Monograph of the Palaeontographical Society

PALHONTOGRAPHICAL SOCIETY.

THE CRAG MOLLUSCA.

—_—.

Part II.
BIVALVES.

MOLLUSCA FROM THE GREAT OOLITE.

Part I.
UNIVALVES.

BRITISH
OOLITIC AND LIASIC BRACHIOPODA.
Parr III.

1850.

California Academy of Sciences

Presented byPaleontographical Society.

Decemper , 1904.

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A MONOGRAPH

OF

THE CRAG MOLLUSCA.

OR,

DESCRIPTIONS OF SHELLS

FROM THE

MIDDLE AND UPPER TERTIARIES OF THE EAST OF ENGLAND.

BY

SEARLES V. WOOD, E.G.S.

PART IT.

BIVALVES.

LONDON:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.
1850.

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A MONOGRAPH

OF THE

MOLLUSCA FROM THE CRAG.

BIVALVIA, Linneus, 1767.

Bivatvia. Bonanni, 1681. Lister, 1686. Flem. 1828.
Dituyra. Arist. Turt. 1822. Swains. 1840.
Ditoma. Tournefort, 1742.

AcEPHALA TEsTacza (part). Cuv. 1789.
LAMELLIBRANCHTIATA. De Blainv. 1814.
ConcHIFERA (part). Zam. 1818.

Concum. Leach. 1819.

Petecypopa. Goldfuss, 1820.

ENDOCEPHALA (part). Lat. 1825.
ELATOBRANCHIA. Menke, 1830.

Cormopopa. Burm. fide Herrm.

ANIMALS of this Division of the Linnean Testacea have no proper head, their most

vital parts are enveloped in a mantle, or pallium, as it is called, which surrounds them

on all sides; the edges of this mantle are sometimes plain, at others fringed, and are
more or less united: what is called the foot, is generally a large and powerful muscular
mass, capable, in some species, of being protruded beyond the shell to a considerable
distance. The respiratory organs, or dranchi@, are usually four in number, and are
arranged in the form of ruffles enveloping the abdominal mass, but entirely included
within the mantle ; in some few of the species, the number of these feathery append-
ages is less, while in others there are more, than four. The animal is protected by
two portions of shelly matter called valves, these are secreted by and formed upon the
mantle, and are articulated together by a cartilage and ligament, by which the two
pieces are held in position, and move, as it were, like a door upon its hinge, or rather
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2 MOLLUSCA FROM THE CRAG.

like the two covers of a book, this is furthermore often strengthened by prominences
and depressions in a part of the shell kept thickened for the purpose, interlocking each
other, preventing, in most instances, the possibility of any material inconvenience
arising from lateral motion without a fracture. The common action of the valves in
their separation or opening is from the relaxation of the adductor muscles, when from
the natural elasticity of the ligament the valves are drawn apart, and again closed by
the contraction of the muscle or muscles that pass from one valve to the other, strongly
adhering to the inner surface of the shell on which, in most cases, a distinct, and often
a deep indentation is left.

The muscular fibres by which the edges of the mantle are withdrawn adhere to,
and leave a linear impression somewhat within the margin of the shell; and, in some
of the Bivalvia, at the posterior side of the animal, are two siphonal tubes, formed by
the prolonged portions of the mantle, the lower one is called the inhalent, the upper
one the exhalent siphon, these tubes are capable of being protruded by the animal with
the assistance of muscles for that purpose, and again withdrawn under the protection
of the shell. In animals possessed of these tubes, the withdrawal of them is indicated
in an impression on the body of the shell by the retractor muscle, leaving what is
called a siphonal scar, or palleal sinus, which generally denotes, by its depth, a cor-
responding proportion in the length of the tubes; and where the muscular fibres of
the mantle adhere to the interior, leaving the impression without an inflection, the
animal either has no prolongation of the mantle, or that the tubes are so short as
scarcely to be capable of extension beyond the margin of the valves, and the im-
pression in that case formed by the mantle is parallel, or nearly so, to the outer edge
of the shell.

These marks, therefore, are of essential service to the Palzeontologist, as they
afford the only indications of the form possessed by the animal inhabitant, thus im-
pressed upon the interior of the valves. It is however to be feared, that a perfectly
strict reliance cannot always be placed upon the peculiar magnitude of this siphonal scar,
even in specific determination, as a marked deviation from what might otherwise be
considered its typical form may occasionally be detected, but it is in those species
which are most subject to variation in the outward forms of the shell; as a general
rule, this line, when visible, is of the greatest assistance, and at all times a good
auxiliary character in the determination of a species. The length of the siphonal
tubes, or the consequent indenture or sinuation of the mantle mark in the shell,
points out a difference in the animal from those in which the sinus is wanting, or at
least nearly so, where it indicates a mantle either without or with very short siphons,
giving fair grounds for generic separation; but occasionally, species are met with that
are otherwise very closely allied, having a similar dentition, and bear the same general
relationship in regard to the shell, although very unlike in the form of the mantle-
mark, such as Leda and Nucula, Cardium and Adacna, Lucina and Lucinopsis, and
cannot, without violence to a natural arrangement, be removed to any distant position,

BIVALVIA. 3

merely, in consequence of a difference in the length of the tubes or depth of the
sinus.”

Some Malacologists seem disposed almost entirely to reject the shell, as unworthy
of consideration in a Zoological arrangement, viewing it in the light of an inert or
morganic mass, unconnected with the animal, or at least merely formed by and used
as a protection to its more vital parts, and have based their superstructure upon the
mantle itself, and upon the difference in length of its siphonal tubes. In the ‘ History
of British Animals,’ by Dr. Fleming, published in 1828, the Bivalvia were separated
into two sections, called S1pHonipDA and ASIPHONIDA, a division subsequently
adopted by some continental authors under the denominations SINUPALEALIA and
INTEGROPALEALIA, as founded upon a portion of the animal more highly organised than
its dermal covering, and, consequently, supposed to give a more scientific basis to its
classification. Investigations by the microscope have shown a high degree of organi-
sation, and the possession of a considerable amount of vitality in the shell, essential to
the existence, depending upon, and modified by the exigencies of the animal; and in
this outer coating of the mantle there is preserved a relationship apparently more con-
stant than is exhibited by its fleshy interior; and whatever other organs, in the more
vital parts may be supposed to furnish a basis for Ordinal division, it is very doubtful
if the form of the mantle alone will be sufficient.

The number and position of those parts of the hinge called teeth are essential
distinctions, as there is a permanence of form in the dentition of all genera, although,
in a few instances, these characters which are prominent and distinctive in some
species, will be diminished and become nearly obsolete in others; but they do not
vary inform or position in the same genus.t That portion of the hinge called the
ligament, performs an important office in the animal economy, as it is by this the
valves are bound together, and kept in their true position. This uniting and elastic
substance is called cartilage, when it is placed within the edges of the valves, and is
consequently compressed when they are closed, and by its tendency to expand at the
relaxation of the adductor muscle or muscles, assists in the separation of the shells at
the ventral margins: that portion which is external, is called /2gament, and is generally
placed on a prominent fulcrum, or projecting portion of the shell, and by its elasticity
or contraction draws back and opens the valves when the opposing power of the
adductors is relaxed; although this substance is of a cartilaginous nature, and con-
tains but a small portion of lime, and is consequently not often preserved in a fossil
state, its position is always indicated where it has been, either by a pit or depression
for its reception, or by the fulcrum to which it was attached. In the smaller portion
of the Bivalvia, the animal is furnished with only one adductor muscle, and constitutes

* Great differences also exist between the mantles of some of the members of the Leptonide.
+ There is a slight exception to this rule in the hinge of the Polyodonts, Leda, Pectunculus, §c., where
the number of teeth will vary, even in individuals of the same species at different periods of existence,

but their general character is not altered.

4 MOLLUSCA FROM THE CRAG.

that division or section called Monomyaria, or Unimusculosa, by some authors. In this,
the muscle is placed in the centre, or nearly so, and is generally large and powerful,
adhering strongly to the interior, leaving often a deep indentation which is sometimes
of a different colour to the rest of the shell; the form of this muscle mark is variable
in different genera, but is not of much assistance in specific determination. Some of
these have the hinge ligament on the exterior, like the Oyster, &c., where it acts by
contraction and elongation; in others, Pecten, &c., its action is by expansion and com-
pression ; in this group, the edges of the mantle are generally disunited and not pro-
longed into siphons, and the impression formed by its muscles within the shell, is
without any inflection, and parallel to the margins of the valves. In the much larger
portion, called Dimyaria, or Bimusculosa, the animal has two distinct adductor muscles,
one of which is situated near the anterior margin, while the other occupies generally a
corresponding position on the posterior side.

As these muscular impressions are relatively situated in the same position, and
always of the same form, a great alteration takes place during the growth of the
animal by a gradual progression, as it increases in size and the shell enlarges; the
successive advancement of these impressions is indicated m many species by distinct
lines of growth: and as this enlargement necessarily increases outwardly, the animal
possesses the power of making fresh additions to the exterior portion of the muscle,
while at the interior part, the now becoming useless or inconvenient portion, is
detached from its former place of adherence, and absorbed by the animal; while in
most species, a fresh layer of calcareous matter, secreted from the whole surface of
the mantle, is deposited upon the interior of the shell, and covering the deserted
portion of the muscle mark, leaving untouched that part only against which is
attached its powerful adductor. In the Oyster, more especially, these successive
layers are distinctly visible, showmg the enlargment of the shell by the extension
of the mantle in the lines of growth upon the exterior, as also by the generally
rugose or lineated surface of the ligamental area. The same may be said of the
dental characters of the shell which are always relatively placed in regard to the
specimen, whether in the young or in the adult; and the alteration, therefore, of their
position in the growth of the shell, can only be effected by the removal of one part,
while fresh deposition is formed on the other, unless the whole be sufficiently organised
to partake of the varying changes of the animal itself: a question as yet not satis-
factorily determined.

Dr. Carpenter gives in his ‘ Report on the Microscopic Structure of Shells,’ as the
true history of the Conchiferous Acephala, the following account :—“ The margin only
of the mantle has the power of giving origin to the owfer layer of the shell, while the
whole surface may generate the imuer. very new production of shell consists of an
entire lamina of the latter substance, which lines the whole interior of the old valve,
and of a broader margin of the former which thickens its edge. So long as the
animal continues to increase in dimensions, each new exterior layer of shell projects so

BIVALVIA. 5

far beyond the preceding, that the new border composed of the outer layer, is simply
jomed on to the margin of the former one, so that the successive formations of the
outer layer scarcely underlie each other. But when the animal has arrived at its full
growth, the new lamine cease to project beyond the old, and as each is composed of
a marginal band of the external substance attached to the edge of an entire lamina of
the inner, these bands must now underlie each other, being either quite free as in
Ostrea, or closely united to each other as in Unio, and most other Bivalves; and the
additions to the shells of the Gasteropoda are made upon the same plan, although it
has commonly been supposed that they are only attached to the edge of the old shell,
instead of being continued over its entire surface.”

The figure and size of the foot materially influences the form of the anterior part
of the shell, while the posterior depends upon the modification of the siphons.
The degree of development of the nervous system is said to be very variable in
these animals, and the organs of sense dependant thereon variously distributed, im-
perfect organs of sight are present in some species, and rudimentary organs of hearing
have been detected in others, and are possibly present in all: while in some; the sexes
are separate and distinct, in others they are united or hermaphrodite, microscopic
animals and plants constitute their principal food.

Species of this class have been found in the seas of every clime, and inhabit the
waters of all depths, some few are left dry by the retiring tide, while others frequent
the bottom of seas, to the depth of 200 fathoms; and the vertical range of many
species is so extensive, as to render doubtful the allocation of strata from the presence
of a few fossil forms, with whose habits we are but indifferently acquainted; more-
over, the habits of all recent species are not, perhaps, necessarily the same as those
of their prototypes that lived in times long past, and probably, under different
conditions.

The authors of the beautiful work upon the ‘British Mollusca,’ now in the course of
publication, have given many interesting details respecting the range in depth at
which most of these animals have been obtained, and occasionally, the nature of the
ground they had selected for their habitation; the generality of species prefer clear
water and a sandy bottom, but others are frequenters of mud. The bottoms of the
Crag Seas, judging from the deposits now remaining upon the Eastern Coasts of
England, appear to have been principally of sand or gravel, with comminuted frag-
ments of shells; that of the Coralline Crag Sea being generally fine in its particles,
formed at a depth varying, perhaps, from 20 to as much as 40 fathoms, if the habits of
the then existing animals were the same as their homologues of the present day. The
Red Crag Sea appears to have been subject to greater agitation, and was probably
less in depth, while much of its bottom was of a gravelly character, or of coarser sand.
The deposits of the Mammaliferous Crag Period present us with characters rather
more variable ; that which is found near Norwich, being what is called Fluvio-marine,
formed probably, in a shallow estuary, and composed of sand, gravel, and shells,

6 MOLLUSCA FROM THE CRAG.

while the Bridlington bed was more purely marine, with a bottom apparently of sandy
mud, similar to what is exhibited by the newly discovered tranquil deposit resting
upon the Red Crag at Chillesford, where the water may have been of some con-
siderable depth.

In estimating the dimensions of the shell in the following descriptions, the pro-
portions are given only as an approximation; in most species, these are more or less
variable. The length is taken from the anterior edge of the shell to the outermost
portion of the posterior side, that being considered as anterior where the foot is pro-
truded, while the position of the ligament and the siphonal tubes, where they exist or
their presence shown in the shell by the sinuated form of the pallial impression, is on
the posterior side. Presuming, therefore, the animal to move with the foot foremost,
it will have its dorsal or hinge-part of the shell uppermost, and the diameter from the
umbo to the ventral margin is called its height, while the depth is measured from the
most tumid part of one valve to the corresponding place in the other.

Anomia.* Linn. 1767.

Anomia. Miiller. 1776.

Guycrmeris. Browne, 1756.

Lampapzs (sp.). Gevers. 1787, fide Gray.
FENESTELLA. Bolton. 1798, fide Herrmansen.
Ecuton and Ecutoperma. Poli. 1791.
Crpa. Humphries, 1797.

Anomya. dgass. 1839.

Generic Character. Shell irregular, inequivalved, subequilateral, ovate or sub-
orbicular, and fixed: lower or inferior valve more or less flattened, with a large
foramen or perforation, through which passes a bony or calcareous appendage for the
attachment of the animal; upper valve, convex smooth or irregularly laminated,
sometimes striated, costated or muricated, often assimilating the body of the shell to
that on which it is fixed; one muscular impression in the lower or fixed valve, with
three in the upper or convex one ; ligament internal, placed a little within the umbo of
the upper or larger valve, in a somewhat triangular pit, with a projection near the
edge of the foramen in the opposite valve, to which it is attached; hinge without
teeth.

The animal of this genus, is said to have the edges of the mantle disconnected,
the margins bearing a double fringe of short scirrhous appendages, without ocelli or
rudimentary eyes. No siphonal tubes, and foot very small, nearly obsolete. The
adductor muscle is divided into three parts, making three distinct impressions on the

* Etym. ’Avouows, unlike or unequal.

BIVALVIA. 7

upper, while one only is formed upon the lower valve, the other two passing into the
calcareous operculum by which it is fixed. Sexes distinct.

As the individuals of this genus are always attached, they are seldom of a regular
form, but generally more or less distorted, modified by, and often assuming the shape
and characters of the body to which they adhere; and as they are frequently attached
to the shells of the Pecten, an individual of this genus, which in its natural state is
nearly smooth, will become, in consequence, rayed or pectinated, partaking of the
characters of the body it has been living upon. If, therefore, it be attached near the
umbo of the Pecten, its regular increase will assume the form of that genus; but if its
attachment be upon the wider rays, these ribs will not represent the regular form, but
the impress of its place of attachment will be shown, as in fig. 3 4, in parallel or nearly
parallel ridges across the shell. In order to produce this appearance, the addition
that is made by the mantle to the edges of the shell are carried over the ribs of the
Pecten down into the interspaces, by which means a costated form is given to a shell,
otherwise smooth. This character, however, according to Mr. Clark, appears to be
eclectic, or at the will of the animal. Thus, whenever the under or lower valve has
its edges elevated above the ribs of the Pecten, so as not to be influenced by those
inequalities, then the upper valve retains its original form. The lower valve is
generally thin, often papyraceous, so that in the fossil state, the upper valve is
the most numerous.

The Anomia is closely allied to the Pectens, and the perforation m the lower valve,
is said by the authors of the ‘ Hist. of Brit. Mollusca,’ to be chiefly a greater extension
of the auricular sinus of that genus; and that the young fry will be probably found
attached by means of a byssus, which as the animal increases, eventually becomes
converted or transformed into the calcareous opercular process of the older shell,*this
organ of attachment being merely the extension and indurated portion of the lower
part of the adductor.

A large number of detached valves are found in the Coralline Crag, but their
specific appropriation is a matter of great difficulty from their excessive variability of
form, as well as great irregularity in their external ornament; and as their correct
assignment, even in a recent state, with “ all appliances and means to boot’ by the
aid of their animal inhabitant, as well as by assistance given in the colouring matter of
the shell, is still a doubtful matter, the appropriation of the fossil species may be looked
upon with suspicion.

Mr. Clark in the examination of this genus, has arrived at the conclusion, that
there is but one species now found in the British Seas; and that the extraordinary
variation both in form and sculpture, exhibited by individuals, is so fluctuating in
character, as not to be depended upon for specific distinction. As, however, there
are generally some marked differences in these shells by which the variations may be
separated, I have followed the authors of ‘British Mollusca,’ in considering them for
the present so many distinct species.

8 MOLLUSCA FROM THE CRAG.

This genus is found in the Secondary Rocks; one species has been described by
Mr. Bean, from the Cornbrash ; ‘ Mag. Nat. Hist.’ 1839. And some from the Green-

sand by Dr. Fitton.

1. ANomIA EPHIPIUM, Linneus. Tab. I, fig. 3, a—d. ,
Anom1A EPuIpriuM. Linn. Syst. Nat. ed. 12, p. 1150, No. 218, 1767.
— squamuLa. Id. - - - p. 1151, No. 221.
sox Turt. Brit. Biv. p. 229, pl. 18, fig. 5-7, 1822.
— — Broce. Conch. Foss. Subap., p. 461, 1814.
a Dekay. Nat. Hist. New York (Zool.), p. 168, pl. 12, fig. 209, 1843.
— — Middendorff. Malacozoologia Rossica (Mem. de lAcad. des Sc. Imp:
de St. Petersb.), p. 519, t. 11, fig. 18-21, 1849.
— sutcaTa. Poli. Test. Sic. vol. ii, p. 186, t. 30, fig. 12.
—~ _ MARGARITACEA. Id. - - t. 30, fig. 11.
~ C@PA. Id. - - - t. 36, figs. 1, 25-8.
— wrens? Goldf. Pet. vol. ii, p. 40, t. 88, fig. 8, a—e.
— eEpuHippium. S. Wood. Catalogue, 1840.
— costata. Broc. Conch. Foss. Subap., p. 463, t. 10, fig. 9, 1814.
— aprata?-— Id. - - - = t, 10, Be. 10,
— suteata? Id. - - - = *t. 10, fig. 12,

Spec. Char. Testé polymorpha, crassd vel tenui, plerumque lavigatd, forma valde

arregulart.

Shell many shaped, thick and strong, sometimes thin and fragile, generally smooth,
form very irregular.

Diameter, ths of an inch.

Locality, Cor. Crag, Sutton, Sudbourn.

; Recent, Mediterranean, Britain, Scandinavia, North America.

The variety of this species, called sgvamula, is exceeding abundant in the Coralline
Crag, and like the recent shell, is subject to great distortion, depending upon the
body to which it has been attached; a large number of these specimens have taken the
characters of the genus Pecten, to which, in the living state they were attached, but it
is only in the upper or free valve that I have been able to observe the costated form, the
lower or adherent one was probably much thinner, and less capable of preservation.

A few specimens of the lower or perforated valve are occasionally met with, and in
all that I have seen, the valve is externally smooth, at least, free from striz or coste,
and its place of attachment was some smooth or even surface. This variety does not
appear to have attained the size of more than 3ths of an inch in diameter, and the
majority of specimens have not reached above half those dimensions. In those
which have the upper valve quite flat and smooth, the place of attachment was
probably the mterior of some shell, from which the lower valve would take the
convex form, giving room between the two for the occupation of its inhabitant. The
beak or umbo of this species, is almost immediately at the margin or projecting a
little beyond it.

BIVALVIA. 9

The variety called cylindrica or cymbiformus (fig. 3, ¢), is also occasionally found in
the Coralline Crag, though by no means abundantly. It has been determined by
British Conchologists, that this form is produced from its place of adherence being the
stem of the seaweed, or some such cylindrical body,* while the variety /foruicata
is said to be merely a deformity from some similar cause; this I have not yet seen
in the fossil state. The exterior of some of the Crag specimens indicate their place
of rest to have been upon a Bryozoon, the shell being prettily and distinctly marked by
that animal. .

Some idea may be formed of the Protean character of this species, as no less than
eighteen different specific names are introduced by the authors of the ‘ Hist. of Brit.
Moll.’ into their synonyma, while these, with several others by them, considered
as distinct, are included as mere varieties by Mr. Clark.

2. ANOMIA ACULEATA, JMiiller. Tab. I, fig. 2, a—dé.
Anomia acuLEaTA. Mill. Zool. Dan. Prod., p. 249, 1766.
— — Mont. Test. Brit., p. 157, pl. 4, fig. 5, 1803.
== —_ Brown. Brit. Conch. Illust., pl. 34, fig. 6, 1827.
_ — S. Wood. Catalogue, 1840.
= — Gould. Invert. Massach., p. 139, fig. 90, 1841.
—_ —_ Philippi. En, Moll. Sc., vol. ii, p. 214, t. 28, fig. 1, 1841.
a= — Thorpe. Brit. Mar. Conch., p. 123, fig. 73, 1844.
= — Loven. Ind. Moll. Scand., p. 30.
— — Dekay. Nat. Hist. New York (Zool.), p. 168, pl. 12, fig. 210.
— sTrIoLaATA. Turt. Brit. Biv., p. 233, 1822.
— — W. Wood. Ind. Test., p. 54, pl. 11, fig. 7, 1825.
ae = Flem. Brit. An., p. 396, 1828.
— — Thorpe. Brit. Mar. Conch., p. 123, 1844.

Spec. Char. Testé suborbiculari vel ovata ; striata, striis plurimum numerosis, radian-
tibus, squamoso-aculeatis ; umbone submarginali, levi.

Shell suborbicular or ovate ; striated, strize generally numerous, with fine elevated
or squamose prominences, rendering the surface rough or prickly ; umbo, submarginal,
and smooth.

Diameter, 4 an inch.

Locality. Cor. Crag, Sutton, and Ramsholt.

Recent, Mediterranean, Britain, Scandinavia, and North America.

This species, called the prickly Anomia, is very abundant in the Coralline Crag at
Sutton, whence all my numerous specimens were obtained. - I have not yet seen it
from the newer formations. It closely resembles the young of the preceding in most

* This, however, was not the position of our shell, which is the upper or imperforate valve, and is
quite flat, the lower or adherent one, was probably convex externally, and fixed to the interior of some

cylindrical body, and to which our specimen must have acted as a lid.

2

10 MOLLUSCA FROM THE CRAG.

of its characters, but may be distinguished, if not specifically, certainly as a variety,
by its sculpture, which is in the form of spinous or squamose radiations. In the
recent state, the lower or perforated valve, is said to be generally thin and fragile, and
destitute of the aculeated striz. As the shells found in the Crag are separated or
detached, they would not be recognised, if this were always the case; but many of the
lower valves are alike ornamented with these markings, though they are less con-
spicuously so than upon the upper ones. The umbo of this is placed very near the
margin, and is generally slightly recurved; the strie are numerous, although in
some specimens they are more distant; but im all they have more or less, the
vaulted or raised, and slightly reflected edges, which as it grows produce the
series of aculeated or fimbriated striz upon the exterior, though very faintly
exhibited in the variety called strio/ata. In the very young of some of my speci-
mens, the shell appears to be free from sculpture of any kind, and this may favour the
opinion of Mr. Clark.

3. ANOMIA PATELLIFORMIS, Linneus. Tab. I, fig. 4, a—é.
ANOMIA PATELLIFORMIS. Linn. Nov. Act. Upsal., vol. i, p. 42, pl. 5, figs. 6, 7, 1773.
a — Loven. Ind. Moll. Scandin., p. 30, 1846.
ae — Alder, Cat. Moll. North. and Durh., p. 75, 1848.
= — Forb. and Hani. Hist. of Brit. Moll., vol. ii, p. 334, pl. 56,
figs. 5, 6, 1849.
— — Middendorf. Malac. Ross. (Mem. de l’Acad. des Se. St. Petersb.),
p- 521, 1849.
— UNDULATIM sTRIATA. Chem. Conch. Cab., t. vili, p. 88, tab. 77, fig. 699.
— unpuLATA. Gmel. Syst. Nat., p. 33, 46.
i _ Mont. Test. Brit., p. 157, pl. 4, fig. 6, 1803.
— — Turt. Brit. Biv., p. 230, pl. 18, figs. 8, 9, 10, 1822.
— _— Brown. (lust. Conch. Gr. Brit., pl. 34, figs. 2, 3, 1827.
—- — Flem. Brit. An., p. 395, 1828.
a — S. Wood. Catalogue, 1840.
Ostrnum sTRiatuM. Dacosta. Brit. Conch., p. 162, pl. 11, fig. 4.
OsTREA sTRIATA. Donov. Brit. Shells, vol. ii, tab. 45, 1801.
— — Mont. Test. Brit., pp. 153, 580, 1803.
— = List. Hist. Conch., fig. 36.
Ency. Meth., pl. 171, fig. 16, and pl. 184, figs. 5, 6.

Spec. Char. Testa suborbiculari, plicis 20—30 conveais, undulati-radiatis ; striis
concentricis crebris, sublaminacers ; umbone subprominulo a margine remotiusculo. |

Shell suborbicular, ornamented with 20—30 radiating and undulating ribs; con-
centric strize or lines of growth thick and sublaminated; umbo slightly prominent,
a little distant from the margin.

Diameter, 14 inch.

Locality. Cor. Crag, Sudbourn and Sutton.

Red Crag, Sutton, Bawdsey, Walton Naze.
Recent, Britain and Scandinavia.

BIVALVIA. 1]

A few specimens resembling the figure, and corresponding with the description of
what the authors of ‘ Brit. Moll.’ have considered as distinct, are in my cabinet, from
the Coralline Crag: they consist of the upper valve only, which is somewhat finely
striated over the earlier formed part of the shell, while the latter or outer portion is
covered with larger and coarser radiations. The umbo is rather more prominent, and
placed at a greater distance from the margin than in Aphippium, a broad triangular
fossette beneath the umbo received the ligament, and the upper valve in my Cor. Crag
specimens is nearly flat. A number of specimens of the upper valve, from the
Red Crag, present characters by which they may be referred to the above recent
species, and are uniform in their exterior markings, having large and undulating ribs
or broad and elevated strie (fig. 4, @). This is the only species or variety, that I have
been able to obtain from the Red Crag, and those specimens, as might be expected, in
that deposit, consist of the upper or thicker valve only; this is pretty uniform in
shape, which is nearly orbicular, though the diameter insome is greater from the
umbo to the ventral margin, in others it is the reverse.

4. ANOMIA STRIATA? Brocchi, Tab. I, fig. 3.
Seuama MaGNa? Chem. Conch. Cab., t. vii, p. 87, pl. 77, fig. 697.
Anomia stTRIATA? Broce. Conch. Foss. Subap., p. 471, t. 10, fig. 13, 1814.
— — ? Loven. Ind. Moll. Scand., p. 29.
— — ? Goldf. Pet. Germ., t. ii, p. 39, tav. 88, fig. 4, a—e.
_ — Phil. En. Moll. Sic., vol. ii, p- 66, 1844.
— — ? Forb. and Hanl. Hist. Brit. Moll., vol. i, p. 336, pl. 55, figs. 1, 6, and
pl. 53, fig. 6, 1849.
— ruGosa. Myst. Coq. Foss. de Belg., p. 312, pl. 24, fig. 6, 1844.
— seuama? W. Wood. Ind. Test., p. 55, pl. 11, fig. 11, 1825.
— — ? Brocchi. Conch. Foss. Subap., p. 462, No. 4, 1817.
? Ency. Meth., pl. 171, fig. 22.

Spec. Char. Testd variabile, orbiculata, vel transverse ovata, discoided, radiata ; striis
creberrimis, imbricato-squamulatis ; umbone submarginalt.

Shell variable, ovate, orbicular or discoidal ; sometimes transversely ovate, covered
with numerous radiating, rather rough or imbricated striz ; umbo submarginal.

Diameter, 2 inches.

Locality. Cor. Crag, Sutton, Sudbourn, and Gedgrave.

Recent, Britam and Scandinavia.

A large number of loose valves in my cabinet, from the Coralline Crag, correspond
with the figures and description as given of the recent shell under this name, which is,
probably, the same as the fossil one figured by Brocchi, although that shell appears to
have the umbo rather nearer to the margin. Ours may be described as variable in
form, the upper valve sometimes flat, in others convex, covered over with numerous
subimbricated strize, with the umbo a little distant from the edge.

12 MOLLUSCA FROM THE CRAG.

Anomia striata, J. Sow., Min. Conch., t. 425, differs from our shell, in having more
numerous and much finer strize without the roughness of the Crag specimens, and is in
all probability distinct; the umbo of the Eocene shell extends to the edge, or very
nearly so, and was, probably, not so thick in substance.

These, as before remarked, have been separated into different species by recent
Conchologists, but their correct specific distinction cannot be expected in fossils,
when the recent forms are so perplexing as to defy determination, or at least to pro-
duce great diversity of opinion; it is, therefore, only attempted with the Crag species,
to assign them to what is believed to be identity of form or correspondence with those
shells which are found in recent seas.

OstREA, Linn. 1758.*

OstrEA. Lister, 1686.

OstrmA. Defrance. Swains. Reeve and Catlow.
Ostreum. Rumph.1705. Adanson, 1757.
Mya. Scopoli, 1777,

PELoRIS and PELORIDERMA. Poli. 1791.
DenpostRmsa. Swains. 1840.

Gen. Char. Shell attached by a part of the larger or lower valve, generally thick
and strong, lamellated or foliated, variously shaped, irregular, inequivalved, inequi-
lateral; upper or free valve flat or slightly concave; under or adherent one convex,
sometimes strongly marked with radiating, lamellated coste; hinge without teeth,
ligament lodged in a linear depression in each valve semiexternal. Impression
of the adductor muscle, large subcentral, that by the mantle entire, generally indis-
tinct, and ill defined.

The animal has the mantle disunited on all sides, with its edges bordered by
short tentacular fringes ; foot obsolete. Sexes distinct.

The shells of this genus have only one muscular impression, which is always a little
inclined to the posterior side. These animals fix themselves by the exterior of the
left valve, and the space upon the shell denoting the place of adherence is exceedingly
variable in size, depending, probably, upon external causes; in some individuals, the
greater part of the entire surface is employed, while in others, this place of attachment
is scarcely to be discerned, and occupies only a small portion of the pointed umbo of
the shell. The ligament may be considered as external, separating the valves by its
contraction when the adductor is relaxed. This ligament takes its rise at the extreme

* Etym. darpeoy, a fish, (ooreor) ?

BIVALVIA. 13

poimt or umbo of the shell, and advances with the increase of the animal, apparently
in an opposite direction to that of the Dimyaria, the additions being made in a some-
what sloping, direction inclining towards the anterior side, the successive advance is
denoted by the lines of increase, as the fresh layers of calcareous matter are deposited
by the animal, most distinctly visible in this ligamental area, which may be called
tripartite.

The general substance of the shells of this genus is thick, though they are ex-
ceedingly variable in that character, some specimens of the common Oyster possess a
solidity of nearly an inch, while others, quite as large, have not a fourth of that
thickness.

This is a Marine genus, though many are inhabitants of estuaries, and some will
live where the water, at low tide, is not very salt. Its presence, in any formation, is
considered to be indicative of its marine nature; none have yet been found as true
inhabitants of freshwater. It is a genus of great antiquity, species having been
figured from various secondary formations from the lias to the chalk, while some
were natives of the Seas during the Eocene Period, all of which have become extinct.

1. OstREA EDULIS, Linneus. Tab. I, fig. 1, a—e.

OstreA. Lister. Hist. Conch., lib. iii, fig. 30, A, and fig. 31, 1687.
— Knorr. Delices des Yeux, pl. 24**, fig. 2, and pl. 25**, fig. 2, 1766.
— spuuis. Linn. Syst. Nat., ed. 12, p. 1148, No. 211, 1767.
— _ Poli. Test. Sicil., vol. ii, p. 169, t. 29, fig. 1, 1795.
= — Mont. Test. Brit., p. 151, 1803.
— — Broce. Conch. Foss. Subap., p. 562, 1814.
— — G. B. Sowerby. Genera, No. 6, fig. 1.
— — De Blaimv. Man. Malac., pl. 60, fig. 1, 1825.
— — Crouch. Int. Lam. Conch., pl. 12, fig. 8, 1827.
— — Goldf. Pet. Germ., vol. ii, p. 19, t. 78, fig. 4, a—h.
— a S. Wood. Catalogue, 1840.
= — G. Sow., Jr. Conch. Man., fig. 180, 1842.
= = Phil. En. Moll. Sic., vol. i, p. 90; vol. ii, p. 64.
— — Nyst. Conch. Foss. de Belge, p. 327, pl. 31, fig. 2, a, 6, and pl. 33,

fig. 2, a’, 6’, 1844.
= — Loven. Ind. Moll. Scand., p. 30, 1846.
aoe — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 307, pl. 54, and pl. T,
fig. 1, 1850.

— psEuDO-EDULIS? Desh. Exp. Sc. de. Morée, p. 231, pl. 5, figs. 3, 4.
— opeEFoRMIS. Parkinson. Org. Rem., vol. ii, pl. 14, fig. 3, 1811.
== _ Desh. 2d ed. Lam., tom. vii, p. 229, 1835.
— urprorus. Desh. 2d ed. Lam., tom. vu, p. 219, 1835.
— Bosiayzi? Desh. Exped. Scient. de Morea, pl. 3, figs. 6, 7, 1833.
— parasitica. Turt. Brit. Biv., p. 204, pl. 17, figs. 6, 7, 1822.
— — Flem. Brit. An., p. 392, 1828.
— — Thorpe. Brit. Mar. Conch., p. 120, fig. 108, 1844.
— peEnticuLATA’ Born. Mus, Cees. Vindobon., p. 113, t. 6, figs. 9, 10, 1780.

14 ‘ MOLLUSCA FROM THE CRAG.

OstrEA DENTICULATA. Desh. 2d ed. Lam., tom. vii, p. 225.
= — Broc. Conch. Foss. Subap., p. 568, 1814.
— otrosa. Broce. Conch. Foss. Subap., p. 563, 1814.
— unevtata. Nyst. Coq. Foss. de Belg., p. 325, pl. 24, fig. 8; pl’ 26, fig. 8; and
pl. 34, fig. 1, a, a, 6, 1844.
— pornatis? Desh. 2d ed. Lam., tom. vii, p. 220.
_— _ Gould. Iny. Massach., p. 137, 1841.
— spectrum. (Leathes, M.S.) Woodward Synop. Tab. Brit. Org. Rem., p. 20, 1830.
— — S. Wood. Catalogue, 1840.
— uLaMELLOsA. Goldf. Pet. Germ., vol. ii, p 18, t. 78, fig. 3, a, 6.
OsTREUM VULGARE. Dacosta. Brit. Conch., p. 154, pl. 11, fig. 6, 1778.
AURICULARIA MAXIMA. Dale. Hist. and Antiq. of Harwich, p. 291, t. xii, fig. 2, 1730.
Ency. Method., pl. 183, figs. 3, 4? pl..184, figs. 7, 8.

Spec. Char. Testé variabile, plerumque ovato-rotundatd, basi subattenuatd, concen-
trice lamellosd, interdum radiato-costatd, costis imbricatis, undulatis ; valvd superiori
plana.

Shell variable, for the most part of a roundedly ovate form; base of the shell,
slightly attenuated, concentrically lamellated, sometimes costated with imbricated and
undulated ribs ; upper valve flat.

Diameter, 3 ches.

Locality. Cor. Crag, Ramsholt, Sudbourn, Gedgrave.

Red Crag, Passim.
Recent, Britain. North America? Mediterranean ?

The earliest appearance of the true edible Oyster seems to have been in the
Coralline Crag Period, so far as it is possible to determine a species in this truly
variable genus, and its diversified forms were then as great as we see them in the
recent shell of the present seas. In the same deposit, at Ramsholt, and.in the same
bed in close proximity, are two very distinct varieties, from which, as well as from a
great dissimilarity of form, solidity of shell, and other differences, it was presumed at
the time my Catalogue was drawn up, that they were specifically distinct; but the
variety then considered different, and which passed under the provisional name of
spectrum, corresponds with the recent shell that is now determined by British Con-
chologists to be only a local variation, and they are, therefore, here united into one
species. At Ramsholt there is a complete bed of this shell (parasitica), sometimes
attached to each other in clusters, or often to the large species of Balanus, so abun-
dant in that locality ; at this place, also, the thick and ponderous variety (fig. 1, @), is
occasionally met with, but not in any great profusion; the latter shell is at this place
more isolated in its habits and regular in form, and is sometimes marked with nearly
obsolete radiating costee, with a very rugose exterior to the lower or adherent valve,
while in the upper valve there are no markings, except the regular lines of growth ;
in the other variety, there is less appearance of the radiating ribs with a more
lamellated exterior, and the shell is much thinner, and less regular in shape, partaking

BIVALVIA. 15

of irregularities produced by its often confined position, the edges of the lower valve
of this variety have sometimes a fimbriated character, like what has been called
denticulata, parts of the larger valve projecting considerably beyond the upper, more
especially on each side of the hinge, where the shelly matter is pushed up or elevated,
so as to have, in some specimens, the fanciful resemblance to a spectral appearance
produced by a person with extended arms beneath a cloth, which suggested the name
to the late Rev. G. R. Leathes. The more common variety of the present day, and the
one by which our markets are supplied, does not appear in this deposit, at least, there
is nO specimen in my cabinet strictly resembling that shell, although there is no doubt
the specimens figured are mere modifications of the same species.

A detailed description of this common and well-known shell is unnecessary, as the
form and appearance of almost every specimen will present some diversity. It may,
however, be observed, that in the interior of the upper valve of some specimens of
the thick variety, a little within the hinge, is a small indentation or puncture not
present in all, and may be often seen in the common variety of the recent shell: for
what purpose this is intended or how produced Malacologists have not informed us, as
it appears to have been overlooked, probably, as of no importance ; it certainly is of no
use as a specific determination, as the same may be seen in specimens of a very dif-
ferent species from the deposits of the older Tertiaries. The form of the impression pro-
duced by the adhesion of the adductor muscle, it is to be feared, is a character of no
ereat dependence, assuming, as it often does, a variation in shape conforming, in some
slight degree, to the outward form or contour of the shell: in the thick variety, this is
generally more or less ovate, its longer axis being from the anterior to the posterior
side, and slightly contracted in the middle of the upper part, ascending and some-
what pointed towards the posterior; rounded on the lower side, and rather broader
on the anterior, or towards the middle of the shell; in the var. spectrum, or para-
sitica, this mark is as broad as it is long, and of nearly an orbicular or roundedly
quadrate form.

A long and interesting history of this species, and of its commercial value, is given
by the authors of the ‘Hist. of Brit. Moll., who consider the English coast as its
peculiar province, and although it has a very considerable geographical range, it is
nowhere obtained in such great perfection as in our own seas; there is not in
that work any notice of this shell, as an inhabitant of the Mediterranean Sea, and it is
certainly not given as a living species by Philippi in his ‘En. Moll. Sic.,’ nor by
Payraudeau in his ‘Catalogue of Corsican Shells ;’ but in Poli’s splendid work ‘ Test.
utrius. Sicil. 1795,’ is figured and described a group of shells, as well as the animal, of
what appears to belong to this species, and from the general accuracy of that obser-
vant author, there is very little doubt the specimens were procured in those seas.
From the List of Synonymes, it will be seen, that several authors have given this as a
fossil from the newer Tertiary formations of that part of the world, where it has been
considered by many to be no longer in existence; and the fossil from the Morea,

16 MOLLUSCA FROM THE CRAG.

described by Deshayes as a new species, under the name of O. Bodlayer, does not
appear from the representation to be more than a modified form of our very variable
shell ; and for my own part, I am much inclined to believe, that Poli was correct, and
that it is still an inhabitant of the Mediterranean, as a specimen evidently of this
species was lately shown to me by Professor E. Forbes, said to have been obtained
by Mr. M‘Andrew, very near to Gibraltar. The common Oyster of North America,
called 0. dorealis, by Lamarck, which differs very materially in its varieties, is still con-
sidered by some Conchologists as doubtfully distinct. Dr. Gould says, ‘ Invert.
Massach.,’ p. 138, “ The Oystermen maintain that our shell is identical with the English
Ost. edulis, and there are certainly forms m which the American and European speci-
mens could not be distinguished ;’’ and although this is described by that gentleman
under the name of doreals, it was evidently his impression also, that it was not
specifically distinct, as Ost. edulis, Linn. is enumerated in his synonyma. A fossil
species, also, from the upper Tertiaries of America, figured and described by Conrad
under another name, so strongly resembles our species, as to excite suspicion that it is
not really different. It is, however, exceedingly difficult in this, perhaps, more so
than in most others, to determine its specific limitation, and every species in this
genus seems to possess the character of deviating in a great degree from what
might be called its typical form. Sir Charles Lyell, in his ‘Second Tour to the
United States,’ vol. i, p. 312, speaks of the Virginian oyster (Ost. Virginica), as
resembling the British shell, when it lives isolated and grows freely under water, but
that it loses this more rounded form, and becomes greatly lengthened, when living
gregariously on banks between high and low water-mark. Our own oyster will
assume a variety of forms, dependent principally upon its peculiar position, but no
amount of confinement or lateral pressure will train it into the elongated shape of the
Virginian shell.

I believe, however, the range of this species in the living state may be said to
extend from the Mediterranean to the North-Eastern Coast of the United States,
although it appears to have selected, for its more favoured abode at the present day,
the seas of our own Island.

The portions of the formation belonging to the Mammaliferous Crag Period have
not, to my researches, yielded this species, nor is it enumerated as amongst the Estnary
shells of the Norfolk Beds, by Woodward.

BIVALVIA. KA

2. OsTREA PRINCEPS, S. Wood. Tab. I, fig. 1, a—é, and Tab. II, fig. 2, a—4é.
OsTREA UNDULATA. Nyst. Coq. Foss. de Belg., p. 324, pl. 24, fig. 7 a, and pl. 26, fig. 7 4,
1844, (not J. Sowerby).

Spec. Char. Testé magnd, crassd, rotundatd ; valvd sinistrd convexd, costatd, costis
aumerosis elevatis, radiantibus, divaricatis, concentricé undato-plicatis; valvd superiori pland,
obsolete costatd.

Shell large, thick, and rounded; left or lower valve convex, ornamented with
numerous, elevated, radiating and bifurcating coste, lines of growth or concentric
laminz of an undulate or waving form, slightly reflected over the ribs; upper valve
flat, with faint depressed, or nearly obsolete rays.

Diameter, five inches.

Locality, Cor. Crag, Sutton, Ramsholt, and Sudbourn.

Red Crag, Sutton, Newbourn, and Bawdsey.

This elegant shell was obtained by my friend, W. Whincopp, Esq., of Woodbridge,
who has kindly permitted me to have it figured; a similar specimen, though not quite
im so great perfection, is in the handsome museum recently erected by the liberal
inhabitants of the town of Ipswich; two or three more of the same dimensions are in
the possession of E. Acton, Esq., of Grundisburgh, and these with another in the
Cabinet of J. S. Bowerbank, Esq., constitute the whole that I have seen of that
magnitude.

Such specimens appear to be very rare, as it was never my lot to find so large a
one during my researches in the Crag of Suffolk, although the same shell, in its
younger state (fig. 2 4), has been for many years in my cabinet, and from its presenting
characters in that condition, by no means distinct, it was considered only as a variety
of edulis, but the deeply sculptured markings, so well displayed in the specimen
figured, seem to justify its beimg considered as a different species, although it
must be confessed, the gradations of alteration between the young of this, and some
of the varieties of the common edible species, are so trifling, that the line of
separation cannot satisfactorily be pomted out. There are, in this genus particularly,
perplexities in specific determination, so that no diagnosis can be given of any one
species that is not liable to serious deviation, and the present name is assigned
provisionally, from the apparently marked difference in the adult state, and which, if
it be not specifically distinct, its elegance, a rather uncommon character in this genus,
will entitle it to be ranked as a marked and peculiar variation, worthy of a dis-
tinguishing appellation.

A slightly sinuated form is visible on the posterior side, where the costz also
appear more particularly to have a divaricating character. Upon the young shell the
radiating ridges or coste are but few in number, and by no means prominent or
distinct, appearing then strongly to resemble the edu/is ; as it enlarges, the differences
become more visible, the rays being prominent and regular. The edge or inner margin
of the shell is deeply indented with a slightly reflected edge, thus producing the sub-

3

18 MOLLUSCA FROM THE CRAG.

lamellated costz of the exterior. One peculiarity, observable in this shell, is the very
small portion of surface by which it was attached, its own substance and weight
seeming sufficient security against displacement by the movement of the water.

The form of its muscular impression is elongato-ovate across the shell, differing in
no respect in that character from the form displayed by the same muscle in specimens
undoubtedly belonging to edulis. The upper valve is quite flat, very thick, and only
faintly marked with radiations, scarcely visible in the younger state, and on each side
of the ligamental area, upon the edge of the shell, are some denticulations like those
visible upon the same valve of edu/is in the same place.

Hinnites.* De France, 1821.

Hinnita. Ferussac. 1821. Gray, 1826.
Hinnitrs. J. Sow. 1827.

Hinnus. J. Sow. 1835.

Hynnites. Herrn. 1846.

Generic Character. Shell inequivalve, subequilateral, more or less ovate, thick, and
strong, covered externally with somewhat irregular, squamose, or radiating coste.
Valves eared with a deep and elongated area for the ligament or cartilage, which is
wholly internal; a large ovate impression by the adductor muscle, that by the mantle
entire.

ANIMAL UNKNOWN.

This genus was first established by M. de France, in the ‘Dict. des Sci. Nat.,’
tom. xxi, p. 169, upon a fossil species, which appeared to unite the characters of the
two genera, Ostrea and Pecten, differing from the former in adhering by its outer
surface, only in its older state, and by the opposite valve: while in the young it was
probably fixed by a byssus. It has, by some authors, been united with Pecten since one
species of that genus (P. pusio), is in the young state fixed by a byssus, but when more
grown, becomes attached by the outer surface of its right valve in the same manner.
This peculiar habit is here considered as alone insufficient for excluding the present
genus, as the extreme solidity of two or three fossil species of typical characters, with
a peculiar form in the muscle mark, seem to indicate a difference in the animal
inhabitant sufficient to remove them from Pecten.

In the juvenile state the form of the shell is very similar to that of Pecten with
its projecting auricles, and an opening or sinus beneath the anterior one in the right
valve through which, in all probability, there issued a byssus; as it advanced in age
its habits became altered, when it fixed itself by the outer surface of its valve. This
same habit is adopted by P. pusio in the recent state, though not so in the fossil form
of what is considered as the same species in the Crag Formations, where they never

* Etym. iyvos, hinnus, vel vyros, vomer, sec, Herrm.

BIVALVIA. 19

became attached by the exterior of the shell, but always preserve their regularity or
partial freedom. The exterior of the shells in this Genus have not the regularly
radiating form of striz or costa, so characteristic of the Pectens or fans, but they are
ornamented with arched or lamellated fringes or squamose appendages, more re-
sembling the exterior of Spondylus, to which they appear to have considerable affinity,
and, indeed, may be considered as a connecting link between Ostrea and that Genus,
differing from the former in having distinct auricles in the young state, and in adhering
by a different valve; and from the latter, in the absence of those dental characters
prominently exhibited in Spondylus.

A few species only are at present known, and those all in a fossil state ; two or
three are peculiar to the Tertiary Formations, and one has been figured by Mr. Sowerby
in ‘ Min. Conch.,’ from the Inferior Oolite of this country.

1. Hinnites Cortesyi, De France. Tab. III.
Hinnires Cortesyi. De France. Dict. des Sci. Nat., t. 21, Art. Hinnites, p. 169, Atlas,
fig. 1, la, 1821.

— _— De Blainv. Malac., pl. 61, fig. 1, 1825.
— — Desh. 2d edit. Lam., tom. vii, p. 150, 1836.
_ — Chenu. Ill. Conch. Hinnites, pl. 1, fig. 4.
— Corrzstanus. De Blainville. Dic. des Sci. Nat., t. 32, 311, 1824.
— Dvsuisson1. J. Sowerby. Min. Conch., t. 601, 1829.
— — Woodward. Syn. Tab. of Org. Rem., p. 20, 1830.
— — Id. Geol. of Norf., p. 44, 1833.

Hinnus Dusurssont. J. Sow. Syst. Ind. to Min. Conch., p. 244, 1835.
— — S. Wood. Catalogue, 1840.
— — J. Morris. Catal. Brit. Foss., p. 110, 1843.

Spec. Char. Testé magnd, ovata, depressd, crassd, radiatim et undulatim costatd ;
transversim squamoso-lamellosd ; auricults inequalibus ; sulco cardinal, prelongo, et profundo.
Shell large, ovate, depressed, thick, and strong, with radiating and undulating coste ;
ribs covered with squamose projecting lamellz; auricles unequal; and a deep and
elongated sulcus for the ligament.

Length, 5 inches. Hezght, 6 inches.

Locality, Cor. Crag, Ramsholt.

Although a shell of great strength and solidity, it is by no means abundant as a
British fossil, and I have seen it only from one locality, and that in the Coralline Crag.
The specimen now figured was from a less disturbed part of that deposit, where the
two valves of many of the Bivalvia are found in their natural position; while the one
figured in ‘Min. Conch.’ was from a single valve. A few other specimens were
obtained by W. Colchester, Esq., from the same spot, and these constitute all that
I have as yet seen.

A perfect representation of the Genus Pecten is exhibited in the young shell, and
it must then have been difficult to have pointed out a character by which it could be

20 MOLLUSCA FROM THE CRAG.

considered as belonging to any other; there is, however, even in that state an irregu-
larity in the arrangement of the rays, which are at rather unequal distances, and have
indications of the squamz that so prominently ornament the adult shell.

When full grown its true characters are displayed, and no mistake can, I think,
then arise respecting its generic distinction from that of Pecten. Our shell is nearly
of an oval form, having its height or diameter from the umbo to the ventral margin,
one sixth more than in a contrary direction. The lower or adherent valve is rather
the deeper of the two, while the upper or left valve is nearly flat; the latter is orna-
mented with numerous undulating rays at somewhat irregular distances, amounting
to as many as forty in one specimen, and these are elevated and arched at different
periods of growth, giving a roughened file-like appearance to the exterior ; on the other
valve the rays are fewer, less regular, and the imbricated squamose appendages larger
and more prominent, resembling in that character the common Oyster. The hinge-line
in the adult shell is nearly straight, having an elongated and deep sulcus for the
ligament, enlarging downwards, and slightly visible externally at the umbo; this is
placed a little on the posterior side of the centre, giving a slight mequality to the
auricles, the anterior one being of course the larger ; the muscle mark is of an enor-
mous size, occupying nearly half the length of the shell, while the diameter of it in the
other direction is rather less. ;

In assigning the Crag shell to H. Dubuissoni, Mr. J. Sowerby says he was guided
to that determination by the description only, and having seen but one valve, thought
the comparison suited better with the shell from the older Tertiaries than with the
other species described by M. De France. I regret exceedingly not having been able to
obtain, for comparison, a specimen of either of the two species described by M. De France,
and the dependence here is also based upon an insecure foundation. I feel, however,
more disposed to refer our shell to /. Cortesyi, as well from what appears a greater
correspondence in their external characters having both valves for our guidance, as
also from the age of the formations in which they were obtained ; and as no new name

is imposed, the simple alteration is a matter of no great importance should it hereafter
be found to be erroneous.

Pectren.* Phany, Aldrov, &c.

Protren. Chem. 1784. Bolten, 1798.

Panpora. Megerle, 1811.

JantRA. Schum. 1817.

NeitHEa. Drouet. 1824.

JANERA. G. B. Sow. Jr. 1842.—P. maximus.

Pecten. Rumphius, 1705. Browne, 1756. Chem. 1784.
OstREA (sp.). Linn.

Araqus (sp.). Poli. 1795.

Cuuamys (sp.). Bolten, 1798.

* Etym. :—- Pecten, a comb.

BIVALVIA. 21

Amusivum (sp.). Chem. 1784.

PALLIOLUM. Td. =
Pyxis. Id. -
PERa. Id. - —P. opercularis.

Patitium. Martini, 1773. Schum. 1817.
DENTIPECTEN. Riéippell, sec. Gray.

DeEcaDoPEctEN. Riippell, sec. Swains.
Psgeup-AmusiuM. Chem. 1784.—P. tigerinus.
Amusium. Rumph. 1705. Chem. 1784. Schum. 1817.
PLEURONECTES. Schlotth. 1820.

PLEURONECTIA. Swains. 1840.—P. Gerardit.

Generic Character. Shell ovate, or suborbicular, subequilateral, inequivalve, with
a projecting, generally unequal auricle, on each side of the umbo, surface rayed with
striz, or more or less elevated costz; beaks approximate and acute. Hinge with a
linear groove across the dorsal part of the auricles for the ligament, and a triangular
pit or fossette beneath the umbo for the cartilage. Muscular impression of the mantle
entire but ill defined ; adductor large, excentric.

Animal resembling the shell without the auricular appendages, its mantle dis-
connected on all sides ; the margins bearing generally two rows of tentacular filaments,
at the base of which are arranged a series of ocelli or rudimentary eyes ; foot small,
subcylindrical, containing a groove from which is spun a byssus for its attachment ;
one large and powerful adductor muscle: no siphonal tubes. Sexes united.

This is a well and strongly-marked genus, generally ornamented with rays, like the
expanded sticks of a lady’s fan: these in some species are large and highly elevated,
while in the more aberrant forms they are nearly obliterated, merging into some which
are perfectly smooth, the gradations from the one to the other are so imperceptible as
to be without any definable line of demarcation, and although this group has been
separated into several Genera, there is no good or permanent character by which they
can be distinguished.

In some, the valves are very unequal in size, while in others there is scarcely a
perceptible difference, though in most species, by close observation, a trifling
inequality may he detected. ‘Those, in which one valve is very convex, while the
other is flat, or even concave in its young state, have mostly the larger one buried in
the sand, resting in a horizontal position, so that the flat one opens upwards, like the
lid of a box, these, when young, are furnished with a byssus, the opening for which
is visible in the smaller shell, but becomes obliterated in the adult. The animal
probably, in all the species, is capable of producing a byssus for attachment, this,
however, is mostly made use of by the young, as when more advanced in growth it
appears to be possessed of a considerable degree of locomotive power, which is often
employed so as to make considerable progress through the water by means of its large
and powerful adductor after opening the valves, and flapping them suddenly together
with great rapidity; some species are probably always stationary, as we find at all

22 MOLLUSCA FROM THE CRAG.

ages an opening in one valve through which a byssus of considerable magnitude
might have passed ; others fix themselves to rocks or foreign bodies by the spinous or
imbricated processes of their valves; when fixed like P. pusio, it is by the right valve,
which is also the one wherein is left an opening for the byssus, and the one also like
P. maxima, which the animal buries in the sand, it may, therefore, always be considered
the lower valve : this is sometimes the most convex, while in those that are free, the
greater convexity is generally in the left or upper valve, which, in the living shell, is
the more highly coloured.

This is purely a marine genus, and in the recent state has a very extended
geographical distribution, being found in almost all parts of the world, while its
vertical range is also considerable, inhabiting the seas at various depths ; it is also of
great antiquity, species having been found as low in the Secondary Series as the Lias,
and are continued upwards through nearly every period to the present time; it is
largely developed in the newer Tertiaries, and is exceedingly abundant as an existing
genus, upwards of a hundred species being already known. It has been quoted as an
inhabitant of the Palzeozoic Period, but the specimens found in the Coal Measures and
Mountain Limestone Rocks, present differences that are considered as generically
distinct, and they have been separated by Prof. M‘Coy under the name of Aviculopecten
differmg from the true Pectens in the absence of a cartilage-pit, and in the inequalities
of the auricles being reversed, thereby connecting it with Avicula.

It is to be feared, that many of our Tertiary specimens have been erected into
species without sufficient claim to such distinction, and that several will be found upon
further examination to be merely variations of form and sculpture of those which are
perhaps more than commonly disposed to deviate from what may be considered as the
typical form of long and well-known recent species.

This genus flourished most abundantly im the Crag Seas, and the modifications in
the ornamental portions of most of the species render their correct appropriation a
task of no ordinary difficulty.

1. PEcTEN MAxiIMus, Linneus. Tab. IV, fig. 1, a—4, and Tab. VI, fig. 7, a—é.
Lister. Hist. Conch., lib. iii, par. 1, fig. 1 A, 1687.
Ostrra Maxima. Linn. Syst. Nat., p. 1144, No. 185, 1767.
— os Knorr. Delices des Yeux, xiv*, fig. 1, 1766.
— — Donov. Brit. Shells, pl. 49, 1800.
— W. Wood. Ind. Test., p. 47, pl. 10, fig. 1, 1825.
_ — Broce. Conch. Foss. Subap., p. 572, No. 16, 1814.
PECTEN Maximus. Mont. Test. Brit., p. 143, 1803.
— — Chem. Conch. Cab., vii., p. 268, pl. 60, fig. 585, 1782.
_ — Crouch. Int. Lam. Conch., p. 20, pl. 12, fig. 13, 1827.
— —_ Brown. Mlust. Conch. Gr. Brit., pl. 32, fig. 1, 1827.
— — Desh. 2d ed. Lam., t. vii, p. 129, 1836.
— — Payr. Cat. Moll. Cors., p. 71, No. 132, 1826.
— — S. Wood. Catalogue, 1840.

BIVALVIA. 23

PucTEN maximus. Chenu. Ilust. Conch. Peeten, pl. 2, figs. 1—3, and pl. 29, figs. 1—18.
— a Loven. Ind. Moll. Scand., p. 30, 1846.
— _ Alder. Cat. Moll. North., p. 76, 1848.
— _ Ford. and Hanl. Uist. of Brit. Moll., vol. ii, p. 296, pl. 49, 1849.
— — Sismond. Syn. Meth. An. Invert. Pedem. Foss., p. 13, 1847.
— — G. B. Sow. Jr. Thesaur. Conch., vol. i, p. 45, pl. xv, figs. 98-100, 1847.
— vuLearis. Da Costa. Brit. Conch., p. 140, pl. 9, fig. 3.
— compLanatus. J. Sow. Min. Conch., t. 586, 1828.
_ — S. Wood. Catalogue, 1840.
— — J. Morris. Cat. Brit. Foss., p. 114, 1843.
— — Nyst. Coq. Foss. de Belg., p. 285, pl. 22 bis, fig. 1, 0, b!, 1843.
— sImitis. G. B. Sow. Jr. Thes. Conch., p. 46, pl. 16, figs. 116, 117, 1847.
— mMeEDIus. Chem. Conch. Cab., t. vii, p. 272, t. 60, figs. 586, 587, 589.
— — Desh. 2d ed. Lam., t. vii, p. 130, 1835.
— — Phil. En. Moll. Sic., vol. ii, p. 59, 1844.
— — Chenu. Mlust. Conch., pl. 4, figs. 2—6.
~- _ Sismonda. Syn. Meth. Ped. Foss., p. 13, 1847.
— GRanDIs. J. Sowerby. Min. Conch., t. 585, 1828.
— _— S. Woodward. Syn. Tab. Brit. Org. Rem., p. 19, 1830.
a —_ S. Wood. Catalogue, 1840.
— — J. Morris. Catal. Brit. Foss., p. 114, 1843.
= — Nyst. Coq. Foss. de Belg., p. 284, pl. 21, fig. 6, 6, 6, and pl. 22,
fig. 1, a, 6, 1844.
Ency. Meth., pl. 209, fig. 1, a, 0.

Spec. Char. Testaé inequivalvi, suborbiculari; valvé dextré vel inferiori convexd,
superior planulatd ; radius magnis, 13—14 rotundatis, longitudinahter striaté ; marginibus
lati-crenulatis ; auriculis equalibus.

Shell inequivalved, suborbicular; right or inferior valve convex ; left or upper
valve flat, or very slightly inflated; ornamented with 13 or 14 large, rounded, and
striated ribs or rays; margin broadly indented; ears equal.

Length, 543 height, 42 inches.

Locality, Cor. Crag, Sutton, Aldbro’, Ramsholt, Gedgrave.

Red Crag, Sutton, Bawdsey.
Northern Drift, Ireland (Forbes).
Recent, Britain and Northern Seas, Mediterranean ¢ Red Sea?

This is very abundant in some localities of the Coralline Crag, and particularly
variable in its exterior ornament. The peculiar arrangement of the striated portion of
the rays, which some of the specimens have assumed, induced authors who have
described the Crag shell, to consider it as wholly distinct from the recent British
species, and I was long of the same opinion; but the examination of numerous speci-

mens in the cabinets of my Crag collecting friends, has shown a union between the
" extremes of sculpture, as represented in the variety grandis, and that which is commonly
exhibited in the generality of recent specimens, by small and almost imperceptible
variations, so as to prevent a distinct line of demarcation to be drawn between

24 MOLLUSCA FROM THE CRAG.

them, and as such, they are here considered only in the light of varieties of the living
British shell.

M. Nyst, seems to consider the variety grandis as a modified form of P. Jacobeus,
from which opinion I must dissent, believing it to be, as above stated, specifically
united with our own species P. maximus. In P. Jacobeus, the coste or rays are
broader in proportion to the intermediate depression, and are more quadrate: those
upon the Crag shell are often as much elevated, but always more or less rounded,
without the abrupt or sharp edges, which distinguish the Mediterranean shell. The
most prominent character in the var. grandvs, is the distinct ray in the centre of the
depression, while a corresponding kind of sulcus or furrow runs down the centre of the
large ray, dividing it into two parts ; this character, which in some specimens appears
so strongly marked, that it alone would be quite sufficient for specific distinction, be-
comes in var. complanatus scarcely discernible with the rays very much depressed, and in
those specimens with this division in the rays, each side appears to be again divided
by a less distinct line, or arranged in pairs. P. medius. Chemn. is said, by its author, to
be intermediate between Jacobeus and Maaimus, partaking, in some degree, the.characters
of both, but from the figure and description appears to be only a variety of the latter.

A species from Australia, somewhat resembles our Crag fossil, in having the inter-
mediate small ray, but it has no bipartite division of the large rays, while they are
rounded and simple on the flatter or upper valve, and may, therefore, only be looked
upon as the representative of our species. In the young state, our shell is nearly
smooth, while the upper or left valve is concave on the upper surface, in which stage of
its existence it was probably furnished with a byssus, as an opening is then visible beneath
the auricle of the convex or right valve, but entirely obliterated in the adult shell.

In the Coralline Crag at Ramsholt, many beautiful specimens have been found with
the valves united, in what was, probably, a deeper portion of the sea at that period,
in association with Pyrula, Pholadomya, Lingula ; forms, now found only in Tropical
or Sub-Tropical Seas, while at the same locality are numerous individuals of species,
whose homologues are living at the present day upon the Scandinavian Coast.

The range of this species (mawimus), in the living state, is given by the authors of
the ‘ Hist of Brit. Moll.,’ from the Coast of Norway to Gibraltar. Payraudeau quotes
it as found, though rarely, on the West Coast of Corsica; and Born speaks of it also
as from the Mediterranean.

2. PEcTEN GeRaARDII, WVyst. Tab. V, fig. 5, a—é.
Pecten Gerarpit. Myst. Rech. Coq. Foss. Prov. d’Anv., p. 19, No. 75, pl. 3, fig. 75,
1835.
— — Potiez. et Mich. Cat. des Moll. de Douai, t. 11, p. 78, No. 32, 1844.
— — Nyst. Coq. Foss. de Belg., p. 300, pl. 18, fig. 11, 1844.
— suBD1APHANUS. S. Wood. Catalogue, 1840.

Spec. Char. Testé orhiculari, subhyalind, inequvalvi, equilateral, radiatim striata,
et divaricatim insculpté ; auriculis inequalibus; margine tenuissimé crenulatd.

BIVALVIA. » 25

Shell orbicular, subpellucid, inequivalved or somewhat plano-convex, equilateral,
externally covered with fine longitudinal rays, visible only near the margin, and beau-
tifully sculptured with diverging or divaricating striz, auricles unequal.

Diameter, 2 inches.

Locality. Cor. Crag, Ramsholt, Sudbourn, and Gedgrave.

This beautiful species is exceedingly abundant at the latter locality, where, how-
ever, the valves are always separated. At Ramsholt, they are somewhat less abun-
dant, and the valves are there found in their natural position.

From the figure and description given by M. Nyst, above referred to, there is little
doubt, that the English Crag shell is the same as the one found in the Campinian
beds of Belgium. Our shell is very thin, but strong, with irregularly-marked lines of
increase ; the right valve always more or less flattened, while the opposite one is
tumid or convex. Auricles very unequal and rayed, or costated, with a moderate
sized opening beneath the anterior one of the right valve, this is almost obliterated in
the adult shell, a rather large triangular cartilaginous area overhanging or projecting
into the interior. The impression formed by the edge of the mantle parallel with the
margin, and extending to about two thirds the length of the shell, that by the
adductor, less distinctly defined. The contour of the shell is nearly circular, a little
interrupted with a pair of rather high shoulders. A dark line diverges from the umbo,
within which the shell is of a lighter colour, like that in P. corneus, being, however,
perfectly distinct from that species. The beautifully curved or divaricating strize
(from the absence of longitudinal or radiating ribs), are visible upon the smooth sur-
face of the shell with the naked eye. An American fossil, Pecten Virginianus,
Conrad. ‘Foss. of the Med. Tert. of the United States, p. 46, pl. 21, fig. 10, 1838,
appears to resemble our shell in many characters, but from the representation it differs
in being longer than high, and has the ears more equal and larger.

3. PECTEN simMILis, Laskey. Tab. V, fig. 4, a—e.

PrcreN sIMitis. Laskey. Mem. Wern. Soc., vol. i, p. 387, pl. 8, fig. 8, 1811.
— — Brown. Mlust. Conch. Gr. Brit., pl. 32, figs. 5, 6, 1827.
— — Flem. Brit. An., p. 384, 1828.
— — Forb. Rep. on Egean Invert., p. 183, 1848.
a — Alder, Cat. Moll. North. and Durh., p. 77, 1848.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 293, pl. 52, fig. 6, and
‘ pl. 8, fig. 1, 1849.
OstrREA TUMIDA. Turt. Conch. Dict., p. 132, 1816.
PEcTEN TuMIDUs. Turt. Brit. Biv., p. 212, pl. 17, fig. 3, 1822.
= _ Flem. Brit. Anim., p. 384, 1828.
— — Thorpe. Brit. Mar. Conch., p. 117, 1844.
— —_ S. Wood. Catalogue, 1840.
— — Lovén. Ind. Moll. Scand., p. 36, 1846.
— — G. B. Sow., Jr. Thes. Conch., vol. i, p. 57, pl. 13, figs. 27—29, 1847.
— pyemamus? Phil. En. Moll; Sic., vol. ii, p. 61, 1844, (not Gold/.)
+

26 MOLLUSCA FROM THE CRAG.

Spec. Char. Testd minutd, suborbiculatd, equvalvi, subequilaterah, tenui, subhyalind,
planulatd, glabra ; auriculis subequalibus, in valud dextra anticé longiori, rotundatd, posticé
rectangulaté ; sinu brevi, acuto.

Shell small, suborbicular, equivalved, subequilateral, thin, subpellucid, flattened,
smooth ; auricles nearly equal; the anterior one of the right valve rather the longer
and rounded, on the posterior side it forms a right-angled triangle, with a short and
acute sinus.

Diameter, ¢ inch.

Locality. Cor. Crag, Sutton. Recent Britain, Finmark, Aigean Sea.

This pretty little shell is particularly abundant at Sutton, in the Coralline Crag, to
which formation, as far as is at present known, it is restricted: its minuteness and
fragility may, however, be one cause why it has not yet been found in the Red Crag,
as it appears to be a species possessed of capabilities to endure a considerable range in
temperature, being quoted by Dr. Lovén as having been obtained on the coast of
Finmark, while Professor Forbes procured it in considerable numbers from a great depth
in the Aigean Sea, some specimens of which he has obligingly given me, for the pur-
pose of comparison with the British fossil.

There are some slight differences between the recent shell and the fossil, but
which can hardly be considered of sufficient importance to justify it.being ranked
as more than a variety; the living species in several characters is subject to
variation. The specimens from the Aigean, which were obtained at the depth of
100 fathoms, are rather larger than any I have from the Crag, measuring a little
more than a quarter of an inch in its longitudinal diameter, and a trifle less in .
the height, with the auricles unequal, the anterior one, more especially in the
right valve, less than the posterior, but this is not a permanent character, as in
some specimens they are equal in size. The Crag shell does not exceed in
diameter a quarter of an inch, very rarely attains this magnitude, and the dorsal
margin, or rather the ears of the shell, extend to 5-6ths of its entire length. In
the right valve the anterior auricle is as large as the posterior one, and completely
rounded with a small sharp sinus beneath it, as if the shell, in the living state, had been
supplied with a byssus. There is a slight peculiarity in this species in the right valve,
attributable probably to the presence and size of the byssus ; the diverging line from
the umbo is on the posterior side rather convex, while on the opposite, or beneath the
projecting ear, it is distinctly concave; in the left valve the auricles are equal in size,
and the divergence of the edge of the shell more regular, forming an angle of 90°;
this valve is, in the recent state, ornamented with coloured markings of a zigzag,
or what is called Vandyke shape, traces of these colours are still remaining in some of
the Crag specimens, one of which has only a single line of divergence from near the
centre, somewhat like the ornaments upon Lucina divuricata. There is also a slight
inequality in the depth or convexity of the valves, the right or lower one being a little
more tumid than the other.

BIVALVIA. 27

P. Groenlandicus, Lovén and G. B. Sow., Thes. Conch., p. 57, Pl. 13, fig. 40,
appears to differ from our shell only in being somewhat larger.

4. PECTEN TIeRINUS, Miller. Tab. V, fig. 2, a—y.
PEcTEN TIGRINUS. Miill. Zool. Dan., ii, p. 26, pl. 60, figs. 6—8, 1776.
— — Desh. 2d ed. Lam., t. viii. p. 155, 1835.
— — Nyst. Coq. Foss. de Belge, p. 303, pl. 23, figs. 4—10, 1844.
— — Lovén. Ind. Moll. Scand., p. 31, 1846.
— — Alder, Cat. of Moll. North. and Durh., p. 77, 1847.
—_ — Ford. and Hanl. Hist. of Brit. Moll., vol. ii, p. 285, pl. 50, figs. 8—11.
— oOBSOLETUS. Penn. Brit. Zool., vol. iv, p. 322, t. 64, fig. 3.
— —_— Don. Brit. Shells, vol. i, t. i, fig. 2, 1799.
=s _ Mont. Test. Brit., p. 149, and sup., p. 57, 1808.
— — Turt. Brit. Biv., p. 213, pl. 9, fig. 6, 1822.
— — Brown. Mlust. Conch. Gr. Brit., pl. 33, fig. 6, 1827.
— — J. Sowerby. Min. Conch. t. 541, figs. 1—8, 1828.
_ — Nyst. Rech. Coq. Foss. d’Anv., p. 19, No. 74, 1835.
— — S. Wood. Catalogue, 1840.
— — J. Morris. Cat. of Brit. Foss., p. 115, 1843.
_— — Thorpe. Brit. Mar. Conch., p. 118, 1844.
— paRvus. Da Costa. Brit. Conch., p. 155, 1778.
— .a&vis. Penn. Brit. Zool., vol. iv, p. 102.
_ _— Mont. Test. Brit., pp. 150, 579, pl. 4, fig. 1, 1803.
— — Turt. Brit. Biv., p. 212, 1822.
— — Brown. Illust. Conch. Gr. Brit., pl. 33, fig. 7, 1827.
— pomesricus. Chem. Conch. Cab., t. xi, p. 261, pl. 207, figs. 2030—2036, 1783.
OstREA OBSOLETA. Turt. edit. Linn., vol. iv, p. 266, 1806.
— — W. Wood. Ind. Test., p. 50, pl. 10, fig. 37.
_— — Mawe. Linn. Conch., pl. 14, fig. 6.
— TIGERINA. Tuwurt. edit. Linn., vol. iv, p. 268, 1806.
— avis. Mat. and Rack, Linn, Trans., vol. viii, p. 100, pl. 3, fig. 5, 1807.
— — W. Wood. Ind. Test., pl. 10, fig. 38.

Spec. Char. Testé equivalvi, equilaterah, suborbiculari ; radiaté, radiis varits,
interdum obsoletis, stris subtilissimis arcuatim divergentibus ornatd; auriculis valdé
inequalibus.

Shell equivalve, equilateral, suborbicular ; costated costz variable, sometimes
obsolete, or small and numerous, sometimes arranged in fives; ornamented with fine
curved and diverging striz, ears very unequal.

Diameter, | inch.

Locality. Cor. Crag, Sutton, Ramsholt, Gedgrave, Sudbourn.

Red Crag, Sutton, Bawdsey, and Walton Naze.
Recent, Britain and North Seas.

This is a very abundant species in the Coralline Crag, with as great a range in

28 MOLLUSCA FROM THE CRAG.

variation as is exhibited by those obtained in our own seas at the present day. In the
Red Crag, specimens are much more scarce, although var. 6 I have seen only from
this Formation.

From the great diversity of forms displayed by this animal, it is not to be
wondered at, that it should have been separated into several species: with variations
exceeding in appearance what are generally considered as sufficient for specific dis-
tinction, there is no permanent character that will justify their separation. In the
Crag as well as in the recent state, specimens may be obtained presenting every
minute gradation, and these apparently different forms are now justly included under ~
one name.

In var. a the shell is nearly smooth (/evis, Penn.), or at least without any distinct
longitudinal ribs or striz, or with the edges only presenting these radiations; this
may be considered as one extreme of the species, while the other variety exhibits five
large elevated ridges or ribs; these are generally separated, and in pairs, though they
are sometimes simple, the intermediate spaces are filled up with three or more rays.
Var. B may be called lenticular, with numerous fine rays covering the entire surface,
sometimes single, sometimes in pairs; var. y has four or five raised ribs, as before
described ; var. 6 has from seven to nine rays, which are themselves faintly striated,
while the intermediate spaces are also filled with radiating lines ; but these forms are
not permanent, and specimens uniting some of the characters of each may be commonly
obtained. Every specimen is strongly marked with fine divaricating striz, in a curving
direction from the umbo to the sides. In the young state the shell is often very scabrous,
the rays being covered with regularly raised imbrications. The general form may be
described as suborbicular, though the greater diameter is from the umbo to the ventral
margin. The auricles may be considered its most distinguishing character; these are
very unequal, the posterior one small, nearly obsolete, while that on the anterior side
is large, generally costated, or coarsely rayed. In the early stages of its growth, the
shell is always regularly convex or lenticular, but in some specimens, when at a certain
size, its form is altered by the enlargement of the shell on the inner edge of the margin
instead of outwardly, so as to give a greater space to the interior without much in-
creasing the diameter of the shell, and this character is exhibited in both valves.
Fig. 2, g,is what in my Catalogue was enumerated with doubt as a new species, under
the name ewoletus, but which probably is only a giant monstrosity of this species, as
the ordinary form is well displayed on the outside, beyond which, by apparently an
extra effort of growth, it has imduced a deposit of calcareous matter, till it has
reached a diameter of 1} inches, thus much exceeding the general size of this species,
which is rarely more than one inch. Fig. 2, a, is from a specimen belonging to Mr
Bridgman, obtained in the Mammaliferous Crag, near Norwich.

The animal in the recent state is said to range from 12 to 60 fathoms, while 18 or
20 is its most favorite depth.

BIVALVIA. 29

5. PecteENn Brust, Payraudeau. Tab. V, fig. 3, a—é.

Precten Brunt. Payr. Cat. Moll. de I’Ile de Corse, p. 78, pl. 2, figs. 10—14, 1826.
a Desh. Append. Lyell’s Princ., vol. iti, p. 14, 1833.
— — G. B. Sow., Jr. Thesaur. Conch., vol. i, p. 70, pl. 20, figs. 241-2, 1847.
— — Chenu. Illust. Conch. Pecten, pl. 39, fig. 6, a—e.
— Prcrus. Goldf. Pet. Germ., vol. ii, t. 97, fig. 4, a—c, 1830 (not Da Costa).
— striatus? Goldf. Pet. Germ., yol. ii, t. 96, fig. 3, a—d.
— Laman. WNyst. Coq. Foss. de Belg., p. 305, pl. 22, fig. 5, a—é, and pl. 24,

fig. 5, 1844.

— Panporx? Desh, Exped. Scient. de Morea, pl. 2, figs. 12—14, 1833.

Spec. Char. Testé suborbiculari, equivalvi? cequilaterali, convewiusculd ; radiatim
costatd, costis 18—20 convewis inequalibus, longitudinaliter tenuissimé lineatis, in juventd
nodosis vel subimbricatis ; auriculis alteris minimis, radiantibus.

Shell suborbicular, equivalve ? equilateral, slightly convex ; costated with 18 to 20
unequal rounded ribs, finely striated longitudinally ; and nodose or imbricated in the
young state; auricles unequal and rayed.

Diameter, $ an inch.

Locality, Coralline Crag, Sutton. Recent, Mediterranean.

Five or six separated valves are all that I have obtained, and these appear to cor-
respond with the recent species above referred to. Four localities are given by
Payraudeau, of recent habitats, who says it is “peu abondant.” The shell figured
by Nyst is presumed to be the same, from the disposition of the rays; but he speaks
of irregular and oblique strize upon the sides of the shell, like those upon “grinus;
these I have not been able to detect in my specimens, which, however, may but ill
display such sculpture, as they are, probably, only young individuals, not measuring
more than half the diameter of the Belgian fossil; but from the representation,
there is a slight difference, the auricles of his shell are rather more rounded, and
more unequal, and approach nearer in that character to one of the varieties of
tigrinus.

Our’ shell may be further described as having rounded rays generally single, some-
times arranged in pairs, but in no regularity in either the right or left valve, while the
whole surface, as well on the costae as between them, is covered with radiating
striz, these appear like linear markings in the shell, and not upon it, the line being
alternately of a light and dark colour, that upon the centre of each rib, larger or
broader than. the rest.

In the young shell, the rays are ornamented with nodose protuberances, and the
interstices have then also a raised portion of the shell, so that, in its young state, the
surface is prettily cancellated. The auricles are unequal, the anterior one being the
larger of the two, though not displaying so great a disparity as in figrinus ; they are
sharp and rectangular, and not the least rounded, covered with prominent rays, which
are strongly decussated by raised lines of growth: there is a small byssal smus under
the anterior auricle.

30 © MOLLUSCA FROM THE CRAG.

This is quite distinct from any of the varieties of P. tzgrinus, the larger or more
rounded form of the rays, as well as less inequality in the auricles, will distinguish
it; and in all the varieties of that species, strongly marked divaricating striz, or
curved lines radiating from the umbo, may easily be observed, but I have been unable
to detect such markings upon my specimens of this species, although individuals of
figrinus, much less in size, exhibit them distinctly ; and it seems also to be specifically
different from P. Dumasii, in which the rays are larger, fewer, and more prominent,
and the auricles of our shell are comparatively larger than those in that species. In
the recent state, this is, probably, a deep water species, as Payraudeau speaks of his
specimens having been obtained by means of the dredge.

6. PECTEN DANICUS, Chemnitz. Tab. IV, fig. 2.

Prcten Danicus. Chem. Conch. Cab., t. xi, p. 265, pl. 207, fig. 2043, 1795.
= — G. Sow. Thesaur. Conch., vol. i, p. 61, pl. 12, figs. 16 & 187.
- Forb. and Hani. Hist. Brit. Moll., vol. ii, p. 288, pl. 52, figs. 1,2, 7—10.
— GLaBRIs. Brown. Ill. Brit. Conch., pl. 32, figs. 3, 4, 1827.
— Dvmasrt. Payr. Cat. Moll. de I’Ile de Corsi., p. 75 pl. 2, figs. 6, 7, 1826.
— Desh. Append. Lyell’s Prine., vol. iii, p. 15, 1833.
— — Forbes. Rept. Hgean Invert., p. 183, 1843.
a as Jeffreys. Aun. Nat. Hist., vol. xix, p. 313.
— aspERsus. Desh. 2d ed. Lam., t. vii, p. 136, 1836.
— _ Phil. En. Moll. Sic. vol. i, p. 82. 1836; and vol. 1, p. 57, 1844.
— Jamusonr. Smith. Mem. Wern. Soc., vol. viii, p. 58, pl. 2, fig. 1, 1838.
— Brown. Ilust. Conch. Gr. Brit., 2d edit, p. 73, pl. 25, fig. 7.
— SEPTEMRADIATUS. Loven. Ind. Moll. Scand., p. 31, 1846.
— riraptatus. Mill. Zool. Dan., vol. ii, p. 25, pl. 60, figs. 1, 2, (fide Loven and Desh.)
OsTREA HYBRIDA. Gmel. Syst. Nat., p. 3318, 1788 (fide Loven).
— — W. Wood. Ind. Test., p. 48, pl. 10, fig. 10, 1825.
_ TRIRADIATA. Turt. ed. Linn., vol. iv, p. 268, 1806.
—_ — W. Wood, Ind. Test., p. 50, pl. 10, fig. 39, 1825.

— SEPTEMRADIATA. Id. - - p. 268, 1806.
— InFLexa. Poli. Test. Nicil., vol. i, p. 160, t. 28, figs. 4, 5.
==" OLAV A age aes, - - p. 161, t. 28, fig. 17.

Prcten Pseup-Amusioum. Desh. Exped. Scient. de Morea, p. 231, pl. 2, figs. 9—11, 1833.
Ency. Meth., pl. 212, fig. 6.

Spec. Char. Testd subrotundaté, equilaterali, radiis 5—6 rotundatis inequalibus,
striatis ; auriculis inequalibus.

Shell subcircular, equilateral, thin, with rounded or convex rays varying in number
from 5 to 6 striated; auricles unequal.
Diameter, 1 inch.

Locality. Clyde Beds. Recent, Aigean, and Scandinavia.

Although this species, in the recent state, has been obtained in the Atgean, as
well as in the Mediterranean Sea, and is quoted also by Philippi as an abundant fossil

BIVALVIA. 31

in the Sicilian Beds, I have not yet seen it from any of the three Crag Formations of
Essex, Suffolk or Norfolk. As it is a fossil in the Clyde Beds, and may, probably, be
hereafter found in the Crag, it ought not to be here passed over in silence. The
specimen figured (which is the right valve) was given to me by James Smith, Esq.,
of Jordan Hill, and is undoubtedly identical with the British shell recently obtained in
considerable plenty by Mr. George Barlee.

Our specimen contains a good deal of animal matter, with some slight remains of
colour, as indicative of its comparatively modern origin. The shell like that of
P. tigerinus, is ornamented with curved radiating or diverging striz, but less promi-
nent and distinct, and most visible at the lateral edges. A specimen of P. Dumasiz,
given to me by Professor Edward Forbes, which he obtained from a great depth in the
Aigean Sea, does not appear to differ specifically from the British shell, and I have
followed his example in uniting the two. Our fossil, however, appears to agree with
the recent British specimens better than with the Dumasii from the Mediterranean, in
having a rather larger posterior auricle; but my specimen from the Aigean differs also.
in that character from the Mediterranean shells, in having as large an auricle com-
paratively as the British specimens. The number of ribs is a variable character ;
sometimes the right valve has six, when the left one has only five, the depressions of the
one valve corresponding to the elevations of the other, and vice versa.

In this, as in most of the species of this genus, the auricles are comparatively
larger in the younger shell than in the adult; my specimen, is a full grown shell, with
six ribs or elevations, and the whole surface rayed or striated longitudinally, made
rough or scabrous by elevated lines of growth, and the diverging or curved strie
visible only at the sides.*

7. PecrEN Princeps, J. Sowerby, Tab. VI, fig. 1.

Pecten Princers. J. Sow. Min. Conch., t. 542, fig. 2, 1826.
— — Woodward. Geol. of Norf., p. 44, 1833.
— — S. Wood, Catalogue, 1840.
— — Morris. Cat. of Brit. Foss., p. 115, 1843.
— Cutwrontus? Say. Journ. Acad. Nat. Sci., vol. iv, p. 135, pl. ix, fig. 2, 1824.
— aD, 2 Conrad. Foss. of the Med. Tert. of the United States, p. 47, pl. 23,

, fig. 1, 1838.

— sUBLEVIGATUS? Juv. Nyst. Coq. Foss. de Belge, p. 298, pl. 24, fig. 4, 1844.

Spec. Char. Testa, orbiculari, subinequivalvi, convexd, longitudinaliter costatd, costis
numerosis confertis, subsquamosis, interstitiis divaricatim striatis; auriculis magnis sub-
aequalibus ; valvd deatrd minori.

Shell orbicular, slightly inequivalve, convex, externally ornamented with numerous
close set, rounded and slightly squamose or imbricated strize, with a small inter-

* A specimen much worn, and without its auricles, very recently found in the Red Crag, is in my
Cabinet, and may possibly be of this species, but it is too much mutilated for fair examination.

32 MOLLUSCA FROM THE CRAG.

mediate ray in the aged shell, and fine diverging striz visible between the rays; ears
large, nearly equal, and rayed ; right valve the smaller of the two.

Length, 5%. Height, 5z inches. ,

Locality. Cor. Crag, Ramsholt.

This noble shell appears not to have lived beyond the Period of the Coralline Crag,
at least, I have not seen it from any more recent deposit, although Woodward, in his
‘Geol. of Norf.’ has included it in his List of Fossils from the Mammaliferous Crag at
Thorpe, with the letter a at the end of the locality, denoting its abundance, but
I have not been able to see a specimen, or ascertain that it was even found in that
formation, perhaps, fragments or imperfect specimens of P. [slandicus may have been
mistaken for it.

This is the largest species of the genus belonging to the nearly equivalved section,
equalling in magnitude the common Scallop. Pecten Magellanicus somewhat re-
sembles this shell, and may be considered its representative on the other side of the
Atlantic; but it has not the rays so distinctly marked or elevated as those upon
the Crag shell, and is a flatter or more compressed species, with a few other minor
distinctions sufficient to separate the two.

An American fossil above referred to, as far as can be determined by the figure and
description, appears so closely to resemble our shell, that they are here considered as
probably the same species; some slight differences may, however, be pointed out, as
our reliance is entirely upon the representation, without the opportunity of comparison.
Our shell has the auricles large and unequal, those on the posterior side being much
the smaller, while in the American fossil they appear more equal, and somewhat less,
and the rays are represented as bifurcating, or double in number, on the outer part of
the shell, or its latter growth; the Crag shell has from 70 to 80 small and convex
rays, rounded and slightly imbricated, but never angulated, the distance between them
about equal to the rays; at the outer part of my largest specimen is an intermediate
ray, thereby resembling the figure of the American fossil; between the rays may be
seen fine diverging or divaricating striz, crossing the lines of growth in an oblique
direction. Under the anterior auricle of the right valve is a large opening. The
valves are closed nearly all round, slightly gaping at the shoulders. The same sized
rays ornament the auricles, which are also scabrous. Oysters and Barnacles are
attached to the roughened surface of the shell, and may be seen, sometimes upon the
right, in others on the left valve.

This was found, iz stu, in the tranquil deposit at Ramsholt. Pecten sublevigatus
Nyst, so much resembles a small specimen in my possession, that it is probably only
the young state of this species.

Say’s name appears to have priority of date, but from the uncertainty of identifi-
cation, the much more appropriate one given by Mr. Sowerby has, for the present.
been retained.

BIVALVIA. 33

8. PEcTEN pusio, Pennant. Tab. VI, fig. 4, a—e.

Lister. Hist. Conch., lib. iii, par. 1, figs. 9, 18? and 23? 1789.

Patiiotum? Chem. Conch. Cab., vii, p. 333, t. 67, figs. 635-6, 1784.

OstREA MINIATA. Born. Mus. Cees. Vind., p. 104, t. vii, fig. 1, 1780.
— mouLtisTriaTa. Poli. Test. Sicil., vol. u, p. 164, t. 28, fig. 14, 1795.
— pvusio. Don. Brit. Shells, vol. i, pl. 34, 1700.
— sinvosa. W. Wood. Ind. Test., p. 50, pl. 10, fig. 34, 1825.

Prcten pusio. Penn. Brit. Zool., vol. iv, pl. 61, fig. 65.
— — Turt. Brit. Biv., p. 215, pl. 17, fig. 2, 1822.
— — Payr. Cat. Moll. de I’Ile de Cors., p. 74, 1826.
— —_ G. B. Sowerby. Genera, No. 31, fig. 6.
= — Phil. En. Moll. Sic., vol. i, p. 84, and vol. ii, p. 58, 1844.
a: = Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 278, pl. 50, figs. 4, 5;

pl..51, fig.:7.

— opistortus. Da Costa. Brit. Conch., p. 148, pl. 10, figs. 3, 6.
— a Mont. Test. Brit., p. 148, and Sup., p. 61, 1808.
— — Lovén. Ind. Moll. Scand., p. 30, 1846.
— sinuosus. Turt. Brit. Biv., p. 210, pl. 9, fig. 5, 1822.
— — Brown. Illust. Conch. Gr. Brit., pl. 32, fig. 2, 1827.
as —_ Forbes. Geol. Surv. of Gr. Brit., vol. i, p. 86, 1846.
— spinosus. Brown. Illust. Conch. Gr. Brit., pl. 33., fig. 8, 1827.
— striatus. J. Sowerby. Min. Conch., t. 394, figs. 2—4, 1823.
— — Duyjard. Mem. Soc. Geol. de France, t. ii, pl. 2, p. 270, No. 3, 1837.
== — Nyst. Coq. Foss. de Belg., p. 301, pl. 15, fig. 1, b, 6, d, 1843.
— sERRATUS. Dubois. Conch. Foss. de Wolhyn. Podol., p. 73, pl. 8, fig. 5, 1831.
— qtLorta MARIS? Id. . - - p. 72, pl. 8, figs. 6 & 19, 183}.
— squamuLosus. Desh. Exped. Sci. de Morea, pl. 5, fig. 7—11, 1833.
— urmatus. Goldf. Pet. Germ., vol. ii, p. 59, pl. 94, fig. 6, a—d.
= = Chenu. Conch. Illust. Pecten, pl. 49, fig. 5.
— xLoneatus? Goldf. Loc. cit., pl. 94, fig. 7, a—c.

Hinnites pusio. G. B. Sow., Jr. Conch. Man., fig. 173.
os stnvosus. Desh. 2d ed. Lam., t. vii, p. 149, 1836.
= — G. B. Sow., Jr. Thesaur. Conch., vol.i, p. 79, pl. 20, figs. 1—3, 1847.
— IRREGULARIS. Desh. Ency. Meth. Vers., t. ii, p. 273, No. 1. ~

Spec. Char. Testé orbiculato-ovatd, subequvalvi, equilaterali, radiata, radiis confertis,
numerosis, 2—3 partitis, irregularibus, levibus aut scabris ; auriculis inequalibus.

Shell orbiculato-ovate, subequivalve, equilateral with numerous close-set rays, in
sets of two or three, irregularly scabrous, with very unequal auricles.

Longitudinal diameter, 2 inches; height, 23ths of an inch.

Locality. Cor. Crag, Sutton, Ramsholt, and Sudbourn.

Red Crag, Sutton, Bawdsey, Walton Naze.
Recent, Britain, Mediterranean, Bergen.

This shell is abundant im both formations, and in the Coralline Crag at Ramsholt
the two valves are often united. In the young state, the Crag shell so much resembles
the recent specimens of the same size, that it cannot be considered otherwise than

5

34 MOLLUSCA FROM THE CRAG.

identical, as suggested by Philippi, ‘En Moll. Sic., vol. i, p. 84, notwithstanding a
material change in its habits appears to have taken place in the modern shell, where,
after it has attained a certain age or magnitude, it attaches itself to some stone or
rock, by the entire surface of the right valve adhering by the scabrous or imbricated
portions of the rays, in consequence of which it is often distorted, moulding itself to the
inequalities of the body to which it is fixed, producing great variation in form, from
which circumstance the recent shell has been separated into two or more species.
This does not appear to have been the habit of the Crag shell, as amongst the
numerous specimens I have seen, there is no indication of its having been attached by
the exterior surface, but may have been a fixed species by means of a byssus, as in
all the right valves a large opening exists beneath the anterior auricle, so far
resembling the habits of the recent species in being fixed though by a different process.*
Some of my specimens have attained a diameter of rather more than 2} inches
from the umbo to the ventral margin, but, unlike the full-grown recent shell,
have retained their regularity of form throughout their whole existence. There is
often a slight obliquity in the shell, produced probably from its attached habits, the
large byssus causing the auricle on that side to be more elevated than on the
posterior, which is not only much smaller, but more depressed. The valves are nearly
equal in convexity, though the right one is a little the flatter of the two, and in general
the rays are arranged in pairs, unequal in size, the larger one being scabrous, sometimes
less regular with three of different sizes, and all imbricated, the exterior is, however,
very deceptive in this character, as in one variety which from the entire absence of
these imbrications as well as from a greater regularity in the rays, it was assumed to
be a distinct species, and passed in my catalogue under the name of sé¢rzaturus, which
there is reason now to believe is not entitled to that distinction. At the anterior
opening beneath the auricles, are five or six elevated ridges for the purpose, probably,
of keeping the byssus more spread, or in its place, and the shell appears to have
had a somewhat large cartilaginous area, as well as a broad surface for the attach-
ment of the ligament, the valves opening about five and twenty degrees. In the
young as well as in the adult shell, there is a great equality in the size of the
auricles.

In this, as in many species of this genus, the exterior is ornamented with fine
divaricating strize, crossing the lines of growth at nearly right angles, visible also in
the recent shell, and between the rays the surface is often subcancellated by the
reflexed or thickened margin of the shell at the varied periods of increase.

The recent shell is stated, by the authors of British Mollusca, to range from near
low water mark to 90 fathoms: most plentiful between 15 and 28. Its lateral range
extends from the Mediterranean to the Norwegian shores.

* Although never being itself fixed by the shell, its roughened exterior is well adapted for parasitical
animals and we, consequently, find Oysters or Barnacles adhering to the valves.

BIVALVIA. 35

9. PECTEN OPERCULARIS, Linnaeus. Tab. VI, fig. 2, a—d.
List. Hist. Conch., lib. iu, fig. 27.
OsTREA OPERCULARIS. Linn. Syst. Nat., p. 1147, No. 202, 1767.
— _ Born. Mus. Cees. Vindobon, p. 106, 1780.
— — Schrot. Hinleit in die Conchyl., iii, p. 317, t. ix, fig. 3, 1784.
— — W. Wood. Ind. Test., pl. 10, fig. 43.
— susrura. Don. Brit. Shells, vol. i, pl. 12, 1799.
— urmneaTa. Don. Brit. Shells, vol. iv, pl. 116, 1803.
— SANGUINEA. Poli. Test. Sicil., vol. ii, pl. 28, figs. 7-8.
— — ? Knorr. Delices des Yeux., t. iv, fig. 1, 1766.
— pLEBEJA. Broc. Conch. Foss. Subap., p. 577, t. 14, fig. 10, 1814.
Precten pictus. Da Costa. Brit. Conth., p. 144, pl. 9, figs. 1, 2, 4, 5, 1778.
— urmeatus. Id, - - pp. 147, pl. 10, fig. 8.
— — Mont. Test. Brit., pp. 147, 579, 1803.
— _ Chenu. Conch. Illust. Pecten., pl. 30, figs. 1, 2.
— opERcULARIS. Chem. Conch. Cab., vii, p. 341, pl. 67, fig. 646, 1782.
— — Mont. Test. Brit., p. 145, 1803.
— — Lam. Hist. des An. Sans. Vert., vi, p. 172, 1822.
— — Brown. IMllust. Conch. Gr. Brit., pl. 33, fig. 1, 1827.
— ae Payr. Cat. des Moll. de la Corse., p. 77, 1826.
— — Chenu. Conch. Illust. Pecten., pl. 48, fig. 3.
— —_ Goldf. Pet. Germ., t. ii, p. 62, tav. 95, fig. 6, 1833.
— — Phil. En. Moll. Sic., p. 82, t. 6, fig. 2, 1836.
-— — G. B. Sow., Jr. Thes. Conch., p. 53, pl. 17, figs. 141—146, 1847.
— — Lovén. En. Moll. Scand., p. 30, 1846.
— — Forb. and Hanl. Hist. Brit. Moll., vol. u. p. 299, pl. L, fig. 3%
L i, figs. 5, 6; Liii, fig. 7, 1849.
— svuLcatus. J. Sowerby. Min. Conch., t. 393, fig. 1, 1823.
— — Woodward. Geol. of Norf., p. 44, 1833.
= — Nyst. Rech. Coq. Foss. Prov. d’Anv., p. 19, 1839.
— ReEconpitus. J. Sowerby, Min. Conch., t. 575, figs. 5, 6, 1827.
= — Nyst. Rech. Coq. Foss. Proy. d’Any., p. 19, No. 73, 1835.
— os Potiez et Mich. Cat. Moll. de Douai, p. 77, pl. 49, figs. 1, 2.
— suBrurus. Turt. Brit. Biv., p. 210, t. 17, fig. 1, 1822.
— Avpovurni1. Payr. Cat. Moll. de Cors., p. 77, pl. 2, figs. 8, 9, 1826.
— pLEeBEtus. J. Sowerby. Syst. Ind., p. 244, 1835.
— — Bronn. Leth. Geog., ii, p. 916, t. 39, fig. 16, 1838.

— Sowersyr. Myst. Conch. Foss. de Belg., p. 293, pl. 22, fig. 3, 4’, and pl. 22 bis.
— Matvinz. Dubois de Montp. Conch. Foss. Wolhyn. Podol., p. 71, pl. 8, figs. 2, 3.

— FLavus? Id. - . - - ~~ | p-./2pk 85 fie, 7.
— RECTANGUIUS? Id. . - - - - p.72, pl. 8, figs.10,11.
— PULCHELLINUS? Id. - - - - - p70; pls; fic. 8:

— raprans? Nyst. Coq. Foss. de Belg., p. 294, pl. 24, fig. 3, 1844.

— 20-suntcatus. Miill. (fide Lovén.)
Description de Egypt Hist. Nat., pl. 13, figs. 5, 1—4, and pl. 14, fig. 8, 1826.
Ency. Meth., pl. 212, fig. 2.
Dale. Hist. and Antiq. of Harwich, p. 291, t. xi, fig. 1, 1730.

Spec. Char. Testd suborbiculari, subequvalvi, longitudinaliter radiata radiis 18 —26,

36 MOLLUSCA FROM THE CRAG.

squamosis, squamis crebris, transversis, interradios divercatim striate ; auriculis sub-
aqualibus ; valvd sinistra convextort.

Shell suborbicular, slightly mequivalved, covered with 18—26 imbricated or
squamose rays, squamz numerous and close set, between the rays are visible fine
divaricating striz ; auricles nearly equal; the left valve, the more convex one.

Diameter, 24 inches.

Locality. Cor. Crag, Passim.

Red Crag, Id.
Mam. Crag, Bramerton and Thorpe.
Recent, Britain, Finmark, and Mediterranean.

This is one of the most abundant shells, in the Coralline, as well as
in the Red Crag Formations, and is exceedingly variable as regards the ornament
and arrangement of its exterior, which has caused it to be separated into
many different species, so greatly, indeed, does it vary in this character, that
scarcely any description can be given of its sculpture, but what some deviation
may be observed, so as almost to induce an opinion, that such difference might
be considered as a specific distinction. The most abundant variety is that which
corresponds with the rough and imbricated shell, now found living in the
Mediterranean, figured and described as a new species by Payraudeau, under the
name P. Audouwint. This shell may be found in almost every locality, in the
Coralline as well as in the Red Crag.

Both valves may be described as somewhat convex, though the upper or left valve
is decidedly the more tumid of the two. Our shell is ornamented with more or less
rounded rays, divided into threes, varying in number from 18 to 26, these
are rather wider than the intermediate spaces, and are covered with rough imbricated
squamze, and the spaces between the ribs are generally imbricated in the same way.
In the young shell the tripartite form of arrangement is seldom to be seen, the rays
then being single, and this continues sometimes till the shell has increased to more
than an inch in diameter; and the division of the intermediate space into three rays,
does not, in some specimens, show itself until even a greater magnitude, by which the
young shell differs so materially in its ornament, as to have been made into new
species. In one variety of my Crag specimens, the rays are so strongly imbricated
with reflexed squame, that in my Catalogue, it was considered a distinct species,
and intended to have been described under the name scadrotus (fig. 2, c) ; but the pos-
session of more specimens and further examination, give reason to believe it to be only
a modification of the above species: in this, which, is somewhat of a young shell, the
ribs are single, but the imbrications are continuous undulating over and between the
ribs. The var. /ineolata, 1 have seen only from the Red Crag, and that but rarely.
P. reconditus, Min. Conch., is I conceive, to be only that form sometimes met with in
which the rays have preserved their unity until the specimen has attained a magnitude
of an inch anda half in diameter, although in some specimens, they separate into threes

BIVALVIA. 37

long before they attain that size, the separation of the rays generally producing a
corresponding ornament upon the intermediate spaces, although that often depends
upon the width of those spaces. This appears to differ from the London Clay shell
and I doubt its being Ost. recondita, Brander.

In my specimens from Barton, are two varieties, one not having more than 18 or 20
rays, while the other has 30—32, these are more rounded than in the Crag shell ; when
perfect, in general they are more or less eroded, they are striated both upon and between
the rays, but never distinctly keeled, the imbricated lines of growth are finer, and the auri-
cles are comparatively larger. Nor could I detect upon them the fine divaricating striz.

The auricles of our shell may be described as unequal, that of the left valve on the
anterior side projecting, so as to form an angle less than 90°. In the right or flatter
valve, the anterior auricle is longer or projects further than the posterior one, leaving
in the full grown shell a considerable opening, even in those which have exceeded two
inches and a half, and on the edge of the shell on that side are prominent denticles:
four or five of which may be seen in the open space beneath the auricle.

The height of most specimens measuring from the umbo to the ventral margin, is
rather less than the diameter of the opposite direction, although in some specimens
these dimensions are reversed. The angle formed by the divergence of the rays from
the umbo may be called a right angle, although it sometimes exceeds, while in the
more elongated specimens, it falls short of that size. In some old shells, the anterior
and posterior sides are extended, so as to give a high-shouldered appearance to the
valve; and in all the younger specimens, the comparative size of the auricles is greater
than in the larger shells, indeed, in the pullus state, they are equal to the entire
length, and the shell then is nearly smooth.

Under a lens, fine divaricating striz may be seen diverging or curving over the shell.

This species is stated by the authors of the ‘ Hist. Brit. Mollusca,’ to possess a
great vertical range, from five to one hundred fathoms, while its peculiar province in
the British Seas is between fifteen and twenty-five.

10. Pecten GRAcILis, J. Sowerby. Tab. VI, fig. 5.
PEcTEN GRACILIS. J. Sow. Min. Conch., t. 393, fig. 2, 1825.
— — S. Wood. Catalogue, 1840.
_ — J. Morris. Cat. Brit. Foss., p. 114, 1843.

Spec. Char. Testdé gracili, suborbiculari, compressé vel planiusculd, tenui, costatd ;
costis acutis, angustis, inequalibus, tripartitis, concentricé et tenuissime imbricato-striatis ;
auriculis parvis inequalibus.

Shell suborbicular, compressed or flattened, delicate, thin, and fragile, costated,
ribs sharp and fine, unequal in size, arranged in threes ; finely striated concentrically,
with imbricated and slightly elevated lines of growth, ears small and unequal.

Diameter, 15 inches.

Locality. Red Crag, Sutton, Holywells, and Bawdsey.

38 MOLLUSCA FROM THE CRAG.

This, as yet, I have seen from the Red Crag only, and in that Formation it is by
no means abundant.

Some varieties of P. opercularis seem to approach this so closely, that it is possible
it may be only a modification of that variable species, with more attenuated and
depressed valves than are commonly seen; there are, however, some differences which
must, at least for the present, keep them separated, more especially as there is no
necessity for the imposition of anewname. ‘The variety linearis of that species, in the
form and arrangement of its sculpture, appears to approach the nearest to our shell.

In P. gracilis both valves are much flattened, the right valve rather the more so
of the two; the auricles appear comparatively less than in opercularis, and the rays
are arranged much in the same manner, but rather more numerous, varying from
twenty to twenty-six, generally tripartite or ranged in threes, the centre one the most
elevated and the most sharp, with an intermediate one between the three, so that
every fourth ray, as stated by Sowerby, ‘ Min. Conch.,’ vol. iv, p. 129, is the most
prominent and the most conspicuous; the same disposition of the rays may be
observed in opercularis, var. /imearis, only in that shell, neither the valves nor the
rays are so much depressed. Our shell is ornamented with fine concentric striz, or
raised and subimbricated lines of growth, giving a roughness to the feeling, more than
to the eye, but the same sculpture is present in /inearis.

The most material differences are a greater flatness in the valves, a much
thinner shell, with a slight alteration in proportionate or comparative dimensions, and
smaller auricles; this last may, perhaps, be looked upon as the most distinguishing
character, if they be really distinct, which more numerous specimens than I possess
may perhaps determine.

A shell from the older Tertiaries at Bracklesham, somewhat resembles this in its
graceful and elegant form, and slightly so in the disposition of the sculpture, but it has
more numerous rays, and the imbricated lines of growth are finer.

11. PecrEN pusius 4rocehi. Tab. IV, fig. 3, and Tab. VI. fig. 3.
List. Hist. Conch., lib. iii, p. 1, fig. 29, 1687.

Ostrea pDuBIA. Broc. Conch. Foss. Subap., p. 575, t. 16, fig. 16, 1814.

PECTEN SCABRELLUS. Desh. 2d ed. Lam., t. vii, p. 161.
= — Bast. Bord. Foss., p. 73, 1825.
a — Goldf. Pet. Germ., t. ii, p. 62, t. 95, fig. 5.
-— — Duyard. Mem. Geol. de France, p. 270.
— a Bronn. Leth. Geog., ii, p. 917, t. 39, fig. 17, a—e, 1838.
— — Grateloupe. Cat. Zool. des An. Vert. et Invert. Bord., p- 58, 1838.
— — Phil. En. Moll. Sic., vol. ii, p. 60, 1844.
— municatus? Risso. Princ. Prod. de l’Bur., t. iv, p. 304, 1826.
— VENTILABRUM? Goldf. Pet. Germ., t. ii, p. 67, t. 97, fig. 2.
— Sowersyr. Nyst. Coq. Foss. de Belg., p. 293, pl. 22, fig. 3, 2, and pl. 22 bis,

fig. 3, a’, 1844,

‘— TUMESCENS. S. Wood. Catalogue, 1840.

BIVALVIA. 39

Spec. Char. Testa suborbiculari, equilaterah, subequivalvi, radiata, radiis \4
—18 sulcatis, plurimum tripartitis, squamoso-denticulatis ; auriculis inequalibus.

Shell suborbicular, equilateral, slightly mequivalved, with 14—18 large and elevated
rays for the most part, one large, with a small one on each side, strongly imbricated
ears, unequal, rayed, and squamose.

Diameter, 13 inch.

Locality. Cor. Crag, Sutton, Ramsholt, Sudbourn, Gedgrave.

Red Crag, Sutton, Newbourn, Bawdsey, Walton Naze.

This is by no means rare in the Coralline, but rather more so in the Red Crag; it
is, however, much less abundant than opercularis, though it may generally be
obtained in those localities in which the shells of either Formation are met with in a
good state of preservation.

The valves of this species may be described as equal in size, at least, as far as can
be determined by the disconnected valves, which appear to present a similar amount
of convexity, although a specimen of the left valve may occasionally be seen a little
more tumid or deeper than the right. The rays are fewer than in PL. opercularis, never
exceeding eighteen, while they have sometimes not more than fourteen, but the general
amount is the mtermediate number ; these are tripartite, and about an equal width with
the spaces between them; the centre ray is much larger than the one on each side of
it, and is covered with large and prominent squame or imbrications, while the smaller
rays are also scabrous, but have more numerous and smaller squame, not correspond-
ing with those upon the larger ray as if they were not formed at the same time by the
reflexed edge of the mantle. The spaces between the rays in the young shell are
naked or free from longitudinal striz, which, however, become ornamented as the
shell increases with from one to three rough and radiating scabrous lines. The
length of the shell in most specimens is equal to the height, but when it deviates
from this regularity it is in the direction from the anterior to the posterior side, which
becomes greater than from the umbo to the ventral margin. Its most distinguishing
characters appear to be the inequality of the auricles, the anterior one bemg much
larger than the posterior, particularly in its young state, and much exceeds the
differences observable in P. opercularis. The spread of the auricles at the liga-
mental edge equals 3-5ths the diameter of the shell, while in some small specimens
the hinge area is comparatively larger. On the right valve beneath the anterior
auricle, as in the last species, are some prominent denticulations, and the exterior
of the shell is also ornamented with fine divaricating striz, visible only with the aid
of a magnifier.

One variety of what I have considered as the young of this species, is rather
peculiarly ornamented on the left valve, having every third ray more especially
covered with large and elevated imbrications, while the two intermediate ones are
nearly smooth upon the outer edge (t. vi, fig. 3).

40 MOLLUSCA FROM THE CRAG.

12. Pecten Istanpicus, Miller, Tab. V, fig. 1.

Proten Istanpicus. Mill. Zool. Dan. Prod., p. 248, No. 2990, 1776.
= = Chem. Conch. Cab., vii, p. 314, pl. 65, figs. 615-16, 1782.
— = Brown. Ilust. Conch. Gr. Brit., pl. 33, fig. 3, 1827.
Wea as Flem. Brit. An., p. 385, 1828.
== — Desh. 2d ed. Lam., vii, p. 145, 1836.
= — Gould. Invert. Massach., p. 133, fig. 87, 1841.
= — Miller. Ind. Moll. Green., p. 16, 1842.
a — G. Sow. Thesaur. Conch., vol. i, p. 75, pl. 17, figs. 159-160, 1843.
== — Dekay. Nat. Hist. New York Zool., p. 173, pl. 11, fig. 206, 1843.
_ _— Lovén. Ind. Moll. Scand., p. 30, 1846.
— — Chenu. Conch. Ilust. Pecten., pl. 32, figs. 1—4.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 303, 1849.
— — Middendorf’. Mem. de l’Acad. des Sci. St. Petersb., p. 526, t. 12,

figs. 7-8, 1849.
== — G. B. Sow., Jr. Thesaur. Conch., vol. i, p. 75, pl. 17, figs. 159—161,
1847.

OstrEA Istanpica. Gmel. Syst. Nat., p. 3326, 1788.
— os Turt. ed. Linn., vol. iv, p. 267.
= — Shaw. Zool. Misc., vol. xxiii, t. 978, 987.
— — W. Wood. Ind. Test., p. 49, pl. 10, fig. 21, 1825.
— CINNABARINA. Born. Mus. Ces. Vind., p. 103, 1780.
— —_ Dillwyn. Desc. Cat. Rec. Shells, p. 256, 1817.

Pecten Prati. Conrad. Amer. Mar. Conch., p. 12, pl. 2, fig. 2, (fide Gould).

Ency. Method., pl. 212, fig. 1.
Lister. Hist. Conch., pl. 1057, fig. 4.

Spec. Char. Testa suborbiculari, equilaterah, convewiusculd, subequivalvi, radiata,
radiis numerosissimis, bisulcatis, scabriusculis ; auriculis inequalibus.

Shell suborbicular, equilateral, slightly convex, subequivalve, covered with nume-
rous close-set, somewhat scabrous bisulcated rays or costulated strie; auricles
unequal.

Locality. Clyde Beds.

Recent, Scandinavia, Greenland, and North American Seas.

This handsome shell is rejected by British Conchologists, as a living inhabitant of
our own Seas, it must necessarily, therefore, fall into the hands of the British
Palzontographist, as a fossil species, it being abundant in the Clyde Beds. Dead
valves have been dredged up in the Scottish and Zetland Seas, from depths varying
from thirty to one hundred fathoms.

It is, essentially, a Boreal species, and is found living upon the Banks of New-
foundland, where it is said by Dr. Gould, to be the favorite food of fishes. I have
not as yet seen a specimen from any of the three Formations into which the Crag has
been separated, although fragments of what may belong to this species have been
found in the Mammaliferous Crag, at Bramerton, and what were considered to

BIVALVIA. 4]

have been P. Princeps, by Woodward, were, probably, only portions of specimens
of this shell which sometimes attains a magnitude of four inches in diameter, a size
that might well lead to such an error.

Our figure is taken from a magnificent specimen found in the beds of the Clyde,

and now in the Museum of the Geological Society, presented by James Smith, Esq.,
of Jordan Hill.

13. PECTEN vARIUS, Linnaeus.
OstreA varta. Linn. Syst. Nat., ed. 12, p. 1146, No. 199, 1767.
— Poli. Test. Sic., vol. ii, p. 163, t. 28, fig. 10, 1793.
— — Don. Brit. Shells, vol. i, pl. 1, fig. 1, 1799.
— _ Shaw. Nat. Miscel., vol. 23, fig. 993.
ee, — — Mawe. Linn. Conch., pl. 14, fig. 4, 1823.
— —_— W. Wood. Ind. Test., p. 50, pl. 10, fig. 31, 1825.
— Burrow. Elem. Conch., p. 144, pl. 9, fig. 2, 1815.
PECTEN vaRIus. Chem. Conch. Cab., vii, p. 331, pl. 66, figs. 633, 634, 1782.
a — Crouch. Int. Lam. Conch., p. 12, fig. 4, 1827.
a — Brown. Must. Conch. Gr. Brit., pl. 33, fig. 4, 1827.
—_— — Phil. En. Moll. Sic., vol. i, p. 84, 1836.
— — J. Smith. Mem. Wern. Soc., vol. viii, p. 46, 1838.
_— — G. B. Sow. Conch. Man., fig. 171, 1843.
— — Id. Thesaur. Conch., vol. i, p. 76, pl. 19, fig. 214, 218, 1847.
_ — Thorpe. Brit. Mar. Conch., p. 118, 1844.
— — Phil. En. Moll. Sic., vol. ii, p. 58, 1844.
— — Lovén. Ind. Moll. Scand., p. 30, 1846.
— — Alder. Cat. Moll. North. and Durh., p. 77, 1848.
— ae Forb. and Hanl. Hist. Brit. Moll., vol. 2, p. 273, pl. 50, fig. 1, 1849.
— monotis. Dacosta. Brit. Conch., p. 151, pl. 10, figs. 1, 2, 4, 5, 7, 9, 1778.

Spec. Char. Testd rotundato-ovata, equivalvi, equilateral, radiata ; rudiis 26—30,
subcompressis, sguamoso-scabris ; auriculd alterd minima.

Shell roundedly ovate, equivalve, equilateral, ornamented with 26—30 subcom-
pressed rays, which are covered with squamose imbrications ; ears unequal.

Loculity. Clyde Beds. Recent, North Seas, Britain, and Mediterranean.

This is given by Philippi, as a living species in the Mediterranean, and enumerated
by Lovén, as an inhabitant of the Coast of Scandinavia; but it has not yet, that I am
aware of, been found in either of the three deposits of the Crag. As it is undoubtedly
a fossil, in the Clyde Beds, and found frequently in the upper Tertiaries of Sicily, it
may, probably, yet be discovered in the Red or Mammaliferous Crag in our own
country. It would not, however, be here introduced simply upon such anticipation,
but it is claimed as one of the fossils of our upper Tertiaries.

42 MOLLUSCA FROM THE CRAG.

Lima,* Bruguere, 1797.

Praciostomus. Llwyd. 1698.

Raputa. Chem. 1784.

Guaucus and GLaucoperRMA. Poli, 1795.
OstreEa (sp.). Linn.

Manvtettum. Bolten, 1798.

PEcTEN (sp.). Mont.

Puaciostoma. J. Sow. 1814.

Giaucton. Ohken. 1815.

Limatuta. S. Wood. 1840.

Limuta. D’Ord. sec. Gray.

Gen. Char. Shell ovate, equivalved, generally oblique, inequilateral, and gaping
at both sides; sometimes closed and equilateral, externally costated or striated,
radiating from the umbo; often rough and squamous like a file. Hinge area extended
into auricles, bipartite; cartilage occupying the central or triangular portion;
ligament more external and linear. Palleal impression entire, that by the adductor
muscle large, ovate, and eccentric.

The animal of this genus has the lobes of the mantle disunited, the margins frmged
with long tentacular filaments, and without siphonal tubes. A small compressed foot
furnished with a byssal groove.

Some species approach very closely to those of the genus Pecten, in being equi-
lateral, and enclosing the animal within the shells when they are brought together ;
in others, the shells gape widely, both on the anterior and posterior sides, and the
animal is too large to be covered by the valves. _ A subgenus was proposed by myself,
for those species which are equilateral and closed (under the name Limatula) ; but
recent examinations of the animals of both sections are said not to present differences
sufficient to justify generic separation. They are, therefore, here united.

The name of Limea was proposed as a genus for those species which are furnished
with teeth or crenulations upon the hinge margin on each side of the cartilagmous
pit, and the name Limoarca was also given in consequence to the same section, but
this character alone, it is to be feared, is not sufficient for generic separation ;
specimens of Lima subauriculata in my own cabinet, are in like manner supplied with
minute crenulations. Dr. Loven, however, states the animal of his Zimea Sarsii to
have the margin of its mantle destitute of tentacular appendages. Species, probably
belonging to this genus, from the older Secondary Formations figured and described
under the name of P/agiostoma, have been long known, and were abundant in some of
the older periods. In those shells the gape or opening appears to have been on the
rounded or posterior side, on which, in the recent shell, is placed the large adductor
muscle, while the foot, the organ that secretes the byssus, is on the anterior side,
which appears to have been capable of being quite closed, the opening, therefore, was

* Etym. limus crooked, oblique; lima? a file.

BIVALVIA. 43

not, probably, for the organ of attachment, and as in the recent species, their shells
vary much in those characters, the secondary fossils were most likely of this genus.

1. Lima Exiuis, S. Wood. Tab. VII, fig. 6, a—e. “
Lima exiuis. S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 233, Sup., pl. 3, fig. 1,
1839.
— — S. Wood. Catalogue, 1840.
-— — Morris. Cat. of Brit. Foss., p. 111, 1843.

Spec. Char. Testa ovata, valdé obliqud, depressd, fragili, exili, utroque latere hiante ;
costato-striatd, striis 25-35 asperimis, undulatis ; cardinis obliqui area angusta ; auriculis
minimis equalibus.

Shell ovate, very oblique, somewhat depressed, slender, and fragile, gaping largely
on both sides; striated or costated, strie 25-35, rough, irregular and unequal,
cardinal area large, oblique ears, rather small and equal.

Longitudinal diameter, 1% inch. Height, 13 inch.

Locality. Cor. Crag, Ramsholt, Sudbourn.

Red Crag, Walton Naze.

This elegant shell does not appear to have been very scarce in the Coralline
Crag Sea, having myself procured a dozen specimens, most of which were from one
locality, Ramsholt ; it is also occasionally found in the more tranquilly deposited portion
of the Red Crag at Walton Naze, but its fragility in proportion to size is against
its preservation in that deposit, as even in the older formation, specimens are not often
obtained in a perfect state.

Messrs. Forbes and Hanley have introduced this fossil into their synonyma of
LI. hians, considering it only as a variety of that species, to which opinion I am not
willing to assent as a marked and striking difference is presented by my fossils
sufficient by the ordinary mode of valuation in specific distinction to justify a
separation. It somewhat resembles L. izfuia, but is flatter and undeserving of that
name, and a shell in the British Museum called Z. scadrel/a, approaches it in some
respects, but that is also more inflated, and is probably a variety of the znflata; I
have therefore retained it as distinct, bemg intermediate between the British and
Mediterranean species, approaching rather nearer to the latter than to the former.

It may be more particularly described thus: the form is irregularly ovate,
very oblique, gaping on both sides, and covered with raised and slightly undulating
costulated striae, these are rough or scabrous, at nearly regular distances, covering
im some specimens the entire surface, but generally a small space is left naked
on the anterior side; in LZ. hians the striz are less regular, thicker on the
posterior side, larger and more dissimilar on the anterior, in this they are rather
more distant upon the posterior half; the comparative dimensions of this are very
different, taking the height at 15 inch from the umbo to the ventral margin, the
diameter in the opposite direction is equal to 14 inch, but in /zans the height is at

44 MOLLUSCA FROM THE CRAG.

least one third greater than the length; the hinge line in this is more oblique, the
ligamental area broader and more shallow, with a smaller gape on both sides. Two
forms of the British shell have been figured by Professor Forbes in the ‘ Mag. Nat.
Hist.,’ one of which is less elongated than the other, and more nearly approaches
our shell, but there is still apparently a sufficient difference to keep them separated.

2. Lima HIANS, Gmelin. Tab. VII, fig. 2, a—e.
OsTREA HIANS. Gmel. Syst. Nat., p. 3332.
os — Turt. ed. Linn., vol. iv, p. 273, 1806.
— — W. Wood. Ind. Test., p. 51, pl. 11, fig. 53, 1825.
Lota TENERA. Turt. Zool. Journ., vol. ii, p. 362, t. 13, fig. 2 (not tenera Chem.).
= — Brown. Ilust. Conch. Gr. Brit., pl. 31, figs. 8, 9, 1827.

— Forbes. Malac. Monen., p. 41, 1838.
— — Id. Report on Aigean Invert., p. 182, 1843.
— Phil. En. Moll. Sic., vol. ii, p. 56, pl. 16, fig. 3, 1844.

— unFuatTa. Forbes. Malac. Monen., p. 41, 1838.

— Sarsit. Kréyer, fide Loven.

— vitTrina. Brown. lust. Conch. Gr. Brit., pl. 31, figs. 10, 11.

— rRaGiLis. Flem. Brit. Ann., p. 388, (partly,) 1828.

aS = Id. Crouch. Corn. Faun., pt. 2, p. 37.

— apERrTa. G. B. Sow. Thes. Conch., vol. i, p. 87, pl. 22, figs. 26 & 27, 1847.
— — Thorpe: Brit. Mar. Conch., p. 249.

— tans. Lovén.«Ind. Moll. Scand., p. 32, 1846.

— — Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 268, pl. 52, figs. 3—5, and

pl. R (animal), 1849.

— opionea. S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 234, pl. 3, fig. 2, 1839.
Lim. Forbes. Mag. Nat. Hist., vol. viii, pp. 593, 594, figs. 63 & 64, 1835.

Spec. Char. Testé oblongo-ovatd, obliqud, valdé inequilaterd, depressd, gracili, costato-
striatd, striis vel radiis numerosis, asperimis, irregularibus, cardine obliquo, area triangulart
lata, auriculis equalibus ; margine denticulato.

Shell elongato-ovate, oblique, very inequilateral, depressed, and slender; striated
with numerous, rough, irregular, and slightly waved striz, projecting beyond the
ventral margin; gaping widely on the posterior side, slightly so on the anterior ;
ligamental area large and triangular, umbones prominent and distant.

Height, \ inch. Length, 6-10ths of an inch.

Locality. Cor. Crag, Ramsholt.

Recent, Britain, Scandinavia, and Mediterranean.

' This appears more scarce as a fossil than the preceding, having as yet obtained

only two specimens, and those both of the same value, and from the same locality,
there is, however, little doubt of its identity with the recent British species.

The form of this shell is comparatively much more elongated than the preceding, and

is somewhat flatter ; it gapes widely on both sides, that on the posterior is particularly

deep immediately behind the hinge line, while the front gape is near the ventral

BIVALVIA. 45

margin; the exterior is covered with numerous irregular striz or striated coste,
rough or scabrous, radiating in an undulating direction, extending from the extreme
edge of the posterior side to the anterior, where, for a small space, it is naked or
destitute of strize, those on the posterior are fine and closer set, becoming larger and
more distant as they approach the anterior, where they are rough and project beyond
the margin. The hinge line is less oblique than in evi/is, and is narrower, which per-
haps it would be, if not a different species, corresponding thus with the more narrow
form of the shell, but the ligamental area is deeper from the umbo inwardly, while the
gape on both sides is larger than in that shell, and the whole contour in this is so dif-
ferent that, judging from the specimens which I possess, they cannot be united without
an extension of variation greater than is generally permitted to species of this genus.
In the recent state, in the more northern parts of the British seas, it attains a greater
magnitude than is given by the dimensions of our fossil, which may not, possibly, be a
full-grown individual, although its gape is wide, a character of the adult shell; it is said
one inch and three quarters is not an uncommon size in the recent British specimens,
whilst those found at Guernsey are less, resembling in this peculiar our Crag fossil.

3. Lima Loscomsu, G. Sowerby. Tab. VII, fig. 1, a—e.
PrcteN FRAGILIS. Mont. (not Chemnitz). Test. Brit. Sup., p. 62, 1808.
Ostrea FRAGILIS. Turt. Conch. Dict., p. 131, 1816.
Lima BULLATA. Turt. (not OstrEa BULLATA, Born.). Brit. Biv., p. 217, t. 17, figs. 4, 5.
ae — Thorpe. Brit. Mar. Conch., p. 114, 1844.
— — Phil. En. Moll. Sic., vol. ii, p. 56, t. 16, fig. 2, 1844.
— Loscompi. G. Sow. Genera of Shells, No. 17, ‘Lima, fig. 4.
— — Reeve. Conch. Syst., pl. 112, fig. 4.
— — G. Sow. Thesaur. Conch., vol. i, p. 86, pl. 22, figs. 20—22.
= — Lovén. Ind. Moll. Scand., p. 32, 1846.
os — Forb. and Hanl. Hist. of Brit. Moll., vol. u, p. 265, pl. 53, figs. 1—3.
= Alder. Cat. Moll. North. and Durh., p. 78, 1848.
— FraGiLis. Brown. Mlust. Conch. Gr. Brit., pl. 31, figs. 6-7, 1827.
Gs — Forbes. Mag. Nat. Hist., vol. viii, p. 594, fig. 65.
— — Id. Malac. Monen. p. 40, 1838.
— — S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 235, pl. 3, fig. 3, 1839.

Spec. Char. Testa tumida, oblique-ovatd, inequilaterd, tenui, fragili ; utroque latere
perparvulum hvante, striata, striis tenuissimis, alternatis, undulatis, cardine obliquo.

Shell tumid, obliquely ovate, inequilateral, thin and fragile ; very slightly gaping
on either side, covered with fine strize, slightly undulating, and alternately larger and
smaller; cardinal area oblique and small.

Greatest Diameter, % of an inch.

Locality. Cor. Crag, Sutton and Ramsholt.

Red Crag, Walton Naze.
Recent, Britain, Norway, and Mediterranean.

46 MOLLUSCA FROM THE CRAG.

This elegant and fragile shell is by no means rare in the Coralline Crag at Sutton,
but rather less so at Ramsholt. Walton Naze is the only locality in the Red Crag
from which I have seen it. There cannot, it is presumed, be any doubt about the
identity of this species, which does not seem to possess even a local variation.

The strize which ornament this shell are sometimes regular in size, but more cities
possess an intermediate smaller one; there is a very slight opening between the valves,
near the hinge line on the posterior side, and the valves do not quite close on the
anterior side towards the ventral margin; hinge line rather short, with a large and
broad ligamental pit projecting inwards ; a subcircular impression by a large adductor
muscle towards the convex or posterior side of the shell.

4. Lima pLicatTuta, S. Wood. Tab. VII, fig. 4.
Lima piicatuta. S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 235, pl. 3, fig. 4, 1839.

Spec. Char. Testa minuté, inequilaterali, obliqué-ovata, compressiusculd ; costato-striatd,
strus 14—16 convexis, scabriusculis; anticé rectd, postice rotundatd ; auriculis valdé
inequalibus ; cardine obliquo; ared hgamenti minutd ; in auriculis dentibus obtusis.

Shell small, inequilateral, obliquely ovate, slightly compressed; costated or
striated ; strize 14—16 rounded and somewhat scabrous; anterior side straight,
posterior rounded; auricles very unequal; hinge line oblique; ligamental area
small, with an obtuse tooth in the centre of the auricles.

Longest diameter, th of an inch.

Locality. Cor. Crag, Sutton.

About a dozen specimens of this shell are in my cabinet, but none of them in very
perfect condition ; and I have not seen other specimens, since the publication of it in the
‘Mag. Nat. Hist.,’ to give further assistance in its elucidation. It appears, however,
to present characters differimg from any other species with which I am acquainted,
and it must, for the present at least, be considered as distinct, and may be more
particularly described thus. .

The shell is very oblique; the anterior straight, sloping from the umbo with a
scarcely perceptible auricle on that side; while the posterior is not only rounded, but
has a comparatively large and projecting ear: it appears to have been able almost to
close the valve, or at least to have had a very slight gape, as the edge of the shell
nearly touches ‘all round when laid upon a flat surface with its exterior uppermost ; the
rays are rounded, slightly scabrous, and numbering about 17 or 18, and these are.
somewhat broader than the spaces between them, which are prettily ornamented with
elevated ridges, giving it a cancellated appearance. The hinge is rather peculiar,
the central depression or pit being small and very oblique; and on each side in the
middle of the auricles is a tooth-like projection with a corresponding depression in the
opposite valve; a similar character may be observed in other species of this Genus,
where interlocking prominences and depressions are formed by the animal as an

BIVALVIA. 47

additional security against any injurious lateral movement of the valves. It
appears to differ from Z. plicata of the Touraine Beds in not being so elongated,
and in having a broader ligamental area; and from Z. odliqua, of the Paris Basin, in
somewhat similar characters.

5. LIMA SUBAURICULATA, Montague. Tab. VII, fig. 3, a—e.
PECTEN SUBAURICULATA. Mont. Test. Brit. Sup., p. 63, t. 29, fig. 2, 1808.
_ — Flem. Edinb. Ency., pl. 205, fig. 12.
OsTREA SUBAURICULATA. Turt. Conch. Dict., p. 131, 1816.
—_ W. Wood. Ind. Test. Suppl., pl. 2, Ostrza, fig. 5.
LIMa —~ Turt. Brit. Biv., p. 218, 1822.
— _ Flem. Brit. An., p. 388, 1828.
— —~ Thorpe. Brit. Mar. Conch., p. 114, 1844.
— G. Sow. Thesaur. Conch., vol. i, p. 84, pl. 22, fig. 23.
— _ Phil. En. Moll. Sic., vol. ii, p. 56, 1844.
— — Lovén. Ind. Moll. Scand., p. 32, 1846.
= — Alder, Cat. of Moll. North. and Durh., p. 78, 1848.
— — Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 263, pl. 53,
figs. 4, 5, 1849.
— suicata. Brown. Illust. Conch. Gr. Brit., pl. 31, figs. 4, 5, 1827.
— — Miller. Ind. Moll. Greendl., p. 16, 1842.
OsTREA NIVEA. Broc. Conch. Subap., p. 571, t. 14, fig. 14, 1814.
Lima — Risso. Europ. Merid., t. iv, p. 306, 1826.
— “— Desh. in Lyell’s Princ., Ist ed, vol. ii, App., p. 12, 1833.
— — Nyst. Rech. Coq. Prov. d’Anv., p. 17, 1835.
— — Phil. En. Moll. Sic., vol. i, p. 78, 1836.
— — WNyst. Coq. Foss. de Belg., p. 281, pl. 21, fig. 4, 1844.
— suLtceuLus? Lovén. Ind. Moll. Scand., p. 32, 1846.
— eELoneATA. Forbes. Aigean Invert., 1843, Rep. Brit. Assoc., p. 192.
LIMATULA SUBAURICULATA. S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 236, pl. 3,
fig. 6, 1839.
— — Morris. Cat. of Brit. Foss., p. 111, 1843.

Spec. Char. Testd elongato-ovali, equilateral, fragili, convexd, in medio striatd vel
costatd, striis rugosis, sepé obtusé angulatis, mediis binis verticalibus ; cardine recto ; auriculis
aqualibus.

Shell elongato-ovate, equilateral, convex, fragile, and closed all round ; costated or
striated in the centre, becoming obsolete at the sides; strize or coste rugose, sometimes
angulated; hinge line straight; auricles equal.

Length, +; height, } an inch.

Locality. Cor. Crag, Sutton and Ramsholt.

Recent, Britain, Norway, and the Aigean Sea.

Small specimens of this species are by no means rare in the Coralline Crag at
Sutton; this place and Ramsholt are the only two localities from which it has as yet
been obtained ; and there is no doubt about its identity with the recent British species.

48 MOLLUSCA FROM THE CRAG.

Our shell is not strictly ovate, but more of an oblong form, with the angles rounded
Off ; the sides being somewhat straight, or of very gentle curvature, it is tumid and
thin; the whole of the ribs being visible on the inside, they occupy the centre of the
shell, and are distributed over about half the surface, two or three of the middle ones
being the most distinct, and these are more conspicuously so on the inside ; umbones
prominent and divergent, leaving a wide ligamental area between them, thereby
enabling the animal considerably to divaricate the valves ; costa obtusely angulated,
rough, but not imbricated, showing distinct lines of growth; hinge-line straight ;
cartilage pit concave, projecting inwardly, forming an angle of 90°, and occupying
nearly half the ligamental area. The shell extends on each side of the umbo into
what are called auricles, the greater part of which space is occupied by the ligament ;
on the inside beneath these auricles the shell is thickened and strengthened by a
prominent ridge, diverging from beneath the umbo towards the sides: in some speci-
mens may be seen the impression of the large adductor muscle inclining towards the
centre; my largest specimens do not exceed half an inch, measuring from the umbo
to the ventral margin, and the transverse diameter about half that size.

A specimen from the Aigean Sea was given to me by Professor E. Forbes, with the
name of ZL. elongata, which so much resembles some of the Crag specimens (fig. 3, c),
that I have introduced the name among the synonyma. In the Aigean shell, which
was obtained from the depth of 100 fathoms, the costated strize are in number
about 20, more distinct and distant on the centre or convex portion, and of course
widest near the margin, not rounded but angulated ; while in the generality of speci-
mens of subauriculata they are rounded, but the same characters of sharpened coste
are visible in some of the Crag specimens, and there is not a distinction between the -
two sufficient, in my opinion, for specific separation ; probably with a large number of
individuals of the A‘gean shell, as much difference might be detected as is exhibited
in my Crag specimens. . .

Upon some of the smaller and most perfect specimens of this species from the
Crag, may be observed a row of fine crenulations, occupying the entire edge of the
hinge-line (fig. 3, 2), being a miniature representation of what has been considered a
good generic character; these are, however, so small as to be of little service for the
ordinary purposes in which the teeth or prominent portions of the shell about the
hinge are employed by the animal.

Lima ovata, S. Wood.. Tab. VII, fig. 5.
LrmatuLa ovata. S. Wood. Mag. Nat. Hist., New Series, vol. iii, p. 235, pl. 3, fig. 5,
1839.

Spec. Char. Testd minutd, ovatd, equilaterd, undique clausd, inflatd ; in medits
costatis, utrinque obsoletis, costis angulatis circa septem; cardine recto, foveo ligamenti
trigond, concava.

BIVALVIA. 49

Shell small, ovate, equilateral, tumid, and closed, costated, central portion with
7-9 angulated ribs, becoming obsolete or disappearing on the sides; hinge margin
straight, with a trigonal and concave pit for the cartilage.

Height, 3,. Length, 25. Depth of united Valves, +; of an inch.

Locality. Cor. Crag, Sutton.

This pretty little shell is very abundant in the Coralline Crag, at the above
locality.

It appears to be quite distinct from the preceding, and differs in several
characters, and there is no species recent or fossil known to me to which it can be
assigned.

It has about seven angularly formed coste, which occupy the central portion
of the dorsal area, beyond these are faint traces of strie, and in well preserved
specimens the shell is semi-transparent, rendering these ribs visible in the interior, and
giving about half a dozen rough crenulations to the ventral margin of the shell.

The ligamental area is large, and the central pit diverges from the umbo under an
angle of about 80°, muscular impression subcentral and ovate. It differs from any of
the specimens of the preceding species of the same size, in being thicker and more
regularly ovate, the ventral margin is more pointed, the sides are less straight,
while the costz are more prominent and distinct. I have not seen L. sulculus,
Leach and Lovén, but the descriptions do not accord with our Crag shell, as it wants
the “‘mediis binis verticalibus,’ mentioned by the latter author, but which character
may be seen in specimens of L. subauriculata.

PInNNA.* Linneus.

Pinna. Arist. Aldrov. List. Linn. Lam., Se.
PENNARIA. Browne, 1756.

Cuim=ra et CoIMmRopERMA. Poli., 1795.
Perna. . Adans, 1757..

Oxysma? Rafinesque, 1819.

CURVULA. Id.

Arrmna. Gray, 1840.

Generic Character. Shell equivalved, inequilateral, oblique, triangular or wedge-
shaped, generally thin and fragile; umbones terminal, hinge rectilinear, without teeth ;
anterior margin sinuated and slightly gaping for the passage of a byssus; posterior
truncated. Impression by the mantle entire ; ligament internal.

Animal triangular, in conformity with the shape of the shell; its mantle open or
disconnected on all sides, except the dorsal edge, while its lobes line the whole
interior of the valves; the lobes are ornamented with a double row of tentacular

* Etym. tivva, Arist., a kind of Pearl Oyster.

50 MOLLUSCA FROM THE CRAG.

cirrhi or fringes round their posterior part; and a single row upon the anterior ;
foot somewhat small and slender, furnished with a byssal groove; no projecting
siphonal tubes.

Animals composing this genus have their valves particularly thin, considering
their dimensions, which sometimes attain considerable magnitude. In the recent state
they are generally of a brownish or horny colour, which with their angular form have
obtained for them, in France, the vulgar name of jambonneaux, or little hams. The
shell gapes slightly at the anterior part near the beaks, through which is protruded a
set of fibrous threads or byssus, so long as to have been occasionally manufactured
into gloves and stockings. They are exclusively marine, having a range in depth
somewhat considerable, living often in sand or mud, with their beaks or pointed
extremity buried deep in the ground ; sometimes fixed to submarine bodies, by means
of the byssus, which it is said to be capable of displacing at will by the aid of its foot.
The two valves are closely united or soldered, as it were, together, along the dorsal
edge, and are incapable of much expansion, but they gape widely at their larger or
posterior extremity, opposite the beak.

The number of recent species is somewhat limited, although they have a very wide
geographical distribution, being found in most parts of the world, and the fossil species
date as far back in time as the Oolitic Period, from which Formation there is one
strongly resembling an existing form.

1. PINNA PECTINATA (?) Limneus. Tab. VIII, fig. 11.
Pinna PEctinatTa. Linn. Syst. Nat., ed. 12, No. 264, p. 1160, 1767.
_— _ Turt. Brit. Biv., p. 223, pl. 19, fig. 1, 1822.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 255, pl. 43, figs. 1, 2, and
pl. 53, fig. 8, 1849.
— nGens. Mont. Test. Brit., pp. 180, 583, and Sup., p. 72.
= — S. Wood. Catalogue, 1840.

A few fragments or imperfect specimens of a species of this genus have been
obtained by myself from several localities in the Coralline Crag, but they are not in
sufficiently good condition for instituting a fair comparison; what there is of them
seem to present recognisable characters, and to correspond with those of the above-
named recent species, and may, at least for the present, be considered as identical.
In my Catalogue it was placed under the name of P. zmgens, Mont., which the authors
of the ‘ Hist. of Brit. Moll.’ have determined to be only a variety of pectinata ; the
spiny or scaly sculpture of that shell being generally removed by abrasion as it
advances in age.

In the small portion of what remains of our fossil, the radiating lines cover about
half the shell, or from the dorsal edge extending into the middle of the valve; the
ventral portion being sinuated and much thickened at the edge where the presumed
byssus protruded, and the exterior is on that side ornamented with subconcentric or

BIVALVIA. 51

wavy undulations, like those visible upon the recent shell. This species, in the recent
state, is one of our largest bivalves, and Montague says they are not uncommonly
a foot in length. The specimen to which our fragment belonged, probably did not
exceed half that size. The same authority states, p. 181, ‘‘ We discovered a bed
of these shells in Salcomb Bay, in Devonshire, where they are called by the fishermen
French muscles or scallops. They lie on a gravelly bottom, covered with mud and
long sea-weeds, and are only to be got at particular times when the sea recedes further
than usual.” This shell in its living state is of a sort of double composition, the thin
and broadest, or outer portion, being of a brown and somewhat horny texture, while
the thickened lining, or anterior portion, is of a nacreous substance, composed of
fibrous filaments, causing the shell in the fossil state to separate readily at that part in
a transverse direction ; and pieces of this ‘fibrous shell’ are often met with in the
Coralline Crag at Sutton, separating like finely attenuated glassy filaments.

Avicuta,* Klein, 1753.

Prerta. WScopoli, 1777, sec. Gray.
RipaRtz (sp.). Gevers, 1787. Id.
MarGaritirera (sp.). Humph., 1797.
Anontca. Oken., 1815.

PERLAMATER (sp.). Schum., 1817.

Generic Character. Shell equilateral, imequivalve, oblique; upper or left valve
the larger or more tumid; the lower or right valve with an opening for the passage of
a byssus; surface sometimes smooth, at others ornamented with squamose appendages,
or furnished with radiating cost; hinge-line rectilinear, often with the posterior
extremity prolonged into the form of an extended wing; one obtuse tooth in each
valve ; paleal impression without a sinus ; ligament external.

Animal triangular; the edges of the mantle disunited, and the margins fringed
with small tentacles; foot small, subcylindrical, beneath which is a byssal groove ; no
syphonal tubes.

1. AVICULA TARENTINA ? Lamarck.

Mytitus HirunDo. Linn. Syst. Nat., ed. 12, p. 1159 (in part).
— — ? Poli, Test. Utr. Sic., vol. ii, p. 221, t. 32, fig. 17, 1795.

AvicuLa HirunDo. Turt. Brit. Biv., p. 220, pl. 16, figs. 3, 4, 1822.
— acuruata. Risso. Hist. Nat. des Princ. Prod. de l’Eur., t. iv, p. 308, 1826.
— Aruantica. Brown. Ilust. Conch. Gr. Brit., pl. 10*, fig. 6, 1827.
— Awyentca. “Leach.” Id. - - pl. 31, fig. 3.
— Tarentina. Lam. Hist. des An. S. Ver., t. vi, p. 148, 1818.
a= — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 251, pl. 42, figs. 1—3,

and pl. S., fig. 4, 1849.

* Etym. dvicula, from its resemblance to a Bird’s wing.

52 MOLLUSCA FROM THE CRAG.

Two fragments were found by myself in the Coralline Crag at Gedgrave, which
belong undoubtedly to this genus, and as far as can be determined from their muti-
lated condition, appear to be of the above-named species; they are introduced here
provisionally until better specimens be procured than what I possess: my specimens
of the left valve have an obtuse tooth immediately under the beak within the
ligamental margin, and are beautifully nacreous within. ‘The area for the ligament
appears somewhat larger than is shown by the recent shell.

Mytitus,* ZLinneus, 1758.

Mytutus. Rondelet, 1555, sec. Herrm.
Muscuuus. List. 1687.
Mitutus. Browne, 1756.
PERNA (sp.). Adans, 1757.
Id. Schum., 1817.
CALLITRICHE et CALLITRICODERMA. FPoli., 1795.

Generic Character. Shell equivalve, inequilateral, oblique, elongate, wedge-shaped
or subtriangular, more or less tumid, sometimes thin and semitransparent, occasionally
thick and opaque: in the recent state covered with an epidermis: umbones acute,
terminal; hinge slightly denticulated; surface generally smooth, sometimes striated.
Ligament linear, internal. Muscular impressions two, unequal, anterior one near the
umbo, elongate, posterior one suborbicular near the posterior part of the ventral
margin: palleal impression without a sinus and rather obscure.

Animal elongate, with the lobes of the mantle partly fringed, disconrtected except
at the posterior, where there is a short anal siphon: adductor muscles very unequal ;
a cylindrically formed foot furnished with a gland and groove.

Animals belonging to this genus are inhabitants of salt-water or estuaries, and are
generally very littoral in their habits; the common Mussel, as is well known, is more
often found where it is deserted by the retiring tide, but some are inhabitants of the
sea at a considerable depth. The living species are found in various parts of the
world, and in the fossil state have been obtained as low in the secondary series as the
Cornbrash.

Mytitus EDULIS, Linneus. Tab. VIII, fig. 9, a—e.

MuscuLvs suscmruteus. List. Hist. Conch., lib. iii, fig. A, 200, 1687.

Mytitus EpuLIS. Linn. Syst. Nat., ed. 12, p. 1157, No. 253, 1767.
—_ — vuLGaTisstmus. Chem. Conch. Cab. viii, p. 169, t. 84, figs. 750, 751, 755.
— PELLUCIDUS. Penn. Brit. Zool., ed. 4, vol. iv, p. 112, pl. 63, fig. 75.
— vuLeaRis. Da Costa. Brit. Conch., p. 216, pl. 15, fig. 5, (left-hand fig.)
— INcurvatus. Penn. Brit. Zool., pl. 64, fig. 74.
— ELEGANS. Brown. Illust. Conch, Gr. Brit., pl. 29, figs. 14, 15, 1827.

* Etym. puridos (deriv. a pis, as vauridos a vais).

BIVALVIA. 53

Mytitus Fuavus. Polk. Test. Sic., vol. ii, p. 207, pl. 32, fig. 4, 1795.

—_— SaAGITTATUS. Id. - - - 208, - figs. 2, 3.

_ UNGULATUS. Id. - - - 209, - fig. 5.

— GALLOPROVINCIALIS. Desh. 2d ed. Lam., t. vii, p. 46.

— ABBREVIATUS. Id. - - - p. 47, No. 30.
— RETUSUS. Id. - - - p. 48, - 31.

—_ BOREALIS. Dekay. Nat. Hist. New York Zool., p. 182, pl. 13, fig. 222.
_ pitatatus. W. Wood. Ind. Test. Sup., pl. 2, Mytiu., fig. 2.
— SUBSAXATILIS. Williamson. Mag. Nat. Hist., 1834, vol. vii, p. 354, fig. 48, a—d
— ANGULATUS. Alder. MSS., fide Williamson.
— SOLITARIUS. Rev. W. Mark. MSS, Id.
_ noratus. Dekay. Nat. Hist. New York Zool., p. 182, pl. 13, fig. 223, 1843.
— ANTIQUORUM. J. Sow. Min. Conch., t. 275, figs. 1-3, 1821.
— — Desh, 2d ed. Lam., vii, p. 54, 1836.
—_ Nyst. Rect. Coq. Foss. Prov. d’Anv., p. 17, No. 66, 1835.
— — Phil. En. Moll. Sic., vol. i, p. 73, and vol. ii, p. 53.
— — Nyst. Coq. Foss. de Belg., p. 267, pl. 21, fig. 1, a—é.
— — Basterot. Mem. Geol. des Env. de Bord., p. 78, 1825.
a — Woodward. Geol. of Norf., p. 44, t. 2, fig. 20, 1833.
— ALH=ForRMIs. J. Sow. Min. Conch., t. 275, fig. 4, 1821.
— — Woodward. Geol. of Norf., p. 44, 1833.
oa AFFINIS. Bean. MSS. (not Sowerby).
a PLEBEIUS? Dubois de Montp. Conch. Foss. de Wolhyn. Podol., p. 69, pl. 7;
figs. 26-28, 1831.
~ EpuLIs. Brocchi. Conch. Foss. sub. Apen., p. 584, 1814.
— _ Bast. Mem. Geol. des Env. de Bord., p. 79, 1825.

.

Spec. Char. Testé elongato-trigonuld, levigatd ; anterius curvd, subangulatd ; posterius
retusa ; versus basim tumidd ; dentibus tribus vel quaternis.

Shell elongate, of a subtrigonal form, smooth, anterior part curved, subangulated,
posterior obtuse, tumid towards the base, hinge with three or four denticles.

Greatest diameter, 4 inches.

Locality. Red Crag, Sutton, Bawdsey, Ipswich.

Mam. Crag, Bramerton, Bridlington.
Recent, Mediterranean, Britain, Scandinavia, and North America.

The true edible species is first seen in the Red Crag Deposit, and is found in some
places, as might be expected, in great abundance, but the specimens have become so
thin and fragile, as to be with difficulty procured entire.

What is considered as the normal form of this species, by Messrs. Forbes and
Hanley, is that variety which has been erected into a distinct species by Mr.
Williamson, under the name sw4savatilis. Yn this the shell is more angular, and the
posterior portion becomes broader, its solitary habits giving free scope to an expansion
at that part, and enabling it to assume what may be called its natural shape. This
variety has not been met with by myself in the Red Crag, but it is by no means
uncommon in the deposit at Chillesford which rests upon it, and which probably
belongs to the mammaliferous:or more recent period, and where it is the only

54 MOLLUSCA FROM THE CRAG.

form of this species, the other varieties have all been obtained from the older
formation.

The ligament of this is placed within the margin of the shell, although slightly
visible externally, when the valves are closed, it extends the entire length of the dorsal
edge, and a considerable scope is given to the dilatation of the valves; four small
teeth are placed on the anterior side of the umbo interlocking each other; these teeth
are always visible, though somewhat variable in their character, the anterior one being
sometimes the larger, and vice versd. In the increase of the valves a slight curvature
is given to the umbo by the retrocession or retreating of the ligament: while fresh
layers are deposited on the anterior margin, three small ridges are left upon the
exterior, indicating the form and position of these teeth, which are produced internally
by the indentures of the exterior. A small but deeply-seated muscle mark is visible on
the anterior side, or immediately beneath the umbo, and a large subcircular one a little
within the posterior part of the ventral margin. Mr. Alder says, “no species under-
goes a greater degree of variation from locality than the common Mussel. For its
full development, a mixture of fresh with salt water appears to be necessary, it is
therefore met with in the greatest perfection at the mouths of rivers. In such
localities the typical form of the species is to be found, and when left undisturbed
usually forms large beds. On the more rocky and exposed parts of the coast it
assumes a stunted appearance, running into the varieties of form mentioned above,
always small on the exposed surface of rocks, but attaining a larger size in hollows
and crevices.” a

In the Estuary Deposit of the Eocene Period, at Colwell Bay, as well as upon the
opposite side of the Solent at Hordwell, is found a species of Mussel (17. afinis, ‘Min.
Conch.,’ T. 532, fig. 1), which very much resembles the var. pellucidus of this species,
but it is decidedly more carinated, and wants the denticles so conspicuous in the
common edible Mussel, near the umbo; and notwithstanding the extraordinary range
in variation assumed by this species, there is, I think, no doubt of the two shells being
specifically distinct ; a specimen from Bridlington, with this name, was obligingly sent
to me for description by Mr. Bean, but there is every reason to believe it is only a
variable form of our common Protean shell.

It is, in general, of littoral habits, being often found in the living state where left
dry by the retiring tide, and as such, indicative of shallow water, although it is
occasionally met with at considerable depth. Its geographical range is very great,
being undoubtedly an inhabitant of the Mediterranean, as well as of the coast of the
United States of America, and in both of which extremes of longitude it appears to
be subject to the same variable character. ‘This is a long known species, descriptions
or figures of the recent shell having been given by almost every author, ancient or
modern, who has ventured to describe a shell; and in order to show its range in
variation, a list of names is introduced, under which it has been described, pre-
suming all to belong to one and the same species, a single example of each name
being considered sufficient for the living shell.

BIVALVIA. 55

2. MytiLus HESPERIANUS, Lamarck. Tab. VIII, fig. 10.
Myritus HESPERTANUs. Lam. Hist. des An. Sans. Vert., t. vi, p. 127, 1819.
— — Desh. 2d ed. Lam., t. vii, p. 48, 1836.
— — Payr. Cat. Moll. Cors., p. 68, pl. 2, fig. 5, 1826.
— pENsATUS. S. Wood. Catalogue, 1840.

Spec. Char. Testé elongatd, obliqud, incurvaté densatd, crasséd; margine dorsal
arcuata.

Shell elongate, oblique, incurved, thick and heavy ; dorsal margin convex.

Greatest Diameter, 24 inches.

Locality. Cor. Crag, Sudbourn. Recent, Mediterranean, and Coast of Spain.

Two specimens only of this shell have yet come into my possession, and these are
both of the right valve, and as they are all that I have seen, it does not appear to have
been abundant during the Cor. Crag period. Fragments of a very thick Mussel,
indicating a considerable curvature, and which I presume to belong to this species,
are not unfrequently met with in various parts of the Red Crag; and as they have
undergone a considerable deal of bouldering, may possibly have been washed out of
the deposit of the antecedent period. I have given it therefore as a certain inhabitant
of the older formation only.

It appears to present characters different from any of the varieties of the common
edible Mussel, sufficiently it is presumed to entitle it to be considered a distinct species.
The variety called MZyt. incurvatus, Mont., approaches nearest in form, but the dorsal
margin is never so convex as in our shell, and the specimens I have seen are much
thinner. The Crag shell is very thick, more especially in the narrow part near the
beaks, and the anterior side curves inwardly, while the dorsal and posterior portions are
particularly convex in outline ; the umbones are eroded, and the outer part of the shell
near the beaks is so thin as to show the white lining through it, while towards the
ventral portion the shell is of a deeper colour, as described by Payraudeau. My
specimens are destitute of hinge-teeth, but their probable habitat in deep and more
tranquil water may have rendered such unnecessary, and they may have thus become
obsolete.

Mopio1a,* Lamarck, 1801.

VoLsELLA. Scopoli, 1777, sec. Gray.
CALLITRICHE et CALLITRICHODERMA. Poli., 1795.
Amyepatum. Megerle, 1811.

CRENELLA. Brown, 1827.

BracHypontes. Swains., 1840.

LanIstTEs. Id. 1840.

Mopiorarca. Gray, 1840.

Mopiotaria. Beck, sec. Loven, 1846.
Lanistina. Gray, 1847.

Moptotorsis? Hall, 1847.

* Etym. Modiolus.

56 MOLLUSCA FROM THE CRAG.

Generic Character. Shell equivalve, inequilateral, irregularly and roundedly trape-
zoidal ; valves sometimes smooth or slightly sulcated concentrically ; sometimes entirely
covered with radiating striz, sometimes the central portions smooth with the lateral
extremities striated; anterior side very short; umbo subterminal; hinge margin
linear, generally smooth, occasionally crenulated or denticulated; ligament internal ;
impressions of the adductor muscles different in form and unequal in size; anterior
one small and elongato-ovate ; posterior one large and subcircular; impression of
the mantle entire ; shell slightly gaping for the passage of a byssus.

Animal of the form of the shell, and the margins of the mantle without a fringe :
an elongated and cylindrical foot, with a gland at its base for the formation of a
byssus.

This genus has by some conchologists been united with the preceding one, in con-
quence of some similarities between the animals’ as well as the shells. In this the
animal differs in having a simple margin to its mantle, as well as a marked peculiarity
in the branchial region, these characters are as distinct as are generally employed for
the separation of genera, and in the shells the anterior side is always more or less
pushed beyond the umbo, so as to give it a Jess triangular or a more trapezoidal form
than in Mytilus. The aberrant species will, it is true, bear a close generic resemblance,
and the line of demarcation is difficult to define, but the same may be said of most
proximate genera. Some modern conchologists have constituted a new genus for those
species which are externally ornamented or striated, a character here considered
insufficient for generic distinction, more especially as in well-determined species of the
preceding genus the shell is sometimes smooth, while in others it is covered with deep
and strongly marked lines of radiating strie.

It is doubtful also whether a line of crenulations upon the dorsal edge of the shell
is a character sufficient alone for generic distinction. The genera Crenella and
Modiolarca have therefore been included in the synonyma. Animals of this genus
generally spin a byssus, by which they are attached, and the shell gapes a little at
the anterior part of the ventral margin for its passage; several species in the recent
state supply this material so largely, as to wholly invest the shell in a kind of nest;
while others closely resembling this genus are capable of forming a habitation in the -
interior of calcareous rocks. (AZytilus lithophagus, Linn.)

This is truly a Marine genus, and found at various depths, and is known among
the oldest of the Secondary Rocks ; but it is rather sparingly distributed throughout
the Tertiaries.

BIVALVIA. 57

1. Mopioxa Mopio.us, Linneus. Tab. VIII, fig. 1, a—d.
Myritus moprotus. Linn. Syst. Nat., ed. 12, No. 256, p. 1158, 1767.
— —_ Da Costa. Brit. Conch., p. 219, t. 15, fig. 5, 1778, (right-hand fig.)
— — Chem. Conch. Cab., vol. viii, p. 178.
— — Donov. Brit. Shells, vol. i, pl. 23, 1799.
a — W. Wood. Ind. Test., p. 53, pl. 12, fig. 31, 1825.
ae — Mill. Zool. Danica, pl. 53.
~ — Flem. Edin. Ency., vol. vii, pl. 203, fig. 22.
— curtus. Penn. Brit. Zool., p. 112, pl. 64, fig. 76, a.
— cuRVIROsTRATUS. Da Costa. Brit. Conch., p. 220, 1778.
— UMBILIcATUS. Penn. Brit. Zool., ed. iv, vol. iv, p. 112, pl. 65, fig. 76.
_ _ Mont. Test. Brit., p. 164, 1803.
— — W. Wood. Ind. Test., pl. 12, fig. 49, 1829.
— BARBATUS. Don. Brit. Shells, vol. ui, pl. 70, 1800.
-— papuaNus. Nyst. Coq. Foss. de Belg., p. 271, 1844.
Mopiona paruaNna? Desh. 2d ed. Lam., t. vii, p. 18.
— — Brown. Brit. Conch. Mlust., pl. 29, figs. 1—4, 1827.
— — Say. Amer. Conch., pl. 45.
= — Leach. Zool. Miscel., vol. ii, p. 33.
— mopioLus. Turt. Brit. Biv., p. 199, pl. 15, fig. 3, 1822.
— — S. Wood. Catalogue, 1840.
= — Dekay. Nat. Hist. New York Zool., p. 185, pl. 24, fig. 257, 1843.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 182, pl. 44, figs. 1, 2,
1849.
— — Midd. Malac. Ross., loc. cit., p. 537, 1849.
— vuuGARIs. Flem. Brit. An., p. 412, 1828.
aoe —_ Lovén. Ind. Moll. Scand., p. 33, 1846.
— — Alder, Cat. Moll. North. and Durh., p. 81, 1847.
— GRANDIS. Phil, En. Moll. Sic., vol. ti, p. 51, t. 15, fig. 13, 1844.
Ency. Meth., p. 219, fig. 1.

Spec. Char. Testa oblongo-ovata, gibbd, levigatd ; margine dorsalt antico brevissimo ;
postico producto, subrecto ; margine ventrali subsinuato ; extremitate utraque rotundato.
Shell oblong-ovate, tumid, and smooth; anterior dorsal margin very short;
posterior much produced, with hinge-line nearly straight ; ventral margin subsinuated,
and both extremities rounded.
Locahty. Cor. Crag ?
Red Crag, Sutton.
Mam. Crag, Postwick, Bridlington.
Recent, Britain, N. Seas, Boreal, America, Mediterranean ?
A few specimens only of this fine shell have been found by myself in the Red Crag,
where it does not appear to have been abundant, although occasionally fragments have
been met with at distant localities, testifying its somewhat general distribution in that
deposit ; a few fragments also of a MJodiolu of a similar form are in my cabinet from
the Coralline Crag at Ramsholt, but the hinge-line being imperfect, I am unable to
8

58 MOLLUSCA FROM THE CRAG.

determine its specific character, and it was introduced into my Catalogue as belonging
with doubt to this species.

In the recent state this shell is thick and strong, but my specimens differ
materially in that character, and are particularly fragile. This species exhibits a
very considerable degree of variation in its outward form or proportional dimen-
sions, as may be observed in the specimens figured, but a similar variability is
shown in the living shell: the two forms may be considered as belonging to one
species, and there can be little doubt of its identity with the shell now common in our
own seas. My specimens were all found at one locality in association with a bed of
Myt. edulis. British Conchologists give it vertical range from low water mark to
sixty fathoms.

I have introduced as a synonym J. grandis Phil., believing it not to differ
specifically from the British shell: some fossil specimens from Sicily (for which I am
much indebted to Madame Power) in my cabinet, presumed to be the same as
Philippi’s species, have no character whereby they can be justly separated from the
shell found upon the coast of Massachusetts. The size of the Mediterranean fossil is
not sufficient for specific distinction, as a specimen of modiolus, measuring seven
inches, is recorded by Captain Brown to have been obtained by a fisherman near the
Bell Rock, on the coast of Forfarshire. ;

2. Moproxta Barsata, Linneus. Tab. VIII, fig. 2.
Myritus Barpatus. Linn. Syst. Nat., ed. 12, p. 1156, sec. Ford. and Hanl.
— — Poli. Test. Sicil., vol. ii, p. 210, pl. 32, figs. 6, 7, 1795.
Mopiota BaRBATA. Lam. Hist. des An. Sans. Vert., t. vi, p. 114, 1818.
— —_ Phil. En. Moll. Sic., vol. i, p. 70, and vol. ii, p. 50.
~— — Forbes. Report. igean Invert., p. 180, 1843.
-- Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 190, pl. 44, fig. 4.
— GispsiI. Leach. Zool. Misc., vol. ii, p. 34, pl. 72, fig. 2, 1815.
— _ Turt. Brit. Biv., p. 200, 1822.
— — Brown. Brit. Conch. Ilust., pl. 29, fig. 7, 1827.
Ency. Meth., pl. 218, fig. 6.

Spec. Char. Testa tenui, ovato-oblongd, extremitate compressiusculd, anticé brevissima,
postice dilatatd, subangulatd ; lineis incrementibus ornata.

Shell thin, of an oblong-ovate form, posterior portion somewhat compressed, dilated
and sub-angulated, anterior extremity very short, concentrically striated, or lines of
increase distinct and prominent.

Locality. Red Crag, Walton Naze. Recent, British and Mediterranean Seas.

About half a dozen specimens from the Red Crag, at Walton on the Naze, appear
precisely in form to resemble what the authors of the ‘ Hist. of Brit. Mollusca,’ seem
to consider as entitled to specific distinction, and presuming they have good data for
their determination, I have separated this from where it had been previously placed,

BIVALVIA. 59

as only a variety of 17. modiolus. A greater curvature in the ventral margin, and the
expansion on the posterior side, are deviations from the ordinary form of the larger
and more common species, and these are, [ presume, the principal characters relied
upon for separation. On the exterior are a series of ridges or elevated lines of
growth, the probable remains of *he support of the bearded or. fringed portion of the
epidermis when in a recent state. The beaks in this specimen appear to be terminal,
the anterior side of the shell not projecting beyond them, and in that character
more resembling Mytilus, which it closely approaches in form; there is, nevertheless,
a projection outwards, like the rest of the genus. The ventral margin is somewhat
incurved, the dorsal portion of the shell a good deal flattened behind, and extending
beyond the ligamental area, while the centre is tumid or inflated; the dimensions
of the widest part, which is on the posterior side behind the ligament, is twice that of
what it measures across the shell immediately behind the umbo.

3. MODIOLA PHASEOLINA, Philippi. Tab. VIII, fig. 4.
MopioLa PHASEOLINA. Phil. En. Moll. Sic., vol. u. p. 51, t. 15, fig. 14, 1844.
—= == Jeffreys. An. Nat. Hist., vol. xix, p. 313.
_ — Forb. and Hanl. Hist. Brit. Moll., vol. ui, p. 186, pl. 44, fig. 3,
1849.

Spec. Char. Testa oblongo-ovatda, levigatd, tenm, margine ventral recto ; subsinuato,
dorsali subangulato, cardine crenulato.

Shell oblong-ovate, smooth and thin; ventral margin straight or subsinuated,
dorsal margin subangulated ; cardinal area crenulated : shell nacreous.

Locality. Coralline Crag, Sutton, and Ramsholt.

Recent, Britain, and Mediterranean.

The distinguishing character of this species appears to be the finely crenulated margin
of the dorsal edge on the outside of the ligamental area, as the outer form or contour of
the shell is variable like J/. modiolus, from the young of which it could not be separated
by any character which might not also be applied to that species ; some specimens have
but a short hinge line, with a somewhat rounded dorsal edge, and a subcylindrical or
ovato-oblong outline, while in others there is a considerable angle on the dorsal edge
at the posterior termination of the ligament, and the ventral margin is nearly straight,
varying sometimes from that line a little, both outwardly and inwardly. The largest
specimens which have a minutely crenulated hinge line do not exceed $ths of an inch,
and all show a pearly texture. The umbo is generally terminal, although the anterior
side will occasionally be seen to project beyond it.

This, as well as the preceding species, have been introduced in deference to the
Malacologists, but it is very doubtful if they will not hereafter have both to be united
with JZ. modiolus.

60 MOLLUSCA FROM THE CRAG.

4. Mopioua cosTutaATa, Risso. Tab. VIII, fig. 6.
Mopioutvs costutatus. Risso. Hist. Nat. de ? Europ. Merid., t. iv, p. 324, pl. xi, fig. 165,
1826, non bene.
Mopriota costutata. Phil. En. Moll. Sic., vol. i, p. 70, t. 5, fig. 11, 1836.
we wa Id, *-) =~ wolsiy p. 50; t. 15, fig, 10) 1e4a,
— Petracnm. (Scacchi) sec. Phil. En. Moll. Sic., vol. ii, p. 51.
— cosTtuLATA. Webb and Bertholet. Nat. Hist. des Hes Canaries, p. 103, pl. 7, B,
figs. 23, 25, 1842.
— — Jeffreys. An. Nat. Hist., vol. xix, p. 313.
— cyLinpDRoIpES. S. Wood. Catalogue, 1540.
CRENELLA COsTULATA. Ford. and Hani. Hist. Brit. Moll., vol. 1, p. 205, pl. 45, fig. 1, 1849.

Spec. Char. Testé minutd, oblongd, subcylindricd, anticé angustata et ultra apicem
productd, medio levi ; in utroque latere costato-striata.

Shell small, oblong, subcylindrical, anterior side somewhat contracted, extending
beyond the umbo, middle smooth, with large costated striae upon both sides.

Longest diameter, 3ths of an inch. Shortest, ths.

Locality. Cor. Crag, Sutton.

Red Crag, Walton Naze.

Only one specimen in my cabinet has been obtained from the older or Coralline
Crag Formation; but in the Red Crag at Walton it does not appeawto be at all scarce,
at least a couple of dozen have fallen to my lot, and in them a considerable range in
variation may be detected.

Our shell appears to agree with the figure and description of J/. costulata, in the
first vol. of Philippi, which that author, in his second volume, has assigned to another
species: amongst my specimens also are forms corresponding with what he con-
siders to be specifically distinct, and they are therefore both introduced among the
synonyma, as I am unable to separate into two species those which are found in the
Crag; if, however, there be in the recent shells characters sufficient to justify a
specific distinction, both forms seem to have been present in the seas that deposited
the Red Crag, but from what is exhibited in the fossils, they may be fairly included in
one species.

There can be no mistake in regarding this as distinct from either J/. discrepans
or M. marmorata, from both of which it differs in being more cylindrical, with
also a greater curvature in the ventral margin. It is an elegantly-formed shell,
the anterior side slightly projects beyond the umbo, somewhat tumid, with a rounded
angularity crossing the shell diagonally from the beaks to the posterior part of the
ventral margin, the anterior side is rounded, and deeply striated or ridged with about
ten or twelve small ribs; the middle is plain, or only marked by lines of growth,
while the greater half of the shell on the posterior side is covered with striz in a
radiating manner, these are so conspicuous at the margin as to produce somewhat
large and distinct crenulations on the inner edge, most conspicuous a little behind the

BIVALVIA. 61

ligament, but they extend along the whole line of hinge or dorsal area; the posterior
side in some specimens is much rounded, so as to give a cylindrical form to the shell,
while in others there is an angular slope on the posterior side, from a little beyond
the termination of the hinge line to the ventral margin, which gives a greater width
to that part, thereby producing a different form, and which, in consequence, were that
a permanent character, might be considered a distinct species, but my specimens are
exceedingly variable, so as to present no marked distinction between the two.

5. MopioLa SERICEA, Broun. Tab. VIII, fig. 3.
MopioLa sERIcEA. Bronn. Ital. Tert. Geb., p. 122, No. 649, 1831.
— — Phil. En. Moll. Sic., vol. i, p. 71, t. 5, fig. 14, 1836.
— Ta = - vol. ii, p. 52, 1844.
_ — Nyst. Add. a la Faune. Conch., p. 444, No. 38, 1842.
— HYALINA. iS. Wood. Catalogue, 1840.
MytiLus sERICEUS. Goldf. Pet., vol. ii, p. 179, pl. 131, fig. 12, a—e, 1841.
— — Nyst. Conch. Foss. de Belg., p. 271, pl. 21, fig. 2, B—e, 1844.
— _ E. Sism. Synop. Meth. An. Invert., p. 15, 1847.
Bronn. Ergeb. meiner. naturh.-dkon Reise, vol. ii, p. 620, sec. Nyst.

Spec. Char. Testa tenuissime, subhyalind, elliptico-ovatd, tumidd ; valde inequilatera ;
striata, striolis eailibus confertis ; umbonibus prominentibus recurvis ; margine ventrali
subrecto, tenuissime crenulato.

Shell thin delicate, subhyaline, of an elliptical or ovate form, tumid; very inequi-
lateral ; covered externally with numerous close-set, extremely fine, radiating striz ;
umbo projecting beyond the anterior side; ventral margin nearly straight and
finely crenulated.

Locality. Cor. Crag, Ramsholt and Sutton.

It is very difficult to obtain specimens of this species in perfection, on account of
its extreme thinness, although they appeared at Ramsholt to be by no means rare, but
they are generally more or less broken or distorted.

This beautiful species is of an ovate or elliptical form, very tumid, excessively
thin and semitransparent ; it is covered over its whole surface with extremely
fine radiating striz, crossed occasionally by irregular lines of growth, but not
regularly decussated; the ligamental area extends about half the distance of the
dorsal portion, its termination forming a very obtuse angle ; the umbo is terminal and
somewhat prominent, curved, and slightly projecting beyond the anterior margin.

This appears at present to be known only as a fossil. My largest specimen
measures an inch and a quarter in its longest diameter.

62 MOLLUSCA FROM THE CRAG.

6. Moprota MARMORATA, Forbes. Tab. VIII, fig. 7.
Mytinus piscors. Da Costa. Brit. Conch., p. 221, t. 17, fig. 1, 1778.
A= =S Walker and Boys. Test. Min. Rar., pl. 3, fig. 79, 1789.
— — Poli. Test. Utr. Sic., vol. ii, p. 211, pl. 32, figs. 15, 16, 1795.
— — Donov. Brit. Shells, vol. i, pl. 25, fig. 1, 1799.
— Mat. and Rock. Linn. Trans., vol. viii, p. 111, pl. 3, fig. 8, 1807.
— — Mawe. Conch., pl. 13, fig. 5, 1823.
— W. Wood. Ind. Test., pl. 12, fig. 39, 1825.
Mopiota — Turt. Brit. Biv., p. 201, pl. 15, fig. 4, 1822.
— — Brown. Ilust. Brit. Conch., pl. 29, fig. 10, 1827.
_ — S. Wood. Catalogue, 1840.
— — % Gould. Inv. Massach., p. 15, fig. 84, 1841.
— DISCREPANS. Phil, En. Moll. Sic., vol. i, p. 70, 1836.
— — Id, - - - vol. ii, p. 50, pl. 15, fig. 11, 1844.
— — Payr. Cat. Moll. Cors., p. 67, 1826.
— Evuropma. D’Orb. fide Lovén.
— Tumina. Hanley. Rec. Shells, vol. i, p. 241, pl. 12, fig. 39.
— MARMORATA. Forbes. Malac. Monen., p. 44, 1838.
= — Brown. Mlust. Brit. Conch., 2d ed., pl. 27, fig. 10.
— — Alder. Cat. Moll. North. and Durh., p. 82, 1848.
Moptotaria — Lovén. Ind. Moll. Scand., p. 33, 1846.
CRENELLA — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 198, pl. 45, fig. 4, 1849.

Spec. Char. Testé minutd, ovato-ellipticd, tumidd, tenui, fragili; utroque latere
striata, spatio submediano levigato vel transverse striato; umbonibus minimis subter-
minalibus.

Shell small, ovate or elliptical, tumid, thin, and fragile; both sides radiatingly
striated, with a smooth or rather transversely striated space between them ; umbones
small, subterminal.

Longest diameter, 3ths of an inch.

Locality. Cor. Crag, Sutton.

Red Crag, Walton Naze.
Recent, Mediterranean, Britain, Scandinavia, and North America?

Small specimens and fragments of this species are abundant in the Coralline
Crag at Sutton, and it appears to have been one of the commoner shells of that
Period. There is no doubt, of this shell being identical with the recent British
species, now determined not to be the discors of Linnzus, a name given to a larger
shell (Mytulus impactus, Herm.) by the Swedish naturalist.

Our shell in the fossil state has become opaque, but it has retained its nacreous
appearance ; it is of an elliptical form, the anterior side being rather broader than the
posterior, which is slightly narrowed off from the dorsal slope ; the umbones are small,
slightly inflected, with the anterior side projecting a little beyond them, the shell is
somewhat regularly tumid, with a very slight flattening on the dorsal portion: the

BIVALVIA. 63

tripartite division of the exterior is of unequal dimensions, the posterior strize covering
nearly but not quite half the surface, while the anterior occupies rather a less space than
the centre or naked compartment ; the striz or rays are large and rounded, number-
ing about a dozen or fourteen on the anterior side, with about double that number on
the posterior portion: the whole shell is covered with transverse striz or regular
lines of increase, which prettily ornament the spaces between the ridges, and
the edge of the shell is deeply crenulated on the anterior and posterior sides, or
those portions which are covered with the radiating ridges; the tripartite division
of the shell, is visible in the interior, and the number of the external strize may be
counted there. The edge of the ventral margin has a slight convexity, contracting a
little towards the striated parts.

The differences between this species and the following are so evident, there
can be no mistake, that shell being more compressed or less tumid, with the posterior
side broader in proportion. The shell to which this approaches nearest, is
M. semi-nuda, Desh., ‘Desc. des Coq. Foss. des Env. de Par.,’ vol. i, p. 264, pl. 30,
figs. 20—22, a fossil belonging to the Formations of the Older Tertiaries. I have not
been able to obtain a specimen from the Paris Basin; but what I presume to be the
same species in the Cabinet of Mr. Edwards, from the English Deposits, presents
differences that may be regarded as specific. Mr. Edwards’s shell is more regularly
ovate, and is even thinner than our species, with fewer radiations on the anterior
side, not having more than seven or eight, and these are broader, it is also, more
regularly tumid than our own shell, which has somewhat of an obtuse angle on the
posterior portion.

The shell figured and described by Dr. Gould, under the name of JZ. discors, seems
to present but trifling differences with the British shell, judging from description alone ;
but it is considered to be distinct by British Conchologists, as well as by Dr. Lovén.

7. Mopioua piscors, Linneus. Tab. VIII, fig. 5.
MytILus piscors. Linn. Syst. Nat., ed. 12, p. 1159, No. 261, 1767.
— piscrepans. Mont. Test. Brit., p. 169, 1803.
Mopiozra piscrepans. Turt. Brit. Biv., p. 202, 1822.
— — Desh. 2d ed. Lam., t. vii, p. 23, 1835.
oo — Forbes. Malac. Monens., p. 44, 1838.
— a Miller. Ind. Moll. Groenl., p. 19, 1842.
— — Alder, Cat. Moll. North. and Durh., p. 81, 1848.
Mopronarta piscors. Lovén. Ind Moll. Scand., p. 33, 1846.
CRENELLA oiscors. Forb, and Hanl. Hist. Brit. Moll., vol. ii, p. 195, pl. 45, figs. 5, 6,
and pl. 48, fig. 5, 1849.

Spec. Char. Testa ovato-ellipticd, subcompressd, valdé inequilaterd, tenui ; anticé et
posticé striata, spatio mediano levigato ; latere postico latiore.
Shell ovato-elliptical, somewhat compressed, very inequilateral, thin; striated at

64 MOLLUSCA FROM THE CRAG.

both extremities, middle space smooth, posterior side of the shell broader than the
anterior.

Longest Diameter, 4 an inch.

Locality. Mam. Crag, Chillesford. Recent, Britain and Seas of Norway.

A specimen strongly resembling this species is in my Cabinet, obtained in the
native bed of the Mammaliferous or Newer Crag Period, at Chillesford. The shells
in that deposit are excessively fragile, and are preserved with difficulty. This
specimen appears also to have lost a portion of its outer surface: there is, however,
upon the exterior, traces of what the sculpture has been, and as far as it can be observed,
it seems to correspond with that upon the recent shell, it is, therefore, appropriated to
the above species without much doubt; and, as its congeners in the same deposit are
such as we know to be its associates at the present day, it might fairly be expected
in that Formation. In the recent state it is considered more of a Boreal form, with
but a limited range to the Southward. The earliest appearance of this species is
in the upper portion of the Crag, where it seems to have been by no means
abundant. I have found it in the recent state upon the shore of the Coast of Suffolk,
in pools of water, left by the retreat of the tide.

8. MopioLa RHOMBEA, Serkeley. Tab. VIII, fig. 8.

Moprota Pripeauxtana. Leach. Zool. Miscel., vol. ii, p. 35, 1815.
— — Brown. Brit. Conch. Illust., pl. 29, fig. 9, 1827.
— RHOMBEA. Berkeley. Zool. Journ., vol. iii, p. 229, Suppl. pl. 18, fig. 1, 1827.
— — Thorpe. Brit. Mar. Conch., p. 107, 1844.
ao — Brown. Brit. Conch. Illust., 2d ed., p. 78, pl. 39, fig. 17.
—_ ASPERULA. S. Wood. Catalogue, 1840.

CRENELLA RHOMBEA. Ford. and Hanl. Uist. Brit. Shells., vol. ii, p. 208, pl. 45, fig. 3,

1849.

Spec. Char. Testa minutd ovato-oblongd vel trapeziformi, tumidd, inflatd, crassé ;
costulato-striatd, sulcis vel struis divaricatis ; antice abbreviatd, rotundatdé, posticé majiore,
angulata ; margine ventral sinuato ; natibus prominulis incurvis.

Shell small ovato-oblong or trapeziform, tumid, or inflated, covered all over with
large or costulated bifurcating strie ; anterior side, short and rounded, posterior
larger, and angulated; ventral margin sinuated, with incurved and slightly projecting ©
umbones.

Greatest Diameter, 4th of an inch.

Locality. Cor. Crag, Sutton. Recent, British Seas, and Coast of Sutherland.

This is considered by the authors of the ‘ Hist. of Brit. Mollusca,’ as an extremely
rare shell in the recent state, and somewhat of a modern addition to the Wurine
Fauna, of the British Isles. Although noticed by Dr. Leach as early as the year
1815, it has since rarely been met with and seldom seen in the Cabinets of collectors.
It is not so in the fossil, but is very abundant in the rich depdt of small shells at Sutton.

BIVALVIA. 65

The recent shell is said to be as much as a quarter of an inch in diameter:
the largest of my fossil specimens, does not exceed the sixth of an inch in its
extreme dimensions, measured diagonally from the umbo to the posterior part of its
ventral margin. There is, nevertheless, but little doubt of their identity, as the
only difference is that of size, the Crag specimens corresponding in all other charac-
ters with the recent shell. It is very much inflated: the two valves when united,
having a greater diameter than is given when measuring from the dorsal to the
ventral margin ; the umbo is terminal, projecting a little beyond the anterior of the
shell, and is slightly curved; it is somewhat rhomboidal in its contour, with a little
obliquity towards the posterior side, and a slight indentation in the ventral margin,
the posterior side forming an obtuse angle with the edge of the shell that contains the
ligament; the exterior is ornamented with large prominent striz, or rather small ribs
which bifurcate, and are more numerous in the old than in the young shell, they
are crossed and made somewhat rough by prominent and distinct lines of growth,
at rather irregular distances, sometimes giving a decussated appearance to the shell ;
the prominent costulated strize project beyond the margin, and give a deeply
crenulated edge all round; the ribs are sometimes visible in the interior, although
the specimens are often so thick as not to allow them to be seen on the inside ; and
in that case, the impressions formed by the muscles are deeply indented, that by the
anterior adductor is comparatively very large. The ligament seems to have been
a strong one, as a deep linear depression is formed within the dorsal margin. This
shell has been dredged in the living state, in 20 fathoms water, off Penzance.

PECTUNCULUS,* Lamarck, 1791.

PrectuncuLus PoLyLeproGincLyMus (sp.) List., 1687.
Mactra? Browne, 1756.

Arca (spec.). Linn., 1767.

GuiycimERtIs. Da Costa, 1778. Humph., 1797.
AXxIN@/A AXINHODERMA. Poli, 1795.

Tucreta. Bolton, 1798, sec. Herrm.

Generic Character. Equivalve, orbicular, convex or lenticular, subequilateral,
closed, thick and strong; externally smooth or ornamented with radiating striz or
coste. Hinge teeth small, numerous, forming an arched or curved line, central
denticles becoming obsolete in old shells. Ligament external, attached to a grooved
area in each valve, with distant beaks. Impressions of the adductors two, lateral
and strongly marked, that by the mantle entire, or without a sinus.

* Etym. The diminutive of Pecten.

56 MOLLUSCA FROM THE CRAG.

Animal orbicular, or of the form of the shell and capable of being entirely covered
when the valves are closed, mantle with its margins simple and disconnected, some-
what enlarged in the anal regions; a large semilunar shaped foot with undulating
edges, permitting an expansion into a subdiscoidal form. No byssus..

This is purely a marine genus, inhabiting waters of various depths, with an
extensive geographical range ; though it does not as yet appear to have been found in
any of the very cold regions of the globe. In a recent state the shells are generally
covered with a velvety epidermis, except about the umbones, where it is often
worn off.

The species are not numerous, either recent or in a fossil state, but appear to
have long been inhabitants of this planet, two or three are described by Colonel
Portlock, from the Silurian Rocks of Tyrone, and others have been found in the
Oolites and Green sand, but the shells are not of. any magnitude, until the Tertiary
Periods, in which as individuals they are largely developed, both in Europe and in the
Upper Tertiaries of America.

This is a well-marked genus, and not likely to be confounded with any other,
except Limopsis, from which, however, it may be distinguished by the ligamental
area being simple, or only marked with angular or diverging lines, while in that shell
the cartilage is more distinctly separated from the ligament, and placed in a triangular
fossette immediately beneath the beaks.

The ligament in this genus occupies the entire space between the umbo and the
hinge margin, not equally spread over the surface, but placed in diagonal, or rather in
lines diverging from the beak towards the lateral margins, by which a deep impress or
furrow is formed and left upon that part of the shell.

], PECTUNCULUS GLYCIMERIS, Linnaeus. Tab. IX, fig. 1, a—h.
Bonanni. Recr. Ment. et Ocul., fig. 61, 1684.
CHaMA GLYCIMERIS Bettoni. List. Hist. Conch., lib. iii, pars 11, fig. 82, and fig. 80?
1687.
PrctuNncuLus FossILis. Dale. Hist. and Antiq. of Harw., p. 291, t. xi, fig. 3, 1730.
ARCA GLYCIMERIS. Linn. Syst. Nat., ed. 12, p. 1143, No. 181, 1767.
_- —- Poli. Test. Sicil., vol. ii, p. 144, t. 26, fig. 1; t. 25, fig. 19, 1795.
— — Don. Brit. Shells, vol. ii, pl. 37, fig. 2, 1800.
— — Mat. and Rack. Linn. Trans., vol. viii, p. 94, t. 3, fig. 3, 1807.
— — W. Wood. Ind. Test., p. 46, pl. 10, fig. 36, 1825.
-— — Mawe. Lin. Syst. Conch., pl. 13, fig. 7, 1823.
a a Burrow. Elem. of Conch., p. 143, pl. 8, fig. 7.
— pitosa. Linn. Syst. Nat., ed. 12, No. 182, p. 1143, 1767.
— — Poli. Test. Sicil., vol. ii, p. 138, t. 26, fig. 2—4, 1795.
— — Broc. Conch. Foss. Subap., p. 487, 1814.
— — Mat. and Rack. Linn. Trans., vol. viii, p. 94, t. 3, fig. 4, 1807.
— — W. Wood. Ind. Test., p. 46, pl. 10, fig. 37, 1825.
Arca scripra. Born. Mus. Cees. Vin., p. 93, t. vi, fig. 1, 1780.
— unpAta. Chem. Conch. Cab., vol. vii, p. 224, pl. 57, fig. 560, 1784.

BIVALVIA. 67

Arca unDATA. Broc. Conch. Foss. Subap., p. 489, 1814.
— POLYODONTA. Broc,- - - p- 490, 1814.
— FLAMMULATA. Renieri. fide Philippi.
GLYCIMERIS ORBICULARIS. Da Costa. Brit. Conch., p. 168, p. 11, fig. 2, 1778.
PECTUNCULUS GLYCIMERIS. Turt. Brit. Biv., p. 171, t. 12, fig. 1, 1822.
— — Brown. Illust. Conch. Gr. Brit., pl. 25, figs. 8, 9, 1827.
—_ — Crouch. Int. Lam. Conch., pl. 8, fig. 11, 1827.
— — Reeve. Conch. Icon. Pectune., pl. 3, fig. 12.
a _— Dward. Mem. Geol. Soc. de Fr., ts ii, par. 11, p. 267, No. 1,
1837.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 245, pl. 46,
figs. 4—7, 1849.
— PiItosus. Turt. Brit. Biv., p. 172, t. 12, fig. 2; 1822.
— _ Schum. Essai d’un Nouv. Syst. des Vers. Test., p. 172, pl. 19,
fig. 3, 1817.
— — Brown. Mlust. Conch. G. B., pl. 25, figs. 10, 11, 1827.
— — Blainv. Man. Malac., pl. 65 bis, fig. 3, 1825.
— — Reeve. Conch. Icon. Pectune., pl. 3, fig. 13.
— — G. Sowerby, Jr. Conch. Man., fig. 134, 1843,
— — G. Sow. Genera, No. 5, fig. 1.
— — S. Wood. Mag. Nat. Hist., 1840, p. 13, fig. 7.
— — Nyst. Coq. Foss. de Belg., p. 247, pl. 19, figs. 6, 7, 1844.
— unpatus. Turt. Brit. Biv., p. 173, t. 12, figs. 3, 4, 1822.
— pEcussatus. Id. - p. 173, t. 12, fig. 5.
— NuMARIvus. Turt. Brit. Biv., p. 174, t. 12, fig. 6, 1822.
— VARIABILIS. J. Sow. Min. Conch., t. 471, fig. 1, 1824.
— — Woodward. Geol. of Norf., p. 43, 1833.
_ _ Id. Coq. Foss. de Belg., p. 249, pl. 20, fig. 1, a—b, 1844.
— — Phil. En. Moll. Sic., vol. ii, p. 45, 1844.
— PoLyoponTa. Goldf. Pet. Germ., vol. li, p. 161, t. 126, gs. 6 & 7, a—d.
— PULVINATUS. Brongn. Vincent., p. 77, pl. 6, figs. 15, 16, 1823.
— — ? Bast. Bord. Foss., p. 77, No. 2, 1825.
—_ — ? Dubois de Mont. Conch. Foss. de Wolhyn., p. 64, pl. 7,
figs. 7, 8, 1831.
— suBOBLIQUUS. S. Wood. Mag. Nat. Hist., 1840, p. 233, pl. 13, fig. 6.
— TRANSVERSUS.? Dubois de Mont. Coq. Foss. de Wolhyn., p. 65, pl. 7. fig. 9.
— NUMIFORMIs. ? Id. - - + - p- 66, pl. 7, fig. 6.
— LATIAREA. Michelotti. fide Sismonda.
_ PusILLus? Dward. Mem. Geol. Soe. de Fr., t. 2, pt. 2, p. 276, 1837.
Ency. Method., p. 310, figs. 2 & 3.
Arca. Smith. Strat. Identif. Craig, t. 2, fig. 7, 1816.

Spec. Char. Testé variabile, suborbiculatd, subovatd, transversd, sepée obliqud sub-
aquilaterd, compressa vel tumidda, costato-striatd ; margine crenulato.

Shell variable, suborbicular, elongate or transverse, often oblique, subequilateral,
compressed or tumid ; striated ; margin crenulated.

Diameter, 34 inches.

68 MOLLUSCA FROM THE CRAG.

Locality. Cor. Crag, Passim.
Red Crag, Passim.—Var. 3, swbobliquus, Walton Naze.
Mam. Crag, Thorpe, Bridlington (Leckenby).
Recent, Britain, and Mediterranean.
This is one of the most common and abundant shells in the Coralline as well
as in the Red Crag Deposits. In the Coralline, the valves, as might be expected, are
often found united.

The determination of this species is exceedingly difficult, and the form which was
figured in the ‘Mag. Nat. Hist.’ (var. 8), presented characters it was then thought
sufficient for the establishment of a new one, but the recent species has been found to
exhibit the same obliquity ; this variety I have never seen from the Older or Coralline
Crag, but it is one of the commonest shells at Walton on the Naze, where the two
valves are frequently found united; it is generally thinner, and some specimens
are very oblique, and this may be considered the limit of range in variation in
one direction ; var. a in the other; between these forms every imaginable gradation
may be pointed out in almost any collection possessing a good series of this abundant
Crag shell, so well named by Mr. J. Sowerby (variabiliis). There is scarcely a
possibility of giving a correct diagnosis of this species, but what some deviation may
be pointed out, and in consequence of which the varieties have been made into
several species, as may be seen in the above list of synonyma, all, it is presumed,
belong to this species. Specimens are somtimes longer than they are broad, and vice
versd, some are lenticular, with but little tumidity, others are much inflated. The
exterior is generally more or less ornamented with raised, radiating, and distant strie,
variable in number, producing a like variation in the number of crenulations upon the
interior margin of the valves ; in some they are as many as sixty, while in others they
do not exceed thirty-five; neither is the number of teeth or denticles of the hinge a
more permanent character, for in old specimens the ligamental area is pushed so
far forward as to have obliterated all the central teeth, and they become almost
toothless, not more than three or four remaining; while in some specimens as many as
eighteen may be counted on each side of the umbo, they are prominent, somewhat
angular, flattened on the top, and when perfect, generally crenulated on the edges;
between each is a deep depression for the reception of those in the opposing valve,
and in very young shells the hinge is almost entirely destitute of denticles (fig. 1, e).
Every size may be readily obtained, and my cabinet contains a series varying from
specimens less than the eighth of an inch to those in which the diameter is nearly
three and a half inches, dimensions exceeding those generally obtaimed in our seas ;
and this magnitude may be seen in shells from the Coralline as well as the Red Crag
Deposits, while the species seems to have been rare in the Norwich beds.

Some American Tertiary shells figured by Conrad under two or three different

names, approach so closely to those of the Crag as to render the distinction doubéful;
as far as regards representation alone.

BIVALVIA. 69

In some of my specimens from the Coralline Crag, where the two valves are in
their natural state a very perceptible difference may be observed, not only in one
valve having a greater tumidity than the other, but the inflated valve has also a larger
diameter. Perhaps the ovarium in these specimens occupied a position not quite
central, thereby giving a little inequality to the valves.

There are nodules of indurated sandstone in my cabinet, which contain casts of
what appear to be the interior of this species, and also those of Jsocardia cor. where the
shell has been absorbed or abstracted ; these nodules were obtained on‘the beaches of
Walton Naze and Felixstow, and were in all probability washed out of the Red Crag.

Limopsis, Sassi. 1827.

Arca (spec). Brocchi.

Triconocatius. Nyst et Galeotti, 1835.
Limnopsis. Gray, 1840.
Precruncutina. D’Orb, 1844.
CRENELLA. Herrmansen, 1846.

Generic Character. Shell orbicular or obliquely ovate, convex or lenticular, equi-
valved, subequilateral, and closed. Hinge composed of numerous teeth, arranged in
amore or less curvilinear direction, projecting and interlocking. Umbones distant.
Cardinal area large and external, divided by a triangular fossette immediately beneath
the umbo. Impression of the mantle entire, or without a sinus; those by the adductors
subovate, and deeply impressed.

ANIMAL UNKNOWN.

The characters by which this Genus is distinguished from the preceding one is
the triangular fossette in the centre of the ligamental area, separating the cartilage
from the ligament; first proposed as of generic importance by Sassi, in 1827,
according to Bronn, and his name has priority over that by MM. Nyst and Galeotti,
which bears a date several years later. This peculiar character of the hinge
was observed and pointed out by Brocchi in 1814, but of course considered by him
as of specific value only, his shell being placed in the genus 4vca. The separation
‘of the ligament into two distinct portions, although both of these are placed exterior
to the hinge line, appears equivalent to the otherwise more general distinction of this
ligature, one portion being within the hinge line, while the other is on the outside.
Highteen species are enumerated by M. Nyst, one of which is recent from the
Red Sea.

70 MOLLUSCA FROM THE CRAG.

1. Limopsis aurita, Brocchi. Tab. IX, fig. 2.
Arca avurtta. Broc. Conch. Foss. Subap., p. 485, t. xi, fig. 9, a—é, 1814.
Pectuncunus auritus. Defr. Dict. Scien., t. xxxix, p. 224.
— — Goldf. Pet. Germ., v. ii, p. 163, t. 126, fig. 14, a—é.
— — Phil. En. Moll. Sic., vol. i, p. 63; vol. ii. p. 45.
= = Risso. Hist. Nat. des Princip. Prod. del’ Europ., t. iv, p. 318, 1826,
— suBLZvIeATUS. S. Wood. Catalogue, 1840.
= — Morris. Cat. Brit. Foss., p. 97, 1843.
Limopsis auriTa. Sassi. Giorn. Ligust. (ex. Bronn), 1827.
— — Bronn. Leth. Geo., vol. 1i, p. 935, t. 39, fig. 7, a—b, 1838.
—— — Sismonda. Syn. Meth. Ped. Foss., p. 15, 1847.
TRIGONOC@LIA SUBLHVIGATA. Nyst. et West. Nouv. Rech. Coq. Foss. d’Anv., p. 12, pl. 2,
fig. 15, 1839.
— — Nyst. Coq. Foss. de Belg., p. 244, pl. 26, fig. 2, a—6, 1844.

Spec. Char. Testé obliqud, rotundato-ovatd, mequilaterd, sublevigatd, auriculaté ;
exilissimé striatd, et tenuissime decussatéd ; cardine arcuata, dentibus 10—18 ; margine
integerrimo, acuto.

Shell oblique, rounded ovate, inequilateral, nearly smooth, and glossy, with small
auricles; externally ornamented with very fine striz, crossed by distinct lines of
growth; hinge line curved, with about 10 to 18 teeth; margin sharp and smooth.

Longest diameter, + an inch.

Locality, Cor. Crag, Gedgrave.

This species has recently been found in abundance in one locality of the Coralline
Crag, but it appears restricted to that spot, it may possibly have lived on into the Red
Crag period, as my cabinet contains one specimen from that Formation, which however
is much waterworn.

It is subject to a good deal of variation in its outward form, but is always
more or less obliquely oval, generally becoming especially so in the older speci-
mens, while in some young shells the valves are nearly equilateral. The hinge is
composed of a row of denticles, varying from ten to sixteen, those on the shorter or
rounded side being the greater number, amounting to about nine, the outermost are
angular and somewhat distant, while the inner ones are close set and vertical; on the
other side they are fewer, not exceeding seven, sometimes not more than four, these
are distant, much inclined, and nearly parallel to the hinge line, furthermore they are
often rough and crenulated upon their edges. The exterior of the shell is smooth and
even glossy when perfect, with faint but distinct radiating strize and visible lines of
growth, and the hinge line projects a little beyond the otherwise oval contour of the
shell, giving it the appearance of auricles, hence its name; the inner margin is
flattened, smooth, and perfectly free from crenulations, and the impressions by the
adductors deeply seated; that on the shorter side small and ovate placed near the

hinge, the other is larger and more distant; the fossette for the cartilage diverges from
the umbo at an angle of about 90°.

BIVALVIA. i

In the young state the specimens have fewer teeth, and the shell, as before stated,
is less oblique, resembling the young of Pectunculus, from which it may be distinguished
by its smooth and acute margin at all ages; while in the very small or young specimens
of P. glycimeris the crenulated edge may be always seen. Some specimens are more
tumid than others, but none are much inflated, and the exterior is smooth and perfect,
except where it has been eroded, when the rays are more displayed, giving it there a
granulated or decussated appearance, like Arca aurita of Brocchi, from which it appears
to differ only in size.

The remains of red-coloured bands may be seen upon some specimens as if the
shell had been so ornamented when in a living state, or perhaps it was of one
uniform colour, a part of which only has been abstracted.

Trigonocelhia Goldfussii, Nyst, from Kleyn Spauwen, much resembles our shell, but
is probably specifically distinct; it has its margin obsoletely crenulated, and the
denticles are more numerous, with a slight difference in their arrangement.

Limopsis pyGM@A, Philippi. Tab. IX, fig. 3.
PEcTUNCULUs PYemMmuUS. Phil. En. Moll. Sic. vol. i, p. 63, t. 5, fig. 5, 1836; not Lamarck.
— = Id. - - - vol. ii, p. 45, 1844.
— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 234, pl. 13,
fig. 5, 1840.
—- — Id. Catalogue, 1840.
— — Goldf. Pet. Germ. vol. ii, p. 162, t. 126, fig. 11, a—e.
_— — Morris. Cat. Brit. Foss., p. 97, 1843.
Triconoc@1ia pEcussaTa. Nyst et West. Nouv. Rech. Coq. Foss. d’Anv., p. 12, No. 29,
pl. 2, fig. 16, 1839.
— — Nyst. Coq. Foss. de Belg., p. 245, pl. 18, fig. 7, a—d, 1844.
Limopsis pyamma. Stsm. Syn. Meth. Ped. Foss., p. 15, 1847.

Spec. Char. Testé minuté, obliqud, inequilaterd, subtrapeziformi, gibbosd, crassd,
auriculaté ; transversim sulcatd, striis radiantibus tenuissimis, subobsoletis ; margine
crenulato, dentibus circa decem.

Shell small, oblique, inequilateral, subtrapeziform, gibbous, thick, and strong;
hinge line straight, furnished with about ten teeth ; externally covered with fine and
nearly obsolete radiating striz, crossed by more distant and distinct lines of increase ;
margin crenulated.

Longest diameter, % of an inch.

Locality. Cor. Crag, Sutton.

This species, as far as I know, is restricted to a single locality, where it is one of
the most abundant shells, and the two valves are often found united. I have little
doubt it is the same as Philippi’s Sicilian fossil, judging from the figure he has given ;
the Belgian shell appears rather larger or badly represented, but from description it is
probably the same. Our shell may be further described as being very tumid, the
depth of the valves united equals the width of the hinge line; its dental formula

72 MOLLUSCA FROM THE CRAG.

consists of about ten teeth, six upon the anterior or rounded side, these are placed
nearly vertical, or forming an obtuse angle, and very prominent in the centre, the four
teeth on the posterior or produced side are much inclined and nearly parallel with the
hinge line, they are also obtusely angular, interlocking between those of the opposite
valve, and by their prominence keeping the two portions united; hinge margin with a
row of crenulations deeper, larger, and more visible within upon the posterior side :
when the shell is perfect the exterior is finely decussated, the radiating striz not
being more prominent than the lines of growth, but when the exterior coating is
removed, which is generally the case more or less, the surface is strongly rayed or
costated. In the young state the shell is less tumid than when full grown and less
oblique. The muscular impressions are unequal in size and suborbicular, the anterior
one or that upon the shorter side is situated close up to the hinge line; the one
on the posterior or opposite side is Jarger and much nearer to the ventral margin.

This shell in form and magnitude bears a resemblance to Pectunculus nanus,
Deshayes, an Eocene fossil from the Paris Basin, figured and described in his ‘ Hist.
des Cog. Foss. des Env. de Paris, vol. i, p. 226, t. 36, figs. 4, 5,6; but judging from the
figure as well as from the description, there appears a different arrangement of the
teeth or denticles, those of the French shell have the greater number upon the larger
or produced side, amounting to as many as six, with only three or four upon the other
or shorter side, and are less oblique, thus reversing the dental arrangement of the Crag
shell; and the French fossil is said to be thin and fragile, while ours is thick and strong.
The triangular fossette of the Crag shell is deep, and forms an angle less than 90°,
and the margin of the shell is perfectly closed all round.

NUCINELLA, S. Wood.

Nucu.a (sp.). Deshayes, 1829.
Pievropon. S. Wood, 1840.
Nucutina. D’Orbigny, 1845, sec. Gray.

Gen. Char. Shell equivalve, inequilateral, closed, ovate or subtrigonal; anterior
side short, truncate; posterior produced, ovate or subangular; hinge line broad
slightly curved, furnished with few teeth: one large lateral tooth on the posterior
side. Ligament external.

ANIMAL UNKNOWN.

The diagnosis of this was drawn up from what may be considered as scarcely
sufficient materials for the distinction of a group of animals, denominated a Genus,
being founded upon but one species; it presents, however, such marked differ-
ences in character from any genus hitherto established, that I was unable to find
a position for my little shell when it was first described. The outward trigonal

BIVALVIA. 73

form, as well as possessing a linear series of denticles, seem to point out its place
as near to WVucula from which it differs essentially, in having an external ligament,
and one large lateral tooth upon the anterior side.

The shell is of a nacreous texture within, and was, probably, covered with an
epidermis in the recent state. The ligament is placed on the posterior side of the
umbo, upon a small projecting portion of the shell, and the animal was without
prolonged siphonal tubes, the line impressed by the edge of the mantle being like
that of Nucula, without any indentation. There are no recent species, that I am
acquainted with, possessing such a dental arrangement, and its true position is of
course conjectural. The linear teeth and external ligament resemble Pectunculus, with
a form like that of Nucwla.

1. NUCINELLA MILIARIS, Deshayes. Tab. X, fig. 4, a—c.
Nucuta miLiariIs. Desh. Coq. Foss. des Env. de Par., tom.i, p. 225, pl. 36, figs. 7-9,
1829.
PLEURODON ovaLts. SS. Wood. Illust. in Mag. Nat. Hist., 2d Series, vol. iv, p. 231, pl. 13,
fig. 1, 1840.
— minaRis. S. Wood. Catalogue, 1840.

Spec. Char. Testé minima, subovatd, levigata, politad, tumidd ; posticé subtruncatd,
anticé productiore, rotundato-ovatd : dentibus 5—6 magnis, obtusis.

Shell minute, subovate, smooth, glossy, and tumid; posterior side short, subtrun-
cate, anterior large, roundedly ovate; teeth 5—6, large and obtuse.

Diameter, =; of an inch.

Locality. Paris Basin, Grignon.

Cor. Crag, Ramsholt, and Sutton.

This pretty little shell is by no means rare at either of the above British localities,
and at the former (Ramsholt), the valves are often found united, the large and pro-
minent teeth with which they are furnished having kept them im their natural position.

‘It is one of the very few of our Crag Molluscs, that dates its existence from the
Older Tertiaries, or what is called the Eocene Period; as there is reason to believe
the species left in the Paris Basin is the true progenitor of our little shell, while it
appears to have died out before the severer conditions of the Red Crag Period had set
in: although so small a shell, it would not readily be found, unless abundant, in a
deposit so disturbed.

As, however, some differences exist between the Crag Fossil, and what is here
considered its specific parent, it may be necessary to give a more detailed description
and to point out what, perhaps, might be regarded by some Conchologists as of
sufficient importance to keep them distinct.

Our little shell in its outward form, slightly resembles a minute specimen of
Nucula nucleus, except, that it is more tumid; the anterior side constitutes nearly
the whole of the shell, the posterior being cut off by an almost straight line from the

10

74 MOLLUSCA FROM THE CRAG.

umbo to the ventral margin. The hinge is composed of five or occasionally six
teeth in the right valve, with six or sometimes seven in the left, these are arranged
in a slightly curved line extending on both sides of the beak, three on each side ;
those on the posterior or shorter side are placed rather closer together than those
on the anterior one, they are prominent, obtuse, and large compared with the
size of the shell; those in the centre standing nearly perpendicular to the line of
hinge, while the outer ones on both sides have their widest portion in an opposite
direction, all placed, of course, so as one set can be interposed between those of
the opposite, when the valves are closed. The lateral tooth of the right valve
has a deep depression between it and the margin for the reception of a large tooth
of the left valve. Ina specimen of the French Eocene Fossil in my own cabinet, the
teeth do not appear to be quite so obtuse as in the Crag shell, and the umbo is somewhat
sharper and more terminal, with a rather more angular outline, the posterior side is
apparently more truncated or straight, while the shell is nearly transparent.

A species passing out of one Period, where the animals or the remains of them, are
of a nature to indicate conditions differing materially from those of another Period into
which it is supposed to have had its existence prolonged, and so far removed as
to have almost its entire Fauna formed upon a different type, would in all pro-
bability be affected in some degree by the change, so as to produce a slight alteration
in its calcareous covering, such as would constitute what is called a variety, and these
characters might become permanent under the continuance of those altered conditions ;
but should we not be permitted so to undermine specific integrity, we may at least be
allowed a latitude in variation, that is ordinarily conceded to the examination of
existing forms, and the differences between the shells of the two periods, which are
here considered as identical, is less than is oftentimes presented to us by individuals
of undoubtedly the same species in the Crag deposits; even in those recent species
that appear to be admitted by almost general consent, as having originated in the
earliest Tertiary Periods, a difference may be detected between the older and the more
recent specimens, showing those animals that are apparently possessed of capabilities
of endurance beyond their contemporaries, have not been able to maintain in strict
integrity the supposed unvarying characters originally impressed upon them; all, how-
ever, that is contended for here is, that no greater restriction in regard to the limits of
variation ought to be imposed upon the line of specific demarkation, merely from
differences in Geological Periods, than is granted to deviations among specimens from
the same deposit.

BIVALVIA. 75

Arca,* Linneus, 1758.

PARALLELOPIPEDUM. Klein, 1753. Byssoarca. Swainson, 1820.
ANOMALOCARDIA, Id. (not Schum). Navicuta. Blainv., 1825.
Crpora. Browne, 1756. RuompBorpes. Id.
PrectuncuLus. Adanson, 1757. ScapHuLa. Benson, 1834, not Swainson.
Arca. Linneus, 1758. Arcina? Gray, 1840.
AmycpaLumM. Chemnitz, 1784. Barpatra. Id.

Darune and DapHNopERMA. Poli, 1795. Lunarca? Id.

Trisipos. Bolten, 1798. LitHarca. Jd. 1844.
Cucutt@a. Lam., 1801. SENILIA. Id.

Arcitrs. Martin, 1809. Scapuura. Id.

Trists. Oken, 1815. Isoarca. Miinster, 1843.
Cypuoxis. Rafinesque, 1819. ANDARA. Gray, 1847.
ArcaciTEs. Schlot., 1820. Scapuarca. Id.

Generic Character. Shell inequilateral, generally equivalve, more or less quadrate
or trapezoidal, sometimes closed; at others, with an opening at the ventral margin,
thick and strong; externally striated or costated. Umbones distant. Hinge linear,
with numerous Close-set interlocking teeth. Ligamental area generally large and
broad, with angular grooves. Palleal impression entire.

Animal oblong, edges of mantle disconnected, simple or fringed, without siphonal
tubes, a large and bent elongated foot with a groove capable of expanding into a disk-
like form, and a gland at its base for the production of a byssus. Byssus compact.

Animals of this genus generally spin a substance for their attachment, but many
are found located in rocks or holes of shells. Some species have a considerable
opening at the ventral margim, in consequence of which, those more strongly marked
with that character were placed in a separate genus, under the name Bysso-arca ;
but im individuals of the same species, this opening is subject to great variation, being
large in some, while in others it is nearly obliterated.

M.gNyst has published a synoptical table of this genus, in which he has enume-
rated 459 species, 162 of these are recent, whilst the others are extended through
almost every Period, commencing with the Upper Silurian, and ranging through all
the intermediate Formations: although some few of these, are probably, only varieties,
such an extensive genus might naturally be expected to have a large geographical
range; the recent species are found in all parts of the world, though not equally dis-
tributed, nearly one hundred being found in the equinoctial regions; and its vertical
range, is also very extensive, some bemg found under stones at low water mark,
while others have been met with attached to rocks as deep as eighty fathoms.

* Etym. So called from its Boat-like form.

76 MOLLUSCA FROM THE CRAG.

]. ARCA TETRAGONA, Poli. Tab. X, fig. 1, a—d.

ARCA TETRAGONA. Poli, Test. Sic., vol. ii, p. 137, pl. 25, figs. 12, 13, 1793.
— — Turt. Brit. Biv., p. 166, pl. 13, fig. 1, 1822.

— — Payr. Cat. Moll. Cors., p. 61, No. 105, 1826.

— —_ Desh. 2d ed. Lam., t. vi, p. 461, 1835.

_ _ Forbes. Malac. Monen., p. 41, pl. 3, 1838.

— — Id. Report on Agean Invert., p. 181, 1843.

— — Phil. En. Moll. Sic., vol. i, p. 57, 1836.

— — Reeve. Conch. Icon. Monog. Arca, pl. 15, fig. 100, a—d.
— — ? Menke. Moll. Nov. Holl. p. 37, No. 208, 1843.

— Nox. Mont. Test. Brit., p. 139, pl. 4, fig. 3, 1803.

— — Don. Brit. Shells, vol. v, pl. 158, figs. 1, 2, 1804.

— — Brown. Brit. Conch. Mlust., pl. 25, figs. 1-3, 1825.

—— — &. Wood. An. and Mag. Nat. Hist., vol. iv, New Series, p. 231, pl. 13, figs. 2,

& 2a, 1840.

— — Morris. Cat. of Brit. Foss., p. 78, 1843.

— Fusca. Mont. Test. Brit. Sup., p. 51, 1808 (not Reeve).

— — W. Wood. Ind, Test., p. 45, pl. 9, fig. 14, 1825.

—- — Flem. Brit. An., p. 397, 1828.

— — Thorpe. Brit. Mar. Conch., p. 101, 1844.

— carpissa. Desh. 2d ed. Lam., t. vi, p. 463, 1835.

_ — Alder, Cat. Moll. North. and Durh., p. 79, 1848.

— wavicunaRis. Desh. 2d ed. Lam., t. vi, p. 462, 1835.

— — Phil. En. Moll. Sic., vol. ii, p. 42, 1844.

— — Lovén. Ind. Moll. Seand., p. 33, 1846.

— Britannica. Reeve. Conch. Icon. Monog. Arca, pl. 15, fig. 98.

— — Nyst. Tab. Syn. des Arches. Viv. et Foss., p. 14, No. 47, 1847.
— papiLLosa. Smith. Mem. Wern. Soc., vol. viii, pl. 1, fig. 19, 1838.
Batanus Bexionir. List. Hist. Conch., lib. ii, fig. 207, 1687.

Ency. Meth., pl. 308, fig. 3, a—é.

Spec. Char. Testé oblonga, valdé inequilaterd, costato-striatd, et transversim
decussatd, anticé rotundatd, postice angulatd ; carind posticd eminente, acutd ; apicibus
remotis incurvis ; margine ventrali hiante.

Shell oblong, very inequilateral, with costated striz, decussated by distinct lines
of growth; anterior side rounded, posterior angulated, with a prominent Keel or
ridge from the umbo to the posterior ventral margin ; umbones distant, incurved ;
ventral margin gaping.

Largest diameter, \ inch.

Locality. Cor. Crag, Sutton, Ramsholt, and Sudbourn.

Red Crag, Sutton. Recent, Scandinavia, Britain, and Mediterranean.

Very small specimens are by no means rare in the Coralline Crag; but I have met
with very few examples of the adult shell. These small or young specimens are very
regular in form, being much elongated transversely, of a somewhat rhomboidal shape,
the anterior side slopes a little from the extremity of the hinge line, rounding at the
ventral margin, while the posterior side is angular, pointed and projecting ; the ventral

BIVALVIA. vi

margin being nearly straight, or with a very little inflection. A full grown specimen
found in the Red Crag (fig. 1, a—#), is very regular in form, and all its ornamental
strie beautifully preserved: the rays or costulated strize are close and numerous
upon the posterior half of the outer side of the umbonal ridge, while they are
larger and more distant upon the anterior half; and within the prominent ridge,
that slopes from the umbo to the posterior ventral margin, the rays are large
and few, amounting to about four or five, and are placed in pairs; they project
beyond the posterior margin, giving it a jagged or indented edge. A long line
of teeth or crenulations occupy the edge of the hinge margin, they are numerous
and vertical on the anterior or shorter side, fewer or more distant, and strongly
inclining on the posterior side. The ligamental area is large and concave removing
the umbones far apart; this space is ornamented with deep and angular lines diverg-
ing from the umbo, in some they are few and deeply impressed, while in others they
are morenumerous. One specimen in my Cabinet, from the Coralline Crag at Gedgrave
(fig. 1, c), precisely resembles the distorted specimens found occasionally upon our
own Coast, in holes or crevices of rocks, and in which the regularity of form has
been interrupted, and the surface much abraded by frequent movements in a con-
fined position, thus producing so great an alteration in the exterior of the shells as to
have induced some authors to consider them distinct. In some of these full grown
and distorted specimens, the ventral margin is deeply indented or sinuated. They
are said by British Conchologists to be regular in form when free, and only distorted
when confined to the crevices of rocks.

I have entered it among my synonyma upon the authority of Menke, who gives it
as one of the existing species from the North Western Coast, New Holland. He has
enumerated several other European shells from that part of the world.

2. ARCA LACTEA, Linnaeus. Tab. X, fig. 2, a—é.

Arca LacTEA. Linn. Syst. Nat., ed. 12, No. 173, p. 1141, 1767.
— — Da Costa. Brit. Conch., p. 171, pl. 11, fig. 5.
— — Chem. Conch. Cab. t. vii, p. 200, t. 55, fig. 547, 1784.
= — Don. Brit. Shells, vol. iv, pl. 135, 1803.
_ a W. Wood. Ind. Test., p. 45, pl. 9, fig. 24, 1825.
— — Brown. Illust. Conch. Gr. Brit., pl. 25, fig. 6, 1827.
— — Mawe. Linn. Syst. Conch., pl. 13, fig. 4, 1823.
= — Phil. En. Moll. Sic., vol. i, p. 57; vol. ii, p. 42.
- —_ Forbes. Rept. on Aigean Invert., p. 181, 1843.
= — Reeve. Conch. Icon. Arca, pl. 17, fig. 116.
— = Dujard. Mem. Geol. Soc. de France, t. ii, pt. 2, p. 266, 1837.
— — Hanley. Recent Shells, vol. i, p. 154, pl. 9, fig. 24.
— mopioLtus. Poli. Test. Sic., vol. ii, p. 137, pl. 25, figs. 20, 21, 1795.
== — Turt. ed. Linn., vol. iv, p. 251, 1806.
— PERFORANS. Turt. Conch. Dict., p. 9, 1816.
= — Id. Brit. Biv., p. 169, t. 13, figs. 2, 3, 1822.
— Garmarpil. Payr. Cat. Moll. Cors., p. 61, pl. 1, figs. 36—39, 1826.

78 MOLLUSCA FROM THE CRAG.

Arca GarmarpiI. Desh. Exp. Sci. Algiers Moll., pl. 124, figs. 8—11.

— Qvoyrm. Payr. Cat. Moll. Cors., p. 62, pl. 1, figs. 40—43, 1826.

— _— Desh. Append. to Lyell’s Prine., Ist ed., vol. ili, p. 10, 1833.

— uactanga. S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 232, pl. 13, fig. 3,

1840.

— — S. Wood. Catalogue, 1840.

cone — Morris. Cat. Brit. Foss., p. 78, 1843.

— noputosa? Broc. Conch. Foss. Subap., p. 478, t. ii, fig. 6, a—c, 1814.
— ? Dubois. Wolhyn. Podol., p. 64, pl. 7, figs. 21, 22, 1831.
— striata. Reeve. Conch. Icon. Arca, pl. 17, fig. 121.

List. Hist. Conch., lib. iii, fig. 69, 1685.

Dale. Hist. and Antiq. of Harwich, p. 291, 1730.

Adanson. Voy. au Senegal, p. 250, pl. 18, fig. 8, 1757.
not Arca LacTEA, Brander. Foss. Hant., pl. 8, fig. 106.

Spec. Char. Testa ovato-oblongad, interdum subquadratd, anticé rotundatd, posticé
oblique truncata; decussato-striatd ; striis radiantibus eminentioribus ; area cardinali
mediocre profunda ; margine ventrali subrecta.

Shell ovato-oblong, sometimes nearly square, anterior side rounded; posterior
obliquely truncated; covered with striz, crossed by transverse lines of growth;
radiating strie the most prominent; cardinal area not large, with a rounded or obtuse
ridge from the umbo backwards ; ventral margin nearly straight.

Longest diameter, % of an inch; height, $ an inch.

Locality. Cor. Crag, Sutton.

Red Crag, Sutton, Walton Naze. Recent, Britain and Mediterranean.

In the sandy portion of the Coralline Crag at Sutton, a locality that has yielded so
many of the smaller and more fragile species of Mollusca, numerous small or young
individuals of this species may be obtained. My largest specimen was found in the
Red Crag at Walton Naze, and measures an inch in its transverse or largest diameter
but it is an old and somewhat mutilated individual.

When my Catalogue was compiled this was considered to be a distinct species, in
consequence of a difference in the size of the ligamental area, as in the Crag shell it is
smaller than in the generality of recent specimens, the resemblance was, however, so
great in all other respects, that the name of J/actanea was given from its near
relationship. I have since seen specimens of the recent shell in which this distinction
is lost, and have therefore now united it with the long-known recent species. My
specimens from the Crag are very regular in form, and I have not met with any
fossils resembling the distorted varieties which have been erected into species by
Payraudeau under the names of 4. Quoyii and A. Gaimardi, the greatest variation
being slight differences in proportional dimensions, some occasionally being rather
more transverse than others.

Arca nodulosa, Miller, given as an inhabitant of the Seas of Norway, by Dr. Lovén,
corresponding probably with the Calabrian fossil 4. aspera, Phil., appears to differ
from our shell in being larger and broader on the posterior half, with a more deeply

BIVALVIA. 79

and regularly decussated exterior, but with a small and narrow ligamental area. Arca
nodosa, Brocchi, seems to belong to our present species, as does also, in all probability,
the one figured and described under that name by Dubois, judging from his short
description and small figure.

ARCA PECTUNCULOIDES, Scacchi. ‘Tab. X, fig. 3, a—d.

ARCA PECTUNCULOIDES. Scac. Ann. Civ. delle Due Sicil., vol. vi, p. 82, 1834, fide Mys¢.
a= = Scacchi. Notizia, p. 25, t. 1, fig. 12, sec. Phil.
a — Phil. En. Moll. Sic., vol. ii, p. 44, t. 15, fig. 3, 1844.
— a Jeff. Ann. Nat. Hist., vol. xix, p. 313.
= — Lovén. Ind. Moll. Scand., p. 34, 1846.
= — ? Mich. Prec. Faun. Mioc., t. 3, fig. 14, 1847.
— — Sismonda. Syn. Meth. Pedm. Foss., p. 16, 1847.
— — Nyst. Tab. Synop. des Arches Viv. et Foss., p. 54, No. 300, 1847.
— RARIDENTATA. S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 232, pl. 13,

fig. 4, 1840.
— —_ Thompson. Ann. Nat. Hist., vol. xviii, p. 385.
— — S. Wood. Catalogue, 1840.
— — Morris. Cat. Brit. Foss., p. 78, 1843.
= es Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 241, pl. 45, fig. 8,
1849. |

— pusitta. Nyst. Coq. Foss. de Belg., p. 261, pl. 20, fig. 6, 1844.

CucuLL@a PusILLa. Nyst. Rect. Coq. Foss. Prov. d’Anv., p. 14, pl. 3, fig. 55, 1835.

Spec. Char. Testé parva, inequilaterd, ovato-rhomboided, gibbdé; striis exrguis,
decussatis; area ligamentt parva, apicibus refleais ; cardine recto, utringue tridentato ;
margine ventralt subsinuato.

Shell small, inequilateral, ovato-rhomboidal, gibbous; ornamented with fine
decussating striz; ligamental area small, umbones inflected; hinge line straight,
furnished with three teeth on each side; ventral margin subsinuated.

Largest diameter, 3th of an inch.

Locality. Cor. Crag, Sutton. —_ Recent, Britain, Mediterranean, and Aigean Seas.

This elegant little shell is another species, but rarely found in the British Seas, and
which may perhaps be one of those we might consider to be in a specific decline, or
the dying out of what was once largely developed in these latitudes. In the Coralline
Crag at Sutton this is one of the most abundant fossils, and I have obtained the
separated valves by hundreds.

It is stated by the authors of the ‘ Hist. of Brit. Moll.’ to be slightly inequivalved.
In the fossil state 1 have never been able to obtain a specimen with the valves united.
There does not appear to be’ any doubt of its identity with the living British species,
and a single valve obtained from a considerable depth in the Adgean Sea, obligingly
given to me by Professor E. Forbes, corresponds in all respects with the Crag shell.

Where the specimens are so abundant, differences of form may naturally be
expected, some may be selected that are more elongated and less tumid than others,

80 MOLLUSCA FROM THE CRAG.

and my two most extreme variations are here represented: all give indications of an
opening for a byssus by an indentation or sinuosity on the anterior side of the
ventral margin ; this character is imperfectly represented in the Mediterranean fossil
by Philippi, nor is it well shown in that by Nyst, although the probabilities are they
all belong to the same species: both of these authors speak of their shell as being by
no means abundant. When perfect, it is ornamented with distinct radiating strie,
the largest and most prominent at the two extremities; they are crossed by lines of
growth somewhat irregular, and the surface is imperfectly cancellated. Upon the
hinge line, on the anterior side, are three or four rather large and prominent teeth,
which slope at an angle of about 45°, while those on the posterior, amounting to the same
number and equally prominent, are nearly parallel to the hinge margin; in some
small or young specimens, these teeth or prominences do not amount to more than
two on each side, and all so arranged that when the valves are united, the one set
interlock with those of the opposite valve. The place for the ligament is very small,
and in perfect specimens there may be seen an entire row of crenulations just
within the ventral margin of the shell; and a prominent ridge slopes down the interior
from beneath the umbo, probably formed by the inner edge of the adductor muscle
on the anterior side. In old specimens the mark of the mantle is deeply impressed,
running parallel to the outer edge.

Nucuta,* Lamarck, 1799.

GLYCIMERIS (sp.). Da Costa, 1778.
TELLINA and Donax (sp.). Gmel.
Arca (sp.). Linn.

Potyoponta. Megerle, 1811.

Generic Character. Shell equivalve, very inequilateral, ovato-trigonal, generally
transverse, closed, nacreous, and in the recent state covered with an epidermis; often
smooth, sometimes striated, or variously ornamented upon the exterior: hinge line
more or less angular, furnished with a series of sharp, elevated, and angulated teeth,
arranged on each side of the umbones, interrupted by a central and internal spoon-
shaped projection, upon which is placed the ligament. Impression by the mantle
without a sinus.

Animal of the form of the shell, having the edges of its mantle plain dis-
connected, and without siphonal tubes. Foot large, and capable of expanding into an
ovate, pedunculated disc, with fimbriated edges, and by means of this organ it is
capable of a considerable degree of locomotion, creeping like a Gasteropod at the
bottom of the water.

* Etym. Nucula, a little nut.

BIVALVIA. 81

Since the original establishment of the genus by Lamarck, it has been much
curtailed, and is now restricted to those shells with a pectiniform or denticulated hinge,
having the posterior portion, as it were, cut off; the lines of denticulations forming
nearly a right angle, and the animal being without the posterior siphonal tubes ;
consequently there is no indentation in the impression formed by the muscles of the
mantle.

The genus thus restricted is in a recent state rather sparingly distributed, although
found in the seas of both hemispheres. As fossil, it has been obtained low in the
Secondary Formations.

The species in a living condition are mhabitants of the sea at all depths, some being
found near low water mark, while others are truly pelagian, and have been observed in
the deepest regions Mollusca are known to frequent. Mr. Garner, in his ‘ History
of the Lamellibranchiata,’ says, there is a distinct pinnate process in the mantle of
the animal, for the purpose of secreting the numerous teeth of the hinge; these teeth
are prominent, sharp pointed, and angular, the angle being directed towards the
umbo from both sides.

1. Nucuta Ltavieata, J. Sowerby. Tab. X, fig. 8, a—d.
NucuLa La&vieaTa. J. Sow. Min. Conch., t. 192, figs. 1, 2, 1818.
— — Goldf. Pet. Germ., vol. ii, p. 157, pl. 125, fig. 19, a—e.
S= = S. Wood. Mlust. Mag. Nat. Hist., New Series, vol. iv, p. 296, 1840.
— — Id. Catalogue, 1840.
— — Nyst. Add. 4 la Faune Conch. de Belg. (Bull. Acad. de Brux, t. ix,
p. 450), 1842.
— — Morris. Cat. Brit. Foss., p. 94, 1843.
— — Nyst. Coq. Foss. de Belg., p. 228, pl. 17, fig. 8, a—b, 1844.

Spec. Char. Testé transversdé, ovatd, valde inequilaterd, levigatd, tenui, mar-
garitaced, clausd; anticé brevi, subangulatd ; postice productiore, rotundatd ; margine
ventralt integerrimo. .

Shell, transverse, ovate, very inequilateral, smooth, thin, nacreous, and closed ;
anterior side short, sloping, or angulated; posterior much produced and rounded ;
ventral margin without crenulations.

Longest diameter, 12 ths of an inch ; hezght, 1 inch.

Locality. Cor. Crag, Sutton..

Red Crag, Walton Naze.

This is the largest species of the genus that I am acquainted with, either in the
recent or fossil state, it appears to have attained its full development in the Red
Crag, as in the Deposits of that Period at Walton Naze specimens are by no means
rare ; it is found also in the older or Coralline Crag, where, however, they are few in
number and small in size.

M. Deshayes has quoted this as synonymous with JV, ovata, an Kocene species from

11

82 MOLLUSCA FROM THE CRAG.

the Paris Basin ; there are, however, marked differences between the two, sufficient to
keep them specifically distinct. The older shell has a crenulated margin, with other
characters of minor importance by which it may also be distinguished, while the
Crag one has its margin perfectly smooth. A shell in the Cabinet of Mr. D’Urban,
found in the Eocene Formation at Bracklesham, strongly resembles our species, in
having its margin free from the shghtest appearance of crenulations, but it differs in
being rather less transverse and more tumid, with the posterior ventral margin less
angular and pointed, approaching in the last character the specimens from the
Coralline Crag; these differences appear to be sufficient for specific distinction, and,
as yet, I have not seen any shell with which it can be fairly identified; the exterior of
our Crag shell is smooth and glossy in specimens the surface of which has not been at
all eroded, and it was, in a recent condition, most probably covered with an epidermis.
On the anterior dorsal margin there is a rather narrow row of prominent angular teeth,
varying from 20 to 35; while on the short or posterior side the teeth are broader and
closer, and in number about 10 or 12, with a deeply impressed lunule on the posterior
or shorter side. There is no other exterior marking than the lines of growth, but
when the glossy surface is removed, the shell appears to have a radiated fibrous
structure, and the interior is often faintly rayed; a long subangular depression for
the ligament curves inwardly towards the anterior, adhering to the inner edge of the
dorsal margin. ‘The dorsal as wellas the ventral margins are rounded, giving an ovate
form to the shell, only truncated on the posterior side, where the ventral margin forms
a sort of incipient rostrum, connecting it in that character with the following genus,
though less so than in some other species.

2. Nucuta CospBoipim, J. Sowerby. Tab. X, fig. 9, a—é.

Nucuta CospoLpim®. J. Sow. Min. Conch. t. 180, fig. 2, 1818.
a _ Woodward. Geol. of Norf., p. 44, 1833.
— — Lyell. Mag. Nat. Hist., New Series, vol. iii, p. 328, 1839.
— — Id. Elem. Geol., p. 299, fig. 113, 2d. ed., 1841.
— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 295, 1840.
— — Id. Catalogue, 1840.
— _ G. B. Sowerby. Genera, No. 17, fig. 9.
—_ — Forbes. Geol. Surv. Gr. Brit., p. 83, 1846.
— — Morris. Cat. Brit. Foss., p. 94, 1843.

Spec. Char. Testa transversd, oblique-ovatd, convexd, clausé ; irregulariter radiatd,
aut lineolis flecuosis ornatda ; intus sepé incrassatd ; margine integerrimo.

Shell transverse, obliquely ovate, convex, thick and closed; sculpture on the
exterior, with irregular radiations or lines in a divaricating or zig-zag direction ;
interior often irregularly thickened, margin smooth.

Longitudinal diameter, \+ inch. Height, 1 inch.

Locality. Red Crag, Sutton, Bawdsey, near Ipswich, and Felixstow.

Mam. Crag, Thorpe, Bramerton, Chillesford, Bridlington.

BIVALVIA. 83

This species has not, as yet, I believe, been found in any Formation older than the
Red Crag, in which. it does not seem to have been very abundant, but in the Deposits
of the succeeding period it may be obtained in large numbers, in the portion of that
Formation resting upon the Red Crag at Chillesford, where the valves are sometimes
found united, and in their natural position.

There is no species known with which this is likely to be confounded, as its
peculiar sculpture differs from that of any recent MVucule inhabiting the Northern
Hemisphere, or of any of our well-known Tertiary species. Two fossils found in the
Cretaceous Formations (JV. é¢virgata and ornatissima), possess similar ornament, and a
recent species has been ‘also obtained from a considerable depth off the Cape of Good
Hope, which is covered with zig-zag striz, these however have no specific relationship
with our shell.

This species, although one of the finest belonging to the genus, has not attained
quite so great a magnitude as the preceding one, my largest specimen does not
exceed one inch and an eighth in its transverse or largest diameter, while the
other has reached to an inch and three eighths. Like most of the shells from
the Crag, it varies somewhat considerably in its proportional dimensions. In those
which are most tumid, the diameter is less from the dorsal to the ventral margin, than
it is in those which are more compressed. The number of teeth are generally from
sixteen to eighteen on the anterior side, with about ten upon the shorter or posterior
slope, they are prominent and sharp, of an angular form, and interlocking, and the
fossette for the ligament is large, projecting inwardly, inclining beneath the dorsal
edge towards the anterior side, and the umbo is terminal, and somewhat pointed.
This species is sometimes much thickened internally in aged specimens, forming
deeply indented impressions by the adductors, which are of a sub-circular form
inclining to oval, and the marginal impression of the mantle is then ornamented with
radiations like those in some of the Zwcine, but the margin of the shell is smooth,
and free from crenulations.

This pretty shell is ornamented upon the exterior with irregularly divaricating
strize, which generally, in the young state, have only one series of diverging lines, but
in the centre part of the older specimens they are more irregular, and become zig-zag,
with two, three, or more angular points of divergence, the radiations are large and
rounded, and crossed by transverse or very perceptible limes of growth, and the
shell when living was probably covered by an epidermis.

In some specimens the umbo is much eroded, while in others it is quite perfect.

84 MOLLUSCA FROM THE CRAG.

3. Nucuta TENvIS, Montague. Tab. X, fig. 5, a—d.
Arca TENUIS. Mont. Test. Brit. Suppl., p. 56, t. 29, fig. 1, 1808.
— — Pennant. Brit. Zool., vol. iv, p. 218, fide Gould.
— — Dillw. Desc, Cat. Rec. Shells, p. 246, 1817.
- _ Turt. Conch. Dict., p. 11, 1819.
— — W. Wood. Ind. Test., Arca, p. 47, pl. 10, fig. 45, 1825.
Nueva TENUIS. Turt. Brit. Biv., p. 177, 1822.
— — Flem. Brit. Ann., p. 402, 1828.
SS — Brown. Illust. Conch. Gr. Brit., pl. 25, fig. 13, 1827.
_ — Gould. Inv, Massach., p. 105, fig. 64, 1840.
_ _— Moller. Ind. Moll. Groén., p. 17, 1842.
—_ — Mae Gill. Moll. Aberd., p. 244, 1843.
— — Morris. Cat. Brit. Foss., p. 95, 1843.
— _ Thorpe. Brit. Mar. Conch., p. 105, 1844.
— — Forbes. Geol. Surv., vol. i, p. 83, 1842.
— — Hanley. Rec. Shells, vol. 1, p. 171, pl. 10, fig. 45.
—_ — Alder. Cat. Moll. North. and Durh., p. 79, 1847.
— — Lovén. Ind. Moll. Scand., p. 34, 1846.
— _ Forb. and Hanl. Uist. Brit. Moll., vol. ii, p. 223, pl. 47, fig. 6 (Animal),
pl. P, fig. 5, 184 9.
— TENERA. S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 295, pl. 14, fig. 2.
— Ryckuoxtrana? Myst. Coq. Foss. de Belg., p. 233, pl. 15, fig. 10, a—é, 1844.
— oecrpreNs. Phil. En. Moll. Sic., vol. ii, p. 48, t. xv, fig. 15, 1844.
— vera. Blanding. MSS. fide Gould.

Spec. Char. Testa ovatdé, trigono-ellipticd, levigatd, tenui, latere antico subangulato ;
lunula parum distinctd, margine ventrali arcuato, integro.

Shell ovate, elliptically triangular, smooth, and thin; anterior side produced,
roundedly angular ; junule not well defined, ventral margin smooth.

Diameter, $ an inch.

Locality. Cor. Crag? Gedgrave.

Red Crag, Bawdsey.
Mam. Crag, Bridlington, Chillesford.
Recent, Mediterranean, Britain, Scandinavia, and North America.

Two specimens of a species resembling this are in my Cabinet, they were obtained
from the Coralline Crag, but are too imperfect for correct determination. In the
Red Crag Formation it has undoubtedly made its appearance, several individuals were
found by myself, and in the sandy deposit at Chillesford it is an abundant shell
seemingly increasing in numbers towards the present Period. Its greater tenuity and
more ovate form will distinguish this from JV. nucleus, as well as the absence from the
margin of all crenulations. It differs from the young of JV. /evigata in being less
transverse, that species having a greater diameter when measured from the anterior
to the posterior margin, the hinge line also forms a greater angle than in ¢enwis, and
the posterior termination is somewhat produced. In this species the anterior dorsal
margin is more rounded than in any of the others, so is the ventral margin,

BIVALVIA. 85

giving a more ovate form to the outline. It has a rather narrow row of denticles on
both sides, those upon the anterior are from ten to twelve in number, with about six
or eight upon the shorter or posterior side. A shell somewhat resembling this is
found in the Upper Marine, in Headon Hill, being free from crenulations at the
margin, and is also a thin shell, with a similar ovate contour, though seemingly
rather more pointed at the posterior extremity, but my specimens of the Eocene
fossil are scarcely in a sufficiently good state of preservation for a fair comparison.

A specimen of this species, found at Bridlington, was obligingly forwarded to me
for examination by Mr. Leckenby.

4. Nucuta nuc.LeEus, Linneus. Tab. X, fig. 6, a—d.
Arca NuctEus. Linn. Syst. Nat., ed. 12, No. 184, p. 1143, 1767, not Brander.
— — Chem. Conch. Cab., t. vii, p. 241, t. 58, fig. 574, 1784.
— — Don. Brit. Shells, vol. ii, pl. 63, 1801.
— — Broc. Conch. Foss. Subap., vol. ii, p. 480, 1814.
— — W. Wood. Ind. Test., p. 47, pl. 10, fig. 42, 1825.
Nucuta nucLEus. Turt. Brit. Biv., p. 176, t. 13, fig. 4, 1822.
— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 294, pl. 14, fig. 1,

1840.
— — Thorpe. Brit. Mar. Conch., p. 105, p. 74, 1844.
= = Lovén. Ind. Moll. Scand., p. 34, 1846. * é
= = Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 215, pl. 47, figs. 7, 8,
1849.

— MAaARGARITACEA, Lam. Syst. des An. s. Vert., p. 115, 1801 (mostly).

a — - G. B. Sowerby. Genera, No. 17, fig. 7.

— — De Blaimv. Malac., pl. 75, fig. 5, 1825.

= — ? Bast. Mem. de la Soc. d’Hist. Nat., t. 2, p. 78, No. 2, 1825.

os = Payr. Cat. Moll. Cors. p. 64, 1826. ;

== — Brown. Illust. Conch. Gr. Brit., pl. 25, fig. 12, 1827.

= — Dubois. Conch. Foss. Wolhyn. Podol., p. 66, t. 7, figs. 35, 36,

1831.

== = Goldf. Pet. Germ., vol. ii, p. 158, t. 125, fig. 21, a—d.

— — Phil. En. Moll. Sic., vol. i, p. 64, t. v, fig. 8, 1836.

= = Bronn. Leth. Geol., vol. ii, p. 929, t. 39, fig. 5, a—e, 1838.

= — Swains. Malac., p. 382, fig. 125, f—g, 1840.

= — G. B. Sow., Jr. Conch. Man., fig. 137, 1842.

= — Forbes. Report on Aigean Invert., p. 180, 1843.

— — Sism. Syn. Meth. An. Inv. Piedm. Foss., p. 15, 1847.

— arcGEenTEA? Brown. Illust. Conch. Gr. Brit., pl. 25, figs. 14, 15, 1827.
GLYCIMERIS ARGENTEA. Da Costa. Brit. Conch., p. 170, pl. 15, fig. 6, 1778.
DonaX ARGENTEA. Gmel. Syst. Nat., p. 3265, 1788.

Ency. Meth., pl. 311, fig. 3, a—d.

Spec. Char. Testa obliqud, ovata, transversd, subtriangulart, levi, aut obsolete striata ;
dentibus cardinalibus acutis ; margine crenulato.

Shell obliquely ovate, transverse, slightly triangular, smooth or obsoletely striated ;
hinge with numerous, sharp, and erect teeth ; margin crenulated.

86 MOLLUSCA FROM THE CRAG.

Diameter, 5ths of an inch.
Locality. Cor. Crag, Sutton, Ramsholt, Sudbourn, Gedgrave.
Red Crag, Sutton, Bawdsey.
Recent, Mediterranean, Britain, and Scandinavian Seas.

Specimens of this species may be plentifully obtained in the lower or Coralline
Crag Deposit, especially at Gedgrave, where it appears to have been abundant, and
the numerous prominent and interlocking teeth being favorable for the preservation
of the valves in their natural position, they are frequently found united.

Considerable variation may be observed in comparing numerous individuals, some
of which closely approach what is called a species in the recent state under the name
of nitida, these differences consist principally in the proportionate dimensions, the
posterior side occasionally projecting more in some specimens than in others, and in
a greater solidity of shell. Faint traces of radiating striae ornament the exterior, they
are most visible near the margin, these lines are also visible within; the number of
crenulations slightly vary, being smaller and closer of course in the younger shell, and
in this state the contour is generally more rounded, the posterior side in particular
being less truncate.

A species somewhat closely allied to this is found in the upper part of the Older
Tertiary Formations at Hordwell, and in the Isle of Wight, but it is probably distinct.
It is thinner, the hinge line narrower and more regular, with fewer teeth, while in
LV. nucleus it is much broader as it approaches the anterior side, and the posterior
margin is rather less rounded.

A shell from the Upper Tertiaries of the United States strongly resembles this
species, and may, when better known, prove to be an identity.

5. NucuLA TRIGONULA, S. Wood. Tab. X, fig. 7, a—é.
Nucuna TriconuLta. S. Wood. Ilust. Mag. Nat. Hist., vol. iv, New Series, p. 295, pl. 14, fig. 3.
—— _ S. Wood. Catalogue, 1840.
— — Morris. Cat. Brit. Foss., p. 95, 1843.

Spec. Char. Testé minutd, trigonuld, levigatd, tumidd, margaritaced ; anticé sub-
angulata, posticée abbreviatd, margine ventral crenulato.

Shell small, trigonular, smooth, tumid, nacreous, anterior side roundedly angular,
posterior side very short, ventral margin crenulated. :

Longitudinal diameter, 2ths. Height, % of an inch.

Locality. Cor. Crag, Sutton.

About a dozen specimens with a much more angular or trigonal form than
is presented by the normal character of JV. nucleus, are in my cabinet from the Cor.
Crag, which induced me, when publishing the Crag species of this family, to consider
them as belonging to a distinct species, and I am still inclined to retain them as such,
from a very marked difference in the outline; it is nevertheless possible they may be
nothing more than specific variations, the result of some local condition ; they possess,

BIVALVIA. 87

however, sufficient difference to remain as specimens of a distinct variety, should they
be hereafter degraded from their isolated position. I have seen this species from the
Coralline Crag only, where JV. nucleus is found in abundance, and of all sizes, but
none of which seem to form any very close connection with this shell. British
Conchologists retain as distinct in this genus forms with less variation of character
than what is exhibited in our fossil specimens. .

Nucula nitida, Sow., appears to offer less pretensions for specific distinction, than are
presented by the angulated outline of our fossil, but probably the whole three will
merge into one species.

Nucula proxima of American authors, according to figures and descriptions, much
resembles our fossil, and is probably only another specific variation of a shell with
a very extended range.

Nucula radiata, Hanley, differs nothing in form from some of our Crag specimens,
and if it be a distinct species, may also have been in existence during that early
period.

Lepa,* Schumacher. 1817.

Nucuta (sp.). Lam., 1801.

Arca (sp.). Mont., 1803.
Lemputus. Leach, MS. 1819.
LemBvuLa (sp.). Risso, 1826.
Dacromya. Agass., 1839.

Youpia. Miller, 1842. Lovén, 1846.
Lepa. Lovén, 1846.

Moupia. Gray, 1847 (misprint).

Generic Character. Shell equivalve, inequilateral, elliptical or fig-shaped, posteriorly
more or less angulated or acuminated; smooth or transversely striated, covered by
an epidermis in the recent state ; umbones small, approximate. Hinge furnished with
numerous teeth arranged in a linear series, curved or slightly angular, interrupted in
the centre, or immediately beneath the beaks by a triangular fossette for the reception
of the ligament ; impressions by the muscles ovate or subangular, that by the mantle
more or less sinuated.

Animal transversely ovate, mantle open in front with simple, sometimes fimbriated,
margins ; foot large and discoidal, with serrated edges ; posterior side of the mantle
prolonged into two, partially united, slender and unequal siphonal tubes.

The genus Wucula, as established by Lamarck, was intended to contain all those
shells which had a hinge furnished with a line of sharp prominent teeth, separated
at the umbo by an angular depression for the reception of the ligament, and placed

* Etym., a proper name.

88 MOLLUSCA FROM THE CRAG.

within the margin of the shell, many of these have the posterior portion, as it were,
cut off or wanting, in which the animal is entirely without the protruding siphonal
tubes, and the impression of the mantle is therefore entire, this section constitutes our
genus JVucula, the type of which is 4rca nucleus, Linn. Many species formerly
included have a prolonged posterior side, making the shell sometimes nearly equi-
lateral, and the animal is then furnished with elongated siphonal tubes. This was
originally proposed by Schumacher, under the name of Leda, without his being at all
aware of the essential difference, as the only reason assigned for the division was that
these shells were more nearly related to Pectunculus (issai d’un Nouv. Syst. des Vers.
Test. p. 173).

Moller divided these latter or bilateral Nuculz into two genera, without, however,
any apparent distinction, either in the shell or animal; Vucula arctica, the species he
intended as the type of his genus Yol/dia, being furnished with a sinuated impression
like that of JV. minuta (the typical form of Leda), indicating the possession of
protruding siphons in the animal of that species: neither does the form of the exterior
present any essential difference.

These resemblances were more especially pointed out by Professor E. Forbes, in
his valuable essay in the first vol. of the ‘ Memoirs of the Geological Survey,’ p. 418,
where the two genera are united.

Shells possessing the form and characters assigned to this genus are found in some
of our oldest formations, and are continued through the more modern Periods.

]. Lepa LANCEoLATA, J. Sowerby. Tab. X, fig. 16, a—d.

NucuLta LANcEoLATA. J. Sow. Min. Conch., t. 180, fig. 1, 1817.

as = Morris. Cat. of Brit. Foss., p. 94, 1843.

— ospitonca. G. B. Sowerby. Genera, No. 17, fig. 6.

— — Woodward. Syn. Tab. Brit. Org. Rem., p. 15, 1830.

— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 296, 1840.

— arotica. Brod. and Sow. Zool. Journ., No. xv, p. 359, t. ix, fig. 1, 1829.

—_ — Middendorff. Mem. de lV Acad. Imp. de St. Petersb. p. 544, 1849.
Yorpia Artica. Méller. Ind. Moll. Groen., p. 18, 1842.

Spec. Char. Testa transversd, elongato-ovatd, inequilaterd, crassé ; anticé majiore et
latiore elliptico-rotundata, postice subrostratd ; externé striatd, striis transversis obliquis,
dentibus crassis angulatis.

Shell transverse elongato-ovate, inequilateral, thick and strong, anterior side the
larger and broader, elliptically rounded; posterior subrostrated ; externally striated,
striz broad and oblique, teeth thick and angulated.

Longitudinal diameter, 24 inches.

Locality. Red Crag, Bawdsey.

Mam. Crag, Chillesford. Recent, Arctic Seas.

BIVALVIA. 89

This species in the recent state appears to be restricted to colder regions of the
northern hemisphere, and is essentially a Boreal species. In the Red Crag it is by no
means abundant, and until the discovery of the native bed at Chillesford, resting upon
the Red Crag, it was considered a shell of great rarity in our cabinets, but at this latter
locality it may now be obtained in considerable numbers, and the specimens have
there seemingly reached their full development in regard to size, some of mine having
a magnitude of two inches and a quarter in the longest diameter. This and Mya
truncata are the most characteristic as well as the most abundant species in that
Deposit. The anterior side of the shell may be described as forming nearly half a
regular ellipsis, and the posterior side is smaller and rostrated; the pointed termi-
nation curving a little upwards; a large lanceolated corselet or flattened space occupies
nearly the whole length of the posterior slope, and a smaller or more narrow one is
generally to be seen at the dorsal margin on the anterior side; the number of teeth are
variable, generally about twenty on the posterior, and thirty on the anterior side, they
are large, prominent, sharp, and angular, with serrated edges, the lateral teeth
are more distant from each other than those nearer the umbo; this is the
number in the adult shell; in the younger state they are less numerous, additions
being made to their amount as the animal enlarges; a sinus with two or three
obsolete rays curves over the anterior side at some little distance from the dorsal
margin, produced probably by the protrusion of a peculiarly formed foot at that part
of the edge of the shell; coarse lines of growth cover the exterior, and these are
cut at a small angle by ridges which cross the shell in an oblique direction from
the anterior to the posterior ventral margin; but not extending over the dorsal
portion of the shell on either side: in some aged specimens, the interior is irregu- |
larly and ruggedly thickened, leaving deep impressions on those parts to which the
muscles of the animal were attached: that of the adductor on the anterior side is large
and angularly ovate, and not far from the extremity, the posterior one is smaller, and
situated more within the shell; the curve formed by the retrocession of the siphonal
tubes is rather variable, extending in some specimens as far as the middle of the
ligamental area. The principal variation to which this species appears to be subject is
merely in the proportional dimensions.

The name proposed by Mr. J. Sowerby has priority of date over that employed by
Lamarck for a very different species, which was published in 1819, and as such it
is retained here for the Crag Fossil; and for the shell, therefore, so called by
Lamarck, I would substitute that of cultrata.

12

90 MOLLUSCA FROM THE CRAG.

2. LeDA MYALIS, Couthouy. Tab. X, fig. 17, a—e.

Nucuta myauis. Couth. Bost. Journ. Nat. Hist., vol. ii, p. 62, pl. 3, fig. 7, 1839.
— _— Gould. Invert. of Massach., p. 99, 1841.
aoe — Dekay. Hist. New York Zool., p. 180,-pl. 13, fig. 219, 1843.
— opionca? Woodward. Geol. of Norf., p. 44, 1833.
— allied to optonea. Lyell. Mag. Nat. Hist., New Series, p. 328, 1839.
— opLoncoiprs. S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 297, pl. 14,

fig. 4, 1840.

== — Morris. Cat. Brit. Foss., p. 95, 1843.
— — Forbes. Mem. Geol. Surv., vol. i, p. 420, 1846.
— HYPERBOREA. Lovén, sec. Gould.

Youpta aneuLaRIs. Moller. Ind. Moll. Groenl., p. 19, 1842.

Spec. Char. Testé transversd, inequilaterd, elongato-ovatd, tenui; anticé elliptico-
rotundaté, postice subrostrata ; levigata ; dentibus mediocriter angulatis.

Shell transverse, inequilateral, elongato-ovate, thin, and externally smooth;
anterior side roundly elliptical, posterior subrostrated; externally smooth; teeth
moderately angulated. :

Longitudinal diameter, 13 inch. Height, 1 inch.

Locality. Red Crag, Sutton and Butley.

Mam. Crag, Chillesford and Bramerton. Recent, North America.

This species, like the preceding one, appears in the recent state to be confined
to the colder regions of the globe, and as a fossil has been found only in the
newer Tertiaries in this country. In the Red Crag I have met with but very
few specimens, while at Chillesford it may be obtained in abundance, and is by no
means scarce, I believe, in the Estuary portion of the Mammaliferous Crag at
Bramerton. It is readily distinguished from JL. /anceolata, in being more equi-
lateral, the posterior portion is comparatively larger, and it wants the peculiar
diagonal ridges which ornament the surface of that shell; nor does it appear
even to attain to such dimensions, my largest specimen being under two inches in
its transverse or longest diameter, neither is it ever so thick a shell. A specimen
obtained in the Red Crag at Sutton is more elongated or attenuated than those
usually found at Chillesford, and it approaches in that character Z. /imatula of the
American Seas (fig. 17, c); but that species is rather more elegantly formed, and
more rostrated, with a greater curvature at the posterior termination. Our shell is
covered with concentric striz or lines of growth, but not in regular ridges, and there
is not so distinct a sinus on the anterior side, as in L. /anceolata, although in some
specimens a radiating line traverses that side of the shell from the umbo, which line is
produced by a slight interruption to the regular curve of the margin: a large corselet
is well defined on the posterior side, and the ligamental pit is comparatively larger
than in L. imatula. The shell is sometimes thickened in the interior, though never

BIVALVIA. 91

so much so as in ZL. /anceolata, and the muscular marks are then deeply impressed,
those produced by the adductors are of a subovate form, and are unequal in size, the
anterior one being the larger, and the sinus formed by the mantle extends about as far
inwardly as the posterior part of the ligamental pit, which is broad and contracted in
the centre.

Our shell appears to correspond with the recent American species to which
it is here assigned, in all its characters, excepting size. Dr. Gould gives the dimen-
sions of his shell as 1,4; inch in its largest diameter, which is considerably less than
the magnitude to which our fossil has attained. In the recent state it is generally
eroded at the beaks; our fossil does not appear to have been at all acted upon at
that part, it is there quite perfect.

A shell from the Antarctic Seas, WV. Mightsii, Couthouy, strongly resembles our
British fossil.

3. Lepa semistriATA, S. Wood. Tab. X, fig. 10, a—dé.
Nucuna semistTr1atTa. S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 297, pl. 14,
fig. 5, 1840.
— wnirma. Nyst. Rech. Coq. Foss. d’Anv., p. 16, pl. 3, fig. 62, 1835, (not Brocchi.)
— opeEpREsSA. Nyst. Coq. Foss. de Belg., p. 220, pl. 15, fig. 7, 1844.

Spec. Char. Testdé transversd, ovato-ellipticd, subequilaterd, compressd, tenuissim,
Jragili ; antice rotundato-ovaté et levigatd, posticé subrostraté et transversim striata ;
natibus approximatis, margine integerrimo.

Shell transverse, elliptically ovate, subequilateral, compressed, thin, and fragile ;
anterior side roundly ovate and smooth; posterior subrostrated and_ transversely
striated; beaks approximate, margin quite smooth.

Longest diameter, \ inch.

Locality. Cor. Crag, Sutton and Ramsholt.

This shell is abundant in the Coralline Crag at Sutton, but from its great fragility
specimens of the above dimensions are very rarely obtained, and if it be the same as
the Belgian fossil, which I presume is the case, M. Nyst speaks of it as being by no
means rare in the Campinian Beds.

The striz or transverse ridges upon our shell are rounded and obtuse, not sharp
or imbricated; they cover the posterior half of the exterior, extending from a little
beyond the centre or umbo to the extremity, but often become irregular and obsolete
upon the posterior slope, and the shell is there depressed and subsinuated with a very
slightly recurved and somewhat pointed termination at the extremity of the dorsal
edge. From the extreme thinness of the shell the transverse edges are often visible
in the interior; a long line of sharp angularly formed and prominent teeth occupy
the hinge area, amounting in large specimens to as many as five and twenty on the
anterior, with twenty or more on the opposite side, while in young ones they are not
above half that number: they are separated by a rather large and obtusely angular

92 MOLLUSCA FROM THE CRAG.

ligamental pit, somewhat contracted in the middle; a large lanceolate-formed and well
defined lunule and corslet may be seen on both sides of the umbo, but the muscle
marks within are very slightly impressed and are indistinct, with doubtful traces of a
deeply sinuated form in the one by the mantle.

I am not at all acquainted with the range of this species; but it does not appear
to have a specific relationship with MVucula levis, Say, with which M. Nyst has con-
sidered his shell identical, and to which he would also unite JV. imatula, a very
different species. It resembles in outline JV. sapotilla, Gould, but seems to differ speci-
fically from it in the conspicuous transverse ridges, as well as in having a greater
number of teeth, depending upon the figure and description of that very accurate
observer, Dr. Gould, who would undoubtedly have pointed out the exterior ornament
had it possessed any.

4. Lepa caupata, Donovan. Tab. X, fig. 12, a—d.
Arca caupaTa. Don. Brit. Shells, vol. iii, pl. 78, 1802.
— minuta. Mont. Test. Brit., p. 140, 1803, not Broc.
_- _— Turt. Conch. Dict., p. 11, fig. 98, 1819.
— — W. Wood. Ind. Test., p. 47, pl. 10, fig. 44, 1828.
Nucuta minuta. Turt. Brit. Biv., p. 178, 1822.
me — Brown. Illust. Conch. Gr. Brit., pl. 25, fig. 18, 1827.
— — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 298, pl. 14, fig. 6,
1840.
— — Gould. Invert. Massach., p. 101, 1841.
— rostrata. G. Sowerby. Genera No. 17, fig. 5.
— a Mac Gill. Moll. Aberd., p. 245, 1843.
Lepa minuta. Mller. Ind. Moll. Groenl., p. 17, 1842.
— — King. Ann. Nat. Hist., vol. xviii, p. 240.
_- — Forbes. Mem. Geol. Surv., vol. i, p. 419, 1846.
— caupaTa. Lovén. Ind. Moll. Scand., p. 34, 1846.
== a Alder, Cat. Moll. North. and Durh., p. 79, 1848.
~— — Forb, and Hanl. Hist. Brit. Moll., vol. ii, p. 226, pl. 47, figs. 12, 13, and
pl. P, fig. 2, 1849.

Spec. Char. Testa transversd, elongato-ovatd, vel ficiformi, conveaiusculd, tenui ; con-
centricée striatd, antice breviori, rotundatd ; posticé longiori attenuatd, angulatd, et sub-
rostrata, margine integro.

Shell transverse, elongato-ovate or fig-shaped, slightly convex, thin; covered
with transverse or concentric striz; anterior side the shorter, rounded, posterior
attenuated, angulated, and subrostrated, margin smooth.

Longitudinal diameter, 3 an inch nearly.

Locality. Red Crag, Sutton.

Mam. Crag, Bridlington.
Clyde Beds. Recent, Britain, Scandinavian Seas, and North America.

BIVALVIA. 93

I have seen but one specimen of this species from the Red Crag, which was found
by myself nearly twenty years since, and I presume it, therefore, to be rare in that
Deposit ; one specimen also from the Cabinet of Mr. Leckenby, found at Bridlington,
appears to belong to the same species, and they are both assigned to the recent
British one, and to the more ventricose or less transverse variety: specimens of the
recent shell, corresponding in every respect with our Crag fossil, have been obtained

by myself on the shore at low water on the Coast of Suffolk, and I have no hesitation
in pronouncing upon their identity.

5. LepA PERNULA, Miller. Tab. X. fig. 18, a—e.

Arca PERNULA. Mill. Besch. Berl. Naturf. Fr., iv, 57, 1779, fide Lovén.
— Martini. Chem. Conch. Cab., t. vii, t. 206, fig. 550, 1784.
— rostrata. Gmel., fide Lovén.
— _ W. Wood. Ind. Test., p. 47, pl. 10, fig. 43, 1825.
— FLuviaTitis. Schrot. Fluse., p. 187, pl. 9, fig. 2, fide Desh.
NucuLa FLUVIATILIS. G. Sowerby, Genera No. 17, fig. 3.
— ostonea. Brown. Ilust. Conch. Gr. Brit., pl. 25, fig. 17, 1827.
— rostrata. G. Sowerby. Conch. Illust., fig. 12.
— — Desh. 2d ed. Lam., t. vi, p. 504, 1835.
— Jacxsont? Gould. Inv. Massach., p. 102, fig. 65, 1841.
_ — Dekay. Nat. Hist. New York Zool., p. 181, pl. 12, fig. 213, 1843.
— TENUISULCATA. Couth. Bost. Journ. Nat. Hist., vol. ii, p. 64, pl. 3, fig. 8, 1839.
Lepa rostrata. Forbes. Mem. Geol. Sury., p. 420, 1846.

—_ — Schum. Essai, &c., p. 173, pl. 19, fig. 4, a—4, 1817.
— PERNULA. Lovén. Ind. Moll. Scand., p. 34, 1846.

Spec. Char. Testé transversdé elongatd, anticé rotundatd, postice duplo longiori, in
rostrum obtusum attenuatd, concentricé striata.
Shell transverse, elongate, anterior side rounded, posterior twice the length and
attenuated, terminating in an obtuse beak, concentrically striated.
Longest diameter, Zths of an inch.
Locality. Mam. Crag, Bridlington.
Clyde Beds.

One specimen (fig. 13, ¢) belonging to Mr. Bean, found at Bridlington, and
obligingly lent to me by that gentleman for the purpose of description, appears to
be somewhat different from the preceding, it corresponds with the recent form found
in the Boreal Seas of Europe, and which is most probably also a native of the
Northern Coast of America. Our fossil is not in good condition, being compressed
and slightly broken, and its natural form in consequence somewhat distorted, but it is
sufficiently perfect to permit of a presumed evidence of identity with the recent species.
It is more inequilateral than the preceding species, larger, and with finer concentric
strie, corresponding with the figure and description of JV. tenwisulcata, Couthouy, and
of which, probably, JV. /acksonz, Gould, is only a variety. Fig. 13, a, 6, is the repre-
sentation of a specimen from the Clyde Beds, given to me by Jas. Smith, Esq., of

94 MOLLUSCA FROM THE CRAG.

Jordan Hall; all the specimens I have seen from these Deposits are small, scarcely
exceeding half an inch in length, while the one from Bridlington has nearly twice
that diameter.

This appears to differ but very slightly from the more elongated variety of
L. caudata, considered a different species by our British Conchologists, as well as by
Dr. Lovén, the principal difference is in the striae, which in this shell is finer or
more numerous.

6. Lepa TRuNCATA, Brown. Tab. X, fig. 14, a—é.
Nucuta TruNcATA. Brown. Illust. Conch. Gr. Brit., pl. 25, fig. 19, 1827.
a — Smith. Mem. Wern. Soc., vol. viii, p. 42, 1838.

Spec. Char. Testé transversd, ovatd ; concentricé striata, tumidd, subequilaterd ;
antice rotundatd, postice truncatéd vel subsinuatd; umbonibus prominulis ; margine
entegerrimo.

Shell transverse, ovate, subequilateral, tumid, concentrically striated; anterior
side rounded, posterior truncate or subsinuated ; umbones slightly prominent ; margin
smooth.

Length, Zths of an inch nearly. Hezght, $ an inch.

Locahiy. (-————. 8

This shell has been rejected by the authors of the ‘ Hist. of British Mollusca’ as
an existing British species, and although not found in any of our Crag Deposits,
belongs undoubtedly to the Upper Tertiaries of England. It is an animal still living
in the Arctic Seas, but is no longer an inhabitant of our own.

The specimen figured was obtained by Robert M‘Andrew, Esq., who has
obligingly permitted me the use of it for the purpose of description: it was, he says,
in company with other, supposed extinct, species as Pecten Islandicus, &c., and
dredged from the depth of 40 to 60 fathoms, off the North Western Coast of the Isle of
Skye. It is ornamented with close-set stric, that appear independent of lines of growth,
as they occasionally bifurcate, and are not, therefore, quite parallel to the margin; its
most peculiar character is on the posterior side, where there is a somewhat angular
ridge or keel from the umbo to the projecting beak-like termination, forming above
a large and elongate lunule-like space between it and the margin of the shell; below
is another obtuse ridge extending from the umbo to the posterior part of the ventral
margin, and between this and the pointed termination, the shell is flattened or slightly
contracted at the margin, from which it is presumed it received its name: the shell is
tumid, the umbones somewhat curving over, so that the ligamental area projects
inwards; there are from 12 to 18 teeth on each side, while the smus in the mantle is
not very deep: the specimen is a full grown or aged individual, as the interior is
irregularly thickened, and more especially rugose between the margin of the shell
and the line of attachment by the mantle.

BIVALVIA. 95

7. Lepa pyemma, Minster. Tab. X, fig. 11, a—d.

Nucuta pyem#a. Munst. Apud. Goldf. Pet. Germ., vol. ii, p. 157, t. 125, fig. 17.

_ — S. Wood. Mag. Nat. Hist., New Series, vol. iv, p. 298, pl. 14, fig. 7,
1840.

— — Phil. En. Moll. Sic., vol. ii, p. 46, 1844.
— — Middendorff. Mem. de Y Acad. Imp. de St. Petersb., p. 544, 1849.
— arBsosa. Smith. Mem. Wern. Soc., vol. viii, pl. 2, fig. 10, 1838.
— corBuLorpEs. Id. in addendum.
— meNnuis. Phil. En. Moll. Sic., vol. i, p. 65, pl. 5, fig. 9, 1836.
_ — Jeffreys. Aun. Nat. Hist., vol. xix, p. 313.
— tuenticuLta. Méll. Ind. Moll. Groenl., p. 17, 1842.
— Purtipprana. Myst. Coq. Foss. de Belg., p. 224, pl. 17, fig. 5, a—e, 1844.

Lupa prema. Forbes. Mem. Geol. Surv., vol. i, p. 419, 1846.

— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 230, pl. 47, fig. 10, and

pl. P, fig. 3, 1849.
Yotp1a pyeM#A. Lovén. Ind. Moll. Scand., p. 35, 1846.

Spec. Char. Testé minutd, ovato-trigonuld, subequilatera ; tumidd, levigatdé, politd,
clausé ; antice ovato-rotundatd, postice subrostraté ; lunuld indistinctd ; margine inte-
gerrimo.

Shell small, triangularly ovate, subequilateral, gibbous, smooth, glossy, and closed ;
anterior side roundedly ovate; posterior subrostrated, without a distinct lunule;
margin very smooth.

Longitudinal diameter, +th of an inch.

Locality. Cor. Crag, Sutton, Ramsholt, Gedgrave.

Clyde Beds. Recent, Mediterranean? Britain, Scandinavia.

This species is found in several localities of the Coralline Crag, and very abundantly
at Sutton. It may be further described as having a very broad hinge line furnished
with 8 to 12 teeth on each side of the umbo, they are angular, large, and promi-
nent in the centre of the area and towards the sides, with large interspaces for
the interlocking of the teeth of the opposite valve, by which the two valves are
often found in conjunction. The shell is very tumid, moderately thick and strong,
and perfectly closed all round, it has a somewhat prominent umbo, and is without any
defined lunule or corselet; the posterior side is generally though not always the
larger, and its termination rather acuminated and a little curved upwards: the
fossette for the ligament is very small, and the muscle marks not in general deeply
impressed or well defined; that by the mantle has a small sinus. The shell is glossy
both within and without, and slightly nacreous. My Crag specimens are small, not
exceeding the sixth of an inch in the transverse or greatest diameter; but a few
specimens from the Clyde Beds, obligingly given to me by James Smith, Esq., of
Jordan Hall, appear to have attained larger dimensions, and are rather less equilateral.

This shell is given by Philippi, on the authority of Scacchi, as a species living
in the Mediterranean, and it is also found fossil in the Upper Tertiaries of that part
of the world. Bis:

96 MOLLUSCA FROM THE CRAG.

The living animal has recently been obtained by Mr. M‘Andrew, from the depth
of nearly 50 fathoms, on a muddy bottom, in the Sound of Skye; and it is quoted by
Lovén as an existing species on the Coast of Finmark, while Moller gives it from the
Greenland Seas.

8. Lepa THRACcI#FoRMIS, Storer. Tab. X, fig. 15.
Nucuta Turacir#Formis. Stor. Bost. Journ. Nat. Hist., vol. ii, p. 122, 1838.
— — Gould. Invert. Massach., p. 97. fig. 66, 1841.
— — Dekay. Nat. Hist. New York (Zoology), p. 178, pl. 12, fig. 217,
a—b, 1843.

Spec. Char. “ Testa ovato-oblongd, transversd, nigra, crassa ; anticé rotundatd, postice
truncata et compressa, umbonibus prominentibus ; cardine foved magna.” (Storer.)

“ Shell ovato-oblong, transverse, black, and thick; anterior side rounded, posterior
truncated and compressed, beaks prominent, with a large ligamental pit.”

The specimen figured, was obtained by R. M‘Andrew, Esq., a gentleman to
whom science is so largely indebted for a more correct knowledge of our native
Marine Fauna. This novelty is the result of one of his very recent explorations in
the Sound of Skye, and was dredged, he tells me, at the depth of about 50 fathoms,
and found in association with Leda truncata, Pecten Islandica, &c., species supposed to
have become extinct in our own Seas, though still existing in some other regions of
the Northern Hemisphere: the specimen (although but a fragment, is a considerable
portion of the shell), was consigned to Professor E. Forbes, who is also of opinion
that it is identical with Leda Thracieformis, and I am much indebted to those two
gentlemen for the privilege of being the first to make it known as having once been an
inhabitant of our own Seas; and although it be another, to which as a describer of
the Crag species I may not strictly have a claim, it belongs at least to the bygone
times, and comes into the province of the Paleontologist.

What remains of the specimen seems to justify its being considered as belonging
to the species to which it is here assigned, although the most characteristic portion of
the shell is destroyed; I have, therefore, copied the specific character from the
original describer: it differs from Z. truncata in being somewhat thinner and more
compressed, but there is scarcely enough of the shell remaining to show satisfactorily
the peculiar ridge on the posterior side sloping from the umbo to the extremity of
the ventral margin: it is ornamented with concentric striae, like Z. truncata, and they
are slightly wavy in their direction.

The specimens of this species hitherto recorded as having been found in the recent
state were from the stomachs of the Cod and Sand-dab, and these fishes were taken
at the depth of 30 fathoms and upwards.

The outline tracing is copied from the figure of the recent shell in Dr. Gould’s
“Invertebrata of Massachusets.’

BIVALVIA. 97

+

Unio, Retzius, 1788.
Mya (sp.). Zinn., 1747. Syntoxta. Rafinesque, 1820.
TrrauptRa. Klein, 1753.* AtasmoponTa. Say, 1820.
Limn#a and LimnopeERMA (sp.). Poli., 1791. Mysca. Turton, 1822.
Cristaria. Schum., 1817. DreLopon. Spix, 1827.
PaxYoDON. Id. a TETRAPLODON. Id. ,,
PRIsODON. Id. r Lasmicona? Rafin., 1831.
MarGaritana. Id, 45 Lasmonos? Id. A
AMBLEMA. Rafinesque, 1819. MonoconpyL#a. D’Oré., 1835.
ELLIPTio. Td. _ ABGLIA. Swainson, 1840.
Evurynia. Id. Ss Cantuyria. Id. 5
OBOVARIA. Id. 33 CALCEOLA. Id. (not Lam.), 1840.
PLAGIOLA. Id. 5 ComPLANARIA. Id. 1840.
PLevropema. Id. os CUNICULA. Id. 5
PROPTERA. Td. Fe HeEmIopon. Td. aS
TRUNCILLA. Id. 5 Hyripenita. Id. a
AXIMEDIA. Id. 1820. TRIDEA. Id. 5
DIPLASMA. Id. 33 Ligumtia. Id. FP
ELLIPSARIA. Id. 5 LYMNADEA. Id. 3
LamMpPsILis. Id. e Mrcapomus. Id. 5
LEPTODEA. Id. Fe Nata. Id. “3
METAPTERA. Id. be NAIDEA. Id. $3
OBLIQUARIA. Id. a PovraMIDA. Id. Pa
QUADRULA. Td. ne THELIDERMA. Id. ee
RoTuNDARIA. eh 53 UNIopsis. Id. 3
SCALENARIA. Td. Bs Luticoua. Goldfuss, 1846.

Generic Character. Shell equivalve, inequilateral, generally thick and externally
smooth, occasionally ornamented with nodules or spines. In the recent state covered
with an epidermis, often wanting at the umbones, where the shell is sometimes much
eroded. Hinge, with two cardinal teeth in the left valve, and one, sometimes two, in
the right, an elongated lateral tooth on the posterior side. Impressions by the
adductor muscles large and deep, that by the mantle without a sinus. Ligament
external. Shell nacreous.

Animal of the form of the shell, its mantle open in front, with simple edges or
slightly fringed; siphonal tubes short, plain or fringed, sometimes scarcely defined ;
foot large, compressed.

This is pre-eminently a fresh-water genus, and although found living in the rivers
of Europe, Asia, and Africa, appears to be only fully developed in the lakes and
rivers of North America, more than 200 species have been named and described from
that part of the world. :

* In compliance with the recommendation of the Committee appointed by the British Association for
the Advancement of Science, 1842, ‘‘to consider the rules by which the Nomenclature of Zoology may be
established on a uniform and permanent basis,”—the 12th edition of Linneeus’s ‘Systema Nature,’ 1767,
is made the starting point from which the dates of priority have been adopted.

13

98 MOLLUSCA FROM THE CRAG.
.
The difference between this genus and that of Azodonta is in the absence of teeth

in the latter, as the name implies; but the modification of the hinge as well as the
outward form of the shell in the whole group is so exceedingly variable, some being
perfectly orbicular, while others are elongated and cylindrical, as to have caused it to
be divided into numerous Genera, but these divisions appear to be founded upon
characters alike unstable and insignificant.

As fossil, this genus is said to date its existence from the Coal Measures; it is
found in the Wealden, and in the Fresh-water Deposits of the Older as well as the
Newer Tertiaries, and wherever met with, the species are seldom numerous, but the
individuals are usually very abundant.

1. UN1Io LiTTORALIS, Lamarck. Tab. XI, fig. 12, a—é.
Unto Lirroratis. Lam. Syst. des An. sans Vert., p. 114, 1801.
— — Id. Hist. des An. Sans. Vert., t. vi, p. 66, 1815.
— — Drap. Hist. Nat. des Moll. Ter. et Fluv. de France, p. 133, No. 3,
pl. 10, fig. 20, 1805.
— — Brard. Hist. Coq. des Env. de Par., p. 222, pl. 8, fig. 6, 1815.
— — Pfeiffer. Land and Sussw. Moll., p. 117, pl. 5, fig. 12, 1821.
_ — Phil. En. Moll. Sic., vol. i, p. 66, and vol. ui, p. 48.
= — Mag. Nat. Hist., New Ser., vol. ii, p. 548, fig. 27, 1838.
ee: Lyell, Elem. of Geol., 2d ed., vol. i, p. 62, fig. 29, 1841.
—_ — G. B. Sow., Jr. Conch. Man., fig. 145, 1842.
— _ Rossmas. Icon. der Land and Sussw. Moll., No. xi, p. 14, t. ly, figs. 473,
744, and No. xii, p. 27, t. lvi, figs. 752—754, 1844.
_— — Dupuy. Ess. sur les Coq. Viv. et Foss. Dep. du Gers., p. 86.
— PraneENsIs. Farines. } =
— SUBTETRAGONUS. Mich. J BPO agaeaiee'
— NANA. Desh. 2d ed. Lam, t. vi, p. 539, No. 17, 1835.
— antrauior. Sérickland. Silur. Syst., p. 555, 1839.
— incurvus, Lea. Obs. Gen. UNIO, vol. i, p. 107, pl. 13, fig. 27, 1832.
— GRanosus. Schum., fide Lea.
Mya rHomBorDpA. Schréter. Ausland. and Flussch., t. 2, figs. 2, 3, 1783.
Ency. Meth., pl. 248, fig. 2.

Spee. Char. Testé ovato-oblongd, crassa, valde inequilaterd, antice rotundatd, postice
subquadratd, compressiusculd ; umbonibus prominulis, flecuosis, undulatis ; dente antico
cardinis dextri crasso, triangulari.

Shell ovato-oblong, thick, very inequilateral; anterior side rounded, posterior
subquadrate, slightly compressed; umbones with undulating rugosities; anterior
cardinal tooth in the right valve thick and triangular.

Length, 25 inches. Height, 1% inch.

Locality. Cropthorn (Strickland), Clacton, Grays (Morris), Uford (A/orris).

Recent, France, Sicily.

Exceedingly abundant in the Fluviatile Deposit at Clacton.

BIVALVIA. 99

It may be further described as being furnished with two cardinal teeth in the left
valve, the anterior one is somewhat thin, sharp, and angular, sloping towards the muscle
mark on that side, the other one on the posterior side of the umbo is thick, strong, and
rugose, with a sharp, linear, lateral tooth, nearly parallel to the dorsal margin, or liga-
mental fulcrum: the right valve has one large cardinal tooth divided in the middle, this
fits into a depression in the left valve of a corresponding form, and parallel to the margin
is an elongated, sharp, and elevated, lateral tooth ; the muscle marks are deeply im-
pressed, more especially the anterior one, this is rugose and subquadrangular, and is
bipartite or has a smaller one adjoining, more within the shell; the posterior one,
placed at the extreme edge of the ligament, is slightly ovate, with the mantle mark
parallel to the margin of the shell, connecting the adductors ; the posterior is obtusely
angular, and the shell on that side is somewhat compressed or less tumid than at the
anterior: the surface of the shell is roughened by irregular and. prominent lines
of growth; on many of the individuals there are the remains of the epidermis, and
in most instances the specimens have the ligament entire, with the valves in their
natural position.

Several valves in my Cabinet have specimens of Balanus adhering to them,
showing the proximity of the Sea at one time to this Deposit, or perhaps the re-
occupation by salt-water of the locality once filled with fresh-water and its inhabitants.

This species has now an extensive Geographical range, being found in the North
of France, and in the fresh-waters of the Island of Sicily; and Lea, in his ‘ Observations
on the Genus Unio,’ vol. i, p. 201, says “'the shell found in the Euphrates, near
Bagdad, is only a variety of this species,” and he records it also as the opinion of the
Baron de Ferussac. I have never seen this shell.

2. Unio Tumipus, Retzius. Tab. XI, fig. 13.
Unio tumipus. Retz. Nova. Gen. Test., p. 17, 1788.
— — Pfeiff. Land und Sussw. Moll., pt. ii, p. 34, pl. 7, figs. 2, 3, and pl. 8,
figs: 13.2%
— — Rossm. Icon. Land und Sussw. Moll., pt. i, p. 117, pl. 8, fig. 70;
pt. ili, p. 27, pl. 14, figs. 262—4; pl. 40, fig. 542; pl. 60,
figs. 772-—778.
— _ Gray. Man. Land and F. W. Shells, p. 297, pl. 2, fig. 13, 1844.
— _ Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 140, pl. 40, fig. 1, 1849.
Mya ovauis. Mont. Test. Brit., p. 34, 1803.
— pepressa. Don. Brit. Shells, vol. ii, t. 101, 1802.
— ovata. Don. Brit. Shells, vol. iv, t. 122, 1803.
Mysca ovata. Turt. Brit. Biv., p. 246, 1822.
— —— Swains. Malac., p. 277, fig. 56, 1840.
— souipa. Turt. Brit. Biv., p. 246, pl. 16, fig. 2, 1822.
Unio prctorum. Brown. Illust. Brit. Conch., pl. 26, fig. 2, 1827.
— ovauis. Sowerby. Genera of Shells, No. 16, Unto, fig. 1.
— — Brown. MUlust. Brit. Conch., 2d ed., pl. 31, figs. 1—4.
— rostrata? Desh. 2d ed. Lam., p. 540, t. vi, 1835.

100 MOLLUSCA FROM THE CRAG.

Spec. Char. Testd ovati, transversd, elongata, crassé, valdé inequilaterd ; anticé
rotundatd, posticé producti, cuneatd, subrostratd ; umbonibus rugosis.

Shell ovate, transversely elongate, thick, very inequilateral ; anterior side rounded,
posterior produced, somewhat pointed, and obtusely angulated or wedge-shaped ;
umbones rugose.

Length, 33 inches. .

Locality. Stutton, Grays. Recent, Britain, France, and Germany.

This species is very abundant at Grays, where specimens have been obtained in
great perfection, and although by no means rare at Stutton, they are in a very
decorticated condition. Both these localities present us with forms deviating con-
siderably from what are generally met with in the living state, more especially those
from the latter locality, where they attain a magnitude of nearly four inches in length,
and appear to have a greater proportion of the shell on the anterior side of the umbo,
while in those from Grays, which are smaller, that side is shorter and proportionally
broader than in the living specimens ; in the Grays fossil the posterior side is obtusely
pointed, and the whole shell is more angular, while the Stutton specimens are rather
less so than the general or common form of the recent shell; as these extremes of
variation can readily be connected through the living species, it is presumed that the
differences are wholly insufficient for specific separation, and I have no hesitation in
assigning the fossils of both localities as identities of the existing British species; the
dental characters are also similar, the anterior tooth of the right valve being coarsely
crenated on the upper or dorsal side, and somewhat compressed; the elongated
lamina on the posterior side is linear, sharp, and nearly smooth.

It was at first thought, that as the Land and Fresh-water shells found in the
newer Tertiaries of this country are a// assumed to be the Homogenitors of exist-
ing animals, a name alone with reference to a work in which they have been
described would have been sufficient for Geological purposes ; but upon more minute
examination many of them have been found to present characters deviating in so great
a degree, that their identity has by some Conchologists been called in question; it is
therefore now considered desirable that a figure and description of a part of them at
least should be given, more especially as they have never yet appeared in any publi-
cation as British Fossils.

3. UNIo picroruM. Linnaeus.
Mya PictoruM. Linn. Syst. Nat., ed. 12, No. 28, p. 1112, 1767.
as — Poli. Test. Sicil., vol. 1, p. 2, t. 9, figs. 6, 7, 1791.
Unto pictorum. Drap. Moll. Tert. et Fluv. de Fr., pl. 11, fig. 4, 1805.
— = Gray. Man. Land and F.-W. Shells, p. 295, pl. 2, fig. 11, 1844.
ae — Rossm. Icon. Land und Sussw. Moll., figs. 71, 196; pl. 29, fig. 409 ;
pl. 58, figs. 762—766, 1844.
— a Forb. and Hanl. Hist. Brit. Shells., vol. ii, p. 142, pl. 39, fig. 1, and
pl. Q, fig. 2 (Animal), 1849.

BIVALVIA. 101

Mysca picrorum. Turt. Brit. Biv., p. 245, 1822.
— Desuayest. Brown. Illust. Brit. Conch., p. 81, pl. 32, figs. 1—4.
— — Rossm. Icon. Land und Sussw. Moll., p. 23, pl. 13, fig. 197.
— .Lonerrostris. Ziegl. in Rossm. Iconog., pt. 3, p. 26, pl. 14, fig. 200, and pt. 12,
pl. 54, fig. 38.
Ency. Meth., t. 248, fig. 4.

Spec. Char. Testé transversé, elongata, subovatd, inequilaterdé, anticé rotundata,
posticée, angulatd, vie rostrata ; margine dorsali et ventrali subrectd.

Shell transversely ovate, elongate, inequilateral ; anterior side rounded, posterior
angulated, scarcely rostrated; dorsal and ventral margins nearly straight.

Length, 2 wches.

Locality. Grays, Cropthorn. Recent, Britain, France.

This shell appears very rare as a British fossil; one specimen in the cabinet of
Mr. Pickering is of a form that may be determined without much hesitation as belong-
ing to this species, and resembles rather the thinner variety of the recent shell. The
principal or perhaps only difference observable between this and the preceding species
in the fossil state, is a more elongated dorsal area, less sloping on the posterior side,
so that the ventral margin is more parallel with the upper edge than in U. tumidus.
A specimen in the British Museum, from the same locality, seems to possess the like
determinable characters, and one in the Museum of the Geological Society, presented
by Mr. Strickland as from Cropthorn appears to be of this species. These specimens
are all that I have seen, they mostly resemble fig. 766, Rossmasler.

Anoponta, Cuvier, 1798.

Muscutus (sp.). Lister. Cristarta. Schum., 1817.
Mytiuus (sp.). Linn. Srropuitus. Rafinesque, 1820.
Limn®a and LimnmoperRMa (sp.). Poli, LASTENA. Id.

1791. Sympuynota (sp.). Lea., 1832.
AnopontitTgEs. Brug., 1799. OpaTeLIa. Rafinesque, 1832.
Drresas. Leach, 1814. LAMPROSCAPHA. Swains., 1840.
Appius. Id. MSS., fide Gray, HEMIopon. Id.
Anopon. Oken., 1815. PATULARIA. Id.

Generic Character. Shell equivalve, inequilateral, ovate, transverse, usually thin,
more or less eared, and closed; smooth, and in the recent state covered with an
epidermis generally eroded at the umbones. Hinge linear, edentulous, or with one
elongated lamina on the posterior side. Ligament external. Impression of the mantle
without a sinus.

The animal of this genus closely resembles that of the preceding one, being furnished
with a large fleshy, compressed foot, and the hinder part of the mantle is ornamented
with short and pointed tentacles; anal opening is large, and the margin plain.

102 MOLLUSCA FROM THE CRAG.

These animals are bisexual, and the young shell is completely formed before
exclusion, although differing then materially in shape from that of its parent. _Their
power of multiplication is said to be enormous. Mr. Lea states that he counted not
less than six hundred thousand young in an adult specimen.

The shells of this genus are also exceedingly variable, more especially in the out-
ward form; some species have the hinge area largely elevated into the form of a wing,
and in consequence of these variations, as well as from differences in size of dental
characters, they have also been separated into several genera.

It appears to be a modern genus, and only yet known in the fossil state from the
newer Tertiaries.

]. ANODONTA CYGNEA, Linneus. Tab. XI, fig. 11.

Myvtitus cyengus. Linn. Syst. Nat., ed. 12, No. 257, 1158, 1767.

— -- Mat. and Rack. Linn. Trans., vol. viii, pl. 3A, fig. 2, 1807.

— — Poli. Test. Sicil., vol. ii, p. 212, pl. 33, fig. 2, 1795.

— — Sheppard. Trans. Linn. Soc., vol. xiii, p. 84, pl. 5, fig. 3, 1822.

— anatinus. Linn. Syst. Nat., ed. 12, p. 1158.

= — Poli. Test. Sicil., vol. ii, p. 213, pl. 33, fig. 1, 1795.

— AVONENSIS. Mont. Test. Brit., p. 172, 1803.

— — Mat. and Rack. Linn. Trans., vol. viii, p. 250, pl. 3.

— macuLa. Sheppard. Linn. Trans., vol. xiii, p. 88, pl. 5, fig. 6, 1822.

STAGNALIS. Sowerby’s Brit. Miscellany, pl. 16.

— — Brown. Illust. Brit. Conch., pl. 27, fig. 2, 1827.

— oventatus. Turt. Conch. Dict., p. 115, 1819.

— uncrassatus. Sheppard. Linn. Trans., vol. xiii, p. 85. pl. 5, fig. 4.
ANODONTA CYGNEA. Pfeiff. Land und Sussw. Moll., p. 111, t. vi, fig. 4, 1821.

— ANATINA, Id. - - - ef hpi lL 12, ti, Mies asak ass

— INTERMEDIA. Id. - - - =p, 113, 6. va, dips os 3 is

—_ venTRIcOSA. Kick. Moll. Brab. Aust., p. 80.

— PISCINALIS. Nils. Moll. Succ. Ter. et Fluv., p. 116, fide Ford. and Hanl.

— cYGNEA. Rossm. Icon. Land and Sussw. Moll., pp. 1, 111, t. 3, fig. 67, 1835.
ANopon PaLuposa. Turt. Brit. Biv., p. 240, pl. 15, fig. 6, 1822.
Sympuynota cyenna. Lea. Obs. on the Gen. Unto, vol. i, p. 70, 1832.

Spec. Char. Testa oblongo-ovata, sepe compressa, tenui, interdum tumida et incrassata ;
anticé rotundatd, postice productd, et angulatad ; natibus depressiusculis, rugosis.

Shell oblongo-ovate, generally compressed and thin, sometimes tumid or inflated,
occasionally thick ; anterior side rounded, posterior produced, and angulated ; umbones
rather flat, with undulating rugosities.

Length, 33 inches. Height, 2 inches.

Locality. Stutton, Clacton, Grays (Pickering), Cropthorn, and Bacton (Morris).

Recent, Britain, and North of Europe.

This species is abundant in individuals both at Stutton and Clacton, the two
localities of Fresh-water Deposits that I am best acquainted with, although from
their great fragility specimens are very difficult to obtain in any degree of

BIVALVIA. 103

perfection. In all probability it was equally variable in the earlier periods of its
existence, as it is at the present day. The few specimens that I possess present
considerable differences in outward character, from which, therefore, it is not unfair
to infer, that amongst a greater number, and from different localities, we should, as in
the living shell, which varies under different external conditions, also have a great
variety in the fossil state.

The specimens from Stutton (generally in a decorticated condition) are very in-
equilateral, the anterior side being particularly short in proportion to the other, and
the shell is rather less in length comparatively, but it is almost impossible to obtain a
specimen at that locality without some slight degree of distortion, and its true characters
are therefore difficult to determine; but there is no doubt it is the homogenitor of our
old acquaintance, which in the living condition puts on sucha variety of shapes. The
one from Clacton is more elongate, and corresponds with a variety abundant in the
Thames above Maidenhead, in Berkshire. Mr. J. E. Gray (Manual of Land and
Fresh-water Shells of the British Islands) considers the many different forms found in
this country, and described under distinct specific names, to be only modifications of
the same species, and the authors of the ‘ History of British Mollusca’ are of the same
opinion; from what I have seen I fully acquiesce in their decision, and the fossil
specimens that have come under my observation may be arranged in the same
category.

As the geographical range of this species extends over the greater part of Europe,
we may naturally expect to find it in the fossil state.

CyRENA, Lamarck. 1818.

VeENus (sp.). Chem.

TELLINA (sp.). Gmelin.

Cycuas (sp.). Lam., 1799, 1801.
CorspicuLta. Megerle, 1811.
CyanocycLas. Ferussac, 1818.
GeLotna. Gray, 1844.
Wenornral sid: 4,

Generic Character. Shell equivalve, roundly trigonal or subovate, generally
tumid or inflated, more or less inequilateral, thick and strong. Hinge with three
cardinal teeth, and a large extended lateral tooth on each side, serrated or striated in
some species: in the recent state covered with an epidermis: ligament external:
impression of the mantle without a sinus.

The animals constituting this genus are in a recent state inhabitants of pure
fresh-water, and are only known in tropical or sub-tropical rivers, where the climate is
particularly mild. They are described by Malacologists as not differing essentially

104 MOLLUSCA FROM THE CRAG.

from the fresh-water genus Cyc/as, excepting in their shelly covering, which in this shell
is thick and opaque, while in Cyclas it is thin and corneous or semitransparent. Lamarck
placed them in his Family Conche fluviatiles, in consequence of a resemblance to the
animals of the Veneridz, and from possessing the lobes of the mantle prolonged into
siphonal tubes, distinct and separated down to their bases.

Although in the recent state, this is a genus of pure fresh-water origin ; specimens
have been found in the Estuary Deposit of the Norwich or Mammaliferous Crag almost
too numerous to be considered as entirely of accidental introduction.

1. CYRENA CONSOBRINA, Caillaud. Tab. XI, fig. 15, a—e.
CyrENA consoBRINA. Cail. Voy. en Egypt, t. 2, pl. 61, figs. 10, 11, 1823.
— — Desc. de l Egypt Hist. Nat., t. 22, p. 193, pl. 7, fig. 7, 1, 2,3.
— mrRiconuLa. S. Wood. Mag. Nat. Hist., vol, vii, p. 275, fig. 45, a, 6, c, 1834.
— — Lyell, Elem. Geol., 2d ed., vol. i, p. 61, fig. 26, 1841.
— Gemmetiari. Phil. En. Moll. Sic., vol. i, p. 39, t. 4, fig. 3, 1836.
— — UPI - - vol. u, p. 31, 1844.
— Dvcuasrerii. Nyst. Bull. de la Soc. de ’Acad. Roy. de Brux., p. 113, pl. 1,
figs. 1—4, 1838.

Spec. Char. Testé rotundato-trigonuld, subequilaterd, tumidd, crassa ; lineis elevats,
concentricis, levibus, distantibus ; cardine tridentato, divergens, inter se insertis ; dentibus
lateralibus longissimis, perpendiculariter striatis.

Shell roundly trigonal, subequilateral, tumid, and thick; externally ornamented
with smooth, concentric, sharp, and distant ridges ; hinge with three cardinal diverging
teeth in each valve, lateral teeth elongated and perpendicularly striated.

Locality. Mam. Crag, Bramerton, Wangford, and Bulcham (Alexander).

Stutton and Grays. Recent, River Nile.

This species is exceedingly abundant in the purely Fresh-water Deposit at Stutton,
where the valves are commonly united, as they are in general with fresh-water species,
individual specimens may be obtained by hundreds. When the shell was first
described and figured in the ‘ Mag. Nat. Hist.,’ as referred to above, it was imagined to
be specifically distinct in consequence of the posterior side being somewhat angulated,
in which character it differs from the general form of the recent species, now con-
sidered as identical; but among a large series of the British fossils this character
disappears, and as a distinguishing mark cannot be faithfully relied upon, as the
specimens from Grays do not possess it, but have both sides more rounded, and
correspond in form precisely with the Nile shell; there is every reason, therefore, to
believe its descendant to be now living in the rivers of Egypt, to which part of the
world it appears to have retired through the once existing fresh-waters of Sicily, for
I consider the shell figured by Philippi, as nothing more than a variety of this species,
although he has described it as having only two cardinal teeth in each valve, while
there are three perfectly distinct in our shell; the anterior one in the right valve and

BIVALVIA. 105

the posterior in the left being the smallest, these in imperfect specimens of the fossil
might have been overlooked. ;

The outline of our shell is roundly trigonal, the posterior side being rather more
angular and larger than the other, and the diameter is generally greater in a longi-
tudinal direction, but in others it is even higher than long; the right valve has one
central, triangular, sub-bifid, cardinal tooth immediately beneath the umbo, and
another on each side of it diverging at a very considerable angle; in the left valve, the
three cardinal teeth correspond in form with the interstices of the right valve, two large
elongated and elevated lateral teeth, occupy the whole of the dorsal portion of the shell
in the left valve, and these fit into depressions of the right one so as firmly to fix
the two pieces when they are closed, and on each of these lateral teeth, as also on
each side of the dental furrow in the right valve, are numerous fine strize perpendicular
to these lateral ridges, and on the inside of the callus or fulcrum for the support of
the ligament are the same markings; the muscular impressions are somewhat unequal
in size, the posterior one being the larger and of a subquadrate form, while the anterior
is more triangular, these are connected by the line of the mantle-mark which has an
incipient sinus or indentation close to the posterior adductor; these marks are seldom
deeply impressed and not always visible, but when seen, they do not extend beyond
the extreme verge of the lateral teeth. On the ouside, the shell is ornamented with
numerous, sharp, generally equidistant ridges, parallel to the margin, and in the
concave spaces between them may be seen the lines of growth; a faint line is visible
in perfect specimens curving from the umbo on each side, forming a sort of large
corselet and lunule, of an elongated ovate form, beyond which the ridges do not
extend, precisely similar to what is seen in the A‘gyptian shell: in most of the
specimens of the fossil, the outside is more or less decorticated, but there is very little
of erosion visible in any of my specimens at the umbones, nor is the ligament ever
preserved, but that is not very thick even in the recent state.

It has been thought necessary to be thus tediously particular in giving all the
minutiz of characters belonging to this species, in order to remove any doubt respect-
ing its identity with the well-known shell now inhabiting a part of the world where
climatal conditions are different from what it is supposed were those under which it
existed in this country.

A few specimens of this species have been obtained by Capt. Alexander and
myself from the Coralline Crag at Gedgrave, near the mouth of the Butley River, but
in association with some /elices and other land shells, all identical with existing
animals. At this locality, the Crag appears to have been denuded of its more Coralline
portion, and these shells are intermixed near the present surface with the remains
of the Marine Molluscs of the lower part of that Deposit.

Depending, therefore, upon this evidence alone, we can scarcely consider the
Geological Age of this species to date its existence so far back as the Period of the
Coralline Crag.

14

106 MOLLUSCA FROM THE CRAG.

Crcias.* Bruguiére, 1792.

Spoarium. Scopoli, 1777.
Nux. Humph., 1797.
Cornea. Megerle, 1811.
CorneocycLas. Ferus., 1818.

Generic Character. Shell equivalve, subequilateral, more or less tumid or inflated,
thin and closed, sometimes semipellucid, smooth or slightly marked by lines of
growth, and in the recent state covered with an epidermis. Hinge furnished with
one or two cardinal teeth, and distant lateral teeth on each side. Impressions of the
adductor muscles indistinct. Palleal impression with a small sinus. Ligament
external, slender.

Animal suborbicular, its mantle open in front, with plain or simple margins;
siphon produced and divided at the extremity into two distinct tubes, the edges plain
or without fringes: foot large, compressed, extensile, and more or less pointed.

Priority of name most properly belongs to Scopoli, but the small and corneous
shells here included are so universally known by the above designation, that I do
not feel disposed to make the alteration, more particularly as Spheriuvm has been
since adopted in another department of Natural History as a Generic Term. Animals
now determined to belong to three distinct Genera were included by Bruguicre, as
well as by Lamarck, under the name of Cyc/as, and the latter author subsequently
proposed to sever from them the thicker and more ponderous species, and unite them
into a genus by themselves, under the name of Cyrena.

The shells constituting this genus are for the most part very thin, and of a
corneous or semitransparent texture in the living state; their little inhabitants are
possessed of considerable powers of locomotion, and move about in the water with
facility by means of their large and flexible foot; they frequent pools, ditches, lakes,
and sluggish streams, and when still, are generally found buried in the sand or muddy
bottom of the water. They are viviparous or rather ovoviviparous, and the young are
not only perfectly formed before exclusion, but are sometimes of considerable magni-
tude, occupying a large portion of the parent shell to the manifest inconvenience of
the mother.

They are purely Fresh-water Molluscs, and the Formations in which they are
found fossil, are either of Fresh-water origin or of Estuaries in close proximity into
which they have been washed. Species have been figured and described as belonging
to this genus from the Wealden Formation ; an undoubted Cyclas was found by myself
in the Fresh-water Deposit at Hordwell, belonging to the Older Tertiaries.

* Etym. ku«Ads, circular.

BIVALVIA. 107

1. CycLtas rivicota, Leach. MSS.

TELLINA conNEA. Linn. Syst. Nat., ed. 12, No. 72, p. 1120 (part), 1767.
— — Var. 3. Mat. and Rack, Linn. Trans., vol. viii, p. 59.

CarpIuM corNEUM. Mont. Test. Brit., p. 86, 1803, Var.
— NuX. Da Costa. Brit. Conch., p. 189.

CycLas cornea. Drap. Moll. Terr. et Fluy. Fr., p. 128, t. 10, 4gs. 1—3.
_ — Brard. Coq. Ter. et Fluv. des Env. de Par., p. 219, t. 8, figs. 2, 3.
— Rivicona. “ Leach” in Lam. Hist. des An. s. Vert., t. v, p. 558, 1815.
— — Turt. Brit. Biv., p. 248, pl. 11, fig. 13, 1822.
— Pfeiff. Land und Sussw. Moll., p. 121, pl. 5, figs. 3—5, 1821.
== — Sowerby. Genera of Shells, No. 38, Cyctas.
= — G. Sow., Jr. Conch. Man., fig. 111, 1842.
=e a Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 111, pl. 37, figs. 1, 2.

Ency. Meth., pl. 302, fig. 5.

Spec. Char. Testé transversd, ovata, tumiduld, crassiusculd, subequilaterd, anticeé et
posticé convexd ; concentricé striata ; ligamento cardinali conspicuo.

Shell transversely ovate, somewhat tumid and strong, slightly inequilateral,
anterior and posterior sides rounded: finely striated concentrically ; cardinal area
conspicuous.

Length, \ inch. Height, 3ths.

Locality. Southend (Warburton), Faversham (Zimmer).

I have not myself met with this species as a fossil, but specimens in that state
have been obtained by Messrs. Warburton and Trimmer, from Faversham and
Southend. The specimens referred to are in the Museum of the Geological Society.

2. CycLas cornEA, Linnaeus. Tab. XI, fig. 2, a—é.

TeLuina cornea. Linn. Syst. Nat., ed. 12, No. 72, p. 1120, 1767.
— — Chem. Conch. Cab., t. vi, p. 136, t. 13, fig. 133, bad.
= — Penn. Brit. Zool., ed. 4, p. 89, pl. 49, fig. 36.
a — Donov. Brit. Shells, vol. iii, t. 96, 1802.
— Rivals. Mill. Verm. Hist., t. ii, p. 202.
— STAGNICOLA. Sheppard, Linn. Trans., vol. xiv, p. 150, 1825.

Carpium cornnum. Mont. Test. Brit., p. 86, 1803.

CycLas cornpa. Pfeif’. Deutsch. Land und Sussw. Moll., p. 120, t. v, figs. 1, 2, 1821.
— — Turt. Brit. Biv., p. 248, pl. 11, fig. 14, 1822.
== — Gray. Man. Land and F.-W. Shells, p. 280, pl. 1, fig. 2, 1840.
— — Jenyns. Trans. Camb. Philos. Soc., p. 295, 1831.
= — Phil. En. Moll. Sic., vol. ii, p. 30, 1844.
— — Forb. and Hanl. Hist. Brit. Moll., vol.u, p. 113, pl. 37, figs. 3—6, 1849.
— eivauis. Drap. Moll. Terr. et Fluv., p. 129, pl. 10, figs. 4, 5, 1805.
— — Brard. Coq. Terr. et Fluv. Env. de Paris, p. 222, pl. 8, figs. 4, 5, 1815.
— FLAVESCENS. Mace Gilliv. Moll. Aberd., p. 246, 1843, fide Ford. and Hanl.

Spec. Char. Testa transversd, ovata, inflata, tenui, et fragili, subinequilaterd ; postice
majiore, subquadratd, antice rotundatd, concentricé striata, margine ventrali leviter arcuata,
apicibus obtusis.

108 MOLLUSCA FROM THE CRAG.

Shell transverse, ovate, tumid, very thin and fragile, slightly inequilateral, posterior
side the larger, and subquadrangular; anterior rounded, very finely striated con-
centrically ; ventral margin lightly curved.

Length, 4 an inch. Height, 2ths of an inch.

Locality. Mam. Crag, Bulcham, Southwold.

Cropthorn, Grays, Clacton, Stutton, Faversham.
Recent, Britain, France, Sicily.

This species is abundant in the Fresh-water deposits of Clacton and Stutton. The
principal form is nearly ovate, and some have both sides equally rounded, but occa-
sionally the posterior is obtusely angulated, the line of hinge carrying the lateral tooth
rather further backwards than ordinary, giving it on that side a somewhat square
outline. The animal in the recent state has strong adductor muscles, but they have
made only a very indistinct impression upon the shell; the hinge is furnished with an
apparatus well adapted to assist the close security of the valves, the right one having
a sharp prominent arched or diverging tooth, immediately beneath the umbo, which
locks into or between two others of similar form in the left valve; the lateral teeth
are prominent and at unequal distances, that on the posterior side being considerably
the more distant; in the left valve there is one before and one behind the umbo, »
and in the right there are two on each side, between which the single one is inserted
when the valves are closed. Some specimens are quite smooth, while others are
distinctly marked with numerous, obtuse concentric ridges. In the young state the
shell is much flatter than when full grown.

This species is common throughout Europe, extending its range from Sicily on
the south to Sweden in the North.

_ A few specimens of this fragile shell were found by Capt. Alexander, in the
Estuary portion of the Mammaliferous Crag.

Pisipium,* Pfeiffer. 1821.

TELLINA (sp.). Linn.

Carpium (sp.). Poli.

Cycias (sp.). Lam.

Pisum. Megerle, 1811, fide Gray.
Pera. Leach, MSS., 1819.
Eueuesta. Id. ,, 1820.
GauitEsa. Costa, 1839, fide Phil.

Generic Character. Shell small, equivalve, inequilateral, subovate, more or less
inflated, somewhat thin; in the recent state subpellucid, and covered with an
epidermis; smooth or concentrically striated. Hinge with one or two cardinal, and

* Etym. Pisum ?

BIVALVIA. 109

two lateral teeth in each valve. Ligament external, situated on the shorter side.
Impressions of the adductors and of the mantle indistinct.

Animal subovate, with its mantle open on the anterior side and the margins
without fringes, united towards the posterior, where it forms a short and single
siphon, the orifice of which is plain; foot large, tongue-shaped, and extensile.

This genus has been separated from Cyc/as in consequence of a difference in their
animal inhabitants, those of Cyclas having the siphon dichotomous, or divided near
the end into distinct tubes, whereas in this it remains single and simple, to the
extremity, and is not so long. The species as yet known are all small, and have
similar habits to the preceding, frequenting ditches or pools of stagnant water, or
where the stream is not very rapid, and like the allied genus they are perfectly
formed in the parent animal before exclusion. They differ also in having the side
on which the ligament is situated, the posterior, shorter than the anterior; in Cyclas
it is the reverse.

It has not as yet been met with in any Deposit of an anterior date to the Newer
Tertiaries.

1. Prsiprum AmMnicum, Miller. Tab. XI, fig. 1, a—é.
TELLINA amMNiIcA. Mill. Verm. Terr. et Fluv., pt. 2, p. 205, 1774.
— — Chem. Conch. Cab., t. vi, p. 138, t. 13, fig. 134, 1782.
a RIVALIS. Maton. Trans. Linn. Soc., vol. ii, p. 44, pl. 13, figs. 37, 38.
— —= Donovan. Brit. Shells, vol. 11, pl. 64, fig. 2, 1801.
CarpIuM amNnicuM. Mon¢é. Test. Brit., p. 86, 1803.
CycLas eaLustris. Drap. Moll. Ter. et Fluv., p. 131, pl. 10, figs. 15, 16, 1805.
— opBiieua. Lam. Hist. des An. s. Vert, t. v, p. 559, 1815.
— — Brown. Must. Brit. Conch., pl. 17, fig. 14, 1827.
— amnica. Turt. Brit. Biv., p. 250, pl. 11, fig. 15, 1822.
— _— Id. Land and F.-W. Shells, p. 15, pl. 1, fig. 5.
— — Lyell. Elem. of Geol., 2d ed., vol. i, p. 227, fig. 103, 1841.
Para FLUVIATILIS. Leach, MSS., fide Jenyns.
Prstpium opLieuum. Pfeiff. Land und Sussw. Moll., pt. 1, p. 124, pl. 5, figs. 19, 20,
and pl. 1, fig. 19, 1821.
— —_— Phil, En. Moll. Sic., vol. ii, p. 31, 1844.
— amnicum. Jenyns, Trans. Camb. Phil. Soc., vol. iv, p. 309, pl. 21, fig. 2.
— —_ Foré., and Hanl. Uist. Brit. Moll., vol. ii, p. 133, pl. 37, figs. 8, 9,
and pl. O, fig. 8, 1849.

Spec. Char. Testa ovata, oblique trigond, ventricosd, sulcato-striaté umbonibus
obtusiusculis.
Shell ovate, obliquely trigonal, ventricose, striated or sulcated, umbones rather
obtuse. "

Length, $ an inch.

Locality. Mam. Crag, Southwold.

Grays, Erith (Jorris), Cropthorn (Strickland), Clacton, Stutton.

Faversham, and Kennet Valley (Pickering). Recent, Britain, France, Sicily.

110 MOLLUSCA FROM THE CRAG.

This is a most abundant shell at Clacton and Stutton, and is subject to a
good deal of variation, both im the outline and in its exterior ornament ; in all varieties
the young shell is generally flatter or more compressed than when full grown; there
is also a difference in the substance of the shell, some specimens are thin and tender,
while others are quite thick and strong. Those which are most flat are also in
general thinner, and have a greater length from the anterior to the posterior, and are
longer also on the hinder side. ‘The specimens from Grays are mostly the thicker
variety, in which the posterior side is remarkably short and truncate, and the striz on
the outside are finer and more numerous: this has been called P. sulcatum (fig. 1, 4),
but it is, I believe, no more than a variety, as a recent acquisition of numerous
specimens show every intermediate alteration to those which are much less inequi-
lateral, and have more distant ridges upon the exterior. These fossils seem to present
rather more differences than any specimens that I have seen of the recent shell, and it
is, therefore, thought desirable to have the two extreme forms represented, in order
more effectually to display these variations. The hinge is furnished with two cardinal
teeth in each valve, one small and simple, the other large and bifid, the posterior one
in the right is bifid, while in the left valve it is the anterior; there is a large promi-
nent lateral tooth before and behind the umbo at nearly equal distances in the left
valve, and two on each side in the right: this hinge line is broad with teeth of cor-
responding magnitude in the thick variety, and in some specimens these form with the
umbo an angle of little more than 90°, whereas in others of the elongated variety that
angular line will be as large as 130°. In the thick variety, the posterior side projects
but very little behind the umbo, nearly the whole of the animal being on the anterior
side of the shell; in other specimens, this side is two fifths as large as the other, and
the shell much less inequilateral. Similar differences may be also observed in the
sculpture of the exterior, they are always ornamented more or less with concentric
or elevated lines of growth, but in some, these markings are numerous, rounded, and
placed close together, while in others they are sharp and narrow with a considerable
plain concave space between them.

It is a common shell in England, in the living state, and has a wide Geographical
distribution in Europe, extending from Sicily to Sweden.

A few specimens also of this species were obtamed by Capt. Alexander from the
Mam. Crag. ;

2. Pisip1umM HreNsLow1anum, Sheppard.

TeLLInA Hensnowiana. Shep. Trans. Linn. Soc., vol. 14, p. 150, 1825.

CycLas APPENDICULATA. Turt. Man. Land and F.-W. Shells, pl. 1, fig. 6.

PERA APPENDICULATA. Leach, MSS., fide Jenyns.

Pisip1um Henstow1anum. Jenyns. Trans. Cam. Phil. Soc., vol. iv, p. 308, t. 21, figs. 6-—9, 1831.
— _ Gray. Man. Land and F.-W. Shells, p. 285, pl. 1, fig. 6.
~— — Forb, and Hanl, Hist. Brit. Moll., vol. ii, p. 131, pl. 37, fig. 11, 1849.

BIVALVIA. 111

Spec. Char. Testé minutd, obliqud, sub-ovatd, valdé inequilaterd, tumida ; anticé
productiore attenuata, vel diminuatd ; umbonibus prominulis et appendiculatis.

Shell minute, oblique, sub-ovate, very inequilateral, and generally ventricose ;
anterior side much the longer; umbones slightly prominent. furnished with a
projecting appendage.

Length, +th of an inch.

Locality. Clacton, Stutton, Cropthorn (Strickland), Grays (Pickering).

Recent, Britain, Ireland, Germany.

This is an abundant shell at the localities, Clacton and Stutton, where they are
often found with the valves united.

The form is somewhat variable, but in general it may be described as triangularly
ovate, the posterior side being higher, that is from the umbo to the ventral margin,
diminishing towards the anterior side which is narrower and rounded, it is very
inequilateral and tumid, having at the umbo an appendage or projection, which is
its most distinguishing character.

3. PISIDIUM PULCHELLUM, Jenyns.
PERA PULCHELLA. Leach, MSS., fide Jenyns.
PIsIDIUM PULCHELLUM. Jenyns, Trans. Camb. Phil. Soc., vol. iv, p. 306, t. 21, figs. 1—3,
1831.
— Gray. Man. Land and F.-W. Shells, p. 284, pl. 12, fig. 151.
== — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 128, t. 37, figs. 12,
13, 1849.
— FONTINALE. Brown. Illust. Brit. Conch., 2d ed., pl. 39, fig. 23.
_— — Pfeiffer. Land und Sussw. Moll., pt. 1, p. 125, t. v, figs. 15, 16,
1821.
— — Phil. En. Moll, Sic., vol. ii, p. 31, 1844.
CycLas FONTINALIS. Drap. Moll. Terr. et Fluv., p. 130, t. x, fig. 12?
GaLILEsA TENEBROSA. Da Costa. Corresp. Zool., fide Phil.

Spec. Char. Testé minutd, oblique-cordatd, valdé inequilaterd, ventricosd, concentricé
striata, tenui, fragili ; umbonibus prominulis.

Shell small, obliquely heart-shaped, very inequilateral, ventricose, finely striated
concentrically, thin and fragile ; umbones slightly prominent.

Length, +th of an inch.

Locality. Stutton, Clacton, Grays (Pickering), Copford (J. Brown).

Recent Britain, France, Sicily.

This appears to be by no means a rare shell in any of the above localities, though
it is less abundant than Henslowianum at the two former, and like the recent shell it
is subject to much variation.

112 MOLLUSCA FROM THE CRAG.

4. Pisiprum pusittum, Turton.
TELLINA PuSILLA, Turt. Conch. Dict., p. 167, 1819.
Cycuas pusitua. Turt. Brit. Biv., p. 251, t. 11, figs. 16, 17, 1822.
— — Id. Wand and F.-Water Shells, pl. 1, fig. 7.
— arpBa. Alder. Trans. Nat. Hist. Soc., Newcastle, vol. i, p. 41.
— rontrnatis. Drap. Moll. Terr. et Fluv. France, p. 130, pl. 10, fig. 8, 1805.
Euaiesia Henstowiana. Leach, MSS., fide Jenyns.
PIsIDIUM PUSILLUM. Jenyns. Trans. Camb. Phil. Soc., vol. iv, p. 302, t. 20, figs. 4—6,
1831.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 123, t. 37, fig. 10, and
pl. O, fig. 9, 1849.

Spec. Char. Testé pusilld, orbiculato-ovatd, compressiusculd, subinequilaterd, subti-
lissimé striata ; umbonibus prominulis.

Shell small and slender, roundedly ovate, somewhat compressed, slightly inequi-
lateral, very finely striated; umbones but little projecting.

Length, th of an inch.

Locality. Clacton, Copford (J. Brown), Grays (Pickering). Recent, Britain, France.

This species is by no means abundant in my Cabinet from the former locality,
while Mr. Brown has found it in large numbers, in what is, perhaps, a more Modern
deposit at Copford. The principal distinction of this shell appears to be its generally
greater gibbosity ; it is less inequilateral than any of the other species.

We have thus, it seems, four well determined species in this genus from the
purely Fresh-water Deposits of this Kingdom, while the living British Pzs:dia have
been separated by British Conchologists into not less than eight or nine. I confess,
not to be very well acquainted with the recent forms, but judging from a general
knowledge of the variability amongst the fresh-water shells in particular, I think too
much dependence has been placed upon differences, arising from locality and other
external causes, and that slight variations resulting therefrom have been considered of
sufficient importance for the establishment of distinct species; I am inclined to
belieye, all the forms existing in England might be included in four or at most five
species.

In the beautiful and extensive collection of British Land and Fresh-water
Molluscs, in the Cabinet of Mr. John Pickering, are numerous forms of this genus,
and I have applied to that gentleman for his assistance upon the recent as well as
fossil Pisidia, and as he has devoted many years to the examination of these animals,
I conceive his opinion to be of much more value than my own; he says (in Lit.) “I
am of opinion, we have not more than five species of Pisédia in this country, viz.,
P. amnicum, P. Henslowianum, P. pulchellum, P. obtusale, and P. pusillum. After
selecting the first three species, there are many forms remaining, from which without
much difficulty may be selected puse/lum which appears a less variable species than
most of the others; then follows odtusale the most variable of the whole, differing in
almost every locality, in some comparatively large and free growing, in others small

BIVALVIA. 113

and stunted according to the nature of the habitat, changing its form in each stage of
growth from compressed and decidedly inequilateral, to very tumid and nearly
equilateral, even in the same locality, yet merging so imperceptibly into each other,
that they cannot be separated without dismembering what appears to me a good and
natural species ; and it is yet a doubt in my mind whether on a fuller investigation of
the genus, ‘pusz/lum’ can continue to rank as a species.”

‘These opinions have not been suggested by the sight of a few isolated and typical
forms, but after a long and patient examination of several hundred specimens, col-
lected in various localities in the counties of Berks, Cumberland, Devon, Dorset,
Essex, Hants, Herts, Kent, Lancashire, Middlesex, Northumberland, Surrey, Sussex,
and Yorkshire.”

In the form of my fossil specimens of pwsid/um, I can see no material difference
from odtusale, except that in the latter the shell is more tumid; but the differences
between the two do not appear to me to be more evident than some of the forms are
in the fossil Cyclas cornea, where specimens are occasionally excessively tumid, while
others of the same length and height are much compressed, and the like differences
are observable in specimens of P. amnicum. The few individuals of these last two
species, that I have seen from the Mam. Crag, are of the ordinary form or intermediate
between the extremes we have had figured.

LeptTon,* Turton, 1822.

SoLEN (sp.). Mont., 1803.
LurraRia (sp.). Gray, 1825.
PsamMosia (sp.). Brown, 182/.
Enycina (sp.). Myst, 1844.

Generic Character. Shell equivalve, subequilateral, ovate, or subtrigonal, thin
and compressed; umbones more or less acute, not prominent; surface elegantly
ornamented; margin plain; hinge composed of two diverging teeth in each valve,
between which is placed the ligament wholly internal. Impression of the mantle
simple or without a sinus.

The animal of this genus is said to have its mantle freely open in front with a-fringe
all round the margin, and capable of extending itself considerably beyond the. shell ;
a short siphonal tube with a single aperture, and a thick foot furnished with a byssal
groove ; one of the filaments of its marginal fringe is longer and larger than the others.

In addition to the two recent British species, the Crag contains one quite distinct, with
another doubtful one resembling what appears to be a different species in the Campinian
beds of Belgium. Conrad also describes one living in the Seas of America, as well as
another from the Upper Tertiaries of that country, but few specimens of either of

* Etym. Aezros, thin.
15

114 MOLLUSCA FROM THE CRAG.

these have been examined carefully, and their correct specific establishment is not at
present upon a firm and stable basis; and my own species are not given with any
great confidence, but more to call the attention of Collectors to their probable
existence.

Specimens apparently belonging to this genus have also been obtained at Barton
from the London Clay or Older Tertiaries.

1. Lepton squamosuM, Montague. Tab. XI, fig. 8.
Soten saquamosus. Mont. Test. Brit., p. 565, 1803.
— — Mat. and Rack. Linn. Trans., vol. viii, p. 48, 1807.
— — Turt. Conch. Dict., p. 164, 1819.
_ _ Dillw. Desc. Cat. Rec. Shells, p. 70, 1817.
= — W. Wood. Ind. Test. p. 16, 1825.
PsamMosBia PuNcTURA. Brown. Illust. Conch. Gr. Brit., pl. 16, fig. 7, 1827.
Lepton squamosum. Turt. Brit. Biv., p. 62, pl. 6, figs. 1—3, 1822.
— — Flem. Brit. An. p. 429, 1828.
— — S. Wood. Catalogue, 1840.
— = Thorpe. Brit. Mar. Conch., p. 49, 1844.
— — G. Sowerby. Conch. Man., fig. 62, 1843.
— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 98, pl. 36, figs. 8, 9,
and pl. O, fig. 6, 1849.
LuTrarra squamosa. Gray. Ann. of Philos., 1825.
a — Hanley. Recent Shells, vol. i, p. 28, Supp., pl. 9, fig. 47.
Lepron squaMEuUx. Chenu. Traité Elem., p. 47, fig. 148.

Spec. Char. Testé ovato-trigonuld, equilaterali, compressa, tenui; utroque latere
rotundatd, margine ventrali leviter arcuatd; eleganter ornata; dente cardinal unico, dentibus
lateralibus magnis.

Shell small, triangularly ovate, equilateral, thin, compressed; rounded on both
sides, ventral margin slightly arched; elegantly ornamented externally ; hinge with
one small central tooth and two large lateral teeth.

Length, % of an inch.

Locality. Cor. Crag, Sutton. Recent, British Seas.

One specimen only of this species was found by myself in the sandy portion of
the Coralline Crag, at Sutton. The interior is sufficiently perfect for comparison, but
the markings upon the exterior are rubbed and obliterated, and although there is
some slight difference in the outline of our shell, there is every reason to believe it
belongs to the same species as that now living in the British Seas, and to which I have
assigned it. The hinge area is large, furnished with a small central tooth, and a
double set, as it were, of lateral teeth, the innermost of which are large, diverging at
an angle of about 90°, those placed outwardly are small and close to the dorsal
margin, between these are deep depressions for the reception of the lateral teeth of
the opposite valve. The dorsal margin is short, not extending beyond the lateral

BIVALVIA. 115

teeth, it then slopes to the sides which are both rounded, and the ventral margin is
also slightly convex, differing thus a little in not presenting quite such a quadrate
form as the recent shell; perhaps a larger number of individuals both recent and fossil
would present a greater resemblance. The beautiful sculpture which ornaments the
recent shell, is replaced in the fossil by a granulated surface, the effect of probably
unequal erosion, and the semipellucid appearance is changed into an opaque one from
the loss of its animal matter. Two ovate rather deeply impressed muscle marks are
distinctly visible in my specimen, which measures barely a quarter of an inch in
length, and a little less in height.

2. LEPTON DELTOIDEUM, S. Wood. Tab. XI, fig. 9, a—d.

Keira DELTOIDEA. S. Wood. Catalogue, 1840.

Spec. Char. Testd subtriangulatd, vel deltoided, equilateral, tumidd, polita, fragili ;
utringue rotundatd, margine ventral recta ; dentibus lateralibus approximatis.

Shell triangular or deltoidal, equilateral, tumid, glossy, and fragile; anterior and
posterior sides rounded with the ventral margin straight, lateral teeth approximate.

Length, } aninch. Height, =4;ths.

Locality. Cor. Crag, Sutton, Ramsholt.

Red Crag, Sutton.

This delicate and very elegant species is not particularly scarce in the Coralline
Crag, where I have procured more than a couple of dozen specimens, and notwith-
standing its extreme fragility, its presence in the Red Crag is also undoubted, two
specimens belonging to that Formation are in my Cabinet, where they have been for
many years, but their exact locality is uncertain, as the label has been unfortunately
lost. We may fairly presume it to have prolonged its existence into the Period of the
latter Deposit, as such delicate shells could only under very favorable protection
have survived, being washed from an Older into a Newer Formation, and I give them
without hesitation as natives of the Seas of that part of the world in both Periods.

I am not acquainted with any described species to which this can with certainty be
assigned. Bornia corbuloides, Phil., En. Moll. Sic., vol. i, p. 14, t.1, fig. 15, somewhat
resembles it in outline, but the difference as given by the description appears
to present characters sufficient to keep them distinct, bemg recorded to have
its margin crenulated on both sides, which our shell certainly has not.

Lepton fabagella, Conrad, a very indifferent figure of which is given by Dekay,
in the ‘ Nat. Hist. of New York,’ a little resembles our shell in outline, and a fossil
species by Conrad, Lepton mactroides, from the Upper Tertiaries of America, present
general or generic resemblance, but the specimens must be examined for correct
determination, and I have not been able to see any of the three species above referred
to: our fossil must, therefore, for the present, remain with the name originally imposed

116 MOLLUSCA FROM THE CRAG.

in my Catalogue. The shell is very thin, and in the living state was no doubt nearly
transparent, it has a prominent umbo, sloping towards each extremity, and is rounded
there, while the ventral margin is quite straight, even inclining a little inwards in
some specimens, and is deep or tumid, particularly at the upper part; the hinge is
furnished with two teeth in each valve, diverging from the ligamental area, but do
not extend far towards the sides, and in the left valve immediately beneath the umbo,
and before the ligament, is a small cardinal tooth, but not one in the right valve; in
perfect specimens the shell is beautifully glossy, and the exterior possesses a sort of
irregular concentric striz, which I imagine is not its original appearance, and that
probably it was ornamented in its recent state with more elaborate sculpture.

3. LepTton pEepReEssuM, JVyst. Tab. XI, fig. 6.

Cycias? pepressa. Nyst. Rech. Coq. Foss. d’Anv., p. 36, pl. 5, figs. 5, 6, 1836.
ERYCINA DEPRESSA. Myst. Coq. Foss. de Belg., p. 88, pl. 4, fig. 5, a, a, b, ¢, e, 1844.

Spec. Char. Testa transversd, ovata, inequilaterali, depressd, tenui; dente cardinali
unico, dentibus lateralibus obtusis.

Shell transversely ovate, slightly inequilateral, depressed and thin: hinge with one
cardinal, and two obtuse lateral teeth.

Length, + of an inch.

Locality. Cor. Crag, Sutton.

A single specimen of this shell in my Cabinet seems to correspond with what M. Nyst
considers, probably with better materials than I possess, to be a distinct species, and
the form certainly is different from that of any other already described; and as I am
not imposing a new name, it will at least serve to call the attention of Collectors to
its existence for better examination.

My specimen may be thus more particularly described. One side is rather broader
or deeper than the other, the longer side being the more narrow, and slightly pointed,
the hinge teeth are very obtuse, perhaps not quite perfect, dorsal area truncate, with
a depressed umbo: lateral teeth not very distant, two ovate muscular impressions
rather deep, and a continuous line formed by the mantle. The exterior is somewhat
rough and eroded, but appears as if it once had a more regular ornament. M. Nyst

says of his shell: “ Transversim subtilissimé irregulariterque striata,’ and that it is
in Belgium also a rare species.

4. LEpton NiTIDUM, Turton. Tab. XI, fig. 7.
LEPTON NITIDUM. Turt. Brit. Biv., p. 63, 1822.
a — Flem. Brit. An., p. 429, 1828.
— _— S. Wood. Catalogue, 1840.
— — Thorpe. Brit. Mar. Conch., p. 49, 1844.
oo —_ Macgill. Moll. Aberdeen, p. 278, 1843.
Kevuia nitipa. Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 92, pl. 36, figs. 3, 4, 1849.

BIVALVIA. i if

Spec. Char. Testa minutd, ovata, subinequilaterali, compressa, tenui, fragilt ; dente
cardinali unico ; dentibus lateralibus magnis, distantibus.

Shell small, ovate, nearly equilateral, compressed, very thin, and fragile; hinge
with one cardinal tooth, and two large and distant lateral teeth.

Length, $th of an inch.

Locality. Cor. Crag, Sutton. Recent, British Seas.

When compiling my Catalogue, one specimen of a shell strongly resembling the
description given by Turton as a distinct species of Lepton, was in my Cabinet, and
Iam sorry to say it is the only one I have as yet seen. As the authors of the ‘ Hist.
of British Mollusca’ confirm its existence in the recent state, and have given a good
distinguishable figure, I am able with a little more confidence to describe my shell
under the name originally given. My solitary specimen possesses characters more in
accordance with the diagnosis of Lepton than of Kellia, as given by the proposer of
the two Genera, both as regards the hinge as well as the shell. My specimen is; I
suppose, the left valve having the cardinal tooth before the ligament, which is placed
in a triangular fossette immediately within a slightly prominent umbo, two large
lateral teeth extend to the edge of the dorsal area, and the two sides are a little
unequal in size, the anterior being a trifle the larger, and the less rounded ; the shell
appears to have been very thin, and the impression of the muscles indistinct, while
the exterior is somewhat rough and uneven, as if it had been altered by erosion.

Kewuia,* Zurton, 1822.

AMPHIDESMA (sp.). Lam., 1818. Bornia. Pahil., 1836.
Laszea. Leach, MS., 1819. Brown, 1827. Auigpena. H. C. Lea, 1843.
Erycina (sp.). Desh., 1824. Scaccuta (sp.). Phil., 1844.
Perricgua (sp.). Gray, 1835. Myautna? Conrad, 1845.
TeLLimya (sp.). Brown, 1827. Poronta. Reeluz., 1846.
Cyztapina. Cantraine, 1830. Cutronia. Desh., sec. Gray.

Generic Character. Shell generally small and thin, equivalved, subequilateral,
orbicular, spheroidal, ovate, or roundedly-oblong; tumid, or compressed; surface
smooth, or covered with visible lines of growth. Hinge composed of two, sometimes
only one, tooth in each valve, with a trigonal pit for the reception of the ligament,
which is within the margin of the shell, though visible in some species when the
valves are closed. Impressions by the adductor muscles suborbicular, often indistinct,
that by the mantle without a sinus.

Animal of the form of the shell, with the edges of the mantle disconnected
only in places, extending posteriorly into one short siphonal tube, and at the anterior

* Etym. Name commemorative of J. M. Kelly, Esq.

118 MOLLUSCA FROM THE CRAG.

side there is a prolonged canal with an opening for the protrusion of its foot, at
the base of which is a byssal gland and groove.

This genus was proposed by Dr. Turton for the reception of two small species of
British shells, one of which had been previously placed in the genus Mya, and the
other in that of Cardium.

The species known, belonging to this genus, are somewhat minute but elegant
bivalves, which in the living state are usually found located either in rocks or seaweeds,
though most of them are capable of spinning a byssus; they possess a considerable
vertical range, some living near low water mark, while others inhabit the sea at the
depth of 50 fathoms. They appear to have been somewhat largely developed in the
Corallme Crag Period, and are invariably found free or loose in the sand, and if ever
imbedded it must have been in the leaves or roots of seaweed, or in some material
which by decomposition or disintegration has liberated them from their confined
position. All my specimens were found in one locality, where there is a large accumu-
lation of numerous small species. This genus has been obtained in considerable abun-
dance from the Older Tertiaries of this country, and several species enrich the Cabinet
of my friend F. E. Edwards, Esq. There has not been anything found in the secondary
Formations that can with certainty be referred to this genus, although a shell in the
Green-sand strongly resembles it.

One or two species from the Crag included under this generic title possess
characters that will perhaps scarcely come within the range of our diagnosis. A
considerable variation may be observed in their dental arrangement, some being
furnished with two or more of these appendages, while others seem to be wholly
deficient, an internal ligament placed in an oblique depression appears an universal
character.

1. KELLIA SUBORBICULARIS, Montague. Tab. XII, fig. 8, a, 4.
Mya suporBicuLarts. Mont. Test. Brit., pp. 39, 564, t. 26, fig. 6, 1803.
_ — Mat. and Rack. Linn. Trans., vol. viii, p. 41, 1807.
— — Dillw. Des. Cat. Rec. Shells, p. 55, 1817.
TELLINA sUBORBIcULARIS. Twurt. Conch. Dict., p. 179, 1819.
AMPHIDESMA PHYSOIDES. Lam. Hist. des An. s. Vert., t. y, p- 493, 1818, fide
G. B. Sow.
KELLIA suBoRBIcULARIS. Turt. Brit. Biv., p. 57, t. 11, figs. 5, 6, 1822.
— — Flem. Brit. An., p. 430, 1828.
a — Maegill. Moll. Aberd., p. 276, 1843.
— — Thorpe. Brit. Mar. Conch., p. 51, 1844.
— _ J. Sowerby. Min. Conch., t. 637, fig. 1.
— — Lovén. Ind. Moll. Scand., p. 44, 1846.
a — Alder, Cat. Moll. North. and Durh., p. 93, 1848.
— — Forb. and Hani. Hist. Brit. Moll., vol. ii, p. 87, pl. 18, fig. 9,
a, 6, and pl. O, fig. 4, 1849.
KELLIA LactEA? LLovén. Ind. Moll. Scand., p. 44, 1846.

BIVALVIA. 119

TELLIMYA SUBORBICULARIS. Brown. Illust. Conch. Gr. Brit., pl. 14, figs. 14, 15, 1827.
TrLLIMyA LAcTEA? Id. - - - - pl. 14, figs. 10, 11.
_ TENUIS. Id. - - - - pl. 14, figs. 12, 13.
— — Smith. Wern. Trans., vol. viii, p. 45, 1838.
Bornta InFuLATA. . Phil. En. Moll. Sic., vol. i, p. 14, and vol. ii, p. 11.
Erycrna Pisum. Scacchi. Catal., p. 6, figs. 1 and 2, 1836.

Spec. Char. Testé tumidé, orbiculato-oblongd vel suborbiculari, subequilaterali, tenui,
fragili; strits tenuibus incrementi distinctis; cardine bidentato, dentibus lateralibus
remotis.

Shell tumid, roundedly-oblong or suborbicular, nearly equilateral, very thin and
fragile ; smooth or covered with very fine lines of growth; hinge with two cardinal
teeth in one valve and one in the other, lateral teeth remote.

Diameter, + of an inch.

Locality. Coralline Crag, Sutton.

Red Crag, Walton Naze.
Recent, Britain, Scandinavia, and Mediterranean.

The animal of this species, which may be considered the type of the genus, has
been examined by Mr. Alder, and a description published in his valuable Catalogue of
the ‘Mollusca of the Coast of Northumberland’ (page 94), where he has pointed out a
remarkable deviation from the normal form of the Bzvalvia, which in general have the
siphonal tube or tubes, when they exist, placed at the posterior side of the shell, while in
this one, in addition to a short siphon in its natural position, there is a large tube capable
of being projected a considerable distance on the anterior side. The mantle has three
openings, he says, one posteriorly for the usual siphon which scarcely projects beyond
the margin of the shell; another in front in the form of a tube, which is protruded when
the animal is in a state of activity, toa distance equalling the diameter of the shell; and
the third is for the emission of a long subcylindrically-formed foot, at the base of which
is a small opening and gland for the production of delicate threads or filaments, whereby
the animal is enabled freely to suspend itself in the water to some foreign body
although it is more often found located in the aperture of a rock.

A considerable degree of variation in form may be observed among the shells of
this species in the recent state, but it is more particularly so with those which are
found in the crevices of rocks, which probably in some measure distort or alter the
otherwise natural form of the shell. This species is not by any means common in the
Coralline Crag.

The more general form of my fossils is nearly orbicular, but one specimen (fig. 8, 4)
is more transverse, or has a greater diameter from the anterior to the posterior
extremity: the same differences exist in those now found in our own seas. The Red
Crag at Walton Naze has furnished me with one specimen. It is said to range from
low-water mark to a depth of 60 fathoms.

120 MOLLUSCA FROM THE CRAG.

2. KELuIA oRBICULARIS, S. Wood. Tab. XII, fig. 9, a—e.
Keita? orpicuntaris. S. Wood. Catalogue, 1840.
— _ J. Sowerby. Min. Conch., t. 637, fig. 2, a. 1844.

Spec. Char. Testd minutd, orbiculart, tumidd, obliqua, subequilateral, clausa ;
concentrice et rugose striatd ; latere postico breviore ; dente cardinali unico in utraque
valva ante foveam ligaments ; fovea triangulari, obliqua, profundd.

Shell small, orbicular, or spheroidal, inflated, subequilateral, closed; roughly
striated concentrically; posterior side the shorter; one cardinal tooth in each valve
before the ligament ; ligamental pit oblique, deep, and of a triangular form.

Diameter, + of an inch.

Locality. Cor. Crag, Sutton.

This is more abundant than the preceding species, and is limited, as far as I
know, to one locality. I have not been able to trace it higher up in the Series,
or nearer to our own time than the Cor. Crag. A shell called Scacchia iversa,
(Philippi, Kin. Moll. Sic., vol. ii, p. 27, T. 14, f. 10,) resembles this in some respects,
but differs in others, sufficiently, it is presumed, to be considered specifically distinct,
depending upon the figure and description by Philippi.

The ligament is wholly internal, and the pit for its reception is an oblique,
angular depression beneath or within the dorsal margin, extending backwards to
some distance, with a ridge or ledge for its support. The umbo is prominent, and
there is a considerable obliquity in the shell; an obtuse kind of ridge slopes from the
umbo towards the anterior ventral margin, behind this the shell is a little flattened,
giving a squarish outline by a somewhat straightened ventral margin. The left valve
has the larger tooth, this is situated a little in advance, and not immediately beneath
the umbo; the cardinal tooth of the right valve is placed further backward, and
locks in behind the larger tooth of the opposite valve, making that tooth appear in
some specimens to have a ledge, or another rudimentary one. In the figure of this
species in Min. Conch., the teeth are represented as of equal size, but there is an evident
inequality, neither are they both in the same position, there is no vestige of a tooth
on the posterior margin, in which character it differs from any of the three figures
given by Brown in his ‘Illustrations of British Conchology.’ Conrad, in his
‘American Miocene Fossils,’ figures and describes a similar species under the name of
Amphidesma equata, p. 65, Pl. 36, f. 5, but the figure is so inferior, and the descrip-
tion so brief, that it is impossible to institute a fair comparison.

3. KELLIA amBicua, WVyst. Tab. XII, fig. 11, a, 4.
CorBuLa amBicua. Nyst.and West. Nouv. Rech. Coq. Foss. d’Anyv., p.6, pl. 3, figs 4, 1839.
Erycina ampicua. Nyst. Coq. Foss. de Belg., p. 89, pl. 4, fig. 6, a, 6, 1844.
— srriatuna. Id. - =) =D. OO ph. 4. ie saves
KeLi1a puBia. S. Wood. Catalogue, 1840.
— on J. Sow. Min. Conch., t. 637, fig. 4, a, 6, 1846.
= _ Tennant. Strat. List. Brit. Foss., p. 15, 1847.

———

BIVALVIA. 121

Spec. Char. Testé transversd, elongato-ovatd, equilateral, leviter convead, levigata:
vel tenuissime striata ; utrinque rotundatd, dente cardinal unico, obtuso ; lateralibus nullis,
fovea ligamenti elongata obliqud. |

Shell transverse ovate, equilateral, slightly convex rounded at both extremities,
smooth, or with very fine lines of growth; hinge with one cardinal tooth, no lateral
teeth, ligamental area elongated, and oblique.

Length, ths. Hezght, =',ths. of an inch.

Locality. Coralline Crag, Sutton.

Red Crag, Walton Naze, and Sutton.
Mam. Crag, Chillesford.

This shell is abundant in the Coralline Crag, but the specimens are generally small,
rarely exceeding half an inch. Fig. 11, 4,is from the Red Crag, and measures at least
three quarters of an inch. Among alarge number of individuals a considerable varia-
tion may be observed, but these differences are principally in the proportional dimen-
sions, although some specimens have occasionally a more triangular form (fig. 11,@). It
is furnished with one somewhat prominent but obtuse tooth in the right valve, with a
depression before it, and in the left valve there are two teeth, when perfect, which is
not often the case, one immediately beneath the umbo, erect and compressed, the other
decumbent along the margin and at right angles to the other; the ligamental area slopes
obliquely backwards, forming a thickened ridge, against which it rested. The impressions
by the adductors are large and rather elongated, while that formed by the edge of the
mantle is at some distance within the margin of the shell, and is without any inflection,
and in some thin specimens from the Coralline Crag, fine radiating lines are visible in
the interior.

This is the largest species of Kellia that lam acquainted with, and strongly resembles
in form a shell from the Paris basin, to which it was assigned in my Catalogue; but
by a comparison with a specimen from the Older Tertiaries of this country, now in the
cabinet of Mr. John D'Urban, and which probably is identical with the Psammotea dubia,
Desh, a material difference is exhibited sufficient to prove them specifically distinct, as
in that shell the ligament is placed on the outside, whereas in ours itis wholly internal.

A recent species from the Coast of Lower California, described and figured by
Conrad in the ‘ Journal of the Acad. of Nat. Sci.,’ Philadelphia, 1850, Art. xxu, p. 279,
pl. 39, fig. 1, under the name of Solecardia eburnea, has a strong generic relationship
with our Crag fossil, although no doubt specifically distinct.

4, KELLIA ELUIPTICA, Scacchi. Tab. XII, fig. 138, a—e.

TELLINA ELLIPTICA. Scacchi. Oss. Zool., ii, p. 14, 1833,) Pitty i

Loripes ELLIPTICUS. Scacchi, Ejusd. Cat., p. 5, fig. 1, ae J SEED

Luctna oBLonGA. Phil. En, Moll. Sic., vol. i, p. 34, t. 4, fig. 1, 1836.

KELLIA FLEXUOSA. S. Wood. Catalogue, 1840.

— _ J. Sowerby. Min. Conch., t. 637, fig. 5, a, 1844.

Scaccusa ELLIpTIcA. Phil, En. Moll. Sic., vol. ii, p. 27, t. 14, fig. 8, 1844.

16

122 MOLLUSCA FROM THE CRAG.

Spec. Char. Testa transversd, ovatd vel ellipticd; valdé inequildterali, convewd,
levigaté, politd, tenut ; anticé productd, utrinque rotundatd ; margine dorsali flexuosd ;
cardine valvuld sinistrd bidentato ; dentibus lateralibus nullis.

Shell transverse, ovate or elliptical, convex; very inequilateral, smooth, glossy, and
thin; anterior portion much the larger, and rounded at both extremities; dorsal
margin sinuated ; hinge with two cardinal teeth in left valve ; no lateral teeth.

Length, 2;ths. Height, #th of an inch.

Locality. Coralline Crag, Sutton. Recent, Mediterranean.

A large number of this pretty little shell have been obtained at the rich Depot
of Molluscan remains at Sutton, where the two valves are occasionally, though
rarely, found united.

The most distinguishing mark of this species is the peculiar sinuosity of the upper
margin of the shell on each side of the umbo in both valves, but that in the right one
is the most conspicuous; a sinus or rather an indentation at a considerable, but about
an equal distance both before and behind the umbo, received the edge of the margin
of the left valve by which it is a little twisted, thus interlocking and serving the office
of lateral teeth. The hinge is furnished with one obtuse tooth in the right valve with
a deep depression immediately before it; in the left valve are two teeth, one of which
is somewhat prominent and compressed, the other placed at right angles to it and in
a line with the margin; these two, when the valves are closed, occupy a position on
each side of the single tooth of the right valve. The ligamental area is small and
oblique, sloping towards the posterior side; the muscular impressions are large and
distinct, and the mantle mark without any inflection.

I have not been able to compare my shell with the recent Mediterranean species,
but from the peculiar character of a flexuous margin there cannot be much doubt of
its identity; my specimens do not appear quite so large as the one represented by
Philippi.

Scacchi’s name is restored upon the authority of M. Philippi.

5. Kenia cyciapia, 8S. Wood. Tab. XI, fig. 4, a, 4.
Keiita cycLapia. S. Wood. Catalogue, 1840.
— oo J. Sowerby. Min. Conch., t. 637, fig. 6, a, 1844.
Scaccuta ovata? Phil, En. Moll. Sic., vol. ii, p. 27, t. 14, fig. 9, 1844.

Spec. Char. Testa transversd, obliqud, tumida, ovato-trapezoided, valde inequilaterali,
tenut, fragilr ; margine dorsali integerrimo ; anticé majiore, posticé subrecto ; dente cardinali
unico, dentibus lateralibus nullis.

Shell transverse, oblique, tumid, of an ovate trapezoidal outline ; very inequilateral,
thin and fragile; dorsal margin without any inflection; anterior side the larger,
posterior nearly straight ; one cardinal tooth and no lateral teeth.

Length, + of an inch nearly.

Locality. Coralline Crag, Sutton. Recent, Mediterranean.

BIVALVIA. 123

Two or three specimens only of this delicate and fragile shell were all that I
possessed when Mr. Sowerby figured and described it in ‘ Min. Conch.,’ and I am sorry
to say I have seen none in addition to that number. A recent shell from the
Mediterranean above referred to, seems to correspond in most characters with our
own, and [I should imagine there was no doubt of the identity, but that the Crag shell
is wholly destitute of lateral teeth, which M. Philippi describes as being distinct in
his species. The hinge was probably furnished with one cardinal tooth in the right
valve and two in the left, but in my specimens of both valves they are nearly obsolete.
The recent shell was no doubt in a better state of preservation and more to be de-
pended upon.

Its outward form and absence of all flexuosity in the margin will distinguish this
from the preceding, which probably it resembled in its dentition. In the general
form and fragile texture it much resembles one of the Freshwater Cyclades, whence its
specific name.

Amplidesma equalis, Conrad, ‘ Amer. Mioc. Foss.,’ p. 76, Pl. 43, fig. 9, in outward
form is somewhat like our shell, but the figure, as with 4. equata, is not sufficient for
comparison, and the description is too concise to supply the deficiency.

6. Keiira coarcrata, S. Wood. Tab. XI, fig. 10, a, 4.
Keira coarctata. S. Wood. Catalogue, 1840.
GaLEomMA comprEssuM? Phil. En. Moll. Sic., vol. ii, p. 19, t. 14, fig. 5, 1844.

Spec. Char. Testd minutd transversd, oblonga, levigatd, politd, compressa, subequi-
laterali ; antice majiore, dente cardinali unico in utraque valvd, lateralibus nullis ; margine
ventrali recto, vel coarctato.

Shell small, transverse, oblong, smooth, and glossy, compressed nearly equilateral,
anterior side the larger; hinge with one cardinal tooth in each valve, lateral teeth
none, ventral margin straight, or subsinuated.

Length, ds. Height, 3th of an inch.

Locality. Corallme Crag, Sutton.

Two or three dozen specimens of this species are in my Cabinet, all from one
locality. The form of the shell is somewhat oblong, rounded at the corners;
the posterior side is not only the shorter, but is rather narrower; the dorsal margin of
the anterior side being nearly straight, while the posterior has a gentle slope by which
that side is a little diminished. The exterior in perfect specimens has a beautiful
glossy appearance, and it was probably in the living state a semitransparent shell.
There is one tooth in each valve, that in the right is the larger and more prominent,
behind this is the ligament, placed on an oblong kind of shelf, inclining inwards on the
posterior side, the edge of this shelf is in some individuals slightly elevated above the
margin, and might be mistaken for another tooth; the lines of growth are occasionally
visible but no regular strize, and the impressions of the muscles are not distinguishable.

124 MOLLUSCA FROM THE CRAG,

In dental characters and position of the ligament it corresponds with some of the
other species included in this genus, and appears to be more closely allied to it, than
to Galeomma in which Philippi has placed his shell, which is considered here with
doubt as an identity.

One specimen of mine has the two valves united, but does not show an opening
at the ventral margin, a character essential to that genus; there is a twist in the
shell, and the single valve, when laid with its margin downwards, will not touch on all
sides, and this bend in the opposite valve is in the contrary direction, so as to bring
the margins of the two pieces together at all parts when the valves are closed; never-
theless there is something about it peculiar to itself as possibly not to belong to either
this or to Galeomma.

7. KeLui1a pumita, S. Wood. Tab. XII, fig. 15, a, 6.

Montacuta pumILA. 8S. Wood. Catalogue, 1840.
Kriya pumita. J. Sowerby. Min. Conch., t. 637, fig. 3, 1846.

Testa minima transversd, ovata, obliqua, tumidd, valdé inequilaterali, levigaté, politd;
anticé majiore et longiore, utrinque rotundatd ; dente cardinali unico, dentibus lateralibus
magnis.

Shell small, transverse, ovate, oblique, tumid, very inequilateral, smooth, and
glossy ; anterior side much the larger and longer, both sides rounded; hinge with
one cardinal tooth, and two lateral teeth.

Diameter, =!5th of an inch.

Locality. Cor. Crag, Sutton.

This is a very abundant shell at the above locality, where the two valves are
often found united, their large and prominent teeth having kept them in their natural
position.

Without allowing a latitude in variation beyond what we are accustomed to do,
even with such variable species as were the inhabitants of the Crag Seas, this shell
can scarcely be admitted as an identity with the A. ruéra, although it bears a close
approximation ; and as the Malacologists have placed the recent shell in Ked/ia, it is
thought best to follow their example, although it does not strictly accord in its dental
characters with the diagnosis of that Genus.

Our shell is more inequilateral than A. rubra, and the hinge is quite at the side,
the umbo being almost terminal, and the posterior lateral tooth then forms nearly a
right angle with the beak and anterior lateral tooth: in the recent shell the hinge
is much more central, with less of gloss upon the exterior; ours was perhaps a more
transparent shell, with the teeth rather less distinct: thus differing more from the
Mediterranean shell, according to Messrs. Forbes and Hanley, than from the British ;
there are two prominent lateral teeth, with a central one in the right valve, and
two smaller nearly obsolete lateral teeth in the left valve.

BIVALVIA. 125

Turton, in his ‘ British Bivalves,’ p. 258, states the animal of this species to be
viviparous, and that he found many specimens filled with perfectly formed young ones,
similar in habit to the Genus Cyclas.

8. KELLIA RUBRA, Montague. Tab. XI, fig. 10.
CarpiuM RUBRUM. Mont. Test. Brit., p. 83, t. 27, fig. 4, 1803.
= — Mat. and Rack. Linn. Trans., vol. viii, p. 66.
— — W. Wood. Ind. Test., p. 24, 1825.
TELLINA RUBRA. Turt. Conch. Dict., p. 168.
KELLIA RUBRA. Turt. Brit. Biv., pp. 57 & 258, pl. 11, figs. 7, 8, 1822.
— — Flem. Brit. An., p. 430, 1828.
— — Gould. Inv. Massach., p. 60, 1841.
—_— _ Thorpe. Brit. Mar. Conch., p. 51, 1844.
— _ Alder. Cat. Moll. North. and Durh., p. 94, 1848.
_— —_ Ford. and Hanl. Hist. Brit. Moll., vol. ii, p. 94, pl. 36, figs. 5—7, and
pl. O, fig. 3, 1849.
Las#A RUBRA. Brown. Illust. Conch. Gr. Brit., pl. 20, figs. 18, 19, 1827.
Bornta sEMINULUM. Phil. En. Moll. Sic., vol. i, p. 14, pl. 1, fig. 16.
— ~ Desh. Exped. Scient. Algerie. Moll., pl. 43, figs. 8—11, and pl. 43 A,
figs. 6, 8.
Poronta RUBRA. Recluz. Rev. Cuy. Zool., p. 175, 1843.
co — Hanley in Brit. Mar. Conch. Syst. Ind., p. xxv, 1844.

Spec. Char. Testa minutd, ovata, tumidd, subinequilaterah levigata, utrinque rotundatd,

umbonibus prominulis.
Shell small, ovate, tumid, slightly inequilateral, smooth; both sides rounded,
umbones rather prominent.
Diameter, -1;th of an inch.
Locality. Coralline Crag, Sutton.
Recent, Mediteranean, Britain, North America.
A single slightly injured specimen from the rich Depot of small shells in the
Coralline Crag at Sutton is all that I have been able to obtain; it seems to have the
essential characters of the recent species, to which it is here referred, and as such
is introduced as an identity, although a few more and better specimens would be
desirable for confirmation: the character in which the preceding species seems most
to differ from the recent shell, and upon which its specific separation was founded, is
its being more inequilateral, and among all my numerous specimens there may be
observed a very general uniformity in that respect. The specimen now under notice has
the hinge more in the centre, placed as in the recent shell, the two lateral teeth forming
a very obtuse angle with the umbo; they appear rather less in size than those of the
British specimens, and these are said to be less developed than in the Mediterranean shell.
This is said by Mr. Clark (Mag. Nat. Hist., 1849,) to be the most terrestial of
Bivalves, its habitat being generally in Lichina pygmea, and that often from ten to
twenty feet above the level of the highest spring-tides.

126 MOLLUSCA FROM THE CRAG.

Monracuta. Turton, 1822.

LicuLa (sp.). Mont., 1808.

Prrricota (sp.). Gray, 1825.

Erycrna (sp.). Desh., 1825: (sp.) Myst, 1844.
MeEsopzsMa (sp.). Lovén, 1846.

Generic Character. Shell equivalve, inequilateral, transversely oblong, or obliquely
ovate, generally small and thin: surface smooth, or concentrically striated, and
occasionally with a few radiating ridges. Hinge with two diverging elongated teeth,
more conspicuous in one valve than in the other. Ligament internal, placed in a
triangular fossette: impression by the mantle without a sinus.

Animal oblong, having its mantle open in front, margins not fringed; without
siphonal tubes (?) ; foot large and broad, furnished with a byssal groove.

The name of this Genus was proposed in honour of Montague, the author of
‘Testacea Britannica;’ it is not, however, well determined, as two or three species,
the animals of which have undergone a careful examination, so far as their diminutive
forms will permit, seem to present considerable differences, and as far as regards the
shells alone, or their dental characters, the species here included would probably justify ©
their being separated into different Genera. As the authors of the ‘ Hist. of Brit.
Mollusca’ have made the same observation, and have not ventured to propose a new
Genus where the animals present characters so materially different, it would ill
become the Palzeontologist with only the shells to guide him, to venture upon such
a step.

Shells apparently of this Genus, at least such as present similar dental characters,
have been obtained from the Older Tertiaries of this country by Mr. Edwards; but
nothing as yet known have been found in any Deposit of a more ancient date. Its
Geographical range is at present limited to the European Seas and the Western Coast
of America.

1. Montacuta BIDENTATA, Montague. Tab. XII, fig. 17, a, 6.

Mya sBrpentTaTa. Mont. Test. Brit., p. 44, t. 26, fig. 5, 1803.
—_ — Mat. and Rack. Linn. Trans., vol, viii, p. 41, 1807.
— — Turt. Conch. Dict., p. 102, 1819.
MonracuTa BIDENTATA. Turt. Brit. Biv., p. 60, 1822.
— — Gould. Inv. Massach., p. 59, 1841.
_— — Macgill. Moll. Aberd., p. 302, 1843.
a — Thorpe. Brit. Mar. Conch., p. 52, fig. 58, 1844.
— — Alder, Cat. Moll. North. and Durh., p. 95, 1846.
_— — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 75, pl. 18, figs 6,
6a, 1849.
ANATINA BIDENTATA. Brown. Illust. Brit. Conch., pl. 11, figs. 8, 9, 1827.

BIVALVIA. 127

TELLIMYA BIDENTATA. Brown. Ilust. Brit. Conch., 2d ed, p. 107, pl. 44, figs. 8, 9.

PETRICOLA — Gray. Ann. of Philos., 1825.
— _— Hanley. Recent Shells, p. 54.
ERYCINA — Recluz. Rev. Zool., p. 331, 1844.

— FABA. WNysét. Coq. Foss. de Belg., p. 90, pl. 4, fig. 8, a—d, 1844.
MEsopEsMA ExIGuuM. JLovén. Ind. Moll. Scand., p. 42, 1846.

Spec. Char. Testdé minutd, oblongo-ovatd, inequilaterah, levigata, tenui; posticé ab-
breviatd, obtusé angulatd, anticé productd, rotundatd, vie attenuatd, margine ventral
et dorsal leviter arcuatis; dentibus duobus in utraque valvé; fovea lgamenti media
subumbone demissa.

Shell small, oblong or ovate, inequilateral, smooth, thin; posterior side short,
obtusely angulated, anterior produced and rounded, scarcely contracted; dorsal and
ventral margins slightly curved; two teeth in each valve ; a moderate sized cavity for
the ligament deeply situated beneath the umbo.

Length, §;ths of an inch. Height, 2ds the length.

Locality. Cor. Crag, Sutton and Gedgrave.

Red Crag, Walton Naze.
Recent, Britain, Scandinavia, and North America.

Specimens of this species are by no means rare in the Coralline Crag, and I have
found a few in the genuine Deposit of the Red Crag, at Walton Naze. Those from
the latter or newer Formation correspond precisely with the recent shell from our own
seas, and do not exceed it in size. The posterior side.is considerably the shorter of the
two, extending about one quarter the distance from the umbo that it does on the other
side: the shell is smooth or very nearly so, and moderately tumid, the anterior or
larger side forms half an ellipse, and the teeth are large and very distinct in the
right valve, the one on the anterior side being the longer; those in the left valve
are merely an angular elevation of the edge of the margin and inserted, when the
valves are closed, into the depression between the teeth and margin of the right or
opposite valve. The muscles are stated by M. Lovén to be large and powerful, but
the impressions left by them in my specimens are very ill-defined, and by no means
deeply seated.

In the recent state as a British species it is not very abundant, and is said by
British Conchologists to be generally found burrowing in very thick valves of dead
Oysters. I have never seen the fossil in such a situation.

2. MontacutTa TRUNCATA, S. Wood. Tab. XII, fig. 16, a, 4.

Montacuta TRUNCATA. S. Wood. Catalogue, 1840.

Spec. Char. Testaé valde inequilaterali, cuneiformi vel subrhomboided, compressa, con-
centricé striata; postice brevissimd, angulatd, antice productd, rotundatd, attenuate ;
margine ventrali et dorsali rectiusculis ; dentibus duobus divergentibus, in valud dewtrad
majoribus, foved ligamenti parva.

128 MOLLUSCA FROM THE CRAG.

Shell very inequilateral, subrhomboidal or slightly wedge-shaped, compressed
or flattened, covered with concentric striz; posterior side very short, angulated,
anterior produced, slightly contracted, and rounded ; ventral and dorsal margins nearly
straight ; two diverging teeth in each valve, much the larger in the right; a small
triangular ligamental cavity placed immediately beneath the umbo.

Length, 3ths. Height, ¢ of an inch.

Locality. Cor. Crag, Sutton.

This species is by no means scarce at Sutton, although valves of the above
dimensions are not very often met with.

There are differences in this shell that seem to justify a removal from the pre-
ceding, although it must be confessed it is very nearly related, and in the immature
state it is exceedingly difficult, if not impossible, to separate them, but what are con-
sidered to be the distinctive characters may be pointed out leaving to future obser-
vation to confirm or refute their identity.

In the recent species (4dentata), the shell is not only less in size but more
tumid, and nearly smooth, our fossil is compressed, and the body of the
shell much flattened, the posterior side is particularly short and truncate, sloping
direct fromthe umbo. On the anterior side, which constitutes nine tenths of the shell,
the dorsal and ventral margins are nearly straight but not quite parallel, the termi-
nation rounded and narrower, giving a somewhat cuneiform shape to the shell; the
exterior is covered with regular and large concentric strize or lines of growth, and the
ventral portion of the shell is slightly compressed, with an imperfect angular ridge on the
shorter side: the right valve has two large diverging teeth, the posterior one being
the smaller ; between these and immediately beneath the umbo is a small triangular
cavity for the ligament. In the left valve, the margin is elevated into angular
denticles which are inserted, when the valves are closed, between the margin and the
teeth of the opposite valve. Muscular impressions not very distinct.

3. Montacura susstTriata, Montague. Tab. XII, fig. 12, a, 6.
LicuLa susstriata. Mont. Test. Brit. Sup., p. 25, 1808.
Mya susstriata. Dillw. Desc. Cat. Rec. Shells, p. 47, 1817.
— — Turt. Conch, Dict., p. 103, 1819.
_ — W. Wood. Ind. Test., p. 11, No. 22, 1825.
Montacuta sussTriata. Turt. Brit. Biv., p. 59, t. 11, figs. 9, 10, 1822.
— — Flem. Brit. An., p. 465, 1828.
— — S. Wood, Catalogue, 1840.
_ — Macgill. Moll. Aberd., p. 303, 1843.
= _ Lovén. Ind. Moll. Scand., p. 43, 1846,
— —_ Alder, Cat. Moll. North. and Durh., p. 96, 1848.
a= — Forb. and Hanl. Hist. Brit. Moll., vol. i, p. 77, pl. 18, figs. 8,
8a, and pl, O, fig. 2, 1849.
TELLIMYA — Brown. Mlust. Brit. Conch., pl. 16, fig. 23, 1827.
ERycina — Recluz. Rev. Zool., p. 330, 1844.
SPHHNIA cosTuLaTA. Macgill. Moll. Aberd., p. 301, 1843, fide Ford. and Hani.

BIVALVIA. 129

Spec. Char. Testaé minutd, transversd, obliqud, ovatd, valdé inequilaterali, convexd,
politd, tenui, fragili ; antice productd, utrinque rotundatd ; costatd, costis acutis paucis ;
natibus prominulis ; dente cardinali unico.

Shell small, transverse, oblique, ovate, very inequilateral, convex, glossy, thin and
fragile ; anterior much the larger, both sides rounded; ornamented with a few small
sharp radiating ribs ; umbones rather prominent ; hinge with one tooth.

Length, -2;ths. Height, +th of an inch.

Locality. Cor. Crag, Sutton. Recent, Scandinavia and Britain.

This shell is by no means rare at the above locality. I have not yet seen it asa
fossil in any Formation of amore recent date. It appears toresemble in every respect
the living species, except perhaps it is a little larger. In order to institute a fair
comparison it may be thus more fully described. The posterior side is very short
and rounded, the anterior dorsal margin nearly straight, with a sharp and somewhat
prominent umbo. The shell is glossy externally, covered with radiating distant striz,
or rather small angular ridges, which extend all over the shell, but are most prominent
and conspicuous about the centre, and are more numerous on the older than on the
younger part of the shell, that is, they do not all terminate, or rather, originate at the
beaks; an intermediate ray is occasionally introduced on the body of the shell, but
on the anterior slope ten or a dozen of these ridges are interposed between two which
proceed direct from the umbo: hinge with a tooth in the right valve, placed in the
direction of the dorsal margin anteriorly, having a depression on the upper side of it,
and a similarly formed tooth, with a corresponding cavity in the opposite valve;
ligamental pit moderately large, sloping obliquely beneath the posterior dorsal margin.
In most of my specimens a slight depression is visible on the exterior, formed by the
contraction of the ventral margin, probably the result of a protruded byssus.

It is considered in the recent state a deep-water animal, ranging from 10 to 140
Fathoms.

4. MoNTACUTA FERRUGINOSA, Montague. Tab. XII, fig. 14, a, 6.
Mya FeRRuGINOSA. Mont. Test. Brit., Sup., pp. 22 & 166, t. 26, fig. 2, 1808.
Montacuta FERRUGINOSA. Turt. Brit. Biv., p. 60, 1822.
— _ Alder. Cat. Moll. North. and Durh., p. 96, 1848.
= — Forb, and Hanl. Hist. Brit. Moll., vol. ii, p. 72, pl. 18,
figs. 5, 5a, 56, 1849.
oo — dider. Ann. and Mag. Nat. Hist., 2d Series, vol. v, p. 210,
pl. 6, B, 1850.
—_ opLonGa. Turt. Brit. Biv., p. 61, t. 11, figs. 11, 12, 1822.
— — Flem. Brit. An., p. 465, 1828.
— — Thorpe. Brit. Mar. Conch., p. 52, 1844.
— — Macgill. Moll. Aberd., p. 302, 1843.
— GLABRA. Jlacgill. Moll. Aberd., p. 303, 1843.
—_— —_— Thorpe. Brit. Mar. Conch., p. 245, 1844.

17

130 MOLLUSCA FROM THE CRAG.

MonrTacuTa FERRUGINEA. Thorpe. Brit. Mar. Conch., p. 52, fig. 16, 1844.
ovata. S. Wood. Catalogue, 1840.
— TENELLA? Lovén. Ind. Moll. Scand., p. 43, 1846,

TrLLImyA ovata. Brown. Illust. Brit. Conch., pl. 14, figs. 20, 21, 1827.
—_ ELLIPTICA. Id. - - - pl. 14, figs. 17,18, 3,
_— GLABRA. yee : = 2d ed., p. 107, pl. 42, figs. 20, 21.
—_ ovata. Smith. Mem. Wern. Soc., vol. viii, p. 41, 1838.

ERYCINA FERRUGINOSA. Reeluz. Rev. Zool. Cuvy., p. 332, 1844.

Spec. Char. Testé transversd, ellipticd, convead, tenwi, levigatd vel concentricé striata ;
anticé longiore, posticé subattenuatd ; margine dorsali et ventrali leviter arcuatis.

Shell transverse, elliptical, convex, thin, smooth, or striated concentrically,
anterior side the longer, posterior slightly attenuated, dorsal and ventral margins
gently curved.

Length, 4 an inch. Height, ¢ of an inch.

Locality. Cor. Crag, Sutton. Recent, Britain and Scandinavia.

This is not an abundant shell in my Cabinet, a few specimens however are
sufficiently perfect to be fairly compared with the recent British shell, and I believe
the differences are not more than may be considered as local variations.

Our shell is very transverse, having a length about twice that of its height,
the anterior side occupying about three fifths of the entire shell; the posterior
side is rather more pointed than in the recent specimens I have compared with,
but in Messrs. Forbes and Hanley’s description of the livig species, it seems
to have a considerable range in variation, occasionally resembling our own shell
in that character, which appears to be its only difference: in perfect specimens
the exterior is covered with regular concentric striz, and the hinge is formed of an
internal ligament of an angular form, deeply inserted, and sloping towards the pos-
terior side; a portion of the ligament was probably seen externally, as a small sinus
is formed in the umbo, through which it might have extruded, this pit, or support
for the ligament is thickened at the edges, and elevated behind, so as to produce a
sort of denticle in the left valve, and immediately before it is a distinct though not a
prominent tooth, the same appearances are exhibited in the right valve, in which the
tooth is rather more elevated. ‘There are large adductor muscle marks of an ovate
form, and the impression by the mantle is entire.

The animal of this species has been recently examined by Mr. Alder, who has
published his observations in the ‘Ann. and Mag. of Nat. Hist.’ for the present year,
where he has pointed outa peculiarity in the mantle on the anterior side, by which it
appears, he says, to connect the open-lobed form in Zepéon with the anterior tubular
extension of that organ in Kellia.

Very extraordinary forms are assumed by the fleshy covering or eae im many
of the animals of this group, presenting us with distinctions so apparently anomalous
as to entitle them, if distinguished by that organ alone, to be removed to very distant

BIVALVIA. 13]

positions, but an evident relationship exists between their shelly exteriors, to separate
which would be a violation to any natural arrangement.

5. Montacuta? ponactna, S. Wood. Tab. XI, fig. 3, a—c.
Monracura? ponactna. 8. Wood. Cat. of Crag Shells, Ann. and Mag. Nat. Hist., 1840.
— ? CYLINDRICA, var. Id.

Spec. Char. Testd minutd, transversd, donaciformi, compressa, valdé inequilaterali,
laevigata ; posticé brevissimd, margine dorsali rectiusculd, margine ventrali convewiusculd ;
cardine edentula ? foved ligamenti profunda, obliqud.

Shell small, transverse, compressed, wedge-shaped, very inequilateral, smooth ;
posterior side very short, dorsal margin on the anterior side, nearly straight, ventral
margin convex; hinge without teeth? ligamental area oblique and deep, inclining
backwards.

Length, t. Height, 2;ths of an inch.

Var. cylindrica. Length, +th. Height, 3;th of an inch.

Locality. Cor. Crag, Sutton.

Three or four specimens only of this curious shell have been many years in my
Cabinet, but nothing like it, either recent or fossil, has fallen under my observation,
by which it can be even generically associated, although it appears very closely
allied to this or to the Genus Kellia. My two forms therefore are placed here
provisionally, with the best figures and descriptions their unfavorable condition will
permit, in order to call the attention of future Collectors to their existence.

Figure (4) represents the left valve, which is very flat, and very inequilateral ;
the posterior side being rounded, and scarcely extending beyond the umbo; nearly
the whole of the shell is on the anterior side, the dorsal margin of which is nearly
straight, but sloping a little from the umbo, the ventral margin convex, becoming
narrower at the anterior side, giving a wedge-shaped form to the outline of the
shell by having a greater height from the ventral margin direct to the umbo; in
the var. 6. (fig. @) also a left valve, it is not so; the posterior side being there
rounded, but not higher than any other part of the shell, and having such difference
only in the outline, I imagine it to be merely a variation, as in all its other characters
there is a specific resemblance. In an imperfect specimen of the right valve are two
small prominences of the edge of the shell, one on each side of the ligamental area,
scarcely deserving the designation of teeth, but perhaps a specimen in a better state
of preservation might have them more developed. The ligament is wholly internal.
placed immediately beneath the umbo in an angularly formed pit, inclining on the pos-
terior side. The exterior is smooth and glossy, with the lines of growth scarcely

visible.

132 MOLLUSCA FROM THE CRAG.

Cyamium.* Philippi, 1845.

Cyamium? Lovén, 1846.
Turtonta? Hanley, 1849.

Generic Character. Shell ovate, equivalve, inequilateral, closed, small, and thin:
externally free from ornament. Hinge with two cardinal teeth. Palleal impression
entire. Ligament internal.

This genus has been proposed for a species found in the Antarctic Seas, with an
internal ligament, and was adopted by Dr. Lovén for the little shell called Mya
purpurea by Montague, which has however been erected into a genus by the Authors
of the ‘ Hist. of Brit. Moll.’ under the name of Zurtonia, in consequence of its having
an external ligament.

CyAaMiuM? ExiImiuM, 8S. Wood. Tab. XI, fig. 5, a, 6.

Spee. Char. Testé minima, ovatd, transversd, inequilaterali, levigatd, tenui ; posticé
longiore, utrinque rotundatd ; cardine bidentato, uno laterali remoto pone ligamentum ;
apicibus prominentibus.

Shell small, ovate, transverse, inequilateral, smooth and thin; posterior side the
larger, both sides rounded. Hinge with two cardinal teeth, and one remote lateral
tooth behind the ligament; umbones prominent.

Length, 4th. Height, ;th of an inch.

Locality. Coralline Crag, Sutton.

One specimen of a species that appears to possess characters most in accordance
with the diagnosis of this Genus, is in my Cabinet, and I am induced to place it
here provisionally until some more shall be found, either to establish its right to
the position, or to remove it; the desire that everything found in the Crag should
be brought under notice must be advanced as an apology for the introduction of some
few imperfect materials here, as well as elsewhere, in this Monograph.

Our shell has an undoubted right to be specifically removed from d/ya purpurea,
Mont., though in some of its characters there is a resemblance. The specimen
figured is the left valve; it has two distinct, rather prominent, soft teeth close to the
umbo on the anterior side of the ligament, one standing at right angles to the length
of the shell, and the other, a larger one, diverging towards the anterior side, with
a sufficient space between them for the insertion of a tooth which the opposite valve is
supposed to possess: behind these teeth is a depression, where it is presumed the
ligament was placed, and if it were so, it must have been wholly internal, and invisible

* Etym. Kuaduoy, a little bean.

BIVALVIA. 133

when the valves were closed: behind this ligamental area is a large and somewhat
prominent tooth, which may be called a posterior lateral tooth within the dorsal margin,
and there is a depression outside of it, such as would receive a corresponding elevation
on the edge of the right valve: the posterior side of the shell is the larger, the dorsal
margin of which slopes with a gentle and elegant curve from a rather prominent
umbo, having a rounded extremity, and a gentle convexity in the ventral margin :
the anterior side slopes from the umbo with a straighter line, and is also rounded.
The shell is very thin and fragile, and was probably, when living, a semi-transparent
species. ‘The muscle marks are wholly invisible.

CrypTopvon.* Turton, 1822.

Tuyatira. Id. MS., 1819, fide Jeffreys. Axinus. J. Sowerby, 1821.
THIATISA. Id. MS., 1819, fide Gray. — Lovén, 1846.

Brquanta. Id. MS., fide Brown. . Prycuina. Phil., 1836.

Venus (sp.). Don., 1801. | Turatyra. G. B. Sow., Jr., 1842.

Tuyasira. Leach, MS., 1818, fide Lam. | TELLINA (sp.). Mont., 1803.
|
|

Generic Character. Shell equivalved, subequilateral, tumid, thin, subhyaline, and
closed: hinge with a single obtuse, or somewhat obscure tooth in each valve;
no lateral teeth. Ligament semi-internal, placed in a linear depression beneath the
dorsal margin: impressions of the adductor muscles indistinct, that by the ane
without a sinus.

Animal with an open mantle, but no prolonged siphons, foot long, subcylindrical,
and tubular, with a clavate extremity.

The Authors of the ‘ Hist. of Brit. Moll.’ have included this in the Genus Bits
but the animal of the one species that has been examined, appears to present
differences sufficient to entitle it to Generic distinction, and the characters of the
shell are so decidedly dissimilar, that a separation seems to be required.

There are several claimants for the honour of distinguishing this as a Genus,
and the strict right of priority is somewhat difficult to determine. Leach, in his
indiscriminate establishment of Genera, proposed several names, some of which were
put in print, and he may perhaps be the one most justly entitled. The name by
Sowerby has scarcely a better claim, as merely the exterior of the shell has been
observed, and the position of the ligament not clearly indicated, as Turton is next in
chronological order, his name is here employed.

Species strictly belonging to this genus have not been described from any
Formation of an older date than the Tertiaries, the shell called Axinus obscurus, from
the Magnesian Limestone, belongs to a different group, and has already been made
a genus of by Professor King, under the name of Schizodus.

* Etym. Kpvzrw, hidden, ddvvs, a tooth.

134 MOLLUSCA FROM THE CRAG.

1. Crypropon sinuosuM, Donovan. Tab. XII, fig. 20, a, 0.
Venus stnvosa. Don. Brit. Shells, t. 42, fig. 2, 1801.
TeLuina FLEXUOSA. Mont. Test. Brit., p. 72, 1803.
— — Mat. and Rack. Linn. Trans., vol. viii, p. 56, 1807.
= — Turt. Conch. Dict., p. 177, 1819.
se a W. Wood. Ind. Test., p. 22, pl. 4, fig. 78, 1825.
AMPHIDESMA FLEXUOSA. Lam. Hist. Nat. des An. s. Vert., t. v, p. 492, 1818.
TuyastIRa FLEXUOSA. ‘“ Leach, MS.,” Lam. Loc. cit. Sup., t. v, p. 492, 1818.
Lucina sinuaTa. Lam. Loc. cit., t. v, p. 543, 1818.
_ — Brown. Mlust. Brit. Conch., pl. 17, figs. 4, 6, 1827.
— sinuosa. Forbes. Report on Augean Invert., p. 182, 1843.
— — Thorpe. Brit. Mar. Conch., p. 74, 1844.
— FiExvosa. Flem. Brit. Ann., p. 442, 1828.
— — Gould. Invert. Massach., p. 71, fig. 52, 1841.
— — Ford. and Hanl, Hist. Brit. Moll., vol. ii, p. 54, pl. 35, fig. 4, 1849.
— — Reeve. Conch. Icon. Luctna, pl. xi, fig. 62.
— Sars. Id. - - - pl. ix, fig. 52.
— GoopHatit. J. Sow. Geol. Trans., 2d Ser., vol. v, pl. 8, fig. 7, 1834.
CRYPTODON FLEXUOsUM. Turt. Brit. Biv., p. 121, pl. 7, figs. 9, 10, 1822.
— — Brown. Mlust. Brit. Conch., 2d ed., pl. 39, figs. 4, 5.
- — Miller. Ind. Moll. Groenl., p. 20, 1842.
— — Alder. Cat. Moll. North. and Durh., p. 91, 1847.
_ BISINUATUM. S. Wood. Catalogue, 1840.
Prycutna BrpiicaTa. Phil. En. Moll. Sic., vol. i, p. 15, t. 2, fig. 4, 1836.
AXINUS UNIcARINATUS. Nyst. Rech. Coq. Foss. d’Anv., p. 6, pl. 1, fig. 22, 1835.
— Benepentt. De Koninck. Des. Coq. Foss. Arg. Boom, p. 35, pl. 11, figs. 2, 3,
1837.
— aNneuLatus. Nyst (not Sowerby). Coq. Foss. de Belg., p. 141, pl. 6, fig. 13, 1844.
~ — Michel. Desc. des Terr. Mioc. de l’Ital. Septen. (Haarlem Trans.),
p. 118, pl. 4, figs. 23, 23*, 1847.
— Fuiexuosus. Lovén. Ind. Moll. Scand., p. 38, 1846.
— Sarsit. Id. - - =) PasSyivey

Spec. Char. Testé ovato-orbiculari vel subhexagond, levigatd, tenui, subpellucidd,
tumidd, subequilatera ; latere postico biplicato, margine ventrali producto, lunulé cordato-
ovatd, magna, impress.

Shell ovately orbicular, with an irregularly hexagonal outline, smooth, thin and
subpellucid, tumid, and nearly equilateral; posterior side with two folds or furrows,
ventral margin produced, and a large and deeply impressed heart-shaped lunule.

Diameter, 5 an inch.

Locality. Cor. Crag, Sutton.

Recent, Augean Sea, Britain, Scandmavia, and North America.

This species is not at all abundant. There is no doubt of its identity with the recent
British shell, and I have given it as an inhabitant of the North West Coast of
America, upon the authority of that accurate observer, Dr. Gould. A specimen

BIVALVIA. 135

obligingly presented to me by Professor E. Forbes, obtained by him in the Agean
Sea, does not offer the slightest difference that could be considered as specific.

The recent shell is nearly transparent in its young state, becoming a little
thickened when full grown, and then only the true form of the muscular impressions
can be observed, that upon the anterior side is somewhat elongated, and within the
mantle mark, but has not the band-like form of the true Zwcima: the exterior is
smooth, with the exception of rather rough lines of growth, and in the centre of the
shell there is somewhat of a flattened space, which gives one side of a hexagon to
the ventral margin, there are two distinct depressions or sinuses on the posterior
side, and the dorsal margin of the shell is produced so as almost to cover over the
ligament, which might otherwise be called external, as it acts over a small fulcrum,
and opens the valve by its contraction; there is one obtuse tooth in the right valve
at the anterior termination, or rather commencement of the ligament, with a
corresponding depression in the left valve, and the umbo curves a little towards the
anterior, over its large and deep lunule.

Axinus angulatus of ‘Min. Conch.’ T. 315, is decidedly different, but the older
Tertiary shell “ Lucena Goodhallii”’ from Hampstead, appears so strongly to resemble
our species, that I cannot consider their triflmg differences to be more than the result
of locality, or of other conditions, and in examining many specimens of this shell
in the rich Cabinets of my friends, Messrs. Edwards and Wetherell, I could come
to no other conclusion, though all the specimens yet obtained have the two valves
so closely united, that their external characters alone are visible. The principal
difference appears to be in a rather more rounded outline to the older shell, which
has also less deeply produced folds or sinuses on the posterior side, but in the
examination of a specimen from Boom, in the Cabinet of Sir Charles Lyell, these
posterior sinuses were more strongly marked than in our Crag shell, with a rather
larger and deeper lunule, while the specimen itself exceeded in magnitude any of
my own, and judging from the figure and description of the Scandinavian shell 4zinus
Sarsi, Lovén, it does not appear to vary sufficiently to be considered specifically distinct.

It is quoted by Nyst as a fossil from Bordeaux.

2. CRYPTODON FERRUGINOSUM, Fordes. Tab. XII, fig. 19, a, 0.
CryPTopON RoTUNDATUM. S. Wood. Catalogue, 1840.
Ke.ira rerruGinosa. Forbes. Agean Invert. Rep. Brit. Assoc., p. 192, 1843.

ARTEMIS? = — Jeffreys. Aun. Nat. Hist., vol. xix, p. 313.

CLAUSINA — Id, - - - vol, xx, p. 18.
— ABYSSICOLA. Id. - - - - p. 18:
— Crovuinensis. Id. - - - - p. 19.

Luctna FeRRUGINOSA. Ford. and Hanl. Hist. Brit. Moll., vol. ii, p. 60, pl. 34, fig. 1, 1849.

;
A

Spec. Char. Testé minimd, rotundato-ovatd, obliqua, subequilaterali, tumidd, levigata,
tenui, fragili ; latere postico obsolete uniplicato ; dente cardinali unico, obtuso.

136 MOLLUSCA FROM THE CRAG.

Shell small, roundedly ovate, oblique, subequilateral, tumid, smooth, thin, and
fragile ; posterior side with one obsolete fold or furrow, one obtuse cardinal tooth.

Diameter, 4th of an inch.

Locality. Coralline Crag, Sutton. Recent, North Britain, and Augean Sea.

This is not an abundant fossil, and I have only met with it in the rich Depot
at Sutton.

When my Catalogue was compiled this species had not been recognised in the
recent state, and the name then proposed for it being without description, or anything
by which it could be identified, must give way to the subsequent one of Professor
Forbes. In comparing our fossil with the specimens now obtained in the British Seas,
no essential difference can be detected, and there is little doubt of their identity, and
when it is considered that the recent shell has been separated into three distinct
species, more than ordinary range in variation may be expected; the fossil is,
~ however, free from the ferruginous covering which obscures some of the characters of
the living shell; the Authors of the ‘Hist. of Brit. Moll.’ after uniting the three
species of Mr. Jeffreys, describe their shell as entirely without a fold, but in the most
perfect specimens of our fossil may be seen-an obscure inflection upon the posterior
side, which is here considered to constitute one of its most determinable characters,
and has always been in my Cabinet under the MS. name of Cryptodon, from that
resemblance. In the few specimens that I possess no great variation is observable ;
the general form is obliquely orbicular, the diameter rather greater when measuring
from the umbo to the ventral margin than from the anterior to the posterior side,
and in some specimens the outline shows a decided pentangular form. There is one
obscure tooth in each valve, like that in the preceding species, and the ligament is
placed in a depression beneath the dorsal margin, so that it must have been nearly
hidden when the valves were united; the anterior muscle mark is large, and of
an ovate form, and not band-like as in Zuciza. This shell has much the aspect of
Kelhia, and might, without much violence to classical arrangement, be placed there,
or at least, judging from the characters of the shell alone, it appears to have a
nearer relationship to that genus than to Lucina. In the living state it has only
been met with as a deep-water shell, both from the A‘gean and the North British
Seas, ranging from 20 to 100 fathoms.

Loripses,* Poli, 1791.

Loripes—LorrropERMA. Poli.
TELLINA (sp.). Linn.
AMPHIDESMA (sp.). Lam., 1818.
Tuiatisa (sp.). Leach, Nae Gray.
Liauta. Menke, 1830,

Uneutina. Bosc., 1802.

Taras? MRisso., 1826.

* Etym. Lorum, a strap, and pes, a foot.

' BIVALVIA. 137

Generic Character.—Shell orbicular, subequilateral, equivalve, lenticular; smooth
or striated externally. Hinge with one or two cardinal and two lateral teeth; the
latter sometimes obsolete. Muscular impressions unequal, anterior one the longer,
mantle mark without a sinus. Ligament internal.

Animal of the form of the shell, mantle open in front, with the margins crenulated ;
foot subcylindrical, crooked, club-shaped at the extremity, one siphon.

Although the animal is closely allied to Zwcina, it appears to be entitled to
generic distinction, on account of the difference of position in regard to the liga-
ment, being wholly internal, whereas in the other it is placed externally upon a ledge
or fulcrum; the reported difference in the siphonal opening is also an additional
reason for the separation.

This is a recent genus, and its age, as far as it is known to me, does not extend
beyond the Middle Tertiaries.

1. Loripes pivaricata, Linneus. Tab. XII, fig. 4 a, 6.
TELLINA DIVARICATA. Linn. Syst. Nat., ed. 12, p. 1120, No. 70, 1767.
— — ? W. Wood. Ind. Test., p. 23, pl. 4, fig. 87, 1825.
— oiqiTarIA. Poli. Test. utri. Sic., vol. i, p. 47, t. 15, fig. 15, 1791.
CaRDIUM aRcUATUM. Mont. Test. Brit., p. 85, pl. 3, fig. 2, 1803.
— _ Mat. and Rack. Linn. Trans., vol. viii, p. 67, 1807.
Luctna arcuata. Flem. Brit. An., p. 442, 1828.
— — Reeve. Conch. Icon. Lucina, pl. 11, fig. 61.
— opivaricata. Woodward. Geol. of Norf., p. 43 (not reference).
= — Galeotti. Mém. de Acad. Roy. de Brux., t. xii, p. 157, No. 137,
pl. 3, fig. 18, 1835.
== — Forb. and Hanl. Hist. Brit. Moll., vol. ii, p. 52, pl. 35, fig. 3, 1849.
— mrIFrarta. Krynecki. Bull. des Nat. de Mosc., p. 62, No. 11, 1837. Sec. Midd.
— commutata. Phil. En. Moll. Sic., vol. i, p. 32, t. 3, fig. 15, 1836.
— — Forbes. Rep. Mgean Invert., p. 182, 1843.
— — Middendorff. Malacozool. Ross., p. 566, (Mém. de l’Acad. des Sci.
de St. Petersb., 1849.)
— N.S. allied to pivartcata. G. Sow. and S. Wood. Mag. Nat. Hist., vol. iii,
p. 325, 1839.
Loripes unpuLARIA. 8S. Wood. Catalogue, 1840.

Spec. Char. Testa orbiculari, subequilaterali, convexd, bifariam oblique striata, divari-
cata, cardine dentibus lateralibus munito ; margine minutissme crenulata.

Shell orbicular, nearly equilateral, ornamented with oblique divaricating striz ;
hinge furnished with lateral teeth, and the margin very finely crenulated.

Diameter, ¥ an inch nearly.

Locality. Red Crag, Sutton.

Mam. Crag, Bramerton. Recent, Mediterranean, Britain.

This species appears first in the Red Crag, where it is very scarce, but I believe it

is rather more plentiful in the Mam. Crag, though not very abundant there: as a
18

138 MOLLUSCA’ FROM THE CRAG. :

recent British shell it is one of our rarest species. In a comparison with Montague’s
specimen, now in the British Museum, I was not able to detect the slightest
difference.

Our shell may be further described as very nearly orbicular, though in some
specimens, from a slight prominence of the umbo, the diameter is rather greater in
height: the hinge is furnished with one rather obtuse and angular tooth in the right
valve, and two lateral teeth, the posterior one is the more distant ; in the left valve are
two diverging cardinal teeth, with two lateral indentations corresponding to the teeth of
the opposite valve, and the ligament is placed behind the cardinal teeth in an oblique
fossette : the adductor muscle marks are slightly unequal: the anterior one is somewhat
elongated, but it has not the band-like form of the true Zucina: that by the mantle
is quite entire: the interior is often furnished with numerous radiating strie, and the
margin in very perfect specimens is finely crenulated. The exterior is ornamented
with diverging or divaricating striz, or rather ledges varying from 25 to 30, they are
slightly undulatory and have the ledge or elevated part on the upper side or towards
the umbo, and, are crossed by the lines of growth: the divergence is from an imagi-
nary line a little on the anterior side, at an angle generally of about 100°.

This is the only species with these peculiar markings that I have seen: the shell

from the Older Tertiaries, which is abundant in the Hordwell Cliff, has the ligament
placed wholly externally upon a projecting fulcrum, and the species from Bordeaux,
with the same specific name, differs in the like character, as also do the West Indian
shells. )
There are, probably, several species possessing these diverging and curving
radiations, all of which have been united under the name of divaricata, and a long
extension of Geological Age, as well as a wide Geographical distribution, have been
given in consequence. The common West India shell, and the Older Tertiary fossils,
also belong to the true Lucina.

Lucina,* Bruguiére, 1792.

VENUS (sp.). Linn.

TELLINA (sp.). Moné., 1803.

Cyracu@a. Leach, MS., 1819, fide Gray.
Myrrea. Turt., 1822. ‘

Puacoipts. Blainv., 1825.

Ortyetra (sp.). Brown, 1827.

Generic Character. Shell equivalve, generally equilateral, lenticular, compressed,
occasionally tumid; surface more or less ornamented with concentric striz or
elevated ridges, sometimes with radiating striz or coste. Hinge usually with two
diverging cardinal teeth in each valve, and two lateral teeth, which in some species

* Etym. A Proper Name.

BIVALVIA. — . ; 139

become obsolete: anterior muscular impression of a. ligulate or elongated form.
Palleal impression without a sinus. Ligament external.

The animal of this genus is described as having its mantle open in front, and
fimbriated edges ; very short siphonal tubes, with a long cylindrically-formed foot.

The genus as here restricted is intended to include all those species which have
an external ligament, of which the Venus borealis of Linneeus ‘may be considered the
type. This appears to form a distinct group, characterised by a differently formed
anterior muscle, which the mantle seems to envelope, and the impression is isolated
within: the edge of the mantle extending up to the anterior part of the adductor,
and not on the posterior edge where the line of the mantle mark, in most of the
Dimyaria, connects the two muscles.

1. Lucina BoREALIS, Linneus. Tab. XII, fig. 1 a, 4.
Vents BorzaLts. Linn. Syst. Nat., ed. 12, p. 1134, No. 143, 1767.
— — Don. Brit. Shells, vol. iv, t. 130, 1803.
— EXOLETA HQUILATERA. Chem. Conch. Cab., t. vii, p. 22, t. 38, fig. 406, 1784.
— spuRIA. Gmel. Syst. Nat., p. 3284, No. 72, 1788.
— — Dillw. Desc. Cat. Rec. Shells, p. 194, 1817.
— crrctnata? Broce. Conch. Foss. Subap., p. 552, t. 14, fig. 6, 1814.
JELLINA RADULA. Mont. Test. Brit., p. 68, 1803.
—_ — W. Wood. Ind. Test., p. 21, pl. 4, fig. 71, 1825.
Lucina RADULA. Turt. Brit. Biv., p. 116, 1822.
— —_ Phil. En. Moll. Sic., p. 35, t. 3, fig. 17, 1836.
— — Gould. Invert. Massach., p. 69, 1841.
— — Maegill. Moll. Aberd., p. 255, 1843.
— _ Dekay. Nat. Hist. New York Zool., pl. 26, fig. 274, 1843.
— aba. Turt. Brit. Biv., p. 114, t. 7, figs. 6, 7, 1822.
— antiauata. J. Sow. Min. Conch., t. 557, fig. 2, 1827.
— — Woodward. Geol. of Norf., p. 43, 1833.
— — Nyst. Coq. Foss. de Belg., p. 128, pl. 6, fig. 7, a, 6, 1844.
— conrracta? Say. Journ. Acad. Nat. Sc., vol. iv, p. 145, pl. 10, fig. 8.
— — ? Conrad. Am. Mioc. Foss., p. 40, pl. 20, fig. 5, 1838.
— Fianprica. WNyst. Coq. Foss. de Belg., p. 127, pl. 6; fig. 6, a, 6, 1844.
— sornaLis. Lovén. Ind. Moll. Scand., p. 38, 1846.
— Alder. Cat. Moll. North. and Durh., p. 91, 1848.
— — Ford. and Hanl. Hist. Brit. Moll., vol. ii, p. 46, pl. 35, fig. 5, and
pl. M, fig. 6, 1849.
— mitis. Woodward (not Sow.). Geol. of Norf., p. 43, 1833.

Spec. Char. Testd orbiculari, lenticulari, compressiusculd ; striis concentricis nume-
rosis, erectis, approximatis vel distantibus ; anticé rotundatd, posticé subquadratd, lunuld
lanceolata, cardine bidentato.

Shell orbicular, lenticular, somewhat compressed, covered with numerous con-
centric, erect strie or ridges, close or distant: anterior side rounded, posterior of a
squarish outline, lunule small, elongate, hinge with two cardinal teeth.

140 MOLLUSCA FROM THE CRAG.

Diameter, 1Zths of an inch.
Locality. Cor. Crag, Sutton, Ramsholt, Sudbourn, and Gedgrave.
Red Crag, Passim.
Mam. Crag, Postwick and Thorpe.
Recent, Mediterranean, Britain, Scandinavia, and North America.

This is one of our most abundant shells in the Coralline as well as in the
Red Crag.

In the young state, it is rather less equilateral than in the adult, and has
comparatively a larger and deeper lunule, with the teeth more distinct and prominent.
It is nearly orbicular, though sometimes there is a trifling difference in the dimensions,
the diameter from the anterior to the posterior side exceeding that from the umbo to
the ventral margin, and vice versé. In the right valve are two cardinal teeth, one
large and bifid, the other small and simple, with a prominent lateral tooth on the
anterior side, and in the left are also two cardinal teeth, one simple and the other
bifid, but their positions are reversed, the bifid one in the left being the anterior, with
a corresponding lateral tooth on that side. The interior is often strongly marked with
radiating strize, most distinct beyond the edge of the mantle mark : there are two deep
impressions by the adductor muscles, the posterior of an ovate form, the anterior one is
much elongated, being as it were bipartite, that nearest the anterior lateral tooth of
the usual form, with a ligulate prolongation down to near the middle of the shell; in
addition to which, in the interior about the centre is a banded impression extending
half way across the shell, in a direction at right angles to the ligamental fulcrum, as
if the mantle had there a division. In some specimens, the exterior is covered with
close-set lamellated striz, and the shell is somewhat tumid, while in others the shell is
flat or much compressed, and the concentric markings distant. A little inflection is
always to be seen on the posterior side, producing a more or less distinctly marked
sinus, and both sides are generally a little elevated, giving the shell the appearance of
being high-shouldered. A small but distinct lunule is visible, curving strongly near
the umbo, which gives to the young shell a comparatively larger mark there than
when it is full grown. ‘This shell is said in the recent state to have a range from
low water-mark to the depth of 90 fathoms.

2. Lucina CRENULATA, S. Wood. Tab. XII, fig. 7 a, 4.
Luctina crENULATA. S. Wood. Catalogue, 1840.
— srriatuLa? Nyst. Rech. Coq. Foss. de Hoesselt et Kl. Sp., p. 5, No. 11, pl. 1,
fig. 11, 1836.
o — ? WNyst. Coq. Foss. Belg., p. 131, pl. 6, fig. 9, a—e, 1844.
— oeENTata? Goldf. Pet. Germ., vol. ii, p. 230, t. 147, fig. 1.
— CRENULATA. Conrad. Amer. Mioc. Foss., p. 39, pl. 20, fig. 2.

Spec. Char. Testa parva orbiculari, equilateral, convexd, concentricé striatd, striis

numerosis confertis, lunuld impressd, elongato-ovatd ; dentibus lateralibus distinctis; margine
crenulata.

BIVALVIA. 141

Shell small orbicular, equilateral, convex, concentrically striated, strize close-set,
and numerous ; an ovate impressed lunule ; lateral teeth distinct; margin crenulated.

Diameter, + of an inch.

Locality. Coralline Crag, Sutton.

This species is exceedingly abundant, but restricted, as far as I have seen, to one
locality, where, from the prominence of the lateral teeth, the valves are sometimes
found united.

Our shell is furnished with one cardinal, obtuse, triangularly formed tooth in the
right valve, and a distinct and distant lateral tooth on each side: in the left valve
are two cardinal diverging teeth, with a triangular space between them, also two
lateral teeth: anterior muscle mark large, but not very narrow. The striz upon
the exterior are rounded, and about as broad as the spaces between them, and
the posterior side is marked with an obscure ridge, produced by a slight inflection of
the margin on that side, and at the ridge the strie often bifurcate, being less
numerous upon the inflected portion.

A shell in my Cabinet from Bordeaux, which I presume to be Lucina dentata, Bast.,
appears to differ from the Crag shell in several characters, it is more tumid, rather
wider in a contrary direction to our shell, and is more finely striated externally,
and has not so distinct a ridge on the posterior side; the anterior tooth is the
more prominent in our shell, and the inside has fine radiating striae, which I do
not observe in Basterot’s species; in ours the ligament is wholly external, placed
on a prominent fulcrum; in the Bordeaux shell it is internal, placed obliquely beneath
the umbo, and if I am right in the species, belongs to the genus Loripes.

Lucina striatula, Nyst, may possibly be the same as our shell, though it is distinctly
stated by that author to have the margin free from crenulations, but, judging from the
locality, his shel] may perhaps belong to the older or Bordeaux species.

From the description and figure of the American fossil by Conrad, I presume his
shell to be the same species. We have seen the preceding (Jorealis) to have a range
from the Mediterranean to the Coast of the United States, and there is great proba-
bility that the fossil from the Upper Tertiaries of that side of the Atlantic is identical
with our own; it is somewhat singular the author should have chosen for his shell
the same name under which the Crag species had passed in my Catalogue, and the
coincidence is perhaps the more remarkable, the American fossil having been obtained
from Suffolk, in Virginia.

3. Lucina pecorata, S. Wood. Tab. XII, fig. 6 a, 6.
Lucrna sauamosa? Goldf. Pet. Germ., vol. ii, p- 230, t. 147, fig. 3, a, 6.

Spec. Char. Testé transversd, ovatd, inequilaterali, crassa, striis radiantibus, et
decussantibus ornatd ; lunuld magné, lanceolata ; cardine unidentato, dentibus lateralibus
perspicuis : umbonibus prominentibus.

142 MOLLUSCA FROM THE CRAG.

Shell transverse, ovate, inequilateral, thick, and strong ; ornamented with radiating
strie, decussated by concentric ridges; a large elongated lunule; hinge with one
cardinal tooth and two lateral teeth in each valve: umbones prominent.

Length, + of an inch. Hezght, =3;ths of an inch.

Locality. Cor. Crag, Sutton.

This is by no means an abundant shell, and the above dimensions are to the
full amount of my largest specimen.

It is a pretty species, covered externally with large obtuse rays, or depressed ribs,
they are but few in number in the young state, increasing as the shell enlarges by the
introduction of an intermediate ray, sometimes diverging in pairs; they are crossed
by large obtuse ridges, or thickened lines of growth, placed sometimes in pairs,
generally more irregular; the shell is nearly oval, but the anterior side is much the
larger of the two, the umbo is elevated, and immediately beneath it is one triangular,
sub-bifid tooth in the right valve, with two distinct, nearly equidistant lateral teeth,
and in the left valve are two, diverging on each side of the triangular space, for
the reception of the one of the right valve, with two lateral teeth: the rays are
visible within the shell, and the muscle marks are not very deeply seated: the
anterior one is elongated, though not strictly of that ligulate or tongue-shaped
form so characteristic of the true Lucina. Tellina reticulata, Poli. (Lucina pecten,
Phil., ‘En Moll. Sic.,’ p. 31, T. 3, fig. 14), slightly resembles our shell, but it has finer
and more numerous rays, and is more orbicular.

Some time since I sent over to M. Deshayes a few specimens of three or four
species, thought to bear a very close resemblance to those of the Paris basin,
requesting he would be kind enough to compare them with his own types ; and since
the first part of my MS. had gone to press, I have received a communication from that
gentleman, who has obligingly complied with my request. He says: “J’ai examiné
avec la plus grande attention vos trois espéces Lucina squamosa, Erycina miliaria, and
Nucula miliaris, avec les types qui me’ restait dans ma collection et il resulte pour moi
de cet examen répété un grand nombre de fois, qu’aucune de vos espéces n’est
parfaitment identique avec celles de notre bassin Parisien. Ces espéces et les
notres ont entre elles de grandes resemblances mes elles offrent aussi des differences
constantes.”

The means of determination possessed by M. Deshayes are probably sufficient
to enable him justly to separate the Crag shell from the Older Tertiary species, and
I have given a new name to our fossil upon such decision; and in consequence of the
above opinion so strongly expressed, I have re-examined my own Crag specimens of
Nucinella miliaris with what I have considered as the same species from the Paris
basin in my own Cabinet, but with a high respect for the opinion of that able naturalist,
I cannot reconcile myself to the belief, that the differences observable between the two
are sufficiently prominent to justify a specific removal for the British fossil.

BIVALVIA. 143

DOUBTFUL.

4. LucCINA COLUMBELLA, Lamarch.
Lucina COLUMBELLA, Lam. Hist. des An. s. Vert., t. v, p. 543, No. 15, 1818.
— — Basterot. Mém. Geol. des Env. de Bord., p. 86, pl. 5, fig. 11, 1825.
— — Bronn. Letheea Geogn., p. 959, t. 37, fig. 15, a—d, 1837.
meet) py — Dujard. Mém. de la Soc. Geol. de France, tom. ii, pt. 2, p. 258,
1887.
_ _— Dubois de Mont. Foss de Wolhyn., p. 57, pl. 6, figs. 8—11, 1831.
— — G. B. Sowerby. Genera of Shells, No. 27, fig. 6.
— — Phil. En. Moll. Sic., vol. ii, p. 26, 1844.
— — Reeve. Conch. Icon. Luctna, pl. 6, fig. 30.
— VULNERATA. De France, sec. Basterot.

Three specimens of this species are among the Red Crag Fossils in the Wood-
wardian Museum at Cambridge; and as it will be seen by the above references, it
was an inhabitant of the Seas which deposited the Bordeaux Beds, found also in the
Faluns of Touraine, in the Plateau Wolhyni-Podolien, and according to Philippi, has
been obtained at Sortino, in the Val di Noto, it is very possible it may have had
an extension into the Red Crag, more especially as .a shell resembling this (probably
only a variety) is still a living species on the N. W. Coast of Africa.

No satisfactory information respecting these so called Red Crag specimens could,
however, be given by any of the gentlemen connected with the Cambridge Museum,
although Professor Sedgwick says he believes them to be true Crag shells, but being
myself unable thoroughly to examine their lithological character, and never having
seen the same species in any other Collection of Crag Fossils, and in the absence of all
knowledge of their correct locality, they must, at least for the present, be considered
as not strictly entitled to a place in the undoubted Fauna of that Period.

Diptoponta,* Broun. 1831.

TELLINA (sp.). Mont., 1803.

Myst (sp.). Leach, MS.,1819. Brown, 1827.
Venus (sp.). Broce. Nyst.

Lucina (sp.). Def. Desh.

Dietoponta. Bronn., 1831.

SpHmReLLA? Conrad, 1838.

Generic Character. Shell somewhat thin, more or less orbicular, equivalve sub-
equilateral, externally smooth, or slightly marked by lines of growth, umbones not
very prominent. Hinge composed of two cardinal teeth in each valve, the anterior
one in the right valve simple, the other bifid, and the reverse in the left, no lateral

* Etym. ArwAdos, double, ddous, a tooth.

144 MOLLUSCA FROM THE CRAG.

teeth. Ligament external, no lunule. Impressions by the adductors ovate; mantle
mark without a sinus.

Animal of the form of the shell, with its mantle closed all round, except in front,
through which a lanceolate-shaped foot is protruded: margin of the mantle with
plain edges. Siphons are said to be wholly wanting.

Our recent British species has been examined by Mr. Clark, who has pointed out
an apparent anomaly by which it differs from the generality of Dimyaria, in being
wholly destitute of anything resembling siphonal tubes, and without an orifice, except
the pedal one, he says, for the admission of water to sustain the functions of life.

Its position among the Lwcimde is at present considered doubtful by the
Malacologists, in consequence of this anomalous character in regard to the mantle;
the shell, however, so strongly resembles many of the species of this group, that
no other position seems so appropriate.

1. DipLoponTA ROTUNDATA, Montague. Tab. XII, fig. 3 a, 4.
TELLINA ROTUNDATA. Mont. Test. Brit., p. 70, t. 2, fig. 3, 1803.
— — Mat. and Rack. Linn. Trans., vol. viii, p. 56, 1807.
_ — W. Wood. Ind. Test., p. 22, pl. 4, fig. 77, 1825.
Mysia rotunDaTA. Brown. Illust. Brit. Conch., pl. 16, fig. 11, 1827.
= — Id. Conch. Text. Book, p. 132, pl. 17, fig. 6, 1837.
— Monraeur. Leach, MS., fide Brown.
Lucina RotunDATA. Turt. Brit. Biv., p. 114, pl. 7, fig. 3, 1822.
— —, Thorpe. Brit. Mar. Conch., p. 73, 1844.
— — Forbes. Report on Mgean Invert., p. 180, 1843.
= — Brown. Brit. Conch., 2d ed., pl. 40, fig. 11.
— — Reeve. Conch. Icon. Lucina, pl. vii, fig. 36.
PsAMMOBIA ROTUNDATA. lem. Brit. An., p. 438, 1828.
DreLtoponTa RotuNDATA. PAil. En. Moll. Sic., vol. ii, p. 24, 1844.
— — Forb. and Hanl. Hist. Brit. Moll., vol. 11, p. 66, pl. 35, fig. 6,
and pl. M, fig. 7, 1849, ©

Spec. Char. Testé suborbiculari vel trapezoidea, inequilaterah, posticé latiore et

longiore, subquadratd, anticé rotundatd ; apicibus prominulis ; margine dorsal feré rec-
tilineo: cardine bidentato.

Shell suborbicular, or of a roundedly trapezoidal form, inequilateral, posterior side
the longer, broader, and somewhat square, anterior rounded, with slightly prominent
umbones: dorsal margin nearly straight: hinge with two teeth.

Length, \3th of an inch.

Locality. Coralline Crag, Sutton, Ramsholt, Sudbourn, Gedgrave.

Red Crag, Sutton. Recent, Mediterranean, and British Seas.

This is a shell exceedingly abundant in the Coralline Crag, where specimens
may be obtained from nearly 14 inch in diameter to those which are less than 3th
of an inch. In the Red Crag it is also found, but less abundantly. The hinge in

BIVALVIA. 145

both valves is furnished with two teeth, one simple, the other bifid, the simple one is
placed before the umbo in the right valve, and the bifid one is anterior in the left,
while the ligament occupies a position wholly external, and is deeply inserted :
the muscle marks are large and well impressed, of an oblong form, with the mantle
mark entire: numerous fine radiating striz are often visible in the interior, like some
of the Lucine, the outside is what may be called smooth, having only the irregular
lines of increase. The shell is somewhat flattened, though occasionally tumid, more
especially on the posterior side.

I have followed Philippi in assigning the Mediterranean shell to this species, as
he has done in his second volume, the figure in the first volume more resembles the
next species, for which it was taken when my Catalogue was compiled.

2. DirpLoponta piLatata, S. Wood. Tab. XII, fig. a, d.
DrpLoponta piLatTata. S. Wood. Catalogue, 1840,
_ — ? Nyst. Coq. Foss. de Belg., p. 138, pl. 7, fig. 1, 1844.
== — J. Sow., in Dixon. Geol. and Foss. of the Tert. and Cret. Form.
of Sussex, p. 167, t. 3, fig. 16, 1850.
Venus Fracitis? Myst and West. Nouv. Rech. Coq. Foss. d’Anv., p. 9, pl. 3, fig. 11.

Spec. Char. Testd transversd, ovatd, inflatd, inequilaterali, tenui, posticée longiore
utringue convexd ; margine dorsali rotundato ; apicibus obtusis, depressis.

Shell transversely ovate, tumid, inequilateral, thin, posterior side the larger, both
sides convex ; dorsal margin rounded ; umbones obtuse, depressed.

Length, #ths. Height, 3ths of an inch.

Locality. Coralline Crag, Sutton, and Gedgrave. Red Crag, Sutton.

This species is not at all abundant. There are about a dozen specimens in my
Cabinet presenting characters that appear of sufficient prominence to entitle it to be
considered as different from the preceding one, and a few more particulars may therefore
be pointed out to support the opinion. Our shell is more regularly rounded on both
sides, and has not the squareness of outline so conspicuously shown in that species,
where the dorsal margin forms a straight line, giving a distinct angle on the posterior
side, whereas in this one it is eminently rounded, and the whole shell is more regularly
tumid ; the posterior side is considerably the larger, and the umbones are rather
depressed, turning a little towards the anterior, and the ligamental area is smaller than
in the preceding species ; the shell is thin, and the muscle marks not very well defined,
but where they are seen, they appear to be different in size, the posterior one being the
longer, and of a rounded oblong form, and that by the mantle without the least inflec-
tion: the teeth are two in each valve, one simple, the other bifid, the posterior one
is simple in the left valve, in the right it is anterior; the bifid one is less, and the single
one is better defined than in the preceding species ; the whole aspect of the shell is also
different, that I have no hesitation in separating the two. This species and rotundata

19

146 MOLLUSCA FROM THE CRAG.

are found in the same locality, and I have one specimen from the Red Crag in good
preservation, exhibiting the same distinction. The figure by Nyst more strongly resem-
bles this species than the last one, so also does that by Philippi. The latter author states
his shell to be living in the Red Sea, thus giving a greater probability to its being
different from the one living in the British Seas ; a few specimens of apparently the same
species from the Older Tertiaries at Bracklesham are in the Cabinet of Mr. Edwards,
one of which has been figured in Mr. Dixon’s work above referred to. In comparing
them with the Crag specimens some trifling differences may be observed, but, they
do not appear of sufficient importance for specific distinction, and the Crag shell is in
all probability the prolonged existence of the Bracklesham fossil. In dental characters
they are precisely the same, but the Crag shell is rather more tumid, and it is also a little
longer, the dorsal margin being somewhat less rounded than in the older shell, and the
exteriors of the Crag specimens have merely fine and somewhat irregular lines of growth,
while the Bracklesham fossil has rather more regular concentric striz, they however both
present sufficient distinction to justify a separation from the recent British species.

3. DIPLODONTA? ASTARTEA, WVyst. Tab. XII, fig. 2, a, 6.
TELLINA asTaARTEA. Nyst. Rech. Coq. Foss. d’Anv., p. 5, pl. 1, fig. 18, 1835.
Luctna GyraTa. S. Wood. Catalogue, 1840.
— asTaRTEA. Nyst. Coq. Foss. de Belg., p. 121, pl. 6, fig. 4, 1844.
Mys1a Americana? Conrad. Foss. Shells of the Med. Tert. United States, p. 30, pl.16, fig. 2.
DipLtoponta parvuLa? Nyst. Coq. Foss. de Belg., p. 139, pl. 7, fig. 2, 1844.

Spec. Char. Testd obliqud, ovato-obiculari, depressiusculd, inequilaterali ; in senec-
tute intus spissatd ; posticé majiore, anticé subangulatd ; dente cardinal bifido.

Shell oblique, ovately orbicular, somewhat depressed, inequilateral, inside of
specimens thickened; posterior side the larger, anterior subangulated: cardinal tooth
bifid: no lunule.

Diameter, #ths of an inch.

Locality. Cor. Crag, Sutton. Red Crag, Sutton.

This shell is very abundant in the Red Crag, but it is rather scarce at one locality,
from the Older Formaiton of the Coralline Crag, and presents some slight differences,
though not sufficient to remove it from the species.

Our shell measures three quarters of an inch from the anterior to the posterior
side, and about the same or a trifle less from the umbo to the ventral margin, these
proportions are occasionally reversed, but there is in general not much variation
in this species: it is somewhat oblique, and measures rather more from the dorsal edge
or position of the ligament to the opposite margin than ina contrary direction, although,
in the young shell, it is the reverse; the umbones are prominent, the hinge has one simple
and one bifid tooth in each valve, the surface is marked with somewhat irregular lines of
growth at considerable distances. The interior in the adult shell is much thickened,

BIVALVIA. 147

as in some of the species of Lucima, showing the muscle marks deeply impressed ;
they are nearly equal in size, though the anterior one is rather narrower, the line
of the mantle is without the least inflection: in the thickening of the interior a
ridge is produced near the upper anterior margin, giving the appearance of an addi-
tional muscle mark; a similar appearance may be seen in the old specimens from
the Coralline Crag, besides an obscure ridge running down the centre dividing it
into two nearly equal parts. There is no doubt of this species being identical with
the Belgian fossil, and according to M. Nyst, it is said to have been found in the
Older Tertiaries from the environs of Paris. I have not seen it from the Mam. Crag.

D. apicalis, Phil., somewhat resembles the young of our shell, but it appears to
have a greater comparative height from the umbo to the margin; and I have been
unable to see a specimen of this or of D. ¢rigonula, Bronn, which also does not very
greatly differ.

The dentition of this species precisely resembles that of D. rotundata, as well as
the muscle marks of the interior, from which it is presumed to belong to the same
genus, but the interior of aged specimens is thickened like those of Zwcina, to
which it appears to be very closely related. The specimen figured has a somewhat
sinuated form in the margin on the posterior side, which is merely accidental ; it was
selected for the purpose of showing the interior.

Lucinopsis, Forbes and Hanley, 1849.

Mysta. ‘Leach,’ Lam.,1818. King, 183-2? 8S. Wood, 1840.
Venus (sp). Penn. Mont. Flem. Phil. Lovén.

Lucina (sp.). Turt. Lam.

CytHErea (sp.) Macegill, 1843.

ARTEMIS (sp.). Alder, 1847. Recluz.

Dosinta (sp.). Gray, 1847.

Generis Character. “Shell more or less orbicular, rather thin, equivalve, slightly
inequilateral, closed; surface smooth or concentrically striated, inner margin entire ;
muscular impressions oblong or suborbicular, nearly equal. Palleal sinus wide, deep,
central, obtuse. Hinge composed of two diverging central teeth, one of which is
bifid in the right valve, and three, the central one bifid, in the left. Ligament
external, prominent, rather long. No defined lunule.”

* Animal suborbicular, its mantle freely open, the margins entire. Siphonal tubes
short, diverging, separate, the branchial with its orifice fringed, the anal simple.
Foot lanceolate. Labial paps, small, triangular.”

This being the first and only diagnosis of the genus I have seen, it is copied from
the authors of the ‘ Hist. of British Mollusca,’ whose name is here adopted.

The long and well-known British species Venus undata, of Pennant, is considered
as the type of the genus.

148 MOLLUSCA FROM THE CRAG.

It has been justly remarked, by Messrs. Forbes and Hanley, that in consequence
of its anomalous character, this shell has been bandied about and placed in many
different genera, but generally with a doubt respecting its true position; the deep
palleal sinus indicated the possession of somewhat elongated or at least projecting
siphons, thereby differing from the animals of true Zuwcina, in which genus some
authors had placed it, where from its dental characters and general appearance it
seemed most entitled to be situated. They have, however, removed it from among the
family Lucinide, and placed it in the Veneride, in consequence of the deeply sinuated
form of the palleal impression; and this view of its connection seems to have been
taken by other Malacologists.

The possession of a sinus in the impression of the mantle mark is a distinction,
we have elsewhere seen, in all probability sufficient for the removal of a shell with
such a character out of a genus, where others have the mantle mark perfectly entire,
but there is no sufficient reason in that alone that it should be removed to any very
distant position. Its general affinities appear more in connection with those of Lucina
than with those of Venus, differing from the former only in the aberrant character of a
prolongation in the siphonal tubes, bearing the same relationship to Lucina, or rather
to Diplodonta, that Leda does to Nucula, or as Adacna to Cardium : I have, therefore, again
ventured to remove it from among the Veneride to what appears a more correct position.

The name of J/ysia was proposed in MS. for a genus by Dr. Leach, in which the
Venus undata, Penn., was placed; and this name has been published by Lamarck in his
‘Hist. Nat. des An. sans Vert.,’ t. v, p. 543, 1818, thereby giving it a status in regard
to time; and considering that sufficient for its right to priority, it was adopted by
myself in ‘The Catal. of Crag Shells,’ for the Crag species, but another well-identified
shell belonging to the genus Dzplodonta had also attached to it the same generic
name, and this was published by Brown, in 1827. It is not now possible to say which
of the two species was intended as the type of his proposed new genus, and therefore,
to unravel the difficulty, or rather to cut the Gordian knot, the authors of ZLucinopsis
have, perhaps wisely, rejected in toto the name of A/ysia.

This appears a very natural genus, although very few species are yet known
either in a recent or fossil state. Two or three shells from the Greensand Formation,
figured and described under the name of THETIS, somewhat resemble it in the dental
characters, but they have a deeper and more angulated sinus in the mantle mark.

1, Luctnorsts Lasonxatrit, Payraudeau. Tab. XI, fig. 14, a—e.
Ency. Method., p. 272, fig. 2, a—é, 1800.
VenERuPIS LasonkarriI. Payr. Cat. Moll. del’Ile de Corse, p. 36, pl. 1, figs. 12, 13, 1826.
— — Desh. 2d ed. Lam., t. vi, p. 164, 1835.

VENUS LUPINOIDES. Nyst. Rech. Coq. Foss. Prov. d’Anv., pl. 11, No. 41, pl. 3, fig. 14.
Mysia ornata. S. Wood. Catalogue, 1840.

TELLINA LUPINOIDES. Nyst. Coq. Foss. de Bélg., p. 111, pl. 5, fig. 4, a—e, 1844.

— ? articutata. Td. : = - p. 110, pl.e6; figs 1,2, 8:

BIVALVIA. 149

Spec. Char. Testa tenui, orbiculari vel subpentangulari, viv equilaterali, tumidd, sub-
obliqué ; striis confertis, articulatis ; umbonibus prominulis, approximatis ; margine integro.

Shell thin, orbicular, or somewhat of a pentangular outline, scarcely equilateral,
tumid, and rather oblique; ornamented with numerous close-set articulated striz ;
beaks slightly prominent and close; margin smooth.

Diameter, 13th of an inch.

Locality. Cor. Crag, Ramsholt, and Sutton,

Red Crag, Sutton. Recent, Corsica and Sicily.

About a dozen specimens of this species in perfect condition have been obtained
by myself from the Coralline Crag at Ramsholt: a few with the valves united, and
one only from the Red Crag.

Not having been able to obtain a specimen of the recent shell for comparison, its
identification is dependent upon the figures and descriptions above referred to, but
its outward form and ornamented exterior are so peculiar, that it is assigned to the
Mediterranean species without much hesitation.

The hinge of the right valve is furnished with two primary diverging teeth, the
posterior one being bifid, while the left valve has three teeth ; the centre one of which
is large and double, or so deeply cleft, as to give that valve the appearance of having
four; there are no distinct lateral teeth, though on the anterior side the lateral edges
interlock; it has but an elongated fulcrum for the external ligament; there are no
lunule: the two large impressions by the adductors, the anterior one being the smaller
and more narrow ; the impression by the mantle is large, deep, and rounded, ascending
beyond the middle of the shell, and extending over to the anterior side. In outline
it much resembles LZ. wndata, and also in its very visible but somewhat irregular lines
of increase, but it differs in the possession of numerous radiating striez. The length
generally exceeds the height by about an eighth, but in some specimens there is no
difference.

Hippacus.* Jsaac Lea, 1833.
VerticorpiA. S. Wood, MSS., 1842.

Generic Character. ‘Shell cordate, inflated, without teeth ; beaks large, recurved,
margin slightly overwrapping beneath the beak: anterior cicatrix long, posterior
cicatrix round.”

The above is given by Lea in his ‘ Contributions to Geology,’ as the diagnosis of a
genus proposed to be established upon a small fossil shell found in the United States,
in a Formation of the Older Tertiary Period, and it has been adopted by Philippi, who
has included im it a fossil from the Valley of the River Lamati, in Calabria, and as this
appears to be identical with our Crag Species, I have followed the latter Author in the
generic assignment.

* Etym. Hippagus, a horse-ferry boat.

150 MOLLUSCA FROM THE CRAG.

1. Hippagus vERtTIcorpDIus, 8S. Wood, Tab. XII, fig. 18, a, 4.
Crypropon? verticorpiIA. S. Wood. Catalogue, 1840.
VERTICORDIA CARDIIFORMIS. S. Wood. MS., 1844.
— — J. Sowerby. Min. Conch., t. 639, 1844.
Hrpracus acuticostatus. Phil, En. Moll. Sic., vol. ii, p. 42, t. 14, fig. 19, 1844.

Spec. Char. Testé suborbiculari vel cordiformi, convexd, subequilaterali, tenui, costata
costis circa 16 incurvatis,. compressis, radiantibus, rugosis ; apicibus antrorsim involutis ;
margine denticulato.

Shell suborbicular, or heart-shaped convex, thin, subequilateral, costated, ribs about
16, incurved, radiating, compressed, rugose; apices involute; margin denticulated.

Diameter, ths of an inch.

Locality. Coralline Crag, Sutton.

This elegant shell is by no means abundant as a British fossil, and from the figure
and description above referred to, there is every reason to believe the same species
once inhabited the seas which deposited the Upper Tertiaries of Calabria. A slight
difference exists between our shells, as far as can be determined without an inspection
of the specimens, but such as does not appear to be more than a local variation, and
not sufficient to affect their specific identity.

The Italian fossil has given to it only 13 ribs, while there are 15 to 16 in our shell,
but like some species in the genus Cardium (which it resembles externally,) this may
be a variable character: the ribs are elevated, and laterally compressed, rounded on
the top, but not sharp or angular, as Philippi’s name would seem to imply, and as his
figure represents: they are elegantly curved, and are generally rugose, or coarsely
imbricated, and distributed at about equal distances; the concave spaces between them
are rather wider than the ribs themselves, and appear to be finely granulated, or studded
over with small papille. In the interior are the marks of two somewhat large
adductor muscles, the anterior one is the more deeply impressed, that by the mantle
is indistinct: the ligament or cartilage appears to have been placed so far within the
dorsal margin of the shell, that when the valves were closed it was probably not visible,
being placed in a depression beneath the margin, extending into a cylindrically formed
aperture towards the umbo, and the receding of the ligament, or its desertion on the
anterior side, causes a slight involution of the umbones, like that of Jsocardia, though
in a very minor degree. A callous, but prominent and obtuse tooth in the right
valve, close to the umbo, fits into a sinus in the left valve: the shell is beautifully
nacreous within, and though not particularly thin, the ribs are visibly marked in the
interior by deep indentations, and they project considerably beyond the margin, inter-
locking and serving the office of prominent denticles.

TAB. I.

Fig.

1. Ostrea Princeps, page 17.
a. inside view of lower valve.
4. outside ditto of upper valve.

2. Anomia aculeata, p. 9.
a. outside view of upper valve.
b. ditto ditto var. striolata.

3. Anomia ephippium, p. 8.
a. upper valve of a specimen of var. squamula, showing the radiating coste
produced by the animal adhermg to the umbonal region of a Pecten.
4. id., specimen formed on the central portion of a Pecten.
c. 1d., outside view of var. cylindrica.
d. the testaceous plug, or lapideous portion of the adductor muscle, commonly
called the operculum.

4. Anomia patelliformis, p. 10.
a. outside of upper valve.
b. ditto ditto var. undulata.

The lines indicate the size of the specimens.

TLAGB', PL es

George Sowerby

TAB. II.

Fig.
1. Ostrea edulis, page 13.
a. specimen with united valves.
6. outside of lower valve of var. sinuata.
e. specimen with united valves, var. spectrum.

2. Ostrea Princeps, p. 17.
a. outside of lower valve.
6. ditto of young specimen. .

3. Anomia striata, p. 11.
outside of upper or imperforate valve.

Li.

TAPS:

Sowerby

>

~
oh
Sa)

a.

Hinnites Cortesyi, page 19.

mart

LAB LE.

George Sowerby

TAB. IV.

Fig.
1. Pecten maximus, page 22.
a. outside of lower valve of var. vulgaris.
b. id., upper valve, var. complanatus.

2. Pecten Danicus, p. 30.

3. Pecten dubius, p. 38.

TABLE Va

1)
: Ku NOY

es

i

HAC

Ten =

x “A
Belen ure

George Sowerby

po por Weg

es
a Pom vo t 2 os
Roe . eee ~ ~
Pm ais ig ae ee bad mcalts oa Sasncie
Re ttre end “pe rae a

Bere
xle divergence of
Saaee

c. right valve.
5. Pecten Gerardi, p.24.
a. right valve. iN

left valve.

Vv

TAB

Sowerby

cveordge

TAB. VI.

Fig.
1. Pecten Princeps, page 31.

2. Pecten opercularis, p. 35.
a. left valve of var. lineatus.
b. id. var. reconditus.
C. id. var. scabrotus.
d. specimen with united valves, var Audouinii.

3. Pecten dubius, p. 38.
left valve of var. partim imbricatus.

4. Pecten pusio, 7p. 33.
a. specimen with united valves of var. striatus.
6. left valve, var. limatus.
c. right valve, var. striaturus.

5. Pecten gracilis, p. 37.

The lines indicate the size of the specimens.

Vi

TAB.

2a,

FFE Ter eh 1
ves teeery

Peary:

ae

OS
aS

3

sais | 2 GS 8 re mR

A ET
alll ff all!

Ne

Sean

RES

Si hl

HD,

Sower tn

Geoarge

Fig.
. Lima Loscombii, page 45.

TAB. VII.

. Lima hians, p. 44.

. Lima subauriculata, p. 47.

a. three views of specimen, natural size.

6. enlarged view of hinge line of young individual with minute
crenulations.

c. var. elongata.

. Lima plicatula, p. 46.

Small figure the natural size.

. Lima ovata, p. 48.

Small figure the natural size.

. Lima exilis, p. 43.

. Pecten maximus, var. grandis, p. 22.

a. lower valve.
6. upper valve.

TR 4
“i

FU a Ae

x 3
~ ‘
: :
te
:
.
-
.
: .
ad ¥
- : ,
>. r
. e ¥ .
,

Fig.
. Modiola modiolus, page 57.

“J

10.

Le.

TAB. VIII.

a. outside view of var. vulgaris.
6. inside ditto.
c. inside ditto, elongated var.

. Modiola barbata, p. 58.
. Modiola sericea, p. 61.

. Modiola phaseolina, p. 59.

c. inside view of young specimen, showing a crenulated margin.

. Modiola discors, p. 60.

. Modiola costulata, p. 60.

a. outside view of elongated var.
6. inside ditto var. Petagne.

. Modiola marmorata, p. 62.

. Modiola rhombea, p. 64.

Outside view of two varieties.

. Mytilus edulis, p. 52.

var. elegans.
5» antiquorum.
incurvatus.
», saxatilis.

OR, SS ces

, aleeformis.
Mytilus hesperianus, p. 55.

Pinna pectinata, p. 50.

The lines indicate the size of the specimens.

Tah. Va,

George Sowe rby

Fig.

TAB. IX.

1. Pectunculus glycimeris, page 66.

a.
b.
Bi

t.

outside view of transverse var.

inside ditto of ditto

hinge line of antiquated specimen, showing the obliteration of denticles
by the advance of the ligament.

-- outside of elongated var.

magnified view of the young shell showing one tooth only, on each side
of the dental area.
outside view of a young specimen, with distinct and elevated costz.

. hinge with full complement of teeth.
h,

inside view of var. subobliquus.
outside ditto of ditto.

2. Limopsis aurita, p. 70.

C.

var. A.

3. Limopsis pygmea, p. 71.
ce. hinge magnified.

Tab. IX,

\

Mt i sr ade
"uaa

Georde Sowerby.

Dei

Oe

2

pas

¥

_

TAB. X.

Fig.
1. Arca tetragona, page 76.

a, outside view of specimen from
Red Crag.

6. inside view of the same.

c. outside of abraded specimen,
with a sinuated form of ven-
tral margin (Bissoarca).

d. inside of var. Britannica.

2. Arca lactea, p. 78.
a. outside, left valve.
6. inside of the same.

3. Arca pectunculoides, p. 79.
a. outside of var. brevis.
6. inside of var. elongata.

4. Nucinella miliaris, p. 73.
a. inside of right valve.
6. inside of left valve.
e. united valves, showing the posi-
tion of the ligament.

On

. Nucula tenuis, 7. 84.

6. Nucula nucleus, p. 85.

Fig.
7. Nucula trigonula, p. 86.

8. Nucula levigata, p. 81.
9. Nucula Cobboldiz, p. 82.
10. Leda semistriata, p. 91.

11. Leda pygmea, p. 95.
a. inside view of an acuminated
specimen.
6. outside of a specimen of a
more rounded form.

12. Leda caudata, p. 92.
13. Leda pernula, p. 93.
14. Leda truncata, p. 94.
15. Leda Thracizformis, p. 96.

16. Leda lanceolata, p. 88.

17. Leda myalis, p. 90.
ce. outside view of elongated var.

The lines indicate the size of the specimens.

Tab: Xs

George Sowerby.

Fig.
. Pisidium amnicum, page 109.

a. inside of elongated specimen
from Stutton.

6. ditto of © var.
Grays.

sulcatum from

. Cyclas cornea, p. 107.

a. outside of var. tumida.
b. ditto of var. compressa.

. Montacuta donacina, p. 131.

6. inside of left valve.
c. outside of the same.
a. inside of var. cylindrica.

. Kellia cycladia, p. 122.
. Cyamium? eximium, 7. 132.

. Lepton depressum, p. 116.

. Lepton nitidum, p. 116.

8. Lepton squamosum, p. 114.

9.

Lepton deltoideum, p. 115.
c. hinge of left valve slightly
enlarged.

‘d. ditto —_— right valve-ditto.

» Kellia rubra, p. 125.

. Anodonta cygnea, p. 102.

. Unio littoralis, p. 98.

. Unio tumidus, p. 99.

. Lucinopsis Lajonkaimu, p. 149.

. Cyrena consobrina, p. 104.

c. specimen of a more trigonal
form.

The lines indicate the size of the specimens.

Tab. XT.

Uti Lee

George So M" erh V4

10.

TAB. XII.

. Lucina borealis, page 139.

. Diplodonta PEA # 146.

. Diplodonta rotundata, p. 144.
. Loripes divaricata, p. 137.

. Diplodonta dilatata, p. 145.

. Lucina decorata, p. 141.

. Lucina crenulata, p. 140.

. Kellia suborbicularis, p. 118.

a. orbicular variety, left valve.
6. transverse ditto, right valve.

. Kellia orbicularis, p. 120.

a, 6. interiors of both valves mag-
nified.
c. outside view, natural size.

Kellia coarctata, p. 123.

Fig.

11. Kellia ambigua, p. 120.
a. trigonal variety.
6. elliptical ditto.

12. Montacuta substriata, p. 128.

13. Kellia elliptica, p. 121.
6. united valves, showing the sinu-
ated form of hinge margin.

14. Montacuta ferruginosa, p. 129.
15. Kelha pumila, p. 124.

16. Montacuta truncata, p. 127.

17 : Montacuta bidentata, py. 126.
18. Hippagus verticordius, p. 150.
19. Cryptodon ferruginosum, p. 135.

20. Cryptodon sinuosum, p. 134.

The lines indicate the size of the specimens.

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POGORAPHICAL 2

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»

PALHONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVII.

LONDON:

~—

WPAID02 TAOTHIAOOTHOR IAT

i

MOMLOT

A MONOGRAPH

MOLLUSCA FROM THE GREAT OOLITE,

MINCHINHAMPTON

AND

THE COAST OF YORKSHIRE.

BY

J. MORRIS, F.G.S. ax> JOHN LYCETT.

Pate. 0

UNIVALVES.

LONDON :

PRINTED FOR THE PALAZONTOGRAPHICAL SOCIETY.
1850.

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orai

INTRODUCTION.

Tue authors of the present Monograph, after due consideration of the materials at
their disposal, have thought fit to limit their illustrations to the Testacea of the Great.
or Bath Oolite; a term under which they would include the series of beds situated
between the Fullers-earth strata upon which they repose, and the Bradford clay to which
they are subjacent. To have enlarged the plan, so as to include the Testacea of the Corn-
brash and Forest marble, would doubtless have been more comprehensive ; but in the
present state of our knowledge, the advantage would have been rather apparent than
real. It will be found that the very few univalves which have been assigned to
those deposits are almost without exception contained likewise in the Great Oolite, and
will be found in the Monograph. It is, moreover, not impossible, that at some future
time a series of univalves may be obtained from the Cornbrash, or Forest marble, differing
specifically from those of the Great Oolite, in which case a separate Monograph, or an
appendix to the present one, might be given.

It is much to be regretted, that collections of shells should have been procured
from so few situations in the long course of the formation m this country; and when
it is remembered, that the Great Oolite constitutes a member of that series of secondary
rocks which first engaged the attention of geologists, some surprise will mingle with
our regret. The defect, however, would appear to be of easy explanation. The shells
do not lie upon the surface, or become separated from the matrix by the action of
the weather; they are to be procured only by carefully working away the investing
stone when practicable, which is not always the case: there are likewise large areas
constituting, probably, the greater portion of the formation, which are altogether des-
titute of organic remains, or contain only a finely comminuted shelly drift; the areas
containing assemblages of well-preserved shells, would appear to be of small extent, and
the presence of several of these in the vicinity of the residence of one of the authors,
together with the great profusion of undescribed testacea which they have produced,
have constituted the principal inducement to the present attempt of describing them ;
these favorable circumstances have enabled them to ascertain the position and vertical
range of the species with a greater degree of accuracy than would otherwise have
been possible.

Beyond the limits of the Minchinhampton district, the number of species procured

i}

vi INTRODUCTION.

has been but inconsiderable ; these latter belong chiefly to Ancliff,‘ and to the vicinity of
Scarborough. The parallelism of the deposits at the two former places would appear
to be well ascertained, but with respect to the rocks which are so extensively exposed
upon the coast of Yorkshire, although the evidence of geological position appears to
be satisfactorily determined, they possess but few mineral features which serve to connect
them with their supposed equivalents in Gloucestershire, Wiltshire, and Somersetshire ;
they constitute a great carboniferous deposit of the Oolitic period, abounding with land
plants, and containing intercalated bands or thin beds of dark gray argillaceous shales,
limestones, and sandstones, containing marine shells, of which only a minority of species
have been identified in other localities. The evidence afforded by the few species of
univalves which have been forwarded to the authors from Scarborough, through the
kindness of Mr. Bean, though not conclusive, tends rather to assimilate them with the
Inferior Oolite ; and it will be perceived on consulting the table of species at the end of
the Monograph, that of the twenty-one Yorkshire species, none have been identified with
Great Oolite shells of Mmchinhampton or Ancliff, but that seven agree specifically with
Inferior Oolite shells of the Cotteswold hills. The Yorkshire deposits to which these
remarks refer constitute the entire series of plant-bearing beds numbered 11, 12, and 13
in Phillips’s ‘ Geology of Yorkshire,’ reposing on No. 14, or the Dogger, which is proved by
its fossils to be the equivalent of the Inferior Oolite, or at least to a portion of that
formation. Admitting, therefore, the parallelism of the deposits contaming somewhat
distinct Faunas, in the north-eastern and south-western parts of the present area of
England, we are naturally led to infer, either that the physical conditions might be favor-
able to the continuance of species in one locality, or that species characteristic of an older
deposit, in a more distant region, may have migrated and lived on during the formation of
a newer deposit im another, the conditions having become unfavorable to the perpetuity
of their development in the latter deposit over the original region whence they had
migrated,”

For the above-mentioned reasons, it has been deemed desirable to separate the

1 The section at Ancliff, near Bradford, is as follows :

Rubble . 5 feet. . . Abounding with Polyparia.

Soft Oolite15 .,, . . This is the bed celebrated for the Ancliff fossils.

Clay . 1,4, . . Containing small sponges, and many fragments of shells.
Rag - 63 .,, . . Very coarsely Oolitic.

Soft Oolite 5 ,,
From Mr. Lonsdale’s interesting memoir, ‘On the Oolitic District of Bath,’ in the ‘Geol. Trans.,’ vol. iu,
p. 252, in which many other sections of the Great Oolite are given, and the range of the deposit in that
neighbourhood is accurately traced.

? Unfoytunately the entire character of the fauna of the Great Oolite in the centre of England is not
well ascertained, nor is the range and extent, southerly, of the fluvio-marine conditions of the Yorkshire
Oolite accurately determined. As bearing on this point, the reader is referred to a paper by Captain
L. L. B. Ibbetson and Mr. Morris, “On the Geology of Stamford’’ (‘ Brit. Assoc. Rep.,’ 1847, p. 127).
The subject of migration of species, during the Oolitic epoch, is ably treated in a valuable memoir by
M. Gressly, ‘Observations Geologiques sur la Jura Soleurois.’

INTRODUCTION. vil

Yorkshire shells from those of the West of England, and to have them figured on separate
plates, as by this arrangement it is trusted that confusion will be avoided, whatever may
ultimately be determined with regard to the position of these deposits.

It will be observed that several characteristic groups of shells have been arranged
into new genera and sub-genera, the knowledge of which, it is believed, will conduce
materially to the identification of the members of the lower Oolitic system of rocks ; of
these Ceritella, Brachytrema, Alaria, Cylindrites, and Trochotoma, are likewise represented
in the Inferior Oolite, but by other species ; in no instance has any species of these genera
been found common to the two formations. Other genera occur whose species are equally
characteristic of the two formations; the table of comparison at the end of the memoir will
indeed serve to show how small a number of the spiral univalves are really common to both
formations ; with the Patelloidea the case is somewhat different, but the entire number,
excluding the Yorkshire species, is very small; a fact the more worthy of notice as a much
larger number of the bivalves are common to both, or if capable of being separated, can
only be regarded as sub-species, or varieties of the same species. ‘The literature of the
science has hitherto been singularly deficient in illustrations of English Great Oolite
univalves ; Lhwyd’s ‘ Lithophylacii Britannici Ichnographia’ contains a few ; Conybeare and
Phillips, in their ‘Geology of England and Wales,’ p. 210, enumerate three species.
Sowerby’s ‘ Mineral Conchology’ contains thirteen, one only of which is from the Min-
chinhampton district. Mr. Lonsdale’s paper on the ‘ Oolitic district of the neighbourhood
of Bath’ has only three identified species. In Prof. Phillips’s ‘ Geology of Yorkshire,’ (part
I, p. 123,) fifteen species of wnivalves are enumerated, which are reproduced in Mr.
Williamson’s paper on the ‘ Yorkshire Oolites,” but without descriptions. Dr. Fitton’s notice
of the strata at Stonesfield’ gives an accurate enumeration of the different beds, but with few
organic remains. In the paper by Capt. L. L. B. Ibbetson and Mr. Morris, on the
‘Geology of Stamford,” a few univalves are mentioned ; and, lastly, in the ‘ Geology of Chel-
tenham,’ edited by Messrs. Strickland and Buckman, a list is given from the Stonesfield
slate of Hast Gloucestershire of six Echinodermata, or at least fragments of them, and
nineteen gasteropoda, remains of which, however, are sometimes very imperfect.* It may be

‘Geol. Trans., 2d Ser., vol. v, Part i, p. 240. Zool. Journal, vol. iii.
3 Brit. Assoc. Reports, 1847.

* The following is a section of the quarry on Sevenhampton Common, whence most of the fossils were
obtained :

Soil . 5 5 « 2 feet.

A yellow clay, of a Aotiewhat soapy ‘feel, very rich i in fossil shells . 6 ,,

Ragstone, similar to the Stonesfield slate : -— ,, 4 inches.

Thin seam of soft stone, with Ostrea acuminata, and jaan joints of
Apiocrinites : : : =e, eon Ys:

Blue marl : : ‘ : Soe eas

Ragstone ‘ P A ‘ ; 4 es

Stonesfield slate ; ‘ : : 5 &

Fullers-earth

viii INTRODUCTION.

gathered from these details, that in undertaking the present work, the authors have neces-
sarily, toa great extent, entered upon an unexplored field of study,—have been compelled
to investigate the relations of forms which, in very many instances, have only recently been
brought under their notice, and respecting whose analogues some doubt or difference of
opinion may occasionally exist: with a sincere desire to avoid error, they have in every
instance rejected species of which the examples were imperfect or doubtful.

It is with pleasure and gratitude they acknowledge the assistance which they have
received in the prosecution of their task, and their thanks are especially due to Professor
Edward Forbes, for his valuable memoir on the Echinodermata; to D. Sharpe, Hsq., for his
copious notes on the Nerinez, and other valuable suggestions ; to Wm. Bean, Esq., of Scar-
borough ; to M. Bouchard, of Boulogne ; to Professor Tennant, F.G.S.; to S. V. Wood, Esq.,
F.G.8.; to Pro‘essor Buckman; to — Bravender, Hsq., of Cirencester ; and to J. Bentley,
Esq., of Stamford, for the loan of specimens for comparison and figuring: to M. A.
Buvignier, of Verdun, for his little work on the ‘ Oolitic Fossils of the Ardennes ;’—also
for the opportunities afforded them in consulting the important collections of the Viscomte
D’Archiac; J. Baber, Esq., F.G.S.; J. S. Bowerbank, Esq., F.R.S.; J. G. Lowe, Esq. of
Chippenham; Rev. P. B. Brodie, F.G.S.; E. H. Bunbury, Esq., M.P., F.G.S.; S. P.
Pratt, Esq., F.R.S.; and to Professor E. Deslongchamps, of Caen, for his obliging kindness
in forwarding to them a suite of specimens typical of some of the species figured by him
in a series of memoirs, containing many valuable observations, published in the seventh and
eighth volumes of the ‘Mémoires de la Société Linnéenne de Normandie ;’ as well as to
J. de Carle Sowerby, Esq., for the loan of many of the original specimens described in the
‘ Mineral Conchology ;’ and to G. R. Waterhouse, Esq., and S. P. Woodward, Esq., for the
facilities afforded to the authors in their examination of the species contained in the National
Collection. To the artists, Messrs. Bailey and C. R. Bone, of the Ordnance Geological
Survey, the authors tender their acknowledgments for the pains they have taken in the
general accuracy of the lithographs.

U

A MONOGRAPH

OF THE

MOLLUSCA FROM THE GREAT OOLITE.

GENERAL GEOLOGICAL REMARKS.

Tae Minchinhampton district of the Great Oolite has produced by far the greater
number of our illustrative specimens ; and as the formation at that locality exhibits features
of a very varied as well as comprehensive character, we may be excused for entering
somewhat more into detail in our remarks upon it. The Great Oolite in this portion of
Gloucestershire constitutes the uppermost rock of the Cotteswold Hills; it everywhere
overlies the Fullers-earth, which, in turn, reposes upon the uppermost beds of the Inferior
Oolite ;—there is, therefore, a regular unbroken sequence of the Oolite rocks exposed on
the flanks of the various deep valleys of denudation which pervade the district. The
physical features of the district are strongly marked ; the larger valleys have a mean depth
of about 500 feet, and exhibit what can scarcely be met with in any other part of England ;
a single unbroken declivity comprising the Great Oolite, Fullers-earth, Inferior Oolite, and
upper portion of the Lias. The Inferior Oolite at these escarpments has a thickness of about
230 feet, the Fullers-earth of 70 feet, and the different beds of Great Oolite of 120 feet ; but
of these latter, only about the lower 40 feet anywhere approach to the brow of the escarp-
ments. The narrow and deep vale of Chalford, with its lateral branches, intersects the
strike of the Great Oolite, and divides the fossiliferous portion of the district into two parts ;
another and wider valley, further south, likewise intersects the strike of the formation. In
this are situated the villages of Woodchester, Hailsworth, and Avening; but here the
amount of denudation, horizontally, has been more extensive; and as the Great Oolite is
likewise much less fossiliferous, it need only be adverted to as supplying many additional
positions, where the rock can conveniently be quarried by open-work excavations. It will,
therefore, be perceived that the natural features of the district eminently conduce to the
study of its organic remains.

2 MOLLUSCA FROM THE GREAT OOLITE.

The mineral masses which constitute this series of beds are exclusively of marine origin,
the varying character of their organic contents being connected both with the mineral
character of the deposit spread upon the floor of the ancient sea, and with its depth.
These deposits may be conveniently divided into three groups :

Ist. The Weatherstones ; 2d. The Sandstones ; and 3d. The Limestones.

The weatherstones, which are situated at the base of the formation, average about
40 feet in thickness. They consist of shelly sandstones, abounding with crystalline
carbonate of lime, and having Oolitic grains irregularly and sparingly distributed throughout
their mass. The variety of mineral character is so great, that no two quarries, or beds of
the same quarry, or even distant parts of the same bed, are alike in structure, aspect,
hardness, durability, or in the abundance of their included organic relics ; and they appear
to have constituted a deposit both littoral and formed in a shallow sea, exposed to the
influence-of tides and currents. The beds, which are sometimes of considerable thickness,
consist of layers of testacea, in a fragmentary state, piled confusedly, but forming, obliquely,
laminated surfaces, often interrupted and crossed by others which proceed in different
directions. The shelly relics often constitute a considerable proportion of the whole mass ;
they are converted into crystalline carbonate of lime, which frequently fills the interior of
the univalves; and it is to the abundance of this mineral, disseminated everywhere, that
the weatherstones owe their superior durability upon exposure to the atmosphere. Asa
general rule, therefore, the beds which contain the greatest abundance of shells are those
which are most fitted to resist the action of frost ; water percolates their structure in much
smaller quantity, and more slowly, and, on escaping, carries away but little lime in
solution. ‘The open joints of the Great Oolite, adjacent to the shelly beds, are therefore
nearly free from the large stalactitical masses which load the joints of the freestone in the
Inferior Oolite.' With the testaceous fragments are associated shells in a perfect condition,
though frequently worn and abraded, the valves of the conchifera being rarely in apposition ;
also, palatal bones and teeth of fishes, portions of crustacea, spines of cidaris, ossicula of
pentacrinites and asterias, rolled fragments of zoophytes, and dicotyledonous wood, the
partitions of the beds disclosing not unfrequently the ripple-marks of a beach. It might
be imagined that beds of such a littoral character would be unsuited to the propagation
and development of the Cephalopoda ; and it will occasion no surprise when we find that

1 For economic purposes, the weatherstones are valuable on account of their durability. In proof of
this, we may refer to the good state of preservation which the ancient part of the church at Minchinhampton
exhibits, and which shows a care and judgment in the selection of materials not always to be found in
modern edifices. It is rather a singular fact, that Caen and Minchinhampton, the two places which have
produced by far the most extensive series of Great Oolite shells, are connected historically as well as geologically.
Matilda, wife of William the Conqueror, founded the nuns of the Holy Trinity at Caen, of which body one
of her daughters became a member. William endowed them with the manor of Minchinhampton, at which
place they had a religious establishment. They built the church, and dedicated it to the Holy Trinity.
It would seem that William despoiled the Saxon Countess Goda of the manor, which she possessed in the
time of Edward the Confessor, and bestowed it upon the favorites of his wife.

MOLLUSCA FROM THE GREAT OOLITE. 3

examples of this class of carnivorous mollusks are here few, both as to number of species
and of individuals. ‘This fact, together with the circumstance that they do not mark any
particular stratum, renders it highly probable that they were not associated, when living,
with the denizens of these shelly beds, but, like dead shells of the recent Spirule,
individuals occasionally floated upon the surface, and were wafted to some coast or shelly
strand, often very distant from their real habitat. With the chambered shells such occur-
rences may have been common ; the air-tight little vessel, separated by decomposition from
the animal, would ride upon the wave, and only suffer injury upon striking the ground of
the beach. A consideration of the gregareous habits of the several families of recent, and
probably also of extinct Cephalopoda, would lead us to regard an occasional stray individual
as having travelled from some colony more or less distant ; but the beds of closely-packed
Ammonites, of every stage of growth, which occur in certain of the Jurassic rocks, would
appear to be the effect of occasional rapid earthy deposits, which took place during that
seasonal period when the Mollusks, lying torpid and contracted within their shells, were
at once entombed in that condition. We have also an explanation of the perfect condition
which the Ammonites of these beds usually exhibit; the place of retirement would be
exempt from the turbulence of a shallow sea, and exposed only to the deposit of mud or
other fine sediment, which would protect the shells from injury. In the few Ammonites
and Nautili of the weatherstone beds, we see the reverse of these conditions ;—those large
and fragile shells, exposed in that detrital deposit to every kind of attrition and accident,
are very rarely perfect; seldom more than two continuous chambers can be found which
have not been invaded by earthy sediment, and often large portions of shell are wanting
altogether. The paucity of the Brachiopoda in these beds is also worthy of notice. ‘Three
species of Terebratula are found associated with nearly 400 species of Mollusks; and
certain genera, which are peculiarly prominent in the Oolitic rocks generally, are mostly
absent ; of these genera, the Pholadomyze, Homomyz, Cercomyz, Myopsides, Gresslyz or
Pleuromye, the Arcomyz and Ceromyz, being exceedingly rare. The greater number of
these genera are not uncommon in the limestones or upper beds of the Great Oolite, and
occasionally, also, in the lower beds or sandstones, when they are separate from any shelly
deposit.

The section of the shelly beds, exhibited by the great quarry upon Minchinhampton
Common, affords a clear view of their distinctive characters and order of superposition.
The upper part consists of thinly-laminated stone, five or six feet in thickness ; to this
succeeds the beds usually termed planking, a designation implying a thin bedded stone,
out occasionally consisting of beds of great thickness: fourteen feet would appear to be
their utmost thickness. They mark the downward limit of our new genus Purpuroidea,
in the lowest bed of which it is very abundant.

An uncertain and variable stratum, of a few inches, of sandy marl next succeeds, in
which the few casts of bivalve shells hitherto found have the valves in apposition. To this
succeeds thin-bedded yellowish sandstones, nearly destitute of shells, and worthless for

4 MOLLUSCA FROM THE GREAT OOLITE.

economic purposes: their thickness is about twelve feet. A soft, shelly sandstone, called
oven-stone, next occurs: the shells increase in quantity downwards: about six feet will
represent its thickness. ‘To this succeeds the weatherstones, consisting of several beds, the
ageregate thickness of which is about six feet. These lower beds are very shelly ; but, owing
to the greater hardness of the matrix, specimens cannot be extracted in any considerable
number. ‘The blue or brown clays of the Fullers-earth support the weatherstones, without
any appearance of Stonesfield slate. It is also absent in several other limited shelly
deposits ; but, as a general rule, throughout the district, the Great Oolite, near to its base,
has one or more beds, which possess all the essential characters of Stonesfield slate. A little
higher in the series than the shelly beds, the limestones occur which cover continuously a
very considerable area upon both sides of the vale of Chalford, and continue upwards, with
various modifications of character, even to the Bradford clay. ‘The lowest of this series is
a very compact cream-coloured semi-siliceous, but argillaceous limestone, four feet thick,
divided into two beds. It is usually destitute of organic remains; but in some localities
contains casts of species of Purpuroidea, of several species of Natica; and, also, at a single
locality, a dense colony of our new genus Pachyrisma, which has not hitherto been found
in any other stratum. ‘This limestone extends even to the vicinity of Cirencester, and was
employed by the Romans to form tessare for their pavements, as noticed by Messrs.
Buckman and Newmarch, in their new work on Corinium.’ The base line of the white
limestone is 60 feet above the Fullers-earth at Minchinhampton, and 45 feet, four miles to
the east of that place, near to the railway (Sapperton tunnel); the measurements have
been obtained. by well-sinkings. Above this rock occurs a series of pale brown or
chocolate-coloured limestones, sometimes compact, sometimes sandy, having between them
an occasional uncertain band of marly clay. These clays are always fossiliferous, abounding
in casts of bivalve shells, which have both valves generally united. The uppermost 40 feet
of this series, owing to the worthless character of the stone, is very imperfectly exposed,
our knowledge of it being chiefly derived from pits of no great size, opened for the repair
of the roads. ‘The eastern extremity of the railway tunnel (Sapperton) offers an extensive
section of these beds, but their position does not allow of their being studied, except at a
distance. The white limestone is exposed about the middle of the section. One of the
road-side excavations, two miles east of Minchinhampton, and 90 feet above the Fullers-
earth, has two beds of sandy limestone which is more than usually fossiliferous, they
expose sections of Nerinea, Pterocera, Natica, Cylindrites, Bulla, Purpuroidea, several of
the Echinodermata, &c. The bivalves, which are more numerous, comprise Pholadomya,
Homomya, Ceromya, Lucina, and Cercomya. ‘The shell is preserved in the condition of
crystalline lime, but the interior mould only can be extracted entire. At three miles and
a half east of Minchinhampton, a large excavation has a band of brown clay, which abounds
with Zerebratula mazillata, being almost the only fossil. This band is 115 feet above the

1 «Tllustrations of the remains of Roman art in Cirencester, the site of Antient Corinium,’ by Professor
Buckman, F.G.S., and W. C. Newmarch. London, 1850.

MOLLUSCA FROM THE GREAT OOLITE. 5

Fullers-earth. In‘another direction, one mile south-east of the town, is a marly band,
containing a dense colony of a species of Terebratula, which is likewise the sole fossil
observed. ‘This isolation of the Terebratulz is worthy of notice; they occur but as a few
stray individuals in the shelly beds of the formation : in one instance, indeed, a shelly quarry
at Bussage, a little to the north of the vale of Chalford, contains a large assemblage of a
smooth, undescribed species, but at that place the other genera suddenly disappear, and the
Terebratule are either alone or accompanied only by a few small bivalve shells. The
Bradford clay, marked by the Terebratula digona, has not been discovered nearer than the
cuttings at the Tetbury road station, eight miles distant. The Great Oolite has now been
traced upwards throughout the Minchinhampton district, but there yet remains a sub-
division of the formation to be noticed ; this consists of sandstones, nearly worthless for
economic purposes, and of but little interest to the Palzontologist; they constitute the entire
series of beds which underlie the limestones, and usually terminate downwards in Stones-
field slate, or have one or two beds which approach the slate in mineral character. These
sandstones must be regarded as merely continuations of the Weatherstone beds, but are nearly
or quite destitute of shelly detritus and crystalline structure ; for it is a curious but un-
doubted fact that the shelly weatherstones never have the limestones incumbent upon them.
All the quarrymen are aware of the fact from the experience which they have gained in the
numerous trials for weatherstone. At Bussage an instance may be seen of a weatherstone
quarry passing into a worthless sandstone on approaching the area covered by the lime-
stone ; occasionally, indeed, the sandstones disclose a cluster of Pholadomye, and in the
vicinity of the Stonesfield slate contain some other bivalves which are never found in the
shelly beds. Occasionally over some small areas good serviceable quarries of weatherstone
are worked in situations where scarcely a single perfect shell can be procured ; there is then
a dense, finely comminuted, shelly detritus, and the rock abounds with calcareous spar, and
becomes thick bedded ; several quarries of this description have been worked in the parish
of Avening with good success ; in this condition the rock presents an exact counterpart to the
general aspect of the freestone beds in the middle portion of the Inferior Oolite in Gloucester-
shire, except that perhaps in the latter formation the oolitic grains are rather more abundant.

One of the most forcible impressions conveyed to the mind by a survey of the testacea
of this formation, when compared with that of the other members of the oolitic system, is
the great scarcity of the Cephalopoda, so few indeed are they, that the entire number procured
during the last twelve years may almost be counted. For this scarcity we think we can per-
ceive a compensation in the appearance of several genera of zoophagous gasteropods, in such
numbers as must effectually have checked any undue predominance which might have been
acquired by the phytiphagous mollusca, in the absence of the Cephalopoda. When the
Phasianellz and Naticee, which are now known to be zoophagous, are added to our species
of flesh-eating mollusca, it will at once be perceived how amply nature provided for the
maintenance of the balance of the testaceous animals during the deposition of the Great Oolite
of England. ‘The great mass of the testacea are bivalves, and in species they exceed, by

about one fourth, the united number of the Gasteropoda, Cephalopoda, and Echinodermata.
9

~

6 MOLLUSCA FROM THE GREAT OOLITE.

SUB-KINGDOM—MOLLUSCA.,

CLASS—CEPHALOPODA. Cuvier.

CrpHaLopopEs, Lamarck; Férussac.
CrpHaLopuores, De Blainville.

The remains of the Cephalopodous mollusca may generally be considered of extreme
rarity in the Great Oolite, in proportion to their abundance in the Inferior Oolite, and Lias
below, and the Kelloway rock and Oxford clay above that formation. Limited, however,
as the numbers were of the class at this particular period, the two principal orders into
which naturalists have divided the Cephalopoda, viz., the Dibranchiata and Tetrabranchiata,
were at that time fairly represented in the Nautilus, Ammonite, and Belemnite, the two
latter genera being well known as typical and characteristic of the secondary period of
geologic history.

Class.! Order. Group. Family. Genus.
Dibranchiata. Oigopside. Belemnitide. Belemnites.
Cephalopoda. (Acetabulifera, D’Orb.)
Tetrabranchiata. { Nautilide. Nautilus.
(Tentaculifera, D’Orb.) Tedanicunaeties Ammonites.

ORDER — DIBRANCHIATA. Owen.
Family—BELEMNITIDE.

Brtemnites, Bhrhart, 1727. Lam., Blainv., Voltz, D’ Orb., &e.

Navtitvs Brremnita, Gmelin.

Acamas, AcHELOIS, CaLLIRHOE, CrTOcIs, CHrysaor, Hrsouitues, Pactirss,
Poropragus, THaLtamus, De Montfort, 1808.

NovrosiIpHiTEs, GASTROSIPHITES, Duval.

BELEMNITES, PsEUDOBELUS, Blainville, 1827.

Bevemnita, Fleming, 1828.

An elongated, conical, or fusiform body, of a radiated fibrous structure (the osselet,
or guard), solid posteriorly, and more or less poimted (the rostrum); anteriorly pro-

' For a concise and interesting account of the general characters and classification of the Cephalopoda,
the reader is referred to a previous Monograph, by Mr. F. Edwards, ‘On the Eocene Mollusca,’ Part I,
Cephalopoda.

CEPHALOPODA. 7

duced, truncated and furnished with a deep conical cavity (the a/veolus), containing the
distal portion of a horny or fibro-calcareous chambered shell (the phragmacone), perforated
on the ventral part by a marginal siphuncle, and from the dorso-lateral margins of the
anterior extremity of which shell proceed two elongated, slender, testaceous processes ; the
whole body being invested with a thin, testaceous, or corneo-calcareous integument (the
capsule, or periostricum).*

On the subject of the Belemnite and allied forms, the reader is referred to the Memoir by Professor
Owen, in the ‘Phil. Trans.,’ 1844, p. 65; and the interesting papers in the same work, by G. A. Mantell,
Esq., LL.D., ‘Phil. Trans.,’ 1848, p. 171, and 1850, p. 393 ; also to the ‘ Paleontologie Francaise, Terrains
Jurassiques,’ p. 40, by M. A. D’Orbigny.

In corroboration of the interesting facts cited by Dr. Mantell, respecting the continuation of the
phragmacone of the Belemnite, we quote the following graphic statement of a writer of the last century as
bearing on the subject. ‘The remarks are contained in an account descriptive of the sinking of a well at
Montbard, in 1774.

“There were, moveover, great numbers of Belemnites, all conical, the largest being from 7 to 8 inches
long. They were pointed like an arrow at one end, and the other terminated irregularly, and was flattened,
as if they had been crushed. They were brown, both on the outside and inside, and were formed of a
material, arranged internally in transverse or radiating striz, which met at the axis of the Belemnite. This
axis was, in all, rather eccentric, and marked from one extremity to the other by a fine white line. When-
ever the Belemnite attained a certain size, the base contained a small cone, more or less long, made up of
cells, in the form of plates set one within the other (as in Nautili). The white line ended at the summit of
the cone. This small cone was invested along its whole length by a yellowish crustaceous pellicle, extremely
thin, although composed of several layers; and the body of the Belemnite (with a radiating structure),
which enclosed the whole, became thin in proportion as the diameter of the cone increased. Such,
generally, was the character of the Belemnites which were found mingled with the soil thrown out of the
shaft, and which character is common to all those of this species. In order to ascertain the position which
the Belemnites occupied in the beds, several portions were softened carefully, and it was found that they all
laid flat, and parallel with the beds. What most astonished us, and what has not hitherto been noticed, was
this, that we then perceived, that to the extremity of the base of all the Belemnites, was attached an
appendage of a yellowish colour, composed of a substance like that of the shells, and which was shaped like
the widened part of a funnel which had been flattened. Many of these were two inches long, one inch
broad at the further end, and about six lines at the point where they were attached to the Belemnite. In
examining closely this shelly or crustaceous prolongation (which was so delicate that it could scarcely be
touched without breaking), I observed that this part of the Belemnite, which has not hitherto been recog-
nised, is nothing more than the continuation of the thin shell or crust which covers the little chambered
cone, of which I have already spoken; so that it may be said, that all Belemnites which are at present to
be found in collections of Natural History are imperfect ; and that the portion we are acquainted with is
only, as it were, the case or covering of a portion of the shell which at one time enclosed the animal.”

Buffon, ‘ Epochs de la Nature,’ iii, Epoch 5, p. 143.

‘Historie des Mineraux, des argiles et de glaises,’ vi, p. 122.

The above passage is translated from the ‘Explication de la Carte Geologique de France,’ tom. 2,

p. 350.

8 MOLLUSCA FROM THE GREAT OOLITE.

Br.emnites Fustrormis, Park. Plate I, figs. 6, 8.

BELEMNITES FUSIFORMIS, Park. Org. Rem. iii, p. 127, t. 8, f. 13, 1811.
— — Miller. Geol. Trans., 2d Series, ii, p. 61, t. 8, f. 22, t. 9,
figs. 5, 7.
= — Brown. Illust. Foss. Conch., p. 41, t. 29, f. 14.
—_ — Flem. Brit. Anim., p. 240.
— Fievrrausus, D’Orb. Pal. Franc. Terr. Jur., p. 11, t. 13, figs. 14-18.
— _ Buckman. Geol. of Chelt., t. 3, f. 9.

B. Testa elongaté, gracili, anticé compressa, attenuata, posticé depressd, acutissimad
subtus longitudinaliter sulcatd, sulco posticée, anticéque non interrupto ; aperturd compressa.
(D’Orb.)

An elongated, smooth, somewhat fusiform Belemnite, somewhat compressed anteriorly
and depressed posteriorly, terminating in a rather sharp point; marked throughout the
whole length by a deep single uninterrupted furrow, slightly enlarged towards the point of
the rostrum. Alveolar cavity occupying about a fourth of the length. There is some
slight confusion respecting this species, which is undoubtedly the shell alluded to by
Parkinson in the work above cited, and described by Miller as coming from the Stonesfield
slate, near Woodstock. The specimens figured (PI. I, figs. 6—8), are from that locality. It
appears also to be identical with the B. Meuriausus, D’Orb., which is found in the Great
Oolite in the environs of Lucon (Vendée). We are further confirmed in this opinion by the
fact that Professor Buckman has identified and figured, in the work above referred to, a
Belemnite under the name of B. Flewriausus, as occurring in the Stonesfield slate of Glou-
cestershire, which is identical with our shell from the same deposit in Oxfordshire, the
latter beg the original locality from which the species was first obtained. The con-
fusion appears to have arisen from the English specimens having been confounded with the
B. hastatus, Blainville (Hiébolithes, Monifort), from the Oxford clay, at least it is so quoted
by M. D’Orbigny (‘ Pal. Franc. Terr. Jur.’ p. 121), and also by Bronn (‘ Index Palzon-
tolog.,’ p. 156), an opinion that Mr. Miller may possibly have induced, inasmuch as he also
considered De Montfort’s species to be synonymous with the B. fusiformis.

Locality. The Stonesfield slate of Stonesfield ; and Eyeford near Cheltenham.

Br.emnitses Busstnus, D’Ord. Plate I, figs. 5, 7.

BELEMNITES Bessinvus, D’Orb. Pal. Frang. Terr. Jur., p. 111, t. 13, f. 14-18.
— CANALICULATUS, Buckman. Geol. of Chelt., p. 71, t. 3, fig. 8.

B. Testa elongata, anticé compressd, postice depressd, subtus longitudinaliter sulcatd,
sulco postice interrupto, aperturd compressd. (D’Orb.)

An elongated, smooth, very slightly fusiform shell anteriorly compressed, posteriorly
depressed, marked throughout the whole length by a furrow which is wider, and slightly
divided towards the point.

CEPHALOPODA. 9

The specimen figured appears to be the same as the B. Bessinus, D’Orb., from the Inferior
Oolite of Port-en-Bessin (Calvados) ; the general proportions are similar, about eight times
as long as wide, and the division of the furrow may be faintly traced in some specimens.
It is probably identical with the shell figured by Professor Buckman (loc. cit.) as B. cana-
Licatus, Schlot., but that species is stated by M. D’Orbigny to have an equally impressed
furrow, whereas, in our specimens, it is always expanded towards the point of the rostrum.

Locality. The Stonesfield slate of Stonesfield, and Sevenhampton near Cheltenham.

ORDER—TETRABRANCHIATA. Owen.
Family—NavtTiLip&.

Nautiuus, Linneus.

Bisipu1tes, Oceanus, De Monffort.
OmpHatia, De Haan.
NavutiLites, Schlotheim.

A discoidal, convoluted, multilocular shell, compressed or ventricose, with contiguous
volutions, the last one generally concealing the others, septa transverse, concave, and some-
times sinuous, with entire margins, more or less centrally perforated in their disc.

Navtitus pispansus. Plate II, figs. 5, 5a.

NV. Testé subglobosd, late umbilicatd, anfractibus rotundatis, lateraliter subcarinatis ;
apertura dilatatd, subovali ; septis (?), siphunculo (?).

A somewhat globose and smooth shell, with rapidly increasing volutions, and a large
and rather deep umbilicus, exposing the previous volutions ; umbilicus occupying about
one third of the diameter of the shell; volutions rounded on the back, and slightly cari-
nated towards the base by the obliquely flattened form of the outer margin of the
umbilicus. Aperture expanded, arched, semi-ovate, wider than high.

Septa and Siphuncle not visible in the specimen described.

Diameter of the aperture : : 63inches
Height of the : ; ; 33 Cs,
Volutions increase in size (increasing about 2 in the

volution), from . : : 24 to 63 in.
Height of re-entering volution lobe 3

This species is closely related to JV. excavatus, oad ‘Min. Con’ tab. 529, f. 1, from the
Inferior Oolite of Dorsetshire ; but it is readily distinguished from it by the more oval form
of the aperture ; the width of the umbilical opening, in proportion to the diameter, is also

10 MOLLUSCA FROM THE GREAT OOLITE.

different, being in JV. dispansus about one third, and in JV. eacavatus about the half of
the diameter of the shell ; the form also of the umbilical cavity varies im the two species ; in
NV. excavatus, the sides of the cavity are regularly conical, as shown in Mr. Sowerby’s figure,
above quoted, and in the ‘ Pal. Fran. Terrains Jurassiques,’ t. 30 ; in V. dispansus the outer
margin of the umbilicus is obliquely flattened, or subconical, the inner side being
rather steep.

A single specimen only has been found of this species in the shelly beds of the Great
Oolite near Minchinhampton.

Navtitus Baseri. Plate I, figs. 1, la.

N. Testé discoided, compressa, levigatd, subumbilicatd ; anfractibus angulatis, com-
pressis ; apertura compressa subquadrata ; septis vie sinuosis ; siphunculo (?)

A compressed, smooth shell, or only slightly marked by the lines of growth, with
angular embracing volutions, leaving but a faint trace of an umbilical cavity; aperture
somewhat quadrilateral, narrowed above, and wider than it is long ; the septa are slightly
sinuous, curving towards the umbilicus and outer margin.

This species is allied to JV. truncatus, Sow., from the Lias, but is distinguished by the
form of the mouth, and character of the septa.

Locality. Great Oolite near Minchinhampton.

We have much pleasure in dedicating this species to our friend, James Baber, Esq., of
Knightsbridge, whose interesting collection of fossil remains is always liberally opened to
public view.

Navtitus susrruncatus. Plate I, figs. 2, 2a.

NV. Testa discoided, inflata, levigatd, sulcatd, subimperforatd ; anfractibus rotundatis
(jun.), subangulatis (adulta) ; apertura depressd, subquadratda ; septis (?), siphunculo (?).

A smooth, or slightly furrowed, and somewhat inflated shell, with rounded and
embracing volutions in the young state, which become truncate, or subquadrate, in the adult,
and having a very shallow, or slightly impressed, umbilicus. Aperture about. twice as
wide as it is high, flattened above, and somewhat compressed laterally.

This shell has the general form of the JV. datidorsatus, D’Orb. ‘Terr. Jur.’ t. 24, but the
broad umbilicus and more quadrate form of the young shell in that species readily
distinguish them. This species belongs to the section of imperforate Nautili, of which
LV. truncatus, Sow., NV. clausus, D’Orb., are examples ; a group, the species of which were
not apparently very numerous during the Jurassic period.

Locality. Great Oolite near Minchinhampton.

a

CEPHALOPODA. 1]

ORDER—TETRABRANCHIATA.
Family—AMMONITIDS&.

Ammonites, Brugiere. 1789.

OPHIOPOMORPHITES, Plott.

PLANORBITES, ORBULITES, GLOBITES, PLANULITES, Lam.
AMALTHEUS, PLANULITES, De Montfort.

PuLanitTEs, GLopites, De Haan.

NavtiLus, Akgonauta, Reinecke.

AMMONITA, ORBULITA (pars.), Fleming.

A more or less discoidal, multilocular shell, with contiguous volutions; volutions
generally visible, septa transverse, with sinuated edges, perforated by a single tube, situated
close to the outer margin.

AMMONITES SvUB-conTRacTUS. Plate II, figs. 1, la, jun., figs. 2, 2a.

A. Testé discoided, subglobosd, costaté, umbilicatd, anfractibus involutis, rotundatis
compressis, lateribus 16—18 costatis, costis obtusis bi-trifurcatis, in dorsum continuis ;
apertura semiellipticad subcontracta ; umbilico magno, excavato, subconica.

A sub-globose, deeply umbilicated, and costated shell, with sixteen to eighteen obtuse
ridges (tubercles?) surrounding the margin of the umbilical cavity, from each of which
three or four smaller costa pass over the somewhat depressed and rounded back.
Aperture, semi-elliptical.

Proportion of umbilicus to diameter, rather more than one-half. Diameter, 5 inches.
Thickness, 3 inches. Height of aperture, 14 inches, twice as wide as it is high.

The specimen from which our figure is taken has been much worn by clearing it
from the original matrix, but a careful examination discloses the prominent marginal costz,
as well as the smaller ones which arise from them and pass over the back.

In the umbilicus, the marginal coste are well exhibited, which in the young state were
more compressed, and continued on the inner side of the cavity.

This species is distinguished from the Ammon. coronatus, Brug., by its more globose
form, less conical umbilicus, and the more arched and less expanded aperture. It is closely
allied to Am. contractus, Sow., and in a young state might be mistaken for that species ;
but the ribs are larger and not so numerous or elevated ; the less embracing volutions, and
the more contracted form of the aperture in the adult shell, are also characters by which it
may be distinguished.

Unfortunately the determination of the species, and their varieties of the Ammonites in
the Great Oolite of Minchinhampton, is rendered extremely difficult, in consequence of the
great rarity of specimens, and their state of preservation, rarely allowing the least trace of
the sinuated edges of the septa to be observed.

12 MOLLUSCA FROM THE GREAT OOLITE.

AmMonitEs ARBusTIcERUS, D’Ord. Plate I, figs. 4, 4a.

AMMONITES ARBUSTIGERUS, D’Orb, 1848. Pal. Frang., Terr. Jur., p. 414, t. 143.
_— _ D’Orb. 1850. Prod. Paléont., p. 296.

A. Testé compressa, anfractibus rotundatis, latis, lateribus convexis transversim 22
costatis ; costis obtusis bi-trifurcatis vel intermediis, dorso sub-convexo ; apertura oblonga,
compressa.

A discoidal, costated shell, with somewhat convex and gradually increasing volutions ;
umbilicus large: the principal cost are obtusely rounded, and about twenty-two in number,
bifurcating as they pass over the back, having occasionally an intermediate rib; back
convex ; aperture oblong. |

Locality. In the Great Oolite of Minchinhampton, and described by M. D’Orbigny
as occurring both in the Great and Inferior Oolite of Normandy.

Ammonites MACROcEPHALUS, Schloth., var. Plate II, figs. 3, 3a.

AMMONITES MACROCEPHALUS, Schloth. 1813. Min. Tasch. vii, p. 70.
— — Schloth. 1820. Petref., p. 70, No. 16.
a _ Zieten. 1850. Pet. Wurtemberg, t. 5, f. 1, 4.
_ — D Orbigny. 1848. Pal. Frang. Terr. Jur., p. 430, t. 151.
~ _— D Orbigny. 1850. Prod. Paléont., p. 127.

A, Testdé discoided, sub-globosd, anfractibus involutis, rotundatis, costatis: costis
20—30 obtusis, medio laterum bifurcatis ; aperturd semi-ellipticd ; umbilico subcontracto.

An inflated, or somewhat globose shell, with rather depressed volutions, and a narrow
and deep umbilicus, from the margin of which arise about twenty to thirty obtuse ribs,
which bifurcate in passing over the back. Back convex; aperture semi-elliptical.

We have ventured to assign our specimens to the Ammonites macrocephalus of
Schlotheim, although their imperfect state of preservation renders this identification
somewhat doubtful. The specimens of this species hitherto obtained by us from the
Oolite, are always in the state of casts, and very much eroded, so that the principal ribs
which surround the umbilical cavity, are nearly obliterated, as shown in the figure,
tab. 2, fig. 3.

Locality. Great Oolite near Minchinhampton.

AmMONITES GRaciLis, Buckman. Plate I, figs. 3, 3a.
AMMONITES GRACILIS, Buckman. 1845. Geol. of Chelt., p. 104, t. 3, fig. 6.

A. Testa discoided, compressa, anfractibus ovatis lateribus sub-complanatis, transversim
30—40 costatis ; costis bi-trifurcatis vel intermediis, in dorsum continuis, apertura ovata,
sub-sagittata.

A discoidal, compressed, ribbed Ammonite, with six to eight oval, slowly increasing

CEPHALOPODA. 13

volutions, the last formed partly concealing the previous ones, with about thirty to forty
rounded or obtuse and nearly straight ribs on the inner margin, which generally become
bi- or trifurcate about the middle of the volution, and some pass over the back, giving it
a costated appearance; the ribs, however, are not aways confluent, an intermediate one
frequently arising about the middle of the volution; from the manner in which each
volution is enveloped, the previous ones only exhibit the simple cost, as seen in the
specimen figured at Tab. I, fig. 3. The aperture is semi-ovate and compressed. The
sinuosities of the septa are not to be traced with any degree of accuracy, but they appear
generally to resemble those indicated by D’Orbigny. ‘ Terr. Jurass.,’ t. 148. (dm. Bakerie.)

Differing as our figure’ does from that given by Prof. Buckman in the ‘ Geology of
Cheltenham,’ we have no doubt of the identity of the specimens, having been enabled,
through the kindness of that gentleman, to compare the original form. ll the
specimens we have examined of this species are more or less compressed, and this cause
may have partly influenced the peculiar saggitate form of the aperture in the individual
shell selected by Prof. Buckman for illustration.

The costze which ornament this shell in the young state, and for a considerable period
of its growth, become partially obsolete in a more advanced stage. Perfect specimens of
this shell, showing the fact, are excessively rare, but we have collected large fragments of
this species on Sevenhampton common, in which the character is clearly exhibited.

Locality. The specimen figured is in the colleetion of James Baber, Esq. F.G.S., and
was obtained from the Stonesfield slate of Stonesfield. It also occurs in the same
formation at Sevenhampton common.

Ammonttes WatrrnovsEl. Plate I, figs. 4, 4a.

Ammonitss piscus, D’Orb. Terr. Jurass., p. 394, t. 131.
— — DOrb. Prod. Paléont., p. 296. 1850.

A. Testé compressa, sub-carinatd, anfractibus compressis, latis, externé angulatis ;
levigatis ; dorso acuto ; umbilico angustato ; apertura sagittata.

A compressed, discoidal shell, formed of very compressed and nearly embracing
volutions ; the inner half of the shell flattened and smooth; the outer, with obtuse, rather
distant and flexuous costae, terminating near the margin ; keel acute; mouth sagittate.

This specimen, from the Great Oolite of Minchinhampton, agrees in all the characters
with the Am. discus, figured and described by M. D’Orbigny, ‘Terr. Jurass.,’ pl. 131, and

1 Unfortunately the specimen figured illustrates only the young state or inner volutions of this species,
not having received at that time the finer specimens belonging to Professor Buckman, and from which the
following description was drawn up: “4. gracilis. Keel crenated ; volutions six or seven, half concealed ;
ribs straight, passing over the back, and thus making the crenations of the keel; sometimes two or three
ribs are confluent towards the front; diameter about 9 inches; thickness 1} inches; aperture sagittate.”’
(Geol. of Chelt., p. 104.)

3

14 MOLLUSCA FROM THE GREAT OOLITE.

which is cited by that author as occurring both in the Great and Inferior Oolite of
Normandy. We also possess the same species from the Inferior Oolite of Bridport and
Gloucestershire. It differs, however, essentially from the original specimen of Am. discus,
Sow., described in the ‘ Min. Conch.,’ tab. 12, which has a more regular, sagittate aperture,
and does not possess the central flattened space, so characteristic of our species.

Locality. Great Oolite of Minchinhampton, Zycett. In the same formation at
Ranville (Calvados), Niort (Deux Sévres), Mansigny (Vendée), D’ Orbigny. In the Inferior
Oolite at Bridport, and near Stroud; Eterville and Moutiers (Calvados).

We have much pleasure in assigning to this species the name of G. R. Waterhouse,
Esq., whose arrangement and careful study of the Cephalopoda, contained in the National
Collection, have materially assisted this branch of Paleontology.

CLASS-—-GASTEROPODA. Cuvier.

ORDER— PrososrancuiaTa. M. Edwards.

CrENOBRANCHIATA, Schwezgger.

Family—StROMBIDS.

Prerocrera, Lamarck, 1801.

Shell turrited, ventricose, spire usually short, aperture oval, having a lengthened canal at
both extremities, outer lip expanded into hollow thickened spies, with an anterior sinus
separate from the caudal canal.

Prerocera iGNopinis. Plate II, fig. 14.

P. Testa parva turbinata; spird breviusculé; anfractibus levigatis, planatis (3—4) ultimo
obsolete transversim bicarinato; carind superiori obsolete nodosa; cauda brevi.

Shell small, turbinated, spire short, whorls smooth, flattened (83—4), the last whorl twice
carinated, the upper carina obscurely nodulous, canal short.

The great breadth of the whorls, and the obscurely bicarinated last whorl, are the leading
features. This shell approaches A/aria levigata; but in that species the spire is much more
lengthened, and the volutions do not become angular, until at least five have been com-
pleted, it then produces small processes, which are deciduous, and the last whorl does not
attain any undue magnitude ; but, in the species before us, the fourth volution is large, has
considerable squareness, but with scarcely any distinct carina.

Locality. Rare in the planking of Minchinhampton Common.

GASTEROPODA. 15

Prerocera Bentizys. Plate III, figs. 15, 15a, var. fig. 16.

P. Testé turritd, anfractibus convexis, costis transversalibus (4); anfractu ultimo per-
magno, et costato; labio eaterno palmato digitis quinque divaricatis ; canali obliquo elongato.

Shell turrited, turbinated, whorls convex, costated, costee (4) transverse, last whorl very
large and costated, the costee terminate in an expanded palmated wing, digitations five in
number, beneath which are numerous diverging lines which connect the wing with the
caudal extremity.

The whorls are oblique in their upper and cylindrical in their lower portions; their
encircling ribs are unequal and irregular; no other markings are preserved ; but the con-
dition of the specimens is scarcely so good as could be wished. The wing is enormously
expanded ; the spines extend a little beyond the connecting portions of the wing.

Locality. The Stonesfield slate at Collyweston has furnished the present specimens.
The specific name in compliment to John F. Bentley, Esq., of Stamford, who has enriched
our knowledge of the fossils of that locality.

Auarta. Vov. Gen.

A. Testé turrité, alaté et caudaté, ald integra vel digitata, interdum varicem formant;
canali posteriort nullo, labro sinistro tenut, nunguam calloso nec anfractum ultimum obti-
genti, labro dextro interdum ultra anfractum ultimum extenso, canali anteriort producto aut
breviusculo.

Shell turrited, winged, and with a caudal extremity, wing entire or digitated, sometimes
produced into a thickening or varix, no posterior canal, left lip thin, never thickened, nor
extended upon the penultimate whorl, right lip sometimes extended slightly upon the
penultimate volution, anterior canal either produced and lengthened or short.

This genus is constituted to receive a numerous group of winged shells, which are
separated from the true Strombide, Rostellariz, and Pterocerae by a simple but important
distinctive character, viz. the absence of a posterior channel upon the spire. ‘The greater
number of our Great Oolite species of Strombidz will be found to range themselves
under this division of the family; the character of the wing is various, consisting either of
a simple, undivided, and thickened process, or divided into two or more digitations ; the
channel, likewise, may be either short and straight, or lengthened and curved ; the inner
lip is always thin—usually effuse and scarcely visible, but never produced into a thickened
posterior ridge, as in the true Rostellariz ; the wing, in some instances, is extended slightly
upon the penultimate volution, which is its utmost limit.

Another character of some importance, first noticed by Mons. Deslongchamps, and
which appears to characterise this group of shells, is this: the animal, after having
developed the right margin of the shell, continued to increase in growth, and (like the
species of Mwrex and Ranella) reproduced a second dilated and digitated margin, similar

16 MOLLUSCA FROM THE GREAT OOLITE.

to the first, and generally opposite to it, a character rarely if ever found in the recent
Pterocere or Rostellarize.'

Auarra armata. Plate III, fig. 1, la.

A. Testé turritd, anfractibus carinatis, et angulato-nodosis, nodis prominentibus 6 in ambitu.
Anfractu ultimo gibbo, bicarinato; carindé superiort prominentiort spinis acutis; in @tate
juniori digitis tribus parvis; in etate adultd digitis superioribus duobus longissimus. Cauda
longa curvatd. Striis tenuissimis confertis transversis, plerumque obsoletis.

Shell turrited, whorls carmated, angulated and carinated im their middle portion;
nodules 6 in a volution. The last whorl has three carine, the last of which is nearly
obsolete. In the young state it has three small digitations; when adult, the two superior
carine are extended into very long digitations; the first carina having two angular pro-
minences or spines. The entire surface of the shell has numerous fine encircling striz,
which for the most part are indistinct.

The acute spine, number of whorls, their prominently angular figure, together with the
spine upon the middle of the superior carina of the last whorl, are characteristic features ;
from 4. hamus and A. Phillipsii the character of the wing is sufficient to distinguish it.

Locality. The planking beds of Minchinhampton Common have furnished all our
specimens ; the coarse character of the deposit rarely allows the display oh the fine striz,
or other features of much delicacy. It is moderately rare.

Auaria HaMuS, Desi. sp. Plate III, figs. 2, 2a, 24.

RosTELLARIA HAaMUS, Deslongchamps. 1842. Mem. Soc. Linn. Normandie, vol. vii,
p- 173, pl. 9, figs. 32, 33, 34, 35, 36.
—_— — Desh. lam. An. sans Vert., 2d Edit., 1843, tom. 9, p. 666.
Prerocera HAMUS, D’Orb. 1850. Prod. Paléont, p. 270.

A. Testa turritd, anfractibus transversé striatis, medio angulato-nodulosis, nodulis plus
minusve crebris, ultimo anfractu gibbo, bicarinato, carind superiort majori ; apertura
trigond. Carind majore ultimo anfractu nodulosa, nodulis parvis, subobsoletis. (Des-
longchamps.)

Shell turrited, whorls transversely striated, having a circle of nodules somewhat angu-
lated in their middle part, the nodules being more or less closely arranged. The last whor!
is large; it has two carine, the first of which is much the larger, and is indented or formed
into closely arranged nodules, which are sometimes nearly obsolete.

In some specimens, the larger carina is quite smooth, in others the indentations are
oblique; the canal is short and straight.

1 Mém. Soc. Linn. de Normandie, vii, p. 171, 176. Lam. Anim. sans Vert, 2d Edit., p, 671.

GASTEROPODA. Ei

Locality. The planking of Minchinhampton Common and white stone of Bussage
contain it; but at the latter place the more delicate features are usually best preserved. It
is rather rare. Inf. Oolite, Bayeux; Great Oolite, Ranville, Normandy. (Des/.)

Auaria Lavieata. Plate III, fig. 3, 3a.

A. Testé fusiformi, anfractibus convexis, levigatis, ultimo bicarinato, carind superiori
spinigera ; spino oblongo ort opposito; ald brevissimad in etate juniort monodactylda, dein
(atate adulta) magna didactyld, digitis longis divaricatis, tenuibus, trigonis; caudd longa,
recta, apice sub-incurvo; apertura oblonga, labro sinistro subcalloso.

Shell fusiform, whorls convex, smooth, the last whorl with two carinz, the upper carina
spined ; the spme oblong, and placed opposite to the aperture; the wing very small when
young, at first it has but one digitation, with advance of growth it acquires two large digi-
tations, which diverge in opposite directions, they are smooth and three-sided ; the caudal
extremity is long and curved towards the apex; the aperture is oblong, the left lip bemg
slightly thickened.

In everything, excepting its smooth surface, this shell agrees with the Rostellaria
myurus of Deslongchamps; but as we have seen about twelve specimens, which were well
preserved, it is impossible that they ever could have had the strize which distinguish the
shell from Normandy.

Locality. It is rare, and has been found only in the planking of Minchinhampton
Common and contemporaneous beds of white stone north of the Vale of Brimscombe.

ALARIA HAMULUS, Desi. sp. Plate III, figs. 4, 4a, 40.

ROSTELLARIA HAMULUS, Deslongchamps. Mem. Soc. Linn. Normandie, vol. vii, p. 175,
pl. 9, figs. 37—40.
— _ Desh. Lam. An. sans Vert., 1843, tom. 9, p. 666.
PreRocERA HAMULUS, D’Orb. Prod. Paléont., p. 302.

A, Testé parva turritd, apice obtuso, anfractibus (5—6) carinatis nodulosis; ultimo anfractu
subgibbo, transverse striato ; strus inequalibus, majoribus alternatim minoribusque ; carind
nodulosd seu plicaté; labro externo incrassato variculam simulante; ald parva unidigitato,
apice acuto trigono, subtus canaliculato; caudd brevissimd, apertura subellipticd.

Shell small, turrited, clavate, apex obtuse, whorls (5—6) convex, nodulated, nodules
six in a volution. The last whorl has a single nodulated carina terminating anteriorly in a
slight digitation. In the immature state the digitation is produced into a hook-shaped
process. The surface has numerous encircling striz, somewhat irregular, but which are
alternately large and small. The upper margin of each whorl has a prominent line closely
tuberculated; the aperture is narrow, bemg contracted on the right side by a thickened

18 MOLLUSCA FROM THE GREAT OOLITE.

fold or varix, of which there are two upon the last volution. The inner lip is broad and
distinct, the chafinel is short and straight. A small canal passes from the aperture to the
apex of the rudimentary digitation.

M. Deslongchamps has described this species from three small specimens, which are
very imperfect, having only the last volution. The name is scarcely appropriate to full-
grown individuals which nearly lose the hook-like digitation: in one instance only have
we noticed the Aamulus of the dimensions figured by M. Deslongchamps, and this occurred
in the smallest of our specimens, which was but little larger than the Norman one. It
would, therefore, seem that this feature was of an uncertain character, and disappeared at a
later period of growth.

Locality. The beds of planking at Minchinhampton Common, and their equivalents,
the white stone of Bussage and Eastcombs, have supplied all the specimens which have
come to our knowledge. It is not very rare. In the Great Oolite (pierre blanche),
Langrune, Normandy. (Des/.)

Avaria Puiiuirsi, D’Ord. sp. Plate III, figs. 5, 5a.

Prerocera Puitiresi, D’Orb. 1850. Prod. Paléont, p. 270.
RosTELLARIA composiTa, Phil. 1835. Geol. Yorksh., i, t. 9, fig 28, (not Sow.)

A. Testa turritd ; spird elongaté; anfractibus numerosis, convewis, vel subangulatis,
transverse striatis, et costis obliquis numerosis approximatis ; anfractu ultimo bicarinato ;
alé unidigito, caudda recta, breviusculd.

Shell turrited; spire elongated; whorls numerous, convex, or subangulated, trans-
versely striated, and ornamented with numerous closely-arranged oblique ribs upon the
lower half of each whorl ; the last whorl is striated and bicarinated, terminating in a simple
or undivided wing; the caudal extremity is straight, smooth, and of moderate length.
A. hamus is the species which approximates most nearly to it; but in that shell the
longitudinal cost are less numerous, not oblique, and are visible throughout the length of
the whorl; whereas in the 4. Phillipsit they occupy the lower half only, and form an angle
at their upper termination. The upper and larger carina upon the last whorl is more
smooth and less prominent than in the 4. Aamus, and the entire form of the shell more
lengthened or slender.

Locality. Scarborough, in dark chocolate-coloured argillaceous shale. Great Oolite,
(Phillips.)

Auaria pacopa. Plate ITI, fig. 6.

Testé turrité ; anfractibus numerosis, in medio carinato-crenatis, ultimo bicarinato ;
carinis tuberculatis ; anfractibus transverse striatis; striis duabus prominentibus suturam

GASTEROPODA. 19

approximantibus. Ald magnd, expansd, in digitos duobus productd, digitis parvis, caudd
brevissima.

Shell turrited ; whorls numerous, each with an acute mesial carina, the last whorl with
two carinez ; the edges of the carina undulate and are nodulated ; the whorls are trans-
versely striated above the carina; beneath are two prominent striz, bordermg the suture ;
wing large and expanded, extended into digitations ; the digitations are small, the caudal
termination very short.

This elegant shell possesses a certain family resemblance, which places it near to several
of our Great Oolite examples of the genus. The acute carina reminds us of 4. ¢rifida, the
nodules of 4. Aamus, and the general figure of the wing and caudal extremity of 4.
paradoxa ; the whorls are comparatively numerous and narrow, the mesial carma very
prominent, and the junctions of the whorls strongly defined.

Locality. The white stone of Eastcombs has furnished our only example.

ALARIA ATRACTOIDES, Des/. sp. Plate III, figs. 7, 7a.

PreROCERA ATRACTOIDES, Deslongchamps. Meém. Soc. Linn. de Normandie, vol. vii,
p- 166, pl. 9, figs. 7, 8, 9.
— — Desh. lam. An. sans Vert., 2d Edit., 1843, tom. 9, p. 681.
_ — D’ Orb. Prod. Paléont., p. 302.

A.“ Testa fusiform, transversim striata ; strivs alternis altioribus ; anfractibus bicarinatis
(carina superiore majore) longitudinaliter plicato-nodosis, plicis remotiusculis, nodis quadratis,
acutis, ultimo anfractu subgibbo ; caudé longa, incurvd.” (Deslongchamps.) Ald expansd
in digitis trigonis quatervis vel quinque (digito superiort majort).

Shell fusiform, transversely striated ; strize alternately elevated ; whorls twice carinated
(the upper carma being the largest), longitudinally nodulated and plicated ; the plications
remote, the nodules square and acute. The last whorl is large, the canal long and curved,
the wing expanded, having four and perhaps five triangular digitations, of which the
upper one is the largest.

We have three specimens of this rare shell, in one of which the wing is well developed,
with the exception of the extremity of the lower digitation, which may be imperfect.

Locality, The planking beds of Minchinhampton Common. Great Oolite (cazdlasse),
Ranville, Normandy. (Desi.)

ALARIA HEXAGONA. Plate III, fig. 8.

A. Testa turrité ; anfractibus paucis (4), angulatis et nodulosis ; nodulis 6 hewagonis ;
ultimo anfractu unicarinato, nodulosa, varicem ort oppositum gerente. Ald parvd, caudd
sublonga ; apertura contractd, ovatd ; labro sinistro tenut.

Shell turrited ; apex obtuse; whorls few (4), prominently angulated and nodulated ;

20 MOLLUSCA FROM THE GREAT OOLITE.

nodules 6 in a volution, giving it a six-sided aspect, The last whorl has a single nodulated
carina, which has a.prominence placed opposite to the aperture. The wing seems to be
but little produced, and is not divided into digitations. The canal is rather long and
straight ; the aperture ovate and contracted ; the left lip thin.
This is a rare species, of which we have only seen about six specimens: all of these
have been more or less imperfect, the wing being badly preserved, or wanting altogether.
Locality. The planking beds of Minchinhampton Common.

Auaria PARADOXA, Des/. sp. Plate III, figs. 9, 10.

PTEROCERA PARADOXA, Deslongchamps. 1842. Mém. Soc. Linn. Normandie, vol. vii,
p- 170, pl. 9, figs. 16—18, 20—22.
~ — Desh. Lam. An. sans Vert., 2d Edit., 1843, tom. 9, p. 682.
— — D'Orb. 1850. Prod. Paléont., p. 302.

A. Testé parva ovaté ; spird breviusculd obtusd ; anfractibus 7 angulato-nodosis, nodis
remotiusculis ; ultimo anfractu pluricostato, costis transversis subequidistantibus, et inequa-
hbus ; caudé brevi, recté; ald angustd, varicem simulante, pluri-dentatd, dentibus inequa-
hbus subtis canaliculatis, aperturé angustatd, varicem formante.

Shell small, ovate ; spire moderately elevated, obtuse ; whorls angulated and nodulated,
the nodules being distant, or about 7 im a volution. The last whorl has plain transverse
ribs, nearly equidistant, and slightly unequal in size. The canal is short and straight ;
the wing is thickened into a kind of varix at the aperture, which is contracted.

The spire bears a larger proportion to the last whorl than appears in M. Deslongchamps’
figures, which may be accounted for by his having restored the former portion from another
specimen ; exactness in such a case is not to be expected.

This species is comparatively rare. We have scarcely seen one which is perfect.

Locality. Great Oolite of Minchinhampton. Bath Oolite (pierre blanche), Langrune,
Colleville, Normandy. (Deslongchamps.)

Avarta Parapoxa, var. Plate III, fig. 9a.

Shell ovate ; spire moderately elevated; whorls (6) convex, rendered angular by pro-
minent tubercles, of which there are seven or eight in a volution; the last whorl is large,
has numerous transverse ribs, of which two are more prominent; the ribs terminate in
smal] digitations ; there is also a large bifid spine placed opposite to the wing.

As compared with 4. paradoxa, the spire is more elevated, and bears a larger pro-
portion to the body whorl; the encircling ribs upon the last whorl are much more elevated
and unequal, the two larger ones giving a kind of bicarinated aspect to it, and terminating
in digitations, which are much larger than in the former shell. The large bifid spine upon

GASTEROPODA. 21

the opposite side of the whorl is another distinctive character. The caudal extremity is
short and straight. Length, 10 lmes; breadth, including digitations, 9 lines. ,
Locality. This species is found in all the shelly beds, but is far from common.

Auaria TRriFIDA, Phil. sp. Plate III, figs. 11, lla, 114, 1le.

ROSTELLARIA TRIFIDA, Phillips. 1835. Geol. of Yorksh., i, t. 5, fig. 4.
— BISPINOSA, Phillips. Geol. of Yorksh., i, t. 4, fig. 32.
— BICARINATA, Goldfuss. Petref, t. 170, fig. 1.
— TRIFIDA, Deslongchamps. Mém. Soc. Linn. Normandie, vol. vii, pl. 9,
figs. 28, 29, 30, 31.
—_ — Desh. lam. An. sans Vert., 2d Edit., t. 9, p- 665.

A. “ Testi fusiform, turrita, transverse striata, anfractibus medio carinato-acutis ; ultimo
bicarinato, gibbo ; ald didactyld, digitis in etate adultd longissimis, recurvatis ; in juniore
modo unico, modo duobus inequalibus digitis, seu inferiore, seu superiore longiore ; caudd
longissimd, recurvatd ; apertura angustata.”’ (Deslongchamps.)

Shell fusiform turreted, transversely striated ; whorls acutely carinated about the middle
part ; the last whorl has two carine, the upper of which is most prominent, and has a
prominence or spine opposite to the aperture. ‘The wing is digitated; when full grown
the digitations are very long and recurved, the larger bemg sometimes the upper, and at
other times the lower digitation. In the young state it has only one carina and digitation.
The canal is very long and recurved, the aperture small.

Having had the advantage of examining a large number of specimens, comprising every
variety both in form and stage of growth, we feel no hesitation in uniting the two species
here indicated. The whorls have every degree of angularity, specimens of A. dispinosa
having the lower half of each volution simply cylindrical, the carina not projecting beyond
it, and the first three or four whorls are smooth and simply convex, scarcely showing any
trace of angularity. ‘The extreme of the other variety has the carina not only angulated
acutely, but spread out horizontally into a prominent tabular border.

The encircling strize are equally variable. In some instances the striz are regular and
equal, but more frequently they are alternately large and small; at other times, however,
they are altogether irregular and unequal.

Locality. This species occurs throughout the whole of the Great Oolite near Minchin-
hampton ; even the upper beds, when shelly, not unfrequently contain it. Undoubtedly it
is the most common example of the genus. In the Calcareous grit; Oxford Clay; Kelloway
Rock, near Scarborough, Yorkshire (PAzdips).

M. E. Deslongchamps describes this species as occurring throughout the jurassic series
of Normandy, viz. the Zzas, Fontaine-Etoupefour ; Inferior Oolite, Bayeux ; Great Oolite,
Ranville; Oxford Clay, Vaches-Noires ; Kimmeridge Clay, Villerville.

4

22 MOLLUSCA FROM THE GREAT OOLITE.

ALARIA PARVULA. Plate II], fig. 12¢, 126.

A. Testé parva, turritd ; anfractibus quinque convexis, angustatis, levibus, ultimo planato,
striato; striis transversis, crebris, acutis, subcrenulatis ; caudd brevissimd ; ald—?

Shell small, turreted, volutions (5) convex, narrow, smooth, the last volution flattened,
striated, strize transverse, closely arranged, acute, and slightly crenulated ; the canal nearly
obsolete ; wing unknown.

Locality. The planking of Minchinhampton Common has furnished only one well-
preserved specimen with which we are acquainted,—it does not exceed 6 lines in length;
the whorls are very narrow and convex, the striz being visible only upon the body whorl.

AvartA? cirrus, Desi. sp. Plate III, figs. 13, 13a.

RosTELLARIA CIRRUS, Deslongchamps. 1842. Mém. Soc. Linn. Normandie, vol. vii,
p. 178, pl. 9, f. 26.
—_ — Desh. Lam. An. sans Vert., 2d Edit., tom. 9, p. 668.
PreRocera cirRUS, D’Oré. 1850. Prod. Paléont., p. 302.

A. Testa turritd, transversim striata, apice acuminato; anfractibus medio carinatis, ultimo
inflato, bicarinato ; carind superiori eminentiori, gibbum transverse oblongum ori oppositum
gerenti: ald brevissima, in etate juniori monodactyld, deinde (etate progredienti) didactyld,
digitis longis, divaricatis, tenuibus, trigonis. Cauda longissimd, rectd, apice incurvo.
(Deslongchamps.)

Shell turreted, apex pointed, transversely striated, whorls carimated in the middle, the
last whorl inflated, having two carine; the first carma being the most prominent. A
transverse prominence is placed opposite to the aperture; the canal is long and straight,
except the extremity, which is curved.

A single specimen, in which the last whorl is imperfect, is all we have to refer to; the
form, however, is unequivocal; the spire is unusually short and ventricose, as compared
with other examples of the genus, and in the stage of growth which our specimen exhibits,
had not acquired the large digitations and caudal extremity proper to a later period.

Locality. Minchinhampton Common ; it must be referred to some of the shelly beds
beneath the planking; rare. Great Oolite, Ranville, Normandy. (Des/.)

Family—MovRicip&.
Fusus, Zam. 1801.

Shell fusiform or subfusiform, ventricose in the middle, with an elevated spire, volutions
convex, generally costated or striated ; aperture ovate, terminating anteriorly in a more or
less elongated canal, outer lip entire, sharp; columella smooth.

GASTEROPODA. 23

Fusus muuticostatus. Plate V, fig. 6, 6a.

F. Testa parvd, turritd, turbinatd, anfractibus convexis (5—6), suturis profunde separatis ;
costis longitudinalibus numerosis, obliquis, striis transversis, crebris; aperturd parvd, cauda
breviusculd.

Shell small, turreted, turbinated ; whorls very convex, 5—6 in number; the sutures
being deeply impressed, the cost are longitudinal, rounded, and directed obliquely from
left to right; there are also numerous closely-arranged transverse strie ; the aperture is
small, the canal short.

Locality. The planking bed of Minchinhampton Common has afforded this pretty
little species : it is moderately rare.

Fusus coronatus. Plate V, fig. 5.

F. Testé parva, turritd, anfractibus convexis, angustatis et nodulosis (nodulis 9), parte
superiort transverse trilineatis; anfractu ultimo ventricoso ; basi levi, caudd subrectd.

Shell small, turreted, whorls convex, narrow, and nodulated; nodules about 9 in a
volution, with three encircling lines beneath the middle of each volution ; the last whorl is
ventricose, the caudal extremity nearly straight.

The general aspect of this little species has some resemblance to a Rostel/aria; there
does not appear, however, to be any expanded wing or other characteristic features of that
genus. |

Locality. It is very. rare. We have obtained only three specimens, which occurred in
the planking of Minchinhampton Common.

Fusus? sus noputosus, D’Ord. Plate V, fig. 9, 9a.

Fusus susnoputosus, D’Orb. 1850. Prod. Paléont., p. 303.
— NopuLosus, Deslongchamps. Mém. Soc. Linn. Normandie, vol. vii, pl. 10,
figs. 36, 37, (Not Sow., 1837.) (Not Lamarck.)

F. Testé minutd, ovato-turritd, acuta ; anfractibus rotundato-inflatis, transverse striatis,
nodulis (6) subobliquis, longitudinalibus ; columella marginatd, aperturd ovata, caudd
breviusculd.

Shell minute, ovately turreted, acute; whorls rounded, tumid, transversely striated;
nodules 6 in a volution, longitudinal, and rather oblique ; columella marginated, aperture
ovate, caudal extremity short; length, 3 lines.

The transverse striz are not mentioned by M. Deslongchamps; but in the specimen
which we have figured they are very distinct.

24. MOLLUSCA FROM THE GREAT OOLITE.

Locality. t would appear to be very rare, and has been found only in the planking of
Minchinhampton Common ; but with this and other minute shells it is not easy to form an
accurate notion of their actual numbers. In the Bath Oolite of Langrune, Normandy.

(Desi.)

Bracuytrema. JVov. Gen.

Fusus. Species in part. Auet.

The Great Oolite shells, which we have placed under this generic designation, present
characters so much at variance with the received ideas of Fusus, that we have been induced
to erect them into a new genus, under the name Brachytrema ; the definition of this form,
whether it be regarded as subdivision of Fwsus, or as a distinct genus, is as follows :—

B. Testé turrité, turbinaté ; anfractibus convexis et costatis, nodulosis, aut cancellatis ;
labro dextro tenui ; columella rotundatd, levi, ad basin contortd; canali brevi, obliquo.

Shell small, turreted, turbinated; whorls either costated, nodulated, or cancellated ;
the last whorl large and ventricose; right lip thin and smooth; columella smooth, rounded,
twisted near to the base, and reflecting outwards, forming a short oblique canal; aperture
moderately large, subovate, its length being usually less than that of the spire.

The general figure of this genus is turbinated, and nearer to Buccimum than Fusus ; it
has, however, the base and channel of Cerithiwm; the short oblique canal and twisted
columella separate it from Fusus, the genus to which the known species have most
frequently been referred. The following forms may possibly be assigned to this genus :—
Murex haccanensis of Phillips, the Fusus carinatus of Roemer, the Triton buccinoideum, the
Purpura filosa, the Murex versicostatus, and the Fusus corallensis of Buvignier, and, pro-
bably, the Fwsus nassoides and the Fusus nodulosus of Deslongchamps. All the species are
small, the largest scarcely equalling 10 lines in length.

The Fusus Thorenti d Archiac would appear at first sight to belong to ths genus; but
having examined the original specimens in the collection of Viscomte d’Archiac, we are
inclined to believe that the figure in the ‘Memoirs of the Geological Society of France’
(vol. v, plate 30, fig. 8), is taken from an imperfect shell, which is closely allied to, if not
identical with, the Zurbo pyramidalis of the same author.

BRACHYTREMA BUVIGNIERI. Plate V, fig. 7.

B. Testé conicd, turbinatd, apice obtuso; anfractibus 5 planatis, et costulatis; costis (14)
longitudinalibus, elatis, lineas transversas numerosas, elatas, distantes gerentibus.

Shell conical, turbinated, apex obtuse, whorls 5, flattened and costated ; costa longi-
tudinal, elevated, about 14 in a volution, and impressed by transverse lines: the lines are

GASTEROPODA. 25

numerous, distant, and elevated—a single one more elevated, being placed at the base of
each whorl. The longitudinal ribs are occasionally unequal, one unusually large sometimes
appearing, but not extending beyond the whorl, forming a varix after the manner of
Triton ; the columella is twisted, turned outwards at the base, and forms, with the outer
lip, a short oblique channel, which is not perceptible upon the back of the shell; the outer
lip is thin and dentated externally by the elevated transverse lines.

Locality. This species is moderately rare; it occurs in the coarse bed of planking
at Minchinhampton Common, and is seldom well preserved.

BRACHYTREMA TURBINIFORMIS. Plate IX,: fig. 35, 35a.

B. Testa turbinatd, ventricosd, spird elevata; anfractibus 4 angustatis, convexis, nodulato-
carinatis ; ultimo anfractu ventricoso, costulis longitudinalibus ; striis transversis numerosts,
impressis; apertura subrotundd, canal subnullo, columella rectd.

Shell turbinated, ventricose; spire elevated; whorls 4, narrow, convex, their sutures
deeply impressed, having a nodulated carina; the last whorl is large and ventricose, having
small longitudinal ribs crossed by numerous transverse strize; the aperture is nearly round,
the canal reduced to a mere notch; the columella straight.

This species is chiefly distinguished from its congeners by a greater dilatation of the last
whorl, which is much expanded transversely. Unfortunately the beds of planking, which
contain this and various other small univalves with ornamented surfaces, is of so coarse a
structure, and adheres to the shells with such tenacity, that it is not often that their features
can be distinguished. Length 6 lines.

Locality. Minchinhampton Common.

Family—Buccinipz.

PurpuroiwEa, Lycett. 1848.

Murex, sp., Sow. 1827.
Purrura, sp., Buvignier. 1843.
Purpurina, sp., D’Orb. 1850.

P. Testé turbinaté, spird elevatd, apertura non longiort, apice subacuto ; anfractibus
convexis, in medio tuberculatis, anfractu ultimo ventricoso ; bast truncatdé, apertura sub-
quadratd, superne acuta, inferne truncata, latd ; canali lato, recurvato ; columelld arcuatd,
rotundatd, levi, basi acuminata, incurvata ; labio effuso, in medio subdepresso, labro tenui
et sinuato, umbilico obtecto.

Shell turbimated ; spire elevated, not longer than the aperture, with a somewhat acute
apex ; whorls convex, nodulated in their middle part, the last whorl ventricose, the base

26 MOLLUSCA FROM. THE GREAT OOLITE.

truncated, the aperture subquadrate, acute above, widely notched at the base, but not
deeply nor recurved ; columella curved, and turning inwards at its base, which is pointed ;
it is rounded and smooth ; the inner lip is effuse, rather depressed in the middle, covering
an umbilicus; the outer lip is thin and somewhat sinuated.

This is one of the most remarkable of the Great Oolite genera of Univalves, and has
not as yet been found in any other than the oolitic rocks. It constitutes an addition to the
Purpurifera of Lamarck, or the Hnatomostomata of De Blainville. The following characters
in their combination will be found sufficiently to distinguish it from all other known genera:
the truncated base, the wide and shallow notch, the columella smooth, rounded, and curving
inwards, the concealed umbilicus, and the thin sinuated outer lip. The young shells are
delicately striated or grooved, the basal notch is scarcely formed, and they are perfectly free
from adherent shells. On the other hand, the full-grown shells are always more rugose ;
with advance of age their sulcations or other markings become irregular, or are nearly
obliterated, the basal notch becomes more important, and not unfrequently the whole
external surface becomes covered with adherent shells. It would even seem that those
encrusting shells were carried about by the animal during life. They are never found upon
the young shells, or within the aperture, upon the left lip, about the basal notch, or, in
fact, upon any part which was in contact with the soft parts of the animal. As the
Purpuroidea are found lying in every possible position, the absence of adherent shells upon
the parts in question may be held conclusive as to their period of attachment.

It will be seen, then, that the generic characters above enumerated acquire importance
only upon their being viewed in combination. Owing, perhaps, to a want of attention to
this circumstance, it may be that an undue value has been assigned to one or two cha-
racters, or to the inspection of ill-preserved specimens, or the want of a sufficient number
to exhibit their several phases of form and markings ;—to one or all of these causes of error
we may ascribe the fact, that one of our species has already been thrice figuréd and
described under two generic and three specific designations.

The beds of planking upon Minchinhampton Common are the productive site of this
genus. ‘The shells are clustered together over a small area. Originally the space was
about 100 yards in length and half that extent in breadth ; but from the rapid quarrying
of the stone, which there occurs in very large blocks, by far the greater portion is now
removed, and the genus has already become comparatively scarce. ‘T'wo other localities,
near and upon the same geological position, have furnished it, but very rarely, and in a bad
state of preservation. In the upper division of the Great Oolite near Minchinhampton
(from the white limestone upwards), the genus is likewise found occasionally over small areas,
and in considerable numbers; but, owing to the compactness of the investing limestone,
the shells can never be extricated except as casts. In this condition, with some small por-
tion of the shell preserved, they resemble the specimen figured in the ‘ Mineral Conchology,’
t. 578, fig. 4; but when entirely denuded of the crystalline shell, they have the aspect of
Natica, and without great care might be taken for that genus, the surface is smooth,

GASTEROPODA. 27

and retains only the faintest traces of tubercles ; the axial umbilicus is very conspicuous ;
and all trace of the wide basal notch being lost, the aperture resembles an entire-
mouthed shell. The hard limestone being much used for rough walls, it is upon these,
when partial disintegration has taken place, that the casts of Purpuroidea are to be found.
The genus has never been discovered lower than the planking.

PurpuromEa Mornavsia. Plate IV, figs. 1, la, 2, 3, 8a, 4.

Purpura MoreEausia, Buvignier. Mém. Soc. Philomath. Verdun, 1843, pl. 6, fig. 19,
p- 26.
PuRPURINA — D’Oré. Prod. Paleont., p. 357, 1850.

P. Testa turrité, globosd ; spird brevi, anfractibus 3—A, nodulosis vel spiniferis ; spinis
magnis, obtusis, im serie unicéd 7,8, aut 9 in ambitu; anfractu ultimo striato, striis regu-
laribus transverse subundulatis (obsoletis in etate seniort) ; aperturdé ampld, subquadratd ;
canali dilatato, leviter excavato.

Shell globose, spire prominent, whorls 3—4, angulated ; angles tuberculated ; tubercles
large, elevated, 8 or in others 7, upon a volution ; the last whorl ventricose ; the tubercles
increasing in size until they become large blunt spires; beneath the tubercles the surface
has numerous undulating closely-arranged encircling cost; the aperture is large and
widely truncated at its base; the inner lip is somewhat depressed in its middle part.

This is by much the most abundant, and at the same time typical species of the genus.
There may be considered to be two varieties, one having 8, the other only 7, spines in a
volution ; the latter variety has the spire more depressed, the aperture occupying three
fourths of the entire length of the shell. The elevated longitudinal swellings, produced by
the successive extensions of the outer lip in growth, sometimes interfere with the continuity
of the encircling ribs,—cause them to undulate, and occasionally obscure them altogether
hence, in the younger specimens, the ribs are more regular and distinctly marked. Very
rarely, indeed, individuals have been found which simulate P. nodulata, the lines of growth
being enlarged to imperfect ribs, which suddenly disappear, or are depressed at the place
where, in the species referred to, the second circle of nodules is situated; the spire also
becomes more elevated, which adds to the resemblance. In the figure given by Buvignier,
the inner lip is more flattened, or Purpura like, than might have been expected ; but the
figure altogether is executed in a very indifferent manner.

Locality. The vicinity of Minchinhampton is the only locality in which this remarkable
shell is known to have been procured in England. Buvignier mentions that M. Moreau,
of St. Mihiel, has found it in the Coral rag of that place, and likewise in the ferruginous
Oolite of Launoy.

28 MOLLUSCA FROM THE GREAT OOLITE.

PurpurorEA GLABRA. Plate IV, figs. 5, 5a, 6, 6a.

P. Testé turbinata, ovata; spird exserta ; anfractibus 5—6 angulatis, angulis tuberculos
10 gerentibus ; anfractu ultimo ventricoso, levi, basi truncata ; aperturd magna.

Shell turbinated, ovate; spire elevated; whorls 5—6 angulated; angles tuberculated ;
tubercles 10 im a volution; the last whorl ventricose, smooth, the base truncated; the
aperture large.

In the young state the spire is simply convex, without tubercles, which are only faintly
visible upon the last whorl. In every stage of growth the tubercles are less conspicuous
than in either of the other two species, and the surface of the last whorl is entirely destitute
of ribs and of a second circle of tubercles; the spire is smaller than in P. nodulata, but
more elevated than in P. Moreausia. The length of the aperture is three fifths of that of
the entire shell.

Locality. It accompanies the other congeneric forms in the Minchinhampton Great
Oolite, but is very much the most rare of them. The proportion of each species is probably
as follows: P. Moreausia, 50; P. nodulata, 5; P. glabra, 1.

PurpuROIDEA NopuLATA. Plate V, figs. 1, la, 2, 3, 4.

Mvrex Noputatus, Young and Bird. Geol. of Yorkshire Coast, p. 245, t. 11, fig. 3.
— TuBERosus, Sow. Min. Con., t. 578, fig. 4; but not t. 229, fig. 1, which isa
Tertiary shell.
Purpura Lapierrea, Buvignier. Mém. Soc. Philomath. Verdun, 1843, p. 27,
pl. 6, fig. 21.
PURPUROIDEA NopDULaTA, Lycett. Annals of Nat. Hist., 1848, p. 250.
Murex Tuserosus, Brown. Illust. Foss. Conch., p. 59, pl. 34, fig. 19.

P. Testé turbinatd, ovata ; spird easerta ; anfractibus 5—6 angulats ; angulis tuberculos
(9—11) plerumque elatiores gerentibus ; anfractu ultimo subventricoso, tuberculis binis
cincto, prope basin transverse carinato ; tuberculis inferioribus minoribus, approximatis et in
costulis longitudinalibus obliquis productis: aperturd magna subquadratda, lubro dextro
sinuato.

Shell turbinated, ovate ; spire elevated; whorls 5—6 angulated; the angles tubercu-
lated ; the tubercles usually elevated, 9, 10, or 11 in a volution; the last whorl ventricose,
encircled with two rows of tubercles ; those on the second row are much the smaller, and are
more closely arranged, and prolonged into longitudinal oblique ribs, which are sometimes
nearly obsolete ; below the ribs is a transverse keel, placed near to the base of the shell.
The aperture is of moderate size, the outer lip being much sinuated.

The first two or three whorls are convex, and destitute of tubercles; the tubercles
vary much in size in different specimens—when very much elevated they are com-
pressed laterally. In the young state, the apex of the spire is more acuminated, the surface

GASTEROPODA. 29

of the whorls has fine encircling striae, the second circle of tubercles is not formed, or is
merely rudimentary, and the longitudinal ribs beneath and basal carina are both absent ;
the last whorl has therefore a smooth aspect, which is in striking contrast with specimens of
advanced age. The length of the aperture in the adult shell somewhat exceeds that of the
spire; but the latter portion varies much in altitude, and occasionally exceeds the aperture
in length. Upon the whole, the aspect of this species varies so considerably, independently
of the changes produced by the stages of growth, that a considerable number are requisite
for its full elucidation. It accompanies P. Moreausia, but is much more rare, probably in
the proportion of about 1 to 10.

The figures given by Young, Sowerby, and Buvignier, present but a remote resemblance
to each other and to our figures, but there cannot be much doubt of their identity. Young’s
figure represents an individual with a spire rather depressed; that in the ‘ Mineral Con-
chology’ is from a mutilated specimen, little better than a cast. Buvignier’s figure is
hkewise imperfect, besides which, the artist appears to have represented the inner lip of a
true Purpura.

Locality. Minchinhampton Common.

This species has been found in Yorkshire only in the Coralline Oolite, where casts are
stated to be not unfrequent in the hard limestone. M. Buvignier’s specimen is from the
ferruginous oolite of Vieil-St.-Remy.

Lamily—CERITHIADE.
Crrituium, Adanson, 1757. Brug., Lam.

Shell elongated, tuberculated or costated, seldom smooth; spire pyramidal or cylin:
drical, composed of numerous volutions ; aperture subquadrate, terminated anteriorly by a
short canal, which is most frequently reflected outwards and backwards.

CHRITHIUM QUADRICINCTUM, Goldf. Plate IX, fig. 8.

CERITHIUM QUADRICINCTUM, Goldfuss. Petref., p. 32, t. 173, fig. 11.
—_ —_— Bronn. Index Paleont., p. 272.

C. Testa conicé, anfractibus (10—12) quadrigonis, cingulatis, cingulis superficialibus
quarterms granulatis ; granulis longitudinalibus seriatis.

Shell conical, spire obtuse, whorls (1O—12) rather convex ; encircled with four coste ;
the costa are granulated, so as to form a longitudinal series. The whorls are narrow,
the height scarcely exceeding one third of the transverse diameter; the largest specimens
do not exceed half an inch in length, and half of that length may be considered as the
average dimensions.

5

30 MOLLUSCA FROM THE GREAT OOLITE.

Locality. Itis by far the most abundant of the Great Oolite Cerithia, and may usually
be seen sprinkled over the blocks of planking at Minchinhampton Common ; but occurs
indifferently in all the shelly beds.

CreRITHIUM LIM@FORME, Jtém. , Plate VII, fig. 2.

CERITHIUM LIMEFORME, Roemer. 1836. Nordd. Oolith., p. 142, t. 11, f. 19.
— i a Goldfuss. Petref., ili, p. 33, t. 173, f. 17.
— — Bronn. Index Paleont., p. 269.

C. Testa turritd, .anfractibus (7—8) depressis, subplanis, cingillato-granulatis trilineatis,
granulis majusculis approaimatis costellas longitudinales formantibus, apertura ovata, canalt
brevi truncato.

Shell turreted, apex pointed, whorls (7—8) depressed, nearly flat, having transversely
nodulated coste, three in number upon each whorl; the nodules are nearly joined longi-
tudinally, presenting the appearance of longitudinal ribs in the young shell; but in a more
adult state the upper row becomes more distinctly separated from the other two, which
latter have sometimes an additional row of smaller granules between them.

This shell, as compared with C. guadricinctum, would appear to be much more rare ;
but as it requires a close inspection to distinguish them, some uncertainty must exist.

Locality. Tt accompanies the above-mentioned species in all the shelly beds. Its length
does not exceed 3 lines.

Crritaium sexcostatum. Plate VII, fig. 3, 3a.

C. Testa turritad, levi, anfractibus convewiusculis, costatis ; costis (6B—7) longitudh-
nalibus, levigatis, rotundatis, angustatis, rectis; apertura ovatd ; caudd obsoleta.

Shell turreted, smooth; whorls rather convex, costated; coste (7—6) longitudinal
smooth, rounded, narrow, and straight; aperture ovate. The mbs do not form a con-
tinuous line upon the volutions, a complete circle occupying more than 6, but less than 7
costee, whose upper extremities scarcely reach the sutures of the whorls; the whorls are
rather high, their junctions are deeply impressed, the last whorl being equal in length to
two fifths of the entire shell. Axis 73 lines.

Locality. The white stone of Bussage has furnished our only example.

CERITHIUM PENTAGONUM, Archiac. Plate IX, fig. 22.

CERITHIUM PENTAGONUM, Archiac. Mém. Soc. Géol. Fr., tom. 5, p. 354, t. 31, f. 6.
-- — D’Orb. Prod. Paléont., p. 303.
a —_ Bronn. Index Paleont., p. 271.

GASTEROPODA. 3l

C. Lesté subulata, apice acuto, anfractibus (10—11) planatis, pentagonalis, longi-
tudinaliter costatis; costis 5 in ambitu, perpendiculariter continuis, elatis, subacutis ; striis
numerosis transversis impressis ; canali minima.

Shell subulate, apex acute, whorls (10—11) flattened, pentagonal, longitudinally
costated ; costae continuous, perpendicular, elevated, rather acute, 5 in a volution; strize
numerous, transverse ; canal very small.

This elegant, symmetrical, and remarkable species has the junctions of the whorls strongly
marked; it ranks among the choicest of our smaller shells. Axis 9 lines, transverse
diameter 2 lines.

Locality. It has been found only in the planking of Minchinhampton Common and
white stone of Bussage. We are not aware that more than four examples have been
discovered.

CERITHIUM STRANGULATUM, Archiac. Plate IX, fig. 18.

CERITHIUM STRANGULATUM, Archiac. 1843. Mém. Geol. Soc. France, v, p. 382, t. 31,
figs. 1, a, b.
— —- D Orb. Prod. Paléont., p. 303.
— — Bronn. Index Paleont., p. 274.

C. Testé minutd, subcylindricd, pupeformi, costatd ; anfractibus subplanatis 7, trans-
versim sulcatis; sulcis 4, penultimo 5; costis (6) rectis, elatis et longitudinaliter continuis
ab apice ad anfractum penultimum; apertura constrictd, parvd, obliqud subrotundd ; canal
nullo.

Shell minute, subcylindrical, or pupzeform, costated ; whorls nearly flat (7), transversely
suleated, sulci 4, and 5 upon the penultimate whorl; coste 6, straight, elevated, and
longitudinally continuous from the apex to the penultimate whorl; aperture contracted,
small, oblique and somewhat rounded ; no canal.

This little shell has prominent lines dividing the transverse sulcations; the costal
elevations, although strongly marked upon the first three or four whorls, are not dis-
tinguishable upon the latter two; these whorls have also a greater proportional length than
the others, their breadth but little exceeding their height ; the junctions of the whorls are
not very strongly marked, the apex of the spire is obtuse, the aperture much contracted,
rounded, and oblique or pupzform. .

The obtuse spire, flattened whorls, and fewness of the cost, will distinguish this from
C. bulimoides, Deslongchamps, and C. Roémeri, Goldfuss ; to which in other respects it has
some resemblance. We have considered it a variety of C. strangulatum, Archiac, although
in that species the apex is pointed, the general breadth is greater, and the costz are
continued even to the base of the shell.

Locality. Ancliff, Wiltshire; Eparcy, France.

32 MOLLUSCA FROM THE GREAT OOLITE.

CERITHIUM TENNANTI. Plate IX, fig. 20.

C. Testa turritd, acutd, conicd, anfractibus numerosis, angustatis, tricinctis ; carinis
tribus, elatioribus, striis numerosis longitudinalibus impressis; bast planatd, canali
brevissimd.

Shell turreted, acute, conical, whorls numerous, thrice cinctured; the bands elevated,
and impressed with numerous longitudinal strize ; base flattened, canal obsolete.

‘The transverse keels are equal, narrow, and elevated, one being mesial, the others close
to the anterior margin of the whorls; the figure is perfectly regular, and the whorls
narrow ; the aperture and canal are very short. i

Locality. Ancliff.

Named after Prof. J. Tennant, from whose interesting collection of Oolite Fossils this
species is figured.

Crrituium Roissi, Arch. sp. Plate VII, fig. 14, 14a.

TuRRITELLA Rotsstl, Archiac. 1843. Mém. Soc. Geol. Fr., vol. v, p. 380, t. 30, f. 2.
— — Bronn. Index Paleont., p. 1336.
Cuemnitz1a Rotssy1, D’Orb. Prod. Paléont., p. 298.

C. Testé turritd subconicd, levi, apice acuto ; anfractibus paucis, planatis; suturis vix
tumidulis; cauda brevi subrectd.

Shell turreted, subconical, smooth; apex acute; whorls few, flattened; the sutures slightly
tumid; canal short, and nearly straight.

A very, short or conical species, the diameter of which through the last whorl is upwards
of half the entire length of the shell; a longitudinal section displays a columella of great
thickness, the internal cavity bemg small.

Locality. Rare in the Great Oolite of Minchinhampton Common. LEparcy, France.

Nerinza, Defrance. 1825.

Shell turreted, either conical or cylindrical, consisting of numerous whorls ; aperture
subquadrate, having an anterior and posterior short canal; columella, with one or more
folds ; outer lip, with one or more folds, which are continued through the length of the
shell ; columella umbilicated im the conical, solid in the cylindrical species.

Nerina#a Voxrzi, Desi. Plate VII, figs.11, lla; var? figs. 7, 7a.

Nera Vourzi1, Deslongchamps. 1842. Mém. Soc. Linn. Normandie, vol. vii, pl. 8,
fig. 34.
— — D’Orb. Prod. Paléont., p. 298. (Not N. Voltzii, D’Arch.)

GASTEROPODA. 33

NV. Testé turrito-conicd, spiré angulo 18°—22°, anfractibus subplanis inornatis; colu-
mellé crassd, prius solid denique perforata, plicas duas parvas, remotas gerente; labro
dextro intus uniplicato, apertura rhomboidal.

Shell elongated, conical, smooth ; in its young state there is usually a slight depression
round the lower part of each whorl, this is gradually lost in the larger whorls, which are
quite flat; but specimens may be found in which all the whorls are slightly convex. The
columella is solid in the young shell; but usually becomes perforated about an inch below
the apex ; there is great variety in this respect in different specimens, the perforation some-
times commencing within half an inch from the apex, while other shells, an inch and a half
long, may be found quite solid. The spiral angle also varies from 20° to 22° in different
specimens ; in some instances the sides of the shell are straight, in others the lower part is
more cylindrical than the upper; m some few instances the lower part of the shell enlarges
more rapidly than the upper, in which case the perforation of the columella is unusually
large. Thus the species varies in its external form, from a neat, regular shell to a
very clumsy one. ‘The aperture is rhomboidal, its height being half as much again as its
width, ending below in a short canal. There are three internal folds, viz.: one on the outer
hp, near to the base of the whorl, which is insignificant at the aperture, but long and strong
in the inner whorls; another, thick and blunt on the columella, a little below the preceding;
thirdly, one small and blunt on the top of the whorl. These folds are very constant in
form, and serve to distinguish the species readily.

wututabamele. fe Gs ROOF to. OB”
ase Pamelor ee week irae as Leo tO. LaU.
Length, 1 inch to 23 inches.

In the young state, or when the axis does not exceed 10 or 12 lines, the aspect is so
dissimilar of this protean shell, that a particular description of that condition is necessary :—
It is taper and pointed, the volutions are convex, very narrow, an individual of 9 lines
having as many whorls. The sutures are very deeply depressed, the shell is altogether
delicate and fragile, but perfectly regular. Specimens exceeding 10 lines increase dispro-
portionally in the height of their whorls ; they become more flattened, the sutures are less
strongly defined, the shell acquires a considerable increase of thickness, and the whole is
changed.

Locality. This specimen occurs in every stage of growth and throughout the entire
thickness of the formation in Gloucestershire; its habits were gregareous—the shelly
weatherstones more especially contain it in great numbers.

Nerin#a (Trocwaria) Evprsu. Plate VII, fig. 6, 6a.

? Ceritu1um Derrancit, Deslongchamps. Mém. Soc. Linn. Normandie, vol. vii, pl. 8,
fig. 36.

N. Testé turritd, conicd, anfractibus (10) concavis, angustatis, lineis transversis cinctis

34 MOLLUSCA FROM THE GREAT OOLITE.

cum aliis minoribus alternatis, suturis carinatis, carinis elatis et levigatis, basi planulatd,
canali brevissimo; apertura subquadrata. '

Shell turreted, conical, excavated ; whorls (10) concave, narrow, with numerous trans-
verse very fine lines, alternating with others still more faintly impressed ; the sutures are
carinated, the carine elevated and smooth, the base flattened, the canal short. Aperture
subquadrate.

The general aspect of our species approaches near to the Cerithium Defrancii of
M. Deslongchamps, whose figure however is less conical, and the concavity of the whorls
is much less. These differences, however, are only such as may pertain to varieties of the
same species. It is rare; and the few examples which have occurred to us are composed
entirely of crystalline carbonate of lime, which does not allow of the internal characters
being fully determined; as far as we can observe them, the outer lip is simple, and the
columella plicated with one fold, and the upper portion of the volution has a very slight
fold. This shell belongs to the subgenus Zrochalia, Sharpe; but to the species having the
columella solid and not hollow.

+Locality. The upper portion of the shelly beds near to Minchinhampton and
Chalford.

NERINZA DUFRENOYI, Arch. sp. Plate VII, fig. 8, 8a—8e.

CrritHium Durrenoyl, Archiac. 1843. Mem. Soc. Géol. Fr., vol. v, pl. 31, figs. 3, 4.
— — D’Orb. 1850. Prod. Paléont., p. 303.

NV. Testé parva, cylindrico-subulatd ; anfractibus latis, planatis, costulis cinctis, et nodu-
latis; cingulis 4 aut 5, inequalibus dense-nodulatis, cingula infra suturam valde elatd, et
levigatd, sine nodulis. Anfractibus lineis perpendicularibus, interstitialibus dense et
tenuissime instructis. Apertura elongatd, columella solidd, plicis duabus? parvis; plicd
externa unicd, magna.

Shell small, cylindrical, or subulate ; the whorls wide, flattened, encircled with costa,
which are nodulated ; the encircling bands are 4 or 5, unequal and closely, but sometimes
imperfectly, nodulated ; the band nearest to the upper suture the largest and most elevated,
it is nearly smooth, and without nodules. The surface of the volutions has also very
closely-arranged fine perpendicular lines visible upon the interstices of the cinctures. The
aperture is elongated and narrow; the columella solid, with two small folds; the outer lip
has a single, much larger fold. '

The perpendicular length of the whorls is nearly equal to their transverse diameter ; the
sutures are strongly marked. ‘The usual length of this species does not exceed an inch,
the number of volutions in large specimens not exceeding ten. ‘The coarseness of the
Great Oolite rock is not favorable to the preservation of the more delicate features of this
pretty and fragile species, so that im the greater number of instances the surface of the

—s ee,

GASTEROPODA. 35

whorls is nearly smooth. It occurs in all the shelly beds of the formation in Minchin-
hampton district, and may be discovered in every quarry, sometimes in great numbers.
The smallness of the object, and the state of preservation, renders it difficult to obtain
a good section of the interior; the folds upon the columella have been but imperfectly
disclosed, but there is little doubt that they are as above described ; the aperture is usually
more narrow than is represented at fig. 82.
Locality. Minchinhampton Common ; Eparcy, France.

NERIN#A STRICKLANDI. Plate VII, fig. 9, 9a.

NV. Testa cylindrico-subulata, anfractibus latis, planatis, superne leviter convexis, suturis
profundis impressis; cingulis scabris aut crenulatis, numerosis et approximatis, superne
evanescentibus : apertura, plicisque tgnotis.

Shell cylindrical or subulate ; whorls wide, numerous, flattened, or very slightly convex
on their upper portions, their sutures strongly marked; the whorls are encircled with
numerous, closely-arranged, scabrous, or crenulated lines, which are nearly obsolete upon
their upper portions: aperture and plicae unknown.

The character of the surface much resembles Cerithium tortile, Deslongchamps ; but the
whorls in that shell are much more convex and narrow; in the present species the length
of the whorls perpendicularly is about equal to their transverse diameter.

Locality. The Stonesfield slate on the borders of Minchinhampton Common has
furnished our specimens ; they have occurred rarely, and only in fragments ; when perfect,
the length must be considerable.

Nerina puncrata, Voltz. Plate VII, fig. 10, 10a, 4, ¢.

Nerin@a Punctata, Voltz. and Bronn. Jahrb., 1836, p. 559, t. 6, fig. 23.
— — Bronn. Index Palzont., p. 803.

N. Testé turrito-conicd, anfractibus sub-gradatis, cingulatis, cingulis binis ternisve nodu-
losis ; columella soliddé, biplicatd, labro deatro uniplicato.

Shell elongated, conical, with a regular spiral angle of about 18°; whorls flat, pro-
jecting at the upper part beyond the whorl above, and thus giving a step-like outline to the
shell; ornamented with two or three transverse finely-knotted rmgs: columella solid.
Three internal folds, viz.: one strong sharp fold on the middle of the outer lip; one smaller
fold on the columella, a little lower than the former, and a blunt thick fold on the top of
the whorl near to the columella. Aperture rhomboidal, rather higher than wide.

This is a more regular and elegant shell than JV. Vol¢ziz, to which it is so nearly allied,
that worn specimens of the two species may easily be confounded: in that case the
N. punctata may be distinguished by its step-like outline, flatter base, and longer and

36 MOLLUSCA FROM THE GREAT OOLITE.

sharper folds on the columella. With WV. elegans (Thurm.) it may perhaps be identical, in
which case that name must be adopted for it: until this is decided we must call our shell
NV. punctata, as it is clearly the species so designated by Voltz.

Sutural angle, about 92°

Basal angle, about 120°

Length, from 1 to 2 inches.

Locality. ound in the shelly beds near Minchinhampton, and more frequently in the

quarries to the north of the vale of Chalford.

Nerin@a FunicuLus, Desi. Plate VII, fig. 12, 12a, 6.

NERINHA FUNICULUS, Deslongchampse 1842. Mém. Soc. Linn. Normandie, vol. vii,
p. 186, t. 8, figs. 30—32.
— CYLINDRICA, Deslongchamps. UL. c., t. 8, fig. 33.
CERITHIUM BLaINVILLII (?), Deslongchamps. L. «., t. 8, fig. 35.
Nerinm®a Frunicutosa, D’Orb. Prod. Paléont., p. 298.

N. Testé turritd, longissima; anfractibus superioribus concavis, transverse striatis,
inferioribus subplanis, aliis ad suturas tumescentibus, aliis vie prominulis; columella solida,
triplicatd, labro dextro uniplicato. (Deslongchamps, 1. c.)

Shell very long and taper, but differing in the spiral angle in different specimens from
8° to 12°; the upper whorls are concave, with a strong projection at the suture, variously
ornamented with from 5 to 10 transverse ribs of unequal fineness, one or two of which (in
very well-preserved specimens) are seen to be composed of small knobs; the lower whorls
become gradually flatter and smoother, and finally lose all traces of ribbing: columella
solid. Four’internal folds, viz.: one strong, thick fold on the outer lip, rather below the
middle of the whorl; two on the columella, of which the lower sharp and well-defined is
situated below that on the outer hp, and the upper faint and sometimes hardly visible, is
placed opposite to the upper edge of the outer fold; and one sharp and long fold on the
top of the whorl, close to the columella.

Nerinea cylindrica of Deslongchamps appears to be a tapering variety of the same shell,
in which the upper fold on the columella is ill-developed, or perhaps imperfectly seen.

This species is also closely allied to WV. fibula, NV. Goodhalli (not Sowerby’s species), and
NV. clavus of Deslongchamps, all of which are probably one species : it differs from them in
the greater concavity of the whorls, the transverse ribbing, and the presence of the upper
small fold on the columella. It has probably been confounded with JV. fasciata of Romer—
a species which sadly wants revision.

Sutural angle, about 105°.
Basal angle, about 120°.
Length, up to 5 inches, but rarely exceeding 3 inches.

Locality. It is tolerably abundant in the shelly beds near Minchinhampton ; but owing
to its great fragility, large specimens can rarely be procured entire.

GASTEROPODA. 37

Creritetua. Vov. Gen.

C. Testd turritd, spird acuta, subulatda, anfractibus planis, marginibus sepissime sulcatis ;
anfractu ultimo amplo ; apertura elongata, obliqud (canali (?) brevissimd) columella levigata,
rotundata ad basim subreflewd.

Shell turreted, spire acute, subulate, volutions flattened, their margins usually sulcated ;
the last whorl large, aperture lengthened and oblique, canal very short ; columella smooth,
rounded, and slightly reflected at the base; outer hip thin.

This genus is constituted to receive several species of subulate univalves, usually smooth,
but sometimes sculptured longitudinally, which seem to be equally removed from Zerebra
on the one hand, and Cerzthium on the other; from the genus Fwsus they are still more
remote. ‘The increased size of the last whorl, together with the elongated narrow aperture,
detach it from the Cerithig ; neither has it the decided twist of the columella, which we
find in Zerebra; the base never terminates in a notch, but in a narrow, very short,
channel, which is turned slightly forwards and outwards ; the whorls are generally flattened,
the length of the spire exceeding that of the aperture. }

The Ceritelle, from their individual number and variety of species, constitute an
important group in the Great Oolite univalves. The delicacy of the outer lip is such, that
a specimen with that part perfect has scarcely ever been obtained, the remaining portion
usually giving to the base the aspect of a short channel, slightly directed outwards. It is
certain, however, that in several of these species the base of the aperture is very narrow,
and slightly twisted, approaching nearly to the channelled form, a character which, together
with that furnished by the spire, separates it sufficiently from the <Acteonine properly so
called, and to which some of the species have a slight resemblance. We have, therefore,
provisionally arranged these shells in this part of the series, until the characters of the
aperture are more fully developed.

CERITELLA acuta. Plate V, figs. 17, 17a, 18, 18a.

C. Testa turritd, levigatd ; spird elatd, acuta ; anfractibus (6) convexiusculis ; apertura
obliqua angustatd, cauddé recurvd brevi.

Shell turreted, smooth; spire elevated, acute; whorls (6) rather convex, aperture
oblique, narrow ; canal recurved and short.

The figure of this species varies considerably. The young shells are usually the most
subulate. The length of the last yolution is generally half that of the entire shell. Axis
10 lines, transverse diameter 4 lines.

Loculitys It is numerous in all the shelly beds in the vicinity of Minchinhampton.

6

38 MOLLUSCA FROM THE GREAT OOLITE.

CrERITELLA UNILINEATA, Sow., sp. Plate V, fig. 13.

BUCCINUM UNILINEATUM, Sow. 1825. Min. Con., t. 486, figs. 5, 6.
— — Morris. 1843. Cat. Brit. Foss., p. 139.
PURPURINA UNILINEATA, D’Orb. 1850. Prod. Paléont., p. 302.

C. Testé parva, ovato-elongatd, gibbosd ; spird acutd ; anfractibus (7—8) angustatis,
superne planis et subangulatis.

Shell small, ovately elongated, gibbose, ; spire acute; whorls (7—8) narrow, flattened
in their upper portions or subangulated.

This little gibbose shell has a spire about equal in length to the last whorl; the whorls
are bevilled near to their upper junctions, or slightly depressed, which gives the appearance
of a line or furrow encircling them. Axis 43 lines, transverse diameter 2 lines; but the

Ancliff specimens are usually smaller.
Locality. The white stone of Bussage has furnished only one specimen near Minchin-

hampton ; but it is much more abundant at Ancliff.

CERITELLA PLANATA. Plate V, figs. 14, 14a.

C. Testé turritd, acuta ; anfractibus angustatis, numerosis, planis ad basim unilineatis ,

apertura et cauda ut in C. acutd.

Shell turreted, acute; whorls narrow, numerous, flattened; a single encircling line is
placed at the lower part of each whorl, a little above the suture; aperture and canal as in
C. acuta. Axis 44 lines, transverse diameter 23 lines.

Locality. Rare: the specimen figured is from the white stone of Eastcomhs, in the

parish of Bisley.

CrriteLLA Sowers. Plate V, fig. 16.

C. Testé turritd, subfusiformi, acuta ; anfractibus (7—8) conveaiusculis, infra suturam
unilineatis ; apertura obliquda, elongata ; cauda brevi.

Shell turreted, subfusiform, acute; whorls (7—8) slightly convex, with a transverse
line beneath the suture; aperture oblique, lengthened ; canal short.

‘This species varies considerably in the elevation of the spire. Axis 8 lines, transverse

diameter 3 lines.
Locality. Vt occurs in the upper portion of the shelly beds, both north and south of

the vale of Brimscomb. It 1s rare. -

GASTEROPODA. 39

CERITELLA MITRALIS. Plate V, fig. 15.

C. Testé conicd, apicé acuminata, anfractibus (7) angustatis, planis, marginibus sub-
tumescentibus ; aperturd parvd, obliqud ; canali brevi.

Shell conical, apex acute, whorls (7) narrow, flattened, their upper margins slightly
turned; aperture small, oblique; canal short.

This species is unusually short and conical. Axis 5 lines, transverse diameter 3 lines.

Locality. The planking of Minchinhampton Common, where it is rare.

CERITELLA conica. Plate V, figs. 10, 10a, 104, 10c.

C. Testa turritad, acuta ; anfractibus angustatis planis (8) ; costis longitudinalibus, a
dextro ad sinistram obliquis ; apertura angustatd, canali obliquo.

Shell turreted, acute; whorls narrow, flattened (8), with longitudinal oblique. ribs,
passing obliquely from right to left ; aperture narrow, canal oblique.

The upper margin of each whorl has a slight encircling rib, which is united to the
oblique costee. The character of the markings in this species resembles C. gidbosa ; but in
that species, although the whorls are equally numerous, the spire is very small, and the
canal is almost obsolete. The length of the last whorl is two fifths of the entire shell.
Axis 63 lines, transverse diameter 3 lines.

Locality. The planking of Minchinhampton Common and white stone of Bussage
have furnished it but rarely.

Cerireia arpposa. Plate IX, ODT:

C. Testa parva turritd, spird mediocriter elatd, apice acuto, anfractibus planatis, angus-
tatis et angulatis, longitudinaliter costatis ; costis numerosis, a dextro ad sinistram obliquis ;
anfractu ultimo, magno ; apertura obliquda, angustata et elongatd.

Shell small, turreted; spire moderately elevated; apex acute; whorls flattened at the
sides, narrow, and angulated at their upper portions; longitudinally costated; cost
numerous, directed obliquely from right to left; the last whorl large; aperture oblique,
narrow, and elongated.

The angle of the whorls is slightly thickened and prominent; the cost are distinct
immediately beneath it, but are not discernible upon the lower portion of the whorls. The
length of the aperture is equal to the remaining portion of the shell. The specimen figured
is rather more gibbose than usually obtains, for the proportions vary, but in point of size
there is no considerable difference. It is somewhat rare, and occurs in the soft shelly
Oolite which underlies the planking. Axis 3 lines.

Locality. Minchinhampton Common.

a i tc nt rte ee ee ee eee iii, ie

_ 40 MOLLUSCA FROM THE GREAT OOLITE.

CrrRITELLA Lonetscata, Buv. sp. Plate IX, fig. 14.

PLEUROTOMA LONGIscATA, Buvignier. Mem. Soc. Philom., Verdun, 1843, pl. 6, fig. 8.

Testa parva, turritd, elongata ; apice acuto; anfractibus (9—10) subplanatis ; costis
longitudinalibus rectis numerosis, carinatis ; carind unicd marginali ; apertura angustata ;
cauda subrecta.

Shell smooth, turreted, elongated; apex acute; whorls (9—10) rather flattened, with
longitudinal, straight, numerous ribs; and a single encircling smooth carina upon the
upper margin of the whorls; aperture narrow, canal straight, short. Axis 3 lines.

Locality. This little species accompanies its allied forms in the soft shelly Oolite
beneath the planking of Mmchinhampton Common. It is very rare.

CERITELLA RISSOIDES, Buv.sp. Plate IX, fig. 7.

? PLEUROTOMA RISSOIDES, Buvignier. Mém. Soc. Philom., Verdun, 1843, pl. 6, fig. 9.

Testa parva, turrita ; spird mediocri elata ; apice acuto ; anfractibus angustatis, posticis
carinatis, carina rotundata ; costis longitudinalibus, rectis, subincurvis ; anfractu ultimo
elongato ; apertura angustatd.

Shell turreted, spire moderately elevated, apex acute, whorls narrow, carimated at their
posterior margm; carina rounded; coste longitudinal, straight, or shghtly curved; last
whorl elongated ; aperture narrow. Axis 2 lines.

Locality. This pretty minute species is usually found in the soft shelly Oolite beneath
the planking of Minchinhampton Common. It is somewhat rare.

Family—N aTiciD&.
Natica, Adanson. 1757. Lam.

The species of WVatiea in the Great Oolite are divisible into two groups; one the
Natica proper, the others we have arranged in the sub-group uspira, a name suggested by
Agassiz, for those species which have the spire more or less elevated, and the volutions
distinct.

The Natice, though consisting of a considerable number of species, have, with one
exception, furnished but a small number of individuals; and those belonging to the sub-
group Huspira are all rare in the Great Oolite.

GASTEROPODA. Al

NATICA.

Shell subglobose, thick, smooth ; spire poimted, more or less elevated, of few volutions ;
aperture large, oblique, ovate, entire ; columella lip oblique, thickened, the umbilicus being
nearly covered by a deposition of shelly matter upon the columella; outer lip simple,
smooth.

Natica INTERMEDIA. Plate VI, figs. 1, 1a.

NV. Testé ovata, spird elatd, anfractibus (5) conveais, angustis, superne planis ; averturd
ovato-elongatd, basi lata.

Shell ovate, spire elevated, whorls (5) convex, narrow, flattened above ; aperture ovately
elongated, base wide.

The general contour of this shell approaches nearer to Natica adducta, Phillips, than
any other Great Oolite species which we have examined. Its position is intermediate to
that species and our Natica Stricklandi, which latter species is more elongated. In all
these shells the upper portion of the whorls is horizontal; but in WV. adducta it is even
depressed as it approaches the suture, forming a narrow channel. JV. intermedia is more
ovate, or less globose, than JV. adducta. In that species the transversal is equal to the
longitudinal diameter ; but in VV. ixtermedia the dimensions are as follow: Length 2 inches,
breadth 1 inch 7 lines.

Locality. The planking of Minchinhampton Common has supplied the few specimens
we have met with.

Natica Grannis, Goldf. Plate VI, fig. 12.

Natica GRANDIS, Goldfuss. Petref., iii, p. 118, t. 199, fig. 8.
— Bronn. 1848. Index Paleeont., p. 783.

NV. Testa globoso-depressd, spird subexsertd, anfractibus convexiusculis, ultimo anfractu
ventricoso ; margine depresso ; apertura semilunari ; umbilico tecto.

Shell globose, depressed ; spire little elevated; whorls rather convex, their margins
rather depressed, the last volution ventricose ; the aperture large, semilunar ; the umbilicus
covered by a callosity of the lip.

We have only met with three examples of this species: two of these were obtained
from the upper limestone beds, the other from the planking. ‘The general form is more
ventricose, and the last whorl more expanded, than either of our other species. The nearest
approximation to it is the atica adducta, Phillips, of which, possibly, our shell may only
exhibit a more advanced stage of growth ; but as the spire of that species is more produced,
and as our shell perfectly agrees with the species figured by Goldfuss, we prefer, for the
present, to retain his designation.

Locality. Minchinhampton.

42 MOLLUSCA FROM THE GREAT OOLITE.

Natica Stricknanpi. Plate XI, figs. 24, 24a.

NV. Testé ovata, spird elata, anfractibus convexiusculis, superne rotundatis, suturis sub-
depressis ; apertura oblique ovata ; basi angustatda.

Shell ovate, spire elevated, whorls rather convex, rounded above, their sutures slightly
depressed ; aperture oblique and ovate; base attenuated.

The length of the aperture scarcely exceeds half of the entire shell; the whorls, which
are not numerous, are moderately wide, and somewhat flattened at their base; the apex is
rather obtuse, and the general form is more cylindrical than is usual with shells of this
genus, the largest transverse diameter being only equal to the length of the last and penul-
timate whorl. We have only obtained two specimens which occurred in the soft shelly
Oolite underlying the planking, but, judging from casts, we should be inclined to believe
the upper portion of the formation likewise contains it. It has been named as a trifling
- tribute of respect to H. E. Strickland, Esq., one of the few English geologists who, of late
years, have contributed to our knowledge of the Oolitic system.

Locality. Minchinhampton. |

Natica Formosa. Plate VI, fig. 10.

NV. Testé ovato-elongatd, spird elatd, anfractibus (5) convewis, ultimo anfractu oblique
ventricoso ; apertura magna ovatd ; basi rotundatd, labro sinistro excavato.

Shell ovately-elongated, spire elevated, whorls (5) convex, the last whorl ventricose and
oblique ; the aperture large, ovate, the mner lip excavated, the base rounded.

We were at first disposed to refer this species to Watica elegans, Sowerby, but an
examination of additional specimens has convinced us of its specific distinctness. As com-
pared with that species, the spire is always much larger, and less angulated, and the
aperture bears a much less proportion to the entire length, its longer diameter scarcely
amounting to three fifths of the entire length of the shell. It occurs both in the planking
and upper portion of the formation, but is somewhat rare. Length 26 lines, breadth
20 lines. The apex, when perfect, is more acute than our figure represents.

Locality. Minchinhampton.

Natica Tancrepi. Plate VI, fig. 11.

NV. Testé ovatd, spird elatd, anfractibus (5) angustatis in medio subangulatis ; apice
obtuso ; anfractu ultimo subcylindrico, permagno ; aperturd obliqud angustatd ; basi sub-
acuminata.

Shell ovate, spire elevated, whorls (5) narrow, somewhat angulated in their middle
portions ; the apex is obtuse, the last whorl is very large, and subcylindrical ; the aperture
oblique and narrow, the base somewhat pointed.

GASTEROPODA. 43

The narrowness of the base, narrow subangular whorls, obtuse apex, and subcylindrical
figure of the last whorl, are the prominent features.

It has been named in compliment to Sir Thomas Tancred, Bart., the founder of the
Cotswold Naturalists’ Club.

Locality. The fine specimen figured was obtained in the hard white limestone of the
upper portion of the Great Oolite formation near Minchinhampton, but it likewise occurs
in the planking, being rare in both situations.

Narica GLososa, Roem. Plate VI, fig. 14.

Narica GLoBosa, Roemer. 1836. Nordd. Oolith., p. 156, pl. 10, f. 9.
— — Bronn. 1848. Index Paleont., p. 783.

NV. Testa globosd, obliqua, ovato-orbiculari, hemisphericd; spird latd, prominuld ;
apertura subreniformi ; umbilico amplo.

Shell globose, oblique, ovately orbicular, hemispherical ; spire large, but not much
elevated; aperture kidney-shaped ; umbilicus large.

All our specimens have been obtained from the upper or limestone portion of the Great
Oolite ; we have, consequently, been able to obtain only portions of the shell. The figure
approaches so near to some of the casts of Purpuroidea Moreausia, that it is difficult, in
the absence of nodules, to distinguish them. Our species is, however, more depressed, and
the preserved portions of the shell are thicker than in the Purpuroidea ; but we should
always expect to find some traces of nodules in well-preserved casts of the latter genus.
Length 14 lines, breadth 16 lines.

Locality. Minchinhampton.

Natica NERITOIDEA. Plate VI, fig. 4.

NV. Testa oblique-ovatd; spird parva, obtusd, depressd ; anfractu ultimo elongato ;
apertura angustatd, obliqua ; labio interno calloso.

Shell smooth, oblique, ovate; spire small, depressed, and obtuse, the last whorl
elongated and narrow atthe base; the aperture narrow and oblique, the inner lip
thickened.

Two examples, with the shell partially preserved, are our authority. They are remark-
able for the rounded and depressed form of the spire, which gives it a truncated aspect : it is
likewise turned to one side simulating a Nerita. ‘The form of the aperture and base is more
narrow or contracted than any other Great Oolite species. Length 13 lines, width 9 lines.

Locality. A bed of sandy limestone, about 100 feet above the Fullers-earth.

44 MOLLUSCA FROM THE GREAT OOLITE.

Natica VERNEUILI, Archiac. Plate VI, figs. 6, 6a, 7, 7a.

NaTICA VERNEUILI, Archiac. 1843. Mem. Soc. Geol. France, t. 5, p. 378, pl. 30, fig. 3.
— — Bronn. 1848. Index Palzont., p. 788.
= _ D’Orb. 1850. Prod. Paleont., p. 299.

N. Testé subhemispherica, spird elatd, anfractibus (5) angustis et convexiusculis, apice
acuto ; anfractu ultimo per magno, ventricoso ; aperturd magna semilunari; basi latd et
rotundatda.

Shell subhemispherical, spire elevated, whorls (5) narrow and slightly convex, apex of
the spire acute, last whorl very large and ventricose, aperture large, semilunar, base wide
and rounded.

The planking has supplied the only good specimens of this rare species. It would
also seem to occur in the calcareo-arenaceous beds of the upper portion of the formation,
judging by the aspect of casts. Length 23 lines, breadth 22 lines.

Locality. Minchinhampton. LEparcy, France.

Natica Micuxini, Archiac. Plate VI, figs. 2, 2a, 3, 3a.

Natica Micuexini, Archiac. 1843. Mem. Geol. Soc. France, t. 5, p. 377, pl. 30, fig. 1.
= — Bronn. 1848. Index Paleont., p. 785.
— — D’ Orb. 1850. Prod. Paleont., p. 299.

NV. Testé ovata, spird parva, apice submamillato ; anfractu ultimo elongato, basi lata ;
apertura superne angustaté ; labro interno calloso convexiusculo.

Shell ovate, spire small; apex submamillated, last whorl elongated, its base wide;
aperture narrow above ; lip somewhat thickened, straight, and convex.

The straight border of the inner lip, its convexity, and the minute spire, sufficiently
characterise it. ‘The spire consists of 5 or 6 whorls, of which the first two or three form a
minute mamillated apex. Our figures sufficiently represent the varieties of form, of which
the more elongated is the most common. ‘The planking contains it not unfrequently ; and
some beds in the upper limestones contain numerous casts, which can scarcely be referred
to any other shell.

Length of the globose variety 18 lines, width 16 lines; length of the elongated variety
18 lines, width 13 lines.

Locality. Minchinhampton. LEparcy and Sancerre, France.

Natica amBieva. Plate VI, fig. 5.

? CassIs EPARCYENSIS, Archiac. 1843. Mém. Soc. Géol. France, tom. v, p. 385,
pl. 31, fig. 10.
? ACTEONINA EPARCYENSIS, D’ Orb. 1850. Prod. Paléont., p. 299.

GASTEROPODA. 45

NV. Testi hemisphericad, spird parva, depressd ; apice acuto; anfractibus angustatis,
planis, anfractu ultimo ventricoso ; apertura elliptica.

Shell hemispherical, spire small, depressed; the apex acute; whorls narrow and
flattened, the last whorl ventricose; aperture of moderate size, and elliptical; inner lip
rounded.

The general figure approaches to globular, except at the base of the spire, which is
flattened, and only the small volutions rise above the wide and flattened upper surface of
the last whorl; the base is comparatively narrow; the inner lip is gracefully curved, but
not apparently thickened, nor is there any trace of an umbilical fissure. One specimen only
was obtained in the planking. It is imperfect about the outer lip, and scarcely half the
dimensions of the shell figured by D’Archiac. Length 10 lines, breadth 10 lines.

Locality. Minchinhampton ; Eparcy, France.

Sub-Genus—Kusrira, Ag.

Shell smooth, ovate; spire elevated; of few whorls, which are angulated, the angles
sometimes taking the form of a carina; less frequently the last whorl has a second carina,
or the carma becomes nodulous or tuberculated ; aperture entire, elliptical, modified by the
angle of the whorl; base wide, rounded; pillar lip smooth and excavated, outer lip thin
and smooth.

The Great Oolite shells referable to this genus are all rare. One of them, however
(#. canaliculata), though rare in this formation, is abundant in the middle division of the
Inferior Oolite.

Huspira cANALicunata.* Plate XI, fig. 23, 23a.

E. Testé oblonga, spiré sub-exsertd, apice acuto, anfractibus angulosis, angulis acutis;
anfractibus superne profunde canaliculatis, inferne sub-convexis ; anfractu ultimo obliquo,
basi attenuata; apertura ellipticd, fissuré umbilict angustata.

Shell oblong, spire but little elevated, apex acute, whorls angulated, the angles acute,
the upper portion of the whorls deeply channelled, their lower portions rather convex, the
last whorl oblique, its base attenuated; aperture elliptical, the umbilical fissure narrow.
Several obscure encircling lines may be traced upon the middle of the last whorl. The
specific characters of this shell are so strongly marked that it will not readily be mistaken
for any other; several specimens have been extracted from the limestone beds in the upper
portion of the Great Oolite; but m the middle beds of the Inferior Oolite in Gloucester-

1 Although we have provisionally arranged this and the four following species under a sub-genus of
Natica, they present considerable affinities to the Palaeozoic genus, Scalites (Hall), in the lines of growth
having the appearance of a slight fissure where the angle occurs in the volution.

7

AG MOLLUSCA FROM THE GREAT OOLITE.

shire it is much more common. Length 14 lines, breadth 12 lines, length of aperture
10 lines, breadth 6 lines.
Locality. Minchinhampton.

Kuspira sHARPEI. Plate XI, fig, 22.

EL. Testa oblonga; spird elatd, apice acuto, anfractibus angulosis; angulis acutis et
prominentibus, superne tabulatis, inferne planis; aperturd magnd, labro sinistro eacavato et
umbilicato.

Shell oblong, spire elevated, its apex acute, volutions angulated, the angles acute and
prominent, the upper surfaces of the whorls nearly flat, but rising a little towards the
suture, the lower portion flattened; aperture large, inner lip excavated with an open
umbilicus.

This species most nearly resembles #. canaliculata, but in the present shell the spire
is very much more elevated; the upper surfaces of the whorls are not channelled, and their
lower portions are not convex.

Locality. Minchinhampton. It is very rare, and has been found only in the planking.
Length 18 lines, breadth 15 lines.

Named in compliment to D. Sharpe, Esq., F.R.S.

HKusPira PYRAMIDATA. Plate VI, fig. 8, 8a.

EL. Testé ovata, spird elata, pyramidatd, apice acuminato, anfractibus (A) angulatis ;
angulo in carinam obtusam producto; anfractibus superne tabulatis, inferne planis, apertura
ovata, bast rotundata, fissurad angusta.

Shell ovate, spire elevated, pyramidal, apex pointed, whorls (4) angulated, the angle
forming an obtuse cara; upper surface of the whorls tabulated, lower flattened, aperture
ovate, base rounded, umbilical fissure narrow.

In this species the spire and aperture are nearly of equal length, beneath the angle of
the body whorl a slight depression is perceptible; the flattened upper area of the whorls
is narrow compared with the other contemporaneous species.

Locality. Minchinhampton. It occurs in the planking, and is rare.

Evsprra coronata. Plate VI, fig. 9.

LL. Testa subglobosd, spird elata, anfractibus (4—5) angulatis, angulis nodulatis ; nodulis
aumerosis ; anfractibus superne tabulatis, inferne subplanis ; anfractu ultimo globoso, carinis
duobus nodosis cincto ; aperturd magna ellipticd, bast rotundatd ; umbilico parvo.

ai i

GASTEROPODA. Ai

Shell subglobose, spire elevated, whorls (4—5) angulated, the angles nodulated, the
nodules being small and numerous; the whorls are flattened above and beneath the angle ;
the last whorl is globose, and has two encircling nodulous carinz, with a depression between
them ; the aperture is large and elliptical; the base rounded and wide; the pillar lip with
an open umbilicus.

This may be regarded as an aberrant form of Awspira, in which the carina becomes
nodulous ; the nodules, however, are not prominent nor large, those of the second carina
being smaller, more numerous, and rather indistinct. There is also a slight sulcus between
the carne which are connected together by obscure elevations, but these merely appear as
slight plications. The general form bemg globose, and the carina broken into nodules,
renders its aspect less angular than is usual in the genus. Length 21 lines, breadth
19 lines.

Locality. Minchinbampton : the planking has furnished our only example.

KusPIRA SUBCANALICULATA. Plate VI, fig. 13.

EL. Testé oblonga ; spira sub-exserta ; anfractibus (4) angulosis, marginibus subdepressis,
superné tabulatis, inferné subconvexis; anfractu ultimo obliquo; apertura subtrigond;
obliquia, bast angustata ; labro interno calloso umbilicum obtigente.

Shell oblong; spire but little elevated; whorls (4) angulated, their margins rather

depressed, flattened above the angle, and rather convex beneath; the last whorl oblique ;
aperture subtrigonal, the last whorl oblique, the base narrow; the inner lip thickened, and
covering an umbilicus.
_ Unfortunately we possess only one specimen of this little shell, which was obtamed im
the planking ; it may possibly be a young variety of #. canaliculata, in which the upper
portions of the whorls may become channelled with advance of growth, and the general
figure more globose; the appearance of the imner lip and. umbilicus, however, are certainly
different ; and we, therefore, prefer to keep this as a distinct species. Length 8 lines,
breadth 7 les.

Locality. Minchinhampton.

Fumily—PYRAMIDELLIDA.

Eviima, Risso. 1826.

Turreted, smooth, pyramidal; spire long, consisting of numerous whorls; apex acute,
slightly tortuous; aperture oval, rounded anteriorly; outer lip slightly thickened ; colu-
mella smooth.

48 MOLLUSCA FROM THE GREAT OOLITE.

Evurma communis. Plate IX, figs. 21, 21a.

EF. Testé turrité, levigatdé ; spird regulari, obtusd ; anfractibus subplanis in cetate
juniori, etate progrediente convexis ; apertura ovata ; labro tenut.

Shell turreted, smooth; spire regular, obtuse; whorls rather flattened in the young
state, but with advanced age more convex; aperture ovate; lip thin.

When young the shell is much more flattened and obtuse ; but in all stages of growth
the junctions of the whorls are strongly marked—the oldest specimens have the lines of
growth strongly developed upon the last volution. The contrast between the peculiar
flatness and almost conical figure of the young shells and older specimens which have lost
their apex is so great, that without the assistance of intermediate forms they would
probably be regarded as distinct species. The length never exceeds an inch.

Locality. This is decidedly the most common univalve of the Great Oolite, and occurs
in all the shelly beds, more especially in the soft shelly Oolite beneath the planking at
Minchinhampton Common.

Evurima prema. Plate IX, fig. 1.

EL. Testé levigatd, turritéd ; spird obtusé ; anfractibus paucis, subplanis ; apertura sub-
contracta.

Shell smooth, turreted; spire obtuse; whorls few, nearly flat; aperture oblique, and
somewhat contracted laterally.

The last whorl is large, its length being half of that of the entire shell; the obtuseness
of the spire, fewer volutions, nearly cylindrical figure, and obliquity of the aperture,
separate it from /. vagans.

Locality. A single specimen is all we have met with: it occurred in the white stone

of Bussage.

Euuima vacans. Plate IX, figs. 3, 4.

EB. Testé turritd, levi, elatd; spird acutd, anfractibus paucis subplanis; apertura
ovata ; labro dextro subexpanso.

Shell turreted, smooth, elevated; spire acute; whorls few, high, and nearly flat ;
aperture ovate ; right lip somewhat expanded.

The last whorl is nearly equal in length to all the others together.

Locality. Vt occurs in the shelly planking rarely; and a few casts have also been
obtained in the upper portion of the formation, east of Minchinhampton.

GASTEROPODA. 49

EHvtima supetososa. Plate IX, fig. 6.

LE. Testa levi, ovato-conicd ; spird subcontorta ; anfractibus convexis, angustatis, anfractu
ultimo subgloboso ; apertura obliqua, ovatd.

Shell smooth, ovately conical; spire rather contorted; whorls convex, narrow, the last
whorl subglobose ; aperture oblique and ovate.

A small globose species, the spire of which is rather angular, its length being somewhat
less than that of the last whorl.

Locality. Itis rare, and occurs in the soft shelly Oolite of Minchinhampton Common.

Cuemnitzia, D’ Orbigny. 1839.

Shell turreted, elongated, not umbilicate ; volutions numerous, frequently costulated ;
aperture oval or angular, anteriorly large, retracted posteriorly; columella straight and
smooth ; outer lip thin and smooth.

Cuumnirzia Lonspauer. Plate VIII, figs. 13, 13a.

C. Testd turritd, apice acuto, levigato ; anfractibus in medio profundeé constrictis vel
sulcatis, suturis vie impressis ; apertura, elongato-ovatd, superne constricta.

Shell turreted, elongated, acute, smooth; whorls deeply constricted, or sulcated in their
middle part; sutures of the whorls sometimes scarcely distinguishable ; aperture elongated
and ovate, narrow posteriorly.

For the first four volutions the mesial depression is but shghtly marked; but it gradu-
ally increases in depth, the last two or three whorls being deeply grooved. Several oolitic
species approach this shell, more especially the Melania lineata of the Mineral Conchology
and the JZ. procera of Deslongchamps; in the latter species, however, the concavity of the
whorls is always very slight, and is sometimes not appreciable. Axis 3 inches 3 lines ;
transverse diameter 10 lines; length of aperture 10 lines; breadth of aperture 5 lines.

Locality. Our species is moderately rare; it has been found only in the planking of
Minchinhampton Common. |

Named after W. Lonsdale, Esq., F.G.S., whose valued contributions to Geology,
especially among the oolitic series, are well known.

CHEMNITZIA SIMPLEX. Plate VII, fig. 15.

C. Testé magna, turritd, elongata, lev; anfractibus conveais, suturis profunde impressis,
apertura obliqud ovata ; columella marginatd, rotundatd, subrecta ; labro interno effuso.

Shell turreted, elongated, smooth; whorls convex, the sutures deeply impressed, aperture
oblique, ovate ; columella marginated, rounded, nearly straight ; inner lip effuse.

50 MOLLUSCA FROM THE GREAT OOLITE.

In this large species the volutions are high and globose, the base of the shell is rather
contracted. ;
Locality. The few specimens found, have been obtained from the planking ; the fine
example figured is from the hard weatherstone of Bisley Common.

Cuemnitzia Hampronensis. Plate VII, figs. 1, la.

C. Testé elongato-conicd, spird mediocriter obtusd; anfractibus (10—11) planis et
costatis; costis longitudinalibus (20—22) numerosis, rectis, vel subfleauosis; aperturd parva,
ellipticd.

Shell conical, but much elongated ; spire, with the apex, somewhat obtuse; whorls
(10—1]) flattened and costated ; costz numerous, perpendicular, but slightly bent in the
middle, inclining from left to right ; aperture small, and elliptical.

The whorls are narrow, their axis being equal only to half their transverse diameter ;
the coste are narrow, and moderately elevated in young specimens, but after seven
volutions have been formed, became much more faintly marked, and finally are obsolete ;
the less subulate form and very narrow whorls separate it from Zerebra vetusta (Phil. Geol.
York., t.9, f.11), to which the markings upon its surface have a near resemblance.
Axis of largest specimen 15 lines; transverse diameter 5 lines.

Locality. Minchinhampton Common and vicinity, where it is moderately rare: it is
usually found in the soft oolite beneath the planking.

Cuemnitzia Lucxensyi. Plate VII, fig. 4.

C. Testé parvd, laevigata, subulatd ; anfractibus numerosis, subplanis, superné conveais,
anfractu ultimo symmetrico.

Shell small, smooth, subulate, acute; whorls numerous, narrow, flattened, except upon
their upper portions, where they are convex; the last whorl symmetrical.

This small species approaches in figure two contemporaneous species, viz., the young
state of Werinega Voltzii and of Fulima? communis; from the former of these it is dis-
tinguished by the greater flatness of the whorls; from the young state of the latter by the
much greater number of whorls, more subulate form, and acute apex. Axis 33 lines.

Locality. Minchinhampton Common.

CHEMNITZIA WETHERELLU. Plate VII, figs. 5, 5a.

C. Testa cylindrico-elongata ; anfractibus numerosis (12) subconvexis, longitudinaliter
costatis ; costis (14) rectis obtusis ; apertura parvd, ovata.

Shell cylindrical, elongated, whorls numerous (about 12), somewhat convex, longi-
tudinally costated ; costee perpendicular, obtuse, closely arranged, about 14 in a volution ;
aperture small, ovate.

GASTEROPODA. 51

A small, slender species, with closely-arranged costa, which are rather large, but not
much elevated; the sutures of the whorls are strongly marked ; it is rare, but has occurred
in more than one of the shelly beds. Axis 10 lines; transverse diameter 2 lines.

Locality. Minchinhampton Common.

This species is named in compliment to our kind and liberal friend, N. T. Wetherell,:
Hsq., F.G.S.

CHEMNITZIA VARIABILIS. Plate VIII, figs. 7, 7a, 6.

C. Testa turritd, subulatd ; anfractibus conveciusculis, transversim striatis, plus minusve
erenulatis, longitudinaliter costatis, costis curvatis circa 12 in ambitu; costis interdum inter-
ruptis nodulosis ; apertura ellipticd obliqué ; columellé marginata.

Shell turreted, subulate ; whorls rather convex, transversely striated, striz more or less
longitudinally costated, costee curved, about 12 in a volution ; ribs sometimes obsolete, and
replaced by nodules ; aperture elliptical, oblique ; columella marginated.

Specimens differ in the convexity of the whorls, those which are most convex have the
ribs shortest, or reduced merely to nodules placed upon the upper border of each whorl: in
all specimens the costz become obsolete before reaching the base of each whorl. Occa-
. sionally upon the same specimen the ribs degenerate into nodules, only the smaller whorls
are then costated. This species was first mistaken for Melania undulata (Deslongchamps) ;
but in that shell the sides of the volutions are flat, the costae are more numerous, and
extend to the junction of the whorls, and have no curvature except in the last one;
they are likewise less subulate than in our species. Axis 5 lines; transverse diameter
13 lines.

Locality. It is abundant in all the shelly beds of the Great Oolite, near Minchin-
hampton. .

CHEMNITZIA PHASIANOIDES. Plate IX, fig. 5.

C. Testé ovato-subcylindricd, spird elatd, apice obtuso ; anfractibus (5) planis, anfractu
ultimo subcylindrico, elongato ; apertura obliqua ; labro dilatato.

Shell ovately-subcylindrical, spire elevated, apex obtuse, whorls (5) flattened, the last
whorl subcylindrical, elongated ; aperture oblique ; outer lip dilated.

This species has a considerable resemblance to Hulima vagans, but the spire is much
shorter, the whorls are fewer, and the apex is more obtuse ; the aperture is rather narrow, its
length being two fifths of the entire shell.

Locality. The planking of Minchinhampton Common has furnished our specimens.

52 MOLLUSCA FROM THE GREAT OOLITE.

Family—LitTToRINIvz.

Rissoina, D’ Orbigny. 1842.

Shell turreted, acuminated; spire long, consisting of several whorls; aperture oval,
rather pointed at the two extremities; outer lip thickened, emarginated; columella

rounded, straight.

Rissoina DupLicaTa, Sow. Plate IX, fig. 10.

Rissoa DupLicaTa, Sow. 1829. Min. Con., t. 609, fig. 4.
_ — Brown. Illust. Foss. Conch., t. 38, figs. 14, 15.
— Morris. Cat. Brit. Fossils, p. 161.
a — Bronn. Index Palzont., p. 1092.

Rissorna DupLicaTA, D'Orb. Prod. Paléont., p. 297.
— — D'Orb. Pal. Frang. Terr. Jurass., t. 237, figs. 1, 2.

A. Testé parva turritd, acutd ; anfractibus (6) ia medio angulatis; costulis longi-
tudinalibus angustatis, remotiusculis; carind unicd in medio anfractuum sitd; anfractu
ultimo, costulis numerosis longitudinalibus rectis ornato, carind evanescente.

Shell small, turreted, acute; whorls (6) angulated, with remote, narrow, longitudinal
coste ; each whorl has a low carina, situated a little beneath its middle part; the last
whorl has very numerous small, longitudinal and straight ribs; the carina is scarcely dis-
cernible upon the last whorl. The costze upon the last whorl are twice as numerous as
upon the spire, and the figure of the whorl is nearly cylindrical, or slightly biangulated ;
and the carina becomes obsolete; the Rissoa unicarina of Buvignier, and the Fusus cari-
natus of Roémer, approach very nearly to this species, with which they may possibly
be identical ; judging from the descriptions, however, there are certain points of distinction
which appear to separate them from our species. Length 2 lines.

Locality. Ancliff and Minchinhampton Common ; at the latter place it is very rare,
and found only in the beds of planking.

Rissorva optievata, Sow. Plate IX, fig. 19.

Rissoa OBLIQUATA, Sow. 1829 Min. Con., t. 609, fig. 3.
— — Brown. Illust. Foss. Conch., p. 79, t. 38, figs. 19, 20.
— — Bronn. Index Paleont., p. 1093.

Rissomna optiquata, D’Oré. Prod. Paléont., p. 297.

R. Testé turritd, turbinatd, acutd ; anfractibus (6—7) convexis et costatis ; costis a

dextro ad sinistram obliquis.

GASTEROPODA. 53

Shell turreted, turbinated, acute; whorls (6—7) convex and costated ; coste oblique,
directed from right to left.
~The costee are rather more elevated than in &. acuta, and the entire figure is more
turbiniform, the whorls being much more convex. Length from 23 to 3 lines.
Locality. Ancliff; also very rarely at Minchinhampton Common, in the planking.

Rissoina acuta, Sow. Plate IX, fig. 9.

Rissoa acura, Sow. 1829. Min. Con., t. 609, fig. 2.
a — Brown. Illust. Foss. Conch., p. 79, t. 38, figs. 25, 26.
— — Bronn. Index Paleont., p. 1090.

Rissorna acuta, D’Orb. Prod. Paléont., p. 297.

Rh. Testé parva, turritd, acuta; anfractibus conveciusculis 6, costulis angustatis subre-
motis longitudinalibus; apertura ovatd; labio dextro expanso.

Shell small, turreted, acute; whorls (6) slightly convex, with narrow, rather remote,
longitudinal ribs ; aperture oval; right lp expanded.

The surface is nearly smooth; the longitudinal ribs, or rather lines, scarcely affecting
the evenness of the surface ; it is the most slender example of the genus which the Great
Oolite has produced. Length, 3 lines.

Locality. Ancliff; and very rarely Minchinhampton Common, in the planking.

RIssoINA CANCELLATA. Plate IX, figs. 12, 12a.

R. Testa turbinata, turritd, acuta; anfractibus convewis (8), angustis, transverse costatis;
costis (6—7) inequalibus, liners longitudinalibus decussatis ; apertura lata. :

Shell turreted, turbinated, acute; whorls convex (8), narrow, transversely costated ;
costee (6—7) unequal, decussated by longitudinal lines; aperture wide.

The upper cost of each whorl are smaller and more approximated than the lower ; the
convexity of the whorls is chiefly upon their lower portions; the fine longitudinal lines
crossing the narrow encircling coste give to the surface a cancellated aspect ; the aperture
is acute above, rounded beneath.

Locality, The soft Oolite beneath the planking of Minchinhampton Common furnished

this pretty little shell, of which we have not seen another example.

RissoINA TRICARINATA. Plate IX, fig. 13.

R. Testd parva, turbinatd, acuté; anfractibus convexis; tricarinatis; carinis crenulatis;
carind superiore apud suturam positd; aliis in medio et approximatis; anfractu ultimo ad

basem lineis tenuissimis notato; aperturd parvd, suborbicularc.
8

54 MOLLUSCA FROM THE GREAT OOLITE.

Shell small, turbinated, acute; whorls very convex, and thrice carinated; carine
crenulated, the upper one placed near to the suture; the others about the middle of the
whorl, and near together; the last whorl has near to its base very fine encircling lines; the
aperture is small, and nearly orbicular.

In this minute shell the largeness and roundness of the carinz, and the great convexity
of the whorls are the most prominent features.

Locality. We have procured two specimens from the white stone of Bussage ; but in |

this, and probably other instances of minute shells, the small number known may indicate
rather our defective observation than the true relative numbers which they present.

Rissoina? Lavis, Sow. Plate IX, fig. 16.

Rissoa Lavis, Sow, 1829. Min. Con., t. 609, fig. 1.
— — Brown. Illust. Foss. Conch., p. 79, t. 38, fig. 12.
— — Bronn. Index Paleont., p. 1092.

R. Testé parva, turritd, levi, subcylindricd; anfractibus (6) subplanatis; anfractu
penultimo, et ultimo subcylindrico; aperturd parva, obliqua.

Shell small, turreted, pointed, smooth, and subcylindrical ; whorls (6) rather flattened ;
the last whorl, and also the penultimate whorl, are nearly cylindrical; aperture small and
oval, oblique. Length 23 and 3 lines.

Locality. Ancliff; also very rarely at Minchinhampton Common, where it has been
found in the planking.

This species scarcely exhibits the anterior notch characteristic of Rissoina.

Pacopus, Gray.

Sub-genus—AMBERLYA.

P. Testi turritd, turbinatd, apice acuto; anfractibus superné planis, infra conveais et
nodulatis; anfractu ultimo ventricoso; apertura ovatd, integra, labio interno calloso umbili-
cum vie obtigente; suturis profunde impressis; columella nulla.

Shell turreted, turbinated, apex acute ; whorls flattened above, convex, and nodulated
beneath, the last whorl ventricose ; aperture ovate, entire ; inner lip thickened, and nearly
covering a small umbilicus; sutures deeply impressed ; no columella.

The whorls are received into the concavity of those which succeed, the latter at their
junctions being slightly overwrapped by the former, after the manner of Scalaria; the
aperture is oval and oblique; the outer lip thin; the figure varied somewhat according to
the stage of growth, the last one or two volutions in adult specimens becoming more tumid
than the others ; in such examples, therefore, the spire acquires a slightly concave figure.

GASTEROPODA. 55

This shell may be considered to form only a section of Jzttorina, agreeing in the
general characters with the genus Pagodus of Gray, with which, probably, the discovery of
more perfect specimens may assimilate it.

AMBERLEYA (Pacopus) Noposa. Plate V, fig. 19.

TEREBRA NODOSA, Buckman. 1845. Geol. of Cheltenham, p. 102.

A. Testé turritd, ventricosd; spird elatd, apice acuto; anfractibus (6) infra nodulosis,
nodulis numerosis superné apud suturam cingulo nodulorum minorum ornatis; anfractu
ultimo basi costulis obscuris tribus cincto,

Shell turreted, ventricose; spire elevated ; apex acute ; whorls (6) convex on their lower
portions, and nodulated; the nodules closely arranged, and forming a small belt near to
the base of the whorl; another, much smaller and indistinct, circle of nodules encompasses
the whorls upon their upper portions near to the suture; the last whorl has at its base
‘three indistinct, narrow, encircling costz.

The number of nodules gradually increases in each volution, the last whorl having

about 18; the last two volutions are very ventricose, which give to the spire a slightly
concave figure; in the younger state, consequently, the figure is more slender than in the
adult. Our two specimens, which are of different stages of growth, present the following
proportions : — Adult, Axis 24 lines, transverse diameter 15 lines, length of aperture 11
lines, breadth of aperture 8 lines. Young state. Axis 16 lines, transverse diameter 9
lines, length of aperture 6 lines, breadth 43 lines.
Locality. Tt is very rare, the planking of Minchinhampton Common has furnished five
examples, and several imperfect casts have been obtained in the Stonesfield slate at another
place in the same vicinity: these casts have enabled us to ascertain the absence of a central
columella.

Oés. The specimen submitted to the artist was rather imperfect at the base of the
aperture, which, together with the position, give it the aspect of a regular notch at that
part of the shell.

Family—NERITID&.

Nerita, Linn. 1738.

Shell semiglobose ; spire short, sometimes not produced, consisting of few volutions ;
aperture large, semilunar; outer lip thick, inner lip thickened, usually flattened, and
striated or dentated at its inner edge.

The fossil species of Werita, from the Great Oolite, may be divided into the three
following sections, as dependent on the character of the inner lip :—

D6 MOLLUSCA FROM THE GREAT OOLITE.

Srcr. 1. Inner lip smooth.

N. Testé crassa, subhemisphericd ; spird parvd obliqua, depressa ; anfractibus paucis,
carinatis; apertura semilunari; labio dextro crasso, labio interno planato, amplo.

Shell thick, subhemispherical ; spire small, oblique, depressed ; whorls few, carinated ;
aperture semilunar ; outer lip thick and smooth; inner lip flat, broad, and smooth, without
notch or strie.

NERITA CANCELLATA. Plate XI, fig. 15, 15a.

N. Testé crassa, hemisphericd; spird parvd, depressd, obtusd; anfractibus (3) carinis
tribus cancellatis; carinis obtusis, striis longitudinalibus decussatis, et lineis inequalibus
et irregularibus cinctis ; apertura transverse oblonga.

Shell thick, hemispherical; spire small, obtuse, depressed; whorls (3), with three carine,
cancellated ; carine obtuse, decussated with longitudinal striz: the last whorl has also
irregular, unequal, encircling lines, which form, with the longitudinal striz, a cancellated
surface ; aperture transversely oblong ; inner lip very wide.

The most frequent aspect is that of a very rugose, depressed Nerite, with large, obtuse
carine and intermediate sulcations ; the distinctly cancellated surface is observable only in
the younger examples. The first and second carine are placed near together; between
these and the basal carina is a large surface, with encircling lines crossing the striae.
Portions of coloured surface are sometimes observed upon the carinz and upper portion of

the last volution.
Locality. Jt is moderately rare at Minchhampton Common and Bussage.

Nerita rucosa. Plate XI, fig. 17, 17a.

hk. Testé hemisphericad; spird parva, depressad; anfractibus (2 vel 3) carinato-striatis ;
ultimo anfractu subangulato, carinis tribus (carind mesd majore), et striis profundis longi-
tudinalibus plus minusve crebris; coloribus fuscis sepé pictis; labio interno, lato, planato.

Shell hemispherical; spire small, depressed; whorls (2 or 3) carmated and striated ;
the last whorl subangulated, having three carinze, of which the middle one is the most’
prominent and rounded; the last whorl has, also, longitudinal, deeply-marked strize, more
or less closely arranged, and not unfrequently marked with colours, arranged into two
broad encircling bands, separated by the mesial carina.

The longitudinal striae might sometimes, with more propriety, be termed costa ; when
the coste are large and distant the carine are likewise most prominent, and occasionally
both conditions may be observed in the growth of the same specimen—the smaller

-GASTEROPODA. 57

examples being such as usually have the most widely-separated longitudinal lines or striz.
The surface markings vary so considerably that they may be conveniently described under
the three following aspects :— .

a. Ribs elevated and separated ; carinze smooth and prominent.

4’. Surface with longitudinal closely-arranged plications, but no distinct ribs ; plicee
impressed with very fine longitudinal lines.

c’. In which the characteristics of the two former varieties are sometimes exhibited
upon the same specimen, in which case the carinz are imperfect, or, in lieu of them, there
are slight depressions or furrows.

The most common aspect is that of the variety a. It is one of the most generally-
noticed univalves of the shelly beds. Very rarely all traces of ribs and plications are
wanting, the surface is then shining, smooth, and highly coloured. The dimensions vary
from that of a duck-shot to the largest-sized pea.

Locality. Minchinhampton Common. In all the shelly beds of the district.

Nerita costutata, Desh. Plate VIII, figs. 6, 6a,6,¢c. Plate XI, figs. 18, 18a, 6.

NERITA cosTATa, Sow. 1824. Min. Con., t. 463, figs. 5, 6.
— — Phillips. Geol. of Yorkshire, vol. i, t. 11, fig. 32.
a — _. Brown. Ilust. Foss. Conch., p. 91, t. 44, figs. 1, 2.
— costunata, Desh. 1838. Lam. Anim. sans Vert., 2d Edit., vol. viii, p. 617.
— — D’ Orb. 1850. Prod. Paléont., p. 299.

N. Testé parva; spirdé obliqud depressd, minutd, vie elatd; anfractu ultimo superne
planato, costis longitudinalibus, numerosis, subundatis, et approximatis ornato.

Shell small; spire oblique, depressed, minute, scarcely elevated; the last whorl
flattened upon its upper portion, and covered with costae, which are longitudinal,
numerous, closely arranged, and slightly waved; the aperture is very large, the imner lip
very wide and flat.

The absence of carinze at once distinguishes this little shell from our Nerzta rugosa, for
one variety of which it might otherwise be mistaken. It has not been found in the
Minchinhampton Great Oolite, but occurs occasionally in the Inferior Oolite of that district.
Axis 2 lines. 7 |

Locality. Anchff; Stonesfield. nf. Ool., Yorkshire.

Sxcr. 2. Inner lip convex. Neridomus.

N. Testé laevigata, ovato-globosd; spird parva, obliqué; anfractu ultimo permagno;
apertura ovata, vel semilunari; labio eaterno crasso; labio interno crasso, convexo et
levigato. .

Shell smooth, ovately globose; spire small, oblique; the last whorl very large; aperture
ovate, or semilunar ; outer lip thick ; inner lip thick, convex, and smooth.

58 MOLLUSCA FROM THE GREAT OOLITE.

NeERITA HEMIsPHARICA, Roemer. Plate XI, fig. 16, 16a; 14, 14a.

NERITA HEMISPHHRICA, Roemer. 1836. Nordd. Oolith., p. 156, t. 10, fig. 7

NV. Testé levigata, transversé ovali-hemisphericd; spird parvd, prominuld; apertura
semilunari; labio interno magno, convexo et incrassato.

Shell smooth, transverse, ovately hemispherical ; spice: small; aperture semilunar ; inner
lip large, convex, and incrassated.

The surface of this species varies considerably ; the younger specimens being smooth,
and not unfrequently exhibiting portions of colouring in dark, encircling lines: the older 1
specimens are rendered rugose by numerous large plications of growth. It is not
uncommon, being found in all the shelly beds, more especially in the coarse planking.

Locality. Minchinhampton Common.

Nerita MINUTA, Sow. Plate XI, figs. 19, 19a.

NERITA MINUTA, Sow. 1824, Min. Con. t. 463, figs. 3, 4.
— — Desh., 1838. Lam. Anim. sans Vert., 2d Edit., vol. viii, p. 617.
— — DOrb. 1850. Prod. Paléont.,sp. 299.
— puLLA, Roemer. 1836. Nordd. Oolith., p. 155, t. 9, fig. 30.
— ovata, Roemer. Nordd. Oolith., p. 156, t. 10, fig. 6.
— Mats, Buvignier. 1843. Meém. Soc. Phil. Verd., t. 5, figs. 18, 19.

N. Testé parva levigaté; spird obliqud easertd et minutd; anfractu ultimo coloribus
hineatis undulatis sepissimé picto.

Shell small, smooth; spire oblique and minute; the last whorl most commonly exhibits
undulating-coloured lines, which occasionally coalesce, and are very irregular.

This little shell is a longer oval figure than both Werita hemispherica (Rém.) and
Neritina Cooksont (Desl.); the latter little species, with which it nearly agrees in size, is
more globose, and has a larger, more prominent, and less oblique spire than JV. Pudla.

LV. minuta occurs abundantly in all the shelly beds; its surface is very smooth and shining;
the most frequent size is that of duck shot ; the longer diameter not exceeding two lines.

Locality, Minchinhampton Common and neighbouring district.

Scr. 3. Inner lip notched. Neritopsis, Grateloup. 1840.

NV. Testé crassa, neritiformi, ovato-globosd; spird parvd, obliqud, anfractu ultimo
inflato, costis numerosis cincto; apertura suborbiculari, labro eaterno incrassato et levigato,
latio interno concavo, sulco lato margine excavato,

Shell thick, neritiform, ovately-globose ; spire small, oblique; the last whorl inflated,
encircled with numerous cost; aperture suborbicular; the outer lip thickened, but smooth;
the inner lip concave, with a wide notch upon its inner border.

GASTEROPODA. ~ 59

Neritopsis striata. Plate XI, figs. 13, 13a.

NV. Testé ovata; spird elatd; anfractibus tribus, convewis; anfractu ultimo costis nume-
rosissimis crebris cincto, costis subundulatis; aperturd ampla, ovata.

Shell ovate ; spire elevated ; whorls (3) convex ; the last whorl encircled with numerous
and closely-arranged cost, which slightly undulate; aperture large and ovate.

The costa are narrow, but slightly elevated, the interstitial spaces being so narrow as
to appear like strize ; hence, in badly-preserved specimens, the costa can scarcely be dis-
cerned ; the spire is small, moderately prominent, and has its surface distinctly sculptured
in good examples: the specimen figured is rather beneath the average size.

Locality. Minchinhampton Common, where it occurs somewhat rarely in the soft,
shelly oolite which underlies the planking.

NeRiTopsis suLcosa. Plate XI, fig. 12.
? NERIvTA suLcosa, Archiac. 1843. Meém. Soc. Géol. Fr., vol. v, tab. 28, fig. 8. (Non Brocchi.)

NV. Testa ovata; spird parvé; anfractibus tribus vel quaternis, convexis, sulco lato
spirali superné instructis; anfractu ultimo permagno, cingulis inequalibus, numerosis,
et magnis ornato.

Shell ovate; spire small; whorls (3 or 4) convex, with a wide, encircling sulcus upon
their upper portions; the last whorl very large, with numerous, unequal, and large
encircling bands.

The encircling ribs extend only upon the last volution, their inequality and large size
give to the surface a rugose aspect; the sulcus upon the upper part of the last whorl is
without coste ; the specimen figured is of the largest dimensions.

Locality, Minchinhampton Common, where it occurs somewhat rarely in the shelly
beds of coarse planking.

Pinzouus, G. B. Sowerby, 1823.

Shell conical, with a subcentral upright vertex; base concave, with a thin margin
and tumid centre; aperture small, within the margin of the base, sublateral, semilunar, its
outer lip prominent, the inner one crenulated ; spire internal, very short.” —Sowerdy.

60 MOLLUSCA FROM THE GREAT OOLITE.

Pinnotus piicatus, Sow. Plate IX, figs..36, 36a, 4, ¢.

Pitnotvs piicatus, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 1—4.
— — Sow. Min. Con., t. 432, figs. 1—4.
_ — Bronn. Leth. Geogn., p. 392, t. 27, fig. 6.
— —_ Brown. Ilust. Foss. Conch., p. 92.
— — D’ Orb. 1850. Prod. Paléont., p. 299.
— — Bronn. Index Paleont., p. 973.
PaTELLA cosTaTULA, Goldfuss. Petref., t. 177, fig. 9. —

P.. Testé turbinatd; ambitu orbiculari ; verticé elato, subacuto, erecto; costis radiantibus
majoribus (16) acutis, minoribus intermediis; costis posterioribus maximis ; margine
dentatad; bast in medio convexiusculd, ad peripheriam subconvead; peripheria integra aut
subsinuata. |

Shell turbinated, suborbicular, summit elevated, erect, and rather acute; ribs radiating,
the larger series (16 in number) are acute, with smaller ones between them; the posterior
ribs are the largest and most distant; the margin is toothed, the base is convex in its
middle part, and slightly convex at the periphery; the periphery is entire, and slightly
sinuated. |

Four of the posterior ribs occupy one third of the circumference; they are more elevated
and distant than the others. The specimens of this species in the Great Oolite never
occur of so large a size as those of P. /evis; the usual basal diameter being about
3 lines, and very rarely exceeding 4 lines, Pvleolus plicatus is scattered, indifferently,
over the shelly beds, but in fewer numbers than the other species; the shell being. very
thick and strong, is usually entire and uncompressed; both — are always found in
the upright position.

Locality. Mimchinhampton Common ; Ancliff, Wiltshire ; laters, France.

PitzoLus Lavis, G. B. Sow. Plate IX, figs. 37, 37a, 6.

PiLeoLvs Lavis, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 5—8.
— — Sow. Min. Con., t. 432, figs. 6—8.
— Brown. Illust. Foss. Conch., p. 92, t. 44, figs. 16, 17.
_ — JD Orb. 1850. Prod. Paléont., p. 299.
— — Bronn. 1848. Index Paleont., p. 973.
? PATELLA MAMILLARIS, Goldfuss. Petref., t. 177, fig. 10.
?— papyracEa, Bronn. Lethea Geogn., pl. 27, figs. 7, a, 6.

P. Testi parva, conico-depressd, levi, aut sulcis raris, obsoletis notata; basi in medio
conveatusculd.
~ Shell small, conical, but much depressed ; sometimes discoidal, smooth, or with a few
faintly-marked longitudinal irregular sulcations ; base rather convex in the middle part.

GASTEROPODA. 61

Specimens, as small as the head of a pin, are scattered over the blocks of white stone
at Bussage, and planking at Minchinhampton Common—these are smooth. The larger
shells are more distinctly sulcated, and occasionally attain a diameter of three eighths of
an inch.

Locality. It occurs in all the shelly beds at Minchinhampton; at Ancliff, in Wiltshire ;
and at Charter House, Hinton, Somersetshire. Langrune, France.

Family—TuRBINIDE.

Trocuus, Linneus, 1758.

Shell turbinated, conical; spire elevated, consisting of numerous whorls; under surface
discoidal ; aperture more or less depressed obliquely, entire, generally angular; columella
curved, more or less prominent at its union with the outer lip, contiguous to the axis of
the shell.

The fossil species of the Great Oolite are all very small, and are tolerably numerous in
the shelly beds.

Trocuus Dunxeri. Plate X, figs. 3, 3a.

T. Testa conicd, glabra; anfractibus levigatis et planis (4—6); apice acuto; aperturé
obliqua, umbilico nullo.

Shell conical, smooth; whorls very smooth and flattened ; apex acute; aperture oblique;
no umbilicus.

The extreme flatness of the whorls, and moderate elevation of the spire, are the chief
features; the good specimens have oblique lines of growth upon the last whorl, near to
the aperture.

Locality. his little species is tolerably abundant in the white stone of Eastcombs
and Bussage.

Named after Dr. W. Dunker, Professor at the Polytechnic School of Cassel.

This species has some affinity with the Zrochus glaber, Koch (Goldy. Pet. t. 1796.12);
but the volutions are striated and the base more convex.

Trocuts pLicatus, Archiac. Plate X, figs. 8, 8a.

TRocHUs PLIcATUS, Archiac. 1843. Mem. Soc. Geol. France, vol. v, p. 379, t. 29, fig. 5.
— _ D’ Orb. 1850. Prod. Paléont., p. 300.
— _ Bronn. 1848. Index Palzont., p. 1304,
9

62 MOLLUSCA FROM THE GREAT OOLITE.

T. Testé turbinatd; spird elata; anfractibus (5) subconvexis, longitudinaliter costatis ;
costis 12 rectis elatis; basi levi; apertura parvd, depressd.

Shell turbmated; spire elevated; whorls (5) rather convex, longitudinally costated ;
coste straight, elevated, smooth, about 12 in a volution; the base smooth; the aperture
small and depressed; the sutures of the whorls are strongly marked. Axis 8 lines, basal
diameter 6 lines.

Locality. The specimen figured is rather flattened; it occurred in the planking of
Minchinhampton Common, and is more acutely conical than that figured by M. d’Archiac,
of which it is considered to be only a variety.

Trocuus Ippertsoni. Plate X, figs. 4, 4a.

T. Testé conicd, spird elatd, obtusd; anfractibus (5—6), levigatis et planis, aut sub-
conveais; apertura depressd, obliqua; umbilico nullo.

Shell conical; spire elevated, obtuse ; whorls (65—6) smooth and flattened, or slightly
convex ; aperture depressed, oblique; no umbilicus, columella lip thick and excavated.

This species somewhat resembles 7. Dunkerz, from which it differs in the more elevated
spire, obtuse apex, and somewhat convex form of the whorls; the base is, likewise, more
convex and narrow: in the larger specimens these distinctive characters become more
prominent, and the sutures of the whorls are strongly marked. It occurs together with
T. Dunkeri, but in smaller numbers.

Locality, Hastscombs and Bussage.

The name in compliment to Capt. L. L. B. Ibbetson, F.R.S., whose geological surveys
of the different railways have been of considerable interest to science.

TRocHuS sauaMicER. Plate X, figs. 2, 2a, 6.

T. Testé conicé; apice obtuso; anfractibus (6—8) subcompressis, suturis impressis;
anfractibus cingulis quaternis tubuloso-squamosis; cingulo inferiort minimo; basi pland et
lew; apertura depresssé; umbilico nullo.

Shell conical; apex obtuse; whorls (6) rather compressed, the sutures well marked ;
whorls with four circles of nodules or plications which are squamosely tubular or excavated
towards the aperture, the lowest circle of nodules being much the smallest; the base is flat
and smooth; the aperture depressed ; no umbilicus.

In this species the height exceeds the basal diameter. It occurs not very unfrequently
in the planking, a rock which usually adheres very closely to shells, and the plications
become entangled with the particles of stone, so as to render good specimens very rare.

Locality. Minchinhampton.

GASTEROPODA. 63

Trocuvus Bunsuri. Plate X, fig. 1, la, 14.

T. Testé conicd; apice acuto; anfractibus (5) cingulatis; cingulis acutis inequalibus,
basi levi; apertura obliqud.

Shell conical; spire acute; whorls (5) cingulated ; encircling ribs unequal, and varying
in different individuals; the base smooth; the aperture oblique.

The cost are very large, elevated, and unequal, so as to obscure the sutures of
the whorls.

Locality. It is by far the most abundant of the Great Oolite species in the vicinity of
Minchinhampton, and is common to all the shelly beds.

This species is named in compliment to E. H. Bunbury, Esq., M.P., F.G:S.

Trocnus pitnotus. Plate X, figs. 5, 5a, 54.

T. Testé turbinatd, levissimad; anfractibus (4) planis; apice obtuso; anfractu ultimo ad
basin angulato; basi convexd; aperturd parva.

Shell turbinated, very smooth; whorls (4) flattened; apex obtuse; the last whorl
encircled with a prominent rib near to the base; base convex ; aperture small.

The very obtuse spire, and nearly cylindrical form of the last volution, give to the shell
_a cap-like figure.
Locality. From the white stone of Bussage. It is rare.

Trocuus ancgus, Goldf. Plate X, figs. 7, 7a.

Trocuus ances, Goldfuss. 1842. Petref., iti, p. 55, t. 180, fig. 3.
= — Bronn. 1848. Index Palzont., p. 1296.

T. Testé turbinatd, parva, obliqué costatd, basi cingulatad; anfractibus ('5—6) tetra-
gonis cingulatis; cingulis quaternis granulatis.

Shell small, turbinated, obliquely costated, base cingulated; whorls (5—6) angular,
encircled with four rows of granules.

Locality. Of this minute shell we have only obtained two examples, from the white

stone of Bussage, and believe it to be rare.
The sutures in the specimens, figured by Goldfuss, are more distinct.

Trocuus opsotetus, Roemer. Plate XI, figs. 1, la.

TRocHUS OBSOLETUS, Roemer. 1836. Nordd. Oolith., p. 151, t. 11, fig. 4.
— = Bronn. 1848. Index Paleont., p. 1305.

64. MOLLUSCA FROM THE GREAT OOLITE.

T. Testé conicd; anfractibus tribus levibus, lateribus planis; umbilico nullo; apertura
depresso-ovatia.

Shell conical; whorls (8) smooth, the sides flattened, no umbilicus; aperture de-
pressed, ovate. |

Possibly this may be the young of 7. glaber, Dunker; the only apparent difference
between them being, that 7! odsoletus has a base wider in proportion to the height, and
that the upper margins of the whorls are somewhat tumid, causing the sides to appear
less flattened.

Locality. It is moderately common to all the shelly beds near Minchinhampton. In
the Stonesfield slate of Wagboro’ Bush (Buckman).

Turso, Linneus, 1758.

Shell thick, ventricose, turbinated, usually sculptured or tuberculated ; spire short ;
aperture usually rounded, entire, somewhat spread out anteriorly.

Turso Hamprtonensis. Plate IX, figs. 30, 30a, 6.

T. Testa parva, turbinatd; anfractibus (4) convexis, costulis (4) granulatis elatis cinctis ;
apertura orbiculatd; umbilico parvo.
Shell small, turbinated ; whorls convex (4), turreted, encircled by four ribs, which are
elevated and closely granulated ; the aperture is nearly round ; the umbilicus small.
‘ Locality. A single, good example from the planking of Minchinhampton Common is
all we have seen.

Turbo ELABORATUS. Bean, ms. Plate IX, fig. 27.

TURBO ELABORATUS, Lycett. 1850. Annals of Nat. Hist., vol. vi, p. 416, pl. 11, ag: 2.

T. Testé conoided; anfractibus (4—5), superné planatis, inferné subconveais, et costatis ;
costis magnis longitudinalibus numerosis et elatis, lineisque transversis decussatis; apertura
ovata; umbilico nullo.

Shell conoidal; whorls (4—5), their upper borders flattened or nearly horizontal,
smooth ; their lower portions slightly convex, with numerous elevated large, longitudinal
costae, decussated by numerous, closely-arranged transverse lines; aperture oval; no
umbilicus.

Locality. The planking of Minchinhampton Common and white stone of Bussage
have furnished this species, but it is rare at both localities; it has, likewise, been
obtained from the middle division of the Inferior Oolite in the same district, and occurs
also in the same formation in Normandy.

GASTEROPODA. 65

Turso SHarpet. Plate IX, figs. 28, 28z.

T. Testé conoided; anfractibus (4) convexis, gradatim tumescentibus, suturis profunde
impressis; anfractibus liners elatis equalibus, longitudinalibus et regularibus ornatis, aliis
transversis decussatis; lines transversis superne distantibus, inferné approwimatis; apertura
ovata; umbilico nullo.

Shell conoidal; whorls (4) convex, gradually increasing in size, their sutures deeply
impressed ; the surface of the whorls is ornamented with numerous equal and regular lon-
gitudinal lines, tranversely decussated by others of equal size; the transverse lines are
arranged distantly upon the upper portions of the whorls, but more nearly upon the lower ;
aperture oval ; no umbilicus.

Both descriptions of lines are scarcely discernible, except upon the last volution, where
they are prominent; but the lower portion of this whorl is destitute of the longitudinal
lines, which extend over only the upper half.

The general figure differs from Zurbo elaboratus (Plate IX, fig. 27), in the more gradual
increase of the whorls, which are likewise more convex, and have not the distinct sulcus
or area upon their upper portions, nor the large elevated coste ; these distinctive features
have been faithfully delineated by the artist. The longitudinal lines are equal in size to
those which are transverse, forming a simple cross-barred’ surface.

Locality. It is rare; but has been found both at Bussage and Minchinhampton
Common. ‘This species is dedicated to D. Sharpe, Esq., F.R.S.

Turso premaus. Plate IX, figs. 29, 29a.

T. Testéi parva, conicé; apice obtuso; anfractibus (A—5) planatis, costis longitudr-
nalibus numerosis (circa 16 in ambitu), cum punctis interstitialibus ornatis; aperturd
depressa.

Shell small, conical, apex obtuse; whorls (4—5) flattened, ornamented with numerous
longitudinal ribs (about 16 in a volution), the interstitial spaces being closely and deeply
punctated ; aperture depressed. ‘The costz are large and equal ; their continuity is inter-
rupted by a narrow, encircling band at the base of each whorl; the height of the entire
shell is somewhat greater than its transverse diameter at the base; the exact character of
the mouth not being exposed, it is placed only provisionally in the genus Zwrdo.

Locality.. Minchinhampton Common, at which place it would seem to be rare.

Turso capitaneus, Goldf. Plate IX, figs. 33, 33a.

TURBO CAPITANEUS, Goldfuss. 1842. Petref., ii, p. 97, t. 194, fig. 1.
= _ Bronn. 1848. Index Palzont., p. 1318.

66 MOLLUSCA FROM THE GREAT OOLITE.

T. Testi turbinato-conicd, acutd, lineata; basi granulatd cingulata; anfractibus (6)
subteretibus bicarinatis, carinis granulis erectis coronatis; interstitirs canaliculatis.

Shell turbinated or conical ; apex acute, the base with a granular band encircling it ;
the whorls (6) are turreted, and have two encircling carinz, the carne are elevated and
fringed with closely-arranged granules, the interstitial spaces are canaliculated.

Locality. This elegant species occurs rarely in the planking of Minchinhampton
Common ; it is usually crushed or otherwise imperfect ; it occurs likewise in the Inferior
Oolite of Gloucestershire more frequently, and is usually better preserved.

We have ventured to assign this shell to the species described by Goldfuss, although
its state of preservation does not show the longitudinal markings characteristic of that
species.

Turso optusus, Sow. Plate XI, figs. 9, 9a.

TuRBO optusus, Sow. 1827. Min. Con., t. 551, fig. 2.
— — Brown. 1849. Illust. Foss. Conch., p. 73, t. 38, figs. 41, 42.
TurBo suBoBtusus, D’Orb. 1850. Prod. Paléont., p. 300.

T. Testé parva, conicd; spirdé obtusa; anfractibus (4) planatis, ultimo superné sub-
concavo, inferne convexo, striis .crebris, subundatis, transversis cincto; apertura ovaté;
umbilico nullo.

Shell small, conical; spire obtuse; whorls 4, their sides flattened, the last whorl
slightly concave in the upper and convex in its lower part; the whorls are encircled with
strie, closely arranged and slightly undulated ; aperture ovate; no umbilicus.

In this minute species, the junctions of the whorls are strongly marked ; the striz are
shghtly punctated, giving to the spaces between them a rough or scabrous aspect; the
striz, however, are but faintly impressed, and are scarcely visible upon some specimens ;
the substance of the shell is thick, its axial slightly exceeding its transverse diameter, or
beimg equal to about 2 lines.

Locality. Minchinhampton Common and Bussage. At both places it is somewhat
rare, but occurs in more than one shelly bed. Ancliff, Wiltshire.

Turso Gomonpzl. Plate XI, fig. 5.

T. Testé conoided, spird elatd, acutd; anfractibus (5) planatis et costatis; costis trans-
versis (4) densé nodulosis; apertura ovata, subdepressd, umbilico nullo.

Shell conoidal, spire elevated, acute; whorls (5) flattened and costated; the coste
(4 in number) are transversal, and densely nodulated ; the aperture is ovate and somewhat
depressed ; and there is no umbilicus.

The length of the aperture is scarcely equal to half the entire length of the shell, and

GASTEROPODA. 67

somewhat exceeds its transverse diameter ; it is moderately large, and wide at the base;
the junctions of the whorls are strongly marked; the encircling costz are large, closely
arranged, and very densely nodulated. Axis 8 lines, transverse diameter of the last
volution 6 lines.

Locality. Minchihampton Common, where it occurs in the coarse planking: it is
moderately rare.

We have dedicated this species to H. Gomonde, Esq., of Cheltenham, who has kindly
allowed us the use of his collection of oolitic fossils.

Monoponta, Lamarck. 1801.

Shell turbinated, aperture entire, base of the columella forming a tooth, with an
exposed umbilicus half surrounding it; beneath the tooth is a longitudinal groove, the
edges of which are acute; the outer lip is thick, striated within.

Monoponta Lyrnnin, Archiac. Plate XI, figs. 4, 4a, 5.

Monoponta Lyr ui, Archiac. 1843. Mem. Geol. Soc. France, tom. v, t. 29, fig. 8.
_ — Bronn. 1848. Index Paleont., p. 742.
Turso Lyriiu, D’Orb. 1850. Prod. Paléont., p. 301.

M. Testa turbinata, spird acuté, anfractibus (4) convexis, tricinctis; cingillis elatis et
nodulosis; nodulis approximatis, antrorsum concavis; anfractu ultimo ventricoso, cingillis
7 ornato, ultimo cingillo maximo et profunde crenulato; umbilico magno.

Shell turbimated ; spire elevated, acute ; whorls (4) convex, encircled with three carine ;
carinee elevated and nodular ; nodules placed close together, and concave on their anterior
sides; the last whorl ventricose; encircling bands 7, the last being the largest and is
deeply crenulated ; the umbilicus is large.

The markings vary considerably in this species. In some specimens the encircling
costee are nearly smooth, in others they are merely notched; but the greater number are
distinctly nodulated ; the junctions of the whorls are deeply impressed; and the entire
shell is very thick.

Locality. ‘This shell is abundant in the shelly beds near Minchinhampton ; the size
varies from a diameter of 1 line to 5 lines. In the Great Oolite, Eparcy (Aisne), France.

Monoponra imBricata. Plate XI, figs. 3, 3a.

M. Testé parva, conicd; spird acuminata; anfractibus subplanis; striis imbricatis,
transversis (4) cinctis; anfractu ultimo ad basin subangulato.

68 MOLLUSCA FROM THE GREAT OOLITE.

Shell small, conical; spire acuminated; whorls rather flattened, and encircled with
four imbricated striz ; the last whorl is somewhat angulated towards its base.

The imbricated strize are fine and closely arranged, those beneath the angle upon the
last whorl are larger; the aperture is semilunar and contracted. As compared with
M. decussata, this shell is more lengthened, the apex pointed, and the encircling stric

much fewer.
Locality. It is rare, and occurs, with the species before mentioned, at Minchinhampton.

Monoponta Formosa. Plate XI, figs. 6, 6a, 6.

M. Testé turbinatd, spird subdepressé, prominuld, obtusd; anfractu ultimo in medio
carinato, striis transversis crebris tenuissimis cincto; carind levigatd, rotundatd, obtusa,
striis supra carinam positis magis elatis; apertura semilunart subcontractd.

Shell turbinated, spire rather depressed, small, obtuse ; the last whorl carinated in its
middle part; the carina smooth, rounded, and obtuse; the last whorl has likewise trans-
verse, closely arranged, fine, and crenulated striz, those above the mesial carina being
larger than the others; aperture semilunar, somewhat contracted.

In the greater number of specimens, more especially those of large dimensions, the
encircling striz are obsolete, the only markings being the lines of growth. Diameter of
largest specimens, 45 lines.

7 Locality. tis abundant and common to all the shelly beds near Minchinhampton.

Monoponta pecussaTaA. Plate XI, figs. 9, 9a.

M. Testé parva, conicd; apice obtuso; anfractibus planis, suturis impressis; striis
erebris transversis et longitudinalibus decussatis.

Shell small, conical; apex obtuse; whorls flattened, their sutures impressed, encircled
with numerous transverse strize, decussated and impressed by others longitudinally.

This shell is more obtuse than J. imbricata; the last whorl is more cylindrical than
the others ; the lines upon its surface are so delicate as to be scarcely visible, unless under
a magnifier.

Locality. It is rare, and occurs with M. imbricata; in the soft shelly Oolite of
Minchinhampton Common.

Monoponta Lazapyet, Archiac, sp. Plate XI, fig. 2; var. fig. 11, lla.

Trocuus LapapyeEl, Archiac. 1843. Mém. Soc. Géol. de France, iii, p. 379, t. 29,
figs. 2, 2a.
TURBO = D’ Orb, 1850. Prod. Paléont., p. 301.
? Monoponta La&viGATA, Goldfuss. Petref., p. 101, t. 195, fig. 5.
? Wurzo Destonccuampsi, Desh. Elem. de Conchyl., t. 68, figs. 17, 18.

GASTEROPODA. 69

M. Testa turbinato-conicd, levi; spird elatd, obtusd; anfractibus planis seu subconvexis ;
suturis vie impressis; anfrdactu ultimo permagno; aperturd ovatd; umbilico nullo. ditate
adulta testa elatiore.

Shell turbinated, conical, oblique, smooth ; spire elevated, obtuse ; whorls flattened, or
slightly convex, the sutures rather mdistinct ; the last whorl very large; the aperture ovate,
and the base without umbilicus or sulcus.

The young shells are rather discoidal, but with increase of growth gradually become
obliquely conical, so much so, that the two extremes of the figure would scarcely be taken
for the same species.

Locality. tis abundant in all the shelly beds of the Great Oolite formation near
Minchinhampton. LEparcy, France.

Sonarium, Zam. 1801.

OmaLaxis. Brirrontia, Deshayes.

Shell depressed, conical, or discoidal; base concave, or widely umbilicated, the spiral
margin of which is angulated and crenulated ; aperture trapezoidal, with a thin peritreme.

SoLaRiuM PoLyGoniIuM, Archiac. Plate IX, figs. 24, 24a, 0b.

SoLARIUM POLYGONIUM, Archiac. 1843. Mém. Soc. Geol. de France, tom. v, p. 378,
pl. 29, fig. 1.
—_ _— Bronn. 1848. Index Palzont., p. 1152.
— — D'Orb. 1850. Prod. Paléont., p. 300.

S. Testéd discoided, spird parva, anfractibus (4) planis, ultimo carinato; angulis (9)
costatis ; costis elatioribus ; liners transversis et longitudinalibus decussatis ; carind parva,
nodulosd prope suturam sitd.

Shell discoidal, spire small, whorls (4) flattened, the last whorl carmated and angulated ;
angles (9) costated ; costa elevated; there are also encircling lines decussated by others
which are longitudinal, and a small, closely nodulated carina, surrounding the upper portion
of the whorls, near to the suture; the first two volutions are smooth, rounded, elevated,
but minute.

Locality. This species occurs in the vicinity of Minchinhampton more frequently than
any other of the genus, but, owing to its thinness and delicacy, few examples are well
preserved. The white stone of Bussage is the most favorable position for obtaining it.

Great Oolite, Eparcy, France (D’ Archiac).

SoLARIUM vARIcosuM. Plate IX, figs. 23, 23a, 4.

S. Testa conico-depressé ; anfractibus (4) angulatis, lineis crebris transversis et longi-
10

70 MOLLUSCA FROM THE GREAT OOLITE.

tudinalibus decussantibus et varicibus trregularibus angulatis, ornatis ; umbilico contracto,
basi lata, tenuissimé cancellato.

Shell conical, depressed; whorls (4) angulated, and encircled with closely-arranged
lines, longitudinally crossed by others, and equally densely arranged; varices elevated,
longitudinal, angulated in their middle part, and placed at irregular distances; the um-
bilicus is contracted ; the base is wide, slightly convex, and has a finely-cancellated surface.

Locality. It occurs in the planking of Minchinhampton Common, very rarely.

SoLaRium DiscuLum. Plate IX, figs. 25, 25a, 6.

S. Testé parva, superné discoided, inferné concavd, lateribus angustatis, planis ; spird
viv elaté; anfractibus 3, marginibus angulatis et nodulosis, nodulis crebris, depressis +
umbilico magno, margine noduloso.

Shell small, discoidal above, concave beneath, the sides narrow and flattened ; the spire,
scarcely elevated, consists of 3 whorls, their margins angulated and nodulated, the nodules
closely arranged and depressed ; the umbilicus is large and deep, its margin is nodulated ;
the flattened sides of the last whorl are finely striated transversely.

The extreme flatness of the upper surface, the generally depressed form, and angular
outer margin, distinguish it from contemporaneous species.

Locality. tis rare, and occurs in the planking at Minchinhampton, and in the white
stone of Bussage and Eastcombs.

DELPHINULA, Lam.

Shell turbinated, thick, rugose; whorls few, convex or angular; aperture orbicular,
entire ; peritreme continuous, thickened ; umbilicus conspicuous and denticulated.

DELPHINULA CoRONATA, Sow. sp. Plate IX, fig. 26.

EvompPHaLus Coronatus, Sow. 1824. Min. Con., t. 450, fig. 3.
— — Brown. Illust. Foss. Conch., p. 82, t. 43, figs. 20—22.
DELPHINULA CoRONATA, Flem, 1827, Brit. Anim., p. 312.
— — Bronn. 1848, Index Palzeont., p. 406.
? DELPHINULA STELLATA, Buvignier. Mém. Soc. Philom. Verdun, 2. pl. 5. figs. 35, 36.
SoLaRrtum coronatuM, D’Orb. Prod. Paléont., p. 300.

D, Testé discoided, parvd, superné pland, angulatd et spinigerd ; spinis latis, acutis et
prominentibus ; basi concavd.

Shell discoidal above, flattened, angular, and spined; spines broad, pointed, placed at
the angle of the last volution ; base concave.

GASTEROPODA. 71

Locality. This little species is very rare. It occurs in the planking of Minchinhampton
Common.

The specimen figured in the ‘ Min. Con.’ is from the Oolite of Ancliff, Wiltshire ;
M. Buvignier describes his species as occurring in the Coral Rag of St. Mihiel, France.

DELPHINTLA Buckmanni. Plate V, fig. 8.

D. Testé turbinatd, spiré elata, anfractibus (3—4) costatis ; ultimo anfractu ventricoso,
subquadrato, in medio costato ; costis longitudinalibus, numerosis, rectis, et rotundatis, superneé
acutis, striis transversis impressis ; umbilico contracto, striis tenuissimis cincto.

Shell turbinated, spire elevated, whorls (83—4) costated, the last whorl ventricose,
subquadrate, costated in its middle portion ; the coste are longitudinal, numerous, perpen-
dicular, acute at their upper extremities, and impressed with transverse striz ; the umbilicus
is contracted, and encircled with very fine striz.

The costa are scarcely visible upon the upper surface of the last whorl, and nearly
disappear towards its base ; the aperture is suborbicular, the lips being less incrassated than
is sometimes seen in this genus. Individual specimens vary very much in the elevation of
the spire, and in the degree of squareness or angularity which the last whorl acquires; in
some the umbilicus is scarcely visible, which usually happens in the more elevated shells.

Locality. This shell occurs in the beds of coarse planking on Minchinhampton
Common ; but well-preserved examples are rare.

DELPHINULA ALTA. Plate IX, fig. 31.

D. Testé turbinaté; spird elatd, obtusd; anfractibus angulatis (interné rotundatis) ;
anfractu ultimo tuberculis acutis, crebris sed distinctis ornato ; basi quadricinctd, costulis
tuberculatis ; umbilico magno profundo ; apertura subquadratda.

Shell turbinated ; spire elevated, obtuse; whorls angular (the moulds of the interior
being convex) ; the last whorl has, surrounding its upper part, a circle of elevated, acute,
distinct, and closely-arranged tubercles; the base is encircled with four elevated ribs,
which are closely tuberculated ; the upper or flatter part of the last whorl has several fine
encircling lines (often indistinct) ; the umbilicus is large and deep, the aperture subquadrate
and rather small.

Locality. Minchinhampton. This pretty shell occurs in the planking, and is not
uncommon ; but the coarseness of the deposit is unfavorable to the preservation of its
more delicate features. Our best specimens may therefore be regarded as some of the
choicer productions of the formation.

72 MOLLUSCA FROM THE GREAT OOLITE.

Sub-genus, CROSSOSTOMA.

C. Testd crassd, turbinatd, levi, subdepressé; anfractibus subplanis, paucis; apice
obtuso; apertura subrotundd, integra; columelléd dentem obtusam formante; labio externo
levi, umbilico nullo. In etate senict aperturé contractd crassa, orbiculari, laminé
testaced flabelliformi cincta.

Shell thick, turbinated, smooth, somewhat depressed or Rotelliform ; whorls more or
less flattened, few; apex of the spire obtuse, depressed; aperture nearly circular, entire ;
the columella forms at its base a simple prominent obtuse tooth ; the outer lip is smooth ;
there is no umbilicus. In the oldest state of growth, the aperture becomes contracted
by the deposition of shelly matter; it is perfectly orbicular, the circumference very
thick, and is encircled with a thin frilled appendage, always irregular, and more or less
produced.

In this genus the aperture undergoes a remarkable change as it approaches the last
state of growth. The surface is very smooth, the figure Rotelliform, and the aperture is
that of a smooth depressed A/onodonta ; and this is the usual condition in which the several
species occur. Finally, however, a few thick lines of growth closely follow each other ; the
columella is concealed by a deposition of shelly matter; the aperture becomes precisely
that of a Delphinula, and is surrounded by an additional shelly irregular lamina, which
projects from it in every direction."

Crossostoma Prarti. Plate XI, figs. 21, 21a.

C. Testa parva discoided levi; spird subpland, vie elatd; lineis incrementi rugis prope
aperturam sitis; aperturd parva, orbiculatd, labris incrassatis, lamind testaced abnorme
cincto.

Shell small, discoidal; spire nearly flat, or but slightly elevated; the last volution has
some rugose lines of growth situated near to the aperture; aperture small, orbicular ; the
lips incrassated, and encircled with an irregular shelly lamina.

The shelly encircling lamina is produced by an irregular expansion of the ultimate fold
of growth; the few rugose plicee have the more remarkable aspect, as the whole of the
shell, excepting within the brief space of two lines from the aperture, is perfectly smooth.

Locality. Inferior Oolite near Bath.

We are indebted to S. P. Pratt, Hsq., F.R.S., for the original specimens obtained from
that locality.

1M. A. D’Orbigny has described a species belonging to this sub-genus, under the name Delphinula
reflexilabrum, from the Lias of Fontaine-Etoupefour: ‘ Shell smooth, resembling a Turbo, but having a
reflected, sharp, lamellar peristome surrounding the mouth.”—Prod. Paléont., p. 229.

GASTEROPODA. 73

CrossosToMA? piscoripEuM. Plate XI, figs. 7, 7a, 74.

C. Testé levi, depressé; spirdé prominuld; anfractibus angustatis, suturis impressis;
apertura parva, suborbiculari.

Shell smooth, depressed ; spire but little elevated, or nearly flat; whorls narrow, the
sutures distinct ; aperture small, basal nearly round. The height is equal to half the basal

diameter.
This is, probably, only a variety of C. Pratt, and in a state in which all our Great

Oolite specimens occur—the outer lip not being quite entire, and extremely thin and
slightly rugged, never perfecting a well-defined lip (C. discoideum); the change to the
ultimate condition occupies a space which does not exceed one fourth of a volution, a
few rugged lines of growth are formed; an irregular lamina next protrudes, forming a kind
of frill around a contracted, thickened, and orbicular aperture, as in C. Pratti?.

Locality. Minchinhampton Common and Bussage, at which places it occurs somewhat
rarely, and in more than one of the shelly beds.

CrossosToMA? HELIcIFoRME. Plate XI, fig. 8.

C. Testé levi, turbinatd, subdepressd; spird parvad prominuld; anfractibus convexi-
usculis; apertura elliptica.

Shell. smooth, turbinated, somewhat depressed ; spire small, but little elevated ; whorls
rather convex ; aperture elliptical.

Locality. Yt is somewhat rare; our specimens have been obtained from the planking
of Minchinhampton Common ; it is likewise found in the middle division of the Inferior
Oolite at Leckhampton, near Cheltenham.

This species has the general form of C. discoideum, but the spire is more elevated ;
they are only provisionally referred to Crossostoma, having somewhat the aspect of Mono-
donta, and even (in C. discoideum), the thickened base of Rofe//a.

PHASIANELLA, Lam. 1812.

Shell oval, smooth; aperture oval, entire, forming an acute angle posteriorly at the
junction of the columella and outer lip; outer lip thin; imner lip spread over a portion of
the columella.

The Great Oolite shells provisionally referred to this genus are small, and like their
recent congeners, individuals of the same species offer a considerable variety of form, which
makes their determination rather difficult.

74 MOLLUSCA FROM THE GREAT OOLITE.

PHASIANELLA ELEGANS. Plate XI, figs. 27, 27a.

P. Testa ovato-elongatd; anfractibus (7) convexiusculis; spird acutd, apertura longiore.

Shell ovately elongated, whorls (7) convex, the spire acute, larger than the aperture.

The height of the last volution is rather more than the remainder of the spire; the
whorls are narrow and convex; the sutures strongly impressed. Axis 16 lines, transverse
diameter 8 lines.

Locality. The planking of Minchinhampton Common has supplied this species in
considerable numbers.

PHASIANELLA LeYMERIEI, Archiac. Plate XI, figs. 31, 31a, 32.

PHASIANELLA LEYMERIEI, Archiac. 1843. Mém. Soc. Géol. Fr., tom. v, t. 28, fig. 12.
— — D’ Orb. 1850. Prod. Paléont., p. 301.
— — Bronn. Index Palzont., p. 956.

P. Testa ovata, sub-globosa; spird parva; anfractibus (6) angustis, convexiusculis, anfractu
ultimo amplo; apertura obliqud magna.

Shell ovate, subglobose ; spire small ; whorls (6) narrow, convex ; the last whorl large ;
aperture oblique and large.

The length of the aperture is greater than that of the remainder of the spire, and the
length of the last volution is twice as great as the spire. The variety of figure in this
species is more than usually considerable. Axis 12 lines, transverse diameter 8 lines.

Locality. Vt is the most common of the Great Oolite Phasianelle, and occurs in
all the shelly beds near Minchinhampton.

PHASIANELLA conica. Plate XI, figs. 30, 30a.

P. Testé ovato-conicd, acuté; spird mediocriter elatd, conicd; anfractibus (6) planis,
ultimo elongato; apertura obliqud angustda.

Shell ovately conical, acute; spire moderately elevated, conical; whorls (6) flattened ;
the last whorl elongated ; aperture oblique and narrow.

This species is somewhat spindle-shaped, narrowing at both ends; the length of the
aperture is less than that of the spire; but the last two volutions occupy more than two
thirds of the entire length of the shell. Axis 10 lines, transverse diameter 4 lines.

Locality. tis not uncommon, and occurs in all the shelly beds, more especially at
Minchinhampton Common.

GASTEROPODA. 75

PHASIANELLA AcUTIUSCULA. Plate XI, figs. 28, 28a.

P. Testé ovato-conicd; spird elatd, acuté; anfractibus planis, angustis; anfractu ultimo
ovato, magnitudine modico.

Shell ovately conical; spire elevated, acute; whorls flattened, narrow; the last whorl
ovate, its size moderate.

The figure most nearly approaches to P. conica, but it is less gibbose; the spire is
more acute, elevated; the whorls less numerous and narrow.

Locality. It is not uncommon, and is found in all the shelly beds near to Minchin-
hampton.

PHASIANELLA NUcIFoRMIS. Plate XI, fig. 26.

P. Testé ovato-elongataé; spird parva; anfractibus (6) subpianis, ultimo elongato;
apertura angustata.

Shell ovately elongated ; spire small; whorls (6) flattened, the last elongated ; aperture
narrow.

The length of the aperture is equal to that of the spire; the spire is acute; the volutions
very narrow, except the last two turns, which are much elongated. Axis 9 lines, transverse
diameter 5 lines.

Locality. \t occurs in the planking of Minchinhampton Common, but is rare.

PHASIANELLA PARVULA. Plate XI, figs. 29, 29a.

P. Testé parva; spiraé elaté, apice acuto; anfractibus (6—7) planis aut subconvewvis,
angustis; anfractu ultimo subgloboso; apertura obliqud; columella arcuatd.

Shell small; spire elevated; apex acute; whorls (6—7) flattened, or rather slightly
convex and narrow; the last whorl globose and large; the aperture oblique and oval; the
columella curved at its base.

The length of the aperture is two fifths of the entire shell; the whorls are more numerous,
and the apex more acute, than is found in the other Great Oolite species; the aperture is
rather small and contracted at its base. Axis 5 lines, transverse diameter 24 lines. Rare.

Locality. Minchinhampton Common.

76 MOLLUSCA FROM THE GREAT OOLITE.

PHASIANELLA TuMIDULA. Plate XI, figs. 25, 25a.

P. Testé turbinatd, elongata; spird acuta; anfractibus convewis (8), suturis depressis ;
anfractu ultimo globoso; aperturd magna ovato-rotundata.

Shell turbinated, elongated; spire acute; whorls (8) convex, the sutures deeply
depressed ; the last whorl globose ; the aperture large, ovately rounded.

This species has an elevated, acute spire, and convex whorls, and is remarkable for the
sudden increase of the last two volutions, which are very ventricose. Neither of our
specimens are quite perfect about the outer lip; but the distinctive character of the species
is sufficiently evident. Axis 19 lines, transverse diameter 11 lines.

Locality. It occurs rarely in the planking at Minchmhampton Common.

Family—PLEUROTOMARIDE.

PievrotomaRtia, Defrance. 1825.

ScrssurELLA, D’Orbigny. 1823.

Shell turbinated or conical; aperture subquadrate, the angles rounded ; outer lip thin
and sharp, having a fissure or deep notch in the middle part, or near to the suture; an
encircling band or rib round each whorl follows the fissure.

The Plewrotomari@ are rare in the Minchinhampton beds, and the larger specimens are
usually broken. It will be observed, in the following descriptions, how very few examples
of each species have been obtained, so that we are almost enabled to give their number
with exactness. Placed amidst such a multitude and variety of molluscous relics, in spots
teeming with life, it is not easy to account for their rarity and imperfect condition.
Inferring that they were usually gregareous, we are led to suspect that the /ittoral condition
of these shelly beds was not suited to their propagation, and that the larger imperfect
specimens were denizens of greater depths, the shells occasionally being stranded among
the more littoral Mollusks. As a remarkable instance of the recurrence of similar phe-
nomena at a very distant locality, we would direct attention to the elaborate and valuable
Memoir of M. Deslongchamps,' on the Plewrotomarie of the secondary formations of
Calvados, in which 53 species are mentioned as occurring in the Lias and the Lower and
Middle Oolitic systems. It is stated that they are exceedingly abundant ; but, on referring
to the Great Oolite species, 11 in number, we find, with one exception only, a repetition
of the following remarks appended to them: ‘One example; two examples; rare; very
rare.” In fact, when describing the species which we have identified in that Memoir, we
seem, when stating their numbers, to be repeating the words of its author.

1 Mém. Soc. Linn. de Normandie, vol. viii.

GASTEROPODA. 1%

PLEUROTOMARIA SCALARIS, Des/. Plate X, fig. 14.

PLEUROTOMARIA SCALARIS, Deslongchamps. 1848. Mém. Soc. Linn. de Normandie,
vol. vii, p. 67, pl. 8, fig. 1.
Var. a, TURGIDULA, Desl., ibid., p. 67.
a SCALARIS, D’Orb. 1850. Prod. Paléont., p. 269.

P. Testa crassa, trochiformi; spird plus minusve exsertd; apice acuto; anfractibus cari-
natis, subgradatis aut gradatis, tranversé striatis, sinu magno profundo; fascid sinis
prominente, lavi aut longitrorsum densissime striatd, in medio anfractuum sitd; ultimo
anfractu ad basim angulato, obtusiusculo; basi plané aut subconverd; umbilico aut
parvo, aut minimo, aut nullo; aperturé subquadratd, labro sinistro crassiori reflexo.
(Deslongchamps.)

Shell thick, trochiform; spire more or less elevated; apex acute; whorls carinated,
more or less step-like, transversely striated; sinus large and deep; band of the sinus
prominent, smooth, or very finely striated longitudinally, and placed in the middle of the
whorl; the last whorl is angulated, or somewhat obtuse at the lower margin; the base
is flat, or slightly convex ; the umbilicus small, very minute, or wanting altogether; the
aperture subquadrate, the left lip being thick and turned outwards.

Altogether we have obtained eight or nine specimens. ‘They vary in the elevation of
the spire, and agree with the first variety of P. scalaris of M. Deslongchamps, viz. the
turgidula which he thus characterises :

“Testa conicd, anfractibus subrotundato angulatis, vie gradatis, transversim obsoletissime
striatis, striis in ultimo basis vicinis; basi subconverd, striis radiatis incrementi tantum
notatd, umbilico minimo.”

Axis 29 lines, basal diameter 26 lines.

Locality. The planking of Minchinhampton Common has furnished all our specimens,
only three of which are well preserved. Inferior Oolite, Bayeux. (Des/.)

Pievrotomaria Pacopus. Plate X, fig. 9. Var. DepaupErata.

? PLEUROTOMARIA PAGODUS, Deslongchamps. 1848. Mém. Soc. Linn. de Normandie.
vol. viii, pl. 14, fig. 4.
== — D’ Orb. 1850. Prod. Paléont., p. 301.

P. Testi trochiformi, subturritd; apice acutiori; anfractibus gradatis, infra fasciam
constrictis, transversim et tenuissime striatis, in medio nodis coronatis ad suturam subundu-
latis; sinu magno, profundo; fascid sintis pland, densissime longitrorsim striata, infra

11]

78 MOLLUSCA FROM THE GREAT OOLITE.

nodos sité; ultimo anfractu ad basim angulato subnodoso; basi subconcavd, concentrice
striata, striis tenuibus, profundis ad umbilicum minimum nullis; apertura subpentagond.

Shell trochiform, subturreted ; apex rather acute; whorls step-like, narrowed beneath
the band, transversely and finely striated, coronated in the middle by a circle of nodules,
subundulated even to the suture; the sinus is large and deep, the band of the sinus is flat,
densely striated longitudinally, and situated beneath the nodules; the last whorl is
angulated at lower margin and slightly nodulated; the base is somewhat concave, con-
centrically and very delicately striated; the umbilicus is very small or obsolete; the aperture
is nearly pentagonal.

Locality. Two specimens only have been found in the Minchinhampton district. Both
are small compared with the fine specimen figured by M. Deslongchamps, who is very
fortunate in that respect, considering that the species is likewise very rare in Normandy.
Its position is the soft shelly Oolite beneath the planking at Minchinhampton Common.

PLEUROTOMARIA DIscoIDEA. Plate X, fig. 12.

P. Testé turbinato-depressd, spird obtusa, anfractibus subconveais, levibus et angustatis ;
sinu angustissimo ; fascia sinus stricta, et planatd interdum vie notatd, infrd mediam an-
Jractuum sitd ; ultimo anfractu ad basim angulato convexo, basi subconvead, levi ; umbilico
minuto aut nullo, apertura subquadratd.

Shell turbinated, depressed: spire obtuse; whorls somewhat convex, smooth, and
narrow ; sinus very narrow; the band of the sinus narrow, flattened, and smooth, some-
times scarcely distinguishable, and placed beneath the middle of the whorls; the last whorl
is angulated, and convex at the margin; the base is slightly convex, and smooth; the
umbilicus minute or wanting; the aperture subquadrate.

The small elevation of the spire, which is only equal to two fifths of the basal diameter,
necessarily renders the whorls narrow ; the basal angle of the last whorl is unusually acute ;
the sutures of the whorls are strongly marked.

Though possessing few distinctive characters, it is little liable to be confounded with
others ; the extreme smoothness, depressed form, and proximity of the sinus and fascia to
the base of the whorls, are obvious and sufficient features. Height 4 lines, basal diameter
10 lines.

Locality. We can enumerate seven specimens; they occurred in the white stone at
Bussage ; also in the lower portion of the formation on the south side of Minchinhampton
Common, where the rock is not very shelly.

GASTEROPODA. 79

PievRoToMARIA oBESA, Des/. Plate X, fig. 11.

PLEUROTOMARIA OBEsA, Deslongchamps. 1848. Mém. Soc. Linn. de Normandie.
vol. viii, p. 134, pl. 14, fig. 1.
-— _ D’Orb. 1850. Prod. Paléont., p. 302.

P. Testé trochiformi, apice subacuto, anfractibus rotundatis, in medio subdepressis,
transversé striatis ; striis frequentibus obsoletis, equalibus, sinu angustissimo, profundissimo,
fascia sinis strictissimd, vie a striis distinctd, longitrorsum tamen densissimé striata, in medio
anfractuum sitd, ultimo anfractu ad basim angulato-convexo ; basi subconvead concentricé
striata, striis rarioribus obsoletissimis, hinc et indé evanescentibus, umbilico magno, pervio
(parietibus subplanis), ad marginem sulcato, sulco sat parvo, spiraliter ascendente, suture
interne vicino, sed ab ea distinctissimo; aperturd subquadratd. (Deslongchamps.)

Shell trochiform, apex subacute ; whorls somewhat convex, slightly depressed in their
middle, and transversely striated; the striae, which are equal, are frequently obsolete ; the
sinus is narrow and deep, the band very narrow, so as scarcely to be distinguished from
the strize ; but it is densely striated longitudinally, and situated in the middle of the whorls ;
the last whorl is convexly angulated at the lower margin; the base is somewhat convex,
concentrically striated, the striz beimg frequently scarcely distinguishable ; the umbilicus
is large, pervious (the sides nearly flat), suleated at its margin, and ascends the interior
spirally, near to the internal sutures, but distinct from them; the aperture is subquadrate.

Locality. We have only procured two specimens, which do not fully exhibit the
minute features of this species, so carefully described by M. Deslongchamps. Both were
obtained from the planking of Minchinhampton Common. Great Oolite, Ranville.
(Des!.)

PLEUROTOMARIA CLATHRATA, Goldf. Plate X, figs. 6, 6a.

? PLEUROTOMARIA CLATHRATA, Goldfuss. 1843. Petref, p. 74, t. 186, fig. 8.
-- _ D’ Orb. 1850. Prod. Paleont., p. 356.

P. Testa trochiform subdepressd, apice acuto, anfractibus planis, (5,) cingillis lineisque
cerebris clathratis ; basi convexo-pland tenuissimé clathrata ; umbilico minimo aut nullo;
anfractibus superné obsolete tuberculatis ; fascid siniis marginal.

Shell trochiform, somewhat depressed ; apex acute ; whorls (5) flattened, their sutures
well marked ; covered with very fine, regular, equal lines, both longitudinal and transverse ;
the base is flattened or slightly convex, with a very fine cancellated surface; umbilicus

80 MOLLUSCA FROM THE GREAT OOLITE.

minute or obsolete; the upper border of the whorls has an obscure encircling row of
tubercles ; fascia of the sinus marginal; the aperture quadrate.

The delicate markings upon the surface are only visible under a magnifier. The general
figure and character of the surface nearly approximates to Plewrotomaria punctulata,
Deslongchamps, but in that species the fascia of the sinus is placed upon the middle of the
whorls, and it is destitute of the upper encircling band of tubercles.

Axis 4 lines, basal diameter 6 lines. .

Locality. The white stone of Bussage has furnished our specimen, but the species is

very rare.

PLEUROTOMARIA cComposITa. Plate X, figs. 13, 13a.

P. Testé turbinatd, conicd; spird subacutd ; anfractibus superne conveais, infra
planatis vel subconcavis ; sinu magno; fascid sinus latd, longitudinaliter striata, in medio
anfractuum sitd ; anfractibus supra fasciam densissimé longitudinaliter et oblique striatis ;
strvis tnequalibus; infra fasciam striis transversis equalibus profundis subdistantibus ;
anfractu ultimo ad basim rotundato; facie infimd pland, vel subconvexd, longitudinaliter
tenuissime et inequaliter undulatim striata; umbilico nullo? vel minima; aperturd sub-
pentagonal.

Shell turreted, conical; spire subacute; whorls convex in their upper portions,
flattened or slightly concave in their lower; the sinus large, the band of the sinus wide,
longitudinally striated, and situated in the middle of the whorls; the whorls above the
band are, longitudinally, densely and obliquely striated; the stria are unequal; beneath
the band the whorls are transversely striated; the strize are equal, deeply impressed, and
rather distant; the last whorl is rounded at the lower margin; the base is flat or slightly
convex, it is longitudinally, densely, and unequally striated; the strize undulate; umbilicus
none or minute; aperture subpentagonal. Axis 9 lines, basal diameter 11 lines.

Locality. The lower weatherstone beds at Quarrhouse and Minchinhampton have
yielded several specimens.

Trocuotoma, Lycett. Deslongchamps, 1842.

Rimuuuvs, D’Orb. 1839.
DirremMaria, D’ Orb. 1842.

T. Testé turbinatd, conicd ; anfractibus sepissime angulatis, in medio vittd stricta
notatis ; peripherid subangulatd ; aperturd subquadratdé ; columellé arcuatd ; basi eacavata,

GASTEROPODA. 8]

infundibuliformi, umbilicum simulante; fissurd elongata, anticé clausd, non longius ab ore,
ultimum anfractum subdepressum perforante. (Deslongchamps.)

Shell turbinated, conical; whorls usually angulated, having a band or rib encircling
the middle of each whorl; periphery subangular; aperture basal, subquadrate ; columella
curved ; base excavated, excavation large, and resembling an umbilicus; fissure transversely
elongated, closed anteriorly, but not far from the outer lip, its length being about equal to
the distance which separates it.

Our specimens exemplify the changes which the shell underwent during its advance of
growth. ‘The perfect aperture, and likewise certain oblique furrows, to be seen upon other
parts of the shell, indicate so many stages of repose, each of which probably continued a
considerable period ; the amount of advance at each stage varied from one half to three
fourths of a volution.

During the period of repose, the egress currents probably passed through the fissure ;
the edges of which are worthy of notice. The substance of the shell generally is thick,
but the edges of the fissure are extremely thin, and exhibit that irregular, ragged, or im-
perfect outline which is seen in bone or shell during the process of growth or absorption.
When, however, the animal was forming new shell in advance of the aperture, the fissure
was not advanced forward with it, but the anal siphon remained in the same position
until a considerable progress had been made in the formation of new shell. At length
that organ was withdrawn, to be protruded from the aperture, and the formation of a new
fissure immediately commenced. One specimen in our possession exhibits the fissure still
open, although the formation of new shell had proceeded beyond the old aperture to the
extent of one fourth of a volution. In this condition the outer lip is ragged and imperfect ;
and during the brief period of the formation of a new fissure, the aperture acquires exactly
the aspect of a Plewrotomaria; and it is not uncommon to find specimens in this condition.
The new shell is then very thin, and consequently is more or less crushed or imperfect.
These several removals of the anal siphon, and formation of new fissures at distant
intervals, are analogous to what is observed in Haliotis, except that in the latter genus
several perforations remain open during the formation of a new one, and their borders are
regular and smooth, not being destined to undergo the change which we observe in Zro-
chotoma. It seems indeed not improbable, that in the young state, or until three volutions
had been completed, that no fissure was formed, and that the siphon was protruded from
the aperture. This idea is founded upon the fact that those volutions are always smooth,
convex, and destitute of the encircling rib which subsequently follows the fissure. This
character is best seen by contrast in such species as in advanced growth become very
angular or step-like, as in 7! tabulata, T. discoidea, and T. extensa. 'The reader is referred
to the interresting observations on this genus, by M. E. Deslongchamps, ‘ Mem. Soe. Lin.
Normandie,’ vol. vii, pp. 99—104.

82 MOLLUSCA FROM THE GREAT OOLITE.

TrocHOoTOMA ACUMINATA, Des/. Plate X, figs. 18a, 20.

TROCHOTOMA ACUMINATA, Deslongchamps. 1842. Mém. Soc. Linn. de Normandie,
tom. vil, p. 108, pl. 8, figs. 11—15.
DITREMARIA ACUMINATA, D’Orb. 1850, Prod. Paléont., p. 301.

T. Testé conicd, spird plus minusve elatd, levi aut substriatd ; apice acuminato ;
anfractibus (7, 8) ex apice ad aperturam magis dé magis tumescentibus donec ultimus sub-
' quadratus fiat ; infind facie dilatatd, in medio cavum infunbibuliformem ferente, ad peri-
pheriam concentrice striatéd. (Deslongchamps.)

Shell conical, spire more or less elevated, smooth, or slightly striated; apex acute ;
whorls (7, 8) gradually increasing from the apex until the last whorl becomes subquadrate ;
the lower surface has a very deep but somewhat contracted cavity, which is concentrically
striated.

This is the most elevated or conical of the Great Oolite species. The last volution is
distinctly striated, the rib posterior to the aperture being very prominent ; the height and
basal diameter are about equal.

Locality. Great Oolite of Minchinhampton and Bussage ; Langrune, France.

TROcHOTOMA CoNULOIDES, Des/. Plate X, fig. 16.

TROCHOTOMA CONULOTDES, Deslongchamps. 1842. Mém. Soc. Linn. de Normandie,
tom. vil, p. 109, pl. 8, figs. 16—19.
DITREMARIA — D’Orb. Prod. Paléont., p. 301.

T. Testdé conicd, apice acuto; anfractibus (5, 6) concentricé striatis, planis; ultimo
anfractu vie ad fissuram dilatato; basi ad peripheriam convexiusculd, striata, in medio
profunde excavata.

Shell regularly conical, apex acute; whorls (5, 6) concentrically striated, flattened ;
the lower surface convex, striated, and deeply excavated.

The volutions are narrow and flattened, the encircling rib narrow and elevated ; the
figure is very oblique, the basal diameter exceeds the height by one fourth.

Our figure is somewhat reduced.

Locality. Great Oolite of Minchinhampton and Bussage; Luc, Langrune, France.

. GASTEROPODA. 83

TROCHOTOMA TABULATA. Plate X, figs. 17, 17a.

L. Testa conicd, apice acuto, anfractibus (5) tenuissimé striatis subquadratis, medio
angulatis ; anfractu ultimo subangulato; basi planato, profundé excavatd.

Shell conical, apex acute; whorls 5, very finely striated, step-like, and angulated in
their middle portion ; the last whorl is angulated, the base flattened and deeply excavated.

The sides of the volutions are nearly flat, both above and beneath the angle, which,
together with the smallness of the encircling rib, fineness of the striae, and acute apex,
serves to distinguish it from 7’ calix or 7. afinis, Desl., which is an Inferior Oolite species.
It is moderately common. Height 10 lines, basal diameter 12 lines.

Our figure is of medium dimensions.

Locality. Great Oolite of Minchinhampton.

Trocnotoma ostusa. Plate X, fig. 15a, 6.

T. Testé turbinatd; apice obtuso; anfractibus (5) conveaiusculis, striatis, basi dilatatd,
medio laté excavatd; peripheria striata.

Shell turbiated ; apex obtuse ; whorls (5) rather convex, striated, the lower surface
dilated, its middle widely excavated, periphery striated.

The encircling rib is large but depressed, and contributes to give a convex aspect to
the whorls ; the striz are large, the general figure being more turbinated, or less regularly
conical than is usual with the Zrochotome, each advance of growth was equal to two thirds
of a volution: it is by far the most abundant of the genus. Height 10 lines, basal
diameter 13 lines.

Locality. Great Oolite of Minchinhampton.

TROCHOTOMA EXTENSA. Plate X, figs. 19a, 190.

T. Testdé conicd; apice obtuso, depressd; anfractibus (4, 5) subangulatis, planis, et
levibus; basi ampla, profunde excavatda.

Shell conical; apex obtuse, depressed; whorls (4, 5) subangular, flattened, and
smooth ; base wide, rather convex; cavity large and deep.

This is by far the largest and most rare of the Great Oolite species, the base is
enormously wide, and the cavity very large. Height 16 lines, basa] diameter 30 lines.

Locality. Minchinhampton.

84. MOLLUSCA FROM THE GREAT OOLITE.

Trocnotoma piscoipEA, Roémer, sp. Plate X, figs. 10, 10a, 104, 10c.

?Trocuus DiscoipEus, Roémer. 1836. Nordd. Oolith., p. 150, t. 11, fig. 12.
= —_— D Orb. 1850. Prod. Paléont,, p. 354.
— — Bronn. 1848. Index Paleont., p. 1300.

T. Testa discoided, plano-conveva, hast concavd, lato-umbilicaté; anfractibus (3) depressis,
subconvexis, transversim lineatis, basi acutis; aperturd transverse depressd, ovata.
(Roémer.)

Shell discoidal, slightly convex, base concave, widely umbilicated ; whorls (3) depressed,
rather convex, transversely lineated, limes impressed by closely-arranged longitudinal and
very fine oblique striz ; lines upon the base acute ; aperture depressed and excavated.

We have never been able to discover an open fissure upon this small species, but the
general figure agrees with this genus so well that we have not ventured to assign it to any
other. Four lines are visible upon the lower and seven upon the upper face of the last
volution, which is angular or step-like; the first two turns are smooth and rounded : rare.
Height 3 lines, basal diameter 7% lines.

Locality. Minchinhampton ; Coral Rag, near Hildeshetm (Roémer).

Stromatia, Lam. 1801.

Sromax, Montfort. 1810.

Shell suborbicular or oblong, generally ear-shaped and depressed ; in most species the
spire is prominent, but not produced, nor elongated ; sometimes, however, it is very small,
marginal, and inconspicuous. Aperture mostly longitudinal; in some species nearly
orbicular ; in others much elongated ; always very large ; its edges entire, united, at the
upper part, and scarcely modified or altered in form by any portion of the last volution.
Volutions from two to four. (G. B. Sowerby.)

From the characters of the aperture and the presence of the carina, we have
ventured to assign the following shell to the genus Sfomatia (Lam.), from most of the
recent species of which it differs in having a depressed spire, and the lines of growth and
spiral striz very regular, and sharply defined. Should other specimens afford further
generic distinctions, we would suggest the name A/egastoma for it.

GASTEROPODA. 85

SromaTraA? (Mgeastoma), Buvigniert. Plate IX, fig. 32, 32 a.

S. Testdé semiglobosd; spird parva, depressd; anfractu ultimo transversim costulato, et
in medio carinato, carina acutd, elatd, costis longitudinalibus densis, lineis tenuissimis
impressis notatis; apertura magna semilunari; labio externo fisso ?

Shell semiglobose ; spire depressed ; last whorl with a mesial, elevated, acute carina,
crossed by longitudinal, narrow, elevated ribs—the ribs being impressed by fine encircling,
transverse lines; aperture very large; outer lip slightly notched. The shell above the
carina is flattened ; the ribs, which are perfectly regular, pass over the carina, and beneath
are decussated by fine transverse lines.

Locality. This rare shell, which attains the size of a small bean, has only been found
in the soft oolite beneath the planking on Minchinhampton Common.

We have dedicated this species to M. Buvignier, who has figured and described some
apparently congeneric forms under the name of Sfomatella carinata and S. funata. (See
‘Mém. Soc. Phil. Verdun,’ 1843, p. 19, t. 5, f. 27—80.)

Family— FIsSURELLIDE.

Fissure.ia, Lam. 1801.

FissurELLUs, Montfort, 1810.

Shell conical, base entirely open, orbicular or oval; apex central or subcentral, having
a foramen of an oval figure, central, or near to the anterior or shorter side ; surface usually
cancellated, or ornamented with ribs and lines; margin generally thickened; muscular
impression nearly continuous.

FissureLia acuta, Des/. Plate VIII, fig. 5, 5a—e.

FissuRELLA acuta, Deslongchamps, 1842. Mém. Soc. Linn. de Normandie, tom. vii,
pl. 7, figs. 22—24.
Rimvta — D Orb. 1850. Prod. Paléont., p. 303.

F. Testa conicd, altd; basi subcirculari; apice acuto, subcentral; foramine subapicial,
anticé versato, superne rotundato, inferné rimad angusté producto, striis longitudinalibus
parvis crebris, aliis transversis testam decussantibus. (Deslong.)

Shell conical, elevated, nearly circular; apex acute, nearly central; foramen a little
anterior to the apex, rounded above, narrow below; striz longitudinal, small, closely-
arranged, crossed by others, transverse and less prominent. Height 3 lines, base 3 lines.

12

86 MOLLUSCA FROM THE GREAT OOLITE.

Locality. This little conical shell ranks with the rarest productions of the Great
Oolite ; the white stone of Eastcombs and Bussage have furnished the only known English
specimens: Langrune, France.

Rimuua, Defrance, 1827.

Rimvutaria, Defrance. 1827.
Sipno, Brown. 1847.

Shell conical, base entirely open, oval; apex curved more or less posteriorly ; surface
near the anterior border with a fissure, or oval foramen, usually placed upon a prominent
longitudinal rib; the fissure does not reach the margin.

Rrmvta tTricartnata, Sow., sp. Plate VIII, fig. 2, 2a—c.

EMARGINULA TRICARINATA, Sow. 1826. Min. Con., t. 519, fig. 2.
— — Brown. 1847. Illust. Foss. Conch., p. 104, t. xlviii,
figs. 14, 14*.
— Bronn. 1848. Index Paleont., p. 457.
a _ D’Orb. 1850. Prod. Paléont., p. 303.

R. Testé parva, conica; apice postice curvato, costis tribus magnis anticis, aliis minoribus
posticis, lineis interstitialibus, transversis numerosis.

Shell small, conical; apex curved posteriorly, with three large diverging, anterior ribs ;
other smaller ribs occupy the sides and posterior part of the shell; the interstitial spaces
have numerous tranverse lines.

In this species, as in the &. Blotiz, the fissure is of a lengthened oval figure, and is cut
out of the middle and more elevated rib. Having examined the original specimen figured
in the Mineral Conchology, we are enabled to assign it to the present genus without
hesitation; in two of the specimens on the same tablet, an imperfection at the anterior
extremity of the mesial rib gave them somewhat the aspect of an Amarginula, and may have
been the reason, probably, for assigning both this and R. clathrata with that genus.

Locality. Ancliff: two specimens have, likewise, been found at Minchinhampton.

Rimvuta ciatHrata, Sow., sp. Plate VIII, fig. 1, la—e.

EMARGINULA CLATHRATA, Sow. 1826. Min. Con., t. 519, fig. 1.

2 — GotpFussi, Roémer. 1836. Nordd. Oolith., t. 19, fig. 23.

2 — — Goldfuss. 1845. Petref., t. 167, fig. 15.
SrpHo cLaTHRATA, Brown. 1847. Illust. Foss. Conch., p. 103, t. 48, figs. 1, 2.
RimuLa — Morris. 1843. Catalogue of British Fossils, p. 160.

a _ Bronn. 1848. Index Paleont., p. 1088.
— - D’ Orb. 1849. Prod. Paléont., p. 303.

GASTEROPODA. 87

hk. Testd conicé; apice posticé curvato; ambitu ovali; rimd angustd, costis majoribus
radiantibus (circa 18), minoribus tranversis decussatis.

Shell conical; apex somewhat spiral, and curved posteriorly; base oval, foramen
narrow, lengthened, and rather distant from the anterior margin; ribs radiating (about 18
in number), crossed by others, smaller and transverse.

The indifferent condition of the original specimen will account for its having been
placed with HLmarginula.

Locality. Ancliff and Minchinhampton ; at the latter place it occurs only in the bed
of planking : it is rare.

Rimuxa Buori, Des/., sp., Plate VIII, fig. 3, 3a, 4, c.

Emarainuta Buorri, Deslongchamps. 1842. Meém. Soc. Linn. de Normandie, tom. vii,
pl. 10, figs. 1—3.
—_ — JD Orb. 1850. Prod. Paléont., p. 303.

R. Testé parva, crassa, conicd; apice posticé curvato, lateribus subplanis; costis radi-
antibus magnis 15 et parvis 14 alternis; sulcis punctis tranversalibus magnis notatis.

Shell small, thick, conical ; apex curved posteriorly, the sides flattened ; ribs radiating,
15 larger and 14 smaller, alternating—the three larger anterior ones being the most
prominent; the transverse sulci of the interstitial spaces are large.

This species bears a considerable resemblance to &. tricarinata; but it is more com-
pressed laterally, the three large anterior costz are less divergent, and the form of the base
is a longer oval. The 2. tricarinata is likewise destitute of the smaller ribs, and has more
numerous transverse lines.

Locality. It occurs rarely at Ancliff; and is likewise scarce in the shelly roestone of
the Inferior Oolite at Leckhampton Hill, Cheltenham. A single specimen, badly preserved,
has also been procured at Minchinhampton. Colleville, Calvados.

Emarcinuta, Lam., 1801.

PaTELLa sp., Linn.
Emarainuvus, Montf. 1810.

Shell conical; apex usually curved posteriorly, base entirely open, orbicular or oval ;
its anterior margin having a vertical fissure more or less lengthened; surface ornamented
with ribs, and decussated.

88 MOLLUSCA FROM THE GREAT OOLITE.

EMARGINULA scALARIS, Sow. Plate VIII, figs. 4, 4a, 4, c.

EMARGINULA SCALARIS, Sow. 1826. . Min. Con., t. 519, figs. 3, 4.
os _ Brown. 1847. Illust. Foss. Conch., p. 103, t. xlviii, fig. 5.
— — Bronn. 1848. Index Paleont., p. 456.
a _ D’ Orb. 1850. . Prod. Paléont., p. 303.

2 oS — Desl. 1842. Meém. Soe. Lin. Norm. vii. p. 125.

L. Testa parva, conicad ; ambitu suborbiculari; apice plus minusve postico ; costis levibus
radiantibus et transversis decussantibus; rimaé elongatd lata.

Shell small, conical; base nearly circular; apex elevated, more or less posterior ; ribs
radiating, smooth, transversely crossed by others. The radiating ribs are narrow, but
are somewhat larger than those which are transverse; the mesial radiating rib bifurcates
near the margin, forming a lengthened and wide fissure.

Locality. Ancliff and Minchmhampton ; at the latter place it is very rare: Langrune,
France.

Family—PAtTELLIDE.

Pateia, Linneus. 1758.

Pate uaria, Lhwyd. Lith. Brit. Ich.
Hetcion, D’ Orbigny.

Shell ovately conical, with an oblong or oval base ; apex subcentral, or inclining towards
the anterior side ; internal surface smooth ; muscular impression horse-shoe shaped ; margin
of the aperture entire.

PateLLa cincuLATA, Goldf. Plate XII, figs. 4, 4a—d.

PaTELLA CINGULATA, Goldfuss. 1843. Petref., t. 177, fig. 11.
HELCION _ D’ Orb. 1850. Prod. Paléont., p. 358.

P. Testé conicd, ambitu ovali, verticé subacuto, elato, erecto, antemediano; striis concen-
tricis confertis wregularibus.

Shell conical, base oval, apex subacute, elevated, erect, placed anterior to the middle
line of the shell, with encircling, irregular, closely-arranged striz.

This may be regarded as one of the most abundant and characteristic of the Patella of
the Great Ooolite. It occurs in all the shelly beds, but more especially in the white stone
of Eastcombs and Bussage, near Brimscombe. The dimensions vary from the size of a
duck-shot to a diameter of seven lines; and, from the great thickness of the shell, it is
usually well preserved. The height is equal to two thirds of the longer basal diameter.

GASTEROPODA. 89

PATELLA RuUGOSA, Sow. Plate XII, figs. 1, la—y.

PAaTELLARIA SIMA, Lhwyd. 1760. Lith. Brit. Ich., t. 8, No. 436.!
THe PaTEuitse,. Park. 1811. Org. Rem., vol. iii, p. 50, t. 5, fig. 21.
PaTELLA RUGOSA, Sow. 1816. Min. Con., t. 139, fig. 6.
— _ Fleming. 1827. Brit. Anim., p. 288.
= — Brown. 1849. Illust. Foss. Conch., p. 104, t. xlviii, fig. 18.
_ _ Morris. 1543, Cat. Brit. Foss., p. 155.
— ANCYLOIDES, Sow. 1824. Mun. Con., t. 484, fig. 2.
— —_— Brown. Ilust. Foss. Conch., p. 105, t. xlviii, figs. 27—29.
(=e Trssontl, Deslongchamps. _ Mém. Soc. Linn. de Normandie, vol. vii, t. 7, fig. 3.
HeLcion ruGosa, D’Orb. Prod. Paleont., p. 303.

P. Testa ovata, postice converd, anticé subconcavd, apice depresso, versus marginem
anticum inflexo ; costulis radiantibus crebris, interstitiis lineatis ; striis alteris transversis
decussantibus, antice congestis, testamque corrugantibus, postice remotis.

Shell ovate, posterior side convex, anterior rather concave; apex depressed, inclined
towards the anterior margin ; the longitudinal radiating ribs are closely arranged, with fine
lines between them, and decussated by encircling striz, which, upon the anterior side, are
corrugated or compressed closely together ; posteriorly they are remote.

The aspect of this shell varies considerably, even in specimens obtained from the same
quarry ; and these differences are irrespective of those produced by the various stages of
growth. Some approach to the circular form, and in such the apex is more central,
elevated, and less curved forwards; others, which are a longer oval, have the summit more
beak-like and depressed. he different degrees of magnitude in the radiating cost, and
the depth to which they are impressed by the encircling striae, likewise contribute to the
varieties of aspect. ‘The greater number of specimens obtained from the quarries at
Minchinhampton Common have a rugose aspect, but those from the quarries situated to
the north of the vale of Brimscombe are usually different ; the shell becomes very thin,
the form is more depressed, and the surface is nearly smooth, the ribs being faintly marked,
and the encircling stria scarcely discernible. When very young, and not exceeding 6
lines in length, the figure is more depressed, of a longer oval, nearly smooth, and the apex
is turned, and even slightly twisted to the right side, constituting the Patella ancyloides of
the ‘Mineral Conchology.’ It is rare to obtain the shell so small; and the Ancliff
specimen, upon which the species was founded, is, in common with all the Great Oolite
shells of that locality, extremely small, but the number of intermediate sizes obtained, leave
no doubt of its identity. It occurs, indifferently, in all the shelly beds. Our largest
specimen has a length of 23 inches, a width of 2} inches, and a height of 13 lines.

Locality. Minchinhampton Common; Bussage; Ancliff.

Found also in the Stonesfield slate (Sowerdy) ; in the roestone of the Inferior Oolite at

1 « Patellaria sima, fusci coloris, cancellata major. E lapicidina Stunfeldiensi,” p. 24.

90 MOLLUSCA FROM THE GREAT OOLITE.

Leckhampton Hill, near Cheltenham (Buckman); and in the Great Oolite of Langrune,
Luc, Ranville, &c., Normandy (Deslongchamps).

The Patella Tessonii (E. Desl.), which is referred to this species with some doubt, was
obtained from the Inferior Oolite of Moutiers-en-Cinglais by M. Tesson.

PaTELLA PARADOXA. Plate XII, figs. 2, 2a, 6.

P. Testé suborbiculatdé, apice depresso, versus marginem anticum inflexo, latere antico
concavo, postico convexo ; costis radiantibus, elatis, rotundatis, undulatis, transversim striatis,
et distantibus, costis posticis 9 magnis, lateralibus obscuris, anticis congestis et corrugatis.

Shell suborbicular, apex depressed, turned towards the anterior margin ; anterior side
concave, posterior convex; ribs radiating, large, distant, elevated, rounded, undulated and
impressed by transverse strize; the posterior coste, about 9 in number, are large, those
upon the sides of the shell are depressed and obscure ; the anterior ribs are congested and
corrugated.

The general aspect of this smgular shell reminds us of Pafella rugosa, which it follows
somewhat in its varieties of aspect. When young, the few posterior cost are prominent,
but the sides of the shell are smooth, and the general figure is more depressed and
elongated ; the costa are much larger than in P. rugosa, more distant, and, im consequence,
much fewer; and the entire shell has a wrinkled and very rugose aspect. The colours are
usually more or less preserved.

Locality. This may be considered as the most rare of the Minchinhampton Patelle.
The few examples obtained have been found in the planking, or in the equivalent white
stone of Hasteombs and Bussage. ‘The young form, were it known only by a single
specimen, would probably be regarded as a distinct species; the older specimens attain
nearly the dimensions of a middle-sized P. rugosa.

Paretua suncata, Deslongchamps. Plate XII, figs. 8, 3a, 4.

PaTRLLA SULCATA, Deslongchamps. 1842. Mém. Soc. Linn. de Normandie, vol. vii,
p. 115, t. 7, figs. 9—11.
Hetcion — D Orb. 1850. Prod. Paléont., p. 272.

P. Testé subellipticd, conico-depressd; apice recto; costis elatioribus radiantibus,
inequalibus, sguammato-rugosis, sulcis profundis interpositis, margine subcrenato.

Shell subelliptical, conical, but depressed; apex erect; ribs elevated, radiating,
unequal, squamose or rugose, with deep interstitial spaces; margin somewhat crenated.

The costee do not increase in size materially as they approach the margin, and the
additional ribs which are added with increase of growth equal the others in size. ‘This

GASTEROPODA. 91

species possesses a general resemblance to P. Audbentonensis, but the ribs are much more
elevated, closely arranged, and rugose. The figure given by M. Deslongchamps is more
elevated, but possesses no other essential distinctive character. Length 9 lines, breadth
7 lines, height 3 lines.

Locality. Rare, in the planking of Minchinhampton Common; also found in the
Inferior Oolite of Port-en-Bessin (Deslongchamps).

PATELLA STRIATULA. Plate XII, figs. 5, 5a, 0.

P. Testé parvd, conicd, obtusa; ambitu ovali ; costis radiantibus, tenuioribus, crebris,
flecuosis et nodulosis ; lineis incrementi irregularibus.

Shell small, conical ; apex obtuse ; base oval ; with ribs radiating, fine, closely arranged,
waved, and nodulated; lines of growth irregular.

This species is more elevated than P. Audbentonensis, and the apex more obtuse; the
costz are likewise finer and more closely arranged.

Locality. In the soft shelly Oolite beneath the planking at Minchinhampton, where
it is rare.

Patetia Rormeri. Plate XII, figs. 6, 62, 0.

P. Testa ellipticd, depressé ; apice subcentrali ; costis (30) radiantibus elatis ; lineis
interstitialibus numerosis; stris transversis impressis; lineis incrementi irregularibus
paucis.

Shell depressed, elliptical; apex subcentral, with 30 radiating and elevated ribs ; inter-
stitial lines numerous, the whole being crossed and impressed by striz; lines of growth
irregular and few.

This elegant little species is sometimes nearly discoidal, the central portion being most
frequently denuded of costz; the form is more nearly circular than P. Aubentonensis, and
more depressed ; the cost are more elevated and less rounded, the interstitial spaces
being much deeper. The longer diameter rarely exceeds 9 lines, the elevation being
about 2.

Locality. It is moderately rare, but not confined to any one shelly bed, in the vicinity
of Minchinhampton.

PATELLA AUBENTONENSIS, Archiac. Plate XII, figs. 7, 7a, 4, ¢, d.

PatTetLa AUBENTONENSIS, Archiac. 1843. Mém. Soc. Géol. de France, vol. v, p. 377,
t. 28, fig. 8.
HELCION _ D’ Orb. 1850. Prod. Paleont., p. 304.

92 . MOLLUSCA FROM THE GREAT OOLITE.

P. Testi conicd, depressé ; ambitu ovali; apice acuto, antemediano ; costulis radi-
antibus inequalibus trregularibus, flexuosis ; striis transversis tenuissimis, irregularibus.

Shell conical, depressed; base oval; apex acute, placed anterior to the middle of the
shell; ribs radiating, unequal, irregular and waved; strize transverse, irregular, and
very fine.

The radiating ribs are sometimes only visible coal the margin ; iid Gad! of itil
are few and uncertain ; as in the other Pated/e, the degree of elevation varies considerably,
the apex approaching more nearly to the anterior border in such as are depressed ; the
colours are sometimes partially preserved.

Locality. It is not uncommon, and occurs in all the ne beds of the Great Oolite
near Minchinhampton. Our largest specimen is 14 inches in its longer diameter.

M. D’Archiac describes this species as eet in the Great Oolite of Aubenton,
France, where it is rare.

PATELLA SUPRAJURENSIS, Buv. Plate XII, figs. 9, 9a.

? PATELLA SUPRAJURENSIS, Buvignier. 1843. Mém. Soc. Philom. de Verdun (Meuse),
pl. 5, fig. 10.

P. Testé ovato-depressd ; apice subcentrali; ambitu ovali; striis increment trregu-
laribus, distinctis ; striis concentricis tenuissimis crebris.

Shell ovate, depressed ; apex subcentral; base oval; lines of growth irregular, strongly
marked ; concentric striz closely arranged and very fine.

The absence of radiating coste sufficiently separates this from P. chemin the
general figure of which it nearly resembles; the lines of growth are likewise much more
strongly marked.

Locality. It is comparatively rare, and is not confined to any of the shelly beds of the
Oolite at Minchinhampton. Found also in the Portland limestone of Varennes. (Buv).

PATELLA ARACHNOIDEA. Plate XII, figs. 8, 8a, 0.

P. Testé parva, ellipticd et conicé; apice acuto centrali; costulis longitudinalibus minutis
et distantibus; lineis transversis numerosis, elatis et trregularibus.

Shell small, elliptical and conical; apex acute, central; with longitudinal, minute, and
distant ribs ; transverse lines very numerous, elevated, and irregular.

This small species has an elevated, acute apex, and displays under the magnifier a
beautiful net-work kind of surface ; the encircling lines are three or four times more dense
than the longitudinal elevations. The form is nearly that of Pileolus plicatus, but more
acute, and the character of the surface is altogether different.

Locality. 'The shelly beds at Quarhouse, which correspond to the planking of Min-
chinhampton Common, have furnished our specimens.

GASTEROPODA. 93

PaTELLA INoRNATA. Plate XII, figs. 11, 11a.

P. Testa elliptica, levissimd, lateribus subcompressis; apice elato, erecto, subacuto, et
postmediano; latere antico concavo, postico recto.

Shell elliptical, very smooth, the sides rather compressed; the apex erect, elevated ;
subacute, and situated posterior to the middle of the shell; anterior side concave, posterior
straight.

The figure is a lengthened oval, the anterior side being rather depressed and pro-
duced; the concavity anterior to the apex, presents some resemblance to P. nitida
(Deslongchamps); but in that shell the anterior side is much the shortest. P. nitida is,
likewise, much more nearly orbicular and conical, the vertex being distinctly curved
forwards. The smaller specimens have a more depressed figure, the anterior cavity being
scarcely perceptible.

Longer diameter 10 lines, shorter diameter 8 lines, height 5 lines.

Locality. It occurs in all the shelly beds, but is not very common in the Minchin-
hampton district.

PATELLA NANA, Sow. Plate XII, figs. 10, 10a.

PaTELLA NANA, Sow. 1824. Min. Con., t. 484, fig. 3.

— — Fleming. 1827. Brit. Anim., p. 288.

— — Morris. 1843. Cat. Brit. Foss., p. 155.

—_ — Brown. 1849. Illust. Foss. Conch., p. 105, t. xlvi, figs. 24—26.
Hertcion nana, D’Ord. 1850. Prod. Paléont., p. 303.

P. Testd parva, ellipticd, conicd, levissimad; apice submediano, erecto, obtuso.

Shell small, elliptical, conical, very smooth ; apex nearly mesial, erect and obtuse.

The figure approaches near to P. cingulata, but it is usually a longer oval, and slightly
compressed at the sides; in the young state the apex is more obtuse and depressed, the
form being then a longer oval. Many of the larger specimens are scarcely to be distin-
guished from P. cingulata, except by the absence of encircling strie; and in badly
preserved specimens the strize are nearly obsolete. P. xana may, therefore, possibly be
only a variety of P. cimgulata; they occur in the same beds, and are equally numerous. It
is true that good specimens of each species are sufficiently distinct; but knowing the
variations to which the shells of this genus are subject, we have thought proper to allude
to the possible specific affinity. The size never equals that of the larger specimens of
P. cingulata.

Locality. Minchinhampton Common: found also in the Oolite of Ancliff, near
Bradford, Wilts.

13

94 MOLLUSCA FROM THE GREAT OOLITE.

Durstonecuampsia, M*Coy,' 1849.

D. Testé orbiculaté, conicd; apice subcentrali versus marginem anticum inflexo; costulis
radiantibus, antico sulco lato longitudinali, in laminam appendiculatam producto.

Shell suborbicular, conical; apex acute, subcentral, curving slightly forwards; with a
wide longitudinal anterior sulcus, produced into a rounded lobe.

This genus has been separated from the Mefoptoma of Phillips, on account of the pro-
longation of the anterior excavated side into a rounded process, which it is presumed does
not exist in that genus; the surface is highly ornamented, but the A/etoptome are smooth.
Two species are known, one of which is the Patella appendiculata of M. Deslongchamps
(Mém. Soc. Linn. de Norm. vii, pl. XI, f. 1, 2); a somewhat oval shell, having simple,
large radiating costae, and the present species which has a cancellated surface. M. Deslong-
champs remarks, that in all the patelloid shells, except the Patel/z, the apex is turned
posteriorly, and if there exists any notch, furrow, or peculiar mark, it is always found on
the anterior side, and never on the side to which the apex is curved. The situation of
the furrow anteriorly, in the P. appendiculata, or on that side to which the apex of the
shell is turned, as in the Pated/e, would indicate an important modification in the mantle,
or some other organ of this mollusc.”

DESLONGCHAMPSIA EUGENEI, J/‘Coy. Plate XII, figs. 13, 13a.

D. Testa suborbiculatd, conicd; apice subcentrali, acuto, sulco antico lato striato; costulis
numerosis, longitudinalibus, transversisque decussantibus; sulcis interstitialibus profundis.
Shell suborbicular, conical; apex subcentral, acute, anterior sulcus wide, striated; ribs

' Professor M‘Coy having kindly forwarded his notes on this genus, intended for publication, we have,
with his permission, inserted them:
* DEsLoNGcHAMPSIA, M‘Coy.
** Shell convex, radiatingly ridged; apex eccentric towards the anterior end; a concave spoon-shaped
hollow extends from the apex, gradually inclining to the outer margin, which it carries downwards into a
small rounded lobe.

‘This shell, like Phillips’s genus Metoptoma, has a triangular hollow extending from the apex to the
front margin, therein differing from Patella ; the present genus differs from Metoptoma in its ridged surface,
and from it and Patella in the front margin being produced downwards into a rounded lobe. This latter
structure would prevent the firm adhesion of the shell! This group has been recognised by M. E.
Deslongchamps, but not characterised, as he only knew one species. Having obtained another, perfectly
distinct, but identical in generic characters, I have characterised the genus, and dedicated it to M.
Deslongchamps, to whom I think the merit of recognising it in the first instance belongs. Any one who
reads the charming passage in M. Deslongchamps’ Memoir (p. 119, vol, vii of the ‘Mém. de la Soc. Linn.
de Normandie’) will understand the pleasure with which I dedicate this species to his son Eugene, under
the name of Deslongchampsia Eugenei.”’—(M‘Coy’s MS. notes, 1849.)

2 In the specimen in the British Museum, (figured Plate XII, fig. 13,) the apex is imperfect, but the
direction of the strize appear to indicate a reverse or posterior direction of the apex, and, consequently,
analogous to the Fissurellide.

GASTEROPODA. 95

elevated, numerous, transversely crossed by others of nearly equal size; and interstitial
spaces deep.

The anterior sulcus has a hollowed or spoon-shaped figure, and, like the other portion
of the surface, is cancellated; but the longitudinal ribs are more closely arranged: the
number of ribs in the circumference is about 50.

Height 3 lines, basal diameter 6 lines, width of anterior sulcus at the margin 2 lines.

Locality. It is very rare, and has been obtained only in the white stone of Easteombs
and Bussage: we are not aware that more than three examples have been found.

Umpretta?P Hamptonensis, Plate XI, figs. 12, 12a.

U. Testé parva, depressd; ambitu orbiculari; apice obtuso, depresso, centrali; costis
radiantibus, levibus, paucis, irregularibus, fleauosis; sulcis interstitialibus separatis.

Shell small, depressed; base orbicular; apex obtuse, discoidal, and central; ribs
radiating, smooth, few, irregular, and waved ; separated by interstitial sulcations,

This little shell is sometimes perfectly flat, but usually somewhat convex; it is
extremely thin, and as the under surface has not been fully disclosed, it must be referred
to Umbrella with some degree of doubt; it may, however, be probably considered as
related to the patelliform shells, The basal diameter rarely exceeds 4 lines.

Locality. The soft shelly Oolite beneath the planking usually furnishes it in the
neighbourhood of Minchinhampton : it is rare.

ORDER—OPISTHOBRANCHIATA, MZ. Edwards.

Family—Bv Liv.

Buia, Linn.

Shell oval, ventricose, or cylindrical, generally thin and fragile, the last whorl more or
less enveloping the preceding ones; spire umbilicated, or slightly produced ; aperture
large, the whole length of the shell, narrow above and dilated below; outer lip sharp.

The specimens of this genus from the Great Oolite are very few, and in a condition less
satisfactory than could be wished. They have been obtained (with a single exception) from
the upper beds of the formation to the east of the town of Minchinhampton. These beds
usually consist of hard gray or brownish calcareo-siliceous sandstones, sometimes con-
eretionary, and contain Ceromy@e, certain Pholadomye, and other shells which are never
found in the lower and more shelly beds. The Bulle are rare, but might possibly become
less so, were the stone brought more under the inspection of workmen and connoisseurs ;
but being lifted only in small quantities during the winter season, from little excavations

96 MOLLUSCA FROM THE GREAT OOLITE.

for road mending, and being, moreover, a very intractable material, none but a persevering
local collector can be expected to obtain even a partial knowledge of its fossil contents.
His reward will usually be, as in the present instance, mere imperfect casts, which contrast
unfavorably with the products of the richer and softer shelly beds.

Buiua unpuLata, Bean. Plate VIII, figs. 8, 8a.

BuLLA UnDULATA, Bean. 1839. Mag. Nat. Hist., p. 61, fig. 22.
— — Morris. 1843. Cat. Brit. Foss., p. 140.

B. Testé ovati, ventricosé ; apice umbilicato; umbilico contracto; labro interno
sinuato ; apertura magna, superné angustatd, inferné dilatiore ; striis incrementi numerosis,
longitudinaliter undatis.

Shell ovate, ventricose ; apex umbilicated; umbilicus contracted ; inner lip sinuated ;
aperture large; narrow above, wider below; strie of growth numerous, longitudinally
undulated.

Breadth, two thirds of the length.

The specimen figured by Mr. Bean in the ‘ Magazine of Natural History,’ from the
Cornbrash of Yorkshire, is about half as large again as the shell here described, and the
inner lip is not so much sinuated ; but in other respects it is very similar.

The general features of this shell bear a considerable resemblance to the Bulla elongata,
Phillips, ‘Geology of Yorkshire,’ pl. iv, fig. 7; but it is much less elongated than that
species.

Locality. Our specimen was obtained from the upper portion of the Great Oolite
formation, in a bed of hard brown shelly sandstone, 95 feet above the Fullers-Harth, one
mile and a half east of Minchinhampton. Rare.

Butta Loxiotum. Plate VIII, figs. 16, 16a, 164.

B. Testd cylindro-ventricosd; aperturé angustd, basi subdilatatd, vertice subcontracto,
profundé excavato, margine elato, et rotundato.

Shell cylindrical, but ventricose ; aperture narrow, its base rather dilated, apicial cavity
somewhat contracted and deeply excavated; the mamillary apex of the whorls being
large, and rising considerably from the base of the cavity, but not so high as the outer
margin; margin of the cavity elevated, narrow, and rounded.

The figure is nearly barrel-shaped, both the extremities appearing truncated and
narrower than in the middle part. The character of the apicial cavity resembles that of
several species of Cylindrites, figured upon the same plate; we have not been able to expose
the base of the columella; but, judging from the general figure of the shell and of the

GASTEROPODA. 97

aperture, we prefer to regard it as a Bulla. Upon comparing approximate forms it will
be found that the figure of the base and cavity of the vertex is much wider than in
C. pyriformis; the cavity is much more contracted and deeply excavated than in C. du/-
latus; a third shell, which more nearly approximates in form to our species, is the
Bulla Hildesiensis, figured by Roémer, (Verst. Nord. Ool. Geberges, t. ix, fig. 26,) in
which, however, the form appears to be more elongated and the aperture more expanded
towards the base.

Our shell would seem to be rare; we have obtained it in one small excavation only,
about 100 feet above the Fullers-Earth, in concretionary sandstone: the disintegrating
action of frost has enabled us to detach two specimens, and we have vainly endeavoured to
extricate several others from a matrix harder than themselves,

Axis 7 lines, transverse diameter 53 lines, diameter of the cavity 2 lines.

Locality. A superficial excavation one mile east of Minchinhampton.

Family—ACTHONIDE.
Cy1inpRrites—JVov. gen.
ACTON sp., Sow., D’ Ord.

Testa subcylindrica vel ovatd, spird parvd ; anfractibus plerumque planis, marginibus
acutis, anfractu ultimo cylindraceo, apertura elongatd, superné linearis, inferné integra
et rotundatd ; columellé ad basim cortortd, labro dextro tenui ad basim crassiort.

Shell smooth, subcylindrical or ovate; spire small; whorls usually flattened, with acute
margins; the last whorl cylindrical; aperture lengthened; linear above; rounded and
entire at the base; columella rounded, twisted near to the base, and slightly directed
outwards ; right lip thin, but thicker at the base.

The cylindrical figure, flattened and nearly concealed volutions, their acute margins,
the linear aperture and columella directed outwards at the base, are the characters which
entitle this group to be separated from Actzeon (‘Tornatella Lam.), and constituted a new
genus, it is in fact a Pyramidella in all but the basal notch; some of the species will be
found to approach to the Cones, others the Bulla, in each case more nearly than to Acton.
Species of this genus also occur in the Inferior Oolite, but they are perfectly distinct from
those which are here described.

All the species of this genus have smooth shells ; in Acteeon most of the species are
transversely striated or punctato-striate.

Mr. Sowerby, in the description of Acteon cuspidatus, remarks, “So novel is the
contour of this little shell, that it is with difficulty compared to any before known; it
agrees, however, with the essential characters of Actaon, but differs in general form, and

98 MOLLUSCA FROM THE GREAT OOLITE.

in having a plain surface ; it comes nearer in shape to Volvaria, but that has a truncated
or notched base, and crenated lip to the aperture, besides several plaits upon the columella.”

It has been proposed to form a new genus of it, to be called Cylindrites, but the
following species (4. acutws) having a conical spire, connects it with Acteon Noe. ‘Min.
Con.’ 5, p. 77, 1825.

Notwithstanding their general resemblance to Actzeon, we believe the species here
described to be generically distinct from the typical forms of that genus, and have there-
fore proposed to retain the name Cylindrites for them.

The genus may be divided into two sections :

A. Species with the spire elevated and acute.

B. Species with the spire depressed and mammillated.

The species belonging to the second section appears to pass into the Acteonellze of the
cretaceous system.

A. Species with the spire elevated and acute.

CyLinpRitEs acutus. Sow. sp. Pl. VIII, fig. 9, 9 a, 4.

ACTON acutus, Sow. 1824, Min. Con., t. 455, fig. 2.
— _— Morris, 1843. Cat. Brit. Foss., p. 138.
—_— ~ D’ Orb. 1850. Prod. Paléont., p. 299.
wee — Bronn. 1848. Index Palzont., p. 10.

Lesta subcylindricd, spird conicd, apice acuto, anfractibus (4) planis seu subconvewis ;
anfractu ultimo margine rotundato.

Shell subcylindrical, spire conical, apex acute; whorls (4) flat or slightly convex; the
last volution rounded at its upper margin.

Locality. This shell occurs in much greater numbers than all the individuals of the
other species put together; it may, in fact, be considered as one of the most common
univalves in the Great Oolite near Minchinhampton.

It occurs in the Oolite at Ancliffe, Wiltshire, whence the original specimens were
obtained, which are figured and described in the ‘ Mineral Conchology,’ and Mr. J. de C.
Sowerby has kindly allowed us the use of the same for examination and comparison.

CrLinprites cuspipatus. Sow. sp. Pl. VIII, fig. 10, 10a.

AcTMON cusPpipaTus, Sow. 1824. Min. Con., t. 455, fig. 1.
_— — Morris. 1843. Cat. Brit. Foss., p. 138.
_— —_ D’ Orb. 1850. Prod. Paleont., p. 299.
_ — Bronn. 1848. Index Palzont., p. 10.
TORNATELLA cusPIDATA, Deslongchamps. Mém. Soc. Linn. de Normandie, vol. vii,
p- 136, t. x, figs. 25, 26.
_ _ Brown. Illust. Foss. Conch., p. 85, t. xliii, figs. 11, 2.

GASTEROPODA. 99

Testa cylindrica, spiré parva sub-inversd, apice mammillato ; anfractibus angustis planis ;
anfractu ultimo margine rotundato.

Shell cylindrical; spire small, somewhat inversed in the latter volutions; apex mam-
millated ; volutions narrow, flattened ; the last one rounded at the upper margin.

The upper margin of the last whorl rises as high as the one or two preceding ones,
leaving their edges exposed so that the small mammillated apex and one or two first
whorls seem to rise from a cavity. In the character of its spire this shell forms a passage
to the remaining species, in none of which does the apex of the spire rise higher than the
margin of the last whorl, the vertex is consequently more or less bow]-shaped or concave,
the volutions never being entirely concealed, but exhibiting their upper edges.

This is a rare shell, and, with the preceding species, is found indifferently in all the
beds of shelly oolite belonging to this Formation.

Locality. Minchinhampton Common ; Ancliff, Wiltshire; Langrune, France.

Cyutinprites ancuLatus. PI. VIII, fig. 11, 1l a, 4.

Testé cylindricd ; spird mediocriter elatd, sub-concava ; apice acuto; anfractibus (8)
angustis superné angulatis.

Shell cylindrical ; spire moderately elevated, with rather concave sides, and an acute
apex ; volutions eight, narrow and angular in their upper part.

The general figure of this shell is somewhat shorter than C. acutus, the volutions are
very narrow and angular, which, together with the somewhat concave spire, give it a well-
marked form; it is more common than the last species.

Locality. The upper beds of the Great Oolite near Minchinhampton.

Cyttnpritms autus. Plate VII, figs. 12, 12a, d.

C. Testa cylindrica, subfusiformi, spira elaté; anfractibus (8) planis latis.
A cylindrical, subfusiform shell, with an elevated spire, and eight flattened, and rather
broad, volutions.
In this species the spire is flattened with an acute apex, which is equal in length to a
third portion of the entire shell.
Locality. Minchinhampton Common. It is moderately rare.

100 MOLLUSCA FROM THE GREAT OOLITE.

B. Species with the spire depressed and mammillated.

A, CYLINDRICI.

CyLinprites cyrinpricus. Plate VIII, figs. 19, 19a, 4, c.

C. Testa cylindrica, elongata, truncata; spird depressd, vel obsoletd, vertice subconcavo;
anfractibus angulatis, anfractu ultimo margine superiore acuto.

Shell cylindrical, lengthened, truncated; spire depressed, almost obsolete; vertex rather
concave ; volutions angular, the last one with the upper margin acute.

This is the most elongated and truncated species of the group, and might easily be
mistaken for a specimen with an imperfect spire: in well-preserved specimens the apex may
be observed to consist of two volutions, which rise above the others, forming a mammillated
summit; the base of the shell is much contracted and lengthened.

Locality. tis rare, and has been found only in the “ planking” of Minchinhampton
Common.

Crinprites Excavatus. Plate VIII, figs. 17, 17a, 6.

C. Testa cylindrica, truncata; spird inversd, apice mammillato, vertice magno profunde
excavato; anfractibus numerosis, marginibus acutis notatis; anfractu ultimo subconvexo,
margine superiore acuto, subcontracto; cetere note desunt.

Shell cylindrical, truncated; spire inverted; apex mammillated, vertex large, deeply
excavated ; whorls numerous, their upper margins acute; the last whorl somewhat convex,
with an acute margin, and slightly curving inwards. Base not seen.

The specimen being rather imperfect at the base prevents our ascertaining with
exactness the length of the species, which would appear to be intermediate to C. bullatus
and C. Thorentei, but is certainly less elongated than the latter species ; the vertex is large
and very deeply crateriform, the apex not rising much above the centre of the deep con-
cavity, and not so high as the margin of the last volution, the edges of the numerous whorls
being visible in the concavity.

Tocality. This example and a section of another are all which have been obtained ;
they occurred in the upper series of the Great Oolite formation, a little higher than the
hard cream-coloured limestone, and in a rock of nearly equal compactness, two miles east
of Minchinhampton, on the road to Cirencester; the same rock, also, contains C. acutus
and C. angulatus, but the intractable nature of the material renders it extremely difficult to
obtain good specimens.

GASTEROPODA. 101

Cyiinpritrs Brevis. Plate VIII, figs. 13, 13a, 6.

C. Testa parva, cylindro-truncatd, apice amplo, plano, margine acuto ; lateribus planis ;
apertura ad basin sub-eapanso.

Shell small, truncated, cylindrical, vertex large, flattened, its margin acute; sides of
the shell flattened, marked with lines of growth; aperture moderately expanded towards
the base. :

This is the most truncated species of the genus in the Great Oolite. The vertex is
very wide, almost perfectly flattened; but the acute edges of the volutions are visible, and
likewise the minute mamillary apex. These characters, together with the short figure,
serve to distinguish it from C. cylindricus, Plate VIII, fig. 19, the shell which most nearly
approaches to it. Axis 5 lines, diameter of vertex 3 lines.

Locality. Minchinhampton Common, where it is very rare.

Cyuinprites THorENTI, Buvign., sp. Plate VIII, figs. 22, 22a, 4, c.

Butta THoRENTEA, Buvignier. 1842. Geéol. des Ardennes, p. 535, t. v, fig. 9.
— — Buvignier. 1843. Meém. Soe. Philom. Verd., ii, t. 5, fig. 11.
— — D’ Orb. 1850. Prod. Paléont., p. 304.
— ELoNGATA, Thorent. Mém. de la Soc. Geol. de France, iii, p. 258. (Not
Phillips, Geol. of Yorkshire.)

C. Testa subcylindricd, lateribus convexiusculis, spird parvd, depressd, contractd; anfrac-
tuum marginibus solim easertis; aperturd angustd, columella ad basin uniplicatda.

Shell subcylindrical, the sides somewhat convex, smooth, or slightly marked by the
lines of growth; spire small, depressed, and contracted ; the whorls with their margins
only visible ; aperture narrow, basal fold of the columella large.

The apicial excavation is more contracted than in either of the other species; the apex
is large, but does not rise quite so high as the outer margin; the shell, in its general figure,
is elongated and contracted at both the extremities. Axis 9 lines, greatest transverse
diameter 4 lines, diameter of the terminal excavation 1 line.

Locality. Minchinhampton Common; it occurs in the bed of planking, but is
very rare.

M. A. Buvignier states that this fossil is found in the white limestone of the Great
Oolite in the environs of Rumigny. M. Thorent has also found it near Aubenton, and
mentions it in the Memoir above referred to, under the name of Bulla elongata, as
occurring in the Coral Rag; this is considered to be an error by M. Buvignier, as the bed
contaming it, in following its course into the Ardennes, is undoubtedly beneath the
Oxford Clay.

14

102 MOLLUSCA FROM THE GREAT OOLITE.

B, PyRirormt.

CyLinpritEs BULLATUS. Plate VIII, figs. 18, 18a, J, ¢.

? Conus? minimus, Archiac. 1843, Mém Soc. Geol. de France, tom. vy, t. 30, fig. 9.
AcT&0ON MINIMUS, D’Oré, 1850. Prod. Paléont., p. 299.
ACTHONELLA MINIMA, Bronn. 1848. Index Paleont., p. 13.

C. Testa subcylindricd, vel ovata; spird depressd, inversd; apice mammillato; anfractibus
numerosis, marginibus rotundatis; anfractu ultimo, subconvexo, basi contracto.

Shell subcylindrical, ovate, or bullzform; spire depressed, inversed; apex mam-
millated ; whorls numerous, with rounded margins; the last whorl somewhat convex, with
a contracted base.

This form is much shorter than the last, and less flattened; the apex of the spire does
not rise higher than the margin of the last whorl; it is mammillated, and consists of three
minute volutions; the vertex is moderately large and crateriform. This species is very rare,
and has only been observed in the “ planking.”

Locality. Minchinhampton Common. Aubenton, France.

Cy.inpRites prrirormis. Plate VIII, figs. 20, 20a, 4,c; 21.

C. Testé cylindro-pyriformi, cava apiciali contracté profundd, margine acuto elevato;
apertura ad basim vie dilatata, plicis magnis.

Shell cylindrical or pyriform; the apicial cavity contracted and deeply excavated,
having an acute and somewhat elevated margin; aperture linear; the folds on the
columella large.

This shell is more pyriform than its congeners, the anterior extremity being short but
attenuated, and the apicial cavity deep and contracted. The cast (fig. 21) has not the
produced acute margin to the cavity exhibited by the shell (fig. 20), the cavity consequently
appears smaller; the apex of the spire is large but deeply situated.

Axis 7 lines, greatest transverse diameter 43 lines, diameter of the cavity 1} lines.

Locality. The planking of Minchinhampton Common. Casts of this shell occur higher
in the series in shelly hard sandstone one mile east of Minchinhampton ; in both positions
it is rare.

Acrzontna, D’ Orbigny, 1850.

CocHLiTEs cYLINDROIDES, Luid. 1760,

AcT£oN, sp., Phillips. ActTmon, sp., Sow.

Urricutus? Brown. 1845. Elements of Fossil Conch.
_ Brown. 1849. Illustrations of Fossil Conch.

GASTEROPODA. 103

C. Testa ovato-oblongd; spird sub-elatd; anfractu ultimo magno, elongato; apertura
longitudinaliter anfractui ultimo nonnunquam pari, superne angustatd, inferné latiori; labris
continuis, tenuissimis, labio interno non reflecto.

Shell ovately oblong; spire rather elevated; the last whorl large and elongated ;
aperture sometimes as long as the last whorl, narrow in its posterior, wider in its anterior
part ; lips continuous and very thin, the inner lip not reflected upon the columella.

The genus Utriculus was established by Capt. Brown, upon the recent Bulla obtusa,
and was afterwards used to comprise certain species of recent and fossil shells, previously
referred by authors to Bulla, Acteon, &c.* Although the general form of the shells thus
classed together is somewhat similar, this character cannot always be considered as
definite, asmuch as the animal inhabitant of the fossil species may have materially differed
from the recent type. Alc. d’Orbigny, in recognising the generic differences of some allied
forms, described as Zornatella, subsequently proposed in the ‘ Prodrome de Paléontologie,’
the name Acteonina for their reception. ‘The genus Orthostoma, instituted by Deshayes,
includes an allied series of shells, and connecting them with Acteon and Cylindrites, if we
may judge from the figures given in the ‘'Traité Elementaire de Conchyliologie,’ but of
which no description has yet been published. Upon the ground, therefore, of the doubtful
generic identity of the recent Bulla obtusa with our fossil shells, we have preferred to adopt
the name proposed by D’Orbigny.

ACTH£ONINA OLIV£FoRMIS, Dunker. sp. Plate VIII, fig. 14.

Buta oLIvmrormMis, Koch and Dunker. 1837. Nordd. Oolith., t. v, fig. 3.
ACTEONINA — D’Orb. 1850. Prod. Paléont., p. 353.

A. Testa ovato-cylindraced, levi ; spird productiusculd, acutd ; anfractibus spird sub-
convexis ; apertura superné angustata.

Shell ovately cylindrical, smooth; spire rather small, or but little produced ; whorls
rather convex; the upper part of the aperture narrow.

Locality. Three examples only, varying much in size, are in our collection. They
occurred in the soft shelly stone (termed ovenstone) which overlies the weatherstones at
Minchinhampton Common. It is a thinly-laminated deposit, which is sometimes nearly
made up of the valves of Ostrea acuminata ; when these are absent, their place is occupied
by a multitude of small bivalves; or, when these again become scarce, other and more
interesting forms occur, among which may be ranked the present species.

1 With regard to the comparative generic differences of the family Bullide, the reader is referred to an
interesting paper by Mr. Clark, published in the ‘ Annals of Natural History,’ for August 1850, from which
it appears, by a careful study of the structure of the animals, that the generic subdivisions established by
some authors in this group are not well characterised.

104 MOLLUSCA FROM THE GREAT OOLITE.

ACTHONINA? PARVULA, Roemer, sp. Plate V, figs. 11, lla, 12.

BuccinuM PARVULUM, Roemer, 1836. Nordd. Oolith., p. 139, t. xi, fig. 23.
ACTEONINA PARVULA, D’Oré. 1850. Prod. Paléont., p. 353.

A. Testé parvd, ovato-conicd ; anfractibus (4) subconvexis superioribus, lateribus sub-
planis ; apertura integra elongatd, bast angustatd, columella contortd.

Shell small, ovately conical; whorls (4) rather convex upon their upper portions, but
flattened upon their sides; aperture entire, elongated; base narrow; columella twisted.

This little shell varies much in the length of the spire, specimens with narrow whorls
having a greater degree of convexity at their upper part than the others, but in all of them
the spire is shorter than the last volution. The largest specimens have an axis of 4 lines,
and a transverse diameter of nearly 3 lines.

Locality. Minchinhampton. It is found not unfrequently in all the quarries of the
district, and is common to the shelly beds.

AcT#HONINA? BULIMOIDES. Plate VIII, fig. 15.

A. Testé ovato-elongatd, levi; spird elaté obtusd ; anfractibus (3—4) subconvevis,
anfractu ultimo subcylindrico ; apertura ovata ; labro sinistro incrassato.

Shell ovately elongated, smooth, with an obtuse elevated spire; whorls (3—4) some-
what convex, the last whorl subcylindrical; aperture ovate; inner lip thickened but not
broad.

The general figure is pupzform; the aperture in length does not exceed half that of
the entire shell.

This species has been provisionally arranged under <Acteonina, although the great
thickness of the shell and expanded columellar lip do not well agree with that genus, and
rather approximate it with Bulimus. In general form it is very near to the Chemnitzia
Cornelia, D’Orb., ‘Terr. Jurass,’ t. 245, figs. 2, 3, from the Coral Rag of France ; and
both species may hereafter be found to belong to a genus distinct from Chemnitzia and
Acteonina.

Locality. Minchinhampton. ‘I'he specimen figured is the only example which has
come to our knowledge. The exact bed from which it was obtained is rather doubtful ;
but, judging from the matrix to which it is attached, we should infer that its position was
probably the upper portion of the Great Oolite.

GASTEROPODA. 105

ADDENDA.

AMMONITES GRACILIS, Buckman. Plate XIII, figs. 2, 2a; and Plate I, fig. 3.

The description of this species is given at page 12, but the additional figure is here
given (Plate XIII, fig. 1,) to illustrate the form and general character of the more mature
shell, which differs considerably from the young state of it. (Plate I, fig. 3.)

It has the general form of Am. Charmassei, D’Orb.; but the costa in J. gracilis are
not interrupted over the back as in that species, and the volutions are more fully exposed.

Preroceras Wricutu. Plate XIII, fig. 1.

P. Testa fusiform, tumidd ; anfractibus (6) rotundatis, levibus vel spiraliter striatis ;
ultimo gibbo, transversim carinato ; carinis tribus rotundatis inequaliter remotis ; in digitos
longiores productis ; dorso ad angulum tuberculis duabus magnis ; labro quinque? digito,
digitis in etate adultd longissimis, flexuosis, recurvatis ; caudd longissind arcuatd.

Sheil fusiform, volutions 6, rounded and smooth, or faintly striated; the body-whorl
inflated, and having three indistinct carinz developed on its upper surface, two of which
have a transverse prominent tubercle ; each carina leads to a digitate process; labial wing
short, and terminating in four long slender flexuous digitations ; the first digitation ascends
close to the spire, and is attached to it; it curves a little outwards, and then extends back-
wards an inch and a quarter beyond the apex of the spire, where it is broken off;! the
second curves gently outwards and backwards; the third is broken off three quarters of an
inch from the labial wing; a remaining fragment indicates that it curved gently outwards,
and is represented by a dotted line in the figure; the fourth passes forwards for an inch
and a half, and then curves outwards; the canal is long, and arched backwards.

This fine fossil presents some points of resemblance to Strombus Oceani and 8. Ponti,
Al. Brongniart, but the latter species has upwards of six carinee upon the last whorl. In size
it exceeds all the other Great Oolite examples of the Stroméide, and would seem to be very
rare. One specimen in the cabinet of the author, which has not the wing developed, and is
in other respects imperfect, is the only other known example. The present remarkable shell
is in the cabinet of Dr. Wright of Cheltenham, who has kindly communicated it, and to

1 There are traces of another digitation between the first and second above described, arising near to
the base of the former, but apparently broken off in the specimen figured.

106 MOLLUSCA FROM THE GREAT OOLITE.

whom it is dedicated. The cast of a shell figured by Goldfuss, t. 173, fig. 3, under the
name of Buccinum antiquorum, from the dolomitic Oolite of Bavaria, may possibly belong
to an allied species of the same genus.

Locality. Minchinhampton Common, in the beds of planking.

Neritopsis varicosa. Plate XI, figs. 20, 20a; Plate XIII, fig. 5.

N. Testé neritiformi, ovato-oblongd, varicibus magnis longitudinalibus (circd 10 in
ambitu), plus minusve elatis, et lineis numerosis, transversis, regularibus, elatis decussatis ;
lineis cum striis densissimis perpendicularibus tnstructis.

Shell neritiform, ovately oblong; varices large, longitudinal (about 10 in a volution),
more or less elevated, decussated with numerous regular, elevated, and transverse lines ;
the lines are impressed with extremely fine and dense perpendicular striz; the aperture
round.

A very thick ovate shell; the varices vary much in magnitude, so that m some
specimens they are nearly obsolete, but the large encircling lines are always conspicuous ;
the dense striations upon the lines are only visible under a magnifier.

Locality. Minchinhampton Common, where it is rare; but it occurs not unfrequently
in the middle division of the Inferior Oolite.

Trocuus sprratus, D’Archiac. Plate XIII, figs. 6, 6a. Plate X, figs. 2, 2a, 2d.

TRocHUS sPIRATUS, Archiac. 1843. Mém. Soe. Géol. de France, tom. v, p. 378, t. 29
fig. 4a—e.
_ — Bronn. 1848. Index Paleont., p. 1306.
—_ — D Orb, 1850. Prod. Paléont., p. 300.

T. Testé conicd, apice acuto, anfractibus (4A—5) lateribus planis, subtér medio sub-
angulatis, cingulis et lineis ornatis ; cingulis duobus, primo prope suturam approximato,
secundo majori, acuto, parte inferiore anfractuum sito ; lineis inter cingulos striis longitudi-
nalibus impressis; basi levi subconvead, umbitlico nullo.

Shell conical, apex acute, whorls 5, their sides flattened, somewhat angulated
beneath their middle portions, and encircled with bands and lines; the bands are two in
number; the first is wide, flattened, and placed close to the suture; the second is pro-
minent, acute, forming a slight angle, and placed near to the base of the whorls; between
the bands are several rather obscure encircling lines, which are indented by longitudinal
stri ; base smooth, slightly convex ; no umbilicus.

The variation in the prominence of the bands, of the lines, and of the general state of
preservation, occasions considerable diversity in the aspect of this species, and requires

ANNELIDES. 107

several examples for its elucidation. The figures given at Plate X, figs. 2, 2a, 24, do not
exhibit the degree of angularity in the whorls and prominence in the bands which is
usually seen, and the longitudinal indentations are more than usually prominent The fine
encircling striz, although not shown in the specimen figured by M. D’Archiac, are par-
ticularly mentioned in the description of the species. The axial and basal diameters are
nearly equal.

Locality. It is tolerably abundant in the Minchinhampton district, occurring in all
shelly beds. Eparcy, France.

CLASS—ANNELIDES, Cuvier.

SERPULA OBLIQUE-STRIATA. Plate V, fig. 19, 192.

L. Testé vermiformi, lateribus subcompressis, striis crebris irreqularibus, obliquis antice
curvatis, in cristam longitudinalem flectis.

Shell vermiform, the sides slightly compressed, with striz closely arranged, irregular,
oblique, curved towards the anterior extremity, and bent into a longitudinal ridge.

Locality. It is rare, and occurs in the planking of Minchinhampton Common. Of the
few specimens seen, none exceed an inch in length, and 2 lines in their transverse diameter.

Note on the term ‘‘ PLANKING.”

It will be observed that the term “planking” is frequently used in stating the position and range of
fossils from Minchinhampton Common. ‘This is a name applied indifferently by quarrymen to any stone,
the beds of which divide into thin horizontal slabs or planks. At Minchinhampton Common it is understood
to indicate the uppermost of that series of shelly beds which are known as the weatherstones, or stones which
are supposed to be capable of resisting the disintegrating action of frost. At Bussage and Eastcombs the
term white stone is employed by quarrymen when speaking of this bed, which at the two latter localities
has quite changed its mineral character. It is not improbable that this white stone is the English repre-
sentative of the pierre blanche of the Great Oolite of Normandy, which has yielded to M. Deslongchamps so
numerous a series of shells.

THE MOLLUSCA

OF

THE “GREAT OOLITE OF YORKSHIRE.”

Ciass—CrErPHALOPODA.!

BeLemnites eicanteus, Schloth. Plate XIV, figs. 4, 4a.

BELEMNITES GIGANTEUS, Schloth. 1813. Min. Taschenb., vii, p. 70.
— — Schloth. 1820. Petref., p. 45, No. 1.
— ELLIPTICUS, Miller. 1823. Geol. Trans., 2d Series, ii, pl. 8, figs. 14—16.

2 — — Blainville. 1827. Mem. Belemn., p. 102.
if — GLADIUS, Blainville. 1827. Mém. Belemn., p. 86, pl. 2, fig. 10.
2 — CoMPRESSUS, Sow. 1828. Min. Con., t. 590, fig. 4.

— AALENSIS, Voltz. 1830. Meém., p. 60, pl. iv, fig. 7.
— — Zieten. 1830. Pet. Wurtemb., pl. 19, fig. 1.
— GRANDIS, Zieten. 1830. Pet. Wurtemb., pl. 20, fig. 1.
2 — comprEssvs, Phil. 1835. Geol. of Yorksh., vol. i, pl. 9, fig. 38.
— AaLEensIs, Phil. 1835. Geol. of Yorksh., vol. i, p. 124.
— GIGANTEUS, Quenstedt. 1843. Flézg. Wurtemb., p. 329.
_ — D Orb. Ter. Jurrass., pl. 14, fig. 15.
— — D’ Orb. Prod. Paléont., p. 261.

B. Testé elongatd, compressd, crassd, acuminata vel subinflatd, posticé acuminata,
lateraliter sulcatd, anticé dilatatd ; apertura subovah. Alwveolo angulo, 20—25°. (D’Orb.)

1 The following species of Mollusca are chiefly figured from the collection of Mr. Bean, and the
localities are given upon the authority of that gentleman. They include all the species of univalves
enumerated by Professor Phillips as occurring in the ‘Gray Limestone or Oolite of Cloughton, Brandsby,
and Cave’’ (‘Geol. of Yorkshire,’ vol. i, p. 123, &c.); and most of the specimens illustrated in this
Monograph appear to have been obtained from the Yorkshire coast. We have previously assigned our
reason for keeping the fossils of this locality distinct from those of the West of England, and shall merely
introduce the following general remarks by Prof. Phillips as bearing upon the subject. ‘‘ The distribution
of the organic remains in the ‘road-stone,’ or slaty rock of Brandsby, Cave Oolite, and Inferior Oolite sand,
has yet been carefully ascertained at only a few points; and the following observations will probably here-

CEPHALOPODA. 109

The guard is more or less elongated and compressed, sometimes conical and acumi-
nated towards the extremity; at other times contracted near the apex, and enlarged rather
suddenly towards the alveolus; the furrows, with which the extremity is marked, vary in
different specimens, both in their number, depth, and size; there are generally two on the
dorsal part, one being prolonged much more than the other. The angle of the alveolar
cavity varies, according to M. D’Orbigny, from 20 to 25°, and is inclined towards the
ventral side. The aperture is generally of an oval form.

This is a very variable species, and has consequently been described under a great
variety of names. M. D’Orbigny, after carefully studying a large number of specimens
obtained from many localities, infers that the variety of form assumed by this species is
mainly to be attributed to sexual differences.

This species is generally considered to be characteristic of the Inferior Oolite in
England, Germany, and France; but we have not been enabled to detect any specific
difference between the specimens forwarded by Mr. Bean, from the Bath Oolite of
Yorkshire, under the names of B. Aalensis, B. compressus, and typical specimens of the
B. giganteus, obtained from the Brown Jurassic formation of Wurtemberg.

Locality. The Gray Oolite near Scarborough. Inferior Oolite of the west and south
of England.'

AMMONITES MACROCEPHALUS, Schloth. Plate XIV, fig. 2.

AMMONITES MACROCEPHALUS, Schloth. 1813. Min. Taschenb., vii, p. 70.
— — Schloth. 1820. Petref., p. 70, No. 16.
— — Zieten. 1830. Pet. Wurtemberg, t. v, figs. 1, 4, 7;
t. xiv, fig. 3.
— — Quenstedt. 1843. Flézg. Wiirtemb., p. 363.
— — D Orb. Ter. Jurrass., p. 430, pl. 151.
— — D’Orb. Prod. Paléont., p. 297.
a TEREBRATUS, Phil, 1835. Geol. of Yorksh., vol. i, p. 116.

after receive several corrections. At present it appears to me that the ‘road-stone’ is characterised by the
great abundance of Gervillia acuta and Crassina minima, and by the presence of Pholadomya acuticostata,
Rostellaria composita, and the genus Acteon. Where this rock is united with the Middle Oolite, as at
White Nab, these fossils commonly lie near the top; where it is entirely deficient (as at Ewe Nab), they
are scarcely to be found. The top of the Cave Oolite (as under Gristhorpe Cliffs, at Ewe Nab, Owlston,
and Ellerker) is generally marked by abundance of Millepora staminea, and plates and spines of Lchini,
and columnar joints of Pentacrinus caput Meduse. In the substance of the rock occur Belemnites, Isocardia,
Pholadomya, Cucullee,Perne, Pinne, Plagiostome, Pectines, and Terebratule. So large a proportion of
its organic contents occurs likewise in the Inferior Oolite sand beneath, that it is difficult to point out what
seem to be characteristic.”

1 We have had the opportunity of examining some fine specimens of this species in the collections of
Mr. Bowerbank and Mr. Baber.

15

110 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

A. Testé discoided, subinflatd ; anfractibus involutis subcompressis, rotundatis, lateribus
26—30 costatis ; costis subrotundatis, obtusis, in medio laterum bi vel trifurcatis continuts ;
apertura semilunari, umbilico angustato.

A discoidal, somewhat inflated, shell, with rather subcompressed volutions, and a narrow
and deep umbilicus ; margin of the umbilicus with 26 to 30 obtusely-rounded ribs, which
subdivide into two or three smaller ones in passing over the back; aperture semilunar,
deeply impressed by the previous volution.

Locality, Near Scarborough.

Ammonites Buacprnt, Sow. Plate XIV, fig. 3a, 6.

AMMONITES BLAGDENI, Sow. 1813. Min. Con., pl. 201.
— coronatus, Schloth. 1813. (Not Am. coronatus, Brug., 1789.)
-—— _ Zieten. 1830. Pet. Wurtemb., t. i, fig. 1.
— Biacpent, Phil. 1835. Geol. of Yorksh., vol. i, p. 124.
— CORONATUS, Quenstedt. 1843. Floz. Wiirtemb., p. 326.
— BiacpeENI, D’Oré. Ter. Jurrass., p. 396, t. 132.

A, Testé discoided, subcylindricd, late umbilicatd ; anfractibus subdepressis, lateribus
dechivibus, costatis ; costis 20—28 ewterné tuberculatis, subacutis ; dorso subconvexo, trans-
versim costato ; apertura transversd, quadrangulari.

A discoidal, thick, and widely-umbilicated shell, formed of rather depressed quadran-
gular yolutions, ornamented with 20 to 28 obtuse costa, terminating in spiniform tubercles
on the outer margin, and from each of which arise 3 to 5 smaller costz, which pass over
the back ; the aperture is transverse and quadrangular.

In some specimens the tubercles are sharper, differently formed, and more numerous
than in others.

In the shell figured, which measures about six inches diameter, there are 17 marginal
ribs ; in another specimen from the same locality (Scarborough), about one foot in diameter,
the number is 28. The numerical proportion of these coste, however, do not always
icrease or decrease with regularity during the progress of growth. There are two
specimens of 4m. coronatus, Zieten, in the British Museum, which are certainly identical
with our shell, im one of which the inner volution has 25, and the outer 27, marginal cost,
showing an increase; in the other specimen, the inner whorl has 21, and the outer only
17 coste, showing a decrease in their number. ‘The specimen figured by M. D’Orbigny
has only 15 tubercular coste surrounding the umbilicus.

Locality. Near Scarborough ; Inferior Oolite, Somerset ; Bayeux, &., France ; Brown,
Jura 6, Stuiffen, Wurtemberg. (Quenstedt.)

GASTEROPODA. 111

Ammonites BRAIKENRIDGII, Sow. Plate XIV, fig. 1.

AMMONITES TRIPTOLEMUS, Bean. MS.
? — BRAIKENRIDGII, Sow. 1813. Min. Con., t. 184.
— _ D Orb. Ter. Jurrass., t. 135, figs. 2, 3.

A. Testé discoided, anfractibus (5—6) expositis, subrotundatis, costatis ; costis (30—36)
externé tuberculatis, in medio laterum bifidis, subinde trifidis, continuis ; dorso subconvexo ;
apertura transversd, subdepressd, eaterné angulata.

A discoidal shell, with 5—6 exposed, somewhat rounded and costated volutions; with
30—36 marginal cost, tuberculated externally, from each of which arise, about the
middle of the side, 2 and sometimes 3, rather obtuse smaller ribs, passing over the back ;
aperture wider than high, somewhat convex, with angular sides.

This Ammonite (forwarded to us with the name, 4. 7riptolemus), belonging to the
section Coronari, appears to be intermediate to 4. Humphriesianus and A. Braikenridgit,
with the latter of which it is the more closely allied, but differmg from it by the smaller
coste (in the cast) not being wholly enveloped by the later volutions. We regard the
specimen figured as only the adult state of this species.

Locality. Near Scarborough.

CLASS—GASTEROPODA.

AvariA Parisi, D’ Ord. sp. Plate III, fig. 5; and Plate XV, figs. 15, 15a.

? RosTELLARIA HAMUS, var. 3, Deslongchamps. 1842. Mem. Soc. Linn. de Normandie,
tom, vii, p. 174, t. 9, fig. 36.

(See description, antea page 18.)

We have provisionally retained (page 18) M. D’Orbigny’s specific name for the
Yorkshire shell, believing that the one figured as Rostellaria composita, by Phillips, pre-
sented certain differences from that described in the ‘Min. Conch.,’ occurring in the
Oxford Clay of Weymouth. But Mr. Sowerby distinctly states that he has received the
same species from near Scarborough, so that the differences may prove, when a larger
number of specimens shall have been examined, to be due merely to variations arising
from local conditions. The Yorkshire shell appears to be identical with Rostellaria hamus,
var. 3, of M. Deslongchamps, cited above, from the Great Oolite of Ranville.

Locality. Near Scarborough. ‘This species is also found in the Inferior Oolite of
Yorkshire, and in the same formation at Dundry and Bridport.

112 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

CrritHium Branu. Plate XV, fig. 5.

C. Testé parva, turritd, apice obtuso, anfractibus numerosis angustis, subplanis, 5
costatis ; costis tuberculosis, tuberculis circa 16 in ambitu; costis inequalibus ; suturis
anfractibus profundé depressis.

Shell small, turreted; apex obtuse; volutions numerous, narrow, rather flattened, ©
encircled with five rows of costa; costae tuberculated, the tubercles being about 16 in a
volution ; ribs unequal; the sutures of the whorls deeply depressed.

The third and fifth row of cost are less prominent than the others, the tubercles are
large and prominent, the length of a volution is less than half its transverse diameter, the
first two volutions are nearly smooth. Length 5 lines, transverse diameter 2 lines.

Locality. Near Scarborough. i

Natica appucta. Plate XV, figs. 17, 17a.

Natica appvucta, Phillips. 1835. Geol. of York., vol. i, t. 9. fig. 30.
— — Williamson. Geol. Trans., 2d Series, vol. v, p. 241.
—_ _ D’Orb. 1850. Prod. Paléont., p. 264.

NV. Testa globosd, spird elatd, anfractibus (4) converis, superné rotundatis, suturis
depressis, anfractu ultimo obliquo ; apertura ellipticd, umbilico obtecto.

Shell globose, spire elevated and pointed, whorls (4) convex, with depressed sutures,
their upper portions rounded ; the last whorl oblique; aperture large, elliptical ; inner lip
with a covered umbilicus.

Natica grandis, Goldfuss, is our only Great Oolite species which approaches near to
this form; but that shell, though greatly expanded, has not more volutions than the present
species, a fact which militates greatly against their identity. Length 9 lines, breadth
8 lines.

Locality. Great Oolite near Scarborough. The original specimen figured by Phillips.

Natica punctuRA. Plate XV, figs. 18, 18a.

LiTTorINa PUNCTURA, Bean. 1839. Mag. Nat. Hist., p. 62, fig. 23.
— — Morris. 1843. Cat. Brit. Foss., p. 149.

NV. Testé ovato-ventricosd, spird elatd, acutd ; anfractibus (6) convexiusculis, suturis
profunde impressis; anfractu ultimo magno, punctato et cingulato; punctis minutis, in

GASTEROPODA. 113

hineis transversis sed irregularibus instructis, et lineis tenuissimis longitudinalibus trans-
versisque decussatis ; apertura ovata, labro externo tenui.

Shell ovately ventricose, spire elevated and pointed, whorls (6) rather convex, with deep
sutures ; the last whorl large, oblique, its surface punctated and cingulated ; punctz minute,
disposed in close but irregular arranged transverse lines; they are decussated by numerous
very fine lines, both longitudinal and transverse ; the entire surface of the whorl is likewise
divided into several (4 or 5) encircling zones by as many lines, which are prominent,
rendering the spaces between them rather flattened ; aperture ovate, outer lip thin, inner
lip rather flattened and excavated. Axis 11 lines, transverse diameter 8 lines.

The following is Mr. Bean’s original notice of this species :

“Shell turbinated, finely striated longitudinally and transversely, which, under a high
magnifier, gives it a very beautiful appearance ; whorls (6) rounded and well divided, the
body whorl occupying one half the length of the shell. Aperture elliptical, pillar lip thick
and a little flattened, outer lip very thin; length nearly ? inch, breadth } inch. The only
specimen procured from the Cornbrash; but in the Inferior Oolite at Peak Hill it is not
uncommon. ‘The specimens found there are larger, coarser, and the spire is not so much
produced.”

Locality. Bath Oolite near Scarborough. In the collection of Mr. Morris.

Natica ? (EUSPIRA) cIncTA. Plate XV, fig. 20.

PHASIANELLA cInoTA, Phillips. 1835. Geol. of York., vol, i, t. 9, fig. 29.
— — Williamson. Geol. Trans., 2d Series, vol. v, p. 241.
_— — D Orb. 1850. Prod. Paléont., p. 267.

NV. Testdé ovati, spird elata, anfractibus (4) latis, superné carinatis, suturis canaliculatis ;
anfractu ultimo, bicarinato ; aperturd ampld, suborbiculari.

Shell ovate, spire elevated, whorls (4) broad, their upper portion with an obtuse
encircling carina; the sutures channelled; the last volution, with an obtuse carina,
occupying very nearly the middle of the volution ; aperture large and suborbicular.

The specimen placed at our disposal, by the kindness of Mr. Bean, is the original one
figured by Professor Phillips. It is rather compressed, which gives an appearance of
greater breadth to the shell than it possessed; the perfect form would approach our
Eh. pyramidata, from which it is distinguished by the second carina, which is not less
strongly marked than the upper one. Length 15 lines, breadth (uncompressed)
103 lines.

Locality. Great Oolite near Scarborough.

114 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

Nerita psEupo-costaTa. Plate XV, figs. 3, 3a.

Nerita costata, Phillips. 1835. Geol. of York., vol. i, t. 11, fig. 32.
— — Morris. 1843. Catalogue, p. 154.
— psnupo-costaTa, D’Orb. 1850. Prod. Paléont., p. 264.

NV. Testé parva, subhemispherica ; spiré pared, depressé; costis longitudinalibus,
regularibus rotundatis et levibus.

Shell small, subhemispherical ; spire small and depressed ; ribs longitudinal, numerous,
regular, rounded, and smooth.

This shell appears to be identical with the well-known Inferior Oolite species.
Occasionally there is some little irregularity about the cost, and they are not always so
prominent as in the Yorkshire example. Size that of a moderate-sized pea.

Locality. Near Scarborough ; also in the Inferior Oolite of Yorkshire. (PAzi/ips.)

Evia tayieata, Plate XV, fig. 4.

LE. Testé subulato-turritaé, apice acuto ; anfractibus (11) subconvexis, obsolete costatis ;
anfractu ultimo symmetrico.

Shell subulate, turreted; apex acute; whorls (11) very slightly convex, smooth, or
with slightly-marked costz ; the last whorl symmetrical.

This little shell is very subulate, the length of the whorls being nearly equal to their
transverse diameter. This character, and the degree of convexity, separates it from a shell
very abundant in the Great Oolite at Minchinhampton, which we have described under the
title of Hulima communis. In that species the volutions are fewer, and the shell is more
pyramidal. Length 7 lines.

Locality. Near Scarborough.

CHEMNITZIA ? veTUSTA. Plate XV, fig. 7.

TEREBRA vETUSTA, Phillips. 1835. Geol. of York., vol. i, t. 9, fig. 27.
— — Williamson. Geol. Trans., 2d Series, vol. vy, p. 241.
CuEeMNitzia — D'Orb. 1850. Prod. Paléont., p. 263.

C. Testa elongata, turritd ; anfractibus (9) subconvevis, longitudinaliter costatis ; suturis
depressis ; costis circa 12, rotundatis levigatis curvatis.

Shell turreted, volutions (9) rather convex, and longitudinally costated ; ribs, about 12
in a volution, rounded and smooth, bent from left to right; the sutures of the volutions
deeply impressed.

GASTEROPODA. 115

The figure is lengthened, almost subulate, the convexity of the volutions being but
slight ; their transverse diameter exceeds their length by about one third. Longitudinal
dimensions 5 lines, transverse diameter 2 lines.

Locality. Near Scarborough.

CERITHIUM GEMMATUM. Plate XV, fig. 6.

C. Testé parva, turritd ; anfractibus convexiusculis, nodulis cingillatisque 5 ; nodulis
ovatis subdistantibus, circa 24 in ambitu.

Shell small, turreted ; volutions rather convex, encircled with five rows of nodules ;
nodules ovate, about 24 in a volution ; the rows of nodules are slightly curved, and the
last volution has from 7 to 9 rows.

The little nodules are regular, oval, their longer diameter being in the axis of the shell,
and they are distant from each other about their own diameter; the number of volutions
are but few, apparently not more than 7. Length 7 lines, transverse diameter 2 lines.

Locality. Great Oolite near Scarborough.

Cuemnitzia ? ScarBurcensis. Plate XV, fig. 8.

C. Testé magna, pyranidato-turritd, levi ; anfractibus subplanis ad suturas subplicatis,
aut vittd latiusculd transversd, plus minusve convexd notatis ; aperturd ovata, superneé
strictissimd ; columellé marginatd, supra subcallosd. ?

Shell large, pyramidal, turreted, smooth; whorls nearly flat, but with one fold near to
their sutures, or with a broad transverse band more or less convex ; aperture ovate, very
narrow above; columella marginated, thickened above.

The upper border of the whorls is slightly turned, their junctions are strongly defined.
The longitudinal diameter of the penultimate whorl is 7 lines, the transverse diameter
10 lines.

Locality. The specimen forwarded to us by Mr. Bean is from the dark-gray shale of
the Great Oolite near Scarborough. It is only a cast, and much compressed, so that the
specific character cannot be sufficiently determined.

Trocuus Lecxrensi. Plate XV, figs. 21, 21a.

T. Testd conico-depressd, anfractibus (4A—5) planis, costulis rotundatis crebris cinetis ;

116 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

costulis transverse dense-striatis ; basi subconverd densé costulatdé et concentricé striata ;
umbilico nullo.

Shell conical, but depressed ; whorls (4—5) flattened, encircled with closely-arranged,
nearly equal rounded ribs; the ribs are densely striated longitudinally ; the base is rather
convex, having very closely-arranged costa, crossed by concentric striz ; no umbilicus.

The junctions of the whorls are rather obscurely marked, and the lower margin of the
last whorl is angulated. The little ribs upon the base are very delicate and fine; the outer
lip is imperfect, and does not enable us to describe the aperture; but there is nothing
visible upon the surface of the whorls which would indicate that it belongs to Plewrotomaria.
The height is two thirds of the basal diameter.

Locality. Scarborough. In Mr. Leckenby’s cabinet.

Trocuus moniuitectus, PA. Plate XV, figs. 1, la.

Trocuus MONILITECTUS, Phil. 1835. Geol. of York., vol. 1, t. 9, fig. 33.
— — . D Orb. Prod. Paléont., p. 265.

T. Testaé conicd, anfractibus (8) planis, suturis obscuris 4—5 costatis ; costis crebris
oblique crenulatis.

Shell conical, volutions (8) flattened, with indistinct sutures, and encircled with 4—5
rows of costz ; the coste are closely arranged, and crenated obliquely.

The costa are large, the crenations closely arranged, and pass obliquely from left to
right. Length 43 lines, basal diameter 33 lines.

Locality. Near Scarborough. ‘The original specimen figured by Phillips.

Turso rLaBoratus, Bean. Plate XV, fig. 2, 2a; and Plate IX, figs. 27, var.

TURBO ELABORATUS, Lycett. 1850. An. Nat. Hist., vol. vi, p. 416, pl. 11, fig. 1.

T. Testé subturritd, apice acuto, anfractibus (4) subconvewis, superné planis, inferneé
costulis longitudinalibus numerosis, aliis transversis decussantibus ; anfractu ultimo ventricoso
obliquo, apertura ovata.

Shell turreted, apex acute, whorls (4) convex, their upper borders flattened horizontally,
their sides and lower portions, with numerous longitudinal ribs, transversely decussated
by others; last whorl oblique; aperture entire, ovate. :

The longitudinal ribs are rendered nodulous by those which are transverse ; the latter
are 4 or 5 in number; the last volution has numerous encircling ribs, but the longitudinal
ones do not extend beyond the middle of the volution; and when more than four whorls
have been completed, the last whorl is destitute of longitudinal ribs, but in lieu of them are

GASTEROPODA. 117

very fine densely-arranged longitudinal lines. The latter features are not exhibited by the
specimen from Scarborough; but one, of more advanced growth, from the Inferior Oolite
near Minchinhampton, is much larger and more satisfactory. The upper portions of the
whorls are flattened, smooth, and even a little sulcated; the inner lip is thin; the base is
rounded, so that it neither exhibits the thickened lip of Zcttorina, nor the basal produced
form of Zurbo. Length of the Scarborough specimen 5 lines, transverse diameter of the
last whorl 4 lines.
Locality. Great Oolite near Scarborough.

Turso Puituirsi. Plate XV, figs. 12, 12a, 6.

T. Testé trochiformi, cingillatdque costatdé ; costis striato-nodulosis ; striis indentis ;
striis longitudinalibus numerosissimis ; anfractibus planis ; aperturdé subrotundd, basi effusd,
vel productiori.

Shell trochiform, encircled with numerous ribs ; ribs striated and nodulous ;_ striz
longitudinal, very numerous, indenting the ribs; volutions flattened; aperture rounded ;
its base effuse, or produced anteriorly.

Two ribs, more prominent than the rest occupy the middle of the last whorl, and give
it rather an angulated figure; the pointed extremity of the base removes it from the
Iittorine. Longer diameter 9 lines, transverse diameter 7 limes.

Named in compliment to the author of the ‘ Geology of Yorkshire.’

Locality. Great Oolite near Scarborough.

PHASIANELLA LATIUSCULA. Plate XV, fig. 16.

P. Testé ovatd, spird acutd, elatd; anfractibus (6) latis, convexiusculis ; anfractu
ultimo subventricoso.

Shell ovate, spire acute, elevated; whorls (6) broad, convex, the last whorl rather
inflated.

This may be considered as a form connecting our P. elegans and P. tumidula ; the
spire is much more elevated than in the latter species, and the whorls are wider than in the
former. ‘These remarks, however, are made with the reservation which must be exercised
in describing casts, for the specimen figured is in that condition. The length is 1 inch,
the transverse diameter 7 lines.

Locality. Near Scarborough.

16

118 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

PHASIANELLA sTRIATA, Sow. Plate XV, fig. 19.

MELANIA STRIATA, Sow. 1814. Min. Con., tab. 47.

PHASIANELLA sTRIATA, Sow. Min. Con., 1834. Index, p. 5.

TEREBRA —_ Lonsdale. Geol. Trans., 2d Series, vol. iii, p. 275.
— Morris. 1843. Cat. Brit. Foss., p. 163.

MELANIA — Roemer. 1836. Nordd. Oolith., p. 158, t. 10, fig. 1.
— — Goldf. 1844. Petref., p. 112, t. 198, fig. 12.

PHASIANELLA — JD’Orb. 1850. Prod. Paléont., p. 333.

P. Testé turritd, ventricosd ; anfractibus (1) subconvewis et striatis ; striis (15) trans-
versis ; basi profunde striata ; aperturd depressd, suborbiculari ; columella excavatd. '

Shell turreted, ventricose ; whorls (7) somewhat convex and striated; strie but faintly
impressed, and about 15 in number upon each whorl; the base deeply striated ; aperture
depressed, nearly circular ; columella excavated.

The figure is subpyramidal, the length of the whorls being rather more than half their
transverse diameter ; the sutures of the whorls are deeply marked, the base of the last
whorl is deeply grooved ; the base of the aperture is very wide, and the transverse diameter
of the aperture is nearly equal to the longitudinal. The length of the entire shell is about
3 inches, the transverse diameter through the last whorl is 21 lines.

Locality. Great Oolite near Scarborough. In the middle and west of England this
species occurs in the upper beds of the Inferior Oolite and Coral Rag.

Act#won, Montfort. 1810.

TORNATELLA, Lam.

Shell ovate, volutions few, transversely striated; spire obtuse; aperture narrow,
lengthened, entire; columella spirally thickened at its junction with the inner lip; outer lip
thin, smooth.

Actmon Srpevici, Phil. sp. Plate XV, figs. 9, 9a.

AuricuLa Sepevici, Phil. 1835. Geol. of York., vol. i, t. 11, fig. 33.
— — Williamson. Geol. Trans., 2d Series, vol. v, p. 241.
— _— Bronn. 1848. Index Paleont., p. 136.

ACTEON _ D’ Orb. 1850. Prod. Paléont., p. 263.

A. Testa parva, ellipticd, transversim striato punctatd ; striis crebris, punctis impressis ;
spird subconica, gradata ; anfractibus subplanis, ultimo inflatu ; apertura elongato- elliptica,
angustata,

GASTEROPODA. 119

Shell small, elliptical, transversely striated, the strize numerous and punctated ; the spire
conical, step-like ; the whorls rather convex, the last inflated; the aperture is an elongated
ellipse, narrow above and beneath.

The Yorkshire specimen, placed at our disposal by Mr. Bean, is much compressed
and imperfect, and has the spire somewhat less elevated than the following species, which
resembles one figured by M. Deslongchamps from the Inferior Oolite of Les Moutiers,
near Bayeux. ‘The species has not been found in the middle or west of England.
Longitudinal diameter 5 lines, transverse 3 lines.

Locality. Great Oolite near Scarborough.

Actzon putius. Plate XV, fig. 11.

? ToRNATELLA PULLA, Koch. 1837. Nordd. Oolith., p. 33, t. 2, fig. 11.
22 _ PULCHELLA, Deslongchamps. 1848. Mem. Soc. Linn. de Normandie, viii,
pl. 18, figs. 4a, 4b. (striis remotis.)

A. Testé ovata, spird elatd, subacuté ; anfractibus (6) convexiusculis, striis transversis
numerosis regularibus et punctatis ; anfractu ultimo subcylindrico ; apertura ovata.

Shell ovate, spire elevated, somewhat acute; whorls (6) convex, the last whorl sub-
cylindrical ; aperture ovate; the surface with numerous regular punctated encircling strie.

As compared with 4. Sedgvici, of which it may prove to be only a variety, this is much
more elongated, the length of the aperture but very slightly exceeding half of the entire
length of the shell; the volutions are convex, and of moderate breadth; the base is
rounded, but narrow. Length 33 lines, transverse diameter 2 lines.

Locality. Great Oolite of Scarborough. It has not been found in the middle or west
‘of England.

Actzonina, D’ Orbigny.

AcTHONINA GIGANTEA, Desi. sp. Plate XV, fig. 13.

TORNATELLA GIGANTEA, Deslongchamps. 1842. Mém. Soe. Lin. de Normandie, vol. vii,
pl. 10, figs. 27, 28.
Actronrna Destonecuampstt, D’Orb. 1850. Prod. Paléont., p. 299.

A. Testdé ovato-turritd, spird elatd, apice acuto; anfractibus subplanis, superné rotun-
datis ; aperturd angustd, basi dilatatd ; columella ad basin marginata.

Shell ovate, turreted; spire elevated, acute; whorls rather flattened at their sides, but
rounded above; aperture narrow above, dilated below ; columella marginated at its base.

The specimen forwarded to us from Yorkshire is only a cast, but there is no doubt of

120 MOLLUSCA OF THE GREAT OOLITE OF YORKSHIRE.

its identity with the Normandy species, which is from the Great Oolite of Ranville. It
likewise occurs in the upper beds of the Inferior Oolite near Minchinhampton. Length
21 lines, breadth 10 lines; the aperture is about three fifths of the entire length of
the shell.

Locality. Bath Oolite near Scarborough.

Actmontina GLABRA, Phil. sp. Plate XV, fig. 10.

ACTEON GLABER, Phil. 1835. Geol. of York., vol. i, t. 9, fig. 31.

— — Williamson. Geol. Trans., 2d Series, vol. v, p. 241.
UtricuLus — Brown. Ill. Foss. Con., p..101, t. 47, fig. 30.
ACTEONINA GLABRA, D’Ord. 1850. Prod. Paléont., p. 264.

A. Testa subcylindricd, apice obtuso, spird parva ; anfractibus (5) angustis, subconvewis ;
anfractu ultimo cylindrico ; aperturd angusta, basi effusd.

Shell subcylindrical, apex obtuse, spire small, whorls (5) narrow, rather convex ; last
volution cylindrical; aperture rounded, and expanded beneath.

The spire is very blunt and depressed, the volutions being very narrow, and without the
slightest angularity. Length 8 lines, transverse diameter 4 lines.

Locality. Great Oolite near Scarborough. In Gloucestershire it is only found in the
Inferior Oolite.

Acr#onina TumIpuLA. Plate XV, fig. 14.

A. Testé parva, spird easertiusculd ; anfractibus angustis, rotundatis, suturis depressis ;
anfractu ultimo subcylindrico ; apertura elongato-ovata.

Shell small, spire depressed, volutions very narrow, rounded, their sutures deeply
depressed ; the last whorl gibbous ; aperture an elongated oval.

This species is shorter than any other of the genus with which we are acquainted. The
figure of the last whorl is only moderately cylindrical ; and the transverse diameter of this
portion is not much less than the entire length of the shell. Length 45 lines, transverse
diameter 33 lines.

Locality. Near Scarborough.

ANNELLIDA.

VermicuLaria NoDus, Phil. Plate XIV, figs. 8a, 4.
VeRMICULARIA NoDUS, Phil. 1835. Geol. of York., vol. i, p. 124, t. 9, fig. 34.

V. Testé levi, in spiram turbinatem convolutd, anfractibus (3) conveaiusculis ; anfractu
ultimo ad basin convexo, et lined obsoletd submesd cincto.
Shell smooth, forming an obtuse turbinated spire, with three volutions, which are

GASTEROPODA. 121

rather convex ; the last whorl rounded towards the base, with an obscure encircling line
placed a little beneath the middle of the whorl; aperture not exposed.
Locality. Scarborough, Westow, and Whitwell; also in the Cornbrash. (Pdillips.)

SERPULA PLICATILIS, Goldf. Plate XIV, figs. 5a, 3, ¢.

SERPULA PLICATILIS, Goldfuss. 1833. Petref., p. 229, t. 68, fig. 2.

S. Testa laxd vel curvatd, lateribus subconvewvis, leviusculis, costulis arcuatis per paria
approzimatis ; carind continud rectd. (Goldf.)

Shell loose or unwound, irregularly curved, slender, rather convex, smooth; the sides
have little, obscure, closely-arranged, curved coste, not visible upon the majority of
specimens ; the dorsal carina is simple, continuous, but not much elevated or conspicuous.

This minute species was gregareous, a considerable number being clustered upon a
small Pecten.

Locality. Scarborough.

SERPULA stLcaTa, Sow. Plate XIV, fig. 6.

SERPULA suLcaTA, Sow. 1829. Mun. Con., t. 608, figs. 1, 2.

S. Testd sublaxd aut curvatd, levi, subcarinatd ; carind dorsali levigatd ; sulcisque
angustis carine approximatis ; lateribus subplanis.

Shell partially unrolled, curved, smooth; dorsal carina smooth, with a narrow sulcus
on each side of it; sides of the shell rather flattened ; lines of growth visible upon different
portions of the surface.

The mode of growth in this species appears to have been very irregular. In its young
state it was flattened at the sides, but subsequently became much more rounded ; and the
figure of the aperture is nearly orbicular.

Locality. Scarborough. Inferior Oolite near Stroud.

SERPULA INTESTINALIS, Phil. Plate XIV, fig. 7.

SERPULA INTESTINALIS, Phil. 1835. Geol. of York., vol. i, p. 110, t. 5, fig. 21.

S. Testd sublaxd, levi, compressiusculd, sulco leviter depresso, superné et inferné sita.

Shell smooth, partially unrolled, somewhat compressed above and beneath with a slight
longitudinal sulcus in the middle of the two flattened sides.

This species is destitute of a carina, nor are any lines of growth visible; the sulcations
are only to be seen upon the unrolled portion of the shell.

Locality. Bath Oolite, Scarborough ; also in Oxford Clay and Cornbrash. (Phzlhips.)

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LIST OF

AUTHORITIES REFERRED TO IN THIS WORK.

Arcuiac, V. dD’. 1845. Description Géologique du Département de |’Aisne. Mem. Soc. Geol. France,
tome v. 4to, Paris.
Buarnvitie, D. pe. 1827. Mémoire sur les Belemnites. 4to, Paris.
Bronn, H. G. 1836. Uebersicht und Abbildungen der bis jetz bekannten Nerinea-arten, Neues Jahrbuch,
1836, p. 544.
— 1835—38. Lethza Geognostica. 2 vols. 8vo, and Atlas 4to, Stuttgard.
— 1849. Index Paleeontologicus. 3 vols. 8vo, Stuttgard.
Brown, Capt. T, 1834—49. [Illustrations of the Fossil Conchology of Great Britain and_ Ireland.
4to, London.
Buvienipr, M. A. 1843. Sur quelques Fossiles nouveaux, &c. Mem. Soc. Philomath., Verdun.
2 vols. 8vo.
ConYBEARE and Pui.uips. 1816. Outlines of the Geology of England and Wales. 8vo, London.
Desuayess, G. P. 1835—45. Lamarck’s Hist. Nat. des Anim. sans Vertebres. 3d Edition.
— 1840—50. -Traite Elémentaire de Conchyliologie, &c. 8vo, Paris.
DrsLonecuamps, EB. 1842—48. Mémoires de la Société Linnéenne de Normandie. Vols. 7 and 8,
Ato, Caen.
Dr Haan. 1825. Monographie Ammoniteorum et Goniatiteorum Specimen, &c. 4to, Leyden.
D’Orzieny, AucipE. 1848—50. Paléontologie Francaise, Terrains Jurassiques. 8vo.
— 1850. Prodrome de Paléontologie Stratigraphique. 1st vol., 8vo, Paris.
Firron, Dr. W. H. On the Stonesfield Slate. Zool. Journal, vol. iii.
FieminG, Rey. Dr. J. 1828. History of British Animals. 8vo, Edinburgh.
Gotpruss, A. 1826—44. Petrefacta Germaniz. 3 vols. fol., Dusseldorf.
Ispetson and Morris. 1847. Notice of the Geology of the Neighbourhood of Stamford and Peterborough.
Report Brit. Association. 8vo, London.
Kocu and Dunxer. 1837. Beitriage zur Kenntniss des Norddeutschen Oolithgebildes und dessen Versteine-
rungen. 4to, Brunswick.
Luwyp, E, 1760. Lithophylacii Britannici Ichnographia. 8vo, Oxford.
LonspaLE, W. 1832. On the Oolitic District of Bath. Trans. Geol. Soc. London. Vol. iii, pt. 2.
Lycrrt, J. 1848. On the Fossil Conchology of the Oolitic Formations in the vicinity of Minchinhampton,
Gloucestershire. Annals and Mag. Nat. Hist., 2d Series, vol. ii, p. 248.
— 1847. On the Mineral Character and Fossil Mollusca of the Great Oolite. Geol. Proc., 1847,
p. 181.

124 AUTHORITIES REFERRED TO IN THIS WORK.

Marcou, J. 1848. Recherches Géologiques sur le Jura Salinois. Mém. Soc. Géol. France, 2% Série,
vol. iii.

Morris and Lycerr. 1850. On Pachyrisma. Quart. Journ. Geol. Soc., vol. vi, p. 399.

Puruiirs, J. 1835. Illustrations of the Geology of Yorkshire. Part I, 4to, London.

QuenstepT, F. A. 1843. Das Flozgebirge Wiirtembergs. 8vo, Tubingen.

Reinecksn, C.M. 1818. Maris protogaei Nautilos et Argonautas, vulgo Cornua Ammonis, in agro Coburgico
et vicino reperiundos descripsit et delineavit, &e. Dr. J. C. M. Rernecker, cum Tabulis XIII,
col. Coburgi, 8vo.

Roemer, F. A. 1836. Die Versteinerungen des Norddeutschen Oolithengebirges. 4to, Hanover.

Scuatotuem, EB. F. 1813. Minéral Taschenbuch. S8vo, Frankfurt.

— 1820—22. Die Petrefaktenkunde. 2 vols. 8vo, Gotha.

Sowrrsy, G. B. 1823. Genera of Recent and Fossil Shells. &vo.

Sownrsy, Jamus, and J. pp C., 1812—29. Mineral Conchology of Great Britain. 6 vols. 8vo, London.

SrRICKLAND and Buckman. 1845. Maurchison’s Geology of Cheltenham. 2d Edition, 8vo, London.

Vourz, P. L. 1830. Observations sur les Belemnites. 4to, Paris.

— 1836. Ueber das Fossile genus Nerinea. Neues Jahrbuch, 1836, p. 538.

Wixtiamson, W. C. 1837. On the Distribution of Fossil Remains on the Yorkshire Coast, from the
Lower Lias to the Bath Oolite inclusive. Trans. Geol. Soc. London. 2d Series, vol. v, pt. 1.

Youne, G. and Birp, J. 1828. A Geological Survey of the Yorkshire Coast. 2d Edition, 4to. Whitby.

Die Versteinerungen Wiirtembergs. Folio, Stuttgardt.

Enea Se ae Te Petrefactions de Wirtemburg.

CORRIGENDA.

Page 1. Line 18, for Hailsworth read Nailsworth. Page 49. Chemnitzia Lonsdalii, Plate VIII, read Plate VII.
» 2. In foot-note, line 6, for Nuns read Nunnery. » 62. Trochus squamiger, Plate X, figs. 2, 2a, 2, read
» 3. Line 26, after Gresslya, erase the word or, and Plate IX, figs. 34, 34a.

place a,,. » 86. Line 26, for with, read fo.
on 4. Line 33, for Pterocera read Alaria, » 96. Line 24, for Loliolum read doliolum.
» 8and9. The two Belemnites occur also at Minchin- » 99. Line 8, after “remaining species,’ read to the

hampton. species of section B.
» 16. To the last line add, wing simple, undivided.

INDEX

OF

SPECIES RETAINED IN THIS WORK.

[I. O., ov C-b., afived, shows that the species also occurs in the Inferior Oolite, or Cornbrash.|

Page Plate
ACTHONINA
bulinoides WD eb seats sis UB
oliveeformis NOS e Oy hay 4
? parvula NOE oo G5 tm A UIE
ALARIA
armata Oras is ge
atractoides LO cos aro Ae
cirrus PDN cs Gey tty NOt, MSY
hamulus V7 3 son ind, G0.
hamus Mog ey rian
hexagona LAs aries |
leevigata Vier: dy taids OG:
pagoda EGrc ante Ors bo, teed
paradoxa VAD) Seeey tins WD a wlenbinedis
3 (var)? “20%.” 3,1. 9a.
parvula OF EP8 £12, 1ST
Phillipsii 1S) 5 Gh 1 Oy 5s AIO):
trifida Dias be lan Ose. O-b.
AMMONITES
arbustigerus WGA es oP a ek aloe -
gracilis POO SS Weta. diy loske 25) (Gs
macrocephalus 12.. 2, f. 3, a.
subcontractus We pal aptanlise lias
a Jun. f. 2, 2a.
Waterhousei G3 SRllssied ce MUO
BELEMNITES
Bessinus Sopa lets), 7:
‘fusiformis Sina ll, 1.6, 8:
BRACHYTREMA
Buvignieri 24, YES; £.4,
turbiniformis 2) He 9) f. 85a
Buia
doliolum OGr pO nLG; @ O-
undulata Oey Be suter 8 tshy OF

CERITELLA
acuta
conica
gibbosa
longiscata
mitralis
planata
Sowerbii
rissoides

unilineata
CERITHIUM
limeeforme
pentagonum
Roissii
sexcostatum
strangulatum
quadricinctum
Tennantii
CHEMNITZIA
Hamptonensis
Leckenbyi
Lonsdalei
phasianoides
simplex
Wetherellii
variabilis

CYLINDRITES
acutus
altus
angulatus
brevis
bullatus
cuspidatus
eylindricus
excavatus

Vg

Page Plate
37 22 05 LoL /, Os te kOe
39 unos te lO amomes
SO os keully.
40..9, £.14.
Det O ELD:
38) Os bal, LA:
Bis) Hiatt L(y
Arc Dike se
Ore Os talons, Late
eM rere Gy is Me
SOF. Oi ty 228
BP cucaify te Mel Gy
30 75) tas Ge
Ole Oates
Dae) cs iss\b)s 3 te bore
SD Dt paae
50! Wen /5: fe UG:
00.07, £..48
AO Te fake Los as
Dillee OS te ae
49:07, £. 15.
DOE NM 75) 1-105 Oe
51 O08, £.7,.a, 1
98) Sy ta Gans

Oe:
102.

100.
100.

#8, £. 12) anes
-e8, £11) ates
FO, falas

#8; f. 118, a; Gypet
8, £..10f@:

*8, £19, ebpie
#8; £..17, Annee:

126

Page

INDEX.

Plate

CyLINDRITES (continued).

pyriformis
Thorenti
DELPHINULA
alta
Buckmani
coronata

102..
WOU. 0105 be aly BOC:

8, f. 18, a, 5, ¢.

Ales Op fo od.
(ACP
70, + 9,4.28,

(Sub-genus) CrossosToma.

? discoideum
? heliciforme
Prattii

DESLONGCHAMPSIA
Eugenei
EMARGINULA
scalaris
EvuLtm™a
communis
pygmeza
subglobosa
vagans
EUSPIRA
canaliculata
coronata
pyramidata
Sharpei
subcanaliculata

FISSURELLA
acuta

Fusus
coronatus
multicostatus
subnodulosus,

Monoponta
decussata
formosa
imbricata
Labadyei
Lyell

NatIca
ambigua
formosa
globosa
grandis
intermedia
Michelini
neritoidea

79 v0 Wj ba fg Os
(feioo Wine te, LAO).
Foi Wileieols 1,0;

B4 . 6 1208. 13,4,
B39. 6, ta ya, c= T:O)

AS Te Oe derail Cs
AST re Osiks Us
A995 £10.

A Siero tetas 4:
a5. 211; £.23, a: 1-0,
AG 6 5 Oh 1D

AG Os dst Os ice

AG ewewl Uapta 2oe

AU 5 (Osi Sis

85... 8, f.5, a—e.

De. he We itu
D3 ge, tebsiG,
oad, £.9,5 a
68:11, £9, ia.

65 11 £. 6, a, B,

he 5 seer:

6S. fall,.t. 23 Netotoll, a.

OFaew lil, teva re ele,
Ay walO5 ih.)

AD eetO5 be lO

AD evo, a. 14

Al S46, t.12.

Alva0. t. laa

44.. 6, f.2, 2a; £.3; 3a.
Ad Ag Ostet

Page Plate
Natica (continued).
Stricklandi ne Abb fig PLS
Tancredi AD eo Ost allie
Verneuili AAT is 0; £510,105 ta fends
NAvTILUs
Baberi 10 sank tt. 1, a.
dispansus Dy ity bay fe
subtruncatus NO ew tals, as
NERIN@DA
Dufrenoyi 34..7, f.8, a—e.
Eudesii SI su/splelOs ds lost el Os
funiculus HO) Bea 7/5 185 WA Aa
punctata eae tis U5 oy
Stricklandi BBY oc hein
Voltziu O2) ssaudy ts Vl ws Mars tess as
and 13; i211.
NERITA
cancellata Olmos lil tol obides
costulata Dome Oa) bs Oy RENO 5
Wi veihes Aas KO)
rugosa SOM lilewteul 7anes
(Sub-genus) Nertpomus.
hemispheerica Noh gg eM Ge ee 7
minuta DSvemoplulet Osu. LO:
(Sub-genus) Neriropsis.
striata Ms 6 IIS eR Sy oe
sulcosa Ole apt l 2 oaeleOs
varicosa 1065.11; f. 20) a;
UB sa, UNO)
PaGcopus
sub-genus AMBERLEYA.
nodosa HN. 6 Hh US, UROP
PATELLA
arachnoidea OP Sig UI i Oar
Aubentonensis 91.. 12, f. 7,.a, 6, ¢, d.
cingulata SB ae Lait a5) ea ee
inornata OS cele, Lala LEO:
nana OS erli2sete LOS ae
Roemeri OW pee dl2, sf. 10. aaOe
rugosa 89)... 12,.£. 1,.d2=7orho:
paradoxa OOM, 12; f. 29a:
striatula ON. Later eaeos
sulcata 90 pel 2S fa 3 ee
suprajurensis 92 alos EpOvee:
PHASIANELLA
acutiuscula Haye HWA 1m Ashen
conica Heke op Wie oe BX

Page Plate

PHASIANELLA (continued).

elegans The 3 oA tis Orig

nuciformis ave eta nig Plt

Leymeriei We ge Wigs Bile Gh CVE

parvula Wome lly £:0 2001

tumidula AO ps lllly cio Pier
PILEOLUS

leevis HO) ooh ts BY, Chay IOS

plicatus 60 .. 9, f. 36, a, 6, ec. 1.0.
PLEUROTOMARTA

clathrata 79ers LON. 6510:

composita BO WO, fy 15,00;

discoidea (isi oo UD; ti Ue

obesa 7s LOS te Tl,

pagodus Gia olOsb 9,

scalaris Hi oo NOssie Wel
PTEROCERAS

Bentleyi M5baeros te UDseae Vane ta Ge

ignobilis 14. .35,f. 14.

Wright 105\., . a5 hol
PURPUROIDEA

glabra Ps) 9 Aly ats By 5 ity Oy Oh

Moreausia PY 6 a Elo at Il, Gg th Sh Bye Zip

nodulata 28 Bits Mies Oy Syeel
RIMvULA (Cor. O.

Blotii 87.5 =. Gtwonaese. 1.0:

clathrata 86... Sadsliionea. 1:0:

tricarinata 86..8, f. 2, a—e. 1.0.
RISSOINA

acuta Don. 9 tO eulioaats. 9)

cancellata Be pny lke 7:

duplicata 52... 9, f., 10.

leevis DAnerey Ospte wOnneO:

obliquata 52 29,4. 195 1.0;

tricarinata NB gy Wha MS
SERPULA

oblique-striata 107..5, f. 19, a
SoLartuM

disculum AOn: ~ OFFA QD ay 6

polygonium 69..9, f. 24, a, 6

varicosum O9ls. 95 f.825;00 00
STOMATIA

Buvignieri 85"... 9). 32,4
TROCHOTOMA

acuminata S2iene LOM ea, 20:

conuloides 827. LOS Ek LG:

discoidea S45, Ost Osa, (0, c.

INDEX.

127

Page Plate
TROcHOTOMA (continued).
extensa 83... 10, f. 19a, 6
obtusa Sane LONt. Wand
tabulata SE) oo WO si WH/5
TRocHUS
anceus OS 6 6 Al 1 Hy Zh
Bunburii 63... 10, f I ab
Dunkeri es ae By WH
Ibbetsoni 620. LON tare
obsoletus } a eelltle Te oll,
pileolus 63:2 LOS fa onan e
plicatus Ole OSsterc sas
squamiger G2). Gh t S4e almost
spiratus 106; ; 10) tf. 2, a, 6.- and
By is (Oh 7
TURBO
capitaneus O65 Oh te oh OH IO
elaboratus 6452 9Sf275 LO
Gomondei GOno Wnt A,
Hamptonensis Oe 5 Oh tin GLU Gs 5 MOY
obtusus Hoo Wil, ie O a5 UO), a
pygmeeus 605. 9, f. 295.4
Sharpei 5 so Oh i eh
UMBRELLA
Hamptonensis NG o 1 iS Ie, Ge
YORKSHIRE SHELLS.
AcTZON
pullus Ory Loseta lel
Sedgvici 118i. 1551 9:
ACTMONINA
gigantea Di ag alae Ie LO).
glabra IPAS layne wile EO:
tumidula UPA) a ns re dle!
ALARIA
Phillipsii aon, toy, ALO)
AMMONITES
Blagdeni 110... 1454 3;/a) Ako!
Braikenridgii 111..14,f.1. I.0.
macrocephalus 109.. 14, f. 2.
BELEMNITES
giganteus 108:3.. 14; far FO:

128

CERITHIUM
Beanii
gemmatum
CHEMNITZIA
Scarburgensis
vetusta
EULIMA
leevigata
NATICA
adducta
cincta
punctura
NERITA
pseudocostata

AcTAON
acutus

cuspidatus

glaber
ACTHONINA

Deslongchampsia

Page

MILD aee
LUNG eer

INS Ge
114..

We
2 ieee
PLOT.
WA cr

114..

Eparcyensis

oliveeformis

AMMONITES

INDEX.

C-b., 1.0.

INDEX OF

Page

PHASIANELLA
latiuscula
striata

SERPULA
intestinalis
plicatilis
suleata

TRocHUS
Leckenbyi
monilitectus

TURBO
elaboratus

VERMICULARIA
nodus

0:

LO:

1.0.

Page Plate
Ws 5 Was 1 WG
ilfeyis SG tm IT
Pi cen 14, hee 7:

Lil es AA San
Loe Las 10).
Ws Dip CS ce
DGiee al omatoul are
NG UGS ie PO
NOL WE ve th

SYNONYMS.

BELEMNITES (continued.)
canaliculatus

compressus

arbustigerus
Blagdeni
Braikenridgii
coronatus

discus
gracilis

macrocephalus .
terebratus

Triptolemus

AURICULA
Sedgvici

BELEMNITES
Aalensis
Bessinus

ellipticus
fleuriausus
fusiformis
giganteus
gladius
grandis

Buccinum

parvulum

unilineatum

Bubba

elongata
oliveeformis
Thorentea
undulata

Cassis

Eparcyensis

CERITHIUM

Blainvillii
Defrancii
Dufrenoyi

CERITHIUM (continued).
limeeforme
pentagonum
strangulatum

quadricinctum .

CHEMNITZIA
Roissii
vetusta

DELPHINULA
coronata
stellata

DITREMARIA
acuminata
conuloides

EMARGINULA
Blotii
clathrata
Goldfussii
scalaris
tricarinata

EvUOMPHALUS
coronatus

FISSURELLA
acuta

Fusus
nodulosus
subnodulosus

HELcION

Aubentonensis .

cingulata
nana
rugosa
sulcata

LITTORINA
punctura
MELANIA
striata
Monoponta
leevigata
Lyellii
Murpx
nodulatus
tuberosus
Natica
adducta
globosa

. 114

INDEX.

Page

30
30
31
29

32

70
70

82
82

87
86
86
88
86

70

85

23
23

91
88
93
89
90

IY

Slice)

68
57

28
28

5 Wily

43

NATICA (continued).
grandis
Michelini
Verneuili

NERIN.EA
cylindrica
Defrancii
funiculosa
punctata
Voltzii

NERITA
costata
costulata
hemispheerica
mais .
minuta
ovata
pseudocostata
pulla
sulcosa

NERITOPSIS
sulcosa
varicosa

PATELLA
ancyloides

Aubentonensis .

cingulata
costatula
mamillaris
nana
papyracea
rugosa
sulcata
suprajurensis
Tessonii
PATELLARIA
sima .

PHASIANELLA
cincta
Leymeriei
striata

PILEOLUS
leevis
plicatus

PLEUROTOMA
longiscata
rissoides

5 le!

5 alte

129
Page

41
44
44

36
33
36
35
32

. 114

97
58
58
58
58

58
59

59

. 106

89
91
88
60
60
93
60
61
90
92
89

61

5 Me

74

60

60

40
40

130

PLEUROTOMARIA
clathrata
obesa
pagodus
scalaris

PURPURA
Lapierrea
Moreausia

PuRPURINA
Moreausia
unilineata

PTEROCERAS
atractoides
cirrus
hamulus
hamus
paradoxa
Phillipsii

RIMULA
acuta
clathrata

RISsoA
acuta
duplicata
leevis
obliquata

RIssoIna.
acuta
duplicata
obliquata

ROSTELLARIA
bicarinata
bispinosa
cirrus
composita
hamulus
hamus
trifida

SERPULA
intestinalis

INDEX.

Page

79
79
77
V7.

28
27

27
38

19
22
17
16
20
18

85
86

53
02
54
92

53
52
52

21
21
22
18
7
16
21

» 221

SERPULA (continued).

oblique-striata .

plicatilis
sulcata
S1PpHo
clathrata
SoLaRIUM
coronatum
polygonum
TEREBRA
nodosa
striata
vetusta
TORNATELLA
cuspidata
gigantea
pulchella
pulla
TROCHOTOMA
acuminata
conuloides
TROCHUS
anceus
discoideus
Labadyei
monilitectus
obsoletus
plicatus
spiratus
TURBO
capitaneus
Deslongchampsi
elaboratus
Labadyei
Lyellii
obtusus
subobtusus
TURRITELLA
Roissil
UrricuLus
glaber

» 219
~ 19
Sy

. 116

LG

Page

> £07
a AI
5 ilPA

86

70
69

55

silts:
. 114

98

82
82

63
84
68

63
61

. 106

65
68

68
67
66
66
32

120

a a ee, ro. |
- =
> ae 7
AY; ‘ t:
- P 1
at A yo
o el
7“
i
*
ary
e I i
pa. .
ay
4
a /- ay
mes elle ike &
_ y + 7 =
. re ? el 7 : iy
: WON Shh te “4 ; veh OS iia “SPAS =
: ee
sWOIN aia 7

3 £4

wal obit 01 a eles! s
Viaty duo
anh kt att COL Ae Mice < ys vA ty galas ead ai

vy. rey nba (Bt 9 WoanOmion iy)

rm : nem

‘Lal , ae rade 0 Ys :

7 ee ~

es va an ie iale
7 : F Ae at Rete ey A ; i fe ise

7 \
nee) =
ne, Srionadtgnilg Ups Boerne 5
ee AN REAL tA taadeh 40a
?
A.
mas i :
(Oia? 1 ¢
1? 3 O

PLATE I.
Fig.
1. Nautilus Baberi, p. 10, side view.
la — — front view.
2. Nautilus subtruncatus, p. 10, side view.
2a. — — front view.
3. Ammonites gracilis, v.12, young; and p. 105, Plate XIII, figs. 2, 2a, adult.
Ammonites Waterhousei, p. 13, side view.
Aa. — — front view.
5. Belemnites Bessinus, p. 8.
ie — —~ showing the phragmacone.

6, 8. Belemnites fusiformis, p. 8.

PTE re mt a A APPT ASAE 218 PT

jst ASIAN eat aa rise

Ya Now: Size

Ya Nor: Sine.

Trinted by Hullmandel & Walton

ily

WHBa

big ‘ : j wal
van ee | bel ol
Ve aiins nn

wae ee Gil) a
a. t. Me tehy By ae Sates UY ea
# diy Vy : nt a hak? . } a a Ass ; py ‘i

i : yi 7h) yi
Ly no J f Pag: ‘ le ; iy. . ; ley Le S (se
} vi ‘ i ; F *1 oT A : y » ig aay:
{ : ‘ i Pigs rr OS of VAN ns
a A ’ 7¥ fe
- » ag
as 7

TUS Foe ait
‘ft ee ee

j
i J
| ® 2
‘ ss.
tr a -
a ¥ f
: 1 7 j
ru4
; =

)
-
7
iJ = ;
rf
7 - .
7 ¥
i
i
oo a
.
}
i
f

PLATE II.
Fig.
1. Ammonites subcontractus, py. 11, side view.
la. — _ front view.
2,2a. — — young of.
3. Ammonites macrocephalus, var., py. 12, side view.
3a. -— front view.
4. Ammonites arbustigerus, p. 12, side view.
Aa. a — front view.
5. Nautilus dispansus, pz. 9, side view.

Da. _ — front view.

GPR Bone Printed by Hullmandel & Walton

rr

-—3~

——

~

Ate

PLATE III.

Fig.

1, la, c. Alaria armata, p. 16, back view.

1d. — — front view ; d, portion magnified.
2. Alaria hamus, p. 16.
2a. —_- — portion magnified.

20. — — front view.

3, 3a. — Alaria leevigata, p. 17.
4,46. Alaria hamulus, p. 17, back view.

Aa. = — specimen magnified.
b. Alaria Philhipsu, y. 18; and p. 111, Plate XV, figs. 15, 15a.
5a. — —- portion magnified. °
6. Alaria pagoda, py. 18; and Plate XIII, figs. 4, 4a.
7, 7a. — Alaria atractoides, p. 19.
8. Alaria hexagona, p. 19.
9. Alaria paradoxa,-y. 20, front view; and Plate XIII, fig. 3.
9a. — — var. a, back view.
10. a — back view.
11,114. Alaria trifida, p. 21, front view.
lla. —_- — back view.
Ie: —_- — portion magnified.
12a. Alaria parvula, p. 22.
126. — — magnified.
13,13a@. Alaria cirrus, p. 22.
14. Pteroceras ignobilis, p. 14.
15. — Bentleyi, p. 15, front view.

= = back view.
16. — = var. of, back view.

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Fig.

1. Purpuroidea Moreausia, p. 27, front view.

la. — ~~ back view.

2. _ — back view, shell of advanced growth,
larger specimen.

3. — — young shell, front view.

3a. — — young shell, back view.

4. = = cast of the interior.

5. Purpuroidea glabra, py. 28, front view.
5a. -- — back view.
6. = _ young shell, front view.

6a. — — young shell, back view.

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PLATE V.

Purpuroidea nodulata, ». 28, front view.
— — back view.
Fs a another example.
—— — young shell, front view.
— — cast of the interior.
Fusus coronatus,.p. 23.
Fusus multicostatus, p. 23.
Fusus (Brachytrema) Buvignieri, p. 24.
Delphinula Buckmani, p. 71.
Fusus subnodulosus, p. 23.
a a portion enlarged.
Ceritella conica, p. 39, front view.
—— — back view.
at a= smaller example.
oo _— magnified twice.
Actzeonina parvula, py. 104, front view.
= — back view.
— — younger example.
= — adult, magnified twice.
Ceritella unilineata, p. 38, and Plate XIII, fig. 8, Plate IX, fig. 15, var.
Ceritella planata, ». 38, natural size.
— — magnified three times.
Ceritella mitralis, p. 39.
Ceritella Sowerbi, p. 38.
Ceritella acuta, p. 37, young, front view.
— — young, back view.
= a adult, front view.
— — adult, back view.
Pagodus (Amberlya) nodosa, p. 55.

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PLATE VI.

Natica intermedia, p. 41, front view.
— — back view.

Natica Michelini, y. 44, front view, elongated variety.
— — back view, elongated variety.
— — another example, front view.
— — another example, back view.

Natica neritoidea, p. 43.

— ambigua, p. 44.

— Verneuili, p. 44, front view.

— — back view.

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— aa young shell, back view.

Natica (Euspira) pyramidata, p. 46, front view.

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Natica (Euspira) coronata, p. 46.

— formosa, p. 42.

— Tancredi, p. 42.

— grandis, p. 41.
Natica (Euspira) subcanaliculata, p. 47.
Natica globosa, p. 43.

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PLATE VII.

Fig.

ie Chemnitzia Hamptonensis, p. 50.

la. —_ — magnified.
2. Cerithium limeeforme, p. 30.

3. — sexcostatum, p. 30.

3a — — magnified.

A. Chemnitzia Leckenbyi, y. 50, magnified.

5. a Wetherellii, p. 50.

5a. — a magnified.

6. Nerina Eudesii, p. 33.

6a. — — magnified.

te Nerinza Voltzii, p. 32, young.

IG: — — section magnified.

8. Nerina Dufrenoyi, p. 34.

8a. — —_— magnified.

86. — a section magnified.
8c, 8e. — — p. 34, another variety.
8d. —_ — portion magnified.
9. Nerinza Stricklandi, p. 35

9a. — — portion magnified.
10, 10c. Nerinza punctata, p. 35.
10a. — — portion of external surface magnified.
104. — — section magnified.
ahs Nerina Voltzii, p. 32.
dita: <= — section.

12. Nerinzea funiculis, py. 36.
12a. — — portion of the surface magnified.
126. — — section magnified.
13. Chemnitzia Lonsdalei, p. 49, the young shell.
13a. _ —— the adult shell.
14. Cerithium Roissu, p. 32.
14a. - -— section of the shell.

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PLATE VIII.

Fig.
Te le. Rimula clathrata, p, 86.
16, le. — — magnified.
2, 2a. Rimula tricarinata, p. 86.
26, 2c. — — magnified.
3, 3a. Rimula Blotii, p. 87.
30, 3c. — — magnified.
A, 4a, 46. Emarginula sealaris, p. 88.
Ac. — — under surface magnified.
5, 5a. Fissurella acuta, p. 85.
54, de. — — specimen magnified.
6, 6a. Nerita costulata, p. 57.
64, c. — — specimen magnified.
(Paice Chemnitzia variabilis, p. 51.
76. — — magnified.
8, 8a. Bulla undulata, p. 96.
9, 96. Cylindrites acutus, p. 98.
9a. — — magnified.
10. Cylindrites cuspidatus, p. 98:
10a. — — magnified.
it, Ue, Cylindrites angulatus, p. 99.
114. == — magnified.
12, 12a. Cylindrites altus, p. 99.
126. - — magnified.
er Actzeonina ?
1S, 15a. Cylindrites brevis, p. 101.
130. —_ — magnified.
14. Actonina oliveeformis, py. 103.
15. Actzeonina bulimoides, p. 104.
16, 16a, 160. Bulla loholum, p. 96.
iia: Cylindrites excavatus, p. 100.
176. — — magnified section.
18, 186. Cylindrites bullatus, p. 102.
18a, 18c. —— oa magnified.
19, 192. Cylindritescylindricus, p. 100.
194, c. — — view of apex, and section of the same.
20, 204, 20c, 21. Cylindrites pyriformis, p. 102.
20a. — — magnified.
22, 226. Cylindrites Thorenti, py. 101.

22a, 22c. — -- magnified.

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29.

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30, 30a.
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33, 33a.
34,

34a.
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35a.
36, 36a.
36d.
36e.

37, 3/a.
376.

PLATE IX.

Eulima pygmea, p. 48.
Phasianella acutiuscula, p. 75, and Plate XI, fig. 28.
Eulima vagans, p. 48.
Chemnitzia phasianoides, p. 51.
Eulima subglobosa, p. 49.
Ceritella rissoides, p. 40.
Cerithium quadricinctum, p. 29.
Rissoina acuta, p. 53, and Plate XIII, fig. 9.
Rissoina duplicata, p. 52.
Rissoina cancellata, p. 53.
Rissoina tricarinata, p. 53.
Ceritella longiscata, p. 40.
Ceritella unilineata, ? from Ancliff, p. 38.
Rissoina? levis, p. 54.
Ceritella gibbosa, p. 37.
Cerithium strangulatum, p. 31.
— — showing the contracted aperture.
Rissoina obliquata, p. 52.
Cerithium Tennanti, p. 32.
Eulima communis, p. 48, front view.
— — back view.
Cerithium pentagonum, p. 30.
Solarium varicosum, p. 69.
— —_ view of the base.
— — surface magnified.
Solarium polygonium, p. 69.
Solarium disculum, p. 70.
Delphinula coronata, p. 70.
Turbo elaboratus, p. 64.
Turbo Sharpei, p. 65,
— — surface magnified.
Turbo pygmeea, p. 65.
— _— magnified view.
Turbo Hamptonensis, p. 64.
ae — magnified view.
Delphinula alta, p. 71.
Stomatia? Buvignieri, p. 85.
_— _— surface magnified.
Turbo capitaneus, p. 65.
Trochus squamiger, p. 62,* and Plate XIII, fig. 7.
— — back view.
Fusus (Brachytrema) turbiniformis, p. 25.
— —_ — front view.
Pileolus plicatus, p. 60.
_— — view of the base and aperture magnified.
— — side view magnified.
Pileolus levis, p. 60.
— — view of the base and aperture magnified.

* Incorrectly printed as Plate X, figs. 2, 2a, 6.

— <= tC

Printed by Hullmandel & Walron

PLATE X.

Fig.
1. Trochus Bunburyi, p. 63.
la — — magnified three times.
16 — — back view.
2. Trochus spiratus ? var., p. 106, and Plate XIII, fig. 6.
2a. — magnified.
26. — front view.
3. Trochus Dunkeri, p. 61.
3a. — — magnified.
4. Trochus Ibbetsoni, p. 62.
4a. — — magnified.
5. Trochus pileolus, p. 63.
ba. — — magnified.
5b. — — another example.
6. Pleurotomaria clathrata, p. 79.
6a. — — magnified three times.
7. Trochus anceus, p. 63.
fa. — — specimen magnified.
8. Trochus plicatus, p. 61.
8a. — — magnified.

9. Pleurotomaria pagodus, p. 77.
10. 'Trochotoma discoidea, p. 84, upper surface.

10a. — — magnified.
100. — — side view.
10e. — — costee magnified.

1]. Pleurotomaria obesa, pz. 79.

12. Pleurotomaria discoidea, p. 78.

13. Pleurotomaria composita, p. 80.

13a. — — portion magnified.
14. Pleurotomaria scalaris, p. 77,

15. 'Trochotoma obtusa, p. 83.

15a. — — front.

156. _- — back view.

16. Trochotoma conuloides, p. 82.

17. Trochotoma tabulata, p. 83.

17a. —— = front view.

18a. Trochotoma obtusa ?, p. 83, base.

186. —_ — surface magnified.
19a. Trochotoma extensa, p. 83.

194. — — back view.

20. ‘Trochotoma acuminata, p. 82.

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PLATE XI.

Trochus obsoletus, p. 63.
— _ magnified view.
Monodonta Labadyei, p. 68.
Monodonta imbricata, p. 67.
— _— magnified view.
Monodonta Lyellii, p. 67, front view.
— — back view.
— —_ the shell magnified.
Turbo Gomondei, p. 66.
Monodonta formosa, p. 68.
— “= magnified view.
Delphinula (Crossostoma) discoideum, p. 73.
oe = — magnified view.
Delphinula (Crossostoma) heliciforme, p. 73.
Turbo obtusus, var., p. 66.
— — magnified view.
Turbo obtusus, p. 66.

— — magnified view.

Monodonta Labadyei, p. 68.
Neritopsis sulcosa, p. 59.
Neritopsis striata, p. 59, front view.

= — back view.
Nerita hemispheerica, p. 58, front view.

— _ back view.
Nerita cancellata, p. 56, front view.

—~ _ back view.

_— — a portion of the surface magnified.
Nerita hemispheerica, p. 58, a smooth variety.
Nerita rugosa, p. 56.

Nerita costulata, p. 57.

— _ a portion magnified.
Nerita minuta, p. 58.

Neritopsis varicosa, p. 106, and Plate XIII, fig. 5.
Delphinula (Crossostoma) Prattii, p. 77.

—_— _ — an enlarged view.
Natica (Euspira) Sharpei, p. 46.
Natica (Euspira) canaliculata, p. 45.

- — _— back view.
Natica Stricklandi, p. 42.

_ — back view.

Phasianella tumidula, p. 76.
Phasianella nuciformis, p. 75.
Phasianella elegans, p. 74.
Phasianella acutiuscula, p. 75, and Plate IX, fig. 2.
Phasianella parvula, p. 795.
_ _ magnified view.
Phasianella conica, p. 74.
Phasianella Leymeriei, p. 74.
_ _ a globose variety.

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PLATE XII.

Fig.

1, 1a. Patella rugosa, ». 89, variety with large coste.

14. _— — magnified portion of the surface of figs. 1, La.
le, 1d. — — variety with fine coste.

le. _ — magnified portion of the surface of figs. lc, 1d.
Ly, lg: a — the young shell.

2. 2a. Patella paradoxa, p. 90.

26. — — magnified portion of the surface.

Bo, od. Patella sulcata, p. 90.

36. _- — magnified portion of the surface.

4, 4a, c,d. Patella cingulata, p. 88.

Ab. _ a magnified portion of the surface.

be Da: Patella striatula, p. 91.

5b. — — magnified portion of the surface.

6, 6a. Patella Roemeri, p. 91.

60. — — magnified portion of the surface.
Peta. Patella Aubentonensis, p. 91.

7b. — -— magnified portion of the surface.
06, “ha: -— — the young shell.

8, 8a. Patella arachnoidea, p. 92.

8d. —- — portion of the surface magnified.

9, 9a. Patella suprajurensis, p. 92.
10, 10a. Patella nana, p. 93.
11, lla. Patella inornata, p. 93.
12: Umbrella? Hamptonensis, p. 95.
12a. mo a the surface magnified three times.
13, 13a. Deslongchampsia Eugenei, p. 94, magnified twice.

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PLATE XIII.

Pteroceras Wrightui, py. 105. (In Dr. Wright’s collection.)
Ammonites gracilis, and Plate I, fig. 3, yp. 12 and 105.

— — front view. (In Prof. J. Buckman’s collection.)
Alaria paradoxa, and Plate III, figs. 9, 10, p. 20.
Alaria pagoda, and Plate III, fig. 18, p. 18.

— — magnified view.
Neritopsis varicosa, and Plate XT, fig. 20, p. 106.
Trochus spiratus, and Plate X, fig. 2, var., p. 106.
— — magnified view.
Trochus squamiger, and Plate IX, fig. 34, y. 62. Magnified view of a por-
tion of the surface.

Ceritella unilineata, and Plate V, fig. 13, p. 38.
Rissoina? acuta, and Plate IX, fig. 9, p. 53.
Nerinea Eudesu, and Plate VII, fig. 6, 7. 33. Section of interior.
Nerinea Voltzu, and Plate VII, fig. 11, y. 32. Section of interior.

PLATE XIV.
YORKSHIRE SHELLS.

Ammonites Braikenridgu, y. 111, reduced one half.
Ammonites macrocephalus, py. 109, reduced one half.
Ammonites Blagdeni, p. 110, side view.
— — front view, reduced one half.
Belemnites giganteus, p. 108.
— — transverse section.
Serpula plicatilis, p. 121.
= = magnified view.
— — transverse section.
Serpula sulcata, p. 121.
Serpula intestinalis, y. 121.

8a, 6. Vermicularia nodus, p. 120.

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PLATE XV.

YORKSHIRE SHELLS.

Fig
1. Trochus monilitectus, p. 116.
la. — — magnified view.
g. Turbo elaboratus, and Plate IX, fig. 27, p. 116.
2a. _ —— magnified view.
3. Nerita pseudocostata, p. 114.
3a. — -- magnified view.

4 Eulima levigata, p. 14.
5 Cerithium Beanui, p. 112.
6. Cerithium gemmatum, p. 115.
if Chemnitzia? vetusta, p. 114.*
8 Chemnitzia? Scarburgensis, p. 115.
9. Acteon Sedgvici, p. 118.
10. Acteonina glabra, p. 120.

Ls. Acteon pullus, p. 118.

12. Turbo Phillipsu, py. 117.

12a. — — back view.

126. — — surface magnified.

13. Acteonina gigantea, p. 119.

14. Actzonina tumidula, p. 120.

15. Alaria composita, var. Phillipsii, and Plate III, fig. 5, y. 111, and p. 18.
15a. a = magnified view.

16. Phasianella latiuscula, p. 117.

ie Natica adducta, p. 112, front view.

7a. oo back view.

18. Natica punctura, p. 112.

18a. == surface magnified.

19. Phasianella striata, p. 118.

20. Natica (Huspira) ? cincta, p. 113. |

21, 21a. Trochus? Leckenbyi, y. 115. (In Mr. Leckenby’s collection.)

* In this figure the costz near the suture are too much indented.

R Bone

Printed by Huimande

ra

PALHONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVII.

LONDON:

MDCCCLI.

Thi) Sa a Lee

A MONOGRAPH

ren: LSS el

OOLITIC AND LIASIC BRACHIOPODA.

BY

THOMAS DAVIDSON,

MEMBER OF THE GEOLOGICAL SOCIETY OF FRANCE,

PARI Pr

LONDON:
PRINTED FOR THE PALHONTOGRAPHICAL SOCIETY.

1851.

©. AND J. ADLARD, PRINTERS, BARTHOLOMEW CLOSE.

A MONOGRAPH

OF

BRITISH OOLITIC AND LIASIC BRACHIOPODA.

PRELIMINARY REMARKS.

Unper the lowest member of the cretaceous system, we discover an extensive series of
‘strata, consisting of different kinds of sands, sandstones, limestones, and clays, divided into
a number of groups, known to geologists under the name of Jurassic, or Oolite and Lias
Rocks. These form together a system of great thickness, traversing our island from the
Yorkshire Coast to that of Dorsetshire in the shape of a band, varying in breadth from a
few miles to between fifty and sixty in its midland course.

Great Britain is considered the typical country whence continental geologists obtained
the first clue to those divisions which, with differences only in the nature of their com-
position, have been traced over many parts of our globe.

The object of the present Monograph is not to enter into the Geology of this system,
which has been so ably illustrated by many celebrated British and Continental Geologists,
but an endeavour to trace the forms or species of Brachiopoda which lived at different
periods, while this vast amount of sediment was being deposited in the depths of the sea.

It may, however, be useful for the sake of reference, to give a tabular view of the
different members of the Oolite and Lias series. We cannot do better than extract it from
Mr. Tennant’s ‘ Stratigraphical List of British Fossils :’

acl oolitic shelly EE sometimes a Isle of Portland; Brill, &e.,
Patland Stone and’ Sand grained or compact, thick-bedded, and with

: Aylesbury, Bucks ; Thame,
layers of chert, and with subordinate beds of

Oxon; Tisbury, Wilts.
sand.
Kimmeridge, Dorsetshire ;
: : Dark blue and grayish laminated clay, with gyp- near Oxford; Stone and
dge Cl.
Bammernige Ulay sum and bituminous shale. Hartwell, Bucks; near
Swindon.

B

2 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Upper Calcareous Grit, {Coarse shelly limestones, more or less thick-

pees Oxon; West-
Coral Rag, bedded; coarse oolitic limestones abounding

brook, Calne, and Steeple
| Ashton, Wilts; Malton and

Lower Calcareous Grit . in corals, calcareo-siliceous grit. :
i 8 Scarboro’, Yorkshire.

Oxford Cl Dark blue clay, with Septaria; sometimes slaty) Chippenham and Wooton
Beis mS k and bituminous, with a subordinate band tf Basset, Wilts; Oxford;
<r aa ferruginous sandy limestone (Kel. rock). Yorkshire, &e.
Coarse rubbly limestone, thinly laminated with) Stanton, Malmsbury, Ash-
Cornbrash .
layers of clay. ford, Wilts.
: } ’ Corsham, Box, &c., Wilts;
Forest Marble Hts Bae pues shelly “imestone, sand, and Sapperton, Bradford, Ci-
gritstone, with layers of clay.
rencester.
df fi
Bradford Clay Layers of clay ; sometimes alternating with bands] Bradford, Burfield, Pickwick,
of limestone. Tetbury.

Great Oolite . .

ee : a
Ber shelly limestone, more or less compact an haiipton |/Gokanon en tae

Bath, Bradford, Minchin-
sandy, sometimes thick bedded. ;

fossiliferous).

" } ; ; (a) Cayton and Gristhorpe
n the Yorkshire Coast, the Great or Bath Oolite (4), (a hard, blue lime- Bays; (6) Clourtion and

stone ; fine-grained Oolite; hard blueish clay,) is contained between two White Nab; (c) between

thick beds (a, c) of gritty laminated sandstones and shales, containing an Cloughton Wyke and Blue

abundance of terrestrial plants. Wick.
Stonesfield, Oxon; Seven-
Stonesfield Slate. . . tm shelly, and gritty limestone ; slaty. hampton Common, &e

Bath, Box, near Stroud, and
Fullers-earth Clay H
ampton Common.

— layers of coarse shelly ragstone, with Fie |e Painswick, Brins-

Inferior Oolite vening bands of marland soft freestone. Fine- ¢ combe, The Cotteswolds,

Blue Wick, Yorkshire.
J cw Redcar, Yorkshire ;
Lower

grained sandstone and ironstone.

Alum shale; rubbly and sandy shales, &c.

Te Gloucestershire ; Somerset-

Lias limestone and shales. hire, Lyne Hema an

These names and divisions are in general use, though each continental country has, in
some cases, adopted synonymous denominations, which they always endeavour to attach to
the British original type.’

The latest innovation is published by M. D’Orbigny, in a small elementary work,
where he proposes the following classification :’

1 For ample information, consult the works of W. Smith, Conybeare and Phillips, Sir C. Lyell, Sir
H. De la Beche, Sir R. 1. Murchison, Professor Phillips, Morris, Webster, Buckland, Lonsdale, Buckman,
Young, and Bird, &c.; and the works of Elie de Beaumont, Dufresnoy, Baron Von Buch, Alcide D’Orbigny,
Bronn, Pusch, Roemer, D’Archiac, &c.

2 «Cours élémentaire de Paléontologie et de Géologie Stratigraphique,’ par M. D’Orbigny. 1850.

PRELIMINARY REMARKS. 3

étages Portlandien.
»» Kimméridgien.

»» Corrallien.
» Oxfordien.
. Terrain Jurassique . » Callovien.

», Bathonien.
» Toarcien.
», Liasien.

» Senemurien.

We are not struck with the superiority of this newly-proposed arrangement over the
one in common use, which we have adopted in the following pages, as it is never advisable
to burden science with fresh names when old ones serve the same purpose. To the late
Mr. Sowerby and other authors we are indebted for numerous correct descriptions of
many species from the Oolitic and Liasic series; but the recent impulse given to the study
of Palzontology has brought to light so vast an assemblage of new forms and better
_ representatives of several known ones, that it has been deemed advisable to reconsider and
publish, under the form of a series of Monographs, all the old species revised, annexing the
new forms due to the exertions of local geologists, who have done so much to advance
our knowledge of this and other classes, without whose assistance we never could hope to
achieve the laudable ends proposed by the Paleontographical Society and their liberal
and learned Secretary." Within the last few years, attempts have been made with more or
less success to throw light on the class of shells occupying us at present, through an
endeavour to classify them by their general affinities. Our object is simply to treat of the
Oolitic and Liasic species, comprising only a few genera, because we confine within more
general limits as many characters, said to be generic, which we consider to be only specific or
sectional differences, and which future discoveries will tend to generalise. How frequently
have gaps existing in the zoological chain of affinities’ been filled up of late years by the dis-
covery of forms unknown to early writers, proving how boundless the field of research is
in the kingdom of Nature, and how cautious we should be in assuming the uniform preva-

1 It is therefore pleasing to me to express my grateful feelings and sincere thanks for the kind
and liberal assistance I have received in the preparation of this work from MM. Bouchard, Deshayes,
Deslongchamps, Buvignier, Milne Edwards, Valenciennes, De Verneuil, Delessert, De Koninck, Morriere,
Chenu, &c.; from Messrs. Koinig, Waterhouse, Woodward, of the British Museum; Sir H. De la Beche;
Professor Forbes and Mr. Salter, of the Geological Survey ; the Geological Society’s Museum ; that of Bristol,
&e., where I was allowed to make use of the valuable collections deposited there; from Messrs. Bowerbank,
Walton, Moore, Morris, J. de C. Sowerby, Hugh Miller, Robertson of Elgin, M‘Coy, Rose of Swafiam,
Riply of Whitby, Marder, Bean and Leckenby of Scarboro’, Tennant, Faulkner of Deddington, Buckman,
King, Dr. Wright of Cheltenham, Mr. Cunnington of Devizes, Messrs. Lycett, Lowe, Griesbach, and others,
who have communicated to me the Paleontological treasures belonging to their respective collections.

2 For various reasons we have commenced with the species of the Oolite and Lias; but it is of little
importance, as this work is to be composed of a number of distinct monographs. Next year we hope to be
able to give the general introduction, in which we shall state our views on the classification and genera.

4 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

lence of characters by which we isolate Families or Groups from the remainder of their
class.

However much we may feel inclined to dispute the existence in Nature of genera and
species, as an abstract proposition in the Philosophy of Zoology, the admission of these
terms, and of the ideas we are accustomed to associate with them, are essential to the pro-
gress of science. This being the case, we ought at least to found genera in a uniform
manner, and to equalize as much as possible the value of the characters upon which they
are based, If, among the conchiferous molluscs, some trivial modifications in the position
of the processes which protect their valves from dislocation be admitted, as of generic
importance, we surely ought not in the Brachiopoda to place together shells of such
different structure, as we remark in 7. Carnea and 7. Concentrica. M. Deshayes formerly
admitted very few genera in the Brachiopoda; but from communications made by him to
me, I believe he now considers that a larger number are required from our present more
extended knowledge of the differences presented by the internal characters of the shell.
The value of these aids in the discrimination of genera is strongly insisted upon by
M. Deshayes in his great work upon the Paris Basin, where he states M. Blainville was
one of the first to remark, that, in the recent Terebratule the Apophysary lamella which
support the soft parts, present peculiar forms in each species, and adds, “Ce serait donc par
ce moyen que l’on pourrait déterminer rigoureusement les nombreuses espéces du genre.”

For many years our researches have been bent upon the discovery of those internal
characters; as we feel convinced that by them alone a rational and permanent classification
will in time be arrived at. ‘Through our exertions, and the help of many kind and zealous
friends, we have been able to examine the internal structure of most of our British species
which disposes us to admit the followmg genera among them :—

1. Lingula. 5. Lepteena.
2. Orbicula. 6. Spirifer.
3. Crania. 7. Terebratula.
4. Thecidea. 8. Terebratella.

9. Rhynchonella.

Many more have of late been proposed among our Oolitic species, but which we hope
to discuss in the general introduction, and shall merely here observe, that the greater or less
length of a simply attached loop in Terebratula cannot be made use of as a generic
character, especially when there exists no other distinctive pots. The length of the loop
may be used as sectional, round which we can group certain species; but who, with any
degree of confidence, would place in distinct genera such shells as Zer. Cornuta, quadrafida,
numismalis, obovata, digona, ornithocephala, &c., which have a simply-attached loop extending
to near the frontal margin of the valve, and those such as Ter. punctata, perovalis, Maz-
illata, intermedia spheroidalis, Coarctata, &c., the loop of which, simply attached to the
crura, only extends to less than half the length of the valve, while in others, such as
Ler. Carnea, Dyphia, &c.; the same process attached to the crura does not extend to more

PRELIMINARY REMARKS. 5:

than a fifth of the length of the shell. We have in vain attempted to find out some external
character by which we might discover if the species had a long or short loop; it had been
imagined that those with a long loop were flatter, depressed in the smaller valve, and with
lateral ridges of the beak strongly defined ; but this character falls to the ground when we
place im comparison such shells as Ter. perovalis and punctata, that have a short loop, with
Ter. ornithocephala, digona, and others with a long one, all possessing a similar convexity of
valves and other external characters. I have lately observed that the crura differs slightly
in those specimens with a short or long process, as may be seen from the figures illustrating
the interiors of Ter. Cornuta, resupinata, ornithocephala, &c., on one side, and those of
Ter. Mazillata, intermedia, spheroidalis, &c., on the other; and it will be perceived that in
the elongated looped shells the crural base is much larger, and forms a flat surface, which
does not exist in a similar manner in the others.

The punctures visible in Terebratulee and other genera cannot be used as a general
character to distinguish species, as the results of microscopical examination show us that
their size and form varies on the same shell, according to the portion placed under exa-
mination ; thus on one part we find the punctures widely separated becoming closer and
larger towards the edge until they assume a completely different appearance; and
although some species have a marked difference in this respect, others present no dis-
tinctions. Professor King, in his valuable ‘Monograph on Permian Fossils,’ goes too
far, in our opinion, while stating that he believes few Brachiopoda unpunctuated, as very
many shells in this class show no traces of punctures; but at the same time we believe
that many species considered unpunctuated are really so. It had been supposed, till very
lately, that the Zzasic species of spirifers were characterised and distinguished by being
punctuated, while other spirifers were not so; this opinion, must however, be abandoned,
from the fact observed by Professor King, that many carboniferous spirifers, very different
in shape and character, were likewise so, which has been also confirmed by M. De Koninck
and others. Before entering into the subject of this Monograph, we think it necessary to
state, that the confusion and contradictions we have found in authors were so great that
it has in many cases been no easy matter to find out the original types. Many of
Sowerby’s and Lamarck’s species, as well as those of other authors, have been singularly
misrepresented, and in fact have been but little understood by the generality of Paleeontolo-
gists and Geologists, who usually do not attach much importance to these determinations.

While reviewing the Lamarckian species of Terebratulze, I was surprised to find im that
celebrated collection many shells quite differmg in species from those intended by the
author of the ‘Min. Con.;’ and these errors seem so current abroad, that even the most
distinguished Palzontologists, such as Von Buch, Bronn, D’Orbigny, and others, have
placed in their catalogues, as Sowerby’s species, shells, differing completely, as will be
alluded to during the course of this work. Many of these mistakes are excusable, and
might have been expected, from the unfortunate foreshortened position in which that
author represented some of his shells. Through the kindness of Mr. J. de C. Sowerby, who

6 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

in the most liberal manner placed the original collection of the M.C. at my disposal; and
with the assistance of Mr. Waterhouse, we have endeavoured to clear up the original
types, some of which were merely synonyms, such as Ter. Triquetra, orbicularis, furcata,
lata, &e. &ec.

The difficulty I have encountered, in my endeavours to place the different shells hitherto
discovered in their proper places, is such, that I feel convinced numerous errors will have
been committed, which I hope other observers and future discoveries may correct. No class
of shells is more variable in their form, and the instances in which the former pass into
each other are so numerous, that. by some one or other character we might readily attach
most species together. We often forget, that among the species of Brachiopoda there must
have existed different races, as well as in those of other classes, arising from local conditions,
and by the httle attention paid to these circumstances species are made out of more
varieties. It is certain that many species were ornamented by colour, such as we perceive
among the recent shells; this colour, which would have been a great help, we are deprived
of; its existence, however, is proved by accidental specimens found occasionally possessing
traces of it,—we know that some Devonian species were spotted with red. er. Hastata,
Communis, and others irregularly and longitudinally striped, probably also with red, as we
see in Bouchardia rosea; and among the oolite species it is more than probable, from traces
discovered by M. Deslongchamps, that Rhynchonella spinosa was of a red colour, as well
as some of the cretaceous species. From the limited resources often left us by fossilization
we are not always able to trace correct boundaries to species; but we should endeavour to
do so where characters are sufficiently marked to be constant, and which may serve as
conventional points of comparison and reference.

After many years of researches, M. Deslongchamps’ published his views on the classi-
fication of the Brachiopoda found in Normandy—a paper I have long appreciated, but which,
to my surprise, is little noticed by those who have written on a similar subject. In it that
distinguished and conscientious author states, that after many different attempts to classify
the Brachiopoda, he found the best outward characters to consist in the shape and position
of the foramen; since which period Messrs. Morris, D’Orbigny, and others, have thrown
much additional light on this pomt by the discovery that the form of the internal Apophy-
sary system also bore intimate relations to the form and position of the beak, foramen, and
deltidium. This, moreover, appears to be the best mode of proceeding where the internal
characters are hidden from our view ; but, while this character is of generic importance, it
does not. always help us to separate species. M. Deslongchamps, in his table, proposes to
select a type and annex to it a number of allied forms, under the name of varieties: thus of
Ter. resupinata he mentions twelve varieties, of emarginata fifteen, of perovalis eleven, of
Concinna twenty, &c.; and he could have added many more had he operated upon a
larger collection; and although I completely agree with M. Deslongchamps as to the
reality of his varieties, still this system would, it is to be feared, lead to great confusion,

' Seances publiques de la Soc. Lin. de Normandie,’ 1837, p. 30.

PRELIMINARY REMARKS. ?

from the interminable list of perplexing varieties, impossible to be remembered. Several of
these M. Deslongchamps admits, such as Zer. Triguetra and Ornithocephala, themselves
only varieties of age and shape of the same species. We therefore think it preferable, for
the sake of convenience, to admit artificially more species and less variety; and, in order
to incorporate certain smaller variations, the description of a species should be so framed as
to embrace the general idea of the thus limited form rather than the account of a single
specimen.

Local causes and malformation, caused by pressure or fracture during the different
stages of growth, are not to be wondered at in a class of shells destined in general to
sedentary life, living and dying on the same spot attached to rocks, or in circumstances
where there existed a want of room for their complete development. These malformations,
alluded to by M. Deslongchamps, are much more common than generally imagined,
and have often been made into distinct species by different authors, from the inspection of
a single specimen. It is likewise certain, notwithstanding what may have been said to
the contrary by some more learned Palzontologists, that the limits in vertical range of
some species have extended to more than one group of strata, although species commonly
are characteristic, and restricted to narrow bounds. We must also allude to some technical
denominations made use of to denote the different parts of a shell; thus, for a considerable
period, and in many important works, the term dorsal has been applied to the larger or
perforated valve, and that of ventral to the smaller one. I do not wish here to contest
the observations which induced the celebrated anatomist, Professor Owen, to reverse the
denomination of the valves from the relative disposition of the animal to the valves, which
in some genera, such as Orbicula, would be the reverse of that in Terebratula. Because of
the immense confusion such a change would unavoidably create in works already pub-
lished, we have determined to banish completely the terms dorsal and ventral from our
descriptions, and to adopt other terms, also in use, to distinguish the same parts: thus we
will use indiscriminately the words perforated, rostral, or large valve, for the one considered
by De Buch and others a dorsal, the ventral of Professor Owen, and that of émperforated,
upper or smaller, for the lesser valve.

So variable are Brachiopodes in shape, size, gibbosity, &c., that we cannot employ
angular measurements proposed by Von Buch, as those characters vary in every specimen ;
‘nor do we attach much importance to the dimensions we give to each species. In general
we have taken those of the best developed specimen which has come under our notice.
Nor are the number of plaits more constant. We find the same species, especially among
the Rhynchonellas, have one, two, three, four, or more plaits on the mesial fold; thus most
species, smooth in the young, are plaited or otherwise ornamented at a more advanced
period of growth; it is therefore, in most cases, impossible to determine species from
young shells.

In concluding these few preliminary remarks, it is necessary to state, that merely the
synonyms and references likely to prove useful are inserted, as it would have been im-

8 BRITISH OOLITIC AND LIASIC BRACHIPODA.

possible to mention all the authors who have alluded to certain known species without
figuring or describing them. Many errors have been committed, and much confusion pro-
duced, by the rapid manner in which some authors have determined their species ; we will
not, therefore, refer to those which are published simply under the form of lists.

Genus—Lineuia, Bruguicre. 1789.

Shell inequivalved, one valve more convex than the other, more or less oval, elongated,
tapering and pointed at the beaks, widened at its palleal region, without hinge, valves
held together by the adductor muscles; attached to submarine bodies by a long muscular
peduncle issuing from between the beaks, a groove existing for its passage in that of larger
valves; arms fleshy, without any shelly support; structure horny, covered by an epidermis ;
two muscular impressions on the one, four on the other valve.

Obs. We are only acquainted with one authentic species of British Oolitic Lingula,
L. Beanii. Sowerby mentions another, Z. ovalis, as from Kimmeridge clay, but which
appears to belong to the lower green sand. It is worthy of remark, that the genus Lingula,
one of the oldest created forms, has persisted, with very little variation in shape, up to the
present day, a circumstance very unusual among the Brachiopoda.

1. Lineuna Brant, Phillips. Plate I, figs. 1, la, 14, le, 1d.

Lineuia Beani, Phillips. 1829. Geol. of Yorksh., Part i, pl. 2, fig. 26.
_ — Morris. 1843. Catalogue, p. 122.
cet — Dav. 1847. Lond. Geol. Journal, vol. i, pl. 18, figs. 26—30.
— — Bronn. 1849. Index Palzontologicus, p. 655.
— _— D'Orb. 1849. Prodrome, vol. i, p. 286.

Diagnosis. Shell irregularly oblong, oval, rounded in front; valves thin, convex, with
numerous concentric lines of growth; internal muscular impressions strongly marked.
Dimensions variable; average size 10 lines long by 6 broad.

Obs. Professor Phillips was the first to notice this species in his work on the ‘ Geology
of Yorkshire,’ but gives no further description than that it approaches Ling. mytiloides of
Sowerby. From the great resemblance various species of Zingula bear to each other, it is

1 From the necessity of bringing out the work in parts, and from the strong aversion we have to the
objectionable practice of giving lists of new species before they are described and figured, we cannot here
give the tables and general conclusions as to the distribution of the various species till the conclusion of the
series of Monographs on these subjects.

* For more ample details, see general Introduction.

ORBICULA. 9

often difficult to distinguish and describe them. Professor Phillips states this species to
occur in the inferior Oolite of Yorkshire; it has also been found in the marlstone near
Bathford, durmg the cuttings for the Great Western Railway, by Mr. Walton, whence
the fine internal specimens figured in Plate I, figs. 1, a, 4, c, d, were obtained; these
figures are enlarged.

I do not know any other English Oolitic species; fragments of a Lingula have been
found by Mr. Moore in the upper lias of Ilminster, but not sufficiently perfect to be
described or identified.

Figs. la, 14, represent the larger valve enlarged, with the groove for the passage of the
muscular peduncle. .
Figs. 2¢, 2d, smaller valve enlarged. It will be seen by these figures the muscular

impressions vary slightly in different specimens.

Genus —OrpicuLa, Cuvier. 1798.

Shell mequivalved, more or less orbicular, upper valve conical, with apex nearer the
posterior margin, smaller valve depressed, flat, or slightly convex, affixed to submarine
bodies by a tendimous pedicle issuing through a fissure, varying in length and size,
extending from its centre to near the margin; no hinge, or calcareous shelly supports ;
structure horny.

Obs. We are only acquainted with three British Oolitic Orbicule, viz., O. Zownshendi,
refexa, and Humphresiana; O. Townshend: is the largest orbicula known. ‘Two other
shells have been placed among the orbicula: O. granulata, Sow., M.C., Tab. 506, fig. 34,
stated to be from the great Oolite of Ancliff, and O. radiata, Phillips, Geol. of York,
Tab. 4, fig. 12, as from cor. Oolite of Malton; these, however, do not seem to belong to
the class of Brachiopoda, but to that of Gasteropodes.

2. OrpicuLa TownsHEnpdI, Forbes, MS. Plate I, figs. 2, 2a, 20.

Diagnosis. Shell bivalve, thin, almost circular, upper valve very convex, regularly
rounded; apex near the posterior margin, greatest elevation of the valve towards the
central part, the apex lying considerably lower; surface smooth, horny, with irregular
circular lines of growth; inferior or attached valve, slightly concave, with deep depression,
extending and widening from the centre to within a short distance from the posterior
margin, leading to a long, wide, ovular fissure, from which the peduncular fibres issued,
and which must, in this species, from the depth of the valve, have been of some length,
the fissure measuring 5 lines in length and 3 in breadth, and extending to within
4 lines of the margin of the shell. This valve is ornamented by numerous and regular
slightly-elevated concentric striz, not all forming the complete circle, sometimes extending

c

10 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

only to a certain distance, while at other times they dichotomize or unite into strong,
wide striz, especially towards and between the fissure and anterior margin. Interior
unknown ; length and breadth 19, depth 7 lines.

Obs. This is the largest and finest species of orbicula with which I am acquainted,
and only approached by a specimen shown me by M. D’Orbigny, from the lias of France,
believed to be distinct by that author, both species forming part of a sub-genus among
the orbicule proposed by him, under the name of Ordiculoidea.

I am indebted to the liberality of the Geological Survey for the loan of this magnificent
specimen, forming part of their collection, and named by Professor Forbes after the late
Mr. Townshend, who found and bequeathed it to that establishment. Unfortunately the
ticket has been lost, but I am assured that it is from the Oxford clay beds of the southern
districts of England.

3. OrBICULA REFLEXA, Sow. Plate X, fig. 8.

ORBICULA REFLEXA, Sow. 1829. M. C., vol. vi, p. 4, pl. 506, fig. 1.
— — Zool. Journal, vol. ii, p. 321.
— — Morris. Catalogue, 1843.
_ — Bronn. 1849. Index Palzont., p. 848.
ORBICULOIDEA REFLEXA, D’ Orb. 1849. Prodrome, vol. i, p. 258.

Diagnosis. Shell bivalve, subelliptical, thin, upper or unattached valve convex, with
apex directed towards and near the posterior margin; surface shining and smooth, with
the exception of numerous fine concentric lines; structure horny; lower or attached valve
nearly flat; aperture for the muscular byssus large and elongated. Length 7, breadth 6,
depth 3 lines.

Obs. Two fine specimens of this orbicula are to be seen in the collection of the
British Museum, attached to an arca, and said to be from the las of Northampton. We
find Peak Whitby mentioned by Mr. Morris, but never having found the shell in situ can
add no other details. It has sometimes been mistaken for a similar but more circular
orbicula, found in the coal measures of Coalbrook dale, and it seems even probable that
Sowerby’s figures were drawn from some specimens of that species.

4, Orsicuta Humpuresiana, Sow. Plate I, ‘figs. 3, 3a, 34.

OrpicuLa Humpnresiana, Sow. 1829. Vol. vi, p. 5, pl. 506, fig. 2.
_ — Morris. 1843. Catalogue.
— — Bronn. 1849. Index Paleont., p. 847.

Diagnosis, Shell bivalve, more or less circular, conical, apex elevated at some distance
from the posterior margin; surface of upper valve ornamented by numerous longitudinal
diverging strize, from the apex towards the marginal line; lower valve unknown, attached
to ostrea deltoidea. Length 6, breadth 5 lines.

CRANIA. ll

Obs. The only specimens I have seen and figured in my Plate I. are from the
collection of Mr. Sowerby, and would appear to have been found in the Kim clay,
Shotover, Oxon. Fig. 3a is an enlarged illustration. Among the recent species we find
more than one longitudinally striated. O. Cummigii, &c.

Genus—Crantia, Retzius. 1781.

Shell unequivalve, circular or subquadrate, more or less irregular, entirely or partially
attached by the substance of smaller valve to rocks, corals, and other submarine bodies ;
upper valve conical, with lateral or subcentral vertex, without hinge or ligament ; lower or
attached valve thickest, often irregular, due to the nature of the object to which it is fixed ;
surface strongly punctured or spongy; four circular depressed, or produced muscular
impressions in each valve, the first two, formed by the adductor muscles, are situated near
the cardinal edge, the other pair are approximated and placed near the centre, behind
which a central prominence is sometimes seen; the space between these and the wide,
thicker, granular margin surrounding the shell, is divided by the digitated genito-
vascular impressions; arms fleshy, free only at their extremities; no calcareous supports.

Obs. We are only acquainted with two British Oolitic cramias, C. Antiguior and
C. Moorei, and, unfortunately, of these only one of the valves has been hitherto discovered.

5. CRANIA Anviauior, Jelly. Plate I, figs. 4—8.

CRANIA ANTIQUIOR, Morris. Catalogue, 1843.
— — Dav. Uondon Geol. Journal, vol. i, pl. 18, figs. 21—25. 1847.
a _- Bronn. Index Paleont., p. 342. 1849.
— — D’Orb. Prodrome, vol. i, p. 316. 1849.

Diagnosis. Shell suborbicular, irregular, the lower valve only known; it varies
in form, some specimens being almost flat, others more or less concave, and even occasion-
ally patelliform. The muscular impressions are four, more or less; strongly marked in
different examples; the two posterior are generally larger and more widely separated than
the two anterior ones, which latter usually touch, and are also less circular in form than
the upper, and depressed in the centre. In most examples a strongly-marked ridge is
seen extending in the mesial line, from the junction of the lower muscular impressions to
the margin of the shell, as displayed in fig.8. The very peculiar spongeous structure,
characteristic of the genus Crania, is well marked. In form and general appearance this
species somewhat approaches Crania abnormis of the tertiary period. Length 7, breadth
63 lines; some specimens are almost square. From the appearance of the exterior this
Crania would not seem to have been much attached.

Obs. A very extensive series of specimens of this species, forwarded to me by

12 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Mr. Walton and Mr. Pearce, of Bath, as well as numerous specimens collected by myself,
have enabled me to note the extreme variations exhibited in its general form and shape of
the muscular impressions. Sometimes these impressions project in the prominent manner
shown by figs. 4, 6, 8, while at other times they are barely distinguishable; in one speci-
men, belonging to Mr. Pearce, the whole four, where actually depressed, producing a remark-
able concavity in the valve. Mr. Pearce was at first disposed to consider these specimens
as examples of the upper valve, an opinion, however, he afterwards relinquished ; and,
curiously enough, although many hundreds have been collected by Messrs. Walton and
Pearce, they have not been able to obtain the upper valve in any one instance.

This species was originally discovered by the Rev. H. Jelly, who applied to it the
specific appellation “ Antiquior,” but no figure or description appeared before May, 1847,
when I described and figured it in the London Geological Journal, the only published
record respecting it being the insertion of this name in Mr. Morris’s valuable Catalogue
of British Fossils, in 1843.

The Crania Antiquior is found in the great Oolite of Hampton Cliff, near Bath; the
specimens figured are from the collection of Mr. Walton.

All the figures are of natural size, except fig. 8, which is enlarged.

6. Cranta Moorti, Dav. Plate I, fig. 9.

Diagnosis. Shell irregular, transversely oval, suborbicular, truncated posteriorly ;
upper valve convex and slightly conical, with the vertex near the centre; surface smooth
and punctuated ; interior presenting four muscular impressions, the posterior ones slightly
marked, as well as the anterior two, which are arranged in the form of aV. The digitated
genito-vascular impressions hardly visible; imterior closely punctuated. Length and
breadth about 1 le. The upper valve only is known.

Obs. This small species was found by Mr. Moore, in the upper lias, near Ilminster ;
its position is higher than that of those beds containing the Leptcenas in the same locality.
The figure is drawn from a specimen kindly given to me by Mr. Moore, and I take great
pleasure in naming the species after him.

Plate I, fig. 9, natural size. Fig. 9, a, 4, enlarged.

Genus—TueEcipEA, Defrance. 1828.

Shell unequivalved, thickened, more or less irregular ; largest valve partially or entirely
attached by its own substance, or, when young, in some species by a peduncle issuing
from the extremity of the beak to submarine bodies; form longitudinally or transversely
oval, sometimes subquadrate ; upper valve small, more or less convex, smooth, or other-

THECIDEA. 13

wise ornamented, granulated, structure punctuated hinge line more or less straight, with
two strong teeth im the attached valve, adapting themselves into corresponding sockets in
the smaller valve; beak more or less produced, with long or wide well-defined area and
deltideum. Interior of valves variable; in larger valves a longitudinal, central, and two
lateral ridges are generally more or less visible, under which two deep muscular impres-
sions are seen; upper valve complicated, more or less deeply and regularly sinuated by an
apophysary testaceous ridge, united all round, and leaving a small cavity in the upper
portion of the valve free for the body of the animal, these smuated ridges varying in
number, position, and extent in different species; two strong lateral adductor muscles
situated under the hinge, no arms, animal small.

Obs. We are acquainted with five British Oolitic species of Thecidea, four from the
Lias, a fact hitherto unrecorded, and two in the Inferior Oolite.

7. Tuecipua Moorzi, Dav. Plate I, fig. 10.

Diagnosis. Shell irregular, inequivalved, attached by the greatest portion of its
inferior valve, almost square; attached or lower valve, modelling itself to the object on
which it is fixed, with elevated sides and front rising perpendicularly from the attached
part; area well defined, triangular, and receding from its junction with the upper valve ;
deltidium large, elevated with slight central depression, and marked, as well as the area,
with numerous lines of growth. Upper valve almost flat, of a transversely oblong square,
with slight depression im the centre, and the sides, except at the hinge, turning sharply
over, and forming elevated sides, till they meet the edge of the lower valve, so that the
front is very much elevated. Surface strongly punctuated ; interior of attached valve only
known; hinge line straight, with two strong teeth and elevated mesial ridge. Length
and breadth about 2 lines; frontal elevation 1 line.

Ods. ‘Twelve specimens of this remarkable little Thecidea were found attached to a
specimen of Rhynchonella serrata, from the marlstone or middle lias in the neighbourhood
of Ilminster, along with Thecidea Bouwchardii and triangularis, by Mr. Moore, to whom
I feel much pleasure in dedicating the species. These and another, 7. rustica, are the first
specimens of this genus hitherto noticed, as far down as the Liasic period; no mention is
made of this genus in M. D’Orbigny’s Prodrome; they would appear to be the oldest
Thecideas at present known. Mr. Moore also has one specimen of this species, found in
the upper lias, from the neighbourhood of Ilminster. 7%. Moorez is easily distinguished
from all other known Thecideas, by its square shape and elevated front.

Plate 1, fig. 10, illustrates specimens of natural size, from the collection of Mr. Moore ;
fig. 10, a—e, are enlarged.

14 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

7
8. Turcrpra Bovcnarpi, Dav. Plate I, figs. 15, 16.

Diagnosis. Shell irregular, inequivalved, of an elongated transversal form, attached
by the greatest part of its lower valve; area in larger valve long and straight, receding
from its junction with the upper valves, and at almost right angles to it; deltidium well
defined, elevated, and marked by lines of growth, which extend also over the area; upper
valve slightly convex, smooth, and strongly punctuated; greatest height at hinge line
receding thence to the frontal margin. Interior of attached valve only known ; hinge line
straight, with two strong teeth and internal elevated mesial ridge, and wide, strongly-
granulated margin, leaving two deep depressions on each side of the central elevated
ridge. Length 14, breadth 2 lines.

Oés. Three specimens of this species were found attached to the same specimen of
Rh. serrata, or along with 7h. Moorei, and consequently from the middle lias, and I feel
much pleasure in dedicating it to M. Bouchard; its locality is the neighbourhood of
Ilminster. M. Tesson, of Caen, showed me a specimen of Thecidea, which approaches this
very much in fofm, and is found in the liasic beds of Fontaine Etoupe Tour, near Caen, in
Normandy, and I should not have hesitated in saying it was the same species, had the
dimensions of the French specimen not exceeded three times those of our English shell.
Th. Bouchardii is easily distinguished from the other forms of this genus by its great
breadth, and appears a much more delicate species than either T’. Moorei or 'T’. triangularis.

Plate I, fig. 15, natural size of a specimen in Mr. Moore’s collection; figs. 15a, 16,
and 17, enlarged views.

9. Tuxcipza Dicxinsonil, Moore, MS. Plate XIII, fig. 19.

Diagnosis. Shell of an elongated transversal form, unequivalved, and attached by the
greatest part of its lower valve; area and cardinal edge straight, and not quite as long as
the greatest width of the shell; upper valve slightly convex, smooth, and punctuated.
Length 15, width 23 lines.

Obs. This is the largest Inferior Oolite Zhecidea, I believe, as yet known, and
is attached to a specimen of Zer. perovalis, from Dinnington, belonging to Mr. Moore, who
named it after his friend Mr. Dickinson. We find also, in the same locality, Zhecidea
triangularis, which is easily distinguished by its shape.

10. Turcipza Trianevtaris, D’Ord. Plate I, figs. 11, 12.

THECIDEA TRIANGULARIS, D’Oré. (?) 1849. Prodrome, vol. i, p. 316.

Diagnosis. Shell irregular, inequivalved, attached by the greatest portion of its lower
valve, more or less triangular, gibbose, produced behind, and somewhat bilobate in front ;

THECIDEA. 15

area of attached valve triangular, more or less lengthened, with distinct deltidium; small
valve operculiform, convex, with slight depression in centre, punctuated; the interior of
attached valve only known. Length 1 line, breadth the same.

Obs. I believe this to be the same species as M. D’Orbigny mentions, but which
he neither describes nor figures in his Prodrome, under the name of Zh. triangularis, as
occurring 1n the Oolitic beds of Ranville, in Normandy, and which name I will here adopt,
as, on comparing it with our English specimens, I could find no difference.

In England this species appears to have first appeared m the middle lias, as Mr.
Moore found it attached to RA. serrata, and it was afterwards found by Dr. Wright,
Mr. Morris, and myself, in the Inferior Oolite of the Cotswold and Leckhampton hills,
attached to Zer. plicata, Rh. Wrightit, to corals, and to probably any other shell in that
bed. In Normandy it is found a little higher up.

This species also strongly resembles (except in size) the recent Thecidea Mediterraneum,
as may be easily perceived on looking at the figure of that species, (Plate I, fig. 13,) which
I have purposely placed by the side of Zhecidea triangularis. Our fossil species does not
appear, however, to have ever attained the dimensions of the recent species.

Plate I, fig. 11, natural size of Mr. Moore’s specimen from the marlstone; fig. 11,
a, b, enlarged view of the same. Plate I, fig. 12, natural size of one of the Inferior Oolite
specimens; 12a, enlarged. Plate I, fig. 13, recent Zhecidea Mediterraneum.

11. Taecrpea Rustica, Moore, MS. Plate I, fig. 4.

Diagnosis. Of this small Thecidea we are acquainted with only the upper or
unattached valve, and therefore the description must consequently be very incomplete.
Unattached valve slightly convex, of a squarish circular form, as long as wide, smooth and
punctuated, interior presenting two sockets, in which the teeth of the unattached valve
articulate from under an elevated crest or lamella, surrounding the shell at some distance
from the edge, and, on reaching the frontal margin, it takes a curve towards the middle
of the valve; returning again to the margin, it terminates under the other socket, the
position between this ridge and the edge of the shell being strongly granulated, and
presenting another smaller ridge, which also joims the sockets, after having gone
round the shell. The sinuses observable in Zhecideas, and which form so many
elevations in its centre, are hardly perceptible in this species; there is a slight elevation,
strongly granulated, on each side of the first described ridge. Length 1 line, breadth the
same.

Obs. The internal organisation of this species is more simple than that generally seen
in Thecidea, but it must also be observed that the number of the lamelle, or ridges, forming
the sinuses in this genus, and which represent the calcareous supports in ‘Terebratula, vary
very much, as may easily be perceived, in casting a glance over Zhecidea hippocrepis, tetra-

16 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

gona, papillata, hieroglyphica, recurvirostris, digitata, antiqua, &c. This last-named species
approaching more than any I know to our 7%. rustica, and in all good genera we ought to
find a graduated scale from the simple to the compound. 'Thecidea rustica was discovered
by Mr. Moore in the upper lias, in the same bed contaming Lept. Moore:, Bouchardic,
Liasiana, Pearcei, Sp. Ilminsteriensis, &c., and therefore higher up than 72. Moorec and
Bouchardii. Myr. Moore has given it the name of 7h. rustica, which I readily adopt ; it is
much to be regretted that hitherto only the smaller valve has been found; it does not
appear very rare in its bed, if one inclines to take the trouble of seeking it, which can be
done only by washing the sandy clay bed where it is found, and then carefully picking them
out, after having extended small portions of the washed bed ona plate. In this manner, also,
are obtained the Zeptenas, and numerous Foraminifera with which these beds abound ;
its locality is the neighbourhood of Ilminster.

Plate I, fig. 14, natural size, from specimens belonging to Mr. Moore; fig. 14, a, 4,
enlarged exterior and interior.

Genus—Lrrrana, Dalman. 1827.

Shell inequivalved, equilateral, generally transverse, sometimes oval, always compressed ;
smooth, striated, or exteriorly costated : /arger valve, more or less convex or concave, some- °
times bent or geniculated ; beak more or less produced, straight, sometimes recurved, and
perforated at its extremity by a very small circular opening ; separated from the cardinal
edge by a more or less elevated triangular or canaliculated area: smaller valve, concave or
convex, following the large valve in its different curves, beak of smaller valve not much
produced, with or without a linear area: deltideum complete, triangular, with angles more
or less open, without reference to the development of the area; often notched at its base for
the passage of the tendinous fibres of attachment ; hinge transverse, straight, linear ; teeth
differently disposed, but always provided with two principal diverging teeth on the larger
valve, which are received by sockets placed on each side of the central bifid or trifid tooth
of the smaller valve: no internal calcareous supports.

Obs. We will not at present discuss the different opinions lately brought forward on this
genus, or its subdivisions, each author having his way of thinking on this subject, which
has involved us in great confusion; the same shell is thus for some. a Strophomena, for
others a Leptena, Leptagonia Chonetes, Productus, &c. All we shall here state is, that
the genus was not known to occur above the Palzeozoic series before 1847, at which time
M. Bouchard and myself described several species from the lower oolitic or liasic
deposits ; and we are now acquainted with the five following species :—Leptena Moorei,
L. Piercei, L. granulosa, L. liasiana and L. Bouchardii, all of which are found in
England. Lept. liasiana (Bouch.) alone having as yet been discovered on the Continent.

LEPTANA. 17

12. Leprena Mooret, Dav. Plate I, fig. 18.

Lert@na Mooret, Dav. 1847. Annals and Mag. of Nat. Hist., pl. xviii, fig. 1 a.
— — Dav. Bull. Soc. Géol. France, vol. vi, 2d Series, p. 270.
— — D’Orb. Prodome, vol. i, p. 220, 1849.

Diagnosis. Shell small, depressed, wider than long, ornamented by numerous fine
costa, scarcely visible without a lens; larger valve slightly convex; area double, as wide,
or rather wider, than the shell; deltidium small, chiefly filled up by the median tooth of
smaller valve, which tooth is grooved by four furrows, offering a passage for the muscular
fibres of attachment passed outwards. Length 13 lines; width 2 lines.

The muscular impressions in the interior of both valves are strongly developed in
this species, and indicate that it did not attam larger dimensions than those above
assigned to it. ¢

This elegant little species was first discovered in the beds of the upper lias above the
marlstone, near Ilminster, by Mr. Moore, to whom it is dedicated. The following section,
forwarded by Mr. Moore, shows the position of the bed containing the Leptenas :—

1. Rubbly beds, 6 to 10 feet, with numerous Ammonites.

2. Clay, 8 inches.

. Yellow limestone, 3 to 4 inches.

. Layers of clay, 18 inches, Leptena Pearcei.

. Lepteena bed, 1 inch: LZ. Moorei, L. Bouchardii, and L. liasiana.
. Marlstone, 24 inches.

. Greenish sand, 4 inches, containing numerous Belemnites.

con® of oO

. Marlstone.

I do not understand the reason which has induced M. D’Orbigny to place these
Leptenas, and other species found in the same beds, in the lower Lias (Senemurien,
Prodrome, p. 220), where none, to my knowledge, have been discovered according with
my printed description and stratigraphical position of the species, which has not been
noticed out of England as yet.

Plate I, fig. 18, shows the exact size of an adult specimen of this species.

» fig. 18 a—e are enlarged.

It is not a rare species in its bed, Mr. Moore having found more than one hundred

specimens ; but from its minuteness it is difficult and tedious to collect.

13. Leerana Prarcet, Dav. Pilate I, fig. 19.

Leprrmna Prarcet, Dav. 1847. Annals and Mag. of Nat. Hist., pl. 18, fig. 4.
— — Dav. Bull. Soc. Géol. de France, vol. vi, 2°° Série, p. 270, 1850.
_ a D’ Orb. Prodrome, 1849, vol. i, p. 220.
D

18 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

The larger valve only of this small species is known; from which it appears, that it
differed materially from Z. Moore7, being much more convex, and the strize ornamenting
its surface having two or three smaller intermediate ones (Plate I, fig. 194); while in
L. Moorei the coste appear of the same size; the shape of this shell is also more rounded,
and considerably larger than Z. Moorei. Length 33; breadth 43 lines,

This species appears to be rare; it occurs in a clay stratum above the Leptena bed :
it was discovered by Mr. Moore.

Plate I, fig. 19, nat. size; fig. 19a, 4, enlarged.

14. Luprana cranuLosa, Dav. Plate I, fig. 20.

LEPTENA GRANULOSA, Dav. Bull. Soc. Géol. de France, vol. vi, 2% Serie, p. 270,
fig. 6, 1850.

Diagnosis. Valve slightly convex, rounded and ornamented by granulous strie,
between which smaller ones are perceived (Plate I, fig. 200); the area appears narrow,
and has much resemblance to Z. Moorez. Length 13; breadth 2 lines.

It is a rare species; easily distinguished from ZL. Pearce: and L. Moore: by the
granulations which ornament its valves: it was found by Mr. Moore in the upper Lias,
in the same bed which contains LZ. Pearcei. Only the larger valve is known, and therefore
it can be but imperfectly described.

Plate I, fig. 20, natural size.
fig. 20a, 6, enlarged.

29

15. Leprmna tiastana, Bouchard. Plate I, fig. 21.

LEpTHNa LIAstaNA, Bouchard. 1847. Annals and Mag. of Nat. Hist., t. 18, fig. 2, a—d.
— — Dav, 1850. Bull. Soc. Géol. de France, vol, vi, 2° Série, p. 270.
— — D’ Orb. Prodrome, vol. i, p. 220.

Diagnosis. “Shell rounded, inequivalved, equilateral, smooth ; larger valve gibbose pos-
teriorly, becoming flatter anteriorly, with a slight longitudinal groove ending in a notch on
the front margin of the shell. Beak small, slightly incurved, truncated at the apex by a
minute circular foramen, similar to that which occurs in many other Leptenas; for instance,
L. alternata, of Indiana, North America. This truncation may also be observed in some
species of Orthis, from Russia. Area double, interrupted on the dorsal valve by a large
and slightly-convex deltidium, which arises at the apical opening, and gradually enlarges
towards the base, occupying one third of the width of the area. The deltidium is slightly
notched, the notch being partly closed by the large median tooth of the smaller valve; the
exterior face of which is grooved by four furrows, which afforded a passage for the muscular
fibres of attachment, arranged in four bundles. The smaller valve is deeply concave, fol-

LEPTANA. 19

lowing the contour of the larger valve, so that little space remained between them for the
body of the animal. Cardinal margin about half the width of the shell. Length 2 lines;
breadth the same. .

“The general form of this Zeptena approaches that of Productus. It closely resembles
L. oblonga. (Pander.) It has the same convexity and smoothness, and the beak is similarly
truncated by an apicial opening: the area and perpendicular opening has also some analogy
to the Russian species, but differs in the contour of the larger valve, and the notch in the
front margin.” (Bouchard.)

Oés. ‘The above description was published by M. Bouchard, in the ‘ Annals of
Natural History,’ Oct. 1847, and I have thought it desirable to reproduce it here. At
that period this species had not been discovered in England; Mr. Moore was so fortunate
as to find in my presence, a short time since, two fine specimens in the Leptena beds of
the upper Lias, in the neighbourhood of Ilminster: its foreign locality being Pic de Saint
Loup, near Montpellier (Herault). In the ‘ Prodrome,’ page 220, M. D’Orbigny, besides
placing this species and LZ. Bouchard m the lower Lias, which is a stratigraphical
mistake, states it not to be a Leptena. It is to be regretted that, with both perfect
figures of the exterior and interior, M. D’Orbigny did not assign its generic position ; but
both M. Bouchard and myself consider its place for the present to be best among the
Leptenas, with which they have many similar characters.

Plate I, fig. 21, natural size.

» fig. 2la, enlarged.

XVI. Leprana Bovonarpu, Dav. Plate I, fig. 22.

Lepr£na Boucwarpit, Dav. 1847. Annals and Mag. of Nat., Hist., pl. 18, fig. 3.
—_— _ Dav. 1850. Bull. Soc. Géol. de France, vol. vi, 2° Série,
p- 270. 1850.
— — ? D’Orb. Prodrome, 1849, vol. i, p. 220.

Diagnosis. Shell very small, almost ovular; surface smooth; large valve very convex,
smaller valve concave, leaving only a little space for the animal; beak small, not much
recurved ; area double, and cardinal margin smaller than the greatest width of the shell ;
deltidium very large. Length 14; width about half a line.

Oés. This species is readily distinguished from Leptena lasiana by its more elegant
form ; the small valve is more regularly concave, and the larger one more convex. When
describing this species in the ‘ Annals,’ I had not perceived that the beak was truncated at
its extremity by a minute circular foramen, as in Z. Masiana; but which numerous speci-
mens, sent to me by Mr. Moore, have amply confirmed. This species appears never to have
attained larger dimensions; as the internal characters presented by the smaller valve are
those belonging to a full-grown shell. LZ. Bouchardii was found, by Mr. Moore, associated
with Leptena Moorei, in the Leptena bed, previously described under that species.

Plate I, fig. 22, natural size.
fig. 22a, 6, c, enlarged.

>

20 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Genus—SpiriFEer, Sowerby. 1818.

Shell unequivalved, equilateral, generally transverse, more or less trigonal, and convex.
Exterior rarely smooth, more often striated or costated ; larger valve always convex, often
gibbous, divided by a medio-longitudinal sinus, of more or less depth and width, cor-
responding with the mesial fold in smaller valve. Beak generally acute and straight,
sometimes recurved and obtuse, never truncated, area always triangular, more or less
elevated ; thrown backwards, flat or concave, and divided by a mesial deltideal fissure,
always covered by a deltideum, notched at its base, for the passage of the peduncular fibres.
Smaller valve always convex, but less so than in larger valve; longitudinally divided by a
mesial fold, elevated and proportioned to the sinus in larger valve, to which it corresponds.
No area, summit not much developed, extending a little beyond the rectilineal cardinal
edge ; hinge straight, transverse, formed of two diverging teeth, limiting the base of the
deltoid fissure of larger valve, and placed in the sockets existing on each side of the beak
of the smaller valve; internal calcareous supports formed by two lamellz, arising from
under the beak of smaller valve, and forming a number of spiral coils, diminishing in size
towards the cardinal angles.

Obs. Several divisions have been proposed in the Genus Spir7fer, to which we will allude
in our introduction, and shall only notice here, that the punctuated character believed
to be peculiar to Lias Spirifers (Spzriferina, D’Orb.), also exists in those of other epochs.
In our British Oolitic series, we are only acquainted with four species of Spirifer: viz.,
Spirifer rostratus, Sp. Ilminsteriensis, Sp. Walcottii, and Sp. Miinsterii, all found in the
has. And on the Continent four or five more have been discovered; so that this genus,
which has not yet been known higher up in the series, was represented by eight or nine
forms, some of which are very similar in exterior appearance to more ancient types.

17. Sprrirr rostRatus, Sch. Plate II, figs. 1—21; Plate III, fig. 1.

TEREBRATULITES RosTRATUS, Schlotheim. 1822. Nach. Zur. Petrefact., pl. xvi.
De.ruyris verrucosa, V. Buch. 1831. Petrifications Remarquables, pl. vii, fig. 2.
SPIRIFER ROSTRATA, Zieten. 1832. Die versteinerungen Wurttemberg, p. 38, fig. 3.
— MESOLOBA, ? Phil. Deslongchamps. 1837. Soc. Linn. de Normandie.
— Harrmantt, Zieten. 1838. Die Verst Wurttemberg, pl. xxxviii, fig. 1,
veRRUCOSA, Zieten. 1838. Die Verst Wurttemberg, pl. xxxviii, fig. 2.
_ PINGUIS, Zieten. (non Sow.) 1838. Die Verst Wurttemberg, t. xxxviii, fig. 5.
De.ruyris rostratus, V. Buch. 1840. Class. et descrip. des Delthyris, Mém. Soc.
Géol. de France, 1°° Série, t. iv, pl. 10, fig. 24.
_— verrucosa, V. Buch. 1840. Class. et descrip. des Delthyris, Mém. Soe.
Géol. de France, 1‘ Série, t. 4, pl. x, fig. 30.
— tumipus, V. Buch. 1840. Class. et descrip. des Delthyris, Mém. Soc.
Géol. de France, 1°° Série, t. 4, pl. x, fig. 29.

——

SPIRIFER. 21

Dettuyris HarrMantt, Quenstedt, 1843. Das Fléegibirge, Wiirtemberg, p. 181.
= VERRUCOSA, Quenstedt. 1843. Das Floegibirge, Wiirtemberg, p. 185.
_ ROSTRATA, Quenstedt. 1843. Das Fléegibirge, Wiirtemberg, p. 186.
SPIRIFER PUNCTATUS, Buckman. 1845. Geol. of Chelt., pl. 10, fig. 7.
— ReTICULATUS, Buckman. (MS.)
— LINGUIFEROIDES AND CHILIENSIS, Forbes and Darwin. 1846. South
America, p. 267, pl. 5, figs. 15, 16, 17, 18.
— Rostratus, Dav. 1847. London Geol. Journal, vol. i, p. 109, pl. 18,
figs. 1—10.
SPIRIFERINA GRANULOSA, Reemer (according to M. D’ Orbigny). 1849. Prodrome, p. 5
— verrucosa, D’Orb. 1849. Prodrome, vol. i, p. 221.
— Harrmanu, D’Orb. 1849. Prodrome, vol. i, p. 229.
SPIRIFER ROSTRATUS, Bronn. 1849. Index Palzont., p. 1181.

o
lop)

— tTumipus, Coqguand et Bayle. 1850. Bull. Soc. Géol. de France, vol. vii,
2* Série, p. 235.

Diagnosis. Shell iniquivalved, variable, rounded, with mesial fold and sinus more or
less prominent; surface smooth or undulated, forming sometimes rounded plaits; beak
more or less developed, recurved or straight ; deltidium in two pieces, area well defined,
surface of valves punctuated, and spinose extending only to the edge of the area. Three
lamellze are seen in the interior of large valve, the central one more elevated, and termi-
nating in a pomt; in small valve, two spirals united together by a Jamella. Length and
depth very variable, the largest specimen known measuring—length 28, width 30, depth
17 lines; but the dimensions are generally much smaller, rarely extending 10 lines in
length, and the same in breadth.

Ods. The numerous variations in size and form assumed by this species, does not admit
of a correct description; but, through a numerous suite of specimens, we are enabled to
trace the passages from one variation of form into another, all preserving a general aspect,
leading to the most common type. Since 1845, I have devoted much attention to this
species, having had at my disposal a great number of specimens from our British and
foreign localities, it being abundantly spread in different beds of the liasic period, and a
few of the most marked variations are illustrated in Plate IL; and, had space admitted of
it, the intermediate passages could have been traced. All the figures, excepting 18 and 19,
are of the natural size; fig. 1 represents the largest specimen yet known of the species,
which varies in size from the one first mentioned to that of a pea. The average dimensions
and shapes are illustrated by figures 1, 2, 5, and 7.

The great variations to which this species is subject appear attributable to three principal
causes :—First. The presence of a mesial fold and sinus more or less developed, or its total
absence, as seen in some specimens where the front is quite straight (figs. 4 and 10); at
other times only a gently elevated curve is perceptible, as in fig. 11. The large valve being
regularly convex to the front, and no sinus existing, as generally happens when there is a
mesial fold, more or less produced, as in figs. 1, 2, and 7. ‘The second cause exists in
the tendency there is in certain specimens to undulation, which, becoming close, often

22 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

give the shell a plaited look; these, however, are not true plaits, but undulations, as in
fig. 7, which is the most marked example I could find; in general they are hardly visible,
and do not extend to the umbo, as in Sp. Walcotti, Miinsterii, &c., and we can trace
every stage, from the perfectly smooth specimen to the extreme state represented in fig. 7.
The third cause is occasioned by the form of the area and beak, which is very variable in
this species; generally the beak is recurved, as in figs. 1, 2, 4, 5, and 7, allowing one to
see under it a deltidium of moderate size; but as the area and beak become produced
and projected backwards (which is the case with many specimens), the beak becomes almost
straight or slightly recurved at its extremity, and displaying in all its extent a large
elongated deltidium, which is the narrower in appearance as the area becomes longer and
larger. The deltidium does not thus widen in comparison to its length; it would, there-
fore, be impossible to separate into species this shell from the form and size of its area and
beak, as every insensible gradation can be traced from one shape into another. The figures
5, 8, 10, 12 are some examples; fig. 3 exhibits a specimen, in which the beak has become
very large and wide. ‘Tihis is a rare case, as well as that seen in fig. 10; they are
extremes.

Another cause of variation is due to the punctuation and tubular spines ornamenting
the valves; their size, length, and number being rarely the same in many specimens ; at
times being so near to each other that one cannot perceive the intermediate punctuation
covering its surface ; in other specimens they are irregularly and sparmgly implanted, as
may be seen in the enlarged fig. 19, which appearance would seem to have induced
M. Buckman to propose one species for fig. 2, under the name of Sp. punctatus, and another
for fig. 1, by the name of Sp. reticulatus ; but in reality there is no difference between these
two specimens but in the size of the punctuation and spines, which are larger and stronger,
according to the size of the specimens. We also often perceive that much difference appears
to have been caused by local conditions; thus we have full grown adult specimens of three
lines in length and breadth, as well as in others of much greater dimensions; these form
varieties in the species, and we might name Spirifer verrucosus of Zieten as a mere dwarf
variety of Sp. rostratus.

The deltidium in this species is also very remarkable, being formed of two pieces united
in the form of a roof, which is well displayed in many specimens, especially in those found
in Normandy (Vieux pont), which I have represented in Pl. I, figs. 2,3,and 10; leaving
a passage above the umbo for the peduncular muscular fibres. When the deltidium is not
preserved, which is generally the case, the fissure is seen to extend to the extremity of the
beak. M. Deslongchamps, Bouchard, De Verneuil, and myself, have several specimens
illustrating these poimts in the most beautiful manner. On both sides of the deltidium
extends the area, which is well defined, dividing the beak on each side of the deltidium into
two equal portions, at once perceptible by the marked line extending from the extremity of the
beak along its whole length, at which line on both sides of the area the spines stop. The
remaining portion to the edge of the deltidium being covered by horizontal and vertical
lines of growth ; the vertical lines have not, however, much length or regularity, and are well

SPIRIFER. 23

represented in fig. 10, but not generally so much indented, in most cases they are scarcely
visible.

If we now separate completely the two valves, the interior will be seen as illustrated
by figs. 13 and 15. In the larger valve, fig. 15, we perceive, on each side of the deltideal
fissure, two teeth, which fit into corresponding sockets in the smaller valve, forming a strong
hinge, so that the valves cannot be separated except by breaking one of them; they are
placed at the extremity of two dental plates, projecting into the shell, forming the sides or
walls of the deltideal fissure, and extending to the beak, which they strengthen (figs. 15 and
16). Between the two dental plates, a central system is interposed, variable in thickness
and development, as may be seen in figs. 15, 16; beginning by a thick basis, which gradually
decreases till it becomes as sharp as the edge of a knife, and projecting far beyond the
lateral or dental plates (figs. 16, 21), two muscular impressions are visible between the
dental and central plate. The interior of both valves is closely punctuated.

From the discovery by Mr. Moore, of specimens completely freed from all matrix, in
which the most minute delicate impressions and details are preserved as intact as if the
animal had just left its shell, I am able to offer a much more complete description of the
small valve than that given in my paper published in the ‘London Geological Journal,’ (1845).
This valve, separated completely from the larger one, would appear as in fig. 13; we first notice
the dental sockets and position of the calcareous supports ; when both valves are united they
fill the greater portion of the larger valve, except where it covers the teeth and hinge, it will
be seen that two lamella issue from a strong basis under the sockets which extend, dimin-
ishing in width and thickness, till they reach about the middle of the shell, where a curved
lamellar process unites the two spires, but which process is rarely perceptible except when
the specimens are in a perfect state of preservation (figs. 16, 21); the two lamella again
continue to be directed toward the front of the shell, diverging from one another as they
advance, and finally turning towards the bottom of the large valve, forming the first and
successive coils, known under the name of spirals, each circle diminishing in circumference
and size as it approaches the sides of the shell. The spire has been, for Mr. Moore and
myself, the subject of active researches, and having found some specimens full of a very
fine sand, it was preserved in great perfection, and, as may be remembered, in 1847
I mentioned the presence of spines on the spire, but at that epoch we could not offer
observations as complete as at present. The lamella which forms the spire is neither smooth
nor of equal thickness on all its width, differing on each side and variable, but always thicker
on the imner side of the circumference than on the other which tapers out into an acute
edge, and as will be seen in figs. 17, 18, the thickest part of the spire is towards its middle,
where it forms a circular elevation diminishing again towards the outer edge.

It will be observed that no spines ever appear on the face of the lamella fronting the
sides of the shell, or on the internal edge of the spire, as is observed in figs. 17, 18; the
spines only occur in that part of the spire facing the front of the shell where it opens,
covering thus only about a quarter of the circumference of each coil. ‘These spines

24 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

arising from an expanded basis are also implanted very irregularly on this portion,
the calcareous matter of the lamella thickening sometimes and forming spines of
different length, sometimes isolated, at other times united in clusters of two, three, and
four, all directing themselves towards the exterior of the spire, and in general horizontally
to it, rarely exceeding in length the width of the lamella; but in some cases they are a
third longer, being of greater length and more numerous towards the centre of the spmose
portion: fig. 18 illustrates a correct and considerably magnified fragment of the spire.
Professor Owen thinks they are calcareous excresences destined to support the Cirri, and
in this view both Viscount D’Archiac and M. De Verneuil concur; the presence of these
spines only on that portion of the spine most exposed to currents, shows there was probably
greater strength and development of calcareous matter required in this portion of the spire.
‘The fact of the presence of spines, in a similar position, is common to many brachiopoda.
I have seen them in Spirifer rostratus, Walcotti Munstervi, Terebratula resupinata, Ter.
pectunculoides, &c., and in no specimens do they extend to the other portions of the spire.

The spirifer which Zieten considers to be Sowerby’s Spiri/er penguis, and figured
in his plate 38, fig. 5, is from the has of Vachengen, and seems only a variety of
Sp. rostratus, and has much resemblance to the variety figured in my Plate II, figs. 7, 8, 9:
However, the name of penguis would require to be dropped at any rate, because
Sowerby’s Sp. penguis is a Carboniferous shell, completely different from the Lias shell in
question ; M. D’Orbigny does not seem to have paid much attention to this point, as he
adopts the term penguis for a Lias shell. The Sp. rostratus has a wide range in the liasic
deposits, and has been found in the lower, middle, and upper lias, but chiefly in the marl-
stone of the middle Lias: fig..4 is the only specimen as yet found by Mr. Moore in the
upper Lias of Ilminster, and there exists no well authenticated instance of a Spirifer occurring
higher up in the series in England. ‘This species is found in many localities, such as Urn
Hill, Feavington, and South Petherton, near Ilminster, near Bath, Radstock, Cheltenham,
&c., and many fine specimens exist in several collections, especially that of Mr. Moore.
On the Continent it is also abundantly distributed; in many parts of France, particularly
in Normandy, near Caen, round Avalon, at Boll; in the Wurtemberg, near Amberg, in
the Canton of Basle, &. And M. De Verneuil has lately brought it from the province of
Ferusil (Spain) ; it is also found in America.

18. Sprrirer Inminsteriensis, Dav. 1851. Plate III, figs. 7, 7a.

Diagnosis. Shell imequivalved, rounded, mesial fold and sinus hardly perceptible ;
exterior of valves smooth, punctuated, and spinose; beak of large valve much produced,
projected backwards at right angles with the smaller valve ; area very large, triangular.
Length 2, breadth 3, depth 2 lines.

Obs. This little species was discovered by Mr. Moore, in the Leptzena or lowest beds

Sg ie a

SPIRIFER. 25.

of the upper lias, in the neighbourhood of Ilminster, and is found associated with Thecidea

rustica, Lept. Pearce: granulosa and a lingula, which was not sufficiently perfect to be
determined.

Plate III, fig. 7, represents a specimen of natural size, from the collection of
Mr. Moore; 7a is an enlarged illustration.

19. Sprrirer Watcorti, Sow. Plate III, figs. 2, 3.

Sprrirer Watcorti, Sow. 1823. Min. Con., vol. iv, p. 105, pl. 377, figs. 1, 2.

TEREBRATULA — Desh. 1836. Nouv. ed. de Lamarck, vol. vii, p. 374.
DELTHYRIS — V. Buch. 1840. Mém. Soc. Géol. de France, vol. iv, 1°* Série,
pl. 10, fig. 8.
SPIRIFER — Morris. Catalogue, 1843.
_ _ Deslongchamps. 1847. Soc. Lin. de Normandie.
TRIGONOTRATA — Bronn. 1847. Leth. Geog., pl. 18, fig. 14.
SPIRIFERINA — D’ Orb. 1849. Prodrome, vol. i, p. 221.

Diagnosis. Shell inequivalved, variable, with elevated mesial fold, and four lateral
rounded plaits; beak more or less recurved, area well defined, deltidium in two pieces,
hinge line shorter than the width of the shell; surface punctuated and spimose; spirals
and septum in the interior of both valves disposed as in Sp. rostratus, Dimensions vari-
able: length of the largest specimen known 19, width 24, depth 14 lines; but, m
general, the species does not attain that size.

Obs. ‘The species is easily distinguished from Sp. rostratus by its mesial fold, deep
sinus and plates. It was first discovered, many years ago, by Mr. Walcott, at Camerton,
about six miles from Bath, and represented by him in his work on petrifactions, fig, 33.
Sowerby also states that Mr. Walcott observed, of similar shells, ‘that those found on the
upper Bristol road, near Bath, are smaller, their shell thin, with a triangular hole between
the beak of the lower valve and the hinge, and have the body, fig. 38, a B, within them ;
it consists of two hollow cones, joined to each other by part of their basis, and to one of
the valves, but not so close as to prevent the animal, or part of it, from retreating into
them: their surfaces are beautifully covered with circular rows of small pyramids of spar.”
Thus, as Mr. Sowerby observes, in vol. iv. p. 106, of his ‘Min. Conch.,’ Mr. Walcott
was the first discoverer of the spiral appendages, long before they were used as a generic
character ; he also observed the triangular fissure, but did not understand the nature of the
spirals or their use, and it is but just, in treating of this species, to state, that on it those
important calcareous appendages were first noticed. It is a very variable shell, as may: be
seen in Plate III, figs. 2 and 3, is abundantly spread in the lower Lias, and more sparingly
in the middle Lias; it is common near Radstock and Bath. Fig. 2 illustrates the largest
specimen which I have observed, and which was found there by Mr. Moore ; it is also met
with in France, in Burgundy, and in many other localities on the Continent.

26 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

20. Sprrirer Monster, Dav. 1851. Plate III, figs. 4, 5, 6.

SPIRIFER OCTOPLICATUS, Zieten. (non Sow.) 1832. Die Verst. Wurttemb., pl. 38, fig. 6.
— — Dav. 1847. London Geol. Journal, pl. 18, figs. 11—14.
SPIRIFERINA — D’Orb. 1849. Prodrome, vol. i, p. 221.

Diagnosis. Shell mequivalved, variable, with elevated rounded mesial fold in small
valve, with corresponding sinus in larger one, with four, five, or six plaits on each side
of the mesial fold and sinus; beak more or less produced or recurved, elevated or
projected backwards; area well defined, with deltidium in two pieces; interior of both
valves similar to that seen in Sp. rostratus, Walcottii, &c.; surface punctuated and spinose.
Dimensions variable, the largest specimen known measuring—length 15, width 14 lines,
but commonly does not attain that size.

Obs. Many persons, as well as myself, have fallen into the error of attributing this
species to Spirifer octoplicatus, of Sow., M. C., vol. vi, table 562, figs. 2, 3, 4, 1829,
which name was given by that author to a Carboniferous species, much resembling our
Liasic one. Zieten appears to have principally led to this mistake, (Die Vers. Wurt.,
1832,) and it has also been referred by some Palzontologists to Spirifer acuticostatus, a
name given by Minster to a shell in the collection of Beyruth, and reproduced by Bronn,
along with many others, in 184.0, without description or figures, so that it is impossible to
say what shell was intended, and no species can be admitted on such uncertain grounds.
In 1844 this name, accompanied by a figure and description, was given by M. de Koninck
to a mountain limestone species, which name Bronn places first, in page 1172, of his
‘Index Palzontologicus.’ Spirifer Minsteri isa very variable shell, as may be seen from
three specimens in Plate III, and is found along with Sp. rostratus in the marlstone of
Ilminster, and in many localities abroad, such as Fontaine-étoupe-Four, near Caen, &c.
Plate III, fig. 4, illustrates the largest specimen I have seen, found by Mr. Moore, near
Ilminster; figs. 5 and 6 is the common state in which it occurs. It much resembles
Spirifer cristatus of the Permian deposits: the tubular spines which cover its surface are
stronger, and considerably more numerous, than those observable in Sp. rostratus. 'They
are also visible on the portion of the spine facing the front, as in the above-mentioned

species.

Genus—TEREBRATULA, Lhwyd. 1698.

Shell inequivalved, equilateral, more or less elongated, transverse or circular ; exterior
smooth, rarely striated or plicated; Zarger valve convex, except in Ter. Hugenii, where it
is depressed or slightly concave; with or without a sinus, corresponding to a mesial fold
in smaller valve, front straight or sinuated; beak straight or recurved and produced,

pk:

TEREBRATULA. 27

always truncated by an apicial, emarginate, or entire foramen, of a circular or elongated
shape, variable in its dimensions, and more or less separated from the umbo by a triangular
deltidium in one or two pieces, the foramen being surrounded by the substance of the
. larger valve and deltidium; no true area; lateral beak, ridges undistinct, short, recurved
to join the hinge margin, or continued along the sides of the shell without recurving, in
which last case there commonly exists between it and the hinge a flatness or false area.
Smaller or wmperforated valve convex or concave, with or without a longitudinal mesial
fold ; hinge composed of two teeth in the larger valve, which articulate with corresponding
sockets in smaller one, so that the valves cannot be separated without fracturing one of the
teeth ; internal ribbon-shaped lamella, (partly supporting the ciliated arms,) attached only
to crura, short or elongated, and more or less folded back on itself; animal fixed to sub-
marine bodies, by muscular fibres passing through the foramen, structure perforated.

Obds. It has been proposed to divide the genus Terebratula according to the length of
the loop, which will be referred to in our Introduction.

We have admitted forty species of British Oolitic Zerebratule, which can, we believe,
be conveniently retained, although, strictly speaking, many species pass one into another,
by some one or more common characters.

In the following table we have arranged these species into two sections, those with a
loop extending to near the frontal margin, and those in which the process does not attain,
or exceed, half the length of the shell; no external characters, however, seem to denote if
the loop be long or short, and we have placed a point of interrogation before those species
in which we have not actually seen it, but where, from observations or indication, we
believe it to be so.

Terebratula quadrifida.
— cornuta.
{ —— Edwardsil.

Beak laterally compressed, (ies Waterhoust

carinated; beak ridges ;

y j — resupinata,
continued along the sides | oa Nee
without recurving to join | :

3 : — __ impressa.
Ist Szcrion. the hinge margin; sur- ;
; = carinata.
Loop simply attached | face smooth. 1 gee nee
to crura, and extending i: wl Waltonii

to nea 2 ; ; :
ear the frontal — numismalis ; var. subnumismalis.

margin. a i
Beak uncompressed _late- ‘ ieliceiee
{ —_ digona,

rally; beak ridges soon
: Ae _ obovata.
becoming indistinct, or

i) ; — ornithocephala.
recurved to join the hinge wP
L — lagenalis.
margin ; surface smooth. :
“= sublagenalis,

Surface plicated, — cardium,

28 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

a subpunctata.

bie punctata.
_ indentata.

? — Buckmanii.
I Lycettii.
— insignis.
7 simplex.
7 ovoides.
2d SEcTION. — maxillata; var. submaxillata.
Beak uncompressed _late- Inc perovalis.

Loop simply attached rally, beak ridges soon be- 1 mr mnteraedine

to crura, and extending
to less than half the
length of the valves.

coming more or less in- = Phillipsii.
distinct; surface smooth = globata.
or incompletely plicated. = bucculenta.
| — spheeroidalis.
— globulina.

— pygmia.
2 — ~~ Bentleyii.

— coarctata.
— plicata.

| — fimbria.
— flabellum.

21. TEREBRATULA QUADRIFIDA, Lamarck. Plate III, figs. 8—10.

TEREBRATULA QUADRIFIDA, Lamarck. 1819. Anim. sans Vertebres, vol. vi, p. 35.

— — Deslongchamps. Soc. Lin. de Normandie, 1837.

— = V. Buch. Mém. Soc. Géol. de France, vol. iii, p. 190,
pl. xvii, fig. 3, 1838.

_ — Bronn. 1849. Index Paleont., p. 1247.

— — D’Orb. 1849. Prodrome, p. 240.

— — Dav. Annals and Mag. of Nat. Hist., vol. v, 2d Series,
pl. xiv, fig. 35. (Notes on an examination of Lamarck’s
Fossil Terebratule.)

Diagnosis. ‘ Testa triangulari-depressd, dilatatad levi superne quatuor angulis acutis
instructd, nati brevi.”” (Lamarck.)

Shell inequivalved, broader than long, irregularly pentagonal, depressed, variable ;
valves almost equally and slightly convex, with four rounded ridges, extending from the
umbo and beak to the front, and three corresponding sinuses on each valve; the hinge
margin is convex, extending to a considerable distance, and forming nearly half the
circumference of the shell, the remaining portion being well nigh equally divided into
three concave portions; beak small, with acute lateral ridge, continued along the side,
without recurving to join the hinge-margin, forming a well-defined marginal and false
area; beak slightly compressed, foramen entire and of moderate size, separated from the
umbo by an obtuse triangular deltidium in two pieces. Loop of imperforated valve simply

TEREBRATULA. 29

attached to the crura, and extending to near the internal frontal margin; impressions of
the posterior divisions of the valvular muscles strongly marked, valves minutely punctuated
and marked by numerous lines of growth. Dimensions variable, average length 14,
width 18, depth 7 lines.

Oés. This species appears to have been first described and named by Lamarck, it has been
long known as a characteristic liasic species, and, as is the case with most brachiopoda, it
varies considerably in shape, and, in my opinion, passes by insensible graduations into the
next form distinguished by Sowerby under the name of Zer. cornuta. Some specimens are
so irregular that one half would present the characters of guadrifida, while the other has those
of cornuta. In England the type forms of quadrifida, are much more rare than those of
cornuta, and seem to pass into each other’s type more than similar shells on the Continent,
and especially in Normandy, where both appear more distinct and permanent in their
character; therefore, to meet the wishes of the generality of Palzontologists, both names
are preserved, and the following may be given as distinctive characters. 7. cornuta is
deeper, more convex, and longer than it is wide, the reverse of what we generally find in
quadrifida, which is wider than it is long, flatter and much less deep, the beak and area are
also larger and more produced in 7. cornuta. Both species, or more properly speaking, in
my opinion, varieties of one type, they are found together in the same beds and localities,
but in some places one or the other form prevails. In Plate III will be seen illustrations
of both forms, as found in England; figs. 8, 9, 10 represent Yer. guadrifida, while
11—18 illustrates Zer. cornuta. Ter. quadrifida is usually found in the marlstone or
middle lias, and particularly at South Petherton, near Ilminster, where Mr. Moore pro-
cured many specimens, but I have not seen any as large or as fine as those of Normandy,
Vieuxpont, Landres, and Evrecy, near Caen; M. D’Orbigny states their occurrence at
Saint-Amand (Cher.), and Nancy, in France. Figs. 8—9 are from Mr. Moore’s collection.

22. TeresratuLa Cornura, Sow. Plate III, figs. 11—18.

TEREBRATULA CoRNUTA, Sow. Min. Conch., 1825, vol. v, p. 66, pl. 446, fig. 4.
= VICINALIS, V. Buch. 1838. Mem. Soc. Geol. de France, vol. iii, p. 192,
pl. xvii, fig. 5. (Non 7’. vicinalis, Schloth., according to
M. D’Orbigny.)
— cornuta, Morris. Catalogue, 1843.
— _— Bronn. 1849. Index Palzont., p. 1233.
— — D’Orb. Prodrome, 1849, vol. i, p. 240.

Diagnosis. Shell mequivalved, irregularly pentagonal, generally longer than wide ;
valves almost equally convex, thick and deep; hinge-margin forming nearly half the
circumference of the shell, the remaining portion and front being divided into three more
or less defined concave curves, the central or frontal one in common deeply indented, but
obscurely so laterally, the surface of both valves are smooth and shining; three concave
sinuses, forming two elevated rounded ridges, visibly diverging from the umbo towards

30 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

the front, but which only begin to rise above the level of the shell towards the anterior
portion, increasing as they approach the frontal margin; beak large, more or less
recurved, with lateral ridges continued along the side of the valve, without recurving, to
jom the hinge-margin, forming a defined marginal area; beak slightly compressed and
keeled, truncated by an entire foramen of moderate size; deltidium in two pieces, more or
less hid by the recurving of the beak ; loop free, attached merely to the crural base, and
extending to near the internal frontal margin; valves finely punctuated, and strongly
marked by numerous lines of growth. Dimensions and form variable, length 20, width
13, depth 12 lines.

Obs. When treating of Zer. quadrifida, I expressed how intimately I believed it was
connected with the present form, and stated what distinctions could be brought forward to
characterise both; it is a very common shell in the middle Lias, both of England and
France, found abundantly at South Petherton, and near Cheltenham, where it varies con-
siderably in form, as may be seen from the illustration, Plate III, figs. 17, 18. The
usual type approaching more or less to figs. 13, 16, and 21; 11, 14, 15 being exceptional
forms. ‘The largest specimen I have seen in England, measuring 21 lines in length and
18 in breadth, belongs to the collection of the British Museum. We are indebted to
Mr. Moore for the working out of the fine interior illustrating this species.

23. Terepratuta Epwarpsi, Dav. Plate VI, figs. 11, 13, 14, and 15?

Diagnosis. Shell inequivalved, globose, more or less circular, as wide as long, straight
in front; valves convex, sometimes globose, and distinctly emarginated; beak much
recurved, and truncated by a small foramen advancing over the umbo, almost touching it,
so as to conceal the deltidium, which is rarely visible ; lateral ridges extending along the
sides of the shell, without recurving to join the hinge margin; surface smooth, finely
punctuated; loop extending to near the margin of the shell, and simply attached to
Crura. Length 15, width 13, depth 10 lines.

Obs. ‘This species may be distinguished from both 7! punctata and subpunctata by
the shortness and squareness of its shape, as well as by its strongly recurved beak, lateral
ridges, smaller foramen, and length of loop, which last fact is due to Mr. Moore’s exertions,
who, after much trouble, was enabled to clear the process, seemingly identical with that of
T. cornuta, to which shell it approaches by many characters, though quite distinct by the
roundness of its sides and square front; in some specimens, as in 7. subpunctata, we
perceive a flatness at the umbo, see figs. 11 and 1la, due to compression when young.
Ter. Edwards is found along with Ter. subpunctata, cornuta resupinata, &c., in the marl-
stone of South Petherton, near Ilminster, and it gratifies me highly to name it after the
learned Dean of the French Academy of Sciences. It is with hesitation I have placed
here a solitary specimen, Plate VI, fig. 15, the shape of which is doubtless due to deformity.
Fig. 11, in Mr. Walton’s collection; 11—16, from that of Mr. Moore.

TEREBRATULA. 31

24, TEREBRATULA WateERHOUSII, Dav. Plate V, figs. 12, 13.

Diagnosis. Shell imequivalved, longer than wide; imperforated valve convex ; beak
small, rounded, and truncated by an entire foramen, with acute lateral ridges continued
along the sides, without recurving to join the hinge line; deltidium in two pieces ; imper-
forated valve convex, except towards the front, where there is a concave depression, distinctly
bent downwards, giving the frontal line an indented appearance; loop attached only to
the crura, and extending to near the frontal margin of the shell. Length 9, width 7,
depth 6 lines.

Oés. This species, although distinct, comes near to Zer. cornuta by the form of its
beak, approaching those varieties im which the lateral prominence is not developed; it
differs, however, in having the front distinctly bent downwards, as is seen in Plate V,
figs. 12a, 13a. Its greatest thickness is about the umbonal portion; it varies much in
form and shape, as may be perceived by comparing fig. 12 with fig. 13. Ter. Waterhousti
belongs to the upper portion of the middle Lias, and was first found by Mr. Walton and
myself at Farington Gurney, near Radstock, along with 7. xumismalis rimosa, &c.
Dr. Krantz, of Bonn, sent me specimens of this species from Bonfingen, in Wurtemberg,
in which locality this shell acquires larger dimensions than those as yet found in England.

25. TEREBRATULA RESUPINATA, Sow. Plate IV, figs. 1—5.

TEREBRATULA RESUPINATA, Sow. Min. Conch., 1818, vol. ii, p. 116, t. 150, figs. 3, 4.
— — Desh. 1836. Nouv. ed. de Lamarck, vol. vii, p. 360.
— = Pusch. Polens Paleontologie, 1837, tafal iv, fig. 6.
“= — Phillips. Geol. of Yorkshire, pl. xiii, fig. 23, 1835.
— a Deslongchamps. 1837. Soc. Linn. de Normandie.
—— — V. Buch. Mem. Soc. Géol. de France, 1838, p. 229,
pl. xx, fie. I].
— — Morris. Catalogue, 1843.
— — Bronn. Index Paleont., 1849, p. 1248.
— == D’Orb. Prodrome, 1849, vol. i, p. 239.

Diagnosis. Shell inequivalved, oblong, longer than broad ; rostral valve convex, much
compressed and keeled ; beak small and incurved, almost touching the umbo, lateral ridges
acute and continued along the side, without recurving to jom the hinge margin, false or
marginal area increasing in width at some distance from the beak ; foramen entire, remark-
ably small, with a wide obtuse deltidium, in two pieces, rapidly decreasing as it approaches
the small foramen, which it partly encircles. Imperforated valve, laterally convex, with a
deep central longitudinal groove and depression, extending from the umbo to the front,
which is considerably curved backwards and depressed. ‘The marginal line is straight or
gently curved on leaving the hinge, till it attains about two thirds of the length of the

32 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

shell, when, turning suddenly backwards by a rapid curve, it produces a considerable angle
to the first portion of the line and acute frontal depression.

Loop in smaller valve simply attached to the crura, and extending to near the frontal
margin; the inner side of the lamella, facing the opening of the valves, is regularly
covered with spines, similar to those observable on the spine of Sp. rostratus and loop of
Ter. pectunculoides, &c.; the outer side facing the sides of the valve is smooth, and always
without spines.

Valves smooth, finely punctuated, and marked by numerous lines of growth. Dimen-
sions and form variable; length 16, breadth 14, depth 12 lines.

Obs. Many shells have been attributed to Sowerby’s Jer. resupinata, apparently not
belonging to the type of that author, established on a liasic shell, answering to the above
description. It is, however, no easy matter, indeed scarcely possible, to give an accurate
description of any species agreeing with all the shells it includes, from the immumerable
variations they constantly present, especially in some species which pass into one another
in the most perplexing manner; so much so, that certain characters are diminished in
value from their irregularity. It is indispensable to give distinct names to certain forms,
which in reality merge from one type into another, but would be incomprehensible or
difficult to remember, if we were compelled to give a long and interminable list of varieties,
with distinct denominations added to the typical name. The Reswpinata group, for instance,
presents endless variety in form, most difficult to characterise, and especially so when we
have before us a great number of specimens. Sowerby’s type is distinguished from the
other members of the group by its small elevated and recurved beak, diminutive foramen,
and strongly laterally compressed and keeled rostral valve, more especially so towards the
beak, which character seems peculiar to some of the liasic species. The depression and
longitudinal groove of the imperforated valve, which is strongly marked in this form,
varies to so great a degree, that, on a large assemblage of specimens, we trace pas-
sages into the next species or variety, Zr. Moorez, where, instead of the depression
visible in the type Zer. resupinata, we find the imperforated valve completely convex and
gibbous ; so much so, that the longitudinal furrow disappears, and, becoming sensible only
towards the frontal portion ; the larger valve presents likewise a slight longitudinal depres-
sion towards the front, corresponding with that visible in the other valve, never seen in
Sowerby’s type of resupinata ; the margin line of the two valves is also nearly straight all
round, so that it would be difficult to recognise the original type of Zer. resupinata in
Ter. Moorei, had we not before us a number of specimens illustrating the gradual passage.
Ter. carinata, Ter. impressa, and other forms, which, though nearly allied and belonging
to the same group, should at least, for convenience, be considered as specifically distinct, as
they in general vary enough to be easily distinguished. It is to Mr. Moore we owe the
discovery of the first specimen, showing spines on the inner side of the calcareous loop,
facing the frontal opening of the shell, and which I subsequently recognised to be peculiar
to several species. er. resupinata is abundantly found in the marlstone beds of the

ee

TEREBRATULA. Be

middle Lias, associated with Zer. quadrifida, cornuta, Mooret, &c., at South Petherton, near
Ilminster ; at Deddington it was found by Mr. Faulkner, and is stated to occur in Yorkshire
by Professor Phillips. In France it is abundantly found at Evrecy, Landes, Fontaine-
étoupe-four, &., near Caen, and I believe also in Germany, though none of the numerous
specimens I have seen from’that country agree exactly with Sowerby’s type. Figs. 1 and 2
are from the collection of Mr. Moore.

26. Trerupratuta Mooret, Dav. Pl. IV. Figs. 6, 7.

TEREBRATULA Mooret, Dav. Bull. Soc. Géol. de France, 2° Série, t. vii., pl. 1,
figs. 21—23.

Diagnosis.—Shell ovate, elongated, slightly notched in front ; valves convex of a nearly
equal depth, smooth, finely punctuated, with strong lines of growth. The imperforated
valve presenting a slight longitudinal depression visible at the umbo, soon lost from the
convexity of the valves, but reappearing towards the front. Rostral valve convex with
small recurved beak, compressed laterally and keeled, with diminutive foramen ; a slightly
longitudinal depression is visible towards the front. The margin is straight, almost all
round. Loop simply attached to the Crura and extending to near the frontal margin.
Length 18, breadth 14, depth 11 lines.

Obs. When treating of Zer. resupinata we endeavoured to point out the affinities and
distinctive characters between the two forms. ‘This species is found in the marlstone of
South Petherton, along with 7. reswpinata. It also occurs in beds of the same age in
Normandy. Fig. 6 is from the collection of Mr. ‘Tennant.

27. TeREBRATULA ImpREsSA, V. Buch. PI. IV, figs. 8—10. PI. X, figs. 7, 7a 4 ¢.

TERABRATULA IMPRESSA, De Buch. Zieten Wiirtemb. Verst., p. 53, pl. xxxix, fig. 11,
1832.
— _ Bronn. 1837. Leth. Geog., p. 306, pl. xvii, fig. 12.
== — V. Buch. Mem. Soc. Géol. de France, 1** Série, p. 226,
pl. xx, fig. 7, 1838.
— -— Quenstedt. Das Flézgebirge Wurtembergs, 1843.
— Bronn. Index Palzont., 1849, p. 1238.
— — D Orb. Prodrome, vol. i, p. 288, 1849.

Diagnosis. Shell inequivalved, more or less rounded, length and width nearly the
same ; rostral valve convex with rounded recurved beak, foramen entire, deltidium in two
pieces obtusely triangular: lateral ridge of the beak continued along the side without re-
curving to join the hinge margin. Imperforated valve, slightly convex at the umbo; but
soon becoming gently and equally depressed; the marginal line of both valves forming a
regular depressed curve soon after leaving the hinge line. Loop simply attached to Crura

F

34 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

and extending to near the frontal margin of the valve. Surface finely punctuated ; length
and width from 9 to 10 lines, depth 5,

Oés. This species is generally distinguished from 7. resupinata and carinata by its
more circular form, the depression in the anterior portion of the smaller valve is less deep
and relatively broader, and more regularly curved ; the lateral ridges of the beak are not
extended so much in the longitudinal direction, the beak being rounder and not much
compressed. Such are the distinctions observable in well characterised specimens of Zer.
impressa found abundantly in the Oxford Clay of several parts of England, as at St. Ives,
in Huntingdonshire; and in similar beds near Boulogne-sur-mer. We also find in the
Inferior Oolitic beds of Cheltenham, a shell connecting Zer. cmpressa with 7. resupinata, but
which, from the size of its foramen and more circular shape, is more properly associated with
Ter. impressa ; and I perceive in the ‘ Prodrome,’ M. D’Orbigny places this last-named
species in the Inferior Oolite, or his Zerrain Bajocien, but omits it in the Oxford Clay, where
the type form of the species occurs. The similarity of some of the specimens from
Cheltenham to those of the Oxford Clay is so striking, that I would not even venture to
give this variety a distinctive name, as some specimens of Ter. zmpressa may be seen in
Pl. IV, fig. 9, to have a lengthened shape instead of a short circular form peculiar to the
generality of the impressa tribe. In Germany this shell is so abundant that local geologists
have distinguished the bed containing them by the name of Jimpressa-thorn : here likewise
we find a small difference in the aspect of the shell, which seems to me owing more to local
causes than to any specific differences. © These German shells are not commonly quite so
deep ; the smaller valve is a little less convex posteriorly than what is usually seen in those
from the Oxford Clay.

Another small race, or variety, Pl. X, fig. 7, is found in the Inferior Oolite of Sherborne,
Dorsetshire, which links Zer. resupinata to true 7. impressa; we place it with the last-
named species from the characters of its beak; as none of the species related to the
T. resupinata group, hitherto found in the Oolites, have that small laterally pinched and
recurved beak, or diminutive foramen so peculiar to the hasic species; a character any
one would perceive who had observed a series of specimens from the two deposits.
I have come to the above conclusion after a thorough examination of many hundreds of
specimens, nor should I think myself justified in distinguishing these varieties by distinct
names. |

Ter. impressa is abundantly found in Germany, especially in Wurtemberg.
Plate IV, figs. 9 and 10, are type specimens of the species from the Oxford clay, in
possession of Mr. Morris.
re fig. 8, var. from the Inferior Oolite of Cheltenham, from a specimen in Dr.
Wright’s Collection.
Plate X, fig. 7, a var. from the Inferior Oolite of Sherborne, in the Collection of the
British Museum.
u fig. 7a 4 c ave enlarged illustrations.

TEREBRATULA, 35

28. TEREBRATULA CARINATA, Lamarck. Plate IV, figs. 11—17.

TEREBRATULA CARINATA, Lamarck. Anim. sans. Vert., vol. vi, p. 25.
stioks — Tennant. 1847. Stratigraphical List of British Fossils, p. 73.
— _— Bronn. 1849, Index Paleont., p. 1232.
— — Dav. 1850. Lamarck’s Species of Fossil Terebratule, Ann.
and Mag. of Nat. Hist., vol. v, 2° Série, pl. xiii, fig. 25.

Diagnosis. “7. testé subquadrangulari levi ; valvd inferiori subcomplanatd superiore
diedraé medio-carinatd.’’—(Lamarck.)

Shell inequivalved, oblong, longer than wide, smooth, surface punctuated. Perforated
or rostral valve convex with slightly recurved beak, lateral ridges continued along the sides
without recurving to join the hinge margin, foramen of moderate size, entire and separated
from the umbo by a rather long deltidium in two pieces ; imperforated valve regularly and
gently compressed almost from the umbo ; front sometimes considerably thickened. ‘Loop
long and attached only to Crura: average dimensions; length 13, width 9, depth 5 or 6
lines, some specimens measuring, length 20, breadth 17, depth 10 lines.

Ods. This species, established by Lamarck, in 1819, is distinguished from 7. resupinata
by its rounder and less recurved beak, larger foramen generally separated from the umbo
by a greater distance and larger deltidium : it is also flatter and is a more elongated shell.
The depression of the imperforated valve is not the same in all specimens, some such as
those figured 13, 14, from Mr. Bowerbank’s Collection, are almost convex, presenting a
depression only towards the front. The thickening or emargination of the valves is very
great Im some specimens, as may be observed in fig 12, preserved in the Collection of
the Geological Survey. This species occurs in the Inferior Oolite near Stroud, Burton
Radstock, Dinnington, &c.; and fine specimens are to be seen in the Collections of Messrs.
Bowerbank, Morris, Moore, Walton, &c. In France it is found in the Inferior Oolite round
Caen in Normandy. In the Inferior Oolite of Chalford, near Stroud, and Crichley Hill, near
Cheltenham, a very wide and large variety of this species is found; figs. 15, 16, and 17,
remarkable from the size of its foramen; the lateral ridges are also much nearer to the
umbo and thrown off from the fore part of the beak openmg. I do not believe we could be
justified in separating this variety from Z. carinata, as the above distinctions are not per-
manent, but varying in many specimens. Of this variety many fine specimens are to be
seen in the British Museum, as well as in the Collections of Messrs. Morris, Buckman,
Dr. Wright, &c.

29. TEREBRATULA EMARGINATA, Sow. Plate IV, figs. 18S—21.

TEREBRATULA EMARGINATA, Sow. Min. Con., 1825, vol. v, p. 50, pl. 435, fig. 5.
_ — Deslongchamps. 1837. Soc. Linn. de Normandie.
_ _ Morris. 1843. Catalogue.
_ — Bronn. 1849. Index Paleont., p. 1236.
— — D’ Orb, 1849. Prodrome, vol. i, p. 287.

36 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Diagnosis. Shell inequivalved, subrhomboidal short and broad ; when adult notched
and indented in front, perforated valve convex, beak slightly recurved, foramen separated
from the umbo by a deltidium in two pieces, front defined by two angles or emarginate
edge, imperforated valve flat or slightly convex, sometimes depressed longitudinally towards
the front; smooth, punctuated and marked by strong lines of growth. Loop long, and
attached only to the Crura. Length 11, breadth 10, depth 6 lines.

Oés. The above description agrees with that given by Mr. Sowerby; it is a very
variable shell: the flatness of the imperforated valve seems to be one of its principal
characters. Some specimens are however slightly convex ; it approaches near to 7) carinata,
but is a shorter and wider shell, rarely presenting any of the longitudinal depression
common to Zer. resupinata and T'. carinata, forming one of the transition shapes connecting
the resupinata tribe, with a depressed imperforated valve to those species in which the same
valve is convex, such as Jer. Waltonii. In Pl. IV, figs. 18, 19, 20, I have given the
original specimens figured in the ‘ M. C.,’ kindly lent me by Mr. J. de C. Sowerby; fig. 21
belongs to Mr. Tennant’s Collection, and shows an unusual deep longitudial furrow.
This species belongs to the Inferior Oolite, and is stated to come from Nunney, near Frome.
Five specimens are preserved in the British Museum, collected by Mr. Cunnington. It
occurs also on the Continent, especially in Normandy, as noticed by M. Deslongchamps.

30. TrreBratuLA Warton, Dav. Plate V, figs. 1—3.

Diagnosis. Shell inequivalved, more or less oval; valves convex, beak produced,
rounded, truncated by an entire foramen, separated from the umbo by a rather long deltidium
in two pieces; lateral ridge of beak continued along the side, without recurving, to join
the hinge margin. ‘The margin line of valves nearly straight all round; front and sides
emarginate ; surface smooth, finely punctuated; very variable in form and dimensions :
with the same depth of 8 lines, the three specimens figured from the Collections of Messrs.
Walton and ‘Tennant gave a length of 18, 18, 13, breadth 11, 13, 11 lines.

Obs. This species is from the Inferior Oolite of Bathwick Hill, Bath and Burton.
The loop is unknown, but must have been simply attached to the Crura, and extended to
near the frontal margin. The emargination of most specimens of this species is very
remarkable, as well as the regular and almost equal convexity of the valves. It will take
place next to 7. emarginata, to which it is most nearly allied. I name it after Mr. Walton,
of Bath, who has kindly afforded me frequent assistance in this work.

31. TEREBRATULA NumismMALiIs, Lamarck. Plate V, figs. 4—9.
Var. Susyumismauis, Dav. Fig. 10.

TEREBRATULA NUMISMALIS, Lamarck. 1819. Anim., sans Vert., vol. vi, No. 22.
— COR, Valenciennes in Lamarck, 1819, An. sans Vert., vol. vi, No. 22.

TEREBRATULA. 37

TEREBRATULA NUMISMALIS, Zieten. 1832. Wiirtemb. Verst., pl. xxxix, fig. 4.
a ORBICULARIS, Zieten. 1832. Wiirtemb. Verst., pl. xxxix, fig. 5.
— NUMISMALIS, Bronn. Leth. Geog., pl. xviii, fig. &.
— -- Deslongchamps. 1837. Soc. Linn. de Normandie.
= — V. Buch. 1838. Mém. Soc. Géol. de France, vol. iii,
1*° Série, p. 191, pl. xvii, fig. 4.
- Bruyere. Ency. Meth., p. 240, fig. 1.
— Quenstedt. 1843. Das Flés. Wurt., pp. 183, 184.
= — D’Orb. Prodrome, vol. i, p. 240, 1849.
— — Dav. 1850. Lamarck’s Species, Annals and Mag. of Nat.
Hist., vol. v, 2% Série, pl. xiii, fig. 17, and pl. xv, fig. 22.

Diagnosis. “ T. testé subrotundé levi, utraque valvd superne sinu instructd: striis
concentricis remotis : nate brévi: foramine minimo.” —(Lamarck.)

Shell inequivalved, depressed, nearly circular or slightly pentagonal, notched in front,
variable in its contour; valves nearly equally convex, much depressed and flattened, surface
smooth, the margin of valves forming almost a straight line; beak slightly compressed
and keeled, lateral ridges of beak continued along the side, without recurving, to
join its margin; false area, very small and well defined; deltidium in two pieces, wide at
the umbo, diminishing as it reaches the foramen, which is entire and remarkably small.
Sometimes a slight central depression or sinus is visible on each valve; lines of growth
strongly marked, punctuation very fine. Loop free, attached only to the crural base, and
extending nearly the whole width of the shell; mesial plate well defined. Length and
width on an average nearly the same, from 11 to 13 lines, depth from 4 to 6.

Obs. This species was first brought into notice by Lamarck, who pointed out its
extremely small area and foramen ; it is easily distinguished from all other liasic and oolitic
Terebratule by its extreme flatness. Lamarck and Valencienne’s Zer. cor., as I stated in
the ‘ Annals of Natural History,’ of June, 1850, is a synonym of this species, established on
a specimen bearing accidentally the shape of a heart, and is only one of the numerous
variations in contour, observable in Zer. xwmismalis, as may be seen from some of the forms
illustrated in Plate ITI, figs. 4—9. This species is very abundant in the highest beds of
the middle and upper Lias, and it is only within a few years that it was discovered
in England, in the neighbourhood of Cheltenham, where the specimens have a dark
grayish colour. Mr. Walton and I found it two years ago in the neighbourhood of
Radstock, and at Farington Gurney, where they are yellowish, owing to the colour of the
clay in which they are imbedded ; and many fine specimens are to be seen in the Collections
of Dr. Wright, Professor Buckman, and others. It was also obtained by Mr. Hugh
Miller, from the Lias of Shendwich, in Scotland. Plate V, fig. 8, illustrates a specimen
from that locality. In France it is very common, about Eurecy, Landes, Vieux Pont,
St. Armand, Pouilly, Avallon, Lyon, &c., where larger and finer specimens than any
of our British ones have been found, and they may be viewed in the Collections of
M. Deslongchamps, of Caen, who kindly lent me the specimens illustrating the internal

38 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

loop, figured in Plate V, fig. 9. It is also abundant in Germany, and Von Buch gives the
following localities: on the Plienback, near Boll, near Hslingen, at Blattenhardt, Denchen-
dorff, Gonningen, and between ‘Tiibingen and Hechingen, at Eley, near Brunswick, &c.

Var. Susnumismauis. Fig. 10.

I have placed here, with some doubts, as a variety, the only specimens of a shell found
by Mr. Moore in the marlstone of Ilminster, from having observed, in the collection of the
Ecole de Mines, in Paris, specimens of undoubted xwmismalis, much approaching this in
shape. Its beak and foramen are, however, so much larger than that characteristic of true
numismalis, that, as is above stated, I am not certain of its*belonging to numismalis, but
do not like to make a species formed on the observation of a single specimen.

32. Terepratuta Baxrriz, Dav. Plate V, fig. 11.

Diagnosis. Shell mequivalved, broader than long; rostral valve moderately convex ;
beak small; lateral ridge rounded and indistinct; foramen entire, nearly touching the
umbo; imperforated valve less convex, with front rather suddenly bent downwards in the
middle, so as to present a semicircular figure; the frontal depression is continued along
the small valve to the centre, but becomes gradually shallower towards the umbo. Surface
smooth, finely punctuated. Length 4, breadth 5, depth 23 lines.

Oés. This little shell approaches in form to Zer. nucleata, but has not so incurved a
beak, and appears much less deep. Zer. Bakerie is stated to have been found in the
Inferior Oolite of Bugbrook, by the late Miss Baker, and is now preserved in the Collection
at the British Museum.

33. TEREBRATULA DIGONA, Sow. Plate V, figs. 18, 24.

TEREBRATULA DIGONA, Sow. Min. Con., 1812, vol. i, p. 217, tab. 96, figs. 1—5.
_ — Ency. Meth., pl. 240, fig. 5.
— — Lamarck. 1819. Anim. sans Vert., vol. vi, No. 19.
— — Deslongchamps. 1837. Soc. Linn. de Normandie.
— — Smith. Stratigraphical System of Organised Fossils, 1816, 1817.
— — V. Buch. 1838. Mém. Soc. Géol. de France, vol. iii, p. 194,
pl. xvii, fig. 6.
— — Morris. Catalogue, 1843.
— — Bronn. 1849. Index Paleont., p. 1235.
== —_ D Orb. 1849. Prodrome, vol. i, p. 315.

Diagnosis. Shell inequivalved, more or less triangular, oblong; valves convex ;

TEREBRATULA. 39

marginal line nearly straight, front more or less convex or concave, bounded, when old, by two
prominent angles alike in each valve, as if produced by the pinching of the edge; beak pro-
duced, rounded, truncated by an entire foramen, separated from the umbo by a somewhat
long triangular deltidium in two pieces; lateral ridges not continued to a great distance,
there existing a strongly-marked lateral flatness, the greatest width of the shell being
generally, though not always, at the front; surface smooth, finely punctuated; loop at-
tached only to the crura, and extending to near the margin of the shell. Dimensions and
form variable ; average size, length 13, width 9, depth 8 lines.

Ods. This is one of the first-described species in the Min. Con., and long known as a
characteristic oolitic fossil, and is stated by Sowerby, p. 217, to be “variable in its form,
sometimes almost globose, at others acutely triangular and rather depressed; the two
angles of the front are continued a little along each valve, and look as if they were
produced by pinching the edges between the fingers; the front between the angles is im
some shells concave, in others straight, or of different degrees of convexity.” Von Buch’s
description of this species would lead us to imagine that the greatest width of the shell
was always in front, since he states and underlines “ Les arétes Cardinales descendent en
divergeant d’une maniére continue vers les cotes, et remplacent tout a fait les arétes
laterales, on autrement dit ne convergent pas, mais descendent verticalement de sorte que
la largeur du front est en méme temps la plus grande largeur de la coquille.”’ Though
this is the general distinguishing character of digona, it often varies, as I have shown from
the original figures of the species, from Smith’s Collection, deposited, in 1816, in the
collection of the British Museum, thus often approaching, im general form and convexity,
to certain specimens of Zer. oovata, but in all its varieties 7. digona may be distinguished
by the lateral beak ridge not being recurved to join the hinge margin, and the lateral
angles at the front are never visible in obovata, the sides of the larger valve being in the
adult specimens usually flat and vertical, which is not the case in 7. obovata.

The figures I have given in Plate V will illustrate some of the varieties in form which are
presented by this species ; occasionally specimens are perfectly equilaterally triangular, others
are twice as long as they are wide, while some are as wide as they are long, and were well
figured and described by Mr. Smith, in 1816. It is a very common shell in the Bradford Clay
Forest Marble and Great Oolite ; it is found abundantly round Bath, Bradford, Cirencester,
&c., it occurs by millions at Ranville, in Normandy, and in other localities, and is also stated
to be found at Muggendorf, by Von Buch. Fig. 18 illustrates Mr. Smith’s specimens,
now in the Collection of the British Museum.

34. TEREBRATULA oBovaATA, Sow. PI. V, figs. 14—17.

TEREBRATULA OBOVATA, Sow. Min. Con., 1812, vol. i, p. 228, tab. 101, fig. 5.
— — Morris. Catalogue, 1843.
= — D’Orb, Prodrome, vol. i, p. 316, 1849.

40 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Diagnosis. Shell obovate, transverse, valves nearly equally convex, gibbous, beak more
or less recurved and rounded, foramen entire, with lateral ridges recurved and joining the
hinge margin within a short distance of the beak; deltidium in two pieces, more or
less visible, according as the beak becomes more or less recurved: front straight or slightly
convex, bounded by two obsolete plaits, sides rounded, margin rather flat, loop simply
attached to the Crura and extending to near the front margin. Dimensions variable, length
15, width 18, depth 10 lines.

Oés. This species was correctly described by Sowerby in 1812. It is a thick globose
shell, abundantly spread im the Cornbrash of many localities; as at Rushden, in
Northamptonshire, where it attains large dimensions, as may be seen from a suit of
specimens from that locality, presented to the British Museum by Mr. Waterhouse. It is
also abundant in Wiltshire, where specimens showing the loop to great perfection can be
obtained. It occurs near Scarborough, where it was obtained by Mr. Bean, and is likewise
found in many parts of the Continent; at Boulogne, by Mr. Bouchard. D. Bronn does
not appear to have been acquainted with this species, from what we find in the ‘ Index
Paleontologicus.’ Itis always more globose than 7. digona, and does not present any frontal
angles, its greatest width is also considerably increased towards the middle of its length.

Pl. V, fig. 16, illustrates one of the original specimens of the M. C.

14, 15, two full-grown specimens from the British Museum ; fig. 17 showing

a curious deformity in this species, in which the accident is reproduced

on both valves. .

Pl. VII, fig. 5, is a very curious shell found in the Cornbrash of Norman Cross, by
Mr. Morris, along with the true types of obovata and lagenalis ; after
minute comparisons, Mr. Morris and myself came to the conclusion that
it can only be a deformity of the species under consideration.

2)

35. TEREBRATULA ORNITHOCEPHALA, Sow. Plate VII, figs. 6, 13, and 23.

TEREBRATULA ORNITHOCEPHALA, Sow. 1812. Min. Con., vol. i, p. 227, tab. 101,
figs. 2, 3, 4.
— LAMPAS, Sow. 1812. Min. Con., vol. i, p. 228.
_ TRIQUETRA, Sow. 1825. » Min. Con., vol. v, p. 65, tab. 445, fig. 1.
— ORNITHOCEPHALA, Smith. 1816, 1817. Stratigraphical System of
Organised Fossils.
— — Desh. 1836. Nouv. Ed. de Lamarck, vol. vii, p. 361.
os — Phillips. 1836. Geol. of Yorksh., vol. i, tab. 6, fig. 7.
— —_ Zieten. 1832. Die vers. Wiirt., tab. xxxix, fig. 2.
— _ Morris. 1843. Catalogue of British Fossils.
_ Bronn. 1849. Index Palzont., p. 1243.
— —_ D’ Orb. 1849. Prodrome, vol. i, p. 316.
— SUBTRIQUETRA, D’Orb. 1849. Prodrome, vol. i, p. 216.

TEREBRATULA. 4]

Diagnosis. Shell ovate rhomboidal, depressed when young, elongated and gibbous when
adult ; beak rounded, much recurved and truncated by an entire foramen closely approach-
ing the umbo; deltidium in two pieces, more or less hid by the prominence of the beak,
without distinct lateral ridge; imperforated valve, most convex near the umbonal part
of the shell; when young sometimes slightly indented in front, most wide posteriorly ;
rather depressed laterally, and tapering more or less in front: surface smooth, finely punc-
tuated : loop simply attached to the crura and extending to near the frontal margin ; form
variable ; average size, length 16, width 11, depth 10 lines.

Obs. Several species have been established from varieties of the type under con-
sideration, but they merge into one another by insensible passages; we might probably
place among them Zer. Jagenalis, Schl., and ¢riquetra of Sow.; this last, especially, is only
a younger, wider and slightly indented state, as I became convinced from an examination
of the original specimens of the ‘M.C.’ lent me by Mr. J. De C. Sowerby, Pl. VII, figs.
10, 1l and 12, illustrating the original types of 7. triquetra. The principal difference I
perceive between 7. /agenalis and T. ornithocephala, is that in the last the posterior margin
of the shell is larger and more prominent, while in 7. /agenalis the lateral sides are much
straighter, and wider and more square in front. Prof. Brown in his ‘Index Palaontologicus’
places 7: Jagenalis among the Synonyms of ornthocephala; and M. Deshayes in 1836, while
describing Zer. Jagenalis, states that it has some analogy to ornithocephala ; but as several
Paleontologists seem desirous of retaining the name of 7. dayenalis for those more elongated,
thicker and straighter varieties, I have described both under a distinct head, and in PI.
VII will be seen a number of specimens illustrating both. Figures 6, 7, 8, 9, 10, 11, 12,
would represent the typical forms of ornzthocephala. The interior of both 7. ornitho-
cephala, fig. 23, and 7. Jagenalis are completely similar ; some varieties or rather specimens
of ornithocephala, though gibbous at the umbone, present a slight longitudinal depression
in that portion as seen in fig. 9. Zerebratula lampas of Sow. is merely an internal cast of
Ter. ornithocephala, and which M. D’Orbigny seems to adopt as a species, and gives it to
a Liasic shell, but which I believe has nothing to do with Sowerby’s type.

In England Zer. ornithocephala is found in the Kelloway Rock, at Kelloway, where
it was found by Messrs. Walton, Morris, &c.: it is abundant in the Fullers-earth all round
Bath; in the Cornbrash of Rushden, in Northamptonshire, where it was picked up by the
Rey. A. W. Griesbach, &c.; and may be seen in the Collection of the British Museum,
as well as in most collections. It is also found in many parts of the Continent.
Count A. De Zigno mentions it from the Venetian Alps; Zeiten and Quenstedt in Germany ;
and Deslongchamps from Normandy. PI. VII, figs. 7, 8, in British Museum; figs. 10, 11,
the original specimens of 7. ¢riguetra, in the Collection of Mr. J. De C. Sowerby ; fig. 23,
interior, from the Collection of Mr. Morris.

42 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

36. TEREBRATULA LAGENALIS, Schlotheim. Plate VII, figs. 1—4.

TEREBRATULITES LAGENALIS, Schl. 1820. Petrefacta.
TEREBRATULA — Desh. 1836. Nouv. Ed. de Lamarck, vol. vii.
= — De Buch. 1834. Mém. Soc. Geol. de Fr., vol. iii, p. 194,
pl. 18, fig. 7.
— — Tennant. 1847. A Stratigraphical List of British Fossils,
p- 73.
— _— Bronn. 1849. Index Paleont., p. 1240.

Diagnosis. Shell elongated, ovate, nearly straight in front; valves very convex and
gibbous; beak rounded and much recurved, truncated by an entire foramen, almost
touching the umbo; deltidium rarely visible, on account of the projection of the beak,
lateral ridges indistinct ; imperforated valve, gibbous and deepest near the umbo: posterior
margin rounded and extending by a gentle curve to the edge of the front, which is generally
straight ;:surface of valves smooth, finely punctuated. Loop simply attached to crura,
and extending to near the margin of the shell; central septum well defined ; dimensions
variable. Length 22, breadth 12, depth 11 lines.

Oés. As stated under the head of 7: ornithocephala, this species has very little to
distinguish it from the above-named shell, into which it seems to merge by insensible
passages ; it is therefore very variable, sometimes so much thickened in front, as to form
an almost flat surface, perpendicular to the surface of valve, as in fig. 1. At other times
it is on the contrary acute, as in fig. 2, and tapering almost into a sharp edge (fig. 4); the
beak is also more recurved than in 7. ornithocephala (fig. 1), but in some specimens, as in
fig. 2, the deltidium is completely exposed.

This species is abundant and finely preserved in the Cornbrash of Rushden, Norman
Cross, Undle, and Thorpe, in Northamptonshire, where it has been collected by the
Rev. A. W. Griesbach, Messrs. Waterhouse, Morris, and others. It has also been met
with by Messrs. Lowe and Walton, in the Fullers-earth near Bath, and from near Stamford,
in Lincolnshire. On the Continent it is abundantly distributed, and fine specimens, two
inches in length, have been obtained by M. Bouchard, from the Cornbrash of the neigh-
bourhood of Marquise (Pas de Calais). In Germany we meet it at Woschnau, at Grumbach
near Amberg, and near Scheffhausen, Wurtemberg.

37. TEREBRATULA SUBLAGINALIS, Dav. Plate VII, fig. 14.

Diagnosis. Shell inequivalved, oblong, valves convex, margin line nearly straight, front
indented and nearly as wide as the greatest width of shell; smaller valve convex in its
posterior portion, two rounded ridges rise soon after leaving the umbo and diverging
till they reach the lateral edges of the front, leaving a depressed concave portion or sinus
between them, extending and increasing in concavity as it approaches the front. Beak
rounded, without distinct lateral ridges, and truncated by an entire foramen of moderate

TEREBRATULA. 43

size ; deltidium in two pieces, surface smooth and punctuated ; margin line nearly straight
all round. Loop simple, attached only to crura and extending to near the frontal margin.
Length 15, width 8, depth 9 lines.

Ods. This species is found in the Cornbrash of Northamptonshire, is always accom-
panied by 2: dagenalis, of which it may perhaps only be a variety ; its great width in front
and deep longitudinal sinus, as well as the rounded ridges, which in both valves proceed
from the frontal edges to the centre of the umbo, seems to M. Bouchard sufficient reasons
for separating it from Lagenalis. Itis not, however, difficult to find specimens uniting orni-
thocephala to lagenalis, and this last to sublagenalis, but as the typical shapes of each are
well distinguishable, it will be found convenient to retain them under distinct specific names.

This last-described species is found in the Cornbrash of Northamptonshire, and of
Boulogne-sur-mer.

38. Teresratuta Carpium, Lamarck. Plate XII, figs. 13—18.

TEREBRATULA CARDIUM, Lam. 1819. Anim. sans Vert., vol. vi, No. 47. Figured in

Ency. Méthod., pl. 141, fig. 6.

— ORBICULARIS, Sow. 1829. Min. Con., vol. vi, p. 68, tab. 535, fig. 3.

— FuRcATA, Sow. 1829. Min. Con., vol. vi, p. 67, tab. 535, fig. 2.

— ORBICULARIS, Morris. 1843. Catalogue.

— oe V. Buch. 1838. Mém. Soc. Géol. de France, vol. iii, 1°"

Série, p. 160, pl. 16, fig. 3.

—_ CARDIUM, Deslongchamps. 1837. Soc. Linn. de Normandie.

— ORBICULARIS, Bronn. 1849. Index Paleont., p. 1243.

— — D’ Orb. 1849. Prodrome, p. 315.

— cARDIUM, Dav. 1850. Notes on an Examination of Lamarck’s Fossil
Terebratula. Annals and Mag. of Nat. Hist., June 1850.

Diagnosis. “ T. Testa elongato-ovatd, convexd, plicatd, sulcis longitudinalibus crassis
rotundatis: nati prominula.’ —(Lamarck.)

Shell imequivalved, more or less oval, elongated, uniformly convex; beak in larger
valve straight, truncated by a large entire foramen, separated from the umbo by a narrow
concave deltidium in two pieces; lateral ridges, indistinct valves regularly plaited,
variable in size, acute, bifurcated when young, and sometimes, though rarely, when adult ;
surface punctuated, loop long, attached simply to crura, and extending to near the frontal
margin. Length 16, width 12, depth 11 lines. |

Ods. This species was first figured by Bruyere, in the Ency. Méth., and described, in
1819, by Lamarck, under the name of Zer. cardiwm, which name must be preserved. In
1829 it was figured and described by Sowerby, under the name of 7. orbicularis, and the
young under that of 7’ furcata ; and it is singular to see that most authors (among whom
M. D’Orbigny) have made use of Sowerby’s name in preference to Lamarck’s, published
long before, and figured in the Ency. Méth., to which figure Lamarck refers. The size
and number of plaits in this species are very variable ; they are often few in number, wide

44 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

and strong; at other times numerous and more delicate, commencing at the umbo and
beak, becoming gradually and regularly wider as they approach the front; generally, in
the young state, the plaits are divided towards the margin, and while placing these into
another species, (Z. fwrcata,) Mr. Sowerby states, “it is therefore possible these may be
only young of ordicularis.” In adult specimens it is rare to see the plaits bifurcated,
but as a proof that it is sometimes so, we have figured Plate XII, fig. 15, a remarkable
specimen, found by M. Deslongchamps, wherein the plaits are once and even twice
divided; we are also indebted to M. Deslongchamps for the fine specimen illustrating the
loop. Professor King, in his ‘ Monograph of Permian Fossils,’ proposed to separate this
species from the genus Terebratula, under the generic title of Zudesia, but in the
Appendix seems disposed to cancel the genus, as it possesses all the characters of true
Terebratula. er. cardium does not vary to the extent of most species, and is always
recognisable ; it is found abundantly in the Great Oolite of Bath, Cirencester, &., and in
beds of similar age at Boulogne-sur-mer, Caen, &c.; it was never found in the Lias of
Weston, as stated by Mr. Sowerby, and subsequently by other authors, but it seems
confined to a narrow vertical range, and to be characteristic of the Great Oolite.

39. TereBraTuLa Buckmani, Dav. Plate VII, figs. 15, 16.

Diagnosis. Shell irregular, oval, longer than wide; valves convex, smooth, minutely
punctuated ; beak small, truncated by a large entire foramen, almost touching the umbo ;
deltidium small, concealed ; lateral ridges indistinct; margin line curved, rising in front.
Length 18, breadth 11, depth 8 lines.

Obs. This species occurs in the Inferior Oolite of Winchcombe, near Cheltenham,
where it was found by Professor Buckman, Dr. Wright, and others. It is quite distinct
from 7. ornithocephala by its shape, form of beak, foramen, and hinge marginal line of
valves. We likewise find in the smaller valve of some specimens a central longitudinal
elevation, extending from the umbo to the front, from which the two remaining lateral
portions of the valve recede rather abruptly, as may be seen in fig. 16. Pl. VII, figs. 15,
16, from Prof. Buckman’s Collection.

40. Teresratuta Lycerriu, Dav. Plate VII, figs. 17—22.

Diagnosis. Shell more or less circular; small, valves convex ; beak rounded, trun-
cated by an almost emarginate foramen ; the deltidium in two pieces, touching only in one
point above the umbo; lateral ridges indistinct; marginal line slightly curved; surface
smooth, finely punctuated. Length 8, width 7, depth 4 lines.

Oés. This small species was found by Mr. Moore in the upper Lias of Barrington,
near I!minster, where it abounds, and varies in size from 1 to 8 lines in length, but does
not appear to attain longer dimensions.

TEREBRATULA. 45

41. TEREBRATULA PuNCTATA, Sow. Plate VI, figs. 1—6.

TEREBRATULA PUNCTATA, Sow. Min. Con., 1812, vol. i, p. 46, tab. 15, fig. 4.
— — Morris. Catalogue, 1843.

Diagnosis. Shell imequivalved, depressed, convex; beak small, not much recurved,
truncated by an entire foramen of moderate size; deltidium in two pieces; beak ridge
soon lost ; margin line curved and slightly raised in front; surface smooth and minutely
punctuated ; loop short, attached only to crura, and extending to little more than a third
of the length of the valve. Length 16, width 12, depth 7 lines.

Obs. No species has perhaps given more trouble to make out than the one under
consideration, being difficult to characterise from its variations in form, particularly if we
examine a number of specimens. It seems nearly connected to the following form,
which we have separated, as it presents certain differences sufficiently constant to render it
desirable to preserve both under distinct names, and I do so the more readily, as it is also
the opinion of M. Bouchard, Mr. Moore, and others, who likewise examined the subject
with some attention ; nor am [astonished that foreign Paleeontologists have been unable to
recognise this species. Lamarck quotes it in 1819, but on the inspection of shells he had
placed under that name, I found none belonging to the species. Von Buch considered it
a synonym of ornithocephala; Professor Brown places it under both ornithocephala and
carnea (vide Index); and M. D’Orbigny, more cautiously, leaves it out entirely in his
‘Prodrome ;’ still it is quite distinct from either of the shells to which it has been considered
a synonym, which is perfectly proved by the size, length, and form of its loop, differmg com-
pletely from that of Zer. carnea, where it extends only to a few lines from the crura, while
in 7. ornithocephala it nearly reaches the frontal margin. In 7: punctata, as may be seen
(Plate VI, fig. 3,) from the specimen drawn from Mr. Sowerby’s original type, this process
extends to nearly half the length of the shell, and is intermediate between that of 7. carnea
and 7. ornithocephala, the beak and foramen being also quite different in those shells.
Ter. punctata is moreover a Liasic species, and, from its date, holds specifig claims of
priority, whatever shells may be grouped into its type or removed from it.

The name of 7. punctata was unappropriate, since all true Terebratulas are more or less
strongly punctuated ; it is, however, interesting to remark that this character was observed
so far back as 1812 by Mr. Sowerby. It belongs to the middle Lias, and is stated by that
author to have been found in the dark limestone of Aylesford, at a place called Horton ;
it was also collected in the Lias of Deddington, by Mr. C. Faulkner ; and at Dumbleton, near
Cheltenham, by Professor Buckman; it occurs at Farington, Gumey, and many other
places. Plate VI, figs. 1, 2, and 3, illustrate the original specimens, kindly lent me by
Mr. J. de C. Sowerby, which were figured in the ‘ Min, Con.’

46 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

42. TerepratuLa suspunctata, Dav. Plate VI, figs. 7—10, 12, 16?

Diagnosis, Shell inequivalved, ovular ; valves almost equally convex; beak rounded,
recurved, and truncated by a rather large entire foramen of an elongated shape, projecting
over the umbo, so as to conceal the triangular deltidium, in two pieces, existing under it, and
therefore rarely visible. The ridges of beak soon become indistinct ; marginal line slightly
curved and raised.in front ; surface smooth, punctuated ; loop attached only to crura, and
extending to about a little more than one third of the length of shell; the lamella is
strong and wide. Length 28, width 20, depth 17 lines, These are the dimensions of
the largest specimen known, but the average size is much less.

Oés. The different figures I have given in Plate V1 will show, to a certain degree,
the extent of variability observed in this shell, which is much deeper, stronger, and more
convex than in true 7! punctata ; it is, however, allied to that species, and many specimens
pass from one type into the other. The beak is less recurved, and deltidium more apparent,
in 7. punctata, its front bemg also more rounded. In many specimens of this species we
observe a well-defined flatness at the umbo ; it cannot be considered a character, but rather
a deformity, caused by pressure in the young state, retarding the normal and regular deve-
lopment of the shell, which is also shown by strong lines of growth. Fig. 8, and still
more fig. 12, illustrate how much such a malformation changes the general aspect of the
shell. Zer. subpunctata, which I have so named from its close affinity to punctata, is
abundantly distributed in the marlstone or middle Lias of South Petherton, near Ilminster,
and in other localities. On the Continent it was found by M. Deslongchamps and myself,
in the Liasic beds of Evrecy, &c. Along with the specimens found at South Petherton, by
Mr. Moore, was one (fig. 16) which I have been unable to place anywhere, except under the
head of a deformity of the shell under consideration, the form of its beak and foramen
being the same, and it has many visible marks of pressure upon it. Figs. 8, 10, 12, are
from the Collection of Mr. Moore.

43. TEREBRATULA INDENTATA, Sow. Plate V, figs. 25, 26.

TEREBRATULA INDENTATA, Sow. Min. Con., 1825, vol. v, p. 65, tab. 445.
— — Morris. Catalogue, 1843.
_ —_ Bronn. Index Paleont., 1849.

Diagnosis. Shell elleptical, longer than broad; valves nearly equally convex; beak
recurved, and truncated by an entire foramen; lateral ridges lost at a short distance
from the foramen, sometimes notched in front; surface smooth, punctuated ; loop short,
simply attached to the crura. Dimensions variable; size of largest specimen, as yet
observed,—length 14, width 10, depth 9 lines.

TEREBRATULA. A7

Ods. As Sowerby remarks, when describing this species, it sometimes shows little or
no marks of that indentation from which the name is derived; it is one of those species
which present some difficulties, not being as well characterised as we might wish, and
leading us, by gradual links, into Zer. punctata, with which it is generally associated. It
occurs in the middle Lias of Banbury, as stated by Mr. Sowerby; it was found also at
Deddington by Mr. C. Faulkner, where it is associated with Zer. resupinata. Itis common
at Farington, Gurney, &c. M. D’Orbigny erroneously considers this species as a synonym
of Zer. digona, (vide ‘ Prodrome,’ p. 315,) from which it is perfectly distinct, and belongs to
the Lias, and not to the Bath Oolite, as stated by that author. Its loop is short, extending
only to less than half the length of the shell, while in Digona it nearly reaches the frontal
margin of the shell. This species is also found on the Continent, but does not appear to
be known to the Palzontologists there. Figs. 25, 26, from the Collection of Mr. Walton.

44, TrrEBRATULA INsIGNIS, Schibler. Plate XIII, fig. 1.

TEREBRATULA INSIGNIS, Schiibler. Zieten, 1832. Die Verst. Wiirtembergs, pl. xl, fig. 1.
—_ — D’ Orb. 1849. Prodrome, vol. i, p. 376.
—_ — Quenstedt. 1843. Dos Flézgebirge Wiirtembergs, p. 484.

Diagnosis. Shell inequivalved, more or less oval, longer than wide; valves convex,
deepest towards the posterior portion ; beak produced, slightly recurved, and obliquely trun-
cated by a moderately-sized foramen, separated from the umbo by a rather long deltidium
tm one piece ; lateral ridges indistinct ; i smaller valve a well-defined mesial fold is seen to
extend to the front, with lateral depressions; larger valve regularly convex, no deep sinus
corresponding to the elevation in its smaller valve; surface smooth, punctuated ; loop
short, simply attached to crura, and extending to less than half the length of valve.
Length of our British specimen 20, breadth 15, depth 11 lines.

Oés. This remarkable Oolitic species has not before this been noticed in England ;
it occurs in the Oxford Clay of St. Ives, and in the Coralline Oolite of Malton. It
seems little known even to Continental Palezontologists. Yon Buch’ erroneously considers
it a synonym of 7. perovalis, and Dr. Bronn’ the same as Zer. diplicata, likewise a
mistake: it is perfectly distinct from both by its general appearance, and especially by its
deltidium formed of one piece instead of two, which is the case with both 7. perovalis and
biplicata. This species was well figured by Zieten in 1832, and correctly noticed by
M. D’Orbigny in his ‘ Prodrome ;’ he places it both in the Oxford Clay and Coralline Oolite.

1 Mem. Soc. Géol. de France, vol. ii, 1° Série, 1838.
? Index Palzeontologicus, vol. ii, p. 1239. Dr. Bronn’s synonyms of Ter. diplicata are far from being

correct, and it is evident that Sowerby’s species is little known.

48 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

It is not improbable, that the specimens attributed by Roémer' and Pusch’ to 7. perovalis
belongs to 7. cxsignis. .

Though small in England, in some continental localities it attaims very large dimen-
sions. I have specimens from the Coral Rag of Nattheim Wurtemberg, sent me by
H. Krantz, measuring 3 inches in length and 2 in breadth; it is found in many other
localities, such as in the Oxford Clay of Boulogne-sur-mer, where it was found by
M. Bouchard ; at Ecommoy (Sarthe), route de Gray, near Besancon; La Latte, Apremont
(Ain), in the Coralline Oolite of Chatel-Censori, Tonnerre (Yonne), &., and in many
German localities. ‘The specimen figured in my plate is from the collection of Mr. Bean,
of Scarborough, who found it at Malton.

45. TEREBRATULA SIMPLEX, Buckman. Plate VIII, figs. 1, 3.

TEREBRATULA SIMPLEX, Buckman. 1845. Geol. of Cheltenham, pl. vii, fig. 5.
— — Tennant. 1847. A Stratigraphical List of British Fossils, p. 74.

Diagnosis. Shell inequivalved, longer than broad ; larger valve convex; beak rounded,
recurved, and truncated by an entire foramen, thickly edged and concentrically furrowed,
advancing over the umbo, which is partly concealed, as well as the deltidium, which forms
a concave inward curve, transversally striated by minute lines; no distinct lateral ridge ;
imperforated valve, moderately convex, flat, or slightly concave, especially towards the
front; surface smooth, finely punctuated. Length 2 inches 4 lines, breadth 2 inches
1 line, depth 1 inch 5 lines.

Oés. This species, when young, seems to have its smaller valve flat, depressed,
nearly even; this is also seen in some old shells, (Plate VIII, fig. 2,) the junction of both
valves forming in front an acute angle, but in general, in adult specimens, such as
Plate VIII, fig. 1, the upper valve is convex, though never very gibbous, much thickened,
andemarginate. ‘This species is well characterised, but placed erroneously by M. D’Orbigny
as a synonym of Zer, /ata (Sowerby), with which it differs in shape, form of beak, del-
tidium, &c. Ter. simplex is found in the pea-grit bed of the Inferior Oolite of Crickley
and Leckhampton Hills, near Cheltenham and Minchinhampton, and fine specimens are
preserved in the British Museum, and in the Collections of Dr. Wright, Messrs. Lycett,
Morris, &c.; the largest specimens obtained as yet, fig. 1, is from the collection of the
Geological Society; figs. 2 and 3 were kindly lent me by Messrs. Buckman and Walton.

46. TEREBRATULA OvoIvEs, Sow. Plate VIII, figs. 4—9. ,
TEREBRATULA OVOIDES, Sow. 1812. Min. Con., vol.i, p. 227, tab. 100.

— LATA, Sow. 1812. Min. Con., vol. i, p. 227, tab. 100.

' Roémer. ‘Dei Versteinerungen des Norddeutschen Oolithen-Gebirges, tafel ii, fig. 3.
? Pusch. ‘Polens Paleontologie,’ tafel iv, fig. 8, and perhaps fig. 5.

TEREBRATULA. Ag

TEREBRATULA TRILINEATA, Young and Bird. 1828. Geol. of York., pl. viii, fig. 17.
ae ovorpEs, Young and Bird. 1828. Geology of Yorkshire, pl. viii, fig. 12.
= = Desh. 1836. Nouv. ed. de Lamarck, vol. vii, p. 361.
— — Morris. 1843. Catalogue, p. 135.
-— LATA, Morris. 1843. Catalogue, p. 134.
— TRILINEATA, Morris. 1843. Catalogue, p. 137.
== ovorpES, Bronn. 1849. Index Palzont., p. 1244.
— TRILINEATA, Bronn. 1849. Index Paleont., p. 1254.

Diagnosis. Shell ovate, elongated, valves moderately convex, beak prominent, sub-
carinated and truncated by a rather large entire foramen, without distinct lateral ridges,
deltidium well defined, in two pieces ; lateral margin of valves straight with rounded front;
surface smooth, punctuated, and marked by concentric lines of growth. Length 2 inches
2 lines; breadth 1 inch 10 lines; depth 11 lines.

Obs. This species seems little known and has given rise to much confusion, but
having obtained the loan of a great many specimens, referred to it from Messrs. Sowerby,
Bowerbank, Ripley, C. B. Rose, Bean, Morris, &c., and from different localities, 1 was
soon convinced that Sowerby’s Zer. ovoides was the same as his Zer. ata, which can be
perceived by the simple examination of Pl. 100, of the ‘Min. Con.,’ which is only a
wider and more depressed specimen of the same species, nor does Sowerby’s figures give
a very correct illustration ; it is also evident from a numerous suit of Young and Bird’s
Ter. trilineata kindly sent me by Mr. Ripley, of Whitby ; this species must be also placed
among the synonyms of 7. ovoides. These authors appear to have been only acquainted
with internal casts of these shells, since they state that the smaller valve is always marked
by three slender depressed lines diverging from the umbo, owing to which circumstance
they gave it the name of ¢rd/ineata; these said lines are due to the central septum and
muscular impressions, visible on the surface of internal casts of most species of Terebratula,
and therefore cannot be used as a character; they also allude to the difference observable
in width and length, as well as thickness, in this species; it is the case too in Zer. ovoides
and Jata of Sowerby, the pinched beak visible in many specimens, and especially in internal
casts, appears to be one of its characters.

In Pl. VIII, fig. 5, we have represented Sowerby’s Zer. ovoides; fig. 4, his Ter. lata;
and figs. 6--9, Young and Bird’s Zer. ¢rilineata, which, as I stated, belong all to one type;
and as Zer. ovoides, Sow. appears the most common form, I have selected it to represent the
species, which is variable in its shape and dimensions; it is a flattish shell, rarely very convex
or gibbose. M. Deshayes, in 1836, adopted the name of 7. ovozdes, and places data among
its synonyms. Its Geological range has not yet been quite satisfactorily established ;
probably it lived during different deposits of the Oolitic series. From the Inferior Oolite
of Robin Hood’s Bay, near Whitby upwards, Sowerby states his Zer. lata and Ovoides
occur in blocks, and sandstone containing green-sand, in alluvial deposits of gravel, frag-
ments of chalk, &c., in some parts of Suffolk. It is not, however, a Cretaceous, but

an Oolitic shell, as Mr. C. B. Rose admits, and in which opinion I entirely concur.
H

50 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

It is evident that Professor Bronn is in error, when placing Zer. perovalis, Sowerby, as
a synonym of Zr. Jata (see ‘Index Paleeontologicus’). Nor can I agree with M. D’Orbigny
in thinking 7%r. simplex to be a synonym of 7" /a¢a (Prodrome, p. 287).

A7. TEREBRATULA MAXILLATA, Sow. Plate IX, figs. 1—9.

TEREBRATULA MAXILLATA, Sow. 1825. Main. Con., p. 52, pl. 436, fig. 4.
— — Morris. Catalogue, 1843, p. 134.
-- Morris and Dav., 1847. Annals and Mag. of Nat. Hist.,
pl. xix, fie. 5.
= — D’ Orb. 1849. Prodrome, vol. i, p. 287.

Diagnosis. Shell subquadrangular, as broad as long, valves nearly equally convex,
beak produced, narrow, and strongly recurved ; foramen large, oblique ; deltidium obtusely
triangular; cardinal area slightly depressed, with obtuse lateral ridges; imperforated
valve with a mesial sinus, and two lateral ones corresponding to the lobes of the perforated
one, and which only extends one third inwards from the margin ; front strongly sinuated
in the young state, while for a considerable period of growth, no trace of smuated margin
is perceptible. Loop attached only to crura, extending to little more than one third of the
length of valves. Length 32, breadth 34, depth 18 lines.

Ods. This is a very variable shell both m form and size, it is well described by Sowerby
in ‘M.C.,’ who states it to be “ distinguished from Zer. intermedia by the depth of the
sinuses and consequent furrows which extended at least half way to the beak, mm some
specimens the two ridges between the furrows are very prominent and approach more
nearly together, than in the specimens figured; such shells are generally long shaped,
&c.” This species has been found to attain in some localities much larger dimensions than
those observed by Sowerby, who states it to be “always smaller than Zer. intermedia.”
In the ‘Annals and Mag. of Nat. Hist.,’ October 1847, Mr. Morris and myself had occasion
to notice some large specimens of this species found at Pickwick, which are figured in
Plate XIX of that periodical. Since that period, still larger specimens have been procured,
as may be seen in the Collection of the British Museum (Plate IX, fig. 4); and we have
been able to trace every size in this species, from that of a pin’s head to the larger specimens
just mentioned ; its greatest diameter is sometimes in the longitudinal, at other times in
the transverse direction; some varieties are with the same dimensions deeply plicated,
while others show no traces ; in the young state, and for a considerable period of growth,
there is no indication of plication, as may be seen by a glance at Plate IX, where we have
illustrated all these different states ; fig. 1 is the original form, considered by Sowerby as the
type of the species. Zer. mazillata is abundantly distributed throughout the Forest Marble,
the Bradford Clay, and the great Oolite round Bath, near Sapperton, and Hailey Wood,
about Cirencester, &c.; large specimens were found on the Continent, at Boulonge-sur-mer,
by M. Bouchard. Professor Bronn, in his ‘Index Palzontologicus,’ considers, erroneously,
this species a synonym of Zer. diplicata, thus placing together, under one head, a number

TEREBRATULA. 51

of different species. PI. IX, fig. 3, from the Collection of Mr. Morris; fig. 4, in British
Museum ; fig. 9, from the Collection of Mr. Bowerbank.

Var. SusmaxiLLaTa, Morris. Plate IX, figs. 10—12.

The shell which I here place as a variety of Zer. mawillata would appear to some
Paleontologists specifically different, but after a long and minute examination of a
considerable number of specimens, I came to the conclusion that the distinctive characters
were not sufficiently well defined or important to require it to be thus widely separated.
This variety is found in a light-yellow clay bed of the middle division of the Inferior Oolite
along with Zer. plicata, fimbria, and other well-characterised species. Var. submavillata
is more pentagonal in form than what we observe commonly in mawillata, the posterior
portion of the shell is straighter, tapering, and less circular than is generally seen in
Sowerby’s type; the young state, in both species and variety, is exactly similar.

Many fine specimens of this variety are preserved in the Collections of Dr. Wright,
Professor Buckmann, Messrs. Lycett, Morris, and others, who kindly forwarded to me these ~
specimens. Figs. 10 and 12, from the Collection of Prof. Buckman; fig. 11, from that
of Dr. Wright.

48, TEREBRATULA Prrovauis, Sow. Plate X, figs. 1, 6.

TEREBRATULA PEROVALIS, Sow. Min. Con., 1825, vol. v, p. 51, t. 436, figs. 2, 3.
— — Deslongchamps. 1837. Soc. Linn. de Normandie.
— — V. Buch. 1838. Mem. Soc. Géol. de France, vol. iii, 1°*
Serie, p. 221, pl. xx, fig. 2.
— — Morris. Catalogue, 1843, p. 135.
_ — Bronn. 1849. Index Paleeont., p. 1245.
— a D’Orb. 1849. Prodrome.

Diagnosis. Shell inequivalved, ovate, longer than wide, greatest width towards the
middle. Cardinal and lateral marginal line forming a gentle and regular uninterrupted
curve, with or without two more or less defined rounded ridges in frontal portion, hardly
perceptible in the adult state, where the sinus separating the two ridges is filled up by the
convexity of the valve extending to the frontal margin, and presenting one large elevation,
with two lateral sinuses more or less indented. Rostral valve convex, with depressions
corresponding to the elevations in the smaller valve ; beak rounded and truncated by a
large entire foramen, nearly touching and projecting over the umbo, generally concealing
the deltidium; lateral ridges indistinct, surface smooth and punctuated; loop simply
attached to crura, and short, extending to only about two fifths of the length of the valve.
Length 33, breadth 28, depth 23 lines; the average dimensions are much less.

Oés. ‘The original specimens described by Sowerby in the ‘ Min. Con.,’ and of which
I have given correct figures, Plate X, figs. 1,2, would hardly convey an idea of the species
under consideration, which varies considerably, as may be seen from the several illustrations

52 BRITISH OOLITIC AND LIASIC’ BRACHIOPODA.

offered in Plate X. Under favorable circumstances this species attained considerable
dimensions, and is the largest Oolitic brachiopoda with which we are acquainted. These
larger forms have been by some believed separable from 7. perovalis, and long known
under the name of 7. ovoidea, but as we can trace every stage of growth and variation, from
Sowerby’s type to the large specimens in the same beds and localities, it is evident
they must all belong to the same species, variable from the presence or nonpresence of
the two frontal ridges described above. The same has been observed relative to
7. mazxillata, where, wnder favorable circumstances, that as well as other species have
attained dimensions far exceeding those of the original type. We are indebted to that
excellent observer, M. Deslongchamps, for the knowledge of the internal loop of this, as well
as of other forms, worked out with the greatest skill and patience, we perceive that in
this as in most species where the loop is short, the lamella becomes much wider and
stronger than in those where the process extends to near the frontal ridge. 7! perovalis
is acommon and characteristic fossil of the Inferior Oolite, both in England and on the
Continent. The largest and finest specimens have been obtained from Dundry, Dinnington,
Yeovil, &., the best species being preserved in the Collections of the Bristol Institution,
British Museum, &c. Ter. perovalis is also very abundant in Normandy, where specimens
three inches in length have been procured, as may be seen in the Ecole des Mines of Paris,
and in the Collection of M. 'Tesson, of Caen, &c., and, although a well characterised
species, it has often been mistaken by many Geologists and Paleontologists, who refer to it
forms perfectly distinct, as may be seen by the synonyms given of it. Thus Von Buch
thinks Zer. cnsignis (Schiibl) to be a variation of this species, but from which it completely
differs, its deltidium being formed of one piece, while in 7. perovalis it is divided in two,
besides many other distinctions, which we shall notice under that species. Fig. 1, 2, from
the Collection of Mr. J. de C. Sowerby ; fig. 4, from that of Mr. Moore.

49. 'TEREBRATULA INTERMEDIA, Sow. Plate XI, figs. 1—5.

TEREBRATULA INTERMEDIA, Sow. 1812. Min. Con., vol. i, p. 48, tab. xv, fig. 8.

Diagnosis. Shell inequivalved, obtusely five-sided, longer than wide ; beak rounded,
recurved, and obliquely truncated by a rather large foramen, slightly overlaying the umbo,
and concealing the deltidium in two pieces; lateral ridges indistinct ; imperforated valve
less convex than the other, with (sometimes without) two rounded coste, commencing
about the middle, and continued to the margin, with a mesial furrow or sinus, and two
lateral ones; front margin moderately sinuated; surface smooth, punctuated ; loop short
and simply attached to crura, extending to less than half the length of the shell. Length
23, width 18, depth 13 lines.

Obs. Sowerby’s figures in the ‘Min. Con.’ do not illustrate this species in a satis-
factory manner, which has been the cause of many mistakes, as it is evident most authors
have not understood the shells intended as types, of which I became convinced from

TEREBRATULA. 53

inspecting the original specimens. Its exact stratigraphical age is the Cornbrash, as
distinctly stated by Sowerby, still we find it placed by Von Buch,’ Dr. Mantell,’ and
others, in the chalk; some state it to be from the Lias, Great Oolite, Oxford clay, &c.,
but it is singular few place it in its true stratigraphical position,* nor do I believe Zieten’s
figures referable to this species. er. cntermedia bears some resemblance to Zer. perovalis,
some specimens are indistinguishable; the common type differing, however, from the
Inferior Oolite specimens, in being wider and more regularly circular, especially towards
the beak and hinge margin: when young it is almost circular, without biplication, which
only appears at a more advanced age, and it may be remarked that it is impossible to
determine to what species some young shells belong, from the great resemblance they bear
to each other, specific distinctions only appearing at a more advanced period of growth.
The name of intermedia is well chosen, as its characters are intermediate, and lead us to
such shapes as Zer. Phillipsii and globata; from the first it is distinguished by its more
circular form, and from the last m being more depressed, and is a much larger shell.
Lamarck’s Jer. intermedia appears to be a Rhynchonella, otherwise his species could not
hold priority over Sowerby’s, published in 1802.*

Ter. intermedia is abundantly found in the Cornbrash of Stanton, in different parts of
Wiltshire, Rushden, &c., associated with Zer. lagenalis, obovata, Bentley, &e. Many fine
specimens are to be seen in the collection of the British Museum, and in the cabinets of many
collectors; it was found also by M. Bouchard in the neighbourhood of Boulogne-sur-mer.
Pl. XI, fig. 1, 3, in the Collection of Mr. Morris ; fig. 2, in that of Dr. Wright ; fig. 5, in
the British Museun.

50. Teresratuta Parisi, Morris. Plate XI, figs. 6—8.
- TEREBRATULA PHILLipsil, Morris. 1847. Annals and Mag. of Nat. Hist., p. 255,
pl. xviii, fig. 9.
— — D’ Orb. 1849. Prodrome, vol. i, p. 287.

Diagnosis. Shell elongated, irregularly pentagonal, posterior half of the shell and
beak tapering, truncated by an entire moderately large and rather oblique foramen, sepa-
rated from the umbo by a deltidium wider than high; lateral ridges obtuse and indistinct ;
large valve more convex than smaller one, with a somewhat incurved and produced beak ;
smaller valve with two rounded cost, commencing about the middle and continued to the
margin, with a broad deep mesial furrow or sinus, and two lateral ones; front deeply
sinuous, surface punctuated. Length 28, breadth 20, depth 13 lines.

1 Yon Buch. ‘Mém. Soc. Géol. de France,’ vol. iii, 1°° Serie, 1838, where it is placed as a synonyme
of Carnea.

2 Dr. Mantell. ‘ Fossils of South Downs.’

3 See D’Orbigny’s ‘ Prodrome ;’ Morris’s Catalogue, p. 133.

4 See Davidson’s Notes on an Examination of Lamarck’s Species of Fossil Terebratule, ‘Annals and
Mag. of Nat. Hist.,’ June 1850.

54 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Obs. This species, as stated by Mr. Morris in the ‘ Annals and Mag. Nat. Hist.,’ has
some resemblance to 7er. perovalis, Sowerby, but is easily recognised by its more elongated,
pentagonal, and depressed form, the greater width of the sinus and lobes, the more sinuated
front, and the greater prominence of the dorsal ridge ; it 1s also separated from 7. se//a, Sow.
by its elongated form, the greatest width bemg nearer the frontal margin than in that
species where it is central.

Ter. Phillipsii is from the Inferior Oolite of Dinnington, near Ilminster, Burton, near
Bridport, near Cheltenham, &c. On the Continent it is found. in Normandy, in beds of a
similar age. Messrs. Moore, Walton, Bunbury, Wright, Deslongchamps, and others,
possess fine specimens, and it is also to be seen in the collections of the British Museum
and Geological Survey.

51. TrereBratuLa GLopata, Sowerby. Plate XIII, figs. 2—7.

TEREBRATULA GLOBATA, Sow. 1825. Min. Con., p. 51, pl. 436, fig. 1.
— Kueintt, Morris, Desh., D’Orb., Bronn (non T. Kleinii, Lamarck).

Diagnosis. Shell subglobose, longer than wide ; beak rounded, recurved, and obliquely
truncated by a circular foramen of moderate size, almost touching the umbo, and concealing
the deltidium, which is small ; lateral ridges mdistinct ; smaller valve very convex at umbo,
with two rounded costa, commencing near and extending to the front, where they are
slightly produced, with mesial sinus and two lateral ones, corresponding to the elevations
in larger valve; margin of valves much sinuated ; surface smooth, finely punctuated ; loop
attached only to crura, and extending to less than half the length of the shell. Width 11,
length 13, depth 10 lines.

Obs. Most authors have attributed Sowerby’s Z\ globata to Ter. Kleinii of Lamarck ;
M. Deshayes, Morris, D’Orbigny, Bronn, &c. have fallen into the common error, but the
kind loan I received of the original collections of Lamarck and Sowerby has enabled me to
prove that both species were completely distinct.’ Zer, globata is one of those shells the
continual variations of which render it most difficult to describe. In Plate XIII, I have
endeavoured to illustrate a few of its varieties ; figs. 2 and 3 are drawn from Sowerby’s types,
and fig. 4, from the Inferior Oolite of Dundry, may likewise be considered a good represen-
tation of the species. In the Inferior Oolite of Leckhampton and Cotswold Hills, we find
a larger variety, which cannot be separated from 7. globata, figs. 5, 6,7; it is sometimes
almost circular, and at other times so much elongated as to appear to belong to another
form, we however find every passage connecting these extremes; another variety, also,
seems to occur in the Fullers Earth, round Bath, offering every possible variation of form
and convexity which we believe inseparable from the original type. Mr. Waterhouse and

1 See Davidson’s Notes of an Examination of Lamarck’s Species of Fossil Terebratula, ‘Annals and
Mag. of Nat. Hist.,’ June 1850.

TEREBRATULA. 55

myself took much trouble in minutely comparing a vast number of specimens, forwarded to
me from different quarters, with the types of Mr. Sowerby’s collection; we also compared
it with the origiual Zer. spheroidalis and 7. bullata, which some authors (Bronn, ‘ Jndez,’)
have considered synonyms of globata, while others (D’Orbigny, ‘ Prodrome,’) separate
T. spheroidalis, and place bullata as a synonym of globata; lastly, M. Deslongchamps
places 7. bullata and spheroidalis as synonyms, and separates globata. We are disposed
to adopt this view, and to consider 7’ dullata as a variation of spheroidalis. It possesses
more of the characters of this last than of g/odafa; its margin is scarcely sinuated, and
wants those defined costze and well-marked sinuses characteristic of the species under
consideration. It may be said that du//ata is a connecting link between glodata and
spheroidalis, but more nearly allied and more properly placed as a variation of the last-
named type.

Ter. globata is abundantly found in the Inferior Oolite of Dundry, Cheltenham,
Nunney, near Frome, &c., and fine specimens are preserved in the British Museum, that
of the Geological Survey, Bristol Museum, and collections of Messrs. Walton, Buckman,
Sowerby, and Dr. Wright. Pl. XIII, fig. 2, 3, from the Collection of Mr. J. de C.
Sowerby ; fig. 5, from that of Mr. Walton.

52. TEREBRATULA BUCCULENTA, Sowerby. Plate XIII, fig. 8.

TEREBRATULA BUCCULENTA, Sow. 1825. Min. Con., vol. v, p. 54, tab. 438, fig. 2.
— — D’ Orb. 1849. Prodrome, vol. i, p. 376; vol. ii, p. 24.
= = ? Zieten. 1832. Die Verst. Wurttemb., t. 39, fig. 6.
= — Deslongchamps. 1837. Soc. Lin. de Normandie.

Diagnosis. Shell inequivalved, elongated, irregularly oval; valves almost equally con-
vex; beak small, recurved, truncated by a small foramen almost touching the umbo, and
concealing the deltidium; lateral ridges indistinct; margin of valves almost straight,
front slightly produced, and laterally compressed or pinched; surface smooth and punctu-
ated. Length 13, width 12, depth 8 les.

Obs. Iam indebted to Mr. J. de C. Sowerby for the loan of the original specimens
illustrated in Plate XIII, fig. 8, obtained from Coralline Oolte or Calcareous Grit of
Malton, and, according to M. D’Orbigny,’ it would likewise occur in the Oxford clay, which
is not unlikely, as several species have been found in both deposits. Von Buch,’ Morris,’
Brown,‘ and others, believe it to be only a synonym of 7. dudlata, Sow., but I am not
prepared to admit the fact, as Z: ducculenta appears to differ from any true specimens of
Ter. bullata and spheroidals, a species peculiar to the Inferior Oolite of many localities.

1 D’Orbigny. ‘ Prodrome,’ 1849.

2 ¢Meém. Soc. Géol. de France,’ vol. iii, 1°" Série, 1838, p. 195.
3 Morris. Catalogue, 1843, p. 132.

4 Index Paleeontologicus, vol. ui, p. 1231.

56 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

58. 'TEREBRATULA SPHEROIDALIS, Sow. Plate XI, figs. 9, 19.

TEREBRATULA SPHHROIDALIS, Sow. 1825. Min. Con., vol. v, p. 49, tab. 435, fig. 3.

— BULLATA, Sow. 1825. Min. Con., vol. v, p. 49, tab. 435, fig. 4.

— — Deslongchamps. 1837. Soc. Lin. de Normandie.

~ SPHEROIDALIS, Deslongchamps. 1837. Soc. Lin. de Normandie.

— BULLATA, Desh. 1836. Nouv. ed. des Animaux sans Vert. de Lamarck,
vol. vii, p. 362.

= — VF. Buch. 1838. Mem. de la Soc. Géol. de France, vol. iii, 1°"
Serie, p. 195, pl. xviii, fig. 8.

= — Gieten. 1832. Dei Verst. Wurttemberg, tab. xl, fig. 6.

a SPHEZROIDALIS, Morris. 1843. Catalogue, p. 136.

— BULLATA, Morris. 1843. Catalogue, p. 132.

— — Bronn. 1849. Index Paleont., p. 1231 (but exclude all the
other synonyms given).

— SFHHROIDALIS, D’Orb. 1849. Prodrome, vol. i, p. 287.

Diagnosis. Shell inequivalved, more or less circular and spheroidal; beak small,
much recurved, and truncated by a moderately-sized circular foramen, almost touching and
advancing on the umbo; lateral ridges indistinct; margin lines of valves more or less
straight or curved, with or without a slightly sinuated front ; surface smooth and punctuated.
Loop short, attached simply to crura, and extending to about half the length of the valve ;
length 15, breadth 12, depth 12 lines.

Oés. From the study I have made of the original types of Sow., I believe 7. spheroi-
dalis and T. bullata both to belong to one species, and as 7. spheroidalis is the first
described, we have given it the preference ; but authors have not in general understood the
Sowerby type. Von Buch, while adopting 7. dullata, places 7. spheroidalis asa synonym
of globata. Prof. Bronn and M. D’Orbigny have also erred on this subject by placing
T. bullata and spheroidalis as synonyms of 7. Klein, Lamarck. TT. spheroidalis (as I
understand the species) is a very variable shell, some of its varieties differing much from
the common shape, but inseparable in my opinion; a few of these are illustrated in
Plate XI, showing it to be a more or less convex, globular, elongated, or flattened shell ;
figs. 9 and 19 are Sowerby’s types drawn from the original specimens, the first 7) sphe-
roidalis, the second 7. dudlata ; it will also be seen from figs. 9, 10, 12, 18, 15, 16, 18, and
19, that the frontal margin line of valves is in some straight (fig. 9), in others forming
either a convex or concave curve (in figs. 10, 14, 16, &c.), while in some differently
sinuated (figs. 12, 13), but not in general interrupting the regular convexity of the valves
in front. In some instances, nevertheless, as in fig. 19, two or more slightly produced
rounded cost proceed a little way from the front towards the umbo and beak ; leaving an
obscure furrow on each valve, but never as deeply biplicated as in 7. globata; this is an
exceptional character in the species under consideration. The internal loop is in all the
same, and we are much indebted to my friend M. Deslongchamps for having forwarded to

TEREBRATULA. 57

us perfectly worked out interiors of this shell. It attains considerable dimensions in some
localities ; the two largest specimens I am acquainted with are one in the British Museum,
and the other in the possession of M. Bouchard ; they resemble a billiard ball in form, mea-
suring 23 lines in length, 22 in breadth, and 21 in depth; our British specimens do not
attain these dimensions. In general, the convexity is regular from the umbo and. beak to
the front; but in some cases, after attaining certain dimensions, a temporary stoppage in
growth takes place, which, on being resumed, has caused the remaining portion of the shell
to deviate from the regular line, as in fig. 15. This is also the case in many specimens
which are smooth and regularly circular up to a certain period, but after a pause continue
their growth by giving birth to plaits or other ornaments, as we meet commonly in
T. fimbria plicata, &e.

The lines of growth are likewise more or less prominent in different specimens.

As stated by Sowerby, 7: spheroidalis is found in the Inferior Oolite of Dundry,
Nunney, near Frome, in different parts of Somersetshire, in Normandy, Bayeux, Curcy,
Monstiers, St. Maixant, as well as in Germany, and at Allen, Stuifenberg, &c.

54. TEREBRATULA GLOBULINA, Dav. Plate XI, figs. 20, 21.

Diagnosis. Shell inequivalve, globular, regularly convex, and gibbous; beak small,
scarcely prominent, recurved, and truncated by a diminutive foramen almost touching the
umbo ; lateral ridges distinct, recurving to join the hinge line; margin straight all round ;
valves almost equally convex, smooth, and punctated; loop short, attached only to crura ;
length 2, breadth 2, depth 1 line.

Obs. In 1847 I illustrated this small species,’ but I did not at that period think it
prudent to distinguish it by a specific denomination, as we believed it might only turn out
to be the young of some species; but from the great number of adult specimens found by
Mr. Moore, none of which exceed the dimensions above given, I have given to it the
name of globulina. It is found in the Upper Lias in the same bed that contains 7: pygmea,
Lept. Moorei, lasiana, Bouchard, &c., mm the neighbourhood of Uminster, and its dis-
covery is due to Mr. Moore, Fig. 20 natural size, fig. 21 enlarged.

55. TEREBRATULA PYGMEA, Morris. Plate XIII, 16, 16 a, 4, c.
TEREBRATULA PYGMEA, Morris. 1847. Annals and Mag. of Nat. Hist., vol, xx, pl. xix,
fie. 3, a, 0.
— — DOrb. 1849. Prodrome, vol. i, p. 221.
Diagnosis. Shell inequivalved, of a somewhat hexagonal form; valves convex, beak

1 Annals and Mag. of Nat. Hist., vol. xx, pl. xix, fig. 4.

58 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

small, recurved, and truncated by a diminutive foramen ; lateral ridges distinct, recurving
to join the hinge margin, with large longitudinal mesial fold in smaller valve, and cor-
responding sinus in larger one, and two lateral rounded plaits, with furrows corresponding
to these in the rostral valve; front deeply sinuous, the central simus by far the largest;
surface smooth, punctuated ; loop short ; length 2, width 2, depth 1 line.

Obs. This small species, described and figured in 1847 by Mr. Morris and myself, was
stated to come from the Lepteena bed of or above the marlstone in the neighbourhood of
Ilminster ; we do not, therefore, see why M. D’Orbigny places it in the Lower Lias or
his Zerrain sinémurien, where we do not find it. Since the period above alluded to,
it has been obtained from similar beds in the neighbourhood of Pic de Saint Loup, near
Montpellier, in France, along with Leptena hasiana by M. Bouchard, and also at Croisilles,
in Normandy, by M. Deslongchamps, though of the same dimensions as 7. glodulina,
it is easily distinguished by its sinuated front; we are also indebted to the researches of
Mr. Moore for the discovery of this species. Fig. 16, natural size, 16a, 6, ¢, enlarged
illustrations.

56. TurEBRATULA BentuEyi, Morris, WS. Plate XIII, figs. 9, 10, 11.

Diagnosis. Shell mequivalved, irregularly pentagonal, decussated, notched and sinuated
in front ; perforated valve convex, with two rounded coste proceeding from the extremity
of the beak, and regularly diverging to the front, separated by a deep medio-longitudinal
sinus, and two lateral ones ; beak keeled, recurved, produced, and obliquely truncated by
an elongated apicial foramen, separated from the umbo by a deltidium in two pieces;
lateral ridges well defined and continued along the sides without recurving to join the
hinge margin, leaving between it and the hinge line a somewhat flat false area. Smaller
valve slightly convex and depressed, subtrilobated, with three rounded costz, one central,
two lateral, divided by four grooves or sinuses proceeding from the umbo; the central
rounded plait rising only at some distance from the umbo, the others being larger and
more elevated than the central one ; surface smooth, punctuated, and marked by numerous
lines of growth. Length 16, width 18, depth 11 lines.

Obs. This is a very remarkable species not hitherto described, but found by the
Rey. A. W. Griesbach, Messrs. Bentley, Morris, and others, in the Cornbrash of Wallaston
and Rushden, in Northamptonshire, associated with 7. intermedia lagenalis, obovata, and
other well-known Cornbrash fossils, it has been met with in Lincolnshire, and I have it
likewise from France and Germany : it somewhat approaches in form to some specimens of
T. coarctata, but differs by many characters, especially by having its surface smooth, which
is not the case in the last-named species. We are not acquainted with its loop, but
judging from the external appearance of the shell would imagine it to be short, as in
T. coarctata. The two fine specimens illustrated in our plate belong to the Rev. A. W.

TEREBRATULA. 59

Griesbach and Mr. Morris; it is named after Mr. Bentley, at the request of Mr. Morris: a
fine specimen is to be seen in the collection of Mr. Lee. 7! Bentley: is a rare species,
at least in England, few specimens having been as yet discovered.

T. Bentiryr. Var. Sus-Bentiryi, Dav. Plate XIII, fig. 11.

We are indebted to Mr. Lycett for the discovery of the larger valve of a terebratula
which we believe to be only a well-marked variety of the above-described species, to which
it approaches by general character ; its shape, however, is more elongated, deeper, and the
medio-longitudinal sinus, in appearance, extends only to a short distance from the front ;
the lateral beak ridges are also less defined than in 7. Bentley:. Unfortunately we are
only acquainted with one of the valves of this shell, which may, perhaps, prove specifically
distinct when the other is obtained. Its stratigraphical position is likewise very different,
belonging to the Inferior Oolite of the neighbourhood of Minchinhampton, where it seems
rare; the dimensions are larger than those of 7. Bentleyi, measuring in length 22, in
breadth 18 lines. Fig. 11 is from the collection of Mr. Lycett.

57. 'TEREBRATULA COARCTATUS, Parkinson. Plate XII, Figs. 12—15.

TEREBRATULA COARCTATUS, Parkinson. 1811. Organic Remains, vol. iii, pl. xvi, fig. 5.
_ RETICULATA, Smith. 1816—1819, Strata identified by Organised Fossils,
p. 83, pl. xxx, fig. 10.
_ DECUSSATA, Lamarck. 1819. Anim. sans Vert., vol. vi, No. 51. Enc.
Meéthodique, t. 245, fig. 4.
— — Dav. Annals and Mag. of Nat. Hist., June 1850, pl. xiv, fig. 51.
TEREBRATULITES RETICULARIS, Schloth. 1820. Petref., vol. i, p. 269.
TEREBRATULA COARCTATA, Sow. 1823. Min. Con., vol. iv, p. 7, tab. 312, figs. 1—4,
— RETICULATA, Sow. 1823. Min. Con., vol. iv, p. 8, tab. 312, figs. 5—6.
— DECUSSATA and RETICULATA, Deslongchamps. 1837. Soc. Linn. de
Normandie.
— RETICULARIS, V. Buch. 1838. Mém. Soc. Géol. de France, vol. iii,
1° Série, p. 185, pl. xvii, fig. 7.
_— pDEcussaTA, Morris. 1843. Catalogue, p. 132.
— — Tennant. 1847. Stratigraphical List of British Fossils, p. 73.
— coaRCTATA, Bronn. 1849. Index Palzont., vol. ii, p. 1232.
— — D’ Orb. 1849. Prodrome, vol. i, p. 316.

Diagnosis. Shell imequivalved; subpentagonal, valves convex, sometimes gibbous,
hisped, decussated, and notched in front; perforated valve biplicated, with a more or less
deep angular sulcus between the plaits, extending from the extremity of beak to the front ;
beak moderately produced, truncated by a large entire circular foramen, separated from
the umbo by a more or less wide deltidium, often receding; beak ridges indistinct.
Smaller valve convex, subtrilobated with medio longitudinal plait; surface of valves covered
by a great number of short tubular spines, arranged longitudinally so as to form minute

60 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

elevated striz, intersected by transverse lines, giving the whole surface a reticulated
appearance ; structure punctuated, and marked by well-defined lines of growth.

Loop short, attached simply to crura, and not extending to half the length of the shell.
Length 12, width 11, depth 8 lines.

Oés. As may be perceived from the list of synonyms here given, this species has
received three principal names, indiscriminately made use of by various authors ; however,
that of 7. coarctata, established by Parkinson in 1811, appears the oldest and only one to
be retained, as 7. reticulata of Smith and decussata of Lamarck, are of a later period.

Mr. Sowerby, in 1823, proposed to retain both Z! coarctata and 7. reticulata, which he
thus characterises :—“ Ter. coarctata subpentagonal, gibbous, hisped, and decussated ;
lesser valves convex, subtrilobated ; larger valve biplicated, with a deep angular sulcus
between the plaits. Zer. reticulata obovate, gibbose, subhisped, decussated, front obscurely
three-sided, with a shallow channel between the ridges.” 7

These distinctions are not sufficiently constant to authorise the proposed separation, but
are simple variations seen so usually in almost every species; and in plate XIII we have
given illustrations of both varieties—fig. 12 representing Zer. coarctata, and fig. 15
T. reticulata, according to Mr. Sowerby; fig. 15 also exhibits a very unusual form of beak
in this species, which is strongly recurved, with the foramen almost touching the umbo.
The general character of the beak is much less recurved. ‘This species is likewise figured
by Mr. Walcot.’ The surface, or spinose strize ornamenting the surface, are very remarkable,
giving the shell a rough appearance; and, as may be seen from the enlarged fragments
(fig. 14), these short and thick spies arise from under each other along the elevated ridge;
they are rarely preserved intact, but rubbed down so as to give the shell a striated appear-
ance: their hollow tubular character is noticed by Mr. Sowerby. We are indebted to
M. Deslongchamps for the interior, showing the loop, which is short in this species.

Ter. coarctata is abundantly found in the Great Oolite, Forest Marble, and Bradford
Clay, all round Bath, Bradford, Hinton, Frome, &c., where it does not seem to exceed the
dimensions we have given: it is also a common species in beds of the same age on the
Continent, and especially round Caen, in Normandy. Fine specimens have, likewise, been
met with by M. Bouchard, near Boulogne-sur-mer. Mr. Walton informs me that he has
found this species in the Oxford Clay, but where it is very rare.

58. TerEBRATULA PLICATA, Buckman, 1845. Plate XII, figs. 1—5.

TEREBRATULA PLICATA, Buckman. 1845. Geol. of Cheltenham, pl. 7, fig. 6. (Non
Ter. plicata, Lamarck, 1849. An. sans Vert., vol. vi,
No. 39, which belongs to another genus.)
_ — Tennant. 1847. A Stratigraphical List of British Fossils, p. 74.
— SUBPLICATELLA, D’Orb. 1849. Prodrome, vol. i, p. 287.

1 Petrifactions found near Bath, No. 28.

TEREBRATULA. 61

Diagnosis. Shell inequivalved, elongated, oval, tapering posteriorly ; valves convex,
sometimes gibbous; beak small, not much recurved, truncated by a circular entire foramen,
deltidium small, receding; lateral ridges indistinct. Surface of valves smooth, up to a
certain age slightly undulating, or plaited towards the margin at a more advanced period.
Structure punctuated, loop short. Length 33, width 22, depth 17 lines.

Obs. The term plicata has been given by Lamarck, Borson, and Say, to different shells
placed by them in the genus Zerebratula, but which belonging to different genera are
only synonyms of other species; therefore, we think Mr. Buckman’s name, though of a
later date, may be retained, and that of Lamarck preserved for his species, which will have
to be placed in Fischer’s genus R/ynchonella. M. D’Orbigny proposes to change
Mr. Buckman’s name to that of Swéplicatella, which I would have readily adopted, but for
the reason above given. Ter. plicata is quite smooth up to a considerable age, when the
frontal and lateral edges become more or less undulated or plaited ; they never extend very
high up on the valves, but are restricted to near the edge, forming an irregular frill round
the shell, as seen in figs. 1 and 2. The plaiting in this species is very similar to that of
Ter. fimbria; but both species seem distinct. 7. fimbria is much smaller, rounder, and has
not got that tapering of the posterior portion, so peculiar to 7. plicata, which is likewise a
much larger shell.

Ter. plicata is found along with 7. fimbria in some of the beds in the Inferior Oolite,
in the neighbourhood of Cheltenham, Minchinhampton, &c., where many fine species have
been obtained by Dr. Wright and Messrs. Lycett, Buckman, Walton, Morris, and others ;
the three largest specimens with which we are acquainted may be seen in the collection of
the Geological Society and in those of Messrs. Morris and Buckman.

It has also been found at Tournus (Sadne et Loire), in France, by M. D’Orbigny.

Fig. 1 is from a specimen in the Collection of the Geol. Soc.; fig. 2 from the
collection of Professor Buckman ; fig. 5 from that of Dr. Wright.

59. TuREBRATULA FIMBRIA, Sowerby. Plate XII, figs. 6—12.

TEREBRATULA FIMBRIA, Sow. 1823. Min. Con., vol. iv, p. 27, tab. 326.
— _— Morris. Catalogue, 1843, p. 133.
—_ — Bronn. 1849. Index Palzont., vol. ii, p. 1236.
— — D’ Orb. Prodrome, vol. i, p. 287, 1849.

Diagnosis. Shell inequivalved, orbicular; beak short, slightly recurved, and truncated
by a circular foramen, almost touching the umbo, and generally concealing the deltidium ;
lateral ridges indistinct, valves almost equally convex, sometimes gibbous, smooth in the
young state, irregularly undulato-plaited at a more advanced age towards the margin ;
structure punctuated. Loop simply attached to crura, and extending to less than half the
length of the shell. Length 20, breadth 18, depth 13 lines.

62 BRITISH OOLITIC AND LIASIC BRACHIOPODA.

Obs. Sowerby’s figures of 7. fimdria illustrate only one of the states in which we
find this species ; nor does it appear to atta much larger dimensions than those given
above (fig. 6). In the young state, and sometimes up to a considerable period of growth,
the shell is quite smooth, without any plaits or ornaments, the margin line being straight
all round (fig. 11); but in some rare cases, even when young, the ornaments of its surface
are slightly perceptible (fig. 12); at a more advanced period the surface of the valves,
towards the edge, becomes irregularly undulated, much in the way of a frill, as stated by
Sowerby, but not extending to the hinge-margin, which is always smooth, and regularly
curved and rounded. Nothing can be more irregular than the manner in which these
ornaments are presented in different specimens, as may be perceived by the several illustra-
tions we have selected; at times, the whole surface of the valves is regularly rounded to
near the edge (figs. 6, 12); at other times, the smooth part is partially separated from
the plaited portion by a marked line of growth and a difference in level (figs. 2, 10),
proving that there was a sudden stoppage in growth, which, on being resumed, the shell
from smooth became undulated, or differently plaited. Sometimes, before the stoppage
alluded to, the shell had already become frilled, but on continuing the growth at a different
level these ornaments became differently disposed, having no continuity with the ones
already formed, as in fig. 10. These undulating plaits are also very irregular in their form,
im some cases a few small plaits are succeeded by a large one widely separated, others
close together: sometimes taking rise at about half the length of the valve, and, after
proceeding to some distance, separated into two or more bifurcations irregularly disposed
(figs. 7, 8).

The bifurcated plaits do not always reach the front, one or more disappearing at a
short distance from their origin, while some smaller plaits, at times, also appear between
the larger ones, so as to produce in that part of the shell a kind of irregular zig-zag
aspect.

Ter. fimbria is very abundant in certain beds of the Inferior Oolite in different parts of
Gloucestershire, near Cheltenham, Minchinhampton, &c., whence many fine series have
been obtained by Dr. Wright, Messrs. Buckman, Lycett, Walton, Morris, and others; it is
common in most collections. We have not yet observed this species in any of the Conti-
nental localities ; but it is probable future researches may lead to its discovery, since
T. plicata, a species closely allied to it, has been found in France by M. D’Orbigny.

Fig. 7 is from the collection of Professor Buckman ; fig. 8 from that of Dr. Wright.

60. TEREBRATULA FLABELLUM, Defrance. Plate XII, fig. 19—21.

TEREBRATULA FLABELLUM, Def. Dic. des Sciences Nat., vol. lili, p. 160, 1828.
— PALMETTA, Deslongchamps. 1837. Soc. Linn. de Normandie.
— FLABELLUM, Morris and Dav. Annals and Mag. of Nat. Hist., 1847,
p. 256, pl. xix, fig. 2.
_ PALMETTA, Bronn. 1849. Index Palzont, p. 1244.
— FLABELLUM, D’Orb. 1849. Prodrome, vol. i, p. 316.

TEREBRATELLA. 63

Diagnosis. Shell mequivalved, somewhat transversely oval, perforated valve, more
convex than the other, with a produced beak, truncated by a rather large circular foramen;
deltidium obtusely triangular, and in two pieces; cardinal or false area concave, nearly
smooth; valves costated ; seven or nine round costz imbricated, increasing in size, not in
number, towards the margin. ‘The central medio-longitudinal plait larger than the lateral
ones ; shell punctuated, marked by numerous lines of growth; loop short, simply attached
to crura, and extending to about half the length of the shell; dimensions variable.
Length 5, breadth 5, depth 3 lines; but some foreign species measure, length 6, width 8,
depth 4 lines.

Obs. This species seems to have been first described by M. Defrance, under the name
of 7. flabellum, but it is better known by that of 7: pa/metta to French Geologists ; and was
only within a few years noticed in England: it occurs in the Bradford Clay, of Bradford
and Corsham, Wilts, where it was found by Messrs. Walton, Pearce, and Waterhouse. In
France it is met with in the Oolite of Ranville, at Luc, and Langrune, near Caen, where it
attains very large dimensions; and I am indebted to my friend, M. Deslongchamps, for
working out the interior. This species belongs to the Zoricate of Von Buch, in which the
ribs of the smaller valve envelope those of the larger. Zer. flabellum is also remarkable for
its rare variability ; it is always easily recognised, being rather a scarce species, especially in
England. Figs. 20 and 21 of our plate are enlarged.

Genus—TEREBRATELLA, D’ Orb. 1847.

Diagnosis. Shell inequivalved, oval, sometimes transverse, larger valve more convex
than the smaller or imperforated one, which is in many cases flatter ; cardinal edge straight
or slightly curved ; a well-defined rather flat hinge area existing in larger valve, beak com-
monly straight and truncated by a foramen of an oval or irregularly triangular shape
placed more under than above the summit, formed out of a small portion of the substance
of the beak; cardinal area and triangular deltidium in two pieces, which are disunited in
many cases, the aperture bemg completed by a small portion of the umbo. Structure
punctuated, surface striated or plaited, often bifurcating; hinge articulating by means of
two teeth in larger and corresponding condyles in smaller valve. Loop generally long,
doubly attached, proceeding from the crura, but before attaiming its greater length it gives
off a flat, wide, more or less horizontal process, likewise attached to a central longitudinal
elevated septum, the principal lamella proceeding till it doubles itself m the shape of a
loop, as in true terebratulze.

Obs. We are only acquainted with one British Jurassic species attributable, according
to M. D’Orbigny, to this genus, viz. Zerebratella hemispherica, Sow.

64. BRITISH OOLITIC AND LIASIC BRACHIOPODA.

61. TEREBRATELLA HEMISPHERICA, Sow. Plate XIII, figs. 17, 18.

TEREBRATULA HEMISPHHRICA, Sow. 1829. Min. Con., vol. vi, p. 69, tab. 536, fig. 1.
— -_ = Deslongchamps. 1837. Soc. Linn. de Normandie.
— — Morris. 1843. Catalogue, p. 133.
— — Bronn. 1849. Index Paleont., p. 1238.
TEREBRATELLA — D’Orb. 1849. Prodrome, vol. i, p. 316.

Diagnosis. Shell inequivalved, hemispherical ; beak produced, recurved, truncated by
a large oval foramen placed more under than above the apex of the beak, encircled by a
portion of the extremity of the beak, cardinal area, disunited triangular deltidium, and
summit of the umbo of smaller valve, which is commonly quite, or nearly flat ; hinge line
slightly arched ; structure punctuated ; surface of valves ornamented by numerous small
longitudinal elevated striz: often bifurcating. Loop said to be doubly attached to crura
and to central longitudinal septum. Length 4, width 33, depth 2 lines.

Oés. Von Buch is in error when stating in his valuable Monograph of Terebratule
that this species is only a synonym of 7) gracilis, a cretaceous shell easily distinguishable
from 7. hemispherica; 1 shape and characters it is a well-defined species, varying less
than most oolitic shells; however, although its great and common character is to have an
almost flat imperforated valve, still in some specimens, and especially im many from
Normandy, this valve is more or less convex.

Notwithstanding my own and M. Deslongchamps’ endeavours we have not been able
to clear a specimen, so as to see the interior loop im a satisfactory manner, and therefore
have placed it in the present genus, more on M. D’Orbigny’s authority than our own, as
we consider a knowledge of the form and position of the process absolutely necessary to be
able to state positively to what genus or subgenus of the great family of Terebratulze each
species belongs.

Terebratella hemispherica is found in the Great Oolite of Hampton Cliff, near Bath,
and at Luc and Langrune, near Caen, in which last locality M. Deslongchamps obtained
some specimens larger than any hitherto found in England, where it does not seem to
exceed the dimensions above given. Fig. 17 natural size; fig. 18 are considerably
enlarged illustrations.

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PLATE si.

Fig
ie Lingula Beanii, P/c/., natural size.
la, 6. mi " interior of larger valve.
le, d. ss a * smaller valve.
2a, b. Orbicula Townshendi, Fordes, MS., natural size.
SE Orbicula Humphresiana, Sow., natural size.
3a, b. " = enlarged illustrations.
4.5.6.7. Crania antiquior, Je//y, natural size.
8, i a an enlarged illustration.
9. Crania Moorei, Dav., natural size. .
9a, b. nS 3% enlarged illustrations of the upper valve.
10. Thecidea Moorei, Dav., several specimens attached to Rhynchonella serrata.
NOG O60 eer bx - enlarged illustrations.
Lh. Thecidea triangularis, D’ Oré., natural size, from the Lias.
lla, 6. " ¥, enlarged figures.
12. s ss natural size, from the Inferior Oolite.
ba; Thecidea Mediterraneum, //sso, recent species, natural size.
14, Thecidea rustica, JZoore, MS., natural size.
14a, 6. a - enlarged representations of the exterior and
interior of the smaller valve.
15. Thecidea Bouchardii, Dav., natural size, from specimens found in the Lias
near Ilminster.
15a. ie > enlarged interior of attached valve.
‘t : enlarged illustrations of 72. Bouchardit.
18; Lepteena Moorei, Dav., natural size, Upper Lias, Ilminster.
18a, 6,¢,d,e. 5, os enlarged illustrations of exterior and interior of both
valves.
19. Leptzena Pearcei, Dav., natural size, from a specimen found in the Upper Lias.
19a, 6. " $3 enlarged illustrations.
20. Leptena granulosa, Dav., natural size, from the Upper Lias.
20a, b. 3 ss enlarged illustrations.
21. Lepteena liasiana, Bouchard, natural size.
21a. ne . enlarged figure.
22. Leptzna Bouchardii, Dav., natural size, from the Upper Lias, near Ilminster.
22a, b. Pe e enlarged illustration of exterior of both valves.
22¢. ms P = _ of interior of smaller valve.

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Fig.
Ue Spirifer rostratus, Sc//., the largest specimen known.
2. . J; from the Lias of Battle Down, near Cheltenham.
' Sp. punctatus (Buckman).

Ds Be Pr an unusual form of this species.

4, = a from a specimen found in the Upper Lias, near
Iiminster.

D. s A side view of a specimen from Ilminster.

6. 5 ‘ young shell.

Tc 35.9 % a: variety, with undulations, or rounded false plaits :
Spirifer pinguis of Zieten, non Sp. pinguis of
Sowerby.

10% U1, 22: s ke an unusual specimen.

13. es : interior of smaller valve, as it would appear on
separating the valves completely.

14. $3 % side view of a specimen illustrating the spirals.

15. Ps a interior of larger valve.

1G; % es enlarged illustration, showing the position and form
of the central septum and dental plates of
larger valve, relative to the spirals in smaller
valve; also the lamella, or cross-piece uniting
the two spirals.

ve . A enlarged illustration of a portion of the lamella,
facing the sides of the shell, showing that on
that side there are no spines.

18. A ‘, enlarged view of the inner side of the lamella of the
spirals, illustrating the manner in which the
spines are placed.

19. = ” magnified portion of the exterior of the shell, show-
ing the tubular spines and punctuation.

20. i‘ 3 enlarged fragment, showing the form and position of
the deltidium in two pieces.

21. x e magnified interior from a perfect specimen, In this

figure a part of the smaller valve has been
removed, so as to show the position of the
spirals and cross-piece uniting them, as well as
the relative position of the central septum of
the larger valve and the position of the spines
on the portion of the spirals facing the front of
the shell.

PLATE III.

Fig.
la, b Spirifer rostratus, Sc//., from the Lower Lias, near Cheltenham. Collection,
Buchman. This is only a variety of Spirifer
rostratus, described by V. Buch. and Zieten,
under the name of Sp. verrucosus.
le: - Fe enlarged fragment.
2. Spirifer Walcottii, Sow., the largest specimen with which I am acquainted,
from the Lower Lias of Camerton, near Bath.
Collection, Moore.
3. 4 a specimen from Radstock.
A. Spirifer Miinsterii, Dav., the largest specimen yet found in the marlstone
of Ilminster. Collection, Moore.
Aa. 7s Fs interior of larger valve magnified.
4d. 5 6 interior of smaller valve.
b, 6. - a two specimens from the same locality, illustrating
the common size.
re Spirifer minsteriensis, Dav., natural size, from a specimen found by
Mr. Moore in the Leptena bed _ of
Ilmininster.
7a. 5 6 enlarged illustration.
8. Terebratula quadrifida, Lamarck, from the marlstone of Ilminster. Col-
lection, Moore.
9. is : Collection of Mr. Moore.
10. 4 deformed specimen.
Le Terebratula cornuta, Sow., marlstone, Ilminster.
12. Pe x Collection of Mr. Moore.
13. . Z from a specimen in British Museum.
T4052 D607. ., a different specimens from Ilminster.
18. " ms perfect interior, showing the loop magnified.
18a. eA a side view.
180. ye . fragment, showing the crura and muscular im-

pressions.

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13, 14.
Tos 16.
L7.

18, 19, 20.

21.

Pail TB TV.

‘Terebratula resupinata, Sow., marlstone, Ilminster.
interior, showmg the loop and spies on its
inner side, facing the front.
<f A different specimens, from the marlstone of
Ilminster.
Terebratula Moorei, Dav., marlstone of Ilminster.
oe = from the same locality.
Terebratula impressa, V. Buch., from a specimen found in the Inferior Oolite
of Cheltenham: this forms a passage
from 7! resupinata into T. impressa.

Fe a; from the Oxford Clay of St. Ives.
Terebratula carinata, Zamarck, Inferior Oolite from near Stroud.
¢ re from a specimen in the collection of the
Geological Survey. 7
FA % two specimens.
. ‘ from the Inferior Oolite of Chalford.
. és young shell.

Terebratula emarginata, Sow., from the original specimens in the collection
of Mr. J. de C. Sowerby, Inferior Oolite.

- _ a malformation.

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Terebratula Waltonii, Dav., Inferior Oolite, Bath.

2? 3? 22 2)

. Terebratula numismalis, Zamarck, several specimens from the Lias near

Cheltenham and Farington Gurney.
f a5 a Scotch specimen.
eS Me interior, from the collection of M. Des-
longchamps.
56 ‘5 var. subnumismalis, from a specimen found by
Mr. Moore, in the marlstone of Ilminster.

Terebratula Bakeriz, Dav., Inferior Oolite, Bugbrook.
Terebratula Waterhousu, Dav., from the Lias of Farington Gurney.
Terebratula obovata, Sow., interior, from the Wiltshire Cornbrash.

* ya from the original specimen now in the collection

of Mr. J. de C. Sowerby.

$ . a deformed specimen.

‘Terebratula digona, Sow., the original specimen from Mr. Smith’s collection
in British Museum: Great Oolite, Bath.

- “ in British Museum.

és - interior, from the Bradford Clay of Cirencester.

9? 29 bp) 39

5 Fe a deformed specimen, in British Museum.

8 is from the Forest Marble, near Bath.
Terebratula indentata, Sow., two specimens from the Lias of Farington

Gurney, in Mr. Walton’s collection.

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OUR CMT eS ©

~

7, 8,9, 10. Terebratula subpunctata, Dav., from the marlstone of South Petherton.

1
12.
13, 14.
lb:
KG;

PLATE VL

Terebratula punctata, Sow., from the original specimens now in the collection
of Mr. J. de C. Sowerby.

93 ss interior, from the same collection.

03 : young shells, from Farmgton Gurney.

5 . from the Lias Shale of Dumbleton, near Chel-
tenham.

Terebratula Edwardsii, Dav., from the marlstone of Ilminster.
Terebratula subpunctata, a malformation.

Terebratula Edwardsu,

3)
x 4 ? from a malformation.

Terebratula subpunctata? from a malformation.

PLVL.

PLAT EB Vil.

Fig.

152: Terebratula lagenalis, Sc//., from the Cornbrash of Rushdon.
a x = interior.

A. ¥ Fe

5, Terebratula obovata, Sow., malformation, from the Cornbrash.

6, 7, 8, 9. Terebratula ornithocephala, Sow., from the Fullers Earth of Bath. 7.8, from
the Cornbrash of Rushden; in British

Museum.
40, 015 12,18. * be from Fullers Earth. 10, 11, are the
original specimens of 7) triquetra,
Sow., from Mr. J. de C. Sowerby’s

collection.
14. Terebratula sublagenalis, Dav., in British Museum’s collection.
15, 16, Terebratula Buckmanii, Dav., from the Inferior Oolite of Cheltenham.

17—22. Terebratula Lycettii, Dav., from the Upper Lias, near Ilminster.

oS. Terebratula ornithocephala, Sow., interior, from the Kelloway Rock.

Walton

LW.

Pointed by Hullman.

avidson del

T

: ae 7 = ‘os < m
a = ‘a

c=

ce at

- *

PRAT EH Vai

Fig.

1. ‘Terebratula simplex, Buchman. Inferior Oolite. In the collection of the Geol.
Society.

2. 3 BS

3 a » Young shell.

4. Terebratula ovoides, Sow. 7 lata, Sow.

D. z - T. ovoides, Sow.

65-7 Me > is a 7. trilineata, Young and Bird.

8. , " .

9.

% a From Whitby.

PLATE IX...

Terebratula maxillata, Sow. From the type of that author. Great Oolite, Bath.

22 >

if _ The largest specimen yet known; in the British
; Museum.

3 Young specimen, without sinuations, from Wiltshire.

% oh pee Young, from Hampton Chiff.

9 a Interior.

is Fe var. submaxillata, Worris. Inferior Oolite.

T.Davidson del ot ith

@

Muli it

Pi AT eax:

Terebratula perovalis, Sow. The origmal specimens now in Mr. J. de C.
Sowerby’s collection.

- - | From the Inferior Oolite, Dundry.
6 = From the Inferior Oolite of Dunnington.
_ 5 The largest specimen, I believe, yet found in
England.
» s Interior.
Terebratula impressa, De Buch. var. From the Inferior Oolite ; m the British
Museum.

Orbicula reflexa, Sow. From the Lias; in the British Museum.

Prmted by Hullmandel & Walton

T.Davideon del et bah

Terebratula intermedia, Sow.
39 33
bP) 2?

Terebratula Phillipsu, Morris.

29 39

Terebratula sphzeroidalis, Sow.

39 22
>? >?
29 9
3) 39
>? 9?
33 2)
32 3?

Terebratula globulina, Dav.

2 2?

Paar Xi.

Cornbrash.

Young shell, without biplication.

Interior, from specimens in the British Museum.

Inferior Oolite, Dinnington.

From Burton.

Young shell.

The type specimens in the collection of Mr. J. de C.

Sowerby, from the Inferior Oolite.

From the Inferior Oolite of Sherburn.

Interior.

A specimen illustrating the sinuous frontal margin
observable in some specimens.

Another specimen.

From the Inferior Oolite of Dundry.

A specimen, showing a cessation and resumed growth
visible in some specimens.

From the Inferior Oolite of Dinnington.

Inferior Oolite of Burton Radstock.

From the Inferior Oolite of Dinnington.

The original specimen of Zer. dullata, Sow., now in
the collection of Mr. J. de C. Sowerby.

Natural size, from the Lias of Ilminster.

Magnified illustration.

—

Fig.

Le; 17.
is.
19.
20.
21.

PLATE Xi

Terebratula plicata, Buckman. From the Inferior Oolite, in the collection of the
Geological Society, and in that of Mr. Morris.
These are the two largest specimens of the
species with which I am acquainted.

0 »9 Smooth specimens; the frill or plication appears
only at a more advanced age.

2) ?

Terebratula fimbria, Sow. From the Inferior Oolite. A very large specimen.

a 3 Interior.

Young specimen, quite smooth.
» 39 A young shell.
Terebratula cardium, Lamarck. From the Great Oolite, Bath.
From the Great Oolite, Bath.
A curious specimen, illustrating that, even some-
times at an advanced age, the plaits bifureate.
a - Young shell, plaits bifurcating. Zer. furcata, Sow.

»» is Interior.

Terebratula flabellum, Defrance. From the Bradford Clay, near Bradford.
3 Z Enlarged illustrations.
»» » Interior.

9.

10.
1 i

re.
Ho:
14,

15.
1G.

16a, ¢.

Ei.

Ls:
Ne.

Pil A Toe SET:

Terebratula insignis, Schuwbler, from the Coralline Oolite of Malton.
Terebratula globata, Sow., from the original specimens now in the collection
of Mr. J. de C. Sowerby: Inferior Oolite.

oy 5 Dundry.
ys G3 a curious variety from the Inferior Oolite of
Cheltenham.
9 = from Cheltenham.

Terebratula bucculenta, Sow. ‘The original specimen now in the collection
of Mr. J. de C. Sowerby — said to be
from the Coralline Oolite of Malton.

‘Terebratula Bentleyi, d/orris, MS., from the Cornbrash of Wallaston,
Northamptonshire.

2? 2? 2?

Terebratula Bentley, var. Sub-Bentleyi, Dav., from the Inferior Oolite of

Minchinhampton.
Terebratula coarctata, Parkinson, trom the Great Oolite of Bath.
99 a interior.
me Pe an enlarged fragment of the shell, showing
the spinose surface.
x N an unusual variety.
Terebratula pygmea, Morris, from the Lias of Ilminster.
33 = enlarged illustration.
Terebratella hemispheerica, Sow., natural size; Great Oolite, Hampton Chiff,
Bath.
F enlarged illustrations.

reader Dickensonii, Moore, MS., from the Inferior Oolite of Dinnington.

ited by Hullmandel 2 Walton f

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iran
a rn,

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ES 5,
dee re pe .

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