseph Wright, to whom the author of this monograph
is indebted for much valuable material and information relative to the species from
the neighbourhood of Cork, in Ireland.

PRODUCTUS. 163

Propuctus proposcipEus, De Vernewil. PI. XXXII, figs. i—4.

Propuctus PproposcipEus, De Verneuil. Bulletin de la Soc. Geol. de France, vol. xi,
p. 259, pl. iii, fig. 3, 1840.

CLAVAGELLA PRISCA, Goldfuss. Petref. Germ., vol. ii, p. 285, pl. clx, fig. 17, 1841.

Propuctus PpRoBoscIDEUS, V. Buch. Abhand. der. K. Akad. der Wissens. zu Berlin,
Erster Theil., p. 40, 1841.

— — De Koninck. Descript. des Animaux foss. du Terrain Carb.

de Belgique, p. 11, fig. 4, 1843; and Mon. du genre
Productus, pl. vi, fig. 4%%%4% 1847.

Spec. Char. Shell of moderate size, and very variable in shape, on account of the
singular prolongation of its ventral valve. Dorsal valve small, gently and regularly concave ;
slightly transverse or elongated, with a straight hinge-line always shorter than the greatest
width of the shell. Surface covered with fine, radiating, thread-like strize, intersected
by numerous concentric wrinkles. ‘The ventral valve is composed of two well-marked
parts ; the first (which corresponds with almost the entire dorsal valve) is marginally
somewhat circular, moderately convex, and about as wide as long, the beak being very
small and but slightly incurved over the hinge-line of the opposite valve. Auriculate
expansions small. ‘lhe second portion is composed of a general prolongation of the
margin of the same valve, which commences by the lateral portions extending on either
side, and, by gradually forcing open the smaller valve, unite round its margin, to be pro-
longed afterwards in the shape of a cylindrical tube of lesser or greater length. his
tube is concentrically wrinkled, and irregular in width and direction, while the surface of
the entire valve is minutely striated, and numerous long, slender spines rise and project
forwards from the lateral expansions of the ventral valve. Interior unknown. Pro-
portions very variable ; two British examples have measured

Ventral valve, entire length, with tube, 135, width 5, lines.
Dorsal valve = be Ae 53.) Ae eer

Another example measured—

Ventral valve, entire length, with tube, 11, width 43, lines.
Dorsal valve ~ i Se | | eee

Obs. ‘This Productus is one of the most remarkable of the genus, and its discovery
by Mr. Burrow in the Carboniferous limestone of Settle, in Yorkshire, was the more
interesting from the fact that authentic examples of the species had not until then been
found in any other locality than Visé, in Belgium.’ The shell has been fully described and

! Another form, (?) nearly related by shape to that under description, has been described and figured by
Messrs. Norwood and Pratten from the Carboniferous rocks of Graysville, Illinois, America, under the
denomination of P. clavus, but which is stated by these paleontologists to “differ from P. proboscideus,
with which alone it can be confounded, in the longitudinal ribs not extending over the visceral portion,
and injthe prolongation not showing the numerous and well-marked transverse folds of that species. The

164 BRITISH CARBONIFEROUS BRACHIOPODA.

illustrated by Messrs. de Verneuil and de Koninck, who state that, although the tube was
generally simple, it sometimes bifurcated, and then two independent tubes were pro-
duced. Its direction is generally that of the longitudinal axis of the shell, but it is often
irregularly twisted to the one or the other side, and may likewise remain straight for
some time before suddenly bending and assuming another direction, as represented in one
of the specimens figured in my plate. ‘The tube has also attained at times considerable
length, one Belgian example figured by Prof. de Koninck being nearly two inches in
length, with not more than four Imes in width, and although the specimen was broken
and imperfect at its extremity, the width had not altered in allitslength. M. de Koninck
has also observed that he has never been able to procure a single specimen in which the
tube was complete, and therefore concludes that its extremity was open, and served for the
passage of muscular fibres, by which the animal attached itself to submarine objects.
But, as I have already had occasion to observe at p. 119 of my “ General Introduction,” I
feel compelled to differ with my learned friend in this last assumption. M. d’Orbigny
believed the prolongation to be due to malformation produced by accidental circumstances,
connected with the supposed constrained position in which the animal lived, which forced
the mantle to prolong its edges so as to reach the surface of the sea-bed; but in the
localities in which the form is found a vast number of other species of the genus occur,
which do not present this peculiarity, so that we must regard the structure as normal,
although M. d’Orbigny’s explanation of its function is probably correct ; and in any case
I cannot concur in the supposition that the shell may have been fixed to submarine bodies
by the means of muscular fibres issuing from the open extremity of the tube. ‘The pro-
longation of the ventral valve beyond that of the dorsal one is not a feature peculiar
to the shell under consideration, for it has been noticed already in two or three more
species of the same genus, as well as in a Liassic form of Thecidium, where the ventral
valve is prolonged much beyond that of the dorsal one.

The two parts of which the ventral valve is composed are clearly defined by the means
of a groove.

Propuctus Ermingus, De Koninch. P|. XX XIII, fig. 5.

Propuctus prmMingtus, De Koninck. Descript. des Anim. foss. du Terr. Carb. de
Belgique, p. 181, pl. x, fig. 5, 1843; and Mon. du genre
Productus, pl. vi, fig. 5, and pl. xviii, fig. 1.

Spec. Char.+ Shell of moderate dimensions, longer than wide; hinge-line much

longitudinal ribs of P. proboscideus are also much finer, numbering about fifty in the space of ten mille-
metres at the interior border of the visceral part. P. clavus shows no trace of sinus.’ It must, however,
be remembered that the American specimen is stated to have been in so imperfect a state of preservation
that for some time the authors hesitated in including it in their memoir, and it is still possible that
P. clavus may, after all, belong to M. de Verneuil’s curious species (?).

PRODUCTUS. 165

shorter than the greatest width of the shell. Ventral valve gently convex from the extremity
of the beak to the front, the lateral portions being much extended and bent downwards
at almost right angles to the plane of the valve; beak and auriculate expansions small,
witn a ridge commencing at their extremity, extending to some distance on either side,
thus dividing the visceral from the labial extensions of the valve. The surface is covered
with numerous thread-like, radiating striae, which increase in number by interstriation at
various distances from the beak, from which project a few scattered spines; it is also
ornamented by many concentric, undulating wrinkles, which become larger or wider as
they recede from the extremity of the beak. The dorsal valve is concave, following closely
the curves of the opposite one, and is similarly ornamented. Interior like that of
other Producta. A British example measured—

Length 10, width 93, lines.

Obés. ‘This species differs from P. prodboscideus, by its dorsal valve following exactly
the curves of the ventral one, and by the last-named valve not being prolonged in the
form of a cylindrical tube. It occurs in the Carboniferous limestone of Settle, in York-
shire, where it was found for the first time in England by Mr. Burrow, and is there
associated with P. prodoscideus, as well as at Visé, in Belgium, the only two localities in
which the species has been hitherto discovered.

Propuctus tEssELLATUS, De Koninck. Pl. XXXIII, figs. 24, 25; Pl. XXXIV,
fig. 14.

Propucius mMuRicatTus, De Koninck. Descript. des Animaux foss. du Terr. Carb.
de Belgique, p. 192, pl. ix, fig. 2; pl. 13>s fig. 5 (not
Phillips), 1843.
PropuctUs TESSELLATUS, De Koninck. Monographie du genre Productus, Mémoires
de la Soc. Royale des Sciences de Liege, vol. iv, pl. xiv,
fig. 2, 1847.
— — Morris. Catalogue, p. 145, 1854.

Spec. Char. Shell small, transversely oval, a little wider than long; hinge-line
much shorter than the width of the shell. Ventral valve evenly convex and regularly
vaulted, without sinus; beak small, prominent, and incurved, not projecting beyond the
hinge-lme; auriculate expansions very slightly developed. Surface ornamented by from
fifteen to twenty round, salient costs, from which project a few scattered spines, and inter-
sected by about as many concentric grooves; margin bent upwards, wide, flat, or slightly
concave, and marked by numerous rounded, bifurcated, or trifurcated ribs, with dorsal
valve gently concave, and ornamented as in the ventral one. Interior unknown. Dimensions
variable ; two British examples have measured—

Length 11, width 12, lines.

ij @¥OF xvas ey! 51

166 BRITISH CARBONIFEROUS BRACHIOPODA.

The flattened border is nearly one third of the entire length of the valve.

Obs. This elegant shell appears rare in British Carbomiferous rocks, but is easily
distinguished from other forms of the genus by shape and sculpture, as well as by the
flattened, ribbed border which encircles the valves. In England it has been found by Mr.
Burrow in the Calcareous limestone of Settle, in Yorkshire, by the Rev. 'T. G. Cumming
in the Isle of Man, while in Ireland it occurs in the Calcareous limestone of Kildare.
On the Continent it is not very common at Visé, in Belgium.

Propuctus acuLuatus, Martin. Pl. XXXIII, figs. 16—20.

ANOMITES ACULEATUS, Martin. Petrif. Derbiensis, p. 8, pl. xxxvii, figs. 9, 10, 1809,
(not Schlotheim).
Propuctus acuLEatus, Sow. Min. Con., tab. Ixviii, fig. 4, Oct., 1814.
Propucta LAXxisptNna, Phillips. Geol. of York., pl. vin, fig. 13, 1836.
Propuctus spinuLosa, Phillips. Ib., vol. ii, pl. vii, fig. 14 (not of Sow.), 1836.
— GRYPHOIDES, De Koninck. Desc. des Anim. foss. du Terrain Carb. de la
Belgique, pl. ix, fig. 1, and pl. xii, fig. 12, 1843 (?)
— ACULEATUS, De Koninck. Mon. du genre Productus, pl. xvi, fig. 6, 1847.
— — M‘Coy. British Paleozoic Fossils, p. 458, 1855.
— — Dav. Mon. of Scottish Carb. Brach., pl. ii, fig. 20, 1860.

Spec. Char. Shell of moderate dimensions, ovate or semicircular, slightly transverse
or elongated ; hinge-line less than the width of the shell. Ventral valve regularly vaulted,
gibbous, without sinus; beak much incurved and overlying the hinge-line at its attenuated
extremity ; auriculate expansions small and thin. Surface in the young shell covered with
a variable number of irregularly scattered, elongated tubercules, from which project small,
curved spines, but with age the tubercules are at times so close and elongated on the
anterior half of the valve that they become transformed into longitudinal ribs ; the surface
is moreover intersected by regular or undulating laminar, concentric lmes. Dorsal valve
very concave, following closely the curves of the opposite one, and similarly ornamented.
Interior unknown. Dimensions variable; three British examples have measured—

Length 6, width 63, lines (Martin’s type).

rl i ras
Sry Sea els a

Obs. In general appearance this Productus varies considerably, according to age and
specimen, Martin’s type (of which I have given a carefully enlarged representation) having
been described and drawn from a young shell, which was almost smooth, from the very few,
irregularly scattered, tubular spines which covered its surface ;* but in other specimens, with

! Martin describes his species—‘A fossil shell. Original an dzomia, imperforate, with one of the
valves concave, the other convex and gibbous. Hinge close, straight, but less extended than in most
other Anomite of the same division (Syst. G. B., ‘Anomitee,’ 6,6). The convex valve prickly; the

—ESSS

PRODUCTUS. 167

age the tubercules became closer and closer, until converted into ribs, the posterior half of the
valves usually preserving the characters of the young shell. Martin describes the spines as
pointed backwards towards the beak, but this observation has already been shown by Prof.
de Koninck and M‘Coy to have been erroneous, their direction being similar to that of
other Producta. P. daxispina of Phillips has been drawn from a large example of
Martin’s species, and the P. spénulosa, Phillips (but not of Sow.), would appear to be like-
wise referable to the same species.

P. aculeatus is a common shell in many localities. In England, it occurs in Carboniferous
limestone at Bakewell, Buxton, and Chrome Hill, Longnor, in Derbyshire; at Settle, in
Yorkshire; Bolland, in Westmoreland ; Lowick, Northumberland ; in the middle limestone
of Poolwash, Isle of Man, &c. In Scotland, at Calderside ; High Blantyre, in Lanarkshire ;
Orchard Quarry, Thornliebank, Renfrewshire; at West Broadstone, Beith, in Ayrshire ;
as well as at Craigie, near Kilmarnock, and Auchenskey, near Dalry, in the same county.
In Ireland, in limestone at Lisnapaste, Howth, Old Leighlin, Little Island, and Windmill.

On the Continent, it occurs at Visé, in Belgium. In Russia it has been found in several
localities, such as in the neighbourhood of Buregi, Government of Nowgorod, as well as
at Cosatchi-Datchi, on the Oriental side of the Oural, to the east of Minsk, &c.

Propuctus Younaianus, Dav. Pl. XXXIII, figs. 21—23.

Propuctus Youneranus, Dav. Mon. of Scottish Carb. Brach., pl. ui, fig. 26, and
pl. v, fig. 7, 1861.

Spec. Char. Shell longitudinally oval ; hinge-line shorter than the width of the shell.
Ventral valve regularly arched, convex, and without sinus; auriculate expansions very
small; beak incurved and comparatively large, not overlying the hinge-line except quite
at its attenuated extremity. Dorsal valve very concave, following closely the curves of the
opposite one. Surface in both valves ornamented with numerous small, rounded ribs, of
which a certain number are due to intercalation, and from which, at short distances,
project slender, tubular spines, more widely scattered in some specimens than in others ;
the valves are also covered with irregular, undulating, squamiform, concentric expansions,
which overlap each other very numerously in some examples, sparingly in others. In the
interior the muscular and reniform expansions are similar to those of other Producta.
Dimensions variable ; two British examples have measured—

Length 13, width 9, lines.

ee

Oés. This shell appears distinguishable from P. aculeatus by its more regularly oval

prickles few, scattered, very minute, short, appressed, or squeezed flat to the surface, and pointing back-

wards or towards the beak. The beak small and hooked. . . . . . . It is found near Bakewell
and Buxton.’’

168 BRITISH CARBONIFEROUS BRACHIOPODA.

and elongated appearance, its mbs being likewise more numerous and regular, both in
the young and adult condition, than what is usually observable in Martin’s species. In
this opinion I am supported by Pref. de Koninck and Mr. Young, but am still some-
what uncertain whether the shell under description is in reality more than a variety of
Martin’s_ species.

In Scotland, P. Youngianus occurs abundantly in a white friable shale above a
coralline bed (Zzthodendron fasciculatum, Fleming, Lithostrotion Martini, M. Edwards).
It is found also at Brockley, near Lesmahago, in Lanarkshire, as well as in Renfrew-
shire, Ayrshire, and Fifeshire.

In England in Carboniferous limestone at Llangollen, in Wales.

Propuctus pustuLosus, Phillips. Pl. XLI, figs. 1—6; Pl. XLIL, figs. 1—4.

PYXIS TRANSVERSIM STRIATA, Chemnitz. Martini’s Neues Syst. Conch. Cabinet,
vol. vii, p. 301, pl. lxiii, figs. 605 and 606, and
vol. viil, fig. 69, 1784.
Propucta pusTULOsA, Phillips. Geol. of Yorks., vol. ii, p. vii, fig. 15, 1836.
— RUGATA, Phillips. Ib., fig. 16.
— ovaLis, Phillips. Ib., pl. viii, fig. 14.
Propuctus .pusTuLosus, De Koninck. Desc. des Anim. foss. du Terr. Carb. de
Belgique, pl. xii” fig. 3, 1843.
= PUNCTATUS, Kon. (non Martin). Ib., pl. ix, fig. 6.
— PusTuLOsuS, Kon. Mon. du genre Productus, pl. xiii, fig. 1, and pl. xvi,
figs. 8, 9, 1847.
— PYXIDIFORMIS, Kon. Ib., pl. xi, fig. 7; pl. xii, fig. 1; pl. xvi, fig. 2.

Spec. Char. Shell thin, rotundato-quadrate, wider than long, rarely oval and longer
than wide; hinge-line shorter than the greatest width of the shell. Ventral valve regu-
larly arched and gibbous, divided longitudinally by a sinus of greater or lesser depth and
width; beak moderately developed and incurved, not overlymg the hinge-line except at
its attenuated extremity; ears wide, nearly rectangular, and flattened; margin slightly
indented in front. External sculpture varying somewhat in appearance in different speci-
mens, but usually covered with numerous continuous or interrupted transverse, undulating
wrinkles, while numerous pustules or elongated tubercules, bearing slender, tubular spines,
are subquincuncially arranged or disposed in irregular rows over the entire surface. Dorsal
valve slightly concave, with a small mesial elevation or fold, while numerous transverse
wrinkles, tubercule-pits, and short spines, cover the surface. Dimensions variable ; three
examples measured—

Length 44, width 46, greatest depth between valves 17, lines.

2) 28, 39 39, 23 22 3? 10, 29
oP) 24, 2? 20, 29 ? 29 8, 9

Obs. After a lengthened comparison and study of more than one hundred specimens

PRODUCTUS. 169

of the shell under description, there can exist but little doubt that P. rugata, P. ovalis, and
P. pyexidiformis, are merely different states of P. pustvlosus, and I quite comeide with
Professor M‘Coy when stating that “scarcely any two examples of P. pus/v/osus agree in
the strength or directness of the transverse ridges ; in specimens perfectly typical in this
respect near the beak, the ridges will be often found indistinct, undulated, and mterrupted
on other parts, and when this is the case the tubercules generally increase im size and be-
come quincuncially arranged. I have traced the passage from the most regularly wrinkled
type (like Koninck’s figure, op. cit., t. xii, fig. 4), with the spines on the summits of the trans-
verse ridges, through those in which the spines do not comeide with the (still well-marked)
ridges (like his t. xvi, fig. 9), to those in which the wrinkles gradually become irregular,
interrupted, and nearly obsolete, as in P. pyaidiformis, by the most imperceptible gradations.
In all these varieties the isolation of the tubercules, instead of their being mere inflations of
distinct, longitudinal striz or ridges, distinguishes the species from the true P. scabricula.”
I have never yet obtained a perfect specimen of the shell under description, for im all
the British examples the spines were broken close to their base.

The interior has been sometimes obtained, and of which figures ave given in my plate.
In the umbonal portion of the ventral valve the occlusor or adductor scars are placed on
either side of a small ridge between and on a level with the cardinal or divaricator im-
pressions. In the dorsal valve the adductor and riniform impressions do not differ much
in detail from what we find in the generality of Producta. P. pustulosus is not rare mn
the Carboniferous limestone of many English localities, such as Bolland, Settle, Kendal,
the Isle of Man, in Derbyshire, &c. In Scotland it has been stated to occur at Cat Craig,
near Dunbar. In Ireland in the Calciferous slate and Carboniferous limestone of
Bundoran, Ballyduff, Carrigaline, Lisnapaste, Millecent, Tankardstown, Florence Court,
Little Island, shores of Lough Gill, valley of the Maine, Hook, St. Doolas, near Dublin, &c.

On the Continent it occurs at Visé and Tournay, &c., in Belgium ; Ratingen (Prussia) ;
and it has also been found im America.

Propucrus scasricuLus, Martin. Pl. XLII, figs. 5—S.

ANOMITES SCABRICULUS, Martin. Petrif. Derb., p. 8, pl. xxxvi, fig. 5, 1809.
PropuctTUsS — Sow. Min. Conch., t. Ixix, fig. 1, Oct., 1814.
Propucta scaBRicuLa, Phill. Geol. of York., vol. ii, pl. vil, fig. 2, 1836.
— quincuncraLis, Phill. Ib., pl. vii, fig. 8.
—_ SCABRICULUS, De Koninck. Desc. des Anim. foss. du Terrain Carb. de Belg.,
pl. xi, fig. 3” (?), 1843; and Mon. dugenre Productus, pl. xi,
fig. 6, 1847.
— corsIs, Potiez et Michaud. Galer. des Mollusques du Mus. de Douai, vol. ii,
pl. xh, fig. 2, 1844.
— SCABRICULUS, De Verneuil. Russia and the Ural Mount., pl. xvi, fig. 5; and
pl. xvili, fig. 5, 1845.
— — M‘Coy, British Pal. Fossils, p. 470, 1855.
_ — Dav. Scottish Carb. Brach., pl. iv, fig. 18, 1861.

22

170 BRITISH CARBONIFEROUS BRACHIOPODA.

Spee. Char. Marginally rotundato-quadrate, generally wider than long, lateral margins
sub-parallel ; rounded or slightly mdented in front ; hinge-line rather less than the greatest
width of the shell. Ventral valve convex, with a wide, shallow, median depression or
sinus ; beak incurved, not overlyimg the hinge-line, except at its attenuated extremity ;
ears small, flattened. Surface covered with numerous sub-regular striz, swelling out at close
intervals in the shape of oblong tubercules, arranged somewhat irregularly in quincunx, and
from each of which rise slender, curved spines, of rather less than half an inch in length ;
feeble concentric wrinkles sometimes traverse the valve, and are especially marked on the
ears. Dorsal valve concave, near the margin, with a slight median elevation commencing not
far from the front ; surface covered with numerous concentric wrinkles, tubercule-pits, and
short, depressed, slender spines. Dimensions variable ; two British examples measured—

Length 285, width 333 lines.

eng Me eered sn wee:

Obs. Variations in shape of this shell have received different names, and it has been
sometimes suggested that it and the preceding species should be united.’ Professor de
Koninck mentions that it bears much resemblance with the young state of his P. pyzxidi-
Jormis, and that it approaches likewise to P. Humboldt, and I am ready to admit that a

3?

certain external resemblance does sometimes exist among certain examples of these species.
In true P. scabriculus the swollen-out, alternating, elongated tubercules are connected by
a continued ridge, so that the shell has the appearance of being ribbed, while in P. pustu-
Josus the tubercules are more often isolated. The interior, however, in the dorsal valve
presents a difference in the shape of the median ridge, which extends from under the
cardinal process and divides the adductor impression. In P. pustulosus this ridge is
simple, while in P. scabriculus it is composed of two ridges, which converge and unite at
some distance from their origin into a single ridge (fig. 8). I have observed this character
in several examples, and believe it constant.

P. scabriculus is common in the Carboniferous limestone of the Craven district, and
Settle, in Yorkshire; near Bolland; in dark Carboniferous limestone at Lowick,
Northumberland; Martin found it in the limestone of Tideswell, in Derbyshire. It is not
uncommon at Coalbrook Dale; near Bristol, &e. In Scotland, it is plentiful in ironstone
at Jock’s Burn, Braidwood, Brockley, and many other Lanarkshire localities. In Stirling-
shire it occurs in several stages, such as the Craigenglen beds, Campsie main-limestone
and ironstone, and at Corrieburn. It has also been found in Renfrewshire, Dumbarton-
shire, Ayrshire, the Lothians, and Fifeshire. In Ireland, Mr. Kelly mentions that it occurs
in the Calciferous slate and Carboniferous limestone of Lisnapaste, Millecent, Little Island,
and of, no doubt, many other localities. It is also a common fossil on the Continent,
having been found at Visé, in Belgium; Peredki (Valdai), Sloboda, &c., in Russia.
Specimens have also been collected in America, &c.

1 Explanations to accompany sheets 102 and 112 of the maps of the Geological Survey of Ireland,
p. 16.

PRODUCTUS. il

Propuctus rrpriatus, J. de C. Sowerby. P). XXXII, figs. 12—15, and Pl. XLIV, fig. 15.

ANnomites punctatus, Martin. Petrif. Derb., pl. xxxvii, figs. 7, 8 (fig. 6 exclusa), 1809.
Propuctus rimsBriatus, J. de C. Sow. Min. Conch., pl. 459, fig. 1, July, 1823.
STROPHOMENA MaRSUPIT, Davreux. Const. Geogn. de la province de Liege, pl. iv, fig. 2 a, B,
1833.
Propucta rimBriata, Phillips. Geol. of York., vol. ii, pl. vill, figs. 11, 12, 1836.
— V. Buch. Abhandl. der K. Akad. der Wissens. zu Berlin, Theil i,
p. 27, pl. ii, figs. 21—23, 1841.
_ — De Koninck. Desc. des Animaux foss. du Terr. Carb. de Belgique,
pl. x, fig. 3 ©%°%4 1843; and Mon. du genre Productus, pl. xii,
fig. 3 © 4% 1847.
?Propucta Laciniata, M‘Coy. Synopsis of the Carboniferous Fossils of Ireland, pl. xx,
fig. 12, 1844.
Propucta rimBriata, M‘Coy. British Paleozoic Fossils, p. 461, 1855.
— — Dav. Mon. of Scottish Carb. Brach., pl. ii, fig. 27, 1860.

Spec. Char. Longitudinally oval or ovate ; hinge-line a little shorter than the width of
the shell. Ventral valve uniformly convex, gibbous, and greatly arched in profile ; beak
much incurved, overlying the hinge-line at its attenuated extremity ; ears small and but
slightly marked. Surface regularly traversed by numerous sub-regular, concentric, promi-
nent bands or ridges, with flattened, intervening spaces ; a row of elongated tubercules cover-
ing each ridge, and from which project long, tubular, cylindrical spines. Dorsal valve
nearly flat or moderately concave, traversed by numerous concentric ridges, with concave
interspaces ; a row of short, adpressed spines projecting from every ridge. Dimensions
variable ; two specimens have measured—

Length 18, width 17, greatest depth between valves 9 lines.

AS EES 2 3 53 sup mane

Obs. This species does not attain the proportions of P. punctatus, is less variable
in its shapes, possesses no sinus, and is especially distinguished by the single row of
cylindrical spines which rise from each row of elongated tubercules, as above de-
scribed. With P. laciniata, M‘Coy (Pl. XLIV, fig. 15), I am not sufficiently
acquainted. It has been supposed by some a synonym of P. punctatus, but the study
of two Irish examples leads me almost to agree with M‘Coy while stating that it bears
more resemblance to P. fimbriatus, of which it is possibly only a variety or variation
in shape, more transverse, with a greater number of concentric ridges, smaller and more
numerous elongated tubercules or cylindrical spines.’ This I must, however, leave as an open
question for the present. The interior of the dorsal valve of P. fimbriatus alone is at present

1 At p. 110 of the ‘Synopsis,’ M‘Coy describes his P. /aciniata as “nearly semicircular, length one
sixth less than the width; hinge-line rather less than the width of the shell; moderately convex ; beak
small, prominent; ten or twelve rounded, concentric wrinkles, fringed on their marginal declivity with
close, regular, lengthened spine-bases. Length eleven lines; width one inch one line.” Fig. 15 of our
44th plate is taken from the original specimen.

172 BRITISH CARBONIFEROUS BRACHIOPODA.

known, and appears to present certain peculiarities which have been carefully represented in
the figures of my plate. Thus, the adductor muscular impressions are very much produced,
and form two pairs of contiguous projections, separated by a short median ridge which extends
to nearly the centre of the valve, where it becomes much elevated, with a depression or pit on
either side, margined by a vertical wall, as in Strophomena analoga and some other species.
The reniform impressions are also much more oblique in their direction than is usual to the
species of this genus. In the greater number of specimens the spiniferous ridges are
separated by almost smooth spaces, but in some rarer examples the tubercules or spine-
bases are so much elongated as to give the surface somewhat the appearance of certain
examples of P. scabriculus.

P. fimbriatus is not uncommon in the Carboniferous limestone of Derbyshire, of Lowick,
Northumberland ; limestone and shale of Settle, in Yorkshire; Bolland; Poolwash, Isle
of Man, &c. In Scotland at Hillhead, at Middleholm, Lanarkshire; Gateside and West
Broadstone Beith, Ayrshire; in Fifeshire, &c. In Ireland, at Little Island, Bundoran,
Tornaroan, &c. In Belgium it is common in the lower stage of the Carboniferous system
of Visé, rare in that of Chockier; and has been found also at Sterlitamak, in Russia, &c.

Propuctus puncratus, Martin. Pl. XLIV, figs. 9—16.

ANoMITES PuNCTATUS, Martin. Petrif. Derb., pl. xxxvii, fig. 6 (7, 8 exclusa), 1809.
Triconia RUGOSA, Parkinson. Organ. Remains, vol. ii, pl. xii, fig. 11, 1811.
ANOMITES THECARIUS, Schloth. Nachtr. zur Petrefactenk, pl. xiv, fig. 1, 1822.
Propuctus PuNcTATUS, J. Sow. Min. Conch., t. 323, Jan., 1822.
Propvucta PuNcTatTA, Phillips. Geol. of York., vol. ii, pl. viii, fig. 10, 1836.
Lepr@na sutcata, Fischer. Oryct. du Gouy. de Moscou, pl. xxiii, fig. 2 (non Sow.), 1837.
Propuctus punctatus, 7. Buch. Abhandi. der K. Akad. der Wissens. zu Berlin, Thiel. i,
pl. ii, figs. 10, 11, 1841.
— a De Kon. Desc. des Animaux foss. du Terr. Carb. de Beigique,
pl. viii, fig. 4; pl. x, fig. 2; pl. ix, fig. 4, 1843; and Mon. du
genre Productus, pl. xi, fig. 2, 1847.
— CONCENTRICUS, Potiez et Michaud. Galer. des Mollusques du Mus. de Douai,
vol. ii, p. 25, pl. xli, fig. 1, 1844.
— punctatus, De Vern. Russia and the Ural Mountains, vol. 11, pl. xvi, fig. 11,
1845.
— TuBULOsPINA, M‘Chesney? Desc. of New Species of Fossils from the Palzeozoic
Rocks of the Western States, p. 37, 1859.
— punctatus, Dav. Scottish Carb. Mon., pl. iv, fig. 20, 1860.

Spec. Char. Shell thin, variable in shape ; transversely rotundato-quadrate, or slightly
elongated oval; hinge-line shorter than the width of the shell. Ventral valve convex,
sometimes gibbous, with a shallow, longitudinal, mesial depression or sinus, commencing at
a short distance from the extremity of the beak and extending to the front ; beak incurved,
overlying the hinge-line at its attenuated extremity ; ears flattened, but slightly defined.

PRODUCTUS. 173

Surface covered with numerous sub-regular, concentric bands or ridges, which increase in
number and breadth as they recede from the extremity of the beak, but in adult shells
becoming again closer as they approach the margin; these bands (in the ventral valve) are
slightly raised towards their lower margin, and are abruptly separated from each other by
a narrow, smooth space, after which there exists a tolerably regular row of lengthened
tubercules or slender, shining, tubular spines, and again below these the remaining space is
filled up by irregularly scattered, but closely packed, smaller spines, all overlapping one
another, and lying close to the valve. Dorsal valve moderately concave, with a slight
mesial elevation, and ornamented as in the dorsal one, but the bands are slightly concave.
In the interior of the ventral valve the adductor or occlusor muscular impressions extend
much lower down in the shell than do those attributable to the divaricators. In the
dorsal valve the muscular and reniform impressions differ but slightly from those of other
Producta. ‘I'wo specimens have measured—

Length 28, width 31, greatest depth between valves 12 lines.

PZ seep 2at 3 ' sptclellg:..3

Obs. This common and very characteristic species appears to have been described and
figured for the first time by David Ure, who mentions that “ both valves are covered with
small spines resembling hair, and so numerous that a largish example contains upwards of
ten thousand, and lie so closely together that the surface of the shell is entirely concealed
from view,” but it is rare to find the specimens in that condition, the valves being usually
deprived of their spiny investment. Martin appears, however, to have been the first
naturalist who applied to the shell a specific denomination, but he confounded under the
same name the P. fimbriatus of Sowerby, a closely allied, but easily distinguishable species.

Productus elegans has been generally considered a synonym or a young condition of the
shell under description; but as I am still uncertain whether it be really so or a distinct
species, as believed by M‘Coy, it will therefore be preferable to describe it separately, but,
perhaps, as a variety of P. punctatus, to which it bears much resemblance in the arrange-
ment of its spines. P. punctatus is characterised in all well-shaped examples by a median
depression or sinus, but as this commences usually at a short distance from the extremity
of the beak it has been supposed, correctly or erroneously, that in the young state the ventral
valve may have been convex and without sinus (?).

Var? uiucans, M‘Coy. Pi. XLIV, fig. 15.

Propuctus ELEGANS, M‘Coy. Synopsis Carb. Foss. Ireland, pl. xviii, fig. 13, 1844; and
British Paleozoic Fossils, p. 460, pl. iii u, fig. 4.

Shell rather small, longitudinally ovate; hinge-line a little shorter than the width of
the valve. Ventral valve regularly arched and gibbous, without sinus. Surface crossed

1 «History of Rutherglen and East Kilbride,’ pl. xv, fig. 1, 1793.

174 BRITISH CARBONIFEROUS BRACHIOPODA.

by from ten to sixteen regular broad, sub-equal, transverse ridges, obtusely angulated in
the middle, each having three or four rows of spines disposed exactly as in P. puactatus proper.
Dorsal valve slightly concave, and ornamented as in the opposite one. Length 8, width 7
lines.

Professor M‘Coy states, in his work on the Paleozoic fossils, that “ this species is inter-
mediate in all its characters between P. punctata and P. fimbriata, but is perfectly distinct
from both as a species. It agrees with the former in the zmerous, instead of single rows of
spinules on each concentric band, while it differs from it, and agrees with P. jimbriata
in the elongato-ovate form, absence of mesial furrow, and very great gibbosity of the ventral
valve, differing, however, from it in the smaller size, greater number of concentric bands in
a given space at the same distance from the beak, and in having several rows of minute
punctures, instead of a sizg/e row of elongate tubercules on each band.”

Both P. punctatus and P. elegans occur in many of the same localities. In England
they are abundant in almost every locality where Carboniferous Brachiopoda have been
found, such as in Derbyshire ; abundantly also in the Craven district ; near Bolland ; in shale
and limestone at Settle, m Yorkshire; in dark Carboniferous limestone at Lowick,
Northumberland ; at Kendal, Westmoreland ; Poolwash and Ronaldsway, Isle of Man, &c.
In Scotland it occurs abundantly in the Carboniferous limestone and shale of Lanark-
shire, Renfrewshire, Ayrshire, Buteshire, Dumbartonshire, Stirlingshire, Haddingtonshire,
and Fifeshire. In Ireland, in Calciferous slate and limestone at Lisnapaste, Millecent,
Tankardstown, Bruckless, Cornacarrow, &c. On the Continent of Europe it is also com-
mon at Visé, Lives, Namur, &c., in Belgium; in the valley of Prikcha, at Kosatchi-Datchi,
&c., in Russia. In America it abounds im several localities, such as Zanesville (Ohio),
Eddyville (Kentucky), and in coal measures throughout the western states, &c.

Propuctus Kryseriineianus, De Kon. Pl. XXXIV, figs. 15, 16.

PRopuctTUs ACULEATUS, De Koninck. Descrip. des Anim. foss. du Terrain Carb. de Bel-
gique, pl. x, fig. 8 “4° (not Martin), 1843.
—_— KEYSERLINGIANUS, De Koninck. Mon. du genre Productus, pl. xiv, fig. 6 a—d,
1847.
— — M‘Coy, British Carb. Foss., p. 466, 1855.

Spec. Char. Shell small, subrectangular, or rotundato-quadrate ; hinge-line slightly
exceeding the average breadth of the shell. Ventral valve very gibbous, sometimes rather
geniculated, and feebly depressed along the middle; beak small, and not overlymg the
hinge-line except at its attenuated extremity; ears small, slightly produced, and well
defined. Surface traversed by numerous concentric lines of growth, as well as by a few
wrinkles on the ears; a variable number of comparatively large spine-tubercles being like-
wise arranged somewhat in quincunx over the visceral portion of the valve. Dorsal valve

PRODUCTUS. 17:

Or

very slightly concave, traversed by small wrinkles and minute concentric lines of growth,
a few elongated tubercule-pits being also irregularly scattered over the visceral portion of
the valve. Length 5, breadth 6, greatest depth between the valves 2 lines.

Oés. As observed by Prof. de Koninck, this species is distinguished from P. aculeatus
by its smaller dimensions, more transverse shape, slight median depression, and lesser
concavity of its smaller valve. The spiny tubercules are not scattered over the entire surface
of the ventral valve, as in Martin’s species, but are restricted to the visceral portion of the
valve. ‘The interior is very similar to that of other Producta. P. Keyserlingianus is not a
rare fossil in the Carboniferous limestone of Settle, in Yorkshire, but much less so in that
of Derbyshire. I am not acquainted with any specimens from either Scotland or Ireland.

On the Continent it occurs at Visé, in Belgium, as well as at Likwin, Government of
Kalouga, and of Cosatchi-Datchi, Ural.

Propvctus spinuLosus, J. Sowerby. Pl. XXXIV, figs. 18S—21.

Propuctus spinuLosus, J. Sow. Min. Conch., pl. Ixvili, fig. 3, Oct., 1814.
Propucta GRANULOSA, Phillips. Geol. of Yorks., pl. vii, fig. 15, 1836.
— CANCRIN1, De Kon. Desc. des Anim. foss. du Terrain Carb. de Belgique, pl. ix,
fig. 3 (not of De Verneuil), 1843.
— paprittatus, De Kon. Ib., pl. x, fig. 6.
— GRANULOsUS, De Kon. Mon. du genre Productus, pl. xvi, fig. 7, 1847.
— — M‘Coy. British Paleozoic Fossils, p. 472, 1855.
— — Dav. Scottish Carb. Brach., pl. iv, figs. 22—24, 1861.

Spec. Char. Shell transversely semicular; hinge-line a little shorter than the greatest
width of the shell. Ventral valve regularly convex and evenly arched, without sinus ;
beak incurved, but not overlying the hinge-line, except at its attenuated extremity; ears
flattened, with a few concentric wrinkles; surface covered with sub-regular, small, slightly
elongated tubercules, irregularly or quincuncially arranged, each tubercule producing a
slender spine. The tubercules are more often about half a line or so apart near the middle
of the shell, but closer as they approach the beak. Dorsal valve deeply and evenly concave,
and covered with small tubercule-pits, arranged somewhat in quincunx. Interior
unknown. Length 7, width 9 lines.

Obs. This species does not appear to have attained proportions very much larger
than those above recorded, and is easily distinguished from all other British Producta by
shape and sculpture. To those examples in which the tubercules or spines were regularly
arranged in quincunx the term sp2nu/osus has been applied, while to those in which the spines
or tubercules were less regularly disposed the term granulosus was given. I quite coincide,
however, in the opinion expressed by Prof. M‘Coy, that the two are simply different
conditions of the same species, and should be therefore united. Prof. M‘Coy is also of
opinion that P. Koninckianus, De Verneuil, is distinct, and it is probable that P. spiau-

176 BRITISH CARBONIFEROUS BRACHIOPODA.

losus, De Koninck (but not of Sow.), is likewise a different species, for in addition to the
tubercules, the shell is represented as bemg finely longitudinally striated, a character never
observable in the many British examples of P. spcnulosus, Sow., and P. granulosus, Phillips,
that have come under my observation. I have never yet seen a well-preserved exterior of
the smaller valve, but believe it to have possessed spines. In England P. spinu/osus occurs
in the Carboniferous limestone of Bolland ; Settle, in Yorkshire ; the Isle of Man, and in
several Derbyshire localities. In Scotland it has been collected at Nellfield and Hillhead
at 375 fathoms below “Ell Coal; occurs likewise at Brockley, near Lesmahago, in
Lanarkshire. In Ayrshire, at West Broadstone and Auchenskeigh, near Dalry. At Cat-
Craig, near Dunbar, &c. In Ireland Mr. Kelly mentions Knockinny, Killukin, Millecent,
and I possess a specimen from Little Island, near Cork, for which I am indebted to Mr.
J. Wright. On the Continent it occurs at Visé, in Belgium, and has been found in
Russia.

Propuctus pricatiuis, J. Sow. Pl. XXXI, figs. 3—5.

PropuctTuUS PLICATILIS, J. Sowerby. Min. Conch., pl. 459, fig. 2, July, 1823.
aa = Phillips. Geol. of York., vol. ii, pl. viii, fig. 4, 1836.
LEpT@Na PoLyMoRPHA, Muenster. Verzeichniss der in der Kreis-Natur. Samml. zu Bayr.
befindl. Petref., p. 45, 1840 (according to Prof. de Koninck).
Propuctws pLicatitis, De Kon. Desc. des Anim. foss. du Terr. Carb. de Belgique, pl. xi,
fig. 7, 1843 ; and Monographie du genre Productus, pl. v, fig. 6,
1836.
— = M‘Coy. British Pal. Foss., p. 168, 1855.

Spec. Char. Shell thin, transversely oblong, slightly indented in front; hinge-line
about as long as the greatest width of the shell; ventral valve gibbous, and more or less
geniculated ; the visceral disc 1s semicircular and very slightly convex, while the anterior
prolongation is abruptly arched; a median depression or sinus commences likewise at
a short distance from the beak and extends to the front. Beak small, not overlying the
hinge-line; ears flattened. Exteriorly, the visceral disc or posterior half of the valve
is traversed by numerous regular or irregular, undulating, concentric wrinkles, while the
entire surface is covered with fine, thread-like, longitudinal striz. Spines long, slender, few
in number, and rising here and there from the surface of the valve. Dorsal valve
concave, with a small mesial elevation or fold towards the front. Sculpture similar to that
of the opposite valve. Dimensions variable ; two examples have measured—

Length 16, width 23, greatest depth between valves 7 lines.

pF OOS HE eas; ’ Una Bs

Obs. his Productus is well distinguished from its congeners both by shape and
sculpture. It bears some slight resemblance to Strophomena analoga, but (as justly
observed by Profrs. de Koninck and M‘Coy) does not possess the area of the last-named
species, and its interior details are those of Prodwctus, as may be seen by a glance at fig. 5

PRODUCTUS. 17

~

of our plate, which represents an internal cast of the ventral valve, on which the adductor
and divaricator impressions are well marked. ‘The interior of the dorsal valve does not
appear to have been hitherto discovered, at least no example has come under my observa-
tion. From P. swb-devis the form under description is distinguished by its transverse
shape and much smaller dimensions, &c.

In England it is found in the Carboniferous limestone of Settle, in Yorkshire; the
gray or lower limestone of Longnor and Castleton, in Derbyshire. In Ireland Mr.
Kelly mentions that it occurs in the limestone of Armagh, Salmon, and Little Island. No
specimen from Scotland has been hitherto produced, but it is very common in the
limestone of Visé, in Belgium, as well as in the dark limestone of Hof, in Bavaria, and
Falkenberg, in Silesia. It has also been stated to occur in Russia, but was not met
with there by the authors of the ‘'Travels in Russia and Ural.’

Propucius suB-Lavis, De Koninck. Pl. XXXI, figs. 1,2; Pl. XXXII, fig. 1; and
Pl. Tob ies. 2:

Propuctus suB-L.v1Is, De Koninck. Descript. des Anim. foss. du Terr. Carb. de Belgique,
pl. x, fig. 1, 1843.
STROPHOMENA ANTIQUATA, Potiez et Mich. Galer. des Moll. de Douai, vol. ii, pl. xlii, fig. 5-
1844 (according to De Koninck).
PRopUCTUS sUB-LEVIS, De Keyserling. Reise in das Petschora Land, pl. v, figs. 3 and 3%,
1846.
— Curistrant, De Koninck. Monographie du genre Productus, pl. xvii, fig. 3,
1847.

Spec. Char, Shell elongated oval, sub-quadrangular, and longer than wide; hinge-line
about as long as the greatest width of the shell. Ventral valve gibbous, much vaulted
upon itself at the beak, and longitudinally divided by a median groove or ridge, which
commences to appear at a short distance from the beak, and extends to the front,
while the lateral portions of the valve are more or less deeply furrowed ; ears moderately
developed, sub-cylindrically coiled, and sharply defined from the body of the shell by a row
of tubular spines. Externally the visceral portion of the valve is traversed by numerous
concentric, feebly marked wrinkles, while the entire surface is longitudinally and finely
striated. Dorsal valve concave, following the curves of the opposite valve, and similarly
sculptured. Interior unknown. Dimensions variable; two British examples have
measured—

Length 4 inches 8 lines, width 4 inches | line.

et ee OLN a: me con ee LOL:

Oés. ‘This remarkable Productus varies much in appearance, according to age and
specimen. When the external coat or surface is well preserved, it is very finely striated, as
well as crossed by many concentric lines of growth, but when the outer surface has been

removed by fossilisation the shell appears to be almost entirely smooth. Some examples
23

178 BRITISH CARBONIFEROUS BRACHIOPODA.

are likewise more deeply longitudinally grooved than are others, while in the ventral valve
of certain examples there exists a median depression, which in others is converted into a
projecting ridge.

It has appeared to me, after the attentive examination of about a dozen specimens,
that Prof. de Koninck’s P. sub-/evis and P. Christiani are only different conditions of a
same and single species, and should therefore be united. In England P. sub-/evis occurs
in the Carboniferous limestone of Clitheroe, in Lancashire, where it has been several times
obtained by Mr. J. Parker, Curator of the Manchester Museum. It has also been stated
to have been found in Wales, but no other British locality than that above given has
been correctly ascertained. On the Continent it has been found by M. de Koninck in the
Carboniferous limestone of Visé, in Belgium, and of Glageon, near Avesnes, in France,
and appears to have sometimes attained rather large dimensions, although nowhere hitherto
found in any profusion.

Propuctus musoLosus, Phillips. Pl. XXXI, figs. 6—9.

Propucta MESOLOBA, Phillips. Geol. of Yorks., vol. ii, pl. vii, figs. 12, 13, 1836.
Propuctus MesoLosBus, De Kon. Desc. des Anim. foss. du Terr. Carb. de Belgique, pl. xii,
fig. 8, 1843; and Monographie du genre Productus, pl. xvii,
fig. 2, 1847.
— — De Verneuil. Russia and the Ural Mount., vol. ii, pl. xvi, fig. 8,
1845.
— — M‘Coy. British Pal. Fossils, p. 468, 1855.
— — Dav. Mon. of Scottish Carb. Brach., pl. xxi, 1861.

Spec. Char. Shell thin, transversely oblong, and generally rather wider than long ;
hinge-line as long, and sometimes longer, than the average width of the shell; ears or
cardinal extremities wide, and at times much extended. Ventral valve gibbous at the
beak, and somewhat geniculated towards the front, with a wide, flattened, or slightly con-
cave sinus, interrupted in the middle by a narrow median rib, and on either side of the
sinus a rib is present, while another intervenes between these and the cardinal angles.
The beak is proportionately large, and not overlying the hinge-line, except quite at its
attenuated extremity. Exteriorly the visceral dise is covered with numerous concentric
wrinkles, and a few tubular spines project from the five ribs. Dorsal valve concave, with
a narrow median groove and two slightly marked lateral ones, while the surface is covered
with concentric wrinkles and lines of growth. Interior unknown. Dimensions variable ;
three British examples have measured—

Length 11, width 19 lines.

y Abn to lice! ae
be Gis TR ad ag
Obs. Some foreign specimens have exceeded the proportions here given, and although

CHONETES. L79

possessing some of the characters of both P. plicatilis and P. sub-levis, can always be dis-
tinguished by its narrow median ridge, deeper sinus, and lateral ribs.

In England it is found in the Carboniferous limestone of Settle, in Yorkshire, the dark
limestone of Kendal, Poolwash, Isle of Man, as well as in the gray limestone of Derby-
shire. In Scotland it has been found at 375 fathoms below ‘“ Ell Coal.” At Braidwood,
in Lanarkshire, also at Brockley, near Lesmahago; in Stirlingshire, in the Glarat lime
works, or Campsie main limestone. In Ireland at Cornacarrow, Millecent, Little Island.
On the Continent it occurs in the limestone of Visé and Tournay, in Belgium. In Russia,
at Ilinsk, on the 'Tchusovaya, Ural Mountains.

Sub-genus—Cnonutes, Mscher.'

We have already alluded to the close relationship which exists between Chonefes and
Productus, and must now refer to the great difficulties in the way of a correct and definite
determination of its species, which appears to have been unnecessarily multiplied, and at
times been fabricated out of undeterminable or uncharacterised specimens or fragments.
The confusion in which I found the species was so great that all my many efforts, consul-
tations, and researches, have proved ineffectual to satisfactorily solve the difficulty with
reference to some few of Prof. M‘Coy’s Irish so-termed species; but in order that the
reader may form his own opinion, or be better enabled to continue the research, I have
given figures of all the uncertain species (?), and, when desirable, reproduced the original
descriptions. I have not been able to determine satisfactorily more than five or six species,
viz.—1. Chonetes comoides ; 2. C. papilionacea; 3. P. Dalmaniana; 4. C. Hardrensis ;
5. C. Buchiana ; and 6. C. polita. Those termed C. laguessiana, De Kon., C. papyracea,
C. crassistria, C. tuberculata, C. sub-minima, C. gibberula, C. sulcata, C. volva, C. perlata,
and C. serrata, M‘Coy, may still demand further research, although I have myself but little
doubt that the whole number are merely different conditions or synonyms of some of the
five or six species above recorded ; and even out of this number I do not feel entirely confi-
dent with reference to C. Dalmaniana. In his monograph of the sub-genus Chonefes,
Prof. de Koninck states that “the slight difference which exists between the form and
the exterior sculpture of the various species renders their classification much more difficult
than that of Produetus, and that he has taken as basis for his arrangement the number and

Prof. M‘Coy considers Chonetes to be simply a sub-genus of Leptcena, removing it, as well as
Strophalosia (King) and dAulosteges (Helmersen), from the family Propuctip& (‘British Pal. Foss., Cam-
bridge Museum,’ p. 211), and placing them as a sub-genus among his Orthiside ; but this view appears
to me far from correct, as I have endeavoured to demonstrate in p- 112 of my ‘General Introduction,’ when
showing that the reniform impressions are the same in Chonetes as in Productus, while a completely
different arrangement prevails among the Strophomenide, of which Leptena constitutes only a section.

180 BRITISH CARBONIFEROUS BRACHIOPODA.

nature of the longitudinal ribs which ornament the surface of all the species, with the excep-
tion of a single one, wherein these are replaced by concentric plaits.” In Great Britain this
last-named shell has not been hitherto discovered, but another, which is entirely smooth,
has been obtained, so that the British species can be divided into two groups, which we wil!
distinguish as follows, and to which we have added the probable synonyms.

C. comoides, Sowerby.
C. papilionacea, Phillips = C. multidentata, M‘Coy = C. papyracea, M‘Coy?
2? C. Dalmaniana, De Koninck.

STRIATH. ‘ a) he :
C. Hardrensis, Phillips = C. sub-minima = C. gibberula = C. suleata ? = C. volva?

= C. perlata ? M‘Coy = C. laguessiana? De Koninck.
C. Buchiana, De Konineck = C. crassistria, M‘Coy.
Laves. C. polita, M‘Coy.
Uncertain species? C. tuberculata and C. serrata, M‘Coy.

Although my distinguished friend has considered the arrangement, the number, and
nature of the longitudinal striz as the best means or character to be used in the discrimi-
nation of the species, I have not always found them sufficient, on account of the extraordinary
variability in this particular which almost every specimen has presented not only at different
stages of growth, but in shells of similar dimensions, and I believe that we will find the
interior details in each of the species to be somewhat different, and a character of greater im-
portance even than that of the exterior, as may be noticed in those of which we have been
so fortunate as to procure specimens ; and, indeed, in so difficult a matter every point, both
exterior and interior, will require to be carefully examined and compared before a correct
determination can be arrived at, and surely the difficulty will be great indeed, and even
insurmountable, in those cases where the so-termed species have been fabricated from a
crushed or imperfect fragment of a single valve !

CuonrrEs comorpus. Pl. XLV, fig. 7 (1 to 6°).

Propvuctus Comorpus, J. Sow. Min. Conch., pl. 329, April, 1516.

CHONEtES —— De Keyserling. Reise in das Petschora-land, pl. vi, fig. 1,
1846.

= — De Koninck. Monographie du genre Chionetes, pl. xix, fig. 1,
1847.

—_ — Dav. Quarterly Journal of the Geol. Soe., vol. x, pl. viii, fig. 1,
and 2—8? 1853.

Spec. Char. Shell large, transversely semicircular, concavo-convex ; hinge line straight,
as long or a little shorter than the greatest width of the shell; valves strongly articulated
by the means of teeth and sockets. Ventral valve convex, beak more or less developed and
incurved, but not overlying the cardinal edge. Dorsal valve concave, following the curves
of the other. Each valve is provided with a subparallel area of greater or lesser width, but

CHONETES. 181

always narrower in the smaller valve. In the middle of this last there exists a
produced, trilobed, cardinal process, which enters and almost fills a corresponding
triangular fissure in the ventral area, and which was probably partly covered or arched
over by a pseudo-deltidium. The external surface of the shell is finely striated. In the
interior of the greatly thickened ventral valve, and under the extremity of the beak, at
the base of the fissure between the projecting teeth, originates a large, deep, pyriform mus-
cular cavity, extending to beyond half the length of the valve, and occupying upwards of a
third of its inner surface, its greatest breadth being towards the centre of the shell. In
this depression are situated four elongated muscular impressions, and these are separated
toa greater or lesser extent by three longitudinal ridges, the central one of which is shorter
than the others, and assumes the character of a mesial septum; the two smaller scars,
situated on either side near the central ridge, are due to the adductor, the outer and larger
ones to the cardinal or divaricator muscles, the muscular scars not being equally deep in
every example. Of the interior of the dorsal valve nothing is at present known. Dimen-
sions variable ; two British specimens have measured—
Length 2 inches 73 lines, width 3 inches 10 lines.
3 a he Og dsc urea

> bP)

Obs. Sowerby’s specimens of this remarkable species are incomplete, and his descrip-
tions and illustrations consequently so, but he did not fail to mention that the shell is
“very thick and rough within,” this allusion having reference to the ventral valve only
for, as I have elsewhere shown, the convex valve was often four or five times as thick as the
concave or dorsal one. Sowerby’s figures do not show the fissure which exists in the area
of the ventral valve, nor do they exhibit the area of the dorsal one, which is so well dis-
played in a specimen preserved in the Bristol Institution Museum (Pl. XLV, fig. 7).
No spines could be detected on any of the few examples that have come under my
observation, although some small circular holes could be perceived here and there, close to
the cardinal edge, in one of the specimens; but it must likewise be remembered that the
cardinal spines were very small in some other species of Chonetes, and especially so in the
large C. papilionacea, and may, consequently, uot have existed, or been destroyed, on the
few fossil examples we possess.

It has been questioned whether the shell under description should be located with
Chonetes or with Productus, and that we are not acquainted with the interior of the
smaller and most important valve ; still the area in both, and the strongly articulated
hinge, would be an anomaly in Productus, which, on the contrary, is the constant character
of Chonetes, and this alone would, at least provisionally, induce me to leave C. ? comoides
in the last-named sub-genus. It has also been doubted whether the shells, fig. 1—6 of my
Pl. XLV, do really belong to Sowerby’s species; and here, again, I must repeat what I
said in 1853, viz., “that I do not feel convinced that sufficient grounds exist for the
establishing of two distinct species (an opinion in which I was then supported by Messrs.
Salter and Woodward), the original type not appearing to us to differ materially in its

182 3RITISH CARBONIFEROUS BRACHIOPODA.

convexity from several of those represented in my plate.” ‘The area, I am ready to admit,
is certainly wider in both Mr. Sowerby’s specimens than in those belonging to Mr.
Ormerod (figs. 1—6), but the area generally varies much in its width in specimens of a
same species, as I have already often had occasion to notice. Mr. Sowerby’s second
example (not figured in the ‘Min. Conch.’) is an incomplete interior of the ventral valve,
in which, from the shell bemg young and shallow, the muscular impressions could not be
as deep or as imdented as in adult, very convex and thickened valves, such as is the
original specimen figured in the ‘ Mineral Conchology,’ or those illustrated in my plate
(figs. 3, 4); nor could I perceive that the interior of Sowerby’s specimen varied in any
essential particular from those more perfect examples I had examined. In any case, fig. 7
must be regarded as the typical shape of C. comoides, of which the other specimens figured
by me are probably variations.

Chonetes comoides does not appear to be a very common species, and all the speci-
mens hitherto procured are from the Carboniferous limestone. It has been found in
England and in Ireland in the following localities:—Llangaveni and Beaumaris, in
Anglesea; Llanymynech and Tidenham Chase, in Gloucestershire; Chepstow, T'reflach
Wood, south-west of Oswestry; Bundoran, County Donegal; and Lough Erne,
Fermanagh. On the Continent it appears to be equally rare; Prof. de Koninck
mentions having found a single specimen at Visé, in Belgium, and that he possesses
another example from Sablé, in France; that Count Keyserling has found it in the
Carboniferous limestone at the banks’ of the River Ylytsch, in the Ural, and that the
Museum of St. Petersburgh possesses examples from the neighbourhood of Switschei, a
village on the banks of the Ugra, in the Government of Kaluga, in Russia.

CHONETES PAPILIONACEA, Phillips. Pl. XLVI, figs. 3—6.

PECTINITES FLABELLIFORMIS, Lister. Hist. Conch., lib., iii, pl. 475, fig. 31, 1688.
SPIRIFERA PAPILIONACEA, Phillips. Geol. of York., vol. ii, pl. ii, fig. 6, 1836.
CHONETES PAPILIONACEA, De Koninck. Description des Anim. foss. du Terr. Carb. de
Belgique, pl. xiii, fig. 5, and pl. xiii’, fig. 1, 1843; and
Monog. du genre Chonetes, pl. xix, fig. 2, 1847.
— MULTIDENTATA, M‘Coy. Synopsis of the Char. of the Carb. Fossils of
Ireland, pl. xx, fig. 8, 1844.
— papyRacea, M‘Coy? Ibid., pl. xx, fig. 2.

Spec. Char. Shell thin, sometimes rather large, transversely semicircular, depressed,
slightly concavo-convex, but almost flat when young. Hinge-line straight, and as long as
the width of the shell. Ventral valve slightly convex at the beak, but much flattened at
the sides, and especially so near the cardinal edge; beak small, and not protruding beyond
the cardinal edge; dorsal valve very gently concave along the middle, lateral portions
much flattened; a well-defined area is present in each valve, the ventral one, which is
the widest, being divided in the middle by a triangular fissure, partially arched over by

CHONETES. 183

a pseudo-deltidium, the cardinal process of the opposite valve filling up the remaining
open space. Surface of both valves covered with numerous fine, thread-like, straight or
flexuous striae, which become more numerous by means of bifurcation and interstriation
at variable distances from the beak and umbo, the stria and interspaces being closely
crossed by numerous fine, concentric lines of growth, which produce a beautifully crenu-
lated appearance. Small spines rise from the strie at variable distances, and a row of
from twenty to thirty short ones project from the cardinal edge. Valves strongly articu-
lated by means of teeth and sockets. Interior details imperfectly known. Dimensions
variable ; two British examples have measured—

Length 2 inches, breadth 5 inches 3 lines, greatest width between the valves 3 lines.

ae ees iens tas 12s % ls»

Oés. ‘This is perhaps the largest and most beautiful species of the sub-genus
hitherto discovered, and is remarkable on account of its elegant shape and sculpture.
C. comoides is the only species with which the shell under description might be compared,
but from which it can be distinguished without much difficulty, C. comoides being a
much more ponderous and gibbous shell, and whose beak appears to be generally more
rounded and produced than is that of C. papilionacea. Although it received the very
appropriate name of papzlionacea from Phillips in 1836, it had been figured and shortly
described by Lister in 1688 —“ Pectinites flabelliformis tuberculoso commissura seu
pectinites semicircularis compresso minuta ad modum striatus.”

C. multidentata, M‘Coy, of which I have been able to examine the original specimen, is
evidently a synonym of the shell under description, and I am inclined to believe that the
fragment figured and described by the same author under the denomination of C. papyracea
is also another synonym. In England C. papilionacea has been found in the Carboniferous
limestone of Bolland, Otterburn, Kendal, Settle, Ronalds Way, Isle of Man, and
Dalton, in Furness, Lancashire, &c. In Ireland at St. John’s Point, Ballybodonnel,
Dunkineely ; Cheeverstown, County Dublin, &c. On the Continent it has been found
by Prof. de Koninck in the Carboniferous limestone of Visé, Chokier, and 'Temploux,
in Belgium ; Karova, Government of Kalougarear, Moscou ; and at Sablé, in France.

Cuoneres Datmantana, De Koninck. Pl. XLVI, fig. 7.

CHONETES DaLMANIANA, De Kon. Desc. des Animaux foss. du Terrain Carb. de
Belgique, pl. xiii, fig. 3; pl. xiiis, fig. 2, 1843; and
Mon. du genre Chonetes, pl. xix, fig. 3, 1847.

Spec. Char. Shell thin, transversely semicircular, concavo-convex ; hinge-line as wide
as the greatest breadth of the shell. Ventral valve regularly, but moderately, convex ; area
narrow, sub-parallel, and divided in the middle by a small fissure, partly arched over by a
pseudo-deltidium. Dorsal valve concave, following the curves of the opposite one ; area

184 BRITISH CARBONIFEROUS BRACHIOPODA.

narrow ; surface of both valves covered with numerous fine, radiating striae, which become
more numerous as they proceed from the beak and umbo to the margin from bifurcation
and interstriation. Spines few on the surface of the ventral valve, but a row of longer
ones rise from and follow close to the cardinal edge. Interior unknown. Dimensions
variable ; a British example measured—length 8, breadth 14 lines.

Obs. 1 am but very imperfectly acquainted with this species. Certain fragmentary
specimens from the lower Scar limestone of Settle, in Yorkshire, could not be distin-
guished from some small Belgian examples of C. Dalmaniana 1 had received from
Prof. de Koninck, and for which reason the species (?) is, with some uncertainty, here
provisionally introduced. ‘The specimens I have been able to examine of the shell under
description appear to me intermediate in shape and character between C. papilionacea
and C. Hardrensis. Prof. de Koninck mentions that it can be distinguished from the
young age of C. papilionacea by its greater curvity (or convexity) and Jonger cardinal
spines; it appears, also, to attain larger dimensions than C. Hardrensis, which some
examples very closely resemble. Prof. de Koninck has given as synonyms of his
species Leptawna (Chonetes) volva and L. (Chonetes) multidentata of M‘Coy, but I
cannot coincide with this determination, for, as already stated, C. multidentata, M‘Coy,
evidently belongs to C. papilionacea, and I am almost disposed to look upon C. volva as a
variety of C. Hardrensis?

Cnonptres Bucwiana, De Koniack. Pl. XLVII, figs. 1—7, and 28.

Cnonptes Bucutana, De Kon. Descrip. des Anim. foss. du Terr. Carb. de Belgique,
pl. xiii, fig. 1, 1843.
— — Dav. A Monograph of Scottish Carb. Brachiopoda, pl. ii,
fig. 1, 1861.
Lrupr@na crasststr1a, M‘Coy. Synopsis of the Carb. Foss. of Ireland, tab. xx,
fig. 10, 1844; and British Carb. Foss., pl. iin, fig. 5, 1855.

Spec. Char. Shell marginally transversely semicircular, concavo-convex, about one
third wider than long; hinge-line straight, and either a little shorter, with its cardinal
angles rounded, or exceeding the width of the shell, with rectangular or slightly acute and
extended terminations. Both valves are provided with narrow sub-parallel areas; the
ventral one, which is the largest, being divided by a small fissure, partially covered with a
pseudo-deltidium, while in the middle of the ventral one there exists a prominent, V-shaped
cardinal process. ‘lhe ventral valve is moderately convex, and flattened towards its auri-
culate cardinal extremities. ‘The beak, which is small and incurved, does not overlie the
hinge-line. Dorsal valve concave, following the curves of the opposite one. Exteriorly
the surface of the ventral valve is ornamented with from twelve to thirty generally simple
ribs, with wider or narrower interspaces, the lateral ribs being sometimes larger than those
which occupy the middle of the shell; the dorsal valve is similarly ornamented. Spines

CHONETES. 185

short and not very numerous, on the surface of the valve, but a row rises and follows
close to the cardinal edge. In the interior of the ventral valve there exists a tooth on
each side of the fissure; the adductor muscular impressions are small, but prominent, and
separated by a median ridge or septum, which extends to about one third of the length of
the valve. Immediately under and outside of the adductor scars are two concave, sub-
quadrate, longitudinally grooved impressions, attributable to the cardinal or divaricator
muscles. In the interior of the dorsal valve, under the cardinal process, exists a mesial
ridge or plate, which extends to nearly two thirds of the length of the valve, and on either
side may be seen two well-defined muscular scars, which are produced by the quadruple
attachment of the adductor or occlusor muscle, while outside and in front of these are
situated the reniform impressions. ‘I'he remaining surface not occupied by muscular im-
pressions is in both valves covered with small asperities. Dimensions very variable ; three
British examples have measured—
Length 8, width 11, greatest depth between valves 1} lines

2
2? 6, ? 9, 2? 2 1 2?
2? (€ 2? 13, 2”? 9 2 9

Oés. This species is, in general, easily distinguished from its congeners by its strong,
simple ribs ; but although these are simple in the greater number of specimens, I have noticed
a tendency in a few rare instances to bifurcation and even interstriation close to the margin,
and especially so in one example from the gray Carboniferous limestone near Settle (fig. 7),
and which I had at one time distinguished by the varietal designation of ¢vferstriata. The
ribs are exceedingly variable in their number and strength in different specimens, and
every number between twelve and thirty can be counted in different examples, so
that the gradation is complete. It is highly probable, if not certain, that Prof. M‘Coy’s
C. erassistria is nothing more than a variety of C. Buchiana with small ribs, and, mdeed,
closely agrees with some Belgian examples of this last I received from Prof. L. de
Koninck.

In England the species under description occurs in the Carboniferous limestone of
Settle, and again im shales at Malham Moor, in Yorkshire, the specimens in the limestone
possessing, in general, a greater number and smaller ribs than in the variety which is met
with in the shales. It has been found also at Rutcheugh, in Northumberland. In
Scotland it occurs at Gare, in Lanarkshire, at 239 fathoms below “ Ell Coal,” and in
black Carboniferous shales (ca/y) at Bundoran, in Ireland. On the Continent it was
first discovered by Prof. de Koninck in the lower Carboniferous limestone of Visé, in
Belgium, where it is very rare.

186 BRITISH CARBONIFEROUS BRACHIOPODA.

Cuonetes Harvrensis, Phillips. Pl. XLVI, figs. 12—16, 17, 18, and 25?

Precten - - - = Ure. Hist. of Rutherglen and East Kilbride, p. 317, pl. xvi,
figs. 10, 11, 1793.
Cuonrres Harprensts, Phillips. Figures and Descriptions of the Paleozoic Fossils
of Cornwall and West Somerset, p. 138, pl. Ix, fig. 104,
1841.
Luprana (Cuonntrs) Harprensis, M‘Coy. British Pal. Foss., 454, 1855.
Cuonetius Harpronsis, Dav. Mon. of Scottish Carb. Brach., pl. ii, fig. 2, 1861.

Spec. Char. Shell marginally semicircular, wider than long, concavo-convex ; hinge-
line straight, and either a little shorter or somewhat longer than the width of the shell,
with rounded or angular terminations ; each valve is provided with a sub-parallel area, but
which is widest in the ventral one, and divided in the middle by a small fissure, partially
covered by a pseudo-deltidium; ventral valve moderately convex, sometimes slightly
depressed along the middle and flattened towards its auriculate cardinal extremities ;
the beak, which is small and incurved, does not overlie the hinge-line, while the dorsal
valve assumes in different specimens a greater or lesser degree of concavity, with, at times,
a slight longitudinal elevation along the middle, and flatness near the cardinal extremities.
The surface of both valves is covered with numerous thread-like, radiating, and often
bifurcating striae, which increase in number by the interpolation of striz at various
distances from the beak and umbo, so that as many as 120 striz may in some
examples be counted round the margin, while at irregular distances small spines
rise from their rounded surface in addition to those on each side of the beak; in
adult examples there exist along the cardinal edge from five to nine slanting, tubular
spines, which become longer and larger as they approach the extremities of the cardinal
edge. The valves are articulated by means of teeth and sockets, while the muscular
and other impressions do not differ materially from those already described in the
preceding species. Dimensions variable; an average-sized specimen has measured—
length 7, width 11, greatest depth 14 lines.

Oés. The determination of the present species has given me much trouble ; and
although I have spent much time in the endeavour to arrive at a satisfactory conclusion, it
is not without some hesitation that the term Hardrensis is here provisionally retained ;
provisionally, because I am as yet unable to determine whether Phillips’s Devonian shell
is the same as that to which Schlotheim, in 1820, applied the denomination sarcinulata,
as Prof. de Koninck’s illustrations of this last differ so much from those given by
Prof. Schnur and some other paleontologists. I am likewise uncertain whether J. de
©, Sowerby’s ZLept. sordida (1840) be really a synonym of the last-named shell, or
different from Phillips’s Hardrensis, as has been stated to have been the case by some
authors; and lastly, because my learned friend, Prof. de Koninck, who has paid so much

CHONETES. 187

attention to the species of the genus, maintains a different opinion to that here recorded,
while not absolutely denying the possibility of mine being correct.

Geologists and paleontologists have for many years been in the habit of distinguishing
the Chonetes we are at present describing by the name //ardrensis, and although
Prof. de Koninck, in page 206 of his ‘ Monographie du genre Chonetes,’ has referred this
shell and the one figured by Ure in 1793 to C. variolata, he subsequently determined
that our form could not be assimilated to D’Orbigny’s species, and proposed that the
Scottish shell, which occurs also at Visé, in Belgium, should be made a new species of
under the designation of C. alternata.' Waving received from Prof. Phillips the loan
of his four best and figured examples of C. Hardrensis, and having compared these with
our Scottish and other examples, the result was that I could perceive no difference in the
shape, areas, and striation, so that I deemed it preferable to allow the Chonetes we are
describing to retain the name Hardrensis. C. Hardrensis is certainly a very variable
species, and this has, no doubt, induced paleontologists to consider some of its variations
in shape to be distinct species. The striae vary much in number and strength. In
some specimens they are exceedingly numerous and fine, while in other examples they are
less numerous and coarser, the shell differmg also much according to age and locality.
C. Hardrensis (as | understand it) occurs in the limestone and shales of many English,
Scottish, and Irish localities. In England it is found at Settle, in Yorkshire ; Sturaway, in
Shropshire, Newton-on-the-More, Northumberland, &c. In Scotland it is met with at
Gare, in Lanarkshire, at 239 fathoms below “Ell Coal,” 343 at Raes Gill, 356 at Hill-
head. It occurs also at Capelrig, East Kilbride, Auchentibber and Calderside, High
Blantyre ; Brockley, near Middleholm, Lesmahago; Robroyston, north of Glasgow. In
Renfrewshire at Arden Quarry and Orchard Quarries, ‘Thornliebank. In Stirlingshire
im various stages, such as Craigenglen, Mill Burn, the Campsie main limestone, Corrie-
burn, &. In Ayrshire at West Broadstone, Beith; Auchenskeigh, Dalry; Goldcraig,
Kilwinning, &c. In Ireland it occurs in many localities in the counties of Dublin and
Kildare, &c.

In the shale above the ‘‘ Hosie limestone” at South Hill, Campsie, in Stirlingshire, we
find millions of specimens of a small variety (?) of the shell under description (fig. 22), but
it does not appear to have exceeded some two and a half lines in length by three in width,
the generality of specimens being even smaller. Mr. Young, to whom we are indebted for

! Having been enabled to compare a great many specimens of C. variolata, D’Orb., = C. granulifera,
Owen, with our Carboniferous C. Hardrensis, I could perceive little or no difference between many of the
specimens, although the ribs are at times, perhaps, finer and more numerous in certain examples of the
American C. variolata than in some specimens of Phillips’s species, so that Ido not consider Prof. de Koninck
to have been much mistaken when he referred Ure’s figures to D’Orbigny’s species. I may likewise observe
that the interior details are in both exactly similar. Chonetes striatella, Dalman, sp., from the Silurian
limestone of Gotland, closely resembles some examples of C. Hardrensis ; it is, however, a little more
concavo-convex, and I could not trace the existence of spines on its surface.

188 BRITISH CARBONIFEROUS BRACHIOPODA.

the knowledge we possess relative to this shell, thought it might be, perhaps, different
from C. Hardrensis, but 1 am inclined to look upon it as a simple local variation or
smaller race of the last-named species. In the shales of Newton-on-the-More and
Derwick, as well as in those of Rahoran, in Ireland, we find another variety, with very
fine strize, which Prof. de Koninck has identified as his Chonetes laguessiana (fig. 19
of my plate), ‘ Monographie du Genre Chonetes,’ p. 191, pl. xx, fig. 6; but after a very
careful examination of many specimens, I could not bring myself to consider it speci-
fically distinct from C. Hardrensis. Several of Prof. M‘Coy’s so-termed species appear
to me to be variations or synonyms of the shell under description, but as paleeon-
tologists may perhaps object to the view I have taken, it will be preferable as well as
desirable to allude to them under separate heads.

A.—Chonetes (Leptena) gibberula, M‘Coy. Synopsis of the Characters of the Carb. Foss.
of Ireland, pl. xx, fig. 11, 1843 (23 of my plate).

“ Semicircular, Jength two thirds the width, very gibbous in the middle ; ears acute,
flattened ; surface very finely and regularly striated longitudinally ; length one and a half
lines, width three lines.

Loc. “Calcareous slate of Lisnapaste, Ireland.” M‘Coy.

B.—Chonetes (Leptena) subminima, M’Coy. British Pal. Fossils, p. 456. Pl. iii,
fig. 31, 1855 (fig. 24 of my plate).

“ Rotundato-quadrate; length three fourths or four fifths of the width ; recelving
(ventral) valve very gibbous im the middle; greatest depth a little behind the middle ;
hinge-line as long as the shell is wide, forming flattened ears, slightly acute from the
sigmoid outline of the sides, having three or four moderately Jong, slender spines on each
side of the beak, extending backwards, as usual, in the plane of the margin; front margin
moderately convex. Surface uniformly covered with close, obtuse striae, once or twice
branched, but nearly uniform in size on all parts of the shell, and so fine that twelve at
the margin only occupy half a line when decorticated, the impressed lines between
the striae of the surface being coarsely punctured, and the beak slit by very deep
impressions of the mesial septum, extending half the length of the shell. Entering
(dorsal) valve nearly as concave as the receiving one is convex; surface similar in both
valves, the strize being crossed by fine, close lines of growth. Average width one and a
half line, the depth seems about half the width. Very abundant in a piece of the black
upper Carboniferous limestone of Derbyshire.” (M’Coy, p. 456.)

Obs. ‘These two so-termed species appear to me to be nothing more than young shells
of C. Hardrensis, and Prof. de Koninck has placed the first among the synonyms of
C. sulcata, which J am likewise inclined to look upon as a synonym of C, Hardrensis. 1

CHONETES. 189

think, however, that my Belgian friend is not quite correct while uniting Chone/es
crassistria to C. gibberula and sulcata, for reasons already stated.

c.—Chonetes (Orthis) sulcata, M‘Coy. Synopsis of the Characters of the Carb, Foss.
of Ireland, pl. xx, fig. 6 (fig. 20 of my plate).

“Semicircular, gibbous ; ears flattened ; surface with very coarse, rounded, frequently
branched striz ; hinge-line exceeding the width of the shell, furnished with ten strong,
conical spines.” (M‘Coy, p. 126.)

Loc. Arenaceous shale, Bruckless, Dunkineely.

Having had the advantage of being able to examine the original specimen in Sir
R. Griffith’s collection, I could not distinguish it from many specimens of C. Hardrensis.
The figure in the ‘Synopsis’ is not quite correctly drawn; that in my plate was taken
from the type.

D.—Choneles (Leptena) volva, M‘Coy. Synopsis of the Characters of the Carb. Foss.
of Ireland, pl. xvii, fig. 14 (fig. 21 of my plate).

“Semicircular, gibbous; ears involute, separated from the body of the shell by a
shallow depression ; hinge-line twice the length of the shell; furnished with twenty-four
slender, hooked spines ; surface covered with fine, flexuous striz. Length eight lines,
width one inch four lines.” (M‘Coy, p. 121.)

Loc. Lower limestone, Millecent, Clare, &c.

Oés. ‘Through the kindness of Sir R. Griffith I have been enabled to examine the
type and several other examples of this so-termed species, and I must confess that,
although I am not quite prepared to positively assert that C.volva is a synonym of
C. Hardrensis, I must observe that many of the specimens could not be distinguished from
the last-named shell. The strize are not simple, but arranged exactly as in C. Hardrensis,
of which it is very possibly nothing more than a variety. In his ‘ Monographie,’ Prof. de
Koninck has placed C. volva among the synonyms of his C. Dalmaniana, to which he has
added also C. multidentata. ‘This last belongs to C. papilionacea ; but I am convinced that,
had my learned friend been able to study the original types of several of M‘Coy’s so-termed
species of Chonetes, he would have arrived at different conclusions.

8.—Chonetes (Leptena) perlata, M‘Coy. Synopsis of the Characters of the Carb. Foss.
of Ireland, pl. xx, fig. 9 (fig. 25 of my plate).

“Semicircular, nearly twice as wide as long, convex; front margin nearly straight ;
surface marked with very fine, longitudinal, slightly flexuous striz ; hinge-line with about
eight long, slender spines, set nearly at right angles; length three lines, width five and a
half lines.”” (M‘Coy, p. 120.)

190 BRITISH CARBONIFEROUS BRACHIOPODA.

Loc. Carboniferous slate of Rahoran, Fivemile Town, Ireland.

Obs. Prof. M‘Coy states that this species seems closely allied to that which he has
figured under the name of Leplaena serrata, but is distinguished by its angular plaits and
rounded extremities, the radiating ridges being striated transversely. I have examined
the original example, and must say that it appeared to me to be nothing more than a small
specimen or young shell of C. Hardrensis. Prof. M‘Coy has exaggerated the inward
curve of the spines, and the enlarged illustration of the striae is not correct, being exactly
similar in the specimen to what we find in C. Hardrensis.

CHonetes pouita, M‘Coy. Pl. XLVII, figs. 8—11.

Lupta@na (CHONETES) PoLiTa, M‘Coy. British Paleeozoic Fossils, p. 456, pl. 11»,
fig. 30, 1855.

Spec. Char. Shell transversely semicircular, concavo-convex ; hinge-line slightly
longer than the width of the shell, with a narrow, sub-parallel area in either valve, the
ventral one, which is the widest, being divided in the middle by a small fissure, arched
over with a pseudo-deltidium, both valves being articulated by the means of teeth and
sockets ; ventral valve gibbous, much vaulted in the middle and at the beak, which last is
small, and does not overlie the cardinal edge ; dorsal valve concave, following the curves of
the opposite one. Surface of both valves smooth, and marked only by fine, concentric lines
of growth, a few scattered spines rising from the surface of the larger valve, and two or
three longer ones project from the cardinal edge on either side of the beak. In the
interior of the ventral valve the muscular impressions are very feebly marked, and are
divided by a small mesial ridge or septum, while pustule-markings rise from the whole
remaining surface. In the interior of the dorsal valve, under and a little lower down than
the cardinal process, there exists four small impressions left by the adductor or occlusor
muscle, while two prominent ridges divide the central pair, and are prolonged to about
two thirds of the length of the valve, the remaining portion of the valve being covered with
elongated pustular markings. Dimensions very variable ; two specimens have measured —

Length 23, width 3 lines.

pe ORE Ty

Obs. This remarkable little shell is at once distinguished from all its congeners by
the smoothness of its valves, as well as by the two peculiarly prominent ridges in the
interior of the dorsal valve, and which are likewise present in one or more Silurian species.
Prof. M‘Coy remarks that this form has much the shape of C. volva, but is not so
wide, is more gibbous, and is the only Carboniferous species he knows that has a smooth
surface.

In England it is stated by Prof. M’Coy to be rare in the dark Carboniferous limestone
of Lowick, Northumberland, that it occurs at Mount Rath, in Ireland, and we are indebted
to the great zeal of Mr. Young for his discovery in Scotland, and where it occurs in vast

29

CHONETES. 191

numbers in the Craigenglen beds in Stirlinghire, and, as far as their position is at present
known, in the lowest portion of the marine limestone, or close upon the horizon of the
Scabricula limestone.

We will now conclude this perhaps unsatisfactory account of the British Carboniferous
Chonetes by reproducing the description given by Prof. M’Coy of two very doubtful so-
termed species.

Thonetes (Leptena) serrata, M‘Coy, Synopsis of the Char. of the Carb. Voss. of Ireland,
pl. xviii, fig. 10 (fig. 26 of my plate).

*‘Semicircular, convex; surface covered with numerous, rather coarse, branched
ridges ; hinge-line equal to twice the length, straight, furnished with twenty small, hooked
spines ; breadth ten lines, length five lines. One of the rarest fossils we have.’ (M’Coy,
p- 121.)

Obs. Ihave seen the original undeterminable fragment upon which this so-termed
species has been fabricated, and which was obtained from the lower limestone of Millecent,
in Ireland. Prof. de Koninck has referred it to C. variolata, but I would not venture
to emit any opinion based upon such insufficient material.

Chonetes (Leptena) tuberculata, M‘Coy. Synopsis of the Characters of the Carb. Limest.
of Ireland, pl. xx, fig. 5 (fig. 27 of my plate).

“Semicircular, convex ; length two thirds the width ; surface with about forty-eight
thick, rounded, dichotomous, smooth ribs, each bearing towards the margin a row of from
five to eight round tubercles.

“This curious little species is nearly semicircular, the hinge-line being much shorter
than the width of the shell; moderately convex ; the radiating ribs are thick, smooth, and
distinctly separated, branching as they approach the margin, where they bear a row of six
or eight little round tubercles. Length five lines, width eight lines.” (‘ Synopsis,’ p. 121.)

Loc. The lower Carboniferous limestone of Millecent, Clare, Ireland.

Oés. Iam acquainted with the original specimen, which consists of a single valve, in
the collection of Sir R. Griffith, but upon such insufficient material would not venture to
pass any decided opinion as to its specific claims.

192 BRITISH CARBONIFEROUS BRACHIOPODA.

Family—CRANIADA.

Genus—Cranta, Retzius, 1781.

The shells composing this remarkable and widely spread genus vary much in shape,
although not much difference has taken place in this respect in time, for some Palzozoic
species can hardly be distinguished from more recent and even living types. They are all
marginally more or less circular or sub-quadrate, rarely free, but generally attached to
marine bodies by the beak (when such does exist) or by the entire surface of the lower
or ventral valve ; and it is from this circumstance that the ventral or attached valve varies
so much in shape and sculpture. The upper or dorsal valve is always more or less limpet
shaped, with a sub-central vertex, the surface being smooth or variously sculptured by
concentric or radiating striz, or ribs, some also possessing a spiny investment. There
exists no articulated hinge, the valves being kept in place by a peculiar disposition of
the muscles ; and although the animal has not been hitherto completely investigated, we
will give figures of the interior of the valves, for the sake of explaining the more recent
but provisional interpretation and names that have been applied to the muscular
impressions by Mr. Hancock. But we must hasten, at the same time, to observe that the
interior appearance and shape of the muscular and other impressions are very different
in detail in certain species, although very similar in others. he figures here given will,
however, suffice to explain the general character.

Dorsal or free valve. Ventral or attached valve.
Crania Ignabergensis (var.), Cretaceous.

a. Occlusor (Hancock) = anterior adductors (Woodward).

r. Divaricator (H.) = posterior adductor (W.).

v, p. Ventral adjustor (H.).

d, p. Dorsal adjustor (H.) = protractor sliding muscle (W.).

p, 8. [?] Anterior extremity of dorsal adjustor (H.).

6, p. Brachial muscle, posterior extremity (H.) = retractor sliding muscles (W.).

6. Brachial muscle, anterior extremity (H.) = retractor sliding muscles (W.).

n. Mesenteric muscle, destined probably to draw the alimentary tube backwards (? H.).
o. Ovarian (?), m. granulated margin.

CRANIA. 193

Mr. Hancock, who, at my request, in May, 1859, examined the animal of three or four
badly preserved specimens of C. anomala (the only examples then to be procured), has
informed me that the impressions a are undoubtedly due to the occlusors, 7 to the divari-
cators, and that when the former muscles relax and the latter contract, the fluid in the
perivisceral chamber will be forced forwards, and thus the valves will be opened a little in
frout, the action being the same as in Lingu/a; that v,p, is due to what may be termed
the ventral adjustors ; that these muscles form a scar close to the outer border of the divari-
cator in the ventral valve ; the other extremities of this muscle converge and pass round
the outer margin of the occlusor, to which they adhere, but Mr. Hancock could not
exactly determine how they terminate ; d, p, are considered due to the dorsal adjusters (?),
one end of the muscle being attached to the dorsal valve, close to the outer border of the
divaricators, the other most probably to the anterior process of the ventral valve. Although
this could not be satisfactorily determined, from the very indifferent state of preservation
of the specimens, at any rate the fibres of this extremity were firmly united to the inner
border of the occlusors. ‘The brachial muscle has both its extremities attached to the same
valve (the dorsal), the anterior end to the ventral process, the dorsal close to the outer
margin of the occlusor, with which it blends its fibres; that the arms are fixed to these
muscles, which, perhaps, may be named the brachial. The mesenteric (z) is a flat, thin,
membranaceous muscle, binding the dorsal mysentery to the process of the hinge-margin,
to which, according to Mr. Woodward, the cardinal muscle is attached ; but we may hope
that, before long, Mr. Hancock will have been able to investigate anatomically some well-
preserved examples, which may be dredged alive, close to some portions of our Scottish or
Trish shores. The oval arms are thick, fleshy, and spirally coiled, the volutions are few,
and directed vertically towards the cavity of the dorsal valve, somewhat as is seen in
Discina and other genera. We may also notice that the brachial muscle is very closely
united to the occlusor; that it is difficult to distinguish the two in the generality of
specimens.

Dr. Carpenter has stated the structure of the shell in this genus to be widely
different from that of Brachiopoda generally, but as still conformable to it in being
penetrated by canals which are prolonged from the lining membrane of the shell, and
which pass towards its external surface, these differmg, however, from ‘Terebratule in not
arriving at that surface, and in breaking up into minute subdivisions as they approach it.

Although three so-termed species of British Carboniferous Crania will be here described,
C. quadrata is the only well-determined species. Of Crania? trigonalis | have never
seen any other than the original type, and a sight of its interior would be necessary prior
to the species being definitely adopted. Of Crania? (Patella) Ryckholtiana, De Koninck
= C. vesicularis, M‘Coy, I am acquainted with but a single Irish specimen.

194 BRITISH CARBONIFEROUS BRACHIOPODA.

Cranta auaprata, M/‘Coy. Pl. XLVITI, figs. 1—13.

OrBicuLa quaprata, M‘Coy. Synopsis of the Char. of the Carb. Foss. of Ireland,
pl. xx, fig. 1, 1844.
Cranta auaprata, Dav. Mon. of Scottish Carb. Brach., pl. v, figs. 12—21, 1860.

Spec. Char. Very variable in shape, on account of its mode of attachment, which is
by the entire surface of its lower valve; when quite regular, is marginally sub-quadrate,
almost circular, or slightly elongated, oval, the posterior edge being usually straight, or
with a slight mward curve, while the shell is at the same time wider anteriorly than
posteriorly. ‘The upper or free valve is conical or limpet-like, the vertex being sub-central
and closer to the posterior than to the anterior margin. Externally, the surface is marked
with numerous but irregular concentric striz or lines of growth, which give to the shell
a somewhat roughened appearance. ‘The interior of the attached or ventral valve is sur-
rounded by a raised, thickened border, of moderate width, and upon it the tubular shell-
structure is sometimes clearly discernible. In each corner of the disc, close to the posterior
inner margin of the raised border, may be seen two somewhat circular, slightly convex,
and prominent, but widely separated, muscular scars; while towards the centre of the disc
two other prominent, but appropriate, muscular impressions exist, and which are, at the
same time, somewhat hollowed out along their middle."

The interior of the upper or free valve shows in each corner of the disc, close to the
posterior inner margin of the border, a convex, oval-shaped, muscular prominence (and
which is, according to Mr. Hancock, due to the divaricator muscle), while towards the
centre of the valve are two prominent approximate impressions, which are referred by the
same authority to the adductor or occlusor muscles. Dimensions very variable; a large
example measured—length 7, width 7 lines. The generality of specimens are, however,
much smaller.

Obs. The mode of existence peculiar to this as well as to other similarly constructed
species is the cause of the great irregularity in shape assumed by the larger number of
individuals, for it was the habit of the young of this as well as of other species of the
genus to fix themselves as parasites to all kinds of marie objects, and they were some-
times so numerously and closely clustered together that their individual regular growth
was prevented, from which it can be easily understood that in such cases the animal must
have been compelled to develop itself in whatever direction it could find available space.
When first formed, and up to a certain age, the shell of the attached valve was exceedingly
thin, and adhered so closely to the surface of the object to which it was fixed as to have

1 Mr. Hancock attributes the two first-mentioned scars to the divaricator, while the central pair are
referred to the occlusor; the other muscular, ovarian, and vascular impressions which should exist in the
interior were not sufficiently defined in the present species to admit of their being accurately described.

CRANIA. 195

reproduced all the equalities of its surface, but with age, and from the shell acquiring
greater thickness, these inequalities were generally levelled. Nor is it an uncommon cir-
cumstance to find the roughness or sculpture of the object to which the lower valve adheres
likewise reproduced upon the outer surface of the upper or unattached valve, in a similar
manner to what we find to be the case with certain species of oyster. It is no easy matter
to distinguish certain forms of Crania, as several species bear so close a resemblance to each
other, and it was not until I had been able to study the original type of Prof. M‘Coy’s
Orbicula quadrata (kindly communicated by Sir R. Griffith) that I could identify it with the
same form which occurs so abundantly in the Carboniferous shales of Scotland.

In England but few examples have been hitherto discovered; one or two specimens
were found by Mr. C. Moore, at Holwell, near Frome. In Scotland it occurs at Gare,
in Lanarkshire, at 239 fathoms below “ Ell Coal,” 343 at Langshaw Burn, and 375 at
Kilcadzow. It occurs also at Auchentibber and Calderside, High Blantyre; Capelrig,
East Kilbride ; Brockley, near Lesmahago; and Robroyston, north of Glasgow. In Ayr-
shire, at West Broadstone, Beith ; Goldcraig, near Kilwinning ; Cessnock, near Galston ;
and on the bank of the stream Pomillen, near Strathavon. In Renfrewshire, at Howood,
near Paisley ; and Orchard Quarry, Thornliebank. In Kircudbrightshire, in strata cropping
out on the seashore, near Kircudbright. In Stirlingshire, in the Balglass Burn beds, and
in those of the Campsie main limestone. In Ireland it was found in Carboniferous shale
at Rahan’s Bay, in Donegal, one mile south-west of Dunkineely village. On the Continent
it occurs at Tournay, in Belgium ; and at 'luscombia, Alabama, in America.

Cranta Rycxnoutiana, De Koninck. Pl. XLVIIL, figs. 15, 16, 17?

Paretta Ryckuoitrana, De Kon. Animaux Foss. de la Belgique, pl. xxiii, fig. 5,
1843.
CRANIA VESICULARIS, M‘Coy. Synopsis of the Char. of the Carb. Foss. of Ireland,
pl. xx, fig. 3, 1844.

Spec. Char. Ovato-orbicular, nearly circular, or slightly longer than wide. Upper
valve conical, limpet-like, the vertex bemg sub-central and closer to the posterior than to
the anterior margin ; surface smooth, marked only by a few concentric lines of growth ;
lower or attached valve unknown. Dimensions variable; two British examples have
measured—

Length 8, width 10, depth 6 lines.
Stay Lest galt Wess page A SS

Obs. It appears quite probable that the Patel/a Ryckholtiana and Crania vesicu-
laris belong to the same species, but unfortunately, although several exteriors of the
upper valve have been discovered, no example showing the interior has hitherto turned up.
In England it has been found in the Carboniferous limestone of Castleton, in Derbyshire.

196 BRITISH CARBONIFEROUS BRACHTIOPODA.

In Ireland it is mentioned from the limestone of Millecent, in Kildare. No Scottish
specimen has hitherto been discovered.

Cranta? triconaLis, M/‘Coy. Pl. XLVIII, fig. 14.

OrBIcuLA TRIGONALIS, M‘Coy. Synopsis of the Carb. Foss. of Ireland, pl. xx, fig. 2,
1844.

Spec. Char. “Conical, obovate, trigonal; anterior end narrow, rounded ; posterior
sub-truncate ; surface irregular, marked with close, rounded, radiating ridges from
the beak, which is small, deflexed, and little more than one fourth the length from
the anterior margin. Length four and a half lines, width three lines.” (‘ Synopsis,’ p. 104.)

Obs. I have reproduced Prof. M‘Coy’s description, as I know so little about the
shell, a single valve having been hitherto discovered, and which was kindly lent me by Sir R.
Griffith ; and although I would not dare to assert that it positively belongs to the genus
Crania, it appears to me more probably so than to Discina, where placed by the author
of the ‘Synopsis.’ C.? trigonalis was obtained from the Calciferous slate of Lisnapaste, in

Treland.

Famnily—DISCINID/.

Genus—Discixa, Lamarck, 1819.

The shells belonging to this genus are usually circular or longitudinally oval, the
larger or imperforated valve being conical, or limpet-like, with the apex inclining towards
the posterior margin. ‘The lower valve is conical, opercular, flat, or partly convex, and
perforated by a narrow, oval, longitudinal slit, which reaches to near the posterior margin,
and which in recent species is placed in the middle of a depressed disc, the shell being
always attached to marine bodies by means of a pedicle, and never by the substance of the
shell, as in Crania. ‘The valves are unarticulated, and kept in place by a particular disposi-
tion of muscles, the occlusor and divaricator impressions being somewhat similarly situated
to those of Crania. Much has still to be done before the animal will have been completely
or satisfactorily anatomically investigated. ‘he so-termed oral arms have been described
by Mr. S. P. Woodward, in his excellent ‘ Manual,’ as being curved backwards, returning
upon themselves, and ending in small spires, directed downwards towards the ventral valve,
and the only process which could possibly have afforded support to the arms is developed
from the centre of the ventral valve, asin Crania. In recent species the shell is stated by Dr.
Carpenter to be horny and minutely punctate, the tubuli being generally arranged in fasciculi,
so that their transverse sections present a series of dots. Dr. Gratiolet believes, however, that
the shell is not entirely composed of a horny substance, but somewhat similar to that of

DISCINA. 197

Lingula, although the calcareous element is enormously greater in the last-named genus. The
chemical composition of the shell of Discina has been stated by Mr. S. Cloéz to be
. similar to that of Lingula, of which an analysis will be found further on.

Discina appears to have existed during almost the entire series of Palaeozoic and
Mesozoic periods up to the present day, and it is probable that the animal was not at
any period the inhabitant of very deep water, for all the recent species of Lingula and
Discina, or those species with a horny shell, have prevailed in the littoral zone, and do not
appear to have descended deeper than about eighteen fathoms. The reader is referred for
more ample details to Prof. Suess’s excellent ‘Memoir on the Habitat and Distribu-
tion of the Recent and Fossil Brachiopoda’ recently published in Vienna.

One or two British species only have been hitherto found in the Carboniferous
rocks.

Discina nitipa, Philips. Pl. XLVIII, figs. 18-—25.

OxpicuLa niTiDA, Phillips. Geol. of York., vol. ii, p. 221, pl. ix, figs. 10—13,
1836.
— cincta, Portlock. Report of the Geol. of Londonderry, &c., pl. xxxii, figs.
15, 16, 1843.
Discina BuLLA, M‘Coy. British Paleozoic Fossils, pl. iii p, fig. 32, 1855.
— witipa, Dav. Mon. of Scottish Carb. Brach., pl. v, figs. 22—29, 1860.

Spee. Char. Shell marginally circular or elongated oval, the posterior portion being
rather narrower than the anterior one. The larger or free valve is conoidal or limpet-
like, and more or less elevated, the pointed apex being situated at variable distances
between the centre and the posterior margin, but it is not always the most elevated portion
of the valve. ‘The surface is covered with numerous small, irregular, concentric wrinkles
or striae. The smaller or lower valve is somewhat flattened or slightly concave towards
its anterior margin, with an oval-shaped foramen, surrounded by an elevated, convex
margin, Which extends from near the centre of the valve to a variable distance from the
posterior edge. ‘This valve is likewise ornamented with numerous small, irregular, con-
centric ridges or wrinkles, with small, flattened interspaces. No interiors have been
hitherto obtained. Dimensions variable; three examples have measured—

Length 103, width 10, depth 6 lines.

i i ee AEE Ramee
» 7 ae MO siee hae os

Obs. After a lengthened examination of Discina cincta, as well as of Discina bulla,
I could perceive no valid grounds for separating these two so-termed species from
D. nitida ; and any one possessing a sufficiently numerous series of specimens of the last-
named form would, I think, soon perceive that Phillips’s shell presented every degree of
elevation—from that of an almost depressed shell to that extreme “inflated, bubble-like

198 BRITISH CARBONIFEROUS BRACHIOPODA.

form” described by Prof. M‘Coy. I am therefore quite disposed to concur in the
Irish author’s opmion when he considers D. cincta as nothing more than the perfect
condition of D. nitida; for when the outer surface of the last-named shell is absent,
which is often the case, the cast is generally almost smooth, or marked only with a few
faint concentric and radiating lines, a circumstance which has apparently led some palzeon-
tologists to believe that Phillips’s shell was smooth, while that of Portlock’s was concen-
trically striated.

It is also highly probable that the Permian Discina Koninckii cannot be specifically
separated from the Carboniferous D. nitida.

Discina mtida is a common shell in many localities. In England it is mentioned by
Prof. Phillips to occur at Bowes, Pateley bridge, Lee Harelaw and Otterburn; also
at Coalbrookdale. It has been found also at Lowick, Northumberland ; in the upper part
of the Carboniferous limestone of Derbyshire, &c. In Scotland it abounds at Belston
Place Burn, in Lanarkshire, at 173 fathoms below “ Ell Coal,” 239 at Gare, 265 at
Belston Burn, and 354 at Raes Gill, in the parish of Carluke. It is likewise found at
Haw-hill, near Lesmahago; Auchentibber and Calderside, High Blantyre; and Capel-
rig, Hast Kilbride. In Renfrewshire, at Arden Quarry, Thornliebank. In Stirling-
shire, at Craigenglen, and in the Balgrochen Glen ironstone, &c. In Ayrshire, at Cragie,
near Kilmarnock ; Cessnock, parish of Galston; and Netherfield, near Strathavon. In
Vifeshire, at Strathkenny, St. Andrew’s, &c. In Haddingtonshire, at Cat Craig, near
Dunbar. It occurs also in Edinburghshire, and along the Berwickshire coast, from the
mouth of the Tweed to Ross. In Ireland it occurs at Benburb, Bundoran, Culkagh. In
America it has been found in Pike and Adams County, Illinois, &. &e.

Discina Davreuxtana, De Koninck. Pl. XLVIILI, fig. 26.

OrpicuLa DavreuxtaNna, De Koninck. Desc. des Animaux Foss. du Terrain Carb. de
Belg., p. 306, pl. xxi, fig. 4, 1843.

Spec. Char. Shell marginally oval, longer than wide ; larger or upper valve conoidal
or limpet-like, the apex being situated between the centre and the posterior margin.
Surface smooth, with concentric, rounded wrinkles. Lower valve unknown. Length 3,
width 23, depth 1 line.

* Obs. I am acquainted with but a single British example, which was found by
Mr. Joseph Wright in the Carboniferous limestone of Little Island, near Cork, in Ireland.
‘The specimen bears a close resemblance to the O. Davreuxiana, but 1 am still uncertain
whether this last is a good species or only a variety of D. nitida, the material at my com-
mand not being sufficient to enable me to decide the question. In Belgium it occurs
near ‘Tournay.

LINGULA, 199

Family—LINGULID.
Genus—Lincuua, Bruguiere 1789.

‘The limit of variation among the shells composing the genus Lingula appears to be
more restricted than what is prevalent among the generality of other genera and species of
Brachiopoda. It is, therefore, very often no easy matter to distinguish and correctly
determine some fossil species, even when occurring in different and often widely separate
geological periods.

The shell of Lingula is thin, equilateral, usually longer than wide, and broader at the
front than at the beaks, which are likewise more or less pointed, while the front is either nearly
straight or with a slight inward or outward curve. ‘The shell is also sub-equivalve ; the
extremity of the beak of the dorsal valve being somewhat more elongated and pointed than
that of the ventral one.’ ‘The external surface is also either nearly smooth or concentri-
cally striated. The valves are usually moderately convex, and generally deepest or most
elevated towards the beak, and become more flattened as they approach the front. ‘The
apex of the dorsal valve is likewise situated quite close to, but not contiguous with, the
rounded margin of the beak, and by which character the valves can be readily distinguished
both in the recent and fossil condition.

When alive, the valves of Lingula were slightly gaping at each end, contiguous only
along the lateral margins; but the animal could, at its will, by the action of certain
muscles, close or draw together one or other extremity ; nor does there exist any articu-
lation, the vaives being kept in place by the means of a complicated system of muscles, to
be hereafter described. ‘The animal was also provided with a very long pedicle, of a
peculiar construction, which was chiefly attached to the inner groove situated in the beak
of the ventral valve; and when alive, did not inhabit great depths, most recent species
having been found at low water, buried im sand.

The intimate shell-structure of Lingula has been described by Dr. Carpenter, and we
will therefore only refer to Dr. Gratiolet and Mr. S. Cloéz’s more recent observations.
The first-named savant states that the shell is composed of two distinct elements, the one
being horny, the other shelly. That they are disposed in layers, or thin laminz, which
succeed each other alternately from the convex surface of the valves, the outer or superficial
one being horny ; that these layers have not the same thickness, the testaceous ones being
the thickest on and near the visceral side, while the horny ones are more so towards the
exterior surface ; and that while the horny layers are entirely formed of parallel fibres,

! Anatomists appear to differ as to the names by which the valves should be designated; it may
therefore be as weil to mention those that are synonyms. ‘The shortest is the dorsal valve of Woodward,
Hancock, &c. ; = valve inférieure, Gratiolet ; = valve droite, Vogt. The longest is the ventral valve of
Woodward, Hancock, &c. ; = valve supérieure, Gratiolet ; = valve gauche, Vogt. Mr. Hancock is of opinion
that if the names of the valves were to be changed, that they should be called anterior ard posterior. In
this monograph we will continue to make use of those first mentioned.

200 BRITISH CARBONIFEROUS BRACHIOPODA.

without trace of perforations, the testaceous ones are traversed by a multitude of minute
canals, recalling those of the Terebratulide.t Mr. S. Cloéz has likewise shown that the
valves of Lingula, when dried at 100°, contain, for 100 parts—

Organic matter. 5 . ; , : 45°20
Carbonate of lime : : : ; : 6:68
Phosphate of lime A ; : 5 : 42°29
— of magnesia . : : . : 3°85
— _ of sesqui-oxide of iron : : : 1:98
Silica. : . : - : : Traces.

This distinguished French chemist observes, at the same time, that this composition of
the test of Lingula approximates to that which M. Chevreuil signalised in the scales of the
Lepidostria, as well as to the test of insects as described some years ago by Hatchett.

cp’

Liew Fie. 2.

Lingula anatina (recent).
Fig. 1. Ventral valve, Woodward, Hancock, &c.; valve supérieure, Gratiolet.
Fig. 2. Dorsal valve, Woodward, Hancock, &c.; valve inférieure, Gratiolet.
p,@. Posterior occlusor, Hancock ; = anterior adductors, Woodward ; = pré-adducteurs, Gratiolet ; = untere schiese
muskelbiindel, Vogt ; = muscles qui vont directement d’une coquille a l’autre, Cuvier.
a,a. Anterior occlusor, Hancock ;= anterior retractors, Woodward ; = muscles obliques postero-antérieurs, Gratiolet ;
= mittlere schiese muskelbindel, Vogt.
r,7, 7. Divaricator, Hancock ; = posterior adductor, Woodward ; = post-adducteurs, Gratiolet ; = oberer schliessmuskel,
Vogt.
p, p- Posterior adjustor, Hancock ; = posterior retractors, Woodward; = muscles croisé ou oblique transverse,
Gratiolet.
e,p. External adjustor, Hancock ; = external protractors, Woodward ;=surface sur laquelle se prolonge l’insertion
du muscle oblique antero-postérieur paire externe, Gratiolet.
¢, p, and ec’, p’. Central adjustor, Hancock; = central protractor, Woodward. c, p. Muscles obliques antérieurs
paire interne, Gratiolet ; and ec’, y’, muscles obliques antérieurs paire interne et externe, Gratiolet.

Ds Line indicating the posterior parietals, Hancock ; = peaussier verticaux, Gratiolet.

Dp Peduncular muscle, Hancock ; = capsule of pedicle, Woodward ; = muscle intérieur du pedoncule, Gratiolet.
i. Impressions produced by the central branches of sinuses, Hancock.

8. Impressions produced by the outer or lateral branches of sinuses.

Impressions produced by pallial lobe.

’ I have considered it desirable to reproduce these details, as they are important to British Palzeonto-
logists, and have been taken from the first portion of Dr. Gratiolet’s recently published memoir on ‘The
Anatomy of Lingula anatina ; and I avail myself of the present opportunity to express my grateful

LINGULA. 201

In the interior of the valves may be seen a number of muscular and other impressions
with which the palaontologist should become acquainted, but it would be out of place
were we to enter into a minute anatomical description of the animal itself in a work
exclusively devoted to fossil species. We will therefore briefly place before the reader a
few details only concerning those muscles which have left recognisable impressions in the
interior of the valves. It must also be observed that, although Mr. Woodward, Mr. Hancock,
Dr. Gratiolet, and others, agree as to the shape and position of the various muscles, they
do not interpret the functions of some of these exactly in the same manner, and as a
number of names have been applied to designate the same muscle, the first thing to do
will be to place before the readers figures showing the position of the impressions and the
synonymous terms that have been employed, and these will also save us the necessity of
describing the scars, which a glance at the figures will explain far better than could be
done by simple words.

The muscular system is much more complex in the unarticulated divisions of the
Brachiopoda than in the articulated groups. While describing their shape and direction
we cannot do better than to follow what has been said by Mr. Hancock in his admirable
memoir upon the “Anatomy of the Brachiopoda,” published in the ‘ Philosophical Tran-
sactions of the Royal Society,’ 1858 :

The anterior occlusors “are a pair of stout muscles, of about equal thickness through-
out; they pass from the ventral valve, one at each side, in front of the visceral mass, and
inclining forwards and inwards, they go to be attached to the sides of the central ridge
of the dorsal valve, about one third of the length of the shell from the anterior margin.
The dorsal extremities are compressed, and have their sides in contact.”

The posterior occlusors “ave rather stouter and much stronger, and go directly from
valve to valve, parallel with each other. ‘The ventral extremities are placed a little in
advance of the corresponding terminations of the anterior pair, and the dorsal extremities
of the former are situated a little behind those of the latter.”

The divaricator, “though forming a single mass, is really two muscles combined. — It
is short and stout, and is situated at the posterior extremity of the perivisceral chamber,
passing directly between the valves, and having its attachments immediately within the
umbones. ‘The extremities have a semicircular form, arched behind, and slightly bitid
in front, indicating its double nature.”
thanks to the distinguished French anatomist for the high honour he has conferred by dedicating to me
the result of his admirable researches. For details concerning the animal of Zingula I must refer the reader
to the following memoirs :—Cuvier, ‘Memoire sur l’Animal de Ja Lingula,’ 1797 and 1802. Vogt, ‘ Ana-
tomie der Lingula anatina,’ 1845. Owen, “On the Anatomy of the Brachiopoda,” ‘Trans. of the Zool.
Soc.,’ 1835 ; as well as in Davidson’s ‘General Introduction,’ chap. 1, 1853. 8S. P. Woodward, ‘ Manual
of the Mollusea,’ 1854. But especially to the magnificent memoir by Hancock, “On the Organization of
the Brachiopoda,’ ‘Trans. Royal Soc.,’ 1858. As well as to Gratiolet’s most important and excellent
memoir, ‘* Etudes Anatomiques sur la Lingula anatina,” in the ‘Journal de Conchyliologie,’ for January
and April, 1860.

26

202 BRITISH CARBONIFEROUS BRACHIOPODA.

The central adjustors.—* This pair are attached to the ventral valve by fine points
between the posterior occlusors in front; they are placed close together, one on each side
of the median line. Sweeping round the inner border of these muscles, they diverge
posteriorly, and increasing in size as they go, ascend towards the dorsal valve, to which
they become adherent, one on each side, immediately within the parietes of the body.”

The eaternal adjustors “arise from the ventral valve, at the outside of the posterior
occlusors, and in contact with them. They are at first pretty stout, but on passing out-
wards and backwards they enlarge a little, and ascending, are inserted into the dorsal
valve, one on each side, immediately behind the central pair.”

The posterior adjustors “are large and powerful muscles, and though they may be
considered as a pair, they are asymmetrical, there being two on one side and only one on
the other. As they pass across from valve to valve they intersect each other, the single
one passing between the other two. The single one is as large as the other two both
together, and is attached to the left side of the ventral valve, about midway between the
divaricator and the anterior occlusor. From this point it passes diagonally upwards and
forwards. ..and on reaching the opposite side of the dorsal valve has the other end inserted
into the latter, immediately within the posterior terminations of the external and central
adjustors of the same side. At the points of attachment the three muscles are pressed so
close together that they appear at first sight as only one. ‘The two opposite posterior
adjustors take their origin from the right side of the ventral valve, considerably apart ;
but both of them close to the lateral parietes of the body, one only a little in advance of
the divaricator, and the other a short distance further forward. They converge as they
penetrate the visceral mass, and sloping forward, one on each side of the visceral muscle,
with the alimentary tube above them, they ascend to their insertion into the left side of
the dorsal valve, directly within those of the external and central adjustors. ‘Therefore at
this point there are the terminations of four muscles in close contact.”

The peduacular muscle “ has its insertion immediately within the umbo of the ventral
valve, and close behind the divaricator.”’

# is a line indicating attachment of the posterior parietals.

There are some other muscles, but as they do not leave any impressions upon the
surface of the shell, will not require to be recorded here ; but now that the reader has had
the names, shape, and direction of the muscles explained, it will be necessary to mention
as briefly as possible what are their supposed functions, and for this purpose I will
particularly mention the views of Mr. Hancock and Dr. Gratiolet, as they are the authors
who have more recently examined the animal with the greatest attention. In order to
avoid the possibility of error upon my part, I requested the last-named two anatomists to
kindly transmit me their views, which I will now transcribe.

According to Mr. Hancock, the functions of the various muscles might be shortly
described as follows :

“The anterior and posterior occlusors are mainly instrumental in closing the valves.

LINGULA. 203

“The divaricators are the chief agents in opening them. When they contract, the
umbonal regions of the valves are approximated, and thus pressing forward the fluid in the
peri-visceral chamber, their anterior margin is separated.

“The primary function of the three pairs of adjvstors is to keep the valves opposed to
each other, or, in other words, to adjust them, and in this respect to compensate for the
deficiency of the hinge and condyles. When in full action and in co-operation with
the occlusors and divaricator, they likewise assist in closing the valves. ‘The adjustors
are the sliding muscles of those authors who believe in the sliding of the valves over each
other. ‘The anterior occlusors have had a similar function assigned to them.

“The peduncular muscle attaches the shell to the peduncle, and has probably the power
of moving the former upon the latter.”

Some doubt exists concerning the homology of the adjustor muscles (in Lingula), but
Mr. Hancock has not expressed any strong opinion on the point ; he thought it likely that
the muscles so named in the articulated and unarticulated genera of Brachiopoda were
probably homologous, but is ready to admit that he may be possibly mistaken, and, if so,
he would not, however, be disposed to change the names, for in both divisions the function
of these muscles is to adjust the valves. It is only necessary to keep in view that they
are zot homologous.

We will now give Dr. Gratiolet’s description of the functions of the muscles, and for
which I am indebted to the author himself, who has kindly therein distinguished the effects
of s¢multaneous action and those of the alternate action ; and for the assistance of the
reader Mr. Hancock’s names have been added within brackets.

1. MusciEs préappucTEuRS (posterior adductor) and Ppos-appucrEURS (divaricators).

a. Simultaneous action —The energetically drawing together the valves in their whole
length.

b. Alternative action.—When the préadducteurs contract themselves alone, they close
the shell in front and make it gape behind. When the _post-adducteurs
contract alone, they close the shell almost completely behind and make it open in
front.

2. MUSCLES PEAUSSIERS VERTICAUX (posterior parietal muscles).

a. Simultaneous action.—They depress the body behind, cause the internal fluid to flow
towards the arms, and consequently come strongly in aid of the action of the
“muscles post-adducteurs.”’

3. MUSCLES OBLIQUES TRANSVERSALEMENT, muscles croises of Cuvier (posterior adjustors)

a. Simultaneous action.—They energetically draw together the valves,
6. Alternative action.—Taking for a fixed pomt the valve which I call the superior

204. BRITISH CARBONIFEROUS BRACHIOPODA.

(ventral), the right muscle, causing a traction upon the opposite side of the inferior
valve, makes it deviate a little to the right by a sliding, the extent of which I
should not know, a@ priorz, how to measure. The double-cross muscle of the left
side, acting symmetrically, makes it deviate a little to the left.

A. MUSCLES OBLIQUES POSTERO-ANTERIEURS (anterior occlusor) ef ANTERO-POSTERIEURS
(central and external adjustors).

a. Simultaneous action—They draw the valves together energetically.

b. Alternative action—Supposing always the superior (ventral) valve as a fixed point
the “muscles postero-antérieurs acting from behind forward upon the inferior
(dorsal) valve, make it slide backward. ‘The muscles “ antero-postérieurs ’’ acting
from the front backward upon the inferior valve, make it slide forward.

N.B.—If one admitted an alternative possible between the longitudinal oblique muscle
of the right side and the left side, their movements would evidently come in aid
of those of the cross muscles.

5. Muscirs p&poncunatres (peduncular muscle) e/ MUSCLES MARGINAUX.

‘These muscles leave also their traces upon the shell. The first erect (adjust) the body
upon the peduncle, and that in two ways—the first by a direct action, in the second place
by causing the fluids which fill the internal cavity of the peduncle to ebb into the body.
The second act exclusively upon the border of the great pallial lobes.

It will therefore be seen, from what has been stated, that, although anatomists agree
as to the shape and position of the muscles, they entertain different views respecting some
of their functions. ‘Thus, Mr. Hancock objects entirely to the notion of the sliding of the
valves in different directions over each other by the aid of the adjustors (protractor sliding
muscles of Woodward’), a theory first propounded by Cuvier and Owen; while Dr.
Gratiolet believes that the cross disposition of certain muscles, whether from behind
forward or whether from right to left, would Jead one to imagine a compensated antago-
nism from which equilibrium would result during the simultaneous contraction of all the
elements; and that the oblique muscles transversely crossed of Cuvier, his ‘“ muscles
obliques postero-antérieurs” and “antero-postérieurs,’ were employed in the sliding
action of the valves. Mr. Hancock, on the other hand, observes that in Crania, where
the muscular system is arranged after the plan of Zingula, there exists xo sliding move-
ment, and that Mr. Lucas Barrett, who has seen Crania alive, has distinctly stated that
‘the valves open by moving upon the straight side, as on a hinge, without sliding of the
valves ;” but it would be out of place and presumptuous were I to dwell any longer upon

! According to Mr. S. P. Woodward, Lingula would possess a pedicle muscle ; three adductor muscles,

the posterior pair combined ; two pairs of retractors, the posterior pair unsymmetrical, one of them diyid-
ing; and two posterior sliding muscles.

LINGULA. 205

this controversed question, my object having been attained if I have been able to lay
before the geological and paleontological reader the views of two such eminently dis-
tinguished anatomists as Mr. Hancock and Dr. Gratiolet, and no doubt time will prove
which is the correct interpretation ; for now that the question at issue has been made
known, it will not be difficult for some observer who may happen to be where Lingula
is found alive to notice whether or not the valves do slide upon one another. We will
now conclude the little we had deemed necessary to say of the animal by observing that
the so-termed oral arms are not supported, as in many of the articulated genera, by a more
or less complicated system of lamelle; that they are fleshy, with their spires directed
towards each other.

After much examination I have reduced the so-termed species of British Carboniferous
Lingule to four, viz., ZL. squamiformis, L. mytiloides, L. Credneri (which may possibly
be a variety of Z. mytiloides), and L. Scotica.

Lineuna squamirormis, Phillips. Pl. XLIX, figs. 1—10.

LINGULA SQUAMIFORMIS, Phillips. Geol. of Yorkshire, vol. ii, pl. ix, fig. 14, 1836.
— _ Portlock. Report on the Geol. of Londonderry, &c., pl. xxxii,
fig. 5, 1843.
— _ M‘Coy. British Pal. Foss., p. 475, 1855.
— — Dav. Mon. of Scottish Carb. Brach., pl. xi, fig. 14, 1861.

Spec. Char. Shell longitudinally oblong, one third or less longer than wide, with
sub-parallel sides, the broadest towards the anterior extremity, the frontal margin
assuming either a very slight inward or outward curve. ‘The anterior portion is gradually
curved on either side, the beak being rounded or but slightly angular at its extremity in
the dorsal valve, with a thickened margin, tapering, pointed retrally at its termination in
the ventral one, which is consequently so much longer than the opposite valve. The
valves are slightly convex, but somewhat depressed along their middle. In the dorsal one
there exists a small apex close to the rounded margin of the beak, and from which usually
radiate three small, rounded ridges, separated by shallow sulci. The external surface in
both valves is covered with numerous fine, concentric striae, or lines of growth, giving to
the shell a beautifully and delicately sculptured appearance, for the minute plications of
growth succeed each other with much regularity, while some stronger lines or interruptions
of growth are produced at variable distances. The internal muscular impressions are
similar to those already described, the occlusor and external adjustors of Hancock being
especially observable. Dimensions variable ; two British examples have measured—

Length 19, width 13 lines.

We) ere Ome ss

Obs. This is a common species in certain Scottish strata and localities, and is found

likewise in England and in Ireland, and can be distinguished from its congeners by shape

206 BRITISH CARBONIFEROUS BRACHIOPODA.

and sculpture, although the Silurian Ziagula granulata of Phillips approached nearest to it ;
this last is, however, usually less elongated, and does not present those radiatory ridges
which are generally, but not always, observable in the Carboniferous species.

In his work on ‘ British Paleozoic Fossils, Prof. M‘Coy concludes his description
of Z. squamiformis by stating that ‘‘the wide, short, oblong form of this species easily
distinguishes it from the others in the upper Paleozoic rocks. ‘lhe more elongated, narrow,
oblong species, well figured in Portlock’s ‘ Geological Report,’ tab. xxxu, fig. 5, under this
name, might be called Z. PorHocki (M‘Coy). Its proportional width is only 55-100th.
in the long, and 60-100th in the short valve.” But specimens connecting the narrow and
the wider varieties are so numerous that I could not admit the two extremes as distinct
species, besides which, Phillips’s original example is perfectly similar to many of the
Scottish examples of the species, although not very correctly figured in the ‘ Geology of
Yorkshire,’ and from which circumstance may have led some to doubt the identity.
Phillips’s specimen (fig. 1 of my plate), which may be seen im the British Museum, con-
sists of a shell and counterpart, or rather the shell is equally divided between the two
sides of a split nodule, so that neither of them show the true structure. When the shell is
removed the matrix shows regular, concentric striz, similar to those above described, but
elsewhere only fractured lines of lamine and radiating striz. The nodule is black, and
the shell dark and pyritous. Z. sguamiformis has sometimes attained comparatively large
dimensions ; thus, in a coaly shale intercalated between bands of ironstone at one mile to
the north of Glasgow millions of specimens may be seen in a crushed or distorted con-
dition, but of which some examples, when perfect, measured about one inch and a half in
length. Mr. Rodwell discovered also a specimen one inch two lines in length in a shale
at about a mile to the east of Bally Castle (on the north coast of Antrim), but the shell does
not usually attain such large proportions. In England it is stated by Prof. Phillips to
occur at Bolland; it is found also at Lemmington, Northumberland. In Scotland it occurs
at Raes Gill, at 341 fathoms below “Ell Coal,” 343 at Hall Craig, 317 at Braidwood
Gill, 354 at Langshaw Burn; it is found also at Hall Hill, near Lesmahago; in Ren-
frewshire at Orchard Quarry, Thornliebank ; in Dumbartonshire at Netherwood, near
Castlecary ; in Stirlmgshire in the Mill Burn beds, Campsie main limestone and Corrie-
burn beds. It is also found at Bishopsbriggs, three miles north of Glasgow; in Had-
dingtonshire at Cat Craig, near Dunbar; in Edinburghshire at Wardie (Western Break-
‘water, Granton); and occurs also in Fifeshire and the Berwickshire coast. In Ireland it
it has been found to the east of Bally Castle (north coast of Antrim), Leam, Fermanagh,
Enniskillen (in shale), &c.

LINGULA. 207

Lineuna Scorica, Davidson. Pl. XLVIII, figs. 27, 28.

Linauta Scotica, Dav. Mon. of Scottish Carb. Brach., pl. v, figs. 36, 37, 1860.

Spec. Char. Shell of an elongated triangular shape, tapering at the beak, slightly
rounded laterally and in front. The valves are slightly convex, but much compressed,
while the entire surface is covered with numerous minute, concentric striae, with still wider,
flattened interspaces. Interior tnknown. Dimensions variable; two examples have

measured—
Length 15, width 123 lines.
le K
” G3, »” 0 »

Obs. This remarkable species, which has at times exceeded the proportions above given,
is easily distinguished by its triangular shape, tapering sides and beaks, as well as by the
delicate and peculiar sculpture which adorns its surface. In shape it approaches to certain
exceptional examples of Phillips’s Zengu/a cuneata, but the Carboniferous and Silurian
species cannot be confounded.’

L.. Scotica Nas not been hitherto discovered either in England or in Ireland. In
Scotland it occurs at Gare, in Lanarkshire, at 239 fathoms below the “ Ell Coal,” and
from which locality it has been known to a friend in Carluke for upwards of thirty years.
My attention was, however, first directed to the shell by Mr. Young, of the Hunterian
Museum, Glasgow, who had been struck by its peculiar triangular appearance, and it was
subsequently discovered at Robroyston, north of Glasgow, in beds upon a similar horizon
to those of Gare, while the larger examples were procured by Dr. Slimon from Hall Hill,
Auchenheath, and Coalburn, Lesmahago, about 300 fathoms below “ Ell Coal.’

Lineuna mytitowss, Sowerby. Pl. XLVIII, figs. 29—36.

LINGULA MYtILOIDES, Sow. Min. Con., tab. xix, figs. 1, 2, 1812.
— ELLIPTICA, Phillips. Geol. of York., pl. xi, fig. 15, 1836.
— marGINaTA, Phillips. Ib., fig. 16, 1836.
—= PARALLELA, Phillips. Ib., figs. 17—19, 1836.
= MYTILOIDES and L. PARALLELA, Portlock. Report on the Geol. of London-
derry, &c., pl. xxxii, figs. 6—9, 1843.
= — De Koninck. Desc. des Anim. Foss. de Belgique, pl. vi, fig. 9,
1843.
-— — Dav. Mon. of Scottish Carb. Brachiopoda, pl. y, figs. 38,
43, 1860.

1 T possess also an American Lingula from the Pottsdam Sandstone of the Falls of St. Croix,
Minnesota, which is stated by Mr. Worthen to be the oldest American species of the genus. In shape it is
very similar to Z, Scotica, but differs from it in sculpture, as well as in the convexity of its valves.

208 BRITISH CARBONIFEROUS BRACHIOPODA.

Spec. Char. Shell very variable in shape, but usually more or less regularly elliptical
or ovate, with its greatest width either towards the posterior or anterior extremity. Its
sides are also sometimes nearly parallel and rounded in front, but both front and beaks
are in some examples about equally and regularly elliptically attenuated. ‘The valves are
generally gently convex, and most elevated along the middle, where there exists likewise a
flatness, which becomes gradually wider as it extends from the apex of the beak to the
front, the lateral portions of the valves sloping rather abruptly on either side, while the
surface is marked at intervals by a greater or smaller number of concentric ridges or lines
of growth. Interior unknown. Dimensions variable; three British examples have
measured—

Length 10, breadth 53 lines.

» Gai iss PO 2 Ls
Se ttrableg: SPATE eos

Obs. After the examination of a considerable number of specimens, it has appeared
to me that Z. parallela and L. elliptica are only slight variations in shape of Sowerby’s
L. mytiloides ? Some paleontologists will, however, probably differ with me in this con-
clusion, and may prefer retaining Z. mytiloides and L. parallela as separate species, and I
should be glad to adopt their views if they can point out the characters by which the two
can be distinguished. It will, perhaps, be as well, therefore, to reproduce the original
description and figures. Sowerby describes LZ. myti/oides as follows :

“‘Ovate, anterior end slightly truncated ; beak indistinct. Nearly an inch long, and
three fifths wide ; the older shells are flattened towards the front, with rather a straightish
edge. Shining, and of a grayish-blue colour.

«These are mostly found in pairs at Wolsingham, in the county of Durham, in a dark-
coloured limestone. I am told they are sometimes larger than the figure. They are pre-
served so well that they have the appearance of a recent mussel.”

Phillips describes his species as follows :

“ L. elliptica.—Long, elliptical, acuminated retrally, surface with delicate, radiating,
and concentric lines. Ashford, in Derbyshire.

“ [. marginata.—Very oblong, with parallel sides, truncate in front, rounded retrally ;
edges of the valves turned up; slight mesial ridge on a flat space; small, oval hollow, fine
radiating and concentric lines. Bowes.

“ [. parallela.—Magnified views of a species which seems different from the last by its
rounded front and equally convex surface. Northumberland.”

Besides the English localities above given I have seen specimens from the Carboniferous
shales of Brakewell and Ashford, in Derbyshire ; Denwich, Northumberland. In Scotland
it occurs abundantly in slaty ironstone in the parish of Carluke, in Lanarkshire, at 160
fathoms below the “ Ell Coal,” 239 at Gare, 300 at Mashock Burn, 237 at Raes Gill,
Braidwood, and Langshaw Burn, 371 at Kilcadzow. It occurs likewise at Hall Hill, near
Lesmahago, Capelrig, East Kilbride; Calderside and Auchentibber, High Blantyre ;

LINGULA. 209

Bishopbriggs and Robroyston, north of Glasgow. In Renfrewshire at Orchard Quarry,
Thornliebank. In Ayrshire at West Broadstone, Beith. In Stirlingshire at Craigenglen
and Corrieburn. In Fifeshire, at Craig Hartle, &c. It has also been found along the
Berwickshire coast, and at Marshall Meadows, three miles north of Berwick. In
Ireland it has been found in Tyrone, Desertcreat, also at Clogher (Pollock). On the
Continent it has been described by Prof. de Koninck, from Visé, in Belgium.

Lineuia Crupnerti, Geinitz. Pl. XLVILI, figs. 38—40.

LinGuLa CREDNERI, Geinitz. Versteinerungen der Zechteingebirges, pl. iv, figs. 23—
29, April, 1848.
— — M‘Coy. British Paleozoic Fossils, p. 474, 1855.
= — Kirkby. Proceedings of the Geol. Soc., vol. xvi, p. 412, 1860.

Spec. Char. Shell small, oval, occasionally oblong, with the posterior end acuminated
valves gently convex ; marked with concentric lines of growth. Interior unknown. Length
3, width 24 lines.

Obs. Is this shell specifically distinct from Z. mytiloides ? Might it not be a small
variety of the last-named shell? Indeed, I would hardly venture to positively assert that it
is specifically distinct. Until March, 1860, Z. Credneri was known only from the “ marl
slate” and the lower beds of the compact limestone of the Permian system, but Mr.
Kirkby informs us that the shell occurred to him as a Carboniferous species at Ryhope
Winning, near Sunderland, in the summer of 1858; that he observed it first in a thin bed
of dark shale, at a depth of 951 feet from the surface, or 592 feet from the base of the
overlying Permian strata, though in this bed it was exceedingly rare ; but that he found it
more plentiful in a thick stratum of gray shale just above the bed already mentioned.
That from the first (to use his own expression) he was struck with the resemblance of
these Lingule to the Permian species, Z. Credneri, and that his opinion was only strengthened
by the acquisition of a full suit of specimens, and which he submitted to Mr. Hancock’s
and my own examinations. :

There is no essential difference (he adds) between the Permian and Carboniferous
specimens. ‘The form of both is nearly oval ; the Carboniferous specimens have the median
elevation more prominent than those of the marl state, but that in this respect they only
approach more closely to the Permian example from the Kupsfer Schiefer, the German
equivalent of the marl slate, and that in no respect do the Permian examples differ from
the Carboniferous specimens more widely than do individuals of the same series from
each other.

27

210 BRITISH CARBONIFEROUS BRACHIOPODA.

Lineuta tation, M‘Coy. Pl. XLVIII, fig. 37.
Linevta LatTior, M‘Coy. British Paleozoic Fossils, pl. 1i1.D, fig. 33, 1855.

Spec. Char. “ Broad-ovate anteriorly, gradually acuminated posteriorly ; moderately
convex towards the beak, very gradually flattened towards the margins ; sides meeting at
the beak at an angle of about 75°; front wide, semi-elliptically rounded ; greatest width at
about the middle of the length, whence the posterior end is rapidly narrowed to the
beak. Surface with fine, sharply defined, strong, close, elevated, obtuse, concentric striz,
slightly irregular from occasional branchings and interruptions; crossed in parts by
longitudinal microscopic strize. Length 43 lines, proportional width 3%.” (M‘Coy,
p- 475.)

Obs. I have never seen this so-termed species, although stated by Prof. M‘Coy to be
not very uncommon in the black limestone over the main limestone of Derbyshire. It is
therefore provisionally given on the authority of Prof. M‘Coy, and until the species? may
have been completely studied.

1

(0).

PLATE XXVII.

CARBONIFEROUS SPECIES.

Streptorhynchus crenistria, P/c//ips. Carboniferous limestone, Kildare, Ireland.

2)

29

>)

23

2)

var. senilis, Pdellips. Vig. 2. The original specimen,
C. limestone, Bolland. — British Museum.

From Park Hill, Longnor, Derbyshire. Museum
of Practical Geology.

A fragment of dorsal valve, showing the cardinal

process and dental sockets.

var. Kelli, dJ/‘Coy. The original example, C.
limestone, Monaghan, Ireland.

var. cylindrica, J/‘Coy. ‘The original specimen, from
Arenaceous limestone of Castle Espie, Comber,
Ireland.

var, quadrata, J/‘Coy. The original specimen, Calp
of Ballintrillick, Bundoran, Ireland. 8, 9, 10.
From Sir R. Griffith’s collection.

Ww We st imir

Tho® Davidson del. & ith

“ve

| = a

PLATE XXVIII.

CARBONIFEROUS SPECIES.

Fig.
1 to 6. Strophomena analoga, P/illips. Different specimens from the Carbo-
niferous limestone of Kildare, in
Ireland; Longnor, in Derbyshire; and
Corrieburn, Stirlingshire.
he A 3 var. distorta, Sow. Lanarkshire, Scotland.
8. 53 : A very young shell of the
same.
9. $5 ay Interior of the ventral valve, in which the foraminal
aperture is cicatrized.
10. 5) a Interior of the dorsal valve.
We i“ 3 Internal cast, seen from the front, showing the
vascular impressions (enlarged).
12. 5 i A fragment of the ventral valve, showing the
position of the foraminal aperture.
13. 3 a The same, seen from the exterior, showing the
foramen.
14. Orthis Keyserlingiana, De Koninck. From the Carboniferous limestone
of Settle, in Yorkshire.
15. Orthis? antiquata, PAd//ips. From the figures in the ‘Geology of Yorkshire.’

15°°°4, Enlarged representations, drawn
from the original specimens, Bolland.
British Museum.

/

Geetaorecr henteriaye OK ky

4 Som

it
i

tN ese nian,
weenie wrote

Ciaceemease nen,

Tho Davidson del & lith

Fic.

IF

6,

~

PLATE XXIX.

CARBONIFEROUS SPECIES.

Orthis resupinata, J/artin. From the Carboniferous limestone of Bolland.

2)

2)

be)

29

22

3?

British Museum.
A very large example from Yorkshire.
A globose variety from Withgill, in Yorkshire, and col-
lection of Mr. Parker, of Manchester.
Another example, seen from the front.

var. gibbera, Portlock. From the lower limestone of
Cornacarrow, Enniskillen, and collection of Sir R.
Griffith.

var. connivens, Phillips. Carboniferous limestone of
Little Island, near Cork, Ireland, and collection of
Sir R. Griffith. |

|
i

uN)
NN

l

Tho’ Davidson del & lith

WWest tmp

Via.

dD.

9) 99
6, 7, 8, 9. Orthis Michelini,

10.

ay

13.

14,

Ly

PLATE XXX.

CARBONIFEROUS SPECIES.

Orthis resupinata, Martin. Carboniferous limestone, Millecent, Ireland.

9 be)

»? 2?

PP) 29

2? 2)
29 oe)
i] 2?

Streptorhynchus

2?

2)

1’. Portion of the surface, enlarged.
Interior of the dorsal valve, Derbyshire.

Interior of the ventral valve. a, Occlusor; rR, divaricator,
muscular impressions. Both 2 and 3 belong to the
same specimen.

Interior of the dorsal valve. a, Adductor or occlusor mus-
cular impressions ; 7, cardinal process. Carboniferous
shales, Ulverston, Lincolnshire.

Interior or ventral valve, shales near Settle.

I? fveillé. 6. From the Carboniferous shales of Clat-

tering Dykes, Malham Moor, Yorkshire.
7. From shales, Gateside, near Beith,
Scotland. 8, 9. From Carboniferous
limestone, Millecent, Ireland.

Interior of the dorsal valve (enlarged). 7, Cardinal process ;
A, adductor or occlusor muscular impressions. Gateside,
Ayrshire.

Interior of the ventral valve (enlarged), same locality. a,
Adductor or occlusor ; R, cardinal or divaricator, muscular
impressions. Mr. Hancock is of opmion that the upper
portion of this impression, or that nearest the beak, may
belong to the ventral adjustor, and that Nn may also

ce) . .
perhaps be caused by the pedicle. 0, Ovarian spaces.

? Carboniferous limestone, Settle, Yorkshire. A similar shell

to this is described under O. Michelini by Prof.
de Koninck, in his work on the ‘ Animaux fossiles
de la Belgique,’ pl. xii, fig. 8, but was afterwards
believed to be, perhaps, different. Having examined
many examples, I am disposed to consider it only a
slightly modified condition of L’Eveillé’s species.

crenistria, var. senilis. A very globose example, from the

Carboniferous limestone of Bowertrapping, near
Dalry, in Ayrshire, and collection of Mr. J.
Thomson.

. var. senilis (deprived of its outer surface or sculp-
ture), From the Carboniferous limestone of
Settle, Yorkshire.

3 This is the valve described as Leptena anomala,
Sow., in pl. 615, fig. 1’ (not *’or “) of the ‘ Mine-
ral Conchology,’ and as Strophalosia striata
by Prof. Morris, at p. 155 of his ‘ Cata-
logue; but an attentive study of the
specimen and of other similar examples has
convinced me that it is none other than an
imperfect, contorted valve of S. senzlis, of
which the outer layer or sculpture has been
obliterated. ‘Traces of the striae may, however,
be noticed here and there upon its surface.

Davidsom del. & lith

)
. f

Or

SJ

PLATE XXXI.

CARBONIFEROUS SPECIES.

Productus sub-levis, De Koninck. Stated to be from the Carboniferous lime-

stone near Leck, in Staffordshire (but
probably from Clitheroe, in Lancashire).
Coll. of Dr. Bowerbank.

4 From the Carboniferous limestone of Llangollen. Museum

of Practical Geology, London.
plicatilis, Sow. From the limestone of Longnor, Derbyshire.
Museum of Practical Geology.

_ From the limestone of Settle, in Yorkshire.

3 Internal cast of the ventral valve, from Longnor, in
Derbyshire, showing the position of the adductor and
divaricator muscular impressions.

mesolobus, Phillips. A remarkably circular example from the
Carboniferous limestone of Settle, in
Yorkshire.

Two specimens of the more common shape, from

Yorkshire.

>

* From the Glarat limestone, Campsie, Stirlingshire,
Scotland.

i
fi
{
i
|

ete

Tho® Davidson del & hth

: AWK? x wpradd

. ” a vi
ee ee
é dere :
— os

PLATE XXXII.

CARBONIFEROUS SPECIES.

Productus sub-levis? These are Prof. de Koninck’s figures of P.

”

2?

Christiani, but which appear to me only a slightly
modified condition of P. suh-levis ? Carboniferous
limestone, England (the exact locality is not given,
but was, perhaps, Clitheroe, in Lancashire.)

costatus, Sow. A specimen, with its spines, from Carboniferous
shales near Glasgow.

From Richmond, Yorkshire. Collection of Mr. S. Wood.
From the limestone of Settle, in Yorkshire.

Three different specimens from Richmond, in Yorkshire,
and Lesmahago, Lanarkshire, Scotland.

.. Interior of the dorsal valve, from Scotland, and collection
of Mr. J. Thomson.

A very fine, ribbed specimen, forming a passage into the
variety P. muricatus, from Howood, Renfrewshire,
Scotland, and collection of Mr. J. Thomson.

muricatus, Piillips. Fig. 10 is taken from the figure in the ‘Geology
of Yorkshire,’ 11 from the original specimen
found at Harelaw, and now in the York

Museum.
- From the limestone of Gateside, near Beith, in Ayrshire.

From Corrieburn, Stirlingshire, and collection of Mr. J.
Young.

- Another example from the same locality, enlarged.

W West imp

Tho® Davidson del.& hth

he

a (ed

Shige ae Ms
re

Mi ct Ni

Kia.

1 to 4.

8, 9.

HO, 11.

12.

13, 14.

15.

16.

PLATE XXXIII.

CARBONIFEROUS SPECIES.

Productus proboscideus, De Verneuil. Carboniferous limestone, Settle,

Yorkshire. I avail myself of
the present opportunity to
thank my zealous friend, Mr.
Burrow, for the liberal and
generous manner with which
he has presented me with his
best and, by me, figured speci-
mens of Producta.

_ ermineus, De Koninck. Carboniferous limestone, Settle, York-
shire.
RB Wrightii, Dav. Carboniferous limestone, Middleton, near Cork,

Ireland. Fig. 6 in the collection of Mr. J.
Wright, of Cork.

3 sinuatus, De Koninck. Fig. 8, nat. size; 8°*° enlarged. 9.
Enlarged view of the ventral valve, as
seen from the beak, to show the
position of the cardinal spines, We.
Carboniferous limestone, Settle, York-
shire.

a _ Internal casts of both valves, showing the position of
the adductor (a) and divaricator (R) muscular impres-
sions, as well as the reniform impressions (z).

e fimbriatus, Sow. Ventral valve, with its spines. Carboniferous
limestone, Settle, Yorkshire.
re a ‘wo examples deprived of their spines, from the same
locality.
¥ Xe 15%, interior of the dorsal valve; 15°, the same, viewed in

profile; 15’, the same specimen, seen from the exterior,
andshowing how the short spines are arranged inregu-
lar rows. Carboniferous shales, near Settle, Yorkshire.
mn aculeatus, Martin. From the original example. 16” A carefully
enlarged illustration. | Sowerby’s col-
lection, British Museum.

Fic.
ie Productus aculeatus. | Another similar example, but with a longer hinge-
line. Limestone, Settle.

18. “ - var. P. laxispina, Phillips. From the figure in the
‘Geology of Yorkshire.’ .
19: : 3 A large, older, and more spiny example, from Chrome
Hill, Longnor, Derbyshire. Museum of Practical
Geology.
20. " 3 P. spinulosa, Phillips (not Sow.) From the figure in the
‘Geology of Yorkshire’ (pl. vii, fig. 14).
21. - Youngianus, Dav. From the Carboniferous limestone of Corrie-
burn, Stirlingshire, and collection of Mr.
J. Young.
22. Fs - From Bolland.
23. : m From Settle, Yorkshire.
24, Rs tessellatus, De Koninck. From the Carboniferous limestone, Isle
of Man, nat. size.
20. re x A specimen deprived of its fringes, from Settle, in

Yorkshire.

W.West 1my

Tho® Davidson. del & Iith

15,°16,

20.

21.

PLATE XXXIV.

CARBONIFEROUS SPECIES.

Productus striatus, Fischer. Carboniferous limestone, Longnor, Derbyshire.

Museum of Practical Geology.
" Limestone, Settle, Yorkshire.
» As Derbyshire.

as of Malformations. Museum
of Practical Geology.

carbonarius, De Koniuck. Carboniferous limestone north of
Glasgow. Museum of Practical
Geology.
undatus, Defrance. Derbyshire. Collection of Dr. Fleming, of
Manchester.
5 Limestone, Poolwash, Isle of Man.

93 HA Settle, Yorkshire.

2» 33 Campsie, Stirlingshire.

3 P. tortilis, M‘Coy. Limestone, Tullanaguiggy,
Fermanagh, Ireland, and collection of Sir R.
Griffith.

tessellatus, De Koninck. Limestone, Kildare. British Museum.

Keyserlingianus, De Koninck. Limestone, Settle, Yorkshire.

arcuarius, De Koninck. Limestone, Settle, Yorkshire.

spinulosus, Sow. The original specimen. Linlithgowshire, Scotland,
and collection of the late Dr. Fleming.

- From the Carboniferous limestone near Lesmahago, and
collection of Dr. Slimon.

P. granulosus, Phillips. Carboniferous limestone, Settle,
Yorkshire.

5 Phillips’s figure of P. granulosus.

NVEXX PAIL

QuGa avoReTMOR

10.

15, 16.

ie

Ibisy IG)

PLATE XXXV.
CARBONIFEROUS SPECIES.

Productus latissimus, Sow. Carboniferous limestone, Dalry, Ayrshire.

“ “3 s Derbyshire. Collection of
Dr. Fleming, of Manchester.

‘Interior of the dorsal valve, from near Carluke, in
Lanarkshire.

Interior of the ventral valve, from Broadstone, near
Beith, Ayrshire, and collection of Mr. J. Armstrong.
longispinus, Sow. From the original example. West Lothian, and
collection of the late Dr. Fleming.

Ventral valve, with its elongated spines.

From Yorkshire.

From Craigie, near Kilmarnock, and collection of Mr.
J. Thomson.

9* Interior of the ventral valve (enlarged) ; 9” interior
of the dorsal valve. From the Carboniferous shales of
Capelrig, Lanarkshire, Scotland.

Interior of the dorsal valve. From shales under the main
limestone, Campsie, Stirlingshire, and collection of .
Mr. J. Young.

f > From East Kilbride, Lanarkshire.

3) 33

3) 29

3°

4 From the original example of P. Memingii, Sow. West
Lothian, Scotland.
- . Specimens in Arenaceous limestone, from Rutcheugh,
Northumberland.
A 4 var. P. lobatus, Sow. From Capelrig, Lanarkshire.
% var. P. sefosa, Phillips. From the original figures in

the ‘ Geology of Yorkshire.’ These are certainly only
different states of P. longispinus.

a .. var. P. spinosus, Sow. These figures are drawn and
slightly restored from the original example in the
collection of the late Dr. Fleming, Scotland.

,; % Two exceptional shapes of P. Jongispinus, from
Carboniferous shales near Carluke, in Lanarkshire.

ar KA
Wii”

May rat
FeGF)

Tho® Davidson del. & lith WWest imp

)

any
r

it

PLATE XXXVI.

CARBONIFEROUS SPECIES.

Fic.

We Productus humerosus, Sow. 1%. Internal cast of the ventral valve, from the Car-
boniferous magnesian limestone of Breedon,
Leicestershire. Museum of the Geological
Society. 1’. Interior of the ventral valve (a
portion of the beak being removed to show the
muscular impressions), from a gutta-percha
impression. .

2. ‘ Internal cast, from the same locality. 2 shows
the interior of the dorsal valve and beak of
ventral one; 2” the ventral valve, viewed in
profile.

3 a persouatus, Sow. From the original internal cast. The specific
claims of this so-termed species cannot be
decided, on account of the imperfection of the
material at our command. Kendal, West-
moreland. British Museum.

4, cora, D’ Orbigny. Carboniferous limestone, Settle, Yorkshire.

West 1mip

W

ThoS Davidson del. &]ith

|
|

PLATE XXXVII.

CARBONIFEROUS SPECIES.

Fic.

i Productus giganteus, Jfartin. Interior of the ventral valve, from which a por-
tion of the beak has been removed, so as to
exhibit the umbonal cavity. a and c, Adduc-
tor or occlusor ; R, cardinal or divaricator ;
muscular impressions ; 1, cavity occupied by
the spiral arms.

ww

Interior of the dorsal valve. 5, Cardinal process ; A, adductor
or occlusor, muscular impressions; Ww, projections to
which Mr. S. P. Woodward supposes the oral arms
to have been attached (?); x, reniform impressions ;
z, eminences corresponding to the hollows (1) in the
ventral valve.

x Hinge-line and cardinal process of dorsal valve.

Qu
.

These drawings are taken from valves belonging to
the same individual, which was obtained from the
Carboniferous limestone Ilangollen, and is in the
Museum of Practical Geology. It is one of the most
instructive specimens which I have hitherto examined.
The cardinal process was, however, so much imbedded
in the matrix that it could not be developed, so that
the deficiency was completed from another example in
the British Museum.

A. 5 e Ideal section or both valves (slightly improved) from the
figure published by Mr. 8S. P. Woodward, at p. 233
of his ‘Manual of the Mollusca.’ The letters refer to
the same parts in the other specimens.

SIEGE

Sig

ppl
saetgs
eth

aoe

PLATE XXXVIII.
CARBONIFEROUS SPECIES.
Productus giganteus, Martin. A very large example, from the Carboniferous

limestone of Derbyshire, in the collection of

Prof, ‘'ennant.

aos

wes

Peron

Hic
;

ay

Nr

;

Sy

hs

"eg

Tho® Davidson del. et hth

PLATE XXXIX.

CARBONIFEROUS SPECIES.

Fie.

ie Productus giganteus, Martin. Dorsal valve and beak of ventral one. Car-
boniferous limestone near Richmond, York-
shire, and collection of Mr. E. Wood.

2. x 7 A smaller specimen. Same locality.

3 5 - A very circular variety.

4. e ‘s An evenly convex variety, P. maximus, M‘Coy. Carboni-

ferous limestone near Cork, Ireland.

De A 7 A young example. Yorkshire.

ALO ta yn
oe

ho’ Davidson del et hth

1

Fie.

4 to 8.

PLATE XL.
CARBONIFEROUS SPECIES.

Productus giganteus, Martin. Internal cast of the ventral valve, from the Car-
boniferous limestone of Lowick, Northum-
berland, and from the same specimen which
was represented under another aspect
in Professor King’s ‘ Permian Monograph.’
The letters are the same which have
been made use of in the interior, PI.

XXXVII, fig. 1.

var. P. Hdelburgensis, Phillips. From a specimen in the
Carboniferous limestone of Yorkshire.

A decorticated specimen or cast, from the Carboniferous
limestone of Thornton, Wensleydale, showing a peculiar
interruption and bifurcation of ribs.

var. ? P. hemisphericus, Sow. From the Carboniferous
limestone of Craven, in Yorkshire, where the shell occurs
by millions.

From one of the original and typical specimens of P. hemi-
sphericus, Sow., from the mountain limestone of Mynidd
Craig, near Kidwelly, in Carmarthenshire.

4
ee
Qi Ay e
‘ _¥
* o
-§ oe

=

PLATE XLI.

CARBONIFEROUS SPECIES.

Fic.

i Productus pustulosus, Phz//ips. The original specimen, from the mountain lime-
stone of Bolland. Gilbertson’s collection,
British Museum.

ae . 5 A very large example, from the Carboniferous limestone
of Derbyshire. Museum of Practical Geology.

a - es From the Carboniferous limestone of Craven. Collection
of Mr. E. Wood,

Ae re % Interior of the dorsal valve, from the Carboniferous lime-
stone of Yorkshire.

D. , » Internal cast of the ventral valve, seen from the umbonal
portion. Shores of Lorgh Gill, County Sligo. Museum
of the Geological Society.

6. :; - This is the P. rugata of Phillips, not well represented in

the ‘Geology of Yorkshire.’ Bolland.

Tho® Dayidsan del &lith W.West amp

} \ a)
> a ay b,

dur

=

PLATE XLII.

CARBONIFEROUS SPECIES...

Fie

1,2. Productus pustulosus, P/z/lips. From the Carboniferous limestone of Kildare,
in Ireland.

3. 2 pe P. ovalis, Phillips, from the Carboniferous limestone of
Bolland.

A. = ss P. pyaidiformis, De Koninck, from the Carboniferous
limestone of Yorkshire.

D. - scabriculus, A/artin. From the Carboniferous limestone of Carluke,
Lanarkshire, Scotland.

6. ss - P. quincuncialis, Phillips. Carboniferous limestone of
Yorkshire.

7. » i A very large example from the Craven district, in York-
shire, and collection of Mr. E. Wood.

oh) s st Interior of the dorsal valve, showing the curiously divided
median ridge, from the Carboniferous shales of Lanark-
shire, Scotland.

9. cora, D’Orbigny. From a specimen showing the concentric

wrinkles sometimes ‘present in the dorsal valve. Derby-
shire ?

4

Tho®Davidson del &lith W West nap

Fic.

6.

oa

LO:

PLATE XLIII.
CARBONIFEROUS SPECIES.

Productus semireticulatus J/artin. From the Carboniferous limestone of Kildare.
]* A large spine.

5 5 A specimen agreeing with Phillips's P. pugilis, from the
Carboniferous limestone of Stirlingshire.

e Bi From the Carboniferous limestone of Nellfield, Lanark-
shire.

¥ * Portion of a ventral valve, showing a long spine zz situ.
Limestone, Kildare, Ireland, and Museum of Practical
Geology.

s is Profile of a specimen from Kildare.

Portion of a specimen (enlarged), im which a small,
but distinct, area and a pseudo-deltidium can be
perceived. Locality unknown, probably Derbyshire.
British Museum.

var. Martini, Sow. Carboniferous limestone, Settle,
Yorkshire.

From Park Hill, Longnor, Derby-
shire, and Museum of Practical
Geology.

Interior of dorsal valve, from
shales near Settle, in Yorkshire.

var. concinna, Sow. From the Carboniferous limestone of

Campsie, Stirlingshire.

”? )

A specimen of the same, to show
how the shell becomes at times
fractured.

wees

Sart 1 AVN Vedas mre

oe meee oe wena

L

ThoS Davidson, del et ith.

vu oni

ieell

oe ee

Fia.

Ol
.

14.

PLATE XLIV.

CARBONIFEROUS SPECIES.

Productus semireticulatus, J/artim. Interior of the dorsal valve, from the Carbo-

99

niferous shales of Calderside, E. Kilbride, Scotland.

. Enlarged fragment of another specimen, from Redesdale,
Northumberland.
re Fragments (enlarged) to show the cardinal process, as seen

from the exterior of dorsal valve.

Interior of the ventral valve, from Calderside, E. Kil-
bride, Lanarkshire, Scotland. Beautifully preserved in-
teriors of both valves occur in a shale near Settle, in
Yorkshire.

margaritaceus, Pii//iys. From the Carboniferous limestone of Settle,

in Yorkshire.

The typical specimen, from Florence Court, and collection
of Prof. Phillips.

- A young shell, from Settle.

Phillips’s P. pectinoides. Carboniferous limestone, Bol-
land, Yorkshire.

2?

punctatus, Martin. From the Carboniferous limestone of Wensley-

dale, Yorkshire.

a From the limestone of Ayrshire, Scotland. 10” Spiny
surface, enlarged.

From Settle, Yorkshire.

A very elongated example, from the limestone of West
Broadstone, Ayrshire, Scotland.

a A young shell, from Bolland.

nh An oval variation, from Wensleydale, Yorkshire.

var. elegans, M‘Coy. Carboniferous shales of Craigen-
glen, Stirlingshire.

Interior of the dorsal valve, from shales near Settle,
Yorkshire.

Internal cast of the ventral valve, as seen from the beak.

9

fimbricatus? var. /aciniatus, M‘Coy. From the Carboniferous lime-

stone of Kendal, in Westmoreland.

on del et lth

=
Jayias

sT)
L

Fic.

52.

PLATE XLV.

CARBONIFEROUS SPECIES.

Chonetes? comoides? Sowerby. From the Carboniferous limestone,

Trefonen, south-west of Oswestry.
In the collection of Mr. G. W.

Ormerod, of Manchester.
“ Interior of ventral valve, showing the strong, articu-
lating teeth, from Llanymynech. Same collection.
rf Longitudinal section and weathered specimen, from
Tidenham Chase (Gloucestershire), near Chepstow.

comoides, Sow. A characteristic example, locality lost. Bristol
Museum.

Tho® Davidson,del et hth.

“7 |
és - Ay
Pe
7 mi = > 7
at ce oa
oem ak ~~

- ed i iy 7 ‘
9 | en

Fic.
lL.

3, 4.

Ot

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PLATE XLVI.

CARBONIFEROUS SPECIES.

Chonetes comoides? Sow. From the Carboniferous limestone of Bundoran,

2)

in Donegal, and collection of the Geological
Society.
papilionacea, P/i/iips. From Phillips’s original example. Carbo-
niferous limestone, Bolland. A portion
of one wing has been restored.

B From Carboniferous shales near Settle, in Yorkshire.
5’ A portion of the shell enlarged ; 0, orifices left
by the broken spines; P are pits left on the
cast by the asperities which covered the inner
surface of the shell.

. Internal cast, showing traces of the muscular
impressions, from Ireland.
Dalmaniana, De Koninck. From the Carboniferous limestone of
Settle, in Yorkshire.

|
|

r

CARBONIFEROUS. :

Ap

ige:

25

E
‘W-West, ump

Tho§ Davidson, del & lth.

13.
14.

6.

PLATE XLVII.

CARBONIFEROUS SPECIES,

Chonetes Buchiana, De Koninck. From the Carboniferous limestone of Settle,
in Yorkshire.

< x Variety with strong ribs, from the Carboniferous shales
of Malham Moor.

i z From Gare, Lanarkshire, Scotland. 3°°* Enlarged.

“i = A very large and transverse example. Rutcheugh, Nor-
thumberland.

re Ri Interior of the ventral and dorsal valves, enlarged, from

specimens found at Malham Moor by Mr. Burrow.

i var. interstriata. From the Carboniferous limestone of
Settle, discovered by Mr. Burrow. 7* Enlarged.

polita, M*Coy. From the Carboniferous shales of Craigenglen,
Stirlingshire, in Scotland, and collection of

Mr. J. Young. 8*° Enlarged.

,, Another example, from the same locality.
.. Prof. M‘Coy’s original figure.
Interior of the dorsal valve, from the Craigenglen beds, Stir-
lingshire, Scotland.

Hardrensis, Phillips. A typical example, from the Carboniferous
shales of East Barns, near Dunbar, in
Scotland. 12° Half of one of the valves,
carefully enlarged.

A more coarsely striated variety, from Settle, in Yorkshire.

P . Interior of the dorsal valve, enlarged, from the Carboni-
ferous shales of Calderside, Lanarkshire, Scotland, and
collection of Mr. J. ‘Thomson.

; ¥ Interior of the ventral valve, enlarged, from Capelrig, in

Lanarkshire.

Interior of the dorsal valve, corresponding to fig. 15.
Same locality, aud collection of Mr. J. Armstrong.

A young specimen, from Craigie, near Kilmarnock. Col.
lection of Mr. J. Thomson. 17° Enlarged.

A small specimen, from Settle. 18° Enlarged.

var. laguessiana, De Koninck ? From the Carboniferous
shales of Newton-on-the-More, Northumberland. 19%
Enlarged.

Fic.

21.

Chonetes Hardrensis. C. suleata, M‘Coy. From the original specimen, Are-

naceous slate, Bruckless, Dunkeneely, Ireland. Col-
lection of Sir R. Griffith.

C. volva, M‘Coy. From the original and other exam-
ples in the collection of Sir R. Griffith, Carboniferous
limestone of Millecent, Ireland.

A small variety, from the shales above the Hosie lime-
stone, South Hill.-Campsie, Stirlingshire, Scotland.

C. gibberula, M‘Coy. From the original figure.

C. subminima, M‘Coy. rom the original figure.

C. perlata, M‘Coy. From the original specimen, in
the collection of Sir R. Griffith.

serrata, J/‘Coy. From the original specimen, Carboniferous lime-

stone, Millecent, Ireland.

tuberculata, J/‘Coy. From the original specimen, Carboniferous

limestone, Millecent, Ireland.

Buchiana? or crassistria, JZ‘Coy. From the original specimen, Bun-

doran, Ireland.

papyracea, M‘Coy. From the original specimen, Ireland.

be

PAE

Fah
¢

a

*

PALMONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVII.

LON DOWN:

MDCCCLXI,

MONOGRAPHS

ON THE

BRITISH FOSSIL

Inge as di

FROM

THE OOLITIC FORMATIONS.

BY

RICHARD, OW EN, chon. 8:D Cake;

FOREIGN ASSOCIATE OF THE INSTITUTE OF FRANCE, ETC. ETC.

PART FIRST,
CONTAINING

SCELIDOSAURUS HARRISONIT AND PLIOSAURUS GRANDIS.

LONDON:
PRINTED FOR THE PALAZONTOGRAPHICAL SOCIETY.
1861.

Ah AME: be >

mM ; pe ines

A MONOGRAPH

FOSSIL DINOSAUR
(SCELIDOSAURUS HARRISONIL, Owsy)

OF THE

LOWER LIAS.

In the year 1858 a few fragmentary fossils of limb-bones were submitted
to my inspection by James Harrison, Esq., of Charmouth, Dorsetshire, obtained
from the upper part of the “lower Lias,” near that place. They included portions
of a femur and of a tibia, in which the texture of the wall and the size of the
cavity of the shaft showed them to have been parts of a Saurian of more terres-
trial habits than any of those which had been previously discovered in Liassic
deposits: traces, moreover, of the extent and direction of certain processes, although
broken away in the fossils, were discernible, which led me to suspeet they
belonged to a reptile allied to Zguanodon. I therefore briefly notified the fact
of a Liassic Dinosaur in my ‘ Paleontology, * and indicated the animal by the
generic name Scelidosaurus.¢ I propose, in the present monograph, to describe
these very interesting fossils as they have successively come under my observation,
and submit the proofs of the generic distinction and Dinosaurian affinities of the
extinct animal.

* Svo. ed., 1860, p. 258.
+ Gr. oxedis, limb, cavpos, lizard; from the indications of greater power in the hind legs than in
most Saurians.

1

2 FOSSIL REPTILIA OF THE

Femur. ‘Tab. I.

I may premise that the femur of the Jguwanodon is characterised by the deep
and narrow fissure dividing a compressed external trochanter from the head of
the bone, and by a process from the middle of the shaft, on the inner side,
opposite to the part where the “ third trochanter ” projects in some of the large
herbivorous mammals (Perissodactyla). Both these characters are repeated in the
specimen of the uncompressed shaft of the femur represented in Tab. I; but the
shaft, viewed sideways, as in fig. 3, shows a more decided sigmoid flexure than in
the Iguanodon, and the fissure between the great trochanter (ce) and the proximal
end of the bone (c) is relatively deeper. The exterior surface of the shaft is
smooth, and in the present fossil glistens, and is, as it were, bronzed by a thin
coating of pyritic salt. The proximal end of the bone (c) divided by the cleft
from the great trochanter (e) is subcompressed from side to side below the
swelling out of the head, and is extended from before backwards ; the head itself,
or articular end’ of the bone, has been broken or abraded away, showing a fine
cancellous structure at that part (fig. 3,c). The antero-posterior diameter of this
part is 6 inches; the transverse diameter, opposite the base of the outer trochanter,
is 3 inches 8 lines.

The fore part of the shaft (fig. 2) shows at its upper half a flattened, oblong,
rather rough surface (f) for muscular implantation. Below, and on the outer
side of this surface, is a rough, roundish, slightly prominent tuberosity (s), con-
tinued at its inner side into a ridge, which descends with a slight curve out-
wards on the fore part of the middle of the shaft of the femur, where it terminates
in a point at » These risings indicate the force of the large muscles acting upon
the limb, and by their insertions raising and drawing forward the femur. The
elongated base of the inner process (fig. 3, 4) becomes slightly narrower as it
descends ; its full extent is not recognisable, by reason of the wall of the shaft
being there broken away, exposing the medullary cavity (m). Behind the base of
the process is a large, oblong, rough ridge, indicating the extension of the surface
of attachment, behind and beyond the process itself, for a powerful muscle
depressing and drawing back the femur. [ do not find this character so well
marked in the femur of the Iguanodon. The homologous roughness is present,
without the process, in the femur of the Megalosaur. From the great trochanter
(c:) a narrow, rough surface, not projecting as a ridge, extends nearly straight
down the outer and back part of the shaft (fig. 1 0). Exterior to this surface is
an oval foramen (a), most probably for the passage of the blood-vessels and nerve
to the medullary cavity.

LOWER LIAS. 3

The transverse section of the middle of the shaft is nearly circular; the
thickness of the compact wall of the medullary cavity is here about one sixth of the
transverse diameter of the bone. I have not seen a bone of any other
Dinosaur indicative of more vigorous action of the hind limbs than the present
femoral shaft.

The foregoing interesting and instructive fossil was accompanied by the shaft
of a tibia of corresponding size, crushed and broken at both ends; it measured
18 inches in length and 2 inches 8 lines in diameter at its middle, the circum-
ference of the shaft there being 10 inches.

These proportions indicate a hind leg, longer and more slender, relatively to
the trunk, than in the Megalosaur, Iguanodon, or other Dinosaur with which
such comparison may be made. The bone being fractured across the middle of
the shaft, shows a large medullary cavity; the compact, bony wall does not
exceed 3 lines in thickness, the cavity itself being 1 inch 3 lines in diameter.

At the proximal end the antero-posterior expansion and its ridges have been
broken away. The bone gradually contracts, as it descends, to a subtriedral shaft,
with a triangular transverse section, two of the angles being rounded off, and
the third remaining, which was opposite the fibula. ‘The distal expansion has
been, in like manner, broken away; but its commencement shows the rise of an
anterior ridge in addition to the fibular one. I did not think it necessary to
figure this fossil, as I shortly after received from Mr. Harrison and Mr. Henry
Morris, F.R.C.S., of Charmouth, the subjects of the two following plates.

Parts of the Femur, Tibia, and Fibula forming the Knee-joint. Tab. U.

In the specimen figured from three views (figs. 1, 2 and 8) in this plate, the
lower half of the right femur and the upper half of the right tibia and fibula are
cemented by the matrix in the natural relative position in which they enter into
the formation of the knee-joint, when bent. This remarkable specimen inglicates
the tranquil state of the sea-bed or bottom after it had received the dead
carcass of the Dinosaur. No agitation or other external violence has displaced
the bones of the leg after the solution of the ligaments which tied them
together in the living animal; when the depth to which they had sunk, and
the consistency of the mud or clay bed, tended to retain them in their natural
position. The portion of femur preserved indicates a slight backward bend of
the shaft, which at the fractured part—probably a little below the middle of
the bone—presents an almost circular transverse section. The circumierence
here is 10 inches; the compact wall of the bone is 6 lines thick; the medullary
cavity 2 inches in diameter. A little below the fractured end, and 8 inches above

4 FOSSIL REPTILIA OF THE

the lower end, the shaft shows the termination of the inner process. From this
point the femur expands gradually, and chiefly in the transverse direction. Pos-
teriorly it becomes impressed by the popliteal cavity, which deepens and widens
to the upper and back part of the inner condyle; which, by its production towards
the outer condyle, contracts the lower end of the popliteal cavity transversely.
On the outer side of the distal expansion of the femur, the external wall is in
part broken away; but a shallow and narrow longitudinal impression is indicated,
terminating below in a rather shallow notch, which marks out the inner and
hinder part of the outer condyle from the outer part of the same condyle. This
notch corresponds with that between the tibia and fibula, and defines the portions
of the outer condyle assigned to those bones respectively. ‘The inner condyle is
rather flattened on the inner side (a). ‘The tibia is much expanded at the proximal
end, chiefly by an extension of the bone forward (fig. 1); it is slightly convex on
the inner or tibial side (e) ; a longitudinal prominence extends from the fibular side
of the expansion, near the fore part, answering to the ectocnemial process in the
bird’s tibia; the main expansion forms the procnemial process (figs. 1 and 2, p) which
has subsided to the ordinary level of the shaft about six inches down the bone.
The back part of the proximal end of the tibia (fig. 3) presents two almost hemi-
spheric protuberances (fig. 3, ¢, d@), side by side; they might be mistaken in a de-
tached bone for the backwardly projecting condyles of a femur, but are less deeply
severed. The outer tuberosity (¢) articulates with a slight depression in the con-
tiguous part of the fibula (7). The fore part of the proximal portion of the tibia is,
transversely, concave, exterior to the pro- and ecto-cnemial processes. The
fractured part of the shaft, eleven inches below the knee-joint, presents a full, oval
section, with the same proportion of compact bony wall to medullary cavity as
in the femur; the white spar filling the cavity (m) contrasts strongly with the
jet-black colour of the petrified bone (¢’). The transverse diameter of this part
of the shaft is 2 inches 3 lines; the fore and aft diameter is 2 inches 6 lines.

The fibula expands chiefly in the fore and aft direction at its upper end
(fig. 2,4), where it measures 5 inches across. Six inches lower down this diameter
has contracted to one of 1 inch 8 lines; eleven inches lower it measures 1 inch
3 lines, the transverse diameter being 9 lines. Seven inches from the proximal
end the fibula presents at its outer and back part a thick, longitudinal, rough ridge,
for the attachment of a muscle. It continues in contact with, and gets rather
behind, the tibia as it descends.

LOWER LIAS.

qr

Ungual Phalanx. 'Yab. LU, figs. 4, 5, 6.

The ungual phalanx transmitted with the foregoing leg-bones, from the
collection of Henry Norris, Esq., F.R.C.S., is somewhat intermediate in its
proportions between that of the hind foot of the Megalosaurus and that of
the hind foot of the Jgwanodon; it is less compressed than the former, less
depressed and flattened than in the latter. On one side of the base, near the
articular surface, it is impressed by a shallow, vertical canal (fig. 6, 7), extending
from the upper to the lower part of the bone. A median, low and _ broad,
vertical prominence extends from the upper half of the articular facet (fig. 5, 2),
giving a sub-crescentic figure to the cavity of the joint; the lower border
is straight to near the apex, which is slightly bent down (fig. 4). There are no
indications of lateral grooves and foramina for blood-vessels.

Bones of a young Scelidosaur. ab. U1.

Subsequently to the exposure and acquisition of the foregoing fossils an intel-
ligent quarry-man discovered, in the same member of the lower Lias, a collection
of small bones, of a delicate, friable texture, of which those comprised in Tab. III
were brought to Mr. Harrison, by whom they were kindly transmitted to me for
description. The collection included the centrum or body of a vertebra (figs. 1—4),
a left femur (figs. 5, 6), a considerable portion of a tibia (fig. 7), and fibula
(figs. 8 and 9), a tarsal bone (fig. 15), a metatarsal (figs. 10 and 11), and a proximal
phalanx (figs. 12—14). The long bones were much crushed, especially the femur.
This bone, therefore, appears to be thicker than it really was, being almost flat-
tened. The articular ends have been ina fibrous, unossified state, so that they
appear flatter or less prominent than they were in the recent bone. The external
trochanter (e) seems entire, and has not risen higher in relation to the head of the
bene than is shown in fig. 5. The internal process (¢) is similarly avell pre-
served, repeating the character of the herbivorous Dinosauria which is exemplified
in the Iguanodon. The outer condyle of the femur is longitudinally grooved for
the fibula. The medullary or unossified cavity of the shaft of the bone has been
more considerable, in relation to the compact shaft, than in the large femora pre-
viously described.

From the foregoing characters it may be concluded that the present femur
has belonged to a Dinosaur, allied to the Iguanodon, and to a very young indi-
vidual, and it most probably formed part of a very young or foetal Scelidosaur.

Fig. 7, Tab. III, is a crushed tibia, with the upper end much produced for-
ward and bilobed behind, as in that of the Scelidosaur, the lower end is wanting.

6 FOSSIL REPTILIA OF THE

It bears the same proportion to the femur as does the tibia in the specimen
figured in Tab. II.

The bone, with the shaft crushed flat, and with a sub-bilobed end (figs. 8 and 9),
having the opposite extremity broken away, more resembles a fibula than it does
a metatarsal bone.

The bone (figs. 10 and 11) presents the characters of a metatarsal at both its
articular extremities, and might well belong, by its general proportions, to the
same limb with the femur (fig. 5) and tibia (fig. 7) of Tab. TI. Fig. 12 gives a
side view, fig. 13 a back view, and fig. 14 a front view, of a proximal phalanx of
one of the tces of a foot of corresponding dimensions.

A tarsal bone (Tab. III, fig. 15) presents a peculiar form; one of the larger
surfaces (a) is impressed with a shallow cavity; it is separated from the opposite
surface, for two thirds of its extent, by a smooth, convex, apparently articular,
surface, broader at one end of the bone than at the other. The other third of the
marginal surface (4) presents a triangular, rather flattened, facet. The opposite
surface to a is also impressed by a cavity, bounded by a sharper margin, which at
one end is notched, so that two slight angular projections herg appear, as at
b, fig. 15.

The vertebral centrum presents one terminal surface flat, the other slightly
convex ; it belongs to the dorsal or lumbar series, all the processes having been
developed from the neural arch, which has separated from the sutural surfaces
shown in fig. 2. The sides of the centrum (fig. 1) are smooth, concave length-
wise, convex vertically, converging towards the lower border, but in a less degree
than in Jguanodon ; that border is consequently less narrow. The neural canal
sinks at the middle into the substance of the centrum (fig. 2). All the characters
of this part agree with the Dinosaurian nature of the young reptile which is
demonstrated by the femur (figs. 5 and 6).

From the texture, fragility, and evidences of incomplete ossification of the
bones represented in Tab. III, I infer them to have belonged to a very young
individual, and their occurrence in a marine deposit suggests many reflections.

To whatever extent the Saurian organization has been modified for terrestrial
life, that has been, in no instance, such as to suggest an inability to swim. On
the contrary, the disproportionate shortness of the fore limbs, even in the Igua-
nodon, leads to the suspicion that they might be short in reference to diminishing
the obstacles to propelling the body through water by actions of the strong and
vertically extended tail; and that, as in the living land lizard of the Gallopagos
Islands, called Amblyrhynchus, the fore limbs might be applied close to the trunk in
the Iguanodon, when it occasionally sought the water of the neighbouring estuary
or sea. One would suppose that the newly born or newly hatched young of a
Dinosaur might be safer on shore than at sea, or at least in waters which, like

LOWER LIAS. 7

those of the Liassic ocean, seem to have swarmed with carnivorous Enaliosaurs.
If the Dinosauria were ovo-viviparous, and produced but few young at a birth,
the remains from the lower Lias figured in Tab. III might be those of a foetus
borne by a gravid Scelidosaur to sea during an occasional excursion, and which by
some casualty had there perished, and become imbedded, with her progeny, in the
muddy bottom of the old Liassic ocean. I have not, however, been able to
obtain precise evidence of the proximity of the small bones above described with
any of the larger ones attributed to the Scelidosaurus, and bones of more than
one small individual might have been expected to occur in juxtaposition if they
had perished before birth. The analogy of the crocodile, moreover, would lead us
to expect that the newly excluded or newly born Scelidosaur would be of smaller
size than the individual indicated by the bones in Tab. ITI.

The Shull. Tabs. TV, V, VI.

The foregoing indications of a Dinosaur in the lower Lias excited speculation
as to whether it had been herbivorous, like the Iguanodon of the newer Mezozoic
beds, or carnivorous, like the Megalosaur, which has been traced from Wealden
down to the “great Oolite.” The structure of the femur pointed the former way,
but the proof which the dentition only could give was wanting.

The persevering encouragement afforded by Mr. Harrison to the workmen in
the Lias quarries has, however, been rewarded by the acquisition of the fine
specimen of a skull which forms the subject of Tabs. IV, V, and VI.

The teeth, in their close-set, thecodont implantation, relative size to the jaw.
degree of expansion, and general shape of the crown, resemble those ascribed to
the Hyleosaurus (p. 21, tab. viii, figs. 1—3, -‘ Monograph on Wealden Reptilia,
1857) ; but the crown presents the median longitudinal prominence and marginal
serrations which bring it closer to the Iguanodont pattern; and, in the degree in
which they depart therefrom, they still more closely resemble the teeth of the
Echinodon from the Purbeck,* which may prove to be a small kind, or young, of
a Dinosaur. They, however, present different proportions.

Referring, therefore, the skull in question to the Dinosaurian order, it sup-
plies most acceptable information as to the cranial structure of that group, which
no previous example from Oolitic and Wealden beds has been sufficiently perfect
to impart.

Of Iguanodon, Megalosaurus, and Hylzosaurus, portions of lower jaw, and
mere fragmentary bits of the upper jaw, palate, and basis cranii, are all that have
hitherto come to light. But the present specimen is the entire skull, wanting
only the fore end of the upper and lower jaws.

* € Monograph on the Fossil Lacertian Reptiles of the Purbeck Limestones, p. 35, 1858.

8 FOSSIL REPTILIA OF THE

The cranium has been slightly crushed and distorted by oblique pressure, due
to movements of the matrix after imbedding and petrifaction. The right halves
of the mid-frontal and nasal are depressed a little below the level of the left halves
of the same bones, and the right diverging branch of the parietal has been broken
from the rest of the bone, near the median line, and dislocated by the same pres-
sure from its union with the mastoid. The right ramus of the mandible, accom-
panying the movement of that side of the head, has been pushed so far below the
left ramus as to have its inner side brought into view in the profile of the skull
given in Tab. IV.

The occipital conforms to the Lacertian type in the proportions and direction
of the par-occipital; this process is long, narrow, straight, directed outwards,
compressed from before backward, and slightly expanded at the extremity, which
is applied to the back part of the mastoid and tympanic at the junction of those
bones. It has been slightly displaced, its end appearing on the left side at 4,
Tab. TV, with matrix intervening between it and the tympanic (2s). A part of the
exoccipital which projects backward to contribute to the formation of the condyle,
is exposed near the mass of matrix, including the atlas vertebra and nuchal
dermal bones.

The cranial part of the skull, posterior to the orbits, is shorter in proportion
than in the lizards, and resembles, in this respect, that of the crocodiles. The
parietal is short, and bifurcate behind, as in lizards. ‘The body of the bone, or part
between the temporal fossz, is subcompressed where it forms the smooth, concave,
inner sides of those depressions, which do not meet above, but are separated by a
narrow, flat tract; this might be converted into a ridge in older individuals. The
fore part of the parietal slightly expands where it is overlapped by the frontals.
Hach hind branch of the parietal extends outward and a little backward; its
pointed end is obliquely overlapped anteriorly by the inner branch of the mastoid,
completing therewith the hind boundary of the temporal fossa. The crushed and
dislocated state of the calvarium along its middle line does not permit the usual
evidence of a foramen parietale to be detected, but the appearances are against
such perforation being present. This foramen is not constant in modern lizards ;
the Scelidosaurus may agree with Cyclodus and Tejus in this respect. The parietal
bone, as a whole, plainly accords with the lacertian, not with the crocodilian, type
of that bone.

The mastoid (8) is a triradiate bone, forming the upper and hinder angle of the
cranium, from which one ray passes inward to join the parietal (7), a second ray
forward to join the post-frontal (Tab. V, 12), and a third ray downward to join the
tympanic (28). A fracture of the body of the mastoid, by which the anterior branch
is broken away on the left side (Tab. IV, 8), exposes a cancellous cavity, probably
forming part of the organ of hearing.

LOWER LIAS. 9

The two halves of the mid-frontal have been separated along the medial line,
and the right half depressed. The separation appears to have been at a suture,
as is certainly the case with the nasal bones; the medial margin of three fourths
of the left frontal show the jagged, sutural character. I conclude, therefore, that
the mid-frontal was divided, as in the Ichthyosaurus, and as in Varanus and
Lacerta proper; and that it was not a single bone, as in the Iguana and most
Lacertilia, and as it is in the Crocodilia. Fach half of the frontal in Scelidosaurus
is a long, inequilateral triangle, the medial being the longest side, the posterior,
which joins the parietal, the shortest ; the antero-external border is irregularly and
deeply notched, uniting with the post-frontal, super-orbital, pre-frontal, and nasal
bones ; it is excluded, as in Lacerta proper, by the large super-orbital bone (71)
from the orbit. ‘The outer surface of the frontal is sculptured by irregular lines
and grooves, but less deeply than in Crocodilus.

The post-frontal (12) forms the back and part of the upper border of the orbit,
uniting with the super-orbital, the frontal, and malar, and sending backward
an angular process to join the mastoid, completing the upper bar or zygomatic
arch of the temporal fossa. This arch had been broken away on the left side
(Tab. LV), but is preserved on the right side (Tab. V, 8, 12).

The pre-frontal presents a horizontal and a vertical portion; the former and
larger part is wedged between the frontal, superorbital, and nasal bones, the
descending plate joins the lacrymal (73), and touches the upper angle of the
maxillary (21). In the Crocodile the aspect of the whole outer plate of the pre-
frontal is upward; in some Lacertians the major part looks outward.

The nasal bones (15, Tabs. V and VI) unite above and behind with the
frontal (11) by a short border, obliquely and irregularly cut, to include the pointed
anterior ends of the lateral halves of the frontal; the nasals expand as they
advance, in union, first, with the pre-frontals, then with the maxillaries, where
they slightly decrease in breadth. ‘The mutilated fore part of the skull precludes
the determination of the relations of the nasals with the pre-maxillary, and of the
character of that bone. That of the outer plate of the nasals looks upward ; the
maxillary border is slightly bent down (15, fig. 2, Tab. V), and is overlapped by
the maxillary (21, ib.)

The fractured fore part of the skull in the above-cited figure shows the
superior thickness of the median and lateral borders of the nasals, the intervening
part being, as it were, channeled below for the air-passage; this has not here been
divided by any ossified vertical septum; the thickened palatal and alveolar parts
of the maxillary, as they bend toward each other, present a convexity transversely
to the nasal passage. ‘This is closed below, as it seems, by the vomer (13).

Of the hind part of the bony palate the pterygoid was brought into view by
removing the matrix between the diverging rami of the mandible. he body of

2

10 FOSSIL REPTILIA OF THE

the bone is in the form of a subtriangular plate, of 1 inch 7 lines extent along its
mesial border, which is slightly concave, receding from its fellow at the medial
line, or base, as in the Iguana; the apex extends outward, and a little downward
to abut against the fore and inner part of the ectopterygoid. From the hind
border near the base a long and narrow process is sent off to abut against the
tympanic. ‘There is no trace of teeth on the pterygoid, as in the recent Iguanas ;
the higher type of Saurian dentition is retained in Scelidosaurus.

The hind and probably main part of the maxillary, here preserved, is chiefly
remarkable for the horizontal ridge which nearly equally divides the outer or
facial plate of the bone into an upper and lower facet ; and this ridge is con-
tinued a little way below the orbit upon the malar bone. It corresponds with
the more strongly marked ridge in Ptychognathus and Oudenodon. ‘There is a
lower and slighter longitudinal prominence of the maxillary along the outer
alveolar plate. The maxillary reaches back beyond the middle of the orbit,
from which it is separated, as in other Saurians, by the malar and lacrymal
bones.

On both sides there is a small, unossified space between the maxillary and
lacrymal ; this corresponds with the larger vacuity in that part of the bones of
the face in the Pterodactyle, which is reduced to the present proportions in some
Teleosaurs, and becomes the functional nostril in the Ichthyosaur ; but I believe
that the true external nostrils of Scedidosaurus were included in the fore part of
the skull which has been broken away, and were, as in the Teleosaur, distinct
from the maxillo-lacrymal vacuities.

The orbits of Scelidosaurus are subcireular, almost vertical, looking outward.
Were the super-orbital ossicle in Crocodilia_enlarged and fixed by suture in the
upper scoop of the orbit, it would give a less vertical outlook to the eye than it
usually presents, especially in the skull of a crocodile from which that ossicle has
beenremoved. But the composition of the rim of the orbit in Scelidosaurus is open
to other homologies. The bone (71) may be compared with that wedged into the
upper and back part of the orbit in some lizards, between the frontal and post-
frontal, and by Cuvier regarded as a dismemberment of the latter element ; only in
Scelidosaurus it is extended forward to the pre-frontal, excluding the frontal from
the orbit. In Ichthyosaurus the post-frontal has a like forward extension and
junction with the pre-frontal, but it also passes backward to join the mastoid,
leaving to the bone at the back of the orbit a simple post-orbital function. In
Scelidosaurus the bone which joins the mastoid also sends down the post-orbital
bar to join the malar ; so that I find no nearer approach to the peculiar structure
of the upper part of the orbit in Scelidosaurus than the Crocodile would give with
a somewhat more fixed and developed superorbital bone.

The delicate lacrymal bone (73) appears to have been fractured on the left side

LOWER LIAS. 11

(Tab. IV); on the right side (Tab. V) it seems to be entire. The malar bone (26)
begins anteriorly, in a pointed form, between the lacrymal and maxillary, increases
in depth as it extends beneath the orbit, sends up a process which bifurcates to
receive the point of the post-frontal in the cleft (Tab. V, 27), and extends backward
and downward as a slightly convex and somewhat roughened plate, which articu-
lates by its lower convex, but somewhat irregular, border with the squamosal (27).
The posterior border of the malar presents a regular and well-defined, concave
curve. The chief peculiarity of the bone is its unusual vertical extent poste-
riorly. This extent seems to be increased by the squamosal (Tabs. IV and V, 27),
which articulates with the lower border of the produced part of the malar, and
expands to be articulated with the outer part of the lower half of the tympanic
(28), the upper angle rising above the terminal articular part of the malar. This
deep and powerful arch of bone, answering to the zygoma in mammals, may have
afforded attachment to large, masseteric muscles operating upon the lower jaw.
Similar muscles may have been extended between the ridges of the upper and
lower jaws. The tympanic is a long bone, compressed from before backward,
almost vertical in position, with a slight forward bend, but firmly wedged between
the mastoid and par-occipital above and between the squamosal and pterygoid below.

The back part of the tympanic is convex transversely at its inner half, concave
at its outer half, where the margin is slightly produced to join the upper part
of the squamosal; the inner part of the tympanic is more extended where it is
overlapped or abutted on by the pterygoid (Tab. VI, fig. 2, 24). Below this
expansion the tympanic becomes contracted and thickened, forming a kind of
neck to the terminal condyle.

In the vertical position and length of the tympanic, Scelidosaurus resembles
the Lacertia; in its fixity and extent of its connexions, it resembles the Cro-
codilia.

The lower jaw includes in each ramus an articular (29), a surangular (30), a
coronoid (30’), an angular (31), a splenial (32) and a dentary (33) piece.

The articular (Tab. VI, fig. 2, 29) is situated in the inner side of the sur-
angular, and is thickened and projects inward to form the cavity for the major
part of the tympanic condyle, the outer border of which rests on the surangular.
This element (30) convex externally, presents a longitudinal ridge near its
upper part, which rises to join the posterior angle of the dentary element in
forming a low coronoid process. ‘The angular (31) does not extend beyond the
surangular, but makes with it the angle of the lower jaw ; it grows in vertical
extent as it advances, is convex externally, unites with the dentary, and sends
forward from its lower part a pointed process between the dentary and splenial
elements. The splenial (32) makes a small appearance on the outer side of the
ramus, between the angular and dentary, but is chiefly visible as a broad, smooth

12 FOSSIL REPTILIA OF THE

plate (Tab. VI, fig. 2, 32), applied to the inner side of the dentary. The dentary
(33) is a very powerful bone, with the outer surface divided into an upper and
lower facet by a longitudinal ridge paralleling that of the upper jaw. The ridge
(Tabs. IV and V, 33), commencing near the base of the coronoid process, descends,
describing a slight curve to the middle of the outer surface of the dentary.
Below the ridge the bone is convex, above it is concave; the lower facet has
the kind and degree of roughness observable on the exposed surface of most of
the cranial bones; the upper facet has a smoother surface, corresponding in that
respect with the surface below the ridge of the maxillary.

The foregoing character of the lower jaw has, hitherto, been observed only in
a fossil one, which has been referred to the Dinosaurian order; by Mantell,*
originally to Igwanodon, and afterwards, when it had been shown to be more
probably part of the Hyleosaurus,{ to a genus which he called Regnosaurus.{ In
this portion of the ramus of the mandible (No. 422, Reptilian Fossils, British
Museum), the outer surface of the dentary is divided into an upper and lower
facet by a longitudinal ridge, which, commencing near the upper margin, probably
at the base of a coronoid rising, descends as it advances to midway between the
upper and lower border. It is, however, more obtuse than in Scelidosaurus, but the
upper facet presents a like smoothness and vertical concavity.§ In size the speci-
mens closely correspond, and also in the close arrangement of the series of teeth.
But these were relatively smaller and more numerous in the Wealden fossil; for
whereas in Hyleosaurus ten teeth, or their sockets, occupy an extent of 1 inch 8
lines of the alveolar border, the same extent includes only seven and a half teeth or
sockets in Scelidosaurus. In this genus, moreover, the ramus of the mandible
presents a curve convex downwards, to about the same degree as the opposite
curve is presented by the corresponding part of the jaw of Hylcosaurus, in which
this peculiar bend is noticed by me in a former monograph.| In the mandible
of Scelidosaurus a ridge, corresponding, perhaps, to the lower ridge in Hyleosaurus
is situated further back and higher up upon the surangular; and the facet,
concave vertically between the lower ridge and the beginning of the upper
ridge, is peculiar to the mandibular fragment referred to the Hyleosaurus. Thus,
with corresponding Dinosaurian character, imparting robust strength to the man-
dible, there are well-marked generic distinctions in the specimens here compared,
both in the conformation of the jaws and teeth.**

The mandibular rami of Scelidosaurus describe a slight, but graceful, sigmoid

* ©Wonders of Geology,’ 1838, vol. i, p. 393.

+ “Report on British Fossil Reptiles,” ‘Trans. of Brit. Association,’ 184], p. 120.

t ‘Philos. Trans.,’ 1848.

§ See tab. viii, fig. 5, ‘Monograph on Wealden Reptilia’ (1856).

ll byp? 19: q Ib., tab. viii, figs. 1 and 4. ** Thb., tab. vil, figs. 6—9.

LOWER LIAS. 13

curve from the angle forward, horizontally, at first concave, then convex, towards
the median line, where they meet without blending at the part fractured. It is
not probable that the symphysis would be much prolonged beyond this point.
The degree of convergence of the contour lines of the whole skull, both median
and lateral, with the decreasing size of the anterior teeth, makes it more probable
that but a small proportion of the muzzle is wanting in the present specimen
(Tabs. TV and V). The analogy of the Iguanodon might be unsafe ground for
inferring as short a symphysis mandibule in Scelidosaurus, but it would accord
with the other indications of such a proportion of the conjoined ends of the rami.

Dentition. abs. lV and V.

The specimen of Scedidosaurus here described has been buried and petrified
with the mouth shut; there has been no dislocation of the under jaw, and the skull
shows that the teeth of the upper jaw overlapped and concealed those of the lower.
The crowns of both series were a little inclined inward, as shown at the fractured
fore part (Tab. V, fig. 2, 2,4); this, with the similar inclination of the alveolar
plates, produces a feature which reminds one of that of toothless anility, or of the
effect of sucking in the cheeks, in man.

The teeth are small, or of Lacertian proportions to the jaws; they are nume-
rous and close-set, implanted in sockets forming an uninterrupted series along the
alveolar border. The fang is simple, and longer than the crown, presenting a full
ellipse in transverse section, and projecting a little beyond the socket. In the
upper jaw the crown (Tab. V, fig. 3) begins by bulging outward, with a smooth
convexity, subsiding as it gradually expands, and dividing to be continued along the
middle and the margins, with intervening concavities, producing an undulated
surface across the broadest part of the crown. The marginal convexities or ridges
terminate each in a point at the broadest part of the crown; whence, the plate-
shaped tooth having thinned off to an edge, this is divided on each side into five or
six smalier points: these denticulate margins converge straight, at an angle rather
less than a right one, to the apex of the tooth, which is formed by the pointed ter-
mination of the median convexity. ‘The crown is coated by a polished enamel, of
jet blackness in the fossil, smooth under the lens upon the’ convexities, finely
punctate in the hollows of the expanded part of the crown. The whole tooth in
the upper jaw is very slightly bent backward, with as slight an oblique twist,
making the hinder angle overlap the front angle of the crown of the tooth behind.

The inner surface of four of the hind teeth of the right ramus of the jaw
shows a crown with a larger proportion of the serrated part, and with the borders
less equal, the anterior one showing as many as nine points, and the expanded
coronal surface is uniformly and gently convex.

14 FOSSIL REPTILIA OF THE LOWER LIAS.

On the left side, in an extent of the alveolar border of the upper jaw measuring
4 inches, there are nineteen sockets, and only one tooth missing. On the right
side, in an extent of 33 inches, there are sixteen sockets, and three teeth missing.
The fractured part of the Jaw yields evidence of the usual reptilian provision for
successional teeth in reserve alveoli, containing tooth-germs, at the inner side of
the base of the teeth in place (Tab. V, fig. 2,c). The teeth gradually increase in
size from the hindmost to the fifth in advance, continue of about the same size
to the tenth, and then gradually decrease in size to fractured fore part of the jaw.

Were the serrated borders of the terminal half of the crown to be worn down,
the teeth of Scelidosaurus would be like those referred to Hyleosaurus in my
Monograph of 1856.* There is no evidence, however, that any of them have been
so worn down; in this respect they resemble more the teeth of EHchinodon, the
upper teeth in Scelidosaurus differing chiefly in the proportions of length to
breadth of the crown. Whether the anterior teeth had the simple laniariform
character at the fore part of the jaws in Scelidosaurus, as in Echinodon, remains
to be proved. The finely and sharply serrated and pointed teeth of the Scelidosaurus
glided upon each other, the upper on the outerside of the under, like the blade-
shaped crowns of the carnassials of feline mammals; and yet the similarity of the
teeth, in their number and uniformly small size, to those of the modern Iguanas
suggests that they may have been put to like uses. The compressed, serrate
crowns in those herbivorous lizards worked obliquely upon each other, in a similar
scissor-blade way. In Jguanodon the dentition is obviously modified more
decidedly for mastication of vegetable substances. In Scelidosaurus it is adapted
for division of such substances, but it would be equally effective in piercing and
cutting or tearing through animal textures.

If this Dinosaur occasionally went to sea in quest of food, it may be expected
to present in the fore part of the jaws, wanting in the present specimen, laniariform
teeth, as in Echinodon, for the prehension and retention of living prey. Should
these prove to be absent, and the dental series to begin as it ends, it will in-
cline the balance of probability to the phytophagous nature of the Liassic
Scelidosaurus.

* © Monograph on Wealden Reptilia,’ p. 21, tab. viii, figs. 6—9.

MONOGRAPH

ON

THE FOSSIL REPTILIA

OF THE

KIMMERIDGE CLAY.

PLIOSAURIS GRANDIS.

PLESIOSAURUS GRANDIS, Owen. ‘Report on British Fossil Reptiles,’ 8vo. 1839, p. 83.
PLIOSAURUS — Owen. Ibid., 1840, p. 54.

Tooth. Tab. VII.

Although abundant evidence of the huge dimensions of the present species of
short-necked Sauropterygian has reached me since its first indication from the
fragmentary evidence described in my ‘ Reports’ of 1839 and 1840, no specimen
has more strongly impressed me with the bulk and power of the old tyrant of the
upper Oolitic seas, or, indeed, had exemplified its size on such a scale, as the portion
of tooth from Kimmeridge Clay, near Oxford, figured in Tab. VII. This unique
specimen forms part of the Paleontological collection of the Hon. Robert Marsham,
to whom I am indebted for the present opportunity of describing it.

The circumference of the base of the crown measures 7 inches 6 lines, equalling
that of a large-sized tooth of a Cachalot (Physeter macrocephalus). Of the
enamelled crown 3 inches are preserved, and about as much of the cement-covered
base, the largest diameter of which is 2 inches 6 lines; that of the fractured end
of the crown is 1 inch 3 lines. The length of the entire tooth may be estimated
at between 9 and 10 inches.

The fractured part of the base exposes a pulp-cavity (figs. 3,5) of about
2 inches in diameter, with a hard dentinal wall of from 4 to 6 lines in thickness;
the tooth would seem, therefore, to be one that had been but recently protruded.
The fractured part of the crown exposes a solid and compact mass of dentine.
The generic characters of the tooth stand boldly out, and the crown is subtrihedral,
with the two inner or concave sides continued into each other by an uninterrupted
curve, and the angles between these facets and the outer or convex side of the
tooth being blunted, or rounded off. ‘The terms concave and convex refer to the
longitudinal direction; all the sides are convex transversely, the outer one being
the least so. This facet (fig. 1) is further distinguished by the finely wrinkled
and unridged surface of the enamel. ‘The wrinkling is produced by short, obtuse,
wavy risings, frequently joining, or reticulate, and rather affecting the longitudinal
course. The same character is presented by the enamel covering the contiguous
parts of the other sides of the tooth, and extends furthest in that represented in

16 FOSSIL REPTILIA OF THE KIMMERIDGE CLAY.

fig. 2, and between the more distant longitudinal ridges on the side represented
in fig.3. There are no longitudinal ridges on the convex side (fig. 1). The enamel
here, which is a mere film at the base of the crown, slightly increases in thickness
towards the apex; its adhesion to the dentine is promoted by numerous fine,
wavy, longitudinal, nearly equidistant, linear risings on the surface of the dentine.

On the side of the tooth fig. 2 the wavy risings of the enamel become larger,
more distinct from each other, and more markedly longitudinal, as they recede
from the angle dividing it from the convex side. At about an inch distance there
is a definite, longitudinal ridge, of an inch in length, followed by other ridges that
quickly increase in length as they approach the concave side of the tooth, having
pretty regular intervals of about 2 lines. Between these long and well-marked
enamel ridges there are other shorter ones proceeding from the base of the enamel,
of varying lengths.

On the side of the tooth fig. 3, which transversely is more regularly convex
than the side fig. 2, the strong, longitudinal, enamel ridges begin near the angle
dividing it from the smoother convex side, at first with interval of about 3
lines, the intervening enamel being wrinkled, then with intervals of 1 or 14 line,
the more numerous longitudinal ridges continuing along the inner or longitudinally
concave, but transversely very convex, part of the crown of the tooth. Of these
more numerous and closely set ridges, probably the alternate ones only would be
extended to near the apex of the tooth, a few of the others being shown to
terminate at or near the fracture. The longitudinal ridges are strongly and
definitely raised from the general surface of the enamel, and preserve their
thickness to near their termination.

The outer longitudinal contour of the tooth (¢, fig. 2) describes a simple and
slight convexity; the inner one is wavy, passing from the slight concavity at the
crown (4) to a corresponding convexity at the junction of the crown and base,
and then again becoming very slightly concave. The transverse diameter of the
crown is rather less across the convex side (fig. 1) than in the direction at right
angles to this, as from a to 2, fig. 2.

An entire crown of the tooth of a Phosaurus, of the size more commonly met
with, is described and figured in my ‘ Odontography ’ (p. 282, pl. 68, fig. 5).

In the lower jaw of the Pliosaurus from Kimmeridge Clay at Market Raisin,
preserved in the Geological Museum at Oxford, there is evidence of thirty-eight
teeth in each ramus, which were probably opposed to as many in the upper jaw.

I estimate the lower jaw of the Pliosaurus, to which the tooth figured in Tab.
VII belonged, at about 8 feet in length.

J. C. Mansel, Esq., of Langthorne, Blandford, Dorsetshire, has favoured me
with a photograph of the lower jaw (7 feet in length) of a Pliosaurus in his
museum. I hope to include a description and figure of that specimen in a future
monograph.

TAB. I.

Scelidosaurus Harrisonii.

Shaft of femur, half nat. size.

Fig.
1. Front view.

2. Back view.

3. Inner side view.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.

Mus. Norris.

Jos. Dimkel del et Irth vA

TAB: T1.
Scelidosaurus Harrisonit.

Bones forming the knee-joint, one third nat. size.

Fig.
1. Inside view.

. Outside view.

to

3. Back view.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.

Mus. Harrison.

Ungual phalanx, or claw-bone, nat. size.
4. Side view.
5. Articular surface.

6. Upper view.

From the same formation and locality. Mus. Norris.

W.West,imp.

Jos. Dinkel del et lth

's

rally”

TAB. III.
Scehidosaurus Harrisonii.
Bones of a very young individual, nat. size.

Fig. ‘

1. Side view of centrum of dorsal vertebra.
2. Upper view of the same

3. End view of the same.

4. Under view of the same.

5. Front view of a crushed femur.

6. Back view of the same.

7. Tibia.

8, 9. Portion of fibula.

10, 11. Metatarsal bone.

12, 13, 14. Proximal phalanx.

15. Tarsal bone.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.

Mus. Harrison.

as

W.West imp

F Robinson del. et lith

* he
A os ‘7
J i M
i
i - z
ae ie i
a
i a
- a
=4s
a
’
»
,
r we
. i _
re

TAB. IV.
Scelidosaurus Harrisoni.
Side view of the skull, nat. size.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.
British Museum.

+ eG

Ib ae
SEE
u ;

7

Day

BRO ee:
¢

aaa

=

x
4
a
ire
ae

Jos. Dinkel del. et ith. W. West, imp

S Cle UDO Se UEC OSs

TAB. V.

Scelidosaurus Harrison.
Fic.
1. Side view of the skull, nat. size.
2. Fractured fore end of the same, nat. size.

3. Outer side of an upper tooth, magnified.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.
British Museum.

eso
3g AON
baal

W West, imp
Jos. Dinkel del etiifh

‘ a)
a
<
=
rail ‘
re f
.
7 i
“
f
? fi
i
ae
,

TAB. VI.

Scelidosaurus Harrisonu.

Fig,

1. Upper view of the skull, nat. size.

2. Inner view of right ramus of lower jaw, nat. size.

From the upper part of the Lower Lias, Charmouth, Dorsetshire.
British Museum.

ca is

Jos. Dinkel del et lith

‘W.West,imp

TAB. Vil
Phiosawrus grandis.

Portion of tooth, nat. size.

Fie.

1. Convex or unridged side.
2. Front ridged side.

3. Back ridged side.

From the Kimmeridge Clay, near Oxford. Mus. Hon. Robert Marsham.

Nest, imp

V

WY
V

PALDONI ©:

nike! del et ith

Di

Jos I

4!

as 3
res
= *

o

if

Ps

eae x,
Wee ie

PALHONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVIT.

LONDON :

[AT DOTAORIAL

q

-

{
Te

A MONOGRAPH

THE EOCENE MOLLUSCA,

DESCRIPTIONS OF SHELLS

FROM

THE OLDER, TERITLARINS OF FN GAN D:

BY

SEARLES V. WOOD, F.G.S.

PARD I.

BIVALVES.

LONDON :
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1861.

Po

.
.

“BARTHOLOMEW CLOSE.

?

PRE EF AC E.

In the year 1846 Mr. G. B. Sowerby proposed to publish at intervals a series of Plates
illustrative of the Crag and London Clay Fossils, to which Mr. Edwards and myself had
undertaken to supply the descriptions. It was contemplated to issue alternately a
number of each formation in furtherance of this object. ‘The first of these serials was to
be upon the Crag; and at the meeting of the British Association, held in September, 1846,
at Southampton, a specimen plate of the Crag Fossils was exhibited. In January,
1847, Dr. Bowerbank conceived the idea of establishing a society for the purpose of
figuring and describing the fossils of Great Britain, in which he was supported by Dr.
Fitton, the late Dr. Buckland, and other influential Geologists. There was then in existence
a private association, called the London Clay Club, which was composed of a limited
number of Tertiary Geologists, who assembled periodically at each other’s houses for the
study of Eocene Geology, and this was looked upon by the promoters of the contemplated
new society as a good promise of material for its support. The desire of encouraging
such an object rapidly extended, and a large number of gentlemen speedily enrolled
themselves as members of the new society. ‘The Crag Formation had been well examined
by myself, and as it appeared to be one that was best known, seemed to offer to the
friends of the undertaking the most fitting opportunity for commencement; and as |
was particularly desirous of having the Crag fossils figured and described, I conceived
this a more certain mode of extending the knowledge of the contents of that formation
than the one I had previously entered into, and made arrangements accordingly with
Mr. Sowerby for the alteration, and set to work immediately upon the portion allotted
to my labours. My friend, Mr. Edwards, as before stated, intended to publish parts
alternately with myself; but the older Tertiary Formations being much richer in species,
his portion of the work was not so readily prepared as that of the Crag; moreover, what
at that time appeared a feasible mode of proceeding has, by the course of events, become

l

2 PREFACE.

altered, and the known Eocene Mollusca intended to be comprised in his work have since
then been so largely augmented in number, as seriously to impede his progress, and
to compel him to change his original intention. The prospect once entertained by Mr.
Edwards of completing the whole of the Eocene Mollusca thus became so remote that
he proposed to me that, as my monograph on the Crag was finished, I should describe
the Bivalves of the older Tertiaries.

From a knowledge of the amount of labour my friend has before him ere he
reaches the termination of the Univalves, which must occupy him for many years to
come, | was induced to consider whether any assistance that I could render in the
illustration of these fossils would not be of service to the science of Geology. I felt
at first especially reluctant to interfere in any way with a work that has been so
ably conducted, but the great desire expressed by Tertiary Geologists to possess an
illustration of the Mollusca of the Eocene period in this country still unfigured and
undescribed was an inducement to make all other considerations subordinate to that
imperious want, and on that ground alone I have consented to attempt to supply
such a desideratum. Mr. Edwards has in the most liberal manner promised to place
the whole of his Bivalves in my hands, as they may be wanted for examination. His
collection of these fossils is the most perfect I have seen, and as the work was intended
to be done by himself, the type specimens have and will be taken from his cabinet, except
where otherwise particularly expressed ; and the principal localities will be introduced on
his authority. Mr. Wetherell, Dr. Bowerbank, Mr. Prestwich, the Rev. Osmond Fisher,
and all my geological friends, have most kindly permitted me the use of any specimens
in their cabinets, and I have to return them my best thanks for their assistance, with-
out which my work would be very incomplete. Mr. Wetherell’s collection is parti-
cularly rich in the fossils of the London Clay from the north side of London; and Dr.
Bowerbank’s more general collection possesses some choice and unique specimens. ‘I'o
Mr. Prestwich I am further indebted for some of his typical specimens, and more
especially for his assistance in regard to localities. Neither must I omit to mention
that our national museums contain many specimens that have already been used
for the illustration of the Bivalves of these older Tertiaries, or which will materially
contribute to that object; and I beg to express my obligations to the conservators of
these treasures, who have in the most handsome and friendly manner given me every
possible facility and assistance in the promotion of my undertaking. The utmost desire
of every one connected with Paleontology appears to have been shown to assist in
forwarding the good work undertaken by the Paleontographical Society.

S. V. WOOD.
March, 1861.

BIVALVIA

INTRODUCTION.

‘Tue Brvaxyta constitute the third portion of the still greater division of the animal
kingdom called Mollusca, from the word mod/is, a term that might byhypercritics be considered
objectionable, conveying as it does an erroneous impression, the exterior covering of these
animals being im most mstances particularly hard, more so than the internal skeleton of the
Vertebrata. Bivalves are acephalous, or animals without a head, but they are furnished
with a (generally) large and powerful mass of flexible material, called a foot in consequence
of its being the principal organ of locomotion ; this is of importance to the Palzeontologist,
inasmuch as the opening or sinuated edge of the valves at the margin is modified by the mag-
nitude of this foot. It is supplied with circular fibres for extrusion, and longitudinal fibres
for retraction. Although some of these animals are capable of changing their places

1 In the second volume of the ‘Crag Mollusca’ the word ‘ Bivalvia” is employed for those animals
that are without a head, and are enclosed within two valves or pieces of calcareous covering, and it is re-
peated here for the same group. This name appears to me to possess the greatest claim on account of its
priority of date, and itis most expressive in its application. An objection has been made to it, that it does
not include the Brachiopoda, which are also enclosed within two valves, but the same want of isolation may
be urged against the rival claims of Acephala, Conchifera, and Lamellibranchiata. The meaning of each
of these names is not restricted to the characters of the animals they are intended to represent, and the
advantages they offer are not, in my opinion, sufficient to entitle either to supersede the earlier name of
Bivalvia. The Committee of the British Association, in their ‘ Rules and Regulations for Nomenclature’
proposed in the year 1842, and recommended that ‘“‘The law of priority should be admitted as the only
effectual and just one,” but that it should not extend to authors anterior to Linnzeus (ed. 12th, 1767).
The adoption by me of the above name is in compliance with those recommendations.

4 EOCKNE MOLLUSCA.

of abode, many remain all their lives in a stationary condition; some are moored by «a
cable or byssus, secreted for that purpose, by the foot; others are located in an excavation
which is formed when young, and gradually enlarged to supply the increasing wants of
the growing animal. In regard to magnitude, they present a large amount of varia-
tion ; the adult shell of Arycinella ovalis is less than aline in its greatest diameter, while a
specimen of Zridacna gigas in the museum at the India House has a longitudinal diameter
of four feet, giving a difference of more than five hundred im linear dimensions; and the
weight of a united pair of valves of Ke//ia pumila is a fraction of a grain, while Tridacna
is said, with its animal, to exceed six hundred pounds, and these extremes, though
not quite equal to those of the Vertebrata, do not fall very far short of them.

Bivaives in the early period of the world’s existence constituted a much larger pro-
portion of the Mollusca than the Univalves (if that designation be confined to the Gas-
teropoda), although much inferior in number to the Brachiopods. In these proportions,
however, very considerable alterations take place as we approach the present time, in
which the Bivalves are in the minority compared with the Univalves, but largely in excess
of the Brachiopods, the Univalves appearing to have taken the place of the 'Tetrabranchiate
Cephalopods, which were extensively developed during the earlier and middle periods, but
have now, with the exception of one genus, disappeared. The Brachiopods materially
diminish while the Bivalves as steadily increase up to the Tertiary periods ; and although col-
lectively the Bivalve species that have lived, but are no longer in existence, exceed in
number those of the present day, yet at no single period will they bear a comparison with
existing species until we approach the older Tertiaries, their proportions during that
period being not very different to what they are at the present day, if we take into con-
sideration the comparatively limited areas that have been examined in search of fossils.

Bivalves succeed the Univalves in a natural arrangement, the latter being more highly
organized, having an imperfect head with eyes more or less developed ;' the former
have, however, a mouth and digestive apparatus deeply inclosed within the mantle
and its calcareous covering. According to Drs. Carpenter and Bowerbank, the shell
is formed by the secreting action of the epithehal cells covering the mantle of the
animal, andit is enlarged solely by the increase to the margin of the shell, that is, by a
rib or band of shelly matter being added to the external edge of the previously formed
shell. ‘The mantle or cloak which envelops the viscera, though not the most vital organ, is
the most important one to the Paleeontologist, as by this the shell is formed, and on this
the shell is moulded, and the species is determined by what this mantle has deposited.
‘This calcareous covering is exceedingly variable in its composition and solidity ; in some
species the animal appears to possess the power of secreting a large amount of mineral
matter, in others the shell is particularly thin and semi-transparent; in some it is of

1 Species in the Genus Pecfen, as also some in the Genera Avca and Pectunculus, have the margin of
the mantle studded with spots, ‘‘ocelli,’ and these are said to be rudimentary eyes, but they are very

imperfect organs of vision.

BIVALVIA. 5

enormous thickness, highly calcareous, and with only a smail cavity for its inhabitant,
while in others the shell is nearly corneous, and in some the soft parts, as they are
called, constitute almost the entire animal, the mantle having but a very thin coating of
calcareous matter.

Marine shells, as a general rule, are thicker than those which inhabit fresh water, but
in both the variation is occasionally excessive. Ostrea and Pholadomya may be cited
as examples of the extremes of thickness and tenuity in the case of marine Bivalves ;
Unio and Cyclas in those of fresh water. In all these cases, solidity or tenuity of sub-
stance does not appear to have been regulated in the animal solely by the want of a
protective covering as a preservative to its specific existence.

Fresh water Bivalves, like the Terrestrial air-breathing Univalves, do not exhibit the
great specific variation that we see in marine animals of the same class. We might
naturally expect this to be so in regard to shells inhabiting fresh water, when so small
a space is occupied by these animals in comparison with that on which their marine cou-
geners live, but why the land Pulmonata should in specific enumeration be inferior to
other Mollusca is not by any means satisfactorily explained; the bands round the
coast lines which contain nearly the whole of marine Molluscan life being far more
limited in their dimensions than the feeding-ground occupied by the Pulmonata, which
may be taken as the chief part of the land area generally.

The headless animals which compose this group, or the division of it called the
Dimyaria, are nourished and sustained by two siphonal tubes, formed by a prolongation
of the mantle, the one inhalent, and the other exhalent; the former being that through
which the water containing the particles of nutrition is conveyed to the mouth, and for
aérating the branchis, and the latter that which carries off the water after this duty has
been performed. The animals which are furnished with these prolongations are necessarily
supplied with muscles for their extension, as also for their retraction ; and as a considerable
space is required for the play of these tubes, an impression is generally formed by the
retractor muscles upon the interior of that part of the valve, indicating the length or
extent to which they are or have been capable of protrusion, and the depth of the sinus
in general corresponds with the presumed extent of the siphons.

Bivalves are all aquatic, and breathe entirely by means of gills or branchiz, and these
consist usually of four riband-shaped lamella, two of them attached to each lobe of the
mantle; water, therefore, is in their case necessary to sustain life ; a few species, however,
appear to be able to retain a sufficient quantity of moisture to enable them to live for a
considerable time out of water. Shells often acquire an increase of material where there
is a superfluity of lime within their reach, and become too ponderous for any apparent
requirements of the animal.

Most shells in the living state are covered with an outer pellicle or coating, called
the epidermis, a material more animalized, that is to say, there is less of lime in its
composition, and therefore, under ordinary circumstances, less capable of preservation

6 KOCENE MOLLUSCA.

in the fossil state. ‘This is also exceedingly variable, being thick and Opaque in some
species, while in others it is thin and transparent, and in many glossy and _ polished
shells itis entirely absent. ‘The epidermis is said to be a protection to the shell against the
chemical action of acids held in solution by the water; but many fresh- and salt-water
species, although covered witha thick and woolly epidermis, suffer materially by the erosion
of the shell, while those that are less protected by this covering appear to escape altogether.
It is at the umbones, or that part of the shell which is most remote from the more vital
portions of the animal, and in those species which appear to contain a less quantity of
animal matter, that the ravages are committed. In some glossy and polished shells,
such as in the Venus tribe, there is a total absence of epidermis, and these do not suffer
from erosion.

The two valves are held together by an elastic ligature: this has been called
ligament when it is situated on the external part of the shell, and cartilage when it
is internal; but as this fastening is sometimes composed of a portion of each, we are on
those occasions unable to characterise it by either of those terms a/oze, and I think it ought
to have a peculiar name for its joint and general service; 1 propose, therefore, to call it
connexus (the connector). When this ligature is external, it acts over a support or fulcrum,
and by its elasticity contracts in order to open the valves; it is then digamentous. When it
is placed within the outer margin of the shell, it is carti/aginous, opening the valves by its
expansion; and when it partakes the double character of ligament and cartilage, it is
amphidesmous or bipartite. This elastic material is then extended both outwardly and
inwardly, and although in this case the ligament and cartilage are united, there is always
a slight elevation or partition between them, and this forms the fulerum over which the
ligament acts. ‘The two picces of the Bivalve are thus naturally kept open by the
elasticity of the ligamentous portion in its contraction, and by the cartilaginous in its
expansion, and when the two valves are closed in the living animal it is by the contrac-
tion of the adductor muscles. In the fossil state Bivalves are of course often found in
their natural position, that is, with the margin of the valves separated in the way the
dying animal has left them on the relaxation or rather paralysis of the muscles,
but the two valves are as often quite closed; this, of course, must be from external
pressure overcoming the action of the connexus.

Although the two valves are kept together and held in position by the connexus, they
are often further secured by prominent processes, called teeth, which prevent a lateral
motion ; these are said to be strong and prominent where there is weakness in the connexus,
and, as a general rule, amongst the Dimyaria the observation is more applicable to those
shells where it is on the outside (7. e. ligamentous), while in Mya, Anatina, &c., which have
the connexus internal (7. ¢. cartilaginous), there are no prominences or teeth. ‘This rule,
however, like most others, is not without exceptions ; Wwcula, Leda, Mactra, &c., have the
dorsal margins furnished with numerous and prominent interlocking teeth ; perhaps, as a
general rule, the more locomotive species have the strongest hinge. ‘The dental apparatus, in

BIVALVIA. 7

conjunction with the connerus, constitutes the hinge on which the valves open and close.
The Brachiopoda, which have also two valves, differ from Bivalvia in wanting the
connecting ligament, and the opening as well as the closing of the valves is in that class
effected by muscles; they differ also in having one valve perforated, through which the
byssus passes, and as this opening is enlarged during the growth of the animal, the infant
state of that perforated valve is entirely destroyed, but the infant state of the Bivalvia is
visible in both valves at all ages in the umbonal region of the adult shell.

The adductor muscles of the Dimyaria are generally of the same magnitude, or at least
nearly so; where there is a difference, it is in those animals whose shells are greatly
inequilateral, the larger portion then requiring somewhat greater power in closing the
valves. The pedal and siphonal regions are easily known in most species, even in the
equilateral or orbicular shells, by the position of the connexus when it is only on one side
of the umbo, as in that case it is always more or less on the siphonal side, even in those
shells where it is wholly internal or cartilaginous; but in genera, such as Pectunculus,
Limopsis, and the equilateral Arce, which have the connexus spread over a large area
equally on each side of the umbo, it is by no means so readily determined. The siphonal region
may, however, be generally recognised by the impression of the anal adductor bemg somewhat
higher up, permitting the openings for the incoming and outgoing currents to pass beneath
it, and the oral adductor is slightly prolonged by the union of the pedal muscle, which
in these animals is required to move their large and expansible foot.

The Bivalve shell has always been described as having an anterior and a posterior
extremity, and it would be desirable still to retain that general description, if it were not
for the diversity of opinion there always has been, and which still exists, amongst
conchologists, as to which should be considered the anterior and which the
posterior portion of the animal. It is at times difficult to determine, in descriptions,
which is intended by the author as the anterior, and which as the posterior, for these
terms are sometimes employed conversely. I believe the animal in its shell will
sufficiently denote the anterior and posterior of itself by the position of the mouth
and anus, as in all animals where these are separated the first is considered anterior and
the last posterior; but in the Bivalvia it is said by those who advocate the reverse of
this, that the indrawing tube of the animal by which nutriment is conveyed to the
palpi, and thence to the stomach, is on that part which by some is called posterior, but
which ought, on that account (they say), to be called the anterior, and also that this portion,
in all boring Bivalves, for example, is always the uppermost or anterior in their retreat.

I have therefore thought it expedient in this monograph to substitute for these terms
an alteration by which, it is hoped, the confusion may be avoided. That which I have called
the pedal region ought perhaps, more strictly speaking, to be considered as the buccal
region, and the opposite one the anal, but the Palontologist is more especially con-
cerned with the shell and its interior, which bears the impress of the muscles only, and
not of the viscera, or at least very rarely so. I have thought it better to employ those

8 KOCENE MOLLUSCA.

terms with which the conchologist, rather than the malacologist, is most familiar; I
therefore introduce a figure with a formula of explanation, making as little alteration

in existing terms as possible.

; Ai iN A ot eo Br. | ST 3 lt a A
} Ee 14 [ oa } length Sarit

wv. Ht
u. Umbo. c. p. Cartilage pit
u. x. Umbonal region. l, f. Ligamental fulerum f comnexns
p. r. Pedal region. p.m. Pedal muscle.
s. 7. Siphonal region. o. a.m. Oral adductor muscle.
l. 7. Lunule region. a. a.m. Anal adductor muscle.
c. *. Corslet region. p. 7%. Palleal impression.
d. m. Dorsal margin. s. s. Siphonal sinus.

c. t. Cardinal teeth.
1. ¢. Lateral teeth.
d.v. Depth of valve.

v. m. Ventral margin.
p.l.m. Pedilateral margin.
s. 7. m. Siphonilateral margin.

\ considerable difficulty exists in the mode of estimating the dimensions of a
Bivalve, from the want of accordance amongst conchologists in denominating the
different parts of the shell, the length being sometimes considered to extend from the
umbo to the ventral margin, the breadth from the pedilateral to the siphonilateral
margin, and the most tumid portion of the closed valves as forming its height. At other
times it is the reverse of this. In my monographs I have adopted the latter method,
conceiving it to be the more natural one. ‘The base on which the animal stands is the
ventral margin, and on which it is moved by the foot in all those which are locomotive ;
therefore the height should be from that base to the vertex or umbo, and the length
consequently should be taken in an opposite direction, while the tumidity of the valves
may be considered the depth, and the substance of the shell its thickness.

In the Dimyaria, which are generally transverse shells, and have a greater diameter
from the pedal to the siphonal region, there is no difficulty in thus considering these
various dimensions; but with the orbicular shells, or with those whose elongation is from

: BIVALVIA. i)

the umbo to the ventral margin, such as Lima, Vulsella, Oslrea, &e., we are much perplexed
with the application of these terms, as we meet sometimes with a shell whose height will
exceed the length two or even threefold, and the longest diameter in that case is in
ordinary parlance called the length, and this is often so employed by those who estimate
generally the length of the Bivalve from the pedilateral to the siphonilateral margin. The
same terms ought in our descriptions to be employed for such shells as O. Virginica, as is
done to those like So/en, &c., where the longest diameter is in an opposite direction.

The older Tertiary species of England are, I believe, with a very few doubtful exceptions,
all extinct, but they have a generic representation among existing forms. This, of course,
must depend upon what is to be accepted as sufficient for a generic distinction.

A genus is said to consist of a group of species related by community of structure and
parts comprehending all essential characters. In Bivalves the xwmber and position of the
hinge-teeth, as also the position of the connexus, whether external or internal, are considered
by some authors sufficient, when separately estimated, to characterise a genus; while
others will regard some of these distinctions as unimportant, or, at least, of only specific
value." The definition of a species is equally unsatisfactory ; it has been given in the
following formula :—‘ All specimens or individuals which are so much alike that we may
reasonably believe them to have descended from a common stock (parent or parents), con-
stitute a species.” It is, however, found in the practical examination of individuals that
the lme between these groups is generally so ill-defined that we are led to doubt whether
there is in nature any such distinction as we find it convenient to make in order to suit
our own purposes. Great authorities say that ‘‘no general rule can be laid down for
determining the distinction of species, as there is no particular class of characters which
can serve as a criterion. In each case we must be guided by analogy and probability.”
It thus appears that our determination is mainly dependent upon individual opinion, and
we have nothing whereby it can be decided that the conclusion of any author is the correct
or real one. Those only who have laboured hard to fix the limit of a species out of a
multitude of specimens, of similar or proximate forms, can tell the uncertainty attending the
determination of such a distinction, and the unsatisfactory conclusion at which the
naturalist often arrives ; and when the varying opinions of preceding authors are weighed

1 In order to show the difficulties which exist in characterising such a section, we may take the
Genus Lucina as anexample. This Genus, as admitted by several modern authors, contains shells possessing
differences which, in other portions of Bivalvia, are considered as being in themselves separately entitled to
generic distinction. Thus, Lucina comprises: Ist, shells without hinge-teeth ; 2dly, shells with cardinal
teeth only; 3dly, shells with one lateral tooth; 4thly, shells with two lateral teeth. This genus also
contains species in which the connexus is both outward and inward: Ist, those in which it is wholly
external, with a thick and solid shell, such as L. columbella ; 2dly, those in which it is amphidesmous, with
a thin and almost diaphanous shell, such as ZL. flewuosa ; Sdly, those in which it is situated internally,
opening the shell by expansion, as in L. lactea ; besides these differences, some species are perfectly plain
and free from sculpture, while others are beautifully ornamented, and the animal also partakes of the
varying characters of the shell. ;

2

10 KOCENE MOLLUSCA.

and critically examined by their successors, we are so much nearer a successful decision
only by a more general concurrence of opinion in favour of one set of determinations than
of the other.

The duty of the Palzeontographer is to give good figures and copious descriptions, in
the hope to secure similar determinations by the largest number of those naturalists
who have well studied the intricacies of the subject, and thus to afford a test by which
those who succeed may gauge and determine the value of his conclusions.

The difficulty which, in the course of my study of the Mollusca, I have frequently
encountered in assigning the true specific value to forms which, in a series of individuals,
exhibited such an approximation to other forms called specifically distinct, long since raised
in mea doubt of the reality of specific distinctions as a fact in nature, which reflection upon
the general nature of organisms matured into a conviction that all organisms originated by a
natural process of slight variation accumulating in a given direction out of other and pre-
existing organisms. I was therefore, fully prepared for the enunciation of the theory of
Mr. Darwin, that all forms have originated by selection, and I readily concede that process
to be one of the most powerful, if indeed it be not the sole cause of all the varied forms of
being that have peopled the earth. Nevertheless, specific distinctions, empirical or artificial
though they may be, must always be to a certain extent recognised as essential to the
proper working out of our knowledge of Palzontology, and particularly to a correct appre-
hension of the true ages of geological formations, and of the reduction of those widely
severed in area to a common horizon. ‘The general recognition, however, of such an
origin for organisms, if indeed that ever be conceded by reluctant Paleeontologists, will,
in addition to the importance of the discovery of so great a truth, be no little boon to the
hard-working naturalist, whose labours have been seriously aggravated by a desire for
species making.

It is intended here to describe all the species of British Bivalves belonging to the
Eocene or older 'Tertiaries of England; these, with the Crag and overlying deposits, con-
stitute the Tertiary remains in this country.

The great Eocene Formation in England has been separated into ten distinct series of
deposits, viz., the Bembridge, Osborne, Headon, Barton, Bracklesham and Bagshot series,
the London Clay, the basement bed of the London Clay, the Reading and Woolwich series,
and the Thanet Sands. ‘These divisions are based principally upon geological and
lithological evidence. I have not been able to characterise these various distinctions by
their organic contents, but have merely introduced the localities of the different species so
far as they are known to me.

The Marine Fauna of the Eocene Deposits appear to have their connexion with the
existing types of the eastern seas, where several of the Eocene genera are only now to be
found ; this is rather more strongly displayed by the Cephalopoda and Gasteropoda than
by the Bivalves, although in this latter division we have not less than seven genera now
confined to seas lying south-east of this country, viz., Vulsella, Cucullea, Cardilia,

BIVALVIA. 1]

Fimbria, Thetis, Cultellus, and Limopsis.’ In the higher group of Mollusca as many as twelve
genera may be enumerated, viz., Mautilus, Péerocera, Seraphs, Harpa, Metula,’
Borsonia, Rotella, Pyramidella, Niso, Nematura, Phorus, and Parmaphorus, also now
confined to the south-eastern seas, and these genera appear to represent a relationship to
the Marine Fauna of the Eocene period more especially than any others I can instance.

The land and fresh-water species have, I think, on the contrary, retired in an opposite
direction, as their connexion appears to be more especially with the existing types of the
American Fauna. Mr. Edwards has described fifty-seven species of Pulmonata from our
Eocene Deposits, of which only ten, he considers to be identical with fossil species of the
European Continent, and this I imagine arises from a difference in the direction of the
rivers which flowed into the Paris Basin Sea, and which were quite distinct from the one
that is presumed to have been emptied into the Hampshire Beds.

The Bivalves now to be described comprise species of fresh-water animals as_ well
as those from estuarine and marine deposits of the great Hocene Formation in this country.
The estuarine animals were, no doubt, shallow-water species, and the principal part of the
marine from the littoral or sub-littoral zones ; the deep-water portion of the period being,
in all probability, the great Nummulitic deposit. We are able, in some degree, to surmise
the probable depth of the sea of a marine deposit, from the collective indications of the
various genera it contains, whose habits are presumed to be similar to those of existing
analogues, but even in these suppositions extreme caution ought to be observed. The
dredgings of Mr. M‘Andrew and others, among existing Molluscs present us with anomalies,
which show that in some genera, as, for example, in Chiflon, Trochus, &c., which generally
inhabit the littoral zone, species have presented marked exceptions to this rule, as they
have been found alive in deep water only. A conclusion, therefore, drawn from a single
extinct species can not be entirely depended upon, inasmuch as the habits of the
animal might have resembled those of the exceptional cases in existing genera.

1 This genus has one species living in the Red Sea, one at Singapore, one off the Cape of Good Hope,
and one (perhaps two) have been found in the North Seas. These last are probably the prolonged ex-
istence of the Crag species; otherwise the generic relationship is with the south and east.

2 Mr. P. Carpenter has, in his valuable ‘Report on the Mollusca of the West Coast of North America,’
introduced four species, but the generic name is accompanied by a mark of doubt.

ANOMIA. TZinn., 17672

Generic Character. Shell inequivalved, irregular and variable, subequilateral, ovate
or suborbicular, and slightly pearly within; upper or left valve convex, smooth, lamellar,
striated, costated or muricated; lower valve flattened, sometimes very slender, with
a large foramen, through which passes a calcareous appendage, or calcified byssus, for the
attachment of the animal. One muscular impression in the lower or fixed valve, and
four in the upper. Connexus cartilaginous ; hinge edentulous.

Animal unsymmetrical, with the edges of the mantle disconnected, except at a small
spot near the hinge ; its margin double, slightly fringed, without ocelli or rudimentary eyes ;
foot very small, cylindrical, expanded at the end, and grooved ; byssus large, passing through
a nearly complete foramen in the right mantle lobe, and attached by a powerful muscle to
the centre of the left valve. One adductor muscle ; palleal line continuous. Sexes distinct.

The impressions of four muscles are left upon the interior of the upper or left valve ;
one of the four is that of the adductor, and is the only one impressed upon both valves.
The largest of these muscle-marks is the attachment of the byssal plug; probably the two
centre marks belong to that organ, and the small one in front of the cartilage-pit is caused
by the retractor of the foot. The animal cements itself to the rock by the byssus, which
contains so much calcareous matter that it becomes as hard as the shell itself, and this
plug is found in the fossil state in the upper, though I have not yet seen it from the lower,
Tertiaries.

The right or adherent valve is very thin, oftentimes almost obsolete, and in some
species it is much less in size than the upper, so that the mantle extends considerably
beyond the edge of the shell, showing the lower valve to be almost useless ; the perforation
of this valve in some species is very large, with an unconnected margin ; indeed, this is the
more common character. The cartilaginous connexus is placed on a projecting piece of
this valve, behind which the shell is thickened with a sort of double ridge running into
the body of the valve ; this is often the only portion preserved in the fossil state, and I
now find that to have been the condition of the little Crag fossil, which I imagined to
have been the internal shell of a Gasteropod, and figured in the ‘Crag Mollusca,’
doubtingly, under the name of Aplysia.

The umbo of the upper valve in some specimens of this genus is removed to a con-
siderable distance from the margin of the shell, and in its exterior makes, in appearance,
an approach to the limpets. The large and extended muscle-marks of the interior

| For generic synonyma see ‘Crag Mollusca,’ Part ‘“ Bivalves.”

BIVALVIA. 13

also resemble the impression of the adductor in some of the capuloid shells, more especially
those of the Genus Azpponye, in which the animal constructs a shelly base resembling a
second valve, and the adductor in that Gasteropod has the twofold purpose of the Bivalve
muscle, adhering to the shelly base as well as to the interior of the conical shell, forming
and leaving a similar mark deeply impressed upon the inner surface of each piece, the muscle
extending itself behind the foot, and this otherwise large “ belly-foot” of the Hipponyz is
contracted to permit it to take hold of the shelly base. ‘These impressions in Anomia
indicate the presence of powerful muscles, although the animals possess little more than
the rudiments of a foot. The genus is far removed from those animals which have only
one piece of shell (the Univalve), but they are perhaps nearer than any other Bivalves, and
they are, I think, appropriately placed here at the head of the list.

In the recent state, this genus has an extensive geographical range, species belonging
to it are found in America, India, Australia, the Mediterranean, and the North Seas.
It is not numerous in species, either as recent or fossil.

1. Anomra tenuristriata, Deshayes. Tab. IX, fig. 1, a—e.

ANOMIA STRIATA. J. Sow. (non striata, Broc., 1814). Min. Conch., t. 425, 1823.
— — Galeotti. Mém. Cour. par l Acad. Brux., t. xii, p. 151, No. 89, 90.
— eEpnippiumM. Defrance. Dict. des Sc. Nat., t. 2, 1823.
— trnurstrtata. Desh. Coq. Foss. des Env. de Par., t. 1, p. 377, pl. 65, figs. 7—11.
— — Sow. In Dixon Geol. of Sussex, p. 117, t. 4, fig. 8; and t. 14,
fig. 17, 1850.
_ ? Grateloup. Cat. des An. du Bas de la Gironde, p. 56, 1838:
— u#vicata? Nyst. Coq. Foss. Belg., p. 311, pl. 26, figs. 4—6, 1843.
— orRBIcuLATA’ Id. - - 2° ped l2oply25; fie. 6, 2,6.
— wineata. J. Sow. Min. Conch. Syst., index, 1835.
—_— — Morris. Catal. Brit. Foss., p. 161, 1854.
ANOMYA TENUISTRIATA. D’Ord. Prod. Paleeont., p. 395, No. 1148, 1850.
— SUBSTRIATA ? Id. - - p- 396, No. 1150, 1850.
— suBLmvieaTa? Id. - - p. 396, No. 1149, 1850.
OstREA ANOMIALIS. Lam. Hist. des An. sans Vert., t. vi, p. 220, 1822.

Spec. Char. A. testd tenut, suborbiculari, irregulari, valde inequivalvi, valvd superiore
convend, tenuissimé striatd, valvd inferiore plana foramine magno ; umbone submarginali.

Shell thin, irregular, rounded, and finely striated externally ; upper valve much the
larger and convex ; lower valve small, flat, and thin, with a very large opening for the plug ;
umbo near the margin.

Diameter, 2 inches.

Locality. Alum Bay, Barton, Bramshaw, Brockenhurst, Brook, Bracklesham, Bognor,
Clarendon, Stubbington, Whitecliffe Bay (Zdwards), Clewett’s Green, Newnham (Prestwich),
Highgate (Wetherell).

Belg., Env. de Bruxelles, Sables d’Uccle et de Forét (WVysé).
France, Grignon, Montmirail, Senlis (Desh.), Blaye (Grateloup).

14 KOCENE MOLLUSCA.

‘This, like most of the species in this restricted genus, is very variable, assuming a
shape in some degree conformable with the place in which the individual has chosen to fix
its abode; and although the generality of specimens have the upper valve convex, it
occasionally happens that this valve is flat or even slightly concave outwardly ; the form is
sometimes elongately ovate, while at others it is elevated, but when quite free and not
distorted it is nearly orbicular, as may be scen by the specimen figured, which displays its
natural shape. ‘The same habits existed in this animal as in species of the genus at the
present day. One of Mr. Edwards’s specimens adhered to the back of a Pecten, the
markings and rays of which it has assumed with great regularity (fig. 1, ¢).

In the young state of this shell the striae are wholly invisible, and, indeed, in some
of the larger specimens they are only to be detected by a powerful lens; it is so in those
from Clarendon, and this I imagine is the condition of those specimens to which the names of
A. levigata and A. orbiculata have been given. The muscle-marks in the upper valve are
well displayed; the larger one, the muscle of the plug, is situated under the cartilage-pit,
and is more than double the size of the adductor, and corresponds with the large foramen
of the lower valve; the shape of this mark is modified by the shape of the shell; the upper pedal
impression is close to the corner of the cartilage-pit, and I had imagined at one time
that a difference in form existed between the specimens from Clarendon and those from
Barton, but apparently this is not a permanent character, and these markings are all
variable in outline. In the specimens from Grignon the same variableness in these muscle-
marks may be observed; they assume, in a great degree, a shape much in accordance with
the outward form of the shell. Iam unable to detect a difference which might fairly be
considered specific between any of the specimens, from the lowest to the uppermost of
the older Tertiaries through which this Anomia extends. ‘The umbo or beak of the shell
is likewise an unstable character; in some specimens it is immediately on the margin,
while in others it is at a little distance from it, aud Mr. Sowerby says (‘ Min. Conch.’, p. 32)
that the shell, when old, is contracted towards the beak, but this condition is probably
accidental, as it occurs only in some specimens.

Barton specimens seldom exceed an inch in diameter, while those from Brackles-
ham are double that size. I have seen only a few from Clarendon, and those were
small. The shell is generally more or less tinged with a reddish-brown colour, particularly
the Bracklesham specimens, and probably contained a good deal of animal matter. ‘This
species ought strictly to be called 4. anomiahs.

2. ANomrA scaBrRosa, S. Wood. ‘Tab. XI, fig. 5, a—e.

Spec. Char. A. testé minutd, orbiculatd, compressa, tenui ; valvd superiore costulata
vel radiata, et valde imbricata, imbricibus magnis et regularibus ; valvd inferiore planulatd ;
Soramine parvo.

Shell small, orbicular, somewhat compressed, thin; upper valve costated or radiated,
with large and elevated imbrications ; lower valve with a small opening.

BIVALVIA. L5

Diameter, + of an inch.

Locality. Wampstead (Ldwards).

Two or three specimens are all that I have seen. ‘The imbrications upon the upper
valve are large and elevated, presenting a very rough exterior, resembling the surface of
a blacksmith’s file. The lower valve shows the round foramen to be on the left side of the
umbo, from which I presume the exposed surface to be the interior of that valve.

We have thus in these older Tertiaries the prototypes of the striated and imbricated
recent British species, only in excess, the one more roughly imbricated, and the other less
coarsely striated.

OSTRHEA. JZznn., 1685.

Generic Character. Shell attached by the larger or lower valve, generally thick and
strong, lamellated or foliated, variously shaped, irregular, inequivalved, inequilateral ;
upper or free valve flat or slightly concave; under valve convex, sometimes strongly marked
with radiating, lamellated costa ; hinge without teeth ; connexus ligamentous lodged in an
elongated, triangular depression in each valve. Impression of the adductor muscle large,
subcentral, that formed by the mantle entire, generally indistinct and ill-defined.

Animal with the mantle-margin double, or disunited; its edges bordered by short,
tentacular fringes ; foot obsolete. Sexes distinct.

The oyster fixes itself by the outside of the left valve, and as this is done generally upon
a horizontal support, the valves, from that position, are called upper and lower, and although
they are unsymmetrical and inequivalved, they are nevertheless bilateral, and have a right
and left valve like the Dimyaria. Oysters are generally gregarious animals, although some
species appear to be solitary. Ostrea folium, an Oriental species, secretes projecting
processes or fingers, which extend from the back of the lower valve, and by which
it clasps the roots and branches of trees which grow into the water, from which
habit it was called Dendostrea by Swainson. This, of course, is done when the
animal is young, or only so long as the edge of the mantle can be extended to
the extremity of the processes, after which they cannot be prolonged. Some oysters
are peculiarly prone to secrete a large quantity of lime, particularly where that material is
abundant; and a fossil oyster from the banks of the Tagus has been found with its lower
valve two feet in its longest diameter, and of a proportional thickness. ‘The oyster, in
general, is adherent in the younger state, but when it has grown large and heavy it ceases
to increase the attachment, and enlarges the shell, like a free Mollusc. Some species adhere
only by a very small portion of the shell, while others are attached by nearly the whole of
the outer surface of the lower valve ; this character is, however, variable, even amongst
individuals of the same species. The genus inhabits salt water, although the common
edible oyster will live in rivers in England where the water at low tide is nearly fresh.

The age of the oyster is probably various in different species ; O. edulis is said to live

16 EOCENE MOLLUSCA.

about ten years, but to come to perfection in four or five. Fishermen pretend to be
able to tell the age of this Mollusc by the discoloured fimbriations upon the lower valve,
somewhat like the hybernating marks upon the snail.

1. Ostrea apuata, S. Wood. Tab. V, fig. 3, a—c.

Spec. Char. O. testd minimd, ovato-elongatd vel irregulariter cuneatd, apice obliquo ;
valud inferiore radiato-costatd, plus minusve profundd ; valvd superiore planiusculd vel con-
vewiusculd ; marginibus superne granoso-plicatis ; impressione musculari sublunart.

Shell small, ovately oblong, or irregularly wedge-shaped, apex oblique; lower valve
radiately costated, more or less deep; upper valve flat or convex, margin near the hinge
crenately plicated; muscular impression sublunate.

Longest diameter, 1 inch nearly.

Locality. Wempstead, Isle of Wight (Ldwards).

There is something peculiar about this little shell which seems to entitle it to an isolated
position, and I have, in consequence, given it anew name. It is a miniature representation
of O. flabellula, but the coste are fewer and do not appear to be visible in the young
shell. All the specimens I have seen are attached to Certthium plicatum ; this, perhaps
being the most abundant univalve in the deposit, has been selected for that purpose, and
the oyster has sometimes fixed itself in the direction of the height of the univalve, by which
it has become elongated from the umbo to the ventral margin, and has thereby altered
the natural form of the shell. In one or two specimens the coste are obsolete or scarcely
visible, and the margins of the valves near the hinge appear to have interlocked ;
having crenulations in the right valve corresponding with depressions in the left for
their reception. ‘The cylindrical support of the animal has not only reduced the depth or
capacity of the lower valve, but this internal prominence has communicated its form to the
upper valve, making it very convex. It is similar in habit to O. mutadilis, Desh. Coq.
Foss. des Env. de, p. 344, pl. 56, f. 9-10, but that species does not appear ever to
have had its lower valve plicated.

2. OstrEA ALIENA, S. Wood. ‘Tab. VIII, fig. 2.

Spec. Char. O. testd tenui, ovatd vel ovato-rotundatd, valvd inferiore convexiusculd,
eatus rregulariter costulato-radiatd, sub-lobatd.

Shell thin, ovate or ovately rounded ; inferior valve slightly convex, and covered with
radiating ribs or riblets, and slightly lobed.

Diameter, 3 inches.

Locality. Bracklesham (Zdwards).

‘There are a few specimens of Ostrea in Mr. Edwards’s cabinet, which [ cannot
satisfactorily assign to any species known to me, and I have given to them the above
name provisionally.

BIVALVIA. 17

The principal distinction is the thinness of the shell and the smallness of the hinge-
area, with rather small and distant ribs in which characters, as well as in the form of
the muscle-mark, it seems to differ from the young of O. Bellovacina, to which it other-
Wise somewhat approaches. I have not seen the upper valve.

3. Ostrea Betitovacina, Lamarck. 'Vab. II, fig. 1, a, 4, and Tab. VII, fig. 3, a—e.

OstREA BeLLovacina. Burtin. Oryet. de Brux., pl. 10, figs. a—d, 1784.
— — Lam. An. du Mus,, t. viii, p. 159; and t. xiv, pl. 25, fig. 1, a, 4,
1806.
== — J. Sowerby. Min. Conch., t. 388, figs. 1, 2, 1823,
-- = Deshayes. Coq. Foss. des Eny. de Par., p. 356, pl. 48, figs. 1, 2;
pl. 49, figs. 1, 2.
—- = Goldf. Petr. German., t. 11, p. 15, pl. 77, fig. 2.
— — Nyst. Rech. Coq. Foss. de Hoesselt and KI. Sp., p. 16, No. 41,
1836.
— — Nyst. Coq. Foss. Belg., p. 318, pl. 30, fig. 1, a; pl. 31, fig. 1, 0;
pl. 32, fig. 1, @; pl. 33; fig, 1,6); 1843.
EDULINA, Lam. Hist. des An. sans Vert., t. vi, p. 218, 1822.
— _ J. Sowerby. Min. Conch., t. 388, figs. 3, 4, 1823.
— uNnbuLATA? J. Sow. (non Nyst). Min. Conch., t. 238, fig. 2, 1819.

Spec. Char. O. testé ovatd, depressiusculd, valvd inferiore convead, radiatim et rugosé
costatd, et squamoso-foliaced; valvd superiore planatd, obsolete radiatd ; concentrice lamellata;
/mpressione musculart mediocri, ovato-semilunari ; umbonibus subequalibus.

Shell ovate, rather depressed, lower valve convex, with rugose, radiating ribs or ridges,
foliations squamose; upper valve nearly flat, and obsoletely ridged by lamellated lines
of growth; muscular impression of a moderate size, ovately lunate; umbones nearly
equal.

Longest diameter, 4 inches.

Localities. Charlton, var. a, Dulwich, var. B (Ldwards).

France, Hauteville, Beauvais (Zamarck).
Belgium, Kleyn-Spauwen, Hoesselt et Lethen (Vys/).

Oysters occur almost throughout the whole extent of the lower beds of the Eocene
Formation in England, and all the specimens that have been found were for a long time
considered by geologists as varieties of O. Bellovacina, and the geographical range assigned
to this species extends from Clarendon, Pebble Hill, and Newbury, through Reading, to
Northaw and Rochester, including within these outskirts the central portions of Woolwich,
New Cross, &c. On expressing an opinion to my friend, Mr. Prestwich, that there were
two species found in these lower beds, and my wish, if possible, to have them separated,
and their proper localities assigned, and requesting his assistance for that object, I learnt
from him that he had, since the publication of his paper, strongly suspected that the

3

18 KOCENE MOLLUSCA.

numerous shells united under the name of Bellovacina in the lower London Tertiaries
belonged to more than one species. I had hoped to have been able to assign to these their
respective localities, of which not less than twenty are recorded; Mr. Prestwich fears
that, without a re-examination of the ground, this cannot be satisfactorily done.

The costa in the wpper valve of our shell are visible in most of the specimens found at
Woolwich ; these may also be observed in some from Beauvais, although in the generality of
specimens from this latter locality they are obsolete. Tab. VII, fig. 3, 4, has the upper
valve quite free from these radiations, while in Tab. VII, fig. 3, c, another specimen from
the same locality, they are very distinct. Differences quite as great, or even greater, may be
observed in specimens of O. edulis. M. Hebert considers the shell from Kleyn-Spauwen,
figured under this name, to be a different species, and says (Bull. de la Soc. Géol., 1848-9,
p- 469, No. 7) that he has examined only the upper valve, and that this presents sufficient
differences to entitle it to be specifically removed from Bel/lovacina; having seen only
one valve, he refrains from giving it a new name. ‘The shell represented by M. Nyst has
distinct radiations upon the upper valve, but the muscle-mark seems rather more rounded
than in the British fossil, which is reniform and somewhat pointed; the same may be said
of the figure of the muscle-mark given by M. Deshayes from the Paris Basin; in a
specimen I have from Beauvais, the muscle-mark precisely resembles those in the
Woolwich specimens. I believe them to be the same species.

Philippi introduces this name as a fossil from Palermo, but he gives no figure, only a
description, and this so short that it might be adapted to other species. In the Museum
of the Geological Society is a specimen from Gibraltar much resembling our shell, but I
think it is distinct ; it has rather larger radiations, and these are more foliaceous. Sir
Charles Lyell gives the name of Belovacina to an Ostrea found in limestone at the
“ Grove,” about seventeen miles north of Charleston, in South Carolina, ‘ Proc. Geol.
Soc. Lond.,’ February, 1845, p. 567, and I have seen a specimen, in Sir Charles’s cabinet,
from Virginia (without a name), which, in some characters, resembles O. pulchra ; I can
scarcely think it strictly identical either with it or with Bel/ovacina.

4, Ostrea caLiirera, Lamarck. Tab. V, fig. 1, a, 6.

OsTREA CALLIFERA. Lam. Hist. des An. sans Vert., t. vi, p. 218, No. 19, 1822.
— — Desh. Cog. Foss. des Env. de Par., t. 1, p. 399, pl. 50, fig. 1; and
pl. 51, figs. 1, 2, 1824—37.
_ _ Id. An. sans Vert. du Bassin de Par., t. 1, p. 110, 1860.
—_ _ Goldf. Pet. Germ., vol. ii, p. 27, No. 71, pl. 83, fig. 2, d—f, 1833.
= — ? WNyst. Coq. Foss. de Belg., p. 317, pl. 29, fig. 1, a, 1843.
— — Bronn. Lethzea Geogn., t. 39, fig. 14, 1836.
— _ Forbes. Mem. Geol. Surv., 1856, pp. 46—145, pl. 1, figs. 5, 5, a.
— uipropus? Lam. Loe. cit. sup.,t. vili, p. 159, No. 2, 1806 (non hippopus recens).

Spec. Char. 0. testd ovatd, hine prope basim callo crasso subauritd ; valvd majore

BIVALVIA. 19

crassissimd, intus irregulariter excavatd ; extis lamellosd, valvd superiore plané vel concavd ;
apice ad sinistram? arcuato ; ared ligamenti lata.

Shell ovate, with a projecting callosity on the opposite side to the curved umbo ; shell
thick, irregularly excavated ; externally lamellated ; upper valve flat.

Dimensions, 4 inches by 3.

Localities. Hempstead, Isle of Wight (Fordes).

Belgium, Pietrebais, prés de Chapelle St. Laurent (JVys¢).
France, Roquencourt, le pare de Versailles (Desd.)

This species, so far as I know, is in England confined to the upper beds of the older Ter-
tiaries called the Hempstead series, and there it does not appear to be abundant. Its peculiar
character is the callosity on the left or lower valve, caused by the broad adherence of the
animal inclining to one side ; this habit is retained until it is considerably advanced in age.
The shell is thick and heavy; the umbo of Mr. Hdwards’s specimen (fig. 1, 4) curves
towards the siphonilateral margin, while the specimen from Jermyn Street (fig. 1, a) has
the umbo in the opposite direction. This depends upon the mode of attachment in the
young state, the umbo having been deflected by an impediment. The outer surface of the
lower valve is irregularly rugose and coarsely laminated; the upper valve is much thinner
than the lower, and flat, with the laminze finer and closer.

An oyster from the Nummulitic Formation at Cutch is figured and described under the
name O. callifera by Mr. Jas. Sowerby, ‘ Trans. Geol. Soc.,’ vol. v, pt. 2, second series,
pl. xxv, fig. 16. The Cutch specimen, which I have examined in the Museum of the
Geological Society, does not, I think, belong to this species, and M. D’Orbigny, in his
‘Prod.,’ has named the shell O. Sowerbyana.

The upper valve of an oyster from Uffhofen in the Museum of the Geological Society
is marked with this name, but it would be difficult to determine a species from that valve
alone ; the specimen is peculiar in being excessively thick, and it is perforated in the centre
by the entire abstraction of the shell where the adductor muscle was attached.

M. D’Avrchiac gives this species somewhat doubtingly from the Nummulitic Beds in
the environs of Bayonne.

5. Osrrea cyaTHuLa? Lamarck. Tab. VU, fig. 7, and 'Tab. VIII, fig. 3.

OstRBA CYATHULA. Lam. Ann. du Mus, t. viii, p. 163, No. 12, 1806.
—- _ Desh. Coq. Foss. des Eny. de Par., t. 1, p. 369, pl. 54, figs. 1, 2; ana
pl. 61, figs. 1—4.
— — Id. An.s. Vert. du bassin de Par., t. ii, p. 114, 1860.

Spec. Char. O.‘ testa ovato-rotundata, profundd, incrassatd, solidd ; umbonibus magnis,
posticé inflexis, aliquando contortis ; valvd majore subtus plicata, plicis angustis, distantibus,
radiantibus, lamellis transversis interruptis; valvd superiore pland, transversim striato-lamel-
losd, superné crassa : impressione muscular semi-ovatd, transversd ; fossula cardinali super-
ficialt, transversim striata,”

20 KOCENE MOLLUSCA.

Diameter, 14 inch.

Locality. Stubbington (Ldwards).

In the beautiful work above referred to, now in course of publication by M. Deshayes,
the author gives not less than three varieties of this species, and the British fossil does not
differ in essential characters from one of the varieties of what is considered by the French
author to be a very variable shell. I have, however, placed the British fossil under that
name with a mark of doubt.

6. Ostrea cymBuLérprs, S. Wood. ‘Tab. III, fig. 2, a, 4.

Spec. Char. O. test ovato-oblongd, depressiuscula, valvd inferiore radiatin plicatd, plicis
rotundis, tuberculato-squamosis, subundulatis, bifidis; valvd superiore pland ; marginibus
superne crenatis.

Shell ovately oblong, slightly depressed ; inferior valve radiately plicated, with rounded,
rough, or tuberculated and bifurcated rays; margin crenulated all round in the lower
valve, with lateral crenations on the upper part of the flat valve.

Longest Diameter, 1} inch.

Locality. Werne Bay (Bowerbank).

Although this shell bears considerable resemblance to some of the forms of cymdula,
it cannot satisfactorily be referred to that species, being more regularly ovate in outline, and
more finely costated. It differs from #abel/u/a in several characters, and it does not appear
to have the tendency to angularity or prolongation which that species exhibits ; it has also
more numerous rays. O. divaricata, Lea, somewhat resembles this species, but that shell is
more inflated on what, in the Dimyaria, would be the siphonal region, and there is also,
apparently, a difference in the form of the muscle-mark ; this in our shell is large, reniform,
and somewhat pointed upwards, while in the American fossil it is semi-lunate.

The British fossil appears to be rare.

7. Ostrua porsata, Deshayes. ‘Tab. VI, fig. 2.

Osrrea DorsaTa. Desh. Coq. Foss. des Env. de Par., vol. i, p. 355, No. 22, pl. 55,
figs. 9—11; and pl. 64, figs. 1—4, var. 6; pi. 54, figs. 9, 10.
= — Id. 2d edit., Lam., t. vii, p. 251, No. 42, 1836.
— —- J. Sowerby. Min. Conch., t. 489, fig. 2.
= — Id., in Dixon, Geol. of Sussex, p. 174, 1850.
== = D Orbigny. Prod. de Paleont., t. 11, p. 395, No. 1139, 1850.
= — Morris. Catal. Brit. Foss., p. 174, 1854.

— — Desh. An. sans Vert. du Bassin de Par., t. 11, p. 102, 1860.

Spee. Char. O. testa orbiculata, utrinque gibbosd ; in medio plus minusve subangulatd,
vel semicylindraced ; valvd inferiore converd, extus irregulariter lamellosd; valvé
superiore striata ; striis tenuibus, divaricatis, instructd ; marginibus superné crenulatis.

BIVALVIA. 21

Shell suborbicular ; lower valve convex, and irregularly laminated; upper valve
ornamented with fine, longitudinal, and divaricating strie ; margin of the valve crenulated
above on each side of the hinge.

Dimensions, 5 inches by 4.
Localities. Bracklesham (dwards).
France, Valmondois et Senlis (Deshayes).

This species is not abundant, and it is confined, I believe, to Bracklesham. The
peculiarity of this shell, whence I presume it received its name, is the elevation of the
centre of the upper valve. This arises from an adherence of the animal to some cylin-
drical body, by which a considerable indenture is given to the outside of the lower valve
and an elevated ridge to the inside; this is communicated to the upper valve, in order to
give room to the animal inhabitant, and thus an elevated, semi-cylindrical ridge is on the
outside of the upper valve, corresponding with the body adhered to. Specimens sometimes
occur which have been attached by the greater portion of the lower valve to a flat surface,
and the upper valve in this case has no elevation, but its favorite habit was apparently to
select a cylindrical stem for support. The upper valve is covered with fine strie, and
the interior has the margins crenulated near the hinge; but M. Deshayes figures a specimen
(pl. 64, fig. 3) im which the crenulations have extended round the entire margin of the
upper valve. ‘lhis is not so in the British specimens which have come under my inspection.
The ligamental area is large and broad.

8. OsTREA ELEGANS? Deshayes.

Osrrea ELYGANS. Desh. Coq. Foss. des Envy. de Par., p. 361, pl. 50, figs. 7—9.
=a = J. Sowerby, in Dixon’s Geol. of Sussex, p. 174, 1850.
—- _ J. Morris. Catal. Brit. Foss., p. 174, 1854.

‘This is intermediate in several respects between O. radiosa and O.flabellula, but has
more plaits than the latter. 1 much doubt the propriety of separating it as a species.””—
J. Sowerby.

I am inclined to think with Mr. Sowerby that the English fossil called elegans is only a
variety. There is not any fossil in Mr. Edwards’s collection that deserves to be called
elegans, in specific contradistinction to radiosa, Sow., flabellula, or cymbula ; and as the
above name is given upon the authority of Mr. Edwards’s specimens, it is introduced here
without a figure, and with considerable doubt.

9. OstrEA FLABELLULA, Lamarck. ‘ab. III, fig. 4, a—d.

Cuama piicata. Solander, in Brander, Foss. Hant., pl. viii, figs. 84, 85, 1766.
OsTREA FLABELLULA. Lam. Ann. du Mas., t. viii, p. 164, No. 16; and t. xiv, pl. 20,
fig. 3, a, 5, 1806.

22 EOCENE MOLLUSCA.

OsTREA FLABELLULA. J. Sowerby. Min. Conch., t. 253, 1819.
-- — ? Basterot. Coq. Foss. des Env. de Bord., p. 72, 1525.
=~ — Deshayes. Coq. Foss. des Env. de Par., p. 366, pl. 63, figs. 5—7,
1825.
— — Goldfuss. Petr. Germ., t. 11, p. 14, No. 33, pl. 76, fig. 6, a—g.
— — Galeotti. Mem. de l’Acad. de Brux., t. xii, pl. iv, fig. 6, a, 6, 1837.
— — Nyst. Coq. Foss. Belg., p. 323, pl. 29, fig. 3, a, a’, 6, b', 1843.
— — Bronn. Leth. Geogn., B. iii, p. 352, t. 39, fig. 15, a—c, 1848.
— — J. Sowerby, in Dixon’s Geol. of Sussex, p. 95, pl. 4, fig. 5, 1850.
— — Deshayes. An. sans Vert. du Bassin de Par., p. 120, 1860.

— DEFORMIS. Id. Coq. Foss. des Env. de Par., t. i, p. 346, pl. 55, figs 7, 8.
— SUBPLICATA. Id. - : - - p. 345, pl. 48, fig. 3.
— BIFRONS. Td. 2d edit. Lam., t. vii, p. 242, 1836.

Spec. Char. O. testé cuneaté vel ovato-orbiculari ; valvd inferiore plicatd, plicis
radiantibus, rugosis, arcuatis, hine inde furcatis ; valvd superiore pland concentrice striata ;
intus levi vel obsoleté ad marginem denticulaté.

Shell wedge-shaped or ovately orbicular ; lower valve plicated or ribbed; ribs rugose,
radiating, and bifurcating in the older shell; upper valve flat, concentrically striated, with
the inner margin finely or obsoletely denticulated.

Longest diameter, 13 inch.

Localities. Barton, Bracklesham, Bramshaw, Clarendon, Southampton, Stubbington,
Whitecliffe Bay (Hdwards), Bagshot, Clewett’s Green, Headley on the Hill, Orpington,
Sundridge, (Prestwich).

France, Grignon, Parnes, Courtagnon (Desh.), Bayonne (D’ Archiac).
Belg., Le sables d’Uccle, de St. Gilles, de Foret, de Lacken, &c. (Vys?).

The two specimens from Barton, figured m Brander, Nos. 84 and 85, pl. vu, are
considered by some authors to belong to two distinct species, viz., O. jlabellula and
O. cymbula. |

In Mr. Edwards’s cabinet is a group of these shells from Barton, adhering to each other,
one of which possesses the ovate form of cyméula, while another has the cuneate or typical
form of Ch. plicata, Br., 85; and I cannot imagine that they were otherwise than the
offspring of the same parent, and I believe that the two shells figured in Brander belong
to the same species. Groups of these varying forms are not uncommon also at
Bracklesham.

The English specimens vary much in outline, some being cuneiform or triangular, while
others are oval: this difference does not appear to be the result of impediment to the
natural growth, and it is principally by the outward form that the specific distinction has
been made, the angular one constituting Zadellula, and the ovate one cymbula. Sometimes
this species adheres broadly and firmly to some foreign body, and a large space is left
upon the shell denoting the place of adherence, while in other specimens there is scarcely the

BIVALVIA. 93

slightest mark of attachment. When it adheres to a cylindrical stem the shell is much
elevated, and the form of the body is communicated to the upper valve, giving it a ridge,
like that found in specimens of O. dorsata. In thick individuals the ligamental area of the
lower valve is much elongated, while in thinner shells this space is very short. The upper
valve is plain, never radiated, but has merely concentric lines of growth: sometimes
it is slightly convex, while at others it is irregularly concave or with a depression in
the centre of the shell; it is also sometimes strongly denticulated on each side of the
hinge-area; in one specimen I counted as many as twenty, in others there are scarcely
any. The lower valve also possesses these denticulations more or less, but their number is
no guide in specific determination.

A fossil from the Nummiulitic Formation of Cutch has been figured and described under
this name in the ‘Geol. Tr.,’ vol. v, pl. xxv, fig. 18, specimens of which are in the
Museum of the Geological Society.

O. angulata, fig. 17, on the same plate, comes even nearer in form to flabellula ; it is
possible that they may both be the same as the British species, which was very variable,
and had an extensive range. The specimen, Tab. VIII, fig. 5,7, 6, is from Clarendon, and
although it presents differences, I have regarded it as a dwarf variety (modicella), from
its general resemblance to the typical form. In this shell there is very great inequality
in the two valves.

A specimen of the lower valve of this species has been met with in the Red Crag, at
Sutton, and in good condition. It is therefore probable that the bed which originally con-
tained it, and out of which it was derived, was not very remote from where it was found.

This species is so generally known as a British fossil under the above Lamarckian name,
that I do not feel disposed to change it, although it ought to be called by Solander’s
name, plicata.

10, Ostrua GiGaNTEA, J. Sowerby. PI. IL.

OstfREA GIGANTEA. J. Sow. Min. Conch., t. 64, 1814.

_ — ? Rousseau. Voy. dans la Russie Méridionale, vol. ii, pl. 4, fig. 1.

_ _ ? Leymerie. Mém. de la Soc. Géol. de Fr., 2d ser., vol. i, pl. 17, fig. 2.

= — ? Baily. Foss. Inv., from the Crim. Quart. Jour. Geol. Soc., vol. xiv,
p. 143, 1858.

— .atissima. Desh. Coq. Foss. des Env. de Par., t. i, p. 336, pl. 52 and 53.

— — Galeotti. Mém. Cour. par l’ Acad. de Brux., t. xii, p. 151, pl. 4, fig. 18,

1837.
_ — 2? De Verneuil and Desh. Mém. sur la Crimée, Mem. de la Soc. Géol. de
Fr., t. iii, pt. 1, p. 19, pl. 4, figs. 1—3, 1838.

— Pyrenatca? D’Orhigny. Prod. de Palzont., t. ii, p. 517, No. 548, 1850.

— iGantica. Solander, in Brand., Foss. Hanton., p.36, No. 88, pl. 8, fig. 88, 1776.

— _ Nust. Coq. Foss. de Belg., p. 314, pl. 27, fig. 16; pl. 28, fig. la,
1843.

— _ Desh, An. sans Vert. du Bassin de Par., t. i, p. 108, 1860.

24 EOCENE MOLLUSCA.

Spec. Char. O. testa magna, crassissimd, ovato-circulari, inequvalvi, irregulariter
lamellosaé ; valvé inferiore gibbosd, convexd ; valvd superiore pland, impressione musculari
sublunari, profundd ; umbonibus brevibus; cardine plano-triangulari, striato, foveold
profundd ; marginibus superne rugoso-plicatis.

Shell large and thick, ovately circular, mequivalved, irregularly lamellated ; inferior
valve gibbous and convex ; upper valve flat; muscle-mark gibbosely lunate; beaks short,
hinge area flattened and triangular, deeply marked with lines of growth; rugosely plicated
on each side of the hinge.

Diameter, 6 inches.

Localities. Bognor, Barton (Hdwards), Cuffell near Basingstoke (Prestwich).

Belgium, Kleyn Spauwen; Picétrebais, pres de Chapelle St. Laurent
(Myst) ; Middle Limburg (Zyel/).
France, Chaumont, Valmondois (Deshayes).

M. Bronn (Leth. Geogn., b. 11, p. 355) has considered the fossil found in the Crimea,
called gigantea by MM. De Verneuil and Deshayes, as a distinct species, to which he has given
the name of O. Pyrenaica ; and he is not alone in this opinion. If the figure by M. Deshayes
represents its constant character, the muscle-mark appears to be not only of a different
form, but to be situated nearer to the hinge than in our specimens. Form, in this genus,
is of itself a character by no means to be depended upon, as the shell is frequently
distorted.

Fig. 6, Tab. VIII, appears to me to possess the characters required for a place in this
species. The principal difference is in the shape ; the lengthened beak, and elevated muscle-
mark, are consequent upon its peculiar form ; but the cicatrice is of a different colour from
the shell, as is usual in gigantea. The rugosities, or denticulations, at the shoulders which
distinguish this species are not very evident, although there are traces of them, and they
are perhaps destroyed.

Mr. Sowerby, in Dixon’s ‘ Geology of Sussex,’ pp. 95 and 173, introduces an oyster under
the specific name elephantopus ; and, after giving a full description, but no figure, says,
“This differs from gzgantea in the form of the hinge-pit, which is considerably elevated in
that species, and in the depth of the hollow valve. It shows the same cellular tissue as
O. cariosa of the Bognor Rock, which may possibly be the young of the same species,
although such large specimens have not been found at that place.”

The specimen to which the name elephantopus is attached in the late Mr. Dixon’s collee-
tion in the British Museum is an upper or right valve of great solidity; but it does not appear
to me to offer any character that will separate it from gigantea, to which I believe it belongs.
‘The peculiarity of the hinge in extending inwards is the result of the excessive thickening
of the shell, by the successive layers of calcareous matter over the entire surface of the
interior. Similar specimens are in the cabinets of Mr. Edwards and Dr. Bowerbank, and
I am unable to detect any other difference than that which has been produced by age.
These shells possess the same peculiar structure, as is so strikingly displayed in some

BIVALVIA. 25

specimens of the upper valve of gigantea, from Barton. ‘This structure is not, in general,
so evident in the lower or left valve, where the exterior generally appears foliaceous ;
but the carious structure may be observed, where there is a fracture.” The Barton
specimens appear to have adhered broadly. Dr. Bowerbank’s specimen, from
Bracklesham, exhibits scarcely any mark of attachment. One of my specimens,
from Barton, had been fixed to a cylindrical body, which has imparted to the upper valve
a semi-cylindrical elevation like that characteristic of dorsata, which it much resembles ;
and the outer surface, where it is preserved, is covered with fine radiating stria, which
are occasionally in ridges, like those represented upon O. oblonga, Brander, PI. VII, fig. 83.
I suspect that this last specimen was only an imperfect individual of the present species.
There is a great tendency to thickening of the shell in those from Bracklesham. One
aged specimen in Dr. Bowerbank’s museum has the following dimensions :—diameter, 5
inches by 4, thickness of shell in this lower valve, two inches and four tenths. O. callifera
(from Cutch), J. Sowerby (Tran. Geol. Soc., vol. v, pl. 11, second series, pl. xxv, fig. xvi),
is a shell in that state, probably belonging to this species.

Ostrea cariosa is given by Professor Morris, in his catalogue, as a British fossil ; and it
is also introduced by Mr. J. D. C. Sowerby, in Dixon’s ‘ Geology of Sussex,’ pp. 117, 226;
I have not seen a specimen on which this specific isolation might be founded. May it
not be the young state of gigantea ? as suggested by Mr. Sowerby.

1]. Osrrea GrypHovicina, S. Wood. ‘Tab. VII, fig. 6, a, 6.

Spec. Char. O. testé crassa, ovata ; valvd inferiore tumidd, profundd, obsolete lamellata ;
valvd superiore planiusculd, nuda ; cardine magno, trigono, fossula ligamenti angustissimd,
excavald ; marginibus integris ; tmpressione musculart subrotundd, parva.

Shell thick, ovate; lower valve tumid and deep, with almost obliterated lamelle ;
upper valve flattened and nearly smooth; hinge area broad, with a long, narrow, and
deep ligamental furrow ; margins free from crenulations; muscular impression round and
small.

Height, 2% inches.

Localities. Sheppey (Bowerbank), Hampstead (WVetherell).

The peculiarly deep, contracted, and elongated ligamental pit in these shells differs from
any other that I have seen, and gives reason to believe that they belong to a distinct species ;
the shape of the muscle-mark appears also to be different from any other. In the specimen
belonging to Mr. Wetherell there is an obtuse lateral lobe separated by a shallow sinus

* On requesting Dr. Carpenter to give me his opinion upon this peculiar appearance, he says :—“ I think it
likely that the structure you allude to is one which I have seen in various large oysters, both recent and
fossil, and which was first noticed, I believe, by Dr. J, E. Gray, namely, a cancellated tissue filling up the
space that would otherwise be left empty between separated Jamelle.”’

4

26 EOCENE MOLLUSCA.

on the siphonal region, like the character generally given for Gryphea, and on the tablet
of Dr. Bowerbank’s specimen was written the name of Gryphea ; I cannot see any-
thing to distinguish it generically from Ostrea, except the very small place of attachment,
which of itself is insufficient.

12. Ostrua 1nrLAtA? Deshayes. Tab. VII, fig. 4.

Osrrea INFLATA. Desh. Coq. Foss. de Par., t. i, p. 359, pl. 58, figs. 4, 5, and pl. 59,
figs. 1, 2, 1825.
= = J. Sow., in Dixon’s Geol. of Suss., p. 95, t. iv, fig. 7, 1850.
— — Morris, Catal. Brit. Foss., p. 174, 1854.

Spec. Char. “O. testa ovato-deformi, profundd, gibbosd ; valvd inferiore rariplicata ;
umbone angusto ; fossuld lgamenti angustd, marginibus superné crenatis.”’

Shell deformedly ovate, deep, inflated (?), lower valve with few radiating ridges,
umbones sharp, ligamental area narrow, superior margins crenulated.

Longest Diameter, 15 inch.

Localities. Bracklesham (#dwards).

France, Valmondois (Deshayes).

This is not at all a satisfactory species. I have only two or three specimens from
Mr. Edwards’s cabinet that appear to correspond with the above diagnosis of M. Deshayes,
They are left valves, and have adhered, near the margin of the shell, to some cylindrical
body ; they are by no means “ inflated,” but shallow. The shell figured by M. Nyst, under
this name, appears to be very different from the British specimens.

13. Ostrea LonctrostRis, Lamarck. ab. VI, fig. 4.

OstREA LONGIROSTRIS. Lam. An. du Mus., t. 14, pl. 21, fig. 9.
— — Desh. Coq. Foss. de Par., t. i, p. 351, pl. 54, figs. 7, 8; pl. 60,
figs. 1—3; pl. 61, figs. 8, 9; pl. 62, figs. 4, 5; and
pl. 63, fig. 1.
—- — J. Sow., in Dixon’s Geol. of Sussex, p. 174, t. iv, fig. 4, 1850.
— Morris. Catal. Brit. Foss., p. 175, 1854.
— Desh, Hist. des An. sans Vert. du Bass. de Par., t. ii, p. 110, 1860,

Spec. Char. O. testa diversiformi, ovato-rotundatd, vel elongato-irregulari ; foliaced,
Y) e A ee . . . A he . a
rugosa, incrassata ; strits lamellosis transversis instructd ; valud inferiore profundd ; umbone
longissimo, canaliculato, irreguluriter contorto, acuto, trigono, tenué-striato vel sulcato ;
fossuldé utroque latere marginatda.
Shell variable, ovately rounded, or elongately irregular, foliaceous, rough, and very thick ;
inferior valve deep, with a very elongated ligamental area strongly marked with transverse

strize or lines of growth.

*)
~I

BIVALVIA. 2

Dimensions, 4 ches by 2.

Localities. Hempstead (Ldwards), Bracklesham (Divon).

France, Montmartre, Sceaux, Longjumeau (Deshayes).

There are two or three species in this genus which have an extended ligamental area,
and are equally deserving of the present or a similar appellation.* The fossil oyster from
Lisbon has the hinge area as long as that of the Hocene species, and it has also been called
longirostris, but the shape of the shell is very different. ‘The recent American oyster
O. Virginica (O. crassa, ‘Chemn.,’ vol. vii, p. 40, t. 74, f. 678), has a similar character,
but is, I think, distinct.

The present species does not appear to have been abundant in the British Eocene
Seas, and I have not seen the upper valve; M. Deshayes speaks of the French shell as by
no means rare, and he gives four distinct varieties of his species. Philippi (En. Moll.
Sic.,’ vol. i, p. 64) introduces O. /ongirostris as a fossil from Syracuse, but he does not
give a figure ; he quotes Goldfuss, as well as Deshayes.

14, OsTREA MARGINIDENTATA, S. Wood. ‘Tab. V, fig. 2, a—d.

OstREA RADIOSA. J. Sow., in Dixon’s Geol. of Sussex, p. 174, 1850.
— — Morris. Catal. Brit. Foss., p. 175, 1854.

Spec. Char. O. testa ovata vel orbiculatd, crassa ; valvd inferiore plicald, plicis squa-
mosis, radiantibus ; valvd superiore pland ; marginibus valdé crenulatis vel denticulatis ;
impressione musculart magna.

Shell ovate or orbicular, thick, and strong ; lower valve plicated, with radiating and
rough ridges or ribs ; upper valve flat and plain, margin crenulated, muscular impression
large and slightly curved or reniform.

Diameter, 34 inches.

Locality. Bracklesham (dwards.)

This is by no means rare. Among Mr. Edwards’ specimens there is great variation.
Fig. 2, d, resembles the form and most of the characters of O. extensa, as given
by M. Deshayes. Many specimens from Bracklesham have adhered by a large surface,
extending over nearly the whole valve ; in these cases the interior is shallow, and the shell
is more orbicular ; when the adherence is by a small portion of the surface or by the beak
only, the valves are then more elevated and deeper. I have given a view of the interior
of both valves, to show the difference in form of the adductor muscle-mark. In the
specimen, fig. 2, a, the animal has extended the shell into a sort of shoulder; and the
adductor muscle has followed the course taken by the mantle; from this distortion the
muscle-mark is much altered.

* T have retained the name of longirostris for this species, as it is presumed to be identical with the
Paris Basin shell, which was the one originally so called.

28 EOCENE MOLLUSCA.

‘his fossil has been hitherto assigned to O. radiosa, Desh., and I feel reluctant to alter
the name ; but the large denticulations which are found invariably, in a greater or less
degree, on the inner margin of the upper valve in well-preserved specimens, appear to offer
a good specific character in contradistinction to the French shell of that name.

15, Ostrea Mutticostata? Deshayes. Tab. VI, fig. 3, a, 6.

Os?REA MULTICOsTATA. Desh. Coq. Foss. des Env. de Par., p. 363, pl. 57, fig. 3—6.
— — Bronn. Leth. Geogn., b. iii, p. 352, t. 362, fig. 6, a, e.
— — ! D’Archiac. Anim. Foss. numm. de V’Inde, p. 273, pl. 24, 1854.

Spec. Char. O. testa ovato-elongatd, subrectd, superné acutd ; valud inferiore costatd,
costis divergentibus ; valvd superiore planulatd, lamellis tenuibus, concentricis, ornatd ;
rmpressione muscular: obliqua.

Shell ovately elongate, somewhat straight, with an acute umbo; lower valve covered
with diverging ribs which bifurcate on the outer or older portion of the shell; upper
valve flat, with small or fine concentric lamine or lines of growth ; muscular impression
oblique.

fTeight, 3 inches.

Locality. Bracklesham (Ldwards).

France, Retheuil (Des/.).

A specimen in Mr. Edwards’ collection corresponds with the figure and description by
M. Deshayes above referred to, and I have therefore regarded it as an identity, although it
is possible it may only be an enlarged growth of one of the Bracklesham varieties of fabellula.
This is said to be abundant in France, where I presume there are better means of deter-
mining the species. ‘The umbo in our shell is sharp and pointed, and the place of
attachment is very small. ‘The upper valve is plain, or without the least appearance of
radiating strie. The muscle-mark is of a somewhat transversely ovate form, excentric,
and appears rather smaller, comparatively, than the one represented by M. Deshayes; the
ribs in our shell are smoother or less scaly; these trifling differences would probably

disappear in a large series.

16. Osrrea picra, J. Sowerby. ‘Tab. VII, fig. 2.
OstreEA Picta. J. Sow., in Dixon’s Geol. of Suss., pp. 25, 173, t. iv, fig. 1, 1850.
— — Morris. Catal. Brit. Foss., p. 175, 1854.

Spec. Char. O. testa crassa, orbiculari, intus purpureo-nigricante, lamellis vie distinctis ;
valvd inferiore profunda, valvd superiore planatd ; ared cardinali latd ; impressione musculari
magna, suborbiculari.

BIVALVIA. 29

Shell thick, orbicular, uneven, not imbricated; lower valve deep, upper valve nearly
flat ; hinge area broad and flat, muscular impression large and orbicular; both valves
coloured within.

Diameter, 34 inches.

Locality. Bracklesham (Dizon).

“Colour is so rare an occurrence among oysters, and especially among fossils, that we
are glad to accept it for a specific mark. The present shell belongs to a section of the
genus which contains species whose surfaces are not imbricated, but covered by a con-
tinuous plate of a fibrous structure; in this the structure is, however, obscure; in O.
tabulata and O. dorsata, &c., it is very easily detected. Old shells seem to be imbricated
because the edges of the Jamie are worn away. ‘The surface of the young shell, well
shown in an individual which has been attached to a large MVautilus, is nearly smooth,
but irregularly marked with distant, short, interrupted striae ; the hinge area projects into
the cavity of the shell.” —Sowerdy.

This species is rare, and colour appears to be its most distinguishing character.
The upper valve exhibits some depressed, broad, irregular, and rather obscure radia-
tions, separated by a small depressed line and coloured rays; the lower valve shows
a broad mark of attachment ; and the shell is somewhat compact, with fine lines of growth
and small or incipient lamella, but it is less laminated than gigantea, which it otherwise
much resembles ; the muscle-mark is transversely rounded, and of the form usuall y assumed
in the orbicular oysters.

17. Ostrea prona, 8S. Wood. ab. III, fig. 3, a, 6.

Spec. Char. O. testd crassa, obliqua, cuneata ; valvd inferiore tumidd, inflaté, profunde
plicatd, plicis radiantibus hine inde furcatis, elevatis, angulatis ; valvdé superiore planata ;
cardine introrsum recurvo.

Shell thick, strong, oblique, and wedge-shaped ; lower valve tumid, inflated, and deeply
plicated ; folds radiating, elevated, angulated, and bifurcated ; upper valve flat, plain ; umbo
inflexed.

Diameter, 22 inches.

Localities. Brockenhurst, Lyndhurst (Hdwards).

This shell is by no means rare in Mr. Edwards’ cabinet. ‘The young of this species
strongly resembles O. flabellula, and like other species in several genera, the immature shell
can scarcely be distinguished from some proximate species of less magnitude. I think, how-
ever, there is sufficient difference in the full-grown individual to justify its specific separa-
tion. ‘The ribs or folds in this species are perfectly angular in well-preserved specimens,
while in fabellula they are obtuse or rounded ; this difference is its principal distinction.

30 EOCENE MOLLUSCA.

An oyster from Kleyn Spauwen was obligingly sent to me some years ago by the
Comte du Chastel, but without a name. ‘The specimen is, I believe, identical with the
Brockenhurst shell ; it resembles it even in colour.

18. Osrrea putouRA, J. Sowerby. Tab. I.

OsTREA PULCHRA. Jd. Sow. Min. Conch., t. 279.
— — Morris. Catal. Brit. Foss., p. 175, 1854.

Spec. Char. O. testé magna, orbiculato-ovatd, crassa, depressd ; valvd iferiore
convexd, lamellatd, in juventute plicaté vel costatd; valvd superiore planata ; cardine
brevissimd ; impressione musculart ovato.

Shell large, roundly ovate, thick, depressed; lower valve convex, lamellated, and
plicated or costated in the young state; upper valve plain and flat, hinge very short ;
muscular impression ovate.

Diameter, 7 inches.

Localities. Reading, Clarendon (Hdwards).

Small var. Bromley, 'Tyler’s Hill near Chesham, Old Basing (Prestwich). |

‘This species differs from O. Bellovacina in beg more numerously rayed or costated
in the lower valve of the young shell; these ridges become nearly obsolete as it
advances in age, and the upper valve is naked, or free from radiating ridges. The
Reading specimens are generally orbicular, those from Clarendon have the greatest diameter
from the umbo to the ventral margin.

In the Reading specimens many have the two valves united, and the ligament preserved ;
the small shell figured Tab. IV, fig. 2, a, 6, is the representation of what I imagine
to be the young state of the upper or right valve of this species from Clarendon;
the umbo is much recurved or inflected after the manner of Gryphea or Hvogyra, and
on each side of the hinge the margin is crenulated or denticulated ; this character may
be seen in some of the large and full-grown specimens of this species from Clarendon.
Mr. Edwards’ specimen of this species from Reading measures seven inches and a half
in the longest diameter, and I think the animal inhabitant must have attained to the
dimensions of at least six inches, with a depth of rather more than one inch. ‘The shell
figured in ‘Min. Conch.’ from Bromley, above referred to, represents what I believe to
be a small variety of this species, and the same kind is also found at Sunning Hill.

BIVALVIA.

oe)

19. Ostrea TaBuLATA, J. Sowerby. ‘Tab. IV, fig. 1, a, 4.

OstREA TABULATA. J. Sow., in Dixon’s Foss. of Suss., pp. 117, 226, 1850.
— — Morris, Catal. Brit. Foss., p. 175, 1854.

Spec. Char. Testé orbiculatd, depressa ; laevigata ; valvd inferiore imbricatd obscuré
radiata ; valvd superiore pland, nitidd, politd ; umbonibus parvis.

“Shell orbicular, depressed, smooth ; upper valve slightly concave, even, its plates few,
with distant, scarcely raised edges ; lower valve obscurely marked by radiating undulations,
its plates few, in groups, with remote, deeply imbricating edges; beaks small, pointed ;
muscular impression ovate, curved, of a moderate size.”—Sowerdby.

Diameter, 7 inches,

Locality. Bognor.

This is an abundant shell at Bognor, to which locality it appears to be restricted.

Mr. Sowerby remarks “ that it was evidently a rapid growing shell; its nearly smooth
external lamine extend far between each period of growth, and show their fibrous
structure distinctly, especially upon the surface.” The specimens generally have
adhered only in the young state by a very small portion of the surface, and are
solitary. I have rarely seen them in groups. A specimen in Mr. Wetherell’s
cabinet shows the muscle-mark to be rather elongate, and more curved than is the rounded
form of this mark in gigantea. 'The lower valve in the young state is obscurely rayed,
and the upper is generally glossy, and the shell is flatter or more compressed than that of
gigantea.

20. Ostrea tenERA, J. Sowerby. ‘Tab. VI, fig. 1, a, 6.

OstREA TENER. J. Sow. Min. Conch., t. 252, figs. 2, 3, 1819.
— eENERA. Jd., in Dixon’s Foss. of Suss., p. 174, t. iv, figs. 2, 3, 1850.
— — D’ Orbigny. Prod. de Paleont., t. 1, p. 307, No. 199, 1850.
— — Morris. Catal. Brit. Foss., p. 175, 1857.

Spec. Char. Testa elongatd, attenuatd, angustd, depressd valvd inferiore sub-pland,
transversim lamellosd, valvd superiore striatd vel inornatd ; umbonibus longis attenuatis ;
Jossuld ligamenti angusta.

Shell elongate, attenuated, depressed ; lower valve very slightly convex and transversely
lamellated ; upper valve flat, striated, or plain ; umbones attenuated, ligamental ; area long
and pointed.

Height, 4% inches.

Localities. Woolwich, Sundridge Park, New Cross, smooth and thick var. (Prestwich).

Bracklesham, thin and striated var. (Hdwards).

32 EOCENE MOLLUSCA.

“The Woolwich type of this species is generally smooth ; but I have reason to think that
the fibrous striated coat is more easily decomposed than the other laminee of the shell, and
has been therefore generally destroyed. Such appears to have been the case often with the
Bracklesham individuals ; however, some of the latter, having the fibrous coat, are almost
free from striae, and others want them over more or less of the surface, which has induced
me to consider the striated ones as only varieties of the others.” (Sowerby in Dizon.)

In support of the above remark, I may observe, that some of Mr. Edwards’ specimens
from Bracklesham show the upper valve to be quite free from ornament; others are
fully covered over with numerous fine striz; and one specimen unites these two varieties,
the younger half of the upper valve being covered with striz, and the lower or older por-
tion being quite plain; both parts are apparently without decortication.

O. angustata, Desh., in many characters strongly resembles this species ; but it appears
rather more attenuated in the hinge than any of our British specimens, although such a
difference as this may be accidental. In the representation of the French shell are a few
depressed and irregular ribs, and the shell is free from striae, but there are vestiges of
radiating plicee or obsolete ribs in our species.

The full-grown specimens may be said to have proportions generally of about three to
one, but a full-grown specimen in Mr. Edwards’ cabinet is not more than two to one anda
half. In the young state the shell is often nearly orbicular, becoming elevated as it increases
in size. One of our specimens has a very pointed umbo, and this is somewhat recurved.

21. Ostrea VectiEensis, Forbes MSS. ‘Tab. VII, fig. 5, a—c.

OstreA VeEcTENSIS. Morris. Mem. Geol. Surv. pp. 68, 150, t. 3, fig. 9, 9 a, 9 6, 1856.
— = Id. Cat. Brit. Foss., p. 175, 1854.

Spec. Char. “ Testa ovato-trigond, oblonga, attenuatd, sub-angustd ; ared cardinali
fossuld triangulari, lata, recurvd exaraté ; umbonibus obtusis ; valvd superiore lineis incre-
menti numerosis ornatd ; valvd majore crassa, extus rugosa.”

An oblong and rather narrow shell, with the larger valve somewhat thick and externally
rugose ; the upper valve flat, thin, recurved at the umbo, and marked by numerous con-
centric lines of growth; ligamental area broad and triangular.” (Morris.)

Longest diameter, 15 ch.

Locality. ‘‘ Sandy beds of the Bembridge series.” (Jorris.)

This species does not appear to be rare; several specimens are in the Museum in
Jermyn-street.

The right valve has occasionally crenulations in the margin near the hinge; but
as this valve is often quite free from them; the form of the shell is also exceedingly

BIVALVIA. 33

variable. Fig. 5, c, resembles O. Sparnacensis, Desh. (pl. 64, figs. 5—8.) The hinge (which
is peculiar) is very similar, although, if that figure be correct, the muscle-mark is not so elon-
gated as in our species, Fig. 5, 4, is, I imagine, the lower valve of a specimen belonging to
this species, and its recurved umbo gives it the appearance of a Gryphea. None of the
specimens in Jermyn-street possessed, that I could see, the radiations spoken of by M.
Deshayes as distinguishing O. gryphina ; and there is no diagnosis or any remark by the
late Professor E. Forbes, on whose authority that species is introduced (Mem. Geol.
Survey., 1856, p. 88.) I am therefore unable to consider Gryphina as a British
species.

22. OsrrEA veLata, S. Wood. Tab. VII, fig. 1, a, 6.

Spec. Char. Testa ovato-trigond, sub-obliquaé ; ared cardinali latd, incurvd ; valva
inferiore lamellatd ; lamellis subregularibus, fimbriosis ; valvd superiore planulatd, striata ;
striis magnis, undulatis.

Shell ovately trigonal, somewhat oblique ; cardinal area rather broad, incurved ; inferior
valve lamellated, the lamellz in general regular, fimbriated, or projecting ; upper valve
flattened and striated, strize large and undulating.

Diameter, 2 inches.

Localities. Colwell Bay (Zdwards), Whitecliffe Bay (Prestwich).

This is rather a pretty looking shell, and does not appear at all rare. Its great
peculiarity consists in being striated upon the upper valve. ‘The striation in our specimens
exists only in the outer coating of the upper valve; this coating is sometimes entirely
removed, and is seldom seen except in patches. I thought at one time it might have
belonged to cochlearia, and that the French specimens had lost this outer cuticle; but
there are no “obscure plications’ in the lower valve, which the French fossil is said to
possess, but it is regularly lamellated or fimbriated. I have, therefore, with reluctance
felt compelled to give it anew name. ‘The upper valve of this species, much distorted, I
found, many years ago, in the small patch of marine shells which intervenes between the
fresh-water deposits on the Hampshire Coast, at Hordwell. 0. cochlear. Poli, is a recent
species, and is quite distinct. O. cochlear., Nyst (p. 330, pl. 32, fig. 2), which he gives as a
fossil from Hoesselt and Lethen, in the Limburg, appears from figure and description, to be
different from any oyster that I have seen from the older Tertiaries of England.
Cochlearia is a name attached to several specimens of Osérea in the Museum in Jermyn-
street; but these specimens appear to me to belong either to Vectensis or to this species.
In the second part of ‘ Coq. Foss. des Env. de Paris,’ t. 2, p. 114, the author considers his
former species of O. cochiearia as a variety of O. cyathula.

5

34 EOCENE MOLLUSCA.

23. Osrrea zonuLata, S. Wood. Tab. X, fig. 4, a—ec.

Spec. Char. O. testa elongato-ovatd, tenui, fragili, valvd sinistraé convead, profunda,
imbricata ; imbricibus tenuibus, distantibus ; valvé dewtrd pland, lamellaté ; cicatriculd
musculari minima, reniformi ; ared cardinali angusta.

Shell elongately ovate, thin, and fragile ; left or lower valve convex, deep; upper valve
flat and lamellated, lamellz or fimbriations thin and distant; muscular impression small ;
cardinal area narrow.

Longest diameter, 14 inch.

Locality. Till Head, near Stubbington. (Fisher.)

The above shell has been recently obtained by the Rev. Osmond Fisher, who has kindly
permitted me to have it figured.

It somewhat resembles O. velata in the regularity of the imbrications, but it differs in
having these imbrications fewer in number, and they are broader, more thin, and delicate ;
besides which, the upper valve in this species is quite free from the strize which form
so marked a feature in the upper valve of O. velata.

Fig. 4, Tab. VIII, represents a specimen of the upper valve of an oyster, from the
cabinet of Mr. Edwards, and found at Bracklesham. ‘This was figured previous to the
discovery of the above species, and it was then considered so closely to resemble the French
Eocene fossil, O. /amellaris, Desh. (Coq. foss. des Env. de Paris, pl. 54, figs. 3, 4), as to
deserve a representation, from a possible identity ; but in the subsequent work by the same
author (An. sans Vert. du Bassin de Paris, t. xi, p. 106), that shell is referred to 0.
multistriata, in which species the upper valve is represented as finely and closely striated.
Our shell is quite free from strize of any kind, and it does not appear to have been decor-
ticated. I am now therefore inclined to refer it to the present species.

In the ‘ Quarterly Journ. of the Geol. Soc.,’ 1854, p. 117, Mr. Prestwich speaks of an
oyster as having been met with at Kyson (O. Bellovacina ?); but the specimen cannot be
found. Mr. J.C. Moore obtained an oyster in an estuary deposit in the New Forest.
‘Journ. Geol. Soc.,’ vol. v, p. 316, 1849. This specimen also we have not been fortunate

enough to find.

BIVALVIA. 35

VULSELLA. Humphries, 1797.

TELLINA (sp.) Rumph., 1705.

Pinna (sp.) Linn. 1758.

Mya (sp.) Id. -

Baputa (sp.) Gevers, 1787.

Ostrea (sp.) Brug., 1789. D’Ord., 1850.
Vuutsewua. Lamk., 1799.

Daracta? Gray, 1825.

RENIELLA. Swains., 1840.

Gen. Char. Shell somewhat irregular, elongated, compressed, inequivalved, free ;
hinge with connexus external or ligamentous; umbones straight, remote, earless; one
muscular impression in each valve, subcentral,

This is a genus containing but few species, either in the recent state or as fossil.
Six recent species have been described, and these are confined to the Oriental seas.

Lamarck had placed this genus close to Os¢rea, to which in many of its characters it
bears a great resemblance ; it is truly monomyarian, and the connexus is situated as in the
oyster, between divergent beaks upon an inclined plane, opening the valves by contraction.
Cuvier removed it from that position to one in proximity with J/a//eus ; and some authors
still consider it only as a section of, or sub-genus to, Avicuwda. Judging from the shell alone, in
the absence of a knowledge of the animal, the differences are too conspicuous to be included
in that genus, and it appears to me entitled to claim an isolation equal to many other
generally admitted genera.

Shells bearing the above generic characters have been found in the Chalk.

1. VunseLLA DEPERDITA? Lamarck. Tab. IX, fig. 2, a—e.

VULSELLA DEPERDITA. Lam. Hist. des An. sans Vert., t. vi, p. 222, No. 7.

a Defrance. Dict. des Sc. Nat., art. Vulsella.

-— — Desh. Coq. Foss. des Env. de Par., p. 374, pl. 65, figs. 4—6.
— Id. An. sans Vert. du Bass. de Par., t. 2, p. 51, 1860.

— ? Grateloup. Cat. des An. Foss. des Eny. de Bord., p. 59, 1838.
_— Morris. Cat. of Brit. Foss., p. 182.

OsrrEA DEPERDITA. D’Ord. Prod. de Paleont., p. 394, 1850.

Spec. Char. Testdé ovato-oblongd, angustd, inequivalud, sub-lingulatd, sublevigatd,

of : ; ites derrete

superne tumidiore, apice retusa ; fossuld cardinal magna, oblique incumbente, lateral,
basi prominuld; ared cardinali sinuato ; impressione muscular sub-laterali, elongato-

ovata.

36 EOCENE MOLLUSCA.

Shell ovately oblong, elevated, and somewhat tongue-shaped, depressed and inequivalved,
tumid at the upper part, with very divergent umbones ; shell subnacreous, irregularly smooth
with conspicuous lines of growth and a sharp margin, base prominent and rather pointed ;
muscular impression elongated.

Longest diameter, 13 inch.

Localities. Barton (Hdwards).

France—Grignon, Chaumont, Mouchy, le Chatel (Desh.), Blaye, (Grate/).

The hinge-area in the British fossil has apparently a larger ligamental depression, and
a smaller sinus than is represented in the French shell; but these differences would
probably vanish on a comparison with specimens of the shells themselves. The connexus
is somewhat on one side of the hinge-area, as if counteracting the action of the adductor
muscle which is on the other. The left valve extends the ventral margin beyond the edge
of the right, making the shell mequivalve, like the oyster.

The above name has been published for an English fossil, and, as I have not the means
of disproving the identity, I have permitted it to remain with a mark of doubt. The shell,
like most of the oyster tribe, has a tendency to great variation, and the muscle-mark
partakes of the varying form of the shell. Since the above was written, I find the follow-
ing observation by M. Deshayes, in ‘ Hist. des An. sans. Vert du bassin de Paris,’ p. 51:
—<TL’espéce est citée dans le bassin de Londres par M. Morris; mais a Barton elle est
accompagnée d’une autre trés-distincte, beaucoup plus rapprochée par ses charactéres d’une
espéce vivante de la Mer Rouge, et d’une autre fossile du terrain nummulitique de l’Inde
que M. d’Archiac a fait connaitre sous le nom de Valsella lignium.”

I have made every effort to see the specimens here referred to, but without success.
I am not aware that the genus has been found in the London basin, or anywhere but at
Barton ; and all the specimens that I have seen may, in my opinion, be referred to one
species, but whether that be the true deperdita I cannot say.

PECTEN. Plany, Aldrovandus, &c.

Ostrea (sp.). Linn.—P. opercularis, Sect. a.
Hinnites. Sow. (not Defr.).—P. pusio, ,, 38.
JANTRA. Schum.—P. maximus, sane:
Neituea. Drouet.—P. quinquecostatus, ,, d
PLEURONECTIA. Swains.—P. pleuronectes, ,, e.

Gen. Char. Shell lenticular or sub-orbicular, sometimes ovate, sub-equilateral, gene-
rally inequivalve ; ornamented with radiating striae or more or less elevated ribs : beaks ap-
proximate and acute, with a projecting and unequal auricle on each side of the umbo ;
pedal region slightly sinuated, right valve generally the more convex ; connexus bipartite, the
ligamental portion narrow on the straight hinge-margin, cartilage placed in a central pit,

BIVALVIA 37

elongately triangular; impression of the adductor somewhat obscure, excentric ; double
pedal impression visible in right valve, obsolete in the left; impression of the mantle
not well defined.

Animal, with the edges of the mantle disconnected all round except at one part, which
serves to separate the inhalent from the excurrent canal; margins double, each bearing a
row of tentacular filaments, and at the base a row of black eyelets (oce//7) ; foot small,
sub-cylindrical or digitiform, grooved, and byssiferous in the young state.

This constitutes a well-marked group, although the species present considerable
diversity of character in their exterior ornaments. ‘The valves are generally covered with
radiating ribs or striz, and in the very imequivalved species, of which P. maximus is the
type, the rays are large and elevated, while at the other extremity, such as P. plevronectes,
the valves are nearly smooth, though still preserving the outward form and other
characteristics of the genus.

The foot of the animal is very small and incapable of being extruded, and probably
the only use it makes of this organ is to spin a byssus, which is employed principally in the
young state; im some species, the animal when more advanced in age is capable of
considerable locomotion." In Chemnitz ‘Conch. Cab.,’ vol. vii, p. 261, vig. xi, there is
a woodcut which represents the dmaginary animal of Pecten (opercularis?) with two
distinct and separated siphons, prettily ornamented with setze or fibrillee projecting beyond
the margin of the shell, and a large geniculated foot is protruding to some distance in an
opposite direction.

There is always more or less difference in‘the magnitude of the two valves in the shells
of this genus, but it isin those species which lie habitually on one side that the great
inequality is most distinct ; the convex or tumid valve, being buried in the sand or mud,
is usually colourless or fainter in ornament than the upper or flat valve, which is always
exposed to the light.

The genus has a very extensive vertical range, the British species having been obtained
alive by Mr. M‘Andrew from the shore to the depth of 150 fathoms, though the most
frequented habitats of two edible species, maaimus and opercularis, are upon banks that
do not extend beyond the range of thirty fathoms. Its geographical range is very
extensive.

1 The stationary habit of this genus is generally by means of a byssus; there is one species
P. pusio of British authors, which fixes itself by the outside of the shell, like the oyster, but, unlike that
genus, it employs the right valve, or that in which is left a sinus for the byssus ; sometimes the whole of
this large valve is soldered to the rock. In this it is connected with Hinnites (Defr.), which, how-
ever, is very different in all other respects. I have not seen a fossil Pecten possessing such a habit.

38 EOCENE MOLLUSCA.

1. Pecren Benuicostatus, S. Wood. ‘Tab. VIII, fig. 11, a, 4.

Spec. Char. Testa crassa, equivalvi, orbiculari vel lenticulari, equilaterali, costatd ;
costis 20-24 sub-rotundis, striatis et imbricatis; interstitiis lineatis et imbricatis ;
auriculis magnis, inequalibus.

Shell thick and strong, equivalved, orbicular or lenticular, equilateral, costated ; ribs
20 to 24 somewhat rounded, striated, and strongly imbricated; interspaces also with
imbricated rays : auricles large and unequal, one costated, the other striated.

Diameter, 12ths of an inch.

Locality.— Brockenhurst (Ldwards).

Our shell is a handsome one and highly ornamented, and, judging from the number
of specimens in Mr. Edwards’ cabinet, it does not appear to have been scarce. In addition
to the above formula, it may be further noticed, that the centre of the elevated rib is not
only strongly and regularly imbricated, but the imbrices are long, overlapping, and
slightly projecting ; they are not reflexed, but lie over each other like ornamental tiling ;
there is a smaller ray on each side of the centre one, which is also imbricated, and the two
lines or rays on the interspaces are likewise covered with small imbrications. The auricle
on the pedal side of the right valve is a very large one, and ornamented with about half a
dozen costee, while the other is only striated with numerous rays ; and the ears of the left
valve are both striated ; angle of divergence, 90°. The nearest approach to this species is P.
Thorenti, D’Archiac, Tr. Geol. Soc. Fr., 2d sér., t. xi, pt. 1, p. 211, pl. 8, figs. 8, 8, a, 8,
which much resembles it in the ornament, but the auricle of that shell is so much
smaller that I must presume the two to be different. The figure there taken was from a
solitary specimen, and the auricle, if natural, does not appear to me to be perfect.

2. Pecren carinatus, J. Sowerby. Tab. IX, fig. 5, a, 6.

PECTEN CARINATUS. J. Sowerby. Min. Conch., t. 575, 1828.
— — Prestwich. Journ. Geol. Soc., 1847, p. 405.
— — Morris. Cat. Brit. Foss., p. 178, 1854.

Spec. Char. P. testé orbiculari, lenticulari, equivalvi, equilateral, costaté ; costis
(circa 20) subequalibus, rotundatis, in medio carinatis; interstitiis levibus ; auriculis
subequalibus.

Shell orbicular, lenticular, equivalved, equilateral, costated; ribs about 20, nearly
equal, rounded, with a sharp keel along the centre of each; interspaces generally naked,
or only marked with fine lines of growth; auricles nearly equal.

Diameter, \ inch.

Locality.—Barton.

ell TU

BIVALVIA. 39

I have seen this from one locality only. The solitary line spoken of by Mr.
Sowerby, in ‘ Min. Conch.,’ as generally running down the centre of the interspaces, is a
character not constant; in some it is not visible, while in others this space is occupied
with several lines. The spaces between the ribs are not quite so wide as the ribs
themselves, and these show fine curving and radiating striz. The keel in some
individuals is large and strong, giving an almost angular form to the rib; but in
general this keel is merely a sharp line upon the otherwise rounded coste, closely ap-
proaching P. reconditus. The auricle on the pedal side is slightly the larger of the two,
and in the right valve this auricle is costated and sinuated beneath, with three or four
denticulations upon the margin of the shell.

3. Pecten corneus, J. Sowerby. Tab. IX, fig. 7, a—d.

PECTEN coRNEUsS. J. Sow. Min. Conch., t. 204, 1818.
— — Id. in Dixon’s Geol. of Sussex, t. 4, fig. 6, 1850.
— _— Nyst. Coq. Foss. Belg., p. 299, pl. 23, fig. 1 a, 6, 1843.
—- — Morris. Cat. Brit. Foss., p. 178, 1854.

Spec. Char. BP. testé tenuissimd, orbiculato-depressé vel plano-lenticulata, equilaterali,
levigatd, vel obsoleté striatd ; striis irregularibus ; umbonibus acutis ; auriculis subequa-
bus, rectangulis, superné prominentibus, tenuissimé striolatis.

Shell very thin, orbicular, depressed, or of a flattened lenticular form ; smooth, or with
fine, nearly obsolete striae; beaks sharp; auricles nearly equal, rectangular; generally
with fine radiating strize.

Diameter, 22 inches.

Localities, Bracklesham, Bramshaw, Brook, Stubbington (Zdwards), Cuffell (Prest-
wich); var. corneolus, Highgate (Wetherell).

Belg., Les sables de Lacken, Jette, Forét, St. Gilles (WVysf).

This species is abundant at Bracklesham, but, on account of its extreme tenuity, is not
very common in cabinets. Our shell, which is smooth to the naked eye, exhibits under a
common hand-glass fine diverging strize, most distinct near the margins of the shell, and in
well-preserved specimens they are plainly visible all over; it is also rayed irregularly on
the inside, ‘The auricles are plain and smooth, except under a magnifier, when the same
kind of fine radiating strize may be seen as are upon the shell. ‘here are at the
base of the auricles, on the interior, two prominent diverging teeth, those im the right
valve being higher and smaller than in the other, and the adductor muscle-mark is very
conspicuous, generally of a darker colour; this is large and rounded, and in the right
valve, which is the deeper or more convex one, it is higher in the shell or nearer to the
hinge than in the left or flatter valve, where it is more in the centre, giving a more
powerful action to that valve, and the mark of the mantle is visibly impressed upon the
interior. The shell is nearly orbicular, but sometimes the diameter is greater longi-

40 EOCENE MOLLUSCA.

tudinally, sometimes the reverse ; the ears are slightly unequal, the pedal one being a
trifle the larger. The shell diverges from the umbo at an angle of about 120°, and
the divergence of the lines upon the fainter portion of the shell at about 80°.

The typical specimens of this species are from Selsey, Bracklesham, and Stubbington,
where they attain to full proportions. There are also specimens found in the London
clay at Hampstead, assigned to this species ; these are seldom more than half the diameter
of the Sussex shell, and may be considered as a variety, which I will call corncolus, Pl. IX,
fig. 7, d. The difference in magnitude would not of itself be sufficient to entitle these shells
to the position of a variety ;' but there is a slight variation in the right auricle, which is
rather more rounded, and in some of the specimens the proportions are different, giving
them a more ovate form.?

4. Pecten contuBERNALIS, S. Wood. Tab. IX, fig. 8.

Spec.Char. P. testa tenui, subcorned, orbiculato-depressd, aquilaterali, tenuissime striata,
strus radiatis argutis ; umbonibus acutis; auriculis subequalibus, superné rectangulis,
costellatis.

Shell thin, subcorneous, orbicularly depressed, equilateral, and very finely striated,
strie thin and radiating, beaks acute ; auricles nearly equal, and prominently radiated or
costated.

Diameter, 14th inch.

Locality. Herne Bay (Hdwards).

This shell appears to present differences sufficient to entitle it to an isolated position :
the elevated radiations or costz upon the auricles will distinguish it ; and the whole surface
is more strongly marked by the fine, divaricating, and curving strize with which it is
covered, and these extend over the auricles. I have seen but one specimen, which is in
Mr. Edwards’ cabinet, but this differs so materially that I think it cannot belong to the
preceding species. The auricles are comparatively much larger than those of corneus :
in that shell their length does not exceed ;ths of the diameter of the valves, while in
this species they are $ths; and although the young shells of Pecten have generally larger
ears, comparatively, than when full grown, a great difference may be seen in specimens of
the two species of corresponding size.

1 Since writing the above, I have seen a specimen of this variety in Mr. Wetherell’s cabinet, which
measures 14 inch in diameter.

2 At p. 72, t. 11, ‘Anim. s. Vert. du Bassin de Par.,’ M. Deshayes has pointed out the confusion that
exists among species with the above name, and enumerates not less than seven, but which he considers to be
quite distinct. One of these seven (P. corneus, Melville, pl. 111, figs. 11, 12,) very strongly resembles the
young state of our shell, corresponding with the Highgate variety (corneolus).

BIVALVIA. 4]

5. Pecrren pupiicatus, J. Sowerby. ‘Tab. VIII, fig. 10, a—c; and Tab. X, fig. 3.

PecTEN DuUPLICATUS. J. Sow. Min. Conch., t. 575, 1828.
— — Morris. Cat. Brit. Foss., p. 174, 1854.

Spec. Char. LP. testa orbiculari, depressd, radiata ; valvd dextrad sublevigald ; alterd
costellatd ; costellis numerosis, imbricatis ; auriculis subequalibus.

Shell orbicular, depressed, radiated ; one valve nearly smooth or with obsolete coste,
the other with thin rounded ribs, 14 to 16, imbricated, increasing with age by the interpo-
sition of an additional rib ; auricles nearly equal.

Diameter, 14 inch.

Localities. Highgate, Primrose Hill (Wetherell), a, 6, f, Waverstock Hill, c, Muswell
Hill (Zdwards).

A strongly marked and ornamental species, and in the living condition probably a
handsome shell. The specimens in cabinets are by no means abundant, and rarely in good
condition. Mr. Sowerby, in ‘Min. Conch.,’ represents one of his valves as quite smooth.
In all Mr. Edwards’s specimens, the right valve has more or less depressed or obsolete cost,
and as many as thirty of these faint rays may be counted, and these are distinctly visible in
the interior. The left valve is ornamented with about sixteen thin, rounded, and imbricated
rays on the younger shell ; these are doubled, and again doubled, as the shell increases in
size, by the interposition of a rib ; they are all closely and regularly imbricated, but not the
interspaces.

6. Pecren 1ponrvs, 8. Wood. Tab. VIII, fig. 9, a, 6.

Spec. Char. BP. testé inequivalvi? suborbiculari, subdepressa, equilaterali, costatd, et
concentricé squamulatd ; costis 18-15 elevatis, magnis, subquadripartitis ; auriculis, equali-
bus radiantibus.

Shell inequivalve? suborbicular, somewhat depressed, equilateral, costated, and
concentrically striated; ribs 13-15, elevated, large, and ridged; auricles equal and
radiated.

Diameter, 1} inch.

Localities. Hill Head, Stubbington (Zisher), Brook near Lyndhurst (Zdwards).

This is an ornamental shell, and appears quite distinct. It was first discovered by
the Rev. Osmond Fisher, who has obtained about a dozen specimens from the first locality,
and Mr. Edwards has very recently added three to his cabinet from the latter.

In well-preserved specimens, the ribs are ornamented with one elevated and two lateral
ridges, dividing the surface of the rib into four portions; the interspaces are about as broad
as the ribs themselves, in which a ray or two may occasionally be seen on the outer or
older portion of the shell; the surface, when perfect, is ornamented with regularly concen-

6

42 EOCENE MOLLUSCA.

-_

tric striae or small imbrications. The auricles are nearly equal, and they are ornamented
with eight or ten moderately sized rays.

7. Pecren Prestwicuil, Morris. Tab. VIII, fig. 7, a, 6.

PecTeNn Prestwicuil. Morris. Geol. Journ., vol. viii, p. 266, t. 16, fig. 8 a, 6, 1852.
— — Id. Cat. Brit. Foss., p. 178, 1854.
— — Desh. An. sans Vert. du Bas. de Par., p. 75, pl. 79, figs. 4—6.
— BReEviAurItus? Id. - - - - p. 74, . 1—3.

Spec. Char. “P. testa tenui, compressa, radiatim obsolete costatd, costis subsquamosis,
nterstitiis oblique irregulariter striatis ; auriculis inequalibus, radiatis.”

“ Shell thin, compressed ; margin orbicular, with a rectangular beak ; radiated with very
slightly raised ribs, distinctly imbricated, the intervening furrows twice as large as the
vibs ; irregularly and obliquely striated ; ears unequal, with three or four radiated coste.”

Diameter, 1 inch.

Localities. Richborough Castle (Prestwich), Herne Bay (Bowerbank).

This species possesses about sixty small ribs or rays, very slightly elevated, and the
surface is covered with diverging or divaricating and curved striz; these are most conspi-
cuous as they approach the pedi- and siphoni-lateral margins; the auricles are compara-
tively large, unequal in size, with a small sinus at the base of the right one; these
auricles are covered with about five or six rays. The diverging striz appear to cover
our shell, passing over the riblets, as well as between them; and there appears to be
a Jarge muscle-emark under the pedal auricle. I have seen only two specimens.

The British fossil corresponds so closely with the older species, P. dreviauritus, that,
judging alone from figure and description, I am unable to detect. any difference which can
fairly be called specific; and unless there be greater distinction shown between specimens
when compared, the name of our species will have to be changed. In the figure given in
the ‘Geol. Journ.,’ above referred to, the artist has reversed the auricles.

8. Prcten reconpitus, Solander. Tab. IX, fig. 3, a—d.

OstrEA RECONDITA. Solander. Brand. Foss. Hant., p. 42, pl. 8, fig. 107, 1766.
PrctEn RreconpItTuS. Myst. Coq. Foss. Belg., p. 302, pl. 25, fig. 2 a, 6, 1843.
= — J. Sow. in Dixon’s Geol. of Suss., t. 3, fig. 27, 1850. non. Sow. Min.
Conch., t. 575, figs. 5, 6.
— — Lyell. Belg. Tert., loc. cit. ant. p. 353, 1852.
+= — Morris. Cat. Brit. Foss., p. 179, 1854.
_ PLEBEIUS. Tennant. Strat. List. Brit. Foss., p. 31, 1847.

BIVALVIA. 43

Spec. Char. P. testé equivalvi, orbiculari vel subovatd, costatd, costis 18-24
conveais, levigatis ; sulcis equalibus, aliquando squamulosis ; auriculis inequalibus.

Shell equivalve, orbicular, sometimes sub-ovate costated; ribs 18-24, convex and
smooth ; interspaces about equal in breadth to the ribs, and occasionally sub-squamulose or
imbricated ; auricles unequal.

Diameter, 1+ inch.

Localities. Barton.

Belgium (JVys?).

The prevailing Pecten at Barton possesses the above characters, and it may be con-
sidered the representative of the genus in that deposit, as the 30-radiatus is at Brackle-
sham; and although perhaps this is not quite so variable as the Bracklesham shell, I have
found it exceedingly difficult to fix the species.

The generality of our specimens are nearly circular ; sometimes the diameter from thie
umbo to the ventral margin is greater than in the opposite direction, but not often so.
Brander’s figure is a deviation in excess. I have been unable to find the type specimen
from which his figure was taken, but, from the general accuracy of his other species, it was
most probably a faithful representation, and in my own cabinet is a specimen somewhat
approaching that form; so that the above name is considered to be applicable to this
common Barton shell.

Specimens have in general from 18 to 24 ribs, and the spaces between them equally
divide the surface of the shell; the ribs are generally smooth, and so are sometimes the
interspaces, but they occasionally show numerous and close imbrications, and the surface
is covered with fine curved and diverging strize, most conspicuous between the ribs.

The auricles are unequal in size; the one on the pedal side of the right valve is large,
and has six or seven scaly rays, the upper, as usual, larger and more distant, and at the
base of this is a considerable sinus for the byssus, with ridges er denticles on the body of
the shell, varying from four to ten; the other auricle is also rayed. The muscle-marks are
not immediately or strictly in opposition ; they are situated higher up or nearer the hinge
in the right valve, and lower down or more in the centre in the left, but it is so with
several species in this genus."

1 Some species exhibit more than ordinary variation in individuals, diverging in form far beyond what is
shown in any proximate species ; others, living under the same (apparently) adverse circumstances, are not
affected in a similar manner, but preserve a uniformity of character without any deviation, showing an inapti-
tude to change under similar conditions. Where bivalve shells have displayed the greatest aberration from
what is presumed to be the normal form or typical outline, the change seems to me rather to have been
more towards a concentration, as it were, so that a variety of a bivalve, whose typical form would have
proportions of length greater than height, would be most shown in a deviation from that type, by a
reduction of length with a tendency to the orbicular. An orbicular shell in its deviations would, on the
contrary, be rather in the direction of an enlargement or extension in its height. I might mention two
or three Crag forms that strongly exhibit this tendency, viz., Venus casina, Cardita senilis, and Mya
truncata ; but this variation seems to be from a failure of vigour, as the abnormal form is generally

rare.

44 EOCENE MOLLUSCA.

M. Deshayes, in speaking of the Paris Basin shell, P. plebeius, says it is variable, with
20 to 28 ribs, and he makes two varieties." M. Nyst says of P. reconditus, from Belgium,
that he has seen but one valve, and this, judging from his figure, does not differ from our
shell. The specimens from Bracklesham, (as I have elsewhere said), figured by My. Sowerby,
and assigned with doubt to plebeius, most probably belong to 30-radiatus.

There appears to be less variation of form in those bivalve shells whose outline is
circular or lenticular than there is in those whose normal condition is more elongated.
Pectens are, in general, I think, uniform im outline ; and when a specimen like the one
figured by Brander presents so great a difference, there is more reason to consider it as
belonging to a distinct species, than as a variety of one that is orbicular; and it was only
after long and careful examination that I could, on that supposition, bring myself to believe
it to be only a variety. Brander’s figure may, however, be the representation of a distinct
species ; if so, I have not seen it.

9. Pecrrn savamuLA, Lamarck. ‘Tab. IX, fig. 6.

PECTEN SQUAMULA. Lam. Ann. du Mus., t. vili, p. 354, No. 3, 1806.
— — Id. Hist. des An. s. Vert., t. vi, p. 183, No. 27.
— — Desh. Coq. Foss. des Envy. de Par., t. i, p. 304, pl. 45, figs. 16—18.
— — Id. An. sans Vert. du Bassin de Par., t. ii, p. 74, 1860.
— — Id., 2d edit. Lamk., t. vii, p. 164, No. 34, 1836.
_ — D Orbigny. Prod. de Paleont., t. ii, p. 326, No. 528, 1850.
— — J. Sow. in Dixon’s Geol. of Sussex, pp. 94, 172, pl. 3, fig. 29, 1850.
= = Morris. Cat. Brit. Foss., p. 179, 1854.
— squamuLosus. Desh. Ency. Meth. Vers., t. iii, p. 717, No. 7, 1832.

Spec. Char. P. testé minimé, rotundatd, depressd, equilateral, equivalvi ; extus
lavissimd, intus octo ad decem costaté ; auriculis magnis, subequalibus.

Shell minute, rounded, depressed, equilateral, equivalve ; very smooth externally, inside
with eight to ten cost ; ears large, slightly unequal.

Diameter, th of an inch.

Localities —Bracklesham, Bramshaw (dwards).

France, Chaumont et Laon (Des/.)

This is exceedingly rare; I have seen it only in Mr. Edwards’s cabinet. It is a

miniature representation of P. plewronectes, and, like that species, is externally smooth, and

1 The shell from the Paris Basin appears to differ from our species. In some specimens of pledeius, in
Mr. Edwards’s cabinet, sent to him by M. Deshayes, the rays are smooth at the top, rounded and imbri-
cated at the sides, and I cannot see the fine curving and diverging strize between the ribs which are so
distinct in P. reconditus.

BIVALVIA. 45

has its rays or costa upon the inner surface: the exterior seems to have been glossy, and
the left valve was probably ornamented with colour in zigzag, somewhat like P. similis ; the
shell is extremely thin, and the internal costz can be distinctly seen on the outside. The
auricles are large, as is usually the case in minute species of this genus, and the one on
the pedal side is the larger of the two; this in the right valve is rounded at the angles, and
ornamented with about half a dozen elevated and imbricated rays, and sinuated near its
junction with the shell. In the left valve, the auricle on the pedal side is also larger, but
it is neither rounded at its upper angles, nor sinuated beneath. It is most probably
identical with the Paris Basin shell, and is not very distantly related to another small
fossil species, P. sgwama, Scac. (P. pygmaeus, Miinst.), but this is said to be furnished with
as many as twenty rays on the inside of the valves. The figure with this name in ‘ Goldf.
Pet. Germ.,’ pl. 99, fig. 6 a, 4, appears a larger shell ; but it has the same number of internal
ribs, and corresponds in other respects. Nilsson, ‘ Petrificana Suecana,’ p. 24, t. ix, fig. 18
AB, describes a species, P. imversus, which is intermediate in size between sgvamula,
Goldf., and pygmeus, Mist.

Pecten squamula (Geinitz ‘Charak. der Schicht und Petr. des Sich. Bohm Kreid,’ p. 83,
taf. xxi, fig. 8) is altogether a different species.

10. Pecten 30-rapratus, J. Sowerby. Tab. IXsfig. 4, a—A, and Tab. VIII, fig. 8.

Prcten 30-rapiatus. J. Sow. in Dixon’s Geol. of Suss., p. 172, t. 3, figs. 30, 31, 1850.
— 40-rapiatus. Id. - - . py 173; figs so.
— _ PLEBEIUS. Td. = - 2 a 172,-figs. 28; 32.
—_— MULTISTRIATUS? Morris. Cat. Brit. Foss., p. 178, 1854.

Spec. Char. P. testa variabilis, equivalvi, orbiculari, radiatim costatd, costis numerosis,
rotundis vel angulato-sulcatis ; interstitiis interdum squamulis, minimis, asperatis ; quan-
doque radiatis ; auriculis inequalibus.

Shell variable, equivalve, orbicular, with numerous ribs, rounded or subangulated ;
interspaces sometimes with small, rough scales or lines of growth, sometimes with an inter-
mediate ray ; auricles unequal.

Diameter, 13ths inch.

Localities. Bracklesham, Bramshaw (dwards).

The deposit at Bracklesham Bay has yielded an abundance of specimens belonging to
the genus Pecten, and these present an unusual amount of variation, rendering a specific
determination a task of extreme difficulty. Mr. Edwards had previously examined his
specimens ; the accompanying notes were in his cabinet, and I have his permission to
transcribe them :

46 EOCENE MOLLUSCA.

“(a) Coste 24, 25, round, finely imbricated with intermediate costellz, imbrications
continued over the interstices. Interstices deep; shell sub-
orbicular.

(6) Costa 24—28, round, imbricated; imbrications more distant than in a;
interstices shallow; costellze occasional; shell tranversely sub-
orbicular.

(c) Coste 18—32, round, finely imbricated; costellz occasional; shell nearly
orbicular.

(d) Costee acute,

(e) Multistriatus P

(/) ‘Tripartitus ?

(g) Transversely sub-orbicular, costa 30, coarsely imbricated.

(2) Coste round, smooth.” (dwards.)

My own observations pretty nearly coincide with the above, and my formula will

stand thus:

a. Ribs 25-—82, rounded and smooth, without an intermediate ray. The smooth-

ness may possibly be from attrition or decortication.

6. Ribs 24—82, rounded and imbricated, without intermediate ray.

C6 gg.—«S DD —28 with a »

39 29

d. _,, 24-28 tripartite, imbricated all over, without intermediate ray.

e. 4, 24-—28 mA os with a Es
J» +26—28 acute, subcarinate, and slightly imbricate, without intermediate
ray.

Although we have both attempted the above divisions, I fear the lines of separation
will be anything but distinct between these variations.

One perfect specimen, with the two valves united, shows the ribs quite smooth and
rounded; another, equally perfect, has the younger portion of the shell with smooth ribs,
while the outer and older portion is strongly imbricated both over the ribs and between them ;
and on another specimen the younger portion is imbricated, and the older portion smooth,
uniting thus in one individual the characters of what are called varieties. Where the
intermediate ray is developed, it is generally most prominent at the margins. I believe the
figures of Mr. Sowerby, above referred to, are representations only of varieties of this
variable species. The 40-radiatus I imagine to be one of the lesser number of ribs, with
the intermediate ray elevated into a primary one. The diameter of the shell is generally
a trifle in excess, measuring from the pedilateral to the siphonilateral margin ; but in some
specimens the proportions are decidedly reversed. The auricles are rather large and

BIVALVIA. 47

unequal, and are ornamented with about half a dozen (5-7) primary rays, generally imbri-
cated; the two upper often coalesce, particularly in the right valve, beneath which there
is a deep sinus.

P. opercularis is mentioned in Mr. Prestwich’s list of species, in his paper on the
London clay (p. 405, Geol. Journ.), as from Bracklesham. This may perhaps have been
a dead specimen of the recent shell, or perhaps a specimen from the newer Tertiaries of
that locality ; or it may have been a variety of 30-radiatus. I have seen nothing from the
older Tertiaries that can be united with the recent species, opercularis.

Pecten subreconditus, D’Orb. (Prod, Pal., 1850, p. 393, No. 1106), is, I think, not an
Eocene shell. He refers to ‘ Sow. Min. Conch.,’ pl. 575, figs. 5, 6, which are representations
of a Crag specimen of opercularis. P. subreconditus, Pictet (pl. 88, fig. 10), who refers to
D’Orbigny, is probably the same.

LIMA, Brugueére, 1792.

Generic Character. Shell ovate, equivalve, generally inequilateral ; the pedal region
oblique and gapmg. Sometimes the shell is straight and equilateral; exterior occasionally
smooth, more often radiately ribbed or striated, rough or squamous. Hinge area triangular,
extended into auricles ; connexus bipartite, with central pit; adductor impression large,
lateral, and double ; two small pedal scars.

Animal has the mantle margins disunited, and fringed with a double row of tentacular
filaments, the inner one long and pendulous ; ocelli inconspicuous ; foot small, finger-like,
furnished with a byssal groove.

Several divisions have been made of the shells that will come into the above
formula.

Limea has been proposed for those species which have a row of teeth or crenulations
upon the hinge margin, and Zimatula for those which are equilateral and closed.

In general, the oblique species (Zzma proper) have one side straight, and the other
rounded, with one opening ; but this is by no means constant, as there is often a large gape
on both sides. The shell of Zcmatu/a has sometimes a row of crenulations, while the same
form of shell is known to be without them. Zimea' has teeth on each side of the cartilage-
pit upon the hinge-margin ; these are sometimes in a rectangular position, at others they are
placed obliquely to the hinge-line, and these are generally upon shells that are equilateral
or nearly so, but they are not confined to that form of shell ; and in the oblique species there

1 Goldfuss has figured two species of Secondary fossils, one from the Lias, LZ. acuticosta, pl. 107,
fig. 8, with large dentations.

48 EOCENE MOLLUSCA.

is often a large distinct tooth in one valve, that mterlocks into a depression in the other.
M. Loven, in speaking of the amimal of Limea Sarsii, says that the margin of the mantle
is destitute of those tentacular filaments which form so rich an ornament to the animal of
Lima hians.

In the fossil genus Plagiostoma, there is a large gape on the rounded or siphonal
region ; but this distinction is by no means a generic one, as the same character may be seen
in shells of the living species of Zama proper. -

Some of the animals of this genus spin a byssus, and are said to be fixed; but others
are able to swim with considerable vigour, like the Pectews, by openimg and rapidly
closing or flapping their valves. The animal of Lima scans is a most beautiful object,
sometimes of a deep crimson colour, with an orange-coloured mantle ; and it makes an
artificial burrow with fragments.of coral, shells, amd sand. The reeent-shell of this genus
is always white, and, according to Dr. Carpenter, its outer layer consists of coarsely plicated,
membranous lamellz ; the inner is perforated by minute tubuli, forming-a complete network.

This is wholly a marine genus, and the species are found in various parts of the world,
from Norway to India, Australia, and the West Indies, and they present no special
indication of climate. Mr. McAndrew obtained the largest living species, measuring 53
inches in height and 44 long (eacavata, Chemn.), on the coast of Finmark, and the European
species possess a vertical range from 1 te 30 fathoms. -A Permian fossil strongly
resembles this genus, and it has. continued through all the Secondary periods in large
numbers ; the Tertiaries are somewhat scantily supplied. - -

1. Lima compta, S. Wood. Tab. XI, fig. 5.

Spec. Char. L. testa tenui obovatd, valde obliqud, subdepressd, inequilaterali ; striata
vel costulata, striis vel costulis numerosis, angustis, regularibus, acutis, scabris; auriculis
magnis equalibus ; cardine angusto, recto, simplica ; umbonibus acutis, subpromenentibus.

Shell thin, obovate, very oblique, somewhat depressed, inequilateral, striated or
costulated, striae or riblets numerous, narrow, sharp, regular, and rough ; auricles large
and equal; hinge-line straight, with pointed and, rather prominent beaks.

Longest diameter, % of an inch.

Locality. Barton (Hdwards).

One specimen is all that I have seen, and: this is not quite perfect; but it differs
from any species I am acquainted with, as indicated by the lines of growth. I believe it to
be distinct. The entire surface of this shell is covered with radiating striz, and these are
numerous and regular. It somewhat resembles Z. tenwis, Desh. (An. sans Vert. du
Bassin de Par., t. 11, p. 67, pl. Ixxviu, figs. 20—22); but it is more oblique than that
figure, having the umbo incurved, and not so prominent ; there is also, seemingly, a deeper
sinuation under the auricle in the siphonilateral margin, and the rays upon our shell are
more numerous and less regular.

BIVALVIA. 49

2. Lima Expansa, J, Sowerby. ‘Tab. XI, fig. 6.

Lima Expansa. J. Sow. in Dixon’s Geol. of Sussex, pp. 94, 172, t. 3, fig. 34, 1850.
— — Morris. Cat. Brit. Fossils, p. 172, 1854.

Spee. Char. LL. testa parva, oblique orbiculari, subtransversd, tenui, fragili, subequi-
latcrali, depressiusculd ; extis strits radiantibus ornatis, interstiliis punctatis ; cardine brevi,
auriculis minimis, subequalrbus.

Shell small, obliquely orbicular, slightly transverse, thin, fragile, and subequilateral ;
externally ornamented with about 40 rays, interstices punctated ; hinge short, with small,
nearly equal auricles.

Diameter, + of an inch.

Locality. Bracklesham (Hdwards).

“Much more orbicular than any other Zima I know, but much too oblique for a Pecten.
It is extremely rare. Mr. Edwards has one nearly perfect valve, and Mr. Dixon a fragment.”
(Sowerby.)

This small shell somewhat resembles in outline Z. dilatata, Desh. Coq. foss. de Par.,
p- 298, pl. xliii, figs. 15—17. Our shell has about 40—42 rays, which are broad and flat, the
interspaces narrow, and prettily ornamented with transverse projecting ridges, between which
are rounded and deep punctations. The hinge-area in Mr. Edwards’ specimen is broken
and not very distinct; it was probably small, with small auricles.

3. Lima soror, S. Wood. ‘ab. XI, fig. 7, a, 6.
Lima oBiiaua. Morris. Catal. Brit. Foss., p. 172, 1854.

Spec. Char. L. testé ovato-clongatd, obliqud, inequilaterali, tenut, striata, pedi-regione
levigata ; strvis angulatis, irregularibus ; umbonibus parvis, acutis; auriculis minimis,
brevibus, equalibus.

Shell ovately elongate, oblique, inequilateral, thin, striated, with small angular and
irregular ribs or riblets ; beaks small and pointed, auricles short and equal.

Longest diameter, ths of an inch.

Locality. Wighchiff, Barton (Ldwards).

There are two specimens of this species in Mr. Edwards’ cabinet, and they are in a
sufficiently perfect condition to show a considerable, and what I presume is a specific,

difference from Z. obliqua of Deshayes, if I may judge from figures and descriptions of
that shell.

50 EOCENE MOLLUSCA.

In the 2d ed. of Lamarck, tom. viii, p. 120, the author says, “toute sa surface est
couverte de striz longitudinales.”

In the present species, the pedal region, from the margin to the elevated ridge or most
tumid portion of the shell, is quite free from strize of any kind ; and on the centre the strize
are small, close, and numerous, becoming larger and wider as they diverge from the middle
towards both regions; the hinge-line is short, and there is a small gape or sinuation in the
siphonilateral margin immediately under the auricle ; the umbo is small, sharp pointed,
but not very prominent, unlike that represented in the French shell, which has also appa-
rently agreater height. With these differences, I have ventured to propose for the English
fossil a new name.

SPONDYLUS. JLzmn., 1767.

Sponpyuus. Rondelet, 1555. List., 1686.
Sponpyuitgs (sp.). Aldrov., 1648.

ARGUS ET ARGODERMA (sp.). Poli, 1795.
Puacrostoma (sp.). Lamk., 1819.
Diancuora. J. Sowerby, 1814.

Poporsts. Lamk., 1819.

Pacuytos. Defrance, 1825.

Pacuyta. Menke, 1830, fide Herrm.
Pacuytus. Agass., 1847.

Generic Character. Shell irregular, generally thick and strong, and attached by the
right valve ; ribbed or costated radiately ; more or less spiny or foliaceous ; eared ; umbones
often remote ; lower or attached valve with a triangular hinge-area ; connexus bipartite,
cartilageous portion between two curved interlocking teeth in each valve; impression by
the adductor double.

Animal with the edges of the mantle disconnected as in Pecten, and furnished with
two rows of tentacular filaments ; foot small, cylindrical, truncated.

The species of this genus in the recent state are about thirty, and these are distributed
over the glebe, but mostly in tropical or subtropical regions ; many of these are beautifully
coloured, and highly ornamented with spines or broad foliaceous projections ; these
appendages are sometimes long and pointed, while at others they are merely rudimentary
spines. These shells are known by the name of spiny oysters, but they are wholly
distinct from the genus Osfrea, and approach nearer to Pecten, which they resemble
in some characters. The hinge-area is furnished with prominent denticles, two in
each valve; those in the lower are small, and situated close to the cartilage; the two
teeth of the upper valve are more remote, and lock into depressions outside the smaller
teeth of the lower valve. The connexus is more or less internal, opening the shell by

— ———— << = —

BIVALVIA. 5)

—

expansion ; but in many it is bipartite, extending outwardly in a furrow, like the oyster; a
small ligament sometimes occupies the hinge-margin, and this margin is occasionally rugose
or faintly denticulated. ‘The lower valve is generally the most spiny, and in the recent
state is nearly colourless ; this is the right valve, and the one by which it is most frequently
attached. Many fossil species are known, commencing low in the Secondary series. The
structure of the shell in some of the species has long been noticed as being composed of
two different layers (and in the recent shells of two different colours), the inner being very
distinct from the outer, and very destructible.

This genus in the fossil state is supposed to indicate, for the formation in which it is
found, somewhat of a tropical character; it may be so as a general rule, but three species
are found at the present day, in the Mediterranean, in association with northern forms.
It is purely a marine genus, and the living species are generally found in deep water.

SPONDYLUs RARISPINA, Deshayes. ‘Tab. VIII, fig. 1, a, 6.

SPonDYLUS RARISPINA. Desh. Coq. Foss. des Envy. de Par., p. 321, pl. 46, figs. 6—10.

— — Id. An. sans Vert. du Bassin. de Par., t. ii, p. 90, 1860.

a= — Nyst. Coq. Foss. Belg., p. 308, pl. 25, fig. 4 6, 1843.

— — D' Orbigny. Prod. de Paléont., t. ii, p. 393, No. 1116, 1850.

a — Morris. Cat. Brit. Foss., p. 182, 1854.

— —— Pratt. Proc. Geol. Soc., vol. iv, p. 158, 1843.

— --— D’ Archiac. Tr. Geol. Soc. Fr., 2d ser., t. iii, pt. il, p. 437, 1850.

— — J. Sow. in Dixon’s Geol. of Suss., p. 173, 1850.

_ — Bellardi. Mém. de la Soc. Géol. de Fr., 2d ser., t. ili, p. 260,
1852.

— — Id, Catal. ragionato dei foss. Numm. d’Egitto, p. 26, Ne. 66,
1854.

Spec. Char. Sp. testd ovato-rotundatd, obliqud, brevi-aurita ; sulcis vel costis radian-
libus, numerosis ; majoribus spinis, raris, echinatis, alteris subequalibus muticis.

Shell roundly ovate, oblique, with small auricles, covered with numerous radiating
strize or riblets, the larger having distant spines or imbrications.

Longest diameter, 13 inch.

Localities. Bracklesham (Ldwards and Dizon).

Belgium, les sables d’Uccle, de St. Gilles, et de Dieghem (JVys?).
France, a Chaumont (Deshayes), Biaritz (D’ Arch.), Nizza (Bellardi).

I have seen only two specimens of this species, and those are both of the left or free
valve. Both these specimens are alike oblique in form; the larger rays are sparingly
covered with small spines or imbrications, and between these are three, sometimes two,
intermediate rays, which are generally smooth. ‘This valve is much depressed ; the right
or adherent one was probably tumid. The hinge is strong, and in this valve there are

o2 EOCENE MOLLUSCA.

deep and large depressions for the reception of the teeth of the opposite one. Auricles
small. The muscle-mark is large, rounded, and eccentric. This species strongly resembles
Sp. Cisalpinus, Brongniart, and may probably (as suggested by M. Deshayes) be ouly a
strongly marked variety of that shell.

AVICULA. Klein, 1753.

Gen. Char. Shell inequivalve, inequilateral, obliquely oval; left valve the larger
or more tunid, right valve with a byssal sinus; cartilage-pit oblique; hinge sometimes
edentulous, at others with one or two small cardinal teeth, and an elongated lateral
one; hinge-line rectilinear, with the extremity generally prolonged; muscular im-
pressions large, subcentral; pedal scar high in the umbonal region; impression of the
mantle entire ; connexus ligamentous.

Animal obliquely triangular; the edges of the mantle disunited, except at one point
where the juncture separates the incoming from the outgoing canals; margins fringed, and
furnished with a pendant curtain ; foot small, subcylindrical, or digitiform, grooved ; byssus
sometimes solid, with an expanded termination.

There is much difficulty in assigning a proper limit to this genus, which has so many
nearrelations. Conchologists are greatly at variance as to what should be included within
its generic boundaries. ‘The hammer oyster (JZa//eus), a recent shell, with an extension of
the hinge-margin on each side of the umbo, has been considered as not entitled to generic
distinction ; the young shell being extended only on one side, and it is then very like a
true Avicula. 'Vhere are also some fossils of the older rocks which bear a very strong
resemblance ; these have been elevated into genera, under the names of Pfer/nea, Ptero-
nites, Pteroperna, Ambonychia, &c., each presenting some small distinctive character.
The claim of A/eleagrina to isolation appears to rest upon a less extended hinge-margin, than
that which, in the type of this genus (Mytilus hirundo), gives such a winged-like form to that
shell ; this appendage is exceedingly variable in different species, and indeed is of different
lengths in the individuals of the same species, the young differmg from the parent shell ;
while also among the full-grown specimens, this character is by no means permanent in
the same species. ‘lhe form of the shell, divested of its extended hinge-line, bears a strong
resemblance to that of Mytilus.

The connexus in this genus is in general simple, and spread over a large external area.

Twelve or thirteen species have been described from the French Eocene deposits, and
a few from the more recent formations.

The only species of this genus now found on our own coasts and in the Mediterranean
ranges, in the latter sea, according to Mr. M‘Andrew, from eight to thirty-five fathoms.

BIVALVIA. a3

1]. Avicuna arcuata, J. Sowerby. Tab. XI, fig. 3.

AvicuLa arcuata. J. Sowerby. Geol. Trans., 2d ser., vol. v, t. 8, fig. 15, 1834.
— — Morris. Cat. Brit. Foss., p. 163, 1854.

Spec. Char. Av. testd elongald, obliqud, arcuatd, compressa, laevigata, tenui ; valde
inequilaterali.

Shell elongate, oblique, and curved, compressed, smooth, thin; very inequilateral.

Longest diameter, ths of an inch.

Locality. Wampstead, ( Vetherell).

All that I have seen is the unique specimen in Mr. Wetherell’s cabinet. It appears
to be distinguished by its curved form. 4. microptera, Desh. (p. 290, pl. 43, figs. 18—
20), resembles it in some characters, but is not so much curved.

2. AvicunA MEDIA, J. Sowerby. Tab. XI, fig. 1, a—d.

AvVICULA MEDIA. Jd. Sow. Min. Conch., t. 2.
— — Prestwich. Geol. Journ., 1847, p. 401.
-- -- Morris. Cat. Brit. Foss., p. 163, 1854.
~- — Wetherell, Phil. Mag., p. 464, 1836.
— — D Orb. Prod. de Paleont., t. ii, p. 391, 1850.

Spec. Char. Av. testé inequivalvi, ovato-trigond, valdé obliqua, levigata, fragili ;
valvd sinistrd conveed, tumidd; valvd dextrd depressiore; umbonibus prominentibus,
remotis ; area cardinali magno.

Shell inequivalve, ovately trigonal, very oblique, smooth, and fragile, nacreous ; left
valve convex and tumid; right valve more depressed; umbo prominent, with a large and
broad cardinal area.

Diameter, length 2 inches, height 13 inch.

Localities. a, 6, d, Brockenhurst. c, Barton, Bracklesham, Hampstead (Edwards).
Highgate, Chalk Farm, Potter’s Bar (Wetherell). Sheppey, Basingstoke, Newnham
(Prestwich).

This is by no means rare, and the specimens present a large amount of variation.
In some individuals, the length of the hinge-line extends so far as to be perpendicular to
the basal margin on the siphonal side, while in others this sub-auricle, if it may be so
called, is considerably shorter. The Barton specimens are generally the more oblique,
though not always so; the specimen figured from Brockenhurst is somewhat quadrate,
and corresponds in that character with the specimens figured in ‘Min. Conch.,’ from
Highgate. It is seldom that the outer surface is preserved, but in one specimen

a4 EOCENE MOLLUSCA.

from Barton, in which it is so, the right or flatter valve exhibits faint radiations ;
in one specimen of Mr. Edwards, (fig. 1, ¢,) of the left valve, these radiations are not
visible, although the outer layer is well preserved and perfect, showing irregular and
Jamellated and somewhat undulating lines of growth.

3. AvICULA PAPYRACEA, J. Sowerby. ‘Tab. XI, fig. 2, a—c.

AVICULA PAPYRACEA. Jd. Sow. Geol. Tr., 2d ser., vol. v, pl. 8, fig. 16, 1834.
— — Morris. Cat. Brit. Foss., p. 164, 1854.

Spec. Char. Av. testa tenuissimd, papyraced, obliqud suborbiculari, compressa, con-
centrice costulatd aut undulata ; auriculis minimis, inequalibus.

Shell very thin, papyraceous, obliquely orbicular; much compressed; concentrically
ridged or waved; ears small, unequal.

Longest diameter, 1} inch.

Localities. 6, Hampstead, Sheppy, Primrose Hill (Wefherell). f. a. Haverstock
Hill (Adwards).

“An extremely thin, pearly shell, sometimes assembled in considerable masses.”
(Sowerby.) Although specimens are by no means rare, the shell is always compressed and
distorted ; indeed, all I have seen are literally flat. In outward form it is unlike the
generality of shells of this genus, in having the hinge-line but little developed ; it resembles
a Posidonia in that character. A specimen in the Museum of the Geological Society, ap-
parently belonging to this species, is marked Southend (Warburton).

PINNA. JLinneus, 1767.

Generic Character. Shell equivalve, cuneiform, or wedge-shaped ; umbones at the pedal
extremity, siphonal region truncated and gaping; connexus ligamentous, linear; hinge
edentulous ; adductor muscle-mark subcentral, large, ill defined.

Animal the shape of the shell; the margins of the mantle with a double fringe, and
disunited except at the dorsal edge; foot elongated, grooved, spins a large, powerful, and
silky byssus; attached by triple muscles to the centre of each valve.

This is a marine genus. ‘The species range from low-water mark to sixty fathoms,
and the animals live generally buried in the sand or mud, with the pointed end of their
valves inserted ; they are gregarious, large numbers congregating in one spot.

The composition of the shell in this genus appears to be different from that i most of
the Mollusca, and, according to Dr. Carpenter, is made up of two very differently constituted
portions. ‘The outer or larger part of the shell is cellular, or composed of fibrous material,

BIVALVIA. 5D

placed at right angles to the surface, while the inner is laminated ; and as these lamin are
placed in an irregular, or rather in an undulating or wavy manner, they produce the
shelly substance called nacre, which, it appears, is more susceptible of destruction than the
outer or fibrous portion, and this in many of the secondary fossils is the only part of the
shell which is preserved. ‘The fibrous portion being very fragile, the shell separates
readily into fragments; and it is, therefore, a fossil not generally found in a perfect
condition. ‘There is also another peculiarity in the shell, being, as it were, divided by a
line down the middle, from the pedilateral to the siphonilateral margins, where it will
readily crack : so that fossils have frequently become of a quadrate form ; such, for example,
as Pinna tetragona, which has assumed that shape from pressure alone. Many of the
species of this genus will show, more or less, this tendency to angularity on the outside of
the valves. ‘The pearly or nacrous lining seldom extends more than half-way from the
beak ; frequently not so far. Many of the species attain to large proportions. Pinna
nobilis, of Poli, an inhabitant of the Mediterranean, has a shell that is said to measure three
feet and a half. This genus is as old as the Carboniferous Limestone, or perhaps the
Devonian; so far, of course, as can be determined by the shell alone; and it existed through
the intermediate periods, though not anywhere in great abundance. One of the aberrant
forms found in the Oolites has been thought, by Messrs. Morris and Lycett, to have a
difference sufficient to justify a generic separation, and they have adopted for it the
name of Zrichites ; the history of which, and the reasons for adoption, are given by these
authors in their valuable monograph of the Oolitic Bivalves. The principal difference existing
between the Oolitic shell and the true Pinna is in the inequality of the valves.

Pinna is on the verge of the ordinal division ; it more strictly belongs to the Dimyaria,
having two adductor muscles, but one is so near to the pointed extremity of the valves as
to be used more as a connector than as an adductor, while the other, the really useful one,
is situated quite in the centre of the shell.

1. Pinna arrinis, J. Sowerby. Tab. X, fig. 1, a—c.
Pinna aFFinis. J. Sow. Min. Conch., t. 313, fig. 2, 1821.
— — Mantell. Geol. Tr., 2d series, vol. iii, pt.i, p. 203, 1829.
— — Wetherell. Phil. Mag. and Journ., vol. ix, p. 464.
-— a Nyst. Foss. Belg., p. 275, 1843.
= = J. Sow. in Dixon’s Geol. Sussex, pp. 31, 117, 172, 226, 1850.
a _— Morris. Cat. Brit. Foss., p. 179, 1854.
~~ — D Orbigny. Prod. de Paléont., t. ii, p. 391, 1850.

Spec. Char. FP. testa cuneatd, trigond, regulari, costatd ; apice acuto ; siphoni-regione
truncata ; costis divergentibus; margine dorsali recto, margine ventrali sub-arcuato,
simplict.

Shell cuneiform or wedge-shaped, regularly trigonal; apex acute, truncated at the

56 EOCENE MOLLUSCA.

extremity of the siphonal region, and ornamented with diverging ribs; dorsal margin
straight, ventral margin slightly curved.
Length.—9 to 11 inches.
Localities —Highgate, Whetstone, Chalk Farm (Wetherel/), Sheppey, Newnham
(Prestwich), Bognor, (Edwards).

Our shell is ornamented with about sixteen or eighteen rather elevated rays or costa,
slightly imbricated, and sometimes undulating, with occasionally a small intermediate ray.

This species appears to have possessed a habit similar to that sometimes seen in
species of J/odiola ; two or three specimens are found together, the one enveloping the
other. A young fry probably occupies the shell of its parent, which it has never left, and
perhaps grows to its full size where it was born, filling entirely with its own shell the one
previously occupied by the mother. Mr. Edwards’ specimen shows this intimate union
of three individuals, each as nearly as possible of the same size. An imperfect specimen
of this species in the Museum of the Geological Society indicates a length of twelve

inches

2. Pinna arcuata, J. Sowerby. Tab. XI, fig. 8.

Pinna arcuatTa. J. Sow. Min. Conch.,, t. 313, fig. 3.
— — Prestwich. Journ. Geol. Soc., 1847, p. 405.
— — Morris. Catal. Brit. Foss., p. 180, 1854.
— — D Orbigny. Prod. de Paléont., t. 11, p. 391, 1850.

“ Nearly equilateral, ventricose, finely ribbed, arched.”

Longest diameter, #ths of an inch.

Locality —Uighgate (J. Sowerby).

“Nearly as deep as long; the hinge-line is gently curved; the opposite edge much
arched ; in other respects, this strongly resembles the last.”

«Having several specimens of this arched Pana from Highgate, exactly alike as well
in curvature as in size, I cannot but consider it a distinct species. It appears to be quite
different from P. incurva, Linn. : it occurs in Septaria.” (Sowerby).

The figure above referred to, and the description, are taken from ‘ Min. Conch.’

3. Pinna marcaRITackA, Lamarck. Tab. XI, fig. 9.

PINNA MARGARITACEA. Zam. Ann. du Mus., t. vi, p. 218, and t. ix, t. 17, fig. 8.
— — Defrance. Dict. des Scien. Nat., t. 41, p. 71.
— — Desh. Coq. Fos. des Env. de Par., t. 1, p. 280, pl. 41, fig. 15.
_— — Id. An. sans Vert. du Bassin de Par., t. 1, p. 35, 1860.
— — Nyst. Coq. Foss. Belg., p. 274, pl. 20, fig. 9.
— _ J. Sow. in Dixon’s Geol. of Sussex, pp. 94, 117, 172, 226.
_ — Morris. Catal. Brit. Foss.,p. 180. 1854.

BIVALVIA. 57

Spec. Char. “ Testé elongata, cuneiformi, trigond, angustd, sublevigatd, vel sulcis
longitudinalibus, superficialibus, undulatis instructd, extis fused, fibrosd, intus albd,
margaritacea.”

‘« Shell elongate, wedge-shaped, trigonal, nearly smooth, or with superficial and longi-
tudinally undulating rays, externally brownish or dusky and fibrous, within white and
nacreous.”’

Length, is

Localities.—Bracklesham (Dizon), Highgate (Sowerby).

France, Grignon, Parnes (Desf).

“This appears to have sharper ribs than P. afinis, but probably they are the same
species differently preserved.” (J. Sowerby.)

Our figure is taken from a specimen in the British Museum in the late Mr. Dixon’s
collection ; this species appears to have more numerous and finer rays than any I have seen
upon the young state of P. afinis.

4, Pinna prrirormis, S. Wood. Tab. X, fig. 2, and Tab. XI, fig. 10.

Pinna — n.s. Prestwich. Quart. Journ. Geol. Soc., vol. iii, p. 370, 1847.

Spec. Char. P. testa tenui, tumidd, inflata, infundibuliformi, costatd ; costis numerosis,
subundulatis ; margine dorsalt subrectd ; margine ventrali incurva.

Shell thin, tumid, or inflated, funnel-shaped, costated ; ribs numerous, thin, and slightly
undulating ; dorsal margin nearly straight, ventral margin curved.

Length, 2

Locality. Cuffell, near Basingstoke (Prestwich).

The specimen figured is from the cabinet of Mr. Prestwich, and I coincide in his
opinion that it is specifically distinct ; it is unlike any other species that I have seen.
It differs from P. afinis in form, and it approaches nearer to P. arcuata; but it is not
so curved as that species, either in the dorsal or ventral margin, and it is considerably more
expanded than either of those species. A small portion only of the shell is left, and tlie
rays are nearly obsolete; what there are remaining appear to have been smaller and more
numerous, and also more equal, than those of afiais, but its presumed distinction is founded
upon the expanded character. I cannot but imagine this to be natural, for although there
is a tendency in many species of this genus to become inflated by a collapse or fracture
in the centre, I do not see in this any angularity, but a regular curvature in the valves.

58 EOCENE MOLLUSCA.

DREISSENA. Van Beneden, 1834.

Mytitus. Lam. and Goldf. Conereria. Partsch, 1837.
EnocePHatus. Mumst., 1831. Mytitomya. Cantraine, 1837.
Myturina. Cantraine, 1834. Mytitimerta. Conrad, 1837.
DytHaLmiA. Jay, sec. Gray. CorLtoconta. Bronn (laps. calam.), 1837.
TicHOGONIA. Rossmaesler, 1835. | /Exocepuatus. Herrm., 1846.

Generic Character. Shell equivalve, inequilateral, ovately trigonal or obscurely wedge-
shaped ; umbones terminal, pointed ; hinge edentulous ; valves obtusely keeled, with a
slight byssal sinus ; one muscular impression, immediately beneath the umbones, supported
upon a shelf, projecting inwardly ; impression of pedal muscle single; anal adductor
large, excentric ; connexus bipartite.

The animal (A/ytilus polymorphus) with the mantle closed, except for the foot and
byssus. Siphons unequal; anal opening small, conical, and plain; branchial opening
prominent and fringed ; foot-muscle short and thick.

The name of Hnocephalus of Minster seems to have priority of date, but, according to
M. Bronn, it was merely given to the shell without figure or description; it therefore
yields to a subsequent claim, and this is divided between Mytilina, Cantraine, and Dreissena,
Van Beneden ; both of which names were proposed for the shell in the same year. Bronn
has awarded the right to Van Beneden, who, he says, is entitled to priority. The name is
also in general use.

This is a fresh-water mussel; the typical species, A/yt. Volga, Chemn., is a native of
the Aralo-Caspian rivers, whence it has been brought to this country on foreign timber,
and it has now become naturalised with us. It differs principally from M/yéidus in having
a calcareous plate immediately under the umbo ; in other respects it resembles the general
form of the mussels. M. Nyst enumerates fourteen species, eight of which are fossil
from the Tertiaries of Germany, France, Belgium, and the Crimea; but a fossil said to
belong to this genus has been found in the coal measures. The species, though probably
more inclined to fresh-water, were capable of living in estuaries where the water was salt.

This, like the genus Unio, is very variable in regard to the solidity or substance of the
shells of different species ; some are thick and heavy, while others are quite the reverse.
This is, perhaps, truly Dimyarian, with two adductor muscles, and the animals possess
distinct but short siphonal tubes, indicating, by the inflexion in the mantle-mark, probably
a slight difference in their extent of protrusion.’

1 Dreissena is said to be distinguished from Mytilus as much by the intimate structure of the shell
as it is by other characters.

BIVALVIA. 59

DreissenA Brarpir, Fawas St. Fond. Tab. XII, fig. 3, a—e.

Moutsr, Faw. St. Fond. Ann. du Mus,, t. viii, t. 58, figs. 11, 12.
Mytitus Brarpirt. Brongn. Terr. cale. Trap. du Vincentin, t. 6, fig. 14, 1823.
— — Goldf. Petr. Germ., vol. ii, p. 271, t. 129, fig. 10.
_- — J. Sowerby. Min. Conch., t. 532, fig. 2, 1826.
os — Bronn. Leth. Geog., t. ii, p. 923, pl. 39, fig. 10, 1836.
— — Nyst. Rech. Coq. foss. Hoess. et Kl. spaw., p. 13, No. 22, 1836.

— — var. 8 ? Basterot. Bordeaux Foss., No. 2, p. 78.

?— Basrerotu. Dujardin. Tr. Géol. Soc. Fr., vol ii, p. 269.

?— acuTrrostris. Goldf. Petr. Germ., t. v, pl. 129, fig. 11, p. 272.
?_s sparuunatus. Id. : - fig. 12.

Conceria Basrerot1? Desh. Conch., 650, t. 37, figs. 15, 16.
DreissENA Brarpiut. Morris. Catal. Brit. Foss., p. 202, 1854.
— — Pictet. Traitée de Palzont., pl. 81, fig. 11.
— Basrerotr. Myst. Conch. Foss. Belg., p. 265, pl. 20, fig. 7 a—e.
— Sowrersyl. D’Orbigny. Prod. de Paleont., t. 11, p. 425, No. 1637, 1850.

Spec. Char. D. testa ovatd vel elongato-cuneald ; levigatd, obtusé carinatd ; umboni-
bus acutis ; septo cochleato. .

Shell ovate or elongately wedge-shaped, smooth, and obtusely carinated; beaks sharp
and pointed ; septum concave.

Length, 7ths of an inch.

Localities. Hordwell, Headon Hill (Fordes).

Belgium, Limbourg (JVys¢), Weisenau, Env. de Mayence (4. Brongniart).

This little shell is abundant in the fine sandy stratum at Hordwell which has yielded
so many beautiful vertebrate fossils. Upwards of a hundred specimens were obtained by
myself, congregated in and around the upper jaw of Alligator Hantoniensis. It is pos-
sible that the decomposition of the flesh of the dead reptile may have rendered the water
at that place favorable to the multiplication of the mussel. I found the shell elsewhere,
but in no other place in so great abundance.

My specimens are variable in outline; the proportions in some are from 23 to 1, while
in others they are not more than 13 to 1, the more elongated being also the more
tumid. The umbo is a little inflected, and in some specimens there is a flattening on
the siphonal region. The shelf is of a moderate size, and is not entirely occupied by the
muscle, the mark of which is indented on it, and is of a roundedly oval shape. The
cartilaginous portion of the connexus extended about two fifths of the longest diameter of
the shell, and, like that of Mytilus, it was nearly covered by the dorsal edge. Many
specimens of a small Serpula (tenuis) were found with this mussel in association with
numerous specimens of Limnee, Cyrene, &c., and in one of the specimens there is
what appears to be the arenaceous case of a Sadella (fig. 3a). We have, thus,
supposed marine animals living in fresh water with Limnee, or we have the supposed

60 EOCENE MOLLUSCA.

fresh-water Limneee in company with salt-water animals, as previously noticed by Mr.
James Sowerby in his ‘Mineral Conchology.’ I am inclined to think the water where
these animals were deposited was quite fresh, although Limnez have been found living
in saline marshes; the reptile was probably stopped by a bend of the river or by
some impediment in the stream; the presence of a large number of the scales of
Lepidosteus in this layer of sand indicates the greater probability of its having been more
of a fresh-water deposit than brackish.

D. Brardii is given by Mr. Prestwich in his list of the organic remains of the
Woolwich and Reading series (Jour. Geol. Soc., 1847, p. 117); he says, however, at
p. 120 (/)—‘this shell is here in too imperfect a state to admit of a positive
determination.”

‘'wo specimens, with the name of Mytilus Brardii, were obligingly sent to me
many years ago by the Comte du Chastel, and to these was attached the locality of
Bordeaux. I presume they are what have since been called Dreissena Basterotti.
On a close comparison with the British fossil, these specimens present the following
differences : they are rather more pointed, less curved at the umbo, and they have an
obtuse elevation or sort of ridge at the most inflated part, which has probably caused
them to be called “ subcarinated.”” Whether these slight differences be permanent or
whether they are such as will constitute a specific distinction, the few specimens of the
Bordeaux shell that I have seen will not permit me to give a decided opinion.

MYTILUS. JLinneus, 1758.

Generic Character. Shell equivalve, wedge-shaped, acuminated, rounded on _ the
siphonal side; umbones pointed, terminal; hinge-teeth few, minute, sometimes obsolete ;
muscular impression at the umbo small and narrow; pedal impressions two in each
valve ; connexus bipartite, marginal ; interior of shell nacreous.

Animal elongate, with the lobes of the mantle partly fringed, plain in the anal region,
and slightly projecting ; disconnected except where there is a separation for the siphonal
openings ; adductor muscles very unequal in size ; foot cylindrical, furnished with a gland
and groove; byssus strong and coarse.

This genus is generally marine, though sometimes estuary in its habits, and, I believe,
M. edulis is known occasionally to live with Limneeze, &c., when the water is fresh. This
common edible mussel frequents mud banks, and, as it is well known, is more often found
where it has been deserted by the retiring tide; others inhabit the sea at considerable
depths. In the recent state the genus numbers probably fifty species, and these have a
very extensive geographical range, taking in the whole circumference of the globe. The
generality of the species are extra-tropical. Fossil species are abundant, and are said to
be found in rocks of the Permian age.

BIVALVIA. 61

1. Mytinus arrinis, J. Sowerby. Tab. XII, fig. 1, a—d.

Myriuus arrinis. J. Sow. Min. Conch., t. 532, fig. 1.
— — Morris. Catal. Brit. Foss., p. 215, 1854.

Spec. Char. M. testaé tenui, elongato-cuneaté vel obliqué-oblongatd, laevigata, sub-
carinatd ; margine dorsali subrecto ; intus margaritacea ; cardine edentato.

Shell thin, elongately wedge-shaped, or obliquely oblong, smooth, subcarinated ; hinge-
margin nearly straight ; interior pearly ; hinge without teeth.

Length, 2 inches.

Localities. 6, Barton; a, c, d, Colwell Bay, Headon Hill, Whitecliff Bay, Hordwell
(Edwards).

This species much resembles in outline some of the varieties of the common mussel,
but it is carinated, that is to say, it is obtusely ridged at the most tumid or inflated part,
and it is generally less rounded and more flattened in the siphonal region than in the
recent British species; it is also very thin, and quite free from teeth at the umbo.
Although not abundant, this fossil presents a good deal of variation in outline, the dorsal
margin being much longer in some specimens than in others; but this kind of variability
is common to the genus, and it may be seen in excess in the varieties of M. edulis.

2. Mytitus stricitLatus, S. Wood. ‘Tab. XII, fig. 2, a, 0.

Spec. Char. M. testd minima, tenui, ovato-cuneatd, obliquda, incurva, inflata, radiatim
striatd, striis obtusis conveais ; margine dorsali arcuatd, et crenulatd ; margine ventrali sub-
incurvad ; area cardinali denticulatd.

Shell small, thin, and ovately wedge-shaped, oblique, incurved, tumid, radiately striated ;
striz obtuse, rounded; dorsal margin arched and strongly crenulated ; ventral margin
slightly concave ; hinge-area denticulated.

Length, 3; inch.

Locality. Barton (£dwards).

Half a dozen specimens of this pretty little shell appear to offer good distinguishing
characters. The connexus was short, and situated within the rounded dorsal margin, but
its action was over a fulcrum, and it was probably visible when the valves were closed.
There are about half a dozen denticles in the hinge-area, variable in size, the two on the
pedal side being the larger, and the dorsal margin outside the ligament is strongly den-
ticulated, like Modiolarca. The strize, or rather ribs which ornament the shell, are large,
prominent, and rounded, not angular, and the spaces between them are as broad as the
ribs ; an intermediate ray may be occasionally seen on the dorsal and siphonal regions as
the shell enlarges. This closely approaches A/odiola, having a trifling extension beyond
the umbo.

62 EOCENE MOLLUSCA.

MODIOLA. Lamarck, 1801.

Generic Character. Shell equivalve, inequilateral, irregularly and roundedly oblong or
trapezoidal ; valves sometimes smooth, sometimes entirely covered with radiating striz, at
others the central portion is smooth, with the lateral extremities striated ; pedal region small,
umbones subterminal ; hinge-margin generally smooth, sometimes crenulated, edentulous ;
connexus bipartite; impressions of the adductors unequal; shell slightly gaping for the
passage of a byssus; epidermis in the recent state often produced into long, beard-like
fringes ; interior of shell nacreous.

Animal with the margins of the mantle without fringe; foot cylindrical, elongated ;
spins generally a fine and ample byssus.

This is, as it were, an emanation from the last, with a further approach towards the true
Dimyaria. Unlike the preceding, in which the umbo is pointed and terminal, the animals
of this genus extend their shells beyond the beak on the pedal side, altering their form
from the wedge-shape of A/ytilus to the sub-rhomboidal shape of this. In /ytlus the
oral adductor is immediately beneath the umbo, but in this genus it is beyond it, and on
the inner side of the cartilaginous portion of the connexus there is generally a deeply
impressed mark of the pedal muscle.

The habits of these animals in the living state are variable ; many of the species spin a
byssus, by which they are constantly fixed, and this byssus in some is so enlarged as to
envelop the shell in a kind of nest; others bore into the test of an Ascidian; while for
some cylindrically formed shells, such as JZ. ithophagus, Linn., a habitation is excavated
in corals, shells, and the hardest limestone rocks; these latter, from such habits and
their cylindrical form, have by some naturalists been considered as entitled to a distinct
generic position (Zz/hodomus, Cuv.). These boring shells are found in the Oolites, in the
thick shells of Zrzchztes and Astarte, as well asin the rock itself, and shells resembling them
have been met with in the Palzozoic formations.

Crenella is another section of this genus which has been put forward as a claimant for
isolation ; the principal, perhaps the only, distinction is the striation of the exterior, but
this in itself is insufficient. Shells included in the above diagnosis possess every possible
variation. In some the shell is quite smooth or naked, but in others it is less than half orna-
mented, increasing the extension in striation until many are entirely covered; while some
have the centre smooth, with the extremities striated. This, again, is in one species
reversed, the strize only occupying the central portion.

Myopara is a name proposed as a genus by Lea in substitution of Sfalagmium, Conrad,
1833 (Morton’s ‘Synopsis,’ App., p. 8), for the reception of a small Eocene fossil of
America, which is possibly an aberrant form of this genus, as suggested by Mr. Wood-
ward, belonging to the section Crenella. It is of amore ovate outline than are the generality

BIVALVIA, 63

of the species of this genus; it resembles M/y/i/us decussatus, Montague, which Brown made
the type of his genus Creze//a. This small and apparently rare shell of Lea is the only
recorded fossil of the Eocene period belonging to the Mytiloid family from the American
beds that I am acquainted with. A few small species from the Paris basin have been
recently figured and described by M. Deshayes under the generic name of Crenel/a. These
French fossils have a more rounded form than any of our English species.

Modiola is generally a marine genus, and it is found in most parts of the world, and
at various depths ; two or three species have, however, been found in estuaries and where
the water is sometimes fresh. Mr. McAndrew gives the vertical range of MZ. modiolus
from the shore to 100 fathoms.

1. Moptoza pupressa, J. Sowerby. Tab. XII, fig. 4.

Mopiota pErrEssa. J. Sow. Min. Conch., t. 8, three upper figs., 1812.
— — Prestwich. Proc. Geol. Soc., May, 1847, p. 404.
— — J. Morris. Catal. Brit. Foss., p. 211, 1854.

—_ — Smith. Strat. Syst. Org. Foss. Lond. Clay, p. 2.

Spec. Char. M. testa tenui, elongatd, obtusé-cuneaté aut irregulariter trapeziformi, com-
pressa, levigatd ; umbonibus minutis, depressis, subterminalibus ; pedi-regione brevt, siphoni-
regione elongata et latiore ; margine ventrali subrecta.

Shell thin, elongate, obtusely wedge-shaped or irregularly trapeziform, compressed,
smooth ; umbones small, depressed, and nearly terminal; pedal region short and rounded ;
siphonal region long and broad ; ventral margin nearly straight.

Length, 2 mches.

Localities. Highgate (Sowerby), Sonning Hill (Prestwich).

“This shell is two and a half as broad as it is long, and thin; the margin even and
very regularly curved; it is altogether very flat, particularly so at the anterior (?) side;
the beaks are very slightly prominent and are rounded ; lines of growth faint ; external coat
shining and pellucid, internal pearly. It is difficult to preserve, that being so extremely
tender, the clay shrinks in drying, the shells crack and scale off in pieces, else the appear-
ance of an epidermis is almost to be recognised.” (J. Sowerby.)

Specimens of a shell strongly resembling this from Harwich, as also from the Barn Rock,
near Bognor, and from Hollyport, are in the Museum of the Geological Society, but they
are not perfect enough for fair determination.

64 EOCENE MOLLUSCA.

2. Mopioxa Desnayesil, J. Sowerby. ‘Tab. XIII, fig. 14, a, 4.

Lirnopomus DesnayesiI. J. Sow. in Dixon’s Geol. of Sussex, pp. 94, 171. t. 2, fig. 28.
— a Morris. Catal. Brit. Foss., p. 207, 1854.
Mopio1La LITHOPHAGA. Desh. Coq. Foss. des Envy. de Par., t. i. p. 267, t. 38, figs. 1U—12.
— —- Pictet. Traité de Palzont., vol. iii, p. 584, pl. 81, fig. 9.
MyvILus LirHopHaGus. Desh, Trait. Element, t. 37, figs. 5, 6.
LyfHODOMUS SUBLITHOPHAGUS. D’Orb. Prod. Paleont., p. 391, No. 1083.
— — Bellardi. Catal. Ragion. dei. foss. Numm. d’Egitto, p. 26,
No. 62, 1854.
Mopiota Desnayesil. Desh. An. sans Vert. du Bassin de Par., t. ii, p. 18, 1860.

Spec. Char. M.“ testa elongaté cylindraced, recta ; anticé tumidiore ; extremitatibus
obtusis ; strits longitudinalibus posticé brevibus ; striis transversis irregularibus, decussatis.”

Length, \ inch.

Localities. Bracklesham (Dizon).

France, Parnes, Chaumont (Desh.), Egypt, Sinde (Bellard).

The figure above referred to is a copy of the one in Mr. Dixon’s work. The specimen
cannot now be found.

The Paris basin shell, when first described, was doubtfully considered to be a variety
of the existing species, under which name it was then published. M. Deshayes, in his
‘Hist. des An. sans Vert. du Bassin de Paris,’ p. 18, has adopted the above specific
one, which was given to it by Mr. Jas. Sowerby, who considered it sufficiently different to
be entitled to a distinct position, and M. Deshayes is now of the same opinion. I regret
not having been able to see the British fossil.

3. Mopiona pimtpiata, S. Wood. ‘Tab. XIII, fig. 5.

Spec. Char. M. testa tenui, depressd, subcylindraced, elongatdé ; pedi-regione brevi,
rotundatd, valdé inequilaterali ; dimidiatim radiata, umbonibus depressis ; margine ventrali
rectiusculo.

Shell thin, depressed, nearly cylindrical, elongate; pedal region short, rounded; one
half of the shell striated or rayed, the other smooth or naked; ventral margin nearly
straight.

Length, iths of an inch. id

Locality. Wighcliff, Barton (Hdwards).

I have seen only a single specimen of this elegant species, but it is well marked ; it
approaches the cylindrical and stone-eating shells called Lithodomus. The strive cut
the shell diagonally into two nearly equal parts, covermg the whole of the siphonal region
and extending from the umbo to the extremity of the margin, the other half of the shell is

free from these markings, with the exception of the extreme margin on the pedal side,
which has a few rays or ridges.

BIVALVIA. 65

‘This species much resembles J/. Bernayi, Desh. ( An. sans Vert. du Bassin de Paris,
f. 11; p. 18, Pl. 74; figs..13

smaller pedal region. Our shell is ornamented between the rays on the siphonal region

16), particularly in the outline, but it differs in having a

with elevated ridges or regular lines of growth, decussating, as it were, the interspaces.

Mig. 15 is the cast of a shell in the late Mr. Dixon’s collection of Eocene fossils in the
British Museum; unfortunately it is without a locality. It resembles in outline the above
species.

4. Moprtona porsata, Morris. Tab. XII, fig. 2.
Mopiota porsata. Morris. Geol. Journ., vol. x, pt. i, p. 158, pl. 11, fig. 14, 1854.

“A rare species. ‘Ihe specimen is hardly sufficiently perfect for an exact determination
of its characters. It differs from the preceding species (JZ. J/tfchelli) in the umbo not
being so terminal, and the form being less spathulate and more compressed.” (Jorris.)

Locality. Sundridge (Prestwich).

The only specimen that [ have seen is the one figured, and I am unable to add to the
description given by the proposer of the species. ‘The prominent diagonal ridge is pro-
bably accidental, but the pedal side is considerably extended, if it be natural and not
forced out by pressure.

5. Mopiona eLxeans, J. Sowerby. Tab. XII, fig. 5, a—c.

Moprona ELEGANS. J. Sow. Min. Conch., t. ix, left-hand figures.
— — J. Morris. Catal. Brit. Foss., p. 211, 1854.
Mytitus nrLeGans. D’Orbigny. Prod. de Paléont., p. 391, 1850.

Spec. Char. Testé tenui, ovato-clongatd vel subtrapezoidah, tumidd, subcarinald ;
pedi-regione brevi, siphoni-regione rotundd ; margine dorsali paulo angulato ; strivs
utroque divaricatis, spatio mediano levigato ; margine ventrali subrecto.

Shell thin, elongately ovate or subtrapezoidal, tumid, and obtusely keeled ; pedal region
short and rounded; dorsal margin obtusely angulated or curved; striz on both sides
divergent, middle plain ; ventral margin slightly contracted ; shell nacreous.

Length, \¥ iweh.

Localities. a, Highgate (Wetherell), Bognor, Richmond Park (J. Sowerby), Clewer
Green? (Prestwich); c, Bracklesham, Barton (2dwards) ; 6, Hordwell (Zdwards).

This appears to have extended from the lowest to the uppermost of the Hocene
deposits ; it is not rare, and is subject to considerable variation. It is less pointed on the
pedal side than JZ. hastata. Our shell is thin, and some specimens are so irregularly
tumid as to form an obtuse keel or ridge from the umbo to the edge of the ventral margin
of the siphonal region, but in others this is by no means prominent, as if this keel were

9

66 KOCENE MOLLUSCA.

in some degree accidental. The striae on the siphonal region of the shell extend over
more than half the surface, and those upon the pedal region are few and faint, sometimes
obsolete. Mr. Sowerby speaks of a denticulated margin and a dentated hinge (note, p. 32,
Min. Conch.), and says that it is very abundant at Highgate. In the specimens from
Bracklesham the ridges or rays are small, with broad interspaces; in those from High-
gate the ridges are about the same breadth as the interspaces ; those from Bramshaw have
broad, flat ridges, with only narrow lines of separation, the Highgate specimens being
intermediate. Casts of this or of some proximate species found at Harwich are in the
Museum of the Geological Society.

There are three different forms which I have figured, considering them all to belong to
the same species, from my inability to draw a line of distinction between them. Among
the Highgate specimens elongated as well as abbreviated specimens may be seen ; fig. 5 a
looks like a distortion.

6. Mopioua eximta, S. Wood. PI. XIII, fig. 6, a, 3b.

Spec. Char. M. testa minima, ovato-ellipticd, obliqua, valde inequilaterali, pedi-regione
brevi, rotundatd ; siphoni-regione latiore ; spatio submediano parvo, levigato ; striis tenu-
thus, evilissimis ; margine ventrali arcuato.

Shell small, ovately elliptical, oblique, very inequilateral ; pedal region small, short, and
rounded ; siphonal region broader ; central region free from strize, ventral margin rounded.

Length, 7th of an inch.

Locality. Wigheliff, Barton (Ldwards).

A specimen of each valve of this elegant little shell is in the cabimet of Mr. Edwards,
and these are ali that I have seen. I imagine them to be full grown, as the muscular
markings are deeply seated; the anal adductor impression is large, of an ovate form, and
situated a little beyond the hinge-line; the one in the pedal region is about half the size,
situated near the umbo; the two are connected by a distinct mantle-mark. The striz
cover the surface of the shell, excepting a small space on the pedal side of the ventral
region; this naked space occupies about one fourth of the surface, and it is less, com-
paratively, than upon any of our larger species covered with this kind of ornament.
This character more especially, as well as a difference in outline, will, I consider, dis-
tinguish it from the fry or young of any other species with which it was associated.
The inner margin of our shell is crenulated all round, excepting the small space in the
ventral region; the crenulations on the pedal side are few and large. The umbo is
moderately elevated, and the shell, for its size, appears to be strong.

BIVALVIA. 67

7. Mopioua FLABELLULA, S. Wood. Tab. XIII, fig. 9, a—e.

Spec. Char. M. testa tenui, elongata, irregulariter trapeziformi ; pedi-regione parva,
brevi ; siphoni-regione elongata et latiore ; radiato-costulata, costulis maynis, depressis, ali-
quando dichotomis ; margine ventrali subsinuato.

Shell thin, elongate, irregularly trapeziform ; pedal region small and short; siphonal
region elongate and broader; radiately rayed with broad, depressed ribs or riblets, which
sometimes divide or bifurcate; ventral margin slightly curved.

Length, 1 inch.

Locality. Wempstead (Ldwards).

Three specimens of this shell have lately come into the possession of Mr. Edwards, and
I think they are entitled to be considered as belonging to a distinct species. ‘lhe shell is
different from JZ: nodulifera in its more elongated form and in the radiations not being
noduliferous. JZ. pectinata, Lamarck, approaches it in some characters, but the outline is
different, and that shell has more numerous radiations.

8. Moprozta nastata, Deshayes. Tab. XII, fig. 6, a, 6.

Mopiota HastaTa. Desh. Coq. Foss. des Env. de Par., t. i, p. 361, pl. 38, figs. 13, 14,
1824.
— — Id. An. sans Vert. du Bassin de Par., t. ii, p. 13, 1860.
— ELEGANS. Jd. Sow., in Dixon’s Geol. of Suss., p. 94, pl. 44, fig. 13, 1850.
Myriius nastatus. Desh. Ency. Méthod. Vers., t. ii, p. 563, 1830.

Spec. Char. M. testa ovato-elongatd, subulata, valde recurva ; dorso oblique angulata ;
striata ; striis divaricatis, spatio mediano levigato ; pedi-regione brevi, profunde crenulatd.

Shell ovately elongate, tapering, greatly recurved; dorsal margin obliquely angular ;
striated striz divaricating; central space smooth; pedal region short, pointed; margin
deeply crenulated.

Length, 14 ch.

Localities. Brook (Zdwards), Bognor.

There is a considerable curvature in the ventral margin of this species, and the shell
is elevated into an obtuse keel curving from the umbo; in these characters it differs
from JZ. elegans, and it appears to be identical with the Paris basin species. The whole
of the siphonal region is deeply and coarsely striated; these strize bifurcate towards the
siphoni-lateral margin, and extend a little over the obtuse keel or ridge, beyond which
they immediately become finer, and are soon lost in the naked ventral region. The
pedal region is very small, angular, or obtusely pointed, and on the margin of this are a
few coarse, radiating striee or ridges. The ventral region is strongly marked with lines of
growth.

68 EOCENE MOLLUSCA.

9. Mopiona Mircuenis, Morris. Tab. XIII, fig. 10.

Mopiona Mircuetu. Morris. Geol. Journ., vol. x, pt. 1, p. 158, t. 2, figs. 12, 13, 1854.
— — Id. Catal. Brit. Foss., p. 211, 1854.

Spee. Char. “ M. testa tenmi, levi, subtrigond, anticé obtusd, posticé dilatatd ; cardine
marginal recto.”

“A somewhat trigonal, depressed, and dilated shell, with the umbones obtuse, the
dorsal line straight, the byssal margin nearly straight or but very slightly curved, the
surface nearly smooth or faintly marked by lines of growth.” (Morris.)

Length, \ inch.

Localities. New Cross, Deptford, Lee and Blackheath (d/orris).

“This species is near to Dreissena antiqua, Mcll., but the dorsal margin is more pro-
duced, and the general character of the shell more spatulate.”

“Not rare in the upper part of the Woolwich series, but it is rarely found perfect.”

Mr. Prestwich’s cabinet.

10. Moprona nopunirera, S. Wood. ‘Tab. XIII, fig. 8, a, 6.

Spee. Char. M. testa tenui, wrregulariter trapeziformi, valde inequilateral: ; ped:-
regione pared, margine subrolundald, siphoni-regione magnd, dilatatd ; eatis radiatim
striata, striis magnis, bifurcatis, noduliferis ; margine ventrali incurva.

Shell thin, irregularly trapeziform, very inequilateral; the pedal region small and
rounded, siphonal region expanded, covered with large, birfurcating, and nodulous radia-
tions; ventral margin somewhat curved.

Length, § an inch.

Locality. Barton (Ldwards).

One specimen is all that 1 have seen, but its ornamentation is so different from
that of any other species that I think it must be distinct. The strie which cover the
entire surface are peculiar in bifurcating at a very early period. Near the umbo they do
not amount to more than half a dozen, while at the outer margin of the siphonal region
as many as thirty-five may be counted; these stria are rather broader than the interme-
diate spaces, and they are ornamented with a small knob or thickening at regular

distances.

11. Mopiona Nystu, Avcke, MSS., sec. Myst. ‘Tab. XII, fig. 8, a, 6.

Myvitus Nysru. Nyst. Coq. Foss. Belg., p. 270, pl. 20, fig. 8 0.
— oe Id. Rech. Coq. Foss. de Hoesselt et KI. Spau., p. 14, No. 3a, pl. 3,
fig. 35, fide Nyst.
— HastTarus. Goldf. Petr. Germ., p. 179, pl. 131, fig. 13.

BIVALVIA. 69

Spec. Char. M. testa elongato-ovatd, obliqud, incurvd, striata ; striis numerosis, radi-
antibus, divaricatis, spatio mediano lavigato ; pedi-regione brevi, margine rotundato, crenu-
lato ; regione dorsali subarcuato.

Shell elongately ovate, oblique, incurved, striated; striae numerous, radiating, and
divaricating ; middle portion smooth; pedal region short, with rounded and crenulated
margin; hinge-line somewhat arched.

Length, 2 inches.

Localities. Brockenhurst (Ldwards).

Belgium, Hoesselt (JVys?).

‘his does not appear to be rare in England.

I agree in opinion with M. Nyst, that this is quite distinct from J/. hastata, Desh.,
but that it is the one so called by Goldfuss. Our shell agrees precisely with the Belgian
fossil. ‘This appears to be intermediate in form between JZ. elegans and MW. hastata ;
it has a greater curvature in the ventral region than that of the former, but less so than
in the latter, and it attains to a greater magnitude than either. The rays multiply upon
the older portion of the shell, having there double the number that there are upon the
younger shell. The ventral region is free from rays, and the hinge appears to possess two
or three teeth. These are wholly irrespective of the denticulated margin produced by the
few coarse rays which cover the pedal region.

12. Moprona Prestwicay, Morris. ‘Tab. XIII, fig. 7.

Mopro.a Prestwicuit. Morris. Mem. Geol. Surv., pp. 46, 147, t. 2, fig. 5, 1856.
— Nystiana. Forbes. Ut supra (name only).
— — Morris. Catal. Brit. Foss., p. 211, 1854.

Spee. Char. ‘* M. testa ovato-elongald, angustd, subdepressd, superné dilatatd, longitu-
dinaliter striata ; striis numerosis obscuris, margine crenulato ?”

“An ovate, elongate shell, of somewhat spathulate form, marked with numerous
radiating but rather obscure strie.” (AZorris.)

Length, 1 inch.

Kocality. Hempstead Chiff (dorris).

The name of Wystiana was originally given to this species by the late Prof. U. Forbes, as
written upon the plate above referred to. ‘There was, however, no description appended,
and the specific name having been already used in this genus, the describer considered
himself justified in revoking the one first imposed, and I have for the samme reason fol-
lowed his example.

A mass of clay in Mr. Edwards’s cabinet, with a surface an inch and a half square, has
not less than twelve specimens of various sizes upon it, with the exterior upwards, and it
is somewhat singular they should all lie in that position ; they appear to be single valves.

70 EOCENE MOLLUSCA.

With them are numerous specimens of a species of Hydrobia, from which I should
imagine it to be an estuary species. ‘The exterior is covered with exceedingly fine striae,
those on the siphonal region being rather larger and more distant, and the pedal side of
the ventral margin is slightly contracted, giving a gentle curvature to the base. The
hinge-line is straight, and extends half the length of the shell. The pedal region occu-
pies about one fifth of the specimen.

13. MopioLa premaa, S. Wood. Pl. XIII, fig. 4, a, 6.

Spec Char. M. testa minutd, oblongo-ellipticd, tenuissimd, tumidd, striata, striis in
medvo interrupts ; pedi-regione parvd, subacutd, angustiore ; margine dorsali subangulata ;
margine ventrali subrecta.

Shell minute, elliptically oblong, very thin, tumid, striated, with a small, naked space
in the ventral region ; pedal region small, pointed; dorsal margin obtusely angulated ;
ventral margin nearly straight.

Length, 3th of an inch.

Locality. Barton (Ldwards).

This small and elegant little shell differs from JZ. evimza in the outline, and also in the
striation. ‘The exterior is covered with strize, except on a small space of the ventral region,
which is naked. ‘The contour of this species is less rounded than that of eaimia, and the
striee are fewer and broader. The dorsal edge is covered with crenulations, like those on
the so-called Aodiolarca, but these are merely extensions of the prominent rays which
project at the margin.

14. Mopiona semi-NuDA, Deshayes. ‘Tab. XIII, fig. 1, a, 6.

MopIoLa sEMI-NuDA. Desh, Coq. Foss. des Env. de Par., t. i, p. 264, pl. 39, figs. 20—22.
—- — Morris. Catal. Brit. Foss., p. 211, 1854.
— — Desh. An. sans Vert. du Bassin de Par., t. ii, p. 12, 1860.

MyvILus spmi-Nupus. Desh. Ency. Meth. Vers., t. ii, p. 569, No. 36, 1850.
— — D’ Orbigny. Prod. de Paleont., t. ii, p. 424, No. 1634, 1850.

Spec. Char. M. testé ovato-ellipticd, cordatd, tumidd, tenuissimd, fragili, striata ;
sirius eatlissinis ornatd ; spatio submediano lavigato ; umbonibus minimis, depressis, sub-
ferminalibus.

Shell ovately elliptical, heart-shaped, inflated, very thin and fragile, ornamented with
very fine strize ; centre portion plain, or free from radiating ridges; umbones small, de-
pressed, and nearly terminal.

Length, #ths of an inch; heighé, } an inch.

Localities. Barton (Hdwards).

France, Senlis, Grignon (Deshayes).

BIVALVIA. 71

This is an extremely delicate shell, and very rare; a few specimens, however, are
quite perfect, and will bear a fair comparison. ‘The shell to which it most nearly
approaches is the common British species, 17. marmorata, but it differs essentially in several
characters; these have been pointed out by M. Deshayes, the founder of the present
species. The British fossil appears to correspond with the French shell, so far as depen-
dence can be placed upon figures and descriptions, and I have not been able to see a
specimen of the latter. The striae on the pedal region are very large or broad, becoming
narrower towards the central smooth space, where they terminate with two or three very
fine lines; the radiations on the siphonal region are not so broad; all the rays are flat,
with narrow depressions between them. ‘The smooth or naked central space occupies
about one third of the surface of the shell, and the lines of growth are here distinctly
visible, sometimes raised almost to ridges. ‘The rays on both regions of the French shell
are represented of the same size, but they are not so on ours.

One of Mr. Edwards’s specimens has enclosed within its valves no less than three
others, enveloping one another; one of these enveloped specimens is in a reversed
position.

15. Mopioxa simpxex, J. Sowerby. Tab. XII, fig. 7, a, 0.

MopIoLa SIMPLEX. J. Sow., in Dixon’s Geol. of Suss., pp. 117, 225, t. 14, fig. 16, 1850.
_ — Morris. Catal. Brit. Foss., p. 212, 1854.

Spee. Char. M. testé tenui, elongatd, obtuse cuneata vel subtrapeziformi, levigala ;
umbonibus minutis, depressis, subterminalibus ; pedi-regione brevi, contractd ; siphoni-
regione latiore, compressa ; margine dorsali recta, extensd.

Shell thin, elongated, obtusely wedge-shaped or obtusely trapeziform, smooth ;
beaks small, depressed, nearly terminal; pedal region very small and narrow ; siphonal
region broad and compressed ; dorsal margin straight and extended.

Length, 12 inch.

Localities. Bognor and Herne Bay (Hdwards).

Mr. Sowerby says, “ It is like AZ. depressa of ‘ Min. Conch.,’ but is more pointed.”

There appears also to be a little difference in outline; the dorsal margin is less curved
and more extended, and the siphonal region is rather more compressed.

16. Mopioxa suscarinata, Lamarck. ‘Tab. XII, fig. 9.

Moptora supcartnata. Lam. Ann. du Mus, t. vi, p. 222; and t. ix, pl. 17, fig. 10 a, b.
— — J. Sowerby. Min. Conch., pl. 210, fig. 1, 1818.
— _ Desh. Coq. Foss. des Env. de Par., t. i, p. 256, pl. 39, figs. 4, 5.
— — Morris. Catal. Brit. Foss., p, 212, 1854.
— — Desh. An. s. Vert. du Bassin de Par., t. ii, p. 25, 1860.
MytiLus _ D’ Archiac. Foss. du gr. numm. dans Mém. de la Soc. Géol. de
Fr., 2 sér., t. iii, pp. 433, 453, 1850.

72 EOCENE MOLLUSCA.

Spec. Char. M. testa tenui, ovato-oblongd, obliquad, gibbosd, levigatd, subcarinata,
valde inequilateralt, siphoni-regione latiore ; margine ventrali incurvatd, margine dorsali
conventusculd ; strvis accretionis notatd.

Shell thin, ovately oblong, oblique, gibbous, smooth or with visible lines of growth,
subcarinated ; very ineequilateral, with siphonal region the broader; ventral and dorsal
margins curved, but not parallel.

Length, 2 inches.

Localities. Wighgate (Wetherell), Newnham? (Prestwich).

Mr. Sowerby, in ‘ Min. Conch.’ above referred to, considers this as doubtfully identical
with the Paris basin shell, but thinks it probable it may be the same as 4/7. modiolus of
Brocchi.

In the first part of ‘ Coq. foss. des Env. de Par., t.1, p. 256, M. Deshayes has
rejected the British fossil from among his synonyms on account of its dissemblance, but
he has admitted it with a mark of doubt in his second part (Descr. des An. s. Vert., t. 2,
p. 25). Tam unable to throw any light upon this disputed point, and have therefore left
it with the name originally given by Mr. Sowerby, but I fully agree with the French author
that it cannot be united to 4. modiolus, Linn. M. Deshayes says his shell very closely
resembles an oriental species which Mr. Hanley has named J/odiola Metcalfei, except that
in the recent shell the dorsal edge is more elongated ; but it is not so in our fossil, which
bears a very strong resemblance to the Indian shell, and I think it probable the three may
be united under one name. ‘There is in the recent British species and Crag fossil,
M. modiolus, considerable variation, more so than is exhibited between the Eocene fossil
and the Indian species.

17. Moptona suucata, Lamarck. ‘Tab. XII, fig. 11.

Moproua sutcata. Lam. Ann. du Mus., t. vi, p. 222; and t. ix, pl. 17, fig. ila, 6.
— — Desh. Coq. foss. des Env. de Par., t. i, p. 258, t. 39, figs. 9, 10.
—- — Morris. Catal. Brit. Foss., p. 212, 1854.

— — Desh. An. sans Vert. du Bassin de Par., t, 11, p. 15, 1860.

Myrius suucatus. Desh. Ency. Méth. Vers., t. in, p. 566, No. 26, 1830.

Spec. Char. “ Testa clongatd, spathulatd, obliqud, depressd, antice posticeque longi-
fudinaliter sulcatd, in medio lavigatéd ; umbonibus minimis; margine antico brevissimo,
crenulato.”

Shell elongate, spathulate, oblique, depressed, both sides striated or radiated ; central
portion smooth ; umbones small; anterior margin (pedal region) very short, crenulated.

Length, ths of an inch.

Localities. Barton (Ldwards).

France, Grignon, Parnes (Deshayes).

BIVALVIA, 73

There is a single specimen only of this species in Mr. Edwards’s cabinet, and this
unfortunately is not in very perfect condition, but the figure is faithful, though a little
improved. Our shell strongly resembles the figure and description of the French fossil
above referred to, and I think it may be safely considered as belonging to that species.
A recent species has this name, but it is quite distinct. M. Deshayes says the fossil is
entitled to priority.

18. Moproxta TenvistRiata, Melleville, ‘Tab. XIII, fig. 3.

MopioLa TENUISTRIATA, Mellev. Mem. sur les Sab. Tert. Inf. du Bass. de Par. (Ann. des
Sc. Géol., 1843), p. 39, pl. 2, figs. 17-—19; and pl. 3, figs.
9, 10.

Spec. Char. M. testd ovato-ellipticd, tumidd, tenui, fragil, utroque pariter rotun-
data, pedi-regione parva; superficie omnino striata, striis tenuissimis, radiantibus ;
striis increment elevatis, decussatis.

Shell ovately elliptical, tumid or deep, thin, and fragile, equally rounded at both
extremities ; exterior wholly covered with striz; radiating lines fine and thin, decussated
by elevated lines of growth.

Length, %ths of an inch.

Locality. Barton (Ldwards).

This elegant shell is very rare as a British fossil, and of extreme tenuity. M. Melle-
ville gives two figures of his species, presenting considerable diversity of character. The
British fossil corresponds more closely with his figures § and 10, pl. ii, both in the
outline and ornament. Our shell has the umbo almost at the extremity, and very slightly
projecting. ‘The fine, radiating strize are regularly cut by lines of growth, making the shell
appear as if punctured or cancellated.

19. Moprota? tusicona, S. Mood. Tab. XIII, fig. 12, a, d.

Spec. Char. M. testé subcylindraced, levigatd, tenui, valde inequilaterah ; marginibus
dorsali et ventrali subparallelis ; pedi-regione parva, rotundatd ; siphoni-regione compressa.

Shell subcylindrical, smooth and thin; dorsal and ventral margin nearly parallel ; very
inequilateral ; pedal region small and rounded; siphonal region compressed,

Length, 3ths of an inch; height, 3th.

Locality. Whetstone?

In the museum in Jermyn Street is a specimen of the matrix of London Clay with
several tubes of the Zeredo, and located with them are two or three individuals of a
Modiola ?; these latter have apparently taken their abode in the hollow of the tubes. The

10

74 EOCENE MOLLUSCA.

specimens are unfortunately not very perfect, but a portion of the sheil is visible on one
of them; this appears to have been quite smooth and free from striz of any kind.
Assuming this cylindrical state to be the true character of the shell, it resembles that
section of the genus called Lzthodomus, but whether this form be produced from a con-
fined position it is difficult to say. Unlike the generality of the cylindrical species, the
siphonal region of our shell, if not distorted, is much compressed, and the margins are
quite closed.

This species somewhat resembles JZ angusta, Desh. (Coq. foss. des Env. de Par.,
t. I, p. 266, pl. 41, figs. 6—8), but it differs in having the umbo terminal, and our shell is
much more unequally tumid. ‘The locality is unfortunately not known.

20. Mopiona unpuuata, S. Wood. Tab. XIII, fig. 13, a, 4.

Spec. Char. M. testa tenui, depressd, elongato-cuneatd ; siphoni-regione latiore, de-
pressa ; extus levigatd, undulata.

Shell thin, depressed, elongately wedge-shaped; siphonal region broad, depressed ;
externally smooth, and undulating.

Length, 2 ches.

Localities. Harwich and Bawdsey.

There are two specimens of Septaria in the Museum of the Geological Society,
marked respectively Nos. 8290 and 15314, presented by the Rev. J. Holmes, to which
are attached the above localities ; they bear the impressions and the greater part of the
shell of a few specimens of a species of A/odiola, but in a compressed and mutilated con-
dition ; they are, however, sufficiently perfect to show, by their lines of growth, that they
most probably belonged to a species quite distinct from any other Eocene form, or at least
from any that Tam acquainted with. ‘The undulations of the exterior do not look as if
they could have been produced by compression or accident.

The entire figure (4) is a restoration.

Tab. X, fig. 5, represents the fragment of a shell which appears to belong to this genus,
and the ornamentation is so peculiar that I think it deserves to be represented in order to
call attention to its existence. It is from Highcliff, Barton, and is in Mr. Edwards’s
cabinet. he striae, or rather coste, which cover the dorsal portion of the siphonal
region, are few and very large, differing from those upon the other part of the shell, from
which character it might be called diversa. Some species have the strize of the same
magnitude all over the surface, in others the stria are smaller or narrower on the dorsal
portion of the siphonal region, and this diversity is, I think, a good mark of distinction.

CARS I

Ostrea pulchra, page 30.

Specimen from near Reading, with connexus preserved.

Mus. Edwards.

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TAB AE.

Ostrea gigantea, page 23.

a. outside view of lower valve, showing a very small mark of attachment.
Mus. Bowerbank.

6. inside view of upper or right valve. Mus. Edwards (? elephantopus).

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DAB. AIT.

Fig.

1. Ostrea Bellovacina, page 17.
a. outside view of upper valve from Charlton. Mus. Edwards.

4. outside view of lower valve

2. Ostrea cymbuléides, p. 20.
From Herne Bay. Mus. Bowerbank.

3. Ostrea prona, p. 29.

From Brockenhurst. Mus. Edwards.

A. Ostrea flabellula, p. 21.

a. outside, normal form, from Bramshaw. Mus. Edwards.
d. outside, abnormal form, from Barton. i

hi

TAB. IV.

Fic.
1. Ostrea tabulata, page 31.
a. outside view, upper valve, from Bognor. Mus. Edwards.

5. outside view, lower valve, Bf Mus. Jermyn Street.

2a. outside view of the upper valve of an oyster from Clarendon, with greatly
incurved umbo like Exogyra; supposed to be the young state of O. pulchra.
Mus. Edwards.

26. mside of another specimen, with margin denticulated near the hinge, same
locality, supposed also to be the young state of O. pulchra. Mus.

Edwards.

3. Ostrea flabellula juv.? page 21.
From Barton. Mus. Edwards.

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TAB. V.

Fie.
1. Ostrea callifera, page 18.
a. inside view of lower valve. Mus. Jermyn Street.
6. united valves, umbo inflected in a contrary direction. Mus. Edwards.

2. Ostrea adlata, p. 16.

a, 6. out and inside views of lower valve. Mus. Edwards.
ce. inside view of upper valve. Mus. Edwards.
d. inside view of lower valve, abnormal state. Mus. Edwards.

3. Ostrea marginidentata, p. 27.

a. inside view of upper valve, showing the altered form of muscle-mark.
Mus. Edwards.

d. inside view of lower valve, with normal form of muscle-mark. This
specimen had been attached by the entire outer surface. Mus.
Hdwards.

Fig

Za

——

TAB Vi;

Fic.
1. Ostrea tenera, page 31.

Specimen from Bracklesham. Mus. Edwards.

. Ostrea dorsata, p. 20.
Specimen with united valves, showing it to have been attached to some cylindrical
body, which circumstance had communicated a semi-cylindrical elevation to the
centre of both valves. Mus. Edwards.

tw

3. Ostrea multicostata P p. 28.
From Bracklesham. Mus. Edwards.

A. Ostrea longirostris, p. 26.
Specimen of lower valve, with a broad mark of adherence. This specimen has been
perforated by several stone-eating bivalves. Mus. Edwards.

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TAB. VII.

Fie.

re)

1. Ostrea velata, page 33.

6. outside view of upper valve, showing the broad strie. Mus. Edwards.

. Ostrea picta, p. 28.

Mus. Brit.

. Ostrea Bellovacina, py. 17.

a. outside view of lower valve, from Peckham. Mus. Edwards,

6. inside of upper valve, from Peckham. ‘The exterior of this specimen is free
from radiating coste. Mus. Edwards.

ec. portion of the outside of upper valve of another specimen from Peckham.

Mus. Edwards.

. Ostrea inflata? p. 26.

Mus. Edwards.

. Ostrea Vectiensis, p. 32.

a. inside view of right valve. Mus. Jermyn Street.
b. - left valve. a
(? Ostrea gryphina. Forbes.)
c. inside of upper valve of a very thick (old?) specimen, much elevated.
Mus. Jermyn Street.

(? Ostrea Sparnacensis.)

. Ostrea gryphovicina, p. 25.

a. outside view of lower valve. Mus. Wetherell.
é. inside of the lower or left valve, showing the linear hinge-area. Mus.
Bowerbank.

. Ostrea cyathula? py. 19.

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AA.

TAB. VIII.

Spondylus rarispina, page 51.
a. view of the inside of the left or free valve.
b. * outside of the same. Mus. Edwards.

. Ostrea aliena, y. 16. Mus. Edwards.

» cyathula, py. 19. *
», zonulata? p. 34. a
», flabellula (war. modicella), p. 21. Mus. Edwards.

» gigantea, p. 23. Mus. Edwards.

. Pecten Prestwichii, p. 42.

a. left valve. Mus. Bowerbank.
6. right valve. Mus. Prestwich.

The portion beyond the fracture in the right valve is made up.

. Pecten 30-radiatus ? var. 40-radiatus, p. 45. Mus. Brit.

. Pecten idoneus, p. 41. Mus. Edwards.

Pecten duplicatus, p. 41.

a. view of the outside of the right valve. Mus. Edwards.

b. - Be left valve, with imperfect ? auricles.

Edwards.

c. view of the inside of the left valve of a more elevated specimen.

Wetherell.

Pecten bellicostatus, y. 38. Mus. Edwards.

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TAB. IX.

Fia.
1. Anomia tenuistriata, page 13.

a. view of outside of the upper valve, normal form. Mus. Edwards.

b. ,, Inside of the lower valve. Mus. Edwards.
¢: ,, outside of the upper valve, with radiations. Mus. Edwards.
d. _,,__ inside of the upper valve, showing muscular impressions. Mus.

Edwards.
. specimen showing the disproportion of united valves. Mus. Edwards.

D

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. Vulsella deperdita, p. 35.

a. view of a united pair of valves of medium form. Mus. Edwards.
6. right valve of a depressed specimen. Mus. Edwards.
c. View of outside of the left valve of an elevated specimen. Mus. Jermyn

Street.
3. Pecten reconditus, p. 42.
?a. orbicular specimen from Barton, with thirty rays.
b. left valve of an elevated specimen, with eighteen rays.
c. right valve of an elevated specimen, with twenty rays.
4. Pecten 30-radiatus, p. 45.

Right and left valves, with sections of varieties.

Ort

. Pecten carinatus, p. 38. Mus. Edwards.

6. ,, squamula, p. 44. *

The two larger figures are magnified representations.

7. Pecten corneus, p. 39. Mus. Edwards.

a, c. views of the outsides of the right and left valves.
b. view of the inside of the left valve.
d. - - of specimen from Highgate (var. cor-

neolus). Mus. Edwards.

8. Pecten contubernalis, p. 40. Mus. Edwards.

a.

e¥ ith fiche ’

TAB Xx.

Fig.
1. Pinna affinis, page 55.

a. view of the left valve. Specimen from Bognor. Mus. Edwards.
c. var. intermedia. Mus. Prestwich.

2. Pinna pyriformis, y. 57. Mus, Prestwich.

3. Pecten duplicatus, p. 41.

A strongly imbricated specimen of the left valve, with perfect auricles, from
Highgate. Mus. Wetherell.

4. Ostrea zonulata, p. 34. Mus. Fisher.
5, Modiola diversa, p. 74.

Fragment of a specimen, enlarged. Mus. Edwards.

The line denotes the size of the specimen.

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TAB. XI.

Fie.
1. Avicula media, page 53.

a, d. right and left valves of an elevated specimen from Brockenhurst.
Edwards.
b, c. specimen from Barton. Mus. Edwards.

2. Avicula papyracea, p. 54.

a. view of the interior of a young? specimen from Haverstock Hill.

Edwards.
6, c. adult specimens from Highgate. Mus. Edwards.

3. Avicula arcuata, py. 53. Mus. Wetherell.

4. Lima compta, p. 48. Mus. Edwards.

5. Anomia scabrosa, p. 14. af
6. Lima expansa, p. 49. .
t. 55. Soror, p. 49. i

8. Pinna arcuata, p. 56. Mus. J. Sowerby.
9. ,, margaritacea, py. 56. Mus. Brit.
10. ,,_ ~pyriformis, y. 57. Mus. Prestwich.

The lines denote the size of the specimens.

Mus.

Mus.

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PAB. XIT.

Fie.
1. Mytilus affinis, page 61.

a, c,d. specimens from Colwell Bay. Mus. Edwards. .
6. specimen from Barton. Mus. Edwards.

2. Mytilus strigillatus, y. 61. #

3. Dreissena Brardii, p. 59.
a. view of the interior of the left valve, in which is a specimen of the arenaceous
case of a SABELLA?P

4. Modiola depressa, py. 63. Specimen from Highgate. Mus. Wetherell.

5. Modiola elegans, p. 65.
a. var. inelegans, from Highgate. Mus. Wetherell.
b. elegans, from Highgate. Mus. Wetherell.
c. var. elegantior, from Hordwell. Mus. Edwards.
6. Modiola hastata, p. 67.

Specimens from Brook. Mus, Edwards.

7. Modiola simplex, p. 71.

a. specimen from Herne Bay. Mus. Edwards.
b. a Bognor. =

8. Modiola Nystii, y. 68. Mus. Edwards.

9. Modiola subcarinata, p. 71.
Specimen from Highgate. Mus. Wetherell.

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1. Modiola semi-nuda, page 70. Mus. Edwards.

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TAB. XOE.

dorsata, py. 65. Mus. Prestwich.

tenuistriata, p. 73. Mus. Edwards.

pygmea, p. 70. eA
dimidiata, p. 64. i
eximia, p. 66. 3
Prestwichi, py. 69. 2)
nodulifera, y. 68. e
flabellula, p. 67. -

Mitchelli, py. 68. Mus. Morris.
sulcata, p. 72. Mus. Edwards.
> tubicola, y. 73. Mus. Jermyn Street.

undulata, . 74. Mus. Geol. Soc.

4. an imaginary specimen.
Deshayesu, p. 64.
dimidiata? (cast of), ». 64. Mus. Brit.

The lines denote the size of the specimens.

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