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“MEMOIRS

OF THE

GEOLOGICAL SURVEY

OF

THE UNITED KINGDOM.

BRITISH ORGANIC REMAINS.

DECADE I-¥\

PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY.

LONDON:

PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:

eo BY Bs

LONGMAN, BROWN, GREEN, AND LONGMANS.
1849. _

NOC hh.

PALZONTOLOGICAL researches forming so essential a part of geological
investigations, such as those now in progress by the Geological Survey
of the United Kingdom, the accompanying plates and descriptions of
British Fossils have been prepared as part of the Geological Memoirs.
They constitute a needful portion of the publications of the Geological
Survey, and are taken from specimens in the public collections, or lent
to the Survey by those anxious to advance this branch of the public
service. Although numerous drawings had previously been made, and
engravings from them considerably advanced, it was not thought expe-
dient to commence their publication until the large collections of the
Survey could be well examined, which a want of the needful space
has, until the present time, considerably retarded. This impediment

to progress is now being removed, and when the collections can be

properly displayed in the New Museum of Practical Geology, in

Jermyn Street, it is hoped that the public will have an opportunity
of gradually obtaining, in a convenient manner and at small cost, a
work illustrating some of the more important forms of animal and
vegetable life there preserved, and which have been entombed during

the lapse of geological time in the area occupied by the British islands.
The plan proposed to be followed in the work, of which the two
Decades now published form a part, is as follows :—

To figure in elaborate detail, as completely as possible, a selection of

fossils, illustrative of the genera and more remarkable species of all

1V NOTICE.

classes of animals and plants the remains of which are contained in
British rocks ; to select especially such as require an amount of illus-
tration which, to be carried out by private enterprise, would require
a large outlay of money, with little prospect of a return, and a long
time to accomplish, but which, by means of the staff and appliances _
necessarily employed on the Geological Survey, can be effected at small
cost, and with a rapidity demanded by the publication of the maps and
memoirs of the Survey; thus, it is hoped, affording an aid to those
engaged in the sciences with which this work is connected, that they
might not otherwise have possessed, and which may materially promote

the progress of individual research.

H. T. De ta Becug, |
Director-General. -

Geological Survey Office,
24th May, 1849.

BRITISH FOSSILS.

DECADE THE FIRST.

Tue first Decade of representations of British Fossils is devoted to a
selection of Echinoderms, of the Orders Astertade and Echinide.

With the exception of the Crinoidee and Cystidee, no special mono-
sraphs have been devoted to the illustration of our fossil species of
Echinodermata, notwithstanding their acknowledged importance in a
geological point of view. The majority of species found in British
strata are unfigured in British works; a very great number are not
figured at all, and those of which we possess British figures are, for

the most part, delineated either imperfectly or insufficiently for the

demands of science in its present state. This is the more remarkable
since, for the description and delineation of numerous species, ample
materials exist in collections.

Of the following plates, one is devoted to figures of all the Silurian
star-fishes as yet discovered in British strata. None of these have
hitherto been represented in any work. Their names only, accompanied
by short descriptive characters, have appeared in the ‘ Synopsis of
British Fossil Asteriadz,” contained in the second part of the second
volume of the “‘ Memoirs of the Geological Survey of Great Britain.”
Some remarkable new forms of star-fishes from the Oolites, and all as
yet discovered in the London clay, are figured in the second and third

- plates.

The fourth plate is devoted to a representation of the only fossil as
yet discovered of the family Huryales, now for the first time described
and figured, through the kind co-operation of the Rev. Professor

Sedowick,
b

vi BRITISH FOSSILS.

In the six following plates a series of illustrations of the British fossil
Fchinide is commenced, of the majority of which, even the commonest
and those most important for the identification of strata, no good repre-
sentations are accessible to the student of English fossils. ‘The import-
ance of a knowledge of the members of this family to the explorers of
oolitic and cretaceous strata cannot be too strongly insisted on, and their
beauty and interest, in a purely Natural History point of view, render
them admirable subjects for elaborate delineations.

When the collections accumulated during the course of the progress
of the Geological Survey have been thoroughly examined and arranged,
new light may be expected, bearing on the details of structure of the
species now figured. Additions will consequently be made to the plates
from time to time; and it is proposed to issue supplementary figures
of the variations of form exhibited by the several species selected as
subjects for these decades.

Epwarp Forses.

May, 1849.

DECADE ligt:

Geological Survey of the United Lingdom. URASTER |
> - ( Silurian ) .
a

®
>.
s

“SS

| URASTER RUTHVENI __ Forbes. 3) OSes ee ioe

G0 de PRES Oo POP hee. hee ae ee ee

BRITISH FOSSILS.

DecavEe I. Puate I.

—s

SILURIAN SPECIES OF URASTER.

[Genus URASTER. Agassiz. (Sub-kingdom Radiata. Class Echinodermata. Order
Asteriade. Family Urasteriea). Body stellate, five-rayed; a vent on the dorsal surface ;
rays rounded, surface spinous; ossicula small, compressed, irregular, reticularly combined ;
ambulacra bordered by three sets of spines; suckers quadriserial. The genera ASTERA-
CANTHION of MULLER and TroscHEL, and Astertas (restricted) of J. E. Gray, are
synonymous with URAsTER. |

Fie. 1.
URASTER RUTHVENI.

E. Forses, in “ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 463.

Draenosis. JU. brachits quinis teretibus, longissimis, angustis, subcari-
natis; disco parvo; pagind superiort reticulata, spinosa, spinis obtusis
fasciculatis. Ossiculis ambulacralibus linearibus, longis, geniculatis.

Description — Body very small, in the centre of five tapering linear
lanceolate, rounded rays, subcarinated on their upper surfaces, five
times as long as the disk is broad. The upper surfaces of both rays
and disk are reticulated, indicating a structure which originally in all
probability consisted of spines grouped in tufts. The under surfaces
are marked by the impressions of a double series of ambulacral articu-
lations, each slightly curved. Both these structures are present in
some existing antarctic forms of Uraster. The largest specimen
examined measured three inches and a half across, from arm-tip to
arm-tip.

Affinities.—The slender lanceolate arms distinguish this species from
any of its paleozoic allies as yet described. In general form it re-
.sembles some living species.

Locality and Geological Position—This interesting starfish was dis-
covered by Mr. John Ruthven, in strata of the Ludlow division of
Silurian rocks at Scalthwaiterigg, and also at Highthorns, both near
Kendal, in Westmoreland. Professor Sedgwick, in whose collection it

is contained, kindly communicated the specimen for description and
delineation.

(it i. | B

2 BRITISH FOSSILS.

Fic. 2a. (upper side) and &. (under side).
URASTER PRIMZAVUS.

E. Forses, in ‘ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 463.

Diaenosts. JU. brachiis quinis, brevibus, triangularibus, acuminatis ;
disco lato. Pagind superiori tuberculatd, reticulataé (spinosd? spinis obtusis
fasciculatis 2?) ossiculis ambulacralibus oblongis, latis, geniculatis.

Description.—Body very broad, pentagonal, produced at the angles —
into five short lanceolate or elongato-triangular pointed arms, which
are each about two-thirds as long as the breadth of the disk. Surface
of the disk convex above, as well as the arms tuberculated and reticu-
lated, exhibiting traces of having been covered by tufts of short blunt
spines. Madreporiform plate sub-central, as well as vent. Beneath
nearly flat, the interambulacral spaces reticulated like the upper surface,
the ambulacra composed of broad, oblong, geniculated plates, of which
there are about twenty in arow. ‘The largest specimens examined had
attained the dimensions of an inch and a half in diameter, measuring
from arm-tip to arm-tip.

Affinities—The general shape of this species reminds us of Asterina,
but its structure is so similar to that of the next fossil to be described, —
that I do not doubt it was a true Uraster. The pointed rays distin-
guish it at sight from U. obtusus, its nearest ally.

Locality and Geological Position— First found by Mr. John Ruthven,
in the Silurian (Ludlow) rocks at Underbarrow, near Kendal. It occurs
in a thin sub-calcareous band, loaded with encrinites and. trilobites, all
rare in the overlying sandstones. Numerous specimens have been col-
lected by Professor Sedgwick and Mr. Daniel Sharpe, both of whom
have communicated them for examination and delineation.

Peeve!
URASTER OBTUSUS.

E. Forses, in ‘‘ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 463.

Draenosis. WU. brachiis quinis, brevibus, convexis, lanceolatis, obtusis ;
longitudine brachiarum ad latitudinem disci ut 1:14, ossiculis ambu-—
lacralibus oblongis, latis, interstitiis linearibus; pagina superiori reticulato-
spinosa.

Description.—Body rather broad (being broader than the arms are
long), convex above, spinosely reticulate; the spines were short, and
probably grouped in tufts. The arms are short, convex above, broad,

-

BRITISH FOSSILS. 2

oblong, and obtuse. ‘Their under surfaces exhibit oblong, rather broad,
ambulacral plates, gradually decreasing in size towards the tips of the
arms, but nearly equal for about two-thirds of their length. The
-ambulacral sulcus between them is rather broad. The largest specimen
examined measured an inch and a half across.

Affinities —The contour of this fossil star-fish strikingly reminds us of
_ that of the living Uraster hispidus, but the structure of its dermal cover-

ing was very different. With no fossil as yet discovered can it be
confounded.

Locality and Geological Position.—First found in lower Silurian rocks,
at Drumcannon, near Waterford, in 1846, by Sir Henry De la Beche,
Captain James, R.E., and the describer; since by Mr. Gibbs, of the
Geological Survey, in Bala rocks, at Moei y Garnedd, near Bala, North
Wales. In the Inish locality it was associated with Phacops Jamesii and.
numerous Orthides. In the Welsh with Orthides, Trilobites of the
genera Asaphus and Homalonotus, and numerous stems of Encrinites.

hie, 4—
URASTER HIRUDO.

E. Forses, ‘‘ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 464.

Draenosis. UW. brachiis quinis, lineari-lanceolatis, acuminatis, disco
minuto; pagind superiori reticulata, decussata (spinis fasciculatis, fasciculis
spinarum seriebus longitudinalibus dispositis) ossiculis ambulacralibus ob-
longis, ambulacris latis.

Description.—Body very minute, about a fourth as broad as the rays
are long; rays tapering and linear-lanceolate, contracted at their bases,
pointed at their extremities. Their upper surface clothed with bundles
of spines arranged in very regular rows, and so placed that each ray
seems to be marked by three or four longitudinal furrows, crossed at
regular intervals by transverse grooves. Under surface with short
ambulacral plates and broad avenues. ‘The largest specimens do not
measure more than an inch across.

Affinities.—Unlike any fossil star-fish with which I am acquainted,
and possibly not a member of this genus.

Locality and Geological Position.—Gregarious in Silurian (Ludlow)
rocks at Pottersfell, near Kendal, in Westmoreland ; first found by
_ Mr. John Ruthven, and communicated by Professor Sedgwick. Its
aspect reminds us of Ophiura.

a BRITISH FOSSILS.

The materials afforded by the specimens hitherto procured of Silurian
star-fishes are too imperfect to admit of more extended descriptions than
those here given. They are sufficient, however, to enable us to pro-
nounce with confidence on the tribe, and even genus, to which they have
belonged, and to assert, without hesitation, that the several species
described are distinct from one another. ‘They are very interesting,
inasmuch as they exhibit the earliest forms of the order Asteriade.
Until within very few years past, it was supposed to have no paleozoic
representatives ; instead of which we now find them in the oldest fossili- —
ferous strata. On the Continent palzozoic star-fishes have hitherto been
noticed only in France, and much higher in the series of rocks than those
now figured. In North America several forms have been found, appa-
rently nearly allied to our own, and in rocks of silurian age. The genus
to which I have referred these Silurian star-fishes is one of the most
cosmopolitan of all the groups of the order, having representatives at
present in arctic and antarctic, tropical and temperate, seas; the indi-
viduals are perhaps most abundant in northern regions. Some of the
species have a considerable bathymetrical range.

E. Fores.
April, 1849. :

oy)

DECADE Pl.2.

Geological Surbep of the United Kingdom. ASTROPECTEN _
: g (Oolitic )

| ASTROPECTEN nastineta_ Forbes.

2D Lapeer Sas PHILLIPSIt Forbes .

Ci. Boe & J Phillips del* E. Forbes direx* ; IW.Lowry te.

BRITISH FOSSILS,

DecaveE [. Purare II.

es

OOLITIC SPECIES OF ASTROPECTEN.

[Genus ASTROPECTEN. Linck. (Sub-kingdom Radiata. Class Echinodermata. Order
Asteriade. Family Asteriz.) Body stellate, few (five) rayed; no vent; rays flat on both
sides, regular. Surface of body and upper sides of arms covered with paxille. Ambu-
lacra with two rows of suckers, bordered by spines. Margins of the arms bordered by a
double row of conspicuous plates.—The genera STeELLARIA of Narpo, and ASTERIAS
(restricted) of AGassiz, are synonymous. |

Prue. '.
ASTROPECTEN HASTINGIZ.

3

E. Forses, in ‘ Memoirs of the Geological Survey of Great Britain,’

vol. ii. part 2, p. 478. “
s

Draenosis. A. radiis brevibus, lanceolatis, acutis, lateribus rectis, angulis

intermediis obtusis ; ossiculis marginalibus quadratis, subequalibus.

Description.—Rays short in proportion to the rather broad flat body,
triangularly lanceolate, with very straight sides and pointed extremities.
The angles formed by their junction with each other and the body are
obtuse. Their margins are bordered by regular series of nearly equal
square plates, decreasing but slightly as they approach the apex. The
length of each ray is about equal to the diameter of the disk. There
are about 18 marginal plates in each row. ‘The surface is covered by
quadrate tessellations, indicating the arrangement of the plates, which
probably, when the animal was alive, bore tufts of paxillee or coronated
spines. ‘The specimen measures two inches in diameter.

Affinities —The Astropecten Philhipsii is probably its nearest fossil
ally, but the form and characters of its surface distinguish it con-
spicuously from any other British member of its genus.

Locality and Geological Position.—From oolitic beds (MARLSTONE) in
Yorkshire, precise locality not known. In the cabinet of the Mar-
chioness of Hastings, who has kindlv communicated it for description
and delineation.

ft. is. 2

2 BRITISH FOSSILS.

PxG.: 2:
ASTROPECTEN PHILLIPSII.

E. Forses, in “ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 478.

Diagnosis. A. radiis lanceolatis, lateribus rectis, angulis intermediis
valde obtusis ; ossiculis marginalibus oblongo-quadratis, spiniferis.

Description.— Disk moderately developed, the arms being in length,
compared with its diameter, as one and three-quarters to one. Rays
slender, lanceolate, forming very obtuse angles at the junction with each
other and the body. Margins of the rays bordered with oblong qua-
drate plates, which are studded with small tubercles, probably marking
the points of attachment of paxille ; on their edges also are a few
scattered lmear-lanceolate spines, which are not equal to the breadth of
the plate. ‘The ambulacra are bordered with semicircular combs of
short spines. The plates composing the skeleton of the body appear to
have been oblong. ‘The marginal plates at the angles are narrow, as
compared with those of the ray-borders. ‘The diameter of the body is
about an inch and two-twelfths. The length of the rays appear to have
been about two inches one-twelfth ; their breadth, near the junction of
the rays with the body, is about seven-twelfths.

Affinities. —This beautiful species bear a striking resemblance to the
recent Astropecten aranciacus and its allies. No fossil species of this
genus, as yet figured, so clearly proves the true generic position of the
extinct forms as this.

Locality and Geological Position.—Engraved from a drawing by Mr.
J. Phillips of a specimen from the upper sandy beds of FOREST MARBLE,
Hinton-lane-end, Yorkshire. |

E. Fores.
April, 1849. ;

DECADE 1.PL.3. _

CONIASTER |
ASTROPECTEN 7

(Tertiary)

Geological Survey of the Woarttew Aingoonr.

#

| CONIASTER. Stommsin-8 Porves 3 ASTROPECTEN crispatus_ forbes.
2... MARCTRAMTS. Sores a ath armarus_— Forbes.

i Bone del’ i. Forbes dirext JW Lowzy fc. ©

pORITISG@ FOSSILS,

DecapE I. Puars III.

—_—_——

TERTIARY (EOCENE) SPECIES OF GONIASTER.

[Genus GONIASTER. Agassiz. (Sub-kingdom Radiata. Class Echinodermata. Order
Asteriade. Family Goniasterie). Body pentagonal; a vent on the dorsal surface; disk
much depressed, flat when dead; skeleton composed of tessellated plates, variously studded
with granules, spines, and in many instances, pedicellariz; rarely naked; margins
bounded by two series of large plates ; suckers biserial. ]

Fig. 1.
GONIASTER STOKESII:

E. Forses, in “ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 475.

Diagnosis. G. corpore pentagonali, angulis longe productis, lateribus
profunde lunatis: ossiculis lateralibus supertoribus diset oblongo-quadratis
depressis eu convexiusculis, brachialibus quadratis tumidis, extrorsum
abruptis ; omnibus punctatis, inferioribus similaribus.

Description.— Although I have never met with this very distinct
species in a perfect condition, numerous fragments of greater or less
dimensions give a very perfect notion of its size, form, and proportions.
The body was pentangular, with angles greatly produced, and even
attenuated at their extremities (fig. 1, a. and d.) into linear parallel-
sided arms. ‘The disk was flat, and, as well as the arms, bordered by a
double series of subquadrate, steep-sided, somewhat nodular, nearly
equal, thick marginal plates, the sides of which are quite equal in dimen-
sions to the summits (fig. 1, 6. and c.). These plates are coarsely but
rather regularly punctated on their exposed surfaces. ‘Their prominent
nodular summits seem often as if subtruncated. The nodular convexity of
each plate is placed towards its marginal extremity. The summits of the

superior plates are more prominent than those of the inferior. Towards

the prolonged extremities of the arms these nodulations begin to dis-

appear; but the plates are always highly convex in their centres, so as

to be strikingly distinct from each other, and to seem as if separated by

a deep sulcus. ‘The extremities of the rays are slightly swollen. They

terminate in a distinct small semicircular ocular plate, bordered on each

side by two (transformed marginals) small oblong oculars. The surface
ba it. | D

2 BRITISH FOSSILS.

of the disk dorsally is covered with small irregular and pentagonal
punctated flat plates, those towards the centre of the rays arranged in a
more or less distinct series. Similar ossicula occupy the interambulacral
spaces beneath. ‘The ambulacra are bordered by quadrate stout plates
of moderate dimensions, furrowed on their surfaces by three or four
strongly marked longitudinal grooves, which are the lodging-places of
small ambulacral spines.

This species must have attained considerable dimensions. The largest —

fragment figured (1, 6.) would indicate a star-fish measuring at least
8 inches from the extremity of one arm to the end of that most distant, of
which 24 inches would go to the disk. The marginal plates in this specimen
measure 3-16ths of an inch across, and nearly as much high. The num-
ber of margial plates in a full-grown specimen was probably about
28 on either side of each produced angle.

Locality and Geological Position.—Goniaster Stokesi1 occurs not
unfrequently in the London clay of Sheppey. The specimens figured
were communicated to the Geological Survey by Mr. Charles Stokes,
and Mr. Bowerbank possesses a number of fragments of the same spe-
cies. The peculiar convex, nodulose marginal plates, conspicuously
distinguish it from any other tertiary star-fish.

ire. 2:
GONIASTER MARGINATUS.

E. Forses, in “ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 475.

Driaqnosis. G. corpore 2—ossiculis lateralibus disci magnis, oblongis,
convexiusculis, rugoso-punctatis, marginatis ; margine elevato.

Description.— All that we possess of this species is a fragment, con-
sisting of five superior and as many inferior marginal plates, which,
however, present characters so distinct that they cannot belong to any
other described tertiary star-fish. The superior plates are large, oblong,
regularly declining outwardly, and low-sided. Their surface is but
slightly convex, thickly punctured all over, and bordered laterally by a
distinct elevated rim. ‘The inferior plates are similar, but have even

more elevated margins, and the rim is continued on them across their.

outer sides. What few body plates are visible are small and punctate.
The fragment measures one inch and one-eighth in length. The largest
plate is three-eighths of an inch in length, and less than two-eighths at
its broadest part.

Locality and Geological Position—The specimen is from the London
clay of Sheppey, and was communicated to the Geological Survey by
Mr. C. eee

BRITISH FOSSILS. 5

TERTIARY (EOCENE) SPECIES OF ASTROPECTEN.

[Genus ASTROPECTEN. Linck. (Sub-kingdom Radiata, Class Echinodermata.
Order Asteriade. Family Asterie). Body stellate, few (five) rayed; no vent; rays flat
on both sides, regular; surface of body, and upper sides of arms covered with paxille.
Ambulacra with two rows of suckers, bordered by spines. Margins of the arms bordered
by a double row of conspicuous plates.—The genera STELLARIA of Narpo and AsTERIAs
(restricted) of Acassiz are synonymous. |

Fira. 3.
ASTROPECTEN CRISPATUWS.

E. Forsss, in ‘‘ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 479—(icon.) Ansted, “ Geology,” vol. ii. p. 66, woodcut.

Draenosis. A. radiis late lanceolatis, attenuatis, angulis intermediis
valde obtusis; ossiculis marginalibus anguste oblongis, numerosis, spiniferis ;
disco lato. :

Description.—Disk broad, rays lanceolate, broad at their bases,
attenuated at their extremities, and forming very obtuse angles at their
junctions with each other; the lanceolate portion of the arms is about
one-fifth longer than the disk is broad. They are bordered by closely
set oblong, narrow plates, very numerous, about 36 on either side of each
ray in the largest specimen examined. ‘These marginal plates decline
outwardly. ‘Those bordermg the angles of junction preserve their
dimensions. All the marginal plates bear at their exterior and superior
edges short obtuse lanceolate spines. ‘The inferior marginal plates are
curved more regularly than the superior. The ossicula of the surface
and framework of the disk are very irregular. ‘The section of an arm
shows that it was of inconsiderable thickness, and, from the peculiar
shape of the marginal plates, edged at the sides. ‘The ossicles bordering
the ambulacra are of considerable dimensions. ‘The extremities of the
_ arms seem (judging from the fragment fig. 1, c.), to be much attenuated ;
but the plates bordering them preserved the proportions of those nearer
the body. ‘The breadth of the disk in the largest specimen I have seen
is one inch four-twelfths. The rays are nine-twelfths of an inch broad
at their bases. The marginal ossicles are four-twelfths of an inch
broad, by less than one-twelfth long. The thickness of a ray is less
than two-twelfths.

Locality and Geological Position.—In the London clay of Sheppey,
where specimens are not uncommon. ‘Those represented at figs. 36 and
3c, were communicated to the Geological Survey by Mr. Stokes.
Fig. 3a is a remarkably fine specimen, in the collection of Mr. Bower-
bank.

4 BRITISH FOSSILS.

Fic. 4.
ASTROPECTEN ARMATUS.

E. Forges, in “ Memoirs of the Geological Survey of Great Britain,”
vol. ii. part 2, p. 479.

Diaewosis. A. radiis lanceolatis, angulis intermediis valde obtusis, ossi-
culis marginalibus oblongis carinatis, extrorsum longé spinosis.

Description.—The only fragment of this very distinct species is the -
greater portion of a single arm. It exhibits a lanceolate, depressed
ray, with well-marked oblong carimated marginal ossicula, bearmg
towards their outer sides stout lmear spines, equal in length to their
breadth. The spines are set directly in connexion with the ridges.
About 19 plates, and as many spines in a row, are preserved. The
fragment measures nine-twelfths of an inch in breadth at its base, and
one inch three-twelfths in length; the spines and plates are respectively
about three-twelfths of an inch in length.

Locality and Geological Position.—This unique and curious specimen,
contained in the collection of Mr. Bowerbank, is from the London clay
of Sheppey:

E. Fores.
April, 1849,

" PECADE.L Ph.

Gealo ' ‘ eal Sr ep ot ty e United RKingoor, PROTAS TER 4

(Silvan )

i
4
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PROTASTER SEDGWwICKII __ Forbes.

a.

TW.Lowry fe.

Rupees ae si dl cy a Palle ets aia

Boat ll ot FOSS) is.

DecavE [. Puate lV.

—_—_———=

PROTASTER SEDGWICKII.

[Genus PROTASTER. Forszes. (Sub-kingdom Radiata. Class Echinodermata.
Order Ophiuride. Family Euryales.) Body circular, covered with squamiform plates;
genital openings in the angles of junction of the arms beneath; arms (simple) formed of

alternating ossicula. ]

Species Unica. Protaster Sedgwickiit. Forsus,

The remarkable fossil, of which, through the co-operation of Pro-
fessor Sedgwick, we are enabled to give a figure, is unique of its kind,
and has a peculiar interest in being the only representative of the tribe
Euryales as yet discovered in the fossil state. J refer it to that tribe,
- and not to the Ophiure, with which at first sight it might be con-
founded, on account of the alternation of the ossicula of the arms, a
conformation of which the Astrophyton and other genera of the former
group exhibit examples, whilst it is never seen in any genus, as yet
discovered, of the latter division. Like many other Silurian fossils, this
one affords but imperfect materials for an investigation zoologically of
its characters; such, however, as are to be seen in the specimens
hitherto procured, are sufficient to enable us to assert with certainty
that it is distinct both generically and specifically from any known star-
fish, whether recent or fossil.

Description—The specimen figured consists of tolerably preserved
impressions of the upper and under side of the disk or body, and of por-
tions of the arms. The disk is circular, and shaped like that of an
Ophiura. The arms are five in number, very narrow, equidistant, and
similar.

The upper and under surfaces of the disk were covered by small,
similar, more or less regular, polygonal or crescentic plates, imbricated
in scale-fashion, and having punctated surfaces. Those of the under
side of the body are smaller and more regular than those of the upper.
The mouth is central, and rather small in proportion to the disk. The
buccal apparatus is composed of ten parts or processes, arranged in
pairs ; half of each springs from the origin of each arm in a diverging
manner, and meets the corresponding half to form a lanceolate tooth-

[ 1. iv. | 7 E

2 BRITISH FOSSILS.

like projection, deeply indenting the cavity of the mouth. Of how many
separate ossicles each of the buccal processes was composed the spe-
cimen affords but very indistinct indication. ‘They seem to affect a
slightly falcate form at their extremities. The arms were composed of
alternating somewhat quadrate ossicula, the sides of which were deeply
indented superiorly, in order to form spiniferous crests. The spines
were apparently short, and not equal in length to the length of an
ossicle, obtuse, and few in arow. ‘The under surfaces of the brachial
ossicula were not indented laterally. The central portions of the upper

surfaces of the brachial ossicles were hollowed out slightly, and the

sutures between them deeply impressed. About twelve of the brachial
ossicles were imbedded in the disk, and the parts of the dorsal surface
of the latter, corresponding to the arms and central skeleton, do not
present traces of scales, a feature seen in existing Euryales.

The dimensions of Professor Sedgwick’s specimens are as follows :—

Breadth of disk, 0},ths inch.
Average breadth between the arms, 0,3,ths inch.
Breadth of an arm, at its junction with the body, 0;4th inch.

Locality and Geological Horizon.—Si.urian, from Ludlow rocks at
Docker Park, near Kendal, Westmoreland (specimen figured), asso-
ciated with Encrinites, and at Benson Knot, also near Kendal, in hard
sandstones, full of characteristic Ludlow fossils. Collected by the Rev.
Professor Sedgwick and Mr. John Ruthven.

EXPLANATION OF THE PLATE.

Fig. 1, under, and Fig. 2, upper side of the Docker Park specimen. Fig. 3. Restora-
tion to show the probable form and appearance of the animal, Fig. 4. Diagram of base
of an arm, buccal processes, and position of ovarian openings.

Epwarp ForsBgs. —
April, 1849.

PE I ee

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DECADE 1.PL.5,

Seological Surbep of the United Kingdom. SALENIA
‘ bs (Cretaceous.) ~

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SALENIA PpERsonaATA — Desrance.

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BRITISH FOSSILS,

DecapE I. Prats V,

SALENIA PERSONATA.

[Genus SALENIA. Gray. (Sub-kingdom Radiata. Class Echinodermata. Order
Echinide. Family Cidarites.) Body subglobose. Interambulacral segments very broad,
bearing (few) primary imperforate tubercles; ambulacral areas very narrow, without
primary tubercles; pores in single file; summit crowned with a complicated anal disk,
composed of five ovarian and five ocular plates, and one supra-anal plate; anus excen-
trical ; spines of two orders, the primaries long, slender, and cylindrical.—I regard the
genera PeLTastes and GonropHorus of AcassiZ, as sections of the genus SALENIA. |

Synonyms. chinus petaliferus (Desmarest, MSS.), DEerRANce, in
the 37th volume of the Dict. des Sciences Naturelles, p. 101 (1825) [it had
previously been clearly figured, but without a name, by Parkinson, in the
3rd vol. of ‘‘ Organic Remains,” pl. 1, f. 12]. Echinus areolatus, Konic.
Tcones Sectiles (1825), Fig. 100 (wrongly so named, not being the species of
Wahlenberg). Cidaris scutiger, MunstrR in Goxupruss, Petref. Germ.,
p- 120., pl. xlix., f. 4 (1826). Salenia seutiger. Gray, Zool. Proc., part 3,
for 1835, p. 58. Eichinus (Salenia) petaliferus, RozmErR, Verst. Nord
Deutschen Kreide- Geb, (1840), p. 30. Salenia seutigera, AGassiz, Echin,
Suiss., ii., p. 89, t. 23, f. 1-5, and Monog, des Salenies, p. 12, t. 2, f. 1-8?
Salenia personata, AGAssiz (who states that it is the MSS, Cidaris per-
sonata of DrFRANCE), Monog. des Salenies, p. 7, f. 1-8. Salenia petalifera,
Aacassiz, Monog. des Salenies, p. 9, t. 1, f. 17-24. SS. personata and S,
scutigera, AGAssiz and Drsor, Cat. Raisonné des Echinides, Annales des
Sc. Nat., 3rd series, Zool., vol. vi., p. 341 (1846).

Probable variety. Salenia gibba, Acassiz, Monog. des Salenies, p. 13,
t. 2, f. 9-16.

Diaenosts. SS. testa suborbiculari, dorso subdepresso, ared analt magna,
assulis levigatis, suturis assularibus punctatis, punctis parvis circularibus
seu triangularibus, margines assularum vix denticulantibus ; areis inter-
ambulacralibus in medio late granulosis.

In lettering our plate Salenia personata, we follow the nomenclature
of the general catalogue of Echinide by Agassiz and Desor, but do so
not without doubts of the justice of the nomenclature therein proposed,

[1. v.| F

9 BRITISH FOSSILS.

and can certainly offer no objections to the adoption of the specific appel-
lation petalifera, in preference to the other names cited in our synonyms.
Parkinson gave a creditable figure of this curious sea-urchin, along with
that of another and very distinct species (the Salenia ornata of Agassiz,
MSS.), which has often been cited by mistake as identical with its com-
panion. Defrance identified a French species with Parkinson’s, and
adopted Desmarest’s manuscript name of petalifera. It would appear,
however, from the statement of Professor Agassiz, in his monograph of
Salenie, that Defrance himself used the name personata for a fossil which
the distinguished naturalist of Neuchatel regards as the type of the
species before us. ‘The Salenza figured by Goldfuss, under the name of
Cidaris scutiger, does not seem to me to differ essentially from our Bri-
tish species, and I cannot see those distinctions which Agassiz has pointed
out between it and the one we figure, at least in Goldfuss’s excellent
representation ; though that figured by Agassiz himself as scutiger, cer-
tainly presents differences, especially in the indentations of the sutures
of the anal plates, which may indicate a distinct variety if not species.
Description.—Body subglobose, depressed above, divided into five
equal portions by the five series of ambulacral plates, which stand out
rather more prominently than the interambulacrals. Anal disk broad
and slightly convex in some specimens, much more so than in others ;
its outline is slightly sinuous. The centre of it is occupied by the supra-
anal plate, which is of a hexagonal shape, broader than long, prominent
dorsally and centrally, excavated in form of crescent to make the anterior
margin of the anus. In front of it is the anterior ovarian plate, lyrately
oblong, longer than broad, broadest posteriorly and centrally, perforated
in the centre by a large ovarian pore. ‘The lateral ovarian plates are
similar in form, but rather shorter. All have their frontal or free
margins prominent in the centre. The posterior ovarian plates resemble
the others, except that their superior and inner angles are truncated
crescentically, and strongly margined, to go towards the formation of the
anal rim. ‘They are all perforated by ovarian pores, more or less
marginated. In many specimens the anal rim partially encroaches on
the posterior ovarian pores. The ocular plates are of much smaller
dimensions, transversely and subtriangularly oblong, their inner sides
forming the prominent portions of the triangle, and de frontal margins
the bases. Their imer sides unite with the inferior and lateral parts of
the neighbouring ovarian plates, the superior and lateral parts of which
unite with each other, and their superior margins with the supra-anal
plate. At the angles of junction of every three plates is a deep exca-
vation or punctation, and another in the centre of the line of union
between every two plates. Thus there are nine punctations around the
borders of the three anterior ovarian plates, six around each of the pos-

BRITISH FOSSILS. 3

terior ovarians, and three around each of the oculars. The pits at the

junction of three plates are triangular, those at the junction of two,
circular. They are never prolonged as linear notches into the substance
of the plates. The surfaces of the latter, in a few rare specimens,
exhibit indistinct indications of radiated ribbing. The anus itself is

subcircular, slightly inclining to transversely oval. It is bordered

by a very prominent rim, formed of the elevated margins of the pos-
terior ovarian and supra-anal plates. The sutures of parts of the rims
appear in many specimens as if consolidated.

The ambulacra are composed of two slightly sinuous poriferous grooves,

and separated by the ambulacral spaces. ‘The latter are narrow, and

through a great part, of nearly equal dimensions. Each ambulacral
plate bears a marginal tubercle, and one or two smaller ones on its
inner or central side. ‘The marginal tubercles, being nearly of an
equal size, form a closely ranged border to the ambulacral spaces; the
interspace between the borders is occupied by alternating tubercles
of smaller dimensions. ‘The poriferous avenues are depressed and very
narrow. ‘The pairs of pores are ranged in single file, except immediately
near the mouth, where they are double and triple ranked. Each pore
is separated from its fellow by a rather prominent ridge. ‘The inter-
ambulacral spaces are, in their centres, three times the breadth of the
ambulacrals. ‘They are composed of few plates, some of which bear
areolated spaces, surrounding primary spiniferous tubercles. ‘These are
borne on elevated prominences, which form a dentated margin around
their bases. The primary tubercles are not equal in diameter to the
breadth of the rings surrounding them. The edges of these circles
are bordered by a rather scattered series of secondary tubercles, usually
about seven in number. Of the primary tubercles and their areole,
there are three most conspicuous on each interambulacral area, two to
the left, and one, nearly centrical, on the right side. Down the centre
of each interambulacral area runs undulating an elevated, but plane
space, occupied by tertiary tubercles, closely and rather irregularly set,
bordered by the secondary tubercles which bound the rims of the
areolz. There are no tertiary tubercles in the spaces between one areola
and another of the same vertical series. |

The mouth is round, and not very large, as compared with the dia-
meter of the body. Its margin is deeply notched opposite each poriferous
suture, and sinuated in the interambulacral intervals. It is bordered
all round by a more or less thickened rim.

In a well-grown specimen there are about 38 pairs of pores in each
series, and about 18 bordering secondary tubercles on each side of an
ambulacral space.

As yet the spies are unknown.

VO) Ad Rs ee Tet NR ty ee
ae i : Ne

4 BRITISH FOSSILS.

Dimensions of a well-formed example.

Diameter’ se eh) hee ee nee ee
|g Rest 3 1 Parone Ween reer cnet ine Pat ane k's sl
Breadth of anal-disks ¢ 4, |) «iets JOssyeeane
Breadth of an ambulacral area, , , . « Or ,,
Breadth of an interambulacral area . . . Of ,, *
Breadth of mouth 45" 9% le jaa om Phe Gee

2?

Locality and Geological Position —Plentiful in the UPPER GREEN-

saAnD at Warminster. (Survey Collections.)

Foreign Distribution—In the Craie chloritee of France, Bavaria,

and Minorca, and Hills-conglomerat of North Germany. .

EXPLANATION OF THE PLATE,

Figs. 1, 2, and 3. Upper, under, and lateral views of a Warminster specimen. Fig, 4.

Genito-anal disk. Fig. 5, Two ambulacral areas, and one interambulacral greatly mag-.

nified. Fig, 6. Arrangement of the pairs of pores near the mouth. Fig, 7. Ambulacral
plates and pores. Fig. 8. Relative arrangements of ambulacral and interambulacral
plates. Fig, 9. An interambulacral plate, with its tubercles. Fig. 10. A primary tubercle
seated on its pedicle, with the surrounding secondary tubercles, seen in profile.

E. Forses.
April, 1849. ,

DECADE 1.PL.6.

ECHINUS
( Cretaceous. )

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BRETISH FOSSTES:

DecapE I. Puare VI.

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ECHINUS GRANULOSUS.

[Genus ECHINUS. Linnaeus. (Sub-kingdom Radiata. Class Echinodermata. Order
Kichinide. Family Cidarites.) Body more or less spherical; ambulacral and inter-
ambulacral segments developed, bearing on their plates tubercles of various sizes; anus
centrical, not furnished with regular calcareous valves, surrounded by a circle of five
ovarian and five ocular plates, all perforated; ambulacral avenues composed of pairs of
pores ranged in series of three or more; spines of one order. ]

Synonyms. Lchinus granulosus, MunstTER, in Goupruss, Pet. Germ.,
p- 125, pl. 49, f.5 a, 6. Echinus Bennettie, Kania, Icon. Sect., p. 35.
Fichinus granulosus, GRATELOUP, Mem. Ours. foss., p.82. Echinus granu-
losus, DusARDIN, in second edition of LamMArck, An. sans Vert., vol. iii.,
p- 872. Arbacia granulosa, Acassiz, Cat. Syst., p. 12. Morris, Cat.
Brit. Fos., p. 48. Acassiz and Desor, Cat. Rais. des Echinides, Ann. des
Se. Nat., 3rd Ser., vol. vi., Zoologie, p. 356.

Diaenosis. . &. assulis numerosis, centro-lateralibus angustissimis, dense
tuberculatis ; tuberculis primariis parvis equalibus, regulariter in seriebus
horizontalibus dispositis ; poris ambulacralibus in seriebus triplicibus verti-
calibus et ut in ordine simplici dispositis, sed prope orem vere subobliquis.

This pretty and plentiful little fossil urchin was first figured as Bri-
tish, though very imperfectly, by Mr. Konig, in his “ Icones Sectiles,”
under the name of Echinus Bennettia. tnd as a German species, by
Goldfuss, under the name of Echinus granulosus, given it by Munster.
The figure and description in the “ Petrefacta Germanica” are so com-
plete, that we cannot hesitate to adopt the name by which this fossil 1s
known to geologists and collectors.

In recently published catalogues it figures as a species of Arbacia,
and in the “ Catalogue Raisonné des Echinides”’ of Agassiz and Desor
heads the second type of that genus—the section in which the tubercles
are described as uniform all over the surface of the shell. Echinus
monilis, a species bearing considerable resemblance to that before us,
and well known both in the fossil and recent: state, having been found in
French and British upper tertiaries, and by myself alive in the Medi-
terranean, is placed by the authors quoted at the head of their first type
of the genus. Arbacia is a group of Echinide, founded by Mr. J. E.
Gray in 1835 (Zool. Proc., part 3, p. 58), for a section of the genus

Ele, Vib G

2 BRITISH FOSSILS.

Echinus, in which, according to the founder, the body is depressed, the
ambulacral areas very narrow, the ambulacra narrow, straight, and con-
taining pairs of pores ranged in a single row, the ovarian and inter-
ovarian plates middle-sized, and the anus covered by four valves. ‘The
types of this genus, as cited by its founder, are the Echinus pustul/osus
of Lamarck and the EF. punctulatus of the same author. The genus is
a good one, though its characters were partially misunderstood by its
founder, for the ambulacral pores are not uniserial. It presents a very
peculiar and undescribed structure of the ocular plates. The characters
of Arbacia, as given by Agassiz, are, however, altogether different from
those just cited, for he confines it to “small subspherical urchins, having
the test covered by numerous little smooth-based imperforate tubercles,
ranged in numerous rows on the interambulacral aree, and sometimes
also on the ambulacral ones. Pores ranged in a simple series. Mouth
circular, without deep notches. Genital apparatus narrow and ring-
shaped.” All the species enumerated in his synopsis are cretaceous or
tertiary fossils. ‘The Arbacie of Gray are transferred to Echinocidaris
of Desmoulins, a genus synonymous with Arbacia, in the sense of its
founder’s definition. In that sense the several fossils enumerated under
Arbacia, in the ‘“‘ Catalogue Raisonné des Echinides,”’ cannot be so
called,“ for neither Echinus monilis nor Echinus granulosus partake of
its characters. They are, in fact, true Echini, as I have elsewhere
shown, when describing the living LE. montlis, and am prepared to
prove, with respect to the fossil EL. granulosus, that neither the degree
of convexity of shell, or abundance of spiniferous tubercles, or the
arrangement of the pores (which are not in simple series), or the struc-
ture of the mouth or of the genital apparatus, can warrant the consti-
tution of a generic group distinct from Echinus, using the word in its
restricted sense, for the species in question.

Description—The body varies in shape from sub-globular (as in
fig. 2), to sub-conical (as in fig. 5), and to the unarmed eye resembles
a miniature melon, studded over by minute uniform tubercles, and
divided into five broad and five narrow segments, by narrow, depressed,
punctured furrows, radiating above from a circle of apical plates, sur-
rounding a central perforation, and converging below towards a much
larger central circular orifice.

The ambulacral and interambulacral segments are composed of similar
polygonal plates, very numerous. Those of the former are shortly
oblong, those of the latter very narrow in vertical dimensions. All are
covered by small, imperforate, thick-set primary tubercles, separated by
minute secondary ones. ‘The former alone were probably spiniferous,
the latter probably indicate the position of the bases of pedicellarie.
The tubercles of both the ambulacral and mterambulacral plates are

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BRITISH FOSSILS. 3

similar, but on the former the secondary granulations are more numerous

than on the latter. On the ambulacral plates the primary tubercles

are ranged in a single line, transverse to the form of the test, giving the
surface a lineated aspect. In some specimens they fall so directly
~under each other, as to give the appearance of vertical as well as
horizontal granulations. ‘There are about eight or nine primary
tubercles on a central interambulacral, and three on an ambulacral
plate. The line of junction of the two series of interambulacrals, and
sometimes of the ambulacrals in each segment, is not unfrequently
strongly marked. In such specimens the interambulacrals occasionally
exhibit a tendency to vertical carination. Opposite each plate are three
pair of pores in the ambulacral sulci, which are very narrow, and run
almost straightly down the sides. The number of pores are a multiple
of the number of plates by three. The pores appear to form a single
series, but are not really so arranged, as we may convince ourselves by
tracing the poriferous avenues to their junction with the mouth. As they
approach that orifice they exhibit a tendency to form oblique rows, and
at length definitely fall into ranks of threes (fig. 11). Hence the
distinction between the genus Arbacia (in the sense used by writers on
fossils) and Echinus, founded on the arrangement of the pores in a single

- series in the former, and in many series in the latter, is a mistake. This

is quite as plainly seen in the so-called Arbacia monilis, where the pairs
of pores are ranked in fours so distinctly all over the shell that it is
strange such an arrangement should have been overlooked. In an
undescribed green-sand urchin, brought from Portugal by Mr. Daniel
Sharpe, the general aspect of the shell, the arrangement of tubercles,
&c., so closely resemble the species we are describing, that at first
sight they seem identical, but when the poriferous avenues are examined,
the pairs of pores are seen to fall into very oblique and unmistakable
ranks of threes throughout. The mouth is circular, rather small in
proportion to the base, and very slightly notched opposite the ambu-
lacral furrows. The anal and ovarian circle is small in proportion,
being about two-fifths of the breadth of the mouth. The diameter of
the ovarian and anal circle is to the mouth as the maximum breadth of
the ambulacral to that of the interambulacral segments. The anus
was not protected by definite and symmetrical testaceous valves. The
ovarian plates are subtriangular, and perforated in their centres by a
conspicuous oviducal pore. One of them is in some specimens slightly
larger than the rest, and exhibits traces of a madreporiform tubercle.
The ocular plates are small, and angularly reniform ; the perforation
for the ocelli is in the central angle of their excavated and outer mar-
gins, thus presenting a slight abnormality of position. The ovarian
circle is exactly the diameter of the widest and most central portion of

A BRITISH FOSSILS.

the ambulacral segments, as the mouth is of the interambulacral. I
have not met with the spines. The shell is thin.

The largest example I have seen measured eight- -twelfths of an inch
in diameter. ‘The proportion of elevation to breadth varies in almost
every individual, and is quite as variable as it is well known to be in
the recent Echinus. The specimen mentioned was five-twelfths of an
inch in height, and had 34 plates in vertical succession, composing each
half-segment, and consequently there were above 100 pairs of pores in
each avenue, indicating as many suckers.

In four examples from the same locality the proportion of diameter
to height was respectively as 17 to 10, 15 to 11, 12 to 11, and 12 to 8.
The Arbacia conica of Agassiz, of which we have no other description
than that it is near granulosa, “ Mais plus haute et plus conique,”
cannot, therefore, be regarded as a species, or even as a marked variety.
With the variations of proportion the shell becomes more or less
globular.

Locality and Geological Position—Very abundant in the upper
green-sand of Warminster. (Survey Collection.) Chute Farm, Wilts.

On the Continent it was first noticed in the upper green-sand of
Regensburg, in Bavaria. It occurs in France in the Craie chloritee of
VIsle d’ Aix, Le Mans, and (Arbac. conica) Calvados.

The Echinus pelos, from the Neocomian of the canton of Neuchatel,
is its nearest ally and predecessor.

M. Grateloup states that it is found at Dax, and in the white chalk of
Pouillon.

EXPLANATION OF THE PLATE.

Fig. 1. A specimen of ordinary dimensions, seen from above. Fig. 2. The same from
the side; and Fig. 3, from below. Figs. 4, 5, and 6. Outlines of specimens of different
ages, showing extreme variations of form. Fig. 5 appears to be the Arbacia conica of —
Agassiz. Figs. 7 and 8. Upper and under magnified views, showing the arrangement and
articulations of the plates, which, for better display, are partly represented without their
tubercles. Fig. 9. The circle of ovarian and ocular plates. Fig. 10. Ambulacral and
interambulacral plates, with portions of avenues taken from the central portion of the
side, showing the arrangements of the primary and secondary tubercles. Fig. 11. Portion
of avenues near the mouth, showing that the apparent single arrangement of the pairs
of pores is deceptive, and that they are really three-ranked. Fig. 12. One of the primary
tubercles, seated on its elevated base, and surrounded by secondary granules.

E.. Fores.
April, 1849. ,

DECADE 1.PL 24

GALIERITES
(Cretaceous )
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CA LERITES GDISCODiEES. supucuLUS____ Leskeé.

BALES TOSSES.

DecaveE [. Puare VIL.

GALERITES (DISCOIDEA) SUBUCULUS.

[Genus GALERITES. Lamarck. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Cassidulide.) Body more or less hemispherical, always tumid ;
ambulacra simple, continuous, radiant; mouth central, inferior ; anus inferior or sub-
marginal ; tubercles perforate. |

[Sub-genus Discoidea. Body hemispheric, circular, flat-based ; tubercles in regular
series ; inside strengthened by strong ribs. ]

Synonyms. Discoides subuculus, Kurt, t. 14, f. 57 (copied in Enc.
Meth., pl. 153, f. 14-17). Echinites subuculus, Leskx. ap. Kuen, p. 171,
Echinus subuculus, GMELIN, p. 3183. Gralerites rotularis, LAMARcK, An.
sans Vert. iii, p..809. Discoides subuculus, Parkinson, vol. iii., p. 21,
opi, Ti., fig. 7. Galerites subuculus, Gotpruss, p. 129, ‘pl. 41, f.2. Dis-
coidea subuculus, Bronn, Lethea, p. 615, t. 29, f. 29. Discoidea rotularis,
Gray, Ann. Phil:, 1825; Acassrz, Prod., p. 186. Diéscoidea subuculus,
Desor, Mon. Gal., p. 54; Acassiz and Drsor, Cat. Rais. des Echin. Ann.
Sc. Nat., 3rd Ser., t. 7, p. 146. Galerites (Discoidea) subuculus, RoEMER,
Nord Deutsch. Kreide Geb., p. 31; Mixuer, Aach. Kreideformation, p. 8.

Diagnosis. G. (Discoidea) parva, hemispherica, plus minusve con-
vexa, marginibus rotundatis, ventre plus minusve excavato; areis ambula-
cralibus centro-lateralibus dimidium arearum interambulacralium adequan-
tibus ; ano magno ; assulis ambulacralibus 4 ad assulam interambulacralem.

Var.a. Ambitu orbiculari, marginibus compressiuscults.—D. subuculus
auctorum. Loc., in arena viride.

Var. 6. Ambitu subpentagonali, marginibus rotundatis.—D. infera,
Desor, Cat. Rais., p. 147? Loc., in ereta alba.

A wretched figure in Plott’s “ History of Oxfordshire,” (1677, p. 140,
pl. 8, f. 9,) is supposed to be the first representation of this fossil. It is
described by Plott, as a “ Button-stone from Teynton, a mere production
of nature, except we should take it for a new sort of echinite not yet
discovered, which is wholly left to the reader’s choice.” Lister, in his
book, “De Lapidibus Turbinatis,” copies it as an echinite. Klein
quotes the same figure for his Discoides subuculus, and gives figures
himself (t. 14, f. 57) sufficiently recognisable. It is the type of the
genus Discoides of Klein, separated by that author from his genus

fr. vii. | H

2 BRITISH FOSSILS.

Conulus, of which Galerites albogalerus is the type. Leske, in his:
edition of Klein (p. 171), reunites the genera, and describes the species
in detail. He remarks, however, that the figure of Plott is too doubtful
to be quoted as a representation of the Hchinites subuculus, and that it
seems rather to represent a madrepore. He exercises more critical
judgment in the examination of his references than is shown by some
of his successors; who, indeed, whilst quoting him, do not appear to
have read his text. He rejects, also, a figure in Langius, whose work —
Ihave not been able to see. Since then it has been figured, seldom
very well, by Alexander Brogniart, from French specimens, by Goldfuss
and Bronn from German examples, and by Parkinson (badly) from
English ones. The latest and best representation is that given in the
“‘ Monograph of Galerites,” by Desor. | : “tte

Description—The body exhibits an outline exactly orbicular, or
occasionally exhibiting a very slight tendency to a pentangular contour.
It is regularly convex above, but to a greater or less degree in different
specimens, exhibiting every gradation of variation, from prominently
conical to subdepressed. ‘The upper surface is divided into five broad
and five narrow segments, by the avenues of pores, which regularly
radiate from the ovarian circle crowning the summit. The under
surface is more or less flattened, with more or less rounded margins,
and a more or less concave centre, in the middle of which is the
circular mouth, and between the mouth and the posterior margin a
large oblong anus.

The interambulacral segments are, in their widest part, rather more
than twice the breadth of the ambulacrals. The plates composing their
dorsal portion rarely exceed 13 in number in full-grown specimens, of
whatsoever shape. ‘The central ones are broader than long ; those near
the summit more and more nearly of equal dimensions in both direc-
tions: but whatever be their horizontal diameter, their vertical measure
is nearly the same in all. Their surfaces are thickly studded with
minute secondary granules, more or less regularly arranged, often
appearing as if placed in horizontal series. Each plate exhibits a more
or less distinct subcentral carination, so that im many specimens the
interambulacral spaces appear as if partitioned by two diverging keels,
one on each side of the line of junction of the interambulacral plates.
In the line of carination each plate bears a prominent primary tubercle,
and in an horizontal row with it, towards the imterambulacral suture,
are two or three others similar in size and shape; whilst on the other
division of the plate, towards the avenue, two or more similar tubercles
are also seen, placed in two oblique series with reference to the position
of the tubercle on the carina. Consequently, on the avenue side of
each carina, in the interambulacral spaces, the tubercles appear as if

BRITISH FOSSILS. a

arranged in ascending oblique rows; and, on the centro-sutural side,
in horizontal rows. Towards the margin the tubercles become more
- numerous, and sometimes less regularly disposed. ‘The plates of the
ventral surface are of equal vertical dimensions with those of the dorsal,
and similarly ornamented. In well-grown specimens they are from
six to eight innumber. The suture of articulation of the interambu-
lacral plates with each other varies in degree of straightness, or zigzag,
in different specimens ; and is most nearly straight when the dorsal
surface is least depressed.

The ambulacral plates are very numerous and narrow, four of them
going to the vertical diameter of an interambulacral plate. They are
closely studded with granules like the latter, and each bears usually
one primary tubercle. ‘These tubercles are so arranged that they do
not fall in direct vertical rows, but form oblique series of threes, or, ~
as in some specimens, where alternate plates have their primary
tubercles suppressed, in twos. On the ventral surface the tubercles
are similar, except that they are often larger than those on the
dorsal. Each plate corresponds to a pair of pores in the ambulacral
avenue. ‘The avenues are impressed, quite straight, and have the pairs
of pores in regular succession, single file. ‘They have a tendency to
become obsolete near the mouth. ‘The two pores of each pair are
obliquely set with respect to each other. As there are about 21 inter-
ambulacral plates in each vertical series, from mouth to apex, in an
ordinary specimen, the number of ambulacral plates will be about 84,
and that of pairs of pores the same. ‘The primary tubercles are placed
on elevations in areolated spaces, and are invariably perforate.

‘The mouth is circular, and occupies the centre of the more or less
concave ventral surface. Its breadth is rather less than the distance
from its side to the outer margin. The anus occupies a considerable
part of the ventral space between the two postero-lateral ambulacra and
the margin. It is of an ovate form, its greatest dimensions being
in the line of length, 7. e., from the mouth towards the margin, and its —
‘outer extremity is slightly pomted.

The apex is composed of the combined ovarian and ocular plates, and
is in great part occupied by a madreporiform tubercle. The posterior
ovarian pore is undeveloped, as in all the genus. The ocular pores
are distinct.

Casts of the interior differ from the external shape of the body in
exhibiting ten deep notches around the margin, extending to the mouth
on the ventral surface, and ceasing at about a third of the height on the
dorsal. Five of these unite near the mouth, and five continue singly to
it. The centre of the prominent interspaces of the latter is marked by
ashallow groove. ‘The groove corresponds to the line of suture of the

4A BRITISH FOSSILS.

ambulacral plates, and its prominent sides to the avenues of pores. The
ten deep notches are caused by as many internal ribs, which spring
from the inner sides of the mouth, and run up the wall under the cari-
nated portion of each series of interambulacral plates.

Dimensions and Varieties.—The ordinary breadth of this species is
about 7-12ths of an inch. The proportions of the breadth to the height
are very variable, even in specimens from the same locality, as may be

exemplified by the following instances of upper green-sand specimens

from Warminster: 1st specimen, breadth to height (in millemetres,)
14:10; 2nd, 14485 Srd, 12: 8; 4th, 11:9; bik 10a
variation in degree of elevation is accompanied by very great variation
in rotundity of margin and convexity of base. The most rounded spe-
cimens are those of a variety which occur in the white chalk. It com-
bines rotundity with height, and has usually fewer primary tubercles
than are seen in ordinary specimens. In no essential respect, however,
does it differ from the green-sand form, and may be paralleled exactly
by exceptional specimens of the latter.

In the “‘ Monograph of Galerites,” by Desor, and in the “ Catalogue
Raisonné des Echinides,” four species of Dvscoidea allied to subuculus,
are enumerated. The first of these, Discoidea minima (Agassiz),
founded on a single example from the chalk marl of France, seems,
judging from figure and description, to be only one of the less conical
forms of the young of the species, such as not uncommonly occur at
Warminster. The second, Discoidea pisum (Merian), unfigured, is said
to be exactly like D. minima, and only distinguishable from it and
subuculus by having distinctly perforate primary tubercles. This, how-
ever, is the case with well-preserved specimens of every Discoidea, and
is a generic, not specific, distinction. The third, Discoidea turrita
(Desor), described and figured from a single example, is represented
as proportionally higher than subuculus, and differmg in having several
vertical series of primary tubercles equally prominent on the inter-
ambulacral spaces, and not two only, like those on the keels. But we
find in British specimens these characters combined or not, and occur-
ring in individuals not uncommonly, besides exhibiting every degree of
transition into the ordinary features of the species. The fourth is
merely named in the ‘“‘ Catalogue Raisonné ;” it is the Discoidea infera
(Desor), from the white chalk of Fécamp, said to be very near
subuculus, but differing in having the primary tubercles conspicuous only
on the ventral surface. Specimens of our variety from the white chalk
—the most distinct looking form of all—yet certainly not essentially so,
accord very well with the brief and insufficient notice given in the cata-
logue.

Allied Species.—Although I have little doubt that the several so-

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called species just mentioned are only slight varieties, if as much, of
subuculus, there is, however, a white chalk Galerites, of the section
Discoidea, in the cabinet of Mr. Dixon, of Worthing, and figured by
that gentleman in his forthcoming work on the geology of Sussex,
which, whilst very closely allied to the species here described, presents
certain characters which are not present either in green-sand specimens

_of subuculus, or in those from the white chalk itself. In form and size

it resembles ordinary examples of that species, and the proportion of
the ambulacral to the number of interambulacral plates is the same, nor
does the granulation of the surface materially differ. The proportions

of mouth and anus, and their dimensions, as compared with the entire

ventral surface, are so very different, and characters founded on such
differences appear to be so constant in this genus, that I feel bound to
regard it as distinct. The mouth, instead of being (as in subuculus)
nearly equal in diameter to the distances between its sides and the
margin of the inferior surface, is scarcely half that size, and the anus,
instead of occupying the greater part of the space between the mouth
and the margin, fills less than a half of it; consequently the appearance
of the base, with its perforations, is materially different, and as I can
find no specimens presenting intermediate characters among those of
the subuculus, either from green sand or chalk, I feel bound to consider
this a distinct species, and have named it Galerites (Discoidea) Dixont.

In the preceding account of Galerites subuculus, and in my notes on
Galerites subcylindrica (Dec. 1., pl. vii.) I have considered the Galerites
rotula of Alexander Brongniart (Geognosie des Terrains de Paris, pl.
9, f. 13, A. B. C.) as identical with the former species, and his figure as
a representation of a large specimen of it. Jam induced to do so on
account of the evident manner in which the subcarination of the halves
of the interambulacral spaces are indicated in his figure (13 A.), whilst
the inferior surface is represented as thickly covered with nearly equal
tubercles. Unfortunately no figure of the anus is given, to enable us to
decide with more certainty. On one of the figures an appearance as if
of a supramarginal anus is indicated, and this no doubt has led M.
Charles Des Moulins to regard it as a Pyrina, and to name it Pyrina
rotula. If his view of its characters be correct, it has certainly nothing
to do with the section Discordea. Agassiz has, however, considered
Brongniart’s figure as the type of his Discoidea rotula—a very different
species, and which, since our note of Galerites cylindricus was put in
type, I am still more inclined to identify with the Discoidea there de-
scribed, from the junction beds of the chalk and green sand, and of
which Mr. Morris has afforded me opportunities of seeing a number
of specimens, of different ages, from Charldon, in Dorsetshire. An
examination of them, and of their casts, confirms me in my opinion of the

| H 2

6 BRITISH FOSSILS.

propriety of uniting Discoidea rotula of Agassiz, and Discoidea favrina
of Desor, since the character of the notching on the casts varies in dif-
ferent specimens. Discoidea conica, of Desor, I take to be the same
species, assuming a more pentagonal form, a variety apparently not
uncommon among British examples. The Diéscoidea rotula of Mr.
M‘Coy, from the upper chalk, must surely be something quite distinct.
The young of the species, to which I would reserve the name Galerates
(Discoidea) favrinus, might be confounded at first sight with subuculus,
but is very different on close examination. It presents an orbicular
outline, with a strong tendency to become pentagonal. It is regularly
convex above, with more swelling sides, and, consequently, a flatter
summit than subuculus has, whilst its margins are often nearly as much
rounded as in that species. ‘The interambulacral segments are, in their
widest part, thrice the breadth of the ambulacrals, and the ambulacra
widely diverge from each other when proceeding from the summit,
characters which will at once distinguish between this form im its young
state and subuculus.

Locality and Geological Position.—It abounds in the UPPER GREEN
sanp of Warminster, Chute Farm, Wilts; in the junction bed of GREEN
SAND and CHALK MARL at Maiden Bradley, Wilts. (Survey Collec-
tions.) Lowrr cHaLkK, Weymouth (Morris). In the wHrrE cHALK of
Kent, but not so common. Morris (Cat. p. 52) mentions its occurrence
in the LOWER GREEN SAND of Hythe, Kent.

Foreign Distribution.—On the Continent it occurs in the chalk marl
of France and Germany. Hillsconglomerat of Essen (Miiller).

EXPLANATION OF THE PLATE.

Figs. 1 and 2. Upper and under views of a green-sand specimen. Fig. 3. Profile of a
conical green-sand specimen allied to var. 6. Fig. 4. Sub-depressed variety. Figs. 5, 6.
Magnified representations of the dorsal and ventral surfaces, showing the arrangements of
the plates. Fig. 7. Arrangement of the ovarian and ocular pores on the summit. Fig. 8.
Ambulacral and interambulacral plates, with their tubercles, granules, and pores. Fig. 9.
Primary tubercle surrounded by granules. .

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Decaprb I. Prare VIII.

GALERITES (DISCOIDEA) CYLINDRICUS.
[Genus GALERITES. Lamarck. (Sub-kingdom Radiata. Class Echinodermata.

Order Echinide. Family Cassidulide.) Body more or less hemispherical, always tumid ;

ambulacra simple, continuous, radiant; mouth central, inferior; anus inferior, or sub-
marginal ; tubercles perforate. |

{Sub-genus Discoidea. Body hemispheric, circular, flat-based; tubercles in regular
series ; inside strengthened by strong ribs.]

Synonyms. Galerites eylindricus, LAMARcK (in 2nd Ed., iii., p. 311).
Conulus Hawkinsii, Mante.y, Geol. Trans., New Ser., vol. iii., part 1,
p. 208. Galerites Hawkinsii, Desmoutins, Tab. Syn., p. 254. Galerites
canaliculatus, Goupruss, p. 128, pl. 41, f. 1. Sceutella depressa and S.
‘hemispherica, Woopwarp, Geol. Norfolk, p. 52, t.5, f.4and 5. Discordea
cylindrica, Acassiz, Echin. foss. Suiss., part 1, p. 92, t. 6, f. 13. 15.
Desor, Monog. Galerites, p. 58, t. 8, f. 8-16. Agassiz and Desor, Cat.
Rais. des Echin., Ann. Se. Nat., 3rd ser., vol. vii., p. 147. Galerites (Dis-
coidea) cylindrica, RamER, Nord-Deutsch. Kreide Geb., p. 31.

Draenosis. G. (Discoidea) inflata, magna, hemispheriea seu (adulta),
subcylindrica; ventre plano, ano parvo; areis ambulacralibus tertiam
partem arearum interambulacralium equantibus ; assulis ambulacralibus 5
ad assulam interambulacralem appositis.

Desor, in his ‘“‘ Monograph of the Galerites,’ and Bronn, in his
“Index Paleontologicus,” refer to this beautiful fossil the figures
given by Leske of his Echinites quaterfasciatus and Eehinites sexies-
fasciatus (Leske ap. Klein, t. 47, f. 3-5, and 50, f. 1 and 2, copied in
the “ Enc. Meth.” Echinus quadrifasciatus and Echinus sexfasciatus,
Gmelin, 3183 made two species of Galerites by Lamarck), considering
them as monstrous varieties; but a careful inspection of the figures of
Leske, representing two casts, is sufficient to show that they are the
nuclei of species of the subgenus Galerites, and not of the subgenus
Discoidea. Had they represented casts of monstrosities of G. eylindricus,
they would have exhibited the regularly arranged furrows caused by
the impressions of the internal ribs. The history of the species dates,
therefore, from its definition as such by Lamarck. Desmoulins and
Dujardins have confounded it with tertiary urchins, and added syno-
nyms to the Lamarckian name which do not belong to it. The best

[ 1. viii. | I

2 BRITISH FOSSILS.

representations of it are those given by Goldfuss and by Desor. ‘The
figures in Woodward’s ‘“ Geology of Norfolk,” referred to in the syno-
nyms, are slight but characteristic.

Description.—The outline is orbicular ; the ventral surface flat; the
dorsal very convex, varying in stages of growth from regularly hemi-
spherical to hemispherico-cylindrical, the latter shape being its final
condition. ‘The upper surface is sparingly granulated with minute
tubercles, and is divided into 10 narrow and 10 broad segments, those
of each set being of equal dimensions, by the poriferous avenues. The
under surface is nearly flat, similarly divided, impressed in the centre
for the mouth, and perforated between the mouth and posterior ara
for an elliptical rather small anus.

The interambulacral segments are, in their widest part, three times
the breadth of the veheiated: The plates of the dorsal surface, towards
the centre and lower parts of the sides, are horizontal, broad, and verti-
cally narrow, those only near the summit being of equal dimensions
everyway. Whatever be their horizontal diameter, their vertical mea-
surement is nearly alike in all. ‘Their surfaces are studded with
minute granules, somewhat scattered towards their sides, but clustered
towards their centres, where they group themselves moniliformly around
the few scattered small primary tubercles, of which there is only one on
the uppermost plates, though they gradually increase in numbers down
the sides to as many as seven or eight. Of these one is always on each
plate in the line of slight carination, which runs down each half of each
interambulacral area. The lowest series of plates, towards the margin,
bear numerous primary tubercles, of which those towards the centro-
ambulacral suture are arranged in regular horizontal rows. The inter-
ambulacral plates of the ventral surface are still more conspicuously
ornamented with rows of primary tubercles, each surrounded by a
conspicuous impressed circle, bounded by granules, which are larger
and more thickly set than on the upper surface. The inferior interam-
bulacral plates, towards the margin, are much narrower than those near
the mouth. The inferior interambulacral spaces bulge out on each
half near the margin; a bulging which is continuous with their carina-
tion above, and which indicates the position of the strengthening ribs
in the interior of the test.

The superior ambulacral plates are very numerous, and vertically
very narrow. ‘Their surfaces are speckled with granules, and at inter-
vals, generally of threes, the uppermost ones bear primary tubercles,
which become more numerous towards the centre and margin. Each

plate corresponds to a pair of pores in the ambulacral avenue, which is
scarcely, if at all, impressed. ‘The pairs of pores are larger and more
conspicuous on the dorsal than on the ventral surface. Dorsally four of

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BRITISH FOSSILS. &

them, and consequently as many ambulacral plates, correspond to each
interambulacral. On the ventrical surface they become doubled in
number, so as to form rows of twos, and near the mouth, where the
ambulacral plates widen considerably, two such rows go to each plate.
The primary tubercles are all perforate, and the rim of the protuber-
ance in which they are set is crenulated.

The mouth is small, obscurely pentagonal, and in diameter equal to
one-fourth of the distance between it and the margin. The anus is
oblong, and somewhat acute at each extremity. It occupies rather
more than one-fourth of the space between the mouth and the margin,
and is distant from the margin its own longitudinal diameter. It is in
the centre of an inferior interambulacral space, and is as if cut out of
the plates, its margins being on a level with them, except the inner
extremity, where there is a bulging.

The apex is composed of the combined ovarian and ocular plates,
and is often slightly prominent, in consequence of the convexity of the
ovarian plates, both individually and collectively. ‘The centre assem-
blage forms a slightly oblong or obscurely pentagonal area, conspicu-
ously divided into five parts by the five ovarians. Of these the left
antero-lateral is largest, and appears to represent a madreporiform
plate, and the left postero-lateral smallest. The other three are of
about equal dimensions. ‘The ovarian pores are placed near the outer
and central edges of each plate, except the posterior one, which is
obsolete. ‘The ocular plates are very small, obscure, and triangular.
The ocular pores are developed in all five. The greatest diameter of
the apical crown of plates is less than the breadth of the mouth.

Localities and Geological Position.—In the chalk marl and lower
chalk, Hamsey, near Guildford (Mantell). Markham Gayton (Wood-
ward). Charing (Morris). Lewes, Dover, Burham, near Maidstone
(Survey Collections).

Foreign Distribution.—In many localities (chalk marl) of France
and Germany.

DESCRIPTION OF THE PLATE.

Fig. 1. Hemispherical, or half-grown form of the species (Survey Collection) seen in
profile, and surrounded by an outline representing the perfect and cylindrical contour of a
full-grown specimen (in the British Museum). Figs. 2 and 3. The former specimen seen
from above and below. Fig. 4. Diagram of the mouth; and Fig. 5, of the anus. Fig. 6.
Centro-lateral, ambulacral, and interambulacral plates, with their tubercles, granules, and
pores. Fig. 7. Ambulacral and interambulacral plates, &c., of ventral surface. Fig. 8,
A primary tubercle, with surrounding granules, from the ventral plates. Bion Sea.
similar tubercle, from a dorsal plate.

4 : BRITISH FOSSILS.

Allied British Species.

In the collection of Mr. Tennant there is a very beautiful, though imperfect, specimen
of a Discoidea, nearly allied to, but quite distinct from cylindrica ; it was found in the

-

upper green sand of Somerset. It measures a little more than an inch in diameter, by

nearly eight-twelfths of an inch in height; is hemispheric, with a tendency to become
subcylindrical, and has plates horizontally proportioned and ornamented as in the cylin-
drica, but differing materially in their relative number; there being six (instead of four)

ambulacrals, and, consequently, as many pairs of pores, to each interambulacral. The

anus, moreover, is much nearer the margin, and larger than in the allied species.

The Discoidea favrina of Desor (Monog. Galerites, p. 62, pl. 7, f. 12-14, called rotula
on the plate), from green sand near Rouen, seems to be its near ally, if not identical ;
though it also resembles considerably the same author's D. conica (t. 7, f. 17-22). Unfor-
tunately neither figures nor descriptions indicate sufficiently the distinctive character of
the relative numbers of pairs of pores and interambulacral plates, The original Nucleolites
or Galerites rotula of Alexander Brongniart (see Cuvier, Ossemens fossiles, vol. ii. p. 614,

plate IX., fig. 13), appears, judging from the figure, to be only a rather large specimen of

Galerites (Discoidea) subuculus, and is quoted as such by M. Desor, in his synonymy
of that species. As such it is quite distinct from the Discotdea rotula of Agassiz, in the
‘‘Echinodermes fossiles de la Suisse” (Ist part, p. 90, t. 6, f. 10-12) ; but, nevertheless,
the same figure of Brongniart is again cited by M. Desor, as a representation of Discoidea
rotula, at page 61 of his “ Monograph of Galerites.” Dr. E. Sismonda, in his “ Memoir on
the Fossil Echini of Nice” (1843), enumerates Discoidea rotula, from the green sand near
Nice, and cites Alexander Brongniart’s figure, as well as those given by Agassiz in his
“ Descriptions of the Fossil Echini of Switzerland.” Unfortunately no figure is given of
the Italian species, nor are the relations of the ambulacral, as compared with the inter-
ambulacral plates mentioned in his description; but for the comparison he makes of it to
the Discoidea cylindrica, it is not improbable that our fossil may prove identical specifically
with that from Nice. In Mr. Morris’s “ Catalogue of British Fossils,” Discoidea rotula
is enumerated as a British fossil from the lower chalk of Maidstone and Dover, with a
reference to the figures of Brongniart and Agassiz, cited above. This mention of D.
rotula has escaped Mr. M°Coy, who again enumerates a fossil under that name, referring
to Agassiz alone as an authority, in his list of Mesozoic Radiata not included in Morris’s
catalogue, and preserved in the geological collection of the University of Cambridge
(Annals of Nat. Hist., 2nd ser., vol. ii., p. 420): the specimen he cites is from the upper
chalk of Norwich.

I think it not improbable that in the end we shall have to adopt the specific appellation
Favrina for the green sand species; and that the chalk specimens alluded to will prove

varieties of cylindrica; but a comparison of the types themselves only can settle the
matter.

E. Fores.
April, 1849.

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NUCLEOLITES CLUNICULARIS.

[Genus NUCLEOLITES. Lamarck (sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Clypeasteride.) Body oval or cordate, more or less tumid,
sometimes much depressed; ambulacra dorsally petaloid; anus supra-marginal; mouth
sub-central.] — :

[Sub-genus Vueleolites. Anus superior, in a furrow; mouth not surrounded by tubercles. ]

Synonyms. Clypeus clunicularis, Puriurrs, Geol. York, part 1, p. 115.
Nucleolites clunicularis, Bronn, Lethea Geognost., p. 282.

Diacnosis. NV. ambitu suborbiculari, subquadrato, antice rotundato,
postice bilobato; dorso convexo, apice subcentrali, vertice apical, postice
declivente; ambulacris anguste lanceolatis ; sulco anali profundo, lanceolato,
apiculato, ad apicem angustato, lobis posterioribus vix tumidis; ventre
concavo.

Var. a. Major, subdepressa, lata, lateribus tumidiusculis.—Spatangus
depressus, LESKE, ap. Klein, p. 238, t. 51, f. 1, 2 (copied in Enc. Meth., pl.
157, f. 5,6). Nueleolites scutata, Lamarck, An. s. Vert. 3, p. 36. Dz-
FRANCE, Dict. Sc. Nat., vol. xxxv., p. 213. WV. clunicularis, b. Bronn.
Leth., p. 288. WV. seutatus, Acassiz, Echin. Suiss. p. 45, pl. 7, f. 19-21.

Var. 8. Minor et media, convexa, lateribus tumidiuscults.—Nucleolites
gracilis, Acass1z, Echin. Suiss. p. 44, pl. 7, f. 10-12?

Var. y. Media, pyramidata, lateribus planiusculis—N. Sowerbit,
Derrance, Dict. Se. Nat., vol. xxxv., p. 213. NV. pyramidatus, M‘Coy,
(confirmat. in lit.), Ann. Nat. Hist., 2nd ser., vol. ii., p. 416, Dec. 1848.
[ Variety figured in our plate.]

The name clunicularis, as applied to a fossil sea-urchin, has its origin
with Lihwyd, who, in his “ Lithophylacii Britannici Ichnographia”
(1699), describes “ Echinites clunicularis. Echinites e lapide selenite,
quinis radiis e duplice serie transversarum lineolarum conflatis,” and
refers to certain figures in the works of Lister and Plot. The figure in
Plot (“History of Oxfordshire,” tab. 11, f. 12) represents a body which
is possibly Mucleolites clunicularis of Phillips, but so badly, that no anal
furrow, or anus, is delineated. ‘This figure is referred to by Lister,
in his book ‘‘ De Lapidibus Turbinatis (1678), cap. 11, titulus xxvi.,”
with a query whether it be identical with his own figure, t. 7, p. 26,

eis K

2 BRITISH FOSSILS.

which represents a fossil from Newton Grange, distinctly a Nucleolite,
and in all probability var. 6 of the species we are describing. ‘To
this figure the name Clypeus lobatus is applied by Dr. Fleming, in
his “ History of British Animals” (1828), p. 479, while the name
Clypeus clunicularis is given to the nucleolite figured by William Smith,
in his plate of the Coral Rag fossils (Strata Identified, 1817), and cha-
racterized in his “ Stratigraphical Table of Echini,” where it is marked
as ranging through upper oolite, “the clay over it,” cornbrash, and
coral rag. Smith gives no name further than noting it as species No. 2
of Clypeus, and, judging from his description, probably meant to include
both the clunicularis and dimidiatus of Phillips, whilst his figure seems
to represent the latter.* Fleming, in making two species ( Clypeus lobatus
and Clypeus clunicularis), overlooks the fact that the figure of Lister,
on which he founds the former, is the very representation quoted by
Llhwyd as representing Echinites clunicularis. We next come to John
Phillips, who, in his “Geology of Yorkshire,” part 1 (1835), figures in
his plate of fossils of the Cornbrash, under the name of “ Clypeus clu-
nicularis, Lilhwyd,” the nucleolite to which he would preserve the name.
Although the figure is far too slight, and no profile is given, there can be
no question as to what it is meant for, since, in the first place, the pecu-
liar form of the anal furrow is correctly mdicated ; and, in the second, a
new species of “ Clypeus,” from the coralline oolite, is figured under the
name C. dimidiatus, representing the only other British form to which
the figures of Plot and Lister might be applied. In the text of his
“¢ Letheea Geognostica”’ (1835-37), p. 282, Bronn distinguishes between
the Nucleolites clunicularis and the N. scutatus of Goldfuss (t. 43, p. 6),
holding the latter, in which opinion I agree, identical with the dimidiatus
of Phillips. At the same time he makes the Spatangus depressus of
Leske’s edition of Klein (JVucleolites scutata of Lamarck) a variety of
clunicularis. In the “ Catalogue Raisonné des Echinides” of Agassiz
and Desor (1847) the second fossil species of Nucleolites enumerated is’
clunicularis, Philips being the authority taken. For the reason, there-
fore, that the original name, clunicularis, as applied by Lihwyd, in all
probability included the form before us, whilst the stricter application of
it by Phillips is followed by Bronn and Agassiz, the reference of it by

* Since the above passage was written I have been enabled to examine Smith’s original
specimens, now lying among undisplayed treasures in the British Museum. They are ten
in number ; eight preserve the original lettering. “B.1.a. Bruham,’ is a sub-depressed
specimen of var. 6 of clunicularis; “B.1. a. Mayhill,”’ is dimidiatus ; “B. 1. 6.” locality
washed off, is clunicularis, var. 2; “B. 1. c. Wraxhall,” is clunicularis, var. B; “ B.1.d.?”
label washed off, but probably the Seaford specimen mentioned in the Stratigraphical
System, p. 69, is a dimidiatus ; “B.1. e.,” no label, probably the Trowle specimen, is
clunicularis, var. y; “B. 1. f.,” no label, probably the specimen from “South-west of

Tellisford,” is an intermediate form between « and 6 of clunicularis; “‘ B. 2.” is the same
form, and a second specimen marked “ B. 2.” isa small clunicularis, «.

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BRITISH FOSSILS. a

Fleming to Smith’s figure being a mistake, we retain it for the fossil
now figured, and the varieties here associated with it.

As, however, the name has been used with different degrees of restric-
tion, it is necessary further to inquire into the grounds of its limitation
by different naturalists, and also how far varieties more or less marked
have been separated with specific appellations from the normal form.
And this leads us to inquire what may be the Nucleolites scutata of
Lamarck (Animaux sans Vert., 3, p. 36). That author cites, first,
the “ Echinobrissus” of Breyn.* Next the Spatangus depressus of
Leske’s edition of Klein (1778), t. 5, f. 1-2, copied in pl. 157, f. 5-6,

of the “ Encyclopédie Méthodique ;” and he quotes a second variety,

with a higher back, also from a figure of Breynius. These figures
agree, as well as old and nearly worthless representations can agree,
with our variety « major; and I assent to the proceeding of Bronn, who
considers it a variety of clunicularis, of the normal form of which how-
ever he curiously enough quotes the figure in Breynius, first referred to
by Lamarck as a representation of his scutatus. In the second edition of
Lamarck, vol. ii. (1840), Dujardin brings in a new set of synonyms,
including Clypeus lobatus, Fleming, and Nucleolites clunicularis, Bronn.
They are brought together, as is too frequently the practice among
authors who make a great display of synonyms, without regard to their
origin, whether original and critical, or blindly copied. ‘The diagnosis
originally given by Lamarck is scarcely sufficiently distinct to warrant our
using scutata as a specific appellation in preference to clunicularis ; how-
ever, he gives no locality for his fossil. The name Spatangus depressus
of Leske is adopted as Echinites depressus by Schlotheim (Petrefacten-
kunde, 1820), and he gives Essex as a locality for his specimen. ‘This
was probably a mistake, and as there may be doubts about Leske’s
species, that name had better also be dropped. In the article Nucleo-
lites, “ Dict. des Sc. Nat.,” vol. xxxv. p. 213 (1825), Blainville quotes
the species Nucleolites scutata after Lamarck, and also mentions that the
locality is unknown. Alongside of it he gives Nucleolites Sowerbyi,
Defrance, with a few words of description stating that the species is very
concave beneath, and that the anus is placed very near the summit. He
states that it occurs near Caen, in “la couche a polypiers,”’ and near
Sandwich, in England—an evident mistake. ‘This possibly may be in-
tended for our typical clunicularis, but to such a description, unaccom-
panied by a figure, we can give no authority. In F. A. Romer’s
“ Versteinerungen des Nord-Deutschen Oolithen Gebirges ” (1836), a
Nucleolite is figured (pl. 1, f. 19,) and described under the name of

* Breyn (Schediasma de Echinis, 1732) has two species of his ‘ Echinobrissus,”
E. planior, the figure of which (t. vi. f. 1, 2) appears to be our var. «; and E. elatior,
which is in all probability a bad representation of our var. y.

4 BRITISH FOSSILS.

planatus. 'This Bronn identifies with scutata, Lamarck; but, though
evidently nearly allied, the depression is so great, and the anal furrow so
peculiarly shaped, that we cannot admit its identity. Bronn has also
referred with a query Goldfuss’s figure of Nucleolites cordatus (pl. 43,
f. 9,) to it. That figure would serve as an excellent representation of

some of the varieties of clunicularis, but as it is a highly magnified .
representation of a cretaceous fossil, it is probably distinct. ‘The most

important works on fossil urchins remain to be cited, viz., those of
Agassiz. The first part of this eminent naturalist’s work on the fossil
Echinodermata of Switzerland (1839) includes a monograph of the
Swiss Wucleolites (using the term in a very restricted sense), eight in
number, five of which are oolitic. Of these the first (Vucleolttes lati-
porus) appears to be a variety, more conical than usual, of WV. dimidiatus,
Phillips. JI have seen such a form in the collection of Mr. Tennant.
The second (Vucleolites micraulus) comes exceedingly near the same
species. The third (Wucleolites gracilis) is to my eye one of our com-
monest forms of WV. clunicularis. Nucleolites scutata, Lamarck, placed
fourth (distinguished from NV. scutatus, Goldfuss, which is unquestion-
ably dimidiatus), is our var. « in the form when passing into 6. The
fifth (JVucleolites major) is, judging from the figure, a slightly more
elongated and large variety of the same. The figures of all these are so
very excellent, that I do not hesitate in giving these opinions, especially
as the descriptions do not seem to contradict my conclusions. The later
work of Agassiz and Desor, “ Catalogue Raisonné des Echinides”
(1847), is not so satisfactory. The first fossil Nucleolites there given is
scutatus, Lamarck, with reference to the figure in the “ Echinodermes
Suisses.” The second is “ WV. clunicularis,” Phillips, the geology of
Yorkshire being the first citation; its synonyms are ‘“ Wucleolites Gold-
fussit,’” Desmoulins, and “ NMucleolites Sowerbyi,” Defrance. The latter
reference we have already seen to be next to worthless ; the former name
is stated by M. Agassiz himself to have been given by Desmoulins to the
IN. seutatus of Goldfuss (“ Ech. Suisses,” pl. 1, p. 45). Yet in this
catalogue the name of Goldfuss is quoted as a synonym of WV. micraulus,

Agassiz, (on which I have already remarked ; but it appears to be dimi- —

diatus, Phillips,) whilst démzdiatus is enumerated as a distinct species,
identical with Nucleolites paraplesius of Agassiz’s “ Catalogue Sys-
tématique.” Then comes JV. latiporus, Agassiz, with the note that it is
probably a variety of c/unicularis ; whereas, in the “ Echin. Suiss.,” p. 48,
it is compared with Goldfussii, and a new species, NV. Terquemi, said to
be near clunicularis also, whilst gracilis is retained as distinct. Further
on M. Desor has made a new species, “ WV. Thurmanni,” for a cornbrash
Nucleolites, “ assez voisin du LV. latiporus,” which we had been already
told was itself “peut-étre une vari¢té du NV. clunicularis.” We thus

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BRITISH FOSSILS. } 5

become involved in a labyrinth of names, several of which are unaccom-
panied by either descriptions or figures, a state of things more likely
to retard than to advance our paleontological studies. Lastly, im the
“ Annals of Natural History,” for December, 1848, three new British
oolitic Wucleolites are described by Mr. M‘Coy, under the names planu-
latus, pyramidalis, and equalis, all of which I cannot help surmising will
prove, on closer examination, but varieties of clunicularis. ‘The second,
NV. pyramidalis, from the cornbrash of Weymouth, has been identified
by Mr. M‘Coy with the figure on our plate, he having kindly replied to
- that effect to my inquiries on the subject. In his Paper he remarks,
“This resembles the WV. clunicularis (Smith, sp. Clypeus lobatus, Flem.)
4 in the long, deep, narrow posterior sulcus, extending quite from the
vertex, but is wider and more quadrate, the base having exactly the
form of the WV. scutatus, Lamarck ; from the latter it differs in the strong
sulcus uniting the pores, as in most of the genus, and from both species
it is distinguished by its pointed elevated apex, and the straight declivity
of the posterior side.” On this passage I would remark that, in the first
place, the name clunicularis is not given by Smith, whose figure (without
a name) probably represents dimidiatus ; that Clypeus lobatus, Fleming,
was a name given by that author to a species he considered distinct from
his elunicularis, “Smith,” as I have already shown; that “a strong
sulcus” unites the pores quite as much in the var. scutatus as in var.
pyramidalis ; and that the degree of elevation of the apex and declivity
of the posterior side varies not only in every variety, but in almost
every specimen, among the many I have examimed,* of all the varieties
of this variable species.

Description.—Outline suborbicular, with a tendency to quadrate,
broadening out slightly, and more or less bilobed posteriorly, rounded
anteriorly. Back more or less elevated, varying from subdepressed
(var. «) to subconical (var. y), but exhibitmg all mtermediate degrees
of convexity. ‘The true apex is invariably the highest point, from which
the sides decline with greater or less steepness, and anteriorly with more
or less straightness. The apex is always excentric, inclinmg towards
the anterior extremity. The portion of the back in front of the apex is
about one-sixth shorter than that behind it. The anal furrow reaches
quite to the apex, in some specimens slightly indenting it. It is always
of a lanceolate-acuminate form ; lanceolate to the upper part, the anus
then narrowing into a prolonged and shallower, but still strongly marked
groove. ‘The anus is very deep sided, and the bounding walls of the
groove diverge slightly downwards. ‘The lower part of the groove,
behind the anus, is very much depressed and well defined. The am-
bulacra are petaloid with subparallel sides, the spaces between the rows ,

4

* Through the kind co-operation of Mr. Woodward, ve Nucleolites of the British
Museum were laid out for my inspection.

6 BRITISH FOSSILS.

of pores forming each ambulacrum varying slightly in width in different
specimens; those of the two posterior ambulacra widest. ‘The upper
part of the latter run close in contact and partly over the edge of the

superior or narrow portion of the anal groove. ‘The furrow uniting the ~

pairs of pores varies in depth im different examples. ‘The number of
conspicuous pores in each row dorsally is from 36 to 40. The spaces

separating the grooves linking the pairs of pores are minutely granu-

lated. ‘The whole surface of the dorsal, lateral, and inferior ambulacral
and interambulacral plates is covered with thickly-set mmute spiniferous
tubercles, lodged in moniliform depressions, the interspaces minutely
sranulated. The ovarian plates are well covered with similar granules,
no tubercles. ‘The ovarian pores are conspicuous, except the posterior
one, which is obsolete. Very distinct holes for the ocelli are seen at the
summits of the ambulacral avenues. The ventral surface is more or
less concave, most so in the pyramidal varieties. ‘The ambulacra radiate
in depressed furrows from the mouth, becoming shallower towards the
margin. ‘The mouth is more eccentric, and nearer to the anterior
margin than the apex. The tubercles on the ventral surface are rather
more scattered than on the dorsal.

Comparative Dimensions of average Specimens of each of the three varieties

(all of which, however, insensibly pass into each other), in inches and —

twelfths.
Length, 60). 6 ks 16 | OF lh
Breadth 12) 010 ee
Apex to anterior margin. of | 08 | 0%
Mouth to anterior margin O07, | OF | OF
Length of analfurrow . . . of | 0% | 03%
Breadth of anal furrow at anus, 02 | 02 | 08

British Locahties and Geological Range.—Inrerior Ooxire, Stroud
(B. M.). Great Ooxitre, Minchinhampton (B.M.). Cirencester (S.
P. Woodward). Cornprasu, Yorkshire (Phillips). Abundant in corn-
brash of Dorset (Bristow, Gapper). Chippenham, small gray variety
(S. P. Woodward). Northampton (B. M.).

Foreign Distribution.— (Extracted from the catalogue of Agassiz and
Desor.) “Oxford. d’Alencon, Courgains (Sarthe), Calc. a Polypiers
de Ranville, Coulie—var. minor. Forest Marble de Chatelcensoir.”
Form datiporus, ‘“ Cornbrash de Metingen, Maiche.” Form gracilis,
“ Qol. Ferrug. de Durrenast (Jura Soleurois).”

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BRITISH FOSSILS. "

DESCRIPTION OF THE PLATE.

Fig. 1, var. y, dorsal view. Fig. 2, ventral surface. Fig. 3, profile. Fig. 4, diagram
of the dorsal structure. Fig. 5, apical disk of ovarian and ocular plates. Fig. 6, portion
of surface of a plate magnified. Fig. 7, arrangement of the pores in the ambulacral
avenues.

Norte on British Wucleolites allied to WV. clunicularis.

Under the generic appellation Nucleolites I include all the members of the family Cas-
sidulide (Agassiz) with petaloid ambulacra and a supra-marginal anus, and under the
subgenus Nucleolites those members of the genus so called, in which the anus is placed
high up within a deep sulcus. To the orbicular species of this division the generic term
Clypeus (Klein) is restricted in the arrangement of Agassiz, who styles those only
Nucleolites in which the shape is more or less angularly subquadrate. He further dis-
tinguishes between the two sections by the presence of tubercles or prominences around
the mouth in the former, and their absence im the latter, a distinction which does not hold
good, since in Vucleolites lacunosus the oral prominences are more strongly marked than
in Clypeus Hugii. There is, moreover, a gradual progression of form from the almost
completely orbicular outline of Clypeus sinuatus to the ovate contour of Nucleolites
lucunosus.

Though the name Clypeus was used by Klein before that of Mucleolites, the latter is
preferred because proposed as a definite generic appellation by Lamarck.

Our British Nucleolites are all either oolitic or cretaceous. In the species of the older
secondary rocks we find a structure of the ambulacral pores which distinguishes them
easily on close examination, however nearly they may resemble at first glance, from
those of the upper secondaries. The former have the external series of pairs of pores in
each ambulacrum more or less widened and marked by conspicuous connecting furrows ;
the latter have the pairs of pores in the outer series closely set together, and the furrows
consequently indistinct. The widening of the avenues by poriferous sulci is most conspi-
cuously exhibited in Nucleolites sinuatus, and in this species and its allies the pores of the
ambulacra near the mouth have a tendency to fall into ranks of several pairs.

The British Nucleolites known to me are the following ;—

A. SPECIES OF THE OoLiTic TYPE.

1. Nucleolites clunicularis (including scutatus or depressus, and pyramidatus), as defined
in the preceding account of the species.

2. Nucleolites dimidiatus (Sp.), Phillips, Geol. of Yorkshire, vol. i., pl. 3, f. 16. Coral-
line Oolite.

NN. ambitu ovato, antice rotundato, postice bilobato ; dorso convexo, apice centralt, vertice
subcentrali, postice tumido; ambulacris anguste lanceolatis ; sulco anali profundo, ovato,
obtuso, superne abbreviato, lobis posterioribus tumidis ; ventre plus minusve concavo.

This species rarely exceeds an inch in length, and varies greatly in the convexity of its
upper surface. The ovate anal sulcus, reaching about two-thirds of the distance betwe n
the posterior margin and the true summit, conspicuously distinguishes it from clunicularis,
with which it was confounded before being distinguished by Phillips.

It occurs in both coral rag and cornbrash, but especially in the former.

3. LNucleolites orbicularis (Sp.), Phillips, Geol. of Yorkshire, vol. i., pl. 7, fig. 3.

NV. ambitu orbiculari, lateribus tumidis, dorso convexo, apice vertice-que centrali, ambu-
lacris lanceolatis, ad apices distantibus ; sulco anali oblongo, obtuso, ad verticem approxt-
mato, lobis posterioribus obsoletis ; ventre concavo, ore subcentrali.

Usual diameter about an inch and a quarter. Cornbrash of Wilts and Yorkshire. Coral
rag of Calne. The ocular plates are more apart, and the vertex consequently broader in
this than in any other British JVuc/leolite. .

4. Nucleolites Hugii, Agassiz, Echin. Suiss. vol. i., p. 35, t. 5. figs. 1-3.

8 BRITISH FOSSILS.

NV. ambitu suborbiculari, subsinuato, lateribus decliventibus ; dorso convexo apice sub-
excentrali, supra-anali, vertice excentrico ; ambulacris lanceolatis, ad apices approximatis ;
sulco anali oblongo, obtuso, lato, brevi, ab vertice disiante; lobis posterioribus obsoletis ;
ventre concavo, ore valde excentrico.

- About the size of the last. Inferior oolite of Stroud (Mr. J. G. Lowe), communicated
by Mr. Woodward.

5. Nucleolites sinuatus (Sp.), Leske. Parkinson, Org. Rem., vol. iii., pl. 2, fig. 1. 2.
Galerites patella, Lamarck (? of Agassiz, E-chin. Suisses).

NV. ambitu orbiculari, lateribus decliventibus ; dorso subdepresso, apice vertice-que vix
centrali; ambulacris late lunceolatis, ad apices approximatis; suleo anali lanceolato
acuminato, in verticem prolongato, profundo, lateribus abruptis ; lobis posterioribus nullis ;
ventre concavo.

Two inches and a half, or more, in diameter. Cornbrash, great oolite, inferior oolite,
and coralline oolite in many places. "

In the “ Catalogue Raisonné des Echinides,” of Agassiz and Desor, there is a Clypeus
rimosus, ‘‘ Espéce plate, discoide 4 ambulacres costules,” evidently nearly allied to this
species, and said to be from oolitic strata in Gloucestershire; it is in the collection of M.
Deluc. :

6. Nucleolites emarginatus (Sp.), Phillips, Geol. of Yorkshire, vol. i., t.3.f£18. }

NN. ambitu orbiculari, lateribus decliventibus ; dorso subdepresso, apice vertice-que vix ‘
centrali ; ambulacris late lanceolatis, ad apices approximatis, sulco anali brevissimo, obtuso, ;

ab vertice valde distante ; lobis posterioribus obsoletis. :
As large as the last species. In the coralline oolite of Yorkshire. d

Besides the above-named species, there is a small Nucleolite from the great oolite of q
Harleston, apparently distinct, allied to clunicularis. In the British Museum. ;

In the same collection there is also a small species from the inferior oolite of Stroud, ,
which is probably new. See also Mr. M‘Coy’s paper in Ann. N. H. 5rd ser. vol. ii, p. 417. :

B. Sprcres or THE CRETACEOUS TYPE.

7. Nucleolites cordatus, Goldfuss, Pet. Germ., pl. 43, fig. 9. ‘

NV. ambitu ovato-rotundo, untice rotundato postice vizx bilobato ; dorso convexo, apice
vertice-que centralt ; ambulacris anguste lanceolatis ; sulco anali profundo, late-lanceolato,
superne subacuminato, lobis posterioribus tumidiusculis.

Upper green sand of Wiltshire. In Mr. Tennant’s collection. The specimen agrees in
form, tumidity, and size, with that figured by Goldfuss. It is not so distinctly lobed pos- i
teriorly, and the anal furrow is not so narrow or acuminate.

8. Nucleolites lacunosus, Goldfuss, Pet. Germ., t. 43, fig. 8. ‘

LV. ambitu ovato, antice obtuso, postice subquadrato, subtruncato, lateribus subcompressis ;— t
dorso convexo, apice subcentrali seu supra-anali, vertice excentrico ; ambulacris lanceolatis,
lateribus subrectis ; sulco anali profundo, brevi, oblongo, abrupte declivente, lobis postertoribus
subdepressis ; ventre excavato.

Specimens are usually about half an inch in length. Common in the upper green sand
of Warminster (Survey Collections),

9. Nucleolites Morristi, Forbes; Cassidulus lapis cancri, Morris, Cat. p. 49 (not of
Goldfuss).

N. ambitu oblongo, antice postice-que obtuso, lateribus’ depressis, dorso depresso, apice
subcentrali, vertice centrali ; ambulacris linearibus ; sulco anali profundo, brevissimo, sub-
triangulari ; lobis posterioribus nullis ; ventre excavato.

See ee a a Shee

Waa

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a

cig

:

Large specimens are half an inch in length. Upper green sand of Warminster and d
Blackdown (Mus. Tennant). 2
; hk. Forses. é
April, 1849. ?

Geological Survey of the United Kingdom.

FEGIGIGG >

NINCLEOLITES CCATGPYGUS) > CARIN BITS

W.H.Baiky del! {.lorbes direx*

DECADE PL 10:

.

NUCLEOLITES

(Cretaceous)

Munster

:
.
;

a ae ee et

e
3
A
2
4

BRITISH FOSSILS.

DecapE I. Puate X.

———

NUCLEOLITES (CATOPYGUS) CARINATUS.

{Genus NUCLEOLITES. Lamarck. (Sub-kingdom Radiata. Class Fichinodermata.
Order Echinide. Family Clypeasteride.) Body orbicular, oval, or cordate, more or less
tumid, sometimes much depressed; ambulacra dorsally petaloid; anus supra-marginal ;
mouth sub-central. | ;

[Sub-genus Catopygus. Outline narrowing anteriorly; body truncated posteriorly, with
the anus on the superior surface of the truncation. Tubercles around mouth conspicuous. ]

Synonyms. Nucleolites carinatus, Goup¥Fuss, Pet. Germ., p. 142, pl.
43, f.4,a-c. Catopygus carinatus, Acassiz, Cat. Syst., p. 4. AGASSIZ
and Drsor, Cat. Rais. des Echin., Ann. Se. Nat.; 3rd ser., vol. vii., p. 157.
Brown, Lethea Geog., p. 6138; Index Paleont., p. 249. Morris, Cat.,
p. 49.

Diaenosis. NV. (Catopygus) ambitu ovali seu subrotundo, postice plus
minusve dilatato; dorso convexo, prope anum obsolete carinato ; apice excen-
trico, vertice post apicem; ambulacris lineari-lanceolatis ; extremitate anali
truncata supra anum prominente, subapiculata, ano suboblongo in parte
superiort posito ; ventre convextusculo.

Var. a. ovato-rotunda, dorso tumide.—Nucleolites carinatus, GOLDFUSS,
Pet. Germ., pl. 43, f. 4, a-e.

Var. (3. ovata, dorso antice declivente.—Nucleolites columbarius, D’ Ar-
cHtac, Mem. Geol. Soc. France, 2nd ser., vol. ii., pl. 13, fig. 3, a, b,c?

Var. y. oblonga.

Var. 6. subglobosa.

The clear and distinct history of this fossil urchin dates from the
excellent figure and description given by Goldfuss in the Petrefacta
Germanica, where the Nucleolites columbaria of Lamarck is cited as a |
questionable synonym, and the Echinites pyriformis of Parkinson re-
ferred to without mark of doubt. Parkinson’s species (Organic Remains,
y. ii. pl. 3, f. 6), however, was from the Maestricht beds, and was rightly
identified by him with the Echinites pyriformis of Leske (t. 44, f. 7 and
51, f. 5, 6), which circumstance seems to have escaped Goldfuss, who
quotes the figures in Leske for his Nucleolites pyriformis (Pet. Germ.,
p. 141, t. 43, f. 7, a—f.) A comparison of specimens of the Maes-
tricht fossils with ours has confirmed their distinctness; the anus in the

ie ac,'| | L

4 BRITISH FOSSILS.

former, as indeed it is represented by both Leske and Parkinson, being
much nearer the posterior margin, and the ambulacra much narrower
than in WN. carinatus. The Nucleolites columbaria of Lamarck was a
species very insufficiently described by that author, who cites no figure,
and mentions that it is found as fossil in the environs of Mons. In

Count D’Archiac’s valuable report on the fossils of the Tourtia, a —

remarkable cretaceous conglomerate found in Hainault and a part of

French Flanders, a detailed and most excellent description is given of

the Nucleolites columbarius of Lamarck, which is there distinguished
from the Nucleolites carinatus of Goldfuss, from which it is stated to
differ in its general form being more elongated, more depressed, and
consequently less globular. Excellent figures are at the same time
given, which, however, so closely resemble one of the commonest forms
of our English carinatus, and certainly one not distinct, that I do not
venture to separate the species; nor does the accompanying descrip-
tion contradict their identification. One point only in the figure seems
to differ ; the upper margin of the anus is not so prominent in the
French specimens as in ours. M. Desmoulins is quoted by M. D’Archiac
as having identified the species of Goldfuss with that of Lamarck. In
the “Catalogue Raisonné des Echinides,’”’ the Catopyyus carinatus is
regarded as distinct from the C. columbarius, and the figure of D’ Archiae
is cited for the latter. Under the synonyms of the former, the name
“ Nucleolites britanna, Defrance,” is cited, and as a variety, “ minor :
Nucleolites ovulum, Defrance.” Nucleolites (Catopygus) carinatus was
first enumerated as a British species by Morris in the “ Catalogue of
British Fossils.” In the “Index Paleontologicus,’’ Bronn cites JV.
columbaria, Lamarck, as a questionable synonym of carinatus, retainmg
at the same time Catopygus columbarius of Agassiz, for which he refers
to D’Archiac’s figure and description as a distinct species. In England,
so far as I have seen at least, we have only the one species of this sec-
tion of Nucleolites, and that one so variable in its outline that we are
naturally led to suppose too many species have been made out of it on
the Continent.

Description —Outline varying from ovate to subrotund, always more
or less widening out posteriorly, least so in vars. y and 6. Back tumid,
varying in degree of elevation; in some specimens, especially of var. ,
subdepressed and declining anteriorly, in others subconic and much
elevated in the centre, when the true apex is almost at the same spot
with the highest point ; the latter is usually, however, behind the ovarian
disk. ‘The apex is always more inclined to the front than to the posterior
extremity. The sides, in all the varieties among British examples, are
rounded with a very slight degree of compression in all varieties. The
posterior extremity is truncated more or less abruptly. A more or less

Taete FS ee a TO ee a a. 2M Ee

BRITISH FOSSILS. 3

developed obtuse carination runs down the posterior ambulacral space,
with a curvature to a culminating point forming the superior margin of
the anus, and part of a prominent, and in some specimens apiculated,
arch over that aperture. ‘The anus itself is vertically oval; it varies in
size in different specimens, but is always small in proportion to the
body ; it occupies the upper portion of an obsolete and obscure groove,
which vanishes as it approaches the posterior: margin. The anus is
always nearer the posterior margin than the apex. ‘The ambulacra are
narrowly lanceolate and faintly petaloid; they preserve the same pro-

portions in all the varieties. They are nearly equidistant from each

other at their summits. ‘The number of pairs of pores in each row is
nearly equal in all, and varies from 28 to 30 in well-grown specimens.
The outer pores in each pair are elongated and oblique, and the two
pores are connected by a groove more or less distinct in different
examples. The ridges separating the grooves are rounded and smooth.
The ambulacral plates between the rows of pores are narrow, small, and
very numerous, but become much larger and broader suddenly, as the
ambulacra vanish. Each of these broader ambulacral plates has a pair
of minute pores, seeming to the eye as single, at its inferior and exterior

angle. The interambulacral plates are ample and oblong. Both sets

of plates are covered by minute moniliform tubercles, interspersed with
still smaller granules, and only to he distinctly seen in exceedingly well-
preserved specimens. There are four perforated ovarian plates, and
five oculars, with very distimct eye-pores. The two anterior pairs of
ovarian pores are placed nearer together than the two posterior ones, in
consequence of the anterior ambulacrum, which is narrower than the
others, only separating the former, whereas the latter are separated by
the summits of the two postero-lateral ambulacra. In consequence,
also, of the two antero-lateral ambulacra being rather broader than any
of the others, the lateral distance between each pair of ovarian pores is
greater than the distance between the frontal pair. ‘The centre of the
ovarian disk is occupied by a distinctly marked punctated madreporiform
tubercle. ‘The ventral surface is nearly plain, or very slightly convex.
The tubercles on it are larger than those of the dorsal. The mouth is
eccentric in the direction of the anterior extremity. It is pentagonal,
and surrounded by five prominent tubercles, which terminate the inferior
interambulacral spaces. ‘These tubercles are curiously granulated in a
reticulate fashion. From the mouth radiate ten short petaloid ambu-
lacra, constructed like those of the dorsal surface.

The following table exhibits the comparative dimensions of six speci-
mens, five of which come from the same locality (green sand of War-

_ minster), and one (No. 4) from the junction beds of the green sand and

chalk marl at Maiden Bradley, Wiltshire, in which the majority of

4 BRITISH FOSSILS.

specimens exhibit the dimensions of No. 8. Of the six, Nos. 1, 2, and 4
may be regarded as belonging to form 6, No. 3 to form @, the most
common variety, No. 5 to var. y, and No. 6 to var. 0. These different
forms have really scarcely any claim to the rank of varieties, for every
degree of intermediate shape is exhibited by specimens collected in the
same localities.

a L 2 3 4 5 6
Lenpthe ) she) a Oty Are 5 a| o¢
Breadth. . |. |: O18 | OH} +08 & | 08% | OF
Height: 2) 0) 24 O28} O4750 6 64 Oe

British Localities and Geological Range-—UPrEeR GREEN sAND—
Warminster, Wiltshire (Survey Collections); Chute Farm, Wiltshire ;
Hythe, Kent (Morris). Junction beds of UPPER GREEN SAND and CHALK
MARL, Maiden Bradley, Wiltshire (Bristow), (Survey Collections). -
Foreign Distribution.—Upper green sand of France and Germany.
C. columbarius, as defined by D’Archiac, is from the Gault of Mans, -
Coulaines, and Fouras. , :

DESCRIPTION OF THE PLATE.

Fig. 1. Specimen of typical form seen from above. Fig. 2. Lateral view. Fig. 3.
Posterior view. Fig. 4. Diagram of a specimen of form £, seen from above. Fig. 5. From
beneath. Fig. 6. Posterior view. Fig. 7. Diagram of relative positions of ovarian and
ocular pores, and summits of the ambulacra. Fig. 8. Arrangement of pores in each
ambulacral series. |

! oe ForBgs.
April, 1849. :

5

Pt ent. ote UL

q MEMOIRS

OF THE

GEOLOGICAL SURVEY

OF

THE UNITED KINGDOM.

Figures ond Hescrigtions

ILLUSTRATIVE OF

BRITISH ORGANIC REMAINS

DECADE II.

erTwrnrr~rrrreeeseee aeeeoeoeeererereeenwrrees> mnes

PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY.

LONDON:

PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:

a LONGMAN, BROWN, GREEN, AND LONGMANS.
1849.

NOTICE

‘PaLmonvotocican researches forming so essential a part of geological
investigations, such as those now in progress by the Geological Survey
of the United Kingdom, the accompanying plates and descriptions of
British Fossils have been prepared as part of the Geological Memoirs.
They constitute a needful portion of the publications of the Geological
Survey, and are taken from specimens in the public collections, or lent
to the Survey by those anxious to advance this branch of the public
service. Although numerous drawings had previously been made, and
engravings from them considerably advanced, it was not thought expe-
dient to commence their publication until the large collections of the
Survey could be well examined, which a want of the needful space
has, until the present time, considerably retarded. ‘This impediment
to progress is now being removed, and when the collections can be
properly displayed in the New Museum of Practical Geology, in
Jermyn Street, it is hoped that the public will have an opportunity
of gradually obtaining, in a convenient manner and at small cost, a
work illustrating some of the more important forms of animal and
egetable life there prese rved, and which have been entombed during

the lapse of geological time in the area occupied by the British islands.

The plan proposed to be followed in the work, of which the two

Decades now published form a part, is as follows :—

To figure in elaborate detail, as completely as possible, a selection of

fossils, illustrative of the genera and more remarkable species of all

1V NOTICE.

classes of animals and plants the remains of which are contained in
British rocks ; to select especially such as require an amount of illus-
tration which, to be carried out by private enterprise, would require
a large outlay of money, with little prospect of a return, and a long
time to accomplish, but which, by means of the staff and appliances”
necessarily employed on the Geological Survey, can be effected at small
cost, and with a rapidity demanded by the publication of the Maps and
Memoirs of the Survey; thus, it is hoped, affording an aid to those
engaged in the sciences with which this Work is connected, that they
might not otherwise have possessed, and which may materially promote

the progress of individual research.

H. T. De xa Becue, ©

Director-General.

Geological Survey Office,
7 18th July, 1849.

BRITISH FOSSILS.

DECADE THE SECOND

TueE second Decade of representations of British Fossils contains illus-
trations of the genera and species of ‘Trilobites.

These remarkable animals, belonging to a group of Crustacea, of
which we find no traces in strata formed subsequently to the Paleozoic
period, were first observed in British rocks, Nevertheless, the investi-
gation of those species found in our country is as yet far from complete.
Our recorded knowledge of them is chiefly contained in the works of
Sir Roderick Murchison and of Lieut.-Colonel Portlock. In the
“ Silurian System,” only are figures to be found of our commoner spe-
cies, and in the “ Report on the Geology of Londonderry, Tyrone, and
Fermanagh,” is the only systematic dissertation on their arrangement,
which has yet been published in Britain.

During the progress of the Geological Survey through the Silurian
districts of Wales and the bordering counties, much new and import-
ant material has been collected towards the elucidation of the structure,
affinities, and distribution of Trilobites. The following figures and de-
scriptions consequently contain much that has not been before noticed
respecting these animals, and new light will be found thrown on several
features of their organization.

The Trilobites selected as subjects for this Decade are species of the
genera Phacops, Illenus, Asaphus, Ogygia, Calymene, and Ampyz.
Some of them are renowned and characteristic forms, such as Phacops
(Dalmannia) caudatus, Ilenus (Bumastus) Barriensis, Asaphus ty-
rannus, and Ogygia Buchii, which, whilst they furnish excellent typical
figures illustrating generic or sub-generic groups, acquire an additional

[ 11. | 7‘

vi BRITISH FOSSILS.

value on account of the abundant details of structure, which, through
our extensive collections, we are enabled to delineate; others, as
Ogygia Portlockit, Calymene tuberculosa, and Ampyx nudus, are critical
species, the history of which has been hitherto imperfectly known; and
a third class consists of entirely new forms, such as Illenus Davisit
and Olenus micrurus ; the last mentioned trilobite has great interest,
having been found in the most ancient fossiliferous strata of the Silurian
System, whilst at the same time it constitutes a good representative of
the numerous forms of the genus Olenus, which occur in the oldest
rocks of the Continent.

The descriptions of all the species, with the exception of Ampyx nudus,
have been drawn up by Mr. Salter, whose attention has for some time
been specially directed to Trilobites.

Illustrations of the other British genera of Trilobites are in pre-
paration. :
EDWARD ForBEs.

July, 1849.

DECADE 2. Pt... |

PEAGCOPS ©
(Silurian )

Brinn.

PHACOPS (DALMANNIA) caupatus

BRITISH FO: 5S: PL:

Decapve II. Puare I.

eee

PHACOPS CAUDATUS.

[Genus PHACOPS. Emmericn. (Sub-kingdom Articulata. Class Crustacea. Order

Entomostraca. Family Trilobite.) Eyes largely facetted; facial suture ending on the
outer margin ; thorax 11 jointed.]
_ [Sub-genus Dalmannia. Depressed ; pleure pointed and bent back ata distant fulcrum ;
glabella not inflated, with three lateral lobes; facial suture within the edge in front; head
angles long-spined ; hypostome obtusely pointed ; tail with a many-jointed axis, and
without lateral spines. |

Diaenosis. P. (Dalmannia) fronte angulato; oculis maximis pyra-
midatis, e sulco glabellari basali ad tertium et supra extensis; pleuris
recurvis, fulero ad dimidium ; caude apice mucronato, axi 11-12 annulato,
eostis lateralibus 7, rarius 6, arcuatis, duplicatis, ad marginem levem
abrupte terminatis.

Synwonyms.—Van. a. Vulgaris.—Fronte capitis angulato ; apice caude
brevimucronato.— Plate L, figs. 1 to 12, and fig. 15.

Trilobus caudatus, Brunnicu (1781), Kjobenh. Sellsk. Skrifter. Nye
Samml., vol. i., p. 392. Asaphus caud., BRONGNIART (1822), Crust. Foss.,
cDigerae & 4 (not 3, f.9). TZrilob. caud., ScHLOTHEIM (1823), Nachtrage,
35. ll. Asaphus-caud., Daumawn (1826), Palead., t. 2, f. 4. GREEN
(1832), Monogr. Trilob. N. Amer., cast 17. Buckuanp (1836), Bridgw.
Treat., pl. XLV., f.9-11. Murcnison (1887), Sil. Syst., pl. 7, fig. 8 a.
A. tuberculato-caudatus, ib., fig. 8b. A. caud. and A. tuberculato-caud.,
Mitne Epwarps (1840), Crust. 3, 308. P. caud., BuRMEISTER, Org.
Tril., t. 4, f. 9. Ray edition (1846).

Var. 8. Longicaudatus.—Plate I., figs. 18, 14.— Axi angustiori, fronte
capitis cauddque longimucronatis.

Trilobite with caudal process, PARKINSON (1811), Organic Remains, vol.
iii., t.17, f. 17. Asaphus longicaudatus, Murcuison, Sil. Syst., pl. 14,
figs. 11 to 14. Miztne Epwarps, Crust. 3, 308. Phacops mucronatus,
Burmeister, Org. Tril., 113 (exclude all synonyms except Murch.). Ray
edit., 95. [ Phac. longicaud., Rovauut (1847), Bull. Soc. Geol. Fr., 2nd
Ser., a 320 ?].

Description of Var. «.—Four or five inches long; ovate; length as
to width varying from 10°6 to 84:6; thorax longer than either head or

tail; the latter about equal to the head, excluding the produced mucro ;
Bir. i. | 7 on

2 BRITISH FOSSILS.

axis of the whole body considerably narrower than the sides. Head
finely granular all over, semicircular, without the slightly produced
snout, or the long, stout, posterior horns, which are broad at the base,
and reach the seventh or eighth thoracic rmg. Glabella coarsely
tubercular, widened above, more than one-third the width of head, the
forehead lobe a transverse rhomb, separated by deep, broad, oblique
furrows which nearly meet, from the upper side lobes; three lateral
lobes and neck lobe all nearly equal in width, and together equalling
the forehead lobe; the first and second lie straight across, and leave but
a narrow ridge down the middle: strong axal furrows separate the
glabella from the triangular cheeks, of the surface of which the large
pyramidal eyes occupy a variable proportion; a lunate depression
surrounds their outer edge, and this is sometimes extended over more
than half the width of the cheek, sometimes barely half, giving a con-
siderable difference in appearance. The length of the eye, which is

sharply curved, is uniformly from the first basal furrow te the middle of |

the upper one; eyelid with a deep concentric groove; lentiferous sur-
face considerably broader forwards, lenses about 240*, 8 or 10 in a
vertical row. In the cast, which represents the crystalline layer behind
the lenses, the surface is covered with close-set, circular pits, with
narrow distinct borders (Fig. 5) ; in these hollows the moderately convex
lenses are set, and in most specimens we see no cornea over them.
In two perfectly preserved eyes from Ledbury (Fig. 4), the cornea is,
however, present, and contrary to Professor Burmeister’s prediction, is
distinctly convex over each lens, the intermediate portions beimg orna-
mented with tubercles and granules, so as to leave no doubt of its
being the true exterior ; it is, too, continuous with the other portions of
the preserved shell. The cornea does not rise, as in some other species,
into elevated ridges between the lenses, but is fiat, or ‘in other specimens
(Fig. 6), it sks down between them. In Fig. 4 a lens or two is seen
to be undeveloped and very small, among other perfect ones. The
facial suture exactly circumscribes the glabella in front, falls perpen-
dicularly to the eye, and arches outwards and upwards from its lower
angle to the outer margin of the head, on the lower face of which it
extends along the margin further back than on the upper surface (see
Fig. 10a). The cheek-pieces are united in one (as in all the genus)
across the front, and there is no extra piece inserted between them above
the hypostome. The latter (Fig. 3) is parabolic, obtusely pointed, the
sides a little waved, and the base of attachment extended ; a transverse

furrow, within the tip, is connected with a marginal longitudinal one on —

each side, a pair of lateral strong indentations indicate a second. furrow

* Buckland, Bridgw. Treat., p. 399, reckons 400, This was probably intended for both —

eyes.

NE ee eS ee ee Lee Oe

= Se OS RAT er ma RG CRY

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BRITISH FOSSILS. 3

above. Round the head a strong furrow separates the broad margin,
‘stops at the base of the spines, and there nearly meets the equally
strong neck furrow, which is arched down at its end. The margin in
‘front more or less produced into an obtuse point. Thorax with the
central lobe not separated by any strong furrow from the pleura, which,
in English specimens, are half as wide again as the axis; the axis is
a little fusiform, not broader than the base of the glabella, and either
has the rings smooth, tubercled at their outer edges, or with two tuber-
cles on the central prominent part :—all these variations occur on the
.same thorax. ‘The front pleure are flat for the first half, then gently
curved down, and a little back, at the obscure fulcrum ; they are divided
by a moderately strong curved furrow for most of the length, and their
edge sharpened anteriorly (the flat surface not crossing the furrow as in
true Phacops) for bending. ‘The extremities are truncate, and pointed at
the hinder corner ; posterior pleure with the fulcrum at less than half,
much more curved back, and strongly pointed, overlapping the upper
corners of the tail. Whole surface of thorax finely granular. Tail
with the sides meeting below at nearly a right angle, and produced
_more or less to a sharp point beyond this; axis not much raised, and
gently tapering, ending a little abruptly at some distance from the
point; it has 11 or 12 ribs, which are accidentally tubercular, like the
thorax, sometimes much so; the sides have six, seven, or sometimes
eight narrow ribs, strongly arched down at their ends, where they abut
_ suddenly on the smooth margin; each rib is sharply defined behind, and
duplicated on its forward edge by a fine rib, running parallel to it
along its whole length. ‘The number of the ribs on the tail appears to
be as great in the young animal, judging from the beautiful specimen,
Fig. 7, from Mr. J. Gray’s collection.

Variations.—The tail margin varies much in width. In fig. 15 it is
very narrow, and the apex little produced. Most of the specimens of
var. 2, in shale or mud (Fig. 11), have the axis of the head and tail
narrower than those in limestone (Fig. 12), and the tail itself broader
and more mucronate. From Ludlow we have specimens of this form,
with all degrees of attenuation in the mucro. The larger head of
var. 6 (Fig. 14), has the outer margin more expanded than in any lime-
Stone one yet seen.

Sex.—Some differences are very observable between individuals of
this species, as well as of other species and genera, which are possibly
referable to sex. We find the male in insects distinguished by large and
prominent eyes, extra length of spines, and narrowness or depression of
the body ; the latter character is sexual in the crustacea. It is natural
to look for some sexual distinctions in animals with such marked

_ _ forms as trilobites have, but an examination of Serolis, the external

4 BRITISH FOSSILS.

characters of which, at least, imitate best those of trilobites, does not
help out the case. The differences pointed out there by Milne Edwards
and Audouin reside in the feet and appendages, not in any general
shape, prominence of eyes, or sculpture, and we can, therefore, only
surmise from general analogy, that certain individuals with the glabella
flattened so as to leave the eyes projecting, the body more depressed,

and the spines of the front and sides of the head, or the mucro of the

tail more developed, may be males; while greater general convexity,
more convex glabella rising nearly as high as the eyes, and a tail not
attenuated into the mucro, but simply pointed, may mark the other sex.
Fig. 1 we think a female, and in this the eyes seen in front view (Fig. 1 a)
do not rise much above the glabella, and the body is convex, the tail
simply pointed ; but in others the glabella is depressed, especially be-
hind, and the front produced. In Fig. 9, supposed to be a male, the pro-
duced angular front is shown. Fig. 8 shows the great length the spines
of the head sometimes assume.

If P. longicaudatus, our var. 6, be identical with this species, and it
differs in nothing except the greater development of the processes, the
probability of this difference beg sexual is confirmed, for there occur
in the same slabs individuals exactly alike, some with long se ae to
head and tail, and others without them.

Affinities—But one European species is sufficiently like ours to
render a close comparison necessary. We refer to the Asaphus mucro-
natus (Brongn.), which Professor Burmeister identifies with our var. 6 ;
however, he had not seen specimens, and we have them before us. The
head of that is regularly convex, the axal and glabellar furrows not

deep, the eyes placed further forwards, the margin narrow. ‘The tail '

is like, but the ribs do not imbricate posteriorly, and the intermediate
furrow divides them more equally. ‘The mucro, too, is recurved, as in
P. proevus, with which, without being identical, it is closely allied.
Asaph. pleuroptyx (Green, cast 18), has 11 or 12 lateral ribs to the tail,
extending below the very narrow axis; but with P. dimulurus (Green,
cast 16), from the Niagara shale, there are so many points of resem-
blance, that we can hardly persuade ourselves they are distinct. Speci-
mens in the cabinets of Sir C. Lyell and Dr. Bigsby show that the form
ismore elongate, the pleure shorter, the glabella contracted at the base,
and the eyes perhaps smaller ; the tail narrow, its lateral ribs faint and
but little arched, while the extremity of the axis is more prominent.
The head wants the strong marginal furrow, and the posterior spines
extend but a little way down (to the fifth rib, Hall). While avoiding
the risk of a doubtful synonym, we cannot value these mere proportional
characters as specific, and believe that a larger series will unite the
above and P. Wetherilli (Green, cast 20), to the English species.

ESSE ES Se

Dit,
\

Rte Sale ES

Be = eee Saeee

BRITISH FOSSILS. 5

‘

History—When Brongniart made the first scientific attempt to

classify trilobites, his genus Asaphus confessedly stood as debateable

land between Calymene and Ogygia, but he clearly pointed out that
the type of the genus, when restricted, should be Asaphus cornigerus,
a species possessing smooth eyes and eight joints to the thorax. The

- characters ‘‘ Tubercules oculiformes reticules”’ were drawn from the

present species, and the figures also from Dudley specimens. Dalman
followed, without much improving this classification, but Quenstedt, in
1837, clearly separated the group of trilobites with facetted eyes,
(meaning thereby with large prominent facets), and Hmmerich named it

-Phacops. In the treatise on the “ Morphology, Classification, &c., of

Trilobites,” published 1845, in Leonhard and Bronn’s “ Neues Jahr-
buch,” Emmerich pointed out the subdivision Dalmannia, making Ph.
caudatus (Briimn.), its type. Burmeister, however, has thought fit to
retain all under Phacops, and the characters of one group pass so gra-
dually into those of another, that we prefer following his plan, though in
the Memoirs of the Geol. Survey, just published, we have adopted the
genus (vol. ii., part 1, page 337.) Sir R. I. Murchison, in 1837, gave
figures of the ordinary and the tuberculated forms, and there was quite
sufficient to justify him inmaking the var. longicaudatus a species.
After observation of many intermediate forms, however, we unite them
without much doubt of the propriety of so doing. Green, in 1832, did
some service by publishing his casts, and he would have done better had
he not permitted them to be carved to make them more plain. Milne
Edwards adopted the previously published species in his excellent work
on recent crustacea. Professor Burmeister confused the synonyms of
this species, by too hastily uniting P. mucronatus with our var. 6; Dal-
man had well separated the two in 1826. In uniting, as we have done,
the var. 6 to the typical form, we believe we shall be justified by most
naturalists, when the numerous varieties common in every collection are
examined with a view to this. The combination of characters is the
same in both, and variation im isolated pomts should always be sus-
pected. The reference of such differences to sex is merely speculative,
and will require much observation to confirm.

British Localities and Geological Range.— Distributed throughout
the Silurian districts, from the lower LLANDEILO FLAGS TO UPPER
Luptow rock. ‘The shales of Kirkcudbright, Scotland (J. W. S.) ;

rarely in the Coniston limestone, Westmoreland ; quoted also by Prof.

Sedewick, from Coldwell, ditto (Geological Journal) ; this is a mistake, as

_isalso the quotation in the list of fossils, 7b., vol. 1., p. 20. Upper Silurians

of Denbighshire (J.W.S.). Near St. Clairs and Narberth, in Llandeilo
flags. Marloes Bay, Pembrokeshire (Phillips). Dynevor Park, and nu-
merous localities south and west of Llandeilo; also Rhiw-rhwych and

6 BRITISH FOSSILS.

Cefn Liwydlo, north of Llandovery (J. W.S.) Everywhere in upper
Silurian rocks, Herefordshire and Shropshire (Murchison, “Sil. Syst.’’)
Especially abundant in Dudley limestone and shales. Usk, Monmouth-
shire; in Ludlow and Wenlock rocks (J.W.S.) Horse-shoe Farm, Tort-
worth ; Huntly-hill, Gloucestershire ; Caradoc sandstone ; Woolhope
fieone and upper Silurians of Woolhope, Abberley, and Malvern

districts. (Geol. Surv.) Not yet found in Ireland. aK

Var. (.—Marloes Bay, and St. Ishmael’s, Pembrokeshire (Phillips).
oe Brecknockshire (J. W.S.). Brindgwood Chase, in Ludlow rocks ;
Burrington, in Wenlock shale ; near Ludlow, Aymestry, and Nash Sear, Here-
fordshire (« Sil. Syst.”’) Usk, Monmouthshire, from Wenlock shale to
upper Ludlow rock ; Abberley and Malvern (Phillips).

Foreign Distribution.—In Gottland, upper Silurian, rare (Dalman
and Hisinger.) Ripley, Ohio (Green ;—the localities quoted from
Canada are erroneous, Dr. Bigsby’s specimens being of quite different
species, but one, which is probably the true species, was found by him
at Gaspe, Gulf of St. Lawrence).

EXPLANATION OF PLATE I.

Fig. 1. Perfect specimen, in Mr. Tennant’s cabinet, probably from Dudley.

Fig. 1 a. Front view of head; 16, side view.

Fig. 2. Same, dissected; a, front lobe or forehead; 5, spira or neck lobe; ¢, cheek or
wing; d, margin; e, axis of body ring; f, fulcrum of ditto; g, part of the axis of a tuber-
culated specimen ; h, intermediate ribs of the tail. (These are the indications of separa-
tion between the segments.) The g at the tail margin should be omitted.

Fig. 3. Hypostome from Ledbury.

Fig. 4. Magnified view of surface of eye, the cornea tuberculate between the convex
portions which cover the lenses, At (ua), some small abortive lenses are seen. Ledbury.

Fig. 5. A cast of the interior of the eye, the cornea having been removed, and the
lenses fallen out. Vinnal Hill, Ludlow.

Fig. 6. An eye, with very prominent lenses, which are partly visible, where the cornea
has been broken away. Ledbury.

Fig. 7. A fine young specimen, with rather prolonged tail. Dudley, Cabinet of Mr.
John Gray.

Fig. 8. Specimen, with vastly prolonged head spines. Dudley Museum.

Fig. 9. Head, with produced front (male?) Bodenham, Woolhope.

Fig. 10, Cheeks united across the front, and separated from the rest of the head along
the facial suture. The course of the suture beneath (at @) is rather different from that of
the upper side. Vinnal Hill, Ludlow, a rich locality.

Fig. 11. Tail, with the axis narrow and the point prolonged. Intermediate between
P. caudatus and the var. longicaudatus. Vinnal Hill.

Fig. 12. Tail of ordinary form. From Wenlock limestone of Clincher’s Hill, South
Malvern.

Fig. 13. Tail of var. £, longicaudatus. Craig-y-Garcyd, Usk, in Wenlock shale.

Fig. 14. Head of same variety. Burrington, Ludlow.

Fig. 15. Tubereulated (diseased?) tail, with very narrow border. Rock Farm, May
Hill.

Fig. 16. Accidentally introduced; it belongs to the species next described. Long’s
Quarry, Tortworth.

BRITISH FOSSILS. 7

Other British Species of Phacops, of the Section Dalmannia.

Ce a sp. [fig. 16 in Pl. I.]
P. levis, capite quam in P. cauduto, nisi lobis glabelle tumidioribus ;—caudé triangulart,
Jere equilatera, convexa, apice acuto haud mucronato, axt 13-16 annulato, costis lateralibus

10-12, stmplicibus, vix curvatis, ad marginem equalem angustum abrupte terminatis.

Length of tail 14 inches. There are but imperfect heads in the collections of the Geo-
logical Society and Geological Survey. The characters of the tail distinguish it from
P. caudatus; it has much more numerous ribs, which are but hitle curved, and not dupli-
cate; the margin, too, is equal all round, not expanded or mucronate at the end. Young
specimens have not the full number of ribs, and a few of the upper ones are slightly

divided. The most prominent analogy is with P. Hausmanni, Brongn.; but that is

strongly tuberculate, almost spinous, all over. P. pleuroptyx (Green), is also like, but has
the lateral ribs duplicate. The species of this group so closely resemble each other, that
we dare not givea name. Should it prove new, it might be called P. Weavert.
Localities—Caradoe sandstone of Long’s Quarry, Damory Bridge, and Charfield
Green, Tortworth, Gloucestershire ; (all small); Woodford Green, ditto; (large).

2. P. obtusicaudatus.

P. capite quam in P. caudato, sed latiore ;—caudd brevi, lato, subtriangulari, apice
angulato, obtuso ; axt lato, convexo, 11-12 annulato, obtuso ; costis lateralibus 9, duplicatis,
rectis, ad marginem angustum equalem abrupte terminatis.

_ We merely note this curious species here; it will be figured and described in Prof.
Sedgwick’s work on Westmoreland.
Locality.—Coldwell, in flags above the Coniston limestone, Westmoreland.

3. P. truncato-caudatus, Portlock, Geol. Rep. Tyrone, &c., pl. 2, f. 1-4, and Para-
doxides? Bucephali var., pl. 1, f. 8 (hypostome).

P. granulatus, capite antice truncato, oculis maximis subdepressis ; pleuris obtusis, fulcro
ab axi valde remoto; caude axi 18-annulato, angusto, costis lateralibus 14-16, apice
emarginato.

This interesting species, while in the large eyes and strong head spines, numerous joints
of the tail, and general depressed form, it is nearly allied to the other Dalmannie,—yet
indicates more than any other the close affinity of this section with Phacops, for the facial
suture is only just within the margin, the tail rather rounded than produced, the pleuree
have their furrows strong and curved forwards at their obtuse ends, and they are bent
down at the distant fulcrum, so as to be much better fitted for rolling up than is usual in
Datmannia. For the first half of the thorax they are scarcely at all bent back from the
fulcrum ; the posterior pleurze are more in the usual way. The hypostome is very much
extended at its base, is pointed, and has two pair of oblique furrows.

Localities—Lower Silurian. Tyrone, Ireland. Coniston, Westmoreland. Horderly,
Shropshire. x

Var. 6 affinis. Caude axi latiore—Dalmannia affinis, Salter, in Memoirs of the Geol.
Survey, vol. ii., part 1, pl. 5, f. 5.

It is to be feared there are not sufficient grounds for separating this species, founded only
on caudal shields, A tolerably perfect tail in Mr. D. Sharpe’s collection, and an imperfect
one in the Survey Collection, have the axis considerably wider than in Portlock’s
originals. Specimens, however, in Sir R. I. Murchison’s cabinet, show intermediate
characters.

Localities.—Lower Silurian. Llandowror, Caermarthenshire. Coniston, Westmore-
land.

Phacops is a widely distributed genus or group of trilobites, remarkable for the large
facets of the eyes,—the distinct trilobation of head, thorax, and tail, the furrows separating

8 BRITISH FOSSILS.

the lobes being strong and deep,—and for possessing eleven joints in the thorax, a number
apparently never deviated from. Besides these, in a large part of the genus the convex
form of head and tail, the curvature of the segments of the thorax, and the sharpening of

their anterior margins, eminently fit the animal for rolling up into a compact ball; for this —

purpose it is as completely constructed as Calymene, while it has the advantage over the
latter genus in its large organs of sight. Jt may be considered as the very type of a Tri-
lobite, possessing all the characteristics of the tribe, with a compact and elegant form. And
while the whole group is so bound together by common characters as to render it difficult

to separate it into distinct genera, there is a great variation of form among the numerous ~

species. Quenstedt, and after him Emmerich, united them all, and Professor Burmeister
has not ventured to dismember the genus. Subgenera, however, have been frequently
pointed out, and the groups so formed are very natural. We have—

Ist. Convex species, with the pleure rounded at the end, and sharpened for rolling ; the
glabella inflated, and with but one lobe at the base; the facial suture beneath the margin
of the head in front; the head angles rounded, the tail of few joints.—Portlockia, M°Coy.

2nd. Moderately convex, with the pleure rounded; the glabella not inflated, but with
(8) distinct lateral lobes; facial suture marginal in front; head angles rounded, or
variously produced, tail few (less than 11) jointed, rounded or pointed. — Phacops,
Emmerich.

3rd. Characters as given above.—Dalmannia, Emmerich.

Ath. Flattened; pleure pointed, or even mucronate; glabella and facial suture as in
Dalmannia; head angles long-spinous; tail many-jointed, the margin produced into spines.
—Crypheus, Green; Pleuracanthus, Milne Edw.

Odontochile, Corda, is synonymous with Dalmannia, and his Asteropyge and Metacan-
thus apparently with Crypheus.

The genus is found in all Silurian strata, and existed till the commencement of the
Carboniferous system. The distribution of the various subgenera in Britain is as follows :—

Portlockia is found in all the above strata. P. Stokesii, Milne Edw., and P. sublevis,
M°Coy, Silurian. P. Latreillii, Steininger, P. yranulata and P. levis, Munster, Devens
and lower carboniferous rocks, Devonshire and Cornwall.

Phacops is Silurian. P. Odini, Eichwald, P. Brongniartii, P. Dalmannii, P. Jamesii,
Portlock, Lower Silurian. P. Downingie, Murchison, Upper and Lower Silurian.

Dalmannia, Upper and Lower Silurian. :

Crypheus, Green [C. callitelus, &c., so named before the definition of Milne Edwards’
genus, Pleuracanthus], Devonian. A specimen of C. arachnoides, Goldfuss, found at
Torquay, Devonshire, is in the collection of Mr. D. Sharpe.

J. W. Saurer.
June, 1849. |

gS alae Sg SS ae

ach ARS ei

eg ee ee ey

7 ae
DEGADE. 2,PL,2eee

Weological Surbep of the Untted Kingdon. ULLAENUS —

(Silurian )

ILLA.NUS~ pavist1___-— Sadéer-. : i

BRITISH.FOSSILS.

DecAprE I]. Puars II.
ILLENUS DAVISII.

[Genus ILLAANUS. Datman. (Sub-kingdom Articulata. Class Crustacea. Order
Entomostraca. Family Trilobite.) Head about a quarter of a sphere; eyes smooth,
remote ; facial suture ending on the posterior margin behind the eye, marginal or sub-
marginal in front; hypostome entire, separated from the facial suture by a transverse
rostral shield; thorax segments 9 or 10.]

[Subgenus J//enus. Axis of thorax separated from the pleure by distinct furrows;
fulcrum not close to the axis. |

Diaanosis. TI. capite pygidioque equalibus ; oculis parvis prope sulcos
axales, a margine occipitali diametrum et plus distantibus; thorace seg-
mentis 10, axt pleuris equali; fulero in segmento primo ad axin approxi-
mato, in postremo dimidium pleure vix attingente.

Synonyms. J. Bowmanni [Specimens from Rhiwlas. only], Satter
(1845), in Geol. Journ., vol. i., p. 20; also p. 8. Jllenus crassicauda,
SHARPE (1848), Geol. Journ., vol. iv., p. 149.

Description.—Length 24 to 3 inches. General form oval, very con-
vex ; length to width 17 : 10; the head and tail nearly equal in length ;
the thorax about two-thirds the length of either, and strongly trilobate ;
the axal furrows are carried less than half way up the head, and but a
very little way into the tail: head a quarter of a sphere, and regularly
convex, not peculiarly gibbous behind, where it is divided into three
nearly equal parts by the slightly converging axal furrows; these curve
out again opposite the eye. The eye is of moderate size, gently lunate,
placed much nearer the furrow than the outer edge, and fully its own
length or more from the posterior margin. ‘There is no internal ridge

___ at the place of the neck furrow. Facial suture divergent above the eye,
q and slightly so below it, so as to cut the margin beneath the most pro-
__ minent curve of that organ. Rostral shield shuttle-shaped, covered by

transverse, close, sharp lines, the lower edge a little produced and over-
hanging. Hypostome .....? Thorax of 10 narrow segments, the axis
strongly marked, convex, and subfusiform ; wider than the pleure in
_ the forward segments, in the last only equal to them. The fulcrum is
every near the axis in the first segment, and in the last one is placed less
than half way along the pleure, which are sharpened anteriorly beyond
a 2

2 BRITISH FOSSILS.

this point. The anterior segments are bent down slightly, and also a little
backward at the fulcrum, while the posterior ones are only bent down-
wards. ‘Tail semicircular and moderately convex ; the axis indistinctly
marked out by two deep impressions, which sometimes form short rapidly-
converging furrows ; the upper corners are bent sharply down beyond the
fulcrum, in order to pass freely under the thorax-rings in rolling; the
incurved under portion is concentrically striate as usual, not broad nor —
indented by the termination of the abdominal axis.* General surface
of the head not well known; a few wandering lines appear on one spe-
cimen near the margins of the cheeks; the thorax rings are unorna-
mented: the general aspect is smooth.

Variations.—The axis in some specimens is narrower in proportion to
the pleure (fig. 7).

Affinities. —This species requires close examination to distinguish it
from several others. J. Bowmanni has only nine rings to the very short
thorax. The Jil. crassicauda has a head very gibbous behind, and
longer than the tail; the eyes placed at less than their own length from —
the neck margin, and remotely from the axal furrows; the tail, which
has the axis distinctly marked all round, is scarcely longer than the
thorax, and the latter has its axis broader and flatter than in our spe-
cies; the fulcrum of the pleurz not close in front, and at a full half
behind; the mcurved under portion of the tail is far broader and less
concave, and its lines of growth meet at an angle in the middle; this
last portion is, however, not always visible for the purpose of com-
parison. ‘The whole surface, too, is covered with strong, sharp lines,
which are certainly not conspicuous upon J//. Davisii, though the latter
is not quite smooth. JU. perovalis (Murch ) is a more elongate oblong
species ; the axis of the tail is very narrow, more so than in our nar-
rowest variety, extends one-third down its length, and is circumscribed ;
the incurved portion of the tail is broad. It is not at present justifiable
to connect even this latter with I7/. crassicauda, although it agrees more
nearly with it than with any other species.

History.—Apparently it was not known till Professor Sedgwick and
myself collected it at Bala, in what was then considered a peculiar band
of limestone, and it was too hastily identified with the Ji/. Bowmanni
(Mem. Geol. Surv., vol.ii., part 1, pl. 8, figs. 1, 2, 3), andas such pub-
lished in the list of Welsh fossils given in the 1st volume of the Geol. —
Journ., p. 20: the Rhiwlas locality belongs to the present species. Mr.
D. Sharpe, in noticing the probable occurrence of Ill. crassicauda in
America, states that this fossil is found at Rhiwlas; the present species |
only is intended, and Mr. Sharpe differs with me as to its specific value. :

* This indentation is frequently to be seen in Asaphus; it is strong in Jllenus

crassicauda, Dalm.

’

BRITISH FOSSILS. 3

British Localities and Geological Range—Luanveito Fags only.—
- Abundant in the Bala limestone at Rhiwlas, at the foot of the lake, and
also at other localities in the immediate neighbourhood both north and
east of the lake (Coin. or Grou. Survey). It appears, however, to
be but local, and its place is taken through many other parts of North
Wales, and all through South Wales, by the Ill. Bowmanni. It pro-
bably occurs in the lower Silurian limestone of Wrae, near Broughton,
Peebleshire ; some fragments were found there by Mr. James Nicol
(Geol. Journ., vol. iv., p. 206), which are with doubt referred to this
species, as also is another portion of thorax found in the limestone of the
-Stincher river, Ayrshire, by Mr. Carrick Moore (75., vol. v., p. 18).

EXPLANATION OF PLATE II.

Fig. 1. Nearly perfect specimen. Rhiwlas, Bala; in which locality all, except figs. 6,
7, were found. Fig. 1*, side view of ditto.

Figs. 2, 2*. Front and side views of a rolled-up specimen; the want of gibbosity in the
head is shown in the side view.

Fig. 3. Dissected figure. a, central lobe; 6 6, wings, upper side; they extend further
inward on the under side; ec, axis of a middle thorax segment; dd, fulcra; ee, fulera
of tail.

Fig. 4. A separate tail, showing the incurved under portion, d, where the upper crust is
broken off.

Fig. 5. Rostral shield, often found separate.

Figs. 6, 7. Tails of young specimens, showing the further extension of the furrows at
that age. Llechwedd ddu, Bala.

Fig. 8. Variety with narrow axis. The tail has been compressed from below, and
appears too small. Rhiwlas. ‘

British species of Léilenus proper.
* With 9 body-rings.
1. I, Bowmanm, Salter, Mem. Geol. Survey (June, 1848), vol. ii., part 1, pl. 8, f. 1-3;
I. centrotus, Portlock (1843), Geol. Rep., pl. 10, f. 8-6, and probably f. 9.
Lf. capite magno, angulis posterioribus obtusis ; oculis remotis, ad marginem occipitalem
approximatis ; thorace caudda breviore.
Locality.—Llandeilo flags, North and South Wales ; Kildare, Ireland.

} ** ‘With 10 body rings.
2. I. Davisii, as defined in our preceding description.

3. I. Portlockii, Salter; I. crassicauda, Portlock (1843), Geol. Rep. Tyrone, &c., pl. 10,
f. 7, 8 | Thaleops ovatus, Conrad ; Hall, Paleont. New York (1848), pl. 67, f. 6b.?

1. capite magno, cauda parva, subtrigona ; vculis remotis [prominulis?] ; thorace seg-
mentis 10, axt lato, pleuris abrupte deflexis et reflexis ad fulcrum, quod ad dimidium pleure
uniusquisque positum est ; caudd depressa, subtriangulari, angulis extremis laté truncatis.

That this neat species is not JL. crassicauda is very clear; the shape of the tail, and the
abrupt backward bend of the pleura, almost at right angles, distinguish it easily; the
_ fulcrum is as far outward in the first segment as the last, an unusual character. We have
not seen specimens of J. ovatus (Conrad); Hall’s figure of that species (loc. cit., pl. 67,
f. 6b) much resembles ours in the tail; but if his two specimens be correctly drawn, he

4 BRITISH FOSSILS.

must have figured two species under the name. We cannot therefore identify the Irish
fossil with his, especially as the decided bend in the pleure is not given in his figure;
and we dedicate the species to Col. Portlock, who has so well elucidated the trilobites of
Ireland. Our description is drawn from his specimen,

Locality.—Lower Silurian rocks of Tyrone, Ireland.

4. I, perovalis, Murchison, Sil. Syst. (1839) t. 23, f. 7.

I. capite gibboso, oculis remotis ; thorace quam cauda longiore, segmentis 10, aat angusto ;—

pleuris paulo reflexis ad fulcrum, quod pleurarum feré omnium ad tertium positum est, caude
axt angustissimo, circumscripto.

In the young specimen figured the eyes are not seen, but they must be nearly as dis-

tant from the axal furrow as the width of the central lobe; the axis of the thorax is much
narrower than the pleure—this is maintained in the adult; the fulcrum at about one-third
in the first segment, in the next a little farther out, and from thence at an equal distance
in all the segments. Tail in youth more than a semi-circle, shorter than the thorax, with
the axis very narrow, circumscribed, and reaching about half-way down; in the older
state it forms about a semi-circle, is flattened, and the axis does not reach so far. The
end of the axis does not indent the broadish incurved margin of the inferior side; it does
so in J, crassicauda, which has a shorter and subtruncate convex tail, a much broader
axis to the thorax, and the eyes not nearly so remote. We have not specimens perfect

enough to characterize J. perovalis fully, but enough to show that it ought not at present —

to be connected with the Swedish species.

Locality.—Liandeilo flags of the Corndon Mountain, Shropshire.

5. I. ocularis,—n. sp.

I. capite semicirculari, utruque acutangulo, lobo centrali angusto; oculis magnis, approxt-
matis, a cervice vix dimidium diametri remotis: thoracis axi pleuris equali, his ad fulcrum
deflexis et paulum reflexis ; pygidio 2

A species so remarkable among the trilobed division of Zllenus, for the size of the eye,
that we have ventured to name it—we cannot recognize it among published species.

Locality. Llandeilo fiags, county Kildare, Ireland.

6. I. Murchisoni, Salter. J. Rosenbergii, ib.. Mem. Geol. Surv., vol. ii., pt. 1, pl. 5, f. 6-8.

I. captte cauddque magnis, thorace brevi, anterius contracto ; capite utrdque acutangulo,
oculis ad sulcos approximatis, diametrum suum a cervice remotis ; thorace axi latissimo dis-~
tincto, pleuris antertoribus brevissimis.

A species connecting the true Z/lent with Bumastus, having a very wide axis and very

narrow front pleure. The axis, however, is really distinct, and the fulerum not close to.

it. There is reason to believe that the L. Rosenbergii, to which these specimens were
referred before, is a very large specimen of J. crassicuuda: as Pander and Burmeister
have previously stated. This fine ///@nus, from near the classic town of Llandeilo, we
dedicate to Sir R. I. Murchison. ’

Locality.—Llandeilo flags of Llandeilo, South Wales.

Notwithstanding its great similarity in external characters to ileus, Illenus is essen-
tially distinguished by the possession of a rostral shield, a portion so designated by Bur-
meister, and peculiar to Jllenus and Calymene. This shield appears to be a plate inserted
between the two cheek-pieces, and separates the hypostome, or labrum, from the facial
suture. In Asaphus the cheek-pieces are united across, or in some divided merely by a
vertical suture. JU. centrotus (Dalman) has long head-spines, and in this differs from most
species of the genus, though some others are angular at the corners. Pander, and after
him Sars, described the hypostome; it is simply oval, and by no means notched, as in
Asaphus.

The genus commenced in the Llandeilo flags, and continued to the end of the Silurian
system. We think there is not good evidence of its longer duration, though Munster cites
one or two species from Devonian rocks in Germany.

June, 1849. J. W. SALTER.

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Seological Surven of the United Kmgdom. ILLANUS.
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——

ILLANUS (BUMASTUS) BarRIiENSIS ——.Yurchison

Heological Surbep of the United Kingdom, ILLAENUS

(Silurian)

BRITISH: FOSSILS,

DecapbE II. Puares III. ann [V.

os

ILLZNUS BARRIENSIS,

[Genus ILLAINUS. Datman. (Sub-kingdom Articulata. Class Crustacea. Order
Entomostraca. Family Trilobite.) Head about a quarter of a sphere; eyes smooth,
remote; facial suture ending on the posterior margin behind the eye, marginal or sub-

marginal in front; hypostome entire, separated from the facial suture by a transverse
rostral shield; thorax rings 9 or 10.]

[Sub-genus Bumastus. Thorax with 10 rings, not trilobate; the axis very broad,
reaching to the fulcrum. ]

Diacnosis. I. (Bumastus) ovali-oblongus, valde convexus, crusté crassa ;
capitis sulcis axalibus remotis; oculo magno prominente, vix dimidium
longitudinis sue a cervice remoto, palpebra* valde convexd ; thorace arti-
culis 10, haud trilobato.

Synonyms. ‘ A new species of Trilobite,” F. Juxzs (1829), in Ann.
Mag. Nat. Hist., vol. ii, p. 41, figs. 8, 9, 10; ‘probably Isotelus,” J.
D. C. Sowrrsy, 7b., p.45; Srruiman, Amer. Journ. of Science (1832),
vol. xxili., 1, p. 203. Bumastus Barriensis, Murcuison (1839), Sil. Syst.,
pil. VIL. bis., fig. 3; ib. XIV., f.'7; EmmeEricnu (1839), Dissert. 38. Nileus ?
(Bumastus) Barriensis, Mitne Epwarps (1840), Crust., vol. iii., p. 295.
Ill. (Bumastus) Barriensis, Burmeister (1842), Org. Tril., 120; Ray
edition (1846), 104. Bu. Barriensis, Hatt (1843), Geol. Report, New
York, No. 10, f.4; No. 19, f. 2. [ileus glomerinus, DALMAN, Arsberiatt.
(1828), p. 186; Histverr (1837), Leth. Suec. 16 ?]

Description.—Oblong-oval and very convex; the three divisions,
head, thorax, and abdomen, nearly equal. Head a quarter of a sphere,
‘more pointed in front in the young specimen than in the adult, in which
it becomes obtuse. The surface of the head is even, and but slightly
marked by short converging distant axal furrows into glabella and
cheeks. Terminating these short furrows, and immediately above the
prominent upper eyelid (palpebra) is an oval space, sometimes flat of
depressed, and sometimes a little convex, where the crust is thickened
Interiorly, and on which the puncta that occur so commonly on the
other portions of the crust are absent in some specimens,—its nature

* Dalman uses the term “ Jobus palpebralis” for the covering plate or eyelid: its varia-
tions are often characteristic.

[11. ili. & iv. ] 2D

2 BRITISH FOSSILS.

we do not know. Eye strongly lunate, long, narrow, smooth, and sup-
ported by a very strong fold of the cheek, which forms a sort of lower
eyelid, and is most developed in age. Cornea apparently thick. The
facial suture in front of the eye runs S-shaped outwards and upwards,
turns a little beneath the margin, and then runs straight across above
the rostral shield; it bends out sharply beneath the eye, and cuts the
margin beneath the most prominent curve of that organ. Rostral shield
a long transverse piece, deeply striate, and overhanging with a sort of
pouting lip the attachment of the hypostome. ‘This last piece is yet
undiscovered.* Cheeks with rounded angles posteriorly, and curving
over the lower side of the head; they are separated by the wide
rostral shield.

Thorax of 10 segments arched back, especially the forward ones,
and having the three lobes just indicated by a very slight furrow ere
the fulcrum is placed, the subfusiform axis occupying more than two-
thirds the entire width. The fulcrum is far outwards, and is formed
by a short forward bend of each pleura, which then continues in the
general direction, is sharpened anteriorly for rolling, and curves forward
at its blunt end ; the foremost pleure are rapidly shortened, the whole
of the cheeks projecting beyond them (plate 3, f. 1*a).

Tail in the young about three-fourths of a hemisphere ; in the adult
more than half. The upper corners are truncated and turned down,
but there are no indications of the axal lobe. Incurved portion of the
tail not broad, but thick, deeply concave, and marked concentrically
on both surfaces by elevated lines of dots (pl. 4, f 10, 10a). The
whole surface of the animal is more or less punctate, and marked with
wavy imbricate lines; they appear to vary very much in number and
position, abound near the edges of the head, but less so on its most
convex portion; run across the thorax parallel to the course of the
rings, and on the tail are most abundant on its forward margin. On
all the articulating surfaces the lines are doubly close, but the puncta
absent. On the somewhat depressed space immediately over the fulcral
points in the head and thorax-rings, both lines and puncta vanish.
These latter, which most probably indicate the bases of short pile, are
often wide and deep (pl. 4, f. 3), and are present on the posterior
surface of the tail, where the lines are absent. ‘The inferior eyelid |
(pl. 3, f. 1*0), if so it may be called, is deeply punctate in our specimen,
but without any of the wavy lines.

Variations.—Though numerous specimens are extant, there are so
few perfect ones, that we are not able to detect any considerable variety
in the proportions. Certain Dudley specimens appear more elongate.

* Mr. John Gray of Dudley possesses an entire transverse labrum, with two tubercles,
which very likely belongs to it.

BRITISH FOSSILS. 3

Affinities.—But one is published which belongs to this section of the
genus besides our own, the Jdlenus trentonensis of Emmons (Geol.
New York, 2nd district), and through the kindness of Dr. Bigsby, the
well-known explorer of the Canadian frontier, we have seen a specimen
as large as our largest individuals of Z. Barriensis, from Little Mani-
- toulin Island, on Lake Huron. It differs, at a glance, from ours, in
the angularity of the posterior angle of the head, and its strongly
converging and lengthened axal furrows. Whether Dalman’s Nileus
glomerinus, described in 1828, be this species, as Burmeister thinks it
may, we have no means of deciding at present. |

_ History —The earliest notice of the British fossil was given under
the name of “ A new Trilobite from Dudley,” by Mr. Frederic Jukes,
who communicated drawings and casts, and a note by Mr. J. de C.
- Sowerby, to Loudon’s “ Magazine of Natural History ;” the specimens
were obtained from near Barr Beacon, Staffordshire. Mr. Jukes also
communicated casts soon after to Silliman, for his ‘‘ American Journal,”
and it is there stated that Mr. Sowerby had referred it to a genus
found at Trenton Falls, the Zsotedus of Dekay. Professor Green, how-
ever, would not admit the identity of the two genera, and denied
the existence of the English type in America. This was quite true at
the time, but it is singular enough that the Trenton limestone should
- afford afterwards another and almost identical species. Sir R. I. Mur-
chison, as is well known, founded his genus Bumastus on this Wenlock
fossil. Milne Edwards did not adopt it, and considered it closely re-
lated to Nileus ; while, however, he referred the other species of Ldlenus
to Dekay’s genus Jsotelus. Burmeister, in 1842, placed it in its pre-
sent position as a section of L//enus ; while the species of ileus, which
Dalman distinguished from all trilobites (not knowing our species) by
their want of trilobation, have fallen into their true position among the
large group of Asaphus. ©

British Localities and Geological Range.—Si1Lur1awn Rocks ; Wool-
hope limestone to Wenlock limestone. Wenlock formations of Hay
Head, near Barr, Staffordshire (Sir R. I. Murchison). Dudley, Staf-
fordshire. Haven, near Aymestry, Herefordshire (Rev. T. T. Lewis).
Woolhope limestone of Littlehope, Woolhope; and also of Nash Scar,
Presteign, Herefordshire. Wenlock limestone of Ledbury, Malvern
(Coll. Geol. Survey.)

Foreign Distribution..—Niagara group of New York (Hall). A
species very like it was found near Hohenholm, by Eichwald (Urwelt,
Russland, Heft, 2, 59), but it is not quoted from Norway or Sweden.

4 BRITISH FOSSILS.

EXPLANATION OF PLATE III.

Fig. 1. Old individual from Barr, in the possession of Miss Jukes, of Birmingham.

Fig. 1*. Side view of the same, showing the shortened foremost pleurz (a), and the
inferior eyelid (0).

Fig. 2. Side view from a fine coiled specimen in the cabinet of John Gray, Esq.,
Dudley.

Figs. 3, 3*. Two views of a young one; in the cabinet of Augustus Lewis, Esq.

Puate IV.

Fig. 1. The dissected figure. a, head; & b, cheeks; c, thorax segments ; d, tail.

Fig. 2. Portion of surface above the eye, showing the wavy lines and puncta.

Fig. 3. Ditto, with puncta larger than usual.

Fig. 4, Magnified pleurz, with lines and puncta.

Fig. 5. Part of tail, the puncta only present over the hinder portion of it.

Fig. 6. Pleura magnified, showing the fulcrum a, the backward bend at 6, the sharpened
forward edge c.

Fig. 7. Large head from Littlehope.

Fig. 7*. The same, lower side. a, rostral shield; b, rostral suture (Burmeister).

Fig. 8. Shows the thickened portion of shell just above the eyelid at a; impression of it
on the stone beneath at b. (In this specimen it is destitute of puncta.)

Fig. 9. Side view of part of tail; at a, the fulcral point; 5, the articulating surface,
with lines, but not puncta.

Fig. 10. Incurved portion of tail; the inward surface with elevated granulate lines.

Fig. 11. A ditto, magnified.

The specimens figured in this plate are in the Geological Survey Collection.

The section Bumastus is related to the more typical species of Jllenus, just as ileus,
of Dalman, is to his Asaphus palpebrosus. The distinct trilobation has vanished, and the
axis is so wide as to reach the fulcral point, and be nearly coincident with it. There is
a slight backward bend of each pleura just before the fulcrum, which serves to steady the
articulation of the piece behind by overhanging it a little, while this piece, in turn, over-
hangs the preceding at the fulcrum, precisely as in the articulation of the abdomen of the
lobster and cray-fish. Beyond the fuleral point the pleura is always more or less sharp-
ened, to pass under the preceding joint in the act of bending; and, as in this operation,
the back is lengthened, and the soft parts of the axis would be exposed by the separation
of the segments, a convex articular portion is added on the forward edge of each segment,

which fills the gap, and retires beneath the preceding joint, when the animal is extended.

This is the structure of all trilobites which have been observed to bend or roll, and it is
similar to that met with in recent crustacea.

The subgenus is known in the Lower Silurian rocks of America, and the Upper Silurian
of Britain.

J. W. Savrer.

June, 1849.

DECADE 2.PL.5.

=

Geological Surden of the Muited Kingdom. ASAPHUS

(Silurian)

3b

; ASAPHUS tTyrRANNUS __ Wurchisow.

C.R.Bone del. ? ; E. Forbes direx:

pRIPTIS HF OS S148.

DecapveE II. Puate V.

ASAPHUS TYRANNUS.

[Genus ASAPHUS. Bronentart. (Sub-kingdom Articulata. Class Crustacea. Order
Entomostraca, Family Trilobite.) Eyes large, smooth. Facial suture marginal or |
supramarginal in front, and ending on the posterior margin. No rostral shield. Hypostome
strongly bilobed. Body rings 8. ]

[Subgenus Basilicus, Salter. Facial suture marginal in front; head but slightly lobed ;
pleurze furrowed transversely ; tail large, with axal and lateral furrows.

Diaenosis.—A. (Basilicus) ovalis; capite semicirculari, angulis in
spinas breves productis ; cauda. parabolica, late marginata, regulariter con-
vexa, apice retundato nec acuto; axi distincto, sublineari, angusto, multi-
costato, apice abrupto ; lateribus multicostatis.

Synonyms. Asaphus Tyrannus, Murcuison, Silurian Syst. (1837),
pi. xxiv. and pl. xxv., fil. Ogygia Tyrannus, Emmenicu, Dissert. (1839),

29. Asaphus Tyrannus, Mitnr Epywarps, Crust. (1840), 3, 310. EmMe-
RicH, Leonhard and Bronn’s Neues Jahrbuch 1845 (translated in ‘ Scientific
‘Memoirs,’ vol. iv. (1845), 273). [mot of Burmetsrer, Organ. Trilob.
(1843), t. 5, f. 4. Ray edition (1846), 108.]

A remarkably perfect specimen in the cabinet of W. Day, Esq., of
Hadlow near Uckfield, and specimens in the Geol. Survey collections
displaying the parts of the mouth, enable us to present a complete
description of this famous, but apparently local trilobite.

Description.—Length 11 inches ; breadth 63 inches. General form
nearly a true oval, moderately convex ; the head semicircular, the tail
Jonger and parabolic. Head smooth, with a slight concavity marking
off the margin, produced at the angles into short spines which reach the
third thoracic segment. Glabella clavate, defined in front only ; the
forehead lobe large, protuberant, and nearly round: beneath it, and at
the level of the front of the eye, is the uppermost of three obscure
oblique furrows. There is at the base of the glabella a tubercle, and
beneath it an impression marking the place of the neck furrow. Eyes
rather large, much arched, placed behind the middle of the head, and
close to the glabella ; the base of the eyelid is constricted, the lentiferous
_ surface is broad and smooth, and beneath the cornea there are very
[11 v. | 2-5

2 BRITISH FOSSILS.

numerous lenses,* not quite closely set. Facial suture ending on the
posterior margin, at the inner third of the width of the cheek, and in
front of the eye turned outwards in a sigmoid curve ; it cuts the front
margin beyond the parallel of the eye, and continues exactly along the
edge of the shield. :

The hypostome is semicircular at its base, which is moderately broad ;
it has a squarish tumid centre surrounded by a strong furrow, and is ~
deeply divided at the apex into two ovate-lanceolate forks, between
which the shelly plate turns strongly inwards: there is an oval circum-
scribed tubercle at the origin of each, most distinct on the inner
surface.

Thorax of eight moderately arched "ee the axis not strongly
marked and as broad as the pleure; these latter are furrowed for
three-fourths of their length, and are curved down, but scarcely bent
backward, at the obscure fulcrum, which in the hinder rings is placed
at about one-third away from the axis, but much nearer to it in the
forward rings; the anterior edge of each pleura is sharpened, and its
termination square. :

Tail parabolic, its width at the broader end one-fourth greater than
the length (it appears nearly equal), regularly convex, not sunk in the
middle ; axis flattened forwards and prominent behind, terminating
abruptly at four-fifths the length of the tail, and ribbed throughout by
about 15 furrows. The sides are furrowed for about half their width
by 12 or 13 oblique parallel sulci, which end abruptly at the edge of
the broad concave margin; the uppermost furrow is much stronger
than the rest. The incurved lower surface of the tail occupies rather
more than the breadth of the smooth upper border, and folds round the
end of the axis which indents it. The fine lines on this incurved border
are not truly concentric with the edge, but appear to branch from an
imaginary line along the middle or most concave part. The space left
between the upper and lower borders is shallow. On the upper crust
of the tail the wavy lines are interrupted and inosculate; they arch
over the axis with the convexity of the curve forwards: on the lateral
lobes the curve is reversed. The same arrangement is seen on the
thorax rings,—at the ends of the pleure they turn upwards, and fig. 8
shows the longitudinal disposition of these lines on their under sides.
Qn the head similar lines occur, but we have not specimens to show it
well; the hypostome has them obliquely on the forks (fig. 4).

* On a specimen Jent by Mr. Day, which presents only the lower half of the eye,
the number and arrangement is such, that judging from analogy with A. Powztstt, the eye
of which is very much like this, there must have been 6000 lenses, or probably more.

+ Burmeister has figured a good example of this arrangement of the sculptural lines on —
the tail of an Asaphus in his “ Zeitung fur Zonlogie,” &c., 1 Band, 1848, t. 1, f. 19.

BRITISH FOSSILS. 3

_ Variations. —Some individuals (perhaps females) are much more
convex than others; in some the margin is abruptly concave; our
figured specimen is depressed. The number of lateral ribs to the tail
varies considerably, they do not seem to become more numerous by
age. The forks of the hypostome are long or short. The ornamental
lines which are so conspicuous in the external cast (Pl. 24, Sil. Syst.)
exist, though less deeply sculptured, in all; the imternal cast, which is
more commonly found than perfect specimens, does not show them
distinctly.

Affinities.—The specimen figured in Burmeister’s work appears by
his description to have been from a “boulder of red limestone,” and
hence it is very probably a worn specimen of A. heros (Dalman), from
the red limestone of Kinnekiille, Gothland. It is unfortunate that the
author should have transferred the sculpture of A. tyrannus to this
figure, for the axis is constricted in the middle and depressed, and the
lateral ribs long; it is in fact a pretty good figure of A. heros, except in
the rounded tail; in Swedish specimens the tail is pointed and the axis
percurrent. ‘There is also a species in the lowest Silurian limestone of
New York so like ours, that we do not know how it is distinguished ;
there are, however, but seven or eight distinct ribs on the axis, and
those on the sides are said to be duplicate; we refer to A. marginalis
. (Hall), described in the Paleontol. New York. This is the more inter-
esting, as the Asaphi of North America belong generally to the group
Isotelus.* ‘The species which most nearly resembles A. tyrannus, and
which I referred to it in Prof. Sedgwick’s papers in the “ Geological
Journal,” is the A. Powisti, very common in the slates of North Wales.
The specimen of this latter species figured in the “Sil. Syst.” is much
compressed, for the species is really more convex than that here
described, with deeper furrows on the pleurze, which are arched forward
at their ends; and the tail axis is wide above, rapidly contracting in
width and becoming quite indistinct, its end only prominent; the surface
seems smooth; the sides of the tail have a very strong uppermost
furrow ; the remaining furrows are faint. Fine specimens of A. Powisi?,
in the collections of the Geol. Survey and of Mr. Sharpe, show very
numerous lenses (about 7000) on each eye.

istory.—lt appears not to have attracted the notice of Llhwyd,
although it is quite as common at Llandeilo as the Ogygia Buchit, of

which he figured specimens; nor does it seem to have been noticed

by any writer on trilobites previously to the publication of Sir R. I.
Murchison’s work. Emmerich, in his Dissertation, showed how close he
considered its affinities to be with Ogygia, by transferring it to that

* The young animals of even this group, according to Hall's figure, are trilobed and
ribbed in the tail ; but that can only be in a very young state.

4 BRITISH FOSSILS.

genus. In 1845, however, he restored it to Asaphus, though he evi-
dently had not observed the characteristic labrum. Burmeister appears
not to have been acquainted with the species, since in both editions he
confounds it with what we believe to be a specimen of A. heros, and even
suggests, in his Appendix, that Murchison’s smaller figure might prove
to be A. extenuatus. He notes that it appears anomalous for Asaphus
to have such distinct ribs on the tail; and indeed this peculiarity is one
of the indications of its affinity to Ogygia, which we think confirmed by
the course of the facial suture.

Localities and Geological Position in Britain. —LuANDEILO FLacs.—
Limestone of Wrae, Peebleshire? (Geol. Society’s Coll.). Coniston
limestone, Westmoreland? Craig-y-Glyn, Berwyn Mountains, in Bala
limestone (Sedgwick) ; Meadow Town; Shelve, &c., in the Longmynd,
Shropshire ; Carneddau Hill, Builth, Radnorshire [J. W.8.]; Llandeilo,
and many neighbouring localities in Caermarthenshire; Llampeter
Felfry, Pembrokeshire [Murchison]; Narberth ; Mydrim ; Sholeshook ;
Lann Mill, Pembrokeshire (Phillips). It is remarkable that it does not
occur in Ireland.

Foreign Distribution.—It is quoted by Sir R. I. Murchison from
Northern Europe [Quart. Geol. Journal], but with the understanding
that A. heros, Dalm., was intended. A. marginalis, Hall [| Paleont.
New York, pl. 4, zs, f. 15], may be the same as our species.

EXPLANATION OF PLATE V.

Fig. 1. Perfect specimen. Llandeilo. (Collection of W. Day, Esq.)

Fig. 2. Outline of central portion of head, showing the constricted eyelids. Lann Mill.

Fig. 3. Portion of head, with the base of the eye, a. Llandeilo (Mr. Day’s Collection).

Fig. 3*, Magnified portion of a cast from the same, which would represent the surface
of the eye when the smooth cornea is removed.

Fig. 4. Perfect hypostome, with the upper processes (aa). Lann Mill.

Fig. 5. Variety of the hypostome, with shorter forks. Golden Grove.

Fig. 6. Punctate exterior surface of part of hypostome; the lineated surface is shown
in fig. 4.

Fig. 7, Upper surface of a thorax joint. St. Clears.

Fig. 8. Under surface of ditto, showing the extent of the incurved portion 4, 5.

Fig. 9. Part of thorax of a large individual, with deep sculpture. Golden Grove,
Llandeilo.

Fig. 10. Tail of young individual. Llandeilo.

Fig. 11. Incurved part, under side of the tail, bounded by the lines a,a, and deeply
indented by the axis. Clog-y-frain. (Sir R. I. Murchison’s Cabinet.)

June, 1849. J. W. SALTER,

SN Ea ea >

L

Geologteal Surbep of the Nnited Kingdom.

a eee ae

nese

eeoetner sane:

—

ue

ANN)
ly yy

OGY GLAD RUCHT = Drenmgv7ar7.

Riese: FOSS EL S.

DecavE II. Puarte VI.

a

OGYGIA BUCHII.

[Genus OGYGIA. Bronenrarr. (Sub-kingdom Articulata. Class Crustacea. Order
Entomostraca. Family Trilobite.) Eyes large, smooth; facial suture cutting the pos-
terior margin; no rostral shield or vertical suture; hypostome entire; body rings 8;
tail large. ]

Diacnosis. O. ovalis, glabella angusta utrinque quinquesulcata ; oculis
ad medium capitis; sutura facialt ad frontem marginali; spinis posticis
brevibus ; hypostomate obtuse acuminato ; thoracis axt bis pleur& angustiore ;
caude axi longo abrupto; sulcis lateralibus 12 duplicatis, prope marginem
angulatim deflexis.

Synonyms. Lunwyp (1698), Philosoph. Transact., vol. xx., 279, tab.
addit., f.15. Buglossa curta strigosa, ib., Ichnograph. Brit. (1690), Epist. 1,

_ t. 22, f. 2, Trilobite from Llanelly, Parkinson, Organ. Rem. (1811),

v. iii., t. 17, f. 13. Asaphus De Buchii, BronentARrt, Crust. Foss. (1822),
t. 2, f. 2. Trilob. De Buchii, ScHitotuEim, Nachtr. (1823), ii. 34
(excl. the locality, ‘“ Norway.”) Asaph, Buchii, Dalm. Palead. (1826), 68.
J. D. C. SowrErsy, in Loudon’s Mag. Nat. Hist., 1829, vol. ii., f. 27.
Buckianp (1836), Bridgwater Treatise, t. 46, f. 7. Murcutson (18387),
Sil. Syst., t. 25, f. 2. QuenstEDT, Wiegm. Archiv. (1837), vol. iii., 1,346.
Emmenricu, Dissert. (1839), 28. Mitne Epwarps, Crust. (1840), 3, 309.
Burmeister, Org. Trilob. (18438), t. 1, f. 2, [facial suture wrongly figured. |
Ray edition (1846), p. 59.. Corpa, Bohm. Tril. (1847), t. 4, f. 39 [bad. |

—— Junior. Trinucleus? asaphoides, Murcuison, Sil. Syst., t. 23, f. 6.
Mitne Epwarps, Crust., v. ili., 333.

Description.—Length occasionally near seven inches, generally three
or four; proportion of length to breadth from 6:5 to 6: 4, a consi-
derable variation. General form a broad depressed oval, the head

nearly semicircular and as long as the thorax, the tail semi-elliptical

and longer than either; glabella at its base occupying one-fourth or less
of the width of the head, broader and more convex above, and a little

_ pointed in front ; it extends nearly to the front margin, and is marked,
a little within each side, by a longitudinal depression, which is curved

with the convex side inwards. Along this hollow lie five pits, which
represent the glabella furrows; the basal one is the neck furrow, that
fur. vi. ] 2

2 BRITISH FOSSILS.

above is placed near the centre of the glabella, the other three re-
cede more, the uppermost coming just above the eye. -Eyelid large,
semicircular, and not touching the glabella. The facial suture above
the eye is curved outwards a little to reach the margin, along which it
runs for some distance ; beneath the eye it curves largely outwards,
and cuts the posterior edge just withm the border. The latter is wide
and striate, more or less concave, and marked off by a distinct marginal
furrow. Eye placed halfway up the head, smooth, the lentiferous sur-
face broad, its minute structure is not yet known. Head angles not
produced below the fourth body segment. Hypostome broad above,
narrowing below, where it is suddenly and obtusely pointed; the
centre is gently raised, and a furrow runs down each side; there are
two transverse furrows near the apex, with compressed tubercles between
them. ‘Thorax with the axis gently convex, variable in proportion, but
seldom more than half the width of the pleure. These are flattened,
furrowed along the upper margin as far as the fulcrum, at which there is
an obtuse bend (fig. 2, c, a the furrow diverges from the margin
here, and does not quite reach the recurved and pointed extremity ; it
becomes widest immediately beneath the fulcrum, and from the lower
margin of the pleure at this pot a narrow ridge runs obliquely up-
wards, and meets it. Tail varying from little more than a semicircle
to a half-ellipse, very gently convex; the axis gently tapering, ribbed
by about 13 or 14 furrows, which have a downward bend in the middle ;
its obtuse tip projecting. Lateral furrows at nearly right angles to the
axis, angularly bent downwards at the place of the fulerum,* interlined
all the way by fainter furrows, and leaving but a narrow flat margin.
Inecurved under portion of the tail narrow, closely striate, not indented
by the axis; the upper side has a striate band of the same width, which |
is indented by every rib of the tail. The inferior striated band is con-
tinued (of the same width) along the ends of the pleure, and the striz
run in the same direction, while, on the upper surface, they are trans-
verse, and reach further inwards. Numerous fine striz, arched upwards,
cover the axis. ‘The cheeks appear to be nearly smooth, but the gla-
bella is covered by fine, short, broken, almost microscopic lines. ‘The
hypostome is strongly and concentrically striate.

Variations.—It varies in convexity, proportionate length, and in the
width of the axis; this latter is sometimes, though very rarely, more
than hali the breadth of the pleuree—generally half, frequently less than
half. A pair of tubercles on each segment of the axis is present ; they
are distinct and strong in some specimens (fig. 6), and faint in others.

* The tail, consisting of anchylosed segments, preserves traces of nearly all the cha-

racters of the thorax; the strong furrows are analogous to the furrows of the pleure, the
fainter lines between then to the joints.

BRITISH FOSSILS. 5

— Affinities —From O. Guettardi it is known by its less elongate and
more oval shape, and greater width of pleuree in proportion to the axis; 1
_ O. Guettardi they are but once and a-half the width. The axis of the
tail is longer, and has 18 instead of 9 ribs, and is abrupt, not attenuated
at the tip ;—in O. Guettardi it extends but three-quarters the length.
It has, also, duplicate, bent, and more numerous side furrows ; the other
has but eight or nine straight simple ones; the hypostome also is sub-
conical, not dilated laterally. O. dilatata, Brunnich (not of Portlock), :
which seems to have been frequently held as a variety of O. Buchii, has
the glabella short, with its lobes crowded down towards the lower part,
and the eyes remote. The facial suture behind the eyes appears much
less arched in Sars’ figure. He also describes the tail as with 10 mbs,
separated by dread furrows. The labrum of O. dilatata, according to
Sars’ figure, is but slightly different from that of the British species ;
but an important difference resides in the facial suture, which, in O.
dilatata, is within the front margin on the upper side, but in O. Buechiz
is along the edge itself, as in Asaphus Tyrannus.

History.—The earliest mention we can find of Trilobites is concern-
ing this species, and is that which all writers on these fossils have quoted.
Mr. Edward Lihwyd, in a letter to Dr. Martin Lister, of the Royal
Society (1698) writes “ concerning several regularly figured stones lately
found by him.” ‘“ The 15th,” he says, “‘ we found near the Lhan
Deilo*, in Caermardhinshire, in great plenty, it must, doubtless, be re-
ferred to the sceleton of some flat fish; but, a few lines after, “ Not
that these, or any other marine terrestrial bodies were really parts of
exuvie of animals, but they bear the same relation to them as fossi
shells to marine ones,” &e. This latter opinion he takes care to main-
tain in his “ Lithophylacii Brittanici Ichnographia ” (1699), where he
again says, the specimen represents only the skeleton of a sole fish, and
wants the tail, and he marvels that the “ Piscis Icon” should be raised
above the surface of the stone, “ ac si verus piscis esset.” It 1s curious
that Brongniart should have placed this species in his heterogenous
group Asaphus, at the very time he was founding Ogygia, as i ap-
pears to have recognized the latter genus more by its marked habit
than by any positive characters. He probably meant to unite A. dilatatus
with A. Buchit. Dalman distinguished them, but with doubt, in 1826,
and gave a figure of the Norwegian fossil from a plaster cast ; and had
not Sars, in 1835, given a complete description, and a good figure of

* Fig. 9, of the same communication, is often quoted as belonging to 7rinucleus. We
have no doubt it is 7. Caractact, as that is the common species there (7. fimbriatus is
_ found at Builth) besides, the distinct dots in the fringe identify it with the former species.
Fig. 8 appears never to have been quoted, yet it is a tolerable representation of Cybe/e

verrucosa, Dalman, and it has been figured again without a name by Brongniart, plate 4,
f£ 11, from the same locality, where it abounds, and is the only species of the genus there.

4 BRITISH FOSSILS.

the head, the identity might still have been maintained. The hypos-
tome of this species was first represented in Sir R. I. Murchison’s figures.
We have ascertained, by personal inspection, that the Trinucleus Asa-
phoides of his work is the young of O. Buchit. Quenstedt, 1837, unfor-
tunately got hold of two specimens with seven rings ; whether an accidental
variety, or as Burmeister thinks, one occasioned by the slipping of one
ring under the others, it is difficult to say. Quenstedt, however, relied.
on these, and Dalman’s 7-ringed specimen of O. dilatata, and asserted the
same number for O. Guettardi. But the error in both cases led him
to see the generic affinity between these two allied species, and he dis-
tinctly says that their union with the typical Asaphi is unjustifiable.
Burmeister, in his first edition, set the number of rings right, but con-
founded O. dilatata, which Sars had well distinguished in Oken’s
“Tsis,” (1835), with our species, and adhered to this view in the Ray
edition (1846). Emmerich had, in the mean time, spoken of them as dif-
ferent species, and figured O. dilatata in Leonhard and Bronn’s “ Neues
Jahrbuch,” for 1845. Corda still maintains the error of the seven rings.
British Localities and Geological Range.—LUANDEILO FLAGS only.
Not yet known in North Wales ; the localities given for it in the “ Geol.
Journal,” vol. i., p. 20, &c., are erroneous, and were stated to be so in
vol. ii, p. 128. It abounds in the distorted slates at Shelve and Hope
Mill, Shropshire (Sir R. I. Murchison) ; Rorrington, Middleton, and
Meadowtown, Shropshire ; Builth, Radnorshire; Llangadoc and Llan-
deilo, Caermarthenshire (Geol. Survey Coll.) Haverfordwest ; Muscle-
wick Bay, Pembrokeshire (Phillips). Not yet found in Ireland.
Foreign Distribution —La Couyere, Bain, &c., near Rennes, in the
Cote dor (M. Rouault). In the north of Europe O. dilatata takes its
place. 7

EXPLANATION oF PLATE VI.

Fig. 1. Perfect specimen from Builth (the glabella hardly pointed enough in front).

Fig, 2. Same specimen dissected; at a the slight ascending furrows which cross the
neck segment are seen; b b, cheeks or wings; ¢ ¢, fulcral points of the pleure ; d, tail.

Fig. 8. Under side of head in front, with the hypostome 6 attached to the continuous
under portion a of the cheeks; Builth.

Fig. 4. Young specimen from Builth.

Fig. 5. Border of the tail, the inflected striate portion rendered wavy by projecting
further inwards on each rib. .

Fig. 6. Variety, with the tubercles on the axis strong; Llandeilo,

All the specimens in the Geological Survey Collections.

June, 1849. Jd. WW SALTER. — |

RKingiom.

benlogical Suebep of the Mnited

GC
Vv

oN

OCY GIA PORELOCKn - Sayer

BRILTSsH FOSSILS.

DecapE I]. Puare VII.

OGYGIA PORTLOCKII.

{Genus OGYGIA. Bronentart. (Sub-kingdom Articulata. Class Crustacea. Order
Entomostraca. Family Trilobite). Eyes large, smocth; facial suture cutting the pos-
terior margin ; no rostral shield or vertical suture; hypostome entire ; body rings 8; tail

large. |

Diacnosis. O. ovali-oblonga ; capitis margine angusto; glabella genis
latiore, obscuré lobaté ; oculis ad anteriorem partem capitis positis; sutura
faciali ad frontem marginali; caude axt lato brevissimo.

_ Synonyms. Asaphus dilatatus, Portiock (1832), Geol. Rep., Tyrone,
&e., pl. 24, f. 2 (not of Dalman). Ogygia dilatata, PHituirs, Memoirs
Geol. Survey (June, 1848), vol. ii., pt. 1, 239.

Description.—Length 33 inches; width 2% inches; often larger.
_ General form nearly flat, ovate, widest in front. Head forming rather
more than a semicircle, considerably longer and wider than the tail,
‘but about as long as the thorax; the glabella is as wide as the cheeks
below, and separated by slight furrows from them; it widens and over-
hangs the eyes above, and is abruptly bent down in front, where the
margin is hardly visible. For nearly two-thirds of its length the gla-
bella is marked by lateral furrows, irregular in direction, dividing it
(apparently) into four lobes, exclusive of the forehead and neck lobes.
The neck lobe 6 is broad, and rises higher on each side than in the
middle ; it has two oblique sunk lines, ¢ ¢, rising from the lower angles,
which appear to divide it into a pair of lobes (O. Buchiz has the same
marking). Above this lobe lies the more contracted basal one g,
which does not reach to the margin of the glabella. The second lobe, h,
is wider and more oblique than the third, 2, which is very faintly divided
from the wide transverse forehead lobe a. The fourth lateral lobe, so
distinctly marked in O. Buchii, is absent in this species. Eyes mode-
rate, placed very high up, towards the termination of the facial suture
on the margin; eye-lid semi-lunate, but not constricted above or below ;
eye line turning a little out above the eye, beneath it obliquely down-
wards and outwards, cutting the posterior margin at about half the
cheek’s width; wings moderately large, with a narrow border and a
; [a1. vii. | 2G

D4 ; BRITISH FOSSILS.

smal] spine. Hypostome with the centre gently swelled, and with dis-
tinct concentric furrows on the sides; apex ..... :

The first and last thorax rings are somewhat narrower than those of
the middle ; the axis is widest at top, and there only a little narrower
than the pleure. It is not arched, but flattish, and marked by indis-
tinct tubercles on the sides and middle. The pleure are straight; the
fulcrum indistinctly marked about half-way along them ; the divisions
between the segments not nearly so conspicuous as the oblique straight
furrow which reaches nearly to the end of each. The ends of the
pleure are recurved and pointed, the foremost ones perhaps not quite
so strongly as in our larger figure, the hinder ones as muchas in fig. 2*.

Tail a semicircle, with the upper angles rounded off; the axis hardly
more than two-thirds the length, flattened, conical, the end a little ~
pointed. There are about five distinct ribs on the axis, each obscurely
trituberculate. Lateral furrows four or five, very oblique, the two
uppermost sharp and deep, reaching more than half across the side, with
a secondary one between them, the two or three last very short and
faint. Margin flat. Whole surface of tail crossed obliquely by lines —
which all run down from the upper angles inwards, except near the
edge, where they are concentric; the incurved portion of the tail con-
centrically striate, broad, and indented by the axis. On the pleure
the lines are longitudinal, and form a broad band crossing the segments.
We do not know their direction on the head; the hypostome, however,
is strongly marked by raised concentric threads.

Variations.—In the young state the middle lobe of the thorax and
tail is narrower (of the latter considerably so), and therefore longer
proportionally than in the adult; thus, in our smallest specimens,
fig. 3, the pleure are once and a half as wide as the axis; im fig. 4,
which is older, nearly as wide in proportion. In this stage the tail axis
is not visibly annulated, but the number of lateral ribs is the same as
in older specimens, about four; the upper one is not, however, dupli-
cate. The glabella in the youngest specimens is very obscurely lobed,
and the eyes are thrown even further forward, close to the very narrow
border in front of the glabella. The latter is not incurved in front.

The most interesting point about these young Ogygie@ is, that they
appear to confirm the supposition of the number of segments increasing
with age. Fig. 3, the youngest, has but four segments to the thorax,
and there is no appearance of displacement, the head is not shifted at
all. In fig. 4, a little older, there are seven rings, nor can we think

there is displacement in this case. The tail has turned a little, asona

pivot, pushing the front edge on one side a little under the last ring, — j
but it has opened from that ring on the other side. Had a ring been —
shifted off, and lost in the stone, we might have expected to see an

BRITISH FOSSILS. 5

impression of part of it on this exposed side—but there is none. And
the probability that we have in this case the whole number of rings
is strengthened by observing what takes place in one a little older,
fig. 5*, for in this the last segment is very narrow, and appears to be
in course of development.* We have no perfect very young spe-

-cimens of O. Buchii, and therefore the point is still open to observation

in this genus, in which occasional specimens have certainly been found
with seven rings, as noticed by Quenstedt, Dalman, and Burmeister.
The usual number is eight.

Affinities.—Its identification with O. dilatata by its discoverer, Port-
lock,+ is easily understood by reference to his very imperfect original
specimen, which he saw clearly was distinct from O. Buchit. With
Dalman’s figure, too, there is more similarity than with the better
ficures published since by Sars (Oken’s “ Isis,” 1835), and Emmerich
(“‘ Scientific Memoirs,” vol. iv.) Our species differs from the Swedish
one essentially in the broad glabella, narrow head margin, and forward
eyes. The proportions of the caudal axis and the lateral ribs of the
tail are altogether different, but the above-mentioned characters of the
head will suffice.

British Localities and Geological Range.—LuAaNDEILe FLAGS. Large
and fine specimens were obtained in abundance at Newtown Head,
Waterford ; smaller ones are common at Builth, Radnorshire.

Foreign Distribution—Not known. Dalman’s figure of A. dilatatus
is more like our species than the representations given by Sars and
Emmerich, but we take it for granted these authors figure Brunnich’s
species, as their specimens were from Christiania.

EXPLANATION OF PLATE VII.

Fig. 1. Large, but not full-grown individual. Newtown Head, Waterford.
Fig. 2, Same, or similar specimen, dissected.
_ [The letters on the head are placed in the order of those in the Mem. Geol.
Survey, vol. ii., pt. 1, p. 334. ]

a, Forehead, or front lobe; b, neck lobe, traversed by a pair of oblique lines cc,
which mark the extent of the articulating surface of the first thorax joint; g,
basal, or first lobe; h, middle, or second lobe; 7, upper lobe, third; j, posterior
margin, or lateral neck lobe ; C, free cheek, or wing; 0, margin.

Fig. 2*. Thorax ring of ditto; cc, place of fulcrum; e, an oblique line running up
wards to the furrow (as in O. Buchit).

* We believe this increase in number is not a solitary case. The figured specimen of
Trinucleus Lloydii, Murchison, has but five rings, and seems perfect. It may be peculiar
to certain genera. Burmeister has suggested it in the case of Paradoxides bohemicus.

{+ We have great pleasure in dedicating the new species to Lieut.-Col. Portlock, whose
careful and elaborate treatise on the Irish trilobites will be always valued by the British
student. It was not only the best, but, at its publication, was the only English work

containing extended views of the generic affinities.

4 BRITISH FOSSILS.

Fig. 2**, Tail of ditto; f, line marking the edge of the thin incurved portion of tail
[the lines that cover the tail in this figure are those of the upper surface] ; g, intermediate
furrow between Ist and 2nd.

Fig. 3. Youngest specimen, with four body rings. Builth.

Fig. 3*. The same magnified, to show the narrow caudal axis.

Fig. 4. One rather more advanced, with seven body rings. Builth.

Fig. 4*, The same, &c., magnified; shows the tail a little turned aside.

Fig. 5. Still older; the eyes very forward; eight rings. Builth.

Fig. 5*. The same, magnified: shows the last thorax segment as yet imperfectly deve-
loped a.

Fig. 6. Specimen of intermediate size, with short axis. Waterford.

Fig. 7. Imperfect hypostome; aa, concentric furrows. Waterford.

Note on the Genus.

The near affinity of Ogygia with Brontes has been perceived by Emmerich, who, in his
excellent paper, “On the Morphology and Classification of Trilobites,” * placed it next to
that genus. The number of segments differs, 10 for Brontes, 8 for Ogyyia; Brontes, too,
is sometimes very convex, while Ogygia is flat; the shape of the glabella and caudal axis
differ materially, and there was no genus known which could fill up the interval between
the two genera. Both are expanded forms, characterized by large and strongly radiated
tails, and flattened glabelle, and by an obtuse, entire, furrowed hypostome. We are,
therefore, fortunate in being able to publish a species of Ogygia whose characters link the
genera much closer than before, and which, perhaps, might be regarded rather as a new
generic form, but that its habit is quite that of Ogygia. If we knew more species of the
genus, we would propose sub-genera for it, and might divide it into—

1. Glabella indistinctly lobed; facial suture within the margin. O. Desmarestit,
Brongn. O,. Edwardsii, Rouault.

2. Glabella distinctly lobed; facial suture within the margin. O. dilatata, Dalm.

3. Glabella narrow; facial suture on the margin. O. Buchii, Brongn. O. Guettardi,
Brongn.

4, Glabella broad; facial suture marginal. O. Portlockit.

There are three or four undescribed British species of Ogygia, but at present we know
them only by fragments,

J. W. SanrEn.
June, 1849.

* Leonhard and Bronn’s “ N. Jahrbuch,” 1845, translated in Taylor’s “ Scientifi
Memoirs,” vol. iv. ,

eological Suchep of the Tauted Langdon.

CALYMENE vrepercunosa — Salter

BRIT US e028. SEL 5.

Decave ll. Puate VILLI.

ee

: CALYMENE TUBERCULOSA.

[Genus CALYMENE. Bronenrart. (Sub-kingdom Articulata. Class Crustacea, Order
Entomostraca. Family Trilobite). Axis distinct; glabella lobed, narrower anteriorly ;
facial suture dividing the posterior head angles, submarginal in front; a rostral shield ;
eyes supine (with a thin cornea ?); thorax of 13 rings, formed for rolling. ]

Draenosis. C. lata, depressa, alutacea; margine frontali capitis pro-
ducto recurvo, genis gibbosis, glabella depressé ; thorace ari angusto, pleuris
planis usque ad fulcrum, quod ad dimidium anterius, ad tertium posterius,
positum est; cauda laté, superne depressa, lateribus abrupte deflexis ; axi
conico, subplano, 1-8 annulato, costis lateralibus 5, planis, sulcis acutis.

Synonyms. C. Blumenbachii vera? a. tuberculosa, DALMAN (1828),
p. 86? (not tab. 1, f. 2). C. Blumenb., var. a. tuberculosa. Hisincer
(1837), Lethea Suecica, 10? (not tab. 1, f. 3). C. Blumenb., Murcuison,
(1889), Sil. Syst., pl. 7, f.5 only. C. tuberculosa, Satter (June, 1848),
** Memoirs of Geol. Survey,” vol. ii. part 1, pl. 12.

Almost every author who has written on Calymene Blumenbachii has
hinted his belief that two or more species were to be recognized among
its protean forms ; yet, except Colonel Portlock, who separated the C.
brevicapitata in his report on the fossils of Tyrone, no one has done:more
than point out varieties. An extended examination of very numerous
specimens convinced us that three distinct species were known in Eng-
land, and their characters were detailed in the 2nd volume of the
“Memoirs of the Geological Survey.” Still further investigation of
intermediate forms has shaken this opinion again, and we are at present
wholly in doubt whether the striking differences about to be pointed out
mark only a distinct variety, or are of specific value. At all events, in
giving a typical species of this genus, we would rather present the
reader with a new and well-marked form, than with one so familiar as

that of the famous “ Dudley fossil.”

Description.—Length, about 24 inches, width, 14 inch. Whole sur-
face equally and minutely scabrous. General form broad for the genus,
not much attenuated posteriorly, depressed. Head short, wide; the

[ 11. vili.] 2H

2 BRITISH FOSSILS.

glabella not more prominent than the cheeks, and much narrower, con-
tracted in front, and separated by a deep furrow from the front margin :
it has three lobes on each side, the basal one large, the middle one
nearly spherical, the third mimute ; the forehead lobe is small, the neck
lobe large and prominent. ‘The neck furrow is continued nearly to the
posterior angles, which are rounded. Cheeks gibbous, often more ele-
vated than the glabella, bearing the small eyes on their most prominent _
part. These are placed opposite the middle lobe of the glabella, and at
some distance from it. A strong deep furrow separates the cheeks
from the glabella, except opposite the eye, where a buttress is thrown
across from the cheek, touching the middle glabellar lobe. ‘The wings are
strongly bent downwards, and even inwards on the under surface of the
head, and the anterior margin is much recurved, and produced into a
snout. On looking at the under view of the head, the margin appears
greatly bent, and in the angle so formed the curved rostral shield, half
as long as broad, is inserted ; beneath this is attached the hypostome,
which is squarish oblong with the terminal angles rounded, strongly con-
vex forwards, the convexity terminating in a compressed tubercle ; one or
two concentric lines, as if of growth, mark the surface, which is also ;
scabrous, like the general crust of the body. ‘The axis of the 13 body | ;
rings is convex, but narrower than the pleure, and constantly tubercular ;
on the sides. The pleure are horizontal half way, and then strongly
decurved ; their ends rounded posteriorly, and bent forward. Fulcrum
distant from the axis, abcut, half way from it near the head,—at one-
third, or rather less, behind. Pleure sharply furrowed, the forward or
fulcral half somewhat narrower than the posterior. Tail nearly semi-
circular, with the front angles truncated, evenly and gently convex, the
axis not prominent, the sides decurved strongly towards their edges.
Axis not percurrent, narrow, conical, with seven rings, and a terminal
boss. Lateral ribs flattened, separated by sharp, narrow furrows, start-
ing at a wide angle from the axis, and curved back on the sides, simple,
or but rarely marked by a central line near their ends, —not bifurcate, as
in C. Blumenbachit.
Junior.—The proportions of the axis to the sides and the struc-
ture of the pleure are similar, but the glabella is more cylindrical, not
widened below; the tail is proportionally smaller, has the axis wider
and more convex, with fewer ribs, and there are but four distinct ribs on
each side. Fig. 8* is the tail of a young animal magnified.
Variations—In some the axis is a little more prominent, in others a
greater or less depression of the glabella occurs, and apparently the
production forwards of the snout is not always m the same degree.
But these variations are within narrow limits, and our species never —
seems to approach C. Blumenbachii in convexity, especially with regard

BRITISH FOSSILS. : 3

to the glabella and caudal axis. The front is constantly produced, the
‘surface minutely scabrous, not covered with scattered tubercles, but this
last character occurs in some varieties of C. Blumenbachii, which is
more variable than we formerly believed.

Affinities.—It is distinguished from C. Blumenbachit, with which it
has always been confounded, and to which it is closely allied, by the

broad depressed form, narrow axis,* glabella not higher than the cheeks,
distant fulcrum, and wide depressed tail; the produced recurved snout
also is a strong character. C. brevicapitata has the snout recurved, but it
is shorter ; the axis is prominent, and the fulcrum close to it ; the glabella
also is much shorter and smaller in front, and the whole form is elongate
and cylindrical. With the American species, as published by Green,
Hall, and Emmons, it does not need a close comparison: C. senaria is
attenuated posteriorly, and has a wide head, close fulcrum, and a small
tail, with the axis as broad as the sides: C. callicephala is distinguished
at once by the very short triangular glabella ; it has also a close fulcrum.
It is quite possible that hereafter forms may be found which will con-
nect this species with the more common C. Blumenbachii; but at pre-
sent we do not know such forms, and it is necessary to point out the
obvious characters which distinguish them. Between C. Blumenbachit,
however, and the other British species, C. brevicapitata, specimens
intermediate in character, both as regards form and sculpture, have
been discovered ; the present species, therefore, being founded on some-
what similar kinds of variation, must be received with caution.
History.—The early figures and descriptions of animals of this genus
had, of course, no reference to such minute differences as are now
deemed necessary for specific character; however, there is one early
figure which certainly resembles more the depressed tail of our spe-
cies, with widely spreading and curved side ribs, than C. Blumenbachii ;
we mean that of Linnzus, “ Stockholm Trans.,” 1759, t. 1, f. 3.
Dalman describes, under C. Blumenbachit, three forms,t viz. :—

1. Var, tuberculata, in which he erroneously counts 12 segments to the
thorax, and reckons about seven ribs to the tail. Length, 2 inches to 23.
Gottland and England; the English specimen having the axis of the thorax
tuberculate on the sides, as in the next variety.

2. Var. Blumenbachii vera? a. tuberculosa, with 13 segments, and tail
with about eight ribs, the axis tuberculated on its sides ; the head, tail, and
lateral knobs of the axis closely scabrous; the dorsum (axis itself) smooth.
Length about an inch. Gottland.

* There is a variety of C. Blumenbachit, with narrower axis, found at the Hollies, near
Horderley, but the glabella and tail are normal, and the front not produced.

+ “ Et descriptiones auctorum, et specimina ad hac speciem relata, tantas proebent dis-
crepantias, ut fere credam diversas species sub hoc nomine esse commixtas, de qua re
tamen, ob speciminum inopiam, dijudicare nequeo.”” Dalman, Palead., p. 35.

4 BRITISH FOSSILS.

3. Var. Blumenbachii vera, f. pulchella, “ undique punctis elevatis
sparsis,”’ the axis hardly tuberculate at the sides; small. Gottland.

Of these three forms the first is the most doubtful. Dalman has pro-
bably given a figure of it, bad in all points of detail, in his table 1, fig. 2.
This figure seems a little to resemble our species in the rather narrow
axis, and distant fulcrum, and there is no indication of bifid ribs to the
tail; however, the snout is not produced at all, the axis of the tail is
also broad and convex, so that it probably is intended for the common
species. Of his var. pulchella (tab. 1, fig. 3), we have seen specimens
in the cabinet of Sir Roderick I. Murchison. They are dwarfs of C.
Blumenbachit, and, like it, have scattered tubercles, a large glabella,
and convex axis. But the description of var. 2 in so many respects
agrees with the subject of our plate, that we have adopted the term
tuberculosa as a specific name for it. The close minute scabrosity is
particularly alluded to by Dalman. [ven if the identification be
incorrect, it will not involve any confusion of nomenclature. No
recognizable figure of this species appeared till the publication of the
“Silurian System,” in which, at pl. 7, f. 5, a Burrington specimen is
figured, and in the description the knots on the axis are mentioned as
variable.

British Localities and Geological Position —WENLCCK SHALE to
Urrer Luptow Rocks. Upper Silurian beds, Underbarrow, near
Kendal, Westmoreland (Prof. Sedgwick). It abounds in nodules of the
Wenlock shale at Burrington, Shropshire, from whence thousands of
specimens have been distributed through collections. Small specimens
are plentiful at Usk, Monmouthshire, in Upper Ludlow Rock; in
neither case associated with the more common C. Blumenbachit.

Foreign Distribution.—There is much reason to believe, as before
stated, that it occurs with the better known species in Gottland.

EXPLANATION OF Puate VIII. ~

Fig. 1. Full-grown specimen from Burrington ; the head and tail a little bent down.

Fig. 1*. A specimen from the same locality, partially rolled up, but open sufficiently to
show the hypostome or mouth-piece attached to the rostral shield a.

Fig. 2. Extended specimen from the same locality.

Fig. 8. Dissected head; # is the reflected front.

Fig. 4. Body segment separated, shows the nodular axis, and the distant fulcrum.
Fig. 5. Body segment seen in profile. It shows the depressed form of the body.
Fig. 6. Hypostome highly magnified.

Fig. 7. Magnified portion of the general surface.

Fig. 8. Young animal from Usk.

Fig. 8a. Tail of ditto magnified.

J. W. SALTER.
June, 1849.

DECADE 2. PL.9.

Geological Survev of the United Kingdom. OLENUS
| i (Silurian)
2 4

OLE NU S accRmmrs 2 Svea

Pa ee a: +
E. Forbes durex:

CR.Bone del

BRITISH-FOSS115.

DecapE II. Prate IX.

OLENUS MICRURUS:.

[Genus OLENUS. Datman (in part). Sub-kingdom Articulata. Class Crustacea.
Order Entomostraca. Family Trilobite.) Glabella narrowed anteriorly, lobed; eye
smooth, generally with a narrow prominent ridge connecting it with the upper part of the
glabella; facial suture marginal in front, and cutting the posterior margin behind; no
rostral shield ; hypostome. . . .? pleure 14, or fewer, pointed and recurved ; tail with
articulated axis and sides. |

- [Sub-genus Olenus. Body rings 14; tail entire.]

Draenosis. O. ovatus posterius attenuatus ; glabellé genisque equalibus ;
thorace segmentis 14, pleuris postremis axt angustioribus ; caudé transversa
integra, apice truncato, axi 1-annulato, lateribus unicostatts.

In the course of surveying the barren country south of Snowdon, Mr.
A. Selwyn, of the Geological Survey, discovered fine specimens of this
new Olenus. ‘They were found only at two or three localities in the
lowest fossiliferous beds of the Silurian system, and may be considered,
therefore, as the oldest British trilobites; they were associated with a
species of Hurypterus and a Lingula. The discovery is the more inte-
resting, as Olenus and Paradoxides are among the most ancient genera
of trilobites in the Silurian rocks of the Continent. Other British
species of the group have been described by Mr. John Phillips, from
the black shales of Malvern.

Description.—Length, one inch three-eighths ; width, seven-eighths.
- General form broadly obovate, acuminate posteriorly ; the axis rather
prominent, and the sides flattened. Head more than twice as wide as
long, semicircular, with a narrow equal border, and produced at the
posterior angles into moderate diverging spines. Glabella reaching
very nearly to the front margin, bell-shaped, not very convex, but a
little swelled below, with a narrow neck lobe, and two lateral lobes.
Cheeks a little wider than the glabella. Eyes not large, forward, near
the glabella, and connected with it by a slight oblique prominence.
Kye lime cutting the posterior margin far outwards. Pleure 14, flattish,
increasing a little in width as far as the 6th segment, then shortened
gradually, so that the two last are scarcely wider than the tail ; each
marked by an oblique shallow furrow, deeper near the tips, which are
slightly recurved and produced into short spines. Axis narrowed pos-
[xr. ix. | 7 a1

2 BRITISH FOSSILS.

teriorly, not so wide as the pleure in the anterior rings, but im the
hinder ones wider than the pleure. ‘Tail semicircular, truncate, the
axis convex with one rib above, and about equal in width to the sides,
which also have a single faint rib. Margin entire, slightly raised. But
four specimens have been found, and all more or less distorted.

Affinities —From O. spinulosus, with which the head has considerable
resemblance, the entire truncate one-ribbed tail readily distinguishes it.
O. gibbosus, besides having a triangular, many-ribbed tail, has the gla-
bella not reaching nearly to the front margin, and the eye is placed at a
distance from the glabella nearly equal to the diameter of the latter.
In O. micrurus it is not above half the diameter distant. O. alatus, a
small species, named by Dr. Boeck, has the glabella extended forwards,
but it is very narrow and convex, and the eye is distant. The Olenus
gibbosus (Corda), which, in shape of tail, is very different from Swedish
specimens and Wahlenberg’s description, differs from ours in the wide
and ribbed tail, as well as in the general shape, which is oval, not at-
tenuated; besides other points. We know of no other species with
which it can be confounded.

British Localities and Geological Position.—-Lowrst LLANDEILO
FLAGS (Lingula beds), Trawsfynydd, Merionethshire ; Cwm-y-Swm
mine, Dolgelly, ditto; Marchllyn Mawr, near Llanberis, Caernarvon-
shire.

EXPLANATION OF PuatTE IX.

Fig. 1. Olenus micrurus. Trawsfynydd.

Fig. 2. Same dissected. a, central lobe of the head,* including 8, the glabella, and c,
fixed cheeks; d, the mucronate wings; e, thorax segments, the obscure fulcral points
are at ff; tail, g, with two-jointed axis, and single lateral furrow.

Fig. 3. Small specimen, Cwm-y-Swm mine, Dolgelly.

Note on the Genus.

The group of Olenide (Emmerich) includes genera which differ from each other in the
course of the facial suture; in Paradoxides and Olenus its termination is on the posterior
margin, and the wings or free cheeks are produced into spines. In Peltura (P, scara-
beoides) and Triarthrus, it terminates in the posterior angle, or even a little above it, on
the external margin, and the wings are very small, and by no means produced into spines.

Paradoxides differs from Olenus in the large and clavate, not bell-shaped, glabella; in
possessing 16 to 20 body rings, and a minute tail, with its axis only articulate.

Olenus is divisible into two sections, if these do not merit the name of genera. 1. The
group of true Olenus, to which our species belongs, having 14 body rings, and a tail with
entire margin. 2. O. spinulosus, having fewer, about 12 body rings, and a spinose or

laciniate tail; for the latter species, the sub-generic name Parabolina, in allusion to the

shape of the glabella, might be appropriate.
June, 1849. | J. W. SALTER.

* Corda has proposed to call all this “ glabella,” and to distinguish it into central and
lateral lobes:

a at
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beological Surbep of the United Ringdom.

(Silurian)

AMPYX wupDus __Murchisow

BRITISH FOSSILS.

DecapE II. Prate X.

2 ———

AMPYX NUDUS.

, [Genus AMPYX. Datman. (Sub-kingdom Articulata. Class Crustacea. Order
_ _-_-—s Entomostraca. Family Trilobite.) Glabella tumid, armed with a frontal spine; head
____with simple, unexpanded margins; angles spinous; no facial suture; no eyes; body rings
5 or 6; tail entire-margined, margin deflected ; hypostome ?]

Diaenosis. A. latus; capite semicirculari, spina frontali brevi; angulis
longe-spinosis ; glabella vix producta, lateribus bilobatis ; thorace articulis 6 ;
caudé lateribus 8—9 sulcatis.

Synonyms. Trinucleus nudus, Murcuison (18389), ‘ Sil. Syst.,” p. 660,
ml, 23, f. 5.

Description.—General outline broadly oval; body much depressed ;
the general axis, consisting of glabella, axis of thorax, and axis of tail,
forming a lanceolate, convex, central elevation, narrowing posteriorly.
Head, thorax, and tail of equal length. The first is rounded, with

the outline, in front, slightly prominent, and the whole less than a
semicircle ; the last is slightly triangular. Glabella somewhat claviform,
rounded and convex in front, narrowing behind the middle, and slightly
widening out at its junction with the neck furrow ; it is marked at each

side by two or three indistinct furrows, and, towards its centre, by two

_ very oblique furrows, which form small elliptical elevated spaces, one .
on each side, bounded by rounded and curved folds, below the level: of
the rest of the glabella, and appearing as if distinct from it. From the
front of the glabella projects a slender subulate spine, which, in all
examples hitherto met with, is rather less than the length of the head:
it is not continued as a keel on the central surface of the glabella.
‘The neck furrow is well marked,. and the neck fold elevated. The
cheeks are broad, depressed obliquely in their centres; the depres-
sion proceeds from near the upper extremity of the glabella lobes,

_ __ and continues obliquely outwards, with an obscure curve towards, but

not touching the margin. Between the depression and the hinder por-
tion of the glabella the cheek is gently tumid, and likewise between the
depression and the outer margin. ‘The neck furrow runs straight and

: Hit, x. | 2%

2 BRITISH FOSSILS.

close to the hinder margin of each cheek, leaving the edge elevated as —

a thickened and very narrow rim ; and then, at the angles of the head,
making a slight curve, runs into and furrows the base of a long spine.
This spine is of a subulate form, and projects backwards in a curved
manner from the head angles, and at a distance equal to rather less than
the breadth of the cheek, bends backwards and straight to more than the

tail’s length beyond the posterior extremity. No trace of a facial suture

has been observed in any of the specimens as yet discovered.

The axis of the thorax is convex, and nearly equal in breadth
throughout, very slightly narrowing at its junction with the tail. Its
width is about two-thirds of that of the pleuree. Each joint of the axis
is deeply furrowed centrally, elevated anteriorly and posteriorly, the
elevations of the proximate joints uniting to form a strong convex,
somewhat curved, rounded rib, running across the axis, and terminated
at each side by a conspicuous tubercle. Six such ribs mark as many
thoracic articulations. ‘The axis is separated from the pleure on each
side by a deep but narrow groove. The pleure are straight, narrow,
and depressed, tumid along their lengths on each side of a conspicuous
deep oblique furrow; extremities obliquely truncated, slightly turned
backwards. ‘The surface of the tumid portions of the thorax, and also
of the more convex parts of head and tail, are minutely granulated.

Tail triangular, with the sides slightly curved outwardly. Its axis
prominent, gently tapering for nearly two-thirds of its length, then
becoming parallel-sided, and ending obtusely at the termination of the
tail. Nine ribs like those crossing the thoracic axis, but smaller and
without marginal tubercles, cross the tapering portion of the axis; the
remainder is rmged by numerous minute ribs. The axis of the tail is
divided by a deeply-impressed furrow from the sides, which are gently
convex, and grooved by eight strongly-marked lateral furrows, oblique,
and curved slightly backward; the interspaces are tumid. The upper-
most furrow commences at the junction of the tail with the body, and
proceeds obliquely onwards to the margin, so as to leave a narrow,
lanceolate, triangular space in front of it. The distance between its
marginal extremity and that of the next furrow is greater than the dis-
tance between the extremities of any of the other furrows. The last
and shortest furrow originates just above the termination of the tapering
part of the tail-axis, and between it and the extremity is a smooth and
slightly tumid triangular space. The margin of the tail has an elevated
rim, the deflected portion of which is striated.

Young specimens have the same number of thoracic joints with adult
examples, and do not appear to differ materially in any respect.

The length, exclusive of the frontal spine, of the largest specimen ex-
amined, was one inch and three-twelfths. The frontal spine measured

”

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Kees wee rsa eee s

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BRITISH FOSSILS. 3

nearly five-twelfths. The breadth of the thorax was one inch. The

length of a cheek-spine one inch and five-twelfths.

Affinities.—Its nearest ally is the Ampyx mammillatus of Sars (A.
- Austinit of Portlock), which it resembles in general outline, in form of
head, and features of glabella, and also in the number of thoracic rings.
The tail of Ampyzx mammillatus is, however, very differently shaped, and
has only one lateral furrow on each side, and its axis is, in great part,
smooth. ‘There are also very material differences in the structure of

the cheeks and pleure. Ampyx nasutus (Dalman), is described as

having six articulations, but has a very prominent glabella protruding

- much beyond the cheeks, and a tail represented as smooth at the sides.

The figure given by Dalman, however, so closely resembles the Ampyz
rostratus of Sars (A. Sarsiz, Portlock), that I am inclined to think that
the fold on each side of the tail above the single lateral furrow was
mistaken for a joint of the thorax, for in all the other species of Ampyx
there are only five thoracic segments with the peculiar triangular outline
of the head, which is so shaped in consequence of the great projection of
the front of the glabella beyond the cheeks. These characters we see
combined in Ampyz rostratus, Ampyx Portlockii (Barrande), Ampyx
bohkemicus of Hawle and Corda, and my Ampyx parvulus. The Ampyz

_ Bruckneri of Boll has the same form of head, but the body of that

species is unknown. If, in the end, all the five-ringed species should
prove to have long heads, and those with six thoracic segments to have
short and rounded ones, the latter section may be conveniently distin-

a guished from the former as a subgenus, under the name of Brachampyz.

History—This curious trilobite was discovered by Sir Roderick
Murchison, and figured by him in the Silurian System as a species of
Trinucleus, of which genus he considered it a member, supposing the
border of the head to be lost, and regarded it as allied to his Trinucleus
jimbriatus, but as differing in the number of ribs on the tail. In 1845, a
number of specimens were found in the original locality at Builth by
Sir Henry de la Beche and myself, in more perfect condition than those

first figured, and they proved, without question, to belong to the genus
_Ampyx. On examination of the original specimens figured in the Silu-

rian System, | found that they also exhibited traces of the frontal spine.
The true generic position of this trilobite was afterwards indicated in a
note to the Ray edition of “‘ Burmeister’s Essay ;” that author had re-
garded it as a mutilated example of Trinucleus fimbriatus.

British Localities and Geological Ranges——Nitherto this Ampyz has
occurred only in the LuanperLo Fags of Carneddau Hill, near Builth,

| Radnorshire, South Wales.

4 BRITISH FOSSILS..

EXPLANATION OF PLATE X.

Fig. 1. Figure of the entire trilobite, slightly restored, from the Builth specimen.
All the parts are shown in specimens in the collection of the Geological Survey.

Fig. 1*. Dissection of the species. Lines as if of a facial suture are seen on the glabella,
but they do not seem to indicate any true separation of parts.

Fig. 2. An individual still younger.

Fig. 8. A small specimen, showing the constancy of its characters at an early stage.

Fig. 4. Granulation of the head.

Fig. 5. Granulation as seen towards the extremity of one of the pleure.

Fig. 6. Lineation of deflected surface of tail margin.

Note on the British Species of Ampyz. gt

The genus Ampyzx was first recognized as British by Lieut.-Colonel Portlock, R.E., who
described and figured two species, Ampyx Austinii, identical with A. mammillatus (Sars),
and Ampyx Sarsit, identical with A, rostratus (Sars), and probably with 4. nasutus (Dal-
man). Both these forms were discovered during the researches of the Ordnance Geolo-
gical Survey in Ireland, the former in the Silurian slates of Tyrone, and the latter in
those of Newtown, near Waterford. Recent researches have led to the conclusion that
the strata in which these fossils were found are members of the lower (Llandeilo or
Bala) division of the Silurian rocks.

In Great Britain neither of these species of Ampyzx have, as yet occurred. The only
species described as British, besides that now figured, is my Ampyx parvulus, from the
Lower Ludlow of Vennal Hill (Mem, Geol. Surv., vol. ii. pt. 2, p. 350, pl. x.) There
appears, however, to exist a third species in the Rhiwlas limestone, near Bala ; one dis-
tinct from any as yet described, but of which only heads and tails have been found. The
largest head is half an inch in length, exclusive of the spine. It is nearly allied to A. ros-
tratus, but differs in having much smaller cheeks in proportion to the glabella, which is
even more produced than in the rvostratus, and exceedingly tumid. ‘The cheeks in the
species to which I have compared it are beyond the middle of the glabella; in the Rhiw-
las form never so far as that part. The neck lobe of the latter is narrow, and the tail,
though similar in sculpture, much shorter and wider. The proportions of the cheeks and
glabella remind us of A. Brucknert (Boll in Dunker and Von Meyer’s Paleontogra-
phica, Ist Band, 11 lief., t. xvii., f. 8), but that species has a carinated glabella, and very
broad neck lobe. Ampyzx Portlockti (Barrande), is said to have the glabella much less
elongated than 4. nasutus, and therefore cannot be the Rhiwlas form. A. bohemicus
(Hawle and Corda, t. 3, f. 19), comes nearer, but is represented as having a much wider |
glabella and a proportionately much smaller tail, with no traces of rings on its axis. I
propose to name the Rhiwlas species, Ampyx tumidus.

Ampyzx baccatus, of Portlock, does not belong to this genus.

E. Forzss.
July, 1849.

MEMOTRS

OF THE

EOLOGICAL SURVEY

OF

OOOO OaOOOaec5“0_—a 2 esse

Figures ond Dearigtions

ILLUSTRATIVE OF

BRITISH ORGANIC REMAINS.

DECADE III.

DPD LLOEPLPIELE_ELQO0O0LOOEOOO Ooooh ~

~ ) LONDON:

PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:

PUBLISHED BY

LONGMAN, BROWN, GREEN, AND LONGMANS.
: | 1850.

PRINTED BY W. CLOWES AND 80NS, STAMFOR

. oe: 1 ip
ms . ‘

~ ¥ t ty 4 en re ru

‘ r Fan

NOTICE.

PALHONTOLOGICAL researches forming so essential a part of geological
investigations, such as those now in progress by the Geological Survey
of the United Kingdom, the accompanying plates and descriptions of
British Fossils have been prepared as part of the Geological Memoirs.
They constitute a needful portion of the publications of the Geological
Survey, and are taken from specimens in the public collections, or lent
to the Survey by those anxious to advance this branch of the public
service.

The plan proposed to be followed in the work, of which this Decade
_ forms a part, is as follows :—

To figure in elaborate detail, as completely as possible, a selection of
fossils, illustrative of the genera and more remarkable species of all
classes of animals and plants the remains of which are contained in
British rocks ; to select especially such as require an amount of illus-
tration which, to be carried out by private enterprise, would require
a large outlay of money, with little prospect of a return, and a long
time to accomplish, but which, by means of the staff and appliances
necessarily employed on the Geological Survey, can be effected at small
cost, and with a rapidity demanded by the publication of the Maps and
Memoirs of the Survey; thus, it is hoped, affording an aid to those
engaged in the sciences with which this work is connected, that they
might not otherwise have possessed, and which may materially promote
the progress of individual research,

H. T. De wa Becue,
Director-General.

Geological Survey Office, Jermyn Street,
30th June, 1850.

Phe LESH FOS 5-b 4.5.

DECADE THE THIRD.

Tue third Decade of representations of British Fossils follows up the
subject of the first, and continues the series of illustrations of the
genera and species of extinct Echinodermata, especially those belonging
to the orders Asteriade and Echinide.

The genera illustrated in this Decade are partly new, partly long-
established ; so also with the species, some of the most remarkable of un-
published forms having been selected, as well as some of the commonest
and best known fossils. Yet, even respecting those which are so familiar
that their whole history is believed to have been long ago made out,
there is so much to.be cleared up, so many points of structure hitherto
very imperfectly or not at all elucidated, and such an accumulation of
synonyms, that their investigation is much more laborious, and. occupies
much longer time, than inquiries into entirely new types. Thus, three of
the fossils figured and described in this Decade, Hemicidaris interme-

dia, Galerites albogalerus, and Micraster cor-anguinum, are so familiar

to geologists and naturalists, so abundant and so well preserved, that
authors do not hesitate to cite them without comment, as if they were
free from any obscurity. Nevertheless, I may say confidently, that
not until now has the literature of these well-known and often-described
forms been cleared up, and many of the most important points in their
organization made known. Common as they are, no representations of
them, presenting sufficient details of their structure, have ever appeared
before.

Among the new forms now first described and figured, some are of

singular interest. Two of them, the Lepidaster Grayii and the Tropi-

daster pectinatus, are not only new as species, but unquestionably possess
features entitling them to become the types of new genera. Of those
b

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vl BRITISH FOSSILS.

belonging to old genera, the Uraster Gaveyi is singularly interesting,
presenting, as it does, the spectacle of a Liassic echinoderm, which so
closely resembles the commonest star-fish now living in the British seas,
that it can only be distinguished from it by a minute and critical com-
parison ; and the Hemicidaris Purbeckensis is remarkable as being the
first member of its tribe ever discovered in strata of the Purbeck series.

The species described and figured have been selected from forma-
tions of different geological epochs. From Silurian rocks Lepidaster
Grayii has been taken ; from older secondary strata, the two forms of
Hemicidaris, the Galerites (Holectypus) hemispherica, chosen on ac-
count of its being new to Britain, and also affording an excellent illus-
tration of the sub-genus to which it belongs, and the Dysaster ringens,
selected for the same reasons; also the new star-fishes, species of
Uraster and Tropidaster, already alluded to. Of cretaceous fossils
there are the critical Galerites castaneus, and the characteristic Gale-
rites albogalerus and Micraster cor-anguinum.

A third series of illustrations of the fossil Echinoderms is far ad-
vanced, and in preparation for publication.

Epwarp ForBEs.
June, 1850.

e rar Pgh ved
aH eins 4

Yous

DECADE 3 Pil. 1.

Geological Survep of the Rnrted Kingdon.

ILIEIP LID AST IBIR.
(Silurian )

qareee

4 rave raae anes

LEPIDASTER | Gran Varies

Bapl his Hh FOSSIL s.

DecaveE III. Puare I.

LEPIDASTER GRAYI.

[Genus LEPIDASTER (Aezis, a scale, and acrzp, a star.) ForBEs (1850). (Sub-king-
dom Radiata. Class Echinodermata. Order Asteriade. Family ....?) Body de-
pressed, stellate, many-rayed ; rays short, tapering, covered above with polygonal ossicles ;
below formed of four series of oblong squamose ossicles. ]

Species Unica. Lepidaster Grayi. |

The unique and very remarkable fossil figured in the accompanying
plate has been communicated by Mr. John Gray of Dudley, a gentle-
man to whom paleontological science is indebted for numerous and im-
portant discoveries among Silurian fossils, and whose splendid collection
has been most liberally placed at the service of all engaged in scientific
researches.

At first glance it bears a striking likeness to a star-fish of the
genus Solaster ; its general form recalling strongly the aspect of Solaster
papposa. On a closer inspection the resemblance proves more apparent,
than real, and no near affinity with that genus can be proved. On the
contrary, if not only possesses characters so peculiar as to establish be-
yond question its right to rank as a separate generic type, but even to
render doubtful its position among true star-fishes, and to raise the
question whether it be not a linking form connecting that order of
Echinoderms with the Crinoids.

The disk of our fossil is a very little more than two inches in diameter.
It is, unfortunately, so injured that its elements cannot be clearly made
out, but appears to have had a framework composed of closely-set poly-
gonal ossicula. Around it are arranged the rays, equidistant from
each other, like so many spokes of a wheel. Their average length is one
inch and one-twelfth, and their breadth towards the base four-twelfths.
They are all regularly lanceolate. Their under surfaces are exposed
on the slab, and are composed of thick transversely oblong plates, slightly
overlapping each other in scale-like fashion, and ranged in four longi-
tudinal rows, two on each side of a central or ambulacral groove, which
is itself, towards the extremity, in some instances partially filled up by

Pir. 1. | B

Zz BRITISH FOSSILS.

small polygonal intervening plates. Of the two rows of border plates
on each side of the groove, the inner series is formed of oblong ob-
scurely hexagonal ones, with traces of punctations and grooves on their

surfaces, as if for spines. The ray that is most perfect exhibits —

twenty-five plates in each row. The outer series consists of sub-
orbicular or obscurely polygonal plates, which, like the mner ones, are
gently convex on their surfaces. The upper surface of the ray, and
probably of the body, was composed of numerous small polygonal
nearly flat ossicula, closely set, and of various sizes.

Mr. Gray has dissected from the slab the extremity of one of the
rays in such a manner as to permit an examination of both upper and
under surfaces of the same ray: the result of an examination of the
fragment detached confirmed the above description.

Locality and Geological Position.—This star-fish was found in the
quarries of WEentock Limestone in the Castle Hill, at Dudley. At
the same time, a number of encrinite remains of several species, both
perfect specimens and fragments, were found associated with it. Mr.
Gray states, that after a careful search not even a fragment of another
specimen of this exceedingly curious fossil has been detected.

EXPLANATION OF THE PLATE.

Fig. 1. The entire specimen of Zepidaster Grayi ; its under surface is exposed on the
slab.

Fig. 2. Upper surface of the extremity of a ray ; greatly enlarged.

Fig. 3. Under surface of the same ray.

EDWARD Forens.
June, 1850.

= os

DECADE 3.PL.2.

Heological Surbev of the United Kingdom,
4 ) (Oolitic)

Pige <wePrryesy|

s Firsze

URASTER GAVEYI__ forbes

BPETLS HH: OSS PES.

DecapeE III. Puare II.

eee

URASTER GAVEYI.

[Genus URASTER. Acassiz. (Sub-kingdom Radiata. Class Echinodermata. Order
Asteriade. Family Urasterix.) Body stellate, five rayed; a vent on the dorsal surface ;
rays rounded, surface spinous; ossicula small, compressed, irregular, reticularly combined;
ambulacra bordered by three sets of spines; suckers quadriserial. The genera AsTERA-
CANTHION of MiLLER and TroscHEeL, and ASTERIAS (restricted) of J. E. Gray, are

synonymous with URAsTEr. |

Draenosis. UW. brachiis quinis, lanceolatis; pagina superiori valde

spinosa, spinis brevibus, teretibus; ossiculis ambulacralibus linearibus,

arcuatis, carinatis, carina extus sulcatd intus fossata.

Description.—This remarkable star-fish is of the shape and dimen-
sions of the common living Uraster rubens, to which it presents also
a striking resemblance in the details of its structure. Indeed, were
this lias fossil to be resuscitated and cast upon our shores now,

the British naturalist would see in it only a new but by no means

surprising form of Uruster, having close affinities with, and requiring
to be distinguished by critical characters from, the commonest of our
native Asteriade.

‘The under surface of the specimen is the one exposed, but sufficient
of the upper side is exhibited at the sides of the arms to show its
structure and armature. The whole of the upper surface of the rays
and disk appears to have been covered with .thickly-set, rather short,
tapering spines, mingled with smaller and slenderer ones, and traces
of pediceilarie. ‘The ambulacra are bordered by closely-set narrow
plates with steep inner sides, and having their upper surfaces convexly
curved and indented by about five depressions, indicating the sockets of
as many rather short, slender, and rounded marginal spines. The
ambulacra themselves are rather wide and flattened ; down the centre
of each is a shallow grove marking the line of junction of the ambula-
cral ossicula. ‘These are very narrow and linear in shape, slightly bent,
with the appearance of a very shallow sigmoid curve. ‘This is caused
by the curved keel which runs down each, grooved throughout two-
thirds of its length, but depressed and marked with two pit-like

(tir. 11. |

2 BRITISH FOSSILS.

impressions in the neighbourhood of the ambulacral sulcus; the ends
of the ossicula which go to form the sulcus are slightly denticulated.
The curvation of the ossicula has reference to the disposition of the
suckers, which in this genus are arranged in four series down each
avenue. ‘The perforations are slightly ovate in this species.

/ Dimensions.
Inches
Breadth of disks.) ce) sc ee) A ete es Ta) eae
Maximum breadth ofaray . . wah Geral aie hese a
Maximum breadth of an ani Bhlaerbet eS Pais wig iy) i

Length of a ray from angle of junction with the ‘bode: Pa Ni

Length of an ambulacrum from its origin at the mouth . . . 4
Affinities.—This species, as I have already indicated, approaches
more nearly to the existing Uraster rubens and its allies than to any
described secondary or paleozoic fossil. The Asterias lumbricalis and
the Asterias lanceolata of Goldfuss, both from the jurassic beds in

Germany, have been referred by me to the genus’ Uraster,* but they

are imperfect forms at best, and possibly, when found in more com-
plete condition, may prove to belong to other generic types. Not so
with the star-fish now described; there can be no mistake about its
generic position and affinities, as the most essential part of its osseous
framework, the ambulacral skeleton, is perfectly preserved.

Locality and Geological Position—The only specimen hitherto
found of this singular and beautiful fossil occurred in the Lias beds
laid open during the excavation of Mickleton Tunnel, in Gloucester-

shire. It was discovered by Mr. G. EH. Gavey, civil engineer, of

Chipping Campden, Gloucestershire, who most liberally communicated
it for description and delineation to the Geological Survey. It lies on
the surface of a sandstone associated with fragments of Pentacrinites,
small Ammonites, Avicule, and small univalves.

DESCRIPTION OF THE PLATE.

Fig. 1. The fossil, natural size.
Fig. 2. Plan of the ambulacral plates and their spiny borders.
Fig. 3. Diagram of the same parts in the living Uraster rubens, introduced for comparison.

EDWARD ForBEs.
June, 1850.

/

* See “Table of Fossil Asteriade” in vol. ii. pt. 2, p. 481, of the “ Memoirs of the
Geological Survey of Great Britain.”

DE'CADI SeBise

a

beolsgical Surbev of the Hnited Kingdou. TROPIDASTER
(Oolitic)

TROPIDASTER PrectInatus __ Forbes

BRITISH -F OSS 1L Ss.

DecapeE IIJ. Puare Il.

———

TROPIDASTER PECTINATUS.

[Genus TROPIDASTER (new.) Forpes (1850.) (cewass, a keel, and aerng, a star.)
(Sub-kingdom Radiata. Class Echinodermata. Order Asteriade. Family Asterie.) Body
stellate, five-rayed [a vent on the dorsal surface?]; rays convex and carinated above, the
carina composed of a double series of squamose plates; rest of the dorsal surface spinous,
spines simple; ambulacra bordered by transverse plates with spiniferous crests on their
anterior margins; ambulacral ossicula rather, broad, geuiculated, pectinated at their
inner extremities. (Suckers biserial.) ]

Srecies Unica. Tropidaster pectinatus.

Description.—The general aspect of this star-fish when seen from
above is that of a Uraster, whilst viewed from below it resembles an
Astropecten. The rays are rather short, about equal in length to the
breadth of the disk, ovato-triangular. The upper surface of the rays
and disk is covered with short obtuse simple spines, which, on the
sides of the rays, are ranged in oblique rows of about five or six in each
row. Placed rather laterally on the disc is seen, though obscurely, a
madreporiform plate, and I think I can perceive indications of an anal
pore. Down the centre of each ray runs a keel composed of two rows
of squamous plates, somewhat quadrate in form, but produced at their
anterior and inner angles. This kind of keel, or mid-rib, is not
present in any star-fish, recent or fossil, with which I am acquainted,
and resembles in form and structure the tiling of the crest of the roof
of a house. It must be regarded as a peculiarity of generic value.
The rays themselves appear to have been very flexible, and not much
liable to injury. ‘Their extremities are rather pointed. On the under
surface their centres are occupied by the rather broad lanceolate
ambulacral grooves running from the mouth; that orifice is some-
what contracted by the encroachment of the large twin triangular
plates with punctated surfaces which occupy the angles formed by
the junction of the bases of the rays. ‘The ambulacral ossicula are
oblong, rather broad, strongly geniculated in the centre at their
anterior margins, and denticulated by about five crenations at the edge
which borders the ambulacral sulcus. The margins of the under
surfaces of the rays are bordered by transverse, oblong, rather narrow

(rm ia. | B

2 BRITISH FOSSILS.

plates, each bearing a crest at its anterior border indented by the
sockets of eight or more rather short cylindrical spines, which have
rugose surfaces. It is these crested marginal plates with their rows
of spines which give the under surface so much of the aspect of an
Astropecten.

Dimensions of the largest Specimens.

Diameter from apex of one ray to that of the one most distant. . . 1%

Breadth of disk 0 2163.0 te se, he ita to ee anes

Breadth ofa rdy.at origin ¢ 06) eee hee eS eine

Length of a ray fromangle of junction ~.. s. 87. 2 2k te, px:
Breadth of largest inferior marginal plate. =. . 5. « « « » O8
Length of marginal spine, rather more than. .« . - «. « © « OF

Locality and Geological Position This remarkable star-fish was
discovered by Mr. John Gavey, civil engineer, of Chipping Campden,
in the Lras of Mickleton Tunnel, Gloucestershire. Several specimens
occurred, and some fine examples, presented by that gentleman, are
displayed in the cabinets of the Museum of Practical Geology.

DESCRIPTION OF THE PLATE.

Fig. 1. Large specimen; ventral surface displayed.
Figs. 2 and 3. Dorsal surfaces of two smaller examples.
Fig. 4. Dorsal surface of a ray and part of disk, showing the keel-plates and their
arrangement.
Fig. 5. Ventral surface of a ray and part of disk showing the ambulacra and angle-
plates.
Fig. 6. Ambulacral plates and spiniferous plates bordering the ambulacra.
Fig. 7. Margin plates.
Fig. 8. Madreporiform plate.
Fig. 9. A spine.
Figs. 4 to 9 are highly magnified.

EDWARD ForBES.
June, 1850.

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HEMICIDARIS

ve

BRITISH FOSSILS.

DecaveE III. Puare IV.

HEMICIDARIS INTERMEDIA.

[Genus HEMICIDARIS. Acassiz. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Cidarites.) Body sub-globose ; interambulacral segments very
broad, bearing (few) primary perforated tubercles placed on crenated mammillary eleva-
tions ; ambulacral areas very narrow, furnished with primary tubercles on their lower
portions; pores in single file, except close to the mouth, where they are ranged in threes ;
summit crowned with a disk composed of five ovarian and five ocular plates surrounding
a central anus ; spines of two orders, the primaries long, cylindrical, mostly of considerable
dimensions, the secondaries small, compressed. |

Diacnosis, WH. testé subglobosd, areis ambulacralibus infra tuberculis
majoribus confertis, interambulacralibus tuberculis approximatis; spinis
subteretibus, cylindricis, longitudinaliter striatis, strits minutis, basi tumido.

Synonyms. Variation of Cidaris papillata, Parkinson, Organic Re-
mains, vol. iii., p. 14, pl. 1, fig. 6; and pl. 4, fig. 20. Cidaris intermedia,
Fremine, Brit. Animals, p. 478 (1828). Hemicidaris crenularis, Morris,
Cat. of Brit. Fossils, p. 53 (1843).—BuckMAN and STRICKLAND’s Edition of
Murchison’s Geology of Cheltenham, pl. 13 (1845).

The most common example of the genus Hemicidaris in British
collections, is the species before us; the abundance and perfection of
_ Specimens rendering it a favourite fossil. It is usually regarded as the

Cidaris crenularis of Lamarck, and is cited under that name in memoirs
and works on English geology. For the following reasons, however, I
feel obliged to reject the appellation of crenularis as applied to the
English species, and to omit the usual citations and references to
Lamarck and older authors, and to Goldfuss, Desmoulins, Agassiz, and
~Desor.

In the ‘Description des Echinodermes Fossiles de la Suisse,”
Agassiz has described at length and figured the Hemicidaris crenularis
of Switzerland as the species of Lamarck and other authors. He has
presented a specimen in remarkably perfect condition, its spines being
entire. ‘The figures are excellent, but the species, as the spines plainly
show, is not the so-called crenularis of British geologists. As the
bodies of the two species can only be critically distinguished from each
other—unfortunately a frequent case in this genus—it is difficult to
know to which the figures of Goldfuss, and the imperfect older repre=

[zu1. iv. ] : B

2 BRITISH FOSSILS.

sentations of Bourguet and Knorr should be referred. But the figure in
Parkinson’s “ Organic Remains” (Pl. XLIIL., fig. 6) of a “ mammillated
echinite from Wiltshire,” unquestionably represents the species under
consideration, though usually quoted as identical with the crenularis of
Agassiz. The figure in Pl. IV., fig. 20, of the same work, repre-
senting a Wiltshire fossil with its spines, seems to me to belong to this
species also, though it does not appear to have been cited as such ©
except by Phillips in his “ Geology of Yorkshire.” In Dr. Fleming’s
“ History of British Animals,” the name Cidaris intermedia is applied
to the former figure. Now as Lamarck expressly mentions that his
Cidaris crenularis came from Switzerland, and as the Hemicidaris
crenularis of Agassiz may fairly be regarded as that species, whilst it
has been fully described and figured, and is certainly distinct from
the British one, I propose to use Fleming’s name of intermedia for the
latter, and leave crenularis to that of Agassiz; thereby confusion
. will be avoided in future. Dr. Mantell has copied the figure of the
Swiss species in his ‘“ Medals of Creation,” vol. i. p. 840, remarking,
however, that though usually identified with Parkinson’s, he had never
seen specimens in the English oolite like that figured by Agassiz.

| Hemicidarts crenularis is sub-globose, varying from a depressed spheroid
to a barrel-like shape. Its surface is elegantly studded with very pro-
minent and large bosses bearing on their crenulated summits the perforate
spiniferous tubercles. The ambulacral areas are very narrow at their
summits, but gradually widen out in their course downwards, and
immediately at the margin of the mouth are equal in diameter to the
buccal ends of the interambulacral spaces. ‘The latter are widest in
their centres, and gradually narrow towards each end. Lach inter-
ambulacral area is occupied by two rows of tubercles, each row in-
cluding from six to eight, and as there is one of these tubercles on each —
interambulacral plate, the total number of plates in each area is from
twelve to sixteen. Each plate is mainly occupied by the boss and its
areola, the latter bemg quite smooth, and occupying less than half of
the width of the former, which is also smooth, distinctly separated from
the areola, very prominent, and depressed on its summit, where it
is strongly crenulated around the base of the spheroidal deeply-
perforated spiniferous tubercle. The tubercle is in diameter rather
more than the breadth of the areola. The areolated spaces of the
several plates are confluent; consequently on the upper and lower
edges of the interambulacral plates there are no granules. But along —
the edges of both sides of each plate, there 1s a conspicuous row of small
but well-marked perforated secondary tubercles, partially separated from
each other by one or two granules. There are seven or eight of these
on each edge of the larger plates. ‘This produces the effect of a

BRITISH FOSSILS. a

sinuous elevated space ornamented with a double row of granules
(secondary tubercles) running down the centre of each interambulacral
area, and a similar single row separating the ambulacral area on each
side from the poriferous avenues. The ambulacral areas bear very
small spiniferous tubercles compared to those on the interambulacrals.
On their upper and middle portion the tubercles are very small, but
just below the largest interambulacral plate increase suddenly, then
gradually diminish as they approach the mouth. There are about seven
in a row (or fourteen in each ambulacral area) of the larger tubercles,
of which, however, those nearest the mouth are as small as the
ambulacral tubercles of the upper and middle portions of the area.
Like the large primary bosses of the interambulacral plates, those of
the ambulacrals also are crenulated at their summits below the per-
forated tubercles which crown them. The lower and larger ones are
separated from each other by a few occasional granules, the upper ones
are more distinctly bordered by minute granules. As there is only one
spiniferous tubercle to each ambulacral plate, the effect of the ambu-
lacral area is that of a widening space studded by closely-set tubercles,
ranged in two rows, and suddenly increasing in size at the lower
margin of the sides of the test. The avenues of pores are slightly
sinuous ; the pairs of pores are ranged in single file as far as just below
the sudden increase in the size of the ambulacral tubercles, when they
become irregular and arranged in oblique rows of three pair in each.
There are five or six of such rows extending to the mouth and causing
the avenues to widen out considerably in the buccal region. There are
nine or ten pair of pores opposite each of the larger plates.

The mouth is very wide, occupying three-fifths of the under-surface ;
its margin is deeply notched and reflexed at the junction between each
interambulacral series of plates and the poriferous avenues. ‘There
results a division of the mouth-margin into ten segments, five (those
opposite the ambulacral spaces) wider than the other five.

The genital disk occupies a fourth of the diameter of the test. It is
pentagonal, composed of five genital and five ocular plates. Three of
the former are larger than the other two; one of the three is the
madreporiform plate. ‘There is not so great a disparity in the dimen-
sions of the ocular plates. The effect of this arrangement is to cause
an eccentricity of the anal perforation. Both genital and ocular plates
are irregularly studded with numerous small granules. The genital
pores are placed in the lower portions of their plates. The eye-holes
are very minute, marginal, and opposite the truncated ends of the
ambulacral spaces.

The primary spines are long, tapering, and nearly cylindrical ; the
larger ones grow to a length more than twice that of the diameter of

4 BRITISH FOSSILS..

the body. They are minutely and closely striated throughout their
length, but the strize are rather broader than the raised interstices.
The base of each spine has a narrow elevated fold surrounding it above
its ring of crenulations, which are numerous, oblong, and closely and
regularly set. The secondary spines (those surrounding the primaries
on the interambulacral areas and entirely occupymg the ambula-
cral spaces) are very small, compressed, rather spatulate and longitu-
dinally striated. One of the largest measured two-tenths of an inch
in length. I have seen traces of pedicellariz, but not sufficiently
perfect for description.

Locality and Geological Position.—This species is very abundant, and
found in a beautiful state of preservation in the Corat Rae of Calne.
It is scarcer near Weymouth. It occurs also in the same stratum at
Malton, and is recorded from the Coral Rag of Yorkshire by Professor
Phillips. Mr. Buckman has figured a remarkably fine specimen from
the neighbourhood of Cheltenham. In consequence of the doubts
hanging over the identification of the British with the foreign Hemicr-
daris crenularis, I do not venture to give its foreign distribution.

EXPLANATION OF THE PLATE,

Fig. 1. Middle-sized specimen of the sub- -depressed form of Hemicidaris intermedia seen
in profile; an outline of the tall variety, from a specimen in the British Museum, is drawn
around it.

Fig. 2. Dorsal surface; and Fig. 3, ventral surface of the same specimen.

Fig. 4. Ambulacral and interambulacral plates and their sculpture, taken from the
centre of the sides.

Fig. 5. Ambulacral and interambulacral “ibis of the neighbourhood of the mouth.

Fig. 6. A single primary tubercle.

Fig. 7. Genital and ocular disk.

Fig. 8. Spines from a specimen presented to the Geological Survey by Mr. Clark of
Sandgate.

Fig. 9. Base ofa primary spine magnified.

Figs. 10 and 11. Small secondary spines.

Figs. 4—7 and 9—11 are magnified,

Epwarp ForsBEs.
June, 1850.

DECADE Ge) Pilger.

2:
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®eologieal Survey of the Mnited AKmgdom. RUEM CLIDAIRIS
( Oolitic)

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HEMICIDARIS PURBECKENSIS. /o7rbes.

BRITISH POS SIS.

DecapE III. Puate V.

HEMICIDARIS PURBECEENSIS.

[Genus HEMICIDARIS. Acassiz. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Cidarites.) Body sub-globose. Interambulacral segments very

broad, bearing (few) primary perforated tubercles, placed on crenated mammillary

elevations; ambulacral areas very narrow, furnished with primary tubercles on their
lower portions; pores in single file, except close to the mouth, where they are ranged in
threes ; summit crowned with a disk composed of five ovarian and five ocular plates sur-
Pandang a central anus; spines of two orders, the primaries long, cylindrical, mosey of
considerable aiacaons, the secondaries small, compressed.

Hemicidaris Purbechensis. Sp. Nov.
Diaenosis. H. testé subglobosd, arearum ambulacralium infra tuberculis

majoribus remotis; interambulacralium mnumerosis (8), subdistantibus ;
spinis sub-compressis, levibus, ad basin per spatium angustum striatis.

The species of Hemicidaris are difficult to distinguish from each
other, unless we have their spines as well as test before us. Fortu-
nately, in the present instance, we have both; although the specimen
figured is unique. The body at first glance might be confounded with
that of Hemicidaris intermedia, but on closer examination presents dis-

tinctive characters, the value of which is confirmed when we see the
wholly different features of the spines.

The body is sub- -globose, depressed above, but probably, like its con-
geners, liable to variation in this respect. ‘The interambulacral areas
are, about the centre of the sides, rather more than three and a-half
times the width of the ambulacral spaces in the same region. On each
interambulacral plate there is a primary tubercle, erected on the cre-
nated summit of anelevated smooth boss, surrounded by a smooth and
defined areola. The ambulacral and centro-sutural sides of this areola

_ are marginated by rather scattered rounded granules, but not the upper

and lower margins, where the areole of contiguous plates may be said

to be in contact. The areola is wide in comparison with the boss.

There are about eight-primary tubercles in each row, gradually increas-

ing in size as they approach the centre of the sides of the body. The

ambulacral spaces bear in their upper portion, and for two-thirds of
[ur. v.| B

2 BRITISH FOSSILS.

their length, small secondary perforated tubercles on minute bosses,
one to each plate, with scattered granules between them. On the
lower third of the ambulacral areas these suddenly increase in size
to twice the dimensions of those above. The large ambulacral tubercles
are diffusely arranged, so as to alternate with considerable interspaces.
The avenues of pores are slightly undulating. About nine pores
correspond to an interambulacral central plate. The mouth in our
only specimen is concealed, and the apical disk not preserved.

The spines are quite smooth, slender, and subcylindrical, slightly
compressed at the sides. There is a short longitudinally striated well
defined space above the swollen crenated neck. ‘The articulating base
is small. |

The diameter of the specimen is one inch and two-twelfths. ‘The
diameter of the largest spine found is one-tenth of an inch. :

Affinities and Differences—Hemicidaris Purbeckensis differs from
H. intermedia and crenularis in having smaller and more numerous
tubercles, in proportion to the size of the body, on the interambulacral
areas, and a larger granulated intermediate space in their centres ;
the large tubercles on the ambulacral areas, instead of being closely
set as in both the species named, are scattered and alternating ;
the number of pairs of pores opposite each large interambulacral plate
are fewer. The ambulacra are nearly straight, instead of being undu-
lated. Above all, the spines are quite distinct in their characters.

It differs from H. stramonium, a Portland oolite species, said by
Mr. M‘Coy to occur in England, in having a greater number of large
ambulacral tubercles, wider ambulacral areas, and much smaller inter-
ambulacral tubercles.

_ From H. mitra, also a foreign Portland oolite species, to which, like
the last, it approaches in the straightness of the ambulacra, it differs
in the arrangement of the interambulacral tubercles.

H. diademata and Thurmanni, foreign Kimmeridge species, have
fewer interambulacral tubercles. The peculiar structure of the ambu-
lacra of H. alpina sufficiently distinguish that species.

Since, except in the cases of intermedia and crenularis, the spines of
the species I have mentioned are unknown, it is probable that when they
shall have been found, the differences indicated will be accompanied by
still more important distinctions.

Locality and Geological Position —This Hemicidaris is peculiarly in-
teresting as being the first Hchinoderm ever found in the PurBEcks.
It was discovered by myself at Swanage in Dorsetshire, in December,
1849. For several daysI had found the spines of an urchin with which

I was unacquainted among the marine fossils which occur in a zone on -

the summit of the well-known ‘“ Cinder-bed,” composed chiefly of Ostrea

t

a

a

per ale os Ue aN ah Sari a

BRITISH FOSSILS. . 3

distorta, and constituting a conspicuous stratum in the middle division
of the Purbecks. A careful search, during which I was rewarded by
the discovery of several new forms of marine Purbeck mollusca, resulted
in the finding of a very perfect specimen of the body of the Hemici-
daris, now first described, accompanied by its spines, identical in struc-
ture with those previously observed. I have seen no traces of any other
Purbeck echinoderm.

EXPLANATION OF THE PLATE.

Fig. 1. Body of the Hemicidaris Purbeckensis.

Fig. 2. Ambulacral and interambulacral plates.

Fig. 3. Base of a spine, natural size, 3a, magnified. 36 its section.

Figs. 4 and 4a. Portions of the spines, natural size, indicating the dimensions and
proportions of those organs.

Note on the Species of Hemicidaris found in British Strata.

At the time of the publication of Mr. Morris’s “‘ Catalogue of British Fossils” one spe-
cies only of Hemicidaris was known as British. Since then two others have been enume-
rated by Professor M‘Coy, in his paper “ On some New Mesozoic Radiata,” published in
the “ Annals of Natural History ” for December, 1848.

I am acquainted with the following :—

1. Hemicidaris intermedia, Fleming ; H. crenularis of British catalogues; common in
the coralline oolite of Wiltshire; rare in Dorsetshire.—(See Decade III., pl. 4.)

2. Hemicidaris Purbeckensis, Forbes; the new Purbeck species now first described
and figured. :

3. Hemicidaris alpina, Agassiz. (Echin. Suiss. ii., p. 52, tab. 18, figs. 19-22.) A pretty
species, easily distinguished from its congeners by the very small and thickly-set ambu-
lacral tubercles. Our attention has been called to it by Mr. S. P. Woodward. It was
found in the forest marble of Pickwick, Wilts, by Mr. Lowe of Chippenham.

4, Hemicidaris pustulosa, Forbes. A very fine new species from the great oolite of
Minchinhampton. It forms part of the collection of Mr. Lycett, and is figured in Plate A,
fig. 8, of the Monograph of Great Oolite Fossils to be published by the Paleontological
Society. Its nearest ally is the Hemicidaris diademata of Agassiz, which it resembles in
the sudden diminution and very small size of the uppermost interambulacral tubercles,
but differs in having the sutural granulated space of the interambulacral areas very wide.

5. Hemicidaris tcaunensis, Cotteau. (Echin. Foss. du Dep‘. de l’Yonne, plate 3,
figs. 1-5.)? Ihave provisionally identified with the species cited a great oolite urchin
from Minchinhampton, in Mr. Lycett’s collection. It is figured in plate A, fig. 9, of the
Monograph of Great Oolite Fossils, published by the Paleontological Society.

6. Hemicidaris confluens, M‘Coy. In the Monograph already quoted a great oolite
Minchinhampton urchin is figured in plate A, fig. 10, which seems to agree with the
description of this species.

7. Hemicidaris, Sp. Nov.? In the collection of the Museum of Practical Geology.
Found in the cornbrash in a lane leading from Stourton Caundle to Lower Woodacre,
by Mr. Bristow, of the Geological Survey. This is a fine species, very distinct from
any other British one, resembling most nearly H. intermedia, but differing in having

gradually (not suddenly) increasing ambulacral areas, with the tubercles upon them set

4 BRITISH FOSSILS.

well apart, except below, where the larger ones are closely packed. Until the spines
shall have been discovered I hesitate to give a name to this form since it so closely
agrees with the figure of the Swiss H. crenularis.

&, Hemicidaris, Sp. Nov.?—A small depressed form, with very large interambulacral
tubercles, and the larger tubercles upon the ambulacral areas occupying half their length.
It is imperfect, but probably distinct. It was found in the cornbrash in Dorsetshire, and
is contained in the Museum of Economic Geology.

The following I have not seen :—

9. Hemicidarts stramonium, of Agassiz; said by Professor M‘Coy to be found in the
coralline oolite of Calne, Wilts. On the Continent it is known only from the strata above |
the Kimmeridge.

Epwarp Forses.
June, 1850. . 2

DECADE 3. PL. 6.

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GALERITES (HOLECTYPUS ) HEMISPHARICUS __dgasstZ.

BRITISH FOSSILS.

DecaveE III. Puate VI.

GALERITES (HOLECTYPUS) HEMISPHAERICUS.

[Genus GALERITES. Lamarck. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Cassidulide.) Body mere or less hemispherical, always tumid ;
ambulacra simple, continuous, radiant; mouth central, inferior; anus inferior or sub-

marginal; tubercles perforate. |
[Sub-genus Holectypus. Body hemispheric, circular ; tubercles in regular series;

inside without ribs.]
Synonyms. Discoidea hemispherica, AGAssiz, Cat. Syst., p.'7. Dxsor,
Monog. des Galerites, p. 71, pl. 8, figs. 4-7 (1842). Holectypus hemi-

sphericus, AGassiz and Dersor, Cat. Raisonné des Echinides, Ann. des

Sciences Nat., 3rd Series, vol. vii., p. 146.
Var. B. Depressus. Discoidea marginalis, M‘Coy, Ann. Nat. Hist.,
2nd Series, vol. ii., p. 413 (1848).

Var. y. Conicus, anus valde marginalis. Holectypus devauxianus
Cotrrau, Etudes sur les Echinides Fossiles, p. 46, pl. 2, figs. 7-9 (1850).

Diaenosis. G. (H.) testé tumidé, hemispherica, plus minusve depressa,
margine rotundato; ano marginali ; tuberculis in facie ventrali crebris, ad
orem semsim majoribus.

The genus Holectypus has been founded by M. Desor for such
oolitic Galerites as have the aspect and regular arrangement of tubercles
distinguishing the genus Discordea, but have not the internal ribs which
cause such deep indentations in the casts of specimens of the latter
group. ‘They constitute a transition from the Discoidee to the typical
Galerites, and, according to my views, form a section or sub-genus of
the genus Gralerites, more valuable on account of their paleontological
merits and limited distribution in time (being in the main character-
istic of the oolitic period) than for the zoological importance of the
characters of their organization, which are rather transitional than dis-
tinctive. )

The type of the sub-genus Holectypus is the Galerites depressus, a
fossil very abundant in British oolites, and having wide vertical and
horizontal range. The species now figured is conspicuously distin-
guished from G. depressus by having a marginal instead of a vertical
anus, and the tubercles of its under surface very numerous and gradu-

[a11. vi. | B

2 BRITISH FOSSILS.

ally enlarging towards the mouth, instead of being comparatively few
and suddenly becoming large and scattered in that region. Its body is
also more rounded and tumid at the margin, although that character
varies slightly according to the degree of convexity of the dorsal sur-
face.

The only Holectypus described in the Monograph of the Galerites by
Desor, with a marginal anus, is the H. hemisphericus, and the figures
and description given by that author are sufficiently characteristic of the
British species now under examination, so that I do not hesitate to adopt
Desor’s name. Its general outline is sub-hemispherical, varying in con-
vexity in different individuals. Specimens are. rarely quite regularly
convex, but most commonly have a slight obliquity, and are very
slightly elongated and declining on the side towards the anus; conse-
quently the vertex in such examples is not quite central, though con-
stantly apical.* The sides are gently tumid, so as to round off the
margins gradually. The ventral surface is more or less hollowed out
in the centre, often very much so. In the depth of the concavity, and
nearly or quite central, is the mouth, occupying less than one-third of
the disk, round, with ten deep marginated notches separated by gently
curved interspaces, and placed close to the junctions of the interambu-
Jaecral areas with the ambulacral avenues. ‘The ambulacral areas are a
third or more of the breadth of the interambulacrals, their proportionate
dimensions increasing generally with the altitude of the individual, and
lessening usually with age and size. ‘The pairs of pores of the avenues
are ranged in single file; they are slightly more distant from each
other on the under than on the upper surface, but those very near the
mouth are closely set again. ‘There are about four pairs, or four and
part of a fifth, opposite each interambulacral plate towards the middle
of the upper sides. In a specimen slightly above an inch in diameter, I
counted twenty-six interambulacral plates in a series, and ninety-four
ambulacrals, each of the latter representing a pair of pores. Each of
the interambulacral plates is thickly studded with minute granules, in the
midst of which are the spiniferous tubercles, scattered and varying in
number in different individuals. I have found some specimens, closely
alike in all other respects, varying in the number and arrangement of
these tubercles, of which there are sometimes two rows on a plate, at
others only one. In those examples which present the most regular
arrangements, the tubercles are so disposed on the assemblage of inter-
ambulacral plates, that each half area exhibits a curved line of them
rising to alternate at the suture with a similar curved line on the
corresponding half area. On the ambulacral areas the tubercles

* JT use the term “vertex” to denote the highest point of the back, and “ apex” to indi-
cate that point to which the ambulacra converge and where we find the ovarian disk.

BRITISH FOSSILS. 3

are also present, forming more or less regular oblique rows of three,
sometimes of two, and with but slight traces of arrangement. The
tubercles become crowded towards the margin, and are thickly distri-
buted on the ventral surface, very regularly increasing in size towards
the mouth, immediately around which they are often fewer again and more
wide apart. Each tubercle is perforated on its summit, and has its base
borne upon an areolated boss. In very complete specimens, the margin
of the areola is surrounded by a ring of areolated granules, which, when
highly magnified, exhibit traces of perforations on their summits, as
represented | in the plate. The spines are unknown.

The apical disk is formed of five genital and five ocular plates. The
odd genital plate, that opposite the anal interambulacral area, is smaller
than ‘hie rest, and imperforate. The other four are conspicuously per-
forated for the oviducts. The left genital plate is larger than the rest,
occupies the centre of the disk, and is formed in part of the madre-
poriform tubercle, which in some specimens is very prominent and
always conspicuous. The eye-plates are small and pentagonal; they
are, as usual, placed opposite the terminations of the avenues, and are
perforate at their lower parts, but still at some little distance from their
margins, by the eye-holes, which in this species are large and conspi-
euous. [In Plate IL., fig. 7, of Desor’s Monograph of Galerites, the
eye-holes of G. (Holectypus) depressus are represented as marginal, but
an examination of them in British specimens of that species has con-
vinced me that their true position is such as I now describe in G.
hemisphericus. ‘The madreporiform body is there described as distinct
_ from the ovarian plates, and the imperforated ovarian plate as largest
in the circle, both which statements are, as I interpret the structure,
errors.| ‘The anus is placed in the lower and marginal half of the odd
interambulacral area; it is pointed above, rounded below, so that its
general outline is somewhat pyriform, or rather drop-shaped. In what
may be considered normal examples, its widest diameter is about
equal to the distance between its lower margin and the mouth; but
almost every specimen varies slightly in this respect, and the result of
an examination of more than fifty specimens has convinced me that,
further than the constant marginality of the anus, the exact proportion
its lower part bears to the ventral disk is not to be received as a specific
character. Its breadth also varies in different. individuals, in all other
respects exactly similar.

Varieties. — Variations in convexity and in - proportion of breadth to
height are very conspicuous in this species, and among a number of
specimens from any one locality very few will be found in this respect
exactly alike. ‘The other points of variation are the distance between
the anus and the mouth. and the number and regularity of the tubercles.

[ 111. vi. | B2

4 BRITISH FOSSILS.

There are three principal forms conspicuous among these varieties,
which, if separated from each other in collections, might seem specifi-

cally distinct, but between which every gradation of transition may be

found. ‘The first of these is the more or less regular sub-depressed
hemispheric form, most common, and apparently the normal one. Its
most convex state closely approaches the conical variety, which is repre-

sented in the original figure of Discoidea hemispherica. ‘This, on one

side, passes into a small very convex variety, having the anus more than

usually marginal, in which state it appears to constitute the Holectypus

devauxianus of Cotteau, with whose figures and descriptions we have
English specimens perfectly according. On the other side it becomes
more and more depressed, until we get it only gently convex on the
back. Specimens of this kind seem to have constituted the Discoidea
marginalis of M‘Coy, said to be “‘ very abundant in the inferior oolite
of Bridport,” and respecting the identity of which with the species here
described I entertain not the slightest doubt. In order to show the
variations of dimensions in this species, I give the following measure-

ments of ten Dorsetshire specimens in the collections of the Geological

Survey :—
No. Locality. Breadth. | Height. aoe ba

Inch. Inch. Inch.
1 | Stoke Knaps(@). . .| 1 OF de Og
9} dioders Gc str At) eee 07 02
3 | Crewkerne’. sae 1% 0% 0%
4| Crewkerne . . . . 1y; o 0 34
5 | Stoke: Knaps! eo. 702s xs lt om | OF
6 | North Nibley 427). "*. i 0 8¢ 0 2
7 | Castle Cary (vy) - . - 08 0% 0%
8 | Stoke Knaps(y).- . -« 0% 08 0%
9 | Shipton Gorge .. . ow oF 0%

10 | Bridport Harbour (y) . 0% O74 07% |.

Locality and Geological Position—During the examination of the
InreRior OOLITE strata in Somersetshire and Dorsetshire by the mem-
bers of the Geological Survey, this species was collected abundantly,
chiefly in the sands of the Inferior Oolite, in numerous places, associated
in most instances with Dysaster ringens and often Dysaster bicordatus.
The following is a list of the principal localities in which it was found :

Hazelbury, Crewkerne, Lyttelton Hill near Cadbury, Whatley near

Frome, Little Windsor, Loders (top beds), Stoke Knaps, Greenland,

Compton Pauncefoot (bottom beds), Pileombe, Bruton, Shipton Gorge,

BRITISH FOSSILS. 5

Burton Bradstock, and near Burton Castle (top beds), Bridport Har-
bour, Chideock Hill, Mapperton, West Swillets, Beaminster. ‘These
localities are all included in sheets 18 and 19 of the Ordnance Map of
England. The specimens were collected by Mr. Bristow and Mr.
Gapper.

Foreign Distribution.— In Normandy, m a particular bed of the
Calcaire au Polypiers, known by the name of Caillasse.” (Desor.) “In
the Inferior Oolite of the Tour-du-Pré associated with Dysaster ringens
and Diadema depressum.” (Cotteau.)

EXPLANATION OF THE PLATE,

Fig. 1. Normal form seen from above.

Fig. 2. Under view.

Fig. 3. End view, showing the anus.

Fig. 4. Profile.

Fig. 12. Extremely depressed specimen (var. 8), seen endways.

Figs. 13 and 14. Outlines of end, over and under side of extremity, conical dwarf
variety (var. y).

Fig. 5. Arrangement of ambulacral and interambulacral plates and pores on the sides.

Fig. 6. Ditto on the base.

Fig. 7. Mode of duplication of the notches of the mouth-margins; and arrangement
of the oral terminations of the avenues.

Fig. 8. Apical disk, showing the arrangement of the genital and ocular plates, and
the madreporiform tubercle.

Fig. 10. Tubercle and granules of dorsal surface highly magnified.

Fig. 11. The same from the ventral surface,

Note on allied species of Galerites found in Britain.

The only British Galerites of the section Holectypus, besides the one described above,
is the G. depressa, a species which accompanies G. hemispherica in most of the localities
cited, and which has a much wider distribution, occurring, in England, in inferior oolite,
where it appears to be most abundant, in fullers’ earth and in cornbrash. It is at once
distinguished from G'. hemispherica by the position of the anus, which is entirely ventral,
very large, extending from very near the mouth to the margin of the under surface, and
of an oblong pyriform shape, pointed at its inner end, and widest towards its marginal
termination a little beyond half its length. The dorsal surface is depressed, yet regularly
convex, the margins rounded, but having a tendency to compression, consequently the
greatest breadth of the entire body is in the diameter immediately above the margin. The
spiniferous tubercles of the dorsal surface are very small; they are very numerous near
the edge, but become fewer and more scattered, though very conspicuous and compara-
tively large, on the ventral surface, as they approach the mouth. Individuals vary greatly
in the degree of dorsal convexity. From one inch to one inch and a-half across is the
usual diameter of well-grown specimens,

Epwarp Forees.
June, 1850.

DECADE 3Fi-7. am

Geological Survep of the United Kingdom. CALERITES

( Cretaceous)

GALERITES GASTANEA Brongniart.

ae Pe ee ee ee ee
:

DRITISH. FOSSILS.

DecavE III. Puare VII.

GALERITES (GALERITES) CASTANEA.

[Genus GALERITES. Lamarcx. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinide. Family Cassidulide.) Body more or less hemispherical, always tumid ;
ambulacra simple, continuous, radiant; mouth central, inferior; anus inferior or sub-
marginal; tubercles perforate. |

[Sub-genus Galerites. Body hemispheric, sub-globose, or conical; base more or less
flattened ; tubercles irregularly arranged. |

Synonyms. Forma a. major.—Nucleolites castanea, ALEX. BRoNG-
WIART, Env. de Paris, pp. 100 and 349, pl. 9, fig. 14. Catopygus castanea,
Acassiz, Prodr. Ech., p. 18. Pyrina castanea, DesMoULINS, Tabl. Synon.
des Echin., p. 258. Galerites castanea, Acassiz, Cat. Syst. Ech., p. 7;
and Ech. Foss. de Ja Suisse, Ist part, p. 77, pl. 12, figs. 7,9. Drsor,
Monog. des Galerites, p. 23, pl. 4, figs. 12-16. AGassiz and Drsor, Cat.
Rais. des Echin. Ann. Sc. Nat., 3rd series, vol. vii., p. 149. Galerites
Rothomagensis, Acassiz, Cat. Syst., p. 7, (fide DEsor).

Forma (. minor.—Nucleolites depressa, ALEX, BRONGNIART, Env. de
Paris, p. 400, pl. 9, f.17. Catopygus depressus, AGassiz, Prodr., p. 18.
Pyrina depressa, DEsMouuins, Tab. Synon., p. 258. DxEsor, Monog. des
Galerites, p. 28. AcGassiz and Drsor, Cat. Rais. des Echin., Ann. Sc.
Nat., 3rd series, vol. vii., p. 150. Galerites castanea, Acassiz, Cat. Syst.,
p. 7 in part (fide Desor). Galerites rothomagensis, KE. StsmonpA, Echin.
Foss. Nizza, p. 51, pl. 2, figs. 8-10. Galerites levis, AGassiz, Cat. Syst.,
p- 72.2? Desor, Monog. des Galerites, p. 24, pl. 4, figs. 8-11.?

Draenosis. G. corpore depresso, ovato seu suborbiculari, lateribus ro-

tundatis ; ano postico, supra-marginali ; tuberculis omnibus sub-equalibus ;
poris ambulacralibus ad orem laxe confertis.

In the “ Geology of the Environs of Paris” there are two cretaceous
urchins from Savoy, figured under the names of Nucleolites castanea
and WNucleolites depressa, which I take to be varieties of one species of
Galerites, and to be identical with that which is here described and
figured. ‘The slight distinction in the degree of elevation of the anus
above the margin, noticed by Brongniart, was not sufficient to establish
a specific difference ; and as the smaller form was styled depressa under
the belief that it might be the Galerites depressus of Lamarck, the
specific name castanea is adopted for both varieties.

[ 111. vil. | B

2 BRITISH FOSSILS.

This view, however, is not taken by continental authors, though
originally held by Agassiz, who, in his Systematic Catalogue, regarded
the Nucleolites depressa of Brongniart as one with that author’s JV. cas-
tanea, and placed them both under the name Gralerites castanea. Des-
moulins, in his ‘ Tableaux Synonymiques,” enumerates both as
distinct, and places them in the genus Pyrina. Desor, in his Mono-

graph of the Galerites, identifies G. castanea with the Galerites rotho-

magensis of Agassiz’s Catalogue, but places in the genus Pyrina the
Nucleolites depressa of Brongniart. In the “Catalogue Raisonné des
Echinides” the authors keep the G. rothomagensis and G. castanea under
the latter name, and refer to the figures of the former and descrip-
tions of both species in E. Sismonda’s ‘* Memoirs on the Fossil Echinide
of Nice.” In that work the figures of G. rothomagensis accord excel

lently with the British species before us, and the author remarks that
the distinctions between the two are very slight indeed: ‘“‘ Non e che
per leggerissime modificazioni dei principali caratteri, che questa specie
puo staccarsi dal Galerites castanea, di cui la tutto Vabito.” Yet,
assuredly, the Italian species is much closer to the original ‘figures: of
** Nucleolites” depressa than to those of Galerites castanea. Such, in
brief, is the history of our species, which, in England however, is
not likely to be confounded with any other member of its genus, or to
be regarded as a member of any other sub-genus than that to which
we have assigned it.

The figures of the Galerites levis of Agassiz in Desor’s Monograph
have all the appearance of being representations of a variety of this
species which occurs at Warminster. M. Desor describes and figures
it from the only specimen he had met with—one in the collection of
M. Deshayes, from cretaceous strata in France. Mr. M‘Coy, in his
additions to Morris’s Catalogue, mentions both Galerites castanea and.
Galerites levis as British species.

British specimens of this species almost all belong to the small
variety, and those which I have examined and figured are of an ovate
or suborbicular form, inclining to obtusely pentagular or hexangular.
They vary much in the degree of tumidity and height as compared
with the length and breadth, being sometimes nearly convex on the
summit, at others depressed. ‘The obscure angles, when they are five,
correspond to the ambulacral areas ; when there is a sixth, it is in the
centre of the posterior or odd interambulacral space. The inter-
ambulacral areas exceed the breadth of the ambulacral by three-fifths
on the middle of the sides. ‘The sides are so rounded that their most
tumid portions are central or sub-central. The base is flattened in the

centre, rounded off at the sides, and has the mouth nearly in its —

middle. The mouth is rather small, rounded, and obscurely decago-

BRITISH FOSSILS. 3

nal. The anus is elliptical, one-third greater in vertical dimensions
than the mouth, and is placed at the hinder extremity in the lower
part of the posterior interambulacral area immediately above the
margin. It varies a little in degree of elevation in different speci-
mens. Its margins are occasionally, though rarely, slightly thickened.
The plates, both dorsal and ventral, are thickly covered with miliary
granules, among which are distributed the spiniferous tubercles, per-
forated and placed on a crenulated protuberance within an areola.
These tubercles are very little smaller on the dorsal surface than
they are on the ventral. On the centro-lateral interambulacral plates
there are from 15 to 30 tubercles. On the interambulacral areas they
fall into obscure oblique ranks of three or four. In a specimen six-
tenths of an inch in height, there are about 22 rows of plates to each
half of an interambulacral area, and about six ambulacral plates with —
as many pairs of pores to each of the former.

The apical disk is composed of five genital and five ocular plates ;
four of the former are perforated, and one, the posterior one, imper-
forated and small. The left anterior genital plate is larger than the
others, and produced to form the central madreporiform plate. The
remainder of the disk is granulated with scattered miliary tubercles.
All the ocular plates are perforated. The pairs of pores are in single
file on the back and sides ; but when they turn the margin to proceed
down the under surface to the mouth, they gradually fall into ranks of
three pair, always very oblique, and never very closely set. The spines

are unknown. Internal casts exhibit the ambulacra in prominent
relief. 2

The larger variety is found at Warminster, and is more depressed
usually than the smaller. In no essential character do they differ
from each other.

The following measurements of six specimens will show the variability
of proportions :-—

1 (a) 2 (8) 3 (6) 4 (B) 5 (6) 6 (6)
Length . . 13 oO oll 1 on 08
Br eadth ° ® 1 1b Z 07 019 013 018 0%
OF OF 07 OF

Height . A 0% 07,

Localities and Geological Position.—This Galerites is characteristic -
of the bed of chalk marl, tinged green, with scattered particles of sili-
eate of iron, which occurs, occupying a thickness frequently of two or
three feet, at the junction of the chalk marl and green sand, and which
has been described by Captain Ibbetson under the name of Cutoriric

4 : BRITISH FOSSILS.

Maru. It is a very remarkable stratum, abounding in peculiar fossils,
and containing numerous echinoderms. I have examined it and found
the small variety of Galerites castanea plentifully near the village of
Chaldon, in Dorsetshire. Mr. Morris and Captain Ibbetson have col-
lected it in a corresponding geological position in several localities of the
same county. Both larger and smaller varieties occur near Warminster.

Foreign Distribution—In Savoy and in Normandy, apparently
always in the same geological horizon as in England.

DESCRIPTION OF THE PLATE.

Figs. 1, 2, 38,4. Various positions of a perfect example from Dorsetshire of the tumid
form of var. Minor.

Fig. 5, Internal cast.

Fig. 6. Ambulacral and interambulacral plates and their sculpture, taken from the
centre of the sides.

Fig. 7. Arrangement of the pairs of pores in the neighbourhood of the mouth.

Fig. 8. Diagram showing the relative position of the pores and avenues.

Fig. 9. Anus. —

Fig. 10. Primary tubercle and granules, highly magnified.

EDWARD ForBEs.
June, 1850.

7

at DECADE 3. PL.8-

GALIERITE §

(Cretaceous)

OX

O59?

CALERITES*AtRoCcaATmnT Ss loi

BRITISH FOSSILS.

DecapeE II]. Prate VIII.

ee

GALERITES (GALERITES) ALBOGALERUS.

[Genus GALERITES. Lamarcx. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinidex. Family Cassidulide.) Body more or less hemispherical, always tumid ;
ambulacra simple, continuous, radiant; mouth central, inferior; anus inferior or sub-
marginal; tubercles perforate. ]

[Sub-genus Galerites. Body hemispheric, sub-globose, or conical; base more or less
flattened ; tubercles irregularly arranged.

Synonyms. Conulus albogalerus, Leskr, ap Klein, p. 162, pl. 18,
figs. A, B. Echinus albo-galerus, GMELIN, p. 3181, No. 46. Galerites
albo-galerus, LAMARCK, vol. iii., p. 306; Drsmoutins, Tab. Syn. p. 248 ;
GotprFuss, Pet. Genn., p. 127, pl. 40, fig. 19; Sroxrs, Geol. Trans., 2nd
series, vol. ii., p. 406, pl. 45, figs. 14, 15; Dxsor, Monog. des Galerites,
p. 4, pl. 1, figs. 4-11, and 13, fig. 7; Agassiz and Drsor, Cat. Rais. des
Kchin., Ann. des Sciences Nat., 3rd ser., vol. vii., p. 148. Conulus albo-
galerus, Fuemina, Brit. An. p.481; Mawnrertx, Geol. Sussex, pl. 17, figs. 8,
20; Parkinson, Org. Rem., vol. iii., pl. 2, figs. 10, 11. Hehinoneus
albo-galerus, Dr BuatnvitiE, Zooph., p. 194. Disecoidea albogalera.
Aaassiz, Prod., p. 186; Bronn, Lethea Geog., p. 614, pl. 29, fig. 18
a,b. Galerites cretosus, MANTELL, Medals, vol. i., p. 384.

Forma a. Normalis. (The figures quoted above represent the typical
form.)

Forma 8. Tumidior. Galerites conica, AGAss1z; DEsor, Monog. des

Galerites, p. 16, pl. 1, figs. 12-19. Conulus albogalerus, MANTELL, Geol.
Sussex, pl. 17, figs. 8 and 20.

Draenosis. G. corpore alto, conoideo, ad basin angulato tuberculis
infra majoribus ; ano elliptico, infero, submarginali, margine incrassato sub-
rostrato; ports ambulacralibus ad orem compacte confertis.

The general form of the Galerites albogalerus is that of a sugar-loaf,
pyramidal or conical, with a flattened base ; varying from a tall pyramid
with very steep sides to a short one with swelling sides, always com-
pressed and subangular at the junction of the sides or dorsal surface
with the base or ventral surface. Above, it is divided into ten areas
by the straight radiating avenues of pores; the interambulacral areas

[ri1. vill. | B

Z BRITISH FOSSILS.

a little below the centre of the sides are equal to from three to three
and a-half of the ambulacral areas. In a specimen an inch and four-
twelfths high, about 15 plates constituted each half of a dorsal mter-
ambulacral area, and about 75 each half of an ambulacral. ~The
greater number of interambulacral plates are nearly equal in vertical
diameter, but widen out in transverse dimensions from apex to base.
The ambulacrals are minute, and often cuneiform, and are separated
from each other not unfrequently by small accessory plates. Rather
more than four of the former are equal to the length of the inter-
ambulacral plate opposite them. All the dorsal plates are covered with
very minute miliary granules, which give but very slight or scarcely
any roughness to the surface when it is denuded of spines. These
are interspersed with small spiniferous tubercles, numerous, scattered,
but presenting an hour-glass like arrangement on each interambulacral
plate, one or two on each ambulacral. Each of these spiniferous
tubercles is perforated on the apex, and placed on a mammilliform
boss with a crenulated summit, and surrounded by a smooth areola.

The base is flat. Its ambulacral and interambulacral areas are
studded with numerous spiniferous tubercles larger than those of the
dorsal surface; in the former they form oblique rows of fours or at
most five, across the whole of each ambulacral space near the margin,
and diminishing in number towards the mouth; in the latter they are
thickly crowded towards the margin, and ranged towards the mouth in
oblong transverse groups, interrupted by raised granulated wavy
spaces, which mark the lines of junction of the plates, and forming an
arachnoid arrangement of irregular rings on the base, of which the
mouth is the centre. The base is elongated posteally, thickened and
subrostrated for the anus, which is large and broadly elliptical in a
longitudinal direction. Its margins are raised and thick. ‘The size of
the vent usually exceeds that of the mouth by one-third. The mouth
appears round, but is obscurely decagonal, being gently notched at its
margins opposite the avenues of pores. It is inflexed opposite each
area, the inflections opposite the interambulacral areas being deeper and
' semicircular. The pairs of pores are small, ranged in single file down
the dorsal surface, falling into series of three pairs on the base soon after
passing the margin. ‘The series become more and more oblique until, at
the tenth or eleventh from the base, they are directly under each other,
and consequently give considerable breadth to the avenues. Three
lines drawn up each avenue in the inner half of its basal course will in-
tersect one of the pair of pores of each series. |

The miliary tubercles of the dorsal plates bear very minute and
short tubercular smooth spines, each standing apart from its neighbours.
The spines on the tubercles of the upper surface I have not seen.

a BRITISH FOSSILS. ; | 3

Those of the lower surface are two-tenths of an inch in length, slender,
tapering, smooth, longitudinally ridged with about: eight ridges and
enlarged at the base, where they are surrounded by a crenulated collar.
Curious club-tipped pedicellaria-like bodies occur among them, which
may represent the spines of the miliary tubercles described as ore
on the dorsal surface.

Mr. Bowerbank has communicated the result of a microscopic exami-
nation of the spines of Galerites in his possession. He finds the small
dorsal spines of Galerites albogalerus to differ from those of subrotundus
in being thickened at the base and set on the tubercles as it were

_ sessile, instead of being shortly pedunculated, as they are in the latter

species. ‘The minute moniliform spines of G. albogalerus are +ys of an
inch in length and of equal diameter. Three were measured, and all
were as nearly as possible of the same size and proportions. ‘They were
all perfectly smooth.

The apex of the body is the highest point of the back. The apical
disk is formed of five genital and five ocular plates. Four of the former
are perforated for the oviducts in their lower halves; one of the per-
forated plates is greatly enlarged above, to form the centre of the disk,
where it is wrinkled and punctured, constituting the madreporiform
plate. The fifth posterior and odd genital plate is very small, triangular,
and imperforate. The perforations of all are nearly marginal.

The existence of a dental system in Galerites was made known by
Mr. Charles Stokes, who communicated his discovery to the Geological
Society. A second specimen with teeth adorns the collection of Mr.

_ Bowerbank, and in it the dental “lantern” is sufficiently protruded to

enable us to determine the form and structure of its principal elements.

. The teeth are smooth, white, lanceolate, triangular, each consisting of a

concave lamina terminating below in the dental point, and strengthened
on its back by a prominent rounded ridge. In the “ Catalogue Raisonné
des Echinides,’ the authors have by an oversight attributed as a
character to the Cassidulide, the absence of a masticatory apparatus.
It is probable that all the members of that family had a dental system
similar to that of Galerites. The absence of traces of it in fossil speci-
mens must be accounted for in the same way in which we know the
absence of the dental lantern in dead specimens of existing Hchini to
have been caused, viz., by the decay of the internal parts and the dis-
articulation of the segments of the masticatory apparatus.

The following table of the relative dimensions of nine specimens,
among those in the collection of the Geological Survey, will give some
idea of the variable proportions in this species.

4. BRITISH FOSSILS.

|
Lat. Diameter
No. of | Length at | Breadth at Height at a Fourth
Specimen.| Base. Base. * | of the Height
from the Apex..

Inch. Inch. Inch. Inch.
1 lt lq5 li O75
2 1% 1} 1p Ot
3 lt li ly 075
4 1g 1p li 0%
5 12s ope ee 08
6 1% 1g 1% 0%
7 14 Tee eee 08
8 1% 1% 1% 048
9 lis ly 0% 0%

Affinities—In the valuable Monograph of Galerites by M. Desor,
there are eleven species of the genus (in its most restricted sense)
enumerated, all of which would rank, according to the views we have
adopted in these memoirs, as members of the sub-genus Galerites. Nine,
if not the whole eleven of Desor’s species are found in British cretaceous
strata. After a careful consideration of figures, specimens, and citations,
IT have come to the conclusion that the whole eleven may be reduced
to only four true species, one of them the Galerites before us, the other
three very nearly allied forms. The species of the sub-genus Galerites
which I recognize as truly entitled to that rank are the followmg :—

Ist. G. albogalerus ; first so named by Kleim on account of its fancied
resemblance to the white caps worn by the priests of Jupiter, the com-
mon form here figured and described in detail, previously noticed by
many old writers and sometimes rudely figured ; it was adopted into strict
scientific nomenclature by Gmelin in the thirteenth edition of the
‘Systema Nature.’ There was never any mistake about the typical
form of this species, and though the generic name has been frequently
changed, the old and appropriate specific denomination has been held
sacred and should be kept. I regret, therefore, that Dr. Mantell should
have recently applied to it a new epithet—the word cretaceus, applicable
to all the species of the sub-genus Galerites, in his excellent popular
manual of Paleontology, the ‘‘ Medals of Creation.”

The fourth species in M. Desor’s Monograph, is one of the com-
monest varieties of albogalerus, elevated to a species by Agassiz, under
the name of Galerites conica. Every gradation of outline between it
and the typical form (which is the more conical of the two) is to be met
with abundantly in the English chalk. In describing it, M. Desor has
carefully contrasted its characters with G. vulgaris; the distinctions he

BRITISH FOSSILS. 5

enumerates are those which separate the latter from albogalerus. He
remarks, that possibly the conica may prove to be the male of vulgaris.
For stratigraphical reasons, I do not think this can be the case, but were
it so, then albogalerus as a whole must be taken as the male of vulgaris.
It is more probable that the pyramidal and tumid forms of albogalerus,
considered distinct by Agassiz and Desor, under the names albogalerus
and conica, may be respectively male and female; but even this hypo-
thesis I abstain from proposing, when I see the complete and gradual
transition which specimens exhibit between the two extremes of form.

2. G. abbreviatus.—Certain old figures in the works of Klein, Leske,
and others gave origin to the establishment of a Galerites under the
names of abbreviatus (Lamarck), truncatus (Defrance), and (in part)
vulgaris. ‘The synonymy of this type is fully given by M. Desor, with
excellent figures of one of its ordinary varieties (Monog. des Galerites,
tab. 3, figs. 9-17). It is the Galerites vulgaris of Goldfuss and of
Bronn, and another variety is the Galerites abbreviatus of the former
author, which in the “ Catalogue Raisonné,” M. Desor elevates to dis-
tinct rank as G. oblongus. It is the Conulus vulgaris figured by
Parkinson, and probably the species enumerated under that term by
Mantell. Varieties of it are figured under the names of Galerites
vulgaris « and 8, by Woodward, in his “‘ Geology of Norfolk,” plate 5,
figs. 2 and 3, as has been proved to me from specimens by my friend
Mr. 8. P. Woodward, of the British Museum, who has further indicated
to me its identity with the Galerites angulosa of Desor (Monog. des Gal.,
plate 4, figs. 5-7), and Carotomus hemisphericus of Desor (Monog.
p. 37, plate 5, figs. 14, 15), both founded on well-known English
specimens in the collection of the Marquis of Northampton, and of
which I have examined exact parallels in the museum of Mr. Bower-
bank, the former, indeed, being identical with Galerites vulgaris of
the ‘‘ Geology of Norfolk,” and the latter with var. 6 of the same work.
Moreover, I have scarcely a doubt that the Galerites pyramidalis of
the “* Monograph des Galerites,” plate 1, figs. 1 to 3, founded on a single
flint-cast—a most insufficient ground in this genus upon which to con-
stitute a distinct species,—-is also Galerites abbreviatus.

The humber of spurious species which have thus been constituted out
of one, is scarcely to be wondered at, when the extreme variability of its
shape is considered. Of the specimens I have seen with the shell pre-
served no two are alike, and certainly the extremely depressed Carotomus
hemisphericus might very fairly be regarded as at least specifically
distinct, were it not that characters sounder than mere outline, mark it as
the same, and that all intermediate gradations of convexity may easily
be shown. From Galerites albogalerus this species is truly distinguished

6 BRITISH FOSSILS.

by the constant rotundity of its basal margin, which is tumidly rounded,
instead of being subangularly compressed. ‘The ambulacral areas are
usually prominent, often so much so as to give a strong angularity to the
contour, and always narrower in proportion to the interambulacrals than
in the other species. The anus is inferior, strongly and tumidly promi-

‘nent and marginated, and always either rownd or broader than long, a _

character never present in its congeners. The whole surface above and.

below is rough with granulations, interspersed with the primary tubercles,
which are nearly equal on the ventral and dorsal surfaces. The miliary
granulation is quite as strong above as below, and strikingly contrasts
with the apparent smoothness of the surface which distinguishes albo-
galerus and subrotundus. The margins of the mouth are usually
tumid, and the avenues of pores when advancing to it, do not become so
' closely ranked as in the species just named. Galerites abbreviatus
appears to be characteristic of the upper chalk. |

3. G. subrotundus.—Although this name was given by Agassiz to a
single English specimen, and previously by Mantell to a questionable
cast, I prefer retaining it to using that of vulgaris, adopted, after
Lamarck, by Agassiz and Desor, for what I regard as perhaps the more
ordinary form of the same species. I reject the latter name, since under
it so many good figures of the last species mentioned have been pub-
lished, and adopt subrotundus, since one of its forms has been ex-
cellently figured under that name by Desor, and since it has not
been applied to any other species. It is a common English Galerite,
and apparently is chiefly confined to a lower geological horizon
than that of the two preceding species, being chiefly character-
istic of the hard or lower chalk. In form, it varies from a depressed

spheroid with a truncated base to nearly globular; the anus is always —

vertically elliptical, not rostrated nor tumid, and is placed on, or in
some occasion3l specimens, above the margin. ‘The mouth is central.
The margins of the sides are always more or less rounded. The
spiniferous tubercles of the base are conspicuously larger than those of

the dorsal surface, but all are smaller and more numerous than those ©

of albogalerus. ‘The spines of the lower surface are smaller and
different. The pairs of pores fall into close ranks near the mouth, but
are more oblique, and the series are not so directly under each other as
in albogalerus. The Galerites giobulus of Desor, founded on a single
white-chalk English specimen, is a not rare but exceptional dwarf variety,
and Globator nucleus of Agassiz is something too like an abnormality
of this species. Galerites Leshii {Desor), is another variety.

A. Galerites castanea, with which I unite Pyrina depressa and Galerites
levis, possibly also Galerites Orbignyana (founded on a single specimen
from Touraine) may fall in here. But of this fourth species I have fully
treated in the account of Galerites castanea. :

a

See toe

nee

BRITISH FOSSILS. 7

I cannot reconcile the Galerites globosus and Galerites elongatus of
F. A. Rémer (‘“ Versteinerungen des Norddeutchen Kreidegebirges,”
Pl. VL, figs. 14 and 15) with any ofthe above. The figures are, however,
very bad, and it is not improbable that the former may prove identical
with the nucleus variety of subrotundus, and the latter with some form
of abbreviatus.

A fifth species of true Galerites, but one not hitherto found in Britain,
is the G. subspheroidalis of D’Archiac, deseribed and figured in that
geologist’s excellent account of the fossils of the Tourtia. It is allied to
G. subrotundus, but is perfectly distinct, and should be sought for im the

upper beds of the English lower green-sand, where many Tourtia fossils

occur.

Localities and Geological Position.—This species is found distributed
throughout the white chalk of the English cretaceous districts. It is
very abundant in the south. Very fine specimens are found in Kent, as
at Gravesend, &c. Examples with spines are contained in the Museum

- of the Geological Survey, and in Mr. Bowerbank’s collection. Specimens

showing the teeth are in the collections of Mr. Stokes and Mr. Bowerbank.
Some interesting forms have been presented to the Survey by Mr.

Wetherell.
Foreign Localities.—White chalk of France, Germany, and Belgium,

apparently not universally diffused through the spread of this formation.

DESCRIPTION OF THE PLATE.

Fig. 1. Profile of the most common variety.

Fig. 2. The same seen from below.

Fig. 3. Outline (lateral view) of an extremely pyramidal specimen.

Fig. 4. Outline (lateral view) of an extremely depressed and tumid variety.

Fig. 5. Ambulacral and interambulacral plates, pores, and tubercles, taken from the
centre of the sides.

Fig. 6. Arrangement of pores and tubercles in the neighbourhood of the mouth.

Fig. 7. Spiniferous tubercles and miliary granules taken from the base.

Fig. 8. Greatly magnified figures of the small tubercular spines of the dorso-lateral
plates.

Fig. 9. a. One of the spines of the lower surface highly magnified. c. Its section.
d. Pedicellaria-like body, intermixed with the spines. 6. Portion of spine of Galerites
subrotundus for comparison.

Fig. 10. Masticatory apparatus, natural size. a. The same seen from one side, highly
magnified. 6. One of the teeth seen in profile.

Fig. 11. Diagram of the supports of the masticatory apparatus around the inner rim
of the mouth.

Fig.-12, Apical disk; genital and ocular plates.

June, 1850, - ‘

BRITISH FOSSILS.

Subgenera and Species of Galerites found in Britain, ee

Genus. GALERITES.

Subgenus I. GALERITES (the British species are all upper-cretaceous).
1. albogalerus, Klein.
2. abbreviata, Lamarck.
3. subrotunda, Mantell.
4. castanea, Brongniart. .

Subgenus II. Caroromus.

1. rostrata, Agassiz (upper green sand).
Subgenus ITI. Discorpxa (all the British species are cretaceous).
1. cylindrica, Lamarck, | ;
2. favrina, Desor.
3. subuculus, Leske.
-4, Dizont, Forbes.

Subgenus IV. Hoxectypvs (all the British species are oolitic).

1. depressa, Leske.
2. hemispherica, Agassiz.

Epwarp Forses, —

ae OS ne Bs .
ae,
heh

Ps
Si

DECADE. S22.
Geological Surven of the United Kingdom.

(Oolitic)

orto batsRaned

hone ey ow <
S@ac%eg

DYSASTER RINGENS

AGUSTZ.

VAR. BUDESII

,

BRITISH FOSSILS.

DecabE III. Prats IX.

DYSASTER RINGENS.

[Genus DYSASTER. Acassiz. (Sub-kingdom Radiata. Class Echinodermata. Order
Echinide. Family Cassidulide.) Body sub-discoidal; ambulacra simple, continuous,
radiant; the posterior lateral pair separated from the rest, and converging to form a sum-
mit distinct from that formed at the genital disk by the two antero-lateral and the
anterior one; mouth sub-central, inferior ; anus at the hinder extremity ; tubercles perfo-
rate.]

Synonyms. Dysaster ringens, Acass1z, Ech. Foss. de la Suisse, 1st part,
p. 5, t. 1, figs. 7-11 (18389); Cat. Syst., p.3; Desor, Monog. des Dysaster,
p. 24, pl. 1, figs. 13-17 ; Correav, Etudes sur les Echin. Foss., p. 46, pl. 2,
figs. 10-13 ; Acassrz and Drsor, Cat. Rais. des Echin; Ann. des Sc. Nat.,
ard series, vol. viii., p. 33. Collyrites ringens, DESMoULINS, 3rd Mem.
sur les Echin., p. 368. Dysaster Fudesit, Acassiz, Cat. Syst., p. 3;
Dersor, Monog. des Dysaster, p. 23, pl. 1, figs. 5-12. Dysaster subringens,
M‘Coy, Annals Nat. Hist., 2nd series, vol. ii., p. 415 (1848).

Diaenosis. D. testa depressé orbiculart, seu subpentagonali, lateribus
tumidis, dorso convexiusculo, vertice plerumque centrali; ambulaecris pos-
tero-lateralibus supra anum convergentibus ; ano in sulco terminal ; ventro
concavo, areis interambulacralibus tumidis, area postica gibbé, ore subcen-
tral. :

The curious genus to which the fossil before us belongs, although of
very late constitution, having been first founded by Agassiz in 1834,
has scarcely as yet settled down into a decided position among sea-

urchins. The species most anciently known were styled Spatangites by

Leske, assigned to Ananchytes by Lamarck, and Nucleolites by Munster.
Since Dysaster was constituted for their reception, it was first
placed among the “ Spatangoides” by Agassiz, referred to the “ Cly-
peastroides” by Desor, and back again to the former family by Agassiz
and Desor jointly. Very recently, M. Gustave Cotteau, in his ex-

- cellent work on the fossil Echinide of the department de L’Yonne, has

inclined to regard them as members of the Cassidulide. After an
earnest consideration of their structural relations, I do not hesitate to
place them in the last-named family, in which they have distinct and
close affinity with Hyboclypus and Galerites. ‘The form of the ambu-
lacra, combined with the structure of the mouth, is sufficient to warrant

~ guch a conclusion. In the foreign Dysaster semiglobus (Nucleolites

[xr ix.] B

2 BRITISH FOSSILS.

semiglobus of Munster) we see a species which is truly intermediate
between such a Galerites as G. castaneus and the more typical forms -
Dysaster.

British specimens of this Dysaster vary in outline from nearly com-
pletely circular to subpentagonal, with even an approach to oblong ;
every gradation between the two extremes of form is common. The

dorsal surface is very uniformly and gently convex, though varying con-

siderably in altitude. ‘The highest point of the back is almost always a
little behind the centre ; very rarely a specimen is met with having it
still further back. The sides are tumid, and in the subpentagonal
specimens, slightly and very obtusely angulated by the prominence of the
interambulacral spaces. ‘The ventral surface is concave in the region of
the mouth, very convex, and almost nodulose in the interambulacral
spaces ; the ambulacral areas being depressed. ‘The odd or anal inter-
ambulacral area is peculiarly prominent and gibbous. Its extremity is
squared by the inferior terminations of two ridges which bound the
conical groove, in the upper part of which, nearly, but not quite on a
level with the dorsal surface of the body, is lodged the anus.

The three anterior ambulacra converge nearly in the centre of the
back. The antero-laterals are separated on each side from the anterior
ambulacrum by a perforated genital plate; that of the left side is granu-
lated in its upper part, being the madreporiform plate. Behind the summits
of the antero-lateral ambulacra, which curve gently forwards before they
terminate, are the other two genital holes. ‘The eye-holes are very
small, but distinctly termimate the three anterior ‘ambulacra; the other
two seem to be removed from the disk to the terminations of the
postero-lateral ambulacra, but of this I have not clearly satisfied
myself.

The ambulacra are all complete, running from the mouth to their
dorsal terminations ; on the back they are on a level with the inter-
ambulacral plates. The number of ambulacral plates exceeds that of
the interambulacrals by four or five times. ‘The three anterior ambu-
lacra are narrower than the two posterior, which are often nearly but
not quite twice as broad as the former; the proportionate width, how-
ever, as I have satisfied myself by measurements, is not constant. The
narrowest ambulacrum towards its summit is the anterior one, but it
widens out lower down. Each pair of ambulacral plates is perforated
at its outer side by a pair of pores. Near the mouth the ambulacra
widen, and the pairs of pores are ranked in about three oblique series of
three pair in each, but their relations to the plates there are obscure.

All the plates, whether ambulacral or interambulacral, are minutely ©

granulated, and among the granules are interspersed very small spinife-
rous tubercles with ae and punctated summits; but whether the
bosses on which they stand are crenulated I have not tes able to make

BRITISH FOSSILS. 3

out satisfactorily in this species. ‘The tubercles are most numerous
below. The spines are unknown.

The mouth and anus are of about equal dimensions, being each in
diameter rather less than one-eighth of the length of the shell. The
position of the mouth is subcentral, but sometimes the eccentricity 1s
considerable. It is very obscurely decagonal, but seems to the eye as if
round. No traces of dental armature have as yet been discovered.

Varieties—The specimens we have figured accord best with the
representations of the Dysaster Eudesii of Agassiz, as figured in the
Monograph by Desor. Many English examples are, however, suffi-
ciently flattened out to represent very perfectly the rzngens of that
work. In the description of the species there given it is implied that
the latter differs from the former importantly in the circumstance of its
anterior ambulacra being narrower than the posterior ;_ the figures of D.
Eudesii, however, represent the ambulacra as presenting similar relative
proportions with those of ringens. M. Cotteau refers this Dysaster of
the “oolite ferrugineuse”’ of the Tour-du-Pré to the ringens. His
figure would serve as a good representation of some of our English
specimens. He remarks that he and M. Moreau have collected in
a single locality a suite of examples of D. ringens presenting various
degrees of tumidity and more or less circularity of outline, and among
which were all the gradations conducting to D. Hudesi “qui ne serait
alors qu’une varieté plus petite et plus allongée du Dysaster ringens.”
The experience of the Survey collectors leads me to the same con-
clusion.

Professor M‘Coy, in his memoir ‘‘On some new Mesozoic Radiata,”
in the “ Annals of Natural History” for December, 1848, has enumerated
D. Eudesii as a British species from the inferior oolite of Dundry and
Bridport. At the same time he describes two new species of Dysaster
under the names of D. symmetricus and D. subringens; the former “not
uncommon in the inferior oolite of Bridport,” the latter “not uncommon
in the inferior oolite of Dundry and Leckhampton.” After a careful
perusal of his descriptions, I am obliged to surmise that the latter
species (an opinion supported, after comparison with the original speci-
men, by Mr. Salter), is a variety of the species now described. I can
find no character in his descriptions which would warrant their specific
separation ; and, as in the case of his subringens, he compares it with
ringens and Hudesii, distinguishing it from the former “ by its greater
gibbosity and the less prominence of the ridges on the under side,” and
from the latter ‘‘ by the disproportionate narrowness of the three anterior
ambulacra as in the D. ringens ;’” characters which vary in every speci-
men, I do not hesitate to include it among the synonyms of ringens. In
the same paper he mentions Dysaster avellana, of Agassiz, as also from
the inferior oolite of Bridport; I cannot satisfy myself, after examining

4 BRITISH FOSSILS.

Desor’s figures and descriptions, that the species in question is distinct
from D. bicordatus ; and certainly, industriously as the Survey collectors
have ransacked the inferior oolites of Dersetshire, I have never received
any other species of Dysaster from thence, except Dysaster ringens, as
here described, and Dysaster bicordatus, a very different form, of which
Mr. M‘Coy’s D. symmetricus is an oval variety.

The following table of the dimensions of eight specimens, in inches

and twelfths, from the Bridport oolite, will show the variable propor-
tions of this species.

A B | C D. E F G H
Length . Im | ln | On | OF | 0 % | Of | O8 | Of
Breadth . .| 1 1a | OF | OF | Of | OF o12 | 09
Thickness . | 05 os OF c= 0% 0% 0% 0%

Localities and Geological Position —This species has been collected
abundantly by Mr. Bristow and Mr. Gapper during the examination in
the course of the Geological Survey of the Inrerror oorrre of Somer-
setshire and Dorsetshire. It appears to occur chiefly in the sands of
that formation, and is very generally the companion of Galerites (Holec-
typus) hemispherica. Among the localities from whence I have
examined specimens are the following: Lyttelton-hill, near South Cad-
bury ; between Sherborne and Yeovil; Little Windsor ; Stoke Knaps.
Greenland (in the ferruginous beds), Loders; Whatley; Smokeham ;
Honeycombe ; Bradford Abbas ; Beaminster ; Shipton Gorge, where it is
accompanied by Dysaster bicordatus; Burton Bradstock ; Burton Cliffs

(top beds) ; near Bridport Harbour ; Chideock-hill ; Mapperton ; West -

Swillets. The places mentioned are included in sheets 18 and 19 of
the Ordnance Survey Map of England.

Foreign Distribution.—In the ‘* Marnes Vesuliennes” of the Jura
(Agassiz); in the ferruginous oolite of Normandy (Deslonchamps) ; in
the ferruginous oolite of the Tour-du-Pré (Cotteau).

sj ere OF THE PLATE.

Fig. 1. View of body seen from above.

Fig. 2, Underside of same specimen.

Fig 32. Terminal view.

Fig. 4. Terminal view of a wider specimen.

Figs. 5 and 6. Profile of variations in proportions of specimens.

Fig. 7. Diagram of structure of test, the plates of the disk and those above the anus not
made out.

8. Oral terminations of the ambulacra, showing the triplication of the pores.

9. Relative proportions of ambulacral and interambulacral plates, taken from the sides.

10. Tubercles and granules of surface.

11. Genital disk, terminations of anterior ambulacra, and madreporiform plate.

June, 1850. : : EDWARD FoRBEs.

Aa

DECADE 3. PL.10.

Geological Surbep of the United Kingdom. MICRASTIER

(Cretaceous)

aa!
ar
COC
Gots

Ao

uc

coon &
BGC
CRSyrc

(ore
Chere

MICRASTER coR-ANGUINUM _Gmelin.

BRITISH FOSSILS.

Decape II]. Puate X.

os

MICRASTER COR-ANGUINUM.

[Genus MICRASTER. Acassiz, (Sub-kingdom Radiata. Class Echinodermata. Order
Echinide. Family Spatangacee.) Body cordate, tumid; dorsal ambulacra narrowly
petaloid, not circumscribed by a peripetal band ; dorsal surface studded with uniform small
tubercles, no large primaries; anus terminal, supra-marginal; caudal (infra-anal) ex-
tremity circumscribed by a band. ]

Diacnosis. M. ambitu cordato, dorso convexo, postice arcuato ; am-
bulaeris dorsalibus impressis, sulcis porarum terminalium vix decrescentibus ;
assulis arearum ambulacralium dorsalium tumidis, subtuberculatis.

Forma a. Normalis, regulariter cordatus, dorso vertice subcentrali ;
genis tumidis. Spatangus cor-anguinum a. anglicum, LresKkE, ap. Klein,
p. 28, tab. 23, A, B. Hchinus cor-anguinum, GMELIN, 3195. Spatangus
cor-anguinum and punctatus. Ananchytes spatangus and semiglobosus, La-
MARCK, An. sans Vert. iii, pp. 26 and 32. Spatangus cor-anguinum,
ALEx. BroneniarT, Desc. Geol. des Env. de Paris, pl. 4, fig. 11. Spa-
tangus cor-marinum, ParKinson, Org. Rem. iii., pl. 3, fig. 11. Spatangus
cor-anguinum, Goupruss, Pet. Germ., pl. 48, fig. 6; and Spatangus cor-
testudinarium, ibid., pl. 48, fig. 5. Micraster cor-anguinum, Acassiz and
Desor, Cat. Rais., in Ann. des Sc. Nat., 3rd series, tome viii., p. 23.
Micraster cor-testudinarium, Bronn, Lethea, pl. 29, fig. 23.

Forma 8. ostratus, regulariter cordatus, dorso carinato, vertice in
area anali, genis tumidis. Ananchytes cordata, LAMARCK, An. sans
Vert. ili. Spatangus rostratus, ManTtEeLL, Geol. Suss., pl. 17, figs. 10,
12; Woopwarp, Geol. Norf., pl. 5, fig. 7. MWicraster cordatus, AGASSIZ,
Cat. Syst., 2; and Cat. Rais. des Ech., p. 23.

Forma y. Gibbus, late cordatus, dorso vertice centrali, postice an-
ticeque declivente, genis compressis.

Var. a. pyramidata. Spatangus gibbus, LaMARcK, Anim. sans Vert. iii.,
fig. in Ench. Meth., pl. 156, figs. 4-6. Micraster gibbus, AcAssiz and
Desor, Cat. Rais. des Echin. Ann. des Se. Nat., 3rd ser., tome viil., p. 24;
Fores, in Dixon’s Sussex, p, 342, pl. 24, fig. 314.

Witt: x. | B

2 BRITISH FOSSILS.

Var. b. tumidior. Spatangus gibbus, Goupruss, Pet. Germ., p. 156,
pl. 48, fig. 4. Spatangus comanguinum, Woovwarp, Geol. Norf., pl. 5,
fir. 8. Micraster gibbus, Acassiz, Cat. Syst., p. 2; E. Sismonpa, Mem.
Ech. Foss. Nizza, p. 23. Micraster brevis, Drsor, Cat. Rais. des Echin.
Ann. des Se. Nat., 3rd ser., tom. viii., p. 24.

The first illustration of the genus Micrasrer selected for these
Decades is one of our commonest cretaceous Echinide. It is chosen
partly because the perfection and abundance of specimens permit of its
structure being described and delineated more in detail than that of any
of its congeners, and partly since, common as it is, nevertheless, like
most common fossils, it requires a much more critical examination than
it has yet undergone.

It has been figured and described, according to their fashion, by many

of the older writers on fossils. Llhwyd, Hook, Breyn, Schlotheim,
Walch, Morton, Klein, Davila, Van Phelsum, and Leske have severally
represented and commented upon it. Very variable in its features, un-
less we have many specimens before us, we can scarcely put two or three
examples together which are closely alike in proportions. This capacity
for variation has caused many spurious species to be constructed out
of one. , :
It is the type of the genus Micraster of Agassiz. That genus is dis-
tinguished among the other Spatangacee with petaloid ambulacra, from
Spatangus and its allies, by its surface being covered with secondary
tubercles only, and by its rather narrow ambulacra, not bounded by or
including a fasciole of tertiary spines; by the presence of a sub-anal
fasciole from Brissus and Amphidetus.

The outline of the body is always cordate, in most specimens nearly
as broad on the widest part as long, sometimes broader than long—
rarely much longer than broad. The greatest width of the lateral out-
line is invariably a little behind the antero-lateral ambulacral plates ;
from that point to the anal extremity it describes a regular and consi-
derable curve in all the varieties. The dorsal surface varies from an
almost conical convexity (extreme form of Spatangus gibbus, Lamarck)
to depressed, as seen in the larger variety of the typical cor-anguinum.
When very conical and compressed, then the highest part, or vertex, is
at the apex, or ovarian, disk of the shell; in the depressed form it is a
little behind this disk ; in the rostrated form it is behind this disk, nearly
in the centre of the posterior interambulacral area. ‘The anterior half
of the back varies in degree of declivity in all the forms, but is especi-
ally steep in the extreme form of gidbus, and in a not uncommon varia-
tion of rostratus. Intermediate specimens, exhibiting every degree of
tumidity of the cheeks (or swelling on each side of the odd ambulacrum)
are common. As a general rule, the cheeks are tumid. The posterior half

BRITISH FOSSILS. 3

of the back varies greatly in declivity in the several varieties ; the posterior
interambulacral space declining in one set of forms, becoming elevated
in another; the former being the gidbus of Lamarck and the variety
ficured under the same name by Goldfuss, the latter being the rostratus
of Mantell, cordatus of Lamarck. But whether declining or elevated,
the outline of the posterior interambulacral space is always an arcuated
curve. According to its elevation, so is the altitude of the anus on the
truncated posterior extremity. ‘This aperture is circular, occupying a
depression bounded by a narrow and defined circle of smooth-edged
plates. The surface below it is flattened or slightly hollowed out, the
bounds of the depression corresponding to two terminal bosses or caudal
projections, which in the living animal doubtless bore two projecting
tufts of long spines. ‘These caudal projections are included within the
sub-anal circumscribed space; the circumscription (which in specimens
of this species is not always conspicuously manifest) is transversely ob-
long and inclined to quadrate. ‘The ventral surface is slightly tumid,
but sometimes nearly flat centrally. The mouth is placed very near the
anterior extremity, at the inferior termination of the deeply impressed
anterior ambulacrum. It varies slightly in position in different speci-
mens. Its projecting lip is strong and thickened, and varies in degree
of projection.

The dorsal ambulacra, or rather stellate portions of them, are through
a great part of the length of them parallel-sided, not contracting much
towards their lower extremities, so that their form is oblong-lanceolate,
and but slightly petaloid. They are all, throughout the greater part of
their length, placed in depressions of different degrees of depth in dif-
ferent examples; sometimes very shallow, and the ambulacra almost
on a level with the surface, especially in young specimens. The an-
terior or odd one is very variable in its degree of development, and
differs from the others—its ambulacral area simply granulated,
without tumidity of the separate plates: in many examples the grooves
connecting its pores are obsolete. The lateral ambulacra vary greatly
in length in different specimens and varieties: the antero-laterals are
always longer than the postero-laterals, sometimes considerably so.
The latter are longest in the conical forms of the species, but the
relative length of these ambulacra cannot be taken as a specific
character, nor can the number of the pairs of pores in them, seeing that
almost every specimen varies in this respect, as may be seen by com-
paring the enumeration in the table given hereafter. The lateral am-
bulacra, however, in other points exhibit excellent characters, constant
throughout all the individuals of every variety of the species. Their am-
bulacral plates are invariably tumid, rugose, and separated by a strongly
marked suture, whilst the general suture running down the centre of
the ambulacral area is deeply depressed and groove-like. The ridge

ra

4 BRITISH FOSSILS.

separating each poriferous groove is also tumid and studded with a
single row of Epa manal close-set tubercles, usually five or six m each
series.

The genital disk is composed of four developed genital plates, each
with an oviducal hole. The posteal or fifth plate is undeveloped. The
left antero-lateral is much larger than the others ; in its upper portion,
which occupies the centre of the disk, it is minutely punctated, forming
the madreporiform body. The eye-plates are all five developed and
perforated.

The whole of the dorsal and lateral plates are minutely granulated
and studded in a scattered manner with small, nearly equal spiniferous
tubercles, each consisting of a perforated tubercle placed on a crenu-
lated base, and surrounded by a smooth ring. ‘They become much
more closely set on the lower parts of the side, and are much larger on
the ventral surface of the body, and regularly arranged on the ovate,
acute post-oral spinous space, but are few on the ambulacral plates
bounding that area. The ambulacral pores radiating from the mouth
are lodged in short inconspicuous rather rugose grooves. ‘The sutures
of the plates below and near the anus are edged with minute granules
arranged In rows.

The spines are rarely seen, and have never before been represented,
nor, I believe, described. ‘They are very slender and small; not,
however, all minute, for some are as much as a quarter of an ine in
length, and were possibly longer. They are mostly arcuated near the
base, ridged along their length by about six ribs, which in some speci-
mens appear to be rugose with prickle-like projections apparently ar-
ranged spirally, thickened suddenly at their bases, where they are sur-
rounded by a strongly crenulated, ring. The habits of the animal, as
indicated by these spines, probably resembled those of the existing sea-
urchins of the genus Brissus.

Very young specimens are mostly of a more elonaaten form than is
seen, except rarely, in the adult; but there are also tumid young ones,
and it is possible that the sub-depressed and tumid forms of this species
(cor-anguinum and rostratus), both of which are common and found
together, may be male and female individuals respectively. 7

Flint-casts of the interior of this urchin are not uncommon, and
when in fine condition serve beautifully to illustrate the arrangement of
the plates. ‘The anterior and lateral interambulacral segments of the
body, although very unlike, are formed of about twelve pairs of plates
in each compartment. ‘Those of the anterior segment gradually in-
crease in dimensions as they approach the wider and lower portion of
the cheeks ; those of the lateral compartments are unsymmetrically un-
equal, and the lower or ventral ones assume irregular polygonal shapes
with increased size, in order to fill up the triangular sides of the oral

BRITISH FOSSILS. 5

surface. The odd or posterior interambulacral area has the plates con-
siderably distorted by the position of the vent. Those above it increase
eradually, and are about six or seven in number. From four to six
bound the sides and the lower margin of the vent, and three pair fill up
the sub-anal region as far below as the base of the post-oral spinous
space, which is composed of a pair of large triangular plates with
curved outer sides. ‘The number and arrangement of the interambu-
lacral plates does not seem to differ much in any of the varieties, but
the number of the ambulacrals differs in every specimen which is not
exactly similar to some other. Ina cast of the form cor-testudinarium
the number of pairs of pores in the anterior ambulacrum was (petaloid
region) 12 + (plane region) 15 ; in the antero-laterals (petaloid region)
25 + (plane region) 15; in the postero-laterals 19 + (plane region) 16
+ (ventral region) 5. In a cast of the gibbus form, the respective
numbers ranged in the same order were—

Anterior ambulacrum . . 22+ 12

Antero-lateral ditto. . . 85119

Postero-lateral ditto. .« . 30+17+4+5.

Flint-casts often show very clearly the arangement of the oviducal
pores and eyes. ‘The number of pairs of pores increases with age.

In the following table I have contrasted the dimensions and numbers
of pair of pores in the dorsal ambulacra of twelve adult specimens taken
from among all the chief varieties. It will be seen that these characters
are very variable, and nOt sufficient to warrant specific distinction.

Number | Number | Number
of Pores of Pores of Pores

Variety, : inarow | inarow | inarow
oo ee Length. | Breadth, | Height. | ineach | ineach | in the
g Collection Antero- Postero- | Anterior
urvey 7 lateral lateral Ambula-
Avenue. | Avenue. crum,
Inches. Inches. Inches.
1. y. Extreme form, “ Gib-
bus” of Lamarck * 2 ° = oe EY ae
2. y. Extreme but small
eda a 24, 24 13 43 30 22
3. y. TER ee le eh os 1 yy 2 1 5 36 34. 25
4. y. “Gibbus” of Goldfuss 14. 24 13 36 31 oe
Bi Ditta kee ek Pe 12, 12 33 25 18
6. Inter 7 and 8, nearer y . 2 24 13 31 21 19
@ unter cand y +. « 1 2 1% 29 21 20
S.\@ Dumid form . .) . 2 2 1d 27 22 20
9. a. Depressed. « = « 24 245 1% 52 28 20
mb. 2. Rostrated . 3. |. <6 2% 2% 13 34 25 18
Bee. DITO! es i oi ee 2 v) 1] tb 3l 22 22.

ne eeereeienneeenenimeneneeemnttemennranr nae nnien meine nie ne

6 BRITISH FOSSILS.

The very great variation of outline, tumidity, and consequent arrange-
ment of the ambulacra, have caused this Micraster to be split up into nu-
merous spurious species. But in the collections of the Geological Survey,
and in many private collections, especially those of Mr. Bowerbank and
Mr. Wetherell, where extensive suites of specimens are assembled, and
intermediate forms as carefully preserved as extreme ones, it becomes
very manifest that all resolve themselves into one species, sufficiently
marked by constant characters common to all the individuals. I have
grouped them under three conspicuous types—normalis, rostratus, and
gibbus ; but as the variations of each of these have been honoured by
not a few paleontologists with specific rank, I think it best to enumerate
all the forms which have been so distinguished.

A. ‘* Species” constructed out of the Normal form. —

1. Cor-anguinum, Auctorum. ‘The old figures in Leske’s edition of
Klein (tab. xxii, figs. A, B, C, D), are bad representations of the or-
dinary aspect of what is placed in collections under this name. The
figure of cor-anguinum, Goldfuss (Pet. Germ., tab. xlviii., fig. 6), is
perhaps the best representation of one of the most common varieties of
what is regarded as this species by all authors. Parkinson’s Spatangus
cor-marinum (Org. Rem., ii., pl. 8, fig. 11), represents a specimen
with deeper ambulacra than usual. The cor-anguinum of Woodward’s
“ Geology of Norfolk” is var. gibbus.

2. Spatangus cor-testudinarium. Goldfuss (tab. xlvii., fig. 5); A-
craster cor-testudinarium of Agassiz (Cat. Sy8t.); but more lately (in
the Catalogue Raisonné) considered by Agassiz and Desor as “ var.
lata” of their restricted Micraster cor-anguinum. ‘This is only a very
slight variety of the normal form, constructed out of such specimens as
have the mouth slightly further back than usual, a feature not unfre-
quently seen in depressed specimens. According to Agassiz, the name
** Spatangus anticus”’ of Defrance applies to this form.

3. Micraster arenatus of Agassiz (Cat. Syst.), since referred by
Agassiz and Desor to their variety ‘major’ of their cor-anguinum, to
which variety they refer the figure and description of ‘‘ Micraster are-
natus,” in E.Sismonda’s ‘‘ Memoria sugli Echinidi Fossili del contrado
di Nizza” (p. 28, tab. 1., fig. 2). In the plate in question, however, no
profile of this urchin is given, and the description of the elevation of
the back, would seem rather to indicate a variety of the gibbus or ros-
tratus types. I. A. Roemer, in his “ Versteinerungen des Nord-
deutschen Kreidegebirges,” identifies arenatus with ‘ rostratus.”

4. Micraster Michelini of Agassiz (in the Catalogue Raisonnée).
This is the cor-anguinum of Agassiz, in his “ Description des Echino-
dermes Fossiles de la Suisse” (tab. ii, figs. 14, 15); in which work he
identifies it with the cor-anguinum of previous authors. In his later

BRITISH FOSSILS. 7

catalogue he remarks on it—‘‘ Forme intermediaire entre le WM. cor-
anguinum et le M. acutus. Les ambulacraires sont dans des sillons
plus profonds et plus larges.”” His figure is a very good representation
of a very ordinary and normal specimen of cor-anguinum. Sismonda
has cited it also as such without, any-more than myself, seeing pecu-
liarities in it.

5. Spatangus punctatus, Lamarck. The figure (tab. xvii.* c. ) of
Leske, referred to as representing this species, is an ordinary but large
specimen of the normal form; and we are assured by Agassiz (Echin.
Suisse, i. p. 25) that his examination of Lamarck’s original specimens
convinced him that this, and

6. Ananchytes semiglobosus, Lamarck, and

7. Ananchytes spatangus, Lamarck, are all specimens of cor-anguinum.
The true structure of Ananchytes, as contrasted with Spatangus and
Micraster, was not understood by Lamarck, whose examination of the
Echinide generally is extremely superficial.

8. Spatangus acutus, Deshayes (Coq. Caract. des Terr., tab. xi., figs.
5 and 6), is regarded by Agassiz and Desor as a distinct species.
Judging from the figure, it appears to be a specimen of the normal
- form of cor-anguinum, in which the caudal extremity is slightly more
produced than usual, a variation not uncommon.

B. ‘* Species” constructed out of the Rostrated form.

9. Ananchytes cordatus, Lamarck. Micraster cordatus, Agassiz and

Desor. Regarded as distinct also by E. Sismondi. Identical with
this is |

Reet: Spatangus rostratus, Mantell; and, according to Agassiz and
Desor,

11. Spatangus Requient,

12. Scutella pyramidalis, Risso; and

13. Spatangus bituricensis, Defrance.

C. ‘ Species” constructed out of the Gibbous form.

14. Spatangus gibbus, Lamarck. Micraster gibbus of Agassiz and
Desor, but not of the Catalogue Systématique. The figures in the
Encyclopédie Méthodique (pl. clvi., figs. 4, 5, 6) represent this pseudo-
species, which, however, has a fur more specific aspect than any of the
other varieties. Such extreme examples occasionally occur in England,
but are rare. The great development of the postero-lateral ambulacra,
resulting from the great elevation of the apex and the low position of
the vent, seems, at first, a sufficient distinction, but this character varies
much, passes distinctly into the variety next to be named, and through
it into more normal types.

15. Micraster brevis, Desor ; the Spatangus gibbus of Goldfuss, M-
craster gibbus of Agassiz (Cat. Syst.) The intermediate form between
No. 14, and more ordinary varieties. It is not uncommon in England,

8 BRITISH FOSSILS.

and graduates very gently into 14 on the one side, and the normal cor-
anguinum on the other.

Agassiz and Desor (whose declaration that forms are specifically
identical is pretty good warrant for considering them undistinguishable)
identify with this form

16. Spatanyus ananchytoides, Desmoulin, and, 17, Micraster latus,
Agassiz (Cat. Syst.) and Sismonda, whose figure represents the spe-
cimen only from above. It is fair to say that the Italian author, in the
‘“¢Memoir on the Fossil Urchins of Nice,” distinguishes his datus from
gibbus, referring the latter name to both Lamarck and Goldfuss. He
inserts Risso’s Spatangus sub-alpinus as a doubtful synonym of Jatus.
From the view which Sismonda, in the very excellent memoir cited,
one of the best papers on fossil Echinoderms with which I -am ac-
quainted, takes of the specific distinctions of Micrasters, in all probability
his datus should claim only to rank as a sub- -variety under the form
gibbus of cor-anguinum.

Thus seventeen forms, at fewest,—I fear more might be added,—
have been at different times regarded as distinct species; all of which
appear to be variations (many not even so much) of a single specific
type. In the ‘Catalogue Raisonné des Echinides” the authors hold
out of the number, six specific types of Micraster, viz., cor-anguinum,
Michelini, acutus, cordatus, brevis, and gibbus. But how acutus and
Michelini are to be separated from cor-anguinum it is difficult to under-
stand; whilst that cordatus (better known in England under the name of
rostratus) is a variety of cor-anguinum, few collectors even will be
inclined to dispute. As to the form called brevis, it is constantly
regarded in England as a variety of cor-anguinum, and most certainly,
as I have already said, passes into the normal type on the one hand, and
into the extreme gzbbus on the other, by almost imperceptible grada-
tions.

British Localities and Geological Range-—Cuak. It is found in
all the chalk districts of England; abundantly in many counties, as in
Kent, Sussex, and Norfolk. Its geological position is usually in the
upper chalk; it is recorded also from the lower chalk of Pinhay and
Charlton. The normal and rostrated forms are most common; the sub-
gibbous variety is next, and the extreme gibbous one rarest. Portlock
records it from the chalk of Magilligan, county Derry, in Ireland.

It is said to occur in the Sigs of Devon, but this is probably a
mistake.

Foreign Distribution —In ae chalk of France, Germany, Switzerland.
Sismonda finds it in the marly chalk in the neighbourhood of Nice.
Agassiz records the sub-gibbous variety from the chalk marl of Nor-
mandy, &c.; from the “‘ Craie chloritée of Coudrecieux (Sarthe) ;” and
from the chalk with Hippurites of Nice.

BRITISH FOSSILS. ‘ 9

DESCRIPTION OF THE PLATE.

Fig. 1. Specimen of the form 6 seen from above.

Fig. 2. The same from below.

Fig. 3. The same, posterior view.

Fig. 4, The same, lateral view. ao

Fig. 5. Ambulacral and interambulacral plates, showing the termination of the dorsal
petals of one of the lateral ambulacra.

Fig. 6. Spiniferous tubercles of dorsal interambulacral plates.

Fig. 7. Ditto of ventral plates.

Fig: 8. Base of one of the straight spines, greatly magnified.

Fig. 9. Outline of a young specimen of the elongated form (in Mr. Bowerbank’s
collection.)

Fig. 10. Outline profile of the normal form. ,

Fig. 11. Outline profile of the gibbous form (in Mr. Bowerbank’s collection.)

Fig. 12. Ditto of the sub-gibbous form.

Fig. 13. Granulation and tumidity of the ambulacral plates of the petaloid portion of
the dorsal ambulacra (highly magnified). This is the distinctive character of the species.

Fig. 14. A spine from near the anal region, figured from a specimen in Mr. Bower-
bank’s collection: the spatulate extremity is shown by its side.

Fig. 15. A portion of a spine, exhibiting a spirally rugose structure.

Note on Allied British Species.

Mr. Morris, in his valuable “Catalogue of British Fossils” (1843), enumerates ten
species of Micraster. Since the publication of that work the Brissoid species of the group,
as then received, have been séparated very properly by Agassiz. Only four of the names
there given, consequently, fall strictly under Micruster ; viz., cor-anguinum, cor-testudi-
narium, gibbus (for which both Lamarck and Goldfuss are cited), and rostratus. All of
them are here regarded as varieties of one species, viz., Micraster cor-anguinum.

There is, however, a Micraster found in our British chalk, which is very distinct from
cor-anguinum, and which does not appear to belong to any of the described species of
foreign authors. I have given an account of it in Mr. Dixon’s work on the Geology of
Sussex, where it is excellently figured. I have there named it Micraster cor-bovis. It is
usually a larger and longer species than cor-anguinum, and its petaloid ambulacra are
more deeply impressed and much shorter in proportion to the body. The shape is ovato-
cordate, the curve of the sides from the front of the antero-lateral ambulacra to the anal
extremity being but slight, its chief swelling being near the anus, and not on a line with
the end of the postero-lateral ambulacra, as in cor-anguinum. The back is more equally
depressed than in the depressed variety of the last-named species. The mouth is much
smaller comparatively, and the post-oral spinous space, though much longer, in consequence
of the elongation of the hinder portion of the test, is nevertheless proportionally broader.
The tubercles of the plates, whether dorsal or ventral, are much smaller and more scattered.
Besides all these comparative characters, there is the positive one that in cor-bovis the
ambulacral plates, instead of being tumid are smooth and plane, as are also the ridges
separating the sulcations of the pairs of pores in the petaloid ambulacra. The ambulacral
spaces are wider than the breadth of any of the sulcations. As contrasted with Cor-
anguinum, the diagnosis of cor-bovis would stand thus :—

[eex. x. | Cc

10 m BRITISH FOSSILS.

M. ambitu ovato-cordato, dorso convexiusculo, postice leviter arcuato, elongato ; ambulacris
dorsalibus impressis, assulis arearum ambulacralium dorsalium planis, levigatis.

I have seen specimens of this species, which attain a length of 3 inches by 23 at its
broadest part, and a height of 1 inch §, in the collection of the lamented Mr. Dixon of
Worthing, who had it from Sussex; in Mr. Bowerbank’s collection; and in the Museum
of the Geological Society, where there are specimens from Charing, Kent, presented by
Mr. W. Harris, and from Hemel Hempstead, presented by Mr. H. C. White,

In Mr. Bowerbank’s collection there are specimens, unfortunately not in sufficiently
good condition, of a small Micraster, with a very elevated extremity, from the lower
chalk of Lyme, which is possibly a distinct species.

Epwarp Fores.
June, 1850.

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MEMOIRS

GEOLOGICAL SURVEY

“THE UNITED KINGDOM.

Figures ond Deserigtions

BRITISH ORGANIC REMAINS.

DECADE IV.

LDLEPLD LD LPF PSP PL LPL SPILL LLL II LILI

PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY.

LONDON:
PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:
PUBLISHED BY

LONGMAN, BROWN, GREEN, AND LONGMANS.
1852.

Sale pire tel et

LONDON ! PRINTED ‘BY

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BRITISH FOSSILS.

DECADE THE FOURTH.

ALL the plates and descriptions in this Decade are devoted to fossil
Echinodermata of the order Echinoidea.

The genera selected for illustration are Temnechinus, Acrosalenia,
Hyboclypus, Hemipneustes, Ananchytes with its section Holaster,
and Cardiaster. The geological age of the first is Upper Tertiary,
of the second and third Oolitic, of the remainder Cretaceous.
Several of the species are represented for the first time.

Temnechinus is a genus remarkable for its species being at
present known only as fossils of the Coralline and Red Crags; it is
now characterized for the first time.

The examples of Acrosalenia selected are both remarkable for
their beauty and their very perfect condition. They are also of
much interest, one on account of the rectification of its true generic
position, which I have been enabled to make through the aid afforded
by very perfect specimens: the other, because of the complete
preservation exhibited by the specimens described of parts too often
lost in fossil Echinoderms. I have appended to the descriptions of
these Acrosalenie brief characters of some new species of this

interesting oolitic genus.

Hyboclypus is illustrated by the finest and largest species of the
genus, one discovered during the researches of the Geological

Surveyors.

[tVv.] b

4A BRITISH FOSSILS.

Hemipneustes, to which genus I unite Toxaster, is now for the
first time authentically represented by a British example, remark-
able for its novelty and for the light it throws upon the mutual
affinities of those genera of Hehinoidea which have excentric mouths.

The well known genus Ananchytes is combined (as indeed it
was formerly by Lamarck) with Holaster. In selecting the
common Ananchytes ovata of the Chalk for the subject of a plate
and description, I have been influenced by the necessity of clearing
up the confused synonymy of this fine fossil, and of settling the
numerous spurious species which have been constituted out of its
varieties, or from imperfect figures contained in old works.

Cardiaster is a new genus, lately constituted by myself for some
remarkable and interesting sea-urchins, intermediate in their cha-

racters between Ananchytes and the true Spatangide. To the ~

account of the species figured I have added notices of all the forms
of this curious type which are known. to me as British.
EDWARD IORBES.

October, 1852.

SE a gen ay

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M

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DECADE 4. PL.1.

Geological Survep of the Mrrted Ringoom.. TEMNE CELINE
( Tertiary ).. =

TEMNECHINUS ExcavaAtus Wood.

BRITISH FOSSILS.

DrEcADE LY. Puate I.

—_—

TEMNECHINUS EXCAVATUS.

[Genus TEMNECHINUS. Fornes (1852). (Sub-kingdom Radiata. Class Echino-
dermata. Order Echinoidea. Family Echinide.) Body spheroidal; ambulacral and
interambulacral segments developed, bearing on their plates, whose sutural margins
are excavated but not perforated on the dorsal surface of the test, tubercles of various
sizes, imperforate and placed on smooth bosses. Vent in the centre of the prominent
apical disk, which is composed of five genital and five ocular plates, all perforated.
Ambulacral avenues composed of pairs of pores indistinctly ranked; the ranks confluent
throughout. Mouth central, inferior, armed with a powerful dental lantern. Spines of one
order, but of various sizes. |

Synonyms. Temnopleurus Paes SeaRLES Woop, in Morris Cat.
Brit. Foss. p. 60. (1848.)

Temnopleurus Woodii, Acassiz, Cat. Rais. des Echin. in Ann. Sc. Nat.
3d series, t. vi. p. 360. (1846.) Temnechinus excavatus, ForBes, Brit.
Tert. Echin. p.6, pl. 1, fig. 1. [published by the Palezontog. Soc.] (1852.)

Diacnosis. TT. corpore depresso, superne subexcavato, sulcis suturalibus
Panis confluentibus.

It is very remarkable that a group of Echinide differing
@ontially and generically from any known assemblage should be
characteristic of the Coralline and Red Crag formations of England,
and at present be known only as confined to them. The type of
this genus is the form here described. I have named the group
TEMNECHINUS (reyvos, rcisus, and exevos).

This beautiful Echinite was originally named by Mr. Searles
Wood and placed by Professor Agassiz in his genus Temnopleurus,
under which it was enumerated by Mr. Morris in his catalogue.
But Temnoplewrus has imperforated tubercles elevated upon
crenulated bosses, a striking and easily recognized character, shared
also by Salmacis. Temnechinus accordingly will hold a position
intermediate between these genera and Echinus strictly so termed.
In the arrangements of its genital disk it exhibits considerable
peculiarities of its own. Its spines resemble more nearly those of

fiv.1] 4B

2 BRITISH FOSSILS.

Echinus than those of the other genera just mentioned. In the
disposition of the pores of the ambulacral avenues it approaches
Temnopleurus rather than Hchinus or Salmacis.

No Echinide with excavated sutures are now known to exist in
the European seas or in the temperate and colder portions of the
North Atlantic; they are all inhabitants of tropical seas, and
especially of the Indo-Pacific province. The fact of a group of
these sea-urchins having inhabited the British area during the epoch
of the deposition of the Crags would seem to indicate some ancient
relation between that region and seas to the south-east, probably
communicating with the Indo-Pacific.

The body of Temnechinus excavatus is of a depressed melon
shape. The ambulacra are a little more than half as broad as
the interambulacra. The former are composed of about 32 plates,
16 in each series. The three uppermost of these plates are
deeply excavated on their inner sides, and bear granules but no
tubercles on their more convex portions. The remainder bear
each a primary tubercle on the outer margin. They are all ex-
cavated rnore or less on their inner sides, the excavations of the
four or five upper ones becoming confluent, those of the remainder
forming distinct alternating oblong pits, which become smaller
and smaller until they are nearly obsolete in the neighbourhood
of the mouth. The elevated interstices form a ziczac ridge, the
outer angles of which join the bases of the primary tubercles ;
on this ridge are minute secondary tubercles and granules. The
plates of each interambulacral segment are about 20, ten forming
each vertical series. The two uppermost joining the genital disk
are smooth or nearly so; the remainder bear each a primary
tubercle not larger than those of the ambulacra. The four plates
next after the uppermost in each row are tumid on their outer
halves, very deeply and steeply excavated on their inner sides.
On the inner sides of the tumid portions are the primary tubercles
surrounded by secondary tubercles and granules. Their excava-
tions combined form a deep ziczac trench, smooth at the base.
The remainder of the plates are similarly ornamented with tubercles
and granules ; the sutural indentations, however, are not confluent,
but form deep loop-shaped smooth pits, becoming very small near
the mouth. The lines of division between plates run through the
pits. The avenues of pores are deep-set, and are composed of pairs
of pores separated by fine ridges and ranged in single file, the rows
being undulated. There are about 50 pairs of pores in each row.

BRITISH FOSSILS. 3

When the test is looked upon from above, the deep wavy furrows
are those of the imterambulacral sutures. Below, the indentations
are so slight that the surface at first glance resembles that of a
Salmacis.

The mouth is less than one third of the diameter of the test,
and one fourth wider than the breadth of the genital disk. It
is very obscurely ten-notched. The ambulacral arches are seen
within it, large, complete, and set obliquely.

The apical disk is composed of five perforated genital and five
_ perforated ocular plates surrounding the vent. The genital plates
are nearly equal, very elevated and prominent, with steep, smooth,
slightly excavated sides and triangular summits covered with
minute secondary tubercles (innermost) and granules. The madre-
poriform body is small and combined with the usual plate, the
contour of which it scarcely disturbs. The genital pores are placed
in the lowest and outermost portion, the smooth triangular pro-
jection in front of the base of each plate. ‘The eye plates are large,
pentagonal, and smooth, except a large obscurely defined gibbosity
or rudimentary tubercle rising on their centres immediately above
the eye-perforation, which is situated at their outer margins.

The primary spines are rather short and stout, with strong
articular bases. They are sulcated by about ten strong furrows ;
the intermediate ridges are broader than the furrows and as if
crenulated. The secondary spines appear to have been similar but
more slender and delicate.

A fine specimen measures 11ths of an inch in breadth by -3,ths
of an inch in height. Examples vary in their proportions. The
sulci are as strongly marked in an example little more than half
that size as in the large one.

In some of the earlier lists of Crag fossils a Cidaris is mentioned.
This Temnechinus was probably the sea-urchin intended.

Locality and Geological Position. Coralline Crag of Ramsholt
in Suffolk. I owe to Mr. Searles Wood, Mr. Charlesworth,
Dr. Clarke of Ipswich, and Mr. Bowerbank, the opportunity of
examining most of the specimens that have ever been found. A
fine example is contained in the Museum of Practical Geology, to
which it was presented by Mr. Searles Wood.

A, BRITISH FOSSILS.

EXPLANATION OF PLATE J.

Fig. 1. Upper side of Temnechinus excavatus, showing the deep and conspicuous inter-
ambulacral sulcations.

Fig. 2. Under side.

Fig. 3. Side view of the same specimen.

Fig. 4. The apical disk seen from above and magnified.

Fig. 5. The same seen laterally, showing the steep sides of the genital plates, and the
intermediate eye plates.

Fig. 6. Ambulacral and interambulacral plates, taken from the sides just below the
confluent sulci.

Fig. 7. Similar plates, taken from the neighbourhood of the mouth.

Fig. 8. An internal ambulacral arch.

Fig. 9. A spine highly magnified.

Note on the species of 'TEMNECHINUS.

I have met with four species of this genus, all of which are described in my
“ Monograph of’ British Tertiary Echinoderms,” contained in the publications of the
Palxontological Society. These are

1. Temnechinus turbinatus. Forbes.
From the Red Crag of Sutton.
2. Temnechinus excavatus. Wood.
3. Temnechinus melocactus. Forbes ; and
4. Temnechinus globosus, Forbes.
All three from the Coralline Crag.

EDWARD FORBES.
October, 1852.

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ACROSALENIA HEMICIDAROIDES.

[Genus ACROSALENIA. Agassiz. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinoidea. Family Echinide.) Body spheroidal, usually depressed ; ambulacral
and interambulacral segments developed, the former bearing two rows of small secondary
tubercles, the latter two rows of unequal large primaries ; tubercies perforate, and placed
on crenulated bosses. Anus excentric, included within the apical disk, which is formed of
five genital and five ocular plates, with one or more supplementary central plates. Ambu-
lacral avenues with the pairs of pores falling into single file above and on the sides, and
becoming distinctly three-ranked near the mouth. |

REFERENCE. <Acrosalenia hemicidaroides. Wricut, in Annals: and
Mag. of Nat. Hist., 2d ser. vol. viii. p. 161. pl. xi. fig. 1. (1851.)

Diaenosis. A. ambulacris angustis, tuberculis parvis approximatis
alternatis ornatis; interambulacris tuberculis primariis conspicuis, ad
latera magnis, superne parvis, areolis subconfluentibus; ared centrali
angustissima, granulata, granulis biseriatis.

This, one of the most beautiful and best preserved of British
Oolitic Sea-Urchins, has been for some years a well known orna-
ment of collections, but received no specific appellation until it was
described and figured in 1851 by Dr. Wright of Cheltenham, in his
excellent memoir on the Cidaride of the Oolites. i

The body is spheroidal, depressed above, usually considerably so,
but not always. At first glance its most striking features are
the large size and fewness of the interambulacral tubercles and
their bosses, whilst those on the ambulacra are very small and but
slightly spaced out. The interambulacral segments are centro-
laterally thrice the breadth of the ambulacral ones, and are some-
what prominent. The latter are narrow, gently and gradually
widening in the upper portion of their lower half, and exhibit a
shghtly undulating contour; they bear two rows of very small,
nearly equal, and prominent secondary tubercles, each row con-

sisting of (in large specimens) about 16, all of them perforated and

placed upon bosses, each of which exhibits about 10 crenulations.
[Iv. i1. | 7 4 C

vs BRITISH FOSSILS.

These ambulacral tubercles are separated from each other by narrow
and irregular rows of granules, and are so arranged, in consequence
of being closely set, that the tubercles of each row alternate. The
ambulacral segments are each composed of two series of six or
seven plates, each plate bearing a primary tubercle. The two plates
nearest the mouth bear small ones; those of the sides very large
ones, and those near the apical disk small ones. The tubercles
are elevated on very prominent bosses (to the size of which
their apparent dimension is chiefly due), around whose bases |
there is a broad smooth areola. The tubercles are perforate ;
the summits ofthe bosses crenulate; the number of crenula-
tions ten or more. The areole are confluent, separated by a
single line of minute granules. Alternations of minute secon-
dary tubercles and small granules closely set form a narrow
border to the ambulacral and interambulacral margins of each plate.
Thus the medial region of each interambulacral segment becomes
ornamented by a sinuous line of irregular secondary granules, two
abreast, except above, where they become rather more numerous,
until near the genital disk they become scattered or obsolete.
Their number is slightly increased in the ambulacral margins of
the interambulacral plates near the mouth. The mouth is wide,
usually equalling in width the height of the test. Its margins are
decagonal in consequence of ten deep notches with reflected edges
that indent in pairs the buccal extremities of the interambulacral
segments. The interspaces of these notches describe arches ; those
of the ambulacral segments being widest. The avenues of pores
are very slightly sinuous ; above, they are in strict single file; near
the mouth they fall into two or three somewhat irregular curved
ranks of three pairs in each. There is a small vee or granule
separating the pores of each pair.

The apical disk is wide and slightly convex ; it occupies about a
third of the diameter of the test. It is slightly pentagonal in
consequence of the projection of the genital plates. These are
large and escutcheon-shaped, except the posterior one, which is
contracted in consequence of the excentric and posteal position of
the vent, of which it forms one of the bounding plates. The genital
orifices are placed not far from their outer margins. The right
antero-lateral genital plate bears the madreporiform tubercle, in-
dicated by a porous subcentral space. The eye plates are large,
but the ocular pores are concealed in sub-marginal depressions.
The centre of the disk is occupied by from four to six supra-anal

BRITISH FOSSILS. 3

plates, or it may be regarded as composed of one plate broken up
into several elements. All the plates of the genital disk bear
scattered granules.

The primary spines are variable in size in the same and in
different specimens. They are shorter in young examples than in
old ones. In some before us, the largest spines are three times
as long as the diameter of the test. To the naked eye they seem
‘smooth, but under the lens are seen to be obsoletely and
finely striated longitudinally. They are more or less irregularly
angular; the angles rounded; in section they are irregularly
elliptical. They are broadest in their lower half, tapering upwards,
and terminating in a single, bifid, or trifid extremity. The ring
round their bases is narrow, elevated, and strongly crenulated. The
neck is very short, and the margin of the articular socket is strongly
crenulated also.

The secondary spines are very small, regular, round, and striated.

The dental-lantern is strongly developed, and often well pre-
served. It bears a close resemblance to that of Echimus.

The following table shows the comparative dimensions of three
specimens selected on account of their differences :

Elevated form. | Depressed form. Ordinary
smaJl example.

Diameter of test = =

1 inch. 1,4, inch. 0,5, inch.
Height of test - - OFS: Clee: eS,
Diameter of mouth - - OL ,, OL 5 0 5
Diameter of apical disk - 02, 04% » 03; »

The largest specimen in the Museum of Practical Geology
measures one inch and one-twelfth in diameter, and has spines
three inches and five-twelfths in length. The longest secondary
spine upon it measures one-fourth of an inch.

Locality and Geological Position. The finest examples of this
beautiful fossil were found by William Buy, an acute collector, in
the, Forest Marble near Malmesbury and Chippenham. We have it
also’from the same rock at Hinton Abbey, where it was collected
byZMr. Pratt. Mr. Bristow has found a tumid variety of it in the
Cornbrash near Wincanton. We have a group of specimens said

A, BRITISH FOSSILS.

to be from the Coral rag at Calne. Dr. Wright states that he has
collected it inthe upper beds of the Inferior Oolite at Leckhampton,
and that the Rev. P. B. Brodie has found it in the same stratum at
Selsley Hill; also that it is found in the Great Oolite at Minchin-
hampton, and at Kiddington in Oxfordshire.

EXPLANATION OF PLATE II.

Fig. 1. Body of the Acrosalenia hemicidaroides seen from above.

Fig. 2. The same seen from below, and showing the mouth.

Fig. 3. An elevated example, seen from the side. :

Fig. 4. A specimen in which the dental lantern is preserved.

Fig. 5. Apical disk, with its constituent plates and posteal anus.

Fig. 6. Part of the ambulacral and interambulacral segments, taken from the side. —

Fig. 7. Portions of the same segments from beneath, showing the three-ranked pairs of

pores in the vicinity of the mouth.

Figs. 8. 9. and 10. Primary spines of the natural size.

Fig. 11. The base of one of the primary spines magnified.

Figs. 12. and 13. Sections of primary spines magnified.

Fig. 14. Plan of the base of a primary spine, showing the crenulations surrounding the
socket and a second series above the neck.

Fig, 15. A secondary spine highly magnified.

Fig. 16. One of the interambulacral tubercles seen in profile, elevated on its crenulated
boss, the sides of which are slightly excavated and the base surrounded by an
areola.

Fig. 17. Portion of the dental apparatus.

EDWARD FORBES.
October, 1852.

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Geological Survep of the Married Kingdom. AGROSALENIA |
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ACGROSALENIA DECORATA — Hawmne.

BRITISH FOSSILS.

DecaDeE [V. Puate III.

ACROSALENIA DECORATA.

[Genus ACROSALENIA. Agassiz. (Sub-kingdom Radiata. ~ Class Echinodermata.
Order Echinoidea. Family Echinide.) Body spheroidal, usually depressed ; ambulacral
and interambulacral segments developed, the former bearing two rows of small secondary
tubercles, the latter two rows of unequal large primaries; tubercles perforate and placed
on crenulated bosses; anus excentric, included within the apical disk, which is formed of
five genital and five ocular plates, with one or more supplementary plates. Ambulacral
avenues with the pairs of pores falling into single file above and on the sides, and becoming
distinctly three-ranked near the mouth. |

Synonyms. Milnia decorata, Hame, Annales des Sciences Naturelles,
3d series, vol. xii., Zoologie, p. 217, plate ili. fig. 1. 2. 3. (1849.) -Acro-
salenia decorata, Wricut, Annals and Mag. of Natural History, 2d series,
vol. ix. p. 81. (1851.)

Draenosis. A. ambulacris tumidis, tuberculis minutis biseriatim dispositis,
remotis; interambulacrorum tuberculis antero-lateralibus mediocribus,
superioribus minimis, areolis omnium confluentibus.

In the twelfth volume of the “ Annales des Sciences Naturelles,”
M. Jules Haime has described and figured a remarkable Echinite
which he had seen in the collection of the British Museum, on
the supposition that the specimen in question exhibited characters
not met with in any known genus of Sea-Urchins, and that it
combined the anal arrangements of the Cassidulide with the
usual characters of the Cidaride, an union of structures hitherto
unobserved. He constituted for it a new genus, Milnea, and as
such features prevented its assignment to any family of Sea-
Urchins hitherto defined, he made it the type of a new family,
which he designated Pseudocidarides. Misled by the sound of the
name of the place mentioned as its locality, M. Haime considered
it as probably a tertiary species, and from Malta.

My prejudices led me, in spite of my esteem for the authority and
abilities of M. Haime, to doubt the probability of the existence of a
combination of characters such as those described and figured ; and
upon inquiry at the British Museum, my friend Mr. 8. P. Woodward,
who had shown the specimen in question to its describer, was
so kind as to submit it to me for a minute examination. The
result is, that the proposed new genus must be cancelled, and that
so far from presenting any extraordinary anomalies, this urchin
belongs (as Mr. Woodward, indeed, had been aware of before) to
the genus Acrosalenia. M.Haime had been misled by the im-

[IV. i11.] 4D

2 ; BRITISH FOSSILS.

perfection of the specimen and the casual examination which he had
been enabled to bestow upon it. Desirous of rectifying the error
before it might affect generalizations concerning the classification of
Echinoidea, I had the original example drawn in all its details
and engraved, and on a second visit of M. Haime to London, that
gentleman, on sight of more perfect evidence, at once candidly ad-
mitted the correction of his original description. Soon afterwards,
finding that my friend Dr. Wright having also met with this fossil,
was about to publish it as a new Acrosalenia under another name,
I communicated to him the engraving which illustrates this paper,
with the information of the appellation bestowed upon it by
M. Haime, and which was at once very properly adopted by
Dr. Wright, and appended to a full description of this species
published in the Annals of Natural History. Through the last-
named able naturalist I have been enabled to complete my analysis
of this curious and beautiful Echinite, by adding full particulars
and figures respecting the apical disk, and an account of the spines
belonging to it.

The body of Acrosalenia decorata is remarkable for presenting
a pentagonal outline, the five angles being- made by the five
ambulacral segments, which are tumid and rounded, whereas the
interambulacral divisions are depressed and as if flattened. Above,
this urchin is depressed ; beneath, it is hollowed out. The inter-
ambulacral areas are, centro-laterally, two and a half times as
broad as the ambulacrals. The latter bear two rows of small
secondary tubercles, each row distant from the other, and placed
nearly or quite marginally with respect to the segment, and having
the tubercles belonging to itself also ranged at regular distances.
In an ordinary specimen there are about twenty ambulacral
tubercles in a row. They are perforate, and placed on more or less
distinctly crenulated bosses. The centre of each ambulacral segment
is occupied by a rather broad band of nearly equal granules. The
interambulacral segments are each composed of two series of plates,
each plate bearing a prominent and perforated primary tubercle
placed on the summit of a crenulated boss, surrounded by a smooth
depressed areola. The outer and inner margins of each plate are
occupied by a raised granulated space of some breadth, and that
portion of the outer space immediately bordering the areolz has
two or three minute secondary tubercles at regular distances rising
among the granules. The central granulated (sutural) space on
each interambulacral segment forms a broad and conspicuous un-
dulated band. Of the ten interambulacral tubercles in each vertical

BRITISH FOSSILS. S

series, the three centro-lateral ones are very large and conspicuous ;
those between them and the mouth much smaller but still pro-
minent ; those between them and the apical disk very small and
inconspicuous. The areclee of the latter are but slightly depressed
and not well defined ; but the areole of all are often confluent ;
when not so, it is the uppermost tubercles only that are separated
by granules. The avenues of pores are very slightly sinuous.
The pairs of pores are set rather obliquely im single file, except
near the mouth, where they fall into indistinct ranks of threes.
The mouth occupies about half the diameter of the under surface,
and is lodged in a concavity with rounded and tumid sides.
It is distinctly decagonal and ten-notched ; the margins of the
notches are strongly reflected. |

The apical disk is oblong, with the vent excentric and placed
far back, so as to encroach in some specimens on the posterior
ambulacrum. It is not prominent but rather plane. It is com-
posed of five genital plates, five oculars, and from three to six
supplementary plates, one of which is regular and sub-centyral.
All are ornamented with scattered granules surrounded by well-
marked areole. The antero-lateral genital plates are large,
shield-shaped, and nearly regular. The postero-laterals are similar,
but somewhat oblique. Both bear their perforations sub-mar-
ginally within their projecting anterior angulated portions. The
posterior genital plate, bounding the vent, is very narrow and _
semi-lunar ; it has the perforation distinctly marked. The oculars
are well-marked, broad, and rather large ; the three anterior ones
symmetrical ; but the two hinder ones are unsymmetrical, being
narrowed and produced posteally. In all, the eye-perforations are
lodged in a marginal depression. The supplementary or sur-anal
plates are polygonal; the hinder ones smallest.

The primary spines are sub-cylindrical, subulate, and to the eye
appear nearly smooth; but under the lens they are seen to be
obsoletely striated. They are often slightly curved near their bases,
and have their neck-rings set obliquely. The longer ones exceed
somewhat in length the diameter of the body. The secondary
‘spines are very small, rather stouter in cicear® to their length,
and more distinctly striated.

The largest specimen which I have seen measured three-fourths
of an inch in diameter, had a disk three-tenths of an inch in
length by three-twelfths in breadth, and primary spines one inch
long. A smaller and more ordinary example is seven-twelfths of an
inch in diameter by four-twelfths in height.

A BRITISH FOSSILS.

Locality and Geological Position. Our specimens in the Museum
of Practical Geology were collected during the researches of the
Survey at Steeple Ashton and near Abbotsbury Castle, in both
instances in the Coral rag. Dr. Wright’s examples were collected
“from the yellow clays and ragstones of the Coralline Oolite in
Wilts.’ The specimen described by M. Jules Haime came from the
Coral rag near Malton.

DEscRiIPTION OF PLATE III.

Figs. 1. 2. and 3. Views of the original specimen upon which Miulnea decorata was
founded.

Fig. 4. A magnified view of the apical disk of the same specimen, in which, in con-
sequence of the very narrow and abnormally semi-lunar posterior genital
plate, and the loss of the anterior sur-anal plates, a large and ovate vent
appears to belong to the posterior ambulacral segment. It was this appearance
that misled M. Haime.

Fig. 5. Portion of the under surface highly magnified, showing the triplication of the
pairs of pores near the mouth, and the deep notches with reflected
margins.

Fig. 6. Ambulacral and interambulacral plates of the surface near the disk.

Fig. 7. Similar plates from the centro-lateral region of the segments.

Fig. 8. A primary tubercle with its crenulated boss.

Fig. 9. Primary spines of the natural size.

Fig. 10. The base of a primary spine magnified.

Fig. 11. Magnified view of a secondary spine.

Fig. 12. A plate from the disk.

Fig. 13. Outline of a very complete disk (from a specimen communicated by

Dr. Wright).

Note on undescribed species of ACROSALENIA.

1. Acrosalenia pustulata, sp. nov.

A. ambulacris angustis, tuberculis parvis in seriebus duobus approximatis subalternatis
dispositis ; interambulacrorum tuberculis centro-lateralibus magnis, superioribus minutis ;
areolis disjunctis ; area centrali angustissima, bigrannlata, granulis sparsis.

Diam. 4 une. Alt. + unc.

It resembles A. decorata, and holds a position between that species and A. Wiltoni.
The spines are very long, slender, and apparently smooth. (Mus. Pr. Geol.)
Locality. The Forest marble of Malmesbury.

2. Acrosalenia radiata, sp. nov.

A. ambulacris angustis, tuberculis parvis seriebus duobus approximatis alternatis
sub-divergentibus dispositis ; interambulacrorum tuberculis numerosis regulariter graduatis,
superne decrescentibus centro-lateralibus mediocribus, areolis disjunctis; area centrali
angusta pace eee, granulis sparsis.

Diam. 4, une. Alt. 3, une.

It has Eaves with ot, spinosa, but differs in having the primary tubercles iced
diminishing instead of suddenly decreasing above. (Mus. Pr. Geol.)
Locality. Collected by Mr. Lycett in the Great Oolite of Minchinhampton.

EDWARD FORBES.
October, 1852.

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BRITISH FOSSILS.

Decape IV. Prats IV.

HYBOCLYPUS AGARICIFORMIS.

[Genus HYBOCLYPUS. Agassiz. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinoidea. Family Cassidulide.) Body ovate or suborbicular, more or less
expanded and depressed. Ambulacra homogeneous, subsimilar, the three anterior ones
converging and separated. from the two posterior. Posterior interambulacral segments
with a deep longitudinal dorsal groove, in the upper extremity of which the vent is
lodged. Mouth central, inferior. Tubercles minute, perforated, and placed on crenulated

bosses. |

REFERENCE. Hyboclypus agariciformis, Forpes,—WricHt in Annals
and Mag. Nat. Hist. 2d series, Vol. ix. p. 99. (1851.)

Dracnosis. H. testé suborbiculari depressa sinuosd postice subtruncaté
ambulacris omnibus superne approximatis.

This fine species, the largest of its genus with which I am
acquainted, is of a suborbicular or obscurely pentagonal shape,
expanded, depressed above, (except when young and then it is
gently convex,) somewhat sinuate, rather acutely margined, and
strikingly mushroom-like in general aspect. Beneath, it is plain

and slightly sinuous. Usually its breadth slightly exceeds its

height,-and in old specimens the vertex is often depressed. Its
ambulacra, and also its interambulacra, are remarkably unequal.
The anterior or odd ambulacrum is in its widest dorsal portion
rather less than one fourth of the diameter of the contiguous part of
the antero-lateral interambulacra. The antero-lateral ambulacra
are slightly broader than the odd one, and narrower than the two
postero-laterals. The three anterior ambulacra converge around the
fore portion of the deeply excavated and pit-like apical disk. Their
terminations just impinge upon it, whereas those of the posterior
ambulacra which are sinuous and unsymmetrical, plunge into it ;
they are unsymmetrical chiefly in consequence of the sudden inward

turn made by the uppermost portions of their avenue border on the

anal side. The antero-lateral interambulacral segments of the back
are one fourth less in width than the laterals ; and these are broader

at their marginal portions than. the posterior interambulacral
[Iv. iv.] AE

2 BRITISH FOSSILS.

seoment, the margin of which is slightly truncate. The dorsal
surfaces of the anterior and lateral interambulacral, and of all the
ambulacral segments, are convex with a gentle curve, but that of the
hinder interambulacral segment is excavated by a deep longitudinal
furrow opening into the nearly round apical pit, narrow and steep
sided in its upper half, depressed and expanding in its lower
portion, where the sides of the segment are also flattened, and more
or less declining. The margin of the apical pit is notched with four
strongly marked interambulacral notches and five less strongly
marked ambulacral ones, the former correspond to the insertions of
the four perforated genital plates, and the latter to those of the five
ocular ones ; but no specimen has yet occurred exhibiting the minute

details of the disk. The whole of the plates of the dorsal surface

bear very numerous minute, regular, and nearly equal primary
tubercles, perforated, borne on crenulated bosses and lodged in a
depression forming an areola about each; they are separated from
each other by granules. These tubercles become still more numerous
and slightly larger on the marginal portions of the test, where they
are separated from each other by so narrow a line of granules that
each appears to be placed within an hexagonal frame. Towards the
mouth they gradually increase in size and become more separated,
with considerable numbers of granules keeping them apart. The
pairs of pores are ranged in the avenues dorsally in single file, but
when they turn the margin and pass on to the under surface they first
oradually fall into oblique sets of three pairs, and eventually, close
to the mouth, into very oblique ranks of threes. The mouth is
excentric in the opposite direction from the apical disk, for whereas
the latter is excentric towards the posteal extremity, the mouth is
excentric towards the anteal margin. The mouth is longer than it
is wide, and has rounded slightly tumid lips ; the spines are minute
and very short, subulate and finely striated.

Dr. Wright has met with a specimen three inches and ;8ths
in diameter. A fine example in the Museum of Practical
Geology measures 2 inches and ths in length by 2 inches -%,ths

1

in breadth. The greatest thickness is -8,ths of an inch. From

T@
vertex to posterior margin it measures | inch and -3,ths, and to the
anterior margin | inch and -4,ths ; the anterior and antero-lateral
ambulacra are -2,ths of an inch in breadth; the postero-laterals —*ths
of an inch in breadth. The length of the mouth is =3,ths, and its

breadth -2,ths of an inch. The breadth of the anal furrow just

below the apical concavity is -2,ths of an inch.

EL ST ee SCPE Ye ae
paee ae a . id .
7 iat

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Sai

Ree st eee ee et

BRITISH FOSSILS. 2

A young specimen exhibits different proportions; it is one inch
and -2,ths in length, by 1 inch and -8,ths in breadth. Its height is
three fourths of an inch.

Locality and Geological Position. The specimens in the collec-
tions made by the Geological Survey are all from the Inferior Oolite.
They are from the pea-grit of Crickley Hill in Gloucestershire, where
they occur in company with the rarer Hyboclypus caudatus ; from
between Wayford and Seaborough in Dorsetshire, where they are
accompanied by Dysaster rungens and Galerites (Holectypus) hemi-
sphericus ; and at Camlong Down near Uley Bury.

Hyboclypus gibberulus has been met with during the progress of
the survey near Bridport, and in two other localities in Dorsetshire.

In figuring this species we are much indebted to Dr. Wright for
his kindness in permitting us to make use of some fine examples in
his possession.

EXPLANATION oF PLATE IV.

Fig. 1. A large specimen of Hyboclypus agariciformis seen from above.
Fig. 2. The under side of a smaller example.

Fig. 3. Terminal view.

Figs. 4. and 5. Outlines of a less expanded specimen.

Figs. 6. and 7. A young specimen, much more convex.

Fig. 8. Dorsal ambulacral and interambulacral plates.

Fig. 9. Ambulacral and interambulacral plates of under surface.

Fig. 10. Arrangements of the apex and anal groove.

Figs. 11. and 12. Tubercles and granules.

EDWARD FORBES.
October, 1852.

Geological Survep of the Unites Kingdom. HEMIENEUSTES

(Cretaceous)

93:
P33,

p73}
BPE,

SiBo,2

5
Sees oO 30;
Le ep camanead

‘

HEMIPNEUSTES. GREENOVIL_ Forbes.

BRITISH FOSSILS.

DecapE TV. PLATE V.
HEMIPNEUSTES GREENOVIL.

[HEMIPNEUSTES. Acassiz. (Sub-kingdom Radiata. Class Echinodermata. Order
Echinoidea. Family Spatangide.) Body cordate, more or less tumid, in some species
much elevated ; ambulacra dissimilar, the lateral ones dorsally curved, petaloid or semi-
petaloid, the odd one straight and lodged in a sulcus. Vent terminal supra-marginal.
Mouth excentric, transverse. No fascioles. Genital pores four. Tubercles minute, per-
forated, placed on crenulated bosses. |

Hemipneustes Greenovit. Sp. Nov.

Dracnosis. 7. testa tumidd ambitu cordato ; ambulacro. antico ports
superne -dissimilaribus alternatis ; ambulacris antero-lateralibus serié ex-
terno pororum angusttssimo, postero-lateralibus seriebus sub-similaribus.

This curious and rare Echinite presents characters which distin-
guish it very strikingly from any described species. Its characters
link together the genera HEMIPNEUSTES and ToXASTER, hitherto
placed apart, even in different groups, the former being usually
associated with Ananchytes, the latter with Micraster.

The well known Hemipneustes radiatus of the Maestricht
Chalk is the type of its genus. In general contour it resembles an
ee but eentinlly differs in the structure of the test, for

nstead of the ambulacra being all similar and formed of homo-
geneous or nearly Ueimootnetne: parts throughout, the lateral ones
are very unlike the anterior one, the former being partially petaloid,
and the latter rectilinear. Its lateral ambulacra are, moreover,
remarkable for being composed in their. petaloid portions of
differently constructed avenues, the hinder avenue of each being
made up of pores widely separated and connected by a broad groove,
whilst the fore one is made up of minute and closely approximated
pairs of pores.

The genus Toxaster, on the other hand, was instituted for those
heart-shaped urchins that resemble Holaster in general aspect, but
have subpetaloid ambulacra‘in the manner of Micraster, differing,
however, materially. from the latter in the absence of any kind of
fasciole. The depressed or slightly tumid shape of most of the
known species is so very unlike that of Hemipneustes radiatus,
that no comparison seems to have been instituted with it. Essen-

[Iv. v.] 4 oF

2 BRITISH FOSSILS.

tially, however, there appears to be no generic distinction between
them, for though in several Toxasters the difference between the
two series of avenue pores in the lateral ambulacra is very slight
and indistinct, in others it is as great as in Hemipneustes proper.
In Toxaster complanatus for example the two avenues of each
lateral ambulacrum are similar ; so are they also nearly but not
quite in Toxaster gibbus (Agassiz), T. Ricordeanus (Cotteau), and
T. Niccensis (Sismonda). But in Toxaster oblongus (Deluc) and
T. Verany (Sismonda) they are nearly as dissimilar as they are in
Henmipneustes radiatus ; and in the species now to be described the
antero-lateral ambulacra have dissimilar avenues, and the postero-
laterals nearly similar ones. Unless the Toaster oblongus,
T. Moulim, T. semistriatus, and T. Verany be regarded as
species of Hemipneustes, and the name Toaster be confined to
those species resembling 7. complanatus in the arrangement of the
pores, (in which case my new species would become the type of a

new and intermediate genus,) these two groups must be considered.

as forming but one natural genus. Such indeed is the view that I
take of the assemblage, and the name Hemipneustes, as the older
appellation, had best be retained for it.

The Hemipneustes Greenovit has a regularly cordate outline
truncated posteriorly. It varies greatly in degree of tumidity, but
appears always to present a high apex and hinder half, whilst the
portion in front of the centre declines with a gentle curve, and is
divided into two tumid cheeks by the rather deep and. wide but
not abruptly margined central furrow. ‘The hinder extremity is
perpendicularly truncate; and bears the vent at about half the height
of the back. The under surface is flattened, but very slightly
convex, and rounded at the side. The mouth, which is transversely
oblong, is placed in a depression very near the anterior margin,
opposite to the anteal. furrow.

The ambulacra require to be separately described. The odd one
is one third wider than the laterals. It preserves nearly an equal
width throughout, and is composed of plates which become con-

tracted vertically throughout its upper half. Out of about 37 plates”

geen in each of its two series, the lower seven are square or oblong,
and large. They are each perforated near their outer and lower
corners by a pair of minute approximated pores. In the narrow
plates above these a very curious change takes place in the avenue
arrangements for the pairs of pores; all become conspicuous, are
alternately approximated, and set widely apart ; the latter pairs
each consisting of a long outer pore and a short inner one. Inside

BRITISH FOSSILS. 3

of the pores there is a very small tubercle or two on each plate,
the rest of the surface being covered by minute and closely set
granulations ranged in transverse rows. ‘The antero-lateral am-
bulacra are undepressed and superficial, and exhibit a slight and
graceful curve ; they are composed of an inner series of minute and
approximated pairs of pores and of an outer or hinder series, in which
the pores of each pair are widely separated and unequal (the outer
ones being longest), and connected by a shallow groove. There are
about 30 pairs of pores in the petaloid portion of each series; the
petals gradually become narrow and cease about half way down
the sides. In the postero-lateral ambulacra, the petals are also
plane and undepressed, but are more regularly lanceolate in shape,
in consequence of the two series of pairs of pores in each being of
nearly similar structure and but slightly unequal in width. There
are about 18 pairs in each petaloid avenue. A few tubercles are seen
upon the lateral ambulacra. On the interambulacral spaces they
are much more numerous, though set well apart and much larger.
They are largest on the anterior segments, where they have wide
areole. Their interstices over the whole of the test are occupied
by minute granules, which are, however, not so small or so regu-
larly arranged as those on the odd ambulacral plates. On the
under surface the tubercles are confined for the most part to the
interambulacral spaces, and are especially numerous, regular, and
closely set on the ovato-lanceolate post-oral space formed by the
inferior portion of the hinder interambulacrum. This space exhibits
a prominent caudal gibbosity. The tubercles are minute and per-
forated ; they are elevated upon crenulated bosses. The spines are
unknown.

The apical disk is small, and is composed of four perforated

-genital plates, the perforations of which are approximated. In the

midst of them is seen the madreporiform body. A. fifth genital

plate is imperforate. The five ocular plates are all perforated, but

very minute.

The larger of the two specimens figured measures 1 -4, inch in

length, the same in breadth, and one inch in height. The smaller
is 1 4, inch in length, the same in breadth, and ,8,ths of an inch in
height.
Locality and Geological Position. The Greensand of Blackdown
in Devonshire, a formation whose geological horizon is probably
about the junction of the Gault and Upper Greensand, if it be
not a local condition of the Gault itself The specimens described
are in the Musewn of Practical Geology.

A BRITISH FOSSILS.

EXPLANATION OF PLATE V.

Figs. 1. 2. 3. and 4. Represent various views of the more tumid variety.

Fig. 5. Is a profile of the depressed form.

Fig. 6. Ambulacral and interambulacral plates from the postero-lateral segment.

Fig. 7. Arrangement of the pores in the ambulacral avenues and structure of the
apical disk. : ;

Figs. 8. 9. and 10. Illustrations of the dispositions of the pores in the anteal am-
bulacrum.

Figs, 11. and 12. Primary tubercles and granules, magnified.

Note on another British species of HEMIpNEUSTES.

In lists of British fossils from the Lower Greensand a “ Spatangus complanatus” is
often mentioned, and referred to as the Holaster or Toxaster complanatus of the Neocomien
of the Continent, a species upon which much stress has been laid by those geologists who
have described foreign localities. In Mr. Morris’s catalogue the Holaster complanatus is
made synonymous with the Spatangus retusus of Lamarck and Goldfuss, and the Spatangus
argillaceus of Phillips, which last-named fossil, judging from the figure given in the
“ Geology of Yorkshire,” was an Ananchytes of the subgenus Holaster. The Upper Green-
sand of Wilts, the Gault of Speeton and Folkestone, and the Lower Greensand of Kent
aud Hants have been enumerated as formations in which the supposed “ Holuster com-
planatus” is found. In Dr. Mantell’s Medals of Creation (p. 355. lign. 84.) there is indeed
a figure of “ Spatangus complanatus, Chalk Marl, Hamsey,” which, being evidently a
representation of the true species of that name, might seem to imply not only that it is
really British, but also that in England it is found in a very different geological position
than on the Continent. But a comparison of the figures in question with those in Plate 2.
of the “ Echinodermes Suisses” shows that they are copies or tracings of the excellent
representations of Neocomien, ie. Lower Greensand examples, given by Agassiz im that
valuable work. Probably Holaster subglobosus was the species intended by Dr. Mantell,
and really found by him in the Chalk Marl of Hamsey. The specimens which have been
mistaken for Toraster complanatus in the Wiltshire Greensand were possibly my Hemi-
pneustes Greenovit; those that I have seen so called from the Gault belong to more than
one species of Hemiaster, and that from the Speeton clay was either a Holaster or a
Cardiaster crushed. I have also seen examples of Cardiaster Benstedi marked Spatangus
complanatus or S. retusus.

I can find no evidence whatsoever of the occurrence of the true Toxraster (i.e. Hemi-
pneustes, as now redefined) complanatus in British strata. Very distinct sea-urchins,
members of no fewer than four different genera, have been imtended by that name in
British lists.

One of these, a Lower Greensand species referred to by Dr. Fitton, is really a Hemi-
pneustes of the section Yoxaster. It differs however specifically from any known species,
and I have named it Hemrpnreustes (Toxaster) Firront.

It has the test tumid, ovate, depressed above, rounded inferiorly, with a shallow anteal
sulcus. The lateral ambulacra are partially petaloid, and in that portion of their length
lodged in very slight depressions. The avenues of pares in the odd ambulacrum are placed
rather widely apart. Those of the antero-lateral ambulacra are slightly sinuous, and the
outer ones are very Slightly broader than the inner. There are about 36 pairs of pores in
the petaloid part of each row. The postero-lateral ambulacra are much shorter and more
symmetrical, and have about 16 pairs of pores in their petaloid parts of each row. The
tubercles on the plates are small, pretty equal, and scattered profusely.

The dimensions of a moderately large specimen are one inch and ;4,ths in length, one
inch and 2,ths in breadth, and ten-twelfths of an inch in height.

In the Museum of Practical Geology is a specimen from Horseledge Point, *near

Shanklin, Isle of Wight, presented by Dr. Fitton, and another from Hythe, presented by ~

Mr. H. B. Mackeson ; both from the Lower Greensand.
October, 1852. EDWARD FORBES.

DECADE 4. PL.

ANAN GEHIVTE

( Cretaceous )

ANANCHYTES ovata __ Zeske. oe

BRITISH FOSSILS.

DECADE IV.:> Puate VI.

_—

ANANCHYTES OVATA.

[Genus ANANCHYTES. Lamarck. (Sub-kingdom Radiata, Class Echinodermata.
Order Echinoidea. Family Ananchytide.) Body suborbicular; oblong or obscurely
cordate, tumid; with homogeneous ambulacra, convergent on the vertex, all plane or
with the anterior ambulacrum in a shallow furrow. No fascioles. Vent terminal, marginal
or supra-marginal. Apical disk elongated and composed of four perforated genital and
five perforated ocular plates. Tubercles perforate; their bosses crenulate. Spines
minute. No dental apparatus.

Subgenus AnANCHYTES. Body ovate or orbicular ; vent infra-marginal. |

Dracenosis. A. ambitu ovato seu orbiculari, antice rotundato ; testd
alté tumidd, ano infra-marginali.

Forma a, alta, hemispherica, ambitu ovato.
ANANCHYTES OVATA and CONOIDEA, Auctorum.

Forma ~, (alia) elongata, superne depressa, ambitu ovato.
ANANCHYTES STRIATA, Auct. ? OVATA pars.

Forma y, alta superne depressa, ambitu orbiculari.
ANANCHYTES GIBBA, Agassiz.

Forma 6, subglobularis.

Forma ¢, alta, conica.
ANANCHYTES CONICA, Agassiz. A. PYRAMIDATA, Portlock.

Synonyms. Lchinocorys vulgaris, Breyn. Sched. de Echinis. p. 58.
pl a. f. 1. 2. (1722.)

Echinocorytes ovatus, Luske ap. Kuri. Nat. Disp. Echin. p. 178,
pl. 53, f. 3., also Echinocorytes pustulosus, p. 180, pl. 16, f. A.B. Echino-
corytes scutatus, p. 175, pl.15, A. B., and pl. 42, f.4. Eehinocorytes minor,
p: 183, pl. 16, C. D.; and_17, a. b.-(1778.)

Echinus ovatus, scutatus and pustulosus, Linneus.

Ananchytes ovata, striata, gibba, pustulosa and semiglobus LAMARCK. An.
sans Vert. vol. ili., p. 25, 27.

Ananchytes ovata, conoidea, striata, gibba, pustulosa, hemispherica, semi-
globus and corculum. CC. DEesmovtins, Etudes sur les Kch., p. 368-376.

Ananchytes ovata, gibba, striata, Gravesii? semiglobus and conica,
AGassiz. Cat. Syst., and Agassiz and Dzesor, Cat. Raisonné des Echinides,
in Ann. des Sciences Nat. 3d series, Zoologie, vol. viii. p. 30.

[IV. vi.] 4G

BRITISH FOSSILS.

Ananchytes ovata. Goxpruss, Petref. Germ., p. 145, pl. 44, f. 1.
Bronn, Lethea., t. 29, f. 23. Hisinaer, Leth. Suec. p. 98, t. 26, f. 8.
GeEIniITz, Grundriss der Verst., p. 382, t. 22, f. 19. Cuv. and Bronen.
Geol. Paris, p. 15 and 390, pl. 5, f.7. A. B.C. Manrerz, Medals, p. 349.
lien. 79. Porrtock, Rep. Geol. Londonderry, &c., p. 354, pl. 17, f. 3. and
18, f.2. Picret, Traité Elem... vol. iv, pl 5, f. 3., AGassiz, Jaehume
Suis. 1., p. 30, pl. 4, £9, 4, 6, (var. conica). “ SismonpaA, Ech. Foss. Nizza.,
p- 18. Rormer, Nord. Deutsch. Kreide Geb., p. 39. |

Ananchytes striata. Goutpruss, Pet. Germ., p. 145, plate 44, fig. 3, a.f.

GRATELOUP, Ours. Foss., p. 60, pl. 2, f. 9.
Ananchytes conoidea. Go.tpruss, Pet. Germ., p. 148, pl. 44, f. 2, a. b. e.

GRATELOUP, Ours. Foss., pl. 2, f. 8.
Ananchytes hemispherica. Cuy. and Bronen, Geol. Paris., p. 890, pl. 5,

f. 8, A. B. C.
Ananchytes corculum. Goupruss, Pet. Germ., p. 147, pl. 45, f 2,

His iO! eC
Echinites scutatus. SCHLOTHEIM, Petref. p. 319.
Echinocorys scutatus. Parkinson, Org. Rem. vol. ui. pl. 2, f. 4.
Eichinocorys scutatus ovatus. MAaAntey, Geol. S. E. Eng. p. 373.
Ananchytes cretosus. MAntreLi, Wonders, p. 31], t. 52, f. 5.
Galea ovatus. Swrtu, Strat. Syst. p. 21. Upper Chalk Plate, fig. 10.

After many attempts to frame a concordance of the synonyms of
this well known Echinite, I have been obliged to give up in
despair, and even to displace their chronological order. In the
above catalogue, which might be swelled to three times its dimen-
sions by useless references to mere mentions of this species, I have
placed in first rank the references to Breyn and Leske, since to
them, and especially to the figures of the last-named author, all |
subsequent writers refer back. Next in order I have placed the
references (in lump) to Lamarck, Desmoulins, and Agassiz, authors
who have given catalogues of species, and whose lists in this case,
according to my views, resolve themselves into a multiplicity of
names for the varieties of one thing, names too which cannot be well
reconciled with each other. Lastly, follow references to authors
most of whom have given original figures of the species, in one
variation or other, ranked in general in order of importance of
quotation rather than priority of date. All the figures cited in
these synonyms are preceded by a very good representation given by
Dr. Plot in his Natural History of Oxfordshire (1677), delineating
a flint cast of one of the ordinary forms of this Echinite.

It is to be regretted that the original appellation: given to this
fossil by Breyn, who styled it Echanocorys vulgaris, and
figured it much better than Leske did, was not retained. Now,

<i ae alli

BRITISH FOSSILS. 3

however, it is best for the convenience of science to preserve the
Lamarckian name Ananchytes ovata, although originally given to
one of the varieties only. Lamarck’s names seem to be little better

than so many designations for Leske’s figures, not one of which, in

this instance, deserves to be separated from the others as the type
of a distinct species.

Goldfuss gave admirable representations of what seemed to him
to be three or four distinct specific types, and applied to them in
two instances the names used by Lamarck.

Agassiz and Desor admit eight species of Ananchytes, using the
generic term in its most restricted sense. As all but two of these
are types of which good figures are published, and as I consider all
of them, except sulcata, to be probably varieties of one species, it
is desirable that a few critical remarks should be made upon the list
given by the distinguished naturalists just mentioned.

For Ananchytes ovata (Lamarck) they refer to Goldfuss’s figure
designated by the same name. This is my Forma a, and may be
considered as the normal type of the species. The figure in Leske’s
work referred to by Lamarck as the representation of his ovatus is
not exactly this, but one of the connecting links between my
Forma « and Forma « The Ananchytes corculum, jyadging
either from the old figures of Leske or the excellent ones of Gold-
fuss, is, it seems to me, the young of this form. I have received
under the MS. name of Ananchytes Bayjfieldi a similar young
specimen. Portlock’s first examples of Ananchytes ovata are of
the normal type.

The second species in the “Catalogue Raisonné,” Ananchytes
gibba (Lamarck), is identified by Agassiz and Desor with the
A. rustica of Defrance, and for a figure they refer to A. striata var.
subglobosa of Goldfuss ; that figure represents an example of my
Forma y ; not, however, of the extreme type of that variation, but
rather of a specimen inclining towards Yorma 8. The figure in
Leske, referred to with a query by Lamarck, is still more near 8,
or rather is between 6 and a.

The third species in the “Catalogue Raisonne” is Ananchytes
striata (Lamarck). In collections, full-bodied, long-topped, and
comparatively smooth-sided Ananchytes are usually labelled with
this name. Ananchytes conoidea and striata var. marginata of
Goldfuss are referred to it; the former is a lofty example of my
variation 8, the latter a specimen intermediate between Band «. The
A.conoideus of Portlock is truly this form; the A. hemispherica

4 Gq 2

4 BRITISH FOSSILS.

of Brongniart is intermediate between it and the normal — The
A. pustulosa of Lamarck, founded on a figure by Leske, should
surely rather be referred to a specimen intermediate between a
and «, and nearest «.

The fourth species, Ananchytes Gravesii of Desor, has never been
figured or described at length, but from the brief note concerning it
I think it may prove to be a form intermediate between 6 and 8.

The fifth, A. tuberculata, Defrance, is probably truly distinct.

The Pik A. semiglobus (Lamarck), seems to be an intermediate
form between « and «, The figure in Leske is that of a young a.

The seventh, A. conica, Agassiz, has its extreme form in
pyramidata of Portlock, and its variation passing into the normal
type through the Ananchytes ovata figured in Part I. Plaiie: A,
figs. 4-6, of the Echinodermes Suisses.

The abundance of this Ananchytes in our Upper Chalk, and the
fine state of preservation in which they are usually found, has
enabled me to examine minutely and compare a great number of
specimens ; an inquiry the more desirable, as, according to some

naturalists, and those of high repute, there are many species of the ~

strict Ananchytes type, allies of A. ovata, whilst the experience
of British collectors would rather incline in favour of the view that
we have but a single species, exhibiting numerous variations. To

this last view I feel compelled to assent, for however distinct the

forms termed ovata, gibba, striata, seni-globus, conica, &e., may
seem when selected and contrasted in the cabinet, every one of
them is linked with the others by the most delicate shades of
gradation. Neither in degree of elevation, rotundity, flatness
of base, or curve of back, smoothness or roughness, can I find any
constant character. Scarcely two individuals out of more than a
hundred examples now before me exhibit the same proportions.

The specimens vary in outline of base from ovate or oblong to nearly
round, and in outline of back from that of a depressed oblong
hemisphere to an abruptly-sided pyramid. They vary also in degree
of granulation of surface, in the number of primary tubercles, and
in the height of the ambulacral and interambulacral plates. The
number and proximity of pores in the avenues increase with age.

In a well-ecrown adult example, above 23 inches in height, the
dorso-lateral plates of the ambulacra are between 40 and 50 in
number, and of the inter-ambulacra about half that amount. Ina
specimen linch 4 in height the number of the ambulacral plates
is under 30, and of the inter-ambulacrals balf that amount. The

BRITISH FOSSILS. 5

differences in the number of the plates of the inferior surface are not
so great.

The ambulacra are, dorso-laterally, at about the centre of the sides,
in breadth to the interambulacra as 1-3. This proportion varies
a little in different specimens, but without much regard to the
general contour. Except in size, they exactly resemble the ambu-
lacrals. On the upper third of the test they are small, short, and
closely set; then gradually become taller down the sides and as
they approach the margin. They and the interambulacrals are
similarly ornamented with minute scattered primary tubercles,
each of which is perforated and set upon a boss with a crenulated
summit. On a large interambulacral plate in one of the rougher
varieties | have counted as many as fifty tubercles, and yet they
appear wide apart. The interspace is studded with scattered
miliary granules forming imperfect rings around the tubercles
In an individual of one of the smoother varieties there may not be
more than about fifteen tubercles upon the corresponding plate.
The pairs of pores occupy each an ambulacral plate, and are placed
near its centre, slightly oblique, a very shallow groove connecting
the one pore with the other. In consequence of their closeness
they are conspicuous near the apical disk, but are inconspicuous on
the sides.

The base varies in degree of flatness, and specimens are occa-
sionally found remarkably rounded at-the margins ; usually, how-
ever, it presents an extensive flattened surface. At one extremity
of it is seen the longitudinally elliptical vent, near the other the
transversely oval mouth. The space between the mouth and vent
is plane, and occupied by the subanal plates of the posterior inter-
ambulacral segment. There are about six of these plates in each
alternate row, and their inner margins are curved hindwards.
They are covered with tubercles, thickly set, and consequently con-
trasting with the bordering inferior ambulacral plates, which are
minutely granulated but not tuberculated, and present the aspect of
a lanceolate rough space or elongated escutcheon, the base of which
is formed by a raised ovate leaflike space in front of the vent,
marking the position of internal buttresses. The tubercles on the
anterior portion of this space are smaller than those of its hinder
half and than those of the escutcheon that embraces it. They are
also more scattered, and are more separated by minute granules.
The postero-lateral ambulacrals in their basal portion are elongated
to reach the mouth, and their plates become longer and somewhat

6 BRITISH FOSSILS.

polygonal, so that the pores are more distant than they are on the
sides and margin. The other ambulacra, in consequence of the
exceedingly excentric position of the mouth, near which they widen
out, are much shortened and close set below, and the pores of all
five in the immediate neighbourhood of the mouth form a sort of
irregular star, the longest rays of which are formed by the buccal
extremities of the antero-lateral ambulacra. The mouth is lodged
in an oblique depression ; its lips are thickened ; the hinder one is
highest, but does not overlap. The vent is set obliquely and sub-
marginally.

The apical disk is much elongated. It is composed of four large
and perforated genital plates (the fifth is usually obsolete) and five
large oculars ; of the two anterior genital plates, the right one is the

largest, in consequence of its including the madreporiform body in its

constitution. This organ is not conspicuous, but under the lens
its punctations, which are exceedingly minute, may be detected.
Of the two hinder genital plates, the left one is largest. They are
all polygonal. Of the ocular plates, the two antero-laterals are

much larger than the other three plates. The eye perforations —

are marginal; the genital holes sub-central. All the plates are
thickly covered with granules and bear a few tubercles. On flint
casts the position of the central portion of the apical desk is marked

by a space included within an oblong groove. This groove is ©

caused by the impressions of the walls of a solid oblique tube-like
body projecting from the inner surface of the apical disk into the
cavity of the test, and directed backwards. This organ appears to
me to be the sand canal, and is connected with the madreporiform
plate. On flint casts the pores of the avenues are seen strongly
projecting, and on each side of the vent is a shallow groove mark-
ing the place of internal strengthening buttresses.

The following table exhibits the comparative measurements in
inches and the configuration of the dorsal contour, in seventeen
examples, all differing strikingly from each other.

q Form of
Se Height. Length. Breadth. | binder dorsal inter~
eee ambulacra! area.

Contour of
the dorsal surface.

eS en | ee | nr RR

1 2445 Oy 213 Rounded - | Very wide and
flattened.

2 245 333 255 Carinated - | Wide and flat.

4 ty
- = ‘ ; : eS
ee a ee tn '

’
#
4
i
3
&

BRITISH FOSSILS. 7

Spe- Height Leneth Breadth els eee. Contour of

cimen Sasa ory, Scaife ep cea oth the dorsal surface.

3 2,5 335 3 Carinated - | Wide and rather

flat.

4 2-55 3485 235 Carinated - | Wide and _ very

flat.

5 285 3435 2.4, | Much carina- | Gently declining
ted and ele- from apex.
vated.

6 2435 a= 22, | Rounded - | Gently curving.

7 2.3, ae 2.3, | Carinated - | Gently curving.

8 113 211 245 Carinated - | Flattened slightly.

9 1,5 255 119 Carinated - | Flattened.

10 Jit 2,5, 25 Carinated -| Gently curving,
and slightly
flattened.

rf 27h5 2445 275 Carinated - | Curving.

12 2-35 2435 2.3. 7| Carmated....- |, Flattened.

13 2555 3x4 25 Carinated - | Rapidly curving,
and _ flattened

~ behind.

14 oe 2it 235 Sub-carinated | (Tumid below, and)
Conic above.

15 2.5, ae 2,3, | Carinated - | (Tumid below, and)
Conic above.

16 1,8, | ae 1.8: Carinated - | Conical, with

12 12 12 ;
| slightly curved
sides.

17 2375 2 [ee Sub-carinated | Pyramidal, with

straight sides.

The last specimen in this table is the original example of Anan-
chytes pyramidata of Portlock, and the most extreme of all the
varieties.

Locality and Geological Position. A. ovata is a characteristic
fossil of the White Chalk, and is found abundantly in the south-east
of England, especially in Kent, Surrey, Sussex, and the Isle of Wight.
It occurs in both middle and lower parts of the series. Forma
subglobularis and 8 striata are prevalent in the Lower Chalk. In

8

Ireland Colonel Portlock observed Forma a ovata to be charac-
teristic of the lower beds there. In England that variety is chiefly

from the upper beds. All the varieties occur as flint casts among

BRITISH FOSSILS.

gravel. :

Specimens with slightly tumid plates from County Derry) in
Ireland were referred by Portlock to the Ananchytes sulcatus of 1
Goldfuss, a Maestricht species. They are, however, unquestionably q

only peculiar examples of A. ovatus.

The supposed British Hemi- 4

pneustes radivatus recorded by Dr. Mantell is only Ananchytes
ovatus, as the original examples in the British Museum show.

EXPLANATION OF PLATE IV.

Figs. 1. 2. and 3. Different views of an example of the common Forma a.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.
Fig.
Fig.

4
5
6
7.
8
9
10
11
12
13

14
15

. Forma ¢ pyramidatus from the original specimen.
. A very unsymmetrical example of Forma ¢.
. A similar example more tumid in outline.

A subglobular specimen, Forma 6.

. A much elongated example of Forma 8.
. A very elevated example of Forma y.

. The plates of the apical disk.

. The interior impressions of the apical disk as seen upon a flint cast, showing the

furrow indicating the position of the base of the sand canal.
. Ambulacral and interambulacral plates from near the apex.

. Similar plates from the sides.
. Tubercles and granules of the upper surface.
. Tubercles and granules of the lower surface.

October, 1852.

EDWARD FORBES.

2

-
4
PY
+i
fal
2
oO
=
A

%

(Cretaceous )

ANANCHYTES —

Aaa goon ‘

ited 4

gic

(

®enlog

al Surbep of the Bir

ANANCHYTES (HOLASTER) SuBGLOBOSUS —_LésKe.

BRITISH FOSSILS.

DrecaDE LV. Puate VII.

ANANCHYTES (HOLASTER) SUBGLOBOSA.

-..[Genus ANANCHYTES. Lamarck. (Sub-kingdom Radiata. C\ass Echinodermata.
Order Echinoidea, Family Ananchytide.). Body orbicular, oblong, or obscurely cordate,
tumid ; with homogeneous ambulacra, convergent on the vertex, all plane, or with the an-
terior ambulacrum in a shallow furrow. No fascioles. Vent terminal, marginal or
“stpra-marginal. Apical disk elongated, and composed of four perforated genital and
five. perforated ocular plates. Tubercles perforate, their bosses crenulate. Spines
minute. No dental apparatus.
Sub-genus Hoxaster. Body cordate. Vent terminal and supra-marginal.]

Draenosis. A. ambitu subcordato; testé crassd, tumidd, lateribus
rotundatis.

Forma a. Normalis, tumida, cordata.

Forma 6. Expansa, depressa.

ANANCHYTES SPATANGIFORMIS, RormeR, Norddeutsch. Kreide Geb.,
p. 35, pl. 6, fig. 19.

Forma y. Globosa, suborbicularis.

Forma 6. Cordata, tumida, anticé sulcata.

SynonyMs.— Spatangus subglobosus, Leske ap. Kurtin, Nat. Disp.
Echin., p. 240, pl. 54, f. 2, 3. (1778.) Derranoz, Dict. Sc. Nat., vol. i,
p94. Gotpruss, Petrefacta Germanica, p. 148, pl. 45, f. 4. Dzsmouxins,
Tabl. Synopt., p. 398.

Echinus subglobosus, GMELIN.

Holaster subglobosus, AGassiZ, Prod. in Mem. Soc. d’Hist. Nat. de Neu-
chatel, p. 183. Echin. Suisses, pt. i, p. 13, pl. 2, fig. 7,9. Roxmer,
Norddeutsch. Kreide Geb., p.34. Reuss, Boehm. Kr., p. 57. Sismonpa,
Ech. Foss. Nissa., p.5. Acassiz and Drsor, Cat. Raisonné des Echinides,
Ann. des Sc. Nat., 3d ser., vol. viii. p.27. Drxon, Geol. Sussex, p. 341,
pl. 2, f. 2. and 1 and 2..

The figures given by Leske of this well-known Echinite were
sufficiently characteristic to prevent the commission of many sub-
sequent errors. Lamarck, however, applied the name to a tertiary
fossil. Since his time paleeontologists have been content to preserve
Leske’s name for this species.

[IV. vil. | AH

4 BRITISH FOSSILS.

The body varies in outline from broadly sub-cordate to sub-
orbicular, and from depressed to spheroidal. The ambulacra are
regularly radiate and linear lanceolate, the apices of the three
anterior ones converging at some small distance from those of the
two posterior ones, which meet at their tips very closely. The
breadth between the avenues of pores is nearly equal in all, but
the breadth of the double series of ambulacral plates is greater in
the lateral ones than in the odd or anterior ambulacrum. Of the
interambulacra, the hinder or odd one and the antero-laterals are
narrower than the postero-laterals. In the uppermost portion of
each ambulacrum the plates are broad and very short, and five of
them go to the breadth of an interambulacral plate; but about
half way down the sides they widen out, and near.the turn of
the base not more than two equal an interambulacral plate. In
the dorsal portion of each lateral avenue the pores of each pair”
are set well apart and connected by a furrow, but below the middle
and in the wider plates they become smaller and closer. There

are about 30 or so of the wider pairs. In the odd ambulacrum -

they are nearly similar throughout. The total number of pairs
of pores is between 35 and 50, the number in the odd ambulacrum
being less than in the others. The surfaces of the dorsal and
lateral plates of all the segments bear very minute equal primary
tubercles scattered and intermingled with minute miliary granules
on the under surface especially ; on the ambulacral segments in
the neighbourhood of the mouth the tubercles become larger. On
the anterior portion of the broadly lanceolate ventral posterior
interambulacral segment they are closely set and somewhat regu-
larly arranged, but become more scattered on its hinder part.
On the ventral ambulacral segments there are very few tubercles
but closely set granules. All the tubercles are perforated and
set upon bosses with crenulated summits. The sides are tumid
and rounded in all the varieties ; the cheeks rather swollen. There
is a shallow depression in front of the mouth terminating the more
or less marked anteal sulcus. The mouth itself is transversely
oblong ; its upper lip is higher than the lower, and thickened,
The buccal extremities of the avenues form an irregular and obscure
star around it. The anal extremity of the test is obtusely truncate,
and in the more cordate examples slightly hollowed out vertically
beneath the vent. That orifice is placed at about or a little lower
than half the height of the test. It is vertically elliptical. The
apical disk is much elongated; it is composed of four perforated

fi :
‘i a; See ee eee Se

BRITISH FOSSILS. 3

genital plates, of which that combined with the rather conspicuous
madreporiform body is largest, and of five perforated oculars, of
which the two antero-laterals are much larger than the others ; it
is the size and contiguity of these plates that chiefly cause the
elongation of the disk. The fifth or posterior genital plate is
minute and imperforate. On the cast there are traces of the pre-
sence of an internal sand-canal. The test is remarkably thick in
substance, especially beneath.

The following table of the comparative dimensions of six spe-
cimens selected on account of their differences will serve to illustrate
the variation of proportions in this species.

No. Locality. Stratum. Length. | Breadth. | Height.
1 Dover - - | Chalk Marl - 2,5, aoe 119
2 s - - | Lower Chalk - 2 9 1,3,
3 | Chaldon - | Chloritic Marl - yiz ee ee
A Beh o 5 1i2 2 12,
5 ” by = 7) ” 1 15 15
a aii ue Rees

Varieties. There is a curious variety of this species, apparently
an abnormality, in which the anterior sulcus is impressed into a
deep and almost acute furrow. I have found it at the junction of
the Chalk Marl and Upper Greensand near Abinger in Surrey,
and there is a very fine and large specimen of it in the British
Museum.

Occasionally casts in Greensand are found extremely compressed.
One of these appears to be the Spatangus Murchisoni of Konig,
Icones Sectiles, f. 169. The figure of Spatangus hemisphericus
of Phillips’ Geology of Yorkshire, pt.i, pl. 1, fig. 15, bears a close
resemblance to this species also, partially compressed. The “ Spa-
tangus argillaceus” from the Speeton Clay, of the same work, is
evidently a Holuster, and possibly this species. In cabinets
specimens of a Hemiaster from the Gault are often so labelled by
mistake.

Locality and Geological Position. This urchin abounds in the
bed of Chalk with green grains intervening between the Upper
Greensand and Chalk Marl. It is found also plentifully in the

A BRITISH FOSSILS.

Chalk Marl itself, and more rarely in the Lower Chalk. | It occurs
in all the English counties where these beds are found. It has
not been observed in Ireland.

EXPLANATION OF PLATE VIL.

Figs. 1. 2. 3. and 4. Views of an example of the normal form. The specimen selected
is from the chloritic marl of Dorsetshire.

Figs. 5. 6. 7. and 8. Outlines of different varieties from the chalk marl.

Fig. 9. The apical disk.

Fig. 10. Ambulaeral and interambulacral plates from the upper portions of their
segments.

Fig. 11. A tubercle and granules from the upper surface.

Fig. 12. A tubercle and granules from the lower surface.

EDWARD FORBES.
October, 1852.

te.

HF RON

bind

f

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es

DE CAD 4 seiner

(Cretaceous) sm

won.

ame

Do
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4

fen

9

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Surbew ot

9

ait ss eae SR A

ANANCHYTES (HOLASTER) pronuna— Lamarck.

BRITISH..EOSSILES.

DrcaApDE LY. Puate VIII.

——e

ANANCHYTES (HOLASTER) PILULA.
[Genus ANANCHYTES. Lamarck. (Sub-kingdom Radiata. Class Echinodermata.

Order Echinoidea. Family Ananchytide.) Body orbicular, oblong or obscurely cordate,

tumid, with homogeneous ambulacra convergent on the vertex, all plane or with the anterior
ambulacrum only lodged in a shallow furrow. No fascioles. Vent terminal, marginal or
supra-marginal. Apical disk elongated, and composed of four perforated genital and five
perforated ocular plates. ‘Tubercles perforate, their bosses crenulate. Spines minute.
No dental apparatus.

Subgenus Horaster. Body subcordate, vent terminal, supra-marginal. |

Disenosis. A. ambitu vix cordato; testa altd hemispherica tumida
inferne planatdé ; ano alto.

Synonyms. Ananchytes pilula, Lamarck. An. sans Vert., vol. iii. p. 27.

Spatangus prunella ? Mantevy, Geol. Sussex, p. 193, pl. 17, f. 22, 23.

Spatangus pilula, DesMou.tns, Tabl. Syn. des Echin., p. 406.

Ananchytes analis, Ronmrr, Norddeutsch. Kr. p. 35, pl. 6, f. 18.

Holaster pilula, Acassiz, Cat. Syst. p.1. AcGassiz and Drsor, Cat.
Raisonné des Echin., in Annales des Sc. Nat. 3d ser., vol. viii. p.29. Forsus,
in Dixon’s Geol. Sussex, p. 841, pl. 24. f. 10, 12 (junior).

FHlolaster coravium 2? Forsxs (not of Lamarck), in Dixon’s Geol. Sussex,
p. 342, pl. 24, f. 7-9.

Body oblong, lofty, always elevated, but not always to the same
degree, tumid above, flattened below, and with sharply angulated
sides, anteally obtuse and flattened, posteriorly abruptly truncate,
vertex slightly in front of apical disk ; posteal interambulacral area
highly arched in the dorsal region and slightly carinated, projecting
over the oblong or round vent, which is placed at a considerable
elevation, usually about half-way up the total height. Dorsal
portions of the ambulacra quite plane; in some examples the lower
part of the anteal or odd ambulacrum is slightly excavated. Plates
of the ambulacra large and broad, each equalling as much or rather
more than half the height of an interambulacral plate. In a rather
large example of this species there are 17 dorsal plates in each

[Iv. vill. | 4 I

2, BRITISH FOSSILS.

vertical row of the odd ambulacrum, about 14 and 13 respectively in
the rows of each lateral ambulacrum, and 7 in each vertical row of
each lateral interambulacrum. These plates all bear minute scattered
primary tubercles, with interspersed granules. The margins of the
plates are in some examples slightly prominent, and as if marked by
a bordering line ; more usually they are quite plane, and occasionally
shightly impressed. Beneath, the mouth is placed very near the
anteal extremity, at about or less than one fourth of the length of
the test from the margin, which in the region of the odd ambulacrum
is shghtly smuous. The two posterior ambulacra are necessarily
much longer than the others below, and proceed from near the
hinder extremity to the mouth, their course marked by a slight
depression. Their plates become elongated and polygonal, and
though thickly strewn with granules bear very few primary
tubercles. These last are more developed on the escutcheon-like
area formed by the ventral portion of the odd or posterior inter-
ambulacrum. The mouth itself is roundish or ovate, its fore lip is
depressed, its hinder lip tumid and elevated but not overlapping. —
The apical disk is with difficulty distinguished from the neigh-
bouring plates; it is much elongated, its genital and ocular pores
are minute, and the madreporiform body not very strongly marked,
On flint casts the four genital pores are usually strongly impressed,
as also are the pores of the avenues, which form homogeneous rows
indistinctly indicated, owing to their distance from each other, and
their minuteness.

The varying proportions of this species may best be illustrated
by the following comparative measurements (in inches and parts of
inches), of six specimens of slightly different bulk.

No. 1 No. 2 No. 3 No. 4 No. 5 No. 6
Height =a. Oe. 05 OL 02 ot. O11
Length - dl 0,8, 045 0 OF, 011
Breadth - 0,8, CES ee 055; 0-63 0.2, |
Height of vent
aboot margin j ong Ors Ors Ors OTs Ore

I believe there is little doubt of this pretty urchin being the
Ananchytes pilula of Lamarck, whose brief diagnosis “ A. mimuna,
“ oyato-globosa, subtus convexiuscula, ano in sunvmo margine,”

BRITISH FOSSILS. 34

is a very insufficient description. Dr. Mantell, who was the first
to notice it in England, referred it with a doubt to the Spatangus
prunella, at the suggestion of the late Mr. Konig. With the latter
fossil, however, which is a very curious species of Hemiaster well
known at Maestricht, it has no near affinity. Roemer has given a
good figure of the true type under the name of Ananchytes
analis. Its aspect and the arrangement of its ambulacral plates
are strikingly those of an Ananchytes, whilst the position of its
vent is that of an Holaster. I regard it as a link between the
groups, both being sections only of one natural genus. In some
examples of this fossil the minute granules towards the side margins
show a tendency to collect into a fasciole, a feature indicative of
an affinity with Cardiaster.

Locality and Geological Position. In the Upper Chalk of Kent,
Sussex, and other English counties.

EXPLANATION OF PLATE VITI.

Figs. 1. to 6. Various views of adult examples.

Figs. 7. and 8. Flint casts.

Fig. 9. A half grown example.

Figs. 10. to 13, young specimens.

Fig. 14. Ambulacral and interambulacral plates from the sides.
Fig. 15. The apical disk.

Fig. 16. The mouth.

Fig. 17 The vent, with its ossicles.

EDWARD FORBES.
October, 1852.

Ra
a
Pei
be ;
. ,
Fa
.
i
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te |
; as
ish
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‘

DECADE 4.PL.9.

Geological Survep of the United Mimgitom. CARDIASTER —

z ( Cretaceous ) h

O', wae ay
ee) Cian a

CARDIASTER GRANULOSUS..._ Colas.

BRITISH FOSSILS

DECADE IV. Pate IX.
CARDIASTER GRANULOSUS.

[Genus CARDIASTER. Forsezs (1850). (Sub-kingdom Radiata. Class Echinoder-
mata, Order Echinoidea. Family Ananchytide.) Body. cordate, tumid or depressed ;
lateral ambulacra having the upper part of their avenues slightly dissimilar; all the
ambulacra convergent on the vertex, the anterior one lodged in a strongly marked
sulcus with angulated sides. A fasciole passing beneath the anus and continued on the
sides. Apical disk elongated, and composed of four perforated genital and five perforated
ocular plates. ‘Tubercles perforate, their bosses crenulate. _ No dental apparatus. ]

Diagnosis. A. ambitu regulariter cordato, dorso Oe ae tuberculis
arrest dis anticis conspicuis. |
‘Synonyms. Spatangus granulosus, Gotpruss, Pet. Germ. p. 148,
a 45, fig. 3. (1826-33.) Drsmou.ins, Tabl. Syn. p. 410.

Spatangus cordiformis, icone, Geol. Norf. p. 50, pl. 5, fig. 6.
(1833. )

Holaster granulosus, AGASSIZ, Prodr. Ech. p. 16. Agassiz and Desor,
Cat. Rais, des Echin. in Ann. des Se. Nat. 3d ser. vol. viii. p. 27.

Holaster equalis, Porttocx, Geol. Rep. Londonderry, &c. p. 300" Dl 7,
a. 1): C.

Cardiaster cordiformis, Forses, Ann. Nat. Hist. 2d series, vol. vi.
p. 443.

On a recent visit to Ciply I had an opportunity of collecting the
Spatangus granulosus of Goldfuss mm situ, and recognized in it
the same EHchinite which has been noticed and figured by
Mr. Samuel Woodward, in his “ Outline of the Geology of Norfolk,”
under the name of Spatangus cordiformis. The flint casts from
the chalk of the north of Ireland, described by Colonel Portlock
under the name of Holaster equalis, and now in the collections of
the Geological Survey, evidently belong to the same species.

I constituted this genus for the species now represented and
described, and also for the curious Spatangus excentricus figured in
Woodward's work, above cited. Finding that there is a distinct
fasciole present in these urchins, and that this character is accom-
_ panied by peculiarities in the ambulacra, and, as far as I know,
invariably by the presence of a deep anteal sulcus with carinated
sides, I felt warranted in separating them generically from the
Holasters with which they had previously been associated.

The Spatangus ananchytis of Leske, quoted by Lamarck with
doubt for his Ananchytes cordata, is evidently a Cardiaster in a

[Iv. rx.] AK

2 _ BRITISH FOSSILS.

peculiar mineralized condition similar to that exhibited by examples
from cretaceous beds near Biarritz, which, judging from a specimen
communicated by Mr. Pratt, seem to be very closely allied to if
not identical with Cardiaster granulosus.

The outline of this elegant fossil is regularly cordate. In front
it is deeply furrowed by the sulcus for the odd ambulacrum, which
excavation has angulated but sloping margins. Behind it is obtusely
truncate. The general form is expanded, usually as broad as long.
The back is depressed, the apical disk nearly central, the hinder
interambulacral segment gently arched and declining, the vent
placed low, the margins of the body rounded yet somewhat com-
pressed, the base flattened yet slightly convex, the mouth close to
the anteal margin and at the extremity of the deep groove, that
terminates the odd ambulacral furrow. The test varies in degree
of convexity and expansion, but on the whole is very constant in
form. All the dorsal plates are thickly covered with minute
eranules interspersed with tubercles, the latter consisting of a
perforated knob placed on a crenulated boss, and surrounded by a

smooth areola. These tubercles are very unequal. On the anterior.

interambulacral spaces, but confined to their inner halves, are two
rows of tubercles much larger than any of the others. A similar
series of large tubercles runs -along the carinated portion of the
posterior interambulacral area, above the vent. On the under
surface the tubercles are thickly grouped and moderately large,
especially near the sides, and on the lanceolate post-oral spinous
space; but there are only granules on the two broad avenues
formed by the inferior continuations of the posteal ambulacra, or on
the central portion of the anteal ambulacrum.

In the dorsal portion of the odd ambulacrum the avenues of
pores are homogeneous throughout, the pores of each pair are placed
close together, and the pairs become more distant as the plates
become larger. There are about 28 plates visible in a well grown
example. The antero-lateral ambulacra are sub-petaloid in their
upper part, and unsymmetrical in consequence of the pores of each
pair being wider apart in the outer row than in the inner, and
moreover being united by a deeper groove. There are about 24
pairs of pores in the broader or subpetaloid portion of each series,
they are closely approximated, and those that are below widen out ;
the outer series is slightly arcuated. In the _postero-lateral
ambulacra the two series are nearly similar, and there are about
18 pairs of pores in the upper or subpetaloid portion of each series.
There are about 9 plates in each series in the dorsal portion of the

te

rh a
ia oe

BRITISH FOSSILS.

lateral interambulacral segments, and 10 above the vent in the
posterior segment. The infra-anal portion of the latter is composed
of two series of five irregularly polygonal plates each; they are
remarkable for presenting gibbosities at regular intervals. In the
inferior portions of each postero-lateral ambulacrum there are
7 plates in each series. These are polygonal, large, and elongated,
and bear the pairs of pores, which are minute and oblique, close to
their inner angles. The pores of the ambulacra around the mouth
form an obscure star.

The fasciole passes beneath the anus with a curve, and runs
along the sides just above the margin, but becomes obscure or lost
upon the anterior interambulacral segments. It is narrow, and free
from intermingled tubercles. On bad specimens it can hardly be
traced, but upon good ones is very evident.

The apical disk is covered with granules similar to those of the
neighbouring plates, so that its elements are but obscurely defined ;
it is composed of four perforated genital and five perforated ocular
plates. An imperforate genital plate is also present, but insigni-
ficant. The madreporiform body is very indistinctly marked. The
two postero-lateral genital plates are long, and cause a considerable
separation of the summits of the two hinder ambulacra from the
other three. In flint casts there are strong indications of the
presence of a sand tube like that in Ananchytes ovata.

Cardiaster granulosus grows to a considerable size. Moderately
large and evidently adult specimens in the Museum of Practical
Geology, to which they were presented by Mr. 8. P. Woodward,
measure 2 inches and -5, ths in length, the same in breadth, and
1 inch th in height. Other examples have a greater height in
proportion to the breadth, or a greater length in proportion to the
width. |

Locality and Geological Position. First observed as British by
Mr. Samuel Woodward, who recorded it (Spatangus cordiformis)
as rare in the Upper Chalk at Harford Bridge, and as common in
the ‘ Medial Chalk” at Swaffham and Thetford, all Norwich loca-
lities. The Holaster cequalis of Colonel Portlock has been already
noticed as identical with it (the original specimens have been com-
pared), and was found in the Chalk of Londonderry.

EXPLANATION OF THE PLATE.

Figs. 1. 2. 3. and 4. Different views of a Norwich specimen of Cardiaster granulosus.
Fig. 5. A flint cast ; one of the original specimens of Holaster equalis of Portlock.
Fig. 6. Ambulacral and inter-ambulacral plates from the centre of the sides.

4, BRITISH FOSSILS.

Fig. 7. A portion of the lateral fasciole, with the neighbouring surface, much
magnified.

Fig. 8. Tubercles and granules of the dorsal surface, magnified.

Fig. 9. Tubercles and granules from under surface.

Fig. 10. Large tubercles and granules of the margins of the anterior sulcus.

List oF BRITISH SPECIES OF CARDIASTER.

Cardiaster granulosus. (Described in this Decade.)
Cardiaster excentricus. (Described in this Decade.)
Cardiaster rostratus. (Described in this Decade.)
Cardiaster pygmeus, ForBEs. Ann. Nat. Hist. 2d ser., vol. vi. p. 444. (noticed only.)
c. minutus, ovatus, ambitu cordato, ambulacris tuberculisque inconspicuis,
dorso sub-carinato, ano alto.

This little species is common in the Chalk of Dover, where good specimens have
been found by Mr. C. F. Cockburn, and presented by that gentleman to the Museum
of Practical Geology. ‘The ovate outline, apparently smooth surface (under the lens
scattered primary tubercles are seen among minute granules), simple and narrow
poriferous avenues, strongly carinated anteal sulcus, subcarinated posteal segment,
and high posterior truncation with the es at the upper part, strikingly characterize
it. A middle sized specimen measures =, ths of an inch in length by -3,ths in
breadth, and —4, ths in height. Its peoaeeors vary considerably.

All the above Me iz om the White Chalk.
5. Cardiaster suborbicularis of Defrance, Brongniart, and Goldfuss (under the genus

Peso? shoo

Spatangus). This is the Holaster carinatus of Agassiz. In the Catalogue Raisonné this |

name is made synonymous with Spatangus nodulosus of Goldfuss and Spatangus planus
of Mantell, but the former appears to me to be the Holaster levis of Brongniart, and the
latter to be perfectly distinct from either.

Of Cardiaster suborbicularis I have seen only one British specimen, which on
comparison with French examples appears to be truly referable to this species. It
is from the Upper Greensand of the neighbourhood of Osmington in Dorsetshire,
where it was obtained by Mr. E.H. Bunbury, who presented it (as part of his
fine cretaceous collection) to the Museum of Practical Geology.

6. Cardiaster fossarius. The Spatangus fossarius of Miss Benett. This is the
Holaster Greenoughii of Agassiz. With us it occurs in the Upper Greensand of War-
minster.

_ 7. Cardiaster bisulcatus. In the Museum of Practical Geology theve is a Cardiaster
from the Greensand of Blackdown, remarkable for the small tubercles in proportion to its
size, and the great width of the hinder lateral poriferous avenues. It seems to be
identical with the Holaster bisulcatus described and figured by M. Albin Gras in his
“« Oursins fossiles de l’Isere,” p. 62, pl. 4, fig. 7.8. He obtained it from the Gault of Ravix,

8. Cardiaster Benstedis, sp. nov.

In the Lower Greensand of Maidstone several examples of an urchin apparently a
true Cardiaster have been found, distinct from any of our other species. It may be
characterized thus :

c. late cordatus, subhemisphericus, dorso rotundato, seriebus pororum
omnibus angustis subequalibus.

The anterior sulcus is strongly marked and wide below. The back is gently
curved. The vent is medial in position as compared with the height. The pori-
ferous avenues are all remarkably narrow, and the hinder ones as broad as the antero-
laterals. The surface of the test is too imperfectly preserved to be described.
Specimens have been presented to the Museum of Practical Geology bys Mr. E. H.
Bunbury and Mr. Morris.

October, 1852. EDWARD FORBES.

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Geologival Surbep of the Untted Ringdonr. CARDIASTER

( Cretaceous )

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Figs.1_18 CARDIASTER EXCENTRICUS _ Rose.

1S 24 -CSRDPASTER CAT DATUS 2 Farwves.

BRETISI FOSSILS,

DECADE IY. PLateE X.

ws CARDIASTER EXCENTRICUS.

FF cess CARDIASTER. Forzes (1850). (Sub-kingdom Radiafh Class Echinoder-
mata. Order Echinoidea. Family Ananchytide.) Body cordate, tumid, . .or- depressed ;
lateral ambulacra having the upper part of the avenues slightly dissimilar ; ; all the
ambulacra convergent on the vertex, the anterior one lodged in a str ongly marked sulcus
with angulated sides. A fasciole passing beneath the anus and continued on the sides.
Apical disk elongated and composed of four perforated genital and five perforated ocular
plates. Tubercles perforate, their ADEs crenulate. No dental apparatus. | —

Dracnosis. C. ambitu oe cordato, dorso elevato declivente, sulco
antico profundo sub-verticali ; vertiee valde excentrico ; extremitate anal
truncato, immunente.

Synonyms. Spatangus excentricus, Rose, in Woodward's Geology of
Norfolk, p. 27, pl. 1, f. 5. (1833.) Cardiaster excentricus, Forsprs, Ann.
Nat. Hist. 2d series, vol. vi. p. 448.

‘This singular sea-urchin is of an oblong outline, truncated behind,
deeply notched by the anteal sulcus in front, and having its widest
portion in front of the anterior third of its width. The dorsal sur-
face is very high anteriorly, the walls of the anteal sulcus rising
nearly perpendicularly to the highest part of the body immediately
in front of the apical disk. From the point of its greatest eleva-
tion the back gradually declines in a nearly straight line, forming
a long sub-carinated ridge, until it reaches the posterior truncated
extremity at about half the height of the entire body. On each
side of the centre of the back the sides fall away steeply, but the
margins of the body are rounded, and, in the antero-lateral regions,
tumid. The posterior truncation in some specimens inclines at
a gentle angle. The under surface is aa rounded and some-
what convex.

The anterior ambulacrum is lodged in a deep sulcus with sharply
angulated sides. The bottom of this furrow is rounded, and covered
with minute granules but no tubercles.) The ambulacral pores are
inconspicuous ; they become close-ranked in the upper portion.
The uppermost portion is reflected on the back with a rapid curve,
and includes about six of the vertical rows of pairs of pores. It

[Iv. x.] AL

2 BRITISH FOSSILS.

joins the apical disk a little in front of the tips of the antero-lateral
ambulacra. These are placed very far forward, and run down
upon the most tumid portion of the body. In a large specimen
as many as thirty pairs of pores may be counted in these rows,
between the apex and the margin. The avenues are at the sur-
face of the test, and the pairs of pores of their outer rows are a
very little wider than the inner ones. The postero-lateral am-
bulacra are even less conspicuous; they diverge greatly from the
antero-laterals, and form together a very acute angle. Their upper-
most portion consists of closely set pairs of pores ; on their posterior
portions the pairs of pores become very indistinct.

The plates on the margins of the anteal sulcus are thickly
studded with small primary tubercles, which are very numerous
also on the cheeks, but become few and scattered on the dorsal
surface. They are perforated, and placed on crenulated bosses.
The fasciole is distinctly marked, passing under the vent, and con-
tinued on each side even over the cheeks. The vent is large and

perpendicularly ovate, its widest diameter uppermost; the area

in which it is placed is either quite plane or slightly excavated.

On the under surface the mouth is seen near the anterior ex-
tremity, in front of the widest portion of the test; it 1s compara-
tively small and transversely oblong, the hinder lip is highest.
On the ambulacral portions of the base there are very few or no
tubercles, but a considerable number, and those rather large, on the
shield-shaped inferior portion of the odd interambulacrum. In all
the specimens that I have seen the base is much abraded. Young
examples are rather more elevated than old ones. In one of Mr. Rose’s
specimens, however, a flint cast from Swaffham, +%ths of an inch
in length, nearly the same proportions are shown as in an example
of twice the size. The most perfect specimen, in point of com-
pleteness of outline, that J have seen, measures one inch and ten-
twelfths in length, by one inch and four-twelfths in breadth.
Its anterior extremity is one inch and three-twelfths, and its
posterior nine-twelfths of an inch tn height.

Locality and Geological Position: First observed by Mr. Rose
of Swaffham, and communicated by him to Mr. Samuel Woodward,
in whose Geology of Norfolk it was briefly noticed, and slightly but
characteristically figured. It is recorded by these geologists from the
Upper and Medial Chalk of Norfolk. Mr. Bowerbank possesses a fine
flint cast showing the plates. This description is drawn up chiefly
from Mr. Rose’s original examples and Mr. Bowerbank’s specimen,
all kindly lent for the purpose, and from a fine, but imperfect,

i
7%
4

BRITISH FOSSILS. S

specimen presented to the Museum of Practical Geology by my
friend Mr. C. F. Cockburn of the Royal Artillery, who found it
in the White Chalk at Dover.

II.
CARDIASTER ROSTRATUS.

Diaenosis. C. testé lateraliter compressd, apice in rostrum elongatum
elevatumque producto.

For some time I was under the impression that this extraordinary
and anomalous little urchin of which specimens were kindly com-
municated by Mr. Bowerbank, Mr. Wetherell, and Mr. Woodward,
was the young of the Cardiaster excentricus, different as its
outline is. The series of specimens of various sizes of the latter
species shown me by Mr. Rose, (who has also found the kind now
figured,) convinces me that it is necessary to regard this beaked
and Necra-like form of Cardiaster as distinct. All the examples
are impressed with the same peculiarities. The number submitted
to me has been seven, including fragments; and in addition to
those lent for examination are two fine specimens, one of them nearly
entire, found by Mr. Cockburn in the Chalk with Flints at Bostal
Heath, near Plumstead, and generously presented by that gentleman
to the Museum of Practical Geology.

The striking feature of this form is the rhomboidal profile which
it exhibits in consequence of the obliquity of the anteal and posteal
truncations, both inclining forwards at considerable angles. The
anteal ambulacral sulcus is very deep, long, and narrow ; it rises
obliquely to a great height in consequence of the elevation of the
apical disk upon a sort of beak. The genital plates are assembled
just below its summit, which is notched by the turning over, as
_ it were, of the anteal furrow. The details of the lateral ambulacra,
in consequence of their being completely plane and very obscure,
can with difficulty be distinguished. The rostrum bends forward
slightly in its upper part. The summit of the back is more or less
sharply carinated, and declines rapidly with a faint concave curve,
until it terminates in the summit of the very oblique and rapidly
declining posterior truncation, in the uppermost part of which,
at rather less than the total height of the body, is the anus,
placed at one end of a groove. The whole of the dorsal surface
of the test is covered with granules interspersed with scattered
minute tubercles, which become more numerous on the slightly
tumid cheeks. The fasciole is strongly and distinctly marked,

4 BRITISH FOSSILS.

and passes from beneath the anus over the cheeks. The base is
flattened, and, except on the ambulacral spaces, is strongly tuber-
culated. The mouth is very small and far forward.

The largest specimen which I have seen measures ;8,ths of an
inch in length of base; 5%,ths in breadth; =3,ths in height at the
anal truncation, and when perfect must have been 12ths in height

at the anteal sulcus.
Locality and Geological Position. In the Chalk with Flints of
Kent and Norfolk.

DESCRIPTION OF THE PLATE.

CARDIASTER EXCENTRICUS. Figs. 1-18. e

Figs. 1. 2. and 3. Different views of a silicified specimen in the cabinet of Mr. Bower-
bank.

Figs. 4. 5. and 6. Outlines of a large flint cast, very perfect, in the collection of Mr. Rose.
This is the original of the figure in the Geology of Norfolk.

Fig. 7. Anterior extremity of a large specimen in which the test is preserved, in the
cabinet of Mr. Rose.

Figs. 8. 9. Half grown example, somewhat crushed, in the cabinet of Mr. Wethereil.

Figs. 10. 11. and 12. Anterior and posterior views and side profile of small specimen
in Mr. Rose’s collection.

Fig. 13. Outline of a young example in Mr. Rose’s cabinet. A flint cast.

Figs. 14. and 15. Details of the test and of the apical disk as exhibited on flint casts.

Fig. 16. Outline of the under surface.

Fig. 17. Tubercles and granules from a specimen in the Museum of Practical
Geology.

Fig. 18. Cheeks, with a part of the fasciole.

CARDIASTER ROSTRATUS. Figs. 19-24.

Figs. 19. 20. and 21. Different views of a specimen from the chalk near Plumstead,
presented by Mr. Cockburn to the Museum of Practical Geology.

Figs. 22. and 23. Outline partly restored of a large specimen from Norfolk in Mr. Rose’s
collection.

Fig. 24. Cheeks and part of fasciole.

EDWARD FORBES.
October, 1852.

MEMOIRS

OF THE

GEOLOGICAL SURVEY

OF

THE UNITED KINGDOM.

PEDLLIOw

Figures and Descriptions

BRITISH ORGANIC REMAINS.

DECADE V.

LISI

PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY.

LONDON:
PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:

PUBLISHED BY
LONGMAN, BROWN, GREEN, AND LONGMANS.
1856.

. — & with ra ¢

AOE NEB I ee ON hg OTe Leh EN ATE OL eS NAN ey Epo pti

Dis aaa
fh (y.

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BRITISH FOSSILS.

DECADE THE FIFTH.

In apologizing for the unavoidable delay which has taken place
in the publication of this Decade, owing to the much lamented
decease of Professor Edward Forbes, it is right to state that the
materials left behind by him were scanty, and had been unfor-
tunately mislaid a short time before his death. The first deserip-
tion. only, that of Solaster Moretonis, had been fully written by
him ; of the others, we had here and there notes on the distinctive
characters of the species, and of his views as to their synonymy or
history. . The plates, however, had been all engraved under his own
eye; and the specific designations under which he wished the figures
to stand, were recorded in the last edition of Morris’s Catalogue.
He had there also applied MS. names to a number of species to
be described in the Decade.

In a few cases only it has been found necessary to alter some of
these names; and this has been done in deference to an authority
which would have been gladly admitted by Professor Forbes.
To Mr. S. P. Woodward, of the British Museum, we are indebted
for all the notes respecting these supplementary species; and he
has also furnished full descriptions of three of the plates. With this
valuable aid, and the friendly communications of Dr. T. Wright, of
Cheltenham, we can present the Decade in nearly as complete a form
as it would have possessed had our friend and Master lived to finish
it. We miss, however, his lively remembrance of the living species,
and his practical acquaintance with their variations,—deficiencies
not to be supplied by reference to his published works.

[v. | 5 a 2

\

iv BRITISH FOSSILS.

Of the ten species figured three are new,—NSolaster Moreionis,
Cidaris Carteri, and Pygaster conoideus. Of the other genera,
Diadema, Echinopsis, and Hchimus present us with well-known
types from the Oolitic rocks, which are continental as well as British.
Pyrina is a rare genus in England, and in this, and the two figured
species of Pygaster, we have excellent examples of that division of
the Cussidulide in which the ambulacra are of uniform character
throughout. Several genera of this type have been figured in the
Decades. The Pygaster semisulcatus is a critical species, and its
synonymy is now for the first time cleared up. Hemiaster Mur-
chisonie is another instance of the same kind, and belongs to a
large genus of closely allied species. The Brissus Scille is a Crag
species still existing in the Mediterranean. None of these nine
genera have before appeared in the Decades.

There are engraved plates sufficient for another fasciculus, upon. -
which Professor Forbes left no memoranda, except the names of the
species. These Plates will be published at a future period.

JOHN W. SALTER,
Paleontologist.

Geological Survey Office, Jermyn Street, London,
February 1856.

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Gealogical Survev of the Unetes Kingdom. ( SOLASTER
(Oolitic)

SOLASTER MORETONIS.— ores.

BRITISH FOSSILS,

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SOLASTER MORETONIS.

[Genus SOLASTER. ‘Forbes, 1839. (Sub-kingdom Radiata. Class Echinodermata.
Order Asteriada. Family Solasteride.) Body stellate, multiradiate; covered with fasci-

“ea 4

culated spines; avenues bordered by three sets of or ‘suckers a (CROSSASTER,

Miiller.] ht a Harv, ies
| yee.

Draenosis. 8S. Fadiis i numerosis (80),, phishati lineairibus. i

REFERENCE. a ed, ap FORBES (0854), in ‘Morris's Catal. ;
2nd edit. p. 89. tied ay ‘Th vA + Six:

Very few species. of the. genus. Solaster ‘are. known i in the seas of
the passing epoch. Solaster papposus and S. endeca are both
inhabitants of the European seas. They are many rayed star-
fishes of considerable dimensions, and resemble in their shape the
conventional figure of the sun. None had hitherto been found in
the fossil state until the remarkable and unique star-fish now for
the first time figured and described was procured by Harl Ducie.
It was found in a fawn-coloured freestone belonging to the Great
Oolite (2) at Windrush Quarry, in Gloucestershire.

It differs conspicuously from its living congeners in the great
number of its rays and their linear contour. The details of its
structure are such as leave little doubt respecting its generic
position, and I do not feel warranted in constituting a new genus
for its reception. If, however, the discovery of other specimens
should show that the dorsal surface is furnished with simple and
not paxillated spines, then the foundation of a new genus might be
necessary. buat

At first glance this beautiful and well-preserved fossil seems
as if it were the head of a Crinoid, with outspread arms, crushed
flat. A nearer inspection shows that it is really a star-fish, and
suggests a close comparison between it and Uraster helianthus, a
well-known many-rayed species from the Pacific coasts of South
America. A still closer examination proves that it is not a member

Vv. 1] 5A

2 BRITISH FOSSILS,

of the family of Urasteriade, a group distinguished by the presence
of four rows of suckers in each ambulacral avenue, but belongs to
one of the genera in which there are but two rows of ambulacral
feet. The peculiar arrangement of the ossicles of the disk, which
are perfectly preserved in the specimen, the forms of the ambulacral
ossicula, the single series of interambulacral bones, the arrangement
and shape of the spines on the border of the avenues, and of the
ossicula at the basal angles of the arms, all indicate its probable
position in the genus Solaster.

The diameter of the individual figured, measured from ray point
to ray point, is somewhat more than 5 inches, the disk is 1 inch
and 5, across, and a ray is 2 inches long, and 4, of an inch
broad at its widest part. The average breadth of an ambulacrum
is =2, of an inch. There are thirty-three rays, in all of which the
ambulacral portions as well as the borders are beautifully preserved.
The extremities of some of the rays are partially turned over, but the
portion of the dorsal surface thus exposed is obscured by crushed
spines. The inner surface of the dorsal integument of the disk
occupies the centre, all the ventral portions of that region having
disappeared. The framework of the dorsal disk is for the most
part excellently preserved. The skeleton in this region is composed
of a number of rather stout and vertically compressed oblong
ossicles overlapping each other slightly, arranged in a loose and
somewhat irregularly reticular pattern. The connecting ossicula
are most perfectly seen, the spiniferous ones being partially con-
cealed by their supporters. Towards one side of the disk is a
rounded impressed space with traces of a wrinkled surface. This
I take to be the position and remains of the madreporiform
tubercle.

The position of the vent cannot be clearly traced ; a circumstance
by no means surprising, considering the difficulty there is in ob-
serving the place of this orifice in the living star-fishes.

The arms are very narrow, and of a linear shape; their- sides
being parallel throughout the greater portion of their length. At
the point of junction of the base of each arm with that of the next,
is a pair of erect semi-circular, compressed, slightly sinuous, sharp-
edged bones (the angle-ossicula). Their inner edges, 7. ¢. those
directed towards the mouth, approximate; their outer edges are
divergent. Their upper edges spread outwards, but much less so
than in the corresponding bones in the recent Solaster papposus,
and they are much more compressed and elevated. Along their
outer margin are rows of slender spines.

BRITISH FOSSILS. a

Each avenue is composed of two series of ambulacral ossicles,
about sixty in a row, their inner edges being minutely crenulated
and accurately meeting along the centro-sutural line. These ossicles
are shaped something like a dice box,* each divided into two more
expanded portions and a central narrower part. The inner portion
is flattened or slightly excavated, and somewhat rhomboidal, the
outer elevated into a ridge. The middle and more contracted
portion is carinated obliquely, and on the inner (proximal) side
has a triangular groove. <A similar groove occurs on the outer
(distal) side, placed nearer the middle than the former. The sides
of the ossicles are widely excavated for the purpose of forming the
ambulacral perforation through which the soft suckers or ambul-
acral feet passed. The interambulacral ossicles are rather quadrate,
and divided diagonally, though somewhat irregularly and lobe-like,
into two portions, of which the inner or inferior portion is elevated,
and the outer depressed. These ossicles change shape, and become
narrower as they approach the buccal regions of the ventral disk.
Their crests or elevated portions bear combs of long slender acicular
spines, with bulbous bases; of these spines there are from four to six
in each transverse row. ‘The arrangement of the dorsal surface of
the arms is too obscure in the few portions of those organs that are
reversed to enable me to make out their details with certainty ;
but 1 think I can perceive pretty clearly the paxillated character
of the spines, and that these bodies, forming the radiated or brush-
like crowns of the paxillz above described, are much shorter and
stouter than the marginal spines.

Locality and Geological Position.—in the OoLtTE of Wind-
rush Quarry, near Northleach, Gloucestershire. (Collection of Earl
Ducie.)

* They are much less bent, even near the mouth, than in the recent S. papposus.—J.W.S.

DESCRIPTION OF THE PLATE.

Fig. 1. Solaster Moretonis, natural size.

Fig. 2. Magnified ambulacral ossicles.

Fig. 3. The same, with some interambulacral ossicles magnified,—the comb-like spines
attached.

Fig. 4. Inner (proximal) portion of the ambulacrum, with its large angle-ossicula,
and their spines.

Fig. 5. Reticular pattern of the ossicles of the disk.

E. Fores (1854).
March 1856.

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DIADEMA PSEUDO-DIADEMA — Lamarck .

BRITISH FOSSILS,

DecaDE V. Puate If.

DIADEMA PSEUDODIADEMA.

[Genus DIADEMA. Gray, 1835. (Sub-kingdom Radiata. Class Echinodermata.
Order Echinida. Family Echinide.) ' Body circular, rather depressed ; ambulacral aree
with two rows of primary perforate tubercles as large, or nearly as large, as those of the
interambulacra; the latter with 2 or 4 rows of primary perforate and crenulated
tubercles ; spines long, cylindric, striated, and annulated. |

Diaenosis. D. 2-3 uncialis, hemispheri ica, depressa, tuberculis nume-
rosis regulariter radiata ; “primaris in utréque area binis, in ambulacro
minoribus (in singula serie circa 20) in spatio altero majoribus (circa 17),
secundariis parvis granulisque interpositis : disco anali parvo, rosaceo.

Synonyms. Cidarites pseudodiadema, Lamarck. (1801), Anim. sans
Vert., 1st edit. t.iii. p. 59. No.17.; 2nd edit. 1840, vol, iii. p. 385. Cidaris
monilipora, Puitures (1829), Geol.) Yorks., 1, 156. Cidaris diadema,
Youne and Brrp (1822), Geol. Survey of Yorkshire, t. 6. f. 3. Diadema
Lamarckii, Desmouins (1837), Tab. Synopt., p. 316. No. 18. (sec. Wright).
D. ambiguum, ib., p.316. (sec. Agass. and Desor). D. pseudodiadema,
Agassiz (1840), Echinod. Suisses, t. ii. p.11. tab. 17-49, 50, 52, 53.
Acassiz and DEsor (1846), Cat. Rais. des Ech., Annales des Sc., 3rd ser.
vol. vi. p. 349. Wricut (1851), Ann. Nat. Hist., vol. viii. p. 271. [t. 12.
f.1.] Corttrau (1852), Etudes sur les Ech. Foss. Yonne, p. 142. pl. 17.
fig. 1. [icon mala. |

(Diadema hemisphericum, Ac. Prodr. p..22. Cot. Ech. foss. p. 139,
tab. xvi. fig. 5-9 ?) ese hemisphericum, Drsor (1855),
Synopsis, p. 68.

Of this beautiful Oolitic ste which is not uncommon in the
Coral Rag, we have had the opportunity of figuring good specimens,
through the kindness of Dr. Wright and Professor Morris. It is an
excellent example of the genus, which has a great vertical range.
Species of Diadema are found in all the secondary and tertiary
formations, and others are still living in the Mediterranean, and in
tropical seas.

The genus, constituted by Dr. Giny for the Cidaris diadema
of Lamarck (Diad. turcarum), was formerly made by Prof. Agassiz
to include those similar and very elegant chalk species now known

[v. ii. ] 5 B

2 BRITISH FOSSILS.

by the name of Cyphosoma. None of these are yet figured in these
Decades.* They differ essentially from Diadema, by having the
tubercles imperforate, as it is called, or without a central de-
pression ; and as a character of habit may be distinguished by
having the tubercles on the ambulacral area as large as those of the
interambulacral, while in Diadema the latter are almost always of
greater size. The present genus ranges through the whole of the
secondary formations up to the present time; the Cyphosoma is
confined to the chalk formations.

The numerous species of Diadema described by Agassiz and

other authors fall, according to the Swiss naturalist, under three
groups or subgenera, the characters of which are given in the
“Catalogue Raisonné.” In the first group, of which the living
D. europeum is considered the type, the interambulacral areze
have but tvo rows of primary tubercles, without secondary rows.
Of this type, D. depressum, Ag., and D. mamillanum, Roemer, are
British fossil examples, and the majority of the species in the genus
are at present arranged in it. Of the second group the species here
figured isa good example. It has, besides the two primary rows of
tubercles, secondary rows of less size. In the third group (Tetra-
gramma), the muitiplication of the larger tubercles has proceeded
still farther, there being four rows at least on each interambulacral
space. D. Brongniartii, a cretaceous fossil, isa good British species
of the type.

Deseription.—Diameter, 2 inches 5 lines; height, 1 inch 3 lines;
diameter of the mouth (exclusive of the notches), 11 lines. General
form, subhemispheric; the upper surface depressed above, the infe-
rior surface very much flattened. From the depressed apex the
sides slope a little outwards to the rounded margin, radiated pretty
equally by the five lanceolate ambulacra, which are very little, if at
all, more prominent than the intervening spaces. They are fur-
nished with two rows of primary tubercles, about twenty in a row,
which are small near the apex, and increase in size towards the
margin, where three or four become abruptly larger ; all are per-
forate, and on crenulated bosses. Between them, for all the lower
two thirds of the ambulacrum, there is a single row of small

* A notice of some species of this genus, considered new by the late Prof. E. fate
wili be found at the end of this Decade.

+ Desor combines (in his recent work, 1855) the first and second of ac groups in
the section “ Pseudodiadema,” and he also separates those species which have the pores
crowded above (D. subangulare, Agass., — D, pentagonum), under eet fap
Diplopodia. (See Appendix.)

BRITISH FOSSILS. 3

secondary tubercles, and a few granules also are interspersed. On
the plates of the upper surface these granules surround the primaries,
but on the lower ones are only occasionally to be met with.

The primary tubercles i the interambulacral spaces are larger
than those on the ambulacra, but not quite so many in a row (about
sixteen or seventeen), and from about the upper third of the seg-
ment there are secondary tubercles, likewise perforated, but very
much smaller. There is a single row of these outside the primaries,
and a double row down the middle. ‘These secondary tubercles are
largest at the turn of the margin, and decrease rapidly in size
above or below that point. Hach plate, at least on the more pro-
minent parts of the test, bears two or three secondary tubercles on
each side of the primary one. Of these the most conspicuous are
placed on a line with the primary tubercle, the others occupy the
angles of the plates, and are interspersed with numerous granules,
which only on the upper plates surround the primary bosses. These

- bosses are of a transverse broad oval form, and for the greater part

of each row are confluent at the base. They are flat round their
base, then rise steeply to the crenulated edge, which 1s divided by
about fifteen notches, and support small strongly perforated tuber-
cles. They increase very regularly in size outwards, and radiate
regularly from the apex, instead of divaricating widely, as in the
recent D. turcarwm, and then converge rapidly on the under
surface, so as to leave a depressed space between the ambulacral
tubercles occupied by the pores. There are about seventy pairs of
pores in each row, which are disposed in a single series, and run in
nearly a straight line from the apex to the circumference ; below
this they undulate a little, and close to the oral margin about
twenty pairs fall into ranks of threes.

Each pair of pores forms an ovoid, and is included in a ring, and
an elevated tubercle or ridge separates the pores, forming as it were
a handle across the elliptical space.

The apical disk is small compared with that of other species, in
our largest specimens not half an inch across. It is composed of
five obovate genital plates, and five minute ocular plates ; the
genital plates extend outwards much beyond the oculars ; they are
covered by large granules, and are perforated nearer the outer than
the inner margin.

The right (anterior?) plate, which bears the madreporiform
tubercle, is decidedly larger than the rest. The anus is roundish,
not quite regular inshape. The mouth is larger than in our figure,
measuring, from point to point of the ten deep notches, at least

4 BRITISH FOSSILS.

three fifths of the whole diameter. The notches are placed in pairs
at the oral edge of the interambulacral spaces, their depth being
about equal to their width apart, and those of each pair are con-
siderably nearer to one another than to the neighbouring pair.

Our specimens shew no spines. They are, however, represented
by Prof. Agassiz in the Ech. Suisses, t. 17. f. 51., as slender, cylin-
drical, solid, pomted at the ends, and finely striated.

A ffinities—There seems to be no other English species with
which it can be compared, unless a somewhat more convex and
smaller form which is said to occur with it inthe Malton Oolite may
be considered distinct. This species or variety has fewer (twelve)
and rather more prominent interambulacral tubercles, and the secon-
daries between these are smaller and fewer. The ambulacra are a
trifle narrower in proportion, and are somewhat more convex than
the intervening spaces, while in the figured species there is no such
difference ; and as the primary tubercles are not so crowded in the
rows, they are rounder and less oval than in D. pseudodiadema.
The apical disk is very much the same, but there is a difference in
the arrangement of the pores near the mouth, which can scarcely
be due to age—only about eleven or twelve pairs of pores (instead
of twenty) being formed into ranks of threes. Specimens of this
in the British Museum and the Geological Survey Collections
agree with D. hemisphericum, Ag., as figured by Cotteau, and are
in all probability French specimens from the Coral Rag.

On this species Prof. E. Forbes left a good many notes, which are
embodied in the above description, and his views of the synonymy
are correctly expressed here, as also in the second edition of
Morris’s Catalogue. He has quoted in his MSS. the reference to
D. Lamarckii of Desmoulins (which Dr. Wright adopts) with a
doubt, and remarks of Cotteau’s figure, “that it represents a cast,
and is not good in its details. The pores are especially confused.
Unaccountably, teo, perhaps by the erroneous drawing of the pores
in Phillips’s figure, Cotteau has referred Hchinus germimans of
Phillips (4. perlatus of this Decade) to his species.” Agassiz and
Desor, in the Cat. Rais., have done the same, though with a mark:
of doubt. The D. ambiguum of Desmoulins, according to these
authors, is a Synonym of the present species.

Locality and Geological Position—CoraL Rac. Malton, near
Scarborough.

Foreign Localities and Range.—“ CORALLIEN” of Besancon,
canton de Soleure; St. Mihiel; La Rochelle.

J. W. SALTER.

January 1856.

BRITISH FOSSILS. 5

DESCRIPTION OF THE PLATE.

Fig. 1. Diadema pseudodiadema, Lam., from Dr. Wright’s specimen ; the apical plates
are restored from one lent by Prof. Morris.

Fig. 2. Side view of do.

Fig. 3. Part of the under surface, showing the deeply incised angles of the mouth and
the pores, a few only near to the mouth, in ranks of threes.

Fig. 4. Portion of an ambulacral and of an interambulacral segment magnified ; the
pores in simple pairs, with a tubercle between each pair.

Fig. 5. Part of an ambulacral segment near the mouth, shewing the pores in ranks of
threes, magnified. ’

Fig. 6. Apical disk, with 5 minute ocular plates, and 5 large and nearly equal ovarian
plates; the right anterior one a little the largest, and bearing the madre-
poric tubercle.

Other British Species of Diadema.

In the second edition of Morris’s Catalogue of British Fossils, Prof. Forbes had
materially increased the list of the British species of this genus. Of the new species there
recorded and referred to as described in this Decade, characters will be given, so far as the
materials permit, by our friend Mr. Woodward, In the arrangement of the species he
follows Desor, except that he regards his groups as subgeneric only.

Notes on British Fossil Diademas. By S. P. Woodward, Esq.
* JuRAssic SPECIES.

Section A. (Pseudodiadema, Desor.) Pores in single file.

1. D. pseudodiadema, Lam. Above described.
2. D. Mooret, Wright, Ann. Nat. Hist., 1854., pl. 12. f. 3.

Localities —UrrEr Las, Ilminster ; also in Normandy.

3. D. equale, Ag., Ech. Suis., t. 17. f. 36-38.

Locality—“ Cora Rae, Steeple Ashton ; M‘Coy.” Morris’s Cat. 76. The original
specimen, in the Cambridge Museum, is a fragment of D, versipora (Diplopodia) ;
another, in the Brit. Museum, appears to be the real D. equale, but its locality is
not certain.

4. D. depressum, Ag., Cat. 8. Wright, Ann. Nat. Hist, 1851, vol. viii. t. 12. £ 2.

Localities. —BraDrorD Cray, Cirencester. Great OoLirEe, Minchinhampton. In-
FERIOR OouITE, Crickley Hill and Dundry.

4a. D. armatum, Forbes, MS. Morris’s Cat., 76.

Locality INFERIOR Oo.ite, Castle Carey, (not Gloucestershire), Somerset.

Represented in the Museum of Practical Geology by four small and imperfect
specimens, undistinguishable from small examples of D. depressum.

5. D. mamillanum, Remer, Ool., vol. i. p. 26. t. 2. f.1. .D. Davidsoni, Wright ( 1854).
Ann. Nat. Hist. vol. xiii. pl. 12. fi 2.

Localities —Corat Rac, Calne (Brit. Mus.); Redcliff, near Weymouth (Geol.
Survey.)

The British specimens agree perfectly with specimens received from Dr. Remer,
labelled “ U. Coral Rag, Hildesheim, Hanover.”

lal

5B

DS

BRITISH FOSSILS.

&. Diadema homostigma, Ag. (sec. Desor), Ech. Suiss. ii. p. 24, t. 17, f. 1-5.
Locality.—CornsBrasu, Stanton, &c., Wilts (W. Buy).

7. D. vagans, Phil. sp., Geol. Yorks., t. 7. f. 1.
Locality,—CornprasH, Yorkshire. (Morris’s Cat. p. 77).

[The Cidaris Bechei, Brod. in Geol. Proc. vol.ii. p. 202 (not Geol. Tr. 2. ser. 2. t. 4.
f. 5.), from the Lias of Lyme Regis, was considered a Diadema by Prof. Forbes.
The original specimen is in the Mus. Geol. Soc. From the condition of the
specimen it would be quite indeterminable, but comparison with better examples
developed by Dr. Wright shows it to be an Echinopsis. |

8. D. Bakerie, Woodw.

Body sub-pentagonal, depressed ; lat. 16, alt. 7 lines; diameter of buccal opening 7 lines,
anal 4 lines; primary tubercles prominent, in 2 rows of about 13 each, on all the areas ;
bosses crenulated ; interspaces sparingly granulated, becoming bare above; pores in
single file.

Locality.-CoRNBRASH, Caistor, Northamptonshire. Collected by Miss Baker. (Coll.
Brit. Mus.)

[The Diadema minimum, Ag., of Morris’s Catalogue (Diadema minuta, Buckman),
is an Acrosalenia, and was first described by Quenstedt under the name of Cidarites
criniferus. |

9, D. “ subangulare,” Ag., Ech. Suisses, iv. 19. t. 17. f. 21, 22. (not of Goldfuss).
Cidaris versipora. Woodw. MS. Morris’s Cat. 1st edit. p. 50. Bronn, Index, p. 301.

Localities—Corau Rae, Calne and Hillmarton, Wilts ; Farringdon, Berks.

There are two varieties of this species ; one with the upper surface evenly inclined
ali round, the other tumid at the angles and depressed in the centre above. The
spines are like those of D. pseudodiadema. The figure given by Agassiz agrees with
a Swiss specimen in the Brit. Mus., and differs from the British examples in having
fewer and more prominent primary tubercles, especially on the ambulacral areas,
(viz. 11 instead of 13 to 16 in each row), and the ambulacral rows are not so
widely separated by a finely granulated space.

We cannot agree with M. Agassiz in considering either of these forms referable to
the “ Cidarites subangularis” of Goldfuss (Petr. 1. 122. t. 40. f. 8.) German
specimens, agreeing with Goldfuss’s figure and description in the presence of only
a single series of pores, are in the British Museum.

Section B. (Diplopodia, M‘Coy), Pores crowded above and below.
10. D. pentagonum (Diplopodia), M‘Coy, 1848, Ann. Nat. Hist. p. 412.
Locality —GREAt OoLitE, Minchinhampton. (Woodw. Mus., Brit. Mus., &c.)

In this little species the pores are crowded at the ends of the ambulacra, as in D. “ sub-
angulare ;” the character has not been considered of generic importance by
M. Agassiz or Prof. Forbes, either here or in the cretaceous and recent species,
but it has been adopted by M. Desor.

* * CRETACEOUS SPECIES.
Section A. Primary tubercles in tworows ; pores in single file. (Pseudodiadema.)

11. D. ornatum, Cidarites, Goldfuss, Petr. t. 40.f10. (Forbes, in Mus. Pract. Geol. and
Morris’s Cat. 2nd edit.) Cyphosoma Milleri, part, Forbes, in Dixon, Geol. Sussex, pp. x.
and 340, pl. 25, f. 17. (Mus. Bowerbank.)

In the first edition of Morris’s Catalogue this name was introduced, at my suggestion,
for the Warminster fossil, afterwards considered distinct and named D. Beneltie.

BRITISH FOSSILS. 7

Prof. Porbes, however, still referred to Goldfuss’s species a specimen from the
Grey Chalk of Dover, presented to the Museum of Economic Geology, by EH. H.
Bunbury, Esq., M.P.

This specimen is circular, and measures 14 lines in diameter, by 64 in height ; the
upper opening is pentangular, and 6 lines across; the mouth only 4 lines, and very
deeply sunk; the primary tubercles are more prominent than in D. Beneitie,
diminishing in size below, but not much upwards ; the areole are radiated; the
interambulacral tubercles are 12 in each row, divided by two rows of irregular
granules, separating above and leaving bare channels; these areas are bordered below
by two rows of accessory tubercles ; the ambulacral tubercles are like the others, in
two rows of 12 each, and nearly as large, converging above ; the pores are close
together above, but towards the circumference they are separated by conspicuous
tubercles, or groups of granules, which gives them a straggling appearance, and
makes them difficult of detection.

ie second example of this Diadema, presented to the British Museum by Daniel
Sharpe, Esq., has 14 tubercles in each row, and Mr. Bowerbank’s example, re-
ferred to above, has 16-17 primary tubercles, which are consequently smaller
and more crowded. A specimen in Mr. Mackie’s cabinet is more elevated, and
remarkably contracted at the base: it measures 134 lines in diameter, and 73 in
height.

Locality —Cuatx Marz, Dover. (Mus. P. Geol., Brit. Mus. &c.)

12, D. Benettie, Forbes, Morris’s Catalogue, 2nd edit. 1854. (Cidarites ornatus,
Goldf., Petr., t. 40. f. 10.2) Desor, Synopsis, p. 12.

Body circular, inflated, depressed ; lat. 14, alt. 6 lines (sp. maj.); apical disk large (154
lines diam.), pentagonal ; oral opening small (4 lines), deeply sunk; ambulacral tubercles
as large as the interambulacral, in two distinct rows of about 15 each, separated by a
double row of minute tubercles and granules; interambulacral tubercles in two primary
rows of about 14 each, separated by a wide median space, unequally granulated, which
becomes smooth above, and bordered by similar spaces, in which a few small tubercles
are developed. The areole are sometimes radiated. Pores in regular distinct rows ; those
of the circumference with a small tubercle between each pair.

This species, abundant in the Upper Green Sand of Warminster, was dedicated by
Prof. Forbes to the late Miss Etheldreda Benett, of Norton House, authoress of
the “Catalogue of Wiltshire Fossils” (1831). In the first edition of Morris’s
Catalogue it was recorded as D. ornatum, Goldf., at my suggestion ; and in the
second edition, both names appear for the one species. As we have no authentic
examples of D. ornatum, it is impossible to say in what respect it differs. M.

_ Michelin has, however, communicated to Dr. Wright a specimen labelled “ D.
ornatum, Goldf.—Cap la Héve,” which is undistinguishable from the Warminster
specimens of D. Benettia.

Localities. —UPPER GREEN Sand, Warminster; Durdle Cove, Dorset.
13. D. Barretti, Woodw.

Circular, depressed ; lat. 11, alt. 5 lines; pairs of pores in single file throughout ;
ambulacral tubercles as large as interambulacral, in 2 distinct rows of 12 each,
divided by a double row of granules margining the plates ; ¢nterambulacral tubercles
in 2 principal rows of 11-12 each, separated by 4 rows of granules, which partly
surround the tubercles of the circumference and 2 secondary rows of 8~9 rather
smaller tubercles ; base concave ; apical opening moderate, pentangular.

Differs from “ D. Benettie,’ Forbes, and from D. tenue, Ag., in the development of
secondary rows of interambulacral tubercles.

Locality.—UrrerR GREEN Sanp, Cambridge. (Coll. Brit. Mus., and of Jas. Carter,
Esq.)

8 BRITISH FOSSILS.

14. D. Bonet, Forbes, Morris’s Catal., 2nd edit. 1854.

Circular or slightly pentagonal, depressed; lat. 9, alt. 4 lines; base rather flat;
ambulacral tubercles rather prominent, as large as the interambulacral, in 2 rows of about
10 each, close together, separated only by a zigzag line of small granules ; interambulacral
tubercles also in 2 rows of 10 each, with accessory rows of about 6 small tubercles outside.
This urchin agrees with a specimen from M. Michelin, labelled (erroneously) “ D. sub-
nudum, Villers sur Mer ;” it is perhaps the D. Michelini, Desor, Synopsis, p. 72.

Locality.—This species is rather less abundant than D. Benettie in the UprER GREEN
Sanp of Warminster, and never attains an equal size. It has a more spinose appear-
ance, owing to the closer approximation of the ambulacral tubercles.

Note.—D. rotatum, Forbes, 1. ¢.,is the Cyphosoma difficile, Ag., and D. M‘Coyi, Forbes,
(D. rotulare, M‘Coy, not Ag.), does not differ from it in any respect.*

15. D. Rhodani, Ag., Ech. Suisses, t. 16. f. 16-18.
Locality“ UrpreR GREEN SAND, Blackdown, M‘Coy,” (Morris’s Catal. p. 77.)
The locality requires confirmation.

16. D. Desori, Forbes. (Syn. D. Rhodani, Ag. ?)

Circular, depressed, convex above, concave beneath ; lat. 10, alt. 4} lines; apical disk
small (lat. 34 lines), pentagonal ; ambulacra sinuous ; tubercles in two rows of 10 or 11
each in all the divisions, those of the upper surface (3 of each row) minute, with very
small bosses and areole, the interspaces minutely and uniformly granulated ; marginal
ubercles 2 or 3 in each row, large and prominent ; base with accessory rows of tubercles
on each side, and in the centre of each division; the whole small, subequal, and closely
ranged.

The solitary specimen in the Museum of the Geological Survey, upon which this
species was founded, was at first identified with D. Rhodani, Ag., but afterwards,
probably with the approval of M. Desor himself, considered distinct. Compared
with Agassiz’s figure, and with an authentic example of D. Ehodani in the Brit.
Museum, it differs in the size and form of the apical opening, and in the larger
number of smail tubercles on the upper aspect, thus giving a greater extent of
uniformly granulated surface. Several other specimens in the collections of
Mr. Cunnington and Mr. Sloper of Devizes have been examined, and show that
the species is liable to considerable variation.

Locality—Urrir Green Sanp, Warminster.

17. D. pustulatum, Forbes, 1. c.

Sub-pentagonal, depressed, concave beneath, convex above, slightly inflated at the
angles; lat. 14, alt. 6 lines ; ambulacral tubercles in 2 distinct rows of 14 or 15 each,
with 3 rows of small accessory tubercles (5 or 6 in each) below ; interambulacral tubercles
13 or 14 in each row, with 6 accessory rows of small unequal tubercles beneath ; tubercles
largest at the circumference, becoming gradually smaller above and below ; areole of
the upper tubercles very small, interspaces uniformly granulated.

This species resembles M. Agassiz’s figure of D. Rhodani even more than the last ;
compared with the specimen from the Perte du Rhone, it differs in the greater
number and regularity of the rows of tubercles, the wider space between the
ambulacral rows, the more densely granulated interspaces, and the greater number
of accessory tubercles beneath. It is to be feared that the discovery of more
specimens will not increase the validity of these differences.

Locality UPPER GREEN Sanp. (Craie chloritée), Chardstock. Presented to the
Mus. Pract. Geology by E. H. Bunbury, Esq., M.P.

* It has been placed in the genus Glypocyphus by M. Desor (Syn. p. 104), from which
it differs totally in the character of its apical disk.

a
- nd
—

BRITISH FOSSILS. 9

18. D. tumidum, Forbes, |. c.

Circular, inflated ; lat. 9, alt. 5 lines ; ambulacra straight ; tubercles numerous, small,
subequal, those of each division in 2 distinct rows; arecle small, slightly radiated ;
ambulacral tubercles separated by a double row of granules; interambulacrals bordered
by a few very small accessory tubercles ; interspaces granulated, becoming quite bare near
the apical opening. (Spines slender, solid, smooth. Coll. Bowerbank.)

Locality.—Cuatk Mart of Dover. Chlor. marl, Somerset. (Coll. Wright ; Tennant.)

The original specimen was presented to the Museum of the Geol. Survey by Edwd.
Clarke, Esq., and stated to be from the Gautt of Folkestone. It is partly incrusted
with pyrites, and filled with a matrix of what appears to be GREY CuHaLtkK,. A
better example of the same species in the Brit. Museum, undoubtedly from the
Grey Chalk of Dover, has 12 or 13 tubercles in each row.

19. D. Carteri, Woodw.

Circular, tumid ; lat. 10, alt. 6 lines ; pairs of pores in single file ; ambulacral tubercles as
large as the interambulacral at the circumference, becoming much smaller above and below,
in 2 close rows of 11 each, alternating ; interambulacral tubercles 12 in a row, separated
by a moderately wide granulated space, and flanked by rows of about 6 secondary
tubercles externally, on the under side. Base concave ; apical opening small.

Closely related to D. tumidum, Forbes. The ambulacral bosses are closer together,
and the secondary rows of interambulacral tubercles more developed.

Locality—Urrrr GreEN Sanp, Cambridge. (Coll. L. Barrett, and of Jas. Carter,
Ksqrs.

Section B. Primary interambulacral tubercles in 4 rows ; pores in double series at the
summit. (Tetragramma, Agassiz.)

20. D. variolare, Alex. Brongniart, 1834, Env. Par. p. 152. pl. M. f.9. (sec. Forbes.)
Syn. Cyphosoma Milleri, Forbes, in Dixon, Geol. Sussex, pl. 25. f. 17. (Mus.
Bowerbank.)

Localities—Specimens agreeing pretty well with M. Agassiz’s published cast occur
in the Custk Mart of Dover (Brit. Mus. and Mus. Pract. Geol.), but it is im-
possible to ascertain what species was intended by M. Brongniart’s figure and
description, without reference to the original specimen.

It is rather singular that in Morris’s Catalogue (p. 77.), we are referred for a re-
presentation of this species to Agassiz’s figure of D, Brongniarti, whilst Bronn
(Index, p, 1261.) and D’Orbigny (Prodrome, 2, p. 142.) quote Brongniart’s
figure of D. variolare in illustration of Agassiz’s D. Brongniarti. Bronn also
quotes Goldfuss’s Cidarites variolaris, which is a Cyphosoma, and D’Orbigny places
both species in the Gault.

21. D. Brongniarti, Ag., Ech. Suiss., t. 14. f. 4—6.

Localities—Grry Cuarx, Dover (Brit. Mus.). Chloritic Marl, Maiden Bradley,
Somerset (Geol. Survey). These specimens have been compared with typical
examples from the Upper Green Sand of the Perte du Rhone. In the recently
published Synopsis of M. Desor, this species is accidentally placed in the genus
“ Pseudodiadema,” amongst the species with pores in single file, whilst D, variolare
is placed in the genus Diplopodia.

22, D. Machiet, n. sp.

Inflated, depressed ; lat. 24 lines; oral opening deeply sunk, lat. 6 lines; apical opening
pentagonal, 73 lines; ambulacral pores crowded above ; primary tubercles not diminishing
sensibly above, but decreasing regularly below ; ambulacral tubercles in two rows of 17
each, at wide intervals above, the rows separated by a continuous granulated space ;
interambulacral tubercles in 6 principal rows, bordered at the circumference by accessory

10 BRITISH FOSSILS.

rows, the central space wide, granulated, and tuberculated, becoming bare and channelled
above; spines slender (less than a line wide), solid; finely striated.. A still larger
specimen, in M. Bowerbank’s cabinet, measures 24 inches across.

Locailty— GREY CHALK, Dover. (Coll. §. J. Mackie, Esq., and Bowerbank).

23. D. subnudum, Ag., Cat. Echin., p. 46. (Forbes.)

Sub-pentangular, depressed; lat. 104, alt. 4 lines ; base flat; apical opening pentangular,
its diameter 4 lines ; ambulacra straight, widening and confluent above ; the pairs of pores in
a compact double series as far as the fourteenth, a few next the mouth arranged in threes ;
primary tubercles small, subequal, those of the ambulacra in 2 close rows of 15 or 16
each, diminishing gradually from the circumference, and becoming very minute upwards ;
interambulacral tubercles in 2 principal rows of 11 or 12 each, diverging upwards, sur-
rounded by rows of granules below, and divided by a bare space above; outer rows
shorter, of 6 or 7 tubercles each.

Locality.—This species, which closely resembles the Oolitic D. subangulare, Ag.,
is one of the less common forms met with in the Upper GREEN Sanp of War-
minster; there are two specimens in the collection of Dr. Wm, Smith (Brit.
Mus.), and several in the Museum of the Geol. Survey. It is more abundant, and
attains a larger size in the chloritic marl of Somersetshire ; specimens in Dr. |
Wright’s collection measure 13 lines in diameter, and have 6 rows of interambulacral
tubercles, nearly equal in size at the circumference, like Diplopodia Koissyi, Desor.
In the collection of Dr. Wright is a specimen of this urchin from the U. Green
Sand of France, labelled “ D. variolare, Br.,” by M. Michelin.

23 a. D. dubium, Albin Gras, Oursins Foss. Suppl., p. 3. f. 21—23. (Forbes).

The specimens from Farringdon agree in their general character with a cast of the
typical D. dubium, in Dr. Wright’s cabinet, and may be identified with D. sub-
nudum, Ag., to which species M. Desor unites the D. dubium, but their state of pre-
servation does not admit of very exact compariscn.

Locality—LoweEr GREEN SanD of Farringdon, Berks. (Brit. Mus.)

24, D. Mackesoni, Forbes, |. ¢.

Sub-pentagenal, depressed, inflated at the angles; lat. 18, alt. 7 lines ; apical opening
pentagonal, lat 7 lines; ambulacra straight and rather wide, scarcely meeting above ;
pores obliquely two-ranked as far as the fourteenth pair; ambulacral tubercles divided by
2 rows of granules, and not diminishing much upwards ; interambulacral tubercles in
4 rows, the principal rows parallel, the outer rows shorter by 3 tubercles above.

Locality.—From the LowER GREEN SanpD (Kentish rag) of Hythe, presented to the
Museum of the Geol. Survey by Mr. H. B. Mackeson, Copt Pt. Folkestone. (Coll.
Mackie). It is nearly related to D. subnudum, with which, as the better preserved
species, it has been compared.

25. D. Ibbetsoni, Forbes, Morris’s Cat., p. 76.

Circular, depressed, lat. 9, alt. 34 lines ; apical opening 3, oral 34 lines across; base
tumid ; primary tubercles rather large and close-ranked, ambulacral 11-12, the 3 upper-
most minute ; interambulacral tubercles in two principal rows of 11 and 12 each, and two
external rows, shorter by 3 or 4 tubercles above, and diminishing rapidly beneath ; pores
obliquely two-ranked above, as far as the ninth pair, and again near the mouth.

This species attains a larger size, but the examples hitherto obtained are fragmentary
and obscure ; the small specimen described is very distinct from Dr. Wright's
D. Autissiodorense, which has only two rows of interambulacral tubercles, and wide
miliary zones. It is more like D. Mackesoni, but is more closely tubereulated

above.
Locality.—LowiR GREEN SAND. Atherfield, Isle of Wight. (Mus. Geol. Soc.)

BRITISH FOSSILS. ip}

26. D. Autissiodorense, Cotrmav, Cat. Meéth. (1851), p. 5. see, Wright, Ann. and
Mag. Nat. H. (1852), vol. x. p. 91.
Locality.—LowkEr GREEN Sanp, “ Cracker-rock,” Atherfield, Isle of Wight. (Coll.
Wright.)

Section C. Spines tubular, annulated. (Dradema.)

27. Diadema, sp.

This specimen consists of numerous scattered plates, with portions of the dental
apparatus, and fragments of above 100 spines. Nearly all the plates exhibit only
the smooth internal surface ; the ambulacral pores are in single file, becoming
a little crowded near the oral extremity; the interambulacral tubercles appear
to have formed more than two rows, and are of unequal size ; they are distinctly
perforated and crenulated. The spines are tubular, longitudinally striated and
annulated (as, e. g., in the recent D. calamaria) ; the annulations are often oblique,
and that nearest the articular end is very prominent. ‘These spines are cylindrical
and slender ; the largest fragment measures 15 lines, with a diameter of half a line,
and may have been 3 inches long when perfect.

_ Attention has been directed to this specimen by Mr. L. Barrett, ¥.G.S., who ascertained
that a spine from it had been inadvertently figured in pl. 10, f. 15, of Decade 3.
The figure is very bad, and the oblique annulations are described as spirals
(Micraster, Decade 3, p. 4). Several specimens, precisely similar, are in the cabinet
of Mr. Bowerbank, one of them has been figured in Dixon’s Geol. Sussex, pl. 25,
f. 8, as the spine of a Cidaris.

Locality —Urrrr Cuan, Kent. (N. T. Wetherell, Esq.)

S. P. Woopwarp.

March 1856.

3 M4
nt i) Teen ‘

}
iy

Geologicrl Surbep of the Mnited Kimgdou.

DECADE 5. PL.3.

BCHINOPSIS —
(Oolitic ) .

+

BRITISH FOSSILS.

DrcADE V. Puate III.

ECHINOPSIS ROTATA.

[Genus ECHINOPSIS. -Acassiz. (Sub-kingdom Radiata. Class Echinodermata.
Family Echinide.) Body inflated, depressed, or spheroidal ; primary tubercles in each
area small, perforated, and borne on plain, not crenulated, bosses 7 pores in single file, or
in oblique ranks of threes ; mouth but slightly notched. |

[Sub-genus Pedina, AcAss. Pores in ranks of threes. |

Diagnosis. E. sesquiuncialis, rotunda vel subpentagona, granulosa,
tuberculis primartis 10-radiatis muricata, ambulacralibus distincte binis,
parvis; interambulacrorum (in serie singula 13-14) superne majoribus
conspicuis, infra arctius aggregatis minoribus: secundariis, nonnullis ad
orem exceptis majoribus, minutis ; ore modico.

Synonyms. Pedina rotata, AGAssiz (1840), Echin. Suiss., pl. 15. fig. 4-6.
P. ornata, ib., fig. 7. [ Diadema micrococcon, Desmoutins (1837), Tabl.
Synon. des Echin., p.314.] Pedina rotata, M‘Coy (1848), Ann. Nat.
Hist. 2nd ser. vol.ii. p. 210. P. rotata, WricutT (1851), ib., vol. viii.
p- 273. LEchinopsis rotata, ForBes (1854), in Morris’s Catalogue, 2nd edit.
p. 78. [P. granulosa, Ac., Cat. Raisonné (1846), Ann. Se. Nat.,
vol. vi. p. 870. P. Gervillit, Ac., ib., 871. sec. WRIGHT. |

To the excellent description given by Dr. Wright in the eighth
volume of the Annals of Natural History, there is scarcely anything
to add; and as that author and Professor Forbes have both
abstained from citing their names, we do not feel justified in as-
sociating with this species the other very closely allied forms, viz.,
P. sublevis and P. aspera, which Prof. Agassiz had first separated
in his Echinod. Suisses, and afterwards, in the Catal. Raisonnég, united
with P. rotata. Nor would it be proper here to raise a question as
to the propriety of uniting Hchinopsis with the genus Pedina.
The essential character supposed to distinguish the latter genus, viz.,
having the bosses of the tubercles crenulated, has proved to be a

i

[v. iii] 5c

2 BRITISH FOSSILS.

mistake.* And as Prof. E. Forbes lately published, as an Hchinopsis,
a tertiary species agreeing in all the main characters with Pedina,

he has in that way distinctly recorded his opinion that the two

groups should form but one genus.

Descrvption.— Diameter, an inch and a quarter ; height, three-
quarters of an inch. “The test of this urchin is circular, but in some
specimens a fullness of the ambulacral arez gives it a slightly pen-
tagonal outline; itis particularly tumid at the circumference, and
depressed at both poles. The ambulacral areze have two rows of
small tubercles disposed along their outer border, between which
rows small granules are arranged with less regularity. The inter-
ambulacral areze are twice and a half the width of the ambulacral,
and furnished each with a double range of primary tubercles, ex-
tending from the mouth to the ovarian plates.” These primaries are
prominent, and give a rough character to the upper surface, where
they are larger and less crowded than on the lower. They radiate
in ten conspicuous rows, each pair of rows about 30° apart, and
on each side of them are very irregular secondary rows, and numerous
miliary granules, which surround the areole and cover the whole
surface. In a very good specimen, lent us by Dr. Wright, there are
thirteen plates in an interambulacral row. In the upper ones the
length is equal to the breadth, but its proportion decreases towards
the periphery, on which the plates are nearly three times as broad
as they are long (fig. 4). Each plate bears a perforated primary
tubercle, which is placed on a small smooth boss near the lower
margin, and, besides, seven or eight much smaller secondary tubercles,
perforated and surrounded by the granules. The tubercles on
the ambulacral areew are no larger than the secondaries on the
other portions. They are numerous, about thirty-three or thirty-
four in a row, perforate, and all of nearly equal size. One or two
are here and there larger than the others, but not in any regular
order. 7

“'The poriferous avenues are narrow, in which the holes are thickly
set in triple oblique pairs,” more oblique above (see fig. 4.) than on
the under surface, where the threes are so placed that the pairs
appear to be alternately 1, 2, 1, 2, the lowermost of the three coming
into line with the uppermost of the next rank, and the middle one

* In the typical group, represented by Ech. elegans, the pores are not arranged in
triple rows; and if to this be added the small size of the genital plates, (which, with the
oculars, form a sort of ring round a large anal aperture,) and the very slight indentations
of the edge of the mouth, there would seem to be good reason for separating from them
Pedina, which has triple ranks of pores, and for making the latter a sub-genus at least.

BRITISH FOSSILS. 3

standing by itself. Each pair is distinctly surrounded by an oval
ring, which disappears when the surface is abraded.

The mouth is small, and does not occupy more than a third of
the diameter, even including the short notches. These are ten in
number, and not far from equidistant; the pair beneath the am-
bulacral spaces, however, are placed closer to each other than to the
next pair: the oral margin between the notches is straight, not
rounded.

The apical disk is often well preserved, probably from its shape.
It is small, of five nearly equal heptagonal plates, the blunt points
of which form re-entering angles upon the interambulacral space,
and the madreporic plate is scarcely at all larger than the others.
Between these are five moderately large oculars of pentagonal form,
and these, as well as the genital plates, have the perforation placed
outside the middle of the plate. The anal aperture is scarcely
wider than one of the genital plates ; it 1s more angular than in our
figures. |

Affinities. —Between our British fossil and Agassiz’s description
and figure of the P. rotata there seems to be a very close similarity.
Perhaps the figure in the Ech. Suisses may represent a species with
more numerous interambulacral plates on the upper half, but it
agrees with ours in the tumid form, the shape of the ambulacral
arese, and their close-set and equal tubercles. - The latter character
we think will justify the union of P. ornata, Ag., with it, but will
at once separate P. rotata from the P. subleevis or P. aspera, Ag.,
in which only every third or fourth of these tubercles is enlarged,
so that there is a zig-zag row of conspicuous tubercles down the area,
instead of the close-set double series of small ones. Added to this,
the two Swiss species just quoted are decidedly more depressed than
P. rotata, and the secondary tubercles, instead of being scattered,
are arranged in intermediate rows on the interambulacra,

History—M. Agassiz quotes in his Catal. Rais. the name of
Diadema macrococcon of Desmoulins for this species. As that
author published his Tableau Synonymique des Echinides in 1835,*
this name would have priority, had his short description, unaccom-
panied by figure or locality, been sufficient to recognize the species.
It was well figured, but scarcely sufficiently described in the Ech.
Suisses, where the more equal character of the ambulacral tubercles
and the greater height of the test are shown in contrast with the
depressed form of P. subleevis, Ag. But in the Catalogue Rais.

* Actes de la Soc. Linn, de Bordeaux, tom, 7,

4, BRITISH FOSSILS.

the author seems to have doubted the propriety of separating these
closely allied species, and he has accordingly thrown together not
only the P. rotata and the P. ornata, in which view we think the
English specimens will bear him out, but also the more flattened
form P. aspera, from the oolites of France and Switzerland
(Oxfordien, “terrain 4 chailles”’), or, as it appears when partly
abraded, P. sublevis.

As explained above, we regard these as distinct, and in this
opinion we have the concurrence of Mr. 8. P. Woodward in support
of what appears to have been the late Prof. E. Forbes’ view. More
lately (1848) Prof. M‘Coy quoted this fossil as from the great oolite
of Minchinhampton, probably an error, as Dr. Wright has since
pointed out in the careful description above cited. We have seen
his specimen at Cambridge, and there is no doubt it is of the
Same species as ours. Lastly, in a supplementary paper (1854,
Ann. and Mag. Nat. Hist., vol. xiu.), Dr. Wright has stated that, having
examined the original specimen of Agassiz’s, P. granulosa, from the
great oolite of Ranville, he has convinced himself of their identity
with the British species. Specimens also of P. Gervillu, Ag., from
the original locality, the “ Kellovien” rock of Chaffour, Department
du Sarthe, communicated by M. Michelin and M. Lorieére, “were so
entirely like those from the Inferior Oolite of Gloucestershire, that
he would have mistaken one for the other had he not previously
marked them.” The vertical range of this species, then, even if we
do not admit its identity with P. aspera and P. sublevis, would
appear to be considerable.

Localities —INFERIOR OOLITE. In the upper beds of this forma-
tion at Shurdington Hill; Cornsprasa of Rushdon, Northampten-
shire. [Dr. WRIGHT. |

Foreign Localities—TERRAIN JURASS. des environs de Doubs,
collected by M. Renard Compte (Agassiz); GREAT OOLITE of Ran-
ville, Calvados ; OxForp CLAY, near Boulogne; KELLOVIEN of
Chauffour, Sarthe. [Dr. WRIGHT.]

DESCRIPTION OF THE PLATE.

Fig. 1. Upper surface of a very round specimen of Echinopsis rotata, natural size,
shewing the anal area and apical disk. (Coll. Geol. Surv.)

Fig. 2. Lateral view, the secondary tubercles are scarcely sufficiently evident in our
figure, which is from an abraded specimen.

BRITISH FOSSILS. 5

Fig. 3. Under side, with the small ten-notched mouth.

Fig. 3a. A part of the same magnified.

Fig. 4. A few plates from the upper side of the test, magnified. (Dr. Wright’s
specimen. )

Fig. 5, 6. A primary tubercle, with its small smooth-edged boss, surrounded by
miliary granules. 6, the same seen edgeways.

Fig. 7. The apical disk surrounding the anal space. a, perforated genital plate.
6, that one which bears the madreporiform tubercle. cc, ocular plate.

J. W. SALTER.
March 1856.

Notes on other British Species.

Prof. E, Forbes has left in MS. the following account of a large species of this genus
in William Smith’s collection, preserved in the British Museum :—

1. Ech. Smithit. Forbes, sp. nov. [Cidaris, sp. 2. of William Smith’s Strat. System, |
p. 109. }

E. biuncialis pentagona depressa, superne granulosa tuberculisque magnis bifariis late
divaricatis instructa : subtis tuberculis quadrifariis, magnis, omnibus etiam ambulacralibus
primaria fere equantibus : ore profunde inciso.

“¢ Pentangular depressed, with projecting and rather distant small mamille ; two con-
tiguous rows in each areola, and four converging rows in each area, the two
middle rows short, and only on the side or widest part of the area: rough, with
small points encircling the mamille; rays obliquely triporcus.

“*'The areole form the angles of the pentagon. The twolarger rows of mamille in
each area are parallel to the rays, and converge to the aperture, and the space
between them on the side is occupied by two shorter converging rows.

“* Locality — Tucking Mill.’

“The above is the description given by William Smith ofa fossil from the under Oolite,
to the original of which, preserved in the British Museum, my attention has been kindly
directed by Mr. Woodward. Tucking Mill is in Moreton Combe, 8.E. of Bath, and the
beds from which this urchin came probably belong to the Coral Rag.

“The specimen is a fine fragment, exhibiting two interambulacral and an ambulacral
area. The disk is broken away, but the notches of one angle of the mouth are exposed;
they are deep, and have reflected edges. The tubercles on the ambulacral area, which is
very narrow, closely alternate, aud are smaller* than those on the interambulacrals. The
inferior interambulacral plates bear, towards the periphery (and below it), two tubercles
each: the superior ones bear only one each, and that towards their outer margin. The
tubercles are deeply perforated. ‘The boss is elevated and smooth-edged, with a deeply
channeled summit, and with a distinct flattened areola at its base. The intermediate spaces
between the two rows of primaries above, and among the large tubercles on the under
surface, are occupied by very small perforated secondary tubercles with areola, and with
granules round them. ‘The diameter of the test was nearly two inches, and the height
about one inch. The pores are arranged in three ranks, and become close and crowded

below.”
E. FE.

* They are so, but on the under surface are unusually large, and to the eye appear
equally conspicuous with the primaries. This appearance has therefore been adverted to
in the diagnosis. On the upper half of the superior face they abruptly cease.—-J. W. S.

6 BRITISH. FOSSILS.

2. There is another species in the Inferior Oolite of Crickley nearly of the size of the
E. Smithii, but more convex above, and with the pores in much more oblique rows. (Dr.
Wright’s Collection.)

3. E. Bakeri. (Pedina, Wright, 1854,in Ann. Nat. Hist., vol. xiii, pl. 11. fig. 4.
Hemipedina Bakeri, ib. (1855), vol. xvi. p. 97.) an precedentis (E. Smithic) yumior ?

A small species, much resembling the Ech. Smithii. The round contour, and the
ten nearly equal distant rows of primary tubercles, will well distinguish it at pre-
sent. The pores being arranged nearly in single file on the upper portion might
be only a character derived from difference of age.

Locality—InFerior OoxireE. Crickley Hill and Leckhampton, Gloucestershire.
[Dr. Wright. ] |

One species of this section has been described from the British Tertiaries. It is—
4, E, Edwardsii, Forbes, Monog. Ech. Brit. Tert., Paleont. Soc. (1852), pl. 3. f 2.

Morris’s Catal., 2nd edit. p. 78.

A small neat species, not half an inch broad, with narrow ambulacra, which have pro-
minent tubercles except quite at the top, and crowded pores, the arrangement of
which is such that instead of falling into ranks of threes, descending obliquely from
the ambulacra outwards, they form ranks oblique in the other direction, viz.,
towards the ambulacrum. It is an unusual arrangement, and may be useful as a
specific character. From this position of the pores the avenues are broad, and
deducting these, the interambulacral spaces are not above twice as broad as the
others (‘three times,” Forbes), and the tubercles are larger, less closely placed
(about eight from the apex to the periphery), and’nearly of equal size all the way
up, while the ambulacral ones fail suddenly, and become mere granules at the
upper part. The figure in the Pal. Monograph. does not express this character
perfectly. The surface is granulated, and there are secondary tubercles as well as
granules on the interambulacra, which are only smooth down the suture.

Locality—Lonvon Cuiay. Bracklesham Bay, Sussex. (Mus. Pract. Geol.)

J.W.S.

Notes on Echinopsis, by S. P. Woodward, Esq.

In the second edition of Morris’s Catalogue, p. 78, four species of Echinopsis are
enumerated, viz. :—
E. Edwardsii, Forbes.
E, pusilla, Roemer.
E. rotata, Agassiz.
EE. Smithii, Forbes.

Of these, E. rotata and E. Smithii fall into the sub-generic division Pedina of Agassiz.
E. pusilla was erroneously referred to the group; it is probably identical with Ech. radiatus
(Heningh.), and is known in France by the name of Temnopleurus pulchellus (Sorignet,
Oursins foss. de ’Eure, p. 31). It is the type of M. Haime’s proposed new genus
Glyphocyphus (D’ Archiac and Haime’s Foss. de l’Inde, L, p. 202. Desor, Syn., p. 102.)

E. Edwardsii agrees with Pedina in the character formerly supposed to be essential,
viz., the arrangement of the pores in threes; but in his new synopsis, M. Desor places
with Echinopsis the Tertiary species (E. Gacheti), in which, as in FE. Edwardsii, the pores
are tripled.

Since the publication of Morris’s Catalogue, Dr. Wright has described no less than
fifteen additional species from the English Oolites, in which the pores are more or less in
single file. ‘To these he has given the name Hemipedina (Ann. Nat, Hist., August, 1855),
whilst M. Desor has proposed the name Diademopsis for the same group, in the second
part of his Synopsis, p. 79. Some of the species appear, too, to have heen described by
him under other names :— |

BRITISH FOSSILS. 7

Lias Species.

5. Hemipedina Bechet (Cidaris), Brod.

Locality.—Lias of Lyme Regis. (Mus. Geol. Society.)
6. H. Bowerbankii, Wr.

Locality.—Lyme Regis. (Coll. Mr. Bowerbank.)
7. H. Jardinii, Wr.

Locality.—Iminster (Mr. Moore). Bredon (Mr. Strickland).
8. H. Ettheridgii (Pedina), Wr.

Hypodiadema Etheridgii, Desor, Syn., p. 61.
Locality.—Iminster (Mr. Moore).

Inferior Oolite.

Hemipedina Bakeri, Wright. This species is a true Pedina, having the pores in
threes (see above) ; M. Desor has unfortunately placed it with Hemicidaris stramonium,
in his very ambiguous genus “ Hemidiadema,”’ Syn. Ech., p. 57.

Locality —Crickley, Dr. Wright.
9. H. perforata (Goniopygus 2), Wr.
Same locality.

10. A. tetragramma, Wr.
Same locality.

11. H. Waterhousei, Wr.
Same locality.

12. H. Bonet, Wr.
Same locality.
Great Oolite and Cornbrash.
13. H. Davidsoni, Wr.
Locality.x—Minchinhampton.

14, H. Woodwardi, Wr.
Locality.— Wilts (Dr. Wm. Smith), Dr. Wright. Marquise, near Boulogne, (Brit.
Mus.)
Coral Rag.
15. H. tuberculosa, Wr. This appears to be the Hemicidaris depressa of Ag., Cat. 9.
Locality.— Lyneham (Wm. Buy). Brit. Mus.
16. H. Marchamensis, Wr.
Locality.—Marcham, Berks. (Coll. Hon. R. Marsham.)

Kimmeridge Clay.
17. H. Morrisi, Wr.
Locality— Aylesbury. (Z. Hunt, Esq.)
18. H. Cunningtoni, Wr.
Same locality and collection

S. P. WoopwarbD.
March 1856.

DECADE 5. PLA.

Geological Surbep of the United Kingdom. | ECHINUS

( Oohtic )

Sw

ee ae

ECHINUS PERLATUS _— Des7mnarest.

C.R.Bone,del*

DRIGISHFOSSiLs,

DrcApe Vii. Puare LV.

ECHINUS PERLATUS.

[Genus ECHINUS, Linn. (Sub-kingdom Radiata. Class Echinodermata. Order
Echinide. Family Cidaride.) Body inflated ; interambulacral are composed of
numerous plates; ambulacral ares about half the width of the others, and with tubercles
of as large a size ; pores in transverse, oblique, or arched ranks of three or four pairs ;
anus covered by numerous small plates, and surrounded by five genital plates, one of
which (the left posterior, Muller) is considerably enlarged, and bears the madreporiform
tubercle. |

2 «

Diagnosis. FE. biuncialis, rotundus seu pentagonus, supra granulosus,
subtus muricato-tuberculatus; ore pentagono angulis bifidis. Tubercula
primaria conspicua, in utrdque ared bina, in singula serie ambulacri
circa 38,—interambulacri 29—secundariis supra minoribus paucis sepe
nullis, subtus maximis numerosis; granulis crebris conspicuis. Am-
bulacra vix latitudine dimidium interambulacrorum attingentia scepe
prominula. Port in series triplices parallelas—in juniore plus minusve
obliquas, collocati.

Synonyms. Knorr, Rec. des Mon. (1768), pl. E. 2. fig. 1,2. Luske
apud Kern (1778), p. 92. pl. 40. fig. 7. (nist icones ille E. gyrato potius
referenda). Echinus perlatus, DEsMaREST (1825), Dict. Sc. Nat., t. 37.
p. 100. Forsrs (1854), in Morris’s Catalogue, 2nd edit. Wricut (1851),
Ann. and Mag. N. Hist., vol. viii. 2nd ser. 274.

VAR. a, germinans, fig. 1~4.—Pentagonus conicus, in medio interambulacri
depressus, sepe levigatus ; basi subplano ; angulis oris productis ; tuberculis
secundariisinsuper paucis; ports parallelis.—E. germinans, Puituies (1835),
Geol. Yorkshire, pl. 3. fig.15. £. diademata, M‘Coy (1848), Ann. ‘Nat.
Hist., vol. ii. p. 410.

Var. f. perlatus.—Rotundus inflatus elevatus seu subdepressus, basi
subconvexo ; tuberculis secundariis numerosis magnis, granulis valde con-
spicuis ; poris in series parallelas plerumque collatis.—E. perlatus. AGASS.,
Kch. Suisses (1839), t.22. fig. 18-15. £. psammophorus, ibid., fig. 1-3.
E. lineatus, Gotpruss (1826), Petr. Germ., t. 40. fig. 11. . perlatus,

[v. iv.] 5D

2 BRITISH FOSSILS.

Agassiz and Dersor (1846), Cat. Raisonné, Ann. Sc. Nat. 8rd series,
vol. vi. p. 365. £. multigranularis, CoTTEAu (1850 ), Etudes Ech. Foss. de
V’Yonne, p. 63. tab. 7. fig. 6-8.

Var. y, serialis, fig. 5.—Depressus granulosus, tuberculis primariis ambula-
cralibus minoribus, secundartis insuper rarissimis, ad latera interambula-
crorum in serie unica dispositis ; fasctis pororum latis ; poris parallelis : basi
subconvexa; ore angulis obtusiusculis—E. serialis, Acassiz, Ech. Foss.
Suisses, |. c. fig. 10-12. Wricut, Ann. and Mag. Nat. Hist., 1. c. pl. 13.
fig. 2. Ac. and Desor, l.c. p. 366.

Var. 6, Forbesii, fig. 6.—Rotundus seu pentagonus granulosus ; tuberculis

primarius conspicuis, ambulacralibus minoribus irregularibus : fasctis poro-
rum angustis, seriebus usque ad orem valde obliquis.

At first sight it would appear very unlikely that the forms here
figured should be all of one species, or that either of them could be
identified with the much rougher and more giobose Echimus, which
Agassiz calls “sans contredit lun des plus beaux oursins connus.”

The comparison of the several English specimens, however, with
one another, and with the foreign types, convinced both Prof.
Forbes and Dr. Wright that they were identical, and as such they
have been quoted in the second edition of Morris’s Catalogue.

Agassiz has placed this fossil species and several others allied to
it with his first section of the genus, in which the pores are arranged
in triple oblique (not arched) rows, and in which the buccal mem-
brane, instead of being covered all over with calcareous plates, has
only five escutcheon-like plates disposed around the mouth. The
margin of the latter is deeply notched, and in these notches lie
those curious branched processes which Prof. Forbes counted ana-
logous to the oral tentacula of the Holothuric: (Prof. Miller terms
them ‘ tree-like gills’).

Description.—The variety germimans, forming the principal sub
ject of our plate, requires more particular notice. It is conical and
elevated above, flattened and even excavated below. Diameter of
the largest English specimen, 3 inches, its height 2 inches. The
outline, looking from above, is subpentagonal rather than rounded ;
the ambulacral ares being rather more convex than the others,
which are depressed along their median line.

The breadth of the interambulacral spaces is 24 times that of the
ambulacra at the widest part; the number of plates in a row is
twenty-nine, of which eight are basal, and, in English specimens,
bear three or four very large primary tubercles, with a few secon-
daries at the outer angles. At the turn of the margin these all
disappear, and the upper plates only bear each a single primary,

BRITISH FOSSILS. 5

of a smaller size, in the middle, flanked by a row of secondary
tubercles on the inner side, and one or two rows on the outer
margin towards the avenues. These secondary tubercles, except
the outer rows, do not, in our largest specimens, reach above half
way up the test, and these rows, on the base, are nearly equal to
the primaries in size.

The two principal rows of primary tubercles lie nearer to the
ambulacral rows than to each other; they are the only ones which
extend all the way from the apex to the base. Their tubercles are
rather closely placed, and nearly of equal size throughout, while
those of the ambulacral rows are smaller towards the apex. They
are placed upon rather sunk mammille, which are smooth-edged
above, but often present indications of the radiated muscular
markings on their outer margin. Each has surrounding it a circle
of granules of considerable size, and the entire surface of the plates
is covered pretty equally with similar granules, except above along
the median line of the interambulacra, where, for a short space, the
surface is bare.*

The ambulacra are pointed above, but parallel sided below ; the
tubercles in two rows, about thirty-eight in a row, of which ten
are basal ones ; and between these, on the lower surface only, and
in large specimens, are four or five others of equal size, in a zig-zag
row. Granules surround the tubercles, and fill up the surface as in
the interambulacral spaces ; but here and there along the sutural
line the surface is smooth. The poriferous avenues are slightly
sunk beneath the general surface, especially near the mouth. Their
breadth above is about half that of the rest of the ambulacral space,
—a little less at the turn of the margin, and then again it widens
out considerably. The pores are ranked in threes, in parallel and
but slightly oblique rows in this variety (with a row of about three
granules between each set), except near the apex, where the ranks
are much more oblique. Each pair of pores is surrounded by an oval
ring, and set obliquely, but not so much so as in our figure. There
is no tubercle or bar between the pores. The mouth is pentagonal,
with two deeply incised* notches at each angle beneath the inter-
ambulacral spaces. Between these the oral margin is rounded, but
beneath the ambulacra it is nearly a straight line. The apical disk
is well preserved ; we have figured it from both varieties; the
round variety (fig. 6), in which the ovarian plates are somewhat
more obtuse, and the var. germinans. In the latter the five genital

* This character exists to a much greater extent in the closely allied B. yyratus, Ag.

Ay BRITISH FOSSILS.

plates are heptagonal, with a broad indented base, and pierced near
their outer margin by the ovarian pore; the five oculars between
them are small pentagons pierced also near their base or outer edge.
A circle drawn round the plates of the disk would touch or nearly
touch the outer edges of all, excepting the madreporiform plate,
which is generally swelled as well as enlarged, at least in the pent-
agonal variety.

Variations.—If all the specimens on our plate be referable to
the same species, the species is a very variable one indeed. It
varies in height,—from a rotund to a pentagonal and even sub-
lobed form,—and very greatly in the degree of development of
its tubercles and of the granules of the test. These last are, in the
typical foreign examples, of considerable prominence, so much so as
partly to obscure the primary rows; while in our British examples,
though we have a few that show as many secondary tubercles, yet
these last are always smaller, and in the extreme variety (Forbesw,
fig. 6, if variety it be), the surface is pretty uniformly covered with
small granules, amongst which the rows of large tubercles are con-
spicuous, both on the interambulacral and ambulacral areas. This
kind of arrangement gives its character also to the next variety,
called EL. servalis by Agassiz; the large tubercles are not in reality
more prominent than in other varieties, but they appear so from
the want of secondary tubercles among them.

Var. Forbesit, fig. 6.—Besides the circular inflated form, in which
it resembles L. perlatus, and differs from the variety above de-
scribed, a view of the underside of this variety shows a distinction
in the mouth, which Prof. Forbes has noted in his MSS.: “ The
mouth notches are acute,” he says, “in &. perlatus (the pentagonal
form), obtuse in Z. servalis* (our figured specimen, fig. 6). Moreover,
in £. perlatus the pairs of pores are much less oblique, so that the
series become parallel on the upper surface of the test as well as
below; whereas in serialis the pores are only subparallel, beginning
from the fourth row of pores from the mouth.” This is a character
which occurs in the young of other varieties, but only near the
apex. Probably older specimens of the yar. Forbesii would have
the pores more parallel. The avenues are very little sunk either on
the upper or lower face of the test, and the interambulacral spaces
not at all indented along their middle. The arrangement of the
tubercles is much the same, as in var. germinans, but in the outer

* Prof E. Forbes regarded this variety as the E. serialis of Agassiz ; but for the
reasons assigned in the next page it is here described as var. Forbesii.

BRITISH FOSSILS. 5

interambulacral rows appear not to extend so far up, and in the
ambulacra there are fewer large tubercles developed.

Var. serialis.—We prefer to apply this name, as Dr. Wright has
done, to the depressed variety with pores in close ranks of threes,
rather than to our figure 6, which has them oblique. Agassiz’s small
figure shows close set tubercles in the ambulacral areas, and those
two rows are made greatly nearer to each other than to the inter-
ambulacral rows, while the pores are described as “no less in ranks
of threes than those of E£. perlatus.” These two characters, the
approximate ambulacral rows, and the close ranked pores, agree
with specimens from Verona in the British Museum, and with the
larger specimen described by Dr. Wright, as above quoted. This
specimen is very evenly covered with granules, and the ambulacral
tubercles, more numerous than in the typical variety or in var.
germinans, are remarkably irregular in size (see our fig. 5). Some
specimens of this variety in the Survey collections are considerably
more pentagonal than our figure, and have the ambulacral rows
wider apart, but have the surface and the pores similar.

Var. perlatus.—In the typical variety the form is much inflated,
and also moderately elevated. The avenues are broad and not sunk,
though the ambulacra project a little. The tubercles are prominent
in both areas, and surrounded by conspicuous large granules, inter-
mixed with secondary tubercles on both sides of the primaries over
a great part of the surface. These become equal in size to the
primaries on the under surface, which is therefore crowded with
large tubercles. The median line of the interambulacra is bare of
granules (but not depressed), and they are occasionally absent down
the middle of the convex ambulacra. In one fine specimen in the
British Museum, like that figured by Goldfuss as EF. lineatus, the
rows of pores are in close threes all the way up; in another, more
elevated, this arrangement alters at the upper third, and the rows
become quite as oblique as in our figures 5, 6. The base of £. per-
latus is convex, more so in depressed specimens, and the angles of
the mouth are produced. Not yet found in Britain.

There is a considerable interval between this variety and the
next, but there can be little doubt of their identity as species.

VaR. gerninans.—The differences observable among specimens
of this variety are chiefly those due to age (the young being more
depressed), and having the pores more oblique ; some of those from
the Inferior Oolite, however, are less pentagonal, and with the
‘median line of the interambulacra less depressed, and not so bare

6 BRITISH FOSSILS.

of tubercles at the upper part as those from Yorkshire, while the
granules ave also less conspicuous. Some specimens have the ambu-
lacra more prominent than others, and the avenues a little sunk.
The mouth varies in shape and in the depth of the notches. The
anus is rounder when young, and more angular in old specimens.

History—Knorr’s old figures of this fossil are tolerably charac-
teristic, and it is generally believed he intended this species.
He refers also to Klein; and in Leske’s “ Additamenta” to that
author (1778), Knorr’s figure is wretchedly copied, and made to
look like a many-lobed species.* The specimens were found with
acicular spines in connexion with them at Pfeffingen, in Basle,
from which locality Desmoulins quotes the species as one he had
not seen.

Agassiz and Desor, in the Catalogue Raisonné, refer to Desmarest
for the name. His short description, in the Dict. des Sc. Nat.,
states that his specimen had no locality, but that it was probably
from beds older than the chalk, and that others very like it were
found in the Jura. Goldfuss, in 1826, gave an excellent figure of
it, under the name of £. lineatus, showing clearly the granules in
circles round the tubercles, and also the parallel rows of pores. He
has well expressed the general rough appearance of the species,
even better than in Agassiz’s more complete figure in the Ech.
Suisses. In that work a smaller variety was figured, and called
by Agassiz FE. psammophorus, which he afterwards united with
the larger species; and also the #. serzalis, which he does not
appear to have regarded as a mere variety in his Catalogue Rai-
sonné, 1846. In the meantime Phillips had enumerated, without
a description, the variety germimans in the Geology of Yorkshire,t
which Prof. M‘Coy republished, in 1848, as E. diademata, from
the original locality. M. Cotteau’s description and figures of his
E. multigranularis are good representations of the typical EL. per-
latus ; and lastly, Dr. Wright has described a large conical variety
and a depressed one (the latter as LH. serialis) from his own neigh-
bourhood in Gloucestershire. His description rightly includes a
synonymy of the several varieties, and this has been confirmed by
the late Prof. E. Forbes, in the second edition of Morris’s Catalogue,
1854. The var. servalis and that we here term Forbesit were not
included in that synonymy, but, in accordance with the Professor's

* Unless indeed there is a general mistake in referring to that figure, which ws very
probably be intended for the -E. gyratus. See note on that species.

} “ His figure, a slight. outline, is characteristic enough, but the avenues of pores are so
indicated that the pores might be supposed to be in single file” (Forbes).

BRITISH FOSSILS. yi

own views, as shown in the arrangement of the plate, and after
carefully examining the specimens in the Museum of Practical
Geology, they are here united; the var. Yorbesi1 may, however,
eventually be regarded as a distinct species.

A ffimties.—If E. bigranularis of Agassiz (and its variety HL. vn-
termedius) be not the same species with ours, it must be closely
allied. The description of M. Cotteau would make it appear to be
a depressed variety much like serialis; it has but two rows of
primaries in each area. It occurs with the perlatus in the Great
Oolite of Grimaux, Yonne. According to M. Cotteau, #. inter-
medius of Agassiz is only a variety of bigranularis, a view in
which Dr. Wright agrees. The H£. gyratus, Agassiz, well figured
by him in his Ech. Suisses, differs at first sight materially from the
present species in the great number and small size of its tubercles,
two and even three rows being arranged outside the principal ones,
and one or two down the ambulacra. The latter are prominent,
and the avenues sunk, and the median line of the intervening areas
is bare of tubercles all the way down, and so much impressed that
the species looks lobed. It is nevertheless a most closely related
species.

Localities and Geological Range.-— UPPER? and LowER OOLitTEs.
CorAL Rac, Malton, Scarborough (Prof. Phillips’ and Brit. Museum
Collection*). Var. germinans, GREAT OoLiTz, Whitwell, Yorkshire
(Forbes). INFERIOR OOLITE, Crickley Hill, Gloucestershire (Survey
Collection) ; Leckhampton and Cleeve Hills (Survey Collection) ;
Stroud ; Nailsworth ; Minchinhampton ; Dundry (Dr. Wright).

Foreign Localities—Corau Rac (Etage Corallien), “Terrain a
Chailles,” Val de Moutiers, Ile de Ré; Salins; Besancon (Agass.
and Desor). GREAT OOLITE (Terr. Bathonien), Grimaux, Departe-
ment de l’Yonne (Cotteau). Var. serialzs, Fringeli, Canton de
Soleure (Agassiz).

* Dr. Wright has good reason for believing that this is an error of locality, and that
E. perlatus is not found in Britain above the Great Oolite.

8 BRITISH FOSSILS.

The Oolitic species of Echinus are so fully described, and also figured, by Dr. Wright,
in the paper above referred to, that it is unnecessary to do more than enumerate them ;
the first mentioned, however, has not been yet figured in any British work.

1. E. gyratus, Agass., Ech. Suisses, t. 23. f. 43-46., 1839 ; Catal. Raisonné, 1846, 1. ¢.,
p. 366.; Forbes, in Morris’s Catalogue, 2nd edit. (1854), 79. . petallatus, M‘Coy,
Ann, Nat. Hist., 1848, vol. ii. p. 409. '

E. biuncialis subconicus, pentagonus, lobatus, tuberculis numerosis—in area ambulacrali ad
basin quadrifariis, in altera seriebus sex vel octo—omnibus subequalibus ; spatio mediano
interambulacri lato lavigato ; poris subparallelis.

E. petallatus of M‘Coy is undoubtedly this species. It is a very elegant one. In all
probability Knorr’s old figure belongs to it. lLeske’s certainly represents it far
better than it does the E. perlatus.

Locality.—Corat Rac. Wiltshire (Brit. Mus.); Besangon (Agass.); Havre (Brit. Mus.).

2. E. granularis, Wrieut, Ann. and M. Nat. Hist. (1851), vol. vill. 2nd ser. p. 277.

A small species, distinguished from /. perlatus by its depressed and pentagonal
form, and its granular appearance, the latter arising from the great number of
tubercles, six or eight rows, in the interambulacral area.

Locality.—Inr. OovireE. Leckhampton Hill (Dr. Wricur).

Of the Section Arbacia. Pores in single file.
E. (Arbacia) Forbesii, Wriant, |. ¢. pl. xii. fi 4.

A small hemispheric species, with narrow convex ambulacra and interambulacral
areas, depressed and almost lobed along the median line, covered by small equal
tubercles.

Locality —Inr. OoriteE. Dundry (Dr. Wricut).

E. (Arb.) nodulosa, Wricut, |. ec. pl. xiii. f. 3.
Ech. nodulosus, Gotp¥Fuss, Pet. Germ. t. xl. f. 16.

A subpentagonal small species, covered with thick set tubercles, of larger size than
in the last. The ambulacra are prominent.

Locality — GREAT OoLitE. Sevenhampton Common, Gloucestershire.

(Dr. Wricut’s Collection, Minster’s specimen was found at Baireuth,)

EXPLANATION OF PLATE.

Fig. 1. Echinus perlatus, var. germinans ; upper side, with anal disk complete (Malton).
Cabinet of Prof. Phillips.

Fig. 2. The same; lateral view.

Fig. 3. Flattened under side, showing the pentagonal deeply-notched mouth.

Fig. 4. Outline of the large specimens of var. germinans, from the Inferior Oolite of
Crickley Hill, Cheltenham.

Fig. 42. Ambulacral and interambulacral plates of this variety, shewing the distinct
circles of granules round the bosses, the pores in parallel ranks of threes.

Fig. 4». Under side of do., showing the large secondary tubercles, and the pores in
closer and more transverse rows, with granules among them.

Fig. 4c. Anal plates of a large specimen.

Fig. 5. Ambulacral and interambulacral plates of var. serialis. The ambulacral
tubercles very irregular; magnified. Crickley Hill.

Fig. 6. Var. Forbesi, from Crickley Hill. This is evenly covered with granules, the
primary tubercles therefore are more conspicuous.

Fig. 6°. Plates and pores of do. magnified, the triple series of pores very obliquely placed.

Fig. 6». Anal plates of this variety. ‘The madreporiform plate is not greatly enlarged.

March 1856. J. W. SALTER.

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DECADE V. PLATE VY.

CIDARIS CARTERI.

[Genus CIDARIS. Krein, 1734. (Sub-kingdom Radiata. Order Echinodermata,
Family Cidaride.) Body spheroidal ; ambulacra narrow, undulating, with two or more
rows of miliary granules only ; pores in single file ; interambulacral segments very broad,
with two rows of primary tubercles, few in number, the uppermost often rudimental ;
interspaces of the areole densely granulated ; apical disk large, of 5 large genital and
5 ocular plates, round a pentagonal anal area minutely plated ; oral opening round,
simple, its disk composed of small imbricating plates. Primary spines few and large,
all the rest small and flattened. |

Diagnosis. C. parva, subconica, ambulacris bigranulatis longitudinaliter

sulcatis ; tuberculis interambulacrorum conspicuis remotis—areolis omnibus
parvis, superioribus elongatis, obsoletis.

Rererences. C. Carteri, Forses (1854), in Morris’s Catal., 2nd edit.
p. 74. Drsor (1854), Synopsis des Ech. Foss. p. 12.

Description.—Cidaris Carteri is the smallest species of the genus
found in the English chalk; the specimen represented, though
apparently adult, only measures 10 lines in diameter and 8 in
height. It is like a minature of the well-known C. scepirifera,
from which it differs chiefly in the more conical form, and in the
less development of the areolze in the uppermost plates. The
ambulacra have only two distinct and two indistinct rows of
granules, whereas the adult C. sceptrifera has four distinct and
two indistinct rows. The primary tubercles are perforated, but not
erenulated, and the areole are deeply sunk and surrounded by a
rather conspicuous circle of mamillated granules. The apical plates
are less roughly and densely granulated than in C’ sceptrifera, and
the oculars are relatively much smaller.

Locality and Geological Position.—The only specimen at present
known is in the collection of James Carter, Esq., of Cambridge,
who obtained it from the LowEr CHALK of that neighbourhood, In

a, we 5

BRITISH FOSSILS.

Morris’s Catalogue it is erroneously stated to belong to the “ Upper”
Chalk, and in Desor’s Synopsis to the “ Gres vert sup.”

EXPLANATION OF THE PLATE.
Fig. 1. Side view, natural size.
Fig. 2. Upper view, or dorsal surface.
Fig. 3. One of the interambulacral plates, and part of an ambulacrum, from the circum-
ference.
Fig. 4. Apical disk, magnified.
Fig. 5, 6. Miliary spines, magnified.

Note on some other Species of Cidaris found in British Strata.
In Professor Morris’s Catalogue three other species of Cidaris are enumerated, and
referred to the unpublished MSS. of Professor Forbes.
Cidaris confluens Inf. O., Cheltenham.
C. dissimilis, L. Ch., Kent, Sussex.
C. Gaultina, Git., Folkstone.
The characters may be given as follows :—
1, Cidaris dissimilis, Forbes, MS. Morris’s Cat., 2nd. edit. p. 74. C. sceptrifera,
Forbes in Dixon, pl. 25. f. 3.

Body small, 11 lines in diameter, 64 lines high, resembling C. sceptrifera in general
character ; ambulacra narrow, flexuous, with six ranges of small granules; inter-
ambulacral plates 4—5 ; areole circular, wide apart, surrounded by distinct secondary
tubercles; principal tubercles prominent, slightly crenulated,—the lowest minute, the
uppermost rudimentary and without areole; miliary granules large and prominent.
Spines of two sorts; the largest above, 24 lines in length, slightly swelling above the
collar (24 lines diameter), and then tapering to a fine point; collar short, striated
finely ; shaft granulated in lines; spines of lower surface very slender, 3-6 sided,
serrated at the angles; spines of areolar circles 2 lines in length, compressed and
striated.

Locality—Grery CnHatx, Dover. Collected by Messrs. Clarke, Dixon, and Taylor,
(now in Brit. Mus. and Mus. Pract. Geology).

2. Cidaris confluens, Forbes, MS. Morris’s Cat., 2nd edit. p. 74.

The specimen consists of four consecutive plates of nearly equal size, from one of the
interambulacral rows. ‘The set measures 1 inch in lengthand 4 inch wide. ‘The
areole are 4 lines wide, and broadly confluent one with another; the bosses promi-
nent and crenulated ; the lateral borders of the plates are narrow and uniformly
granulated. There are numerous fragments of spines in the same piece of rock ;
they appear to have been very long, slender, cylindrical, striated lengthwise, and
armed with a few large scattered prickles.

Locality —-INFERIoR OoxiteE. Frome (not Cheltenham).

3. Cidaris Gauliina, Forbes, MS. Morris’s Cat., 2nd edit. p. 74.

Detached plates of this species resemble those of C. vesiculosa (subvesiculosa, D’Orb.)
from the Chalk. A plate from the upper part of the test has the areola surrounded
by a circle of secondary tubercles, but not depressed. The spines are like those of
C. vesiculosa, slender, elongated, and fluted, the ridges being more finely serrated ;
the collar of the spine is shorter than in C. vesiculosa. A broken spine
accompanying the plates has the end expanded and cup-like; but in two other
perfect examples the extremities are simply contracted and truncated.

Locality—GAvLt, Folkstone. (Mus. Practical Geology. Presented by Edward
Clark, Esq.)

‘ BRITISH FOSSILS. 2

4, Ciduris velifera, Bronn. (Name only) Jahrb. 1835. p. 154. Desor, Syn. Ech, p. 34.
t. 6.f.12. C. Heberii, ib. p. 12. Syn. C. globiceps, Quenst., Petref. p. 577. t. 49. f. 17.
Of this small species there are three specimens in Mr. Cunnington’s cabinet, one of
them with six spines attached. The body measures 6 lines in diameter by 3 in
height, and is like C. clavigera of the Upper Chalk ; the spines are globular, mea-
suring only 2 lines, with a very short stalk.

Locality. UrPrer GREEN Sanp of Warminster.

5. Cidaris sceptrifera, Konig. (Dixon’s Geol. Sussex, pl. 25. f. 5, 6. best figures.)

The spine figured by M. Desor, with the name “ C. filamentosa, Ag.” Synops. Ech.
Foss. t. 5. f. 22., perfectly agrees with the typical specimens of C. sceptrifera ; that figured
as C. sceptrifera is more like a large broken spine of C. dissimilis.

6. Cidaris sulcata, Dixon, MS. Morris’s Cat. 2nd edit. p.75. Cidaris sceptrifera, var.
spinis truncatis, Forbes, in Dixon’s Geol. Sussex, p. 338. t. 25. f. 32, 33. Cidaris
vesiculosa, Miunst. (part.) Copied by Desor, Syn. Ech., pl. 5., f. 24, 25.

7. Cidaris pleracantha, Ag.? Dixon, Geol. Sussex, pl, 24. f. 23,24. What has become
of the figured spine is unknown; two rather smaller specimens are in the Dixonian
Collection, now in the British Museum.

8. Cidaris florigemma, Phil. (1829), Geol. Yorks. 1. t. 3.f.12. Park. Org. Rem. 3.

t.4.f.15. Cidaris Blumenbachit, Desor, Synopsis, p. 5 (not Munster).

This very abundant urchin has been frequently called “ C. Blumenbachii ;” Munster
having inadvertently figured its spines (and those of two others) as possibly belonging
to the test, upon which he founded his species. The real C. Blumenbachii has not
been found in England, unless the larger species obtained at Calne is to be con-
sidered a variety of it; there are fine specimens im the collection of Wm. Smith
(Brit. Mus.), and Dr. Wright. M. Desor makes C. crucifera, Ag. the “young” of
C. florigemma; but if not a distinct species it is certainly related to C. coronata and
not to C. florigemma.

Locality—Corau Rac, Calne. Wilts.

S. P. Woopwarp.
March 1856.

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BRITISH FOSSILS.

DecaDE V. Puate VI. Fig. A.

PYRINA DESMOULINSII, var. PRATTII.

[Genus PYRINA. Dexsmouttns, 1835. (Sub-kingdom Radiata. Order Echinoder-
mata. Family Cassidulide.) Body oval, tumid, flattened above and below; ambulacra
simple, continuous, radient ; mouth central inferior, elliptical; anus posterior, supra-
marginal ; tubercles perforate ; genital pores four. |

Diagnosis. PP. testd tumidd, ambitu elliptico postice leviter emarginato ;
vertice depresso; basi subconcavd ; ano in medio faciet postice excavato.

REFERENCES. Pyrina Desmoulinsii, D’ARcHIAC (1847), Mem. Soc. Geol.

(vtande 2nd ger, t.. pl. 2. p. 297., pl. 13. fig. 4.; D’Orb. Prodr...2.,

p. 78.; Agass. Cat., p.92. Pyrina Prattii, Forbes, Morris’s Catal., 2nd edit.
(1854), p. 88.

Several members of the family Cassidulidw have been already
presented in the Decades, more particularly of that division of it
which has simple, instead of petaloid ambulacra— Disaster, Galerites,
Hyboclypus. The species having this character (the Lchinoneides
of Agassiz) are abundant in the cretaceous rocks ; two out of three
sections of the genus Gulerites are quite characteristic of the Chalk
and Green Sand.

Pyrina, which differs from Galerites chiefly in its oblong instead
of circular outline, is a genus of rather small, and generally very
convex urchins. It is difficult to distinguish from it those abnormal
specimens of Galerites upon which M. Desor founded the spurious
genus Globator. Such specimens occur in the Upper Chalk of Kent,
and Upper Green Sand of Warminster, and differ from Pyrina
solely in their more circular forms.

Description.—The original example of Pyrina Desmoulinsit,
figured and described by M. le Vicomte d’Archiac, in his “ Rapport
sur les Fossiles du Tourtia,’ measures 22 mill. in length, 16 mill.
transversely, and 114 in height. The specimen now figured
measures 24 mill. long, 19 wide, 12 high, and is therefore wider,

Te eel 5 F

2 BRITISH FOSSILS.

and rather more depressed in relation to its length, than the typical
example.

These differences are equally manifest in other specimens,—one
British and three Belgian,—in the cabinets of Dr. Wright and the
British Museum. In all the foreign specimens, when viewed from
above, the outline is notched posteriorly by the vent ; in the English
specimens this is less distinctly the case, the anal opening being
rather higher up, though not so high as in the Neocomian P. pygea.

These differences are so slight, and the materials so scanty, that
it will be better to treat them as indicating varieties only of one
species.

Locality and Geological Position.—My. Pratt’s specimen, and
another in the cabinet of Dr. Wright, were obtained from the
CHALK with quartz grains at Chard, Somersetshire.

The foreign examples are from the UPPER GREEN SAND (Tourtia)

of Tournay, Belgium.

Piste Vi, Pie, 2.
PYRINA OVULUM.

Diacnosis. “P. ovata, inflata, superne depressa; ambitu elliptico, basi
plana, margine valde tumido; ore elongato obsolete decagono; facie postica
bate sulcatd ; ano elliptico, margini superiori proximo ; tuberculis numerosis.”

-—(DEsoR).

Synonyms. Nucleolites ovulum, Lamarck, Anim. sans Vert., vol. iii.
37. Goxpruss, Petr., 1. p. 138. t. xliii. f. 2. Drsmourins, Ech., p. 356.
Pyrina ov., AGAsstz (1847), Catal. Syst. Ectyp., p. 7. Dxzsor, Monogr.
des Galei, p. 26. pl. 5. fig. 35-37. ; Morris’s Catal., 2nd edit. p. 88,

Locality and Geological Position.—LowER CHALK, Dorsetshire,

(sec. Morris’s Catalogue.)

Foreign Locality— CHALK of St. Dire toon and Tours, De-
partment Indre and Loire.

EXPLANATION OF Pirate VI.
A. Pyrina Desmoulinsii, var. Prattii.

Fig, 1. Upper view of Mr, Pratt’s specimen.
Fig, 2, Side view.
Fig. 3. Under view.
Fig. 4. Posterior end.
Fig. 5. Tubercles of the upper surface, magnified.
Fig. 6 Do. and granules of the lower face.

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Fig.

BRITISH FOSSILS. 3

7. Portion of the under surface magnified, showing the triplication of the pores
near the mouth.

8. Form of the mouth, magnified.

9, Form of the vent.

10. Plates of the apical disk, magnified.

B. Pyrina ovulum, Ag.
11. Upper view.
12. Under view.
13. Side view.
14. Posterior end.
15. Tubercles and granules from the upper side, magnified.
16. Do. do, from the base,
17. Apical disk, magnified.

S. P. WooDWARD.

March 1856.

DECADE 5.) Eiitia

weologier! Surbep of the United Kingdom. PYCASTER.|
( Oolitic ) x

PYGASTER SEM@sULCcATUS _ PAP Ss.

CR.Bone, del!

BRITISH FOSSILS.

DECADE VY. Puate VII.

ene

PYCASTER SEMISULCATUS,

[Genus PYGASTER. Agassiz, 1834. (Sub-kingdom Radiata. Class Echinodere
mata. Order Echinoidea. Family Cassidulide.) Orbicular, depressed or subconic ;
ambulacra simple throughout ; tubercles perforate (and crenulate ?), disposed in very
regular series in both areas ; anus very large, superior, generally placed near to the
plates of the disk ; mouth decagonal, no tubercles round it. |

Draenosis. P. depressus, subpentagonus, margini postico subacuto, nec
truncato; tuberculis conspicuis—primariis ambulacrorum supra binis, ad
marginem in sertes 4-5—interambulacrorum 18-22—collocatis ; basi in
medio valde coneavd: ano majori lateribus tumidis.

SYNONYMS. Clypeus. semisulcatus, Puitiies (1829), Geol. Yorksh.
vol. i. p. 104. t. 3. fig. 17. (fig. two-thirds “nat. size). Buckman, in Mur-
chison’s Geology of Chelt., 2nd edit. p. 95. (1845). Nucleolites semisulc.
Desmoutins (1837), Tabl. Syn., p. 862. Pygaster semis., AGassiz, Prodr.
Kch., p. 185. Lamarox, Hist. Nat., 2nd edit. (1840), vol. iii. p. 358.
Wricut, Ann. and Mag. Nat. Hist. (1852), vol. ix. p. 89. Pygaster
umbrella, Acassiz, Ech. Suiss. (1839), tab. 13. fig. 1-3. Drsor (1842),
Monogr. des Galerites, 3., p. 77. t. 12. fig. 4-6. Fores, in Morris’s Cata-
logue, 2nd edit. 88. (not Galerites umbrella, LAMARCK).

Description.—This fine Oolitic fossil is 3 inches across in either
direction, and 14 inch in height. The general form is subhemi-
spheric, and the outline orbicular or very slightly pentagonal. The
base is flat and deeply concave at the mouth.

The upper surface is most generally evenly convex, more rarely
the sides are flattened and the shape low-pyramidal. The vertex
from which the five ambulacra radiate at nearly equal eae
is rather behind the centre, and as the large oblong anal opening *
is close to the plates of the disk, which are (always?) lost, a broad
keyhole-shaped cavity is left, which oecuencs the central and post-
central portions.

* In the young state this opening is far less conspicuous.
[v. vii. ] 5 @

24 BRITISH FOSSILS.

The ambulacra are equidistant and of equal width, scarcely one-
fourth as wide as the spaces between them. The three anterior
ones are nearly direct, while the two posterior ones are a little
bent out near their origin, to conform to the tumid edge of the
large opening ; in the ordinary varieties they are not at all elevated
above the intervening spaces. They are composed of very numerous
(about 150) pairs of plates, judging from the number of primary
tubercles—one to about three plates—and from the pairs of pores.

The primary tubercles in the ambulacral area are in four* rows
on the under surface and about halfway up the superior face, but
only the outer rows continue to the vertex. These rows are placed
along the margin close to the pores, and there are about fifty-six
tubercles in each of them, of which thirty-six belong to the upper,
and twenty-two to the under surface. They are small, perforate,
and set upon but little elevated mamille, which are sometimes
irregular or even slightly crenulate above, but often appear quite
smooth under the lens.

The surface of the ambulacral and interambulacral spaces are
occupied by small granules not very closely placed, and mixed with
a few secondary tubercies, the areole of which are distinctly sunk.
A single row of these granules separates each primary tubercle
from its neighbour, and they form rather a loose circle round each
areola.

The avenues are not sunk in any of the typical specimens, and
the pores are ranked in single file, as usual in the genus. They
are rather large, and each pair (corresponding to one of the three
plates opposite each primary tubercle) consists of an inner roundish
and an outer oval pore, the two being placed in somewhat opposite
directions, and separated by a strong elevated tubercle.

The interambulacra have numerous rows of equal-sized tubercles
similar to those of the ambulacra, with an areola distinctly de-
pressed at the margin; they are larger, at least in the principal
rows, than those of the ambulacra, and more distant, there not
being above nineteen or twenty in a complete row on the upper
surface, and fourteen or fifteen below. They are arranged in the
following manner: two complete rows down the centre of the
interambulacral plates extend from the vertex to the mouth, and on
the inner side of these—first one, then two (see 4a), and near the
margin even four, rows appear placed in regular transverse rows on
the plates. Outside the principal rows an equal or greater number

* A fifth and, rarely, even a sixth, is interposed in some specimens at the actual margin,
but net continued much above or below it.

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BRITISH FOSSILS. 3

of similar tubercles appear, but in loose order and not placed in
regular line with the rest. Altogether about twenty rows (some-
times more) may be counted at or about the margin of an interam-
bulacrum. On the under surface (fig. 3.), the transverse rows are
very distinct, and the difference between the central and the
exterior portions is particularly manifest. As the plates become
square and less transverse near the mouth, the rows become more
distant and irregular, till there are again (in the angles of the
notches) only the two primary rows left. The tubercles there are
of larger size than those represented in our fig. 3.

“The base is concave, and the mouth is central and placed in
a considerable depression. It is of moderate size, about one-
fifth the diameter of the test” in half-grown specimens, but less
in the adult. It is ten angled, the notches equally deep, but
in pairs nearer together beneath the interambulacrum than at the
avenues.

The plates of the disk are absent in all our specimens. They
appear, however, to have been depressed, From the figures given
by Agassiz of the closely allied Swiss species, the disk must have
been oblong, the two posterior lateral ovarian apertures being
placed rather wide apart, and the hinder one absent. The anal
aperture is very large, and in our specimens being confounded with
the space left by the disk plates, its shape cannot be very well
ascertained. It occupies in adult specimens full half the leneth of
the odd imterambulacrum, and appears to be oblong-oval rather
than pyriform. Its sides are incurved, but the depression in which
it lies does not extend further* than the anus itself, although the
tumid ridge on each side of it continues for some way down. In
young specimens the anal opening is very much smaller, and propor-
tionally narrow. “The spines adhering to this specimen are short,
needle shaped, and delicately striated.” (Wright, 1c.)

Variations—We have figured Dr. Wright’s very fine specimen,
which is unusually large and has the tubercles more conspicuous
than common, nor has it any convexity in the ambulacra beyond
what arises from their forming the angles of the pentagon. Other
specimens from the same locality agree with it in nearly all respects,
but have the tubercles of less size and more uumerous, twenty-four
in a row across the interambulacra, and as many as six at the

* This is one cf the many characters in which our species differs from the bad figure
of Galerites umbrella, given in the Encye. Méthodique, and which has been quoted again
and again by Agassiz as a synonym of his Pygaster umbrella, a species closely allied to
the one here described.

Ay BRITISH FOSSILS.

ambulacral margin. If this variety had a truncated posterior
margin it would be the P. Morrisw, Wright, a very closely allied
species. In others the form is slightly more pentagonal, and in
one extreme variety the form is as angular and the sides of the
pyramid as flat, as in the species next to be described (P. conoidews).
But the tubercles are large, not minute, and the ambulacra though
elevated have not sunk avenues, as in that species. The base
occasionally is not flat, but undulated, the interambulacra being
tumid on the lower surface.

The variation observable in the young state, viz., that the anal
opening is very small and narrow, has before been adverted to.
Only the two primary rows of tubercles in each area show distinctly
when the specimens are but half an inch across. |

A fiuuities—* P. semisuleatus most nearly resembles P. wm-
brella.* We have before us specimens which are well represented by
Agassiz’s figure, but the loss of the tubercles from the Swiss spe-
cimen leaves tle question of their identity an open one.” (Wright.)
And we may add, that in the Swiss species the anal opening is
larger and more pyriform, and the tumid ridge on either side of it is
absent. But it appears to be present, to judge from the profile, in
P. patelliformis, figured by Agassiz in the same plate (Hch. Suisses,
tab. 13, f£ 1-3.), a species in which we can scarcely see any character
which should sufficiently separate it from P. semisulcatus, unless
it be the breadth of the ambulacra and the continuation of their
inner rows of tubercles higher up than in ours. The anus is cer-
tainly larger and seems to be pyriform rather than oval-oblong.
This last difference may be sufficient to distinguish the two species,
and it is accordingly inserted in the specific character. P. laganoides,
Agass., figured in the same work, and in Desor’s Monograph, is even
more like, especially in the form of the anus, which is also placed
in a depression along with the plates of the disk. The greater
- breadth of the ambulacra, the larger size of the mouth, and the
much closer and more regularly placed tubercles, however, prevent
us from uniting it with ours. P. tenuis of Desor’s Monograph,
tab. 12. f. 1-3., is so very like in the arrangement of the tubercles,
narrow ambulacra, and sunk mouth, that but for the more depressed
shape and large anal opening, which too, is not flanked by tumid
ridges, it might be identical. It is from the Jura, in the “Terrain
& Chailles.”

History.—The list of synonyms was all that was left regarding
this species by Professor Forbes, and in deference to him the

* Now P. dilatatus, Ag., Cat. Raisonné, 1. c., p. 144.

BRITISH FOSSILS. 5

refere1ice to Galerites umbrella of Lamarck would have been re-
tained, but that there is evidently a mistake altogether about that
species, which is a Nucleolites, and not a Pygaster; and the
quoting of it at all by Agassiz was probably an accidental error,
which has been copied by himself and others without looking to
the original figure of Klein.* | Lamarck’s description indeed might
probably be mistaken for that of a Pygaster, as he distinctly says
“sulcis ambulacrorum angustis biporosis,” but he adds, “ sub-
striatis,” and the figure shows broad avenues with the pores con-
nected by transverse furrows ; in fact, it is much like some forms
of the common Nucleolites (Clypeus) patella, though probably a
distinct species.

Prof. Buckman’s notice, in 1845, of Clypeus ornatus, from the
Oolite of Cheltenham, recalls the general form and markings of the
species, though his specimen, as usual, having lost the plates of the
disk, he makes a mistake in supposing the anal opening to have
been at the vertex, the broad sinus extending from it halfway
downwards being the aperture in question.

“The figure given by Phillips in 1829 without a description is a
mere outline, two-thirds the natural size, without details of struc-
ture, but sufficiently like for identification. It is said, at p. 104, to
be common to the Coralline Oolite and Cale. Grit, in Yorkshire
and Oxfordshire.’—(Forbes.) Phillips’ species was admitted by
Desmoulins in his Catalogue of Echinoderms, and considered by
him a Nuecleolites. Agassiz, in his Prodromus, placed it in the
genus Pygaster, under which name it has been included in the new
edition of Lamarck (1840), and in Desor’s ‘ Monograph of the
-Galerites’ (1842). The latter author considered it (p. 76, 77) as
probably the young state of the P. wmbrella, not being aware that
Phillips’ figures were so much reduced. But he, strangely enough,
quotes with it as synonyms of the P. wmbrella, the old references
given by Lamarck to the figures in the Encyclopédie, and those
of Plott, Klein, and Leske, while he takes some pains in the text
to show how wrongly it has been arranged as a Nucleolites by
the side of the WV. patella. This confusion has only been partly
remedied by himself and Agassiz in the Cat. Raissonné, the reference

* Tt is remarkable that Agassiz should have repeated this mistake in rectifying the
synonyms of Pygaster in the Catal. Raisonné. Klein’s figure of Clypeus sinuatus, from a
specimen in the Dresden Museum, is better than the copy in the Encyc. Méthod., and
shows the broad avenues more plainly. Leske compares it with the common English
Nucleolites, which he calls C. Plottiz, and says it has a more depressed form. They are
apparently different species.

6 BRITISH FOSSILS.

to Galerites umbrella still being retained for a French species
of Pygaster, while the P. umbrella of the Ech. Suisses is altered
to P. dilatatus. No mention is made of the P. semisulcatus of
Phillips.

Dr. Wright, Annals Nat. Hist. for 1852, gave the first real des-
cription of the British species, distinguishing it carefully from the
two other British forms, while with good reason expressing doubts
as to its identity with the Swiss species, of which only a cast was
published. In Morris’s Catalogue, second edition, Professor E. Forbes
adopted the present name, quoting Agassiz’s P. wmbrella only as a
synonym. This course we are bound to follow in this Decade, for
even if Agassiz’s species should prove identical, it will be necessary
to keep Phillips’ name, since the old reference to Lamarck is un-
doubtedly erroneous.

Locality and Range—GrkEAt Oo.itEe, Minchinhampton, Glou-
cestershire (Dr. Wright); Whitwell, Yorkshire, (in Catc. Grit
Phillips), but probably, “Great OoLiTE” (Dr. Wright). See note at
end of next description. INFERIOR OOLITE, Crickley Hill and Chel-
tenham, in the “ Pea Grit,” (Id. and Coll. Geol. Survey.)

ForeEIGN DistriputicN—doubtful. If P. patelliformis (P. wm-
brella of Agassiz) be identical, it occurs in the Kimmeridge Clay of
the Jura Soleurois.

EXPLANATION OF PLATE VII.

Fig. 1. A fine specimen full grown, from the Inf. Oolite, Cheltenham, (Dr. Wright).

Fig. 2. Posterior view of do., showing the four rows of ambulacral tubercles towards
the margin.

8. Part of under side.

Fig. 4. Plates and avenues, with pores in single file.

5, 6. Primary and secondary ambulacral tubercles, with the usual number of

pores opposite to them. ‘The pairs of pores are somewhat divergent.

Fig. 7. Interambulacral tubercle, with its surrounding granules.

Fig. 8. Side view of the same. The area is scarcely sunk enough round the margin,

in this figure,

J. W. SALTER,
March 1856.

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DECADE 5. Ph.

PYCASTE
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BRITISH. £OSSILLS.

DrecaDE V. Puate VIII.

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PYGASTER CONOIDEUS.

[Genus PYGASTER. Acassiz (1834.) (Sub-kingdom Radiata. Class Echinoder-
mata. Order Echinoidea. Family Cassidulide.) Orbicular, depressed or sub-conic ;
ambulacra simple throughout; tubercles perforate (and. crenulate ?), disposed in very
regular series in both areas ; anus very large, superior, generally placed near the plates
of the disk ; mouth decagonal, no tubercles round it; a }

Diaenosis. P. pyramidalis pentaedrus, margini Me postee subacuto ; tuber-
culis minutis et ut sparsis, subtus majoribus et crebris; ambulacris elevatis,
angustis: ano modico, nec dimidium interambulacri planati efficiente.

Synonyms. Pygaster conoideus, Wricut, Ann. and Mag. Nat. Hist.
(1852), cee IX. p. 91. pl. 3. fig. 1.

The aly cabinet that appears to contain this well-marked species
is that of our friend Dr. Wright, who has lent it us for figuring.
We may expect soon a full account from him, and of other British
species not here mentioned, in the volumes of the Paleeontographical
Society.

It is more conoidal than any of oe genus, the anterior and lateral
surfaces forming angles of from 50° to 55° with the base, and the
posterior side an angle of about 42°. Its height is an inch and -3,,
and its diameter nearly 24 inches either way (Wright). The base
is nearly flat so far as it can be seen. The ambulacra are narrow
and prominent, and are placed at equal distances, each being less
than one fourth the width of the intervening spaces. The three
anterior radiate in straight lines from the depressed disk, which is
lost in our specimen ; the two posterior curve first outwards to
avoid the edges of the anal BRonNg, and then proceed straight to
the margin. Eh ees

[v. vii. | 5 H

bg

BRITISH FOSSILS.

The primary tubercles on the ambulacra are arranged in two
rows along the margin, and are small and inconspicuous; there are
about thirty-two on the upper face. Between these are two other
rows, less regular, but reaching halfway up, or sometimes further,
and near the margin one or even two rows are introduced within
these. On the under side the tubercles increase much in size, and
are in four regular rows. The areole are very flat and depressed
round their margin, which is often faintly radiated ; there is no
appearance of crenulation on their upper edge. The boss is small
and bead-like, and shows the perforation well. There is a circle of
granules round each areola, and scattered equal-sized granules,
without any secondary tubercles between, over the surface.

The avenues are narrow and rather sunk, the pores in very
regular single file (not at all undulated as in P. semisulcatus.)
Each pair consists of a transverse and an oblique one, not differing
much in size, and separated by a small prominent ridge, not a
tubercle. There are about three ambulacral plates to each primary
tubercle, so that there are nearly ninety plates in a series on the
upper face. The pairs of pores are a little more distant below.

The interambulacral tubercles are like the others in size on the
upper and lower faces ; and their arrangement is very similar to
that in the last-described species, viz., in transverse rows on the
inner half of each ambulacral plate, and in scattered order on the
outer portion, where they are decidedly larger, and, as our fig. 5
shows, often irregular ; and sometimes they are absent. On the
marginal plates there are often five tubercles in a row on the inner
half, and three double rows on the outer, but above they are much
fewer and less regular. About seventeen plates occur in:an inter-
ambulacral series, much bent in outline, as shown in figure 5. The
primary row (a) of tubercles occupies the median angle as usual.

The tubercles on the under surface are too wide apart in our
fioure. They are in irregular transverse rows, and their smooth
depressed areolz in some parts nearly touch, leaving room only for
the granules between. We can see no trace of crenulation on the
edges.

A ffimties.—Except with the pyramidal variety of P. senisuleatus,
before noticed, there js no species with which this can be compared.
The small regular tubercles well distinguish it from that, and,
together with the elevated ambulacra, seem to afford a good specific
character. They are raised not only in the middle, but from their
edges, and the avenues consequently sunk in a shallow groove.

BRITISH FOSSILS. 3

History.— Described by Dr. Wright in the paper above quoted,
and admitted into Morris’s Catalogue, 2nd edit. by Prof. E. Forbes.
He left no notes upon the species.

Locality and Geographical Position.—IN¥. OoLITE, in the pea-
grit of Crickley Hill, north of Cheltenham. Mr. Lycett’s specimen
came from the INF. OOLITE, near Stroud. (Dr. Wright.)

J. W. SALTER.

EXPLANATION OF PLATE VIII.

Fig. 1. Dr. Wright’s specimen from Crickley Hill. Upper side; the disk plates lost,
and the space occupied by them confused with the anal opening.

Fig. 2. Under side of do. only partly relieved from the stone.

Fig. 3. Posterior view, showing the height of the test.

Fig. 4. Lateral view, left side.

Fig. 5. Plates and avenues, with tubercles and granules.

Fig. 6. A tubercle from the interambulacral area, upper surface.

Fig. 7. Do. from the under side.

Other British Species of Pygaster.

As Dr. Wright will give a full description of this genus in his volume on the Echino-
dermata (Paleont. Soc. Trans.), it will be only necessary to notice the other British
species very briefly. He has furnished us with the following memoranda:—

2. “ Pygaster Morrisii, Wright, Annals and Mag.of Nat. Hist. vol. 9. 2nd series, pl. iv. fig 1.

“ Test pentagonal depressed; marginal fold very tumid; single interambulacrum much
truncated; ambulacral areas wide, convex, and prominent, with six rows of tubercles;
interambulacra wide, with the tubercles in regular rows, from 20 to 22 rows at the
equator; base depressed towards the mouth opening, which is small; anal opening large,
occupying two-thirds of the dorsal portion of the single interambulacrum.

“ Locality.—CornBRASH, near Stanton, Wilts. (Dr. Wright.)

“3. Pygaster umbrella, Agassiz, Descript. Echinoder m. Foss, de la Suisse. part 1. p. 83.
tab. xili. fig. 4.

“Test large, very pentagonal, more or less elevated; ambulacral areas narrow, with two
marginal rows of tubercles throughout, and ‘two inner rows which commence at some
distance from the peristome and extend only a short way above the marginal fold;
interambulacral areas wide, with from 16—18 rows of tubercles at the equator; the
tubercles are arranged in threes obliquely across the plates, and thus produce irregular
rows; the anal opening is distinctly pyriform, occupying rather more than one-half the
length of the dorsal surface of the single interambulacrum ; base concave; mouth opening
small; peristome decagonal, equal-lobed; tubercles on the base, larger, and more regularly
arranged, than those on the upper surface.

“ Localities. —-CorALiInE Ooxitsx, Calne, Farringdon, Malton; specimens from each
of these localities are in the collection of Dr. Wright.

BRITISH FOSSILS.

“ The stratigraphical distribution of the four British Oolitic Pygasters is as follows:—
Pygaster semisulcatus, Inferior Oolite and Great Oolite;

Pygaster conoideus, Inferior Oolite ;
Pygaster Morrisii, Cornbrash ;
Pygaster umbrella, Coralline Oolite.

“Tt was an error in the determination of the species, which led Professor Phillips to
state that Pygaster semisulcatus was found in the Coralline Oolite of Yorkshire, that

form never yet having been found in Yorkshire out of the Whitwell beds,—Inf, or Great —
Oolite.”

March 1856.

DECADE 5_PL.9._

Geolagical Suevep of the United Kmgdom HEMIASTER

(Cretaceous) — -

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HEMIASTER muRcHIsoNIA — Dantell.

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So POS sli

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BRIT

DECADE V.* PLATE IX.

—-=

HEMIASTER MURCHISONIZ.

[Genus HEMIASTER. Desor, 1840. (Sub-kingdom Radiata. Class Echinoder-
mata. Order Echinide.. Family Spatangacez.) Body obtusely cordate, tumid ; dorsai
ambulacra dissimilar, petaloid, lodged in depressions, and surrounded by a simple peri-
petal fasciole ; tubercles of the dorsal surface small and similar ; anus terminal, supra-
marginal ; no sub-anal fasciole ; mouth eccentric, bilabiate. |

Diaenosis. EZ. corpore tumido, ambitu subcordato; ambulacris dorsal-
bus profundis, postero-lateralibus brevissimis ; fasciola lata, evanescente.

2

Synonyms. Spatangus, Switu, Strat. Syst., p. 37. fig. 3., ‘Brickearth
plate. Memiaster inequalis, Forses, MS. in Morris’s Cat. 2nd edit. p. 81.
(not Brissus inequalis, Forbes, Pondicherry Fossils, 1846, Trans. Geol.
Soc. t. 7. p. 160. pl. 19. £.6.) Hemiaster inequalis, Ac. and Desor, Cat.
1847, p. 2. D’Orb.-Prod. iy. p. 829.) Micraster Murchisoni, Morris, Cat.,
Istedit. 1843, p.55. Brown, Index, p.724. Spatangus Murchisonianus, Manx-
TELL, 1835, Geol. Tr. 2nd ser. v. 3. p. 210, in part. Desmovzins, Ech.,
p.412.(notLchinospatangus Liurchisonie, KOnte, Icones, 169. unpublished).

A memorandum in the handwriting of Professor Forbes suggests
that this species might possibly be included in the group of
Cretaceous urchins figured (but not yet described) by M. d’Orbigny,
under the name Epiaster, and distinguished by the absence of any
fasciole. The species of Epiaster, however, are rather to be regarded
as Micrasters wanting the sub-anal fasciole, and in this group should
be included the Micraster cor-anguinum, var. gibbus, of Decade
EET pl 10, £21, 12.

The specific name is applied in the belief that this is identical
with the Spatangus Murchisonie of collectors, found in the upper
Green Sand of Nurstead and Devizes, although not the species
figured by Konig, which is nothing more than a crushed specimen
of Holaster levis.

Description.—tThe typical specimen (a) is extremely tumid, much
more so than is represented (f. 3 and 4) in the plate. The measure-
ments and number of ambulacral pores are accurately stated in the
following memorandum by Professor Forbes :—

[Vv. 1x.] 51

2 BRITISH FOSSILS

“Tn the British Museum are three specimens of this species from
Blackdown. They differ from each other considerably in form, and
in degree of depth of the dorsal ambulacra.”

ee B. C.
Length - - ee ~ ees 1+
Breadth - - T= - 1 1
Height - . _— - EE es 0,8;
Anterior ambulacra (pores) 28 pairs 26 - 24
Antero-lateral - 43 - 36 - 30
Postero-lateral ~ 20 - 22 - 16

The specimen B. is apparently adult, but dwarfish ; and C. is a
very young individual with the ambulacra but slightly impressed.

In the larger specimen the vertex is considerably behind the
centre; the dorsal ambulacra are deeply impressed ; the anterior
sulcus becomes shallow at the margin, and is prolonged to the
bilabiate mouth ; the posterior end is slightly flattened, and nearly
vertical ; whilst in the smallest specimen it slopes at an angle of
73°. The vent is high up, small, and elliptical ; the plates on each
side of it have slight central prominences, converging to the caudal
protuberance, beyond which on each side is a moderately projecting
lateral boss.

The anterior ambulacral hollow is wide, finely granulated and
tuberculate ; the pairs of pores are separated by distinct tubercles.
The lateral grooves are nearly smootn ; the antero-lateral pair are
shorter than the odd ambulacrum, and doubly curved ; the posterior
pair are less than half the length of the front pair, The spaces
between the petals are pinched up near the apical disk, and more
densely and roughly tuberculated.

The apical disk is composed of four perforated genital plates, of
which the right* antero-lateral includes the madreporiform body ;
there are five perforated ocular plates.

The surface of the test is very finely granulated above, with few
scattered tubercles in the peripetal zone ; the tubercles are more
numerous and regularly distributed on the sides, econ larger
towards the base.

Afinities—In its contour, and the form and proportions of its
dorsal ambulacra, the Hemiaster Murchisonie agrees with the

* Incorrectly stated to be the Jeft in the description of Micraster cor-anguinum,
Decade II.

‘

BRITISH FOSSILS. 3

typical species of the genus, and especially with the H. Bailyi
of the Gault of Folkstone, from which it is only distinguishable
by the absence of any proper fasciole. In H. Bazlyi, the peripetal
fasciole is narrow and distinct, being more finely granulated
than the adjacent surfaces, although a very few tubercles are found
encroaching upon it. In H. Murchisoniw there is a very wide
space surrounding the ambulacral petals, over which tubercles are
more thinly scattered ; the miliary granules in this band appear
scarcely finer than over the rest of the surface, but this may be
partly due to the condition of the specimens, which though silicified
are slightly weathered. Ten specimens have been examined.

Locality and Formation.—At present this species is only known
to occur in the GREEN SAND of Blackdown, Devon, where it is the
only urchin of frequent occurrence.

DESCRIPTION OF THE PLATE.

. Upper view (of specimen in the British Museum).

. Under side of same specimen.

3. Terminal view (of a more depressed example).

Fig. 4. Lateral view; the outline indicates the profile of specimen represented by
figs. 1,2. This figure (4) is represented as much too depressed, probably
from being crushed, the dotted lines represent it more truly.

5, Apical disk magnified.

6. Details of the ambulacra.

Fig. 7. Anterior ambulacrum magnified.

8. Portion of the surface adjoining the right postero-lateral ambulacrum, magnified
to show the diffused condition of the fasciole.

Fig. 9, 10. Tubercles of the lateral surfaces magnified.

ke
—

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Note on other British species of Hemiaster.

In addition to the Hemiaster inequalis, Mr. Morris enumerates the following as species
to be described by Prof. Forbes in the Fifth Decade :
Hemiaster asterias, Gault, Folkstone.
Hf, Bailyi, Gault, Folkstone.
HT, Morristi, Chalk Marl, Dover.

1. Hemiaster asterias, Forbes, Morris’s Catal., 2nd edit. 81.

The specimens with this name attached are not in a sufficiently well-preserved state
to admit of exact comparison and description (the best example being at Edinburgh,
and, at present inaccessible). The vertex appears to have been more prominent
and further back than in the species figured, or in H. Bailyi, and the dorsal ambu-
lacra may be longer and narrower in proportion.

Locality —GavtutT, Folkstone. (Mus. Pract. Geology.)

4 BRITISH FOSSILS.

2. H. Bailyi, Forbes, MS. Morris’s Cat., 2nd edit. p. 81. Holaster argillaceus (part),
Morris’s Cat., Ist edit. p. 54. Echino-spatangus, Mantell, Geol. Sussex, p. 86.

The specimens of this Hemeaster are all more or less crushed, -but the most perfect
agree in their proportions with the figured specimens of H. Murchisonie. One
example, of the size of the figure, has the same number of ambulacral pores as
specimen B., viz. 26, 36, 22. The peripetal fasciole is quite distinct, narrow, and
simple in its contour, passing from end to end of the ambulacral petals, and only
slightly contracted at the sides. The surface of the Gault urchins is usually rough,
with nodular concretions of iron pyrites formed upon the tubercles. So many of
the Blackdown fossils are identical with species of the Folkstone Gault, that we
have felt considerable hesitation in admitting as specific, a character which may
by any possibility be due to the mineral condition of the specimens,

Locality.—Gavxt, Folkstone.

3. H. Morristi, Forbes, MS. Morris’s Cat., 2nd edit. p. 81. Echinospatangus cordi-
formis (part), Mantelil, Geol. Sussex, p. 108. Hemuaster punctatus, D’Orb. Ter. Cret.,
pl. 886. ? (no description). Spatangus complanatus, Mantell, Medals, Ist edit. p. 355. (not
figured).

This not uncommon species has been long known to English collectors by a variety
of incorrect names, but it is entirely distinct from any species with which we have
been able to compare it, except the Hemiaster punctatus of D’Orbigny, the descrip-
tion of which has not yet appeared. ‘The largest specimen of Dr. Mantell’s
measures in length 24, breadth 2, height, 13 inches. One of ordinary dimensions
measures lon. 17, lat. 16, alt. 10 lines. The outline is oval and slightly polygonal ;
the anterior sulcus broad and obscure; the posterior end flai, and sloping at an
angle of 70° (not vertical as in H. punctatus). ‘The under side is but slightly
flattened, the margins tumid, the vertex depressed and central. ‘The ambulacral
petals are small, moderately impressed, and surrounded by a distinct fasciole, which
passes from point to point with scarcely any curvature. The surface, when well
preserved, is rough with unequal tubercles, which are perforated, seated on
crenulated bosses, and surrounded by a sharply-defined plain ring; they are so
crowded as seldom to allow the formation of a complete circle of miliary granules.

Localities —LowER CuaLtK, Dover (Mus. Pract, Geol.) and Hamsey, Sussex (Brit.
Mus. Mantellian Collection).

4. H. bucardium, Goldf. sp. (sec. Bronn, Index, p. 723.) Mucraster lacunosus,
Morris’s Cat., 1st edit. p. 55. (not Parkinson).

This fine species is omitted in the second edition of the Catalogue of British Fossils ; it
agrees very well with the figures of Goldfuss. In the British Museum there is a
single specimen of another species, equalling H. bucardium in size, and apparently
undescribed.

Locality.—Urrer Green Sanp, Warminster.

S. P. WooDWARD.
March 1856.

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BRITISH FOSS LL

DECADE V. . PLATE X.

BRISSUS SCILLE.

[Genus BRISSUS. Krein. (Sub-kingdom Radiata. Class Echinodermata. Order
Echinoidea. Family Spatangide.) Body oval or oblong, tumid; dorsal ambulacra
subpetaloid, circumscribed by a peripetal fasciole ; tubercles of dorsal surface all similar ;
anus terminal, supra-marginal; caudal extremity with a sub-anal fasciole. |

Dicnosis. B. dense tuberculatus (tuberculis anticis majoribus) oblongo-
ovatus elevatus nec inflatus, margini subcompresso; vertice excentrico ;
interambulacro postico plus minusve carinato; ano verticali; fasciola
peripetali anterius sinuata et utraque semel nec bis angulariter inflexd.

Rererence. Scilla; de Corp. Marinis, pl. 14. f 2,3. (Spatangus
Bei, Philippi in Erichs. Archiv. for 1846, pl. 1. p. 349 ?) Briss.

Scille, Acassiz and Drsor (1846), Ann. Sc. Nat., ard ser. tom. 8. p. 18.
Forses (1852), Paleontograph. Soe. Trans. (Ech. of the British Ter-
tiaries) p. 15. pl. 2. fig. 4. in Morris’s Catal., 2nd edit. (1854), p. 78.

“This sea urchin, one of the largest and most remarkable of all
those found fossil in the crag, varies much in propor tion, but 1s
distinctly identical with Scilla’s species, Which lives m the Medi-
terranean, and occurs fossil in the Miocene of Malta. I purposely
omit, however, all references to Lamarck, as there is sad confusion
about this Brissus and its allies.

“ Description.—The length of our fine specimen, presented to the
Museum of Practical Geology by E. H. Bunbury, Esq., is 48, inches,
breadth 3 inches, height 24 inches. The species varies much in
shape, some specimens being oblong, some wide and ovate; the
former are usually high, and stron ae subcarinated on the mee
the latter are more deve essed ; but all have the apex strikingly
eccentric, and the anterzor* extremity abruptly truncated.

* Probably “ posterior” was intended to be written here, but the word is preserved,
as it is possible Prof. Forbes intended the steep slope of the anterior end. It can scarcely
be called “ truncated,” much less “ abruptly truncated,’”—J. W. S.

hee al 5K

2 BRITISH FOSSILS.

“The greatest width of the body is nearly on a line with the
termination of the postero-lateral ambulacra. The tubercles of the
back are numerous and closely set, and increase gradually in size
in the anteal region, and towards the apex. The lateral ambulacra
are narrow, somewhat linear in shape, and deeply impressed,
showing on the surface as four radiating furrows, two of which, the
antero-lateral ones, stand at right angles to the longitudinal
diameter of the test, whilst the other two, the postero-laterals, are
directed obliquely backwards, and form with one another an acute
angle at their apical terminations. The posterior pair of ambulrera
are a little longer than the others, and contain rather more pairs of
pores, the respective numbers in each row being about 27°30 or 30°35.

“The centro-ambulacral space is smooth, or nearly so, in the lateral
ambulacra, but in the odd or anteal ambulacrum, which, instead of
being impressed and subpetaloid, is linear and plain, or even slightly
elevated.* It is regularly and minutely granulated, the large granules
or small tubercles forming boundary rows. In the lateral ambulacra
the ridges separating the pairs of pores are minutely granulated.

“The genital disk, usually obscured in fossil specimens, has four
genital holes, the two posterior ones largest, and five eye perfora-
tions of a peculiar structure.

“The peripetal fasciole is very pro marked. In front of the
antero-lateral ambulacra it includes a wide somewhat semicircular
space, its foremost and central portion crossing the shell at a little
below half its height. From this point tracing its course along
each side, it runs with a slight angularity to about two thirds of the
distance between the anteal ambulacrum and the end of the antero-
lateral one, before meeting which it makes a single strongly marked
incurved flexure, in this respect differing from Brissus carivnatus,
the fasciole of which has two inflexions in this region. It then
winds closely round the end of the antero-lateral ambulacrum, and
ascends rapidly between it and the postero-lateral one, making a
deep but wide flexure, somewhat truncated at its upper part, then
curves down, following closely the bounds of the postero-lateral
ambulacra, round which it winds and crosses the posterior inter-

* In this fossil specimen, much more so than in any of the recent ones in the British
Museum. ‘The carination of the back, too, is considerably more marked.

Is there really any difference between the B. carinatus, Lam, from the Mauritius, and
this Mediterranean species? ‘The double angle of the fasciole is not always constant in
B. carinatus, or absent in B, Scilla. ‘The overhanging of the posterior end in the former
is a better mark of difference, but a specimen in the British Museum from the Mauritius
has it nearly perpendicular. ‘The granulation, under surface, and ambulacra are very
much the same in both.—J. W. S.

BRITISH FOSSILS. 3

ambulacral space, with an arched curve not so deeply inturned as
the lateral curves are.

“The anal extremity of the test is perpendicularly truncated
(a character also distinctive between this species and B. carinatus),
the anus lenticular and large, and placed rather low down, and the
sub-anal or caudal fasciole broadly obcordate, truncated below. The
mouth is transversely semicircular, with a slightly overhanging and
prominent lip. The oral ambulacra are subtriangular. The tubercles
of the post-oral spinous region are subequal and radiating, and closer
set than on the lateral spaces, or in front of the mouth.”

Locality.—CORALLINE CraG, Iken, Ramsholt, and Sudbourn, in
Suffolk. (Mus. Pract. Geology, British Museum, &c.)

Foreign Localities—M10cENE, Malta (Prof. Forbes). (Mus.
Pract. Geology.)

IEXPLANATION OF THE PLATE.

Fig. 1. Brissus Scilla, Ag., from Iken (Mus. Pract. Geology).

Fig, 2. Side view of do.

Fig. 3. End view, showing the anal opening and sub-caudal fasciole.

Fig. 4. Lateral view of another specimen, the vertex placed more anteriorly.

Fig. 5. Under view of recent specimen, to show the plates of the mouth.

Fig. 6. Genital openings and ocular plates, with the madreporic plate occupying the

place of the fifth genital pore.
Fig. 7. Portion of peripetal fasciole, magnified.
Hig. 8. ‘Tubercles and granules, magnified.
Fig. 9. Ambulacral pores, magnified.
Fig. 10-13. Spines more or less maguified.
Fig. 10. Is a lateral view, and 11, a front view of a spine with a spatulate tip.

March 1856. K. ForBES (1852),

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APPENDIX TO DECADE V.

By S. P. Woopwarp, Esq., British MUSEUM.

The Appendix contains descriptions of species referred to in the 2nd edit. Morris’s
Catalogue, for description in this Decade. ‘To these one or two new species of the
same genera are added, as also some additional species intended to be supplementary
to descriptions in former Decades.

Genus Crpuosoma, Ag.—Phymosoma (D’Arch.), Desor.

1. C. Koénigi, Mantell (1822), Geol. Sussex, p. 189. Cidarites variolaris,
Goldf., t. 40, f.9 (not Brongn.) Cyphosoma ornatissimum (Ag.), Morris’s
Cat., 2nd ed., p. 75. CC. variolare, Forbes, in .Dixon, Fossils, p. x.
pl. 25, f. 29. C. Millert (Desm.), Forbes, in Dixon, p. 340, pl. 25, f. 26,
27. Phymosoma Koenigii, Desor, Synopsis, p. 86.

This species varies in diameter from Jess than an inch to two inches ;
small examples are rare. ‘The spines are short, straight, and round, con-
tracting suddenly, and sometimes bent and angular near the point. Long
spatulate spines also occur, associated with the normal test.

Mr. Bowerbank’s cabinet contains a remarkable monstrosity of this
species, which is inversely conical, like Diadema tumidum. It is
9 lines high, and 16 lines in diameter above, contracting below
down to the oral opening, which appears at first to be the summit.

Locality.—Urrer Cuatx, Kent, Sussex, Norfolk, Wiltshire, York-
shire.

2. C. granulosum (Cidarites), Goldf., Petr. t. 40, fi 7. Desor, Syn.
p- 87. Probably only a variety of the preceding species.

The primary tubercles are larger and more prominent ; the accessory
tubercles are quite wanting in young specimens, and but slightly developed
in the largest examples, which nearly equal the C. Kenigi in size. The
base is flat, or slightly convex from the peristome outwards.

Locality —Most abundant in the Lower Cuatx of Kent and Sussex.

3. C. spatuliferum, Forbes (1850), in Dixon’s Geology of Sussex, p. 340,
pl. 24, f. 21. (Coll. Mrs. Smith, of Tunbridge Wells.) Cyphosoma sp.
(junior), Dixon, Sussex, tab. 24, f. 28-31.

Body small, circular, and rough with numerous small prominent
tubercles ; lat. 10, alt. 4 lines; areole plain above, radiated below ; base
concave, mouth small, lat. 4 lines, apical opening pentagonal, irregular ;
pores in single file ; ambulacral segments prominent, tubercles 8-10, largest
at the circumference, with nearly confluent areole; interambulacral

[v.]

yA BRITISH FOSSILS.

tubercles 9 in each row, bordered with very minute lateral tubercles, and
divided by a conspicuous miliary furrow ; spines very much flattened.

Locality.—Rare in the Upper Cuaxx of Kent and Sussex.

4. C. tiara, Ag., An. Sc. Nat., 1846, p. 351. Morris’s Cat., 2nd ed.,
p.75. Cidaris tiara, Hagenow. Phymosoma sazxatile, Desor, Syn. p. 87.
“‘ Nearly equally depressed above and below. A range of very incon-
spicuous secondary tubercles on the base, upon each side of the interambu-
lacral areas, but disappearing at the circumference. Miliary tubercles very
few. Pores reduplicate.”— Desor. |

This species was introduced into the English catalogues on the
authority of M. Agassiz himself, but the specimen so named by
Prof. Forbes appears to be only a casual variety of C. K6nigi.
M. Desor’s description answers best to C. corollare. He revives
the name given to an urchin imbedded in flint, by Parkinson, who
identified it with the living Echinus saxatilis. He also quotes
Mantell’s figure, which would be equally indeterminable, but that
the specimen is preserved in the British Museum, and proves to be

C. spatuliferum. |

Locality.— Urrer Cuan, Gravesend, Kent.

5. C. corollare (Park.), Forbes, in Morris’s Cat., 2nd ed., p. 75.

Body circular, depressed, lat. 12, alt. 4 lines (usually smaller), base
concave, oral opening small (lat. 4 lines), apical opening large, pentangular
(lat. 5-55 lines) ; pores crowded near the summit; primary tubercles
small, with plain areole ; interambulacral tubercles 9in a row, with small
irregular marginal and wide granular interspaces, becoming smooth
above ; ambulacral tubercles 9-11, tapering to either end. Spines long,
slender, and spatulate, one-fourth longer than the diameter of the test.

Locality.—Very common in the Upper Cuatx of Kent, and not un-
frequently with the spines 77 situ.

6. C. Wetherelli, Forbes, in Morris’s Cat., 2nd ed., p. 7.

Like C. spatuliferum ; but the interambulacral tubercles bordered by pro-
minent miliary granules, and by small lateral tubercles on the under
surface only.

The unique typical example, partly imbedded in flint, was obtained
at Gravesend, and presented to the Museum of Practical Geology
by N. T. Wetherell, Esq., F.R.S. In the absence of further evi-
dence, it can only be considered a variety of the last species.

Locality._-UrrER CHALK, Gravesend.

7. C. simplex, Forbes, in Morris’s Cat., 2nd ed. p. 77.

Body small, convex, lat. 9, alt. 45 lines ; base concave, mouth small ;
apical opening pentangular ; primary tubercles prominent at the circum-
ference, small and inconspicuous above ; areole radiated, large and nearly
confluent at the middle, very small above, and separated by a wide finely

APPENDIX TO DECADE V. 3

granulated miliary furrow; interambulacral tubercles 9, 10, with small
laterals on the under surface ; ambulacral tubercles 8, 8, with large con-
fluent areole at the circumference. Pores in single file.
The test of this species is more highly ornamented than any of the
_ preceding forms, but the upper surface appears nearly plain unless
examined with a glass.

Locality.—Common in the hard gritty CHatk of Dover, and occa-
sionally found in the CHALk with flints in Sussex.

8. C. difficile, Ag., Cat. Syst., p. 11. Diadema rotatum, and D. M‘Coyi,
Forbes, in Morris’s Cat., 2nd ed., p. 76,77. Diadema rotulare, M< hoe (not
Ag.). Glyphocyphus difficilis, Desor, Syn., p. 104.

Body small, lat. 7, alt. 3 lines, convex above, slightly concave beneath ;
mouth circular, lat.24 lines ; apical disk equal to the oral opening, flat, finely
granulated ; ocular plates rather large, perforated close to the ambulacral
margin ; genital plates perforated (with a sur-anal plate in the centre ?),
and the madreporiform body on the right anterior plate; poriferous
avenues nearly straight, distinct, with the pairs of pores in single series ;
tubercles prominent, quite smooth unless weathered, placed on crenulated
bosses ; ambulacra narrow, straight, with remote alternate tubercles ir-
regularly developed, 3, 8, or 7, 8; interambulacrals in two straight rows
of 8, 9, surrounded by small strongly radiated Meo and divided by deep
sutural notches.

Small specimens, measuring 4 or 5 lines, are abundant, and usually
overlooked as the young of the Diademas, but may be readily dis-
tinguished by the sutural notches. ‘The more convex examples
agree with the published mould of M. Agassiz’s type specimen of
C. difficile, but there is nothing in the description of C. suleatum,
Ag., to distinguish it from the same urchin. An unusually large
specimen (in the cabinet of Mr. Sloper, of Devizes) measures 9 lines
across and 44 in height ; both rows of ambulacral tubercles are
well developed, and the miliary granules form a prominent frame-
work to the tubercles. ‘wo specimens have occurred with the
apical disk, one of which is in the Brit. Mus., and the other in
Mr. Cunnington’s Collection.

M. Desor refers this urchin to D’Archiac’s Glyphocyphus (which was
founded on the Temnopleurus pulchellus of Sorignet, Echinopsis
pusilla, Roemer, and incorrectly described as having the tubercles
imperforate, and bosses not crenulate), but the structure of the
apical disk is altogether different.

Locality.—CHALK Mart, Dover (Mus, Brit. and Tennant). Uprrr
GREEN SAND, Warminster.

9. C. mespilia, n. sp.
Body small, circular, inflated or depressed, convex above and below,
with sub-equal apertures ; lat. 5, alt. 3 lines; poriferous avenues quite

4, BRITISH FOSSILS.

straight and simple, pairs of pores very oblique ; tubercles minute, pro-
minent, imperforated, and crenulated ; areole small, radiated, with
elongated miliary granules, sutures grooved ; interambulacra with two
rows of 7, 8 tubercles; ambulacra very narrow, with 7 or 8 tubercles,
alternate and irregular.

Locality.— LOWER CHALK, Dover (Mus. Brit. and Bowerbank). This
small but very distinct species has only been found in the hard
Wuite Cmax, along with C. simplex and Salenia granulosa.

10. C. Aftddletoni, n. sp.

Body circular, tumid, concave beneath; lat. 10, alt. 6 lines ; mouth
small, depressed, lat. 34 lines; apical opening pentagonal, elongated,
lat. 4-5 lines ; pores in single file; primary tubercles small, in sub-equal
rows of 12 each, the 6 uppermost minute ; areole large at the circum-
ference, nearly confluent ; interambulacral tubercles bordered above by
6 nearly equal accessories, and divided by a broad furrow, smooth in the
centre : secondary tubercles also developed on the base.

Locality—Urrrr Cuatx, Norwich. This unique specimen was

placed in the hands of Prof. Forbes, for description, by John Mid-
dleton, Esq., of Norwich.

SALENIA, Gray.

In the 2nd edition of Prof. Morris’s Catalogue of British Fossils, p. 89,
the following species of Salenia are referred to, as described by Prof.
Forbes in Decade V. No MS. having been left, the following notes are
drawn up from the type specimens in the Museum of Practical Geology.

1. Salenia Austenit, Lower Chalk, Dover.
S. Bunburyi, Lower Chalk, Mildenhall.
. S. Clarkii, Lower Chalk, Dover.
. S. clathrata (Ag. MS.), Upper Green Sand, Warminsier.
S. granulosa, Lower Chalk, Dover.
. 8. Portlocku, Upper Chalk, Ireland.
. S. umbrella (Ag. MS.), Upper Green Sand, Warminster.
S. ornata (Ag. MS.), Upper Green Sand, Warminster (Decade I.
Oy Pe 2). )

1. S. Austeni, Forbes, MS. Like S. petalifera, Desm.

Body tumid, depressed, lat. 10, alt. 6 lines; apical disk comparatively
small, 5 lines in diameter ; the plates ornamented with serrated ridges
running in pairs from their centres, and meeting to form a sort of trellis.

bo

CO ~ID Cr yh Oo

Two of the original specimens, in the Museum of Practical Geology,
are more distinct from S. petalifera than any other examples. The
apical disk of S. petalifera is very finely granulated, but, as
remarked by Prof. Forbes (Decade I. 5, p. 3), “a few rare
specimens exhibit indistinct indications of radiated ribbing.” In
the Grey Chalk of Dover, some examples are nearly plain, others

j
4
i
.

APPENDIX TO DECADE V. 5

highly ornamented, but never two alike. The sutural pores
appear more numerous in the sculptured specimens, there being
5 to each ocular plate.

Locality. —LoweEr (or Grey) Cuark of Dover.

2. S. Clarkii, Forbes, MS.

Body 6 lines in diameter, 4 in height; apical disk rather small,
scarcely exceeding 3 lines in diameter, the plates rough, with raised points ;
each genital plate. with five furrows leading to the sutural pores, which
are like those of S. petalifera, but larger ; ambulacra rather narrower
than in S. petalifera; spines slender, cylindrical, finely striated and
granulated, the longest exceeding 1 inches in length, and less than 1 line
in diameter, frequently forked at their extremities, and sometimes bent
and distorted.

This species is scarcely to be distinguished from those Warminster
specimens which have been referred to S. gibba, Ag.; but is
entirely distinct from the mould of M. Agassiz’s original example.

Locality — Grey Cuatx, Dover. (Mus. Pract. Geol. and Brit. Mus.)

3. S. granulosa, Forbes, MS. Morris’s Cat., 2nd ed. p. 89. S. seuti-
gera? Forbes, in Dixon’s Geol. Sussex, t. 25, f. 24.

Body small, lat. 6, alt. 34 mill..—sometimes it measures only 14 lines in’
diameter ; oral opening large, not depressed ; apical disk very large,
lat. 44 lines, plates finely sculptured with rugose lines, sometimes radiated,
sutures quite simple ; primary tubercles few and prominent ; miliary zone
irregular, granulose ; ambulacra narrow.

Locality.— Lower CuHax, Dover. Found along with Cyphosoma
simplex and numerous Bryozoa, in the hard gritty beds of White
Chalk. (Mus. Pract. Geol., Brit. Mus.)

4. §. Porilocki, Forbes, MS. Morris’s Cat., 2nd ed., p. 89. Cidaris
vesiculosus, Portl., Geol. Rep., t. 18, f.5. S. seutigera? Forbes, Dixon’s
Sussex, pl. 25, f. 23. S. geometrica, Ag., Mon. d’Ech. Salenies, p. 11,
t. 1, f. 25-32. |

Body subglobose, elevated, convex above, contracted and concave
beneath, lat. 9, alt. 8 lines; mouth small, lat. 3 lines; apical disk
moderate, lat. 6 lines; plates slightly radiate; sutural perforations rather
indented ; ambulacra narrow, sinuous, tubercles separated by two rows of
granules ; interambulacral tubercles 7-8, those near the mouth (3, 4) very
small ; miliary zone wide. |

The specimen described belongs to Mr. Searles Wood ; another, in
the cabinet of Mr. John King, of Norwich, measures 11 lines in
height, and the same in diameter ; and there is a fine specimen in
the Hunterian Collection. The agreement of this species with
S. geometrica has been overlooked on account of an error in

6 BRITISH FOSSILS.

the figure given by M. Agassiz; the published mould is quite
like our fossil :—“ L’espace entre les deux séries de gros tubercles
est parsemé, comme dans lespéce précédente (S. petalifera), mais
en nombre moins considerable, de trés-petites granulations, qui ont
été omises par erreur dans le dessin.”

The Cidaris acrocidaris, Portl., from the Irish Chalk, is a flint cast of
a small Salenia resembling that figured in Dixon’s Geology of
Sussex, pl. 25, f. 25. It may be the cast of one of the un-named
species (of which there are several in the British Museum) found
in Scania and at Ciply.

Locality.—This beautiful species occurs in the Cuaxx of the North
of Ireland, and, very rarely, in the Upper Beps or CHALK at
Norwich, and in Sussex. It is also found at Havre. Flint casts
are not uncommon in the gravel of Norfolk.

5. S. clathrata, Ag., MS. Mborris’s Cat., 2nd ed., p. 89.

Body subglobose, very convex above ; lat. 6, alt. 44 lines ; apical disk
lat. 54 lines, nearly covering the upper surface, its outline very deeply
indented between the ocular and genital plates ; anal opening with a very
prominent margin ; plates smooth, deeply notched at the sutures, those
connecting the centres of the plates forming a distinct pentagon, and each
of the genital pores is the centre of five radiating grooves, with angular
pits between ; ambulacra narrow ; tubercles few and prominent, separated
by a narrow miliary zone.

The smallest specimens found at Warminster are very gibbous, and
appear to be dwarfs, rather than young individuals. The species
attains a large size in the Grey Chalk, and are occasionally more
depressed, with the marginal lobes of the anal disk broader, and
the sutural grooves less excavated. The name S. umbrella (Ag.,
MS.) appears to have been intended for those specimens with the
sutural grooves most deeply and sharply defined. The figure in
Parkinson’s Organic Remains (vol. iii. pl. 1, f. 13), referred to by
Prof. Forbes, in Decade I. as “S. ornata, Ag. MS.,” is indeter-
minable.

Locality.—Urrer GREEN SAanp, Warminster; Grey Cuan, Dover.

6. S. Bunbury, Forbes, MS. Mporris’s Cat., 2nd ed., p. 89.

Body subglobose, tumid above, with a wide base, and depressed oral
aperture ; lat. 7, alt. 54 lines; apical disk, 54 lines in diameter, vent
with a prominent thickened border, plates sculptured at the border of
the disk, sutural notches forming deep linear grooves (as in S. umbrella) ;
ambulacra narrow, sinuous, with small remote tubercles divided by a
prominent granulated ridge ; interambulacral tubercles 4, 5, prominent,
divided by a wide miliary tract.

Locality —LowrEr CHa.x, Mildenhall, near Bury St. Edmunds. The
original and unique specimen in the Mus. Pract. Geol. was pre-
sented by E, H. Bunbury, Esq., M.P.

a

=

APPENDIX TO DECADE V. 7

7. S. punctata, Desor.

This is the only British species belonging to the section Peltastes, Ag.,
in which the sur-anal plate is placed between the vent and the odd
ambulacrum ; a specimen in the late Dr. Mantell’s Collection has
the vent situated as in the normal Salenias.

Locality. GREEN SanD, Farringdon. The specimen from the Kentish
Rag of Hythe, presented to the Mus. Pract. Geol. by H. B. Mackeson,
Esq., differs in no respect from Farringdon specimens of the same
size.

Cardiaster grandis, Benett. sp., Spatangus grandis, Benett (1831), Cat.
Org. Rem. Co. Wilts, p. 7. (S. Woodward, 1835. Monograph of Brit.
Fossil Echinide. MSS. in Mus. Pract. Geol.)

Oblong, cordiform, inflated ; vertex moderately elevated, anterior sulcus
rather deep ; lateral ambulacra not impressed, pores symmetrical; primary
tubercles regularly distributed and equal in size above the lateral fasciole,
rather more crowded below, and larger on the under surface ; the upper is
densely covered with miliary granules, leaving annular spaces round the
tubercles; post-oral spaces elongated, covered with rather larger tubercles,
surrounded and divided by single rings of granules. Lon. 34; lat. 23 ;
alt. 2 unc.

Locality—Urrer Cuarx, Norwich (Coll. J. King). “Chalk and

Flint, Heytesbury, Wilts.” (Mus. Benett; Brit. Mus.)
Cardiaster Cotteauanus, D’Orb., Ter. Cret., pl. 830.

Locality.—Mr. Baily has recognized the occurrence of this species in
the Upper Cuak of Kent. There are two specimens from Dover
in the Museum of Pract. Geol., and one considerably smaller, and
somewhat different, from the Upper GREEN SAnpD of Warminster,
in the British Museum.

Epiaster crassissimus, D’Orb., Ter. Cret., pl. 860.

A specimen in the Mus. Pract. Geol., from the hard Grey CHALK of
Dover, only differs from D’Orbigny’s figure in being more de-
pressed. Auother species, from the Upper Cua of Dover, in
the Brit. Museum, has extremely small and scarcely impressed
ambulacral petals; the surface is perfectly preserved, but exhibits
no fascioles.

Micraster Mantelli, Forbes, MS. Morris’s Cat., 2nd ed., p. 83.

The specimens with this name attached do not differ in any respect
from those recognized as the young of MW. cor-anguinum ; at this
age they are always very tumid, and the dorsal ambulacra are
scarcely at all impressed.

Locality.—UPrer CuHark of Dover and Kent.

S. P. Woor warp.

pee ies

| Decape VI. Prats VI.

For HISTIONOTUS BREVICEPS read OPITIOPSIS BREVICEPS. |

HS part | “Fi a Wiiwar, &

MEMOIRS

OF THE

GEOLOGICAL SURVEY

OF

THE UNITED KINGDOM.

OLS POLOLLS BODIO DIDO LODE IA PE PELOEL ELIE LG LIE IIGO SD

Fiquers ond Descriptions

BRITISH. ORGANIC REMAINS.

oe

DECADE VI.

POPPA ODP LS EL EPIL GP PLE GLPLE PEP EL EL PLE LPP GPPP PECL

PUBLISHED BY ORDER OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY.

LONDON:
PRINTED FOR HER MAJESTY’S STATIONERY OFFICE:
PUBLISHED BY

LONGMAN, BROWN, GREEN, AND LONGMANS.
, 1852.

Lb erie repr SA only io Apri a act eh Roem To

fakes sua
ap Ne |

RS Ten ft

inssterea

Pw Pree Pos Gris.

DECADE THE SIXTH.

THis the Sixth Decade of representations of British Fossils is
devoted to the illustration of some new genera and species of
extinct fishes.

The comparative rarity of these fossils renders it impossible to
conform to the plan adopted in the preceding Decades of grouping
the subjects either according to natural relations or stratigraphical
position. The same cause precludes also the possibility of selecting
from the collections of the Geological Survey a sufficient number of
novelties to complete a Decade.

In accordance, nevertheless, with the request of the Director
General, that I would undertake the production of an Ichthyological
Decade, I have accomplished the task by selecting subjects from my
own cabinet and elsewhere, either entirely new, or little known,
none of which have hitherto been figured.

Of these the most interesting is the unique chalk ichthyolite in
the collection of the British Museum, described in the last article.
The other descriptions comprise a new Paleoniscus, from the coal-
measures ; new species of the genera Lepidotus, Pholidophorus,
Ptycholepis, and Leptolepis, from the Oxford clay and lias forma-
tions ; an Oplhiopsis, from the Purbeck strata, near Tisbury ; and a
detailed account of a Chimeroid fish, Elasmodus Hunteri, from the
London clay.

The curious structural details of the latter specimens are beauti-
fully delineated in the first copper-plate. The same process of
[v1.] b

BRITISH FOSSILS,

illustration was attempted for the other plates, but the time and
labour requisite to produce satisfactory results proved to be so
oreat, that, after the completion of one plate, No. 3 of the Decade, it
was considered advisable to have recourse to lithography for the
the remainder.

These lithographs have been so beautifully drawn by Mr. Dinkel,
that I trust the result of the experiment may be considered suffi-
ciently satisfactory to warrant the employment of this style of
illustration in any subsequent Decades devoted to this branch of
British Paleontology.

P. bE M. Grey EGERTON.
Apri 8, 1852.

,
ane pet es ‘ ‘ ; i i
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Geological Surbev of the Mnited Kingdon.

ELASMODUS HUNTERI _Ligertow.

Jos.Dinkel delt E.Forbes dixex*

DECADE 6G. Ph.

HLASMODUS

( Tertiary )

JW. Lowry fe.

BRITISH FOSSILS.

Drcape Vi. Prary. 1,

-ELASMODUS HUNTERI.

[Genus ELASMODUS (2aacua, a plate, and d30vs, atooth). Ecertoy. (Sub-kingdom
Vertebrata. Class Pisces. Sub-class Elasmobranchii. Bonararte. Order Holocephali.
Mixier. Family Edaphodontide. OwEn.) Lower maxillaries having one tritor on each
structure composite, partly of bone, partly of laminated dentine; upper maxillaries bony,
intersected by a scroll of laminated dentine forming the outer margins, and a double
tritoral tooth on each; premaxillaries composed wholly of laminated dentine. |

Synonyms.—Chimera Hunteri, OwEN, Odontography, (1840-45), p. 66
Elasmodus Hunteri, EGERTON, Proceedings of Geol. Soc., 1843. ’

Deseription. —The dental apparatus of Elasmodus i is so ‘compli-
cated j in its structure, that it is a task of some difficulty. to. com-
municate to the reader an exact idea of its many peculiarities.
However adroitly this may be accomplished, an inspection of the
clear and faithful representations given in the plate will convey a
more accurate notion of these curious fossils than any verbal descrip-
tion. The arrangement of the several tissues constituting the lower
jaw is as Plone :—The anterior portion, comprising nearly one
third (figs. 1, 2, a.),- is composed of a series of laminz of coarse
dentine, superimposed on one another in the following manner. At
the symphisis the plates incline downwards and outwards, while on
the external front they maintain an horizontal direction for one
half their extent, and then slope downwards and backwards to their
termination. These are succeeded by a vertical band of coarse
fibrous bone (figs. 1, 2, b.) occupying the middle third of the jaw.
The posterior third (figs. 1, 2, ¢.) has its outer wall composed of a
series of vertical columns of laminated dentine, the points of which
give : ‘to this part of the cutting edge a notched and irregular outline
asin the recent Chimera monstrosa. Between this columnar portion
and. the bony band a thin line of dentine (figs. 1, 2, d.) occurs, formed
by the continuation of the inner edge of the large triturating tubercle,
which traverses the entire substance of the boa. The tubercle itself
is composed of dentine, and occupies a considerable part of the

[ VI. i.] 6B

2 BRITISH FOSSILS.

internal surface of the jaw, and extends from the crown to the base
(fig. 2,e.) In structure it closely resembles the analogous tritores in
the genus Hdaphodon. Both the outer and inner surfaces of the
jaw, with the exception of this dentinal plate, were invested with a
layer of harder material, as in the genus Ischyodus. The remarkable
laminated structure, which suggested the generic name, obtains in
the upper as well as in the lower jaw. As in the other Chimeroids,
Elasmodus was furnished with two upper maxillary bones, and two
premaxillaries. The former were provided with three triturating
tubercles (fig. 6, a, 6, ¢.) as in Hdaphodon ; but, unlike those of the
latter genus, the dentine of which they are composed is confluent,
being rolled round, like a scroll,in the substance of the bone; one
edge forming the margin of the tooth, the other buried deep in its
centre. In the young Elasmodus (figs.7, 8.) the two principal tubercles
were united at their bases. The premaxillaries (figs. 9, 10.) are thin,
incurved, scalpriform denticles, rounded at the cutting edge. They
have the lamelliform structure characteristic of this genus, but cor-
respond with the premaxillaries of the allied genera in the columnar
arrangement of the plates, although the columns are not separated
by septa of bone.

History.—It was not likely that any organic body, exhibiting
peculiarities of structure such as are here detailed, should be passed
by unheeded by John Hunter. The specimens figured of the lower
maxillaries and the premaxillaries (figs. 1, 2, 9, 10.) are in the
Hunterian collection. Shortly after Dr. Buckland’s ingenious dis-
covery of the affinities of the fossil Chimwroids of the oolitic and
cretaceous formations, these specimens attracted the notice of Pro-
fessor Owen, who recognised their true character, and described
them under the name of Chimera Hunteri.* In the course of my
examination of the Chimeroid family in 1843, I proposed to elimi-
nate these forms under a separate generic title, an arrangement
which the subsequent discovery of the upper maxillaries fully con-
firms. The latter were found by the late Mr. Dixon at Brackles-
ham, and fortunately show the peculiarities of the dental arrange-
ment both in the young and the adult individual.

A ffinities.—The genus Elasmodus approaches nearer to the recent
Chimera monstrosa than either Ischyodus or Edaphodon, in the
form and structure of the lower jaw, and the premaxillaries ; but
in every other respect its nearest affinity is with Edaphodon.

Localities.—This species is found in the Eocene formations of the

i Odontography, p. 66.

BRITISH FOSSILS. 2

Isle of Sheppey and Bracklesham bay. The specimens selected for
illustration are in the collections of the Royal College of Surgeons,
and the late Mr. Dixon of Worthing.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

EXPLANATION OF PLATE.

1. Outer view of the lower jaw.

2. Interior view of the same.

3. Outer view of the lower jaw (young).
4, Interior view of the same.

5s
6
Z
8

Upper view of the superior maxillary plate.

. Under view of the same.
. Upper view of the superior maxillary (young).
. Under view of the same.
2.

Outer view of the premaxillary denticle.

Fig. 10. Interior view of the same.

P. DE M. Grey EGERTON.

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DRLTISH FOSSILS,

DecaDE VI. Puarte II.

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PALEONISCUS EGERTONI.

[Genus PALAZONISCUS. Agassiz. Palgothrissum, DE BLAINvVILLE. (Sub-kingdom
Vertebrata. Class Pisces. Order Goniolepidoti. Family Lepidostei. Sub-family Lepi-
dostei heteroceri. Ist Group. Body fusiform; dorsal fin single.) Dorsal fin commences
opposite the interspace of the ventrals and anal; pectorals and ventrals small; large
fulcral scales on the anterior margins of the dorsal, anal, and caudal fins ; tail with two
lobes ; heterocerque.* |

Synonrms.—Paleéoniscus Egertoni, Acassiz, Poiss. Foss., vol. ii. p. 302.
Paleoniscus Egertoni, EGERTON, Quarterly Journal Geol. Soc., 1849, vol. vi.

p: 5.

Description.—This species belongs to a limited group of Palw-
oniscr, composed of fishes of small size, remarkable for the large and
flowing form of the dorsal and anal fins, resembling in this respect
the Amblypteri, and restricted (as these are) to deposits of the coal-
measure period. The species under consideration is one of the
smallest of the group, its entire length being not more than 24
inches. The body is fusiform, its greatest depth being immediately
in advance of the dorsal fin, where it measures 7 lines. From this
point it contracts gradually anteriorly, but posteriorly the contrac-
tion is more rapid to the commencement of the caudal fin. The
head is small and slender, occupying less than one fifth of the entire
length. The bones are ornamented with strongly-defined sinuous
ridges. The characters of the opercular apparatus and the mouth
are not shown in the specimen. The pectoral fins are composed of
about ten flattened rays. The anterior margin of the fin is provided
with a delicate fringe of small rays. The other rays have very few
transverse sutures, and do not bifurcate until near their terminations.
The dorsal fin commences a little in advance of the opposite insertion
of the anal fin. It contains about 25 rays, of which the four or five
anterior ones increase in length in succession from before, forming
an ornamental border to the fin. The fifth ray 1s the longest, the

* Poiss. Foss., vol. ii. p. 4.
[ VI. u.]- 6 ¢

9 BRITISH FOSSILS.

two succeeding ones are nearly as long, but the diminution in length
of the remainder is very rapid. They are all strong, and maintain
their size with little variation up to the point where they bifurcate.
The transverse sutures are distant, the larger rays having not more
than five or six, so long as they continue single. The ventral fins
are deficient in the specimen. ‘The anal fin is dislocated, but seems
to have been nearly co-extensive with the dorsal fin. The rays are
shorter, and the diminution in length of the distal ones more
abrupt. The upper lobe of the tail is remarkably long and at-
tenuated, and is invested with small scales to its extremity. The
most distinctive character of the species is found in the scales.
These are large and solid, of rhomboidal form, and covered with
strongly-defined irregular ridges and furrows, the former termi-
nating in sharp cusps on the posterior or free margins The anterior
part of the scale, where it is overlapped by the antecedent scale, is
marked with two or more elevated lines parallel to the outline of
the border of the scale, being probably lines of increment. These
peculiarities are very clearly and faithfully delineated in the mag-
nified view of the scale given in the accompanying plate.

A fiities—Paleoniscus Egertont is most nearly allied to the
species found at Burdie-house, and especially to Palwoniscus
Robisoni.* It is, however, easily distinguished from this species
by the smaller size of the head, the greater depth of the trunk, and
the rugous character of the scales. Palconiscus monensist has not
yet been found entire ; there is nevertheless sufficient evidence in
the detached scales to distineuish 1t from this species. The orna-
ment of the surface is less prominent, and the lines are parallel to
each other, and straight, whereas in Palewoniscus Egertoni they are
irregular and sinuous. No foreign species has the least resemblance
to it.

History.—In 1835,t I communicated to the Geological Society of
London the discovery of numerous remains of fishes in the coal
shale of the Silverdale pits near Newcastle-under-Lyne. They con-
sisted of bones and scales belonging to the genus Megalichthys, then
recently found by the late Dr. Hibbert Ware, at Burdie-house, and
figured in the Transactions of the Royal Society of Edinburgh, § teeth
of Diplodus gibbosus, and scales of a small Palwoniscus, which
were pronounced by Professor Agassiz to indicate a new species of
the genus. Shortly afterwards, my brother, the Rev. W. Egerton,
discovered in the same bed the pretty little specimen represented in

* Agassiz, Pois. Foss., vol. ii. p. 88. + Quart. Jour. Geol. Soc., 1849, vol. vi. p. 5.
{ Proc. Geol, Soc., 1835, § Vol, xiii. pl. 8 and 11.

CES

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BRITISH FOSSILS. 3

the plate, which fully corroborated the accuracy of Professor Agassiz’s
conclusion, founded upon the isolated scales submitted to his ex-
amination. Although the species is recorded in the “ Poissons
Fossiles,” the description of it never appeared, in consequence of the
abrupt termination of that work. The great rarity of tolerably
perfect specimens from the shale-beds of our coal-measures, and the
value of well-marked species in considering the relations of these
beds in one district with those in others, render it desirable to record
a correct figure and description of this species, although it is not a
subject of novelty.

Localities.—Silverdale, near Newcastle-under-Lyne, in a fine, com-
pact, black shale ; highly fissile, with a slightly conchoidal fracture.
Also in Lancashire and Yorkshire, and in some of the Scotch and
Irish coal-fields.

¢

EXPLANATION OF PLATE.

Fig. 1. Paleoniscus Egertoni, natural size.
Fig. 2. Same, magnified twice.
Fig. 3. Scale, magnified ten times.

P. DE M. GREY EGERTON.

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LEPIDOTUS PECTINATUS

B.Forbes dixex’

Egerton.

DECADE 6.PL.3,

LEPIDOTUS
(Oolitic )

IW. Lowr

"BALTISA FOSSILS.

DecaDE VI. Prats III.
LEPIDOTUS PECTINATUS.

[Genus LEPIDOTUS. Aaassiz. (Sub-kingdom Vertebrata. Class Pisces. Order
Goniolepidoti. . Family Lepidostei... Sub-family Lepidoster homocerci. 2d Group. Body
elongated, more or less fusiform.) Dorsal fin opposite the interval between the ventrals
and anal; caudal fin large, with strong fulcral scales on the margins; the base of the
upper lobe invested. with scales ; teeth conical, obtuse; MOBS rhomboidal, large and thick,
invested with a dense layer of ganoine.* | :

Synonym.—Lepidotus pectinatus, EcErton, Proceedings of Geol. Soc.,
1843, p. 184.

Description.—The genus Lepidotus i is one of the most interesting
in the Ganoid order a fishes, in a zoological point.of view, as pre-
senting the best ‘subjects. for the examination of the structure and
development of the singular tegumentary investment upon which
Agassiz established the order, and in other respects as containing
numerous species, easily recognized, frequently i in a good state of pre-
servation, and always characteristic of the age of the strata in which
they occur. Agassiz has described sixteen species in the “ Poissons
Fossiles,” and several new ones have been. discovered since the publi-
cation of his work. I know -few fossils more beautiful than the Lepi-
doti, The large size of some of the species; the rotundity of contour
(so frequently preserved by the rigidity of their dermal encasement
when every vestige of the endo-skeleton and its associated organs has
disappeared to be replaced by indurated mud), the ornamental sculp-
‘turing of the cranial bones, and. above. all; the regularity and
brilliancy of the scales, and the delicate tracery so frequently en-
eraven on the glistening enamel, all combine to render the remains
of this genus most attractive, and little lable to be overlooked by
the most careless observer. The species range from the chalk to the
has inclusive ; one only occurs in the cretaceous series, four in the
wealden, six or seven in the oolites, and eight in the lias. From the
latter formation at Whitby the subject of this article is derived. It
measured, as far as can be calculated from an imperfect specimen,

- * Agassiz, Poiss. Foss., vol. ii. p. 233.
[ VI. 111.] 6D

2 BRITISH FOSSILS.

probably not more than 9 inches in length by 2? inches in depth,
and bears undoubted marks of mature age in the successive lines
of growth engraven on the surfaces of the scales. The head is
imperfect, butefrom what remains it seems to have been longer and
narrower than in Lepidotus minor. A mutilated dorsal and ventral
fin are the only natatory organs preserved. The former is smaller
and less powerfully constructed than is usual in the Lepidoti; the
fulcral scales are shorter and narrower, and the fin rays more arched
than in Lepidotus nunor ; the latter is situate rather nearer the
head than in that species. The trunk is more slender than in any
of the genus, and affords an unmistakeable characteristic of the
species ; but in addition to this we find in the scales such clear
specific indications, that they could be recognized in the most im-
perfect and fragmentary condition. Those on the anterior part of
the body are larger in the vertical than in the longitudinal direc-
tion ; about the flanks these dimensions are nearly equal; while in
the vicinity of the tail the longitudinal diameter is the greatest.
They have the upper border convex, and the lower one concave on
the greater portion of the body, which gives a remarkable undulat-
ing character to the cephalo-caudal series. The dorso-ventral series
are more oblique than in Lepidotus minor, and the joinings of the
scales in the succeeding columns fall nearer the centres of the scales
of each antecedent series. They contain about sixteen scales in
each. These are characterized by delicate radiating striations
which give a pectinated edge to the posterior margin of the scale.
The striations disappear in the caudal region, and the scales are
smooth with entire edges. In the young fish the striato-pectinate
character seems to have existed toa greater extent than in the adult,
as on some of the caudal series zigzag lines are still apparent, which
at one period must have been the free margins of the scales.

A ffinities.—In the proportion and character of the scales this
species approaches the genus Senzonotus.

History.—An unique specimen in the collection of the Earl of
Enniskillen.

Locality.—Lias of Whitby, in Yorkshire.

EXPLANATION OF PLATE.

Fig. 1. Lepidotus pectinatus, size of nature.
Fig. 2. Scales, magnified.

P. DE M. Grey EGERTON.

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E. Forbes, direx *

BRITISH FOSSILS.

DECADE VI. PLATE LV.

PHOLIDOPHORUS PACHYSOMUS.

[Genus PHOLIDOPHORUS. AGassiz. (Sub-kingdom Vertebrata. Class Pisces.
Order Goniolepidoti. Family Lepidostei. Sub-family Lepidostei homocerci. 2d Group.
Body elongated, more or less fusiform.) Dorsal fin small, opposite the ventrals; caudal
fin forked; the lobes equal; the base of the upper lobe invested with scales; teeth
villiform.* ]

Pholidophorus pachysomus, EGERTON.

Description.—This species is easily detected by its stumpy and
inelegant proportions, which contrast strongly with the graceful
forms of the associated Pholidophort. The head bears the propor-
tion of 2 to 7, as compared with the length of the fish to the inser-
tion of the caudal fin, whereas this measurement in Pholidophorus
Bechet is as 1 to 4. The depth of the body at the dorsal fin is
equal to one half of the length from the scapular arch to the tail.
This unusual proportion gives an oval outline to the body, very
distinct from the fusiform shape of the generality of the species.
As compared with Pholidophorus Becher the lower jaw is shorter
and stronger, the orbit larger, and the surface of the opercular
bones léss uneven. The rays composing the pectoral fin are more
slender. The space from the occiput to the insertion of the dorsal
firllMis much less, as is likewise the distance between the ventral
fins and the tail. The other characters of the natatory organs
correspond pretty nearly with those of that species. The scales
are of large size, and perfectly smooth. The series, counting along
the lateral line from the scapular arch to the tail, contain only
30 scales, being 10 less than are found in Pholidophorus Bechet.
Those in the centre of the flanks are the largest. The posterior
edges are curvilinear, and slope rather obliquely backwards and
downwards ; in some specimens they are translucent, in consequence
of the thin plate of ganoine projecting beyond the opaque material

* Poiss. Foss., vol. ii. p. 9.
[VI. iv.] 6 E

2 BRITISH FOSSILS.

of the body of the scale. The articulating processes of the scales ;
are remarkable for their width and strength (Fig. 3.)
A ffinities.—This species most resembles Pholidophorus Bechet.
History.—The description is taken from two specimens in my
possession. Lord Enniskillen has also a specimen of this species.
Locality —F ound in the lias at Lyme Regis.

EXPLANATION OF PLATE.

Fig. 1. The fish, natural size.
Fig. 2. The caudal vertebre.
Fig. 3. Scales, magnified.

P. pE M. GREY EGERTON.

: DEC RD EG or

Geological Survey of the Veiled Rin goat PHOLIDOPEHORUS..
‘ (Oolitic)

PHOLIDOPHORUS CREN UMD Wo Sieg io7e

3 ( ht

4

E. Forbes, Direx *

BRITISH«EOSSih®

DecADE VI. PLATE V.

PHOLIDOPHORUS CRENULATUS.

[Genus PHOLIDOPHORUS. Acassiz. (Sub-kingdom Vertebrata, Class Pisces.
‘Order Goniolepidoti. Family Lepidostei. Sub-family Lepidostei homocerci. 2d Group.
Body elongated, more or less fusiform.) Dorsal fin small, opposite the ventrals; caudal
fin forked; the lobes equal; the base of the upper lobe invested with scales; teeth
villiform.*]

SynonyM.—Pholidophorus crenulatus, EGnRton, Proceedings of Geol.
Soc. 1848, p. 184.

_ Description—tThis is a rare but well-marked species of Pholi-
dophorus belonging to the group of which Pholidophorus Bechet
may be considered the type. In form and proportions it resembles
Pholidophorus latvusculus, but the characters of the scales are
wholly dissimilar. Of the Pholidophori of the lias, described by
Agassiz, one only, namely P. lambatus, has serrated scales. This
structure obtains also in Pholidophorus crenulatus, under descrip-
tion, but it is the only feature common to the two species. The
head is either crushed or wanting in the only specimens I have
seen. It seems to have been smaller in proportion to the entire
length of the fish than in P. Bechet, P. onychius, and P. limbatus.
The coracoid bone is traversed obliquely along its anterior curva-
ture with rounded plaits. The pectoral fins are large, composed of
about 22 rays, slender, and dichotomous in their distal portions.
The anal fin is small. The caudal fin contains from 28 to 30 rays,
with short articulations. The lower lobe is considerably larger
than the upper one. The base of the upper lobe is invested with —
scales, and its upper margin protected by a series of strong imbri-
cated fulcral scales ; these increase in length as they succeed each
other, until they almost rival the true marginal rays of the lower
lobe. The scales present two very distinctive characters. The
anterior portion or base of the scale is marked by a series of parallel,
yertical ridges, extending backwards as far as the articulating pro-

* Poiss, Foss., vol, ii. p. 9.

ivi. ¥. | Gr

z BRITISH FOSSILS.

cess. These are covered by the antecedent scales, and mark the
periodical increment. I have failed to find these evidences retained
in any other species of this genus, although they are permanent in
Paleoniscus, and some other genera. The exposed portions of the
scales are traversed by alternate longitudinal plaits and striations,
radiating at various angles, and increasing in size as they approach
the free margins of the scales. These are slightly thickened, and
distinctly serrated. The number of teeth carried by each scale is
dependent on the number of striz, and these decrease in the more
distant parts of the body. The ventral scales are characterized by
the coarseness of the cusps, and the paucity of the striz. The dor-
sal and ventral fins are as yet unknown ; judging from the frag-
ments preserved in the specimens figured, they probably resembled
these organs in the other species from the lias.

History.—The specimens from which the description is taken are
in my own cabinet.

Locality.—lias of Lyme Regis.

EXPLANATION OF PLATE.

Fig. 1. The fish, natural size.
Fig. 2. Same (young).
Fig. 3, Scales, magnified.
P. DE M. GREY EGERTON.

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Day&5on, Lith™ tp The Queen.

BETISH, FOSSILS.

DecaDE VI. Puate VI.

—_—

OPHIOPSIS BREVICEPS.

[Genus OPHIOPSIS. Agassiz. (Sub-kingdom Vertebrata. Class Pisces. Order
Goniolepidoti. Family Lepidostei. Sub-family Lepidostei homocerci. 2d Group. Body
elongated, more or less fusiform.) Scales uniform in size; caudal fin slightly forked, the
upper lobe invested with scales on the superior margin ; pectoral fins long and large ;
dorsal fin much elongated, and slightly raised; ventral fins opposite the centre of the
dorsal fin; head small; opercular apparatus strong and broad. |*

Ophiopsis breviceps, EGERTON.

Generic Description.—The genus Ophiopsis, as originally defined
by Agassiz (Poissons Fossiles, vol. ii. p. 289), was limited to a
small number of fishes characterized by an extended dorsal fin,
smooth, uniform scales, and a prolonged upper lobe of the dorsal fin.
Subsequently, as we find in the “ Additions et corrections,” vol. ii.
part 2, p. 289, a fish named Ophiopsis Miinsteri was admitted into
the genus, having serrated scales and other features approximating it
to the Pholidophort. In consequence of this extension of the generic
attributes, the boundary line between Ophiopsis and Pholidophorus
becomes very indistinct ; for, while on the one hand we have the
elongated form and extended dorsal fin of the typical Ophiopsis
procerus occurring in Pholidophorus Flesheri, on the other we have
the small head and serrated scales characteristic of several species of
Pholidophorus, cited as distinctive features of Ophiopsis Miimstert.
We find also the uniformity of scales and unequal tail of Ophiopsis re-
presented in Pholidophorus latumanus, tenwiserratus, longiserratus,
and other species of the Oolitic epoch. This is not a fitting oppor-
tunity for entering on the general question of the propriety of re-
arranging the various forms now included in the genus Pholido-
phorus ; as bearing, however, on the subject of the present article,
I may hazard the opinion that if any reliance is to be placed on the
generic characters assigned by Agassiz to Ophiopsis, it must be on
the distinctive features of the dorsal fin; and if so, all the Pholido-
_ phort having extended dorsal fins must be removed from the latter

* Agassiz, Poiss, Foss., vol. ii, part 2, p, 289.
[ VI. vi.] 6G

2 BRITISH FOSSILS.

to the former genus. In tracing the gradation from the narrow
elongated form of the typical Ophiopsides to the shorter and thicker
proportions of the Pholidophori, the little fish described in the fol-
lowing paragraphs, occupies the extreme limit between the two
genera ; the transitional form of Ophiopsis penicillatus completing
the series of that genus. It must, nevertheless, be considered a true
Ophiopsis, since the characters of the dorsal fin and vertebral column
are in strict accordance with that genus, and are of greater value
than the more trivial features in which it resembles some species of
Pholidophorus.

Description.—Ophiopsis breviceps is a small fusiform fish, mea-
suring 4 inches in length by 1 in depth. The head occupies only one
fourth of the entire length. The vertebral column extends in a direct
line from the head to the commencement of the caudal fin, without
any curvature in the thoracic and abdominal regions. The bones of
the head and gill-covers are ornamented with a pattern rather
coarser than is usual in so small a fish. The mouth is large, and well
furnished with small, conical, sharp teeth. The pectoral fins resemble
those of the Pholidophori. The ventral and anal fins are small, and
approximate to each other. The dorsal fin commences in advance
of the ventral fins, and extends beyond the insertion of the anal
fin. Itcontains nearly forty rays. The upper lobe of the tail is
larger than the lower one, and is invested with scales for some dis-
tance, giving a heterocerque character to the organ. The scales are
small and rhomboidal. The upper margins are concave, the lower
ones convex. The enamel appears thicker on the margins of the
scales, causing a slight depression of the central area. The posterior
edges are strongly serrated over the whole body.

A ffinities—The generic affinities have been already alluded to.
The species is very distinct from all with which I am acquainted.

Locality.—Lowest beds of the Lower Purbecks in Wockly, or
Oakleigh quarry, near Tisbury.

History —tThe figures and description are taken from the speci-
mens in the collection of the Museum of Practical Geology, the only
ones I have seen of this species.

EXPLANATION OF PLATE.
Fig. 1. 2. The fish, natural size.
Fig. 3. Scale, magnified.
Fig. 4. Tail of a larger individual.*

P. DE M. Grey EGERTON.
* This may be Ophiopsis penicillatus,—Agassiz, Poiss. Foss., vol. ii. p. 290,

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BRITISH FOSSILS.

DercADE VI. Puate VII.

PTYCEOLEPIS MINOR.

[Genus PTYCHOLEPIS. Acassiz. (Sub-kingdom Vertebrata. Class Pisces. Order
Goniolepidoti. Family Sauroidei. Sub-family Sauroidei homocerci. Ist Group. Tail
forked.) Scales thick, elongated, plicated transversely on the base, and deeply furrowed
longitudinally on the enamel; under surface smooth, and devoid of rib; pectoral fins
pointed ; dorsal fin opposite the ventral fins; ana! fin remote. |

Ptycholepis minor, EGERTON.

Description.—The genus Ptycholepis has hitherto been restricted
to a single species, Ptycholepis Bollensis, remarkable for its occur-
rence in several widely-separated localities, viz., Whitby in York-
shire, Lyme Regis in Dorsetshire, and Ohmden, in the kingdom of
Wurtemburg. Being in possession of a fine series of specimens
from each locality, Iam enabled to amend the generic characters
formed by Agassiz on imperfect materials. The pectoral fins when
perfect are pointed rather than rounded at their extremities, and
of moderate size. The dorsal fin is more remote than Agassiz ima-
gined, being situate nearly as far back as in Hugnathus, and the
anal fin is nearer to the tail than to the ventral fins. A very dis-
tinct character obtains in the under surface of the scales, not found
in Lugnathus, or the allied genera. In these a projecting rib occurs,
traversing the middle of each scale, produced to a point, at the upper
margin, and recessed at the lower, for the reception of the corre-
sponding ,process of the adjoining scales; but in Ptycholepis the
under surface is level, and the articulation is effected by an angular
process of the upper margin of the scale, adapted toa notch in
the lower margin of the succeeding scale. The specimen under de-
scription belongs undoubtedly to this genus, although the small size
of the fish and its general outline recal at first sight the features of
a Pholidophorus. The total length of the fish, including the tail, is
4 inches, of which the head occupies one fourth part ; the greatest
depth is 10 lines; this point occurs immediately behind the gill-
covers, from whence the body diminishes gradually to the base of

[VI vii] weer ae he 6 H

2 BRITISH FOSSILS,

the tail. The bones of the head are marked with irregular, pro-
jecting lines at distant intervals, interspered with small isolated
tubercles. The opercular bones are similarly ornamented, but
the intervals between the lines are rather larger. A few scales im-
mediately behind the scapular arch, on the central part of the body,
are of large size. These are traversed by five or six longitudinal
sinuous furrows, and terminate with a serrated margin. They are
succeeded by scales more elongated, and having fewer and more
regular furrows, and these on the dorsal, ventral, and anal regions
give place to the narrow elongated scales (fig. 5.) peculiar to this
genus. All the scales have their bases,—or those parts overlapped
by the antecedent scales,—marked by parallel, transverse plicee, show-
ing the periods of growth. In this character they resemble the
scales of Pholidophorus crenulatus, and some Palewonisci. The pec-
toral fin is broad at the base, and pointed at the termination. It is
composed of about 30 rays. The transverse articulations of the rays
are frequent near the base, but very distant in the other portions of
the fin. The dorsal, ventral, and anal fins are wanting. The tail
is small and elegantly forked. The articulations of the rays are
more numerous in the lower than in the upper lobe, but the intervals
between them become greater as they recede from the base. In
these respects this organ has considerable resemblance to the caudal
fin of Pholidophorus. The endo-skeleton in this genus was pro-
bably entirely cartilaginous, since I have been unable to discover in
any specimen the least trace or impression of the spinal column or
its appurtenances.

A ffinities.—The genus Ptycholepis is considered by Agassiz to be
most nearly allied to Hugnathus. This opinion is founded upon the
characters of the scales and teeth. The latter I have not been able
to detect in my specimens. In other respects it has considerable
resemblance to the Pholidophori, and especially to some of the
narrow-scaled species of that genus, which I have proposed to remove
to the new genus Histionotus. These features, together with the
absence of a bony endo-skeleton, which is of considerable solidity in
Eugnathus, lead me to infer that the Ptycholepides were altogether
more feeble and less predatory than the Sawroid genera, with which
they are allied.

Locality—The specimen above described was found in the lias
quarries at Barrow-on-Soar, and is the only example of this species
IT have met with. The two halves are in the possession of Lord
Enniskillen and myself.

BRITISH FOSSILS.

EXPLANATION OF PLATE.

Fig. 1. Fish, natural size.

Fig. 2. Counterpart of same.

Fig. 3. Scales from the flank.

Fig. 4. Scale near the scapular arch.
Fig. 5. Scale near the tail.

P. pE M. Grey EGERTON.

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BRITISH FOSSILS.

DecaDE VI. Puate VIII.

—— =

LEPTOLEPIS MACROPTHALMUS.

[Genus LEPTOLEPIS. Acassiz. (Sub-kingdom Vertebrata. Class Pisces. Order
Goniolepidoti. Family Sauroidei. Sub-family Sauroidei homocerci. 1st Group. Tail
forked.) Scales very thin and rounded; dorsal fin opposed to the ventrals; operculum
broad; sub-operculum large; teeth villiform; lower maxillaries with strong coronoid
processes. |

Synonym.—Leptolepis macropthalmus, EGERTON, Journal of Geol. Soc.,
vol. i. p. 231.

Generic Description.—In the year 1844, I communicated to the
Geological Society a brief account of this and some other fossil fishes
then recently discovered in the Oxford clay, at Christian Malford ;
but as no figure of this species is given in the Journal of that Society,
and as I have since had the advantage of examining a larger number
of specimens from the same locality, disclosing additional characters,
I have thought it an appropriate subject for this decade. Before
commencing the description of the species, I must allude to some
anatomical details common to the genus, which have induced me to
make some alterations in the generic characters assigned to it by
Agassiz. He describes (Poiss. Foss., vol. 11. p. 13.) the teeth to be
“en brosse, en avant des machoires; de plus grosses dans leur
partie postérieure ;” and at part 2, p. 129, “Ils ont des machoires
armées de dents coniques, absolument comme les Sauroides.” After
a careful examination of more than 100 specimens in my own
cabinet, I have entirely failed to detect any trace of the conical
teeth alluded to in the foregoing quotation. I am, consequently,
inclined to believe that the teeth in this genus were exceedingly
minute, so much so as to have perished in most cases with the in-
tegumentary investment of the jaws. The only allusion to the teeth
in the specific descriptions of the Leptolepides in the “ Poiss. Foss.” is
to this effect : “ Les dents ne sont visibles qu’a la machoire inferieure ;
mais elles sont si petites, que ce sont presque des dents en brosse.”
This entirely coincides with the result of my own examination, and

[VI. viii.] 6 I

yi BRITISH FOSSILS.

is, I think, corroborated by the general form of the mouth, which I
now proceed to describe. This organ is entirely bounded by the
premaxillary (figs. 1, 2, 6.) and lower maxillary bones. The former
are very long, reaching, when the mouth is shut, as far back as the
orbit ; they are scimitar-shaped, the curve being backwards and
upwards. The lower maxillaries are remarkable for having, at one
third distance from the symphisis, a strong ascending coronoid pro-
cess (figs. 1, 2, 3, a.) expanded at its upper extremity, and rising
nearly at right angles from the dentary bone. In front of this
process the bone is thickened out into a table, corresponding with a
similar thickening of the proximal ends of the premaxillaries, and
well adapted for the support of a cushion of minute villiform teeth.
When the mouth is slightly open, the gape is defined by the anterior
part of the premaxillaries, and that portion of the lower maxillary
in advance of the coronoid process, and is nearly vertical ; but when
fully expanded the long premaxillary bones sweep forwards as far
as the symphisis of the lower jaw, carrying with them a broad
fold of integument, and forming a cavity nearly equal to the dia-
meter of the entire head. The great length of the lower jaw behind
the coronoid process provides the means for this enormous expansion
of the oral orifice. This singular conformation of the lower jaw oc-
curs in the Caps and some of the allied Cycloid fishes of the present
day. That Agassiz is correct in arranging Leptolepis in the Sauroid
rather than the Lepidoid family, I have little doubt ; for on com-
paring it with other genera, I find that the allied genus Thrissops
has also a coronoid process, though of smaller dimensions, with distinct
Sauroid teeth, while the genus Pholidophorus, which is liable to be
confused with Leptolepis, has the lower jaw of a very distinct form.

Description.—This species of Leptolepis is the most slender and
elegant of the genus; the head partakes of the graceful character
of the general form, being narrow and elongated. Its component
bones are thin and perfectly smooth, with the exception of the pre-

operculum, which is characterized by coarse striations, radiating from .

its anterior margin. The orbit is large, but not so large (compared
with other species) as 1 conceived to be the case when I gave the
name to the species. The spinal column contains about 40 vertebree ;
the terminal ones decrease rapidly in size, and trend slightly upwards.
The ribs and the other vertebral apophyses are slender. The pectoral
fins contain about 12 rays. The ventral fins are situated nearly in the
centre of the body, and are comparatively large, containing each
from 10 to 12 rays. The dorsal fin is small, and is directly above
the ventrals. The anal fin is also small, and placed about mid-way

Sek apes nae
aoa

BRITISH FOSSILS. =

between the ventral and caudal fins. The latter organ is sym-
metrical ; it has eight rays in the upper lobe, springing from the
terminal vertebra, and three or four marginal rays above. The
lower lobe has from eight to ten rays. The scales are small and
very thin, finely sculptured with delicate, concentric striz on the
enamelled surface. This species differs from the following in its
more elongated proportions and the relative small size of the head,
as well as in the form of the centrum of the vertebree.

A ffinities.—The generic relations of Leptolepis are with Thrissops
and Megalurus. Professor Miiller considers the recent Ama to be
a living representative of this section of the Ganoid order, and pro-
poses to group them as a family of his Ganoidei holostei. The
affinities of the species have been alluded to in the description.

Locality and Geological Position—tThis fish appears not un-
common in the Oxford clay, at Christian Malford, associated with
several other species of fossil fish, and with the cephalopodal remains
so remarkable for the rare conservation of their more perishable
parts.

EXPLANATION OF PLATE.

Fig. 1. Fish, the size of nature. a. coronoid process. 6. premaxillary.

Fig. 2. Specimen with the mouth open. a. coronoid process. 6. premaxillary.
Fig. 3. Specimen showing the under part of the head. a. a. coronoid processes.
Fig. 4. Scales, magnified.

P. pt M. Grey EGERTON.

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BRITISH FOSSILS.

DECADE VI. | PuatTe IX.

LEPTOLEPIS CONSTRICTUS.

[Genus LEPTOLEPIS. Acassiz. (Sub-kingdom Vertebrata. Class Pisces. Order
Goniolepidoti. Family Sauroidei. Sub-family Sauroidei homocerci. Ist Group. Tail
forked.) Scales very thin and rounded; dorsal fin opposite the ventrals; operculum
broad; sub-operculum large; teeth villiform; lower maxillaries with strong coronoid
processes. }

Leptolepis constrictus, EGERTON.

Description.—The genus Leptolepis contains no fishes of mag-
nitude, nevertheless, as some of the species are very minute,
the range of size is considerable. Leptolepis constrictus holds an
intermediate position in this respect. The largest of four specimens,
which I have examined, measures 34 inches from the extremity of
the nose to the fork of the tail. The head is small, occupying less
than one fourth of the entire length, and of elegant form. Indeed,
the whole fish is remarkable for the graceful proportions it displays.
The bones of the head are exceedingly thin, and quite smooth, with
the exception of the preoperculum, which is characterized by a fan-
like group of prominent ridges, radiating from the anterior angle of
the bone. This structure distinguishes the species very neatly from
Leptolepis concentricus,* which has the preoperculum as smooth as
the other cranial bones. The mouth is small, and opens upwards.
The lower jaws are curved. No teeth are visible in the specimens
I have seen, which, in other respects, are in a good state of pre-
servation. The coracoid bone is strong and rounded. The spinal
column consists of 38 vertebree. These are longer than broad, and
are remarkable for the depth of the constriction of the centrum
between the articulations. Hence the specific designation. This
constriction gives to each vertebra the form of an hour-glass. The
relative position, size, and character of the fins in this genus vary
little. In the species under consideration they are all small, and
the rays slender. The pectorals contain about 19 rays in each fin,

_ * Egerton, Journal of Geol. Soc., vol. v. p. 35.
[VL 1x.] 6K

v4 BRITISH FOSSILS.

the ventrals 10, and the dorsal and anal 12. The caudal fin is
bifurcate, the lower lobe being rather larger than the upper. The
scales are oval, and their surface marked by numerous fine concen-
tric lines, as in all the other species of the genus.

Afinities—This species is distinguished from Leplolepis concen-
tricus by the sculptured preoperculum, the greater tenuity of
the scales, and the smaller size of the head. It has some resem-
blance to Leptolepis Knorri, found at Solenhofen, but has the
head proportionately larger, the apophyses of the caudal vertebree
less inclined, and the form of the vertebree very distinct. I havea
specimen of Leptolepis, found in a hassic bed near Curcy in France,
which very much resembles this species.

Locality. All the specimens I have seen of this species belong to

Mr. Moore, and were found by him in a bed of light-coloured las

near Ilminster.

EXPLANATION OF PLATE.
Fig. 1. The fish, natural size.
Fig. 2. Another specimen.
Fig. 3. Scales, magnified.

P. pE M. Grey EGERTON.

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BRITISH FOSSILS.

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LOPHIOSTOMUS DIXONI.

[Genus LOPHIOSTOMUS (ogios, lophius, croua, os). EGrrton. (Sub-kingdom
Vertebrata. Class Pisces. Order Goniolepidoti. Family Sauroidei. Sub-family Sau-
roidei homocerci.) Body short and thick; head depressed; mouth large, dehiscent ;
premaxillary and maxillaries with a single row of large, conical, incurved, grooved teeth ;
smaller teeth on the vomer and palatines ; divided nasal; lower jaw deep, with an outer
row of stronger and an inner row of weaker teeth; glossohyal expanded into a broad
plate; scales rhomboidal, ganoid, pitted on the surface and serrated at the posterior
margin. |

Species un1cA.—Lophiostomus Dixoni, EGrRrton.

Description.—In order to convey an adequate idea of this singular
fish, it has been necessary to exceed the limits of illustration generally
adopted in this publication. The two plates, from the masterly
hand of Mr. Dinkel, contain four views of the specimen, together
with magnified representations of the scales and teeth. The num-
bers used to designate the various bones are those employed by
Professor Owen, in his writings on the homologies of the Vertebrate
skeleton. It is not in this respect only that I am indebted to my
distinguished friend ; I have also to acknowledge the invaluable as-
sistance he has afforded me in working out the details of this curious
fossil, and his recognition of its affinities to the recent Arapaivma.
In form this fish was short, squat, and bulky, contrasting remark-
ably in these respects with the more or less elongated features of the
abdominal predatory fishes, both recent and fossil, and recalling
rather the similitude of a Siluroid. The head is wide and flat-
tened, and measured probably more than a fourth of the entire
length. The muzzle is broad and semicircular, projecting somewhat
beyond the lower jaw ; the gill-covers are large, and the branchi-
ostegous rays of great strength. All these bones are invested with a
dense layer of ganoine, having the surface raised into innumerable
small prominences more or less confluent or distinct, resembling in
this respect some recent Silwroids and fossil Ganoids. The frontal
bones (Plate x*, fig. 11) form a large, somewhat triangular plate,

[Vir et es] 6 L

2 BRITISH FOSSILS.

expanded towards the occiput, and bearing two remarkable promi-
nences behind the orbits. Behind and beneath this projection, on
the right side, is seen a strong process extending downwards and
backwards (fig. 8). This, from its form and position, must be
the mastoid bone; although, from the obliteration of all sutures, it
is impossible to determine whether it is not partially composed of
the postfrontal. Immediately in advance of the frontal bones are two
small semilunar bones (fig. 15) corresponding to two semicircular
emarginations of the anterior edge of the frontal plate, and two
recessed facets of the premaxillary bone (fig. 22). With respect to
these bones, Professor Owen writes as follows :—‘‘ I am now satis-
fied, from the way in which the bones or divided bone fit into the
emarginations of the frontal, that they are the nasals, answering to
the similarly divided but more elongated nasal of Lepidosteus.” In
following up this view the correctness of the identification becomes
evident on examining the corresponding parts in the genera Poly-
pterus and Amia, where we find the long narrownasals of Lepidosteus
represented by bones very similar in form to those of the fossil
under consideration. External to these bones are two small ossicles
(fig. 19), occupying the position of the “nasaux” of Cuvier. These
are the turbinals of Owen, and correspond closely with these bones
in the recent Anva calva. Several fragments of bone (fig. 73) occur
between the turbinals and the upper maxillary, apparently belong-
ing to a large lachrymal or suborbital bone. Immediately behind
the upper portion of this bone a recess in the frontal bone marks the
position of the orbit, and attests the absence of the supraorbitals
which surround the orbit in Lepidosteus. The area of exposed chalk
between the orbit and the preoperculum may have been occupied by
a large postorbital plate, as in Arapaima and Ama. The upper jaw
is composed of a single cuneiform premaxillary and of large arcuate
maxillary bones, as in Arapavma (Plates x., x*, figs. 21,22). Hach
of these components supports a single row of long, sharp, conical
teeth, very regular in size, incurved at the points, and fluted on the
surface. Within there is a second row of similar teeth, but rather
smaller in size; the central ones are situate on the vomer (Plate x.,
fig. 13), and the lateral ones on the palatine bones (Plate x., fig. 20).
The lower jaw is composed of long and broad dentary bones (Plates
x., x*, fig. 32), with small articular ossicles (fig. 30) at the con-
dyloid extremities. The teeth are of like character with those of the
upper jaw, and equally regular, but they are implanted in a double
row ; those constituting the outer row being considerably larger than
the secondary ones. The operculum (Plate x*, fig. 35) is of moderate

BRITISH FOSSILS. 3

size and of triangular form, narrow above and broad below,
as in Lepidosteus. The suboperculum (fig. 36) is long and nar-
row, and joins the operculum on a horizonal line. In front of this
the remains of a small inter-operculum occur (fig. 37). The opercular
apparatus is completed by a moderately-sized slightly curved pre-
operculum (fig. 34). This bone corresponds with the other bones of
the head in superficial character, and is not, as is frequently the
case, distinguished by a more bold and radiating style of orna-
mentation. The hyoidean arch is characterised by the great
strength and expanse of its component parts. The ceratohyal bone
(Plates x., x*, fig. 40) is flat and curved, and expands below into
a broad spatula. It supports a series of 10 or 12 short falciform
branchiostegals (fig. 44), the lower ones being shorter and broader
than those which precede them. They partake of the enamelloid
character common to all the other bones of the head. The most
remarkable feature in the anatomical structure of this region, is to
be found in the disproportionate development of the glossohyal or
lingual bone, which is here expanded into a broad, oval disc, mea-
suring 14 inch in length by 1 inch in width (Plate x., fig. 42), and
occupying the entire space beneath the rami of the lower jaw when
the mouth was closed. The position of the broad articular extre-
mities of the ceratohyals, with reference to this plate, leads to the
inference that it derived its support from these bones without the
intervention of the basihyals. It is, however, very possible that
the latter may either be confluent with the ceratohyals, as in the
conger eel, or may support the base of the glossohyal plate. The
scapular arch is for the most part concealed, but enough remains to
show that it partook of the massive proportions of the adjoining
parts. The scapula (Plate x*, fig. 51) is short and of great width,
being flattened out into the resemblance of an operculum. It is
smooth on the surface, a feature peculiar to this bone. The supra-
scapula (fig. 50) is smaller than the scapula, and of more slender
proportions. The lower extremities of a pair of strong coracoid
bones are seen in Plate x., fig. 52. The pectoral fin is unfortu-
nately mutilated ; enough, however, remains to indicate an organ of
singular aspect and powerful proportions. It contained 10 or 11
rays of great strength, diminishing in size from first to last. They
are invested with a dense coat of ganoine, composed of rugged imbri-
cate tubercles, similar to those on the bones of the head, but much
coarser ; the rays are very close set, and are of like character ; the
first, although the largest, not exhibiting any distinctive features,
such as are frequently found in some recent families. The appear-
612

4 BRITISH FOSSILS.

ance in the plate of a series of carpal bones is deceptive, and is due
to a fracture of the base of the fin and the removal of the cuter sur-
face of the rays. The ventral fins are abdcminal, and situated very
near the pectorals. They are comparatively small, containing four
rays of similar appearance to the pectoral rays, but of slighter form.
They are supported upon two pubic bones, of which the distal
extremities only are preserved (Plate x., fig. 63.) The scales con-
stitute a peculiar and valuable feature in considering the affinities of
this fish, a subject which will be treated in the sequel. The dorsal
and lateral series are for the most part absent, and the few that re-
main are inverted; the ventral scales, however, are in perfect state
of preservation. They are quadrilateral, and more or less acutely
rhomboidal, as in Lepidosteus and most of the fossil Ganoids. They
have a thick superficial layer of dense, lustrous ganoine, deeply and
irregularly pitted and grooved on the surface, and terminate pos-
teriorly in an uneven and coarsely serrated margin. The upper
anterior corner of the root of the scale is produced to an acute angle,
while the lower corner is rounded off to fit the corresponding angle
of the succeeding scale. This compact adaptation of the adjoining
scales to each other is still further secured by an articulating process
on the upper margin of each scale lodging in a corresponding de-
pression in the lower margin of the next in the series. This arrange-
ment is identical with that in many of the genera of the fossil
Ganoids, and obtains also in the recent Lepidosteus. It is much to
be regretted that no other portions of this fish have been preserved,
since the position, form, and structure of the dorsal and caudal fins,
and the character of the vertebral column are most important ele-
ments in determining its true character in relation to the other
members of the class to which it belongs.

A finities—The generic title I have adopted for this fish has no
reference to any real or supposed affinities with Lophius ; it has
been suggested solely by the disproportionate size of the mouth, so
remarkable in both. In general features Lophiostonvus is so unlike
any fish, either fossil or recent, with which I have been able to
- compare it, that it must for the present be considered an isolated
form. It possesses, nevertheless, some resemblances in structural
details, both to fossil and recent forms, which point to an approxi-
mation of its true position in the scale of nature. With respect to
the order to which this singular fish should be referred, there is
fortunately no doubt. Thanks to the labours of the talented author
of the Agassizian system, a single scale is decisive of its being a
true Ganoid. Again, the association of the rhomboidal scale, with

BRITISH FOSSILS. 5

large predatory teeth, stamps it a member of the Sawroid family.
As compared with other fossil members of this family, it approxi-
mates Hugnathus in the character of the scales, but differs from this
genus and resembles Caturus in the uniformity of the teeth. Be-
fore I was cognizant of the scales, I was inclined to think it might
belong to the Celacanths. The bulky form and depressed head, the
broad lower jaw, fluted teeth, and sculptured bones, are all features
prevalent in that family ; but the angular scales forbid this associa-
tion, as the boundaries of these families are now defined. There
are certainly exceptional forms among the fossil Sawroids, such as
Megalurus and Leptolepis, with rounded scales, but these are com-
bined with other characters preponderating in favour of the Sauroid
relationship. On comparing Lophiostomus with recent fishes, the
most striking features which naturally suggest themselves are the
dentigerous maxillaries, the divided nasal, and the expanded lingual
bone. The first peculiarity, namely, the part performed by the
maxillary bone in the conformation of the upper jaw, is common to
the Clupeide, the Salmonide, to Lepidosteus, and Polypterus, and
to several genera of doubtful position, such as Arapaima,* Anvia,
Hyodon, Megalops, Erythrinus, Macrodon, &c. Most of these
genera have also teeth on the vomer and palatine bones. The
divided nasal is a structure of more limited occurrence. It obtains
in Lepidosteus, Polypterus, Amia, Araparma, Heterotis, Krythrinus,
as also in Megalichthys, and some other fossil genera. The lingual,
or submaxillary plate, the glossohyal of Pofessor Owen, occurs in
Llops, Megalops, and Amia, but attains its maximum development
in Arapaima. Among fossil genera, A sterolepis has this bone single ;
in Holoptychius and some of the Dipterians it is double as in
Polypterus, while in M egalichthys and Osteolepis it is replaced by
three plates. The combination of these features most in accordance
with those in Lophiostomus occurs in the genera Arapaima and
Amia. In reference to the former, Professor Owen wrote to me from
Paris last autumn as follows: “ Having your chalk fish still in view,
I looked sharp at all the fishes’ skulls at the Garden of Plants, and
found almost its fac-simile in that of the great Sudzs (Arapaima)
gigas ;—the same short premaxillaries, long dentigerous maxillaries,
rear rank of shorter teeth on the vomer and palatines, divided nasal,
broad glossohyal, numerous branchiostegals, and rough outer surface
of the bone, &c.; the general shape much closer to the fish from
Alfriston than the skull of Lepidosteus is, but clearly showing the
same Sauwroid or Salamandroid family construction.” In some

* Vastres, Cuvier and Valenciennes.

6 BRITISH FOSSILS.

respects the resemblance to Amia is also very remarkable, especially
in the form and proportions of the divided nasal, and the turbinal
bones, in the position of the orbit, the shortened antero-posterior
dimensions of the cranium, the larger size of the teeth, and the
absence of the deep pits characteristic of the head bones in Arapaima.
The flattened head resembles that of Polypterus, and the scales and
operculum those of Lepidosteus.

To recapitulate the peculiarities of Lophiostomus: it has the
scales of a Ganoid, and the teeth of a Sawroid, associated with
characters found in Arapaima and Amia, but differing from all
these in outward form and proportions, and in these respects
approximating rather to the family of the Celacanths. It would
be premature to attempt, from a single specimen, and that an
imperfect one, to unsettle established generalizations, without suf-
ficient materials to prepare a sound basis of re-adjustment. It
is, however, clear that when the period arrives for a re-classification
of many genera, both recent and fossil, now occupying somewhat
doubtful positions, the subject of this description must form an
essential element in the consideration. Cuvier has placed Lepidosteus
and Polypterus, Amia and Avrapaima, with the Clupeide ;
Agassiz considers the two former as Sauroids, the two latter,
Celacanths ; while Miiller places Arapaima with the Cluperde,
and creates a new order, Ganoidei holostei, for the families
Lepidosteini and Polypterini, and suggests a third family for the
reception of Ama, combined with the fossil genera, Megalurus,
Leptolepis, Thrissops, and their allies. This is not the place to
enter upon a discussion of the many points raised in such a con-
troversy, but we must hope that before long Professor Agassiz, who
is now so opportunely located for studying some recent forms im-
plicated in the question, may be able to effect a ee settle-
ment of these disputed points.

History and Geological Position.—The only specimen I have
seen of this fish is in the British Museum. It was found in a chalk
quarry near Alfriston, in Sussex, and was presented to the National
Collection by Captain Beckford, R.N., of Ryde. JI am indebted to
my friend, Dr. Mantell, for the drawings of the specimen, made
some years ago by Mr. Dinkel; and, in accordance with his wishes,
I have named the species after the late Mr. Dixon, a tribute I am
too happy to make to the memory of one whose friendship I long
enjoyed.

se

BRITISH FOSSILS.

IXPLANATION OF PLATES.
PLATE X.

Fig. 1. Lophiostomus Dixoni, under view.
Figs. 2. 3. Teeth, magnified.

Figs. 4. 5. Upper surface of scales.

Fig. 6. Under view of scale.

PLATE X*.
Fig. 1. Lophiostomus Dixoni, side view.
Fig. 2. Ditto ditto front view.
Fig. 3. Ditto ditto | upper view.

REFERENCE TO FIGURES.

8. Mastoid bone. 36. Subopercular.
11. Frontal. 37. Interopercular.
12. Postfrontal. 40. Ceratohyal.
13. Vomer. 41. Basihyal.

14. Prefrontal. 42. Glossohyal.
15. Nasal. 44, Branchiostegal.
19. Turbinal. 50. Suprascapular.
20. Palatine. 51. Seapula.

21. Maxillary. 52. Coracoid.

22. Premaxillary. 57. Phalanges.
23. Articular. 63. Pubic.

32. Dentary. 69. Ventral fin.
34. Preopercular. 73. Suborbitals.

35. Opercular.

P. pE M. Grey EGERTON.

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These Sections are arranged, in the form of Vertical Columns, to a scale of 40 ft. to an inch, and illustrate such de
it is impossible to give in the Horizontal Sections above described. In the Coal Measure Sections, for instance, the Th
of each Bed of Coal, the Mineral Structure and Thickness of the Strata with which they are associated, and the ki

Amount of Ironstone, are given in the greatest detail. Sheets 1 to 18, price 3s. 6d. each Sheet.

we!

MAPS OF IRELAND.

InDEX Map? of CaRLow, sacs iccanaen | coloured, price 7s. INDEX MAP of WEXFORD, Geo A dt
Do. KILDARE, 0. 7S. Horizontal Sections to WIcKiL: ye Ds.e
Do. WICKLOW, do. 78. Plan and Sections of the Ovoca i+ S 9
Do. DUBLIN, do. 7S. ik

BOOKS Published under the Superintendence of the Geological Survey and Museum of Practical Geolo

REPORT on CORNWALL, DEVON, and WEST SOMERSET. By Sir H. T. Dz La Bucus, F.RS. &c, 8vo. 14s.
FIGURES and DESCRIPTIONS of the PALHOZOIC FOSSILS in the above Counties. By PRorESSOR PHILLIPS.

THE MEMOIRS of the GEOLOGICAL SURVEY of GREAT BRITAIN, and of the MUSEUM of ECONOMIC GEC
of LONDON. 8vo. Vol. I. 21s.; Vol. II. (in 2 Parts), 42s.

BRITISH ORGANIC REMAINS. Forminga portion of the Memoirs of the Geological Survey. Decades I. II. III.
ie VII. and VIII. with 10 Plates each. yal 4to. 4s. 6d.; or royal 8vo. 2s. 6d. each Decade.—Other DECADES are
VES. . Dieu,
RECORDS of the SCHOOL OF MINES and of SCIENCE applied to the ARTS. Vol.I. PartI. Inaugural and Introc
Lectures to the Courses for the Session 1851-52. Royal 8vo. price 1s. 6d. cloth. Vol. I. Part Ii. On the oy
South Staffordshire Coalfield. By J. BreTE JuKEs, M.A., F.R.S., &c. Price 2s.6d. Vol. 1. Part Iii. On the.
Wicklow and Wexford. By Warineton W. SmyTu, M.A., &c. Vol. 1. Part IV. Statistics of the Produce of (
Tin, Lead, and Silver from the Mines of the United Kingdom, with the Exports and Imports of these Metal:
1848 to 1852 inclusive. By ROBERT Hunt, F.R.S., Keeper of Mining Records. : bea ayes ona
CATALOGUE of SPECIMENS in the Museum of Practical Geology, illustrative of the Composition and Manu:
_of British Pottery and Porcelain. By Sir HENRY DE LA ‘Broun, and TRENHAM REEKs, Curator. &
Woodcuts. Price 1s.. : : Col eerste ag
MEMOIRS of the GEOLOGICAL SURVEY and of the MUSEUM of PRACTICAL GEOLOGY. “MINING RECC
MINERAL STATISTICS for 1853-1854, embracing the produce of Tin, Copper, Lead, and Silver for both ye
Iron; of Coals and other Minerals for 1854 ; the Exports and Imports; the Population employed, and a J
the Collieries of the United Kingdom. By Roprrr Hunt, F.R.S., Keeper of Mining Records. — a

These Maps, Sections, and Books may be obtained at the Museum of Practical Geolo
Jermyn-street, London. en

at

N.B.—TZo prevent the confusion arising from different titles, as above, all further publications will appear wn
general title of “MEMOIRS OF THE GEOLOGICAL SURVEY, and of the Museum of Practical Geology ;” the
* Decades,” “ Mining Records,” “ Reports,” &ec. being employed as subordinate titles, as im the last work of the li

July 20,1855. *, RODERICK I. MURCHISON, Director-Gen

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