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PALHONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVILI.

LONDON:
MDCCCLXXVIII.

THE OOLITIC ECHINOIDEA.

DIRECTIONS TO THE BINDER.

The Monograph on the Oolitic Echinoidea will be found in the volumes of the Paleontographical
Society for the years 1855, 1856, 1857, 1858, and 1878.

Cancel the title-pages affixed to the separate parts for the years 1855, 1856, 1857, and 1858, and
substitute that provided in the volume for 1878. Cancel also page 155 in the volume for 1855, and
page 303 in the volume for 1856. Place the “ Additional Notes on Bibliography ” (unpaged), bound in
the volume for 1858, between pages 449 and 451.

ORDER OF BINDING AND DATES OF PUBLICATION.

PAGES | PLATES ISSUED IN VOL. FOR YEAR PUBLISHED
1—iV | — 1878 March, 1878
v—x a 1855 February, 1857
1—154 I—xX 1855 February, 1857
155—302 XI—X XII 1856 April, 1858
303—390 | XKXITI—XXXVI 1857 November, 1859
391—468 XXXVII—XLIII 1858 March, 1861
469—481 — 1878 March, 1878

Vv P
vert
Tae MONOGRAPH

lg} i }

ON THE

Piebriskh FOSSIL

ECHINODERMATA

OF

THE OOLITIC FORMATIONS.

BY

THOMAS WRIGHT, M.D., F.R.S. EDIN., F.G.S.,

VICE-PRESIDENT OF THE PALHONTOGRAPHICAL SOCIETY ; CORRESPONDING MEMBER OF THE ROYAL SOCIETY OF SCIENCES
OF LIEGE ; THE SOCIETY OF NATURAL SCIENCES OF NEUCHATEL; VICE-PRESIDENT OF THE COTTESWOLD
NATURALISTS’ FIELD CLUB; CONSULTING SURGEON TO THE CHELTENHAM HOSPITAL;

AND MEDICAL OFFICER OF HEALTH TO THE URBAN SANITARY DISTRICTS

OF CHELTENHAM, CHARLTON KINGS, AND LECKHAMPTON.

VOLUME I—THE ECHINOIDEA. 7
SMITHSON AR f
JUL 18 1986

LIBRARIES

baits LONDON:

PRINTED FOR THE PALZONTOGRAPHICAL SOCIETY.
1857—1878.

4 PRINTED BY s

J. B, ADLARD, BARTHOLOMEW CLOSE.
’ reat py

INTRODUCTION.

I vetavep the Index to my Monograph on the Oolitic Echinoidea in the
hope that after the publication of the Fourth Part some new species from time to
time would be discovered in our Jurassic rocks, and thereby have necessitated a
Supplement to the work. Up to the present time I have waited for new forms in
vain ; and, as numerous inquiries have been made for the index, my most kind and
considerate friend, our worthy Secretary, knowing how much my time is occupied
with important public duties, kindly offered to prepare the same, and the members
of the Paleontographical Society owe to the Rev. Thomas Wiltshire, M.A.,
Sec. G.S., their thanks for the full and well-classified Index which accompanies

this sheet.

In taking a retrospective glance at the progress of the Monograph it is very
satisfactory to find that so little remains to be added to the Oolitic species of
Hehinoidea described and figured therein; and indeed, as far as I am aware,
nothing requires to be retracted from any of its pages. It has been my constant
endeavour throughout the many years I have been engaged in its composition to
do ample justice to all naturalists who, either as contemporaries or as predecessors,
have been engaged in the study of the interesting groups of fossil forms included

in the class Echinodermata.

Since I commenced this Oolitic Monograph several very important works have
enriched this branch of Paleontology. In France my learned friend M. Gustave
Cotteau has published ‘Etudes sur les Hchinides fossiles du Département de
VYonne.’ The first volume contains figures and descriptions of all the species
in the Terrain Jurassique, and the second volume is dedicated to the Cretaceous

species, which I shall notice in due course in my Memoir on the Kchinoids from
a

il INTRODUCTION.

the Cretaceous Formations now nearly completed. Associated with the late
M. Triger, M. G. Cotteau has published with admirable plates his ‘Hchinides du
Département de la Sarthe,’ a work which includes both Jurassic and Cretaceous
species. M.G. Cotteau has also published a series of papers in the ‘ Revue et
Magasin de Zoologie’ on “‘ Hchinides nouveaux ou peu connus,” containing many
rare forms of Jurassic species, and several other important memoirs on

Hechinoderms from other formations.

In Switzerland my learned friend M. H. Desor published in 1858 his valuable
‘Synopsis des Wchinides fossiles,’ illustrated with an atlas of well-executed plates
(this work being a revised and enlarged edition of the ‘Catalogue raisonné des
Wchinides’ by Agassiz and Desor); and, in conjunction with my learned friend
M. P. De Loriol, he issued the large work entitled ‘ Hchinologie Helvétique,’
containing accurate descriptions and excellent figures of all the species of

Echinoidea found in the Jurassic rocks of the Alps.

M. P. De Loriol has followed up this important national work with a second
volume, comprising the “Hchinides” of the Cretaceous period, to which I shall

refer in detail on a future occasion.

In Germany Professor Quenstedt, of Tiibingen, has published figures and
descriptions of all the species of Hchinoderms from the Jurassic rocks of his
country, some of which previously had been so beautifully figured in the

‘ Petrefacta Germanize’ of Goldfuss.

The Kchinology of different Jurassic regions of Germany has had able
exponents. Thus, Dr. Gustav C. Laube has contributed a memoir on ‘ Die
Hchinodermen des Braunen Jura von Balin ”’ with beautiful plates ; Dr. W. Dames
has given “Die Hchiniden der nordwestdeutschen Jurabildungen’ with plates.
The latter is an important contribution to the Paleontology of this region, as
showing how closely allied the north-western Oolites of Germany are with those of

England.

M. De Loriol has enriched the ‘ Description Géologique et Paléontologique des

Ktages Jurassiques supérieurs de la Haute-Marne’ by MM. EH. Royer and H.

INTRODUCTION. il

Tombeck, with descriptions and figures of all the ‘“‘ Wchinides”’ found in the upper
stages of this Department; and my learned friend has likewise made a similar
contribution to the ‘Monographie Paléontologique et Géologique des Etages
supérieurs de la Formation Jurassique des Environs de Boulogne-sur-Mer,’ par
P. De Loriol et H. Pellat; and in the ‘Monographie Paléontologique and
Géologique de l’Htage Portlandien du Département de l’Yonne,’ par P. De Loriol
et G. Cotteau, we have a combined work of much value, showing the correlation of

our Portlandian series with that of France.

It is evident from this brief review that the last twenty years has been a period
of great Paleontological activity throughout Europe, and it is gratifying to find
that our own Society has contributed its mite to the general progress of knowledge
relating to the Echinoderms of the Oolitic formations of the British Islands.

THOMAS WRIGHT, M.D., F.R.S.E.

4, Sv. MarGaret’s Trreack, CHELTENHAM ;
16th January, 1878.

+ dla ite kdl Hs

PALAONTOGRAPHICAL SOCIETY.

INSTITUTED MDCCCXLVII,

LONDON:

rs

y

ie oo

Bahl aii

A MONOGRAPH

e

ON THE

Pitti ish FOSSIL

ECHINODERMATA

OF

THE OOLITIC FORMATIONS.

BY

THOMAS WRIGHT, M.D., F.R.S.E.

PART FIRST,

CONTAINING

THE CIDARIDA, HEMICIDARIDA, AND DIADEMADA.

LONDON:
PRINTED FOR THE PALHZONTOGRAPHICAL SOCIETY.
1855.

aa

PREFACKH.

In presenting the First Part of my Monograph on ‘ British Fossil Echinodermata’ to
the members of the Paleeontographical Society, I deem it necessary to make a few remarks
in order to explain—l1st, how I came to occupy the position of an author in the magnifi-
cent volumes published by your Society; and 2dly, to state the manner in which I have
endeavoured to discharge the duties of the task I have undertaken.

After the publication of my ‘ Memoirs on the Echinodermata of the Oolites,’* in the
‘Annals of Natural History,’ my much lamented friend, the late Professor Edward Forbes,
as a member of your Council, asked me to contribute a Monograph on the same subject
to the Palezeontographical Society. Knowing that he had in preparation a supplementary
chapter on the Echinoderms of the Great Oolite, for Messrs. Morris and Lycett’s
Monograph on the Mollusca of that Formation, I thanked him for the good opinion he
had formed of my ability for such a work, but declined, lest, by complying with his request,
I might possibly have interfered with any intentions of his own on the subject, knowing
how ardently he loved all that related to this class of the Animal Kingdom. As Professor
Forbes, however, on another occasion, renewed, in the most pressing manner, his solici-
tation, I then proposed to join him in a Monograph on the British Fossil Echinodermata
of the Secondary Formations, which he at once agréed to, and the proposal for this joint
work was submitted to the approval of your Council, and received its sanction.

The numerous and constantly increasing duties of my esteemed colleague at the School
of Mines prevented him from taking any share in the collection of materials for the prepa-
ration of the Monograph on the Oolitic Echinodermata, and, with his usual candour, he
told me that, as he was unable, from want of time, to contribute to this division of our
proposed joint work, his name must be withdrawn from its title page; and, if agreeable to
me, that I should undertake the Monograph on the Oolitic species, whilst he would devote
himself to the description of the Cretaceous forms. After this arrangement, I directed my
attention with redoubled energy to the subject of my special studies.

On his appointment to the chair of Natural History in the University of Edinburgh,
Professor Forbes took with him the materials for the first part of his promised Monograph

* «Annals and Magazine of Natural History,’ new series, vol. viii, 1851.

vi PREFACE.

on the Cretaceous Echinoderms; but, alas! his untimely and much-lamented death pre-
vented him from even commencing that work upon which his mind had been so long and
busily engaged, and which was looked forward to with so much interest by all who
knew the high qualifications of my friend for his selected task. But the mysterious decrees
of Providence disappointed our expectations, and at the same time deprived Natural Science,
in this country, of one of its brightest ornaments and warmest advocates. It would be
doing violence to my own feelings if I did not, on this occasion, record the high estimation
in which I held the opinions of my distinguished colleague on all points relating to the
work we had undertaken together, and the uniform deference I paid to his suggestions, as
to the best mode of executing the same, which were always dictated by that kindness,
frankness, and wisdom so characteristic of the man.

Having been thus thrown entirely on my own resources, before the real difficulties
of the work began, I have experienced more than ever the deep responsibility of the
task I have undertaken. I trust the circumstances I have narrated will entitle me to
the consideration and indulgence of all who know the nature and amount of the
difficulties to be grappled with in a work like that in which I am engaged, and the
time and labour necessary to overcome them. I can only add, that I have spared neither
time, labour, nor research, in order to make this Monograph worthy of the confidence
originally reposed in me; but how far I may have succeeded in my efforts, it remains for
others to decide.

At the suggestion of my excellent friend, Thomas Davidson, Hsq., author of the
magnificent Monograph on the Brachiopoda, and several other kind friends interested in
the success of this work, it was thought advisable that, at the conclusion of my Monograph
on the Oolitic species, I should proceed with the description of the Cretaceous forms, in
order that a greater unity in the arrangement and management of the subject might be
observed in the two Monographs on the Echinodermata of the Secondary rocks; and a
proposal to this effect has been submitted to your Council, and received its sanction.

I have ventured to propose some important alterations in the classification of the
Hchinoidea, and lave grouped the genera into thirteen natural families, many of which
are entirely new. My object has been to attain a more natural method, and thereby
facilitate the study of the different groups. I have given an analysis of these families at
the commencement of the work, and enumerated the most common types of each.

In the description of the species, I have taken them in their stratigraphical order,
always commencing with the species found in the oldest rock in which the genus is
discovered, thus — a, Lias, Lower, Middle, and Upper; 4, Inferior Oolite; ce, Great Oolite,
including Fullers-earth, Stonesfield Slate, Great Oolite, Bradford Clay, Forest Marble, and
Cornbrash; d¢, Oxford Clay; e, Coralline Oolite, including Calcareous Grit, and Coral
Rag; /, Kimmeridge Clay; g, Portland Oolite; 2, Purbeck Beds ;—so that my work has
the double advantage of being stratigraphical and paleontological at the same time, a
mode of treating the subject which I hope will prove useful and convenient to geologists.

PREFACE. vil

Many of the readers of this Monograph will probably be surprised to find some old
generic names reproduced, which have long been superseded by those of modern writers ;
but a sense of justice to such authors as Van Phelsum, Breynius, Klein, and Leske, has led
me to consult their original works, and restore the genera first described and figured by
them, but omitted from the treatises of later authors on the same subject. In the nomen-
clature of the Echinodermata, had I merely gone back to the time of Linneeus, as suggested
by the committee of the British Association in their report made in 1842, I must necessarily
have excluded the important work by Breynius,* in which, for the first time, were proposed
seven well-described and accurately figured genera of Hchinoidea, which, by some strange
oversight, were not adopted by his contemporaries, although they have reappeared under
new names in the works of later authors. On the principle of priority, therefore, I have
restored the original genera so clearly defined by Breynius, even although it may occasion
a temporary inconvenience in the names of some well-known forms of urchins.

In every case, where practicable, the name of the author who either first recorded,
described, or figured the species, follows the specific name of the object, without the
addition of “Sp.” adopted by some authors. By this mode justice is done to the original
author, and confusion avoided. ‘The modern practice of inventing and changing generic
names, and appending to the old specific name that of the individual who has merely
changed a name, but discovered nothing, cannot be sufficiently discountenanced, as it
greatly increases the confusion arising from an already overloaded synonymy, and thereby
retards the real progress of the natural history sciences.

The accurate determination of species, and their distribution in time and space, form
problems of the highest importance to the paleontologist, as their true solution are the
only certain guides of the geologist in his investigations in the field, and his generalizations
in the study: for the classification of strata, the subdivision of rock groups, and the
boundary lines between different formations, are all points which are more or less affected
by the soundness of his conclusions.

In determining the species of Echinodermata, therefore, the most careful comparison
has been made with the true type forms to which they are referred, and the extent of
the section in the description of the species, on the affinities and differences exhibited by
each with other Foreign and British congeneric forms, will show how much care has been
taken to arrive at a correct determination. )

The range and stratigraphical position of the species described in this work has
occupied much time and attention, as many errors found in previous lists of Oolitic
Echinodermata required considerable research to correct ; for experience has taught me
that, unless the palzeontologist can verify for himself the statements of his collectors, he
will frequently be led into similar errors. In every instance, with the exception of
the Northamptonshire beds, which have been carefully noted by my friend the

* De Echinis et Echinitis, sive Methodica Echinorum distributione, Schediasma. Gedani, 1732.

Vill PREFACE.

Rev. A. W. Griesbach, I have visited the different localities given in this work, and with my
own hammer ascertained the presence of the species in the rock whence they are stated to
be obtained; the most perfect confidence may therefore be placed in the notes on the
stratigraphical distribution of the species, as the greatest care has been taken in order to
arrive at the truth.

As the Oolitic rocks of Europe were deposited in basins of greater or less extent, it
follows that many contemporary species which lived on different shores of these ancient
seas will, from time to time, be discovered; and Foreign species, hitherto found only in
the Oolitic rocks of the Continent, will doubtless be discovered in strata of the same age
in England, and vice versd. I have, therefore, at the end of the description of the species
of each genus, for the purpose of easy reference in the event of new species being found,
appended original notes on Foreign Oolitic species of that genus most nearly allied to
our own forms, but which have not as yet been found in the English Oolites. ‘The
Foreign species are printed in a different type, and the notes are placed at the end of the
section to which they belong. ‘The short diagnosis I have given of each species is drawn
from authentic specimens kindly contributed by several distinguished foreign friends,
whose names are mentioned in connection with their specimens. A reference is made to
the best figures of each species extant; and for the localities in which they are found, and
the collections in which the types are contained, I have consulted with much advantage
M. Desor’s excellent ‘Synopsis des Echinides Fossiles,’ now in course of publication.

It is now my pleasing duty to return my most sincere thanks, either for the loan of
specimens, or permission to inspect their collections in quest of new forms, to Mr. Pickering
and Mr. King, Malton; Mr. Charlesworth, York; Mr. Waite and Mr. Duck, Calne; Mr.
William Buy, Sutton; Mr. Bean, Scarborough; the Hon. Mr. Marcham; Mr. H. C.
Sorby; Mr. W. Cunnington, Devizes; Mr. Walton and Mr. Bush, Bath; Mr. Mackneil,
Wotton-under-Edge; the Rev. P. B. Brodie, Rowington Vicarage, near Warwick; Mr.
John Lycett, Minchinhampton; Mr. John Jones, Gloucester; Professor Buckman and Mr.
Bravender, Cirencester; Professor Morris, Professor Tennant, and Mr. J. S. Bowerbank,
London; Mr. W. M. Tartt, Mr. Charles Pierson, Mr. Thomas Bodley, and Mr. Edward
Hull, F.G.S., Geological Survey, Cheltenham.

I beg to tender my especial thanks to the Rev. A. W. Griesbach, of Wollaston,
for several valuable contributions, consisting of many fine series of different species of
Hchinoderms from the Great Oolite, Forest Marble, and Cornbrash of Northamptonshire,
likewise for the labour he has bestowed in finding some rare species, and ascertaining
many valuable facts relative to the distribution of the species found in his county; to
Mr. J. Graham Lowe, Kensington Park, for the gift of Pygaster wmbrella, Lamk., from
the Coral Rag; and to Mrs. Lowe for the gift of the rare <Asterostoma excentricum,
Agass.; to Dr. Symes, Bridport, for a fine Clypeus Agassizit, from the Inferior Oolite of
Chideock ; to Mr. Charles Moore, Bath, for the gift of some rare specimens from the

PREFACE. 1X

Upper Lias of Ilminster; to Mr. Etheridge, Bristol, for several rare urchins; to Mr. G. HE.
Gavey, C.H., for the donation of several fine Crinorpna and Astrroip#a, from the Middle
Lias of Chipping-Campden, and for the loan of his finest specimens for figuring in this
work ; to the Harl of Ducie, for the loan of his unique Solaster Moretonis, Forbes, and
several fine Cretaceous Cidaris and Star Fishes; to Mr. John Leckenby, Scarborough,
for much useful information relative to the distribution of the Yorkshire Oolitic Echinoder-
mata, and for the gift of several specimens; to Dr. Murray, Scarborough, for the
donation of several rare Coralline Oolite Pygasters and Pygurz, collected by him at Ayton ;
to Mr. Reed, York, for much valuable information regarding the Whitwell beds of
Inferior Oolite, and for the gift of type specimens of Pygaster semisulcatus, Phil., and
Echinus germinans, Phil.; to Mr. Wood, Richmond, Yorkshire, for the gift of fine
specimens of Echinobrissus orbicularis, Phil., Echinobrissus dimidiatus, Phil., and
Woodocrinus macrodactylus, de Koninck, and for kindly placing his beautiful collection of
CrinormpEA at my disposal; to Mr. Charles Fowler, Cheltenham, for the gift of Cidaris
Fowleri; to Mr. Davidson, of Brighton, for the uniform interest he has taken in the
success of this work, for the specimens he has contributed, the manuscript plates he has
lent, and the introductions he has given me to several distinguished Continental naturalists,
who have kindly supplied much useful information.

I desire to make my warmest acknowledgments to M. Michelin, of Paris, who possesses
the finest collection extant of living and fossil Echinodermata, for the magnificent series of
type specimens he most generously contributed to my cabinet for comparison with English
forms ; to M. Bouchard-Chantereaux, of Boulogne, for a series of Echinoderms from the
Oolitic rocks of the Boulonnais ; to M. Cotteau, of Coulommiers, for the types of the
species described by him in his ‘tudes sur les Echinides Fossiles du département de
YYonne;’ to M. 'Triger, of le Mans, for a suite of specimens collected by him from the
Oolites in the departement de la Sarthe; to Professor Deslongchamps, of Caen, for the
specimens collected by him from the Oolites of Calvados, and determined by M. Agassiz ;
to M. de Loriére, of Paris, for many rare urchins from the département de la Sarthe; to
Professor Roemer, for the types of several of his brother’s species from the Oolites of
Hanover ; to Dr. Fraas, of Stuttgart, for the types of many of Count Miinster and Professor
Goldfuss’s species from the Royal Museum of Wiirttemberg; to Professor de Koninck, of
Liege, Dr. Oppel, of Stuttgart, and M. Seemann, of Paris, for good types of many
Foreign species.

My warmest thanks are likewise due to my friend Mr. S. P. Woodward, of the British
Museum, for kindly acting as my referee in the prosecution of this work, and for the many
valuable suggestions he has made during its preparation and progress, as well as for the
assistance he has given me in comparing my specimens with Foreign types in the British
Museum, and aiding in the determination of dubious forms.

The late Sir Henry de la Beche, Director-General of the Geological Survey of Great
Britain, most liberally gave me free access to all the specimens contained in the Geological

x PREFACE.

Museum in Jermyn Street; and the same privilege has been most kindly renewed by his
distinguished successor, Sir Roderick I. Murchison, to whom I beg to tender my warmest
acknowledgments. [am under many obligations to my friend Mr. Waterhouse, of the
British Museum, for his kindness in allowmg me to examine all the Echinoderms in the
National Collection, and his permission to figure those I have selected for this purpose.
Professor Sedgwick, of Cambridge University, at my request, most liberally communicated
the types of Professor M‘Coy’s new species of urchins, described in the ‘Annals of Natural
History.’ Mr. Rupert Jones has at all times given me free admission to examine the rich
cabinets of the Geological Society of London. Professor Phillips, of Oxford, has afforded
me much useful information relative to the species of Echinoderms first figured in his
valuable work on the ‘Geology of Yorkshire.’ To each of these kind friends I beg to
tender my most grateful acknowledgments.

My best thanks are likewise especially due to Messrs. Bone and Baily, for the great
care they have bestowed on the beautiful plates that enrich my Monograph, which, for
scientific accuracy in details, and artistic effect in execution, are second to no lithographs
of similar objects extant.

THOMAS WRIGHT.

Exeter Piace, CHELTENHAM;
August, 1856.

A MONOGRAPH

ON THE

FOSSIL ECHINODERMATA

OF THE

OOLITIC FORMATIONS.

Sus-Kinepom—RADIATA.

Txts great division of the Animal Kingdom includes classes which differ widely from
each other in form, organization, and habits. Some have the body circular, globular, or
ringed ; or vermiform, plant-like, or amorphous. Some are enclosed in a soft arachnoid,
transparent membrane, and float like crystal masses through the water, as the Jnfusoria and
Acalephe ; others hang like living stalactites from the roofs of submarine caverns, like the
Amorphozoa ; or, assuming the forms of the Vegetable World, they develope ramose stems,
with numerous branches, of which myriads of zoophytes are at once the builders and
inhabitants, as the Polypifera. Some are enclosed in exquisite shells, microscopic in size,
but unrivalled in symmetry, although the structure that produces them is but a mere film
of jelly, as the Foraminifera ; others have a complicated calcareous skeleton, composed of
many thousands of separate elements, which, for beauty and contrivance, is unsurpassed by
that of any other class, as the Echinodermata. Where the nervous system has been dis-
covered, it consists of a simple gangliated filament, surrounding the entrance to the
digestive organs; but in by far the greater number of animals grouped in this division,
no distinct nervous system is found, although the creatures themselves possess an exquisite
sensibility.

The sub-kingdom Raptata is formed of classes which are more remarkable for their

1

2 RADIATA.

negative than for their positive characters: hence it wants that unity of composition so
well displayed in the sub-kingdoms Mounusca, Arricutata, and Vrrteprata, Some
naturalists have proposed to separate the RapiaTa into two sections, under the names
Aneura and Cyclo-neura, or Acrita and Nemato-neura ; but, unfortunately, the nervous
system of only a very few genera of the Cyclo-neura is known, so that, by generalizing
too much upon these isolated facts, we are in danger of reasoning on an error in order
to establish a method.

We include in the sub-kingdom Rapiata the six following classes, which may,
for the sake of convenience, be subdivided into two sections ;—in the one, the form of the
body is more or less globular, sometimes it is symmetrical, often it is regular or amor-
phous,—these form the Guopunar Raprata. In the second section the body is stellate,
and the divisions are arranged in the form of rays around a common centre,—this stellate
form can often be shown to consist of a bilateral symmetry. ‘These classes form the
STELLATE Rapiata. The following table exhibits the sections and classes, to which
are added the names of typical genera as examples of each :

Sub-Kingdom. Sections. | Classes. Examples of Genera.
f 1. AMORPHOZOA Halichondria, Spongilla, Spongia.
Globular Radiata \ 2. FoRAMINIFERA Orbitoides, Nummulites, Rotalia.
les INFUSORIA Plesconia, Dileptus, Paramecium.
RaDIata. P : :
4, POLYPIFERA Alcyonium, Oculina, Meandrina.
Stellate Radiata / 5. AcaLEPHm® Medusa, Physalus, Cassiopeia.
6. ECHINODERMATA Encrinus, Asterias, Echinus.
|

Crass—ECHINODERMATA.

The name Ecurnopermata was given by J.T. Klein, in 1734,* to the shells of Sea-
urchins, which were called Echini. Bruguiéret subsequently called that class which com-
prised the Star-fishes, and the Sea-urchins, Hcuinoprrmata. Cuvier included in his
class EcHINODERMES, with Asterias and Hchinus, the Holothuria, animals that are destitute
of the prickly skin, of the more typical forms, and have many external affinities with some
Mollusca; and subsequently, in his ‘ Regne Animal,’§ he grouped in this class, Zes Echino-

dermes sans pieds, forming the order Sipunculoidea, which connect the Radiata with the
Annelidous Articulata.

* ‘Naturalis Dispositio Echinodermatum,’ Jacobi Theodori Klein, 1734.
+ ‘Tableau Encyclopédique des trois Régnes de la Nature,’ 1791.

t ‘Tableau Elementaire de l Histoire naturelle des Animaux,’ 1798.

§ ‘Regne Animal distribué d’aprés son Organisation,’ 1834.

ECHINODERMATA. 3

The Echinoderms are most highly organized animals, and for the most part are covered
with a coriaceous integument. In several orders it is strengthened with numerous calcareous
pieces, which together form a complicated skeleton. The external surface of the skin, in
many families, developes spines of various forms and dimensions, which aid in locomotion,
and serve as defensive instruments to the creatures possessing them. By far the largest
number of these animals have a complicated system of vessels for the circulation of water
through their bodies. These aquiferous canals are intimately connected with the locomotion
of the animal; for by means of it, most of the typical groups put in motion those remark-
able suckers which protrude in rows from different divisions of the body. In the Eehinoidea
they escape through the holes in the poriferous zones, and in the Asteroidea they pass
through apertures in the intervals of the small plates which form the middle of the rays,
whilst in the Sipunculoidea these organs are altogether absent.

No class of the Animal Kingdom more clearly exhibits a gradation of structure than
the Hehinodermata ; for, whilst some remain rooted to the sea bottom, and in this sessile
condition and other points of structure resemble the Polypifera, others exhibit the
true rayed forms, clothed in prickly armour, which characterise the central groups of this
class. These conduct us, through a series of beautiful gradations, to soft elongated organisms,
whose forms mimic the Asccdian Mollusca ; whilst others have the long cylindrical body
and annulose condition of the skin, with the reptatory habits of the Apodous Annelida.

With so fertile a field for investigation, it is not surprising that the minute anatomy
of the Echinodermata should have engaged the attention of some of the most distinguished
Naturalists of our age—iedemann, Miller, Van Beneden, Agassiz, Desor, Forbes, and
Sharpey,—and have yielded fruits which the physiologist reckons as among the most
marvellous contributions to morphological science.

The class Echinodermata is divided into eight orders, which, in descending sequence,
may be thus arranged :

1. SIPUNCULOIDEA. | 5. OPHIUROIDEA.
2. HoLOoTHUROIDEA. 6. BLASTOIDEA.
3. ECHINOIDBA. 7. CYSTOIDEA.
4, ASTEROIDEA. 8. CRINOTDEA.

Order 1. Srpuncunorpza—form the apodal Annelidous Echinoderms; they have a
long cylindrical body, divided into rings by transverse folds of the integument: they have
no tubular suckers, nor calcareous parts in their body, nor is it divided into a quinary
arrangement of longitudinal lobes: some have horny bristles, like the feet of many Annelida,
which they somewhat resemble : their mouth is sometimes surrounded by tentacula, which
are not, however, regulated by a definite number, nor disposed with the same regularity
as in the next Order. They are unknown in a fossil state.

Type. Stpunculus edulis. Cuv. Pallas.

4 ASTEROIDEA.

Order 11. HonornuroipEa.—Body in general elongated; skin usually soft and
leathery, in a few genera strengthened by calcareous or horny spines. Five avenues of
suckers, which divide the body into as many longitudinal, nearly equal, lobes or segments ;
mouth surrounded by plumose tentacula, the numbers of which are in general multiples of
five ; anus at the opposite extremity of the body ; digestive organs consist of a long intestine,
which makes some coils in passing through the body; respiration performed by internal
ramified tubes, like a miniature tree; locomotion effected by contractions and extensions of
the body, and by rows of tubular suckers, similar to those in the Star-fishes and Sea-urchins.
The softness of their naked integument prevents their preservation in the stratified rocks.
We know none in a fossil state.

Type. Cucumaria Jrondosa. Griiner.

Order 111. Ecutnorpza.—Body spheroidal, oval, or depressed, without arms; furnished
with a distinct mouth, sometimes armed, which is always below, and an anus which
occupies different positions. Body enclosed in a shell or test, composed of twenty columns
of calcareous plates, and ten rows of holes for the passage of retractile tubular suckers ;
the surface of the test is studded with tubercles, which possess, jointed with them, moveable
spines, of various sizes and forms in the different families and genera: at the summit of
the test is the apical disc, composed of five genital plates, perforated for the passage of the
ovarial and seminal tubes, and five ocular plates for lodging the five eyes. The intestine
winds round the shell, attached by a mesentery, the surface of which, as well as the mem-
brane lining of the test, is covered with vibratile cilia.

Type. ‘The common Sea-urchin, Hehinus sphera. Miller.

The HcowinoipEa are represented by one family in the Paleozoic rocks, and by
numerous families in the Mesozoic and Tertiary rocks, several of which characterise these
great periods of geological time. ‘They likewise abound in our present seas.

Order 1v. AstERoiprA.—Body stelliform, depressed, provided with five or more lobes
or hollow arms, which are a continuation of the body, and contain prolongations of the
viscera; the mouth, which is always below and central, serves likewise as an anus; rows
of retractile tubular suckers occupy the centre of the rays. Skeleton complicated, com-
posed of numerous solid calcareous pieces, variable as to number, size, and disposition ;
skin coriaceous, studded with calcareous spines of various forms; a madreporiform plate on
the upper surface, near the angle between two rays; eyes placed at the extremity of the
rays ; reptation performed by the tubular suckers.

‘Type. The common Star-fish, Uruster rubens. Linnzus.

This order is represented in the Silurian rocks by two genera. The Oolitic, Cretaceous,
and Tertiary rocks contain many extinct forms. The existing species are very abundant
in all the present seas.

ECHINODERMATA. 5

Order v. OpHivroipEA.—Body discoidal, distinct, depressed, provided with long,
slender arms, in which there is no excavation for any prolongation of the viscera; they
are special organs of locomotion, and independent of the visceral cavity; they have spines
developed from their sides; the mouth, surrounded by membranous tentacula, is always
below and central, and serves at the same time as the anus. Skeleton complicated, com-
posed of calcareous pieces, of which the size and number vary in different genera. The
arms, long and slender, are sustained internally by central vertebral-like pieces, but they
are not hollow or grooved underneath, as in the Asterozdea: they are special organs of
locomotion, independent of, and superadded to, the visceral cavity, and have numerous
plates or spines regularly disposed along their sides to assist in reptation.

Type. The common Sand-star, Ophiura teaturata. Lamarck.

This order is represented by one genus in the Silurian rocks. Several genera are
found in the Oolitic, Cretaceous, and Tertiary rocks, as well as in our present seas.

Order vi. Buasto1pra.—Body in the form of an oval calyx, composed of solid, cal-
careous plates, provided with five interambulacra and five ambulacra, the latter united su-
periorly, striated. transversely, and having a deep furrow down the middle ; ten ovarial holes,
opening into five at the summit, and a central mouth aperture ; a short, slender stem; but
the body is destitute of arms.

Type. Pentremites inflatus. Sowerby. Carboniferous Limestone.

The genera are all extinct, and belong to the Palaeozoic rocks. One species appertains
to the Upper Silurian, six to the Devonian, and twenty-four are special to the Carboniferous
rocks.

Order vir. Cystorpra.—Body more or less spherical, supported on a jointed stem ;
the bursiform calyx is formed of close-fitting polygonal plates, varying in number in the
different genera, and investing the surface like a coat of mail, except above, where
there are three openings, one for the mouth, one for the anus, and one with a valve for
the reproductive organs; the fourth aperture is below, and is continuous with the canal
in the stem. Some have two or four arms, others are armless; certain species possess
articulated tentacula, and curious comb-like appendages, or pectinated rhombs, in connec-
tion with the plates.

Type. Pseudocrinites quadrifasciatus. Pearce. Upper Silurian.

This order is extinct. All the genera are found in the Silurian and Devonian rocks.

Order vitt. Crino1pra.—Body bursiform, distinct, formed of a calyx composed of a
“definite number of plates, provided with five solid arms, which are independent of the
visceral cavity, and are adapted for prehension; a mouth and anus distinct ; no retractile
suckers ; ovaries at the base of the arms opening into special apertures. Skeleton compli-

6 ECHINOIDEA.

cated, calcareous, composed of thick plates closely articulated together, the number and
arrangement of which are determinate in the different families, the multiples of five being the
numbers which predominate; the central plate of the body is supported on a long, jomted
column, which is firmly rooted to the sea-bottom. The mouth is central and prominent ;
the anus is situated at its side; the arms are mostly ramose and multi-articulate, and when
extended form a net-like instrument of considerable dimensions. ‘The mouth is always
placed upwards, and retained in that position by the column being jointed to the central
plate of the calyx. The normal station of the Crinormna is the reverse, therefore, of the
AstERoIDBA and HvunINoIDEA.

Type. Pentacrinus Oaput-meduse. Miller. From the seas of the Antilles.

Extinct families of Crinoids have existed in-all seas from the Silurian downwards, and
one or two representatives are now living.

From the above analysis of the class HoninopErMAta, it appears that, as the Spuncu-
loidea and Holothuroidea are not found in a fossil state, and the Blastoidea and Cystoidea
are special to the Palzeozoic period, our field of investigation in this Monograph is limited
to the Ecu1norpza, AstEROIDEA, OpHiuroipEA, and Crinomea, which we now propose
to consider seriatim, commencing with the HcHrnorpEa.

Order—EcHINOIDEA.

The body is spheroidal, oval, depressed or discoidal, and is enclosed in a calcareous
test or shell, composed of ten columns of large plates, the inter-ambulacral areas: and ten
columns of small plates, the ambulacral areas, which are separated from each other by ten
rows of holes, constituting the poriferous zones. The external surface of the plates is
studded with tubercles of different sizes, in the different families; these are articulated with
the spines by a kind of moveable ball-and-socket joint: the spines are of various forms
and dimensions, and serve well to characterise the genera and species.

At the summit of the test is the apical disc, composed of five genital plates, perforated
for the passage of the ovarial and seminal canals, and five ocular plates, notched or perfo-
rated for lodging the eyes. ‘There are two great apertures in the test, one for the mouth,
and the other for the anus; the relative position of these oral and anal apertures varies in
the different families, and forms an important character for their systematic classification.

The mouth is sometimes armed with a complicated apparatus of jaws and teeth, but
sometimes it is edentulous. The internal organs of digestion consist of a pharynx, cesopha-
gus, stomach, and intestine, which winds round the interior of the shell, attached thereto by
a delicate mesentery, its surface, as well as that forming the lining membrane of the shell,
is covered with vibratile cilia, the play of which causes currents of sea-water to traverse

ECHINODERMATA. 7

incessantly the interior of the body, and to perform an important part in the function of
respiration ; their blood is circulated in arteries and veins, aided by a central pulsating
organ or heart. ‘The five ovaries and testicles occupy the ambulacral divisions, and open
externally through the holes in the genital plates. Their locomotion is effected by the
joint action of the tubular retractile suckers and the spines. Many sea-urchins attach
themselves to rocks by these tubular feet, and some bury themselves in limestone, and
sandstone or even in granitic rocks, by the abrading action of the spines.*

The nervous system consists, according to M. Van Beneden, of a circular cord, which
surrounds the entrance to the digestive organs, and sends branches into the divisions of
the body. Professor Agassiz, and the late Professor Edward Forbes, regarded the organs
situated in the ocular plates as eyes, but M. Dujardin+ denies them even a nervous system.
In the absence of a greater amount of direct anatomical evidence on the point, the follow-
ing observation, related by M. Alcide d’Orbigny,{ has an important bearing on the
question, and supports it affirmatively.

Captain Ferdinand de Candé, who commanded the ‘ Cléopatre’ in the Chinese seas,
told M. d’Orbigny that he had captured, on their coasts, an urchin with long spines,
probably a Diadema, which he examined in a vessel of water. ‘I hastened to seize it,” he
observed, “when it instantly turned all its spies m the direction of my hand, as if to
defend itself.

“Surprised at this manceuvre, I made an attempt to seize it on the other side, when
immediately the spines were directed towards me.

“T thought from this that the urchin saw me, and that the motion of the spines was
intended as an act of self-defence; but, to prove whether this movement of the animal

* M. Eugéne Robert exhibited to the Academy a block of old red sandstone, obtained from the shore
of the great Bay of Douarnenez, which was perforated with numerous holes, evidently formed by the
Echini which were lodged in them. Hach rounded cavity is in exact proportion, both as to size and form,
with the body of the Echinoderm. M. Lory, Professor at Grenoble, and well known for his numerous and
excellent works on geology, has begged me to exhibit several specimens of perforating Hchini, which have
taken up their abode in the granite of the Bay of Croisic, not far from Piriac. It isthe same granite as that
from the Pouliguen, and in the same state of alteration. This igneous rock is there perforated by Mollusca
and Echinodermata for an extent of several kilometers. Those which M. Lory has just discovered are
certainly of the same species as the Echini which burrow in the old red sandstone of the Bay of Douarnenez.
They closely resemble the Mediterranean Echinus, mentioned by Lamarck under the name of Echinus lividus.
It is one of the most abundant Echini on the coast, and in the market of Marseilles, whence Lamarck
obtained his specimens. I have never heard that these individuals possessed perforating habits; and
probably a careful examination of living specimens of the Echinus from the coast of Brittany may show
that it belongs to a distinct species, notwithstanding its apparent identity with that of the Mediterranean.
In this case it might be called Hehinus terebrans. ‘Observations on Hehini perforating the Granite of
Brittany,’ by M. Valenciennes.—Comptes Rendus, Nov. 5, 1855, p. 755.

+ Lamarck, ‘ Animaux sans Vertébres,’ 2d ed., tom. iui, p. 200.

t ‘Paléontologie Francaise Terrains Cretacés,’ tow. vi, p. 12.

8 ECHINOIDEA.

was produced by my approach, or merely by the agitation of the water, I repeated the
experiment very slowly, and even over the water with a stick: the urchin, whether in
the water or out of it, having always directed its defensive spines towards the object which
approached it. From these observations I arrived at the conclusion that these urchins see,
and that their spines serve them as defensive instruments.”

It is worthy of remark, that Captain Candé, at the time he watched this urchin, was
ignorant of the anatomical fact that eyes had been detected in the Echinide, and his
inference was simply the legitimate conclusion drawn from carefully-made observations.

The calcareous test of the Echinoidea is the only part of the structure of these animals
which is preserved in a fossil state. It has hitherto failed to attract that amount of
attention from the paleeontologist which the importance of its study demands, although
im a stratigraphical point of view it is not inferior to the skeletons of any other class of the
Animal Kingdom. ‘The fact seems to have been almost entirely overlooked, that most of
the generic characters of the different groups of the Echinoidea are more indelibly impressed
on the separate pieces of their test than in the skeletons of any other class of the Invertebrata.

Unlike the shells of the Mollusca, the test of the Echinoidea constitutes an internal
and integral portion of the animal, being secreted by, and enclosed within, organized
membranes, and participating in the life of the organism; portions of the skeleton are
likewise intimately connected with the organs of digestion, respiration, and generation, as
well as with those of vision and locomotion.

As the analysis of the test of the Echinoidea, with full anatomical details of the struc-
ture of the skeleton in the Echinodermata in general, will be given in the Introduction to
this Monograph, it is unnecessary to enter at present minutely into the subject ; but, as
many of our readers are doubtless unacquainted with the terminology employed in the
description of the test of the Echinoidea, and the characters on which a diagnosis of the
species is made, it is desirable now to preface our description of the species with brief
explanations of the same, in this part of the work, illustrating the terminology by a refe-
rence to the plates for accurate figures of the different parts of the test, and the magnified
details of its anatomical characters.

ECHINODERMATA. 9

Terminology, or descriptive analysis of the component elements of the test of the
Echinoidea.

The test of the Echinoidea is composed of the following parts :

a. Five ambulacral areas.

6. Five inter-ambulacral areas.

c. Ten poriferous zones.

d. An anal opening, and anal membrane and plates.

e. A mouth opening, and buccal membrane and plates.

jf. Five jaws when organs of mastication exist; some are edentulous.

g. Tubercles of various sizes, developed on the outer surface of the plates.

i. Spines of various forms and dimensions, which are jointed with the tubercles.

These are the parts essential to be known; but there are others of secondary import-
ance, which will be described hereafter in their proper place.

The Body of the Echinoidea is divisible into three parts :

Ist. The calcareous envelope or skeleton has a globular, circular, oval, pentagonal,
hemispherical, conoidal, or discoidal form; it is composed of a framework of pentagonal,
hexagonal, and polygonal calcareous plates. This testaceous box is called the test. It
is the form, the dest of Agassiz; the general form, the test of Desmoulins; Ja coguille
of d’Orbigny.

2d. The visceral cavity, which contains the organs of digestion, respiration, circulation,
and generation, is formed entirely by the calcareous skeleton.

3d. The external surface of the test is covered with spines, which are moveably articu-
lated with the tubercles developed on the surface.

The normal position of the body.—In describing the different parts of the test of the
Echinoidea, it is assumed that the urchin, the common purple-heart urchin, Spatangus
purpureus, Miller, for example, is placed before the observer ; or, the common chalk urchin,
Micraster cor-anguinum, Klein, will answer equally well. The side with the single ambula-
crum lodged in the sulcus, and the mouth in that third of the base, is the axterior region.
The four other ambulacra are disposed in pairs, and correspond to the right and left sides
of the observer’s body; there is, therefore, a right antero-lateral and a right postero-
lateral; a left antero-lateral and left postero-lateral ambulacral area. The side having the
single inter-ambulacrum in the middle, and the anal opening in the upper part of the
border, is the posterior region. The four other inter-ambulacra are likewise disposed
in pairs, two of which, with the single ambulacrum, form the anterior part of the test ;
the other pair, with the pairs of ambulacra, forming the sides, and the single inter-

ambulacrum its posterior part.
2

10 TERMINOLOGY.

All the Echinoidea have the mouth situated at the under side of the body. The surface
in which this opening is placed is called the dase; that region of the test opposite to the
base is the wpper or dorsal surface.

The most convex part of the margin, border, or sides, between the base and the upper
surface, is called the circumference,—the ambitus of some authors. It is round, flat,
convex, angular, or carinated, according to the general form and thickness of the test.

The Jength, or antero-posterior diameter, is the distance between the anterior and
posterior regions, and corresponds to the middle line of the body.

The dreadth, or transverse diameter, is the distance between the greatest lateral con-
vexity of the circumference, in the direction of a line which will cut the line of length at
right angles.

The height is the distance between the most convex part of the upper surface and a
plane on which the base of the test can rest. ‘The apical disc is generally situated at the
vertex, but it is not always so. ‘The height has reference to the highest point of the test,
quite irrespective of any other consideration.

The ‘test has invariably two openings, the one for the mouth, the other for the anus.

The mouth-opening is always situated at the under surface; to its circumference is
attached the buccal membrane, and through its central aperture, when they exist,
protrude the five jaws. (PI. IV, fig. 1 6; Pl. XI, fig. 1.) The buccal, hke the anal mem-
brane in many families, is clothed with numerous small plates. In Cidaris, Rabdocidaris,
Goniocidaris, Diplocidaris, and probably in other Cidaride, the mouth-opening is central,
circular, or slightly pentagonal (PI. I, figs. 2a, 4a; Pl. II, figs. 1a, 26); but in Hemi-
cidaris, Diadema, Hemipedina, Pedina, Echinus, and other Kcuinip#, the mouth opening
is more or less decagonal, its margin being divided by notches (entaz/es) into ten lobes.
(Pl. III, figs. 26,66; PI. IV, fig.26,e; Pl. V, fig. le; Pl. VI, figs.2 6, 5¢.) The lobes
are, in general, unequal in size; those which correspond to the base of the ambulacra
are the largest, and are called the ambulacral lobes ; those corresponding to the base of the
inter-ambulacra are the inter-ambulacral lobes. The margin of the mouth-opening is called
the peristome ; to it the buccal membrane, which closes the base of the test, is attached.

The mouth-opening is central, and is armed with jaws, in the Crparipa, Ecurinipa,
SALENIDA, GALERITIDA, and CLypPrasTERIDa&. It is more or less excentral and edentu-
lous in the Ecutnonipa, Coniyritipz, Ecoinotampipm®, Hcuinocoryps#, and Sparan-
cip®. In these families it is round, oval, or pentagonal; sometimes its margin is ray-
like, or surrounded by five prominent lobes; in others it is distinctly bilabiate.

The anal opening is always in the upper surface, directly opposite to the mouth,
in the centre of the genital and ocular plates, and is either central or sub-central in the
Ciparips, Ecuinipx, and Satenipa. (PI. LI, figs. le, 8c; Pl. IV, figs. 1g, 27.) In
the other families its position varies much; sometimes it opens on the upper surface, as in
some GaLEritip® and Casstpuipm; sometimes it opens near the margin, or is supra-
marginal, marginal, or infra-marginal ; often it opens at the base, between the mouth and

ECHINODERMATA. 11

the border. During the life of the animal this opening was closed by an anal membrane,
and a series of small angular anal plates, the number and disposition of which vary in
the different genera. The anal plates are seldom preserved in fossil species; and the term
anal opening is given to all that part of the test occupied by them, the anal membrane,
and the vent.

The Ambulacral and Inter-ambulacral Areas.

The test is composed—lst, of twenty columns of calcareous plates of different sizes,
the plaquettes, Tifelchen, Assule, of authors. They are pentagonal in form, and are united
by harmonial sutures to form rays, which proceed from the mouth, where they have their
greatest breadth, to the apical disc, where they are narrowest. 2d, of a series of hexagonal
or polygonal plates, forming a disc, which occupies the upper surface of the test. 3d, of
ten rows of small plates, which are notched on their margins, to form holes: these consti-
tute the poriferous zones. 4th, of moveable spines, which are jointed with eminences on
the outer surface of the columnar plates.

The anbulacral plates form two narrow columns, which are bounded by two poriferous
zones. The space thus circumscribed is the ambulacral area. ‘There are five of these areas
in the test of the Echinoidea; in the Ciparip# the ambulacral areas are very narrow,
and support only granules (Pl. II, fig. 1a, 6); but in the Honin1pm@ (PI. VIII, fig. 1)
they are much wider, and have large tubercles on their surface. The comparative width of
the ambulacra, as compared with the inter-ambulacra, has led some authors* to divide the
family Cidaridee, including there the Hchinide, into two tribes,—the ANGusTISTELLA,
or Cidaridz with narrow ambulacra, and the LatistEnua, or Cidaride with broad
ambulacra. These two tribes nearly represent our two families: the Ciparip# are equal
to the ANGusTIsTELL&, and the Ecnin1p# are nearly equal to the LatisTELLa.

Pl. I, figs. 16, 2¢, 3c, 4c; Pl. II, figs. 1c, 2.g represent the structure of the ambu-
lacra in the Cidaride ; and Pl. V1, fig. 2d, and Pl. VII, figs. 3 and 4, show the structure
of the ambulacral areas in some Zechinide.

One of the ambulacral areas is single, and always represents the anterior region of
the test. In the spheroidal Achinide and Salenide, this is detected by its relation to the
apical disc, as the right antero-lateral genital plate always carries the madreporiform body ;
but in the oval, pentagonal, and elongated forms, its position and relation to the mouth
render it unmistakeable. The four other ambulacra are disposed in pairs.

The ¢nxter-ambulacral plates form two broad columns, which compose the inter-ambu-
lacral areas. Of these there are five, which alternate with the ambulacral areas in the
architecture of the test: the poriferous zones form the line of demarcation between these

* Albin Gras, ‘Description des Oursins Fossiles de département de l’Isére,’ p. 20.
E. Desor, ‘Synopsis des Echinides Fossiles,’ p. 1.

12 TERMINOLOGY.

two classes of columnar plates. The inter-ambulacral plates are all pentagonal, and
many times larger than the ambulacral; they carry on their external surface the large
primary tubercles. Of the five inter-ambulacral areas, one is single and posterior; and in
all the Echinoidea which have the anal opening external to the apical disc, it is in this
single inter-ambulacrum that the vent terminates. The other four inter-ambulacra are dis-
posed in pairs, and form the greater part of the anterior and lateral parts of the test.
They are called anterior pairs and posterior pairs respectively, to distinguish them from
the odd area, which is called the sizgle inter-ambulacrum.

Pl. I, figs. 16, 4e; Pl. Il, fig. 1 @,6,c, show the form and structure of the inter-
ambulacra in the Cidaride ; and Pl. VI, fig. 2,4; Pl. VIL, fig. 1 a, 6, the structure of
these areas in the Lehinide.

In the Cidaride, and in some Lchinide, the inter-ambulacral areas have only two
rows of primary tubercles; but in most of the Hchinide there are four, six, eight, or even
ten rows of primary tubercles in these areas.

The Poriferous Zones.

The poriferous zones are situated on each side of the ambulacral areas. (Pl. I, fig. 4a ;

Pl. Il, figs. 1 a, 4, 2 4, ec.) They are composed of a very great number of small pieces,
articulated together in such a manner as to form a series of holes, the corresponding edges
of the plates, remaining uncalcified at certain definite intervals, to produce foramina, which
are destined for the passage of retractile tubular suckers. The form and structure of the
poriferous zones afford a good generic character. As there are two poriferous zones
bordering each ambulacral area, it follows that there are ten zones. Some authors give the
collective name ambulacra to the zones and the area, but, for obvious reasons, we consider
them distinct sections of the test, and treat of them as such. The pores are round, oblong,
or elongated ; the pores forming a pair may be egual or unequal, or, in relation to each
other, they may be ¢ransverse or oblique ; they may be contiguous or remote, and when they
are united by a transverse sulcus, they are said to be conjugate.
_ The pores are differently arranged in the zones in the different families. “ When they
are disposed in single pairs they are said to be wnigeminal (PI. II, fig. 1c); when in
double pairs they are dcgeminal (Pl. VI, fig. 3c, 7); when in triple oblique pairs they are
trigeminal (Pl. VI, fig. 2g; Pl. XII; Pl. XIV; Pl. XV), or when they are grouped in a
greater number, as in many living species of the genus Hehinus, they are polygeminal.

When the zones extend in a straight uninterrupted line from the mouth to the apical
disc, they are said to be s¢mple, as in the Cidaride, Echinide, Salenide, Galeritide,
Echinonde ; when the zones, after parting from the apical disc, expand, and again con-
tract, thereby forming a leaf-like figure on the upper surface of the test, they are said to
be petaloidal, as in the Clypeasteride; when the petal is not so complete as in the
Cassidulide, it 1s sub-petaloidal. 'The zones are complete when they extend without inter-

ECHINODERMATA. 13

ruption from the mouth to the disc ; they are in/errupted when they terminate on the upper
surface, and reappear again at the base near the mouth; they are /imited when they form
only a star on the dorsal surface. These terms all represent generic and specific characters
of greater or less value, which require to be carefully noted in the description of the species.

The Apical or Genital Disc.

The apical disc occupies in general the centre of the summit of the test, and is composed, in
most of the genera, of ten plates,—namely, five genital plates, and five ocular plates. (Pl. I,
figs. 1 e, 27, and Pl. IV, fig. 27) In the Selenide there is one or more additional plates
introduced. The five genital or oviductal plates correspond to the summits of the inter-
ambulacral areas (PI. III, figs. 1 a, 3a); two plates form an antero-lateral pair, two a
postero-lateral pair, and the single plate is placed behind. On the right antero-lateral
genital plate (Pl. IV, figs. 1g, 2) is placed a spongy prominent mass, called the
madreporiform body. ‘The plate, supporting this body, was supposed by Agassiz and
Desor always to represent the posterior part of the test, but we shall show in the sequel
it is invariably placed on the right antero-lateral plate.

The ocular plates are placed at the summit of the ambulacral areas. They are small
heart-shaped bodies (Pl. IV, fig. 1g), and are wedged into the angles of the genital plates
around the circumference of the disc.

The swr-anal plates are found only in the Salenide. They consist of one or many
elements placed in the centre of the genital circle, and almost always before the anal
opening. (Pl. XVI.)

The anal plates are very small bodies, and are variable as to size and number ; they
clothe the membrane of the anal opening, and are well seen in recent urchins, but are
seldom preserved in fossil species.

The Tubercles.

The plates which compose the test of the Cidaride, Echinide, and Salenide, have large
tubercles developed on thei external surface. They are divided into primary tubercles,
semi-tubercles, secondary tubercles, minute tubercles, granules, and miliary granulation. In
the other families the tubercles are smaller, more numerous, and less complicated.

The primary tubercles form two rows in the inter-ambulacral areas of the Cidaride
(Pls. I and II), and in the genus Hemicidaris (Pls. III and IV), and a section of the genus
Diadema (Pls. VI and VII); and four, six, eight, or ten rows in many Aehinide.

The semz-tubercles are found at the base of the ambulacral areas of the genus Hemz-
etdaris. (Pl. III, fig. 1 4, ¢; Pl. IV, fig. 1 ¢, d.) In a section of the genus Hemipedina,
they likewise are found at the base of the ambulacra (PI. XJ, fig. 2).

14 TERMINOLOGY.

The secondary tubercles are found in many of the Hchinide, ranged in general on the
ambulacral side in the primary tubercles. They are found likewise on the centro-sutural
side of the primary rows (Pl. VII, fig. 4, and Pl. VIII, fig. 1) of many Diadema, Pedina,
fTemipedina, and Lchinus.

The minute tubercles ave the small tubercles which are found on the margins of the
ambulacral areas in the genera Cidaris and Hemicidaris. (Pl. IL, fig. 1 6, c; Pl. IV, fig. 1 d.)
They sometimes fill up spaces at the base of the inter-ambulacral areas, as in some Diademas ;
(Pl. VI, fig. 2.7) they are always raised on little eminences, and are in general perforated
like the secondary and primary tubercles. In this respect they are distinguished from the
granules.

The granules are small, round, hemispherical elevations, scattered more or less regularly,
and distributed over different parts of the plates of the test. In some species of the genus
Cidaris, they are arranged in rows in the centre of the ambulacral areas (PI. 1, fig. 4e;
Pl. II, figs. 1 c, 2g; Pl. III, fig. 2 d); or they form circles around the circumference of
the areolas of the primary tubercles. (PI. II, fig. 2.)

The miliary granulation is formed by a number of small granules closely set toge-
ther in the centre of the ambulacra (Pl. III, fig. 6a: Pl. V, fig. 2d), or on the inter-
tubercular surface of the large plates forming the inter-ambulacra. (Pl. I, fig. 6,¢; Pl. VI,
fig. 2 c, a.)

The primary tubercles of the genera Cidaris, Hemicidaris, Diadema, Hemipedina,
Pedina, &c., consist of the following parts:

The hemispherical tubercle or mamelon, which 1s sometimes perforated in the centre,
as in all the Cidaride (PI. II, fig. 1 c, d): sometimes it is imperforate, as in many
Echinide (Pl. XVI).

The doss or mamillary eminence is the conical prominence which rises from the surface
of the tubercular plate (PI. II, fig. 1 d); its summit supports the tubercle; its margin is
sometimes crenulated in Cidaris, Hemicidaris, and Diadema, and sometimes smooth in
Hemipedina and Pedina. These characters are important for generic distinctions.

The areola or scrobicule (PI. II, fig. 1c) is the round, oval, or elliptical, smooth,
excavated space which surrounds the base of the boss. ‘This space is sometimes wide
(Pl. I, fig. 1 c), sometimes narrow (PI. IV, fig. 1 d) ; sometimes its margin is elevated into
a ridge which encircles it completely (Pl. II, fig. 2g); the scrodicular or areolar circle
is then said to be complete; sometimes the upper and under sides of the circle are want-
ing, when it is zwcomplete, and the areolas in this case are said to be confluent. (PI. I,
ine, US TRAY sinbsysio lh ai, 4225)

The row of granules, which encircles the areola, is called the areolar or scrobicular
circle.

The miliary zone is the space comprised between the two ranges of primary tubercles.
This zone is sometimes destitute of miliary granules, when it is said to be naked; some-
times it is covered with a close-set granulation. We have, therefore, the ambulacral miliary

ECHINODERMATA. 15

zone, and the inter-ambulacral miliary zone, when they occupy these different regions of
the shell.

When the granules are microscopic, and are closely clustered together to form certain
narrow, circumscribed bands or fascioles which intersect the general tubercular surface,
and occupy fixed positions on the test, the microscopic granules composing these zones
are called fasciolar.

Fascioles are only found in two families, in one genus of the Hehinocoryde, and
im almost all the genera of the Spatangide. The form, width, structure, and position of
these bands must be carefully noted, as they afford important characters, both positive and
negative, which serve in the diagnosis of the genera.

When the fasciole surrounds the circumference of all the petaloidal portions of the
ambulacral areas, it is called per¢petalous ; when it encircles the single ambulacrum alone,
it is internal ; when it extends along the flanks, it is /ateral; when it passes in whole or
in part along the circumference, it is marginal: and when it surrounds the base of the
single iter-ambulacrum, it is sv6-ana/: sometimes there is only ove, sometimes there are
two or three, of these fascioles in different genera.

Hach family has a special arrangement of the tubercles, granules, and fascioles, which
will require a detailed notice in the general outline of the structural characters prefixed to
the description of each natural group.

The sutural impressions are the lines along which the plates are united together.
Sometimes they are mere lines (Pl. I, fig. 46; Pl. II, figs. 1 4, 2c); sometimes the im-
pressions amount to excavations out of the borders of the plates, and give rise to cavities
therein, as in the genus Zemnopleurus.

The angular or sutural pores are small impressions, situated in some genera at the
angles of the plates, upon the median line of the miliary zones.

The external appendages of the Test.

The spines, or Radiolii as they were called by Plott, Langius, and other old authors,
are the calcareous appendages which are moveably articulated with the tubercles of the
test. ‘They present numerous modifications as to size, form, and sculpture, which are all
intimately connected with specific characters. Some are short, elongated, flattened, cylin-
drical, fusiform, or subulate ; others are compressed, spatuliform, or triangular; others, on
the contrary, are expanded, pyriform, or claviform. The surface of the spies is smooth, or
striated with fine or coarse longitudinal lines; some have verticellate processes at regular
intervals; others have asperities, prickles, or granules, disposed with more or less regu-
larity over the surface; the different parts of the spine have received the following

names :
The articular cavity, or acetabulum, is the socket by which the spine articulates with

16 TERMINOLOGY.

the tubercle. Its margin is smooth, or crenulated, according as the summit of the boss is
smooth or crenulated. (PI. II, fig. 2e¢.) In all the genera in which the tubercles are per-
forated, there is a corresponding pit in the socket of the spine for the attachment of a
round ligament, which passes from the tubercle to the spine.

The head is that part of the spme which contains the articulating cavity, and is united
to the stem near the neck. (Pl. I, fig. 1 f; Pl. Il, fig. 2.)

The med ring surrounds the head, It is a prominent ridge, more or less deeply
crenulated, around which the muscular fibres that move the spine are firmly attached.
(Pl. I, fig. 5 6.)

The xeck of the spine is the smooth space between the line of junction above the milled
ring and the rugose body of the spine. (PI. I, fig. 1) It is often finely striated with
longitudinal lines. In long slender, tapering spines, (Pl. IV, fig. 1 0,) the neck often
cannot be distinguished from the body, into which it passes.

The stem, or body of the spine, is the part which exhibits the greatest variety of forms.
Smooth and muricated varieties are figured in Plates I, I, IV.

The organs of mastication, forming the lantern of Aristotle, are rarely preserved in fossil
species. They consist of five jaws, each carrying a long tooth. (Pl. IV, fig. 16,7) As
these parts form a complicated mechanism, their analyses and description will be given at
length in the anatomical part of the Introduction.

In this descriptive terminology of the skeleton, we have limited our observations to the
Ecarnorpna, the iconography and description of the British Oolitic species of which forms
the first part of this Monograph: it is our intention to preface the description of the
ASTEROIDEA, OpHtuRoIDEA, and Crinoipna, which follow seriatim, with similar analyses
of the specialities of their organization.

On the relative value of the external organs in the classification of the Hchinoidea.

The mouth is always basal, central, subcentral, or excentral, but the excentricity is
invariably towards the anterior border. This opening does not, therefore, afford a charac-
ter of primary importance, although, in connection with others, it is valuable in the definition
of families. ‘The mouth is sometimes armed with jaws, but sometimes it is edentulous.

The position of the anal opening affords a character of primary importance. In one great
section the anus opens within the centre of the apical disc, surrounded by the genital and
ocular plates. The relation, therefore, of the digestive organs to those of generation and
vision, is an important primary character for the zoologist. In another section the anal
opening is without the apical disc, and is more or less external to, and at a greater or less
distance from, the genital and ocular plates. The physiological importance of the external

ECHINODERMATA. Va

relation of the organs of digestion, generation, and vision, to each other, imparts great
value to the position of the anal opening ; and hence it forms the basis of the subdivision
of this order into two sections, which are thus defined :

Echinoidea endocyclica.

A. Test circular, spheroidal, more or less depressed, rarely oblong ; mouth in the centre
of the base. Anus in the centre of the upper surface, directly opposite to the
mouth, surrounded by the five perforated genital plates, and having external to
them the five ocular plates. Mouth always armed with five powerful calcareous
jaws, formed of many elements, disposed in a vertical direction.

Eichinoidea exocyclica.

B. Test sometimes circular and hemispherical ; oftener oblong, pentagonal, depressed,
clypeiform or discoidal; mouth central or ex-central. Anus external to the circle
of genital and ocular plates, never opposite the mouth, but situated in different
positions in relation to that opening: four of the genital plates are generally
perforated. The mouth is sometimes armed with five jaws, but it is oftener

edentulous. The elements of the lantern are disposed in a more or less horizontal
direction.

The structure of the ambulacral areas, and the poriferous zones, which are in relation
with the organs of respiration and locomotion, afford good characters of secondary im-
portance, for grouping the genera into natural families, especially when taken in connection
with the position of the anal opening, which varies in its relation to that of the mouth
opening in different families.

The form, number, and arrangement of the tubercles, and the spines which are jointed
with them; the miliary granulation; the bands of microscopic granules forming the fas-
cioles, which have determinate and permanent positions on the test ; added to the size and
number of the elements of the apical disc, and the position of the anus, afford collectively
good characters for defining the genera.

‘The minute details in the structure of the plates; the form, and size, and number of
the tubercles on each of them,—the form and arrangement of the pores in the zones; their
proximity or remoteness from each other; the general outline of the test, which has only
certain limits of variation ; the character of the sculpture on the plates; the form of the
areolas; the presence or absence, the size and distribution of the granules forming the areolar
or scrobicular circle; the completeness or incompleteness of the same. The length of the
spines, their form and sculpture, are all pomts which afford good specific characters, as
they are persistent details which are developed on every considerable fragment of the test
and spines of Hchinoidea.

3

18 NATURAL FAMILIES.

Taking these general principles for our guidance, we subdivide the Hchinoidea into
the following natural families :

Cidaride.
Echinoidea endocyclica. Hemicidaride.
Anus within the genital plates, Diademade.
always opposite the mouth. | Echinide.
Salenidee.
Echinoconide.
Order—ECHINOIDEA. Collyritide.
Echinoidea exocyclica. Echinonide.
Anus without the genital plates, Signing seca.
: Echinolampide.
never opposite the mouth.
Clypeasteride.
Echinocoride.
Spatangidee.

Family \. Crparip#.—Test thick, spheroidal ; inter-ambulacral areas very wide ; pri-
mary tubercles large, perforated ; bosses crenulated or uncrenulated, spines large, thick,
and mostly claviform; ambulacral areas very narrow; poriferous zones narrow, pores
unigeminal, rarely bigeminal ; mouth opening large, inferior, central, circular or penta-
gonal; peristome destitute of notches, always armed with large and powerful jaws. Anal
opening wide, superior, opposite to the mouth, surrounded by five genital plates, perforated
for the genital canals, and five ocular plates excavated for lodging the eyes; buccal and
anal membranes covered with scales.

Types. Cidaris florigemma, Phillips. Crdaris Smithii, Wright. (PI. IL.)

Family 2. Humiciparip#.—Test thick, spheroidal, or more or less depressed ; ambu-
lacral areas narrow or wide, with semi-tubercles at their base only, or extended throughout
the area; inter-ambulacral areas with two rows of primary tubercles, rarely more than
eight in each row ; the tubercles of both areas are perforated, and the bosses are deeply
crenulated; the poriferous zones are narrow and undulated; the pores are unigeminal
throughout, except near the peristome, where they are bigeminal and trigeminal. The
mouth opening is large; the peristome is decagonal, and is divided by more or less deep
notches into ten lobes; the jaws are large and powerful; the apical disc opposite the
mouth is small, and is composed of five genital plates and five ocular plates. The spines
are long, thick, cylindrical, tapering, or claviform, or stout, compressed, and angular ;
their surface is smooth, or covered with fine longitudinal lines, but, as far as is known,
neither prickles nor asperities are developed thereon.

Types. Lemicidaris intermedia, Fleming (Pl. IV). Acrocidaris formosa, Agassiz.

Family 3. Dispemapda.—Test thin, circular, or pentagonal, more or less depressed ;

ECHINODERMATA. 19

ambulacral areas wide, with two or four rows of primary tubercles ; inter-ambulacral areas
with two, four, six, or more rows of tubercles, nearly of the same size and structure as
those of the ambulacra; the tubercles are perforated or imperforated, crenulated or
uncrenulated, in different genera ; the apical disc opposite the mouth is small, and com-
posed of five genital and five ocular plates ; the poriferous zones are narrow; the pores
are unigeminal or bigeminal. ‘The mouth opening is large and decagonal; the peristome
is divided into ten lobes by deep notches; the spines are long, cylindrical, more or less
slender, and are either tubular or solid ; sometimes they are encircled by spiral verticillate
processes, or their surface is sculptured with fine longitudinal lines.

Types. Astropyga radiata, Leske. Diadema pseudo-diadema, Lamarck (P]. VII,
fig. 1). Cyphosoma Kénigit, Mantell. Hemipedina Marchamensis, Wright (P). XI, fig. 1).

Family 4. EKourxtp#.—Test thin, spheroidal; inter-ambulacral areas, with primary
tubercles, small and of various sizes, perforate or imperforate ; bosses crenulate or un-
crenulate; ambulacral areas wide, always supporting two or more rows of primary
tubercles ; poriferous zones narrow or wide, pores unigeminal, trigeminal, or polygeminal,
and disposed in arcs; spines short, mostly subulate. Mouth opening large, inferior,
always decagonal; the peristome divided into lobes by notches more or less deep.
Anal opening small, superior, opposite the mouth, surrounded by five genital and five
ocular plates ; buccal membrane naked.

Types. Arbacia Forbesii, Wright (Pl. XIT). Glypticus hieroglyphicus, Minster
(Pl. XII). Hehinus bigranularis, Lamarck (Pl. XIV).

Family 5. Satmxip#.—Test thin, spheroidal ; inter-ambulacral areas wide, with few
primary tubercles, which are either perforate or imperforate, crenulate or uncrenulate ;
ambulacral areas narrow, carrying secondary tubercles. Mouth opening small or large,
inferior, decagonal ; peristome more or less notched. Anal opening superior, surrounded
by the plates of a large apical disc, composed of more than ten pieces, and which occupies
a wide aperture in the superior part of the test. Poriferous zones narrow, pores unige-
minal, except near the peristome, where they are trigeminal. Spines long, subulate,
circular, or flattened. Species all extinct; the genera distributed in the Oolitic, Cretaceous,
and Tertiary rocks.

Types. Salenia petalifera, Defrance. Acrosalenia hemicidaroides, Wright (Pl. XVI).
Goniophorus lunulatus, Agassiz.

Family 6. Ecutnocon1ip#.—tTest thin, circular, elongated or pentagonal, elevated or
depressed ; inter-ambulacral areas wide, ambulacral areas narrow; the external surface of
the plates of both covered with numerous small, perforated, and crenulated tubercles ;
poriferous zones narrow, pores unigeminal, except near the base, where they are tri-
geminal. Mouth opening inferior, central, circular, or pentagonal, armed with five jaws ;

20 NATURAL FAMILIES.

peristome notched, dividing the circumference into ten nearly equal lobes. Apical disc
central, superior, composed of five genital and five ocular plates ; the madreporiform body
being large, and extending from the right antero-lateral genital plate ito the centre of
the disc. Anal opening situated at the upper surface, in the margin, or at the inferior
surface of the test. Spines small, short, subulate. The species are all extinct; the genera
are distributed in the Oolitic and Cretaceous rocks.

Types. Hchinoconus albo-galerus, Klein. Pygaster semi-sulcatus, Phillips (Pl. XVII).
Holectypus depressus, Leske.

Family 7. Coutyritip#.—Test thin, circular, or oval; ambulacral areas meeting at two
points on the upper surface, which are more or less apart; poriferous zones narrow, pores
unigeminal; tubercles small, numerous, perforated, and crenulated. Mouth opening ex-
central, small, round, oval ; peristome feebly fissured; jaws unknown. Anus round, oval,
supra-marginal; elements of the apical disc detached; four genital holes. The species
are all extinct, and distributed in the Oolitic and Cretaceous rocks.

Types. Collyrites ringens, Desmoulins. Collyrites ovalis, Parkinson.

Family 8. Koutnonip#z.—Test thin, oval; poriferous zones narrow, meeting at the
apical disc; pores unigeminal; tubercles of both areas nearly equal, but neither perforated
nor crenulated ; spines stout, subulate. Mouth opening nearly central, irregularly penta-
gonal, and edentulous. Anal opening oblong or pyriform, basal or marginal, closed by
anal plates ; apical disc nearly central ; four genital pores. One group is living in tropical
seas; another is found fossil in the Cretaceous rocks.

Types. Lchinoneus cyclostomus, Leske. Pyrina Desmoulinsii, D’ Archiac.

Family 9. Koutnosrissip#.—Test thin, circular, oblong, sub-pentagonal or clypeiform,
covered with small tubercles, surrounded by excavated areolas; ambulacra narrow,
enclosed by poriferous zones, more or less petaloidal ; pores set at different distances apart,
and united by connecting sutures. Mouth opening small, nearly central, pentagonal,
and edentulous, in general surrounded by five lobes. Anal opening, lodged in a sulcus, m
the upper surface of the single inter-ambulacrum, or in a marginal depression thereof ;
apical disc small, four genital lobes; madreporiform body extending into the centre of the
disc. One species is living, the others are all extinct, and distributed in the Oolitic,
Cretaceous, and Tertiary rocks.

Types. Lchinobrissus clunicularis, LIhwyd. Clypeus sinuatus, Leske. Catopyus
carinatus, Goldfuss. Pygaulus cylindricus, Desor.

Family 10. Kournouamprpa.—Test thin, oblong, oval, elevated or sub-discoidal ;
ambulacra large, petaloid; poriferous zones wide; pores placed apart, and united by a
suture ; the zones extend near to the margin. Mouth small, surrounded by five lobes,

ECHINODERMATA. 21

sometimes it is transversely oblong. Anal opening transversely oblong, and infra-marginal ;
apical disc small, excentral, with four genital holes. Some species are living in warm
seas, but the greatest number are extinct, and distributed in the Oolitic, Cretaceous,
and Tertiary rocks.

Types. Lchinolampas orientalis, Gray. Pygurus depressus, Agassiz. Conoclypus
Leskii, Goldfuss.

Family 11. Cuypnaster1p#.—Test thick, elevated or depressed, circular, elliptical, or
pentagonal; the surface closely covered with small, nearly equal-sized tubercles, sunk in
the plates, and surrounded by ring-like areolas, the tubercles carrying short hair-like spines.
The mouth large, central and pentagonal, and armed with five strong jaws, which carry the
same number of teeth. The anus posterior, marginal or infra-marginal; the interior of
the test is sometimes divided by pillar-like processes formed of the inner layer of the plates.
The dorsal portions of the ambulacral areas have a petaloid form, circumscribed by large
poriferous zones ; the basal portions are narrow, rectilineal, or branched ; the five genital
plates form a circle around the madreporiform body, and between these are wedged the
five ocular plates. This family includes the genera Clypeaster, Lamk., Laganum, Klein.,
Echinarachnius, Van Phels., Arachnoides, Klein., Scutella, Lamk., Dendraster, Agass.,
Lobophora, Agass., Encope, Agass., Echinodiscus, Breynius, Mellita, Klei., Runa, Agass.,
Moulinsia, Agass., Scutellina, Agass., Echinocyamus, Van Phels., Fidularia, Lamk.,
Lenita, Desor.

Types. Clypeaster rosaceus, Lamarck. Scutella subrotunda, Lamarck. Echinarachnius
placenta, Gmelin.

Family 12. Houtnocoripa.— Test thick, oval and elevated, sometimes cordate ;
ambulacral areas narrow ; poriferous zones narrow, pores unigeminal; test covered with
small tubercles, which are perforated and crenulated. One genus has a marginal fasciole.
Mouth opening small, excentral, transversely oblong. Anal opening nearly of the same
size, oblong, marginal, or supra-marginal. Apical disc elongated, nearly central, with four
genital pores; the cordate forms have an anterior central depression. The species are
all extinct, and are limited to the Cretaceous rocks. .

Types. Hchinocorys vulgaris, Breynius. Holaster sub-globosus, Leske. Cardiaster
granulosus, Goldfuss.

Family 13. Spatancip#.—Test thin, oval, oblong or cordiform, and satisfactorily ex-
hibiting the bilateral symmetry of the Hehznoidea. The anal opening is posterior and supra-
marginal, and is closed by a complicated series of small plates. The apices of the ambu-
lacral areas are united at the summit of the test. The anterior smgle ambulacrum has a
different structure from the antero- and postero-lateral pairs, and is in general lodged in a
depression of the test, which extends to the anterior border, forming the anteal sulcus ; the

22 NATURAL FAMILIES.

test is extremely thin, and is covered with small tubercles, which support hair-like spines.
Besides these, there are some larger crenulated and perforated tubercles, which support
large spines. ‘There are two or four genital pores, which are sometimes placed close
together, but are in other genera apart. The eye-plates are five in number, and are placed
at the apices of the ambulacra, in a pentagonal form, around the genital plates. On the
surface of the test of some Spatangide certain delicate lines called fascioles are observed,
having a smoother appearance than the tubercular surface of the test: they are furrows,
strewed with microscopic tubercles, and destined to carry very delicate spines, which,
when seen under the microscope, appear to have the same structure as the Pedicellarie.
The fascioles have a different disposition in each genus, and afford a good character in
making definitions of the same. When the fasciole surrounds the ambulacral petals like an
undulating groove, as in Hemeaster, Schizaster, &c., it is said to be pert-petalous ; when it
surrounds the single ambulacrum, as in Amphidetus, it is internal ; when it extends along
the sides, as in Schizaster, it is lateral; when it surrounds the circumference of the test,
as in Pericosmus, it is marginal ; when it is limited to the base of the anal opening, it is
sub-anal. Sometimes, in the same genus, more fascioles than one exist; thus the sub-
anal and peri-petal are frequently associated together.

Types. Spatangus purpureus, Miller. Brissus lyrifer, Forbes. Brissopsis Duciei2,
Wright.

ECHINODERMATA. 23

Family 1—Ciparip#.

Test thick, turban-shaped, more or less depressed at the oral and anal apertures.
Mouth opening wide, central; peristome circular or pentagonal, but without notches ;
aperture closed by a buccal membrane, covered with small spines, metamorphosed into
imbricated scales, upon which the pores from the zones are prolonged.

Opening for the apical disc very large; the disc composed of five large equal-sized
angular genital plates, and five ocular plates; anus opens in the centre of the disc, directly
opposite to the mouth ; anal membrane clothed with small angular plates, unequal in size,
and variable in number.

Ambulacral areas extremely narrow, composed of a great number of very small plates,
which have only minute tubercles, or rows of small granules on their surface, but never
supporting tubercles carrying primary spines.

Inter-ambulacral areas very wide, composed of large plates, rarely more than from six
to eight in one column; the external surface of each plate carries a large perforated
tubercle, raised on a prominent boss, and encircled by an areola, which has either a
round or oval form; the areola is surrounded in general by an elevated margin, on which
are placed a circle of granules, the scrobicular circle, usually larger than those filling the
miliary zone.

The poriferous zones are narrow, and extend without interruption from the margin of
the buccal membrane to the apical disc; the pores in general are strictly unigeminal, but
in one genus they are bigeminal; the pores are contiguous, or separated by septa more
or less thick.

The jaws, five in number, form a very powerful lantern, which is moveably connected
with, and supported by, a series of calcareous processes or auricles, arising from the
inner surface of the test; the teeth are more simple, and the lantern. less complicated,
however, than in the Hchinide.

The spines in this family are large, strong, cylindrical, fusiform, prismatic, club-shaped,
or flattened; their surface is sometimes covered with longitudinal lines, or with prickles
or granules, which in general have a linear arrangement, or they are more or less irregu-
larly disposed ; but the form and sculpture of the spine has invariably, as far as is known,
a specific value, its dominant characters being always persistent.”

* The form and general character of the spine should, in every case, be examined with scrupulous
attention, and, whenever in fossil species the spines are found attached to their test, the facts connected
therewith should be noted with the greatest accuracy. The neglect of this caution has been the cause of
much confusion, and led to some serious errors, as will appear in the sequel,

24 CIDARIDAL.

The Cidaride are the most ancient type of the Echinoidea. The remains of different
forms of this family are found in the Silurian, Devonian, and Carboniferous rocks, as well as
in those of the Secondary and Tertiary periods. In his valuable Synopsis, M. Desor describes
six genera in this tribe: these are Cidaris, Klein.; Rabdocidaris, Desor; Diplocidaris,
Desor; Porocidaris, Desor; Goniocidaris, Desor ; Palgocidaris, Desor. Of this number
three are extinct— Dzplocidaris, Porocidaris, and Paleocidaris ; two contain both extinct
and living forms—Cidaris and Rabdocidaris ; and one is only found living—Goniocidaris.

ECHINODERMATA. 25

Genus—CIDARIS, Klein. 1734.

Ecuinus, Linneus, Hissenger, &e.

Ecuinites or Histrix, Bourguet.

Ciparis, Klein, Leske, Defrance, Blainville, Agassiz, Desor.
CiparitEs, Lamarck, Goldfuss, Gray, Desmoulins.

General form circular or turban-shaped; test thick, sub-spheroidal, nearly equally
flattened on the under and upper surfaces,

Ambulacral areas very narrow and undulated, supporting only minute granuloid
tubercles, or small granules, disposed in two, four, or six close-set rows.

Inter-ambulacral areas at least four times the width of the ambulacral, furnished with
two rows of large primary tubercles, from four to six in a row,—rarely there are ten.

The tubercles are perforated; the bosses are large and prominent, and their summits
are smooth or crenulated; the areolas are wide, and in general are deeply excavated ;
they have a round or oval figure, and their elevated margin is in general surrounded by a
complete circle of granules (the scrobicular circle).

The miliary zones are concave, and more or less wide in proportion to the size of the
primary tubercles ; they are filled with numerous rows of small, close-set granules.

The poriferous zones are narrow ; the pores are unigeminal and contiguous; they are
separated by septa more or less thick.

The spines are robust and massive, cylindrical, fusiform, or claviform ; their surface is
covered with longitudinal lines, or furnished with prickles, granules, or other asperities,
which often assume a linear arrangement.

The mouth opening is circular or pentagonal, without notches; the buccal membrane
is covered with imbricated scales, on which the pores from the zones are prolonged.

The apical disc is large, and is composed of pentagonal, nearly equal-sized, genital
plates, and triangular ocular plates.

The lantern is powerful, composed of massive pyramids, the branches of which are not
united at their summits; the teeth are canaliculated, and formed of a folded plait, without
a carina on the inner surface.

Notwithstanding the limitation of the genus Cidaris of Kleim., by Lamarck, Goldfuss,
' Agassiz, and Desor, it still forms an extensive group of Urchins, which range from the
Paleozoic rocks into our modern seas.

This genus divides itself into two types; im the one, the mammillary bosses have
smooth summits; in the other, they are more or less crenulated.

Tue First Typr.—TZubercles with smooth and uncrenulated bosses, exist in our present
seas, and are found fossil in the Carboniferous, Triassic, Cretaceous, and Tertiary rocks.
i 4

26 CIDARIS.

Tur second trPE.—Twdercles with the summits of the bosses more or less crenulated,
are found in the Triassic and Oolitic rocks.

There are some exceptions to these rules, for Cidaris marginata, Goldfuss, and
Cidaris levigata, Desor, both from the Coral Crag, have smooth bosses; and some
species from the Neocomian and Cretaceous strata are said to have the summits of
these eminences crenulated.

A. Cidaris from the Inas.

Crparis Epwarpsu, Wright. PI. I, fig. 1 a, 6, ¢, d, e, f-

Crparts Epwarpsil, Wright. Annals and Magazine of Natural History, 2d series, vol. xiii,
p- 161, pl. 11, fig. 1 a—f.

Test crushed; the true form therefore unknown. Ambulacral areas narrow, gently
flexed, and furnished with two rows of small perforated marginal tubercles, and a median
row of smaller tubercles irregularly interspersed amongst them; the marginal tubercles
being alternately larger and smaller ; poriferous zones wide, with large, closely approximated,
oblong pores; inter-ambulacral areas about four times the width of the ambulacral, with
two rows of large primary tubercles, the areolas of which are confluent throughout ; miliary
zones wide, and covered with numerous small granules; primary spines long, showing a
complex structure ; secondary spines short, with blunt apices; the surface of both covered
with delicate longitudinal lines ; mouth armed with five powerful jaws, each having carinated
ridges on their convex surface ; upper part of the test unknown.

Description.—The great argillaceous deposits of the Oolitic group—the Lias, the
Oxford Clay, and the Kimmeridge Clay—were formed under conditions which appear to
have been unfavorable to the development of Urchin life; for, although these rocks have
been industriously explored, they have hitherto yielded very few remains belonging to the
Echinoidea: this remark does not apply only to the English Oolitic group, but is appli-
cable to the whole series as developed on the continent of Europe. Although a few forms
of Cidaride lived in the Silurian, Devonian, Carboniferous, Permian, and Triassic
seas, still it was in the Jurassic ocean that they existed in any considerable numbers ; and
this fact gives increased interest to the study of the anatomy of these Oolitic representatives
of this most beautiful family, one of the oldest of which we have figured in Pl. I, fig. L.
It is much to be regretted that the specimen before us is the only one of the species that
has been found in Gloucestershire in anything like a state of preservation, a few fragments
of its test having been rarely collected in two or three other localities. At Lyme Regis one

ECHINODERMATA. 27

specimen of this species, with some of its spines attached, has been discovered; and one
was found in the Lias of Yorkshire; but these are the only examples with which we are
acquainted. The specimen which forms the subject of our figure was discovered by
G. E. Gavey, Esq., C.E., whilst cutting through the shales of the middle Lias, to form the
Oxford, Worcester, and Wolverhampton Railway; the zone of Lias in which it was
found was that containing Ammonites maculatus, Young and Bird; it was associated
with three or four other remarkable species of Asteriade, Ophiuride, and Crinoide, in a
high state of preservation, and which will be figured and described in the future parts of this
Monograph. ‘The conditions under which these Echinoderms were found are curious and
deserve notice. Uraster Gaveyi, Forbes, was found lying on the upper surface of a slab of
sandstone, twelve inches thick, at twenty-five feet below the surface, associated with frag-
ments of Hvtracrinus, Ammonites, and other fossils. All the specimens of Tropidaster
pectinatus, Forbes, and Cidaris Hdwardsii, Wright, were found imbedded in the under
surface of a thick slab of ironstone, at twenty feet below the surface. Almost all the
specimens show the under surface uppermost, and most of them had their spines attached
to the spinigerous tubercles. Cedaris Edwardsii, when first discovered, was so entirely
covered with spines, that the inter-ambulacral plates were almost concealed. For further
details relating to this section, and the fossils found therein, the reader is referred to
Mr. Gavey’s paper.”

The specimen is crushed and flattened, and lies with its mouth and jaws uppermost.
At our request, Mr. Baily, in his beautiful drawing, has restored the urchin to its globular
form ; but it must be added, that all the parts of the test, and the details he has given of
its structure, are faithful copies of the original. The ambulacral areas are provided with
two rows of small perforated tubercles on the margin of the areas, each plate thereof
developing alternately a smaller and a larger marginal tubercle (PI. I, fig. 1 6); amongst
these a row of small granules are scattered somewhat irregularly throughout the areas.
All these tubercles supported short, stout, blunt-pointed spines (fig. 1d, e), the surface
of which is delicately sculptured with longitudinal lines: many of these spines are seen in
situ in the specimen, although many have been removed to expose the surface of the
test. ‘The poriferous zones are wide, and follow the gentle flexures of the ambulacral
areas; the pores are large and oblong, and the two pores forming a pair are separated
by very thin partition walls, a circumstance which forms a good diagnostic character
(Pl. I, fig. 1 4); there are five pairs of pores opposite each of the large tubercular plates.

The inter-ambulacral areas are four times the width of the ambulacral; they are com-
posed of rather narrow tubercular plates, which support two rows of primary tubercles, set,
therefore, rather closely together, in a vertical direction, so that the areolas are all confluent
above and below (PI. I, fig. 14); the miliary zone is wide, and filled with six rows of
minute, close-set, perforated tubercles, each of which is raised on an elevation of the test ;

* Quarterly Journal of the Geological Society,’ vol. ix, p. 29, with sections of the Railway Cuttings.

28 CIDARIS.

the semi-circlet surrounding the outer and inner margin of the areolas is composed
of granules very little larger than those which fill up the miliary zone. The primary
tubercles are of moderate size; the number in each column is uncertain; but, judging
from the eight tubercular plates still remaining in an imperfect column, and estimating the
number necessary to complete the same, it is probable that the perfect test had from
twelve to fourteen tubercles in each row, gradually increasing in size from the peristome
upwards ; they are proportionately small when compared with the size of the test itself.
The areolas are oblong, and the narrowness of the plates causes them to open into each
other above and below ; the bosses are neither large nor prominent, but the crenulations
on their summits (PI. I, fig. 1 4) form a well-marked circlet of granules, which surrounds
the base of the tubercles (fig. 1 ¢); these are small, with deep and wide perforations on
their summits. The peristome is wide, and, in the only three specimens we know, part
of the dental apparatus is preserved 7x sifu : the portion remaining in the figured specimen
consists of three prominent jaws (fig. 1 a); one of these is shown in fig. 1 g. It is convex,
and the external surface is streugthened by three prominent ridges ; the teeth are large,
but are all fractured. As the test rests on its upper surface, the ovarial plates and dorsal
surface are concealed from observation.

The spines remaining zz s¢¢u on the test are of two kinds (fig. 1 a); those articulated
with the primary tubercles, the primaries ; and those articulated with the smaller tubercles,
the secondaries. The primary spines exhibit a peculiar structure (fig. 17); the head is
large, gradually increasing in diameter from the articular cavity to the circular band ;
the rim of the acetabulum is coarsely and deeply crenulated, and the raised band is nar-
row, prominent, and finely milled; the neck tapers gradually from the band to the point
where it joins the stem, which has the same structure as the head; and the surface is
delicately sculptured with fine longitudinal lines (fig. 1 /).

The stem is united to the neck by an oblique harmonia suture; in those spines which
are denuded of their external layer, it has a horny semi-transparent aspect; but when
this external layer is present, its surface is seen, with a pocket lens, to be sculptured with
fine longitudinal lines; besides these, there are a number of small processes arranged in
rows, the points of which have a direction forwards, but their linear arrangement is by no
means regular; the stem is long, slender, and circular, its length in proportion to the
diameter of the test has not been ascertained, as all the spines are fractured. The
secondary spines are very uniform in size and structure, and are preserved in abundance
im the specimen before us (fig. 1 a). Hach of the minute tubercles of the ambulacral
areas, and of the miliary zones, carried one of these spines, which measure about = ths to
zoths of an inch in length; they are stout and blunt pointed, tapering very little from
the milled band to the apex, and having their surface covered with microscopic longitudinal
lines (fig. 1 d, e).

Affinities and differences. —This Cidaris belongs to the same group as Cidaris Fowler,

ECHINODERMATA. 29

Wright, and Cidarites maximus, Minster, but it presents many important characters by
which it is distinguished from both. From Cidaris Fowleri it differs in wanting the
regular close-set row of marginal granules, with the four internal rows of minute granules
in the ambulacral areas, which form so fine a character in that Inferior Oolite species
(Pl. I, fig. 4¢) ; the irregular distribution of the small tubercles in these areas in Cidaris
Fdwardsii forms a marked distinction between them: the poriferous zones are occupied
by large pores, separated from each other by thin septa; in Cidarts Mowleri the pores are
small, oblong, and separated by a thick portion of the test (fig. 4¢). The tubercular
plates in Cidaris Edwards being narrow, there are consequently a greater number of
primary tubercles in the inter-ambulacral areas: the areolas, likewise, are oblong, and
always confluent in the vertical direction; whereas in Cidaris Fowleri the areolas are
nearly circular (fig. 4), and each is surrounded by a circle of granules. The inter-
tubercular space or miliary zone in Cidaris Hdwardsu is filled with small perforated
tubercles, but in Cidaris Fowlert the same space is occupied by small imperforate granules,
more numerous, but less regular in size and distribution (fig. 4.e): the spines in Crdaris
Fowleri are stout, and have well-developed rows of forward-directed prickles (fig. 4 d) ;
whereas in Cidaris Hdwardswi they are long and slender, with small irregular elevations of
the surface, which is likewise sculptured with microscopic longitudinal lines.

Locality and Stratigraphical position —This fine urchin was discovered in the upper
shales of the Lower Lias, or Middle Lias, by G. E. Gavey, Esq., C.E., at Mickleton tunnel,
near Chipping Campden, in the zone of that formation containing Ammonites maculatus,
Young and Bird. The bed which yielded Cidaris Hdwardsiw contained likewise other
species of Echinoderms in a fine state of preservation: these were—

Cidaris Edwardsu, Wright Tropidaster pectinatus, Forbes
Hemipedina Bowerbanku, Wright, | Ophioderma Gaveyt, Wright

" plates of Latracrinus robustus, Wright

Uraster Gaveyt, Forbes es '‘I'wo species undetermined.

Besides these Echinodermata, 40 species of Conchifera, 8 species of Gasteropoda, and
10 species of Cephalopoda, with Serpule, and 2 new species of Pollicipes, were associated
with the same. For more details, the reader may consult Mr. Gavey’s paper.* Isolated
plates of Cidaris Hdwardsit have been collected from the same zone of the Lias in other
localities in Gloucestershire, but the specimen we have figured is the only one which
displays the true character of the species. Professor Morris has kindly communicated a
Cidaris with spines, collected from the Lias at Lyme Regis, which has proved to be a small
specimen of Cidaris Hdwardsii: this beautitul fossil shows many of the long slender

* «Quarterly Journal of the Geological Society,’ vol. ix, p. 29.

30 CIDARIS.

spines iz situ on the slab. Like the specimen we have figured, it lies crushed upon its
upper surface; the mouth-opening contains some of the jaws and teeth. A crushed
Cidaris, on a slab of Lower Lias shale, from Brockeridge Common, Gloucestershire,
has been communicated by Professor Buckman. The areolas in this specimen are
oblong, and some of them are entirely surrounded by a scrobicular circle of small, close-
set granules, whilst a few only are confluent. The character of the bosses, however, with
their flat, deeply-crenulated summits, and small, perforated tubercles, convince me that
it is Cidaris Edwards. Wad a doubt existed, it would have been removed by the
discovery of one of the primary spines laid along the concealed portion of the test,
which exhibited the crenulated head and milled neck, with longitudinal lines, so very
characteristic of this Middle Lias urchin. ‘The entire confluence of the areolas in the
large specimen may prove to be an adult character; as the crowding together of so many
tubercles in each column of tubercular plates, may have necessitated the absorption of
a portion of the scrobicular circles, which existed in juvenile individuals. On this
interesting slab there are two separate vertebree of an Ichthyosaurus. Professor Phillips, in
his ‘Geology of Yorkshire,’ figures a spine, Pl. XIII, fig. 17, which resembles those of
our urchin, but its characters are not given in detail. Goldfuss* mentions spines, which
he erroneously referred to Cidaris Blumenbachu, that were collected from the “ Gryphi-
tenkalke der Lias-Formationen bei Pretzfeld und Theta, und ist der einzige Hchinit, der
in Baiern dieser Formation angehort.” One of the “ aculeorum varie forme fragmenta”
(i, fig. 4, Pl. XX XIX) so very much resembles the spines attached to the test of Cidaris
Edwardsii, that it is possible it may be the same. Quenstedt} has found spines in the
Lias, “am Donau-Mainkanal bei Dorlbach,” one of which (Pl. XLVII, fig. 80) resembles
those of our species. Another spine, from the Inferior Lias of Dasslingen, Wurtemberg
(figs. 31, 32), has fine longitudinal lines, with small wart-like eminences, not arranged in
rows. All these Liassic urchins present nearly allied characters, and prove that Cidarites,
belonging to the same natural group, and if not to the same, at least to allied species
of the genus Cidaris, lived over an extensive area during the deposition of the upper
shaly beds of the Lower Lias, or the Middle Lias of Continental geologists.

In the Scarborough Museum I found a beautiful specimen of this species, with many
spines attached, as Jarge as the one figured in this Monograph. It was collected from
the Middle Lias of the Yorkshire coast.

This species is dedicated to Professor Milne Edwards, of the Museum of Natural
History at the Jardin des Plantes, Paris.

* «Petrefacta Germania,’ vol. i, p. 117, tab. 39, fig. 4 e—A.
+ ‘Handbuch der Petrefaktenkunde,’ p. 574, pl. 48, figs. 23—32.

ECHINODERMATA. 31

Ciparis InminstErensis, Wright, n. sp. Pl. V, fig. 6 a, d.

Test large, form unknown; ambulacral areas narrow, with two marginal rows of small
granules; poriferous zones narrow, pores nearly round, and closely approximated ; inter-
ambulacral plates large, as deep as they are wide; areolas large, circular, surrounded by
a complete scrobicular circle of small granules; mammary bosses not much elevated ;
summits deeply crenulated ; tubercles of moderate size.

Description —We only possess, of this species, one tubercular plate, and a portion of
a second, with one half of the corresponding part of the ambulacral area, but still this
fragment is sufficient to enable me to give its diagnosis, and point out those characters by
which it is distinguished from its congeners. The test must have attained a size quite
equal to that of Cidaris Fowler; the ambulacral areas are very narrow, and have only
two rows of marginal granules, there being one granule on each alternate plate; the
poriferous zones are narrow, the holes are contiguous and nearly round, and each pair has
a thin septum separating them (Pl. V, fig. 6 4) ; there are fifteen pairs of holes opposite
each large inter-ambulacral plate.

The inter-ambulacral areas are composed of large, nearly quadrate, tubercular plates
(fig. 6 4); the number of the primary tubercles is unknown; the areolas are large and
circular, and are surrounded by a scrobicular circle, composed of very small granules
(fig. 6 6); down the inter-tubercular space there were other four rows of granules of nearly
the same size; the scrobicular circle extends so very near to the poriferous zones, that there
is no granular space intervening between them (fig. 6 6); the mammary boss is not
very prominent, but its summit is sculptured with well-defined crenulations ; the tubercle
is of moderate size, and has a wide perforation in its summit.

Affinities and differences——This species differs from Cirdaris Edwardsii in having a
complete scrobicular circle of granules around the areolas, in the narrowness of the ambu-
lacral areas, with only two marginal rows of granules, and in the scrobicular circle abutting
against the poriferous zones without a row of granules separating them; the smallness of
the holes in the zones, and their proximity to each other, is another point of difference.
Compare PI. I, fig. 1 4, with Pl. V, fig. 6 4.

Cidaris Ilminsterensis differs from Cidaris Fowleri in having no granules between the
scrobicular circle and the zones, the latter having two or three rows (fig. 4 e, Pl. I); the
breadth of the ambulacra, and its four rows of granules, and the wide poriferous zones,
with the holes kept far apart by very thick septa, serve further to distinguish that
Inferior Oolite form from this Upper Lias species.

Locality and Stratigraphical position—It was collected by Mr. Moore in the Upper

32 CIDARIS.

Lias of Ilminster, and was found associated with Ammonites serpentinus, Schlotheim,
Ammonites annulatus, Sowerby, and other Upper Lias fossils. The fragment figured was
the only one ever found.

B. Species from the Inferior Oolite.

Ciparis Fowxrri, Wright. Pl. I, fig. 4 a, 4, ¢, d, e.

Crparis coronaTa. Murchison’s Geology of Cheltenham, 2d ed., by Buckman and

Strickland, p. 73.

— — Morris’s Catalogue of British Fossils, Inf. Oolite, Cotteswold Hills,
Ist ed., p. 49.

— Fowtert. Wright, Annals and Magazine of Natural History, 2d series, vol. viii,
p- 246, pl. 11, fig. 5 a, 6.

— — Desor’s Synopsis des Echinides Fossiles, p. 6, tab. 3, fig. 13.

— — Morris’s Catalogue of British Fossils, 2d ed., p. 74.

Test spheroidal, depressed at both poles; ambulacral areas prominent, flat, narrow,
and slightly undulated, with two marginal rows of small, equal-sized, close-set granules,
and two rows of central, irregular, and almost microscopic granules, with still smaller
granules interspersed between them; poriferous zones broad, each as wide as the ambu-
lacra; pores oblong, set wide apart, with a thick septum between the two pores of each
pair; inter-ambulacral areas with two rows of primary tubercles, six to eight in each row,
all the areas surrounded by a complete scrobicular circle of granules; miliary zone wide,
filled up with small close-set granulations; spines large, covered with irregular rows of
forward-directed prickles.

Dimensions.—Height one inch and one tenth, transverse diameter one inch and
eight tenths ; two crushed specimens, the relative dimensions of which, therefore, cannot be
accurately ascertained, measure considerably more.

Description —This beautiful Cidaris, which, when first discovered, more than fifteen
years ago, was supposed to be the Czdaris coronata, Goldfuss, and was catalogued as such
in the works cited in the synonyms of the species. Apart from the organic characters to
be pointed out in the sequel, it is a form which has hitherto only been found in the
Inferior Oolite, whilst Crdaris coronata, Golaf., as constantly characterises the upper
zone of the middle division of the Jurassic group. In the Swiss Jura, for example, it is
found in the “terrain a chailles,” a local formation, the greatest similarity to which, it
appears, is the lower Caleareous Grit of England; in the Coral Rag, or Argovien, of
Randen, of Birmansdorf, of the valley of the Birse, and of the same stage in Bavaria and

ECHINODERMATA. 33

Wurtemberg. It is found likewise in the Coral Rag of Besancon, in the Corallian stage
at Chatel-Censoir, and at Druyes, Yonne, in Ain, Isere, and other departments of France.
On the Continent Cidaris coronata is therefore a characteristic Coral Rag urchin ; but it
has never yet been found in this or any other stage in England.

The ambulacral areas in Cidaris Fowlert are slightly prominent and undulated ; they
are nearly uniform in width throughout, and are furnished with two marginal rows of
nearly equal-sized, close-set granules (PI. I, fig. 4 e), which become larger near the peris-
tome ; within these marginal pairs are two other rows of smaller granules, with other
microscopic granulations interspersed among them; these inner rows gradually disappear
above and below, and the marginal rows then come into juxtaposition; the poriferous
zones form wide ribbon-like depressions, nearly equalling in breadth that of the area
(Pl. I, fig. 4 e); the pores are oblong, and the holes forming a pair are set widely apart,
with a thick septum, equalling the long diameter of the pores, separating them from each
other. In the large specimens there are seventeen pairs of pores opposite each of the large
tubercular plates.

The inter-ambulacra] areas are formed of large plates, nearly as broad as they are long
(Pl. I, fig. 4 4), their lines of sutures beimg very distinct in young as well as in old
individuals ; each column consists of from six to eight tubercular plates, and each plate
externally has a large flat, nearly circular areola (PI. I, fig. 4 e), slightly furrowed towards its
outer border; mm the centre rises abruptly the mammillary boss, the summit of which is
sculptured with about fifteen deep crenulations; from the interior of these rises a short
cylindrical stem, which terminates in a small hemispherical, deeply perforated, spinigerous
tubercle, the diameter of the tubercle slightly exceeding that of its stem; the margins
of the areolas are bounded hy a circle of fifteen scrobicular granules (fig. 4 ¢), which
are arranged with much regularity, each granule having a microscopic circlet of granulets
around its base; the scrobicular circles on the upper half are more fully developed than
those on the lower half of the test; from the equator upwards, each areola has its own
distinct scrobicular circle; but from that line to the peristome, one scrobicular line of
granules separates two areolas above and below from each other; the miliary zone is wide,
and is thickly covered with very small granules, which diminish in size from the scrobicular
circle to the median suture; among the principal granules fillmg up this interspace are
others of still smaller size; the entire granulation does not observe much regularity,
although it follows lines which somewhat describe the tract of the median suture: the
space between the scrobicular circle and the poriferous zones is not so wide as that
between the scrobicular circle and the centro-sutural line; this space is ikewise filled up
by granulations of the same size and character as those which fill up the median miliary
zone.

The mouth opening measures half the diameter of the test at the equator, and the
peristome has a pentagonal form. (Pl. I, fig. 4a.) In two of the specimens before us, the
lantern is preserved, consisting of five strong pyramidal jaws, armed with conical teeth.

5

34 > CIDARIS:

(Pl. I, fig. 4a.) The plates composing the apical disc are absent in all the specimens
hitherto found.

The spines (PI. J, fig. 4 ¢) are large; the milled band below the neck is close to the
cup-like articulating cavity ; the neck increases slightly in thickness, and the nearly round
stem is covered with longitudinal rows of short, sharp prickles, which have their points
directed forwards; the stem of the spine is slightly flattened. Fortunately one specimen
was found by Mr. Gibbs, of the Geological Survey, with the spine zz sztw attached to the
test, so that all doubt about the species to which it belongs is removed by this discovery.
The specimen with the spine attached is in the Geological Museum im Jermyn Street.
The secondary spines are short, and blunt pointed, but only a very few of these have been
found. Those belonging to the scrobicular circle are larger than those which armed the
small granules.

Affinities and differences.—This urchin very much resembles an undescribed species
collected by M. De Loriere, from the Inferior Oolite of the department of the Sarthe. There
are some slight shades of difference between the French specimens and Cidaris Fowleri,
but the general resemblance between them is so very great, that we believe them to be
identical. The rock from which the French urchin was collected is referred to the “ étage
Callovien ;”’ but it contains several species which hitherto have only been found by us in
the Inferior Oolite of England, as Molectypus gibberulus, Agassiz, Pygurus depressus,
Agassiz, and Clypeus Agassiz, Wright. From these facts we are disposed to think that
there must be a mistake about the true stratigraphical position of the formation from
whence these urchins have been collected.

In the general structure of the test, and in its ornamentation, Cidaris Fowleri closely
resembles Cidaris Orbignyana, Agassiz,* from the Kimmeridge Clay of Havre. If the
palzeontologist had to decide the species from the anatomy of the test alone, he would have
great difficulty in distinguishing the one form from the other; but fortunately the
spines of both are now known, which settles the question as to the specific difference
existing between them. We have the test and spines of Crdaris Orbignyana before us,
but the reader will find fine figures of both in M. Desor’s Synopsis, where it is admirably
figured for the first time, and to this work we beg to refer the reader. Compare, for
example, Pl. III, fig. 18, spine of Codarts Fowleri, with Pl. VIII, figs. 7—9, the spine of
Cidaris Orbignyana.

In the general form and structure of the test, Cedaris Fowler: resembles Crdaris flori-
gemma, but it differs from that well-known Coral Rag species in the flatness of its ambu-
lacral areas, in the greater breadth of the poriferous zones, its smaller primary tubercles,
the depth and character of the crenulations on the bosses, and, above all, in the structure
of its spmes. Compare Pl. I, fig. 4d, with Pl. II, fig. 2 a.

* A beautiful figure of this fine species is published in M. Desor’s ‘Synopsis des Echinides Fossiles,’
pl. 1, fig. 3; pl. 8, figs. 7—9, contains the spines.

ECHINODERMATA. 35

It is distinguished from Cidaris Edwards by the width of the poriferous zones, and
the thickness of the septum which separates the pores composing a pair; by the circular
form of the areas, and the complete scrobicular circle of granules that surround and
hmit them in Cidaris Fowleri: whereas in Cidaris Edwardsii the areolas are oblong and
confluent. In the structure of the spmes there are likewise important differences.
Compare Pl. I, fig. 1 7, with fig. 4 d.

Cidaris Fowleri is distinguished from Cidaris Bouchardii (P1.I, fig. 2 a, 6, and Pl. VIII,
fig. 3 a, 6,c), which occurs with it in the same bed, by the latter being in general a rather
more depressed form, its ambulacral areas having only two marginal rows of granules;
the poriferous zones being much narrower, and the areolas of the primary tubercles
more deeply sunk in the plates; the tubercles themselves are larger, the scrobi-
cular circle is more prominent, and the granulations in the miliary zone are fewer and
larger.

Cidaris Fowleri differs from Cidaris Wrighti (P1. I, fig. 3), which is likewise found
rarely in the Pea Grit, by the latter having a very thick test, large primary tubercles, with
very small perforations ; the poriferous zones are narrow, and the ambulacral areas have
only two rows of marginal granules (fig. 3c). Moreover, it is a much smaller and a more
inflated form than Cidaris Fowlert.

Only one tubercular plate of Cidaris Ilminsterensis from the Upper Lias (Pl. V,
fig. 6 a, 6) is known; but so finely are the specific characters defined upon that fragment,
that we are enabled to point out the differences between these two species, so nearly
related to each other in time. In Cidarts Itminsterensis the scrobicular circle of granules
abuts very close upon the poriferous zones, which are narrow, and have the pores placed
close together; whereas in Cidaris Fowleri there is a considerable granulated space
between the scrobicular circle and the poriferous zones, which are wide, and have their
pores placed far asunder.

Locality and Stratigraphical position—Cidaris Fowler: was obtained from the Pea-
grit of the Inferior Oolite at Crickley Hill, Gloucestershire. It has been likewise found
in the same bed at Birdhp and Leckhampton Hills. The remarkable rock in which
these Cidarites are found seems to have been a tranquil littoral deposit in shallow water,
as the most of the Echinoderms are finely preserved, with all the sharpness of their
sculpture quite intact. Associated with this urchin are—

Cidaris Bouchardii, Wright Hemipedina Bakeri, Wright
Cidaris Wrightii, Desor Hemipedina perforata, Wright
Diadema depressum, Agassiz Hemipedina tetragramma, Wright
Echinus germinans, Phillips flemipedina Waterhousei, Wright

Polycyphus Deslongchampsui, Wright Hlemipedina Bonei, Wright

36 CIDARIS.

BRACHIOPODA.

Terebratula simpler, Buckman. (Terebratula trigonalis, Lhwydd.)
Terebratula plicata, Buckman.
Terebratula submaxillata, Davidson.

CEPHALOPODA.

Ammonites corrugatus (Murchisone), Sowerby.

This species is dedicated to our friend, Charles Fowler, Hsq., who generously added to
our collection the fine specimen figured in detail.

Ciparis Bovcnarpu, Wright. Pl. I, fig. 2 a, 6, c; Pl. VIII, fig. 3 a, 3, c.

CIDARIS ELEGANS. Morris’s Catalogue of British Fossils, Ist ed., p. 49, 1843.
— Boucuarpil. Wright, Annals and Magazine of Natural History, 2d series, vol. xiii,
p. 163, pl. 11, fig. 2.

Test circular, much depressed; ambulacral areas narrow and flexuous; poriferous
zones deep and narrow; inter-ambulacral areas with two rows of primary tubercles, six to
seven in each row; areolas circular, deeply excavated, and entirely surrounded by an

elevated scrobicular circle of large granules; a zigzag depression extends through the
centre of the inter-ambulacral areas ; centro-sutural line strongly marked.

Dimensions.—A large specimen: Height, nine tenths of an inch; transverse diameter,
one inch and seven tenths. A moderate-sized specimen: Height, eleven twentieths of
an inch; transverse diameter, one inch and two tenths.

Description.—This beautiful urchin was entered in the Catalogue of British Fossils as
Cidaris elegans, Goldfuss. A comparison, however, of several individuals of Cidaris
Bouchardii, with typical specimens of Goldfuss’s species, kindly sent us by our friends,
Prof. Roemer, of Bonn, which he had identified with the original Cedaris elegans, Goldf.,
in the Bonn Museum, and Dr. Fraas of Stuttgard, has enabled us to separate these two forms.

The test of Cidaris Bouchardu is circular, and much depressed, from the great flatten-
ing of both of the upper and under surfaces; the ambulacral areas are narrow, and much
undulated ; they have two marginal rows of small granules, with a few more minute ones
scattered irregularly between them; the poriferous zones are narrow and slightly sunk ;
the holes are circular and contiguous, and are separated by a prominent granule rising
from the surface of the septum. (PI. I, fig. 2 c.)

The inter-ambulacral areas are five times the width of the ambulacral (PI. I, fig. 2 a, 4, ¢ ;
Pl. VIII, fig. 3 a, 6); the primary tubercles are small, and from six to seven in each row ;

ECHINODERMATA. 37

the areolas are circular and deeply sunk (fig. 2c); around the margin of each there is a
complete elevated scrobicular circle of small close-set granules; the mammary boss rises
abruptly from the centre, and its summit is sharply crenulated ; the tubercle is propor-
tionately small, and deeply perforated with a small hole; the elevation of the scrobicular
circle gives an excavated air to the areolas of this species, and produces, at the same time,
a marked zigzag depression down the centre of the areas; the miliary zone is wide, and
filled with six rows of fine granules, rather smaller in size than those forming the
scrobicular circles.

The mouth opening is small, being less than one half the diameter of the test. Ina
small specimen measuring 33ths of an inch in diameter, that of the peristome was a little
more than ths of aninch. This opening lies in a slight depression of the under surface ;
the peristome has a pentagonal form; and the ambulacral areas retain their full diameter
to the margin of the same.

The apical disc is absent in all the specimens; but the dimensions of the aperture
occupied by these plates is very considerable, being more than half the diameter of the
test. In a small individual before us, measuring 4$ths of an inch in diameter, the diameter
of the opening for the apical disc measures ths of an inch. In this small specimen, in
fine preservation, which we collected in Dorsetshire, the margin of the discal opening is
entire, so that we can state with certainty its comparative measurement, with that of the
equatorial diameter of the test itself. It is the only individual that has afforded this
information, all the others being more or less crushed, broken, or otherwise distorted.

Affinities and differences.—Cidaris Bouchardii has been mistaken for, and registered
as Cidaris elegans, Goldf., but, although it has some affinities with that species, its dif-
ferences are numerous and important. The ambulacral areas in both species have two
rows of marginal granules, and the poriferous zones in both are of about the same width
and depth. In the inter-ambulacral areas the differences are conspicuous: the number of
tubercles is greater in Cidaris Bouchardii than in Cidaris elegans ; and the sunk areolas,
with their elevated scrobicular circle, form another important distinction between our
urchin and the German form. ‘The tubercles, moreover, are larger and much more pro-
minent in Cidaris elegans : it likewise belongs to a Iigher stratigraphical zone, the speci-
mens before us having been found in the Coral Rag of Streitberg and Sigmaringen.
Another fact, of a negative character it is true, but not the less valuable in palzontological
investigations, is this, that we have never seen spines at all approaching the curious and
singular character exhibited by those of Cidaris elegans im the Inferior Oolitic rock, from
whence our urchins have been collected.

Cidaris Bouchardii resembles Cidaris coronata, Goldf., in many points. It has the
depressed form, the flexuous ambulacra, and the prominent scrobicular circle of this German
species, but is distinguished from it by the following characters: The equatorial portion of
the ambulacral areas in Cidaris coronata has four rows of granules, which diminish to two

38 CIDARIS.

rows, above and below ; these areas, therefore, are enlarged in the middle, and taper towards
the peristome and towards the apical disc, whereas in Cidaris Bouchardii they retain
very nearly a uniform width throughout. There are seldom more than four tubercular
plates in each column in Cidarts coronata; whereas in Cidaris Bouchardi, although a
small species, the numbers are from six to seven. In Cidaris coronata the scrobicular
circles of the upper tubercular plates are separated by a considerable granulated space,
whereas in Cidaris Bouchardii the scrobicular circles are contiguous; the granules of the
scrobicular circles are likewise larger and more spaced out in Crdaris coronata than in
Cidaris Bouchardit, and the primary tubercles are proportionately larger in the former.
Although both urchins have zigzag depressions down the centre of the inter-ambulacral
areas, in Cidaris coronata the miliary zone is much wider, and covered with larger granules.
The poriferous zones are sunk in very deep depressions in Cidaris coronata, arising from
the prominence of the granules on the ambulacral and inter-ambulacral areas, but these
zonal depressions are not so deep in our species.

Cidaris Bouchardit resembles Cidaris propinqua, Minster, only in the depressed form
of the test. In all other points it is sufficiently distinct from that species. In Cidaris
propinqua there are four primary tubercles in each column of tubercular plates; and those
on the upper surface are very large in proportion to the size of the test ; their areolas have
entire scrobicular circles of large spaced-out granules, which are closely contiguous; the
ambulacral areas aré much flexed, and have two rows of close-set marginal granules ; the
poviferous zones are slightly sunk, and have very small holes. The spines of Crdaris
propingua have an elliptical-shaped body, covered with longitudinal rows of small tubercles,
and united together by connecting calcareous threads.

Cidaris Bouchardi resembles Cidaris marginata, Goldf., in the depressed form of the
test, and in having, like it, deep sunk areolas, with a wide, depressed, much granulated
miliary zone, between the primary tubercles; but it is distinguished from Cidarts margi-
nata in having narrower ambulacral areas, with only two rows of granules; whilst Cidaris
marginata has four rows throughout. ‘The primary tubercles are likewise smaller, and
their bosses are sharply crenulated; whilst in Cidaris marginata they are smooth and
uncrenulated. This magnificent Coral Rag German urchin is, moreover, a much larger
form than our species from the Inferior Oolite.

Locality and Stratigraphical position.—This is a very rare urchin, and was discovered
by us about three years ago in the Pea Grit of the Inferior Oolite of Birdlip and Crickley
Hills. Since Pl. I was finished, we have obtained the finest specimen yet known, which
presents many points of importance that are not shown in our earlier found specimens.
This urchin is figured in Pl. VIII, fig. 3 a, 6, c. We collected, with Dr. Syme, Cidaris
Bouchardii in the Inferior Oolite near Bridport, Dorsetshire, in beds which are equivalent
to the Upper Ragstones of the Inferior Oolite of Gloucestershire. The Dorsetshire speci-
mens were associated with Collyrites ringens, Collyrites bicordatus, and Olypeus altus, being

ECHINODERMATA. 39

all species belonging to that zone of the Inferior Oolite which contains Ammonites
Parkinsont, Sow., and Ammonites subradiatus, Sow. Some separate plates of an urchin
collected with spines from the Bradford Clay, near Tetbury-road Station, Great Western
Railway (PI. V, fig. 7 a, 6), closely resemble this form; but no entire test of this Cidaris
has been found, and it is doubtful whether or not it is distinct from Cidaris Bouchardii.
We dedicate this urchin to our friend M. Bouchard Chantereaux, of Boulogne-sur-Mer,
to whom we are indebted for some beautiful and rare Jurassic Echinoderms and other
fossils, sent by him in the kindest manner to aid us in the production of this Monograph.

Ciparis Wricurit, Desor. Pl. I, fig. 3 a, 6, ¢, d,e, f.

CIDARIS PROPINQUA. Wright, Annals and Magazine of Natural History, 2d series, vol. viii,
p- 250, pl. 11, fig. 6.
— Wricutit. Desor’s Synopsis des Echinides Fossiles, p. 7.

Test thick, circular, inflated, not much depressed at the poles; ambulacral areas very
narrow, sinuous, and furnished with two rows of close-set marginal granules through-
out ; the inter-ambulacral areas have six tubercles in each column of plates; the tubercles
are large, and slightly perforated; the upper mammillary bosses only are crenulated ;
the areolas are surrounded by complete scrobicular circles of small, prominent, well-
spaced-out granules; apical disc unknown; spines never found attached to the test.

Dimensions.—Height, six tenths of an inch; transverse diameter, 1 inch.

Description.—When this urchin was found, five years ago, we were then unable to
compare it with a type specimen of Cidaris propinqua, Minster. A subsequent com-
parison with the German species has convinced us that we were mistaken in our deter-
mination, and it has long lain marked as a new species in the trays of our cabinet. M.
Desor, in his ‘Synopsis des Hchinides Fossiles,’ has likewise detected the difference
between this species and Cidaris propinqua, and justly observes—“ Petite espéce voisine
du Cid. propinqua, mais plus renflée; les tubercules paraissent aussi étre moins gros.
Ambulacres trés étroits, composés de deux rangées seulement de granules.”* ‘This
rectification removes another of those apparent exceptions to the law which regulates
the distribution of species in time and space, for it is now evident that no species of
Echinoderm is common to the Inferior Oolite and Coral Rag of England; but, on the
contrary, that both these formations are characterised by distinct and well-defined species

of this class.
The test of Cidaris Wrightit is very thick for so small a species. It is inflated at the

* ¢Synopsis des Echinides Fossiles,’ p. 7.

40 CIDARIS.

sides, and not much depressed at the poles (Pl. I, fig. 3 a, 6); the ambulacral areas are
very narrow and sinuous, having two rows of small, equal-sized, close-set granules arranged
on the margins thereof; the poriferous zones are rather deeply sunk, from the promi-
nence of the ambulacral granules, and those of the scrobicular circles, which extend to the
zones ; the pores are round, and the septa between the pores are about the thickness of
the diameter of one of the holes: there are thirteen pairs of pores opposite one inter-
ambulacral plate. (Pl. I, fig. 3 c.)

The inter-ambulacral areas, at the equator, are five times the width of the ambulacral ;
each tubercular column consists of six plates, which support very large, prominent tubercles ;
the areolas are circular, and surrounded by a complete scrobicular circle of promiment, well-
spaced-out granules (fig. 3c); the mammillary bosses are small; the summits of the three
inferior mammee are smooth and destitute of crenulations, those of the two or three upper
ones are feebly crenulated; the tubercles are disproportionately large to the size of the
bosses, and even of the test itself; they are hemispherical eminences terminating a stout
stem, and all their perforations are in the form of oblong slits; the size and prominence
of the tubercles form an excellent diagnostic character for this species; the scrobicular
circle consists of fourteen small, round, prominent granules, raised on little basal
eminences, and forming a distinct beaded wreath around each areola (fig. 3 c).

The mihary zone, between the two rows of tubercles, is slightly concave; it does
not extend throughout to the apical disc, im consequence of the large upper tubercles
encroaching on each other; in its widest part it is filled with three rows of granules, much
smaller in size than those forming the scrobicular circle.

The mouth opening is circular, about one half the diameter of the test at the equator ;
the primary tubercles near the peristome are well developed, and very prominent ; they
increase gradually in size towards the upper surface; the opening for the apical disc is of
moderate dimensions.

The spines which are referred to this species (PI. I, fig. 3 d, e) belong to the same
group as that to which Czdaris florigemma belongs. ‘They are from an inch and a
quarter to an inch and a half m length; the stem swells gently outwards towards its
inferior third, and then tapers to the extremity; it is covered with longitudinal rows of
granules, united together by lines of calcareous threads (fig. 3,f), which shows the surface
of the spine enlarged several diameters. As these spines have not been found attached to
the test, it is only the smoothness of the acetabulum, and the similarity in size, that gives
probability to the supposition that they really belonged to the test to which we have pro-
visionally assigned them. As many grave errors have been committed by assigning spines
to tests to which they never belonged, we caution the reader, that unless spines have
been found on the test, or 2 sétw on the tubercles thereof, we must treat the supposition
of their belonging to the same individual as a question of doubt.

Afinities and differences.

Cidaris Wrightii resembles Cidaris propingua in the dis-

ECHINODERMATA. Al

proportionate size of its tubercles to that of the test, and in having some of the bosses
smooth, and others feebly crenulated, but it is distinctly separated from that form by
having six plates in the tubercular columns, Cidaris propinqua having only five; the test
is more globular and inflated, the areolas are smaller, the circles of scrobicular granules are
not so prominent, and the tubercles are more crowded together; the spines of Cidaris
Wrightii ave larger in proportion to the diameter of the test than in Cidaris propinqua ;
their stems are smaller, and taper more, and the rows of tubercles are not very prominent ;
whereas in Cidaris propinqua the stems of the spines are thick and elliptical, and the
tubercles are large and bead-like on their surface.

Cidaris Wrightii is distinguished from Cidaris Bouchardi, with which it is associated
in the same bed, by its globular and inflated test, the size of the tubercles, and the shal-
lowness of the areolas; Cidaris Bouchardii having a depressed test, with small tubercles,
and deeply sunk areolas.

From Cidaris Fowler: this species is distinguished by the size and prominence of the
tubercles, the narrowness of the ambulacral areas and poriferous zones, and the greater
proportionate height and inflation of the test; the ambulacral areas in Cidaris Fowleri are
broad, with four rows of small granules; and the pores in the poriferous zones are wide
apart. ‘The spines in these two associated species are likewise very different; those of
Cidaris Fowleri ave oval, and covered with irregular rows of small spines ; whilst those of
Cidaris Wrightit have regular longitudinal rows of small tubercles.

Cidaris Wright has many points of affinity with Czdaris florigemma, both as regards
the general structure of its test and the form and decoration of its spines; but it is
distinguished from that Coral Rag form in having larger tubercles and smaller areas,
with a much wider granulated miliary zone between the primary tubercles. The
spines assigned to Cidaris Wrightit belong to the same group as those of Cidaris flori-
gemma, but the stem is longer and narrower, and the granules forming the rows are set
closer together, and not so prominent as in Cidaris florigemma, where they form lines of
tubercles very distinct from each other. Although connected by delicate calcareous threads,
the apices of the tubercles are likewise directed forwards, and the summit of the stem
terminates in a truncated star-like extremity. (Pl. I, fig. 3 e.)

Locality and Stratigraphical position.—This is a very rare Cidarite. ‘Three specimens
only have been found by me in the Pea Grit of Crickley Hill, which are all more or less im-
perfect ; and I have never seen an example in any other cabinet. An urchin found in
the Stonefield Slate at Hyeford, Gloucestershire, is referred to Cidaris propinqua. Whether
this is identical with Crzdaris Wrightii I have no means of judging, not having seen
the type specimen catalogued under that name.

History.—It was first figured in my ‘ Memoir on the Cidaridz of the Oolites,’ and
subsequently entered in M. Desor’s ‘Synopsis des Echinides’ under the name it now bears.
6

42 CIDARIS.

CipaRis CONFLUENS, Forbes, MS.

CIDARIS CONFLUENS. Morris, Catalogue of British Fossils, 2d edition, p. 74.
= — Woodward, Memoirs of the Geological Survey, Decade V, Note on
species of Cidaris.

The specimen consists of four consecutive plates, of nearly equal size, from one of the
inter-ambulacral rows. ‘The set measures one inch in length and half an inch in width.
The areolas are oblong and excavated, with acute lateral margins, but they are all confluent
above and below; the bosses have broad, prominent, deeply crenulated summits; the
tubercles are small, and widely perforated ; the lateral borders of the plates supported
small granulations. ‘The spines imbedded in the same rock were long, cylindrical, and
longitudinally striated; their surface was armed, at intervals, with short, stout, forward-
directed prickles. ‘The ambulacral areas are absent; and the surface of the plates is so
much weathered, that I did not consider it necessary to figure the specimen.

This fragment resembles very much Cidaris Lorierii, Wright, from the étage Bajocien,
or Inferior Oolite, of the department of the Sarthe (a description of which will be found in
the notes of foreign species of the genus Cidaris), but the weathered and fractured
condition of the fragment renders it impossible to make a more correct diagnosis until
better specimens are found.

Locality and Stratigraphical position—The specimen belongs to the Museum of
Practical Geology, Jermyn Street; and was obtained from the Inferior Oolite, near Frome,
Somersetshire.

C. Species from the Bradford Clay.

Crparis Braprorpgnsis, Wright. Pl. V, fig. 7 a, 4, ¢, d.

Form and size unknown; ambulacral areas narrow, with two rows of marginal
granules ; inter-ambulacral plates thick, areola circular, boss prominent, summit feebly
crenulated, tubercle large; a complete scrobicular circle of fifteen large granules around
the areola; miliary zone concave, with six to eight rows of granules; the spines, associated
with the plates, have the acetabulum small, the neck long and smooth; the stem elliptical,
and covered with waved lines of granules, neither uniform in size nor arrangement.

Description—The meagre materials at my disposal, illustrative of this urchin, only
permit me to give a very imperfect diagnosis of this Oolitic form, which I at one time

ECHINODERMATA. A3

thought was identical with Cidaris Bouchardii ; but on making a careful examination of
the ambulacral and the inter-ambulacral plates, the only portions of the test I have seen
with those of that species, I am inclined to think them distinct. The plates are thick
and deep (PI. V, fig. 7 a, 4); the areolas are circular, with a complete circle of scrobicular
granules around them; the bosses are raised a little way above the margin of the areola,
and the summits are feebly crenulated; the tubercle is large, and supported on a short
stem; the miliary zone is wide and concave, and there are six or eight rows of coarse
granules filling up the same. The ambulacral areas are narrow, with two rows of
marginal granules, one granule being opposite each pair of holes; the poriferous zones
are narrow, the holes are round, and the septum has a tubercle developed on its surface ;
there are seventeen pairs of holes opposite one large tubercular plate. The spines,
associated with the plates in the same bed, are well preserved (Pl. V, fig. 7 d, ¢);
the acetabulum and head are small; the neck is long and smooth; and the stem is
covered with granules, which are arranged in lines that are not longitudinal, but slightly
waved. Most of the fragments appear to have been drifted; they are more or less
covered with a species of small serpula, which seems to have been abundant in the seas of
that period.

Afinities and differences——This species very much resembles Cidaris Beuchardiz, but
its tubercles are proportionately larger, and the areolas are smaller; the scrobicular circle
of granules is more defined, the miliary zone contains a greater number of granules,
and there is a granular space between some of the scrobicular circles which does not
exist in Cidaris Bouchardit.

Locality and Stratigraphical position —The plates and spines of this species have been
collected from the Bradford Clay, near the Tetbury-road Station of the Great Western
Railway, associated with R/ynchonella concinna, Sow., Terebratula cardium, Lamarck,
Terebratula digona, Sow., and other Bradford Clay forms.

4A

Ciparis FLoricgemMA, Phillips.

CIDARIS.

D. Species from the Coralline Oolite.

Pl. II, fig. 2 a, 6, ¢, d, e,f; Pl. VIII, fig. 4 a, 4, ¢, d.

‘“‘LaprpEs JUDAICI OF OXFORDSHIRE.” Plott, Natural History of Oxfordshire, pl. 6, figs.

8, 9, spines only, p. 125, 1677.

“RapioLus ECHINITH MAXIMI LATICLAVII.” Lhwydd (Luidius), Lithophylacii Brittanici

Ichnographia, editio Altera Oxonii, 1760, t. 12, fig. 1002, p. 49.

DIE NATURGESCHICHTE DER VERSTEINERUNGEN, Kwnorx II, i, t. 8, figs. 4, 5; t. £, vi, fig. 9,

CipaRites BLUMENBACHII.

CIDARIS FLORIGEMMA.

CIDARITES ELONGATUS.

— FLORIGEMMA.
Ges Berane
Ciparitrs BLUMENBACHII.

CipaRrites BLUMENBACHII.

CipARIS BLUMENBACHII.

= FLORIGEMMA.

1768.
‘© A GLOBOSE MAMMILLATED ECHINITE FROM OXFORDSHIRE.’

> Parkinson, Organic Remains,

pl. 1, fig. 9, and pl. 4, figs. 15 and 17, vol. iui, p. 13, 1811.

Goldfuss, Petrefacta Germanie, p. 117, t. 39, fig. 3 ¢, d, e
(aculei non testa), 1820.

Phillips, Geology of Yorkshire, pl. 3, figs. 12 and 13, p. 127,
1829.

De la Beche, Geological Manual, 3d edition, p. 535, 1833.

Roemer, Die Versteinerungen des Norddeutschen Oolithen-
Giberges, pl. 1, fig. 14, p. 27, 1836.

Desmoulins, Etudes sur les Echinides, p. 338, No. 31, 1837.

Agassiz, Prodromus Echinoderm., No. 31.

Id. Echinodermes Fossiles Suisse, part u, t. 20, figs. 5, 6
(non fig. 7), p. 56, 1840.

Id, Catalogus systematicus ectyporum Echinodermatum Fos-
silum, p. 10, 1840.

Lamarck, Histoire Naturelle des Animaux sans Vertébres,
2d edition, tome iii, p. 386, 1840.

Morris, Catalogue of British Fossils, p. 49, Ist edit., 1843.

Wright, Annals and Magazine of Natural History, 2d series,
vol. viii, p. 248.

Bronn, Lethzea Geognostica, 2d edition, p. 140, 1851.
Cotteau, Etudes sur les Echinides Fossiles du département
de l’Yonne, pl. 10, figs. 7, 8 (non fig. 6), p. 108, 1852.
Desor, Synopsis des Echinides Fossiles, t. 3, fig. 14, p. 5, 1854.

Morris, Catalogue of British Fossils, p. 74, 1854.
Woodward, Memoirs of the Geological Survey, Decade V,
Notes to Cidaris.

Test round, much inflated at the sides, and depressed at both poles ; ambulacral areas

narrow, elevated, and sinuous, with two marginal rows of granules set on basal eminences>
and in the widest part of the area, two other rows of very small granules, without basal
eminences, the middle rows disappear at both ends of the areas: inter-ambulacral areas
wide, with two rows of primary tubercles, from six to seven in each column; areolas rather
oblong, and surrounded by a prominent elevated scrobicular circle of well-spaced-out
granules, set on shield-like bases ; miliary zone wide, concave, and filled with several rows

ECHINODERMATA. 45

of small granules; mouth opening small, peristome pentagonal; apical disc opening large
and pentagonal; primary spines with large, thick, cylmdrical stems, ornamented with
longitudinal rows of prominent, forward-directed granules; secondary spines short and
spatulate, covered with fine longitudinal lines ; tertiary spines small, conical, or oval shaped.

Dimensions.—a. Large specimen: Equatorial diameter, two inches and four tenths of
an inch ; height, one inch and seven twentieths of
an inch.

B. Large specimen: Equatorial diameter, two inches and two tenths of
an inch; height, one inch and four tenths of an
inch. :

c. Usual-sized specimen: Hquatorial diameter, one inch and four tenths
of an inch; height, one inch and four tenths of
an inch.

Description —tThis noble urchin was very abundant in the Corallian Seas of Hurope,
and its test and spines form characteristic fossils of this stage of the Jurassic group. Much
confusion regarding this species has been caused by Goldfuss having figured, along with
the test of Cidaris Blumenbachii, Minster, the spines of three or four other species of urchins,
and especially in having erroneously described the spines of Cidaris florigemma as
belongmg to the test of Cidaris Blumenbachii. 1 am indebted to my friend
Mr. S. P. Woodward for having called my attention to this subject, as he has always
maintained that Cidaris florigemma, Phil., was distinct from Cidaris Blumenbachu, Golde.
Having been fortunate in finding the slab, figured in Pl. II, fig. 2 a, containing a small
Cidaris florigemma with spines attached, I had direct evidence that the spines figured by
Goldfuss as those of Cidaris Blumenbachi in reality belonged to the Wiltshire urchin.
The next point to be ascertained was, whether the test figured by Goldfuss was different
from the test of this species. A critical examination and comparison of good type speci-
mens of Cidaris Blumenbachii, one-in the collection of the British Museum, and another
kindly sent me by Dr. Fraas, of Stuttgard, with the specimen figured in Pl. I, fig. 2 4, ¢,
has proved that they are very distinct from each other.

Plott, in 1677, figured the spines of this urchin under the name of Lapides Judaict.
He says—‘“ We find them here (Oxfordshire) of different sizes, from about two inches
in length and an inch and a half in circuit, downwards to an inch and Jess in length and
not much above half an inch round. Most of them have a pedicle from which they seem
to have had their growth, and are ridged and channelled the whole length of the stone,
the ridges being parted with small knots set in quincunx order. As to their texture, I
find it to be very curious, made up of lamelle or little thin plates, not unlike the stone
Selenites ; only these are opaque, and the whole bulk of the stone mdeed much different.
The plates, as in the Selenites, seem to be made up of strings, which in most of them run

A6 CIDARIS.

three, but in some but two ways: according to the running of these strings the stones
will easily cleave, but generally some one way rather than any other, which most com-
monly is agreeable to the helical running of the ridges of knots or furrows between them,
yet always obliquely to the axis of the stone, as is perfectly shown, tab. vi, fig. 9, which
represents the stone broken three several ways.”’*

Lhwydd, in 1690, figured spines of the same species from the Coral Rag of Oxford-
shire. Parkinson, in his ‘Organic Remains of a Former World,’ gave a beautiful figure
of the test (Pl. I, fig. 9), which, it is but just to state, has been entirely overlooked, the
references to his work having been made only to the figures of the spines (Pl. IV, figs.
15, 17); the first good figure of the test of this species therefore is, in reality, that of
Parkinson’s. In the ‘ Petrefacta Germanie,’ Goldfuss gave good figures of the spmes
which he stated appertained to the test of Crdaris Blumenbachi ; and subsequent paleeon-
tologists, believing his statement, have nearly all followed his error. In the ‘ Description
des Echinodermes Fossiles de la Suisse,’ M. Agassiz has figured the spines of Czdaris
florigemma with the test of Cidaris Blumenbachii ; this is shown in the figure by the small-
ness of the granules of the scrobicular circle, in the smallness of the tubercles, and the
depth of the crenulations on the summits of the bosses, a group of characters which
belong to Cidaris Blumenbachii. In the ‘ Geology of Yorkshire,’ Professor John Phillips
figured a test and spine of this species, under the name Crdaris florigemma, from a Wilt-
shire specimen now in the Museum of the Yorkshire Philosophical Institution ; the correct-
ness of the determination then made has been proved by the tedious investigation which
was necessary to clear away the existing confusion relative to this species. M. Desor, in
his ‘Synopsis des Kchinides Fossiles,’ restricts the name Cidaris Blumenbachii to the spies,
“aculei non testa,” figured by Goldfuss; but I cannot agree with my friend in this con-
clusion, because Miinster gave the name to ¢he fest, about which there can be no mistake.
Goldfuss’s error consisted in describing and figuring spines as belonging to this test which
appertained to another species ; therefore I say “testa non aculei” in the synonym: as the
test is the body of the animal, and the spines are merely appendages of the same, it follows
that the name given by an author to a species must in every case relate to the major, and
not to the minor part described. Mimster’s name, therefore, must still be given to the
German form ; which, as far as is at present known, has not yet been found in England.
M. Desor observes: ‘‘J’ai été fort longtemps dans le doubte sur les limites de cette
espece, par la raison que les radioles et le test que Goldfuss a réunis, n’appartiennent pas
au méme oursin. C’est tout récemment que la découverte de quelques échantillons avec
leurs radioles attachés au test, m’a permis de rectifier l’erreur dans laquelle }’étais tombé
avec d'autres paléontologistes. Le test figuré par Goldfuss n’a rien de commun avec les
radioles qu il lui attribue; il appartient & une autre espéce décrite ulterieurement par M.
Agassiz sous le nom de C. Parandiert. Or, comme les radioles sont bien plus abondants

* Plott’s * Natural History of Oxfordshire,’ p. 120.

ECHINODERMATA. AT

que les tests et qu’ils sont connus de tous les paléontologistes c’est a eux, et partant au test
décrit ci-dessus, que je crois devoir conserver le nom primitif de Cidaris Blumenbachii.” *

The test of Cidaris florigemma is round, and much inflated at the sides ; it is mode-
rately depressed at both poles, but is most so on the upper surface; the ambulacral areas
are narrow, and nearly of a uniform breadth throughout; they are very sinuous and _pro-
minent, and are furnished with two rows of granules on the margins of the areas; between
these, for about the length of two of the large tubercular plates, there are two rows of very
small granules internal to the marginal ones (PI. I, fig. 2 7); the marginal granules are
raised on small basal eminences, but the mternal granules are not ; the six or eight marginal
pairs nearest the peristome are very much larger than those in the middle and upper parts
of the areas: the poriferous zones are of moderate width; the pores forming a pair are
separated from each other by a septum equal in width to the diameter of a pore (fig. 2 9) ;
there are nineteen or twenty pairs of pores opposite each of the large equatorial tubercular
plates; the zones are rather deep, from the prominence of the ambulacral areas in the
middle, and that of the scrobicular circles external to them.

The inter-ambulacral areas are nearly five times the width of the ambulacral areas and
poriferous zones; the plates of the tubercular columns are deep, there being only from six
to seven plates in each column; the areolas are large and circular, especially above, but
they incline towards an oval from below; their margins are surrounded by a prominent
scrobicular circle of fifteen or sixteen well-spaced-out granules (fig. 2 g), each of which is
raised on an oval, shield-like base. In consequence of the size of the areolas in the upper
part of the areas, the scrobicular circles of the two uppermost pairs closely approximate ;
but from this point to the peristome there is a considerable inter-tubercular space, which
is filled up with miliary granules of different sizes; those nearest the areolas are raised
on small basal elevations, which alternate with those of the scrobicular circle, and the
rows internal to them diminish in size as they approach the median sutural line, where
they become quite miliary: the mammillary bosses rise from a wide base (fig. 2 g); the
three or four lower pairs have smooth summits, and the two or three upper pairs only are
crenulated ; the crenulations, however, are by no means either deeply sculptured, or very
persistent in different specimens; the tubercles are large, and are raised on a slightly
contracted neck; the perforation in the hemispherical head has the form of an oblong slit,
which passes through the head, and extends to the summit of the boss.

The mouth opening is large, and the peristome has a pentagonal form (fig. 2 4). In
specimen B, it measures nine tenths of an inch in diameter, that of the equatorial diameter
being two! inches and two tenths; the primary tubercles in the vicinity of the peristome
are large and well developed, although smaller than those on the sides and upper sur-
face of the test; the minute tubercles at the base of the ambulacral areas are only a little
larger than the marginal granules of these areas.

* *Synopsis des Echinides Fossiles,’ p. 5.

48 CIDARIS.

The apical disc is absent in all the specimens I have examined. It was of considerable
size; the diameter of the opening in specimen B being 4+<ths of an inch.

The spines are of three kinds, the primary, the secondary, and the tertiary. (PI. II,
fig. 2d, e,7.) The primary spines or radioles are very elegant bodies, and as they are often
preserved in the Corallian stage, when the test to which they belonged is not discovered,
a knowledge of them is of stratigraphical importance to the student of the Jurassic rocks.
The concave articulating cavity has a deep pit im its centre (fig. 2 e) for the insertion of a
ligament, and the rim of this acetabulum is surrounded with a circle of moniliform crenu-
lations ; the head is small, and is surrounded by a narrow ring, nearly smooth, and covered
only with a microscopic milling of longitudinal lines; the ring is midway between the rim
of the acetabulum and the poimt where the head articulates with the neck (fig. 2 e); the
neck is short, and is covered with fine longitudinal lines ; it soon expands to form the body
of the spine, the thickest part of which is just beyond the neck, from whence the stem
gradually tapers to the apex, which is always more or less truncated (fig. 2 d); the stem
is covered with small granulations, very uniform in size, and regularly disposed in longi-
tudinal rows, forming from twenty to thirty lines of tubercles on the body of each spine,
the number of the rows varying in different spines; the tubercles of the adjoming rows
alternate, so as to produce a quincuncial arrangement; and the tubercles of each series are
connected together by a calcareous filament which passes from one tubercle to another; the
tubercles are all inclined towards the apex of the spine, and many of them terminate in
short, prickly processes, which have their points directed forwards; the surface of the
spine between the rows of granules is covered with numerous longitudinal lines: at the
summit of the spines the granules coalesce, formmg so many plates, which expand, and
produce a radiated or star-like disc at the truncated extremity thereof. Some of the spines
attain the length of two inches and three quarters. ‘The secondary and tertiary spines
are short and spatulate (fig. 2,7), and their surface is covered with fine longitudinal lines.

Afinities and differences —tIn the form and structure of the test in general, Cidaris
florigemma resembles Cidaris Blumenbachii, marginata, coronata, and monilifera, but it
is distinguished from all these forms by its greater height, and a consequent increase in
the number of plates in the tubercular columns; Cidaris marginata, coronata, and
monilifera having five plates in each column, whilst Cidaris florigemma has from six to
seven. In the plates on the upper part of the test of these species, the miliary zone is
much wider, and the circles of areolar granules are likewise separated by many rows of
miliary granules, which are altogether wanting in Cidaris florigenma. The ambulacral
areas in Cidaris marginata, coronata, and monilifera have four distinct rows of small,
nearly equal-sized granules, whilst in Cidaris florigemma the two marginal rows alone are
well developed throughout.

Cidaris florigemma is distinguished from Cidaris Fowleri by the narrowness of its
ambulacral areas, and by the size and prominence of the marginal granules; the

ECHINODERMATA. 49

poriferous zones are likewise very much narrower, and the pores are smaller and set closer
together; the inter-ambulacral areas are wider, whilst the miliary zone is narrower ;
the scrobicular circles are likewise much more prominent, and have larger granules,
raised on distinct eminences; the smooth summits of the mammillary bosses of the
lower tubercles, and the faint crenulations on those of the upper ones, form a striking
contrast to the broad, deeply crenulated summits of the mammillary bosses in Cidarzs
Fowler.

The same group of characters which serve to distinguish Crdaris florigemma from
Cidaris Fowlert form the diagnosis between it and Cidaris Orbignyana.

Cidaris florigemma resembles Cidaris Smithii, Wright, with which it is occasionally
associated in the same rock in Wiltshire and Yorkshire, in the general form and height of
the test, but it is distinguished from this much rarer species by having fewer tubercles in the
inter-ambulacral areas, and much more prominent scrobicular circles around them; Cidaris
Smithii having ten primary tubercles in each column, and the granules of the scrobicular
circles not being much larger than those fillmg the milary zone; the ambulacral areas
are likewise narrower, and the poriferous avenues are narrower and deeper; the spines,
likewise, are longer, narrower, and differently sculptured.

The primary spines of Cidaris florigemma most nearly resemble those of Cidaris coronata,
but their length, and the regularity of their rows of granules, serve to distinguish them
from those of that species. The only other species of Cidaris with which it is necessary to
compare them, is that of Czdaris Smathi, which sometimes occurs with Cidaris florigemma
in the same rock in England. Although the tests of these two species resemble each other
when of the same size, still the spines show that they belong to two distinct groups of
urchins, the stems of Cidaris florigemma being thick and massive, whilst those of Cidaris
Smith are long and slender, tapering very gradually from neck to point; the surface is
covered with elevated longitudinal ridges, covered with sharp, forward-directed prickles ;
these spines are sometimes nearly twice the length of those of Crdaris florigemma. (PI. V,
fig. 5.) The test of Cidaris Blumenbachii has the areolas deeply excavated; the bosses
not very prominent, the summits all sharply crenulated, and the tubercles small; the
granules forming the scrobicular circle are not larger than those of the small granulation
filling the miliary zone. These characters are so completely diagnostic, that it is impos-
sible to mistake the true German form for Cidaris florigemma, when the two urchins are
placed side by side for comparison. If to these characters of the test, however, are added
those obtained from the spines, we learn how entirely distinct Cidaris Blumenbachii is
from Cidaris florigemma.

Locality and Stratigraphical position.—Cidaris florigemma is found in fine preserva-
tion in the Coralline Oolite of Wiltshire, Berkshire, Oxfordshire, Yorkshire, and Dorsetshire.
The specimens figured in Pl. II were collected near Calne, in Wilts; and I have seen
a beautiful specimen found in that formation at Hildenly, near Malton, Yorkshire.

7

50 CIDARIS.

Judging from the spines figured by Goldfuss, Agassiz, Roemer, and Cotteau, this
species must have had a wide Huropean area of distribution, as its test or spines have been
collected in the Coral Rag of different parts of Germany, Switzerland, and France.

History.—The history of this species has been given with so much detail in the
introductory remarks, that it is unnecessary to reproduce the facts under this section,

Ciparis Smita, Wright, nov. sp. PI. I, fig. 1 a, 6, c, d,e; Pl. V, fig. 5 a, 6, ¢, d, e.

Test large, much inflated at the sides, and depressed at the poles ; ambulacral areas
flat, with two marginal rows of small granules, and two inner rows of microscopic granu-
lations ; poriferous zones wide, the pores separated by very thick septa; inter-ambulacral
areas with ten primary tubercles in each row; areolas oval, and deeply sunk ; scrobicular
granules not larger than the miliary granules; miliary zone wide and concave, and filled
with six or eight rows of nearly equal-sized miliary granulations; mouth opening wide,
peristome pentagonal, Jaws and teeth large and powerful; primary spines long, slender,
and tapering; surface of the stem with thick longitudinal ridges, from which stout
forward-directed processes proceed.

Dimensions.—Height, one inch and eight tenths of an inch; transverse diameter, two
inches and three fourths of an inch.

Description.—This noble urchin is a much rarer form than the preceding species, with
which, however, it is sometimes associated in the same beds of the Coralline Oolite in
Wiltshire and Yorkshire. As a distinct species, it has hitherto escaped the notice of
palzeontologists.

The test is large, much inflated at the sides (Pl. IL, fig. 1] 4), and depressed at
both poles; the ambulacral areas are slightly elevated, of moderate width, and gently
undulated; they are widest at the equator, and diminish above and below; they have
two marginal rows of small granules, which are alternately larger and smaller (fig. 1 ¢) ;
sometimes two of the smaller granules are interposed between every two of the larger
ones ; within these marginal rows are two rows of close-set, equal-sized, microscopic
granules, which disappear at the upper and lower parts of the areas.

The poriferous zones are very superficial, and are nearly as wide as the areas; the
pores are separated by thick septa, and the pairs of pores are directed obliquely upwards ;
the holes of the inner row are round, whilst those of the outer row are oblong or pyriform ;
the septa are slightly scooped out on their margins above and below, so that each pair of
pores, with its intervening partition, somewhat resembles the frame of a pair of spectacles,

ECHINODERMATA. 51

with a straight bridge (fig. 1 c); the bevelled margins of the septa produce an appearance
like a third row of blind holes in the centre of the zone; there are from thirteen to fourteen
pairs of pores opposite one of the large tubercular plates.

The inter-ambulacral areas have a greater number of tubercular plates than is found in
any other Oolitic species; im each column there are ten plates, the primary tubercles of
which are proportionately small; the areolas are oblong, and are rather deeply sunk,
with sharp, prominent margins; the granules forming the scrobicular circle are not larger
than those filling the miliary zone; the bosses are not very prominent, and are only a
little higher than the rim of the areolas; their summits are flat, and sculptured with
fourteen deep crenulations (fig. 1 d) ; the tubercles are small in proportion to the dimen-
sions of the test, and are very uniform in size throughout the area; the areolas on the
upper part of the areas are nearly circular, those at the under part are oblong; only the
upper five areolas have complete circles of granules round their margins ; and the three or
four lower areolas are separated by a transverse ridge of the test, on which no granules
are developed.

The miliary zone is broad and concave, and is filled with eight or nine rows of small
granules, set on eminences, around the bases of which circles of microscopic granules are
very regularly disposed; between the poriferous zone and the adjoming row of tubercles,
there is a miliary zone filled with three or four rows of granules.

The mouth opening is large (fig. 1 a); the peristome is pentagonal, but its figure
cannot be accurately described, as several of the plates are fractured; the lantern is large,
and was composed of five powerful jaws, which remain with their teeth iv stu. In the
fine specimen communicated by my friend, the Rev. P. B. Brodie, and figured in fig. 1 a,
each jaw consists of a broad central portion and two lateral carinz ; the long, curved,
conical, triangular teeth are bevelled into a chisel-like form on the imner surface, and
project five twentieths of an inch beyond the alveoli.

The spines are long, slender, and tapering (Pl. IL, fig. 1 e, and PI. V, fig. 5 a, 6, c,d, e); ,
the head is short, with a slightly prominent milled ring (fig. 5 ¢); the acetabulum is
sharply crenulated (fig. 5 d); the neck is marked with fine longitudinal lines (fig. 5 ¢) ;
the stem is round or oval (fig. 5 e), and is covered with eight or nine prominent longitudi-
nal ridges, which have short, stout, oblique, forward-directed prickles developed from their
surface (fig. 5 a, ¢); a fragment of the stem (fig. 5 @) is nearly three inches in length.

Affinities and differences.—This species very much resembles Cidaris Blumenbachii,
Miinster, in the general structure of the test, but it is distinguished from that species by
the followmg characters: In Cidaris Blumenbachii the poriferous zones are narrow, and
the pores are all round ; the inter-ambulacra have only from six to seven tubercles in each
row, and the areolas are sunk and circular. In Cidaris Smithw the poriferous zones are
wide; of each pair of pores, the one is round, and the other is oval; the inter-ambulacra
have ten tubercles in each row, and the areolas of the inferior tubercles are oval. Both

52 ~). CIDARIS.

forms have wide miliary zones, but those of Cidaris Smithii are the widest; the granules
of the scrobicular circle in both are not larger than those of the miliary zone, and both
have deeply sunk areolas.

A comparison of figs. 1 and 2, in Pl. II, will show in what Cidaris Smithii differs
from Cidaris florigemma. 'The latter has circular areolas, with a well-developed scrobicular
circle of large granules (fig. 2 g); narrow poriferous zones; large tubercles, with smooth
bosses, and seven tubercles in each row. The spines of Crdaris florigemma (PI. IL, fig. 2 d)
have a thick, clavate stem, with longitudinal rows of moniliform murications; whilst
those of Cidaris Smithit are long, slender, and tapering, with longitudinal elevations
carrying forward-directed processes.

Cidaris Smithii resembles Cidaris maxima, Minster, in the general structure of both
areas, but the former has more tubercles in each row in the inter-ambulacral areas
than the latter species. The spines of Cidaris Smithiz have a more regular arrangement
of the longitudinal elevations and processes thereon ; the stem likewise tapers gently from
the neck to the apex, and wants the central swelling and irregular forward-directed
prickles which characterise the spines of Cidaris maxima.

Locality and Stratigraphical position.—This species was collected long ago, from the
Coral Rag of Hillmarton, Wiltshire, by the late Dr. William Smith, the father of English
paleontology. ‘The original specimens are now in the British Museum. Mr. Lowe col-
lected it from the Coral Rag of Calne, Wilts. Dr. Murray, of Scarborough, found a
beautiful specimen in the Coralline Oolite of Ayton, near Scarborough, which is now im
his cabinet. The Rev. W. F. Witts collected some plates and spines in the Upper Calca-
reous Grit near Scarborough Castle. Mr. William Buy has found two or three very perfect
specimens in the Coral Rag near Calne; and Mr. Gibbs has collected plates and spines
from the same formation in other localities in Wiltshire.

This species, therefore, characterises the Coralline Oolites of England, and belongs to
the same horizon as Cidaris florigemma, Diadema pseudo-diadema, Diadema versipora,
with which it is associated in the same rock.

History.—This species has, by some, been mistaken for Crdaris florigemma ; and, by
others, has been considered to be the true Cidaris Blumenbachit. The zootomical details
into which I have entered show that it is very distinct from both.

It is now figured and described for the first time. I dedicate this fine species to the
memory of our distinguished countryman, Dr. William Smith, whose accurate observations,
large views, and many researches conducted in a true philosophical spirit, led to the dis-
covery of that great stratigraphical law, that each of the different strata of the earth’s crust
contains its own specific forms of organic life.

ECHINODERMATA. 53

E. Species from the Kimmeridge Clay.

[Spines of which the test is unknown. |
Crparis spinosa, Agassiz. Pl. XII, fig. 4.

Crparts spInosA. Agassiz, Echinodermes Fossiles de la Suisse, part ii, p. 71, pl. 21, fig. a.
— — Desor, Synopsis des Echinides Fossiles, p. 26, t. 3, fig. 2.
— — Morris, Catalogue of British Fossils, 2d edit., p. 75.

The principal character of this species consists in the prominent thorny processes
which project from the surface of its stem, which is round and slender, and is likewise
finely marked with longitudinal lines ; the neck is short. It is exceedingly difficult to deter-
mine from a single spine, without comparing it with the type, whether that which is figured
is identical with the Cidaris spinosa, Agass. It certainly comes nearest to that form with
which it is provisionally placed. It was collected from the Kimmeridge Clay of Aylesbury.

Crparis Botonrensis, Wright. Pl. XII, fig. 5.

Spine long, nearly two inches in length; acetabulum deeply crenulated ; ring promi-
nent, acutely carmated; neck long, slender, smooth ; stem flattened, covered with finely
granulated longitudinal ridges, which have prominent, thorn-like, forward-directed pro-
cesses, developed at irregular intervals on the stem, which is flat and oar-like at its distal
extremity. On this blade-like termination there are sometimes prominent, longitudinal
carine, formed by the excessive development of the terminal granulated lines.

Affinities and differences.—This spine resembles that of Cidaris Ordignyana in its
general characters; but it has a longer neck, a more prominent and acutely carinated ring,
and the stem is likewise furnished with stouter thorn-like processes; in the flattened
condition of the distal extremity it resembles that species. It is altogether a stronger and
larger spine than that referred to Codaris spinosa, and its long, smooth neck serves to
distinguish it from that species.

Locality and Stratigraphical position —Collected by the late Hugh Strickland, Hsq.,
from the Kimmeridge Clay, Dorset. ‘The same species* has been foumd by M. Bouchard
Chantereaux, who kindly sent me a series of spines, from the Kimmeridge Clay near
Boulogne-sur-Mer, where it is very rare.

* ‘Notes on Foreign Jurassic Species,’ page 63.

54 RABDOCIDARIS.

Genus 2—RABDOCIDARIS,* Desor.

This genus was formed by M. Desor to include all the large inflated Cidarites, which
are often as high as they are in transverse diameter; their poriferous zones are likewise
wider than m the genus Cidaris, the pores forming a pair are placed wider apart, and con-
nected by a small horizontal sulcus. The ambulacra are straight, or very little flexed.
The tubercles are large, and always strongly crenulated, and, in the fossil species at least,
proportionately more numerous than in the true Cidaris. The areolas are large, and often
elliptical; the miliary zones are wide. ‘The spines are large, and have a long and much
developed stem.

The species at present referred to this genus are Oolitic and Neocomian.—Desor.

A. Species from the Lnas.

Raspociparis Moraupina, Cotteau. Pl. V, fig. 3.

CIDARIS MORALDINA. Cotteau, Etudes sur les Echinides Fossiles, p. 33, pl. 1, figs.
1—3.
RaBDOCIDARIS MORALDINA. Desor, Synopsis des Echinides Fossiles, p. 42.

Test large, form unknown; inter-ambulacral plates large; areola oval, occupying a
considerable portion of the plate; mammillary boss with a broad base, not much elevated,
summit deeply crenulated ; tubercle proportionately small, with a large perforation.

The only specimen I have seen of this urchin is the one figured in Pl. V. It was
collected by Mr. Moore from the Marlstone of Somerset. M. Cotteau, who first described
the species, founded it upon the imprint of a fragment. Judging from the size of the
single inter-ambulacral plate, it must have been a very large Cidarite; the areolas are wide _
and oval, and, from the space they occupy, they must have been confluent above and
below, and surrounded only by incomplete scrobicular circles; the miliary zone was flat
and wide. This species has some affinities with Cidaris maxima, Mister ; but it is dis-
tinguished from it by many marked characters: the inter-ambulacral plate is one half
larger ; the areola is not excavated out of the substance of the plate, as in Cidaris maxima,
but is level with the surface, and the mammillary boss forms a much larger eminence
thereon ; the summit is likewise broader and more deeply crenulated.

* paPdoros, striated, canaliculated.

ECHINODERMATA. 55

Locality and Stratigraphical position This fragment was collected from the Marl-
stone near Ilminster; the specimen figured is all that has ever been found in that
locality ; the bed in which it was discovered is characterised by the presence of Ammonites
margaritatus, Montfort. It is interesting to find that M. Cotteau’s specimen was col-
lected “ dans les couches a Gryphea Cymbium de Vassy pres Avallon,”’ where it is very
rare: this Gryphea bed corresponds very nearly with the horizon of the Middle Lias in
Somersetshire, where the fragment before me was found.

B. Species from the Great Oolite.

Raspocrparis MAXIMA, Minster. Pl. XII, fig. 6; Pl. A, fig. 16.

CIDARITES MAXIMUS. Goldfuss, Petrefact. Germanie, p, 16, t. 39, fig. 1 a, 6.
KNOTTED SPINE oF CrpaRis. Phillips, Geology of Yorkshire, t. 9, fig. 5.

CIDARIS MAXIMA. Morris, Catalogue of British Fossils, 2d edit., p. 74.
RABDOCIDARIS MAXIMA. Desor, Synopsis des Echinides Fossiles, p. 39.

The large spine, figured by Professor Phillips, from the Grey Limestone (Great Oolite)
of Gristhorpe Bay, Yorkshire, (two of which I collected last summer,) I have identified
with a spine kindly sent me by Dr. Oppel, of Stuttgart, from the Inferior Oolite of Neuffen,
Wiirttemberg, as typical of Miinster’s species. A very large and fine specimen of this Great
Oolite spine is figured in Pl. A, fig. 16; it measures five inches and a quarter in length.
The head is large; the rim of the acetabulum is coarsely and deeply crenulated ; the neck
is short and smooth; the stem is long and sub-fusiform, nearly five inches im length, it
gradually swells out in some specimens towards the middle, and tapers very little towards
the distal extremity; the surface is covered with short, stout, thorn-like prickles, with
their points slightly directed forwards, which are irregularly developed, at considerable
distances apart; they do not form straight lines, but stud the surface in a somewhat
spiral order.

None of the plates belonging to this large spine have yet been found in Yorkshire,
nor in the Great Oolite of the West of England.

56 DIPLOCIDARIS.

Genus 3—DIPLOCIDARIS,* Desor.

The genus Diplocidaris is formed of large urchins, which have all the characters of
the true Cidaris, but differ from them only in one particular, in having the pores in
the zones so arranged as to form double rows, or double oblique pairs, every third pair
being vertically above the third pair below them; whereas in the genus Cidaris the pores
are strictly unigeminal throughout. This important modification in the structure of the
poriferous zones has corresponding relations with the number and disposition of the
tubular suckers, and probably with the function of respiration. The ambulacral areas are
narrow, straight, and flexed, with two rows of small marginal granules ; the inter-ambulacral
areas are wide; the areolas are round or elliptical, and the bosses have deeply crenulated
summits ; the tubercles are of moderate size; the miliary zones are very wide, and the
surface of the plates is covered with large well-defined granules, set at some distance from
each other.

“The spines are short, massive, and cylindrical ; their surface is covered with granules,
or pustules, instead of spines as in Radbdocidaris.”—Desor.

All the species known have been found in the Oolitic rocks.

A. Species from the Upper [nas ?
Dietociparis Dzsori, Wright, nov. sp. Pl. VIII, fig. 5.

Test large, form unknown; ambulacral areas narrow and slightly flexed, with two
rows of small marginal granules; poriferous zones follow the flexures of the area; the pores
round, and contiguous, the septum as thick as the diameter of the pore, with a prominent
tubercle on its surface ; every two pairs of pores are set obliquely to each other, so that
the pores of every third pair stand vertically over each other ; inter-ambulacral plates large,
rhomboidal, as deep as they are broad; areola large, circular; scrobicular circle complete,
abutting against the poriferous zones; granules of the circle of the same size as those
covering the rest of the plate; areola shallow, boss not prominent, tubercle small; miliary
zone wide, with four or six rows of well-spaced-out granules.

The fragment which I have figured was kindly communicated by my friend,
Mr. S. P. Woodward; it was collected near Yeovil, from a rock supposed to be Inferior
Oolite.

It is very interesting to find this fragment of a Diplocidaris so far down in the Oolitic
series, as the specimens of this genus hitherto discovered have all been found in the Coral

* From dios, double.

ECHINODERMATA. 57

Rag of Nattheim, Besancon, Chatel-Censoir, and Druyes (Yonne); the only exception to
this being a spine (PI. I, fig. 5) found by me in the Pea Grit, Inferior Oolite, of Crickley
Hill, and placed by M. Desor in this genus.

The inter-ambulacral plate is large, as deep as it is wide, and must have formed
part of a very large test; the areola is rather more than two thirds of the width of the
plate, it is circular, and is placed so near the poriferous zone that its scrobicular circle
abuts against the pores. ‘The areola is smooth, superficial, and not excavated ; the boss
forms an inconsiderable prominence in the centre, and has a broad summit, which was
crenulated, although the remains of the markings are vow nearly effaced. The tubercle is
small in proportion to the size of the plate; the miliary zone must have been very wide,
and filled with four or six rows of large granules, which stand at distinct imtervals apart.
The scrobicular circle is complete ; the granules forming it are set upon an elevated rim of
the areola, but they are not larger than the other granules covering the surface of the
plates.

The ambulacral areas are very narrow and flexuous, having two rows of small granules
on their margins; the poriferous zones follow the windings of the area, which are more
flexuous in this species than in the German Coral Rag forms, in consequence of the
proximity of the scrobicular circle to the zones themselves ; in fact, the absence of flexures
in Diplocidaris gigantea led M. Desor to state that the ambulacra were straight in this
genus; whereas they are both straight and flexed, in proportion as the tubercles occupy
the middle or the zonal sides of the plates.

The poriferous zones are narrow; the pores are round and contiguous, separated by
septa, about as thick as the diameter of the holes; on the surface of the septa the test is
elevated, and forms small, blunt granules; the pores are not, strictly speaking, bigeminal,
but form an irregular series, every pair being more or less oblique to the pair above them

and below them ; they may be described as forming double oblique pairs, thus, %: so that

every third pair of holes stand vertically above a third pair below them, a form of arrange-
ment very different from that prevailing in the genus Cidaris, in which the pores are
strictly unigeminal throughout the entire zones.

Affinities and differences—Diplocidaris Desori differs from Diplocidaris gigantea in
having deeper rhomboidal plates; and the areolas and tubercles are placed closer to the
poriferous zones; the ambulacral areas are likewise narrower; the pores form double
oblique pairs in the zones, instead of making two distinct series as in Diplocidaris gigantea.

Locality and Stratigraphical position —This fragment was discovered near Yeovil,
in a rock supposed to be Inferior Oolite, but which probably may be Upper Lias. It
is impossible to say anything upon this point, unless the Ammonites with which it was
associated were before me, inasmuch as the stratigraphical line between the Upper Lias

8

58 DIPLOCIDARIS.

and Inferior Oolite of Somersetshire has not yet been accurately defined; and indeed it
is only by paleontological characters that the one rock can be distinguished from the
other. Lithologically, the rock in which Diplocidaris Desori is imbedded reminds me more
of the Upper Lias of that region than of the Inferior Oolite.

I dedicate this species to my friend M. Desor, who has established the genus to
which this urchin is referred.

B. Species from the Inferior Oolite. ~

Dirtociparis Wricuti, Desor. Pl. I, fig. 5 a, 6.

[ Species of which the test is unknown. |

DipLocipaRis Wrieutit. Desor, Synopsis des Echinides Fossiles, p. 45, pl. 7, fig. 24.

The spine on which M. Desor established this species was figured in my ‘ Memoir on
the Cidaridee of the Oolites,’ and was, by mistake, drawn with the spines since ascertained
to belong to Cidaris Fowleri, The articulating head is small, the rim of the acetabulum
deeply crenulated, and the cup largely perforated; the rimg is carinated and finely
milled; one half of the neck is covered with longitudinal lines, and the other half is
smooth (PI. I, fig. 5 4); the stem is round, and gradually swells out towards the middle,
where it is fractured ; it is covered with small pustules, which are rather irregularly dis-
posed on the surface, and not arranged in lines. M. Desor says it resembles the spines
of Diplocidaris gigantea, but the stem is more swollen out in the middle than in that
Corallian species.

Locality and Stratigraphical position—I have fragments of three spines, which
were all collected in the Pea Grit, Inferior Oolite, at Crickley Hill, along with the test and
spines of Cidaris Fowleri.

NOTES

On some Fornien Jurassic spucius oF CIDARIDAN nzarty ALLIED To BritisH Forms,

BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITEs.

Genus—CIDARIS.

A. Species from the Lnas.
Ciparis AMALTHEI. Quenstedt, Petrefactenkunde, p. 574, t. 48, figs. 23—30.

The inter-ambulacral plates only are known; they attain a large size, nearly an inch
in breadth ; the tubercles are not so large in proportion, but they are deeply crenulated,
and have a large perforation in their summit ; areolas elliptical, large, distinct ; scrobicular
granules not larger than those fillmg the miliary zone. Spines long, slender; stem with
small, forward-directed prickles; head and acetabulum large; rim deeply crenulated ;
ring prominent ; neck partially covered with fine longitudinal lines.

Formation.—Lias, Donau-Mainkanal bei Dorlbach.

Collections—Museums of Bonn, Stuttgart; Professor Quenstedt. Specimens in my
Cabinet sent by Dr. Fraas.

B. Species from the Inferior Oolite.
Ciparis Lorieru, Wright, nov. sp., 1855.

Test high, one inch and two tenths, transverse diameter two inches, inclining to a
pyriform figure, narrow towards the base, and broad and flat at the upper surface; ambu-
lacra flat, with four rows of granules; poriferous zones as wide as the area, pores round,
separated by thick septa; inter-ambulacra with seven or eight plates in each column ;
areolas wide, superficial, with sharply defined margins, surrounded by small granules, of
the same size as those filling the miliary zone, which is narrow, and shows the centro-
sutural zigzag line well defined; bosses prominent, with broad, deeply crenulated summits;
tubercles deeply and largely perforated, gradually increasing in size from the peristome to
the coronal plates; disc opening small and circular.

60 FOREIGN OOLITIC CIDARIDA.

Formation.—Collected by M. De Loriere from the étage Bajocien, département de
Sarthe.

Collection.—My Cabinet.

This species comes very near to Cidaris Fowler: ; but it is distinguished from that
species by its pyriform figure, the circle of minute scrobicular granules, the wide areolas,
broad and deeply crenulated bossal summits, and wide and deep perforations in the
tubercles. These characters closely resemble those of Cidaris confluens, with which it has
many affinities.

Sent me most kindly by M. De Loriere, to whom I dedicate this fine new species.

C. Species from the Coral Rag.

Ciparis BuumunBacai1. Minst., in Goldf., Petrefacten, p. 117, t. 39, fig. 3 a, 6 (testa
non aculei).

Agassiz, Echinodermes Suisses, part il, p. 57, t. 20, figs. 2—6.

Cotteau, Etudes sur les Hchinides Fossiles, p. 108, t. 10, fig. 6?

Test inflated, depressed at both poles; ambulacra narrow and flexuous, with two rows
of small, very close-set granules ; poriferous zones narrow ; pores small, round, contiguous,
from 20 to 22 pores opposite one of the largest tubercular plates; areolas large, nearly
circular, deeply excavated, six to seven in each row, with a prominent margin; boss small,
summit broad, deeply crenulated; tubercle small and prominent; scrobicular circles complete,
margins touching, granules scarcely larger than those filling the wide miliary zones. Spines
not known, those referred to this species I have proved to belong to Cidaris florigemma.

Formation.—Coral Rag.

Localities —Besancon, Chatel-Censoir, et Druyes, Yonne; Saint-Mihiel, Vaches-Noires.
Corallien blanc de Hoggerwald, Canton de Soleure.
Jura superieur, Jurakalkes bei Thurnau und Muggendorf, Bavaria.
Formation «, Quenst., Sigmaringen.

Collections.—British Museum; very rare in English Collections; in almost all the
Foreign Collections ; my Cabinet.

Ciparis Paranpigri. Agassiz, Echinodermes Foss. Suisse, ii, p. 58, t. 20, fig. 1.

Test inflated ; ambulacra narrow, with two rows of granules at the base, and some-
times two other intermediate rows—four rows in the middle; the areolas, bosses, and
tubercles similar to the preceding species, of which it appears to be only a variety.

FOREIGN OOLITIC CIDARID A. 61

The spies referred to this species by M. Merian cannot positively be said to belong
to it.

Formation.—Terrain 4 Chailles, Corallien.

Localities—Fringeli, Canton de Soleure.
Corallien de Besancon, du département de |’Yonne.
Nattheim, Wirttemberg. Formation «, Quenst., d’'Ulm, Wiirttemberg.

Collections —Museum of Vienna (Dudressier Collection).
British Museum.

Crparis Droaiaca. Cotteau, Etudes sur les Hchinides Foss., p. 111, t. 11, figs. 1, 2.

Test very large, inflated, depressed both on the upper and under surfaces; tubercles
large and prominent; bosses large, with deeply crenulated summits; uppermost plates of
the inter-ambulacra with rudimentary tubercles, destitute of areolas; scrobicular circle
elliptical; granules large and perforated ; granules of the miliary zone likewise large, distant,
and perforated ; ambulacra narrow, with two rows of perforated granules; poriferous zones
very narrow ; pores very small and contiguous.

Formation.—Calcaire a Chailles de Druyes (Yonne).
Coral Rag Inferieur de Chatel-Censoir.

Localities—Druyes, Chatel-Censoir, Yonne.

Collection —M. Cotteau, Ecdle des Mines, Paris.
Plaster mould, in my Cabinet, sent by M. Cotteau.

Ciparis Suzvica. Desor, Synopsis des Echinides Foss., p-\7,.t-d fig. 2.

Test large, inflated, depressed on the upper and under surfaces; areolas circular,
deeply excavated; bosses prominent, summits finely and deeply crenulated ; tubercles
moderate sized ; miliary zone covered with a fine, abundant, homogeneous granulation ;
scrobicular circle with granules of the same size as those filling the zone; ambulacra with
two rows of unequal-sized granules.

Formation—Argovien P
Locality.—W irttemberg.

Collections —Museums of Tiibingen, Zurich.

62 FOREIGN OOLITIC CIDARIDA.

Ciparis propinava. Miinst., im Goldfuss, Petrefact., p. 119, t. 40, fig. 1.
Agassiz, Echin. Fos. Suisse, 1, p. 62, t. 21, figs. 5, 6, 7, 9, 10.

Test small, depressed; ambulacra much flexed, with two rows of marginal granules ;
poriferous zones narrow, sunk; pores small, contiguous; inter-ambulacra with four or
five plates only ; areolas small; bosses small, summits nearly smooth; tubercles very large
and prominent; scrobicular circles complete, touching, formed of prominent spaced-out
granules. Spines short, elliptical, clavate; stems much swollen out in the middle, and tapering
to a point at their distal extremity, covered with longitudinal rows of large, distinct granules.

Formation.—Coral Rag, Jura blanc, (Argovien étage ?)

Localities. —Baireuth.
Argovien des Legern, du Randen.
Argovien (formation y, Quwenstedt) Sirchingen, Wiirttemberg.
Environs de Metz, Moselle.

Collections.—-Museums of Zurich, Bale, Tibingen, Neuchatel.
British Museum, my Cabinet.

CrpaRis ELEGANS. Miinst., in Goldfuss, Petrefact., p. 115, t. 39, fig. 5.

Test small, depressed; areolas small, circular; tubercles large and prominent, bosses
crenulated ; scrobicular circle formed of spaced-out granules; ambulacra with two rows
of marginal granules. Spines short, clavate; stem covered with small granules.

Formation.—Coral Rag of Baireuth, Bavaria.
Coral Rag of Nattheim, Sigmaringen, Wiirttemberg. Formation «, Quenst.

Collections. —Museums of Bonn, Tibingen, Stuttgart, my Cabinet.

CrpaRis coronata.—Goldf., Petrefact., p. 119, t. 39, fig. 8.
Agassiz, Echinod. Foss. Suisse, 1, p. 59, t. 20, figs. 8—17.
Quenstedt, Petrefactenkunde, t. 48, figs. 16—21, with beautiful
and accurate details.
Desor, Synopsis des Echinides Foss., p. 9, t. 1, fig. 1.

FOREIGN OOLITIC CIDARID A. ; 63

Test moderate sized, much depressed ; ambulacra flexuous and prominent, with four
rows of small, close-set granules in the middle, diminishing to two rows in the upper and
lower parts of the area; poriferous zones sunk; pores small, round, contiguous ; inter-
ambulacra with from four to five plates in each column; areolas large, circular ; rim pro-
minent, surmounted by a scrobicular circle of round, prominent, spaced-out granules ;
bosses with feebly crenulated summits above, nearly, if not quite, smooth below ; tubercles
large and prominent; disc opening very large; miliary zone filled with numerous small,
round granules; a considerable granulated space between the scrobicular circles. Spines
round, with the head large; neck long, smooth; stem swollen out, and then gradually
tapering to a blunt point; surface covered with a confluent granulation, arranged in
parallel carinated, longitudinal lines.

Formation —Coral Rag of Sigmaringen, Wiirttemberg, and Bavaria. Formation y,
Quenstedt.
Coral Rag Inferieur, et Calcaire a Chailles, Chatel-Censoir et Druyes,
Yonne.

Collections —In all the Foreign Collections.
British Museum, Bristol Museum, Scarborough Museum. It is often
mistaken for and ticketed as a British fossil. My Cabinet.

Ciparis MARGINATA. Goldf., Petrefact., p. 118, t. 39, fig. 7.

Test nearly as large as Cidaris Blumenbachit, slightly depressed at both poles ; ambu-
lacra prominent, with six rows of small, compressed granules in the middle of the area,
diminishing to four rows above and below; five or six pairs of plates in the inter-ambu-
lacra; the areolas large, circular, and much excavated ; margin prominent, and surrounded
with a circle of scrobicular granules, not much larger than those filling the miliary zone ;
bosses small, with smooth summits; tubercles large; poriferous zones deeply sunk ; pores
small, round, and contiguous; miliary zone wide, filled with small, close-set granulations.
Spines round; head and acetabulum large, with a smooth rim; neck thick, short, and
smooth ; stem covered with lines of granules.

Formation —Coral Rag of Nattheim. Formation «, Quenstedt.
Jura Superieur Heidenheim.

Collections.—Museums of Bonn, Tiibingen, Stuttgart, and others.
British Museum, my Cabinet.

64 a FOREIGN OOLITIC CIDARID A.

D. Species from the Kimmeridge Clay.

Crparis Botoniensis, Wright, nov. sp., 1855. Figured in Mr. Davidson’s MSS., pl. 1,
Mesh Wk use

Form unknown, plates and spines only found. Ambulacra very narrow, with two rows
of small granules ; poriferous zones as wide as the areas; pores oblong, separated by thick
septa; inter-ambulacra wide, plates twice and a half as broad as they are deep; areolas
elliptical, central, much excavated; bosses small, summits broad and deeply crenulated ;
tubercles large, gradually increasing in size from below upwards; scrobicular circle com-
plete im the upper areolas; granules small, a little larger than those in the zone; miliary
zone wide; the granules diminish in size between the scrobicular circle and the centro-
sutural line; a second miliary zone between the scrobicular circle and the poriferous zones.
Spines long, cylindrical, or a little compressed; head very large; rim of the acetabulum
deeply crenulated; ring very prominent, forming a carina milled with microscopic lines ;
neck long, lower half covered with fine longitudinal lines, upper half smooth; stem nearly
round, and closely covered with small granular longitudinal lines, compressed at the ex-
tremity; arising, at irregular intervals, from among the granular lines, are a number of
short, stout, thorn-like, forward-directed prickles; in some of the more spatulate varieties
of the spies the prickles are not conspicuous, but in the round forms they are very
prominent processes.

M. Bouchard Chantereaux, of Boulogne, who kindly sent me the specimens, at the same
time states, “they are the only dééris of the species that I have yet found. If we may
judge of the size of this urchin by the dimensions of the tubercular plates, this species
must have been at least four times larger than Hemicidaris Boloniensis, which you have
now.”

This Cidaris was most accurately figured in detail by my excellent frend Mr.
Davidson, in Pl. I of an ‘ Atlas of Plates illustrative of the Fossils of the Boulonnais,’ and
which plates have been most obligingly placed at my disposal for this work.

Formation.—Kimmeridge Clay, near Boulogne-sur-Mer.

Collections. —M. Bouchard Chantereaux, Mr. Davidson, my Cabinet.

FOREIGN OOLITIC CIDARID AL. 65

Genus—RABDOCIDARIS.
B. Species from the Inferior Oolite.

RaspociDaris MAXIMA. Syn. Cidarites maximus. Miinst., in Goldf., Petrefact., p. 116,
fig Oy, fl,

Test large, very high, having at least seven tubercular plates in each inter-ambulacral
column; areolas large, elliptical, confluent; bosses with deeply crenulated summits ;
tubercles large ; scrobicular circles incomplete ; granules small, not larger than those filling
the miliary zones; ambulacra broad, with two rows of marginal granules, and an interspace
between ; poriferous zones nearly straight, and broad; pores oblong, wide apart. Spines
long, round; head large, neck long and smooth, stem swollen out in the middle; surface
armed with irregularly disposed, forward-directed, thorny spines.

Formation.—Inferior Oolite of Baireuth. Formation, Brauner Jura 6, Queast.

Collection —Museums of Bonn and Stuttgart ; plates and spine in my Cabinet.

C. Species from the Coral Crag.

RaBDOCIDARIS NOBILIS. Syn. Cidarites nobilis. Mimst., m Goldf., Petrefact., p. 117,

t. 39, fig. 4.
_ Agassiz, Echinod. Foss. Suisse, u1, p. 65,
t. 21 a, fig. 21.
Desor, Synopsis Echinides Foss., t. 8,
ng. 10.

Test large, thin, spheroidal, depressed at both poles; ambulacra broad, slightly flexed,
with six rows of small granules; poriferous zones narrow ; pores small, round, separated
by thick septa: mter-ambulacra wide; seven large plates in each column; areolas large,
circular, superficial; bosses small, not prominent, summits deeply crenulated; tubercles
large and prominent ; scrobicular circles complete ; granules small, a little larger than those
fillimg up the zones. The scrobicular circles of the lower plates touch ; those of the upper
plates are separated by a miliary space; miliary zone very wide, covered with numerous
granules, which diminish in size from the scrobicular circle to the centro-sutural line,
which is very distinctly visible. Spines long, cylindrical or sub-prismatic; the head
large; neck smooth, concave; stem very long, sometimes twelve inches in length, Quenstedt;

| 9

66 FOREIGN OOLITIC CIDARID A.

surface covered with short, thorn-like, forward-directed prickles, which in prismatic varieties
are disposed in lines; base of the stem slightly enlarged; the remainder of the stem is
narrower, and of a uniform width throughout.

Formation.—White Jura (Argovien) ? Baireuth.
White Jura, Coral Rag, Wiirttemberg. Formation <, Quenst.

Collections.—Museums of Vienna, Tubingen, Stuttgart.
British Museum, my Cabinet.

D. Species from the Kimmeridge Clay.

RABDOCIDARIS ORBIGNYANA. Desor, Synopsis des Echinides Fossiles, p- 40, t. 1, fig. 3.

Test large, spheroidal ; ambulacra broad, flat, with four rows of granules; poriferous
zones as wide as the area; pores small, round, placed far apart by thick septa; inter-
ambulacra with seven or eight plates in a column; areola circular, superficial ; boss promi-
nent, summit broad and deeply crenulated; tubercles large and widely perforated ; scrobi-
cular circles complete ; granules small, well spaced out, and raised on abase; miliary zone
moderately wide, and filled with small granules, which gradually diminish in size between
the scrobicular circle and the centro-sutural line, which is well defined. Spines long, tri-
carinate or prismatic, from three to four inches in length; sometimes they are compressed
and flattened near their distal extremity ; the head is small, the rim of the acetabulum is
deeply crenulated, the rg is narrow, the neck short and smooth; at the base, and along
the edges of the carine, there are rows of stout, short, forward-directed, thorn-lke prickles ;
the intermediate surface of the stem is covered with longitudinal lines of small, irregular-

sized granules.
Formation —Kimmeridge Clay, Rochelle, Villersville, Cap la Heéve, Havre.

Collections —MM. Michelin, Cotteau, Thurmann.
British Museum, Jermyn Street Museum, my Cabinet.

FOREIGN OOLITIC CIDARID A. 67

Genus—DIPLOCID ARIS.

DipLocipaRis GigaANTEA. Syn. Cidaris gigantea. Agass., Echin. Foss. Suisse, ii, p. 66,
t. 21, fig. 22.

a hs Quenstedt, Petrefactenkunde, t. 48,
fig. 45.
Diplocidaris gigantea. Desor, Synopsis Echinides Foss.,
te ee, 5:

Test large; ambulacra straight, with two rows of marginal granules; poriferous zones
wide ; pores bigeminal throughout; interambulacra wide; areolas superficial, small in
proportion to the size of the plates; bossal summits deeply crenulated ; tubercles small
and perforated ; scrobicular circle composed of large, mammillated, spaced-out granules.
Miliary zone wide, filled with granules placed wide apart; between the areolas and the
poriferous zones, there is a wide miliary zone ; the uppermost plates of the inter-ambulacra
are destitute of primary tubercles, the miliary granules covering their entire surface. Spines
stout, cylindrical; stem covered with numerous equal-sized granules, which are nearly
longitudinal in their disposition, but have no connecting calcareous filament ; acetabulum
large, rim deeply crenulated, ring prominent, neck short and smooth.

Formation.—Coral Rag of Besancon, Salins, Chatel-Censoir, and Druyes, Yonne.
Coral Rag of Nattheim, “‘ Weissen Jura, &., bei Ulm,” Quwenst.
Wittemberg.

Collections —Museum of Vienna (Dudressier Collection), Tiibingen, Collections of

M. Cotteau and M. Michelin.

68 HEMICIDARID A.

Family 2—TEMIcIDARIDE.

Test thick, spheroidal, more or less depressed; mouth opening large, central; peris-
tome decagonal, and divided by notches, more or less deep, into ten unequal-sized lobes.

Apical disc small, directly opposite the mouth, composed of five genital plates, and
five ocular plates; the anterior pair of genital plates are larger than the posterior pair,
and the right antero-lateral, which always supports the madreporiform body, is the largest.
Anal opening round or oval in the centre of the genital circle.

Ambulacral areas wider than in the Crpartp#&, with semi-tubercles at their base only,
as in Hemicidaris, or extended throughout the area as in Acrocidaris ; these tubercles are
perforated, and provided with crenulated bosses like those occupying the inter-ambulacra ;
the areas are straight or undulated.

Inter-ambulacral areas wide, composed of large plates, rarely more than eight in each
column ; the external surface of the plates supports large perforated tubercles, raised on
very prominent bosses; the areolas are in general oblong, and confluent above and below ;
the incomplete scrobicular semicircles form two crescents on the sides, and they alone
form the narrow, central, miliary zone. One small group, Acropeltis, has the bosses
smooth, and the tubercles imperforate.

The poriferous zones are narrow and undulated; the pores are small, contiguous,
and unigeminal throughout, except near the peristome, where they are bigeminal and
trigeminal.

The jaws are large and powerful, and armed with stout tricarinate teeth. ‘The spines
im general are long, cylindrical, and tapering; sometimes they are claviform or stout,
compressed, and angular. Their surface is in general covered with fine longitudinal lines ;
but, as far as we know, neither prickles nor asperities are developed on the stem.

I have grouped in this family the genera Hemicidaris, Acrocidaris, and Acropeltis,
which are all extinct, and found in the Oolitic, Cretaceous, and Tertiary Formations.

HEMICIDARIS. 69

Genus—HEMICIDARIS, Agassiz. 1840.

CrpaRiTEs (pars), Lamarck. 1816.
CrDARITES (pars), Goldfuss. 1829.
DrapemMa (pars), Desmoulins. 1835.

The genus Hemicidaris was established by Agassiz,* to receive certain urchins which
Lamarck and Goldfuss had included in the genus Cidarites, and Desmoulins had placed
among his Diademas. The dismemberment of these forms from the genera with which
they had been associated, was an important progressive step in stratigraphical paleeon-
tology, as they form extinct types of the Echinoidea, which, up to the present time,
have only been found in the Oolitic, Cretaceous, and Nummulitic Formations.

The species of this genus exhibit a group of characters which are easily recognised,
even when portions of the test only are preserved.

If the reader will please to compare Plates I and II with Plates III and IV of this
work, he will discover at a glance how widely different the general /wczes and structure of
the test in Hemicidaris is from that of the true Crdaris.

The Hemicidaris, in general, have the test thick, of a medium size, more or less sub-
globose, and generally flattened at the base; the altitude being greater in proportion to the
latitude than in either the Ciparipa, Diapemapa, or Ecuinip#. The distinctive character
of the genus lies in the structure of the ambulacral areas, which are narrow, and more or less
flexuous. At the enlarged base of each area (PI. IV, fig. 1 4, c, d) there are three or four
pairs of mammillated tubercles, which occupy the lower fourth part of the area. ‘These
semi-tubercles are smaller in size, but identical in structure, with the primary tubercles of the
inter-ambulacral areas, and, like them, they gradually increase in magnitude from below
upwards. The upper three fourths of the area has two marginal rows of minute perforated
tubercles, which contrast strongly with the large semi-tubercles they immediately succeed.
Between the minute marginal tubercles there is a narrow miliary zone, containing two or
more rows of small, close-set granules.

The poriferous zones are narrow ; the pores are unigeminal, and approximated on the
sides, but near the peristome they become bigeminal and trigeminal, according as the
space in that region is more or less augmented.

The inter-ambulacral areas are wide, with two rows of primary tubercles, from four to
eight in each row. ‘hey have large, prominent bosses, with deeply crenulated summits,
especially those near the equator of the test; the areolas are wide, and mostly confluent
above and below, so that the scrobicular circle of granules is generally incomplete. In
some species the tubercles increase and diminish gradually im the area; in others,

* ‘Description des Echinodermes Fossiles de la Suisse,’ part ii, p. 42.

70 HEMICIDARIS.

the large equatorial tubercles are succeeded by others, which diminish suddenly in
s1ze.

The mouth opening is large; the peristome is decagonal, its margin bemg always
divided into ten lobes by deep notches; .the five jaws, when preserved (Pl. IV, fig. 1 4),
are always large and powerful.

The apical disc is small, its elements are very solid, and so well articulated with
the areal plates, that it is very often preserved in the fossil state. It forms, in this respect,
a remarkable contrast to the apical disc in Cidaris, which is large, and almost always
absent. The anterior pair of genital plates are larger than the posterior pair, the right
antero-lateral plate being the largest, and always supporting a prominent spongy madre-
poriform body; the single posterior plate is often small and rudimentary, from the
encroachment of the vent; the five ocular plates are small, prominent, heart-shaped bodies.
with marginal orbits, whereas the oviductal holes of the genital plates are pierced at some
distance from the border; the surface of all the discal elements is covered with small
granules. |

The primary spines are in general long, tapering, and cylindrical, but sometimes they
are Claviform; their surface is smooth, and sculptured with fine longitudinal lines
(Pl. IV, fig. 1 2, 2, 0); the secondary spines are small, short blunt processes (fig. 1 J, 4).

The size of the species in this genus varies from half an inch to two inches in diameter,
and from two tenths of an inch to an inch and three quarters in altitude.

Hemicidaris is distinguished from Cidaris by the breadth and structure of the ambu- —
lacra, and the presence of semi-tubercles at the bases of these areas. It is distinguished
from Diadema by the narrowness of the ambulacra, and the presence of minute marginal
tubercles only on the sides of the ambulacra, Diadema having primary tubercles as large
as those in the inter-ambulacra, ranging throughout these divisions of the test.

Hemicidaris very much resembles Acrosalenia, many species of this latter genus
having been mistaken for the former. //emicidaris may be readily distinguished by the
great difference in size between the uppermost pair of semi-tubercles and the lowest pair
of minute marginal tubercles, but, above all, by the size of the discal opening, and the
structure of the apical disc itself, which in Acrosalenia has one or more sur-anal plates;
even when the elements of the disc are absent, there is always a certain amount of
excentricity in the opening, one angle thereof intruding farther down the single inter-
ambulacrum than into either of the other inter-ambulacral areas.

Hemicidaris is distinguished from Acrocidaris by the narrowness of the ambulacra,
and by the semi-tubercles being limited to the bases of the areas, whereas in Acrocidaris
the ambulacra are wide, and furnished with primary tubercles throughout; each of the genital
plates likewise is furnished with a large perforated tubercle, raised on a crenulated boss.

The genus /emicidaris may be subdivided into three sections, of each of which we
have typical examples in our Oolitic formations :

FROM THE INFERIOR OOLITE. 71

Section a.—Test elevated, tubercles large in the upper parts of the inter-ambulacra.
Examples: Hemicidaris intermedia, Hemicidaris crenularis, Hemi-
cidaris Bravenderi.

Section 4.—Test large, depressed ; tubercles suddenly diminishing in size on the upper
part of the inter-ambulacra.

Examples: Hemicidaris diademata, Hemicidaris Stokesii, Hemicidaris
pustulosa.

Section e.—Test in general small; ambulacra very flexuous; tubercles in the inter-
ambulacra few in number, but large in size, and very prominent.
Examples : Hemicidaris minor, Hemicidaris Thurmanni.

A. Species from the Inferior Oolite.=10th Btage, Bajocien, VOrbigny.

Hemicrparts eranuLosa, Wright. Pl. III, fig. 2 a—/.

HEMICIDARIS GRANULOSA. Wright, Annals and Magazine of Natural History, 2d series,
vol. viii, p. 257, pl. ii, fig. 4 a, a.
— — Desor, Synopsis des Echinides Fossiles, p. 55.
— — Morris, Catalogue of British Fossils, 2d edit., p. 82.

‘Test sub-spheroidal, depressed at both poles ; ambulacral areas straight, with two mar-
ginal rows of prominent, well-defined, imperforate granules, and three pairs of semi-tubercles
at the bases thereof; inter-ambulacral areas, with three pairs of primary tubercles, extending
only as far as the equator, the upper tubercular plates being covered with warty granules ;

apical disc large, and not prominent; base flat; mouth opening large; peristome slightly
notched. |

Dimensions.—Height, seven tenths of an inch; transverse diameter, one inch and one
tenth.

Description.—This remarkable Urchin is closely allied to Hemicidaris pustulosa, Agassiz,
and replaces that Dorsetshire species in the same zone of the Inferior Oolite at Dundry-
The test is hemispherical, flat below, and slightly depressed above (PI. III, fig. 2 ¢); the
ambulacral areas are straight and prominent, they have two marginal rows of from ten to
twelve large, prominent, imperforate granules, which are smooth and deformed, and set
regularly in alternate rows, the intervening surface of the plates being filled with small,
ill-defined, and irregularly arranged miliary granules (PI. III, fig. 2 d); the bases of the
areas are wide, to allow of the development of three pairs of moderately sized semi-tubercles
(Pl. III, fig. 2 4); the poriferous zones are nearly straight, except where they follow the

72 HEMICIDARIS.

basal expansion of the areas; the pairs of pores (PI. III, fig. 2 d) are placed slightly
oblique, and the septa have raised eminences, which form a moniliform division between
the pores; there are ten to eleven pores opposite each large tubercular plate, and at the
wide basal region of the zones they fall into triple oblique pairs.

The inter-ambulacral areas are twice and a half the width of the ambulacral ; they had
from six to seven large plates in each column, the three or four inferior plates alone sup-
porting large primary tubercles; the three upper plates are destitute of them, and, in lieu
thereof, have clusters of granules, similar im size to those of the ambulacra, developed on
their surface, and forming triangular, quadrangular, or pentagonal figures, according to the
number of granules in each group (PI. III, fig. 2 a); the large primary tubercles occupy
the entire surface of the rhomboidal plate (fig. 2d); the boss is large and prominent
(fig. 2 e), its summit is deeply crenulated, and the tubercle is likewise large and deeply
perforated; the areolas are smooth and gently inclined (fig. 2 e), and around them is a
complete scrobicular circle, formed of from thirteen to fifteen round granules (fig. 2 d);
the base is flat (Pl. III, fig. 2 4); the mouth opening is very large, thirteen twentieths of
an inch, that of the diameter of the test being one inch and two tenths; the peristome is
not so deeply notched as in many other congeneric forms.

The apical dise is concealed by hard adherent rock in the larger specimen, but is well
exposed in a smaller one (fig. 2 a); it consists (fig. 2,7) of elongated heptagonal genital
plates, the one carrying the madreporiform body is the largest ; the oviductal holes are pierced
near the apices; the ocular plates are distinctly heart-shaped, with a depression down the
centre of each, the orbit being formed by the notch; the disc makes a slight prominence
on the upper part of the test, and the surface of the plates is destitute of any sculpture ;
the anal aperture is circular and central (fig. 2).

Affinities and differences.—This Urchin very much resembles Hemicidaris pustulosa,
Agassiz, but is distinguished from it in having narrower ambulacra, with larger, fewer, and
more prominent granules thereon; the inter-ambulacra have likewise fewer primary tuber-
cles, and their areolas are surrounded with complete circles of well-spaced-out scrobicular
granules (fig. 2 d, e), whereas in Hemicidaris pustulosa the areolas are confluent.

It is distinguished from /emicidaris intermedia by the absence of tubercles from the
upper parts of the inter-ambulacra, and by the form and size of the granules covering the
ambulacra. It is so entirely distinct from all other congeneric forms, that it is impossible
to mistake it for either of them.

Locality and Stratigraphical position—The two specimens figured in PI. III, fig. 2,
were collected from the Inferior Oolite of Dundry Hill, associated with Diadema depressum,
Echinus germinans, and Polycyphus Forbesii. In My. Lowe’s cabinet there is a fine
specimen of this species, showing the base very well, which was collected from the Forest
Marble near Corsham, Wilts.

FROM THE INFERIOR OOLITE. 73.

Listory.—This species was first figured in my ‘Memoirs on the Cidaride of the
Oolites,’ published in the ‘ Annals of Natural History,’ October, 1851. It is a very rare
Urchin ; fine specimens of it are contained in the British Museum, Bristol Museum, and
in my collection ; the only known localities are those already mentioned.

Hemiciparis pustutosa, Agassiz. Pl. II, fig. 1 a, 3, ¢,d, e.

HEMicrparis PusTULOSA. Agassiz, Catalogus Systematicus, p. 8.
— — Agassiz and Desor, Catalogue raisonné Annales des Sciences
Naturelles, 3° série Zool. tome vi, p. 338.
— — Desor, Synopsis des Bchinides Fossiles, p. 53.
— — D’Orbigny, Prodrome de Paléontologie, tome i, p. 320, No. 420.

Test large and sub-conoidal ; ambulacral areas wide and straight ; semi-tubercles large,
wide asunder, upper part covered with homogeneous granules, those on the margins the
largest ; inter-ambulacral areas narrow, with two rows of prominent primary tubercles,
which disappear a little way above the equator; the uppermost four or five tubercular
plates have clusters of from six to ten homogeneous granules developed on their surface ;
apical disc large and very prominent, the elements thereof forming a considerable elevation
on the test; mouth opening large. Spines thick, oval, with a ridge on one side.

Dimensions.—a. Agassiz’s type specimen, from the Great Oolite, Ranville. Height,
one inch and one twentieth of an inch; transverse diameter, one
inch and seven tenths of an inch.

B. Height of the specimen figured (PI. III, fig. 1), seven tenths of an
inch; transverse diameter, one inch and three tenths of an inch.

Description.—In the examination of the species of the genus Hemicidaris, the palon-
tologist often experiences much difficulty in finding on the test alone good characters for
the separation of forms which, from the study of the entire organism, he knows to be dis-
tinct, but which, were he to rely merely upon the shell, he would pronounce to be identical ;
this circumstance has doubtless led to much confusion among the members of this group ;
no such difficulty, however, exists in the species now under consideration, as it is marked
by characters so prominent and well defined, that when it is once seen it cannot possibly
be mistaken for any but one of its congeners.

Hemicidaris pustulosa was first discovered by Professor Deslongchamps, in the Great
Oolite of Normandy, and entered by Agassiz in his ‘Catalogus Systematicus. These
specimens have been most kindly communicated to me by Professor Deslongchamps.
But it has never, until now, been either figured or described.

The test is large, with a broad base; it is inflated about the equator; from this point

10

74 HEMICIDARIS.

the shell rises into a sub-conoidal form, with a prominent and elevated apical summit; the
ambulacral areas are wide and nearly straight, so much so that I have received specimens
from France that were ticketed as Diadema; the base of the areas is expanded, and there
are from six to seven pairs of semi-tubercles in this region, which are well spaced out and
very prominent, with a small granule at the angle of each zigzag interspace ; the upper
part of the areas has two marginal rows of imperforate granules, not very regular, however,
in their arrangement, and between them are several smaller granules, equally irregular in
size and disposition; the poriferous zones are rather wavy and of moderate width; the
pores have an elevated granule rising from the surface of the septa, and separating them,
which produces a moniliform line in the track of the zones; the pairs of pores are nearly
horizontal, and unigeminal, from the disc to the equator; the zones at this point bend
outwards, to form enlarged spaces for the basal semi-tubercles; as the zones approach
the peristome, the pores lie in triple oblique pairs.

The inter-ambulacral areas at the equator are only twice the width of the ambulacral
areas (Pl. III, fig. 1 4), and, what is very unusual among the Hchinide, they are more
prominent than the ambulacra; the primary tubercles are limited to the inferior and
middle parts of the areas, one or two only extending above the equator of the test (PI. III,
fig. 1 c); they are surrounded by areolas, which are confluent both above and below, and
have semicircles of five or six pustulose granules on their outer and inner margins. On
the upper part of the areas the true tubercles disappear (PI. III, fig. 1 a); the surface
of the tubercular plates in this region develops only clusters of granules, which are
very irregular in their mode of arrangement, but uniform in size and form; the first
tubercular plates above those having true primary tubercles have a small imperforate
tubercle in the centre, and a cluster of granules around it, but the three or four plates
between this and the disc are covered with a homogeneous granulation ; the areolas of the
primary tubercles are separated from the poriferous zones by semicircles of granules (PI. II,
fig. 1 c), and like semicircles of scrobicular granules separate the areolas in the median
line from each other; there are from eight to ten plates in each tubercular column.

The apical disc is large and very prominent, and forms a conspicuous elevation at the
summit of the sub-conoidal test (Pl. III, fig. 1 a, e); the antero-lateral genital plates are
the largest ; the postero-laterals nearly equal them in size and figure, and the single plate
is the smallest ; the madreporiform body forms a kind of warty eminence on the surface of
the right antero-lateral plate, which is the largest ; the ocular plates are heart-shaped, and
project like tubercles from between the angles formed by the genital plates ; the surface of
all the elements of the disc, the genital, and even the ocular plates, is covered with
numerous granules. (PI. III, fig. 1 e.)

‘The spines are only known by a fragment, which is imbedded in the base of a specimen
from St. Aubin de Langrune. This spine is thick and oval, with a ridge on one of its sides,

The mouth opening is large, and the peristome is not deeply notched ; the anal opening
is obliquely oval.

FROM THE STONESFIELD SLATE. 75

Affinities and differences.—YVhis species closely resembles Hemicidaris granulosa in the
presence of granules instead of tubercles, on the upper part of the test. It is distinguished
from it by the following characters: the form is more conoidal, the ambulacra are wider,
the granules on the same are smaller and more numerous; the scrobicular circles are
incomplete, and the surface of the plates of the apical disc is covered with granules.
Hemicidaris pustulosa resembles Hemicidaris Stokesii (Pl. III, fig. 3) in the sudden
diminution in the size of the tubercles on the upper parts of the inter-ambulacral areas,
and in the granulated character of the surface of the apical disc; but it is distinguished
from that species in having unequal-sized, irregularly disposed marginal granules on the
ambulacral areas. ‘I'he tubercles of the two upper inter-ambulacral plates in Hemicidaris
Stokesii ave perforated, with distinct scrobicular circles around their areolas (PI. III,
fig. 3 a); whereas in Hemicidaris pustulosa the rudimentary tubercles and the scrobicular
granules form clusters on the plates (PI. II, fig. 1 a). The elements of the apical disc,
in both species, are much alike in form, structure, and sculpture. ‘The disc, however, in
Hemicidaris Stokesii does not rise above the surface ; whereas in Hemicidaris pustulosa it
forms a marked projection. There is no other Oolitic species of Hemicidaris at present
known for which Hemcidaris pustulosa can be mistaken.

Locality and Stratigraphical position.—The only English specimen I have seen was
presented to me by my excellent friend Mr. Etheridge. The exact locality in Dorset-
shire from whence it was collected, however, is not known; but, judging from the litho-
logical character of the rock in which it is imbedded, it is probable it came from the Inferior
Oolite near Bridport.

The French specimens were found in the ‘‘ Grand Oolite (Bathonien), de Luc, St.
Aubin, Langrune, Calvados.” —Deslongchamps.

History.—This species was first entered in the ‘Catalogus Systematicus’ of Agassiz,
and afterwards in the ‘Catalogue raisonné’ of Agassiz and Desor, but it is now figured
and described for the first time.

B. Species from the Stonesfield Slate, Great Oolite, Bradford Clay, Forest Mardle,
and Cornbrash=11th Htage, Bathonien, WV Orbigny.
Hemiciparis Stoxesit, Wright, nov. sp., Pl. III, fig. 3 a, 4, c.

CIDARIs FROM STonEsFieLD. Stokes, Transactions of the Geological Society of London,
2d series, vol. ii, pl. 45, fig. 17.

Test circular, depressed; ambulacral areas straight, with two rows of small regular
marginal tubercles; inter-ambulacral areas with large primary tubercles at the equator,

76 HEMICIDARIS.

and disproportionately small tubercles on the upper parts of the area; apical disc large,
and composed of nearly equal-sized plates.

Dimensions.—Antero-posterior diameter, one inch and five tenths. Height unknown.

Description.—This beautiful species has been hitherto overlooked by English paleon-
tologists, notwithstanding the very excellent figure given of it in the Transactions of the
Geological Society, 2d series, by the late Mr. Charles Stokes. I have not been able to
discover the original specimen, but through the kindness of Professor John Phillips, of
Oxford, I am enabled to figure a much better specimen, recently discovered by him at
Stonesfield. Unfortunately the upper surface of this specimen, like that figured by
Mr. Stokes, is alone exposed, the under surface being irremoveably surrounded by the
rock.

The ambulacral areas are straight, and rather wide; they are provided with two
marginal rows of small tubercles, set on slightly prominent elevations (fig. 3 4); a few small
miliary granules form incomplete circlets around their base; the under surface and
semi-tubercles are concealed ; but the apex is not much narrowed, and forms a rather
obtuse arch (in the figure the ambulacra is drawn rather too lanceolate), over the summit
of which the heart-shaped prominent ocular plates are rather conspicuously placed.

The inter-ambulacral areas are nearly three times the width of the ambulacra; the
primary tubercles are large and prominent at the equator of the test, but they suddenly
diminish in size at the upper part of the areas, so that the two upper tubercles of each
row are disproportionately small when compared with those at the equator. The bosses
of the large tubercles rise prominently from a narrow areola, and are sculptured with about
twenty crenulations at their summits; the areola is surrounded with a complete circle of
small round scrobicular granules (fig. 3 4) ; the pores in the zones are small, and placed
widely apart, the rounded surface of the thick septa forming a moniliform line down the
middle of the zone.

The apical disc is large (fig. 3c); the genital plates are of nearly the same size; the
madreporiform body is spongy and prominent, and occupies almost the whole of the surface
of the right antero-lateral plate, which is the largest; the genital foramina open at the
centre of mammillated elevations, near the apices of the plates; there are two small
tubercles near the base of the postero-lateral and single plates, and four on the surface of
the left antero-lateral, as if the pair belonging to the right antero-lateral plate had been
transposed to its fellow of the left side, in consequence of the madreporiform body occu-
pying nearly all the surface of the right plate ; the anal opening is central and circular ;
the ocular plates form lieart-shaped elevations around the circumference of the disc; each
of the three anterior ocular plates support two small tubercles, but on the posterior pair
there is only one on each plate.

The under surface of the test is unfortunately so much embedded in the rock, that its

FROM THE STONESFIELD SLATE. gy |

removal therefrom is impossible ; we are, therefore, in ignorance about many important
points relating to the anatomy of this species.

Affinities and differences.—Hemicidaris Stokesvi resembles Hemicidaris pustulosa and
Hemicidaris diademata, in having straight ambulacral areas and disproportionately small
tubercles on the upper parts of the inter-ambulacra. From Hemiciduris pustulosa it is
readily distinguished by its regular rows of small marginal tubercles in the ambulacral
areas, with miliary granules between them, and in having small, single, primary tubercles
only on the upper parts of the inter-ambulacral areas, but no clusters of granules thereon,
as in Hemicidaris pustulosa. ‘The test likewise is much more depressed, and the apical
disc is not so prominent. Professor Agassiz observes* of Hemicidaris diademata, that
the essential character consists in the rapid diminution of the large tubercles on the
upper part of the inter-ambulacral areas; a unique peculiarity in this genus, forming a
remarkable contrast to the exuberance of these same tubercles in other species of
Hemicidaris. The discovery, however, of Hemicidaris pustulosa and Hemicidaris Stohesii,
show that this character is shared in common with other congeneric forms. From
Hemicidaris diademata this species is distinguished by having the ambulacral areas
straighter, the tubercles on the upper parts of the inter-ambulacral areas larger; and the
miliary granules are likewise larger and less numerous than those which cover the plates
in Hemicidaris diademata ; but in other respects, as far as I can make a comparison,
there is a very close affinity between these species.

Locality and Statigraphical range.—This species was first collected by the late
Mr. Charles Stokes, from the Stonesfield Slate at Stonesfield; and the urchin I figure
was collected from the same rock and locality by Professor John Phillips, who has kindly
communicated the specimen for my monograph. In the Stonesfield Slate at Eyeford,
Gloucestershire, a portion of a Hemicidaris has been occasionally found, which belongs
likewise to this species. When we consider the enormous surface of this rock which is
annually exposed by the splitting of the same into slates, and the very few specimens
that have been found during the many years the quarries have been worked, we must
consider Hemicidaris Stokesii as one of the rarest species of our Oolitic Urchins.

History.—F¥irst figured by Mr. Stokes, in the Transactions of the Geological Society ;
as the type specimen appears to have been unknown, and as it was not named by its dis-
coverer, it was not entered in our lists of species. It is now described for the first time.
The specimen figured belongs to the Oxford Museum; I have prepared plaster moulds
from the same for the British Museum, Geological Museum, Jermyn Street, and the
Bristol Institution.

* «Kchinodermes Fossiles de la Suisse,’ part ii, p. 49.

78 HEMICIDARIS.

Hemiciparis Luctensis, d’Orbigny, Pl. III, fig. 6 a, 4, ¢, d,e, f.

Hemiciparis Luciznsis. D’Orbigny, Prodrome de Paléontologie, tome i, p. 320.
— — Desor, Synopsis des Echinides Fossiles, p. 52.
— CONFLUENS. Forbes, Memoirs of the Geological Survey, Decade V, description
of pl. 5. Notes on Hemicidaris.

Test sub-spheroidal, flat at the base, and depressed on the upper surface ; ambulacral
areas straight below, siuous above, more especially in large adult individuals ; four pairs
of semi-tubercles, which increase gradually in size from the peristome upwards; two
marginal rows of small tubercles perforate and crenulate, with intervening miliary granules
below, but imperforate and approximated above ; inter-ambulacral areas with from six to
seven pairs of primary tubercles; apical disc prominent; base flat; mouth opening large ;
peristome with nearly equal-sized lobes.

Dimensions.—a. Height, seven tenths of an inch; transverse diameter, one inch and

three twentieths of an inch. «
B. Height, eleven twentieths of an imch; transverse diameter, one
inch.

c. Height, five tenths of an inch; transverse diameter, eight tenths of
an inch.

Description—This Hemicidaris, it appears, was mistaken on the Continent for
Hemicidaris crenularis, Lamarck, of the Coral Rag, from which it has been with justice
separated by M. d’Orbigny ; it has, up to the present time, been overlooked as an English
urchin, the specimens hitherto found at Minchinhampton having been almost indeter-
minable. One specimen, however, collected from a band of clay in the Great Oolite, and
communicated by my friend Mr. Lycett, has enabled me to compare this form with a good
series of type specimens sent from Luc, Ranville, and Langrune, by MM. Michelin and
Deslongchamps ; so that the English specimens are found to occur in the same geological
horizon as the original French types.

‘The test is thick and sub-spheroidal, with a flat base, and a depressed summit (PI. ITI,
fig. 6 c); the ambulacral areas are narrow, slightly sinuous in young shells, but much
more markedly so in large specimens; their bases are a little expanded, to give space to
the four or five pairs of semi-tubercles (fig. 6 4), which gradually increase in size from the
peristome to the last pair; the upper portions of the areas are provided with two marginal
rows of small tubercles (fig. 6 a), set tolerably wide apart, and alternating with each other;
two rows of close-set miliary granules occupy the middle of the area (fig. 6 @), and circlets
of the same surround the small marginal tubercles; on the upper part of the areas two
rows of marginal granules alone fill up the entire areal space (fig. 6 ¢); the poriferous

FROM THE GREAT OOLITE. 79

zones (fig. 6 d) are narrow; the pairs of pores are placed obliquely upwards and outwards ;
between each pair there is a small elevated granule; these interporous granules form a
moniliform undulated line, which marks the course of the zones.

The inter-ambulacral areas are very regularly formed, they are three times the
width of the ambulacral areas, and occupied by two rows of primary tubercles, from six to
seven in each row, which increase very regularly in size from the peristome to the equator,
and diminish in like manner as they approach the apical disc; the areolas are large
and circular ; those of the five or six lower tubercles are confluent above and below, one
row of miliary granules forms a series of crescents, which surround their inner margin,
separating them from the poriferous zones, and two rows of the same-sized granules form a
narrow zigzag inter-tubercular space down the middle of the areas; the two uppermost
plates of the tubercular columns have the small tubercles they develop, alone surrounded by
a distinct and contmuous circle of scrobicular granules; the three largest areolas are
channeled at their circumference ; the mammuillary bosses have a wide base, and are very
prominent ; their summits are deeply crenulated; the tubercles are moderately large ; they
have a short stem, and are deeply perforated.

The apical disc (fig. 6 f) is large and prominent; the antero-lateral genital plates are
much the largest; the postero-lateral are longer and narrower, and the single posterior
plate is the smallest and narrowest; the right antero-lateral plate, as usual, supports a
conspicuous madreporiform body; the eye plates are heart-shaped, and nearly all of the
same size, and the whole of the elements of the disc are covered with small close-set miliary
granules ; the anal opening is large, and widest in its transverse diameter.

The base is flat, and the mouth-opening (fig. 6 4), especially in the larger specimens,
is very wide, being rather more than half the diameter of the test; the lobes of the peris-
tome are nearly equal in size, those of the ambulacral being a little larger than those of
the inter-ambulacral areas.

Affinities and differences.—Hemicidaris Luciensis very much resembles Hemicidaris
Wrightii, Desor, but it is distinguished from that species by having less prominent
ambulacra, without the rows of granules which fill up the area in that form. Like
as in Hemicidaris Wrightiz, the apical disc is very prominent, and the surface of the plates
is covered with numerous granules.

Hemicidaris Luciensis is distinguished from Hemicidaris Bravenderi by having less
prominent marginal granules in the ambulacra, a smaller and more prominent apical disc ;
the mouth opening is more unequally lobed; and it is altogether a smaller and more
depressed form. Although the critical distinction between these Bathonian species is
sufficiently clear, still they have so many affinities in common, that unless the specimens
are well preserved, and the determination is carefully made, they may be readily mistaken
for each other.

80 HEMICIDARIS.

Locality and Stratigraphical position.—This species has been collected from the Great
Oolite of Minchinhampton. Many small specimens are found in the Oolitic shelly beds,
but they are not well preserved. One or two specimens in good preservation have been
found in a Clay seam of the samerock. In France it has been collected from the Bathonien
“Calcaire & polypiers,” 11th Etage, d’ Ordigny (Great Oolite of English authors), at Lue,
Langrune, Ranville, Calvados.

- History.—M. d’Orbigny, in 1847, separated this urchin from Hemicidaris crenularis,
with which, he says, he was confounded by M. Agassiz. He further observes, it is easily
distinguished from Hemicidaris crenularis by a much greater number of small tubercles
between the large inter-ambulacral tubercles; but this is clearly a mistake, for both spe-
cies have two rows of close-set granules down the centro-sutural line. The difference
resides more in the structure of the ambulacra, and in the size and prominence of the
apical disc, than in the number and arrangement of the inter-ambulacral granules. It is
now figured and described for the first time.

Hemiciaris Minor, Agassiz. PI. III, fig. 5 a, 6, ¢, d.

HEMICIDARIS MINOR. Agassiz, Catalogus Systematicus, p. 9.
— — Agassiz and Desor, Catalogue raisonné des Echinides, Annales
des Sciences Naturelles, tom. vi, p. 339, 3d series.
ACROSALENIA RARISPINA. M‘Coy, Annals of Natural History, 2d series, vol. u, p. 411.
HEMICIDARIS MINOR. Wright, Annals of Natural History, 2d series, vol. xiii, pl. 2,
fig. 3 a—c, p. 165.
= — Desor, Synopsis des Echinides Fossiles, p- 56.
= = Morris, Catalogue Brit. Foss. 2d edit., additional species of Echi-
nodermata.

Test hemispherical above, flat at the base; ambulacral areas slightly flexuous, not
prominent, with six large semi-tubercles at the base, and four rows of small, unequal-
sized granules in the middle, diminishing to two rows in the upper part of the areas;
inter-ambulacral areas three times the width of the ambulacral, with three primary tuber-
cles on the upper surface, and three smaller ones at the base; the wide miliary
zones are covered with small, distinct, nearly equal-sized miliary granules, which form
complete circles around the margins of the areolas of the primary tubercles; the apical
disc is of moderate size, and its ovarial plates are covered with a delicate granulation ;
base flat, mouth opening large, peristome unequally decagonal, pores arranged in the zones
in single pairs throughout.

Dimensions.—Height, three tenths of an inch; transverse diameter, nine twentieths
of an inch,

FROM THE GREAT OOLITE. 81

Description.—This beautiful little urchin was first discovered in the Btage Bathonien of
Langrune, Calvados, the true equivalent of the Great Oolite of English geologists. It was
entered in M. Agassiz’s ‘ Catalogus Systematicus’* as Hemicidaris minor, from specimens
sent to him by M. Michelin. It afterwards found a place in the ‘ Catalogue raisonné des
Echinides’ of Agassiz and Desor, accompanied with this remark: “Se distingue entre
tous les Hemicidaris par les tubercules trés espacés, dont il n’y a que deux ou trois dans
une rangee. ‘Terrain Jurassique de France.”—MWichelin. Professor M‘Coy, in his paper
‘On some new Mesozoic Radiata,’} afterwards described this urchin under the name
Acrosalenia rarispina, giving the Great Oolite of Minchinhampton for its locality.

As that gentleman has kindly favoured me with pen-and-ink sketches of the species
described as new in his paper, I have no difficulty in deciding on the identity of his
specimen. Moreover, I have ascertained the collection from whence it originally came.
The error committed by this author in the genus must have arisen from the disc in his
urchin having been covered with “adhering siliceous matrix,” and from his having
overlooked the very remarkable character pointed out by Agassiz, “les tubercules trés
espacés.”

I have been fortunate enough, through the kindness of my friend Prof. Deslongchamps,
to receive a typical specimen of the original species from the Great Oolite of Langrune,
which I have compared with specimens obtained from the same locality as that
whence Professor M‘Coy’s was collected, and there is not a shadow of a doubt about
their perfect identity. This pretty little Hemicidaris is very distinct from all others of
the group to which it belongs. The test is nearly hemispherical (fig. 5 a), and the few
primary tubercules stand prominently, at great distances apart from the surface of the test.
The narrow ambulacral areas are slightly flexuous above, and have from four to six semi-
tubercles at their base; the sides and upper part of the areas having first four (fig. 5 c),
and then two rows of small, imperforate granules upon their surface, about equal in size to
the granulation which covers other parts of the test.

The poriferous zones are depressed, and the pedal pores disposed in pairs through-
out (fig. 5 c); there are twelve pairs of pores opposite each of the large tubercular plates.
The inter-ambulacral areas depart considerably from the typical structure of this portion
of the test in the Hemicidaride (fig. 5 a); they are three times the width of the
ambulacra, and have at their base three large primary tubercles, two on one side and
one on the other, with a smaller tubercle above the single large one (fig. 5 4); on the sides
and upper part of the areas there are only three primary tubercles, two on one side and
one on the other, making only three pairs of primary tubercles in the inter-ambulacral
areas, those of the base being closely set together, and those on the sides at great distances
apart (fig. 5 a, 4); the tubercles are large and hemispherical, and only slightly perforated
(fig. 5 c); the mammillary eminences which support them are small and ring-like, (fig. 5 a),

* «Catalogus Systematicus Ectyporum Echinoderm. Foss. Mus. Neocomensis,’ 1840.

+ ‘Annals of Natural History,’ 2d series, vol. ii, p. 411.
11

82 HEMICIDARIS.

with faintly marked crenulations ; the areolas are rather wide, and only slightly grooved,
so that the tubercles project prominently and abruptly from the surface of the test. The
margin of the areola is encircled by a row of thirteen granules (fig. 5 c, d), rather larger
than those which cover the rest of the inter-tubercular surface of the plates. The miliary
granules are close-set, and disposed without much regularity on the surface of the plates.
The apical disc (fig. 5 6) is of moderate size, and slightly prominent; the five ovarial
plates are large, and of a heptagonal form; the ocular plates are small and heart-shaped,
and the surface of both is covered with a close-set, delicate granulation; the anal opening
is nearly central, and circular; the base is flat; the mouth opening is large and widely
decagonal, from the great size of the ambulacral lobes, and the comparative smallness of
the inter-ambulacral. The spines are as yet unknown.

Afimties and differences.—This remarkable little urchin is so entirely different from
its congeners, that it is impossible to mistake it for any other of the group to which it
belongs. The presence of semi-tubercles at the base of the ambulacral areas only, and of
granules on the sides of these spaces, associate it with Hemicidaris diademata, but the
small number of the primary tubercles on the inter-ambulacral areas, added to the great
distance at which they are placed apart, serve to distinguish it from the young of that
species ; in fact, these characters alone are perfectly diagnostic of Hemicidaris minor among
all other forms of Hemicidaris.

Locality and Stratigraphical position —lt was first found in the “ Grand Oolite” of
Langrune, Calvados, whence the beautiful specimen before me was obtained, and kindly
sent by Professor Deslongchamps, of Caen. I take the present opportunity of recording
my grateful acknowledgements to that eminent naturalist for his kindness and courtesy,
not only in contributing specimens to my cabinet for comparison and reference, but like-
wise for communicating many rare species of Oolitic Hchinidze, which served as the types
of several of M. Agassiz’s new species, and which specimens have been of much service to
me in clearing up doubts as to the identity of some other English forms.

Henicidaris minor was collected in this country by W. Walton, Esq., from the Great
Oolite of Hampton, near Bath. I have never found this species in the Great Oolite of
Minchinhampton, nor have I seen it in any collection of fossils from that locality.

History.—First named by M. Agassiz from specimens in Professor Deslongchamps
and M. Michelin’s collections ; afterwards described as Acrosalenia rarispina by Professor
M‘Coy, from specimens in the Cambridge Museum, which came from Mr. Walton’s series,
collected near Bath. It was figured and described in detail, for the first time, in my
contributions to the Palaeontology of Gloucestershire, published in the ‘Annals and
Magazine of Natural History’ for 1854.

FROM THE GREAT OOLITE. 83

Hemiciparis Ramsayu, Wright, nov. sp. Pl. VIII, fig. 6 a, 6, ¢, d, e.

Test small, circular, much depressed. Ambulacra expanded below, to enclose six large
semi-tubercles ; very narrow and flexuous above, with two rows of small imperforate
granules placed alternately on the margins thereof, and forming a single row only above.
Poriferous zones narrow; pores set obliquely in pairs, with a prominent elevation of the
septa. Inter-ambulacra wide, with two rows of very large tubercles, four or five in each
row. Apical disc large and prominent; the genital plates with a depression near their
centre; mouth opening large; peristome decagonal, with unequal-sized lobes.

Dimensions.—Height, one fifth of an inch; transverse diameter, two fifths of an
inch.

Description.—This is the smallest, but certainly not one of the least interesting of the
genus to which it belongs. It is remarkable for the disproportionate magnitude of three
of the primary inter-ambulacral tubercles to the smallness of the test that supports them ;
the size and prominence of the elements of the apical disc; and the altitude being only
one half the latitude of the test. These three characters readily distinguish this little
gem from all its other congeners.

The ambulacral areas are wide, and expanded below, to enclose from six to eight semi-
tubercles (Pl. VIII, fig. 6 @), which are nearly as large as the inter-ambulacral tubercles in
the same region of the test; they increase gradually in size, from below upwards, the two
superior pairs being the largest; above the semi-tubercles the area suddenly contracts
(fig. 6 d), and becomes flexuous above; on its margins there are two rows of small imper-
forate granules, which, from the extreme narrowness of the area above, form only a single
row as they approach the apical disc; the poriferous zones are narrow; the pores are set
obliquely in pairs ; and the thick septum forms a prominent granule, which separates the
two pores forming a pair; there are seven pairs of pores, opposite one of the large inter-
ambulacral plates.

The wide inter-ambulacral areas are almost entirely occupied by the two rows
of primary tubercles, which, in this species, are much larger in proportion to the size of the
test than in any other urchin. ‘There are four or five plates in each inter-ambulacral
column ; almost the entire surface of the plate is occupied by the base of the large
prominent boss (fig. 6d), the summit of which is sculptured with fine crenulations ; the
tubercles are very large, especially the two at the circumference, and one in each area above
them (fig. 6 4); on the upper part of these there is one small tubercle, near the
circumference of the apical disc ; a double row of small granules extends down the middle
of the area, which sends short branches off at right angles, by which the areas are

84 HEMICIDARIS.

separated from each other (fig.6d); but there are no granules between the boss and the
poriferous zone (fig. 6 d).

The apical disc is large, and beautifully preserved in one of the two specimens
before me; it forms a considerable prominence on the upper surface of the test (fig. 6 4) ;
the genital plates have a heptagonal form, are very thick, and have a remarkable depression
near their centre, at the bottom of which the oviductal tubes appear to open (fig. 6 e); the
anterior pair of plates are the largest, the posterior pair are rather smaller, and the single
plate is the smallest; the right antero-lateral, carrying a small madreporiform body in its
depression, is the largest of the series; the ocular plates are small heart-shaped bodies ;
the vent is slightly pentagonal, excentral, and posterior.

The mouth opening is one half the diameter of the test, it has a decagonal form, and
the peristome is slightly notched ; the ambulacral lobes are larger than the inter-ambulacral ;
the base is flat, and the tubercles of both areas on this region of the test are nearly all of
the same size (fig.6 c); the different appearance which the test presents when viewed
on its under surface (fig. 6c), and on its upper surface (fig. 6 4), is very marked indeed.

Affinities and differences—The only Hemicidaris this little form can possibly be
mistaken for is Hemicidaris minor (PI. III, fig. 5), with which it is associated in the same
bed and locality ; but it is readily distinguished from that species by its depressed form,
and by the inter-ambulacral areas being crowded with large prominent tubercles, raised
on very prominent bosses; the ambulacral areas are likewise much narrower above,
and the space for the semi-tubercles is much wider below; in fact, the remote-
ness of the tubercles from each other in Hemicidaris minor, is as good a diagnostic
character of that species, as the disproportionate largeness of the tubercles, and their
consequent crowding near the circumference of the test, is of Hemicidaris Ramsayit.

Locality and Stratigraphical position—This rare little urchin was collected from the
shelly ferruginous beds of the Great Oolite, at Sham Castle, near Bath, associated with
Hemicidaris minor, Acrosalenia spinosa, and other Great Oolite forms. I dedicate this
species to my friend, Professor Andrew C. Ramsay, F.R.S., Director of the Geological
Survey of Great Britain.

Hezmiciparis BravenDErti, Wright, nov. sp. PI.V, fig. 1 a, 6,¢,d,e,f. Pl. XI, fig. 3 a, 4, ¢.

CIDARIS CRENULARIS. Murchison, Geology of Cheltenham, 2d edit., Buckman and Strick-
land, pl. 13, p. 73.

Test sub-globular, flattened at the base; ambulacral areas nearly straight, with two
marginal rows of minute, well spaced out, perforated tubercles, and six pairs of moderate
sized semi-tubercles ; inter-ambulacral areas with two rows of moderate sized primary

FROM THE GREAT OOLITE. 85

tubercles, eight in each row, gradually decreasing in size from the equator to both poles ;
apical disc large, anal opening excentral behind; mouth opening large; peristome divided
into ten nearly equal sized lobes.

Dimensions. —Height, nine tenths of an inch; transverse diameter, one inch and one
fifth of an inch.

Description.—It is exceedingly difficult to detect on the test alone of many allied
species of Hemicidaris, characters sufficiently well marked to distinguish them from
each other. When these forms, however, are found with their spines, the distinction
is in general so evident, that the difficulty at once disappears; but when deprived
of these appendages, the diagnosis becomes obscure. This is well exemplified in several
species, and strikingly so in the one now under consideration. At the first glance
Hemicidaris Bravendert would be taken by most persons for Hemicidaris inter-
media; but the details of its structure afford sufficient evidence of its distinctness
from that Corallian type. The test is sub-globular, not much inflated at the base; the
ambulacral areas are nearly straight, being only slightly undulated in the upper third; on
the margin of the areas there are two rows of small perforated tubercles, from fifteen to
sixteen in each row; raised on small bosses, and placed rather widely apart ; two rows of
microscopic miliary granules extend down the centre of the areas, and lateral branches form
circlets around the areolas (fig. 1 ¢); the semi-tubercles are not large, but are regular as to
form, size, and arrangement, the six pairs gradually decreasing in magnitude from the
upper or largest pair, to the smallest or most inferior pair, which extend to the margin of
the ambulacral lobe (fig. 1 4).

The inter-ambulacral areas (fig. 1 4), are nearly three and a half times the width of the
ambulacral areas; thew two rows of primary tubercles decrease gradually in size
from the equator, where they are largest, to both poles; there are seven tubercles in each
row; the bosses (fig. 1 4, c, @) are prominent, and their summits have from fourteen to
sixteen crenulations, not, however, deeply marked; the spinigerous tubercle is small, and
finely perforated; the areolas are wide and confluent (fig. 1 ¢) above and below ; down
the centre of the area (fig. 1a, 4) a zig-zag double row of small tubercles, slightly
perforated, and raised on little eminences (fig. 1c), separates the two rows of primary
tubercles from each other; small miliary granules fill up the interspaces at the base of
these elevations ; a single row of the same sized small, perforated tubercles separates the
areolas from the poriferous zones (fig. 1c) ; among these, likewise, a few miliary granules
are irregularly distributed.

The base is flat (fig. 1 4), and nearly two thirds of the whole is occupied by the mouth
opening, which is more than one half the diameter of the shell at the equator; the
peristome is deeply notched, and divided into ten nearly equal sized lobes (fig. 1 e), and
the margin of the notches is reflexed.

86 HEMICIDARIS.

The apical disc (fig. 1,7) is large ; the antero-lateral ovarial plates are the largest, and
the surface of the right plate is entirely covered by the madreporiform body ; the postero-
lateral plates are smaller, and the right is smaller than the left plate; the odd genital plate
is the smallest, and the surface of all the plates is slightly roughened, with small
imperfectly developed miliary granules ; the genital holes are situated near the apices of the
plates (fig. 1); the ocular plates are small, heart-shaped, and convex, and form a very
inconsiderable portion of the disc; they likewise are covered with numerous small miliary
granules; the anal opening (fig. 1 a, /) is large, circular, and slightly excentral.

The test of Hemicidaris Bravendert, on the slab (PI. XI, fig. 3 a), measures one inch and
one fifth, and the longest spine measures three inches in length; the head is small and
conical ; the milled ring is narrow, and not very prominent ; immediately above the ring
there is a smooth, narrow, slightly depressed neck, not broader than the thickness of the
milled ring ; the stem is slender in proportion to its length, and preserves a very uniform
diameter throughout, tapering very gently to the point; the spies of Hemicidaris
Bravenderi differ from those of Hemicidaris intermedia, (P|. IV, fig. 1) m the following
details :—the spine is longer in proportion to the diameter of the test ; the head is smaller ;
the milled ring is narrower, and less prominent; the neck is smooth and slightly contracted,
instead of having a thick prominent second ring, as in Hemicidaris intermedia ;
(Pl. IV, fig. 1 2, 0) the diameter of the spine is less at the base, and more uniform, tapering
less than the spine of Memicidaris intermedia. In fact, the specific distinction between
these closely allied species is admirably shown in the spines alone, when the two specimens,
figured in Plate IV and Plate XI, are placed side by side.

Affinities and differences.—It requires a minute and careful comparison of the tests to
distinguish the differences between Hemicidaris Bravenderi and Hemicidaris intermedia.
In Hemicidaris Bravendert the ambulacral areas are straighter, the marginal tubercles
are smaller and fewer, being situated at a greater distance from each other; the semi-
tubercles are likewise smaller, and not so conspicuous; the primary tubercles have lower
bosses, less deeply crenulated at the summit, and the spinigerous tubercles are much
smaller; the apical disc is proportionately larger, and the inequality of size between the antero-
lateral and postero-lateral genital plates occasions a slight excentricity m the anal opening,
not observable in Hemicidaris intermedia (PI. IV, fig. 1 a, g); the lower part of the test
is likewise less inflated than in Hemicidaris intermedia (P1. IV, fig. 1 c); it is altogether
a smaller form, with less prominent primary tubercles, semi-tubercles, and minute tubercles,
than those which adorn the shell of Hemicidaris intermedia. From Hemicidaris Luciensis
(Pl. III, fig. 6) it is distinguished by having the test more globose, with straighter and
wider ambulacral areas, and smaller semi-tubercles ; the apical disc is not so convex and pro-
minent ; the mouth opening is larger, and its peristome is likewise divided into more nearly
equal-sized lobes. ‘The absence of primary tubercles from the upper parts of the inter-

FROM THE GREAT OOLITE. 87

ambulacral areas in Hemicidaris pustulosa (P). III, fig. 1) and Hemicidaris granulosa
(Pl. III, fig. 2) distinguish at a glance these species from Hemicidaris Bravenderi.

In its sub-globose form it much resembles Hemicidaris Davidsoni (P1. IV, fig. 2), but
it is distinguished from that Portland species in having wider ambulacral areas, with the
minute tubercles thereon both longitudinally and laterally more widely apart; the semi-
tubercles are likewise much smaller, and disposed: regularly in pairs, whereas they run (in
many specimens) into a single row in Hemicidaris Davidsoni (P\. IV, fig. 2 6, c). ‘The
size of the anal opening in the latter is much greater, so much so, that the right postero-
lateral and odd genital plates are greatly reduced in size. Hemicidaris Bravenderi resembles
Hemicidaris Purbeckensis (Pl. V, fig. 4) in the straightness of the ambulacral areas, but
these divisions of the shell are wider, and the minute marginal tubercles are set wider apart
in the former species; the semi-tubercles, likewise, are more regularly disposed in pairs
than in the Purbeck form (Pl. IV, fig. 4 4), where they assume a linear arrangement.
The sudden diminution in the size of the primary tubercles on the upper parts of the
inter-ambulacral areas in Hemicidaris Stokesii (Pl. Ill, fig. 3) at once separates that
Stonesfield slate species from Hemicidaris Bravenderi.

Locality and Stratigraphical position.—This species belongs to the Bathonian Oolitic
zone. It has been collected from the Great Oolite of Kull-Devil Hill, near Cirencester,
by Mr. J. Brown of that town, but the specimen, formerly in the collection of that gentleman,
now presented to the British Museum, is unfortunately not well conserved. Mr. Bravender,
F.G.S., of Cirencester, found a fine specimen of this species, with its spines attached, in the
Great Oolite at Stratton, near Cirencester, which was figured by Mr. Buckman in the ‘Geology
of Cheltenham.’ Its zoological characters are very well preserved. This species was col-
lected by Mr. Bristow, of the Geological Survey, from the Cornbrash, in a lane leading from
Stourton Caundle to Lower Woodacre. ‘This fine specimen is in the Museum of Practical
Geology, Jermyn Street, and has been admirably figured by Mr. Bone for this Monograph.
Hemicidaris Bravenderi is found, likewise, in the Great Oolite of Langrune, Calvados. I
have specimens from that locality kindly sent me by Professor Deslongchamps and
M. Tesson, of Caen.

LMstory.—First figured, without description, as Hemicedaris crenularis in the ‘ Geology
of Cheltenham,’ and noticed by Professor Forbes in his Note on the species of Hemicidaris
found in British strata, ‘Memoir of the Geological Survey,’ Decade III: “This fine
species,” he observes, ‘“‘is very distinct from any other British one, resembling most nearly
Hemicidaris intermedia, but differing in having gradually, not suddenly, increasing ambu-
lacral areas, with the tubercles upon them set 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 species,
Hemicidaris crenularis.” ‘The detailed diagnosis of the points of difference between

88 HEMICIDARIS.

Hemicidaris Bravendert and Hemicidaris intermedia apply with equal truth as between
our species and MHemicidaris crenularis, which differs from Hemicidaris intermedia chiefly
in the form of its spines. The test is now figured in detail and described for the first
time. I dedicate the species to Mr. Bravender, F.G.S., of Cirencester, who first found
this urchin in 1844, at Stratton, near Cirencester, and to whom I am indebted for the
loan of the original specimen with spines, figured in PI. XI, fig. 3.

Hemiciparis Wricuti, Desor. PI. V, fig. 2 a, 4, ¢, d, e.

HEMICIDARIS ALPINA. Wright, on the Cidaridze of the Oolites, Annals and Magazine of
Natural History, 2d series, vol. viii, p. 256, pl. 11, fig. 3 a, 6.
_ — Forbes, Memoirs of the Geological Survey, Decade III, pl. 5.
Notes on British Species of Hemicidaris.
= — Morris, Catalogue of British Fossils, 2d ed., 1854, p. 81.
— Wricuti. Desor, Synopsis des Echinides Fossiles, p. 54.

Test sub-globose, depressed above; ambulacral areas prominent, convex, and slightly
flexuous, crowded with four rows of small miliary granules on the sides, and four semi-
tubercles at the base; primary tubercles of the inter-ambulacral areas suddenly diminishing
in size above; apical disc large, prominent, and convex.

Dimensions.—Height, nearly three fifths of an inch; transverse diameter, nine tenths
of an inch.

Description.—When this beautiful urchin was discovered some years ago, I pro-
visionally identified it with Hemicidaris alpina, Agassiz, from the peculiar structure
of the ambulacral areas. Finding that my friend Mr. S. P. Woodward had made a
like determination of a specimen contained in the collection of Mr. Lowe, and obtained
from the same locality, I figured and described it as Hemicidaris alpina, with this
remark: “I consider my urchin, however, merely a variety of the Swiss species, for
which I propose the name variety granularis.”’ My late lamented friend, Professor Edward
Forbes, had formed a similar conclusion from the specimens he examined, for he observes,
in his notes on the species of Hemicidaris found in British strata, Hemicidaris alpina,
Agassiz—“ A pretty species, easily distinguished from its congeners by the very small and
thickly-set ambulacral tubercles.” M. Desor’s knowledge of the type of Hemicidaris
alpina, Agassiz, enabled him to point out the distinctive characters between that species
and our urchin. He says—“ Hemicidaris Wrightii, Desor. Syn. Hemicidaris alpina, var.
granularis, Wright. Les ambulacres sont plus saillants et moins larges que dans le
Hemicidaris alpina ; leur rangées externes de granules sont moins accus¢es. Sur contre il
existe 4 l’intérieur de ces granules marginales quatre 4 six rangées de trés fines granelures

FROM THE GREAT OOLITE. 89

-comme dans |’espéce précédente. Les tubercules inter-ambulacraires diminuent sensible-
ment de grosseur a la face supérieure.”* The Hemicidaris alpina, Agassiz, was collected
from the upper division of the Jurassic group, “ Portlandien moyen (Kimméridgien) de Gesné
et des Ormonds (Alpes vaudoises),”’ whilst Hemicidaris Wrightii was found in the lower
division of the same group, the Bradford Clay and Forest Marble.

The test of this beautiful species is sub-globose; the ambulacral areas are slightly
undulated, and of a medium size, rather depressed above; they are prominent and convex,
of an elongated conical form, and are thickly covered with small hemispherical granules,
without perforations or other sculpture (Pl. V, fig. 2 d); the marginal rows are larger
and more regular; between them are from four to six rows of smaller granules, closely set
together. At the base of the areas are four or six mammillated and perforated semi-tubercles
(Pl. V, fig. 2 e), which are limited to this region. ‘The pores are set obliquely in pairs,
with a smooth, elevated granule between each pair, which forms a moniliform sinuous
line, running between the pores (Pl. V, fig. 2 d).

The inter-ambulacral areas are of moderate breadth, with two rows of primary tubercles,
five or six on each column. ‘The bosses of the two central tubercles are large and promi-
nent (Pl. V, fig. 2); those towards the anal and oral poles are smaller (fig. 2 a), and
they are all crenulated at their summits (fig. 27); the tubercles are deeply perforated,
and supported on a short stem, the hemispherical head of the tubercle not exceeding in
diameter that of the stem (fig. 2f); the areolas around the basis are slightly channeled,
and they are all confluent; those towards the anal pole have a circle of granules encircling
the areolas (fig. 2 a); the miliary zones are narrow, and covered with two rows of small,
smooth granules (fig. 2 4), similar in form and size to those occupying the ambulacral
areas. ‘The apical disc (fig. 2 @ and ¢) is very prominent; the ovarial plates are large,
convex, and much granulated ; the two anterior pair are larger than the posterior pair, but
the right anterior plate is the largest (fig. 2 c); the genital holes are large, and near the
apices ; the ocular plates are of a proportionate size; the spines are unknown.

The mouth opening is of moderate size, the peristome between the lobes being deeply
notched and reflexed; the pores are small, and separated by thick septa (fig. 2 7); they
are disposed in simple pairs nearly all the length of the poriferous zones, but are arranged
in double files around the border of the oral aperture, in such a manner as to occupy all
the free space in the ambulacral areas, resulting from the contraction of the inter-ambulacral
areas in the region of the mouth; the surface of the septa developes prominent convex
elevations, which form a moniliform line separating the pores of each zone.

Affinities and differences.—Our specimen is smaller in size, but, with the differences
already pointed out, it much resembles Hemicidaris Alpina, Agassiz, from the Calcaire de
Saanen, in having the ambulacral areas closely crowded with small, uniform, and hemi-

* «Synopsis des Echinides Fossiles,’ p. 54.

90 HEMICIDARIS.

spherical miliary granules ; the areas, however, are more prominent and convex, and want
the defined rows of marginal granules which characterise the Swiss specimen. It very
much resembles Hemicidaris Luciensis, d’Orbigny; but the four rows of nearly equal-
sized granules filling the ambulacral areas serve to distinguish it from that species.

Locality and Stratigraphical position.—This species was collected from the Bradford
Clay of Pickwick, Wilts. A valve of Zerebratula digona was attached to the test, and
the specimen is firmly adherent to the surface of Rhynchonella concinna. In Mr. Lowe’s
cabinet there is a fine specimen of this urchin, which was collected at Pickwick; and in
the British Museum there is another good specimen, likewise from Wiltshire. Separate
plates of this Hemicidaris have been found in the Bradford Clay at the Tetbury-road Station
of the Great Western Railway. It is, however, a rare species.

fistory.— ¥ wst figured and described in my ‘ Memoir on the Cidaridee of the Oolites,’
afterwards included in Professor Forbes’s descriptions of Jurassic Hemicidaris, in the
‘Memoirs of the Geological Survey of Great Britain,’ Decade II]; entered in the second
edition of Professor Morris’s ‘Catalogue ;’ lastly, separated from Hemzcidaris alpina by
M. Desor in his ‘ Synopsis des Echinides Fossiles.’

H&MICcIDARIS ICAUNENSIS, Cotteau. PI. III, fig. 4 a, 4.

HEMICIDARIS ICAUNENSIS. Cotteau, Etudes sur les Echinides Fossiles, p. 56, pl. 3, figs. 1—3.
— — Forbes, Memoirs of the Geological Survey, Decade III. Notes
on Hemicidaris.
— — Wright, on the Cidaridze of the Oolites, Annals and Magazine of
Natural History, 2d series, vol. vii, p. 256, pl. 11, fig. 3 a, 8.
— — Morris, Catalogue of British Fossils, p. 82, 2d edit.
— = Desor, Synopsis des Echinides Fossiles, p. 53.

Test hemisperical, inflated, and slightly depressed ; ambulacral areas with two rows of
small marginal tubercles, and with three or four pairs of semi-tubercles at the base;
inter-ambulacral areas with two ranges of primary tubercles ; mouth large and decagonal ;
margin deeply notched.

Dimensions.—Height, four fifths of an imch; transverse diameter, one inch and one
fifth.

Description.—This species is hemispherical and inflated at the sides, and its transverse
diameter is one half more than its height. The inter-ambulacral areas are furnished with
two rows of large primary tubercles ; in each range there are from six to seven tubercles,

FROM THE GREAT OOLITE. 91

which attain their greatest development at the equator of the test, and diminish in size
near the anal and buccal openings. ‘The mammillary eminences supporting the tubercles
are large, prominent, and surrounded by confluent areolas. The tubercles are small and
perforated ; one row of granules separates the large tubercles from the poriferous zones,
and a double row occupies the middle of the area. The lateral boundaries of the areolas
are surrounded by semicircles of granules, whilst the upper and lower boundaries of the
same blend into each other.

The ambulacral areas are narrow, slightly undulated, and furnished through nearly
all their extent with a double row of small tubercles, which are not very apparent, but are
larger on the sides than at the apex of the area; between the size of these and the three
pairs of semi-tubercles at the base, a sensible difference exists. The mouth opening is large,
and is one half the diameter of the test; it is of a decagonal form, with the peristome
deeply notched. ‘The apical disc is not preserved, and the spines are unknown.

Afinities and differences.—Hemicidaris icaunensis, mm its general form and charac-
ters, closely resembles Hemicidaris intermedia. It is distinguished from the latter by
having the primary tubercles of the inter-ambulacral areas less promiment, by the ambulacral
areas being less waved, and in having the semi-tubercles much smaller. This character
assimilates Hemicidaris icaunensis with Hemicidaris Thurmanni, but it is sufficiently distin-
guished from that urchin by its greater height, less undulated ambulacra, and the greater
number of tubercular plates in the inter-ambulacral areas.

Locality and Stratigraphical position.—This rare species was obtained by Mr. Lycett
from the Great Oolite of Minchinhampton. M. Cotteau collected it in France from the
superior beds of the Bathonian stage at Chatel-Censoir; and M. Bathier found it in the
Forest Marble of Chatel-Gérard, where it is likewise rare.

History.—This species was first figured and described by M. Cotteau,* and was
provisionally identified by Professor Forbes.t It is figured in Pl. a, fig. 9, of the
‘Monograph of Great Oolite Fossils,’ to be published by the Palseontographical Society.
The specimen before me, which belongs to Mr. Lycett’s collection, is only a cast; the
determination, therefore, is doubtful, but as it was made by my lamented friend, after a
careful consideration of the facts, I have adopted his views without vouching for their
accuracy. ‘I'he specimen is so imperfect, that I have followed M. Cotteau’s description.

* Echinides Foss. du Département de l’Yonne, t. 3, p. 56.
+ Memoirs of the Geological Survey; Brit. Organic Remains, Decade III, deseription of pl. 5.

92 HEMICIDARIS.

HEmIcIDARIS CoNFLUENS, J/‘Coy.

HEMICIDARIS CONFLUENS. M‘Coy, Annals and Magazine of Natural History, vol. i, new
series, p. 411.
— — Forbes, Memoirs of the Geological Survey, Decade V, Notes on
Hemicidaris.
= — Morris, Catalogue of British Fossils, 2d edition, 1854, p. 82.
= _ Wright, On the Cidaridee of the Oolites, Annals and Magazine
of Natural History, 2d series, vol. vill, p. 258.

Through the kindness of Professor Sedgwick, I have been enabled to examine the
type specimen of this urchin, which forms part of the geological collection of the University
of Cambridge. It proves to be a bad specimen of an Acrosalenia, with the test so much
defaced as to be specifically indeterminable. It unquestionably was collected from the
shelly beds of the Great Oolite of Minchinhampton. This species must now therefore be
omitted from the list of Hemicidaris.

©. Species from the Coralline Oolite, including the Calcareous Grit.=14th Etage,
Corallien, d Orbigny.

HemicipaRis IntERMEDIA, Meming. PI. IV, fig. 1 a, 6, ¢, d, e, f, g, h, 0.

CIDARIS PAPILLATA. Var. of Parkinson, Organic Remains, vol. iii, p. 14, pl. 1, fig. 6,
and pl. 4, fig. 20.
— INTERMEDIA. Fleming, British Animals (1828), p. 478.

HEMICIDARIS CRENULARIS. Morris, Catalogue of British Fossils (1843), p. 53.
HEMICIDARIS INTERMEDIA. Forbes, Memoirs of the Geological Survey, Decade III, pl. 4.
= — Wright, On the Cidaridze of the Oolites, Annals and Magazine
of Natural History, 2d series, vol. viii, p. 252.
— — Desor, Synopsis des Echinides Fossiles, p. 52.
= — Morris, Catalogue of British Fossils, 2d edition, 1854, p. 82.
CIDARIS INTERMEDIA. Phillips, Geology of Yorkshire, p. 127.
— PAPILLATA. Young and Bird, A Geological Survey of the Yorkshire Coast,
pl. 4, fig. 1, p. 211.

Test sub-globose or sub-conoidal; ambulacral areas slightly undulated above, with a
double row of minute, perforated, marginal tubercles on the sides, and six pairs of semi-
tubercles at the base; imter-ambulacral areas with eight pairs of primary tubercles, on
large prominent bosses, having deeply crenulated summits; apical disc not prominent ;
anus nearly central; mouth opening large, peristome deeply notched and divided into
ten wnequal-sized lobes. Spines long, round, and tapering to a blunt point; surface with

FROM THE CORALLINE OOLITE. 93

fine longitudinal lines; base tumid, with a prominent milled ring below, and a second
smooth ring above. Jaws large and powerful.

Dimensions —1 ec. Height, one inch and one tenth of an inch; transverse diameter,
one inch and three fifths of an inch.

1 7. Height, one inch and three fifths of an inch; transverse diameter,
one inch and three fifths of an inch.

Description.—This is one of the most common, and, at the same time, one of the most
beautiful and typical examples of the genus Hemiczdaris in our English rocks. Like its
associate, Cidaris florigemma, it has long been mistaken for a foreign species (/emi-
cidaris crenularis) which has not yet been found in our Coralline Oolites.

Had the determination of this species rested on the anatomy of the shell alone, it
would have been almost impossible to distinguish between these two species; but,
fortunately, M. Agassiz has given a fine figure and detailed description* of Hemicidaris
crenuluris of Switzerland, said to be the type of Lamarck’s species. This magnificent
specimen, with its spines attached, was found in the Corallien étage of Besancon, and
formed part of the collection of M. le Comte Dudressier, which Herr Suess informs me
is in the Imperial Museum of Vienna. Now as Lamarck’s Cidaris crenularis came from
Switzerland (‘‘ Habite, Fossile de la Suisse” +), we cannot doubt the identity of the specimen
figured by Agassiz with the Lamarckian type. These points having been settled, it is easy
to show that this English Hemzczdaris is very distinct from the Swiss one, for although the
tests can only critically be distinguished from each other, still the spines of the Swiss
urchin are so very different from the English form, that there cannot be a doubt about the
distinctness of the species. In Hemzcrdaris crenularis the spines form large clubs, which
gradually increase in diameter from the head to the extremity, whereas in Hemicidaris
intermedia they gradually taper from the head to the point.

The first good figure of Hemicidaris intermedia was given by Parkinson in his
‘Organic Remains, and described as a mammillated Echinite from Wiltshire, which
‘should perhaps be considered a variation of Cidaris papillata.”{ Mantell gave a reduced
copy of Agassiz’s figure in his ‘ Medals of Creation,’ vol. i, p. 340, observing, however,—
“This species (Hemicidaris crenularis) of mammillated Echinus is common in the Oolite of
this country, and is considered to be characteristic of the Upper Jura limestone ; it is said
to be the same as that figured by Mr. Parkinson, under the name of Cidaris mummillata,
from Calne, in Wiltshire; but I have never observed spines like those of Agassiz’s figure
in the English Oolite. These spines are not homogeneous throughout, but their central
part appears to have been of a softer texture than the external crust, as may be seen in the

* ‘Echinodermes Fossiles de la Suisse,’ seconde partie, pl. 18, figs. 23 and 24, p. 44.
+ ‘Histoire Naturelle des Animaux sans Vertebres,’ 2d édit. tome iii, p. 384.
t Parkinson, ‘ Organic Remains,’ vol. iii, p. 14.

94 HEMICIDARIS.

figure where the spines are imperfect.”* The figure given by Young and Bird of
Hemicidaris intermedia found in the Coralline Oolite of Yorkshire is so bad, that, had 1
not seen the specimens said to be the type of this figure, and which were undeniable
specimens, I should have hesitated before includig it in the list of synonyms. The
description of the species, however, by Mr. Young,+ is very accurate, and is, at the
same time, the first given of this species. Dr. Fleming} described it under the name
Cidaris intermedia, giving, as its specific character—‘‘ Lesser compartments half the width
of the larger ones; tubercles crenulated at the base :’’ which was rather a generic than a
specific diagnosis. :

Hemicidaris intermedia is sub-globose, varying from a depressed spheroid to a conoidal
form (Pl. III, fig. 1 ¢, 2); the upper surface is slightly depressed and the base is flat; the
ambulacral areas are narrow, and gently undulated towards the upper part; the semi-
tubercles occupy the basal third of the area; of these there are six pairs, which gradually
increase in size from the peristome upwards (PI. III, fig. 1 4); the two uppermost pairs are
rather prominent (fig. 1 d); the sides of the areas support two marginal rows of minute,
perforated tubercles (fig. 1 d), raised on small elevations—a few microscopic miliary granules
separate the rows, and form semi-circlets around the base of the eminences ; the poriferous
zones are much undulated, especially in the upper part; the pores are in pairs throughout
the zones as far down as the third pair of semi-tubercles, where they become irregular, and
fall into oblique rows, having three pairs in each; five or six such oblique rows extend to
the peristome, and fill up the space left by the smallness of the lower semi-tubercles. There
are eleven pairs of pores opposite one of the large plates at the equator.

The inter-ambulacral areas are more than three times the width of the ambulacral, and
furnished with eight pairs of large, prominent, primary tubercles (fig. 1 c); the mam-
millary bosses form prominent projecting cones (fig. 1 e), the areolas of which touch those
of the adjoming ones in the same range; the areolated spaces of the plates im each row
are therefore confluent (fig. 1 d); down the middle of the areas, and following the zigzag
centro-sutural line, there is a conspicuous double row of small, well-marked, perforated
tubercles (fig. 1 d), amongst which some minute miliary granules are scattered; there are
seven of these small tubercles round the centro-sutural edges of each of the larger tubercular
plates (fig. 1 d); a single row of the same sized small tubercles separates the external or
zonal border of the areas from the poriferous zones, there being about six small tubercles
around the edge of each large plate (fig. 1 d). By this arrangement the upper and lower
boundaries of the areolas surrounding the bosses are confluent, whilst the outer and inner
boundaries thereof are surrounded by the small tubercles described (fig. 1 d). The summits
of the bosses are deeply sculptured with fourteen well-marked crenulations (fig. 1 d, e) ; the
tubercles are large and deeply crenulated (fig. 1 ¢), and maintain their proportional size on
the upper part of the areas (fig. 1 a).

* «Medals of Creation,’ vol. i, p. 344. + ‘British Animals,’ p. 478.
t ‘A Geological Survey of the Yorkshire Coast,’ p. 211.

FROM THE CORALLINE OOLITE. 95

The apical disc is about one fourth the diameter of the test (fig. 1 a); the antero-lateral
pairs of genital plates are the largest, the postero-lateral are smaller, and the single plate is
the smallest (fig. 1 g) ; the madreporiform bod y occupies all the surface of the right antero-
lateral plate, which is the largest ; the genital holes are situated near the apices of the
plates ; the ocular plates are heart-shaped. They form very inconspicuous elements of the
dise in this species. The eyeholes are very minute, and marginal, and situated opposite
the truncated apices of the ambulacra ; (fig. 1 @) the surface of both the genital and ocular
plates is covered with numerous minute miliary granules, very irregularly arranged.

The mouth opening is wide, occupying three fifths of the under surface (fig. 1 4); the
peristome is deeply notched, and the edge thereof is reflexed at the junction between each
inter-ambulacral series and the wide part of the poriferous-zones; the lobes of the
peristome are of unequal size, those of the ambulacral division being nearly one third
wider (fig. 1 4) than those of the inter-ambulacral.

The five jaws are large and powerful, and are preserved iz situ in several specimens
in my cabinet (fig. 1 4); each jaw has a broad, external, convex surface (fig. 1 /), and
two lateral ridges, with intervening furrows. The jaw consists of two halves, and the
symphysis extends through the middle of the central ridge.

In many specimens of this urchin the spines are admirably preserved in connection
with the test (fig. 1 2). ‘The primary spines are long, tapering, and nearly cylindrical.
They grow in length to nearly twice the diameter of the test to which they belong, some
of them measuring three inches and three quarters (fig. 1 2) ; they are closely and minutely
striated in the longitudinal direction, but the strize are rather broader than the raised
interstices. The base of each spme has a narrow elevation, or second smooth ring, just
above the milled ring, which is prominent, and deeply crenulated (fig. 1 0) ; the acetabulum
is likewise crenulated round its rim. The secondary spines, which are attached to the minute
marginal tubercles of the ambulacra, and to the tubercles of the same size in the inter-
ambulacra (fig. 1 4, 2), are small, compressed, and spatulate-shaped ; their surface is like-
wise covered with longitudinal lines (fig. 1 4), the neck is encircled with a small milled
ring, and a second smooth ring. Some of them measure one fifth of an inch in length.
On some well-preserved specimens from the Clay Beds, I have occasionally observed on the
surface of the test, when cleaning these specimens, small bodies resembling pedicellariz.

Affinities and differences.—The tests of Hemicidaris intermedia and Hemicidaris
crenularis resemble each other so much, that it is difficult to point out the distinction. Ina
fine specimen of Hemicidaris crenularis, from Lure Doubs, kindly sent me by M. Michelin,
the base is less tumid, the minute marginal tubercles on the ambulacral areas are fewer in
number and smaller, the primary tubercles of the inter-ambulacra are larger, and their
areolas are wider; the mouth opening is likewise larger, and the shell is in general higher
than in Hemicidaris intermedia. But, as I have already observed, it is in the form and
structure of the spines that the true specific distinction is found.

96 HEMICIDARIS.

The difference between this species and Hemicidaris Bravenderi has been already
pointed out in the article on that urchin, and its affinities with Hemicedaris Purbeckensis
and Hemicidaris Davidsoni will hereafter be discussed in the description of those species.

Locality and Stratigraphical position.—This species is sometimes very common, and
found in fine preservation in the Coralline Oolite at Calne, Wilts. It is collected m the
Coral Rag at Weymouth, and in the same rock near Faringdon, in Berkshire; from the
Coralline Oolite of Malton, in Yorkshire, it is likewise rarely obtained. I have before me
specimens from all these localities. From Hildenley, near Malton, some very fine shells
have been collected, but the Yorkshire specimens in general are not well preserved.

Listory.—This, in all probability, is the urchin which was figured by Martin Lister*
and by Plott, and has been always a much admired and abundant Hchinite. Until
separated by Dr. Fleming under the name Hemicidaris intermedia, it was confounded
with Hemicidaris crenularis of continental authors; and I have good reasons for believing
that it is often mistaken for that species by foreign paleontologists, as I have received speci-
mens ticketed Hemicidaris crenularis which undoubtedly belong to the English species. In
Hemicidaris intermedia the base is always much more inflated than the same region of the
test in Hemicidaris crenularis, which tapers more, and gives the shell a more globular
and elegant form. Compare, for example, our figures with the excellent drawings of
Hemicidaris crenularis, given in Goldfuss’s ‘ Petrefacta Germanie.’

D. Species from the Portland Oolite.=16th Htage Portlandien, VOrbigny.
Huemiciparis Davipsont, Wright, nov. species. Pl. IV, fig. 2 a, 4, ¢, d.

‘Test subglobose ; ambulacral areas slightly undulated, upper half with two rows of
minute marginal tubercles, Jower half occupied by an irregular row of large semi-tubercles ;
primary tubercles of the inter-ambulacral areas well developed, and gradually diminishing
in size from the equator to both poles; apical disc large, genital plates of unequal size ;
anal opening large and excentral; mouth opening large; peristome notched into nearly
equal-sized lobes.

Dimensions.—Height, nearly one inch ; transverse diameter, one inch and three tenths
of an inch.

Description.—This is the only Hemicidaris known from the Portland Beds, it is identical

* «Historia Animalium Anglize Lap. Turb.,’ p. 221, pl. 7, fig. 21, 1578.
+ ‘Natural History of Oxfordshire.’

FROM THE PORTLAND OOLITE. 97

with one collected many years ago from the Portland Sandstone of the Boulonnais by
MM. Bouchard, Chantereaux, and Davidson, and beautifully drawn by the latter gentle-
man in the first plate of his ‘Memoir on the Fossils of the Boulonnais,’ the publication of
which has been delayed until the completion of his great work on British Fossil Brachio-
poda for the Palzeontographical Society. Mr. Davidson has kindly sent me his beautiful
drawings, to make of them whatever use I may think fit; and M. Bouchard has most
generously forwarded his best specimens of this species to enable me to complete its
description. The organic characters of Hemicidaris Davidsoni are intermediate, like its
stratigraphic position, between MHemicidaris intermedia and Hemicidaris Purbeckensis.
The shell has a sub-globose form, slightly flattened at the poles; it is rather more tumid
towards the base than above; the ambulacral areas are narrow, and slightly undulated ;
the base is occupied by large semi-tubercles (Pl. IV, fig. 2 4), which are not disposed
regularly in pairs, as in Hemicidaris intermedia (PI. IV, fig. 1 c, d) ; but in consequence
of the narrowness of the areas in this region, the four upper semi-tubercles extend one
above another, forming an irregular continuous line, ascending nearly half-way
up the area (fig. 2 4); the upper half of which has two rows of minute perforated
tubercles, raised on small eminences (fig. 2 c); these tubercles, about twelve in each row,
alternate with each other, and are separated by a zigzag line of miliary microscopic granules.
The poriferous zones form a series of crescentic waves round the ambulacral sides of the
tubercular plates (fig. 2 c); the pores are in pairs, with a slightly elevated portion of the
septum between them, and there are nine pairs of pores opposite each of the large inter-
ambulacral plates; only at the base of the areas, and close to the peristome, do the pores
fall into double pairs; and of these there are only two or three rows.

The inter-ambulacral areas are more than three and a half times the width of the
ambulacral; there are eight primary tubercles on each of the two rows that fill this
division of the test ; from the equator, where they are largest, to both poles, they gradually
diminish in size; the tubercles are small, and not deeply perforated; the bosses are large
and prominent (fig. 2 ¢), with coarsely crenulated summits ; they are surrounded by wide,
smooth areolas ; each tubercular plate (fig. 2 c) has on its zonal border, between the areola
and the pores, a series of six or seven minute tubercles, raised on small eminences; and
on its centro-sutural border a series of six or seven like minute tubercles, which form
two lateral crescents around the base of the areola (fig. 2 d); the four uppermost plates
have a horizontal line of smaller granules extended across their apical border (fig. 2 a, 6)
so that the primary tubercles of these upper plates have their areolas encircled by an
uninterrupted series of granules ; but in all the lower plates they are more or less confluent
above and below (fig. 2 c). ;

The apical disc is large (fig. 2 7) ; the antero-lateral genital plates are more than twice the
size of the others; the right plate is the largest, and carries a prominent convex madrepori-
form body; the postero-lateral and single plates are much reduced in size, in consequence
of the width of the anal opening (fig. 2a/); the oviductal holes are marginal, the ocular

13

98 HEMICIDARIS.

plates are heart-shaped; the eyeholes are small and marginal; the posterior pair extend
into the anal circle in consequence of the diminution in size of the postero-lateral and
single genital plates (fig. 2 /).

The base is flat, the mouth opening is large, and occupies three fifths of this region ;
the peristome is deeply notched, the lobes are nearly of equal size, and those of the ambu-
~ lacral areas are the largest (fig. 2 e).

‘The primary spines are not jong, rarely exceeding in length one and a half times the
diameter of the test; they do not taper suddenly ; the head is short; the acetabulum is
small, crenulated on the rim, and surmounted by a prominent milled ring, beyond
which is a second ring-like elevation; the surface of the stem is covered with very fine
longitudinal lines, which are almost always effaced; the secondary spines, articulated with
the minute tubercles of the ambulacra, and those surrounding the margins of the imter-
ambulacral plates, are short, thorn-like processes. ‘This description of the spines is made
from French specimens.

Affinities and differences.—This urchin resembles very much Hemicidaris Purbeckensis,
both in its general configuration and in many points of its organization ; but differs
from it in the manner the semi-tubercles are arranged at the base of the ambulacra, in the
greater size of the apical disc and anal opening, and, above all, in the absence of the broad,
crenulated band which surrounds the body of the primary spines above the milled ring.

Locality and Stratigraphical position.—The specimen figured was collected from the
Portland Sand. Those found in the Boulonnais were collected from the Portland Beds
of the Falaise d’Alprecht, and at Ningle, by MM. Bouchard and Davidson, where it is
associated with a small elongated urchin, Hehinobrissus Haimiu, Wright, nov. sp.

HK. Species from the Marine Purbeck Beds.

Hemrcrparis Purpeckensts, Forbes. Pl. V, fig. 4 a, 4, ¢, d.

Hemicrparis PurBEecknnsis. Forbes, Memoirs of the Geological Survey, Decade III,
pl. 5. ps
= — Morris, British Fossils, 1854, 2 ed., p. 82.
— — Desor, Synopsis des Hchinides Fossiles, p. 5, pl. 11, fig. 5.

Test sub-globose ; ambulacral areas narrow and nearly straight, with five pairs of small
semi-tubercles ; inter-armbulacral areas with eight small tubercles set on moderate-sized
bosses ; apical disc composed of unequal-sized genital plates ; primary spines sub-compressed,
with a broad band of fine longitudinal lines at the base, above the prominent milled ring.

FROM THE MARINE PURBECK BEDS. 99

Dimensions.—Specimens all more or less distorted. Height, about three quarters of
an inch; transverse diameter, about one inch and three tenths.

Description —Vhe discovery of Echinoderms in the Cinder Bed of the Purbecks was
one of the rewards of the careful examination of these strata made by the officers of the
Geological Survey of Great Britain. ‘For several days,’ observed Professor Forbes,* who
found the first specimen at Swanage, in Dorsetshire, “I had found 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 distorta, Sow., 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
Hemicidaris, now first described, accompanied by its spines, identical in structure with
those previously observed.” It is this same urchin, with others since found, that my
figures represent.

The body is sub-globose, but was apparently rather depressed above; the specimens
being all more or less distorted, it is impossible to describe its form with accuracy.

The ambulacral areas are narrow, and only slightly undulated; there are two rows of
minute perforated tubercles, on miniature bosses, on the margins, about sixteen in each
row ; a zigzag line of very small granules runs down the middle of the area, and sends
small branches of granules to encircle each minute tubercle (fig. 4 4); at the base of the
area there are five pairs of small semi-tubercles, which, in a small specimen before me, have
a very regular arrangement but in the larger specimens are more diffusely disposed, so as
to alternate with considerable interspaces. The poriferous zones are slightly undulated,
the pores are small, the pairs are a little oblique, and there is a slight elevation of the
test corresponding to the septa; there are about nine or ten pairs of pores opposite
one of the large inter-ambulacral plates.

The inter-ambulacral areas at the equator are hardly three times the width of the am-
bulacral; the two rows of primary tubercles occupy the centre of the plates (fig. 1 a ) ;
the tubercles are small, set upon a smooth, slightly elevated boss, with a deeply crenulated
suminit ; around the base is a smooth, well-defined, and grooved areola; the ambulacral
and centro-sutural sides of the large plates are bordered by small, rounded granules
(fig. 4 6), some of which extend between adjacent areolas in the upper part of the areas,
but they are absent from the plates below when the areolas are confluent. The areola is
wide in comparison with the size of the boss (fig. 4 4). There are about eight primary
tubercles in each row, gradually increasing in size as they approach the equator.

The apical disc is moderately large (fig. 4 a); the antero-lateral genital plates are
much the largest; the madreporiform body occupies nearly all the surface of the

* «Memoirs of the Geological Survey,’ Decade III, description of pl. y, p. 3.

100 HEMICIDARIS.

right plate; the postero-lateral and single plates are nearly alike in size, but the single
one is the smallest ; all the genital holes are marginal ; as the anal opening is transversely
oval, and enlarged at their expense, that aperture is ‘excentral. ‘The ocular plates are
small, heart-shaped bodies, wedged im between the truncated apices of the ambulacra and
the genital plates; the eyeholes are quite marginal.

The spines (fig. 4 c, d) are sub-cylindrical, and slightly compressed on the sides; the
diameter of the largest spine is about one tenth of an inch; they are all so much weathered,
that the longitudinal lines on their surface cannot be seen; above the prominent milled
ring (fig. 4 ¢) there is a broad, well-defined space, marked with longitudinal lines,
which forms an important diagnostic mark between this species and its congeners. The
articulating head is small, and the acetabulum diminutive.

In none of the specimens is the mouth opening exposed.

Affinities and differences.—Hemicidaris Purbeckensis ditters from Hemicidaris inter-
media in having smaller tubercles and less prominent bosses. In this respect it is allied to
the Hemicidaris Bravenderi (Pl. V, fig. 1; Pl. XI, fig. 3); but the character of the spines,
with the striated space above the milled ring, distinguishes it from both. Its closest affinity
is with Hemicidaris Davidson; but trom that Portland species it is distinguished by
having narrower inter-ambulacral areas, smaller bosses, more confluent. areolas, and above
all by the comparative regularity of the semi-tubercles, which, on the contrary, extend
singly up nearly half the ambulacral areas in Hemecedaris Davidsoni (Pl. IV, fig. 2 4, c).
The apical disc is hkewise much smaller, and the vent not so wide.

HEMICIDARIS STRAMONIUM, Agassiz.

HEMICIDARIS STRAMONIUM. M‘Coy, New Mesozoic Radiata, Annalsand Magazine of Natural
History, vol. 11, new series, p. 420.
aes == Forbes, Memoirs of the Geological Survey, Decade III, notes
on Hemicidaris.
= = Morris, British Fossils, 1854, 2 ed., p. 82.

From the doubtful manner in which this species was quoted by Professor Forbes, in
his 8d Decade of the Memoirs of the Geological Survey, I requested Professor Sedgwick
to permit me to examine the type specimens belonging to the Geological Collection
of the University of Cambridge, a favour which the learned professor most kindly and
readily granted. These urchins had been labelled by Professor M‘Coy MHemicidaris
stramomium, Agassiz, and were catalogued as such in the Addenda to his Paper on some
new Mesozoic Radiata, published in the ‘ Annals of Natural History.” On examination,
these urchins proved to be two small imperfect specimens of Lemicidaris intermedia,
from the Coral Rag, Calne. On placing these specimens side by side with a true
Hlemicidaris stramonium, Agass., kindly sent me by M. Michelin, the difference between

FROM THE MARINE PURBECK BEDS. 101

them is seen to be very great. The size and prominence of the inter-ambulacral tubercles
in Hemicidaris stramonium, the magnitude and spaced-out arrangement of the semi-
tubercles at the base of the ambulacra, and the rudimentary condition of the marginal
granules on the upper half of these areas, form a group of characters by which this species
is readily distinguished from its congeners. It belongs, moreover, to beds newer than
the Kimmeridge Clay.

This species must, therefore, be omitted from our list of British Hemicidaris.

102

NOTES

On Forrien Jurassic spectus oF THE GeNUS HEMICIDARIS nearuy aLiiEeD tro

Bririsa FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EneiisH Oo ites.

HEMICIDARIS CRENULARIS. Lamarck’s (sp.), Goldf., Petrefact., p. 122, t. 40, fig. 6.
— _— Agassiz, Kchinod. Foss. Suisse, IL, p. 44, t. 18, figs. 23, 24;
t. 19, figs. 1]O—12.

= — Cotteau, Etudes Wchinides Foss., p. 122, t. 13, figs. 1—9.

Test globular, flattened at the base, and on the upper surface. Ambulacral areas
narrow, and flexuous above ; six pairs of close-set semi-tubercles at the base, and two rows
of minute tubercles on the sides, running into one row in the upper part of the areas;
inter-ambulacra with seven or eight large tubercles in each of the two rows. Mouth
opening very large, one half the diameter of the test; peristome deeply incised into ten
nearly equal sized lobes. Apical dise small.

Spines large, thick, claviform, gradually increasing in thickness from the head to the
distal extremity ; surface covered with longitudinal lines. ‘The largest spines are once and
two thirds the length of the diameter of the test; milled ring small, stem without any
apparent neck.

The greater size of the mouth opening, the depth of the notches in the peristome, the
greater equality in the size of the lobes, with less tumidity at the base of the test, added to
the claviform character of the spines, serve to distinguish this species from Hemicidaris
intermedia, which in other respects it most closely resembles.

Dimensions.—Height, one inch and one fifth ; breadth, one inch and a half.

Formation.—Corallien of Switzerland, and of France.
Coral Rag, Nattheim.

Collections.—In all Foreign Collections of Jurassic Fossils.
British Museum, my Cabinet.

FOREIGN OOLITIC HEMICIDARIS. 103

Hemiciparis ptapemaTa. Agassiz, Echinoderm. Foss. Suisse, II, p. 49, t. 19,
figs. 15—17.
Cotteau, Etudes Echinides Foss., p. 128, t. 14, figs. 1—5.

Test hemispherical, sub-inflated below, and depressed at the upper surface. Ambulacral
areas straight, wide and expanded below to enclose six pairs of large semi-tubercles ;
narrow above, with four rows of small granules; more or less irregularly disposed. Inter-
ambulacral areas with two rows of tubercles, which are large and prominent at the equator,
but are very small, and become suddenly dwarfed, on the upper surface. Apical disc
large. Mouth opening large; peristome deeply notched, divided into ten nearly equal-
sized lobes.

Dimensions.—Height, seventeen twentieths of an inch; breadth, one inch and four
tenths.

Formations.—*“ Portlandien inférieur ? Astartien de la Vallée de la Birse, de Porrentruy,
du Jura Soleurois, rare.’’—Desor.
“ Hobel, Soleure.”—d/ichelin. “ Corallien étage Driges, Yonne.”— Cott.

Collections —Museum Neuchatel. Coll. Michelin, Cotteau, Wright.

HEMIcIDARIS sTRAMONIUM. Agassiz, Echinoderm. Foss. Suisse, II, p. 47, t. 19, figs.
18, 14.

Test small, thick, sub-spheroidal. Ambulacral areas narrow and flexuous, with six or
seven large, prominent semi-tubercles, extending in a zigzag line to near the circum-
ference : upper part of the area with two marginal rows of small granules. Inter-ambulacral
areas with six tubercles in each row; the bosses are large and prominent and the
tubercles are large, especially on the upper part of the test. ‘ Spines cylindrical, with
a prominent milled ring, without a distinct neck; surface covered with small sporadic

granules.’ —Desor.

Dimensions.—Height, three fifths of an inch ; breadth, nine tenths of an inch.

Formations.—Portlandien inférieur (Astartien) de Delémont, Reedersdorf, Pfeffingen,
de Chablis (Yonne).

Collections.—Museums Neuchatel, Zurich, Bale. Coll. MM. Michelin, Cotteau.
The specimen in my Cabinet, sent by M. Michelin, is from Le Loile pres

la chaux de fonds Neuchatel.

104 FOREIGN OOLITIC HEMICIDARIS.

HeMicIDARIS ALPINA. Agassiz, Echinoderm. Foss. Suisse, II, p. 52, t. 18, figs. 19—22.

Test large, sub-conoidal. Ambulacra wide, with six pairs of large, close-set semi-
tubercles at the base; two marginal rows of round granules above, and between these
four or five rows of a microscopic miliary granulation. Inter-ambulacra with eight tubercles
in each column. Mouth opening large, peristome deeply notched, lobes nearly equal.
Apical disc of moderate size, elements nearly equal.

Dimensions.—Height, nine tenths of an inch; breadth, one inch and one quarter.

Formation —“ Portlandien moyen (Kimméridgian) de Gesné et des Ormonds (Alpes
Vaudoises), trés rare.” — Desor.

Collections —Museums of Berne and Zurich

Hemicrparis Tuurmanni. Agassiz, Hchinoderm. Foss. Suisse, I, p. 50, t. 19,
figs. 1—3.

Test small, depressed. Ambulacral areas narrow and very flexuous, with small semi-
tubercles at the base, and minute marginal tubercles above. Inter-ambulacral areas wide,
with three or four tubercles only in each row, which have very prominent bosses; the
areolas are each surrounded by a complete circle of scrobicular granules. Mouth opening
large, peristome divided by notches into ten nearly equal-sized lobes.

Dimensions.—Height, eleven twentieths of an inch ; breadth, one inch and one tenth.

Formations.—<“ Portlandien moyen (Marnes Ptérocériennes) du Banné prés Porrentruy,
de Delémont, du Jura Vaudois, des environs de Salins.”—Desor.

Collections.—Museums of Neuchatel and Bale. Coll. Michelin, Thurmann; common.

fumrorparis Hormannt. Syn. Cidarites Hofmanni. Roemer, Oolitic Gebirges, p. 25,
t. 1, age 18:

ia al ° .
lest small, sub-spheroidal, flat at the summit. Ambulacral areas narrow, convex, and
slightly flexuous, with five or six pairs of semi-tubercles at the base, and two rows of small

FOREIGN OOLITIC HEMICIDARIS. 105

marginal granules above. Inter-ambulacral areas with seven tubercles in each row;
areolas confluent. Apical disc prominent, the anterior pair of genital plates the largest.
Mouth opening of moderate width, peristome nearly equal lobed.

Dimensions.—Height, two fifths of an inch; breadth, nineteen twentieths of an inch.

Formations. —* Portlandien moyen, Kimméridgien, du Spielberg (Hanover), de Fritzow
en Pomeranie.” —Desor.

Collections.—Museum Neuchatel. Coll. Roemer, my Cabinet. Sent me by Professor

Roemer.

Hemicriwaris mirra. Agassiz, Echinoderm. Foss. Suisse, II, p. 48, t. 17, figs. 7—9.

Test hemispherical, inflated towards the base. Ambulacra prominent and nearly
straight, semi-tubercles small. Inter-ambulacral tubercles more crowded together than in
Hemicidaris intermedia ; aveolas all confluent. Peristome deeply notched, and nearly

equal lobed.
Dimensions.—Height, seven tenths of an inch ; breadth, one inch.

Formations.—< Portlandien moyen (Calcaire a Tortues) de Saint Nicolas pres Soleure
Ptérocérien de Pierre-Percée (Jura) assez rare.’’— Desor.

Collections —Museum Neuchatel. Coll. Thurmann.

14

106 DIADEMAD &.

Family 3—DiaDEMADZ.

This family includes large and small urchins, with the test thin, circular, pentagonal,
or sub-pentagonal; more or less depressed; mouth opening large, central; peristome
decagonal, and divided into ten lobes by deep notches. |

Apical disc small, directly opposite to the mouth, and composed of five genital,
and five ocular plates; the anterior pair of genital plates are, in general, a little larger
than the posterior pair; and the right antero-lateral plate, with the small, spongy, madre-
poriform body on its surface, is the largest. ‘The vent is round or oblong, and is generally
in the centre of the genital circle.

The ambulacral areas are more or less wide; sometimes they are one half the width
of the inter-ambulacral areas, and furnished with two or four rows of primary tubercles,
often as large and as numerous as those of the inter-ambulacral areas.

The poriferous zones are narrow, and almost always straight ; the pores are unigeminal,
bigeminal, or trigeminal in their disposition in different genera.

The inter-ambulacral areas are, in general, twice the width of the ambulacral; there
are from eight to fourteen plates and upwards in each column; the areas are occupied by
two, four, six, or eight rows of primary tubercles, nearly all of the same size; or there are
rows of primary tubercles, with two or four rows of secondary tubercles, much smaller in
size, filling up the interspaces of the area. The bosses of the tubercles are small, and
their summits are in general crenulated, but sometimes they are uncrenulated; the spmi-
gerous tubercles are small; in general they are perforated, rarely are they imperforate ;
the presence or absence of these characters, added to the structure of the poriferous zones,
attord, when taken collectively, good generic characters.

In general the inter-ambulacral tubercles are larger than the ambulacral, but sometimes
they are of equal sizes in both areas, a character which distinguishes the genera of this
family from those of the Ciparip# and Humicrparipa.

The spines in the living genera are long, slender, and tubular; sometimes they are
thrice the length of the diameter of the shell.* In the fossil genera they rarely attain the
length of the diameter of the shell, and are stout and solid; the slender, tubular spines have
their surface ornamented with oblique annulations of fringe-hke scales; whilst the surface
of the solid fossil spines is covered with fine, longitudinal lines; but neither prickles
nor other asperities are developed on their stems.

Lamarck} subdivided Klein’s genus Cidaris into two sections, the “‘ Zurdans” and the

* Peters, Uber die Gruppe der Diademen, p. 7.
+ ‘Histoire des Animaux sans Vertébres,’ tom. iii, Ist edit., pp. 54—48.

DIADEMAD &. . 107

“ Diadems ;” these Dr. Gray* afterwards converted into two genera, separating from
the Diadems Cidaris radiata, Leske,t as the type of his new genus Astropyga. The
genus Cidarites of Lamarck was considered as a natural family, composed of the genera
Cidaris, Diadema, and Astropyga, which he thus characterised :

Family 1. Crparip#. Cidarites, Lamarck.
Body with two-sized spines; larger ones club-shaped, or very long;
spine-bearing tubercles perforated at the apex.

Genus 1. Crdaris, Klein, Lamarck ; Turbans.

Body depressed, spheroidal, ; ambulacra waved ; small spines compressed,
two edged, two rowed, covering the ambulacra, and surrounding the base
of the larger spines.

This genus may be divided according to the form of the larger spines ;
the extra-ambulacral beads have only two rows of spines.

Cidaris imperialis, Lamk., Klein, t. 7, fig. a.

Genus 2. Diadema. Diadems.
Body orbicular, rather depressed; ambulacra straight, spines often
jistulous.
Echinometra setosa, Rumph., Leske, Klein, t. 37, figs. 1, 2.
Echinus diadema, Linn., Syst. Nat., by ‘Turton, vol. iv, p. 139.
Echinus calamaria, Pallas, Spicil. Zool., t. 2, figs. 4—8.

Genus 3. Astropyga.
Body orbicular, very depressed ; ambulacra straight ; ovarian scales very
long, lanceolate ; beads with several series of spines.
Cidaris radiata, Leske, Klein, t. 44, fig. 1.

The very meager characteristics by which this author has defined the last two genera
only show that a difference exists, but his description is insufficient for a correct diagnosis
between them; hence various opinions exist regarding the characters and limits of the
genus Diadema ; and only one of the species enumerated as types, the Dzadema setosa,
Rumph., is admitted to be a true Diadem. The valuable memoir of Herr W. Peterst
has removed some of the difficulties that surrounded this subject, and his grouping of the
living Diadems makes an important step towards a natural classification of one section of

* «Annals of Philosophy,’ new series, vol. x, p. 426, 1825. ‘An attempt to divide the Echinide or
Sea Eggs into Natural Families.”

+ Leske apud Klein, ‘Naturalis Dispositio Echinodermatum,’ t. 44, fig. 1, p. 116.

t Uber die Gruppe der Diademen, ‘Gelesen in der Konigl. Akademie der Wissenschaften,’ Berlin,
Aug. 1853.

108 DIADEMAD 4s.

this family. Although the present state of our scientific knowledge of the Diademade
may be considered as transitional rather than positive, still we know enough to justify the
separation of the fossil Diadems from the existing genera, as proposed by M. Desor.*

The Diademade, in fact, appear to consist of two types: one of these, with a few rare
exceptions, appertains to the present epoch; the other existed during the deposition of the
secondary and tertiary rocks. The living forms are in general large, depressed urchins,
with a thin shell, havmg the tubercles and pores variously arranged in the different genera.
‘They have, in general, very long, slender, twéw/ar spines, the surface of which is covered
with oblique annulations of small imbricated scales. The fossil species, on the contrary,
are sinaller urchins, having a thicker test; the tubercles and pores are variously disposed in
the different genera; the spines rarely attain the length of the diameter of the test; they
are solid, in general cylindrical, sometimes flattened or awl-shaped, and their surface is
covered with fine longitudinal lines.

I propose to include the following genera im this natural family :

A Table showing the classification of the Diademade.

fe Section a.

Spines very long, slender, tubular, covered with | DiaDEMa, Gray.
Savienya, Desor.
AsTRopyGa, Gray.

EcuInoturix, Peters.

oblique annulations of imbricated scales. Living in

tropical seas.
A few annulated tubular spines are found in the

DIADEMADA.. Upper Chalk and in the Coralline Crag.

Spines short, slender, solid; surface covered with CyPHosoMA, Agassiz.

fine longitudinal lines. Hemipepina, Wright.
PEpiINa, Agassiz.

ECHINOPSIS, Agassiz.

Extinct in the Oolitic, Cretaceous, and Tertiary

rocks.

Section B. PsEUDODIADEMA, Desor.

PsnupopiaDEMa,t Desor. 1854.

This genus is composed of small urchins, with a moderately thick test, which rarely
attains two inches in diameter; the ambulacral areas are in general one third, or even one
half the width of the inter-ambulacra; the primary tubercles of both areas are all perforated,
and nearly of the same size; their bosses are small, with sharply crenulated summits.

The ambulacral areas have two rows of tubercles; the inter-ambulacral areas have two
rows only, or two rows of primary, and two or four shorter rows of small secondary

* «Synopsis des Hchinides Fossiles.’

- The IpP1fiE © a O1TA . . . * A .
f The specific name given by Lamarck to the fossil urchin described as Cidurifes pseudodiadema.

PSEUDODIADEMA. 109

tubercles ; or they have four, or even six rows of nearly equal-sized primary tubercles at
the equator.

‘The poriferous zones are narrow and straight ; the pores in oue section are unigeminal
throughout ; but in another section they are bigeminal in the upper part of the zones.

The apical disc is seldom preserved; it is, in general, small; and the anterior pair of
genital plates are larger than the posterior pair.

The mouth opening is large, the peristome is deeply notched, and the oral lobes are
not very unequal sized.

The spines rarely attain the length of the diameter of the shell; they are in general
much shorter, and are cylindrical or needle-shaped, and have a prominent, milled ring near
the articulating head; the rim of the acetabulum is crenulated, and the socket perforated ;
the surface of the stem is sculptured with delicate longitudinal lines.

The Pseudodiadema are all extinct, and are found in the Liassic, Oolitic, Cretaceous,
and Tertiary rocks.

Pseudodiadema differs from Diadema in having solid spines, with a smooth
surface, the sculpture, in most cases, consisting of microscopic, longitudinal lines; whilst
the spines of Deadema are tubular, and have oblique annulations of scaly fringes on their
surface. It differs from Cyphosoma, which is a Cretaceous genus, in having the tubercles
always perforated, those of Cyphosoma being imperforate.

It differs from Hemipedina in having a small apical disc, and tubercles with crenulated
bosses, those of Hemipedina beg smooth; and from Pedina in having the pores
unigeminal or bigeminal, those of Pedina being arranged in triple, oblique pairs.

The Pseudodiademas may be divided into two sections, from the different manner the
pores are arranged in the zones. In one group the pairs of pores are not so numerous,
and they are disposed im a single file throughout ; in another group the pores are more
numerous, and crowded together in the upper part of the zones. Professor M‘Coy* has
proposed the genus Dip/opodia for this group. Ceterus paribus, the crowding together
of a greater number of pores in a zone is, at most, a sectional, and can never form -a
stable generic character, inasmuch as it is subject to great variation in the diplopodous
species themselves, and is, moreover, often only an adult development.

* © Annals and Magazine of Natnral History,’ 2d series, vol. ii, p. 412.

110 PSEUDODIADEMA.

The following Table exhibits these Sections, and shows at the same time the arrangement of
the tubercles in the unigeminal and bigeminal groups.

Section a.—Pores unigeminal in the upper part of the zones :
Examples.

a. Two rows of primary tubercles only
in the inter-ambulacral areas

6. 'T'wo or four rows of primary tuber-
cles, and two or four rows of
smaller secondary tubercles in the
inter-ambulacral areas

Peeudodiadema depressum.
Pseudodiadema hemisphericum.

Section B.—Pores bigeminal in the upper part of the zones :

a. Two rows of primary tubercles, and
two rows of small secondary
tubercles, in the inter-ambulacral
areas

Pseudodiadema versipora.

6. Four rows of primary tubercles in

\ Preudodiadema variolare.
the inter-ambulacral areas

A. Species from the Inas.
PsxupopraDuMA Moorrn, Wright. Pl. VI, fig. 1 a, 4, ¢, d.

Dirapema Moorett. Wright, Annals and Magazine of Natural History, 1854, 2d series,
vol. xii, p. 171, pl. 12, fig. 3.
— — Morris, British Fossils 2d edit., 1854. Note on additional species
of Echinodermata.
DiapEemopsis Moorrtt. Desor, Synopsis des Hchinides Fossiles, p. 81.

Test circular, depressed ; ambulacral tubercles smaller than those of the inter-ambu-
lacral areas; plates of the test covered with a small, wide-set, prominent granulation ;
mouth large and decagonal; anal opening large; apical disc of moderate size.

Dimensions.—Height, one fourth of an inch; transverse diameter, six tenths of an
inch.

Description —Vhere is much difficulty in distinguishing some of the smaller Diademas
from each other, imasmuch as the young condition of many of the larger species so closely
resembles the adult state of others, that it is only after obtaining a number of individuals
of different species in the various phases of their growth, that the naturalist feels himself

FROM THE LIAS. 111

upon sure ground when endeavouring to distinguish the affinities and differences existing
among them. After a diligent search for urchins in the Lias of Gloucestershire, I have
succeeded in collecting from these rocks only a very few examples of this group. In addi-
tion to those found near Cheltenham, my friend Mr. Moore, of Bath, kindly presented me
with a few specimens which he collected from the Upper Lias near Ilminster, and from
these collective materials the species under consideration was discovered.

Pseudodiadema Moorew has a circular outline, slightly inclining to a pentagonal contour ;
it is much depressed at the upper surface, and is flattened at the base (fig. 1 a). ‘The ambu-
lacral areas are very narrow, being less than one third the width of the inter-ambulacral
(fig. 1 4); their margins are occupied by two rows of tubercles, about eight in each row
(fig. 1 d), which, at the base, and up to the equator, are nearly as large as those of the
inter-ambulacra, but from that region to the apex of the area they rapidly diminish in size,
and are here very disproportionate in magnitude to them ; a zigzag line of single granulation
separates the two rows of tubercles from each other (fig. 1 d@). ‘The inter-ambulacral
areas are wide and well developed (fig. 1 4, c), from eight to nine in each row, which
occupy the centre of the plates (fig. 1 a); the areolas of the tubercles on the upper surface
are surrounded with a circle of granules which separates them from each other (fig. 1 ¢),
but those of the base are confluent above and below (fig. 1 c). The miliary zone at the
base of the test has a number of granules scattered over it (fig. 1 e) ; whilst on the upper
surface the plates are destitute of any other ornament beyond the faint circles that
surround the tubercles (fig. 1 4).

The poriferous zones are narrow, the pores are strictly unigeminal (fig. 1 4, d); the
avenues are, however, rather flexuous below ; the basal tubercles of both areas are nearly
alike in size, but on the dorsal surface those of the ambulacra dwindle into large granules ;
whilst those of the inter-ambulacra maintain their size up to the last pair, which are small
near the margin of the disc. The mouth opening is large (fig. 1 e), and the peristome is
divided into ten nearly equal-sized lobes. |

The apical disc is partly preserved in the specimen here figured (fig. 1 4). It consists
of five large ovarial plates, of a heptagonal form; two of the sides unite with the inter-
ambulacral plates, two with the ocular, two with the adjoining ovarials, and the single
surface contributes to form the boundary of the anal opening, which is of moderate size ;
the five ocular plates are small and heart-shaped ; their apex is directed towards the anal
opening, and their base to the area; the madreporiform tubercle is slightly elevated on the
right antero-lateral ovarial plate; the surface of all the discal elements is almost destitute
of sculpture or granulation.

Afinities and differences—Pseudodiadema Mooreii resembles Pseudodiadema depres-
sum, Agassiz, in the depression of its upper surface and the flatness of its base, likewise
in having the tubercles of both areas nearly of a uniform size below; but it is
readily distinguished from Psewdodiadema depressum by the number and greater develop-

112 PSEUDODIADEMA.

ment: of the tubercles of the ambulacra, which maintain their size throughout, whilst in
Pseudodiadema Mooreti the ambulacral tubercles are fewer in number, and more rudi-
mentary in size, in all the upper part of the areas. The contour of the test, moreover, does
not assume the pentagonal outline of Psewdodiadema depressum, nor has the upper surface
of the inter-ambulacral areas the median depression seen on the test of the latter. The
mouth opening is larger, and the decagonal lobes are more equal in size in Pseudo-
diadema Mooreti than in Pseudodiadema depressum.

Locality and Stratigraphical position.—l have collected Pseudodiadema Moore in
the Upper Lias of Gloucestershire. Mr. Moore found it in the same stratum near
Ilminster, with Ammonites communis, Sow., and Ammonites serpentinus, Schloth. Prof.
Deslongchamps has communicated a specimen of this urchin, which he found in the Lias
supérieur de May, Calvados, associated with Leptena Davidsoni, Deslong., Thecidium
Bouchard, Davidson, and several other species of Upper Lias Mollusca.

I dedicate this species to Mr. Charles Moore, of Bath, whose assiduous practical
researches in palzontology have brought to light so many interesting forms from the
Middle and Upper Lias beds of Somersetshire.

B. Species from the Inferior Oolite.

PsEUDODIADEMA DEPRESSUM, Agassiz. PI. VI, fig. 2 a, b,¢, d,e, fg, h.

DIADEMA DEPRESSUM. Agassiz and Desor, Catalogue raisonné des Echinides,
Annales des Sciences Naturelles, tom. vi, p. 349, 3™° série.
— — Cotteau, Htudes sur Echinides Fossiles, pl. 2, p. 43.
— — D’Orbigny, Prodrome de Paléontologie, tome i, p. 290,
No. 512.
— — Morris, British Fossils, 2d edit., 1854, p. 76.
— — Wright, Annals and Magazine of Natural History, 2d ser.,
vol. vill, p. 258, pl. 12, fig. 2 a, 6, ¢, d.
PsEUDODIADEMA DEPRESSUM. Desor, Synopsis des Echinides Fossiles, p- 65.

Test pentagonal, depressed ; ambulacral areas convex and prominent ; inter-ambulacral
areas flattened; two rows of nearly equal-sized primary tubercles in both areas; no
secondary tubercles; mouth large and decagonal ; peristome nearly equally lobed.

Dimensions.—Height, eleven twentieths of an imch; breadth, one inch and three
tenths.

Description.—The ambulacral areas of this urchin are rather more than one half the
breadth of the inter-ambulacral areas, and have from ten to twelve pairs of well-developed
primary tubercles, separated by a zigzag line of small granulations (fig. 2 d). The inter-

FROM THE INFERIOR OOLITE. 113

ambulacral areas are nearly of a uniform breadth throughout ; there are about ten pairs of
tubercles in each area. In consequence of these segments of the test being double the
width of the ambulacra, the tubercles stand more apart (fig. 2 d). The tubercles of both
areas are nearly uniform in size; those of the ambulacra are the smallest; they have a
smooth base, with a finely crenulated summit, and are perforated (fig. 2 2); there are no
secondary tubercles, but the miliary zones are covered with small granulations, which are
closely set together on the surface of the plates; three or four of these at the base
are perforated (fig. 2g). The mammillary eminences of both areas are surrounded by
smooth areolas, which are nearly all confluent (fig. 2 7). The ambulacral areas become
rapidly contracted towards the vertex (fig. 2 a), whilst the inter-ambulacral maintain their
breadth, so that the space between the rows of primary tubercles is very uniform in
width throughout (fig. 2 a, e). The miliary zones, with the exception of the internal
border of the four superior inter-ambulacral plates, are covered with small, close-set
granulations of different sizes (fig. 2d), which form semicircles around the areolas, and
zigzag lines down the centre of the areas. ‘The pores consist of from thirty-six to forty
pairs in each avenue, super-imposed in a single file; about four pairs of pores are opposite
each large inter-ambulacral plate (fig. 2 d); im the wide space of the avenues around
the mouth, they form rows of triple oblique pairs (fig. 2g). The mouth is large and
decagonal (fig. 2 4); the notches of the peristome divide the opening into ten nearly equal-
sized lobes, the borders of the notches are reflexed at the angles; the apical disc is unknown;
the spines are small, subulate, and delicately striated longitudinally (fig. 2 e, fF 2).

Affinities and differences.—TVhis urchin resembles Pseudodiadema equale, Agassiz, but
differs from it in the absence of secondary tubercles in the inter-ambulacral areas ; by its
pentagonal form it resembles Pseudodiadema versipora Phillips, but is distinguished from
that species in having the pores arranged in a single file; whereas in Pseudodiadema
versipora, from the equator to the apical disc, the pores fall into double rows. The
tubercles are likewise smaller, and more deeply perforated ; it belongs, moreover, to a lower
zone of the Oolitic group, Pseudodiadema versipora being a characteristic urchin of the
Coral Rag of England and the “Terrains 4 Chailles” of Switzerland.* Like Pseudo-
diadema versipora, Pseudodiadema depressum possesses a pentagonal form, a peculiarity
depending on the prominence of the ambulacral areas, and common to several species of
this genus.

Locality and Stratigraphical position —This urchin is common in the lower ferruginous
beds of the Inferior Oolite, the Pea Grit, at Crickley, Leckhampton, and Dundry Hills.
T have collected it from the Great Oolite at Minchinhampton, and from the Bradford Clay
at Tetbury-road Station. ‘The Inferior Oolite specimens are in general much crushed ;

* Agassiz, ‘Echinodermes Fossiles de la Suisse.’

15

114 PSEUDODIADEMA.

the apical disc is always broken, but the spines are sometimes adherent to the test (fig. 2 2).
It has been collected by M. d’Orbigny in the Inferior Oolite of Saint Honorine, Ranville,
where it is abundant. I have before me a specimen collected from the “ Oolite Ferru-
gineuse de Bayeux ”’ so closely resembling some of those from Crickley Hill, that it might
readily be taken for an urchin from that locality. My friend M. Deslongchamps, who has
kindly lent me this specimen for comparison, observes, “‘ seul exemplaire que j’ai trouve ;”
so that it must be rare im Normandy. It has been obtained by M. Cotteau from the
Ferruginous Oolite, of ‘‘ Tour-du-Pré, prés Avallon, département de ’Yonne,” which bed
lies upon the Calcaire a Entroques, the true equivalent of the Dundry, Cotteswold, and
Dorsetshire beds of the Inferior Oolite.

2

HHistory.—Pseudodiadema depressum was first mentioned in the ‘ Catalogue raisonné
des Hchinides’ by Agassiz and Desor, but was neither figured nor described by
them. This, however, has been done by M. Cotteau, in his ‘Etudes sur les Hchinides
Fossiles. In both countries it appears to characterise beds belonging to the same
geological horizon.

C. Species from the Stonesfield Slate.
PsEUDODIADEMA Parxinsoni, Desor. Pl. VI, fig. 4.

PSEUDODIADEMA PARKINSONI. Desor, Synopsis des Hchinides Fossiles, p. 66.
Parkinson’s Organic Remains, vol. iii, pl. 1, fig. 8, not named
in this work.

Test small, circular, depressed ; ambulacral areas wide; tubercles of the inter-ambu-
lacral areas a little larger than those of the ambulacral; no secondary tubercles; spmes
thick, subulate, and a little bent, nearly as long as the diameter of the test, surface covered
with longitudinal lines.

Dimensions.—Transverse diameter, three fifths of an inch; height unknown.

Description.—This pretty little Diadem has been overlooked by all English authors
except Parkinson, who figured it in his ‘Organic Remains,’ and only observes (vol. iii,
p. 10), “This very uncommonly perfect specimen from Stunsfield, Oxfordshire (Pl. I,
fig. 8), in which a considerable number of spines are still adherent to the shell, appears to
be of the same species with the last fossil” (a Wiltshire Psewdodiadema). M. Desor, in
his ‘Synopsis,’ names this species Parkinsonz, and adds the following note: ‘“ Je ne connais
cette espéce que par la jolie figure qu’en adonnée Parkinson. II est surprenant qu’aucun
des auteurs Anglais ne ait encore mentionnée, ni ne lui donné un nom. Parkinson s’est
borné a la figurer sans lui imposer un nom.”

FROM THE STONESFIELD SLATE. 115

When collecting materials for my ‘ Memoir on the Cidaride,’ this species engaged my
attention, and I endeavoured, in vain, to find the original of Parkinson’s figure, as I was
under the impression that it was a juvenile form of Pseudodiadema versipora, from the
Coral Rag of Wiltshire, very much resembling a specimen in the cabinet of Mr. Mackniel,
of Trowbridge; for this reason it was not included in my ‘ Memoir.’ As M. Desor has
now, however, named the specimen, and entered it in his ‘Synopsis, I have considered
it desirable to have an accurate copy of Parkinson’s figure transferred to my work.

The ambulacral areas are moderately wide, and carry two rows of tubercles nearly as
large as those of the mter-ambulacral areas; the pores are arranged in a single file
throughout; the inter-ambulacral areas are about once and a half as wide as the
ambulacral, and have two rows of primary tubercles; nor is there any evidence of the
existence of a secondary range; the spines are thick and subulate, slightly bent in the
middle, and marked with longitudinal lines; they are nearly as long as the diameter of
the shell and are very robust in proportion to its dimensions.

Affinities and differences.—TVhis species resembles Pseudodiadema depressum in the
absence of secondary tubercles; but that species is distinguished from it by the test being
more circular, and its spmes being thicker and bent. It may, however, be a juvenile
form of Pseudodiadema versipora, from the Coral Rag, the artist having overlooked the
crowding together and doubling of the pairs of pores in the upper part of the poriferous
zones ; not having the advantage of examining the specimen, I make these remarks with
much hesitation, well knowing from experience how readily we may be deceived by figures,
where no details are added, to indicate the specialities of the organism.

Locality and Stratigraphical position.—Myr. Parkinson says it was collected from the
Stonesfield Slate at Stonesfield, Oxon, where it must be exceedingly rare. I have collected
fragments of a small Pseudodiadema from the Yellow Clays of the Stonesfield Slate at
Sevenhampton, Gloucestershire, which may belong to this species. My specimens are
mislaid, but they were not in a good state of conservation.

D. Species from the Great Oolite.
PsEUDODIADEMA PENTAGONUM, J/‘Coy. Pl. VI, fig. 3 a, 4, ¢, d.

DipLopopia PeNTAGONA. M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. 11, p. 412.
DiaDEMA PENTAGONUM. Morris, Catalogue of British Fossils, 2d edition, 1854, p. 77.
= — Woodward, Memoirs of the Geological Survey, Decade V. Notes
on Brit. Foss. Diademas.

Test small, pentagonal, depressed ; ambulacral areas with two marginal rows of primary

116 PSEUDODIADEMA.

tubercles nearly as large as those of the inter-ambulacra; poriferous zones wide; pores
unigeminal at the equator, bigeminal on the upper and under parts of the zones; inter-
ambulacral areas thrice the width of the ambulacral, with two rows of primary tubercles,
and a short row of secondary tubercles, one third the size of the primaries, between the
peristome and equator, situated between the zones and the primary row.

Dimensions —Height, three tenths of an inch; transverse diameter, seventeen
twentieths of an inch.

Description.—This pretty little urchin is said by Professor M‘Coy, who first described
it, to be not uncommon in the Great Oolite of Minchinhampton, but experience has taught
me that it is a very rare form in the rich shelly beds of that remarkable locality.

The test is moderately thick, and much depressed (Pl. VI, fig. 3 a, 6); it is distinctly
pentagonal, from the prominence of the ambulacra, and in its general facies very much
resembles Pseudodiadema depressum ; but the structure of the poriferous zones, and the
crowding together of the pores in the zones, shows it to be very distinct from that
Inferior Oolite form. It belongs, in fact, to that section of the genus Pseuwdodiadema
which has the pores bigeminal in the upper part of the zones (Pl. VI, fig. 3 c), a structure
which Professor M‘Coy thought of generic value, and proposed the genus Diplopodia* for
the reception of these bigeminal Diadems, describing the species now under consideration
as a type of the same.

The ambulacral areas are narrow and prominent, with two rows of from twelve to
fourteen primary tubercles, nearly as large as those of the inter-ambulacral areas (fig. 3 d) ;
a few miliary granules separate the tubercles in the middle of the areas, but they disappear
in their upper and lower parts, in consequence of the close approximation of the tubercles
in these portions of the area (fig. 3 4, ©).

The poriferous zones are wide, especially above and below ; near the equator there are
five or six pairs of pores, which are unigeminal (fig. 3 4); but above these the pairs of
pores are bigeminal, each pair bemg separated by a diagonal line, formed by an elevation
of the surface of the zonal plates (fig. 3 ¢) ; between the unigeminal portion of the zones
and the peristome the pores are rather irregularly bigeminal, they then fall into triple,
oblique pairs near the mouth; the upper part of the zones consists of small pyriform plates
(Pl. VI, fig. 3 c, d), which are neatly dovetailed together, the line of union being marked
by diagonal lines of elevation (fig. 3 d).

The inter-ambulacral areas are three times the width of the ambulacral; they have two
rows of primary tubercles, from ten to twelve in each row, situated on the centre of the
plates; they are about the same size as the ambulacral tubercles at the equator, but are
much larger in proportion in the upper part of the area (fig. 3 d); the bosses are small,

* ©Annals and Magazine of Natural History,’ 2d series, vol. ii, p. 412.

FROM THE GREAT OOLITE. 117

having their summits feebly crenulated, and the tubercles not deeply perforated. ‘The
areolas are superficial, and confluent above and below (fig. 3 d); five or six granules
form semicircles on each side of the areola. The miliary zone, which is of moderate
width, contains few granules besides those forming the scrobicular semicircles, in the upper
part of the test this space is almost naked; between the peristome and the equator there
are five or six secondary tubercles, about one third the size of the primaries, situated between
them and the poriferous zones, forming a short, irregular row, which scarcely reaches the
middle of the test (fig. 3 4).

The mouth opening in width is nearly one half the diameter of the test; the peristome
is unequally decagonal, the ambulacral being larger than the inter-ambulacral lobes.

The disc opening is large, and nearly circular; but the disc is absent in all the speci-
mens I have examined, and in none of them are the spines preserved.

Afinities and differences.— Pseudodiadema pentagonum very much resembles Pseudo-
diadema depressum in its pentagonal and depressed form, in having the primary tubercles
of both areas at the equator nearly of equal size, and in having the upper part of the
miliary zones almost naked; but it is distinguished from that species in having a short
row of secondary tubercles at the base, between the inter-ambulacral primary tubercles
and the poriferous zones ; in having the poriferous zones wide, and the pores bigeminal in
all the upper portion of the zones, a character which is at once evident and distinctive
between these two nearly allied forms. Pseudodiadema pentagonum resembles Pseudo-
diadema versipora in its depressed and pentagonal form, and in the bigeminal character
of the pores in the upper parts of the zones; but it is distinguished from that beautiful
Coral Rag urchin in having much smaller primary tubercles, and fewer and larger granules
in the miliary zones; the central and lateral zones of the inter-ambulacra in Pseudodiadema
versipora bemg much wider, and filled with several rows of small, close-set granules ;
whereas in Pseudodiadema pentagonum there are few granules besides those forming the
scrobicular semicircles. The diplopodous character of this species serves to distinguish it
from all other British Oolitic Diadems.

Locality and Stratigraphical position.—This beautiful urchin has been found in the
shelly beds of the Great Oolite at Minchinhampton, where it is very rare. Associated
with it are the following Echinoderms: Acrosalenia hemicidaroides, Wright ; Polycyphus
nodulosus, Minster; Pygaster semisulcatus, Phillips; Hyboclypus agariciformis, Forbes ;
LEchinobrissus clunicularis, Lihwyd.

LMistory.—First described by Professor M‘Coy in the ‘ Annals of Natural History,’*
m his paper ‘On some new Mesozoic Radiata,’ under the name Diplopodia pentagona,
and regarded by him as the type of a new genus of Diapemaps#, which he supposed was

* © Annals and Magazine of Natural History,’ 2d series, vol. ii, p. 412.

118 PSEUDODIADEMA.

limited to the Oolites; but it has been ascertained that the same diplopodous structure of
the poriferous zones is found to prevail likewise in several Cretaceous species, as well as in
those cited by this author. Neither Prof. Agassiz nor the late Prof. Edward Forbes
considered the diplopodous character of the poriferous zones alone of generic importance ;
but Professor M‘Coy and M. Desor think otherwise, the latter author having retained the
genus Diplopodia in his ‘Synopsis des Echinides Fossiles.’ I am indebted to Professor
Sedgwick for the loan of the type specimen belonging to the Cambridge Museum, which
is now figured (Pl. VI, fig. 3 a, 6) for the first time.

PsEUDODIADEMA HOMostTiema, Agassiz. PI. VI, fig. 5 a, 6, ¢, d, e, f.

DIADEMA HOMOSTIGMA. Echinodermes Fossiles de la Suisse, part ui, t. 17, figs. 1—5,
p. 24.
— - Agassiz and Desor, Catalogue raisonné Echinides, Annales
des Sciences Naturelles, 3° série, tome vi, p. 347.
— MQUALE. Quenstedt, Petrefactenkunde, t. 49, fig. 29, p. 579?
PsEUDODIADEMA HOoMOsTIGMA. Desor, Synopsis des Echinides Fossiles, p. 65.
DIADEMA HOMOSTIGMA. Woodward, Memoirs of the Geological Survey, Decade V,
Notes on British Fossil Diademas.

Test small, depressed, nearly circular; ambulacral areas nearly as wide as the inter-
ambulacral; primary tubercles in both, nearly of the same size; no secondary tubercles ;
poriferous zones unigeminal; mouth opening large, peristome unequally decagonal.

Dimensions.—Height, one fifth of an ich; transverse diameter, half an inch.

Description.—This beautiful little species was first discovered by M. Nicolet in the
Inferior Oolite of Chaux-de-Fonds, and figured and described by M. Agassiz in his
‘Hchmodermes Fossiles de la Suisse, who, in describing it, observes, ‘the species which
I have figured under this name offers none of those prominent traits which we recognise
in so many species. It also presents a uniformity almost hopeless for description. Up to
the present (1840) I only know the specimen I have figured, which is all the more valuable
on account of the rock (Inferior Oolite) from whence it was collected, for we know in what
a bad state of preservation the most of the fossils of this terrain are found in.” It is
probable that the small Diadema equale, figured by Quenstedt from the Brown Jura 8
of Spaichingen, is identical with Pseudodiadema homostigma, as it has been collected
from the same geological horizon, and wants the rows of secondary tubercles, which
characterise that Coral Rag form.

The ambulacral areas are nearly as wide as the inter-ambulacral areas, and support

FROM THE GREAT OOLITE. 119

two rows of primary tubercles, eight to nine tubercles in each row; those at the equator
are nearly as large as the tubercles in the inter-ambulacra in the same region of the test
(fig. 5 d); the summits of the bosses are sharply crenulated, and the tubercles are small
and perforated ; a zigzag row of small granules extends down the middle of the area
(fig. 5 e), and small transverse branches shoot out from the sides, and extend to the
poriferous zones, separating the bosses from each other, and forming imperfect areolar
circles around them.

The poriferous zones are narrow, and the pores are unigeminal throughout (fig. 5 ¢);
the zones approach each other very closely in the upper part of the test (fig. 5 4), which
gives to the inter-ambulacra the uniform width they have (fig. 5 4, @).

The mter-ambulacral areas are a very little wider at the equator than the ambulacral
(fig. 5 e); from the equator upwards they maintain a very uniform width (fig. 5 6) ;
there are nine tubercles in each of the two rows, which are set on small bosses, with
sharply crenulated summits; the tubercles are prominent and perforated (fig. 5 /); the areolas
are confluent above and below (fig. 5 4); between the tubercles and the poriferous zones a
row of unequal-sized granules extends (fig. 5 e), which forms one side of the scrobicular
circle; the miliary zone is narrow, consisting, from the peristome to the equator, of two
rows of granules, from the equator upwards a few more granules are interspersed with
them, these form the other portion of the scrobicular circle (fig. 5 e); the upper part of
the zone is naked in the region of the central suture (fig. 5 4).

The mouth opening is large, the peristome is unequally decagonal (fig. 5 c), the ambu-
lacral lobes being the largest. The base of the test (fig. 5 c) shows how uniform the
structure of this Psewdodiadema is; and the uniformity im the size of the tubercles in this
region gives value to its specific name, homostigma.

The discal opening is small, and nearly circular ; but the plates of the disc are absent.

Afinities and differences—This species is distinguished from the smaller forms of
Pseudodiadema depressum in being nearly circular, in having wider ambulacra, a smaller
discal opening, and more equal-sized tubercles. It has many affinities with Psewdodiadema
Bailyi (Pl. VI, fig. 1); but is distinguished from it in having proportionately wider
ambulacra, the primary tubercles likewise are of a more uniform size throughout the area,
those of Pseudodiadema Baily: diminishing more rapidly in the upper part of this region.

Locality and Stratigraphical position.—I have collected this species in the Bradford
Clay, near the Tetbury-road Station of the Great Western Railway, and Mr. Wiliam Buy
has collected it in the Cornbrash near Sutton-Benger, Wilts. It is rather a rare form in
these beds. My excellent friend, the Rev. W. Griesbach, has kindly sent me a specimen
which he found in the marly beds of the Great Oolite at Wollaston, Northamptonshire,
associated with several Great Oolite and Cornbrash species of Echinodermata.

120 PSEUDODIADEMA.

E. Species from the Cornbrash.

PsrvpoprapEma Battyi, Wright, nov. sp. Pl. VII, fig. 1 a, 4, ¢, d, e, fy 9.

Test sub-pentagonal, depressed ; ambulacral areas narrow, a little more than half the
width of the inter-ambulacral, with two rows of primary tubercles, smaller than those of the
inter-ambulacra ; inter-ambulacral areas with two rows of primary tubercles, which
suddenly diminish in size above the equator; poriferous zones narrow, and unigeminal
throughout ; mouth opening large, peristome nearly equally decagonal.

Dimensions.—Height, three tenths of an inch; transverse diameter, seven tenths of an
inch.

Description.—This beautiful little Diadem, hike the preceding species, presents such a
uniformity of structure, and such a total absence of prominent characters, that it is
extremely difficult to form an accurate diagnosis of its specific form.

The test is small, depressed, and sub-pentagonal (fig. 1 a, 6); the ambulacral areas are
prominent, and rather more than half the width of the inter-ambulacral ; they support two
rows of primary tubercles, rather smaller than the inter-ambulacral tubercles, of which
there are eight in each row; a central, zigzag line of granules separates the two rows of
tubercles from each other (fig. 17), and short, transverse, granular branches separate the
areolas of the larger equatorial tubercles; on the upper part of the areas the tubercles
become very small; the poriferous zones are straight and narrow (fig. 1 e), and the pores
are strictly unigeminal throughout (fig. 1 7); there are five pairs of pores opposite one of
the larger inter-ambulacral plates, and from three to four pairs opposite the ambulacral
plates (fig. 1 /).

The inter-ambulacral areas are nearly twice the width of the ambulacral; they are
occupied by two rows of primary tubercles, there being eight tubercles in each row; from
the peristome to the equator the tubercles gradually increase in size (fig. 1d), but above
the equator they diminish rather suddenly in magnitude (fig. 1 ¢), so that the tubercles on
the upper parts of the areas are small in proportion to those at the equator and base of
the test (fig. 1 d); the areolas are wide; the bosses are large, conical, and prominent
(fig. 1 d, f, g); they are confluent above and below, but laterally they are bounded by
semicircles of granules (fig. 1 g), five or six granules, with a few other microscopic ones,
forming incomplete scrobicular semicircles around their sides; the miliary zone is narrow,
and formed only by the granules just described; on the upper part of the area the
eranules almost entirely disappear, and the surface of the plates is naked near the point
where they approach the disc (fig. 1 e); the summit of the conical bosses is crenulated
(fig. 1 y), and the tubercle is small and perforated (fig. 17). There are no secondary
tubercles at the base of this species.

FROM THE CORNBRASH. 121

The base is flat (fig. 1 4); the mouth opening is large (fig. 14d); the peristome is
deeply notched, and the shuld of the test sharply everted (fig.1 d); the ambulacral are
rather larger than the inter-ambulacral lobes ; the margins of the latter have two pointed
processes at the angles of the notches.

The disc opening is large (fig. 1 a, e) ; but as the margin is fractured, its true diameter
cannot be accurately ascertained.

Affinities and differences.—This species has so many affinities with Pseudodiadema
homostigma, that at one time I regarded it only as a large pentagonal variety of that
species; the narrowness of the ambulacra, however (these areas bemg a little more than
half the width of the inter-ambulacra, whilst those of Psewdodiadema homostigma are
nearly as wide as the inter-ambulacra), added to the sudden diminution in the size of
the tubercles in the upper part of the areas, and the greater prominence of all the
bosses, induced me to separate it from Pseudodiadema homostigma.

Locality and Stratigraphical position —This species was collected by Mr. William Buy,
from the Cornbrash near Sutton, Wilts, associated with Acrosalenia hemicidaroides,
Wright; Acrosalenia spinosa, Agassiz; and Lechinobrissus clunicularis, Lihwyd. I have
dedicated this species to Mr. W. H. Baily, whose crayon has so accurately delineated
many of the forms figured in this Monograph.

PsgupopiapEMA Baxurtaz, Woodward. PI. VII, fig. 2 a, 6, ¢.

Drapema Bakreri#. Woodward, Memoirs of the Geological Survey, Decade V. Notes on
British Fossil Diademas.

Test sub-pentagonal, depressed ; ambulacral areas narrow, with two rows of primary
tubercles, about thirteen in each row; poriferous zones narrow, pores unigeminal, near the
mouth trigeminal; inter-ambulacral areas wide, with two rows of primary tubercles, larger
than the ambulacral, about thirteen in each row; bosses not prominent, summits slightly
crenulated ; tubercles small, flat, and finely perforated; miliary zone wide, and sparingly

granulated.

Dimensions.—Height, eleven tenths of an inch; transverse diameter, one inch and

four tenths of an inch.

Description.—The specimen, unfortunately, is not in good preservation, having been
much weathered and bouldered (fig. 2 a, 4). ‘The ambulacral areas are narrow and
16

122 PSEUDODIADEMA

straight, with two rows of small primary tubercles (fig. 2 ¢), about thirteen in each row ;
their bosses are small, and set closely together; a zig-zag central line of granules descends
between the rows, and a few scattered granules separate the areolas above and below from
each other.

The poriferous zones are straight and narrow, the pores are unigeminal and contiguous,
and the pairs of pores are obliquely inclined (fig. 2 c); three pairs of holes are opposite
one ambulacral plate, and five pairs are opposite one inter-ambulacral plate (fig. 2 c); near
the peristome the pores fall into triple oblique pairs. |

The inter-ambulacral areas are rather more than twice and a half as wide as the
ambulacral; they have two rows of primary tubercles, with thirteen in each row; they
are considerably larger than those of the ambulacral areas ; their bosses have a broad base,
but their summits are not deeply crenulated (fig. 2 c); the spinigerous tubercles are small,
flat, and minutely perforated; the central miliary zone is wide, but sparingly granulated
in the middle, and almost naked above; on each plate (fig. 2 ¢) two rows of granules form
a lateral zone, separating the tubercles from the poriferous avenues, and two rows of
granules form one half of the central zone ; in the upper part of the area the areolas are
separated by transverse rows of granules, which, with the lateral rows, form three fourths
of a scrobicular circle. The weathered condition of the specimen renders a more minute
description of the test impossible.

The mouth opening measures eleven twentieths of an inch, that of the diameter of
the test being.one inch and four tenths ; the peristome is deeply notched, and unequally
lobed, the inter-ambulacral being one third less than the ambulacral lobes.

The disc opening is four tenths of an inch in diameter, but the plates are absent.

Afinities and differences.—YVhis species very much resembles the larger specimens of
Pseudodiadema depressum, but the ambulacral tubercles appear to be proportionately
smaller, and the ambulacral areas narrower than in that species; the bosses, likewise, are
not so prominent, and the spinigerous tubercles are smaller; but from the weathered
condition of the specimen, the only one known, it is impossible to make a more accurate
comparison between these two nearly allied forms.

Locality and Stratigraphical position—This urchin was collected from the Cornbrash
at Caistor, Northamptonshire, by the late Miss Baker, and belongs to the British Museum
Collection. It has been kindly communicated for this work by Mr. S. P. Woodward,
who first described it in his excellent Notes on British Fossil Diademas, inserted in the
5th Decade of the ‘ Memoirs of the Geological Survey.’

FROM THE CORNBRASH. 123

PsEUDODIADEMA VAGANS, Phillips.

CIDARIS VAGANS. Phillips, Geology of Yorkshire, pl. 7, fig. 1, 1829.
DIADEMA VAGANS. Desmoulins, Etudes sur les Bchinides, p- 316, 1839.
— — Morris, Catalogue of British Fossils, 1843, p. 51.
— Morris, Catalogue of British Fossils, 2d edit., 1855, p. 72.
Woodward, Memoirs of the Geological Survey, Decade V, Notes
on Fossil Diademas.
PSEUDODIADEMA VaGaNs. Desor, Synopsis des Echinides Fossiles, p- 65.

The type specimen of this species, with many other valuable fossils, was lost in 1835 ;
there is, therefore, now some difficulty in making out the true form figured as Cidaris
vagans in the ‘ Geology of Yorkshire.’ Professor Phillips has, however, most kindly com-
municated, ea memorid, all the facts he recollects relating to this species, and has sent to me
for comparison a Diadem which he collected at Whitwell, Yorkshire, from the Bath Oolite.
In speaking of this urchin my friend observes—“ It seems, except that it is larger, to revive
my recollection of Cidaris vagans.”

Having carefully compared this specimen with Pseudodiadema depressum, which it
most nearly resembles, | find it agrees so well with that urchin in all its details which
admit of comparison, that I believe it is referable to the same species; the under part
of the test being imperfect, the base and mouth opening cannot be made out. The
examination of the upper surface, and the poriferous zones, which are well preserved,
has convinced me, that if it is regarded as a genuine example of Philips’s species, Cidaris
vagans must be considered a synonym of Pseudodiadema depressum, Agassiz. My
friend, Mr. John Leckenby of Scarborough, has kindly communicated two Diadems from
the Great Oolite of the Nab rock; these urchins are nearly indentical with Prof. Phillip’s
Whitwell specimen ; the pores in the upper part of the zones, in the Nab rock specimens,
however, manifest a disposition to become slightly bigeminal, an irregularity which I have
often seen in true unigeminal forms, and regard only as an occasional variety of the
species. In all probability these urchins may represent C. vagans, as most of the Great
Oolite Echiniderms are likewise found in the Cornbrash.

124 PSEUDODIADEMA

F. Species from the Coralline Oolite.
[a. Pores bigeminal in the upper part of the zones. |

PsEUDODIADEMA VERSIPORA, Phillips. Pl. VU, fig. 4 a, 6, ¢, de, f, g-

DIADEMA VERSIPORA. Woodward MS., Morris, Catalogue of British Fossils, 1st ed.,
1843, p. 50.
— SsUBANGULARE. Agassiz, Description des Echinodermes Fossiles de la Suisse,

pl. 17, figs. 21—25, p. 19.
— — Wright, Annals and Magazine of Natural History, 2d series,

vol. viii, p. 270.

DIPLOPODIA SUBANGULARIS. M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. u, p. 412.

— — Desor, Synopsis des Echinides Fossiles, p. 75.

DIADEMA VERSIPORA. Woodward, Memoirs of the Geological Survey, Decade V.

Notes on Fossil Diademas.

Test circular, depressed ; ambulacral areas with two rows of primary tubercles, four-
teen in each row; poriferous zones undulated below; above the equator the pairs of
pores form a double series ; inter-ambulacral areas with primary and secondary tubercles ;
spines short, stout, pomted, covered with longitudinal lines.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, one inch and a
quarter.

Description.—This beautiful Diadem, which is so characteristic a fossil of the Coral
Rag of England, was formerly mistaken for the Cidarites subangularis, Goldfuss. On
comparing, however, a fine series of our urchins with a type specimen from the Coral
Rag of Nattheim, sent by Professor Roemer, and a fine large specimen from the White
Jura of Sigmaringen, kindly sent by Dr. Fraas, of Stuttgart, the difference is very evident.
The Swiss Diadema figured by M. Agassiz, and considered to be identical with Goldfuss’s
species, agrees with our urchins in so many points of structure that I believe them to be
identical. P. versipora has from twelve to fourteen primary tubercles in the inter-
ambulacral areas, whereas P. swbangulare has only from six to eight; the test, more-
over, 1s higher and more circular, and there are more tubercles in each row in the ambu-
Jacral areas. I have, therefore, restored the manuscript name first given to this species
by Professor Phillips, and afterwards adopted by Mr. Woodward.

Pseudodiadema versipora has the test depressed ; in general it is circular; sometimes,

FROM THE CORALLINE OOLITE. 125

however, it inclines to a pentagonal form (fig. 4 a), in consequence of the prominence of
the ambulacral areas, which are finely and regularly formed (fig. 4 a, f); they have two
rows of primary tubercles on the margin of the areas, and in each row there are from
twelve to fourteen tubercles, which are nearly as large as those in the inter-ambulacra;
their summits are not deeply perforated, and they are raised on bosses with finely crenulated
summits ; in the middle third of the area there is a narrow miliary zone (fig. 4 /).

The poriferous zones, from the peristome to the equator, are slightly undulated (fig. 4 4, e) ;
near the mouth they are arranged in triple oblique pairs (fig. 4 e), but above that point they
are in single pairs (fig. 4 7); just above the equator, however, they form double pairs in
the rest of the upper part of the zone (fig. 4 a, 7); this diplopodous character is very
constant in this species, and may be detected even in very young specimens.

The inter-ambulacral areas are nearly twice as wide as the ambulacral (fig. 4 a, ¢) ;
they have two rows of primary tubercles, from twelve to thirteen in each row, and two
rows of secondary tubercles on the ambulacral side of them (fig. 4 ¢, e). The primary
tubercles are very uniform in size, and arranged with great regularity, those on the upper
part being only a little less than those in the middle of the area (fig. 4 d); the tubercle
is large (fig. 4 g), and only slightly perforated, so much so, that a little friction effaces the
aperture ; the bosses are small, and their summits are finely crenulated (fig. 4 7); the
areolas are circular, or slightly inclined to an oval form; they are all confluent above and
below (fig. 4.7), and the miliary zones form crescents of minute granules on their sides,
so that the scrobicular circles are incomplete throughout. The miliary zone down the
middle of the inter-ambulacra is broad in the middle, contracted below, and preserves its
width above : it is composed of numerous minute granules, closely set together, among
which an irregular row of larger granules extends up the middle thereof (fig. 4 d, /) ;
about the upper third of the area the granules are absent from the middle of the zone,
which is consequently naked (fig. 4 d); between the primary tubercles and the poriferous
zones there is another miliary zone, about half as wide as that which occupies the centro-
sutural region ; it is composed of like minute granules, among which a row of secondary
tubercles are disposed in the basal region ; five or six of these tubercles are about half the
size of the primary tubercles in the same region, but from the equator upwards they are
very small, and dwindle into granules (fig. 4 e, f).

The apical dise is absent in all the specimens I have examined ; the opening is large
and pentagonal, and the terminations of the areas where the disc was inserted are in many
shells curved outwards (fig. 4 a). This peculiarity in the structure of the terminal plates
may have rendered the union of the discal elements with them less firm than in other
Pseudodiademas. ‘There appear to be two varieties of the species; one with the upper
surface evenly inclined all round ; the other tumid at the angles, and depressed in the
centre above.” — Woodward ; a remark in which I entirely concur.

The mouth opening is nearly one half the diameter of the base (fig. 4 4) ; the peristome
is decagonal and unequally lobed, the ambulacral lobes being one third larger than those

126 PSEUDODIADEMA

of the inter-ambulacral; the notches are deep, and their margms are much reflexed
(fig. 4 c); the base is slightly concave in many specimens, in others it is almost flat.

The spines are well preserved 2m sz¢u in a specimen in the British Museum, from which
our figure (Pl. XII, fig. 7) is drawn ; the primary spies in that urchin (fig. 7 a, 6) are
eleven twentieths of an inch in length; the stem is marked with longitudinal lines, the
milled ring is not very prominent, and the spine may be said to be stout in proportion to
its length ; the secondary spines are one fifth of an inch in length, and are miniature
forms of the primary spines. In some specimens, as one from Steeple-Ashton, kindly
presented to me by Mr. Mackneil, of Wootton-under-Edge, the primary spines are swollen
out, and slightly bent in the middle of the stem; the head and acetabulum are large,
corresponding with the magnitude of the tubercles.

Affinities and differences.—This urchin was formerly identified with Cidarctes subangu-
laris, Goldfuss, but on comparing the German type of that species with ours, there can be
no doubt of their distinctness. Goldfuss describes his species as having six or eight large
tubercles mm each row, with crenulated bosses in all the areas; the ambulacra are prominent,
and the test is therefore pentagonal; each tubercle is surrounded with a circle of small
granules. Now Pseudodiadema versipora has twelve primary tubercles in each row in the
inter-ambulacral areas : the tubercles are consequently set close together, and all the areolas
are confluent, so that each tubercle is not surrounded by a circle of small granules. It
resembles Cidarites subangularis in possessing a double row of pores in the upper part of
the poriferous zones, and in having a row of secondary tubercles between the primary
tubercles and the pores. Pseudodiadema versipora very much resembles Pseuwdodiadema
subangulare, Agassiz, which appears to be quite distinct from the Cidarites subangularis,
Goldf. ; in fact, the beautiful figures which Agassiz has given of the Swiss urchin leads
me to think that it may be identical with our Psewdodiadema versipora. It has a greater
number of tubercles im each row than the German species, in this respect resembling the
English form; but, without the specimens were placed side by side, it would be impossible
to speak positively on the point of their entire identity.

Pseudodiadema versipora is distinguished from Pseudodiadema mamillanum, which
occurs with it in the same bed, by the double row of pores in the upper part of the zones,
and by having secondary tubercles in the imter-ambulacral areas; the bosses are likewise
smaller, and the tubercles are larger; the miliary zones are much wider, and the component
granules are smaller.

Pseudodiadema versipora resembles Pseudodiadema pentagona, M‘Coy, in having the pores
in double pairs m the upper part of the zones ; but it differs form that Great Oolite Diadem,
which is a smaller, more depressed, and pentagonal form, in having larger primary and secon-
dary tubercles, with a wider, and more granular miliary zone, in the centro-sutural region.

Pseudodiadema versipora resembles Pseudodiadema depressum in size and form, but is
distinguished from it by having the pores in double pairs in the upper parts of the zones,

FROM THE CORALLINE OOLITE. 127

and by having secondary tubercles in the inter-ambulacra. From Pseudodiadema hemt-
sphericum it is distinguished by the primary tubercles in both areas being nearly of the
same size, and by there being fewer in each row; by the secondary tubercles being limited
to the poriferous side of the primary tubercles, and by the pores being arranged in double

pairs in the upper part of the zones.

Locality and Stratigraphical position.—This species is found in the Coralline Oolite
of Wiltshire, Oxfordshire, Dorsetshire, and Yorkshire. The finest specimens, however,
are those of Wilts, where they are sometimes admirably preserved. In Switzerland the
urchins which resemble our specimens have been collected from the “ Terrain 4 Chailles,”
of the valley of the Birse, of Blochmont, and of Weissénstein.

[b. Pores unigeminal in the upper part of the zones. |

PsEUDODIADEMA HEMISPH@ERIcUM,* Agassiz. Pl. VIII, fig. 1 a, 6, ¢, d, e, f.

9,

Or

CIDARITES PSEUDODIADEMA. Lamarck, Animaux sans Vertébres, tom. iii, p.
No. 17, Ist edit., 1816.
— = Deslongchamps, Encyclopédie Methodique, tom. ii,
p- 197, No. 17, 1824.

DIADEMA HEMISPHZRICUM. Agassiz, Prodromus Mem. Soc. des Sciences Nat.
Neuchatel, p. 22, 1836.
— TRANSVERSUM. Agassiz, Prodromus Mem. Soc. des Sciences Nat.
Neuchatel, p. 22, 1836.
— PSEUDODIADEMA. Agassiz, Echinodermes Fossiles de la Suisse, 2° partie,
t. 17, figs. 49—53, p. 11, 1840.
— LAMARCEII. Desmoulins, Etudes sur les Echinides, p- 316, No. 18,
1837.
DIADEMA PSEUDODIADEMA. Agassiz and Desor, Catalogue raisonné des Echinides

Annales des Sciences Naturalles, 3™° serie, tom. vi,
p- 349, 1846.

—_ Bronn, Index Palzeontologicus, p. 193, 1849.

— Alcide d’Orbigny, Prodrome de Paléontologie Strati-
graphique universelle, tome ix, p. 27 14° étage,
No. 423, 1850.

* M. Desor having selected the specific name ‘‘pseudodiadema,” originally given by Lamarck to this
urchin, I have most reluctantly been obliged to adopt the name hemisphericum, afterwards given by
M. Agassiz to the same species, in order to avoid the double use of a specific name thus, Psewdodiadema
pseudodiadema, Lamarck. This is one of the inconveniences arising from the modern practice of converting
specific into generic names, an innovation in nomenclature which cannot be sufficiently discountenanced, for
it leads, as in this case, to an injustice to the original describer of the species, whose name should always be
associated with the form he first described, and introduces, moreover, a further confusion into the
synonyms of species, a growing evil which every true naturalist should strive to the utmost to avoid.

128 PSEUDODIADEMA

CIDARIS DIADEMA. Young and Bird, Geological Survey of the Yorkshire
Coast, pl. 6, fig. 3, p. 212, 1828.
— MONILIPORA. Phillips, Geology of Yorkshire, p. 127, 1829.
DIADEMA PSEUDODIADEMA. Wright, Annals and Magazine of Natural History,

2d series, vol. viui, pl. 12, fig. 1 a, 6, c, p. 271, 1851.
— — Cotteau, Etudes sur les chinides Fossiles du départe-
ment de l’Yonne, pl. 17, fig. 1, p. 142, 1852.
— — Salter, Memoirs of the Geological Survey, Decade V,

pl. 2.

PsEUDODIADEMA HEMISPH@RICUM. Desor, Synopsis des Hchinides Fossiles, t. 13, fig. 4,
p- 68, 1854.

DIADEMA PSEUDODIADEMA. Morris, British Fossils, 2d ed., p. 77, 1854.

‘Test hemispherical, depressed on the upper surface, flat below; ambulacral areas with
two marginal rows of primary tubercles, eighteen to twenty in each row ; poriferous zones
narrow, straight, with a moniliform line between the pores; inter-ambulacral areas with
two rows of primary tubercles, fifteen in each row, and four rows of secondary tubercles,
one row flanking each side of the primary rows; apical disc small, anal opening obliquely
oblong. Mouth opening large, peristome decagonal, unequally lobed, and deeply notched ;
spines long and needle-shaped, finely sculptured with longitudinal lines.

Dimensions.—Height, one inch and one quarter of an inch; transverse diameter, two
inches and four tenths of an inch.

Description —Lamarck’s description of his original Crdarites pseudodiadema was so
meagre and ill defined, that great doubts were entertained by Desmoulins as to the urchin
meant by the illustrious author of the ‘ Histoire Naturelle des Animaux sans Vertebres ;’
and, unfortunately, M. Dujardin has added nothing in the new edition of that great work
to the original text of this species. It would have been impossible for me to have
identified it, had not my excellent friend M. Michelin sent me a small type specimen
of Lamarck’s species from the Coralline Oolite of Commercy Meuse, which is identical
with our English forms of the same size.

Pseudodiadema hemisphericum may justly be regarded as the type of the genus, exhibit-
ing, as it does, the characters of the group im a most satisfactory manner. It appears,
moreover, to have had a wide geographical range, as it is found in the same stage of the
Coralline Oolites in Switzerland, in different departments of France, and in England.

When M. Agassiz published his ‘Prodromus,’ he was unacquainted with the original
of Lamarck’s species, a subsequent comparison of specimens, however, convinced
him that the urchin he had collected in the Swiss Jura, and named Diadema hemispheri-
cum, was identical with Diadema pseudodiadema, Lamarck, and that his Diadema trans-
versum was merely a distorted form of the same urchin.* It is probable that Diadema

* «Description des Echinodermes Fossiles de la Suisse,’ partie 2°, p. 12.

FROM THE CORALLINE OOLITE. 129

ambiguum, Desmoulins, from the Terrain Jurassique Ardennes, is another name for the
same form, but nothing can be stated positively on this point, as Desmoulins’s note on
this species is evidently written with much hesitation. M. Desor, in taking the name
Pseudodiadema to designate his genus, has retained the specific name hemisphericum for
Lamarck’s species; whilst M. Cotteau has figured and described a Corallian Pseudodiadema
under that name, which he considers to be distinct from it.

This fine large urchin has a hemispherical form; it is depressed above and flat
below, almost entirely circular at the circumference, and rarely having a pentagonal form
(Pl. VIII, fig. 1 a, 4). The ambulacral areas have two rows of marginal tubercles, which
are smaller, and placed more closely together, than those of the imter-ambulacral areas ;
they are largest at the equator, and diminish rapidly in size in the upper parts of the
areas, so that, when viewed at the equator, the primary tubercles of both areas are nearly
of equal size (fig. 1 ¢), whilst above, those of the ambulacra are disproportionately small
when compared with those of the inter-ambulacra (fig. 1 a); there are twenty tubercles
in each row, with a zigzag line of small tubercles, extending two thirds up the areas
(fig. 1d); the poriferous zones are straight (fig. 1 a, c, d); the pores are small and
unigeminal throughout, except at the base, where a few are bigeminal (fig. 1 4), and near
the peristome, where some are trigeminal (fig. 17); the septa between the two holes
forming a pair are elevated, and these elevations form a moniliform line, which extends
down the centre of the zone, separating the pores from each, and defining the boundaries
of the areas (fig. 1 ¢); there are five pairs of holes opposite each of the large inter-ambu-
lacral plates (fig. 1 @).

The inter-ambulacral areas are more thantwice the width of the ambulacral (fig.1 a, 4,c,d) ;
they are furnished with two rows of primary tubercles, having fifteen or sixteen in each
row, which have their greatest development at the equator, and gradually diminish as they
approach the apical disc (fig. 1 a), and the peristome (fig. 1 4); the primary are flanked on
each side by one or more rows of secondary tubercles down the centre of the area
(fig. 1 c, d); the miliary zone consists of two rows of secondary tubercles, which separate
the primary rows from each other (fig. 1 d), and two rows of secondary tubercles separate
the primaries from the poriferous zones (fig. 1d); the secondary tubercles are very
irregular in their size and arrangement; they are best developed at the base and equator
of the test (fig. 1 4, c); besides the primary and secondary tubercles just described, the
surface of the plates is covered with numerous granulations, which form circles, more or
less complete, about the base of the tubercles (fig. 1 @).

The tubercles of both areas, at and near the equator, are raised on prominent bosses,
the summits of which are all finely crenulated ; the base is surrounded by a narrow areola,
around which small granules and minute tubercles form more or less complete scrobicular
circles (fig. 1 ¢); the areolas at the equator are all confluent above and below, whilst those
in the upper part of the areas are nearly, if not quite, complete (fig. 1 a).

It is remarkable how often the apical disc of this species is preserved 2” situ (fig. 1 a) ;
17

130 PSEUDODIADEMA.

the genital plates are of a pentagonal form (fig. 1 e) ; the anterior pair are the largest, and
the right antero-lateral, supporting the madreporiform body, is much larger than the left
antero-lateral ; the postero-lateral and single plates are about the same size; the genital
holes are small, and pierced near the external prominent angle of the plates; the ocular
plates are small, heart-shaped bodies, placed at the summits of the ambulacra, which they
terminate ; the eye hole is marginal, and proportionally large; the anal opening is oblong,
its longest diameter extending obliquely across the test ; the surface of all the elements of
the apical disc is covered with small, nearly equal-sized granules.

The base is flat (fig. 1 ¢), the mouth opening is large, being more than one half the
diameter of the base; the peristome is decagonal, and divided into ten lobes by deep
notches, the ambulacral bemg much larger than the inter-ambulacral lobes (fig. 1 6).

The spines are not preserved in any English specimens I have seen. Those figured
mm situ, by Agassiz, are long and needle-shaped, and thei surface is covered with fine
longitudinal lines.

Affinities and differences.—Pseudodiadema hemisphericum differs so much from all our
other English species of this genus, that it is impossible to mistake it for either of them,
Some juvenile specimens, however, have an air of resemblance to Hemicidaris pustulosa;
arising from the disproportionate size between the tubercles at the base and equator of
the ambulacra, and those occupying the upper portion of these regions; but the presence
of secondary tubercles in the inter-ambulacra, flanking both sides of the primary tubercles,
serves as a diagnostic character, no Hemicidaris having any secondary tubercles in the
inter-ambulacral regions; moreover, the number of the primary tubercles in each row is
considerably more in Pseudodiadema hemisphericum than in Hemicidaris pustulosa.

Lamarck’s species is distinguished, according to M. Cotteau, from the urchin
figured by him under the name Diadema hemisphericum, “dune maniere positive
et constante, par ses tubercles secondaire plus developpés, plus nombreaux, et plus regu-
herement disposés au milieu des aires inter-ambulacraires ; il s’en distingue également par
les entailles plus profondes de son ouverture buccale.”*

Pseudodiadema hemisphericum, Agass., resembles Pseudodiadema Orbignyanum, Cotteau,
but the latter is readily distinguished from it by the greater number, regularity, and
uniformity of its secondary tubercles, and the smaller size of the primary tubercles. These
three species, which are all characteristic of the Coral Rag, resemble each other very
much, and are only distinguished by the number and disposition of their secondary
tubercles, which are rare in Pseudodiadema hemisphericum, Cotteau, more numerous
in Pseudodiadema hemisphericum, Agass., and very abundant in Pseudodiadema
Orbignyanum, Cottean.

Locality and Stratigraphical position—This species is very rare in the Coralline

* «#tudes sur les Hchinides Fossiles,’ p. 144.

FROM THE CORALLINE OOLITE. 131

Oolite of Wilts. The specimen figured in Pl. VIII, fig. 1, was collected in the neighbour-
hood of Calne, It is more abundant in the Coralline Oolite of Yorkshire. Many fine
specimens having been obtained from Malton and its vicinity. Its foreign distribution
occupies a wide area in France. It is found in the “ Corallien étage of Besancon, Saint-
Mihiel, La Rochelle, Druyes (Yonne), and Commercy (Meuse) ;” and in Switzerland in the
neighbourhood of Soleure. It is everywhere a very characteristic fossil of the Coral Rag.

PSEUDODIADEMA RADIATA, Wright, nov. sp. PI. VII, fig. 3 a, 6, Gv dNCs fi

Test circular, depressed, inflated at the sides; ambulacral areas narrow, with two
rows of primary tubercles, twelve in each row, rather smaller than those of the inter-
ambulacra; poriferous zones straight, pores unigeminal throughout ; inter-ambulacral areas
with two rows of primary tubercles, twelve in each row, separated by a wide miliary zone
filled with several rows of granules; base concave, mouth opening small, peristome
unequally decagonal.

Dimensions.—Height, rather more than seven twentieths of an inch; transverse
diameter, nine tenths of an inch.

Description—The test of this species is circular, and nearly equally depressed on
the upper and under surface (fig. 3 c); the sides are rather tumid, and the ambulacral
tubercles are only a little smaller than those of the inter-ambulacral. The ambulacral
areas form no prominence on the sides as in so many other Pseudodiademas (fig. 3 a) ;
they are more than half the width of the inter-ambulacral; and are occupied by two rows
of primary tubercles (fig. 3 d, e), of which there are twelve in each row; their bosses are
small, and set closely together, and their summits have well-marked crenulations (fig. 3,/) ;
down the centre of the area there is a single zigzag line of granules, which becomes double
about the middle of the area; transverse branches of granules separate the areolas ; the
tubercles are of a very uniform width throughout, and diminish gradually in size towards
both ends of the area.

The poriferous zones are narrow, and nearly straight, and the pores are unigeminal
throughout ; the pores forming a pair are contiguous, with thin septa; there are three
pairs of pores opposite the ambulacral plates, and four pairs of pores opposite one of the
inter-ambulacral plates (fig. 3 /).

The inter-ambulacral areas are not quite twice the width of the ambulacral; they have
two rows of primary tubercles, of which there are twelve in each row (fig. 3d) ; each plate
(fig. 3,7) is occupied by a wide areola, the boss is not prominent, its summit is marked
with twelve crenulations, and the spinigerous tubercle is small, flat, and finely perforated

132 PSEUDODIADEMA.

(fig. 37); between the areola and the pedal pores there is a narrow lateral miliary zone,
formed of two rows of small granules, among which two or three small secondary
tubercles are interspersed (fig. 3,f); the central miliary zone is wide; on each plate there
are two rows of small, close-set granules (fig. 3 7), making four rows of granules at the
equator; a little way above that point they bifurcate, and on the upper part of the area
a few scattered granules only are observed, the surface of the plates being almost naked
(fig. 3d). Like the ambulacral tubercles, those of the inter-ambulacra diminish very
gradually in size towards both ends of the area.

The base is slightly concave, from the tumidity of the sides of the test; the mouth
opening is small (fig. 3 4, e), four tenths of an inch in diameter; the peristome is slightly
notched, the ambulacral lobes being larger than the inter-ambulacral (fig. 3 e).

The disc opening is nearly round, but the plates are unfortunately absent.

Afimties and differences.—This species resembles Pseudodiadema mamillanum, Roemer,
im having a few small secondary tubercles near the base, between the poriferous zones and
the primary tubercles, and in having the pores unigeminal ; but it is readily distinguished
from that fine species by having smaller tubercles, much less prominent bosses, and a
wider miliary zone; the sides of the test are likewise much more tumid, the mouth
opening is smaller, and the peristome is more equally lobed.

From Pseudodiadema versipora, which occurs with it i the same rock, it is readily
distinguished by the unigeminal character of its poriferous zones, and the absence of
large secondary tubercles from the inter-ambulacral plates (Pl. VII, fig. 47).

Locality and Stratigraphical position —This is a very rare species ; it was collected
from the Coral Rag, near Steeple Ashton, Wilts, associated with Pseudodiadema versipora.

PsEUDODIADEMA MAMILLANUM, Roemer. PI. VIII, fig. 2 a, 6,¢,d; Pl. XII, fig. 9.

CIDARITES MAMILLANUM. Roemer, die Versteinerungen des Norddeutschen Oolithen-
Gebirges, t. 2, fig. 1 a, 6, e, p. 26.
DIADEMA MAMILLANUM. Agassiz and Desor, Catalogue raisonné Annales des Sciences
Naturelles, 3™° série, Zool., tom. vi, p. 347.
— _ SPINOSOSUM. Agassiz, Catalogus Systematicus, p. 8.
— Davipsonit. Wright, Annals and Magazine of Natural History, 2d series,

vol. xiii, p. 170, pl. 13, fig. 2 a—e.
— MAMMILLATUM. D’Orbigny, Prodrome de Paléontologie, tome ii, p. 27,
14° étage Corallien.
PsEUDODIADEMA MAMILLANUM. Desor, Synopsis des Echinides Fossiles, p. 64.
DIADEMA MAMILLANUM. Woodward, Memoirs of the Geological Survey, Decade V.
Notes on British Fossil Diademas.

FROM THE CORALLINE OOLITE. 133

Test circular, depressed; ambulacral areas wide, with two rows of primary tubercles
nearly as large as the inter-ambulacral; poriferous zones narrow ; pores unigeminal on the
sides and upper part of the zones, trigeminal near the mouth; inter-ambulacral areas
with two rows of primary tubercles, and two short rows of secondary tubercles on the zonal
sides of the primaries ; the bosses of both areas nearly of the same size, large, prominent,
and conical ; spinigerous tubercles of both areas of the same size, large, and widely perfo-
rated. Mouth opening large, peristome decagonal, ambulacral lobes twice the width of
the inter-ambulacral ; spines long, round, stout, and covered with longitudinal lines.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, one inch and
three tenths.

Description.—This Diadem was first discovered in the Coral Rag of Hildesheim, and
figured and described by M. Roemer in his work on the ‘Oolitic Fossils of Northern
Germany ;’ it has subsequently been found in the Coralline Oolites of France. When
I found this species, some years ago, in the Coral Rag of Wiltshire, I was then unable to
identify it with any published species, and figured and described it the ‘ Annals of Natural
History’ under the name Diadema Davidsoniz, M. Roemer’s figure being very indistinct,
and without details, did not furnish sufficient data for identification. Since the publication
of that paper, M. Desor has compared my figures and descriptions with the moulds in the
Museum of Neuchatel, attributed to Diadema mamillanum, and he says, “n'ai pas trouvé
de raison suffisante pour les distinguer.* Mr. Woodward} states that ‘the British forms
of this species agree perfectly with specimens received from Dr. Roemer, labelled U. Coral
Rag, Hildesheim, Hanover.” ‘There is, therefore, no doubt that Diadema Davidsonii is
identical with Roemer’s species.

This beautiful urchin has a regular cylindrical test, not at all inclined to the pentagonal
form of many of its congeners (fig. 2 a, 6); the ambulacral areas are about three fourths
the width of the inter-ambulacral, and nearly of a uniform breadth throughout, tapering
gracefully inwards towards their superior third (fig. 2 a); the contraction assumes the
form of a gentle curve, slightly inclined towards the centre. The double row of tubercles,
which are nearly as large as those of the inter-ambulacra, gradually increase in size from
the peristome to the equator, where three pairs are about the same size; from this point
upwards they gradually decrease, and terminate in two pairs of minute rudimentary
tubercles near the apical disc. A single row of granules, arranged in a zigzag form,
separates the two rows of primary tubercles from each other, a larger granule marking
each re-entrant angle (fig. 2 d); the areolas abut against the poriferous zones (fig. 2 d),
without the intervention of any granules between these eminences and the pores.

* Desor, ‘Synopsis des Bchinides Fossiles,’ p. 64.
+ «Memoirs of the Geological Survey,’ Decade V. Notes on British Fossil Diademas.

134 PSEUDODIADEMA.

The poriferous zones are very narrow; the pores are contiguous, and unigeminal
throughout (fig. 2 @), except at the wide inter-tubercular spaces around the mouth, where
they fall into triple oblique pairs (fig. 2 4); in the upper third of their course, the zones
curve slightly inwards, and the pores are set very closely together in this region. There
are five pairs of pores opposite each inter-ambulacral plate, and nearly a like number
opposite the ambulacral plates (fig. 2 d).

The inter-ambulacral areas are four tenths of an inch in width, and only one fourth
wider than the ambulacral areas. They retain their breadth very uniformly throughout, and
are occupied by two rows of primary tubercles, of which there are ten in each row; the
bosses are large and prominent; those at the equator occupying nearly the entire surface
of the plates (fig. 2 d); their summits are sharply crenulated, and the spinigerous tubercle
is widely perforated; from the peristome to the equator (fig. 2 6, d), or for about two
thirds the length of the area, there is a row of small secondary tubercles between the
zones and the primaries, which are raised on mammillated bosses, with crenulated summits
(fig. 2 d); the miliary zone is narrow, and composed only of two rows of granules, which
descend down the tract of the zigzag central suture (fig. 2 d), there being five granules on
each plate (fig. 2 d).

The tubercles of both areas stand prominently out from the surface of the test, in
consequence of the size of the mammillary bosses, which are unusually conical in this
species; from the mouth to the equator the tubercles of both areas are nearly alike in size
and number (fig. 2 4, c), but on the upper part of the test those of the ambulacral areas
become much smaller and more numerous (fig. 2 @) than those of the inter-ambulacral
areas.

The mouth opening is wide, about eleven twentieths of an inch (fig. 2 4); the peris-
tome is decagonal, and unequally lobed, the ambulacral being twice as large as the inter-
ambulacral lobes. Since Pl. VIII was printed, I have obtained a slab with the test and
spines 7” sifu thereon, and which is figured in Pl. XII, fig. 8. The primary spines
(fig. 8 a, 6) are nine tenths of an inch in length; the head is well defined by a prominent
milled ring; the stem, which is cylindrical, tapers uniformly from the ring to the point,
which is rather blunt, and the surface is covered with fine longitudinal lines; the secondary
spines (fig. 8 ¢) are nearly three twentieths of an inch in length, and are miniature repre-
sentatives of the primaries.

The disc opening is wide (Pl. VIII, fig. 2 d); its form cannot be described, as the
plates around its margin are more or less fractured. The discal elements are lost in all
the specimens I have yet seen.

Affinities and differences.—The great width of the ambulacral areas, and the uniformity
in the size and number of the primary tubercles at the base and equator of the test

(fig. 2 4, ec, d), render the diagnosis between this species and its congeners easy and
decisive.

FROM THE CORALLINE OOLITE. 135

From Pseudodiadema versipora it is distinguished by the unigeminal character of its
poriferous zones, the greater prominence of its bosses, the smaller size of its tubercles, the
greater width of the ambulacral areas, and the narrowness of its miliary zones. From
Pseudodiadema radiata, which has likewise unigeminal pores, by the size of the bosses
and the narrowness of the miliary zones, and the absence of the lateral tumidity which
characterises that species. From Psewdodiadema hemisphericum it is distinguished by the
uniformity in size between the ambulacral and inter-ambulacral tubercles, which are very
unequal in that large species; and by the smallness of the secondary tubercles, and their
limitation to the zonal sides of the area; whereas the secondary tubercles are developed on
both sides of the primaries in Pseudodiadema hemisphericum, a character which forms a
good diagnosis between these two Coralline Oolite forms.

Locality and Stratigraphical position —I\ have collected this species in the Clays and
Limestones of the Coralline Oolite, at Calne, Wilts, associated with Hemicidaris intermedia,
Acrosalenia decorata, Echinus gyratus, and Echinobrissus scutatus. On many slabs all
these species are sometimes found clustered together in a more or less fragmentary con-
dition. It has been collected from the Coral Rag, at Redcliff, near Weymouth ; specimens
from this locality are in the British Museum, and Geological Museum, Jermyn Street.

On the Continent, it has been collected by M. Roemer from the Upper Coral Rag of
Hildesheim, Hanover, and in the “‘Corallien étage de la Rochelle, de Verdun, France.””—
Desor, It is everywhere a rare species.

History —First described and figured by M. Roemer under the name Cidarites
mamillanum ; afterwards figured and described as Diadema Davidsoni, in the ‘ Annals of

Natural History.’ But a comparison of the English with the Foreign types has proved
them to be identical.

136

NOTES

On Forricn JURASSIC SPECIES OF THE GENUS PSEUDODIADEMA weary ALLIED TO

BRITISH FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EneiisH OoLitEs.

A. Pores ungeminal in the upper part of the zones ; no secondary tubercles.

PsEUDODIADEMA SUBCOMPLANATUM, d Orbigny. Prodrome de Paléontologie, p. 319.

Test small, depressed, pentagonal; tubercles of both areas at the base, and equator of
the test proportionately large, prominent, and equal sized; ambulacra prominent, with
eight or nine tubercles in each row, nearly as large, but more crowded together at the
base and equator; diminishing more rapidly in size in the upper part of the area than
those of the inter-ambulacra. Inter-ambulacral areas with eight rows of large prominent
primary tubercles, and four small secondary ones on their zonal sides at the base; miliary
zone narrow, with two rows of granules; nearly related to P. complanatum, Agass., and
to P. depressum, Agass. It differs from the former in having a much larger mouth-
opening, and from the latter in having larger tubercles, a narrower miliary zone, and four
small secondary tubercles at the base.

Dimensions.—Height, three tenths of an inch; transverse diameter, four fifths of an
inch.

Formation.—Grande Oolite, 11° étage Bathonien, de Ranville, Luc (Calvados).

Collections.—Deslongchamps, Michelin, d’Orbigny, my Cabinet.

PSEUDODIADEMA COMPLANATUM, Agassiz. Syn. Diadema complanatum, Agass., Echinod.
Suisse, part u, tab. 17, fig. 31—35.

‘Test small, very much compressed; the ambulacral are smaller than the inter-
ambulacral tubercles, and they diminish more rapidly in size at the upper surface, but in

FOREIGN OOLITIC PSEUDODIADEMAS. 137

other parts those of each area very much resemble one another; there are fewer tubercles
in a row in the ambulacra than in the inter-ambulacra; the poriferous zones are narrow,
and the pores are unigeminal on the upper surface ; the mouth opening is small, and the
decagonal peristome is divided into nearly equal-sized lobes; there are no secondary
tubercles at the base of the inter-ambulacra.

Dimensions.—Height, three twentieths of an inch; transverse diameter, two fifths of
an inch.

Formation.—“ Portlandien inférieure (Astartien) de Reedersdorf (Haut Rhin), du
Jura Neuchatelois, des bords du Doubs, de Laufon.

Collections —MM. Gresly, Thurmann. Desor. Rare.”

PsnUDODIADEMA INZQUALE, Agassiz. Syn. Diadema inequale, Agassiz, Cat. syst., p. 8.

Test small, subpentagonal, and depressed; tubercles small, uniform, and numerous ;
inter-ambulacral tubercles arranged near the poriferous zones; miliary zone wide, and
naked from the equator to the apical disc; mouth opening of moderate size ; peristome
divided into equal-sized lobes ; opening for the disc large, and oblong ; the approximation
of the tubercles into groups of four rows, separated by the wide naked miliary zone in the
upper part of the areas, serves to distinguish this species from allied forms. Jt differs
from P. superbum in having the tubercles set closer together, and from P. textum in
having wider ambulacral areas.

Dimensions.—Height, two fifths of an inch; transverse diameter, four fifths of an
inch.

Formation.—Kellovien de Marolles, de Chaufour, et Montbizot (Sarthe), Lifol
(Vosges). Common.

Collections —MM. Michelin, d’Archiac, d’Orbigny. The specimens in my Cabinet
were kindly sent me by M. ‘Triger, of Le Mans.

PsEUDODIADEMA SUPERBUM, Agassiz. Syn. Diadema superbum, Agass., Echinod. Foss.
de la Suisse, tab. 17, fig. 6—10, p. 23,
part i.
Test small, subperitagonal, and sometimes inflated at the sides; ambulacral tubercles
18

138 FOREIGN OOLITIC PSEUDODIADEMAS.

smaller than the inter-ambulacral, diminishing rapidly in size on the upper part of the
areas; inter-ambulacra with two rows of primary tubercles, but no secondary ones;
areolas surrounded by complete circles of small granules; miliary zone wide, with fine
granulations at the equator, but naked at the upper part; mouth-opening small, situated
im a concavity; discal opening large and oblong. ‘This species very much resembles
P. inequale, and it may be only a small variety of that Kellovian form.

Dimensions.—Height, one quarter of an inch; transverse diameter, half an inch.

formation —Oxfordien marnes, des Vaches-noires, Calvados; de Mont Vohayes, Jura
Bernois, de Belfort.

Collections.—Museum Paris, Coll. MM. Gresly, Michelin, my Cabinet.

PSEUDODIADEMA MAGNAGRAMMA, Wright, nov. sp. Davidson’s MSS., pl. 3 bis, figs. 4—6.

Test circular depressed, with two rows of tubercles in the inter-ambulacra; ambulacra
two thirds the width of the inter-ambulacra ; tubercles of both areas set on bosses, with
a very large base; those of the ambulacra are a little smaller than those of the inter-
ambulacra; the ranges of tubercles in both areas are separated by a single row of small
granules; the discal opening is small, and the mouth opening is concealed; there are
no secondary tubercles, and the pores are strictly unigeminal.

Dimensions.—Height, nine twentieths of an inch; transverse diameter one inch and
one twentieth of an inch.

Formation. — Collected from the Portland beds, between Portel and Equihen,
Boulonnais.

Collections.—Myr. Davidson, M. Bouchard Chantereaux, my Cabimet.

B. Pores unigeminal in the upper part of the zones, with two or four rows of secondary
tubercles in the inter-ambulacra.

PsEUDODIADEMA PLACENTA, Agassiz. Syn. Diadema placenta, Agassiz, Echmod. Foss:
Suisse, tab. 17, figs. 16—20.

FOREIGN OOLITIC PSEUDODIADEMAS. 139

Test circular, much depressed on the upper and under surfaces ; tubercles nearly the
same size in both areas; areolas surrounded by a circle of granules; four rows of small
secondary tubercles between the peristome and the equator; mouth opening of moderate
width ; peristome not deeply notched.

Dimensions.—Height, eleven twentieths of an inch; transverse diameter, one mch and
nine twentieths.

Formation.—“ Corallien inférieure (Terrain a chailles) du Fringeli (Canton de Soleure),
de Nantua, des environs de Salins, de Druyes (Yonne).” Desor.

Collections. —Museum Neuchatel, Coll. MM. Gressly, Marcou, Cotteau. Common.

PsEUDODIADEMA Orsienyanum, Cotteaw. Syn. Diadema Orbignyanum, Cotteau,
Echinides Foss., tab. 17, fig. 2—6.

‘Test circular hemispherical, flattened at the base, and depressed on the upper surface ;
ambulacra narrow, with two rows of primary tubercles ; inter-ambulacra with two rows of
primary tubercles, and six or eight rows of small equal-sized secondary tubercles; the
primary tubercles of both areas are about the same size; those of the inter-ambulacra are
closely surrounded by numerous secondary tubercles; apical disc small, genital plates
narrow ; poriferous zones narrow; pores falling into triple oblique pairs near the mouth,
but strictly unigemmal above; mouth opening large; peristome deeply notched ; lobes
very unequal.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, one inch and
seven tenths of an inch.

Formation —Corallien de Coulanges sur Yonne, Druyes, et Chatel-Censoir, (Yonne),
Profont (Aim), Hobel (Canton de Soleure).

Collections. — Museum Bale, Coll. MM. Cotteau, Renevier. Plaster mould, my
Cabinet.

PsEUDODIADEMA TETRAGRAMMA, Agassiz. Syn. Diadema tetragramma, Agass., Echinod.
Foss. Suisse, tab. 17, figs. 39—43.

Test circular, hemispherical, depressed ; inter-ambulacra with four rows of secondary

140 FOREIGN OOLITIC PSEUDODIADEMAS.

tubercles, which at the base, and up to the equator, nearly equal in size the two rows of
primary tubercles; this imparts a tetragrammous appearance to this species, which is lost,
however, in the upper part of the area, where there are only two rows of tubercles;
ambulacra moderately wide, their tubercles nearly as large as those of the inter-
ambulacra; pores unigeminal throughout; apical disc small and ring-like, all the plates
covered with a fine granulation; rows of small granules separate the areolas from each
other; mouth opening large; peristome not deeply notched.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, one inch and
one twentieth of an inch.

Formation. —Corallien de Bensancon, de Chatel-Censoir (Yonne).

Collections—Museum of Vienna (Collection Dudressier), Coll. M. Cotteau. Very
rare.

PSEUDODIADEMA QUALE, Agassiz. Syn. Diadema equale, Agass., Echinod. Foss.
Suisse, part ui, tab. 17, figs. 36—38.

Test circular hemispherical, depressed above; ambulacral rather smaller than the
inter-ambulacral tubercles; areolas confluent; four rows of small secondary tubercles,
which only extend to the equator; upper part of the miliary zone naked; mouth opening
moderately large; peristome not deeply notched; pores strictly unigeminal, falling into
triple oblique pairs near the mouth. ‘This species very much resembles P. hemisphericum,
but the smallness of the secondary tubercles, the shortness of the rows, and the nakedness
of the upper part of the miliary zone, distinguish it from that allied form.

Dimensions—Height, eleven twentieths of an inch; transverse diameter, one inch
and two fifths.

Formation.—Argovien des environs d’Arau. Kellovien des environs de Quingey.

Collections —Museum Bale, Coll. Zschokke, Marcou. Very rare.

PsEUDODIADEMA AFFINE, Agassiz. Syn. Diadema affine, Agass., Hchinod. Foss. Suisse,
part 11, tab. 17, figs. 54—58.

Test small, circular, depressed; the secondary tubercles at the zonal sides of the

FOREIGN OOLITIC PSEUDODIADEMAS. 141

primaries nearly equal the latter in size; those near the centro-suture are much smaller :
miliary zone covered with small granulations above; pores strictly unigeminal; areolas
confluent at the equator, separated by small granules above; mouth opening small ;
peristome scarcely notched.

Dimensions. — Height, three tenths of an inch; transverse diameter, seventeen
twentieths of an incb.

Formation.—* Jura superieur du Dept. du Doubs. Trés rare.’’ Desor.

Collection Museum Neuchatel, Coll. Renaud-Comte (Musée Besangon).

PsEUDODIADEMA PLANISsIMUM, Agassiz. Syn. Tetragramma planissimum, Agass., Echinod.
Foss. Suisse, part ii, tab. 14, figs. 1—3.

Test small, circular, very much depressed; imter-ambulacra with four rows of
secondary tubercles, which at the base and equator equal the two rows of primary
tubercles in size; these divisions of the test therefore support six rows of equal-sized
tubercles; in the upper part of the area the secondary tubercles become much smaller ;
ambulacra with two rows of tubercles as large as those in the inter-ambulacra; miliary
zone very narrow ; mouth opening small; peristome scarcely notched.

Dimensions.— Height, one fifth of an inch; transverse diameter, four fifths of
an ich.

Formation.— Portlandien moyen (Calcaire a Tortues) de Soleure. Marnes Strombiennes
de Porrentruy.” Desor.

Collection Museum Neuchatel, Coll. Gressly, Thurmann. Very rare.

C. Pores bigeminal in the upper part of the zones ; inter-ambulacra with two rows of
secondary tubercles.

PsEUDODIADEMA SUBANGULARE, Goldfuss. Syn. Cidarites subangularis, Goldfuss,
Petrefacta, Germaniz, tab. 40, fig. 8.

Test pentagonal, depressed ; ambulacra one half the width of the inter-ambulacra, with
two rows of tubercles 10 or 12 in each row; inter-ambulacra with two rows of primary
tubercles 10 or 12 in each row, and two rows of small secondary tubercles on the zonal
sides of the primaries, extending three fourths of the length of the area; bosses small

142 FOREIGN OOLITIC PSEUDODIADEMAS.

and sharply crenulated ; primary tubercles of both areas nearly of the same size, large,
round, and prominent; areolas narrow, and encircled with small, round, spaced-out
granules ; poriferous zones narrow; pores bigeminal in the upper part of the zones;
miliary zone of moderate width, with a few granules at the equator, but naked in the
upper part of the area; mouth opening less than one half the diameter of the test;
peristome decagona!, divided by notches into nearly equal-sized lobes.

Dimensions.—Height, three fifths of an inch; transverse diameter, one inch and
a half.

Formation.—Coral Rag of Nattheim and Sigmaringen, Wiirttemberg; of Thurnau
and Muggendorf, Bavaria; of Galgenberg, near Hildesheim, and
Lindenberg, near Hanover; of Chatel-Censoir and Druyes,
(Yonne) ; Argovien? of Randen ; “ Oxfordien a Belemnites hastatus
du Jura Neuchatelois.” Desor.

Collections.—In all the Foreign Collections of Jurassic Fossils. The specimen
whence the diagnosis given above has been drawn, was sent
me by Dr. Fraas of Stuttgart, as a type of Goldfuss’s species. It
was collected from the White Jura 6 and « of Sigmaringen.

In this specimen the pores are unigeminal in the upper part of the zones, as in the
one figured by Goldfuss ; but as several plates belonging to the upper part of the areas
are absent, and the pores at the same time are much concealed by the matrix, the
bigeminal arrangement may nevertheless have existed in this specimen. In another
small Diadem from the Coral Rag of Nattheim, sent me by Professor Roemer, from the
Bonn Museum, as typical of Goldfuss’s species, the pores are distinctly bigeminal; in a
third specimen, from the Coral Rag of Druyes, sent by M. Cotteau, the pores are like-
wise bigeminal. I have not cited the specimens so beautifully figured as Deadema
subangulare, by M. Agassiz,* because they certainly are not identical with Goldfuss’s type ;
they more probably belong to Pseudodiadema versipora of the English Coral Rag.
Mr. Woodwardt says, “ We cannot agree with M. Agassiz in considering either of these
forms referable to the ‘ Cudarites subangularis of Goldfuss; German specimens agreeing
with Goldfuss’s figure and description, in the presence of only a single series of pores, are
in the British Museum.” Whether the diplopodous forms are only a variety, or a distinct

species, it is impossible to decide, without a better series of specimens for comparison than
I possess at present.

* ¢Wehinodermes Fossiles de la Suisse,’ part u, pl. 17, figs. 21—29.
+ Notes on British Fossil Diademas. ‘Mem. of the Geological Survey,’ Decade V.

HEMIPEDINA. 143

Genus—HEMIPEDINA, Wright. 1855.

This rare genus is composed of neat and highly ornamented urchins, in general much
depressed on their upper surface, and with a flat or slightly concave base. ‘The ambu-
lacral areas are narrow and straight; the pores in the poriferous zones are arranged in
single pairs; the inter-ambulacral areas are, in general, more than double the width of the
ambulacral, with two, four, six, or eight rows of tubercles, arranged in general abreast on
the same tubercular plate.

The tubercles are perforated, and set on bosses with smooth, uncrenulated summits ;
one row of tubercles extends from the peristome to the disc; the other rows, when there
are four and six rows in the area, stop short at the equator, or between the equator and the
disc; the upper part of the miliary zone is therefore in general wide, and covered with a
fine granulation.

The apical disc is large; the genital plates are expanded and foliated ; the eye holes
are perforated in the centre of the ocular plates, which are large.

‘The mouth opening is of moderate dimensions, and the peristome is divided into ten
nearly equal-sized lobes.

The spies are long, slender, and needle-shaped; those that are known equal in
length the diameter of the test, and their surface is sculptured with delicate, longitudinal
hnes.

Hemipedina is related to Pseudodiadema in having the pores unigeminal, and the
tubercles perforated; but is distinguished from Pseudodiadema by the absence of crenu-
lations from the summits of the bosses.

It is related to Pedina in possessing perforated and uncrenulated tubercles; but is
distinguished from that genus in having the pores unigeminal (Pedina having the pores
trigeminal like Achinus); the elements of the apical disc are likewise more largely
developed.

Hemipedina is related to Echinopsis in possessing uncrenulated and perforated
tubercles, with unigeminal pores; but is distinguished from Mehinopsis by the nar-
rowness of the ambulacral areas, the general depressed form of the test, the shape of the
mouth opening, and the deep decagonal lobes of the peristome (that of Achinopsis being
almost deprived of incisions), together with the greater size and development of the
elements of the apical disc.

Hemipedina, as far as we at present know, is composed of Oolitic species which com-
menced in the Lower Lias, and extended into the upper division of the Oolites, each stage
possessing its own specific forms.

144 HEMIPEDINA.

A. Species from the Lnas.

Hemipepina Brcuut, Broderip. Pl. IX, fig. 1 a, 6.

Ciparis Brcuet. Broderip, Geological Proceedings, vol. ui, p. 202.
DiapEmMa BrcHet. Morris, Catalogue of British Fossils, 1st edition, p. 51.
— — Morris, Catalogue of British Fossils, 2d edit., p. 76.
Ecutnopsis Brcurt. Woodward, Memoirs of the Geological Survey, Decade V. Notes om
Fossil Diademas.
Hemipepina Becuzr. Wright, Annals and Magazine of Natural History, 2d series, vol. xvi,
p- 96.

Test small, much crushed, and covered over with spines; ambulacra with two rows of
tubercles ; inter-ambulacra with four or six rows of tubercles; spines long, slender, and
needle-shaped, four fifths of an inch in length, with longitudinal lines on their surface.

Description.—The test of this specimen, and the one in the collection of the Geological
Society, which appears to belong to the same species, is so much covered up with spines
and adherent matrix, that it cannot be sufficiently developed to show the details of its
structure. The ambulacral areas have two rows of small tubercles placed on the margins of the
plates ; and the inter-ambulacral areas have four or six rows of tubercles abreast. The
spines are long, slender, and needle-shaped ; they measure four fifths of an inch in length,
have a small conical head, a prominent, narrow, milled ring,
which tapers gradually from the ring to the point; their surface is finely marked with
longitudinal lines.

and a long, slender stem,

Affinities and differences.—This species might be mistaken for Hemipedina Bowerbankii,
but its test is smaller, and its spines are longer and more slender; the head is more
conical, the milled ring is narrower and more prominent; I believe it is identical with
Mr. Broderip’s species.

Locality and Stratigraphical position.—This specimen has been kindly communicated,
together with the following species, by my friend Mr. Bowerbank, who collected it from
the Lower Lias at Lyme Regis, from one of the layers of marl which inter-stratifies the
beds of limestone.

FROM THE LIAS. 145

Hemrpeprna Bowrrsanktt, Wright. Pl. IX, fig. 2 a, 4, ¢.

HemrIrepINA BownrBankit. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 96.

Ambulacral areas narrow, with two rows of marginal tubercles, rather smaller than
those of the inter-ambulacra, one tubercle on every third or alternate plate ; inter-ambu-
lacral areas wide, with six rows of tubercles abreast, each surrounded by a delicate areolar
circle; spines long and. needle-shaped, deeply sculptured with longitudinal lines. Form
unknown, as the test is crushed. j

Dimensions —One inch and one twentieth of an inch in diameter ; height unknown.

Description.—The only specimen of this species I have seen is the one collected by my
friend Mr. Bowerbank, and figured in Pl. IX, fig. 2. The test is unfortunately much
crushed, but a sufficient number of plates are preserved to enable me to make a short
description of this beautiful Liassic form.

The ambulacral areas are more than one third the width of the inter-ambulacral ; they
are composed of narrow, hexagonal plates (Pl. IX, fig. 2 4); on every third plate a small
tubercle is developed, about midway between the zones and the central suture, but nearer
to the latter; on the intervening plates there are only two or three small granules on each ;
the poriferous zones are narrow and straight, the pairs of pores having an oblique direc-
tion upwards and inwards ; there are four ambulacral plates opposite each inter-ambulacral
one ; the number of plates in a column cannot be ascertained, as all of them are more or
less incomplete.

The mter-ambulacral areas are more than double the width of the ambulacral; they
are composed of narrow, pentagonal plates (fig. 2 4); on the centre of each is a primary
tubercle, and on each side a smaller secondary tubercle ; these three tubercles are disposed
nearly on the same line, and two smaller tubercles are developed near the lower angles
of the plate; the central tubercle is surrounded by an areola, and an incomplete circle of
small, spaced-out granules encircles it; granules of the same size form circles around
the secondary tubercles, but in them the areola is small or altogether absent.

At the equator each inter-ambulacra is provided therefore with six rows of tubercles,
which are arranged nearly all abreast, and four rows of smaller tubercles placed near the
lower angles of the plates; but in the upper part of the area, the rows of secondary
tubercles dwindle into granules, and finally disappear (fig. 2 a); there are four pairs of
pores opposite each large inter-ambulacral plate (fig. 2 4).

The apical disc is not preserved ; and as the base is imbedded in the clay, the structure

of the under surface is unknown.
19

146 HEMIPEDINA.

The spines, many of which are preserved 2m si¢w, are long and needle-shaped ; they are
shorter and stouter than those of Hemipedina Bechei (fig. 1 6), although the diameter of
the test of H. Bowerbankii greatly exceeds that of H. Becher ; the spines of H. Bower-
bankii ave three quarters of an inch in length; the head does not taper much towards
the acetabulum (fig. 2c); the milled ring is thick, but not so prominent as in H. Becher ;
the stem likewise is thicker at the base, and tapers regularly to the point; the surface
is deeply sculptured with fine longitudinal lines. 7

Affinities and differences.—This species very much resembles Hemipedina Bechet, but
the imperfect condition of the test of that species renders a comparison of this part of the
body with that of 7. Bowerbanku impossible; the spines, however, of the two species,
which are drawn side by side on the plate (figs. 1 4, 2c), show that these two nearly allied
forms from the same bed are, however, specifically distinct, the spine of H. Becher being
longer and more slender than that of A. Bowerbanki, although the test to which it was
attached is smaller; the milled ring in H. Becher is narrower and more prominent, and
the head more conical, than the homologous parts in H. Bowerbanki. It resembles
Diadema seriale, Leymerie (P\. IX, fig. 3 a, 4), from the Inferior Lias of France, which I
have copied * for the purpose of comparison, and likewise to show the probable form of our
Lias specimen. In this very rare urchin, the primary tubercles are larger (fig. 3 0), and
there are only two, nearly of the same size, abreast on each plate; the scrobicular circles
are more complete (fig. 3 4), and the granulations fewer but more numerous; the pores
are much closer set together in the zones, there being twelve pairs opposite each inter-
ambulacral plate.

Locality and Stratigraphical position—Hemipedina Bowerbankiu was collected from
the marly beds of the Lower Lias, at Lyme Regis, by Mr. Bowerbank, to whose magni-
ficent collection it belongs. I have not ascertained the precise Ammonital zone in which —
this urchin was found. I have great pleasure in dedicating this species to our amiable,
excellent, and indefatigable Secretary, to whose great and continued exertions, through a
series of years, the Paleeontographical Society owes much of its present success.

Hemipepina Jarpinu, Wright. Pl. IX, fig. 4 a, 4, ¢, d, e, f.

HEMIPEDINA JarpDINII. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 96.

Test small, much depressed; ambulacral areas wide, with two rows of marginal

* «Mémoires de la Société Géologique de France,’ t. ii, p. 330, pl. 24, fig. 1, 1839.

FROM THE LIAS. 147

tubercles, which extend from the peristome to the disc; inter-ambulacral areas with two
rows of tubercles set near the poriferous zones, eleven to twelve in each row; a delicate
circle of small granules around each, and a naked space in the centre of the miliary zone ;
mouth opening small, peristome decagonal; base exhibiting very regular radii of tuber-
cular rows.

Dimensions.—Height, one fifth of an inch; transverse diameter, half an inch.

Description —The test of this beautiful little Diadem is small, circular, and depressed
on the upper and under surfaces ; the ambulacral areas are narrow, with two rows of small
tubercles (fig. 4d) set alternately on the sides of the area, close to the poriferous zones
(fig. 4 g); a line of granules occupies the course of the central suture, and additional
granules fill up the space between that line and the pores (fig. 4 g); there are from twelve
to fourteen tubercles in each row ; about one third the size of those of the inter-ambulacra,
but much smaller in proportion in the upper part of the area (fig. 4 d@) ; the zones are
narrow and straight throughout ; the septa forming slight papillze on their surface ; the pores
are very small, and there are four pairs of holes opposite each of the large plates.

The inter-ambulacral areas are nearly three times the width of the ambulacral; they
have two rows of primary tubercles, about ten or eleven in each row; the tubercles occupy
the centre of the plates (fig. 4 g); the boss is prominent, the tubercle small, and the areola
not well defined ; on each side of the tubercle there are two rows of granules, the inner of
which forms a circle around the boss (fig. 4 g); the miliary zone is wide (fig. 4 /), and
filled with the granules just described; imterspersed among them are several which pass
into the condition of minute tubercles, bemg raised on miniature bosses, and having their
surface perforated. On the upper part of the area the granules disappear from the centre,
leaving a portion of the plates naked (fig. 4 7) ; as the granules are disposed with much
regularity, the test of this species has a highly ornamented appearance (fig. 4 d, e, f).

The base is concave, and the mouth opening, which is less than half the diameter of
the shell, is situated in a depression ; the peristome is decagonal, the ambulacral being
larger than the inter-ambulacral lobes: as the primary tubercles of the inter-ambulacra are
set close together at the base, they form prominent tuberculated radu (fig. 4 e) in this
region.

The discal opening is small, but the plates are absent.

Affinities and differences.—This species resembles H. Htheridgiz, but it is a smaller
and more depressed form; the tubercles of the ambulacra are larger in size and fewer in
number; and those of the inter-ambulacra want the well-defined areolas around them,
seen in the primary tubercles of H. Htherzdgii (fig. 5g). The discal opening is likewise
a much smaller aperture in H, Jardini than in H. Ltheridgii.

148 HEMIPEDINA.

Locality and Stratigraphical position.—This beautiful little Diadem has been found in
the Marlstone of Bredon, Alderton, and Dumbleton Hills, Gloucestershire, and in the
same rock at Ilminster, Somersetshire. It is everywhere a very rare form. I dedicate
this species to my friend Sir William Jardine, Bart., of Jardine Hall, Dumfrieshire,
author of a magnificent work on the ‘ Ichnology of Annandale,’ and other valuable treatises
on different branches of Natural History.

Hemipepina Erueripen, Wright. Pl. IX, fig. 5 a, 6, ¢, d, e, f, g.

Prepina ETHERIDGII. Wright, Annals and Magazine of Natural History, 2d series,
vol. xii, p. 315, pl. 11, fig. 5 a—e.
= = Morris, British Fossils, 2d edition. Additional species.
Hyroprapema Hrueriperr. Desor, Synopsis des Echinides Fossiles, p. 61.

‘Test circular, depressed; ambulacral areas with from six to eight small perforate
tubercles at their base, and a double row of small granules on their upper surface; the
inter-ambulacral areas with primary tubercles only, the areolas of which are surrounded
by regular circles of granules; pedal pores not numerous, arranged in nearly a single
file, with a slight elevation between the two pores of each pair; apical disc large; ovarial
plates leaf-hke ; mouth opening small.

Dimensions.— Height, one quarter of an inch ; transverse diameter, half an inch.

Description —This pretty little urchin has a circular outline in the young state, which
in larger specimens inclines towards a pentagonal form; the base is flattened, and the
upper surface is much depressed (fig. 5 ¢). ‘The ambulacral areas are straight and narrow
(fig. 5 d, e, f); they have from six to eight small perforated tubercles at thew base
(fig. 5 e), and a double row of from twelve to fourteen minute, imperforate granules m
each row on their upper surface (fig. 5 d), which, in form and size, resemble those cover-
ing the other parts of the test (fig. 5 yg); between the pedal pores of each pair is a small
elevation (fig. 5 g); these collectively form a prominent moniliform line, which extends
from the margin of the disc to the mouth opening ; the pores are unigeminal, and disposed
in nearly a single file throughout (fig. 5g). The iter-ambulacral areas are about twice
the width of the ambulacral; the rows of primary tubercles occupying the centre of the
plates have seven or eight tubercles in each row ; they are small in size, and rendered promi-
nent from being raised upon uncrenulated mammillary eminences, the bases of which
are sharply defined, and surrounded by complete circles of small scrobicular granules
(fig. 5g); the regular disposition of these granulations gives an air of decoration to
this beautiful little species, and the entire absence of secondary tubercles from the
areas renders the ornamentation even more complete (fig. 5 d, e, 7). The apical disc

FROM THE INFERIOR OOLITE. 149

is large (fig. 5d); the ovarial plates are widely rhomboidal (fig. 5 d); the oculars
are small and heart-shaped; and the surface of both is covered with minute granules,
nearly as large as those which adorn other parts of the test. The madreporiform tubercle
makes a distinct elevation on the surface of the right antero-lateral plate (fig.5d); the
anal aperture is transversely oblong; the base is flat, the mouth opening small, and
the peristome divided into ten nearly equal-sized lobes ; the spines are unknown.

Afinities and differences.—In its general outline, depressed upper surface, and uni-
geminal pores, this little urchin resembles a Psewdodiadema. From that group, however,
it is distinguished by the rudimentary condition of the ambulacral tubercles, and the
absence of crenulations from the summits of the bosses. It is distinguished from Hemipe-
dina Bakert by having small primary tubercles set more closely together, and in having a
greater number in each row. From Pedina rotata it is known by having unigeminal
pores, the upper surface more depressed, the pedal pores separated by a moniliform line of
granules, and im the absence of secondary tubercles. At a first glance, it has a strong
resemblance to Pseudodiadema Moorezi, but an examination with the lens at once discloses
the points of difference, which are these: the ambulacral areas in Hemipedina Ltheridgii
have imperforate granules on their upper parts, whilst in Psewdodiadema Mooreii they are
perforated tubercles ; the moniliform line between the pedal pores in Hemipedina Ltheridgti
is absent in Pseudodiadema Moorewi ; the mouth opening is likewise much smaller in /emz-
pedina Etheridgit.

Locality and Stratigraphical position.—This species has been found in the Upper
Lias of Gloucestershire, and in the Upper Lias near Ilminster, Somersetshire, associated
with Ammonites (Walcotii) bifrons, Brug.; Ammonites serpentinus, Schloth. ; Ammonites
annulatus, Sow.; and other Upper Liassic forms of Mollusca and Radiata. It is a very
rare urchin, and is seldom found in a good state of preservation. Professor Deslongchamps
has collected the same species in “le Lias supérieur de May et Vontaine—Etoupetour,
Calvados.” I dedicate this species to my friend Robert Etheridge, Esq., .R.S.E., of the
Bristol Museum, who has kindly assisted me in comparing my specimens with the fine
series of Echinoderms under his care, and who has likewise otherwise aided me in the
most friendly manner, in working out the subjects of this Monograph.

B. Species from the Inferior Oolite.

Hemipepina Baxert, Wright. Pl. X, fig. 1 a, 6, ¢, de, f.

PEpINA BakgERI. Wright, Annals and Magazine of Natural History, 2d series,
vol. xiii, p. 312, pl. 11, fig. 4.
HemipiapEMA Bakeri. Desor, Synopsis des Bchinides Fossiles, p. 58.

150 HEMIPEDINA.

Test circular, depressed ; ambulacral areas narrow, with one row of small tubercles,
disposed in a slightly zigzag line, down the centre of the areas; inter-ambulacral areas
broad, with two rows of primary tubercles in the centre of the plates, raised on prominent
bosses; margins of the areolas surrounded by circles of small granules; no secondary
tubercles.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, three fourths
of an inch.

Description.—This rare urchin has the test circular and depressed (fig. 1 4, c); the
ambulacral areas are narrow, about one third the width of the inter-ambulacral; the usual
double row of tubercles in this region is reduced to one row, the tubercles of which are
disposed alternately on the right and left sides of the areas, thereby forming a single zigzag
line down the centre thereof (fig. 1 4, c,d); the tubercles at the equator, and on the
upper surface, are small (fig. 1 4), but there are two or three of a larger size at the base
of the areas (fig. 1 7d); a few granules form imperfect scrobicular crescents round the
narrow areolas (fig. 1 7d). The inter-ambulacral areas are nearly three times the width of
the ambulacral (fig. 1 4); they are adorned with five pairs of primary tubercles, nearly
of a uniform size throughout (fig. 1 6, c,d), raised on prominent bosses, the summits
of ‘which are smooth, ring-like, and without crenulations (fig. 1 d, e) ; circles of small
granules bound the areolar spaces; there are no secondary tubercles, nor any other
sculpture upon the inter-tubercular surface of the plates, so that down the centre of the
areas there is a smooth valley between the primary tubercles (fig. 1 d, c, 6). The apical
disc is well preserved (fig. 1 6, 7); the ovarial plates are of moderate size, and have an
irregular, heptagonal form ; they are covered with a few granules, scattered irregularly over
their surface; the ocular plates are rhomboidal, and have large eye-holes perforated near
the centre (fig. 1 /).

The base is flat (fig. 1 ¢), and the mouth opening small (fig 1 a); the peristome is
divided into ten lobes by shallow notches.

Affinities and differences.—Vhis species differs so much from all its congeners, that it
cannot be mistaken for either of them. Its diagnostic characters consist im the size and
number of the primary tubercles (fig. 1 4), the absence of secondary tubercles, the naked
valley in the centre of the miliary zone (fig. 1 c, 7), the narrowness of the ambulacra, with
the single row of tubercles therein (fig. 1 @).

Locality and Stratigraphical position—I have collected only one specimen of this
singular form in the Pea Grit at Crickiey Hill, and have seen fragments only on the
surface of other fossils, as one or two plates suffice for the determination of this species.
I dedicate this fine urchin to my friend T. Barwick L. Baker, Esq., of Hardwicke Court,
Gloucestershire, the President of the Cotteswold Naturalists’ Club.

FROM THE INFERIOR OOLITE. 151

Hemipepina perrorata, Wright. Pl. X, fig. 2 a, 6, ¢, d, 2, f, 9.

GoNIOPYGUS PERFORATUS. Wright, Annals and Magazine of Natural History, 2d series,
vol. viii, p. 267, pl. 13, fig. 5 a, 0.

HmMIPEDINA PERFORATA. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 98.

Test small, circular, depressed ; ambulacral areas with two rows of small tubercles,
which extend from the peristome to the disc; inter-ambulacral areas with two rows of
tubercles, seven to eight in each row, and three or four secondary-tubercles near the base ;
mouth opening large; peristome decagonal, divided into deep, nearly equal-sized lobes ;
apical disc large, plates much developed.

Dimensions.—Height, one quarter of an inch; transverse diameter, three quarters of
an inch.

Description —tThis little Diadem was first figured and described as Goniopygus
perforatus, at a time when I was ignorant of the true organic characters of the group to
which it belongs. “I have placed this urchin,” I observed, “ provisionally in the genus
Gonvopygus, as it comes nearer to the character of that form than any other. The absence of
crenulations on the mamme, the nearly uniform size of the tubercles, the distinctness with
which they stand out from the test, and a fragment of the angular apical disc 2” situ, seem
to justify the supposition of its being a Goniopygus ; but the perforation of the tubercles
makes the exception, and suggests the query whether the absence of perforations is a
generic or only a sectional character.”* At the time this passage was written I had only
found three imperfect specimens of this species, and the search after more perfect urchins
of the same natural group led to the discovery of several new congeneric forms, and
finally to the establishment of the genus Hemipedina for their reception.

The ambulacral areas are narrow, and carry two rows of small tubercles, which, from
the peristome to the equator, are regularly developed (fig. 2 c); but above the equator they
rapidly diminish in size, and dwindle into small granules in the upper part of the area
(fig. 2 a, 6, 9).

The poriferous zones are narrow and straight, the septa moderately thick, and at
the base of the area the pores fall into triple, oblique pairs (fig. 2 /), but in the upper part
they are strictly unigeminal.

The inter-ambulacral areas are twice and a half the width of the ambulacral, and
furnished with two rows of tubercles, from seven to eight in each row (fig. 2 4, c); the
bosses are prominent, and surrounded by a narrow areola (fig. 2 g, the letter omitted) ;

* © Annals and Magazine of Natural History,’ 2d series, vol. viii, p. 267.

152 HEMIPEDINA.

the spinigerous tubercles are small, and not deeply perforated; they stand out, however,
in a well-defined manner, from the surface of the test, and are very uniform in size
throughout ; a complete circle of granules surrounds each areola (fig. 2 g), and one row of
granules separates the areolas from the zones; the miliary zone is wide (fig. 2 4), and
filled with four rows of round granules, which are very uniform in size, and closely crowded
together (fig. 2 g), thus imparting a granular aspect to the surface ; the upper part of the
centro-sutural line is naked for the space of the two uppermost plates (fig. 2 6).

The apical disc is large (fig. 2 4); the five genital plates have a heptagonal form, and
are nearly all of the same size; they are perforated at some distance from the apex, and in
the centre of each plate is a cluster of small granules (fig. 2 e); the ocular plates are penta-
gonal, and large in proportion to the size of the urchin; they have granules on their
surface, and the eye-hole is perforated at some distance from the margin; the anal opening
is round and central, and the madreporiform body is very small (fig. 2 e).

The base is concave, and the mouth opening, which is situated in a depression, is one
half the diameter of the test; the peristome is decagonal, and divided into nearly equal-
sized lobes.

Affinities and differences.—This species is nearly allied to H. Jardinii and H. Etheridgi,
out is distinguished from both by the structure of the ambulacra, in which the marginal
tubercles are large and well developed at the base of the area (fig. 2.7), but suddenly
diminished in size, or rather reduced to granules, in the upper part of the same (fig. 2 g) ;
whereas in these other two allied forms they are very regularly developed throughout the
area (Pl. IX, fig. 4 d, and fig. 5 d, which compare with Pl. X, fig. 2 4, 9).

Locality and Stratigraphical position.—I collected this species from that remarkable
rock, the Pea Grit, at Crickley Hill. The species must have been tolerably abundant,
although very few specimens are well preserved. Out of a considerable number | have
only obtained two or three in which the structure of the test can be satisfactorily made out.

Hemrprpina TeTRaAGRAMMA, Wright. PI. X, fig. 3 a, 4, ¢, d.

HEMIPEDINA TETRAGRAMMA. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 98.

Test circular and depressed ; ambulacral areas narrow, with two rows of small, nearly
equal-sized tubercles on the margin of the area, extending from the peristome to the disc ;
inter-ambulacral areas with two rows of primary tubercles, about fourteen in each row,
and two rows of secondary tubercles, ten in each row, extending from the peristome nearly

FROM THE INFERIOR OOLITE. 153

to the upper surface; mouth opening small, situated in a depression ; peristome decagonal
and unequally lobed.

Dimensions.—Height, two fifths of an inch; transverse diameter, nine tenths of an
inch.

Description—This beautiful Hemipedina is a very rare form, having only found
one specimen of the species during the many years I have collected from the locality where
it was discovered.

The tubercles of the ambulacra are nearly as large as those of the inter-ambulacra, which
imparts a very regular appearance to the test (fig. 3 4, ¢).

The ambulacral areas are narrow, about one third the width of the inter-ambulacral ;
on the margins are two rows of tubercles, about twenty in each row; they are very
uniform in size, and arranged in a straight line throughout the area (fig. 3 4, c,d); the
bosses abut against the poriferous zones, but they are separated from each other by a deli-
cate, double line of granules, which extends on each side of the central suture (fig. 3 @),
every third granule between the tubercles being larger. The poriferous zones are narrow,
and slightly undulated, in consequence of the ambulacral tubercles being placed so close
to the avenues, without the intervention of any granular space between to prevent the
encroachment of the tubercles on them (fig. 3 4, c, d).

The inter-ambulacral areas are four times as wide as the ambulacral; at the equator,
each of the large plates of these areas has one central primary tubercle, and at its centro-
sutural side, one secondary tubercle, and between the central tubercle and the zones two
rows of granules (fig. 3 7); from the peristome to the equator there are therefore four
rows of tubercles (fig. 4 d, c), but as the secondary tubercles diminish in size above the
equator, and disappear on the upper surface, there are only two rows of tubercles near the
circumference of the apical disc (fig. 3 4); the bosses are not very prominent ; the tubercles
small, the minute granules forming circles around the rudimentary areolas (fig. 3 d) ;
there are fourteen primary tubercles and ten secondary tubercles in each row, and from
four to five pairs of pores in each of the large inter-ambulacral plates.

The base is very concave, and the small mouth opening lies in rather a deep depression ;
unfortunately it is filled with a hard mass of pisolite, which cannot be dislodged without
risk to the shell (fig. 3 ¢).

The discal opening is small, but all the plates of the disc are absent.

Affinities and differences.- -The regularity of the ambulacral tubercles, and the nearly
uniform size they have in both areas, distinguishes this species from its congeners; the
fact that the inter-ambulacra have four tubercles abreast at the equator, forms a good
diagonistic character, and serves to distinguish it from other allied species found with it in

20

154 HEMIPEDINA.

the same rock. Hemipedina perforata and Hemipedina Waterhouse: having two rows, and
Hemipedina Bonet six rows of tubercles in this region.

Locality and Stratigraphical position.—The only specimen I have seen of this species
I collected from the Pea Grit at Crickley Hill, along with Hemipedina perforata, Acrosa-
lenia Lycetiu, Polycyphus Deslongchampsi, and Pseudodiadema depressum.

Hemipepina Waternousel, Wright. Pl. X, fig. 4 a, 4, ¢, d, e.

Hemipepina WaTERHouseEl. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 98.

Test small, pentagonal, rather inflated at the sides; ambulacral areas with two rows of
small tubercles extending from the peristome to the disc; mter-ambulacral areas with two
rows of tubercles, eight in a row ; scrobicular circles neatly defined; mouth opening small ;
apical disc narrow and prominent.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, half an inch.

Description.—This is a small, pentagonal, inflated species, having the ambulacral areas
with two rows of tubercles, nearly as large as those of the inter-ambulacral ; there are from
twelve to thirteen tubercles in each row, which are placed further apart than those of
HT. tetragramma, each tubercle being surrounded by small, scattered granules (fig. 4 c¢, e) ;
the poriferous zones are narrow and straight (fig. 4 e), and the septa are slightly elevated
on the surface; there are four pairs of pores opposite each of the large plates.

The inter-ambulacral areas are not quite twice the width of the ambulacral; they are oc-
cupied by two rows of primary tubercles, about nine in each row, which have slightly elevated
bosses, surmounted by small tubercles; the base of the boss is closely encircled by small
granules (fig. 4 e), which form complete scrobicular circles around them; each plate has
one row of granules between the tubercles and the zones, and two rows of granules between
the tubercles and centro-sutural line (fig. 4 e).

‘The apical disc is well preserved in both my specimens (fig. 44, 7); the genital
plates have a heptagonal form, the largest side being placed towards the anal opening ;
they are perforated at a short distance from the apex, and two or three granules are
developed on the surface; the right antero-lateral plate is a little larger than the others,
and supports, as usual, a small, spongy, madreporiform body ; the ocular plates are small
and pentagonal; the holes are perforated near the centre of each; the disc forms a slight,
ring-like prominence at the vertex of the test, and the anal opening is circular.

FROM THE INFERIOR OOLITE. 155

The base is flattened, but the mouth opening is unfortunately concealed in the only
two specimens I have found.

Affinities and differences—I\ regarded this urchin, at first sight, as a young form of
H. tetragramma, but the spaced-out arrangement of the ambulacral tubercles, the inflation
of the sides of the test, and the presence of only two rows of tubercles in the inter-
ambulacra, show that it is quite distinct from that species. It is so entirely different from
H. perforatus and H. Bakeri, that it cannot be mistaken for either of them.

Locality and Stratigraphical position —I1 collected this urchin in the Pea Grit at
Crickley Hill, with the former. It must be rare, as I only know two examples of the
species, which I dedicate to my friend G. R. Waterhouse, Hsq., F.Z.S., of the British
Museum, well known by his valuable contributions to zoological literature, and by the
kindness and urbanity of his manner to all who seek information in that department
of the great national collection committed to his care.

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FROM THE INFERIOR OOLITE. 155

The base is flattened, but the mouth opening is unfortunately concealed in the only
two specimens I have found.

Affinities and differences.—I regarded this urchin, at first sight, as a young form of
H. tetragramma, but the spaced-out arrangement of the ambulacral tubercles, the inflation
of the sides of the test, and the presence of only two rows of tubercles in the inter-
ambulacra, show that it is quite distinct from that species. It is so entirely different from
H. perforatus and H. Bakeri, that it cannot be mistaken for either of them.

Locality and Stratigraphical position.—I collected this urchin in the Pea Grit at
Crickley Hill, with the former. It must be rare, as I only know two examples of the
species, which I dedicate to my friend G. R. Waterhouse, Esq., F.Z.S., of the British
Museum, well known for his valuable contributions to zoological literature, and by the
kindness and urbanity of his manner to all who seek information in that department
of the great national collection committed to his care.

Hemipepina Bonz, Wright. Pl. X, fig. 5 a, 4, ¢, d.

Hemrpepina Bonet. Wright, Annals and Magazine of Natural History, 2d series, vol. xvi,
p- 98.
— — Woodward, Memoirs of the Geological Survey, Decade v, ‘‘ notes on

Echinopsis.”’

Test small, pentagonal, depressed; ambulacral areas with two marginal rows of
close-set tubercles ; inter-ambulacral areas with two entire central rows, and four shorter
lateral rows of tubercles, which extend only to the equator ; the tubercles of both areas are
small and nearly of the same size; base concave; mouth opening of moderate width;
peristome nearly equally decagonal.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, eight tenths
of an inch.

Description.—This small pentagonal depressed urchin has the minute tubercles of both
areas nearly of the same size (fig. 5 4, c); the ambulacral areas are about one third
the width of the inter-ambulacral; they have two rows of tubercles, from eighteen to
twenty in each row, set on the margin of the areas (fig. 5 c, d), with incomplete circlets
of small granules surrounding them (fig. 5 d), except on their zonal side, where

they are absent; the poriferous zones are narrow, straight, and distinctly unigeminal
21

156 HEMIPEDINA.

throughout, and there are three pairs of pores opposite each of the inter-ambulacral plates
(fig. 5 d).

The inter-ambulacral areas are three times the width of the ambulacral; at the equator
there are six rows of tubercles (fig. 5 d), nearly of the same size, but only the central row
of each column extends from the peristome to the disc, at the base this row is large and
very conspicuous (fig. 5 c), at the equator the tubercles are a little larger than
the lateral rows, and from the equator upwards (fig. 5 4), they alone occupy the upper
surface of the shell, of the two lateral rows, that on the zonal side is the shortest ;
there are from sixteen to eighteen tubercles in each of the central rows, and from
eight to ten in the lateral rows; the areolas are surrounded by small granules, which
form a delicate network on the surface of the plates, (fig. 5 d).

The apical disc is absent in all the specimens I have seen, it has an oblong form, and
extends further into the single inter-ambulacrum than the other areas (fig. 5 c).

The base is slightly concave (fig. 5 c), and the tubercles are much larger in this region
than on the upper surface (fig. 5 6); the mouth opening is large, and the peristome is
divided into nearly equal sized lobes.

Affinities and differences.—The pentagonal form of this species, with its elongated
opening for the apical disc, reminds me of some young Pygasters, which occur with it in
the same rock ; but the size and arrangement of the tubercles, its depressed form, and
small discal opening, serve to distinguish it from them; how far a greater number
of specimens, especially if the apical disc were preserved, would lead me to modify my
opinion as to its generic position, it is impossible to say; I have, therefore, provisionally
placed this beautiful little urchin with the Hemipedinas, the characters just enumerated
being sufficient to show in what it differs from its congeners.

Locality and Stratigraphical position.—t have collected this urchin from the Pea grit,
Inferior Oolite, of Crickley Hill, associated with the preceding species from the same bed,
where it is rare. I dedicate this species to Mr. C. R. Bone, whose beautiful figures of
Hchinoderms, have given such a lasting value to the plates which accompany this

Monograph.

C. Species from the Great Oolite and Cornbrash.

Hemirepina Davipsoni, Wright. Pl. XI, fig. 6 a, 4, ¢, d.

Hmmirepina Davipsonz. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 99.
Woodward, Memoirs of the Geological Survey, Decade v, ‘‘ Notes

on Echinopsis.”

FROM THE GREAT OOLITE. 157

Test circular, much depressed, ambulacral areas with two marginal rows of tubercles
very regularly arranged throughout the area; inter-ambulacral areas wide, with two
central rows of primary tubercles, and four lateral rows of secondary tubercles ; poriferous
zones narrow, and straight ; under surface of the test crowded with tubercles, upper surface
deficient in tubercles, base concave, mouth opening small, peristome unequally deca-
gonal.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, one inch.

Description—I found this urchin about twelve years ago in the sandy beds of the
Great Oolite, at Minchmhampton ; and although I have searched diligently since in the
same locality for other specimens, I have failed. ‘The test is not in very good preservation,
but it is still sufficiently so to enable me to describe its characters ; the shell is thin, cir-
cular, and much depressed ; the ambulacral areas are straight and narrow (fig. 6 a), being
less than one third the width of the imter-ambulacral, on their margins are two rows of
tubercles (fig. 6 7) in each row, which are very uniform in size throughout, corresponding
with a greater uniformity in the width of the area than in some other species; the pori-
ferous zones are narrow ; the pores unigeminal throughout (fig. 6 a), except at the base,
where three additional pairs are crowded in; there are four pairs of pores opposite each
inter-ambulacral plate.

The inter-ambulacral areas are three times the width of the ambulacral; each of the
elongated pentagonal plates composing the two columns has one central primary
tubercle (fig. 6 7); these tubercles form an uninterrupted row, which extends from the
peristome to the disc; besides the central row, the plates between the peristome and
equator have two lateral rows of smaller secondary tubercles (fig. 6 d), disposed on
each side of the primary one, so that at the equator the inter-ambulacra have six rows
of tubercles abreast; above that line, however, the secondary series disappear, and on
the upper surface of the test the two primary rows alone exist (fig. 6 4); the primary
tubercles are very uniform in size throughout, but the secondaries vary much in magnitude
(fig. 6 d).

The base is flat, the mouth opening is small, beg about one third the diameter of the
shell, the peristome is decagonal and nearly equal-lobed (fig. 6 c).

Afinities and differences.—This species resembles Hemipedina tetragramma, but the
ambulacral tubercles are larger and less numerous ; the poriferous zones are narrower, and
the pores more strictly unigeminal; the inter-ambulacral areas are wider, and _ less
ornamented with granules and tubercles; the secondary tubercles between the pori-
ferous zones and the primary row (fig. 6 d),is absent in Hemipedina tetragramma. PI. X,
fig. 3 d, the aperture for the apical disc is likewise much larger in Hemipedina Davidsoni.

158 HEMIPEDINA.

Locality and Stratigraphical position.—tI collected this urchin from the sandy beds of
the Great Oolite, at Minchinhampton Common, where it is extremely rare; the specimen
figured is the only one I know. I dedicate this species to my esteemed friend, Thomas
Davidson, Hsq., author of the ‘ Monographs on the Fossil Brachiopoda of Great Britain.’

Hemirepina Woopwarpl, Wright. Pl. XII, fig. 7 a, 4, ¢, d.

HemMIPepIna Woopwarpi. Wright, Annals and Magazine of Natural History, 2nd series,
vol. xvi, p. 99.
— _— Woodward, Memoirs of the Geological Survey, Decade v, “‘ Notes
on Echinopsis.”

Test small, circular, and much depressed; ambulacral areas narrow, with two rows of
small tubercles which extend from the base to the equator, and diminish to small granules
in the upper part of the areas; imter-ambulacral areas with two rows of primary tubercles,
eight in each row, and two rows of secondary tubercles, three to four in each row, which
scarcely reach the equator ; the miliary zone is wide on the upper surface and filled with
numerous close-set granulations ; apical disc large, genital plates much developed ; mouth
opening small, peristome decagonal and nearly equal lobed.

Dimensions.—Small specimen, height seven twentieths of an inch ; transverse diameter
thirteen twentieths of an inch.

Description —tThis urchin belongs to the type of Hemipedinas, which have two rows
of primary tubercles, with a wide granulated miliary zone between them on the upper
surface of the inter-ambulacral areas; although undescribed, this species has been long
known, as there is a fragment of it, collected by Dr. William Smith, from the Cornbrash,
which forms part of his collection now in the British Museum.

The ambulacral areas are straight and narrow (fig. 7 a), on their lower half, or from
the peristome to above the equator (fig. 7 c), there are from nine to eleven pairs of
tubercles according to the size of the specimen ; these tubercles are perforated, and raised
on bosses with semicircles of minute granules around them (fig. 7 d); from about the
equator to the apical disc the tubercles degenerate into granules (fig. 7 4), so that the
lower half of the area possesses tubercles, whilst the upper half is occupied by granules ;
the poriferous zones are narrow, and straight; the pores, which are strictly unigeminal,
are small (fig. 7 d), and there are five pairs of pores opposite each of the inter-ambulacral
plates ; the septa have slightly raised eminences on the surface.

‘The imter-ambulacral areas are four times the width of the ambulacral, they have two
entire rows of primary tubercles, and two short rows of secondary tubercles; each plate,
between the peristome and the equator, has one large tubercle on its zonal side, and one

FROM THE CORNBRASH. 159

secondary tubercle on its centro-sutural side (fig. 7 @), so that from the base to the
equator there are two rows of primary and two rows of secondary tubercles (fig. 7 a, ©),
between the equator and the apical disc the secondary tubercles are absent, and the wide
miliary zone is occupied by several rows of small close-set granules (fig. 7 a, 4).
According to the age of the test, there are from eight to ten primary tubercles and from
five to six secondary tubercles in each row.

The apical disc is large (fig. 7 4), the heptagonal genital plates are much expanded and
perforated near their centre, the ocular plates are proportionately large, and form crescentic
arches over the apices of the ambulacra; the surface of both the genital and ocular plates
is covered with small granules, the anal opening is central, and the rim of the aperture
forms a slight prominence at the vertex.

The mouth opening is small (fig. 7 c), the peristome is decagonal, and notched into
nearly equal sized lobes; from the development of the tubercles at the base of the test,
this region presents a much more tuberculated appearance than the upper surface, where
the granules of the ambulacra, and the wide miliary zone of the inter-ambulacra (fig. 7 4),
form a striking contrast to the tubercles which adorn the lower part of the same divisions
of the test at the base (fig. 7 ¢ and d).

Affinities and differences——In the semi-tuberculous character of the ambulacra this
species resembles Hemipedina perforata, Pl. X, fig. 2, and Hemipedina tuberculosa,
Pl. XI, fig. 2, but it is distinguished from both by having secondary tubercles
in the inter-ambulacra, which are absent in these species. It resembles Hemipedina
Davidsoni, Pl. XII, fig. 6, and Hemipedina tetragramma, P\. X, fig. 3, in possessing
secondary tubercles in the inter-ambulacra, but the disappearance of the marginal tubercles
from the upper parts of the area shows how distinct it is from these congeneric forms.

Locality and Stratigraphical position—This species was collected many years ago by
Dr. William Smith, and is probably the specimen from the Cornbrash of Melbury, referred
to in his “ Strata identified by organized fossils.”

My small specimen came from the Cornbrash near Trowbridge, Wilts ; the same species
has been collected in the Cornbrash near Boulogne-sur-Mer.

I dedicate this species to my excellent friend S. P. Woodward, Esq., of the British
Museum, as a mark of respect and gratitude for the trouble and interest he has taken in

the success of this work.

Hemipepina microeramMa, Wright, nov. sp. Pl. XII, fig. 4 a, 4, e.

Test subpentagonal, depressed ; ambulacral areas wide, with four rows of tubercles ;
poriferous zones narrow and straight ; inter-ambulacral areas with eight rows of tubercles

160 HEMIPEDINA.

at the equator, diminishing above to six, four, and two rows; tubercles of both areas very
small and nearly of the same size; sides rounded, upper and under surfaces much
depressed.

Dimensions.—Height, eleven twentieths of an inch; transverse diameter, one inch and

seven tenths.

Description —The only specimen I know of this species is the one now figured ;
unfortunately the surface of the test has been rubbed smooth in some places, and distorted
and broken in others, so that only an imperfect description of this interesting form can be
given.

The ambulacral areas are wide and straight, and retain a very uniform width through-
out; at the equator they have four rows of small tubercles (fig. 4 c), the two marginal
rows are the most regular, as regards size and arrangement, there being about twenty-five
tubercles m each row, the two inner rows commence below the equator and extend two
thirds of the distance between the equator and the apical disc ; they are smaller in size and
not so regularly arranged as the outer rows; each row contaims from ten to twelve
tubercles; between these four rows of tubercles small granules are very regularly inter-
spersed. The poriferous zones are perfectly straight and very narrow, and the pores are
small and unigeminal throughout; there are five pairs of pores opposite each of the
inter-ambulacral plates. The inter-ambulacral areas are about twice and a half as wide as
the ambulacral; each plate at the equator supports four tubercles (fig. 4 c), which are so
disposed on the consecutive plates of the columns that they form a series of oblique
rows (fig. 4 4); there are sixteen plates in each column, and in the upper part of the areas
the number of tubercles gradually diminishes to three, four, and two on each (fig. 4 a).
The tubercles of both areas are very small, and nearly of the same size; their bosses are
flat, and the narrow areolas are surrounded by a circle of small scorbicular granules,
which imparts an ornamental appearance to the test. |

The space for the apical disc is large, but as the margin of the aperture is fractured
no certain estimate can be made of the probable size of the disc.

The base is concave, and the mouth opening so much concealed by adhering
matrix that its form cannot be accurately made out; enough, however, is exposed, to
show that the peristome is decagonal and formed of unequal sized lobes.

Afinities and Differences.—This urchin belongs to the type of Hemipedinas with
several rows of equal sized tubercles at the equator; in the number and smallness of its
tubercles it is so unlike all its present known congeners that it cannot be mistaken for
either of them. In the width of its ambulacra, and in the mode of distribution of the

tubercles in oblique rows, it resembles the Pygasters.

FROM 'THE CORAL RAG. 161

Locality and Stratigraphical position.—It appears to have been collected from the
Cornbrash of Northamptonshire; but as the history of the specimen is unknown, this
is only conjecture. It forms part of the late Miss Baker’s (Northampton) Collection in the
British Museum.

D. Species from the Coral Rag.

Hxmipepina Marcuamensis. Wright. Pl. XI, fig. 1 a, 0.

Hemrpepina Marcuamensis. Wright, Annals and Magazine of Natural History, 2nd series,
vol. xvi, p. 197. :
— — Woodward, Memoirs of the Geological Survey, Decade vy,
** Notes on Echinopsis.”’

Test large, circular, and depressed; ambulacral areas narrow, with two rows of
marginal tubercles, nearly as large as those of the inter-ambulacral; extending
regularly, without interruption, from the peristome to the apical disc, and separated by a
zig-zag line of small granules, the areas retaining a nearly uniform width throughout ;
poriferous zones narrow, forming a slightly waved line, every three pairs of pores being set
obliquely in the line of the zones; imter-ambulacral areas four times the width of the
ambulacral, with eight rows of tubercles at the equator, each tubercular plate supporting
four nearly equal sized tubercles abreast; mouth opening large, peristome unequally

decagonal.

Dimensions.—Transverse diameter, two inches and nine tenths; height, one inch
and three tenths.

Description.—In the present state of our knowledge, it would be premature to propose
subgenera of the remarkable group of urchins now under consideration, but it is evident
that we have at least two sections of the genus Hemipedina, among its forms now known.
Ist, those with two rows of primary tubercles, a wide miliary zone, and sometimes
rows of secondary tubercles in the inter-ambulacral areas. 2d, those with four, six,
eight, or even ten rows of nearly equal sized tubercles abreast, in the same region of the
test ; Hemipedina Woodwardi, and Hemipedina tuberculosa, are types of the first section ;
Hemipedina Marchamensis, and Hemipedina Bouchard, are types of the second. At
first sight, it seems difficult to believe that the two urchins, figuredin Pl. XI, fig. 1 and 2,
belong to the same genus, but a careful analysis of their structure does ,not afford any
permanent characters for generic separation.

A parallel case is afforded by the genus Psewdodiadema, where one section has two

162 HEMIPEDINA.

rows of primary tubercles in the inter-ambulacra, and another has four rows of primary
tubercles in the same region of the test.

The section of which Hemzpedina Marchamensis is the type, appears to belong to the
middle and upper division of the Oolites, as the only species exhibiting these hexa-
grammous and octogrammous characters, are found in the Calcareous Grit, Coral Rag,
and Kimmeridge Clay.

The test of Hemipedina Marchamensis is large, nearly perfectly circular at the equator,
and depressed on the upper surface ; it appears to have had a hemispherical form, but
unfortunately the upper portion of the body is fractured, and the outlme is traced with
difficulty, in consequence of adhering matrix. The ambulacral areas are narrow (fig. 1 a),
with two marginal rows of tubercles, closely placed together, along the sutural line, two
rows of granules separate the tubercles (fig. 1 4), and transverse branches from these
bound the areolas; the poriferous zones, which closely embrace the bosses, are slightly
undulated (fig. 1 4), from the pores being grouped in threes, the septa are thin and elevated
on the surface, and there are five pairs of pores opposite each large plate (fig. 1 4).

The inter-ambulacral areas are four times as wide as the ambulacral (fig. 1 a); they
are crowded throughout with numerous rows of nearly equal sized tubercles, which, added
to the regular rows in the ambulacra, impart a most remarkable tuberculous character to
this urchin; the inter-ambulacral plates near the equator (fig. 1 6), have three
large tubercles placed on the same line, and one or two smaller tubercles on their zonal
sides, so that at the equator there are eight rows of tubercles; the bosses are large and
prominent, and the tubercles are small and deeply perforated ; estimating the number of
plates in each column at about twenty, each area would contain 20 x 2=40 x 4=160
tubercles, which multiplied by five areas, gives 800 tubercles in the inter-ambulacral areas
of this species; the areolas are narrow and superficial, and surrounded by a complete
circle of small granules (fig. 1 4), the tubercles of the imter-ambulacra are a little larger
than those of the armbulacra.

The base of the test, which is well preserved, is slightly convex at the sides, and de-
pressed at the centre (fig. 1 a); the regular distribution of the numerous tubercles gives
this region of the shell a highly ornamented appearance, which is admirably represented in
(fig. 1 a), the mouth opening is not quite one third the diameter of the body, the peristome
is unequally decagonal, the ambulacral lobes being the largest ; the jaws are large and
powerful, and project from the mouth with the teeth “in situ.”

The upper surface of the test is unfortunately absent, the specimen having been de-
tached from the rock, without due care having been taken to preserve the part to which it
adhered, and which evidently contained the other portion of the shell.

Affinities and differences.—This splendid urchin resembles Hemzpedina Corallina,
from the Coral Rag, in the number of the tubercles developed on the inter-ambulacral plates,

FROM THE CORAL RAG. 163

but is distinguished from it by the greater size they attain in Hemipedina Marchamensis.
It resembles, likewise, Hemipedina Bouchardii, from the Kimmeridge Clay of Boulogne-
sur-Mer, but as that species has ten small tubercles on the inter-ambulacral areas, our
species, which has only eight, is distinct from it, whilst they both belong to that section of
the genus with numerous tubercles ranged on the same line on the plates.

Locality and Stratigraphical position—This species was collected from the lower
Calcareous Grit of Marcham, Berks, and belongs to the collection of the Hon. R. Marsham,
who kindly communicated it for publication.

Hemirepina Coratuina, Wright, nov. sp. Pl. XII, fig. 1 @, 6, ¢, d.

Test large, form unknown; ambulacral areas narrow, with two marginal rows of
tubercles ; inter-ambulacral areas wide, equatorial plates with five or six tubercles on each ;
spmes long and slender, stem nearly a uniform diameter and covered with fine,
close-set longitudinal lines, tubercles of both areas small and nearly of the same size.

Description —The diagnosis of this species is most imperfect, as I only know the
fragments of the test I have figured, which doubtless formed portions of large urchins ;
fig. 1 @ was collected by Mr. Bean, from the Coralline Oolite of Malton; the ambulacral
areas of this specimen have two marginal rows of small tubercles placed rather wide
apart.

The inter-ambulacral areas are three times the width of the ambulacral. On the large
equatorial plates (fig. 1 4, c), there are four rows of primary tubercles abreast, with two
smaller secondary tubercles at the zonal side of the plates (fig. 1 c), which would give
eight rows of tubercles in the inter-ambulacral areas; the areolas are wide and smooth, and
surrounded by circles of small granules (fig. 1 4, c).

The mouth opening is large, and the jaws, which are preserved in situ, are powerful,
and armed with strong teeth (fig. 1 a).

The spines are long and slender; the head is short and stout (fig. 1 d); the stem
tapers very little; the milled ring is prominent, and on it and on the surface of the stem
are numerous fine close-set longitudinal lines.

Afinities and differences——In the number of its tubercles in the inter-ambulacra, this
species resembles Memipedina Marchamensis (Pl. XI, fig. 1), but they are much smaller
in size, have much smaller bosses, and wider and smoother areolas than in that species ;
unfortunately, the fragments admit of no further comparison.

Locality and Stratigraphical position—tThe fragment (fig. 1 a) was the only portion
22

164 HEMIPEDINA.

Mr. Bean ever saw after collecting many years from the Coralline Oolite of Malton, York-
shire, and fragment (fig. 1 4), is the only portion showing the external surface of the
plates I have obtained from the Coral Rag of Calne, Wilts; from this locality, however,
T have seen the interior of a large Hemzipedina which was upwards of three inches in
diameter, having the jaws “‘in situ,” but as the external surface of all the plates was con-
cealed, the species was indeterminable, it most probably however belonged to this species,
as the figure of the plates was the same as those in (fig. 1 J, c).

HEMIPEDINA TUBERCULOSA, Wright. Pl. XI, fig. 2 a, 6, ¢, d, e, f.

HEMIPEDINA TUBERCULOSA. Wright, Annals and Magazine of Natural History, 2nd series,
vol. xvi, p. 99.
— — Woodward, Memoirs of the Geological Survey, Decade v,
“* Notes on Hchinopsis.”’
— _ Desor, Synopsis des Hchinides Fossiles, p. 60.

Test hemispherical, depressed; ambulacral areas narrow, with two rows of semi-
tubercles at the base, which extend as high as the equator; upper part of the areas with
two rows of very small marginal granules ; interambulacral areas with two rows of primary
tubercles set on prominent bosses, the areolas surrounded by circles of coarse scrobicular
granules ; between the peristome and the equator there are two rows of small secondary
tubercles on the zonal side of the plates, and several at the base of the rows; the miliary
zone is wide, and covered with coarse granules, the sutural lines are naked above; mouth
opening large, the peristome very unequally lobed, the ambulacral being double the size
of the inter-ambulacral lobes; anal opening large; spines moderately stout and covered
with longitudinal lines.

Dimensions. —Height, seven tenths of an inch; transverse diameter, one inch and one
fifth of an inch.

Description.—This new and beautiful urchin was only discovered a few months
ago in the Coral Rag of Wiltshire. ‘The original type specimen, belonging to the British
Museum, has so much of the matrix adhering to its upper surface that its true form is
concealed ; the discovery, however, of the fine specimen I have figured, now enables me
to give very full details of its structure, mcluding even the spines.

The ambulacral areas are narrow ; their basal half is enlarged, and filled with two rows
of semi-tubercles gradually increasing in size from the peristome to the uppermost tubercle
(fig. 2 4, c, d), like the semi-tubercles of the same region in the genus Hemicrdaris ; there
are eight tubercles in each row (fig. 2 e) which alternate with only a solitary granule at

FROM THE CORAL RAG. 165

the angles between them (fig. 2d); beyond the semi-tubercles the area becomes con-
tracted, and the upper half of the space is filled with two marginal rows of small
granules from sixteen to eighteen in each row (fig. 2c, @), the very great difference
between the structure of the inferior and superior parts of the ambulacral areas forms a
remarkable feature in the diagnosis of this urchin.

The poriferous zones are slightly undulated (fig. 2 c, d); from the apical disc to the
fourth pair of semi-tubercles the pores are unigeminal; but from this point to the peristome
the area contracts and the zones expand to fill up the increase of space at the base, in this
region (fig. 2 4), the pores fall into triple oblique pairs; between the pores, forming a pair,
the septa form an elevated moniliform line (fig. 2 d); and there are five pairs of pores
opposite each inter-ambulacral plate.

The inter-ambulacral areas are twice and a half the width of the ambulacral
(fig. 2 a, ¢); they are filled with two rows of primary tubercles, eight tubercles in each
row, which gradually increase in size from the peristome to the equator (fig. 2 c), and
then as gradually diminish as they approach the apical disc (fig. 2 a); the mammillary
bosses of these tubercles, especially those about the centre of the rows, are large and
prominent (fig. 2 7); their summits are broad and smooth (fig. 2 ¢, e), and the areolas
are not wide (fig. 2 e), there are two rows of secondary tubercles on the zonal side of the
primaries (fig. 2 4), which extend from the peristome to near the equator, and a few
others, about six, at the basal portion of the centro-sutural region (fig. 2 6, ¢), the miliary
zone 1s broad (fig. 2 a), and filled with from four to six rows of coarse, unequal-sized
granules, some of them even assuming the form of minute tubercles (fig. 2 d); the
areolas are surrounded by these granules, which form complete scrobicular circles in the
three uppermost tubercles (fig. 2 a), and incomplete circles in the lower ones (fig. 2 d),
the sutural lines in the centro-sutural region are very distinctly marked.

The mouth opening is large, being one half the diameter of the test at the equator,
the peristome is very unequally lobed, the ambulacral lobes being double the size of the
inter-ambulacral.

The apical disc is absent, but as the opening is very large it indicates a great develop-
ment of the plates composing it, which, in the only four specimens I at present know,
are entirely absent.

Two of the spines are fortunately preserved in our specimen (fig. 2 a, 7); they are
cylindrical, with a prominent milled ring, and a small head (fig. 2,7), the surface of the
stem is covered with longitudinal lines; the stem is unfortunately broken, so that its length
is not known.

Affinities and differences.—This urchin might easily be mistaken for a Hemicidaris,
like that genus it possesses two rows of semi-tubercles at the base of the ambulacra,
and two rows of primary tubercles in the inter-ambulacra; but the absence of crenulations

166 HEMIPEDINA.

from the summits of the bosses, the presence of secondary tubercles in the inter-ambulacra,
and the great size of the discal opening, are characters which serve to distinguish it from
Hemicidaris.

It forms the best type of that section of the genus, which has two rows of tubercles
in the inter-ambulacra, with a wide miliary zone; the contrast between the two
sections of the group is strikingly exemplified by comparing figures 1 and 2 of Plate XI.
where Hemipedina Marchamensis, and Henipedina tuberculosa are drawn side by side.

In the structure of the ambulacral areas, with tubercles below, and granules above, and
with two rows of tubercles in the inter-ambulacra, this species resembles MHemipedina
Woodward, but the tubercles in Hemipedina tuberculosa are much larger, the granules
are more developed, and it is a higher and more inflated form than the Cornbrash species.

Our urchin very much resembles the mould in plaster named Hemicidaris depressa,
Agassiz, ““X 55, R44. Cat. Syst. p. 8. Espéce plate, subconique, 4 ambulacres non
flexueux” from the Forest Marble, of Ranville,* but it is impossible to make a critical
comparison of that form with Hemipedina tuberculosa, without a typical specimen; at
present I know of no other form for which this beautiful urchin could be mistaken.

Locality and Stratigraphical position.—This species has been found only in the Coral
Rag of Wiltshire, by Mr. William Buy; the fine specimen I have figured, was discovered
by him near Lyneham ; it is a very rare form, as that able and accurate collector has only
found three or four specimens of the species.

H. Species from the Kammeridge Clay.
Hemirepina Morrist, Pl. XII, fig. 2 a, 4, ¢, d, e.

Hemipepina Morrisii. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 198.
— — Woodward, Memoirs of the Geological Survey, Decade v, “ Notes
on Echinopsis.”

Form and size unknown ; test small; ambulacral areas with two rows of prominent
marginal tubercles ; poriferous zones slightly waved ; inter-ambulacral areas with four rows

of prominent tubercles at the equator, nearly on the same line, surrounded by incomplete
circlets of granules.

Description.—The only portion of this urchin I have seen, is that now figured;

Ske 6 > yoe . 7 i 6
Annales des Sciences Naturelles, 3°™° série, tome vi, p. 338, Agassiz and Desor. Catalogue raisonné
4 = je
des Wechinides,

FROM THE KIMMERIDGE CLAY. 167

the ambulacral areas are moderately wide, they have two rows of regular, prominent, mar-
ginal tubercles, which gradually diminish in size from the base to the summit of the areas,
and are separated by a zig-zag line of small granules occupying the line of the suture
(fig. 2 4); the poriferous zones are slightly waved, the pores are separated by thick septa,
the external surface of which form slight eminences, and there are five pairs of pores
opposite each large plate.

The inter-ambulacral areas are three times the width of the ambulacral, each plate sup-
ports two primary equal-sized tubercles (fig. 2 4), which have prominent bosses with well-
defined areolas, surrounded by incomplete circlets of small granules (fig. 2 6).

The long, round, slender spines referred to this species (fig. 2 c) have their
surface sculptured with fine longitudinal lines; the articulation is small, with a smooth
rim; the head is short and stout, with a thin, finely milled, prominent ring ; the stem is
much smaller in diameter than the head.

Afinities and differences.—The fragment (fig. 2 @) is all that I have seen of the test
of this species; it belongs to the section with several rows of tubercles in the inter-
ambulacra, but the specimen is too imperfect for comparison with other forms.

Locality and Stratigraphical position —tThis species was collected by Z. Hunt, Esq.,
from the Kimmeridge Clay, at Hartwell, Bucks, and was kindly communicated by Professor
Morris, to whose collection it belongs.

Humiprpina Cunninetoni, Wright. Pl. XII, fig. 3 a, 6.

HeMipepIna Cunninetoni. Wright, Annals and Magazine of Natural History, 2d series,
vol. xvi, p. 198.
= _ Woodward, Memoirs of the Geological Survey, Decade v,
** Notes on Echinopsis.”

Form unknown ; ambulacral areas with two marginal rows of very small tubercles ;
poriferous zones straight, pores obliquely disposed; inter-ambulacral areas with two rows
of tubercles on the zonal sides of the plates, miliary zone wide, filled with from eight to
ten rows of small granules; bosses large and prominent; areolas surrounded by complete
circles of granules.

Dimensions.—Transverse diameter, upwards of one inch ; height unknown.
Description.—The fragment figured 3 a, 4, is all that is known of this urchin, which

shows that it belongs to that group of the Hemipedinas having two rows of tubercles on
the poriferous side of the plates, and a wide miliary zone between them. It is much to be

168 HEMIPEDINA.

desired that a more diligent search should be made for Echinoderms, in Kimmeridge Clay
districts, as the little at present known of this class consists only of fragments of tests
and detached spines.

The ambulacral areas are narrow, with two marginal rows of small tubercles, rather
irregular in the mode of their arrangement (fig. 3 4); the poriferous zones are straight,
the pores are placed obliquely, and there are four pair of pores opposite each large plate.

The inter-ambulacral areas are three times the width of the ambulacral; they have
only one row of tubercles on the zonal sides of the plates (fig. 3 4), which leaves a
wide space between the areolas and the central suture; this is filled with four or five
rows of small granules, which, with those on the adjoming plate, form a miliary zone
with from eight to ten rows of granules; the bosses are large and prominent, and
the tubercles are of proportionate magnitude, the areolas are complete, and surrounded by
circles of granules of the same size as those which fill the zone.

Affinities and differences.—The fragment (fig. 3 a) formed part of a species belonging
to the first section of the genus, with two rows of tubercles, and a wide miliary zone in
the inter-ambulacra, but, like the preceeding species, it is too imperfect for comparison.

Locality and Stratigraphical position.— This fragment was collected from the
Kimmeridge Clay, near Aylesbury, by Z. Hunt, Esq. and was kindly communicated by
Professor Morris.

169

NOTES.

Or ForricN JURASSIC SPECIES OF THE GENUS HEMIPEDINA NEARLY ALLIED TO
BRITISH FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOoLITES.

HemrirEpIna sERIALE, Leymerie. Mém. de la Société Géologique de France, 1839,
tome ui, Pl. 24, fig. 1.
Wright. Monogr. Brit. Ool. Echinodermata. Pl. IX, fig. 3 a, 6.

Test hemispherical, subglobose above, flat below; ambulacral areas, with two rows of
tubercles, nearly as large as those of the inter-ambulacra ; inter-ambulacral areas, with six
rows of tubercles abreast at the equator, diminishing to four, and two rows above; a few
secondary tubercles are unequally distributed amongst them; mouth opening small ;
peristome slightly decagonal.

Formation.—Lower Lias, France.

Collection.—M. Michelin, Paris.

Hemipeepina Samanni, Wright. Nov. sp.

Test small, hemispherical; ambulacral areas with two rows of tubercles; inter-
ambulacral areas with one row of primary, and two rows of secondary tubercles, the
primary alternating with the secondary tubercles, but not disposed on the same line, as in
most other species; tubercles of both areas nearly the same size.

Formation.—Coral Rag, Commercey, Meuse.

Collection —My cabinet, kindly sent by M. Seemann, of Paris.

170 FOREIGN OOLITIC HEMIPEDINAS.

Hemirrpina NattHrimense, Quenstedt.

Ecuinopsis NATTHEIMENSIS. Quenstedt, Handbuch der Petrefactenkunde, pl. 49, fig. 37.

Test small, sub-pentagonal, depressed; ambulacra straight, one half the width of
row inter-ambulacra, with two rows of tubercles, nine to ten in each; a row of granules
extends along the tract of the suture, and transverse branches pass in lateral directions
from the main line; poriferous zones narrow, and strictly unigeminal ; inter-ambulacra
twice as wide as the ambulacra, with two rows of primary tubercles, nine im each
row, placed near the centre of the plates; the bosses surrounded by distinct areolas,
complete circles of small granules encircle them; near the base, some of the
granules attain the size of secondary tubercles, with perforated summits; the tubercles of
both areas small and nearly of the same size, those of the inter-ambulacra a little larger
than those of the ambulacra; apical disc small; the ocular plates extend beyond the
line of the genitals, and are perforated near their centre ; vent round, surface of the disc
covered with small granulations ; mouth opening large and decagonal, lobes unequal.

Dimensions.—Transverse diameter, eleven twentieths of an inch.

Formation.—W hite Jura, « Nattheim.

Collections.—Professor Quenstedt, Tiibingen.
British Museum.

Hemipepina Boucnarotl, Wright, nov. sp. Mr. Davidson’s MS., Plate IIT bis., figs. 1, 2, 3.

Test large, depressed ; ambulacral areas with two rows of regular marginal tubercles,
extending without interruption from the peristome to the apical disc; and separated by
a median row of granules, with transverse branches ; poriferous zones narrow, straight,
and strictly unigeminal; inter-ambulacral areas three times the width of the ambulacral,
with ten rows of tubercles at the equator, each inter-ambulacral plate in this region having
five tubercles arranged on the same line; areolas narrow, and surrounded by circles of
granules ; tubercles of both areas small and nearly of the same size; spines long, slender ;
stem covered with well-marked longitudinal lines.

Dimensions.—Transverse diameter, two inches and one quarter; height unknown, a
the specimen is crushed.

Formation —Kimmeridge Clay, collected by M. Bouchard Chantereaux, from a cliff
near Boulogne-sur-Mer. Very rare.

Collection.—M. Bouchard-Chantereaux, at Boulogne-sur-Mer.

FROM THE INFERIOR OOLITE. 171

Genus—PEDINA, Agassiz, 1840.

The urchins grouped in this genus are sometimes large, but in general they are of
moderate size; their test is much inflated at the sides, and nearly equally depressed on
the upper and under surfaces. The shell is extremely thin, and the plates have numerous
small tubercles developed on their surface.

The ambulacral areas are narrow, from one third to one fourth the width of the inter-

ambulacral; they have two rows of marginal tubercles, often as large as those of the other
areas.
The inter-ambulacral areas are wide, with two rows of primary, and two or four rows
of secondary tubercles, which extend only from the peristome to the circumference. The
tubercles are perforated, the bosses have smooth uncrenulated summits, and the areolas
are narrow and superficial.

The poriferous zones are wider than in the other Diapremapgz, and the pores are
arranged in oblique ranks, with three pairs in each file. In this respect the Pedinas
resemble the Ecury1pa, and form a connecting link between these two natural families.

The mouth opening is small, in general from one third to one fourth the diameter of
the test; the peristome is divided by narrow superficial notches into ten nearly equal-
sized lobes.

The apical disc is small; the genital plates are nearly equal, but the right antero-
lateral, with the madreporiform body, is a little larger than the others; the ocular plates
are small, and both genitals and oculars are perforated near their outer third.

The spines, unfortunately, are unknown.

The Pedinas were first described by Professor Agassiz as having perforated tubercles,
with crenulated bosses. ‘‘ Enfin un dernier caractére de ce genre consiste dans la petitesse
de ses tubercles, lesquels cependant sont perforés et mamelonnés comme ceux des
Diadémes.”*

In their ‘ Catalogue raisonné des Kchinides,’+ MM. Agassiz and Desor defined this
genus—‘Oursins comprimés, a test mince, & bouche petite, peu entaillée. Trois paires
de pores obliques. Tubercles perfores et crénulés comme chez les Diademes. ‘Toutes les
especes sont fossiles; des terrains Oolitiques et Crétacés.”

The same definition was adopted by M. Cotteau;{ and as the specimen I first de-
scribed was not well preserved, I repeated§ the statement on the authority of these

writers.
The discovery, however, of a number of good specimens of Pedina rotata enabled me

*¢ Echinodermes Fossiles de la Suisse,’ 2de partie, p. 33.

+ ‘Annales des Sciences Naturelles,’ 3me serie, tome vi (1846), p. 370.
TN Etudes des Echinides Fossiles,’ p. 191.

§ «Annals and Magazine of Natural History,’ 2d series, vol. viii, p. 272.

23

172 PEDINA.

to prove that the bosses are smooth, and without any trace of crenulation, in this genus ;*
the accuracy of this observation has been confirmed by M. Cotteau,t who has added
the following note to his description of Pedina aspera: “M. Wright est le premier qui a
constaté contrairement a l’opinion de M. Agassiz, que les tubercles des Pédines sont cer-
tainement depourvus de crénelures. Sur tous les échantillons de Pédine, que nous avons
examinés depuis, nous avons été a méme de reconnaitre l’exactitude de cette observation.”

When I first pointed out the true structure of the bosses in the Pedinas to my late
colleague, Professor Hdward Forbes, he considered the fact of so much importance, that he
proposed to suppress the genus Pedina, and merge its species into Hchinopsis, as one of
the characters given of Mchinopsis was that “the tubercles were perforated but not
crenulated.” For this reason, in the class Echinodermata in Morris’s ‘ Catalogue of British
Fossils,’ from the pen of Professor Forbes, and likewise in lettermg Plate 3, Decade V, of
the ‘Memoirs of the Geological Survey,’ this view was carried out.

The genus Pedina was well described and figured by Agassiz in his ‘ Echinodermes
Fossiles de la Suisse,’ and its limits accurately indicated, before Hchinopsis was proposed.
Assuming, therefore, that the diagnosis of both genera was equally well defined, which is
not the case, still Pedina has the priority.

In the absence of good type specimens, it is impossible to make a correct comparison
between Fehinopsis and Pedina from the definitions in the books; and if M. Desor, who
has lately carefully examined the types of Hchinopsis, declares the genus to be unsatis-
factory, this is another reason why we should retain Pedina. In his note on
this genus, M. Desor} says: “Mais meme tel qu'il est ici défini, le genre Hchinopsis est
encore moins précis qu’on ne pourrait le désirer, car il renferme des espéces 4 pores
simples et d’autres a pores dédoublés. Mais comme ces deux types sont si voisins sous
tous les autres rapports, particuliérement par leur forme renflée, la petitesse de leur péri-
stome et la structure de leur plaques, je n’ai pas cru devoir les séparer génériquement.
Je me suis borné a en faire deux groupes.”

The genera Pedina and Hchinopsis are the only ones in which we find perforated
tubercles combined with trigeminal pores; but in Achznopsis the ambulacral areas are
nearly as wide as the inter-ambulacral, which is not the case in Pedina.

The Pedinas have perforated tubercles, with smooth bosses, combined with trigeminal
pores, by which they are distinguished from Pseudodiadema. They closely resemble
Hemipedina, from which they are chiefly distinguished by the smallness of their tubercles,
and the trigeminal arrangement of their pores, those in emépedina bemg unigeminal ;
the apical disc is likewise much larger in Hemipedina.

The perforation of the tubercles distinguishes Pedina from the true Ecutnipa, which it
otherwise resembles in having a thin test, with trigeminal pores.

* «Annals and Magazine of Natural History,’ 2d series, vol. xii, p. 173.
+ © fitudes sur les fichinides Fossiles,’ pp. 313, 314.
t ‘Synopsis Echinides Fossiles,’ p. 99.

FROM THE INFERIOR OOLITE. 173

The Pedinas are all extinct, and appear to be limited to the Oolitic rocks. One
species is catalogued with doubt as coming from the Cretaceous formation.

Prpina rorata, Wright (non Agassiz). Pl. XIII, fig. 1 a, 4, ¢, d, e.

Ecuinus tinnatus. Murchison, Geology of Cheltenham, 2d edit., p. 73 (1845).

PEDINA ROTATA. M‘Coy, Annals and Magazine of Natural History, 2d series, vol. ii,
p. 20 (1848).

_ — Wright, Annals and Magazine of Natural History, 2d series, vol. viii,

p. 273 (1851).

Ecutnopsis rotata. Forbes, in Morris’s Catalogue of British Fossils, 2d edit., p. 78 (1854).

= == Salter, Memoirs of the Geological Survey, Decade V, pl. 3 (1856).
PEDINA ROTATA. Cotteau, Etudes sur les Echinides Fossiles, p. 315 (1856).

Test circular, or sub-pentagonal, with tumid sides, more or less depressed ; ambulacral
areas narrow, furnished with two marginal rows of small, numerous (from twenty-five to
thirty in each row,) close-set, equal-sized tubercles, arranged with great regularity through-
out; and two inner rows of minute tubercles, which disappear above and below ; inter-
ambulacral areas wide, with two rows of primary, which extend without interruption from
the mouth to the disc, and four rows of secondary tubercles on their outer side, which
disappear at the equator; mouth opening small, peristome decagonal, with deep notches
and unequal-sized lobes, apical disc of moderate size, genital plates nearly equal, poriferous
zones wide, trigeminal ranks oblique, with two granules between each rank.

Dimensions.—Height, seven tenths of an inch; transverse diameter, one inch and four
tenths.

Description—There is much difficulty in distinguishing by good characters the different
species of Pedina figured by M. Agassiz in his ‘ Hchinodermes Fossiles de la Suisse,’
arising in a great measure from the thinness of the test, the delicacy of its sculpture,
and the great similarity which prevails among the different species of this group; the
absence of good details of structure in the plates, showing the specific characters of each
form, and of an accurate diagnosis in their description, tends to increase the difficulty ;
any attempt, therefore, to clear up the synonymy of these species is hopeless, without an
attentive examination of the types themselves ; fortunately, this has been done by a most
competent and learned observer, M. Cotteau, whose analysis of the species will be given
when treating of the affinities of the urchin now under consideration.

In my Memoir on the Cidaridz of the Oolites, I erroneously identified this species
with Pedina rotata, Agass., which is now considered hy MM. Agassiz and Desor to be a

174 PEDINA.

variety of Pedina sublevis ; that name having thus become obsolete, so far as it relates to
the Swiss urchin, and our species having been beautifully figured, in the ‘ Memoirs of the
Geological Survey, under the specific name I first gave it, I have retained it in this
work.

The test of this urchin is in general circular, but in some specimens it nas a sub-pen-
tagonal form (fig. 1 4). Its sides are always more or less tumid, and it is nearly equally
depressed on the upper and under surfaces (fig. 1 e).

The narrow ambulacral areas are furnished with two rows of small, numerous, equal-
sized tubercles, from twenty-five to thirty in each row, which are closely set together
on the margins of the area, and arranged with great regularity throughout; in the
middle third there are two rows of minute tubercles within the marginal rows, which
disappear above and below; a double line of small granules descends in a zigzag form
between the tubercles, and sends small lateral branches, to encircle the marginal rows
(fig. 1 a, 4, e).

The inter-ambulacral areas are four times as wide as the ambulacral (fig. 1 c); in the
specimen figured there are fifteen plates in each column; each plate supports one
primary tubercle, situated near the zonal border of the plate (fig. 1 e), and between
the peristome and the circumference, two secondary tubercles, on the sutural side of the
primaries (fig. 1 e); on the upper surface the secondary tubercles gradually disappear, so
that the under surface of the test (fig. 1 a) is much more tuberculous than its upper
surface (fig. 1 6); the areolas are very narrow, but not at all excavated, and around them
circles of small granules are regularly disposed; the primary tubercles form ten con-
spicuous rows, which are nearly equidistant from each other, whilst the secondary tubercles
are not so regular in their arrangement.

The poriferous zones are wide, in which the holes are closely arranged in triple oblique
pairs ; the obliquity, however, is greater on the upper than on the under surface, where
the holes are so disposed, that the undermost pair of each trigeminal rank forms an oblique
line with the uppermost pair of the rank immediately below it, leaving the middle pair

by themselves, thus— “2, .. Hach pair is surrounded by a slight oval rim, which is

only seen, however, on the best-preserved specimens ; there are three oblique pairs of holes
opposite each large plate (fig. 1 c) ; and between each trigeminal rank there are two small
tubercles (fig. 1 6).

The base is flat, the mouth opening small, being about two sevenths the diameter
of the test ; the peristome is decagonal (fig. 1 a), and divided by deep notches into ten
nearly equal-sized lobes, those corresponding to the ambulacra are the largest.

The apical disc is moderately large, being two sevenths the diameter of the test
(fig. 1 4); it is often well preserved, as in fig. 1 6; the genital plates are nearly all of
the same size (fig. 1 d); the right antero-lateral, supporting the fine spongy madreporiform
body, is a little larger than the others (fig. 1 d); they have alla heptagonal shape, and

FROM THE INFERIOR OOLITE. 175

their apices form angles re-entering into the inter-ambulacral areas (fig. 1 4); the ocular
plates are small pentagonal pieces, firmly wedged between the genitals; the eye-holes
are very minute, and the surface of the discal elements is covered with numerous small
granules ; the oviductal and eye-holes are perforated about the junction of the outer with
the middle third of the plates. The anal aperture is central and circular (fig. 1 d), and
in diameter is about the length of one of the genital plates.

Affinities and differences— This species very much resembles Pedina Gervillit,
Desmoulins, in fact, it requires a close and critical comparison of good specimens to discover
the differences between them ; Pedina rofata has more tumid sides, the ambulacral areas
possess a greater number of small, equal-sized tubercles, more closely set together, and
arranged with greater regularity than in Pedina Gervillii ; the poriferous zones are like-
wise wider, and the pores lie more oblique, with two granules between each rank; the
primary tubercles are larger and more promiment; and there is, consequently, a greater
disproportion between the tubercles of the ambulacral and those of the inter-ambulacral
areas than in Pedina Gervillit.

It differs from Pedina sublevis in having larger tubercles in the inter-ambulacra, and
in the number, approximation, and regularity of the arrangement of the ambulacral
tubercles.

M. Cotteau* has examined the types of M. Agassiz’ species contained in the magni-
ficent collection of M. Michelin, and has given the following analysis of the affinities and
differences which exist between the four species he describes, and which I have translated
for this section.

“Ist. The Pedina sublevis, Agassiz, which is characterised by its great height, its pores
disposed by very oblique triple pairs, its primary tubercles slightly developed, spaced out,
and confounded, so to speak, especially at the base, with the secondary tubercles which
accompany them. We consider the Pedinu ornata, Ag., as a variety of this species.

“2d. The Pedina Gervillii, Desmoulins ; remarkable by its depressed form, its principal
ambulacral and inter-ambulacral tubercles few in number and spaced out, its secondary
tubercles very small, its pores largely open, ranged in triple oblique pairs, with little
obliquity, and, consequently, enclosed in narrow poriferous zones.

“3d. The Pedina rotata, Wright; assuredly very near to Pedina Gervillit, but distin-
cuished from it by its more tumid form, its pores disposed more obliquely, its ambulacral
tubercles smaller, closer set together, more numerous, and forming on the borders of the
poriferous zones perfectly regular ranges, ‘This last character suffices to distinguish Pedina
rotata from young individuals of Pedina sublevis. We retain to this species the name
rotata, with this observation, that in the figures of the ‘Bchinodermes de la Suisse’
(pl. xv, figs. 46), the mouth is relatively smaller, and the ambulacra] tubercles are more

spaced out.

* «Btudes sur les Echinides Fossiles,’ p. 315.

176 PEDINA.

“Ath. The Pedina aspera, Agassiz,which is distinguished from the preceding species by
its more granular aspect, by its principal tubercles being larger and more prominent, by its
more numerous secondary tubercles, and by its poriferous zones being still more narrow
than those of Pedina Gervillii.”

M. Cotteau adds, that stratigraphical geology completely justifies these distinctions ;
Pedina rotata comes from the Inferior Oolite of England, Pedina Gervillit is met with
in the Callovien stage of the Sarthe, Pedina sublevis characterises the inferior layers of
the Coral Rag, and Pedina aspera appears to be special to the Kimmeridge Clay.

Locality and Stratigraphical position.—This species was first found in the upper
ragstones of the Inferior Oolite, in a thin marly vein, which, in some places, rests on
the Trigonia grit, in the same bed with Ammonites Parkinsont, Sow. I have collected
it from this stratum at Shurdington, Cold Comfort, and Hampen, in Gloucestershire ;
in the latter locality it is associated with Molectypus depressus, Leske, Holectypus
hemisphericus, Desor, Echinobrissus Hugi, Agass., Echinobrissus clumcularis, Lihwyd,
Clypeus sinuatus, Leske, and Stomechinus intermedius, Agass. ‘The Rev. A. W. Griesbach
has discovered two fine large specimens in the Cornbrash of Rushden, Northamptonshire.
Professor M‘Coy gives the Great Oolite of Minchinhampton as the locality for the
specimen in the Cambridge Museum. ‘The specimen, figured in the ‘Memoirs of the
Geological Survey’ was found in the upper beds of the Inferior Oolite, at Hampen,
in the same bed from whence the specimens figured in Pl. XIII were obtained.

Prpina Smita, Forbes. Pl. XIII, fig. 2 a, 6, c.

Crpazris, sp. 2 of William Smith’s Stratigraphical System of Organized Fossils, p. 109.
Ecuinopsis SMitHi1. Forbes, Memoirs of the Geological Survey, Decade V, pl. 3.
Notes on British Echinopsis.
— — Morris, Catalogue of British Fossils, 2d edit., p. 78.

Test pentagonal, much depressed; ambulacral areas narrow, and extremely prominent,
with two rows of tubercles, which closely alternate in the lower half of the area, but
abruptly cease on the upper half; imter-ambulacral areas wide, with two rows of primary
tubercles, which occupy the zonal sides of the plate, and form a continuous series
from the mouth to the disc, and two short secondary rows, which extend from the
peristome to the circumference, where they abruptly cease; the miliary zone is wide,
and covered with numerous granules, among these several small perforated tubercles occur ;
mouth opening large, peristome with deep incisions, and unequal-sized lobes.

Dimensions. —Height, about one inch; transverse diameter, nearly two inches.

FROM THE INFERIOR OOLITE. 177

Description —I only know two fragments of this remarkable Pedina, the one (fig. 2 a)
was collected by the late Dr. William Smith from the Inferior Oolite at Tucking
Mill, the other (fig. 2c) I found in the Inferior Oolite, near Birdlip. The description
given by Dr. William Smith of this species was the following :

“‘Pentangular, depressed, with projecting and rather distant small mamille; two
contiguous 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 triporous.

“The areola form the angles of the pentagon. The two larger 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.”

Dr. Smith’s specimen is a fragment (fig. 2 a) which exhibits a part of two inter-
ambulacral and an ambulacral area, the upper surface is concealed, and only two of
the notches of the peristome are exposed; the other specimen (fig. 2c) is smaller,
but shows more of the form and structure of the test. The ambulacral areas are narrow
and straight ; their two rows of tubercles, which are nearly as large as those of the
inter-ambulacra, closely alternate (fig. 2 4) between the peristome and the circumference,
but as suddenly disappear from the upper part of the area (fig. 2 c).

The poriferous zones are wide, extremely so below (fig. 2 a), where the trigeminal
ranks lie at angles of from 15° to 45° (fig. 2 4), above the ranks are more oblique, and
wider apart, but throughout, the pores are always arranged in triple oblique pairs.

The inter-ambulacral areas are upwards of three times the width of the ambulacral ;
from the peristome to the equator each of the inter-ambulacral plates has two tubercles
developed on its surface (fig. 2 4), the primaries occupy the zonal sides of the plates, and
the secondaries their outer margin; the primary tubercles, nine or ten in each row,
are raised on very prominent bosses (fig. 2 4), encircled by smooth well-defined areolas,
around which circles of small granules are disposed (fig. 2 4); as the tubercles are placed
very near the ambulacra, and the secondaries are absent on the upper surface, there is
an unusually wide miliary zone in this region of the test, which is filled with numerous
small granules, among which some minute perforated tubercles are interspersed (fig. 2 0).

The upper surface of the specimen (fig. 2) is covered with an extremely hard
rock, that of fig. 2¢ shows the opening for the apical disc, which is of moderate
width. Only two of the notches of one angle of the mouth (fig. 2 a) are exposed; they
are deep, and have reflected edges; the peristome is unequally lobed, and those of the
ambulacra are much the largest.

Affinities and differences.—The only urchin which this species resembles is Hemipedina
Bakeri, Pl. X, fig. 1; the mode in which the tubercles closely alternate in the ambulacra,
and the proximity of the primary tubercles to the poriferous zones, show the near

178 PEDINA.

affinity which exists between them; it is not improbable that a series of specimens might
prove H. Baker: to be the young condition of Pedina Smithii, although, in the present
state of our knowledge of these forms, I should not be justified in stating such
to be the fact.

Locality and Stratigraphical position.—The large fragment (fig. 2 a) was collected
by the late Dr. William Smith, at Tucking Mill, im Moreton Combe, south-east of Bath,
from a rock which I take to be Inferior Oolite. The specimen (fig. 2c) I collected
from the Inferior Oolite at Birdlip, near Cheltenham; it is the only specimen of the
species I have found.

LNstory.—As this is one of the Echinodermata belonging to Dr. Smith’s original
geological collection, deposited in the British Museum, its history is more than usually
interesting. My friend, Mr. Woodward, first called Professor Forbes’s attention to the
specimen, who named it in honour of the father of English geology. In the description
of the species, however (Notes on British Hehenopsis, in the ‘ Memoirs of the Geological
Survey,’ Decade V), it is erroneously stated to have been collected from the Coral Rag,
instead of from the Inferior Oolite. This remarkable form is now figured for the
first time.

179

NOTES

On Foreign JURASSIC SPECIES OF THE GENUS PEDINA NnrarRLy aLuizp to Britisa
FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITES.

PEDINA ARENATA, Agassiz. Echinoderm. Foss. Suisse, II, tab. xv, figs. 1—3.

Test small, hemispherical, flat at the base, convex on the upper surface ; ambulacra
with two rows of marginal tubercles, placed apart and separated by fine granules;
poriferous zones very narrow, trigeminal ranks nearly upright ; inter-ambulacra with two
rows of small primary tubercles, secondary tubercles very small and _ scarcely
apparent, except on the under surface; miliary granulation more abundant and
distinct than in the other species; centro-sutural line naked and _ conspicuous ;
mouth opening proportionately large, two fifths the diameter of the test, peristome
decagonal, and only slightly notched ; the size of the mouth opening distinguishes it from
other Pedinas.

Dimensions.—Height, six tenths of an inch; transverse diameter, one inch.

Formation.—Collected from the Inferior Oolite (Bajocien) of Goldenthal (J ura
Soleurois).

Collection.—M. Gressly, very rare.

Pepina Gurvituit, Desmoulins. 'Tableaux synonymiques des Echinides, p. 316, No. 19.

Test sub-pentagonal, depressed; ambulacra with two marginal rows of granules,
placed wide apart, a larger and smaller tubercle alternating on the same row ; in the structure
of the ambulacra the difference between this species and Pedina rotata is chiefly observed ;
inter-ambulacra with two rows of primary and four rows of small secondary tubercles ;
poriferous zones narrow, pores largely open, trigeminal ranks slightly oblique, mouth
opening small, peristome decagonal and deeply notched; apical disc moderate in size,
genital plates nearly equal.

Dimensions.—Height, thirteen twentieths of an inch; transverse diameter, one inch
and one quarter.

24

180 FOREIGN JURASSIC PEDINAS.
Formation.— Abundant in the “ Callovien étage de Chauffour (Sarthe).”” Tricur.

Collections—MM. Michelin, Desmoulins, Cotteau, de Loriére, Triger. My cabinet.

PEDINA SUBLEVIS, Agassiz. Vchinoderm. Foss. Suisse, I, tab. xv, figs. 8—13.

= — Cotteau. Etudes sur les Echinides Fossiles, pl. 26, figs. 1—6.
== — SBronn. Lethza Geognostica, dritte Auflage, tab. xvu, fig. 10.

Test circular, shell extremely thin, equally depressed at both surfaces ; ambulacra with
two rows of small tubercles, spaced widely apart, and accompanied by secondary tubercles ;
inter-ambulacra three times as wide as the ambulacra, with two rows of primary, and four
rows of secondary tubercles nearly as large as the primaries; tubercles of both areas
nearly of the same size, and placed wide apart; poriferous zones rather wide, trigeminal
ranks very oblique below, nearly vertical above ; mouth opening small, peristome decagonal,
and deeply notched.

Dimensions.—Height, seven tenths of an inch; transverse diameter, two inches.

Formation.—Corallien (Terr. a Chailles) des Ravieres prés de Locle, Val-de-Travers
(Jura Neuchatelois). Desor.—Dans les couches calcareo-siliceuses de
Chatel-Censoir et de Druyes. Cotteauw. ‘This species is the most
abundant of the genus, and is widely distributed through the
Corallian stage of France, Germany, and Switzerland.

Collections. —MM. Michelin, Cotteau, and in most Continental museums. British
Museum.

Prpina Mtcueutnt, Cotteau. Etudes sur les Echinides Foss., pl. 23, figs. 2—A4.

Mould much inflated, and sub-pentagonal, slightly depressed at both poles; inter-
ambulacra very wide, with a median depression ; ambulacra very narrow ; poriferous zones
very narrow, trigeminal ranks nearly straight; test unknown. ‘This species is found
always as a siliceous mould.

Dinensions.—Height, one inch and seven twentieths ; transverse diameter, two inches.

Formation.—‘ Dans les couches calcareo-siliceuses de Pétage Corallien imférieur, a
Chatel-Censoir et a Druyes.” Cotteau.

Collections.—Abundant. My cabinet.

FOREIGN JURASSIC PEDINAS. 181

Pepina Cuarmassel, Cotteaw. Etudes sur lex Echinides Foss., pl. 24, figs. 1—3; pl. 25,
figs. 1—8.

Test large, extremely thin, sub-circular; hemispherical and inflated on the upper
surface, flattened on the under surface; ambulacra with two rows of tubercles, as large as
those in the inter-ambulacra, set closely and regularly together, on the extreme margins of
the area; the intermediate miliary zone covered with fine granulations, poriferous zones
wide, trigeminal ranks very oblique ; inter-ambulacra four to five times the width of the
ambulacra, with four rows of primary tubercles, which extend very regularly from the
mouth to the summit; tubercles small, slightly developed, well spaced out, and
accompanied with secondary tubercles almost as large, and which form, at the inferior
surface, and towards the circumference of the test, some irregular rows, extending to
the upper surface; mouth opening small, peristome divided by wide notches into ten
unequal lobes. 2
Dimensions.—Height, two and a half inches; transverse diameter, four inches and a

quarter.

Formation.— Dans les couches calcareo-siliceuses subordonnées au Coral-rag inférieur,
avec Pedina Michelini et sublevis presque toujours a l'état de moule
intérieur siliceux.” Cotteau.

Collection.—M. Cotteau, very rare; plaster mould in my cabinet.

Pepina aspera, Cotteau. Etudes sur les Echinides Foss. pl. 44, figs. 7—12.

Test circular, thin, nearly equally depressed at both poles ; ambulacra with two rows of
marginal, well-spaced-out tubercles ; inter-ambulacra thrice as wide as the ambulacra, with
two rows of primary tubercles, larger and more developed than in other Pedinas, and
surrounded by areolas ; several secondary tubercles scattered over the surface of the plates ;
poriferous zones narrow, trigeminal ranks not very oblique; mouth opening small,
peristome not deeply notched.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, one inch and
one tenth.

182 FOREIGN JURASSIC PEDINAS.

Formation.—‘“ Le Pedina aspera caractérise les couches inférieures du Kimmeridge ;
nous l’avons rencontré dans les marnes de Baroville et des Riceys
(Aube), owilest assez rare. M. Royer nous en a communiqué deux
échantillons fort beaux recueillis par lui dans le Kimmeridge
inférieur de Marbeville (Haute Marne).” Cotteau.

Collections. —MM. Cotteau, Royer.

ECHINID/. 183

Family 4—ECHINID At.

This extensive natural family comprehends many genera of living and fossil urchins :
some of which are large and globular; others are of moderate size, or small, hemispherical,
or depressed: in general the test is thin, and each column is composed of a considerable
number of plates.

The ambulacral areas are about one third the width of the inter-ambulacral; they have
two, four, or more rows of tubercles developed on their surface, which are often nearly
as large as those of the inter-ambulacral areas.

The poriferous zones present considerable diversity in the number and arrangement
of the pores: in one section they are in single pairs; in a second they form double rows ;
in a third they are in triple oblique pairs; and in a fourth the wide poriferous zones have
the pores disposed in three vertical rows.

The inter-ambulacral areas are more or less wide, and their large pentagonal plates
are four times as long as they are broad; they are sometimes perforated at the
angles, as in Mespilia and Microcyphus; or they have depressions in the line of the
sutures, as in Zemnechinus and Opechinus; the surface is sometimes sculptured with
irregular figures in relief, as in Glypticus, or finely and microscopically plaited as in
Codiopsis ; for the most part the plates have numerous tubercles developed on their surface.

The tubercles are in general small, and nearly of the same size in the ambulacral and
inter-ambulacral areas; their bosses have smooth summits, and they are always
imperforate ; there are often several rows on the same horizontal line.

The spines are always short and subulate, and their surface is sculptured with fine
longitudinal lines.

The mouth opening is sometimes small, and sometimes very large; the peristome is
often pentagonal, and feebly indented ; or it is deeply incised, and divided by notches into
unequal-sized lobes.

The apical disc is small, and composed of five genital and five ocular plates;
the spongy madreporiform body is always prominent on the right antero-lateral genital
plate. .

The large and powerful jaws are composed of the same pieces as in the Cidaride ;
but the pyramids are excavated in their upper part, and the two branches are united by an
arc at the summit: the teeth are long and tricarinated.

In the following table I have endeavoured to classify the genera, and to show
at one view the most striking characters of the different groups included in this
family :

184 ECHINID &.

A TABLE SHOWING THE CLASSIFICATION OF THE ECHINIDA.

FaMILy. SECTIONS. DiaGnosis. GENERA.
¢ Inter-ambulacra with irregular sculptured plates on the upper
surface of the test. } CREPMOUS, ICO,
Upper surface of both areas finely plaited; large tubercles at } Copropsts, Agassiz.
the base only; mouth small.
( 3 Plates of both areas with pyriform depressions in a portion i Teainneniius CRE
I 8 of the line of the sutures; ambulacra wide. i 5
ne Plates with deep depressions along the whole line of the ; AERIS
* Zo sutures; ambulacra narrow; mouth small. i ;
6 é 2 Numerous small, equal-sized tubercles in both areas ; two rows !
3 Ra in the ambulacra, and four to ten in the inter-ambulacra. } Hontnociparts, Desmoulins.
2 z ® Surface granular, with numerous small, close-set tubercles ;
a cS mouth small; peristome feebly indented. } Corranpia, Desor.
3S Inter-ambulacra lobed, wa numerous small, close-set tuber- | MAGNGHTACUAT OE
\_ cles; mouth large; peristome pentagonal. *
rf $ 3 fie areas naked in the middle, tubercles on the sides, with wet a
- 8 2 8 a | sutural pores, and a tuberculous base. } ee
g 3 = B Tubercles numerous, equal-sized, sporadic; inter-ambulacra
: ° & Ss am with naked horizontal spaces in the line of the sutures; ; MicrocyPuts, Agassiz.
5 a iS é angular pores.
Zz
= : ;-Tubercles small, limited to the sides of the areas ; test globu- oped. atecoh
a) sa lar, with a very small pentagonal mouth. i pete
3 eA Tubercles small, numerous, equal-sized, in vertical and hori- pada P, 59
o) EA & zontal rows ; larger at the base; mouth large, pentagonal. } ES US
z ae Tubercles numerous, in many unequal, vertical rows; mouth ie
e 2 moderate ; peristome feebly notched. | SAMMECHINUS, Agassiz.
4A = ‘5 Tubercles numerous, same size in both areas; mouth small;
= 4 peristome with deep, narrow slits. } Ecurnus, Linneus.
AS Tubercles unequal, two or more rows in each area, with seconda-
am l ries ; mouth very large, pentagonal, with wide, deep notches. } SPQuEeHINUS WOE
oA oi Tubercles small, irregular, sporadic ; middle of the ambulacra
a a 3 6 a naked; pores at the angles of the plates. } AMBLYPNEUSTES, Agassiz.
z 2 a a Tubercles small, numerous; the inner row of pores se-
5 Bmas parated from the two outer rows by a line of tubercles. Bouxtta, Desor.
wa 7 > 2 | Tubercles not prominent ; the outer and inner rows of pores
L Au é rectilinear and regular, the middle row irregular. } TRIPNEUSTES, Agassi.

GLYPTICUS. 185

Genus—GLYPTICUS, Agassiz. 1840.

The urchins grouped in this small genus constitute a type which is easily recognised,
although in an organic point of view their most striking external character is not of the
first value; in fact, the irregular structure of the tubercles of the inter-ambulacral areas
essentially determines the peculiar physiognomy of the genus.

The small urchins composing this genus have a thick test, and a round, depressed, or
sub-conoidal form; the ambulacral areas are narrow and straight, with two rows of
marginal tubercles, very regularly arranged throughout.

The poriferous zones are narrow, and the pores strictly unigeminal.

The inter-ambulacral areas have two rows of well-developed tubercles at their base ;
but on the upper part of the area the regular tubercles disappear, and the surface of the
plates is deeply sculptured with remarkable figures, which, in some species, resemble
hieroglyphical characters.

The apical disc is large; the genital plates are prominent, and have their surface sculp-
tured; the eye-plates are large, and the lines of division between the plates are very
strongly marked.

The mouth opening is wide; the peristome decagonal, the notches are shallow, and
the lobes very unequal.

The tubercles of both areas are imperforate, and have smooth, uncrenulated bosses.

Glypticus resembles Temnopleurus in having the plates sculptured on the upper surface ;
but in the former the figures are in relief, whilst in the latter the sculpture consists of deep
impressions corresponding to a portion of the sutures of the ambulacral and inter-ambulacral
areas. In Zemnopleurus the tubercles form regular rows, and are crenulated, but imper-
forate ; the poriferous zones are undulated, and the pores are in threes. Glypticus was
thought to resemble Cyphosoma, but I cannot detect any two characters im common in
these genera. In Cyphosoma the tubercles are regular, and well developed through-
out; they have distinct areolas, crenulated bosses, and imperforate summits ; the poriferous
zones are undulated, and the pores bigeminal in the upper part of the zones.

Glypticus is distinguished from Pseudodiadema in the irregular sculpture on the inter-
ambulacra, and in having the tubercles imperforate and uncrenulated. It resembles one
section of that genus, however, in having the pores unigeminal in the zones.

Glypticus resembles Stomechinus in having the tubercles imperforate, and with smooth
bosses; but is easily distinguished by the sculpture on the plates, and the size and
foliated character of the apical disc.

The species of this genus have been hitherto found only in the Oxford Clay, Coral Rag,
and Portland beds, so that it belongs to the Middle and Upper divisions of the Oolitic

group.

186

GLYPTICUS.

Guypricus HIzROGLYPHICUS, Goldfuss. Plate XIII, fig. 3 a, 6, c¢, d,e,f.

GLYPTICUS HIEROGLYPHICUS.

ECHINITES TOREUMATICUS.

ECHINUS HIEROGLYPHICUS.
ARBACIA HIEROGLYPHICA.

EcHINUS HIEROGLYPHICUS.

GLYPTICUS HIEROGLYPHICUS.

Bourguet, Traité des Pétrifications, pl. 51. fig. 377 (1742).

Knorr, Recueil des Monuments des Catastrophes, que le globe
terrestre a essayées, contenant des Petrifications, tabl. 5 ii,
No. 35, fig. 3, 1775.

Leske, Additamenta ad Kleinii dispositionem Echinoderma-
tum, p. 156, pl. 44, fig. 2, 1778.

Goldfuss, Petrefacta Germanie, p. 126, tabl. 40, fig. 17, 1829.

Agassiz, Prodrome dune Monographie des Echinodermes,
p. 23, 1836.

Desmoulins, Tableaux synonymiques des Echinides, No. 60,
p. 292, 1837.

Lamarck, Animaux sans vertébres, 2“ edit., tome ili, p. 372,
No. 43, 1840.

Agassiz, Catalogus systematicus ectyporum Echinodermatum
fossilium, p. 13, 1840.

Agassiz, Echinodermes Fossiles de la Suisse, 2° partie, p. 96,
pl. 23, figs. 37—39, 1840.

Bronn, Index Palzontologicus, p. 186, 1849.

Agassiz and Desor, Catalogue raisonné des Echinides. Annales
des Sciences Nat., 3° série, tome vi, p. 360, 1846.

Bronn, Lethza Geognostica, 3‘* Auflage, Band ii, p. 146,
pl. 17, fig. 4, 1851.

D’Orbigny, Prodrome de Paléontologie stratigraphique uni-
verselle, tome ii, p. 26, 14th étage, No. 420, 1850.

Quenstedt, Handbuch der Petrefactenkunde, p. 581, 1852.

Cotteau, Etudes sur les Echinides Fossiles, p. 166, pl. 20, figs.
12—15, 1852.

Desor, Synopsis des Echinides Fossiles, p. 95, tabl. 16,
figs. 1—3.

Test thick, circular, flattened at the base, hemispherical on the upper surface, sub-
depressed; ambulacral areas narrow, straight, with two rows of marginal tubercles;
poriferous zones deeply sunk, pores unigeminal; inter-ambulacral areas wide, with two
rows of tubercles at the base; on the upper surface the plates are deeply sculptured with
irregular, hieroglyphic-like figures; tubercles imperforate and bosses smooth ; apical disc
large; genital plates elongated, with a sculptured surface, holes near the outer fourth ;
ocular plates triangular, holes marginal; mouth opening large, peristome decagonal,

Jobes unequal, notches small.

Dimensions.—Height, eleven twentieths of an inch; transverse diameter, one inch and

one tenth.

FROM THE CORAL RAG. 187

Description —This urchin has been long known to naturalists, having been figured by
Bourguet and Knorr in their respective works, cited in the synonymy. Leske, however,
in his ‘ Addimenta ad Kleinii Echinodermatum,’ first described this curious form under
the name Lehinus toreumaticus, and gave a figure of it in his pl. xliv, fig. 2. Some
authors have confused this species with Klein’s Cidaris toreumatica, which is quite a
different urchin, and forms the type of Agassiz’s genus Zemnopleurus. Moreover,
Temnopleurus toreumaticus, Klein, is living in the Persian Gulph, whilst Lehinus toreuma-
ticus, Leske, is found fossil only in the Coral Rag.

The ambulacral areas are narrow, and very well defined by the straight poriferous zones,
which form deep furrows at their sides; they are about one fourth the width of the inter-
ambulacral, and have two rows of round tubercles, about fifteen m each row, very regularly
arranged on the margins of the areas (fig. 3.) ; the tubercles at the base are much larger,
and more prominent; and on the upper surface, a zigzag line of granules separates the
marginal tubercles (fig. 3 /).

The poriferous zones are narrow and straight, and, in consequence of the thickness of
the sculptured plates, lie deeply sunk; the pores are unigeminal and oblique (fig. 3 /),
and there are seven pairs of pores opposite each inter-ambulacral plate; near the peristome
they are in ranks of threes.

The inter-ambulacral areas are four times as wide as the ambulacral; from the peri-
stome to the equator there are two rows of large, round tubercles, on smooth, prominent
bosses (fig. 3 @, 6, c); and around the areolas circles of granules are disposed (fig. 3 /),
which, when viewed in profile, are rather conspicuous (fig. 3 e). On the upper part of the
areas the plates exhibit a most singular structure (fig. 3 4,7); around the primary
tubercles there are a number of irregular elevations, in relief, resembling hieroglyphic
characters (fig. 3,7); and although there is a considerable uniformity in the general facies
of the sculpture, still scarcely are any two figures alike (fig. 3 4,7). It is this structure
which suggested Leske’s name, torewmaticus,* and Goldfuss’s name, Aieroglyphicus. The
plates are thick and broad, and there are only about seven in each column; the tubercles
at the base (fig. 3 z) are round, regular, and prominent, and form a remarkable contrast
to the toreumatic sculpture exhibited on the upper part of the areas.

The apical disc is large, and forms a prominence on the vertex; it is one third the
diameter of the test at the equator (fig. 34); the genital plates have an elongated, hepta-
gonal form, and are sculptured on the surface like the plates of the inter-ambulacral areas ;
the oviductal hole is pierced about the outer third (fig. 3 7); the ocular plates are promi-
nent and heart-shaped, the eye-hole is marginal, and the sutural lines between all the
elements of the disc are defined by deep depressions (fig. 3 ¢) ; the vent is sub-pentagonal,
and the madreporiform body is represented by a few granules on the surface of the right

antero-lateral genital plate.

* Toreuma, (ropevpa,) any work raised in relief.

25

188 GLYPTICUS.

The mouth opening is one half the diameter of the test, the peristome is unequally
decagonal, the notches are small, and the ambulacral are nearly twice as wide as the inter-
ambulacral lobes.

Affinities and differences.—As this is the only species of the genus Glypiicus found in
the English Oolites, it is impossible to mistake it: the thick test, with the hieroglyphic-
like markings on the plates of the inter-ambulacral areas, and of the genital disc, distinguish
it sufficiently from all others.

Locality and Stratigraphical position—The rich cabinet of the late Mr. Channing Pearce
contains three specimens of this species, collected from the Coral Rag of Calne, Wilts; and
in the Museums of York and Whitby I saw one specimen in each, which were collected
from Coralline Oolite of Malton.

In France, M. Cotteau collected it at Chatel-Censoir and Druyes from the Inferior
Coral Rag, and the calcareo-siliceous layers subordinate to it. According to M. Desor it
is found in the Corallien (Terrain a chailles) of the Swiss and French Jura, of Burgundy,
Wirttemberg, and Franconia. On the Continent it is a very abundant and characteristic
fossil of the Coral Rag, and is now recorded for the first time as a British urchin.

History.—Leske appears to have considered this species identical with Cidaris
toreaumatica, Klem, he says, “‘Convenit hic Kchinites omnino cum ipsa naturali Cidari
toreumatica, figura testae lineolis insculptis, ambulacris biporosis et ani structura, ut nulla
mihi relinquatur dutitatio, cum hujus esse specicei. Testa est calcareo spatosa, coloris
cinereo flavescentis ; nucleus calcareus griseus. In Lotharingia inventus est.”’*

Goldfuss figured and described it in his ‘ Petrefacta Germanix’ by the name Zehinus
hieroglyphicus. M. Agassiz, in his ‘Prodrome,’ placed it in the genus Arbacia,
but afterwards, in his ‘Echinodermes Foss. de la Suisse,’ proposed for this and other
congeneric forms, the genus Glypticus. In this work it is beautifully figured, and
described in detail as Glypticus heroglyphicus. It has lately been figured by Bronn in his
‘Lethza,’ by M. Cotteau in his ‘Etudes sur les Echinides Fossiles,’ and by M. Desor
in his ‘Synopsis des Hchinides Fossiles, and is now recorded for the first time as a
British fossil urchin.

* «Additamenta ad Kleinii dispositionem Echinodermatum,’ p. 156, pl. 44, fig. 2.

189

NOTES

On Fortien JURASSIC SPECIES OF THE GENUS GLYPTICUS, nearty ALLIED TO THE
BRITISH FORM, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EnGLIsH Oo.irttrs.

Guypticus Bureunpiacus, Michelin. Revue et Magasin de Zool., No. 1, 1853.
“A large and fine species: it has, below the wregular portion of the inter-ambulacral
areas, three or four very large tubercles.

“ Formation.—Oxfordien ferrugineux d’Estrochey pres Chatillon-sur-Seine.

“ Collection—Museum of Dijon: very rare.’ _Desor.

Guyrticus suncatus, Goldfuss. Syn. Echinus sulcatus, Goldfuss. Petrefact. Germaniz,
tabl. 40, fig. 18.
A small hemispherical urchin, with a flat base; tubercles very irregular ; on each inter-
ambulacral area there are two deep grooves; the apical disc is large.

Formation.—Coral Rag, Nattheim; Engelhardsberg (Franconia); the environs of
Vendome.

Collections. —Museums of Munich, Tiibingen, all foreign collections: very common.

190 MAGNOTIA.

Genus—MAGNOTIA, Michelin. 1858.

This genus was established by M. Michelin* for small urchins, closely resembling
Polycyphus, but which are distinguished from that genus by the arrangement of the pores
in the zones. The genus is thus defined by its learned author :

Test elevated, mflated, with a concave base, and numerous small, equal-sized, imper-
forate and uncrenulated tubercles in both areas.

The pores are disposed in single pairs from the disc to the circumference ; from thence
to the peristome they become crowded, and form many series.

The mouth is very large, and occupies much of the base; the peristome is unequally
decagonal, and, from the width of the ambulacral lobes, is almost pentagonal.

The apical disc is small, and the vent round.

The ambulacral areas are narrow; the inter-ambulacral areas have a deep median
depression, so that the test is divided into fifteen unequal lobes, of which the five ambu-
lacral are the smallest. In both areas the tubercles are arranged in oblique ranks.

The distinctive structural character between Magnotia and Polycyphus consists in the
arrangement of the pores, which are in simple pairs in A/agnotia, and form triple oblique
pairs in Polycyphus: 1 all other respects these urchins closely resemble each other.

The only English species of this small group was referred by me to the genus Aréacia
of Agassiz, when I first described it in my ‘ Memoirs on the Cidaridz of the Oolites ;’+ but
as there is much doubt about the true characters of that genus, I have placed it in
M. Michelin’s Wagnotia, of which it forms a good type.

Arbacia was a small group of the Ecurnrpa, proposed by Dr. J. H. Gray, in October,
1835,t for a section of the genus Lchznus, now living, in which, according to this author,
the body is depressed, the ambulacral areas are very narrow, the poriferous zones narrow
and straight, the pores in simple pairs, the ovarian and inter-ovarian plates middle sized,
and the anus covered by four valves. ‘The types of the genus cited by the author are
Echinus pustulosus, Leske, and Hehinus punctalatus, Lamk.

M. Desmoulins,§ in 1834, had proposed the genus Hchinocidaris for the same group,
and which he thus defined: ‘General form perfectly regular, circular; upper surface
depressed ; under surface slightly concave; areas very unequal; ambulacra always less
than one half the width of the inter-ambulacra; ambulacra complete, lanceolate, straight,

* «Revue et Magasin de Zoologie,’ No. 1, 1853.

+ ‘Annals and Magazine of Natural History,’ 2d series, vol. viii, p. 278.

t ‘Proceedings of the Zoological Society,’ part iii, p. 58; and ‘Philosophical Magazine,’ 3d series,
vol vil, p. 329, Oct., 1835.

§ «Tableau analytique des genres d’ Echinides,’ July, 1834. ‘Htudes sur les Echinides,’ p. 14.

FROM THE INFERIOR OOLITE. 191

bordered on each side with a single pair of pores; spiniferous tubercles as in Echinus.”
The six species included in this genus are all living.

M. Agassiz’s* definition of Ardacia differs very materially from that of the original
author. He confines it to “small, sub-spherical urchins, having the test covered by
numerous, small, smooth-based, imperforate tubercles, ranged in numerous rows on the
inter-ambulacral, and sometimes on the ambulacrai areas. Pores disposed in simple pairs.
Mouth circular, without deep notches. Apical disc narrow and ring-like.” All the
species enumerated in the ‘ Catalogue raisonné’ are Cretaceous and Tertiary fossils, and the
Arbacia of Gray are transferred to the genus Hehinocidaris, Desml., so that the Arbacia
of Agassiz is not the Ardacia of Gray, but a new group which required revision and a
distinct name. To avoid future confusion, one section now forms the genus Cottaldia,
Desor, another the genus AZagnotia, Michelin, whilst the original Ardacia of Gray are
placed in the Lehinocidaris of Desmoulins, as that genus was first established.

Macwnoria Forsusit, Wright. Pl. XIII, fig. 6 a, 4, ¢, d,e, f.

ArsBacia Forest. Wright, Annals and Magazine of Natural History, 2d series, vol. viii,
p. 278, pl. 13, fig. 4.
Ecurnus Forsesiz. Morris, Catalogue of British Fossils, 2d edit., p. 79.
— — Salter, Memoirs of the Geological Survey, Decade V, description of

pl. 4.
Maenortia Forsesii. Desor, Synopsis des Hchinides Fossiles, p. 115.

Test small, hemispherical, sub-pentagonal ; ambulacral areas straight, narrow, and of
uniform width throughout, with four rows of small, equal-sized, close-set tubercles ;
poriferous zones narrow, and sunk in a groove; pores unigeminal throughout; inter-
ambulacral areas wide, each divided into two lobes by a median depression, the surface of
the plates covered with numerous close-set, equal-sized tubercles ; base concave ; mouth-
opening large, situated in a depression ; apical disc small, prominent, and ring-shaped.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, three quarters
of an inch.

Description.—The test of this beautiful sub-pentagonal little urchin is divided into
fifteen unequal lobes; five of these, forming the ambulacral areas, are narrow, and ten

much wider, the divided inter-ambulacral areas, which have deep furrows corresponding
to the centro-sutural line, and dividing each area into two equal convex conical lobes; the

* «Catalogue raisonne des Echinides, Annales des Sciences Naturelles,’ 3™° serie, tome vi, p. 355.

192 MAGNOTTA.

entire surface of the plates of all the areas is covered with small, smooth, polished, equal-
sized tubercles, crowded closely together, and disposed in oblique lines (fig. 6/).

The ambulacral areas are narrow and prominent, and nearly of the same width
throughout ; they are furnished with four rows of tubercles, except at the apex of the area,
where there are only two rows (fig. 6/).

The poriferous zones form narrow, depressed, well-defined lines on the surface of the
test (fig. 6d); the pores are small, and strictly unigeminal throughout, and there are four
pairs of pores opposite each inter-ambulacral plate (fig. 6/).

The inter-ambulacral areas are upwards of four times the width of the ambulacral ;
each of these spaces is divided into two convex lobes by a well-defined longitudinal
depression, which extends from the base to the disc in the direction of the sutural line;
the narrow ambulacra, bounded by the deep poriferous zones, and the wide inter-
ambulacra, divided by median depressions, produce a remarkable lobed appearance on the
test of this little urchin (fig. 6a, 6); the surface of the areas is crowded with small,
smooth, equal-sized tubercles ; at the circumference there are from twenty-five to thirty
rows (fig. 6), but the number diminishes at the upper surface, where the areas contract,
and likewise at the base, where the tubercles are larger; it may be stated, as a general
character of this species, that the tubercles are crowded so close together in all the areas
that the surface of the plates is rendered invisible, and the test, when examined with a lens,
has a uniform granulated appearance (fig. 6 ¢, d).

The base is concave (fig. 6 ¢), and the tubercles are larger in this region; the mouth
opening is wide, and lies in a depression ; the peristome has a pentagonal form, from the
unequal size of the lobes. ‘The notches are not well exposed in the only good specimen I
possess.

The apical disc is small and prominent (fig. 6 a, 6); it has a ring-like shape, from the
smallness of the ovarial plates and the size and position of the oculars (fig. 6); the
anterior pair of ovarials are the largest, and the right plate carries a small spongy madre-
poriform body; the vent is transversely oblong (fig. 6¢), and the oviductal holes are
large.

Affinities and differences.—This urchin, at first sight, might be mistaken for Polycyphus
Normannus, Desor, from the Great Oolite, but it is more depressed and pentagonal, has a
more concave base, deeper areal depressions, smaller, more numerous, and closer-crowded
tubercles ; the ambulacra are narrower, and the pores in the zones are unigeminal. These
characters are sufficiently marked to prevent A/agnotia Forbesit being mistaken for
Polycyphus Normannus : Magnotia has the zones narrow and the pores unigeminal, Poly-
cyphus has the zones wide and the pores trigeminal.

Locality and Stratigraphical position.—This very rare urchin was collected in the
upper ragstones of the Inferior Oolite, at Dundry, near Bristol. ‘The two specimens in

.
FROM THE INFERIOR OOLITE. 193

my collection, and the fine series m the Bristol Museum, with one found by Mr. W. H.
Baily, are the only specimens I know.

History.—First figured as Arbacia Forbesiz, in my ‘Memoir on the Cidaridz of the
Oolites.’? It was afterwards referred by M. Desor, in his Synopsis, to the genus Magnotia,
and appears to form a good type of that new group; it is the only English example of
the genus we at present possess.

194

NOTES

On Forzricen JURASSIC SPECIES OF THE GENUS MAGNOTIA, NEARLY ALLIED TO THE
BRITISH FORM, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITES.

Maewnorra Nopor, Michelin. Rev. et Mag. Zool., No. 1, 1853.

Test hemispherical; ambulacra narrow, with four rows of tubercles ; inter-ambulacra
with twelve rows ; tubercles of both areas of a uniform size, and not sensibly increased at
the circumference ; mouth opening large, occupying the greater portion of the base.

Formation.—Inferior Oolite d’Avesne (Cote-d’Or).

Collection.—Museum of Dijon ; a single specimen, which forms the type of this genus.

Maewnotia noputosa, Minster. Syn. Hchinus nodulosus, Minst., in Goldfuss, Petrefact.
Germ., tabl. 40, fig. 16.

Test nearly hemispherical, more or less sub-pentagonal; ambulacra with four rows of
tubercles, diminishing to two; inter-ambulacra divided by a median depression, and
furnished with from eight to ten rows, disposed in slightly arched horizontal lines; the
tubercles are a little larger at the circumference, and much larger at the base; they are
nearly uniform in size in both areas ; mouth opening large ; apical disc very narrow, in the

form of a ring.
Formation.—Coral Rag of Baireuth, and Nattheim.

Collections. —Museums of Bonn, Tiibingen.

Maewnorta Jurassica, Cotteau. Syn. Arbacia Jurassica, Cotteau, tudes sur les Bchinides,
pl. 20, figs. 6—11.

Test small, flat below, inflated above; ambulacra with four rows of tubercles;
inter-ambulacra with ten rows; upper surface of the areas depressed, and naked in the
middle ; the horizontal series of tubercles in inclined rows; mouth opening large ; peri-

FOREIGN JURASSIC MAGNOTIAS. 195

stome slightly notched into ten nearly equal-sized lobes. This species is less granular
than the preceding, from which it likewise differs in having smaller tubercles at the base.

Formation.—Inferior beds of “ ’étage Corallien” at Chatel-Censoir (Yonne), d’Eccomoy

(Sarthe).

Collection —M. Cotteau: very rare.

MaGnoria DEcoRATA, Agassiz. Syn. Hucosmus decoratus, Agassiz. Cat. raisonné, Aun.
ro) ?
Sc. Nat., 3° série, tome vi, p. 356, pl. 15, figs. 12, 13.

‘Test small, hemispherical, depressed ; ambulacra so extremely narrow that there is
io}

°
only space for a single row of tubercles, arranged in a zigzag line, thus o ; inter-
fo}

(e)

ambulacra wide, with eighteen rows of tubercles, which do not form vertical and horizontal
series, but are arranged in oblique lines; the zigzag row of tubercles in the ambulacra
results from the alternate plates in the area carrying only one tubercle on each.

Formation.—Argovien (Formation y of Quenstedt), Leegern, Baden near Zurich, Lochen

(Wiirttemberg).

Collections.—Museums Zurich, Neuchatel, Bale.

196 POLYCYPHUS.

Genus—POLYCYPHUS, Agassiz. 1846.

This genus consists of small urchins, with a sub-globular or hemispherical form; the
sides and upper surface of the test are covered with numerous, small, equal-sized, imper-
forate tubercles, which form numerous vertical and horizontal rows; at the base of both
areas the tubercles are disproportionately large, when compared with those on the upper
surface.

The poriferous zones are wide and depressed, and the pores are arranged in triple
oblique pairs; near the peristome the pores are more numerous, and crowded.

The mouth opening is large; the peristome is pentagonal, the notches are shallow,
with wide ambulacral, and short inter-ambulacral lobes.

The apical disc forms a narrow ring, and the genital and ocular plates are small.

The wide inter-ambulacral areas are each divided into two lobes by a slight median
depression, so that the surface of the test in this genus is divided into fifteen nearly equal-
sized lobes.

Polycyphus very much resembles Magnotia in the general facies of the species, in the
size and ornamentation of the test, in its division by depressions into lobes, in the number of
small imperforate tubercles which crowd its surface, and the ring-like character of the apical
disc ; but Magnotia is distinguished from Polycyphus by the narrowness of the ambulacral
areas, and especially by having the pores strictly unigeminal throughout the narrow sunken,
poriferous zones. i

Polycyphus resembles Stomechinus in having the pores in triple oblique pairs; but is
distinguished by the number and general uniform character of the tubercles, arranged in
vertical and horizontal rows, and by having those at the base of the areas disproportion-
ately large when compared with the small tubercles on the upper surface. In Stomechinus
there is always a primary row of tubercles, and secondary rows; but in Polycyphus they
are in general uniformly of the same size. The peristome in Stomechinus is always very
deeply incised by large notches, whilst in Polycyphus the division of the peristome is but
feebly marked.

FROM THE INFERIOR OOLITE. 197
Potycypuus Normannus, Desor. PI. XIII, fig. 4 a, 4, ¢, de, f.

PoLycyPuus NopuLosus. Agassiz and Desor, Catalogue raisonné des Echinides, Annales des
Sciences Naturelles, 3™° serie, tome vi, p. 361, pl. 15, fig. 18.

ARBACIA NODULOSA. Wright, Annals and Magazine of Natural History, 2d series,
vol. vili, p. 279, pl. 13, fig. 3 a, b.

PoLtycyPHus NopDuLosus. Wright, Annals and Magazine of Natural History, 2d series,
vol. xiii, p. 178.

ECHINUS NODULOSUS. Morris, Catalogue of British Fossils, 2d edit., p. 79.

— — Salter, Memoirs of the Geological Survey, Decade V, pl. 4, p. 8.

Potycypuus Normannus. Desor, Synopsis des Echinides Fossiles, p. 117, tabl. 19,

figs. 4d—6.

Test circular, hemispherical above, flattened at the base; ambulacral areas a little more
prominent than the inter-ambulacral, with six rows of tubercles at the equator; inter-
ambulacra with fourteen rows of tubercles disposed in vertical and transverse lines;
tubercles of both areas smooth, round, and nearly of the same size; basal tubercles much
larger ; poriferous zones wide, pores in trigeminal ranks ; inter-ambulacra divided by slight
median depressions, and naked at the upper part of the centro-suture : apical disc small
and ring-like; base flat ; mouth opening large; peristome very unequally lobed.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, eleven
twentieths of an inch.

Description.—This pretty little urchin has been long confounded with dMJagnotia
nodulosa, Mister, from the Coral Rag of Nattheim, which it resembles much in its
general physiognomy, but is distinguished by the structure of its ambulacra and poriferous
zones, the pores in JZ. nodulosa being unigeminal, whilst in P. Vormannus they are
trigeminal: for this reason M. Desor has properly described it as a distinct species. Its
hemispherical test exhibits a disposition to assume a sub-pentagonal form, in consequence of
the prominence of the ambulacral areas (fig. 4 a, 6); the surface of the test is divided into
fifteen nearly equal lobes by the ten wide poriferous zones, and a median depression in the
centre of the inter-ambulacra (fig. 4 e) ; these lobular divisions are more marked in young
and small specimens than in old and large ones ; the ambulacral areas (fig. 4 0, e) are one half
the width of the inter-ambulacral, they have nine large tubercles at their base (fig. 4, e, /),
and six rows of small tubercles at their widest part (fig. 4 e), wnich gradually diminish to
four and two rows above (fig. 4 4).

The inter-ambulacral areas are twice the width of the ambulacral (fig. 4 4), and are each
divided by a median depression into two equal-sized lobes (fig. 4 c); they have from
twenty to twenty-four large tubercles at their base (fig. 4 ¢), and from twelve to fourteen
tubercles on the same line at their widest part (fig. 4 e), which gradually diminish by the
disappearance of the lateral rows to ten, eight, six, four, and two (fig. 4 4); the row on

198 POLYCYPHUS.

the centre of the plates alone extending from the peristome to the disc ; the tubercles on
the sides and upper surface of the ambulacra and inter-ambulacra are nearly of a uniform
size, and regularly arranged in a series of horizontal and vertical rows (fig. 4 /), so that
the tubercles are opposite each other, and do not alternate as in Magnotia.

The poriferous zones are wide and straight (fig. 4 6, c); the pores are arranged in
oblique trigeminal ranks (fig. 47) ; at the base they are more crowded (fig. 4 e), to fill up
the space between the ambulacral and inter-ambulacral areas.

The base is flat (fig. 4 e); the large mouth opening is nearly pentagonal, and hes
in a concavity, surrounded by the larger tubercles which occupy this region (fig. 4 c); the
peristome is feebly notched (fig. 4 c), and very unequally lobed, the ambulacral being three
times the length of the inter-ambulacral lobes.

The apical disc is small and prominent (fig. 4 6); the genital plates are all nearly of
the same size (fig. 4 7), and perforated near their apex; the ocular plates are small, and
the eye-holes marginal; the vent is transversely oblong (fig. 4 d), and the genital plates
form a prominent ring around it; the spongy madreporiform body is rather elevated, and
a few microscopic granules adorn the surface of the plates.

Afinities and differences.—In its general facies, this little lobed and nodulated urchin
resembles Magnotia Forbesit, but in the details of its structure it is very distinct from that
form; thus its ambulacral areas and poriferous zones are wider, the median inter-
ambulacral sulcus is shallower and not so defined, the tubercles are larger and arranged
in a series of vertical and horizontal rows, and the pores are disposed in oblique trigeminal
ranks ; the test is likewise more hemispherical and inflated, and wants the marked sub-
pentagonal outline, the narrow furrowed zones, and deep median sulci which so well
characterise Wagnotia Forbesi.

Locality and Stratigraphical position.—This species is very rare in England. I have
collected one specimen from the 'l'rigonia grit, Inferior Oolite, near Hampen ; Mr. Jones
found another near Birdlip, in the same rock ; the Rev. P. B. Brodie collected one specimen
from a bed of clay resting on the Stonesfield slate at Sevenhampton, associated with
Acrosalenia spinosa and Pecten varians ; Mr. Lycett obtained several from the Great Oolite
of Minchinhampton Common; these are the only specimens known to me which have
been collected in Gloucestershire. Mr. William Buy found a beautiful specimen in the
Cornbrash near Sutton-Benger, Wilts, which is in my collection. He informs me that it
is the only example of this urchin he has found. It was associated with Acrosalenia
hemicidaroides, Acrosalenia spinosa, and other Cornbrash fossils; so that the range of this
species is from the upper ragstones of the Inferior Oolite through all the intermediate beds
into the Cornbrash, where it becomes extinct.

On the Continent it is more abundant. It has been collected from the Great Oolite
of Langrune and Luc by Professor Deslongchamps and M. Tesson ; and from the Calcaire
a polypiers at Ranville by M. Michelin. I have to thank each of these gentlemen for the

FROM THE INFERIOR OOLITE. 199

beautiful series of type specimens they have sent me for comparison, and which are
perfectly identical with our English forms.

History.—First entered in the ‘ Catalogue raisonné des Kchinides’ of Agassiz and Desor
as Polycyphus nodulosus, under the supposition that it was identical with Miinster’s
species from Nattheim; a more pentagonal form was afterwards figured by me in the
‘ Annals of Natural History,’ under the name of Arbacia nodulosa. M. Desor has the merit
of having shown that it is even generically distinct from the German urchin, which
has narrow zones and unigeminal pores; whereas our species has wide zones, and the
pores in oblique trigeminal ranks. M. Desor has therefore described and figured it as a
distinct species, under the name Polycyphus Normannus.

Potycypaus DesLonecuampsil, Wright. Pl. XIII, fig. 5 a, 4, ¢, d, e, f.

Potycypuus DesLonecHampsii. Wright, Annals and Magazine of Natural History, 2d series,
vol. xiii, p. 179, pl. 12, fig. 4.
= — Morris, Catalogue of British Fossils ; additional species of
Echinodermata.

Test small, hemispherical, and circular; ambulacral areas with two rows of large, and
two rows of smaller tubercles; inter-ambulacral areas divided into lobes by a median
depression, and provided with two rows of large, and several rows of smaller tubercles,
the small tubercles often degenerating into granules; basal tubercles large and prominent ;
apical disc prominent.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, thirteen
twentieths of an inch.

Description —Amongst the many beautiful forms of Ecuin1p# found in the Oolitic
rocks, this pretty little species will bear comparison for neatness and symmetry with any
of the family to which it belongs. I first found a solitary specimen of this species about
four years ago, and since then have obtained an interesting series of different ages ; but it
is a very rare species.

The ambulacral areas are one half the width of the inter-ambulacral (fig. 5 4, d); they
have two rows of tubercles set closely and regularly together on the extreme margins of
the areas (fig. 5 4, f); between these are two shorter, immer rows, which do not extend
more than two thirds the length; at the base of the area ten large tubercles are disposed

200 POLYCYPHUS.

in pairs (fig. 5 c, d), those on the right alternating with those on the left side of the
area.

The inter-ambulacral areas are twice the width of the ambulacral (fig. 5 4, @) ; a single
row of larger tubercles, about sixteen in each row, is placed in the centre of each of the two
columns of plates (fig. 5 7); and numerous smaller tubercles, degenerating into granules,
occupy the rest of their surface (fig. 5 7); a second row of tubercles extends from the base
to the circumference, where it terminates (fig. 5 c, d); the tubercles at the base of the
inter-ambulacra are about the size of those occupying the same region in the inter-ambu-
lacra; there are twelve of these larger tubercles in each area, so that the base (fig. 5 c) has
a much more granulated appearance than the upper surface of the test (fig. 5 6); as
the median sulcus in the centre of the inter-ambulacra is sharply defined, and the pori-
ferous zones are much sunk, the surface of the test is thereby nearly equally divided into
fifteen lobes.

The poriferous zones lie in considerable depressions (fig. 6, d); the pores are very
indistinct, and arranged in oblique trigeminal ranks; between each rank a small tubercle
is developed, which adds to the granulated aspect of this region, and renders the situation
of the pores still more difficult to trace (fig. 5 /).

The apical disc is small and prominent (fig. 5 a, 4), the genital plates are nearly of
the same size (fig. 5 e), the spongy madreporiform body is small, and the oviductal holes
are pierced near the margin; the ocular plates are small and heart-shaped, and the eye-
holes are distinctly marginal; the vent is small, and transversely oblong.

The base is flat (fig. 5 7), and remarkable for the much greater size of the tubercles
in this region than on the upper surface; the mouth opening is one half the diameter of
the test, and the peristome is divided by feeble notches into ten unequal lobes (fig. 5 c.)

Affinities and differences—In its general facies, this species resembles Polycyphus
Normannus, but is readily distinguished from it by the marginal tubercles on the ambu-
lacra, the two central rows of larger tubercles on the imter-ambulacra, and the smaller
tubercles crowded around their base (fig. 5 7); by the row of tubercles between the
trigeminal ranks of pores, the comparatively small number of tubercles in the inter-am-
bulacra, and the greater size of the central rows. ‘The tubercles at the base are likewise
much larger in Polycyphus Deslongchampsit.

Locality and Stratigraphical position.—I collected this urchin in the Pea-grit at
Crickley Hill, with Diadema depressum and Acrosalenia Lycettii. Myr. Gibbs, of the
Geological Survey, found a few specimens in the same rock and locality.

I have dedicated this species to Professor Deslongchamps, of Caen, to whom palzeon-
tologists are indebted for many valuable memoirs on the Oolitic fauna, published in the
‘Mémoires de la Société Linnéenne de Normandie.’

201

NOTES
ON
ForEIGN JURASSIC SPECIES OF THE GENUS POLYCYPHUS, nearty ALuiep To Britisa

FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EnGLisH OoLitss.

PoLycYPHuUs STELLATUS, Agassiz. Catalogue raisonné, Annal. Sc. Nat., tome vi, 3"° série,
p- 361.

It closely resembles P. Normannus, but has fewer tubercles in the inter-ambulacral

areas. ‘The type specimen, sent me by M. Michelin, appears to be only a variety of that
species.

Formation.—Great Oolite of Ranville, Calvados.

Collections —MM. Deslongchamps and Michelin: rare. My cabinet.

Potycypuus coraLLinus, Cotteau. Etudes sur les Echinides, pl. 21, figs. 1—7.

A large, fine species, hemispherical above, and flat below; the narrow ambulacra,
with two very regular rows of marginal tubercles, and a third row in the middle; the
inter-ambulacra large, with a naked median depression; ten rows of tubercles at the
equator, diminishing to two above, the horizontal rows slightly inclined. ‘The promi-
nence and regularity of the ambulacral tubercles forms a distinctive character of this
beautiful species.

Formation.—Jura moyen “ (Calcaire a chailles) des environs de Druyes: cette espéce
est fort rare.” Cotteau.

Collection.—M. Cotteau.

202 FOREIGN JURASSIC POLYCYPHUS.

PoLycyPHUS DISTINCTUS, Agassiz. Syn. Hehinus distinctus, Agassiz. Cat. raisonné, An.
Sc. Nat., tome vi, 3™° serie, p. 366.

“A very large depressed species ; inter-ambulacra with from ten to twelve rows of
tubercles; ambulacra with four rows of tubercles, the two internal rows much more

uregular than the external.

“ Formation.—Corallien d’Angoulin pres la Rochelle.

“ Collection.—M. WOrbigny : rare.” Desor.

STOMECHINUS. 203

Genus—STOMECHINUS,* Desor. 1854.

M. Desor has separated from the genus Hchinus all those urchins which have a large
mouth opening, with the peristome nearly pentagonal, through the great development of the
ambulacral, and the rudimentary size of the inter-ambulacral lobes; and which have
two wide, deep notches at each of the five angles of the pentagon.

This new genus or section of the Ecxu1nrpm is composed of urchins of moderate size,
having a hemispherical, globular, or conoidal test, which is sometimes more or less depressed
in different species.

The ambulacral areas are about one third the width of the inter-ambulacral, having
two marginal rows of small tubercles, from twenty to thirty in each row, and sometimes
two additional internal rows, in general smaller than those of the other segments.

The inter-ambulacral areas have two principal rows of tubercles in the centre of the
plates, and several secondary rows, at their sides, often as large as the principal ones; the
miliary zone is sometimes broad and granular, or narrow, depressed, and more or less
naked.

The apical disc is small, the genital plates are nearly equal-sized, and the spongy
madreporiform body is large and promment on the surface of the right anterior genital
plate.

The mouth opening is large, the peristome is deeply notched at the base of the inter-
ambulacral areas ; the pairs of notches approach each other so close, that they leave only a
small triangular lobe between them; the length of the ambulacral lobes is such, that it
produces a pentagonal-shaped mouth; the notches have the margin reflected at each of
the angles. |

The poriferous zones are moderately wide, and the pores are arranged in triple oblique
pairs, as in the genus Lehinus.

The spines are small, short, stout, and blunt pointed; their surface is covered with
well-marked longitudinal lines.

This genus is extinct, and appears to be limited to the Oolitic formations. The species
are found in the Inferior Oolite, Great Oolite, Cornbrash, Coral Rag, Kimmeridge Clay,
and Portland Oolite; they, however, attained their greatest development in the lower
division of the Oolites.

* From eroua, mouth.

27

204 STOMECHINUS.

A. Species from the Inferior Oolite.

STOMECHINUS GERMINANS, Phillips. Pl. XIV, fig. 1, a, 6, ¢, d.

EcHINUS GERMINANS. Phillips, Geology of Yorkshire, pl. 3, fig. 15, p. 127.
— _ Murchison, Geology of Cheltenham, 2d edit., p. 73.
— — Morris, Catalogue of British Fossils, p. 52.
— PERLATUS, var. GERMINANS. Wright, Annals and Magazine of Natural History,
2d series, vol. viii, pl. 13, fig. 1 a—d, p. 274.

— DIADEMATA. M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. u, p. 410.
— PERLATUS. Forbes, in Morris’s Catalogue of Brit. Foss., 2d edit., p. 79.
—_— — Salter, Memoirs of the Geological Survey, Decade V, pl. 4.
STOMECHINUS GERMINANS. Desor, Synopsis des Echinides Fossiles, p. 126.

— SUB-coNoIDEUS. Desor, Synopsis des Echinides Fossiles, p. 125.

Test high, conoidal; marginal fold acute, circumference sub-pentagonal; ambulacral
areas with two rows of primary tubercles, thirty-four im each row; poriferous zones wide,
the trigeminal ranks lie very obliquely across the zone; inter-ambulacral areas with one
central row of primary tubercles in the middle, two rows of secondaries on the zonal, and
one on the centro-sutural side of each column of plates; miliary zone wide and finely
granulated, with a naked median depression in the upper half; apical disc small, excentral ;
genital plates very narrow, vent transversely oblong, base concave; mouth opening very
large ; peristome pentagonal, with bifid-notched angles, the ten notches wide and deep.

Dimensions.—Height, one inch and a half; transverse diameter, two inches.

Description —Since the publication of my ‘ Memoir on the Cidaride of the Oolites,’
im which this urchin was first described, I have obtained specimens of Hchinus perlatus,
Desmarest, which has enabled me to make a critical comparison between our specimens
and the species to which it was referred, and I have thereby been enabled to correct errors
im my previous determination.

The test of Stomechinus germinans, especially in adult specimens, is always high and
conoidal (fig. 1 a); the sides rise abruptly from an acute marginal angle; the prominence
of the ambulacra, and the median depression in the inter-ambulacra, impart a lobed
appearance to its upper surface.

The ambulacral areas are one third the width of the inter-ambulacral (fig. 1 a, ¢) ;
they are very uniform in breadth throughout, and from being convex and prominent,
give a sub-pentagonal form to the circumference; they have two rows of tubercles on
their margins, from thirty to thirty-four in each row, a smaller tubercle often alternating

FROM THE INFERIOR OOLITE. 205

with a larger one (fig. 1 c); the tubercles of the ambulacra are smaller than those of the
inter-ambulacra ; they are raised on small bosses, and surrounded by depressed, ring-shaped
areolas (fig. 1 c), which are bounded on one side by the poriferous zones, and on the
other by a row of small lateral granules; between the two rows of granules there is a
naked space (fig. 1 ¢), in which the suture is distinctly seen ; towards the base of the area
this space is filled with other rows of granules, and from four to six large tubercles, which
extend round the angle to the base (fig. 1 4), where the marginal tubercles are disposed
with great regularity, surrounded on each side by trigeminal ranks of pores, which le at
angles of 20° across the wide zonal space (fig. 1 @).

The poriferous zones are of a uniform width on the sides; they are slightly contracted
at the angle, and again expand at the base; the trigeminal ranks of pores are disposed
very obliquely across the zones, at angles of from 30° to 40°; there are three small
granules between each rank (fig. 1 ¢), and each pair of pores is surrounded by an oval
elevation of the test; the pores of each pair are placed obliquely upwards, and there are
about five trigeminal ranks opposite every two large plates, which, estimating twenty-eight
plates in a column, gives about seventy triple oblique pairs of pores in each zone.

The inter-ambulacral areas are three times the width of the ambulacral; they are
composed of long, narrow, pentagonal plates, of which there are twenty-eight im each
column of an adult shell; each area has two rows of primary tubercles in the centre of the
plates, which extend from the peristome to the apical disc (fig. 1 a); between this row and
the poriferous zones there are two rows of secondary tubercles, which become rudimentary
half way up the sides; between the primary row and the centro-suture there is another
short row of six or seven secondaries (fig. 1 a, c); the tubercles are raised on small bosses,
which are surrounded by depressed areolas, and the granules of the miliary zone form
complete circles around them.

On the upper half of the area there is a well-marked median depression, which divides
it into halves; the depression is naked, but the rest of the wide inter-tubercular space is
covered with numerous granules (fig. 1 @).

The marginal fold in this species forms an acute angle; the base is concave, and
crowded with large tubercles, the secondaries being as large as the primary rows in this
region of the test (fig. 1 4). |

The mouth opening is very large, nearly one half the diameter of the base; the
peristome is pentagonal, with two wide and deeply incised notches at each angle, opposite
the base of the inter-ambulacral areas (fig. 1 4); between these the short lobe is rounded,
and the margins of the large ambulacral lobes form double curved lines (fig. I 4, d).

The apical disc is small and excentral; it is placed backwards, and projects into the
single inter-ambulacrum; the genital plates are very narrow, the anterior pair being
larger than the posterior pair; the right antero-lateral plate, with the prominent spongy
madreporiform body, is the largest, and the posterior single plate the smallest; the
oviductal holes are pierced near the apex ; the ocular plates are small and heart-shaped,

206 STOMECHINUS.

and the minute eye-holes appear like slits near the border; the vent is transversely
oblong, or has sometimes an irregular form (Pl. XIV, fig. 1 a).

The spines are small, delicate, and subulate, but are very seldom found in connection
with the tubercles. I have seen them twice when cleaning specimens, but unfortunately
they have fallen off in drying.

Afinities and differences.—This is the true Echinus germinans, Phillips. Through the
kindness of Mr. Reed, of York, I possess two specimens of the type urchin, collected by
him at Whitwell, which I have critically compared with our specimens, and found them to
be identical. This species is certainly distinct from Mchinus perlatus, Desmarest, which
has smaller and more numerous tubercles in the inter-ambulacra, narrower poriferous
zones, and wider ambulacra, than Stomechinus germinans.

It differs from Stomechinus intermedius (Pl. XIV, fig. 2), which is considered by some
to be a mere variety of S¢. germinans, in having a more elevated and conoidal test, larger
tubercles, narrower and more prominent ambulacra, the apical disc more excentral, the
marginal angle more acute, the mouth opening larger, and the notches wider, with deeper
incisions ; but the two forms are unquestionably most nearly allied, and it is only when
placed side by side, and closely compared, that the differences become evident.

It differs from Stomechinus bigranularis (Pl. XIV, fig. 3) in all the structural details
already referred to, in the comparison with St. cntermedius ; but im addition to these, the
globose test, with its inflated sides and convex base, so characteristic of S¢. digranularis,
added to the small mouth opening which this species possesses, enables us to distinguish
it readily from S¢. germinans; as I shall have to return to these affinities and differences
when treating of both forms, I reserve further details until the respective species are the
subject of our special study.

Locality and Stratigraphical position.—I have collected this species in the Pea-grit of
Leckhampton, Birdlip, and Crickley Hills, and it is found in the freestone beds of the
Inferior Oolite at Nailsworth and Wallsquarry, Gloucestershire. In Yorkshire it is
collected from the freestone beds of the Inferior Oolite at Whitwell, near Castle Howard.
‘These beds have been considered to be Great Oolite, but I am of opinion they are
true Inferior Oolite, as Mr. Reed obtaimed, at Whitwell, with Stomechinus germinans,
Gervilia Hartmanni, Miunst., the large quadrate Inferior Oolite variety of Z'rzgonia costata,
Sow., and other well-known Inferior Oolite shells. It is by mistake that this urchin has
been said to be found in the Corallme Oolite at Malton, as I shall endeavour to show in
the history of the species. ‘The Achinus diademata, M‘Coy is a small Whitwell specimen
of St. germinans. From the facts before me, I conclude that this is a true Inferior Oolite
species, and the first and most typical of the genus to which it is referred.

History.—This urchin was first figured by Professor John Phillips, in his ‘ Geology of

FROM THE INFERIOR OOLITE. 207

the Yorkshire Coast,’ in his plate of Coralline Oolite fossils, and was said to be collected
from the Great Oolite at Whitwell, and the Coralline Oolite of Malton and Scarborough.
The statement that it occurred in the Coral Rag led both Professor Forbes and myself to
suppose that it might be a variety of Hchinus perlatus, and under this impression it was
described as such by us both. Since the publication of my Memoir, I have visited most
of the typical collections of Yorkshire fossils, with the view of determining some doubtful
points relative to the stratigraphical position of certaim species, and from this examination
I am satisfied that Stomechinus germinans has not been found out of the Inferior (Great ?)
Oolite of Whitwell and other Inferior Oolite localities. The statement that it came from
Malton was first made by a collector who obtained the specimens at Whitwell, and sold
them as Malton fossils. Myr. Reed, of York, who was acquainted with the facts, writes me
as follows: ‘There cannot, I think, be a doubt as to the correctness of your previously
strongly expressed opinion regarding the distribution of Lchinus germinans, Phil., and
Clypeus semisulcatus, Phil., in the Oolitic beds, very eaclusively in the lower series, and
not both in the latter and Coralline Oolite, as stated by Professor Phillips in his work on
the ‘ Geology of Yorkshire.’ From long experience I am decidedly of opinion that neither
species have ever been found in the Coralline Oolite at Malton or the neighbourhood. ‘The
error originated from the fact of a local collector, named Larcum, having sold the speci-
mens which he obtained at the different quarries, and from different strata, six or eight
miles round Malton, as Malton fossils. He was in the habit of procuring his specimens
from the Great Oolite of Whitwell and Weston, also from some quarries at or near
Coneysthorpe, most probably Inferior Oolite, and from the Calcareous grit at Appleton,
as well as from the Coralline Oolite of Malton. I may also remark that he was wholly
ignorant of geology, and I know, from personal experience, that he was unacquainted with
the distribution and names of the Oolitic beds in the neighbourhood, having for many
years obtained fossils from him. He was, I believe, the exclusive dealer in Malton for
more than half a century.”

Professor M‘Coy described* a specimen of this species as Hchinus diademata, from the
Coralline Oolite of Malton. ‘Through the kindness of Professor Sedgwick I have been
enabled to examine this specimen, belonging to the Cambridge Museum, and have com-
pared it with my Whitwell specimens, and there cannot be a doubt of their identity.

‘This species was first figured by Professor Phillips, in the ‘ Geology of Yorkshire,’ as
Echinus germinans. It was afterwards figured and described, for the first time, in my
‘Memoir on the Cidaride of the Oolites,” as Hchinus perlatus, var. germinans. Pro-
fessor Forbes, in Morris’s ‘ Catalogue,’ and in lettering Pl. IV, Decade V, of the ‘ Memoirs
of the Geological Survey,’ retained the same name. Mr. Salter, in his elaborate article
on this urchin, in the same work, describes it as Hehinus perlatus.

>

* «Annals and Magazine of Natural History,’ 2d series, vol. ii, p. 410.

208 STOMECHINUS.

STOMECHINUS INTERMEDIUS, Agassiz. Pl. XIV, fig. 2 a, 4, ¢, d.

EcHINUS INTERMEDIUS. Agassiz, Catalogus systematicus Ectyporum Echinodermatum,
Do I,
— GRANULARIS. Wright, Annals and Magazine of Natural History, 2d series,
vol. vii, p. 277.

Test hemispherical, depressed, inflated at the sides, nearly circular at the circumference,
sometimes inclining to a sub-pentagonal form; ambulacral areas with two rows of small
tubercles on the margins, and a miliary zone between; poriferous zones wide; trigeminal
ranks very oblique; inter-ambulacral areas with two entire primary, and four short
secondary rows of small tubercles; miliary zone very wide, and covered with small
granules ; apical disc slightly excentral, of moderate size, genital plates fully developed ;
mouth opening large; peristome pentagonal, with two small notches at each angle;
inter-ambulacral areas slightly depressed at the centro-suture.

Dimensions.—Height, one inch and one fifth; transverse diameter, one inch and nine

tenths.

Description —Through the kindness of Professor Deslongchamps, I possess a type
specimen of Hchinus intermedius from the Great Oolite of Ranville, and which fossil was
determined by M. Agassiz. This specimen has enabled me to distinguish the urchin
mentioned in the ‘ Catalogue raisonné,’ and entered as var. major of Mchinus bigranularis,
Lamarck, in that memoir.

It is certainly very difficult to describe the nice distinctions between the first three
species, beautifully and truthfully drawn in Pl. XIV, as they graduate into each other
so insensibly, that it is almost impossible to seize their distinctive characters ; so much so,
that at one time I considered them varieties of one species; having, however, examined a
great many specimens of these Hchini, I am satisfied that if varieties, they are permanent
ones, and as such require a separate description. Their structural characters, however,
are sufficiently marked to justify their separation into distinct species.

The test of Stomechinus intermedius is hemispherical, but rather depressed above ; the
sides are a little inflated, the marginal angle is obtuse, and the base is flat (fig. 2c); the
ambulacral areas are one third the width of the inter-ambulacral; they have two marginal
rows of small tubercles, about thirty im each row, arranged with regularity on the margins
of the areas (fig. 2 a, d); these tubercles have small bosses, and narrow areolas, which are
encircled by minute granules; there are two rows of granules between the tubercles and
the suture (fig. 2 7), which extend through the entire length of the area.

The poriferous zones are wide, the trigemimal ranks incline at about 40°; three small
tubercles are placed between each rank (fig. 2 ¢), and there are two ranks opposite each

FROM THE INFERIOR OOLITE. 209

inter-ambulacral plate ; the zones are slightly contracted at the margin, and expand again
at the base.

‘The inter-ambulacral areas are three times as wide as the ambulacral (fig. 2 c); each
column consists of about twenty-five elongated, pentagonal plates (fig. 2 7), anda median
depression divides the area from the margin to the disc into two lobes ; there are two rows
of small primary tubercles in the centre of the plates (fig. 2 ¢, d), which extend from the
peristome to the disc, and two short rows of secondaries on their zonal sides, which dis-
appear a little way above the margin; within the primary rows at the base are six or
seven more ; from the circumference to the disc there is a wide miliary zone (fig. 2 a, o),
which is filled with small tubercles and minute granules, arranged, however, with con-
siderable regularity on the plates (fig. 2 d), and extending even over the median depression,
which, when taken in connection with the smallness of the tubercles, about the same size
in both areas, imparts a peculiar granular appearance to the test of this species.

The base is flat, and the tubercles, as usual, are larger in this region; the mouth
opening is eight tenths of an inch, the diameter of the test being one inch and nine tenths ;
the peristome is pentagonal, with two notches at each angle, and a small lobe between,
the large ambulacral lobes forming the sides of the pentagon (fig. 2 4).

The apical disc is well developed, and slightly excentral (fig. 2 ¢); the genital plates
(fig. 2 a, e), are elongated, and perforated near their outer third, the right antero-lateral
being much the largest, and supporting a prominent madreporiform body (fig. 2 e); the
ocular plates are small pentagons, with slit-like eye-holes ; the disc is much more developed
in this species than it is either in Stomechinus germinans or bigranularis.

Affinities and differences—This urchin is distinguished from Stomechinus germinans
by the following characters: The test is more regular in its form, less elevated and
rounder, and never assumes a conoidal figure; the tubercles are much smaller, and equal-
sized; the small tubercles and granules on the miliary zone are larger, and have a more
regular arrangement, which, with the smallness of the primary tubercles, gives the test a
more granular facies. The marginal angle is more obtuse, and the sides are inflated; the
apical disc is larger, and its elements are more developed; the mouth opening is pro-
portionally smaller, and the notches are neither so wide nor so deeply incised. Sfo-
mechinus intermedius is considered by MM. Agassiz and Desor to be a variety of S¢.
bigranularis ; but, between the structure of the apical disc, the arrangement of the
trigeminal ranks in the poriferous zones, and in the size of the mouth opening, we find
characters sufficient to show that the affinity between S¢. germinans and St. intermedius is
greater than between S¢. intermedius and St. bigranularis.

Locality and Stratigraphical position.—I have collected this species in the upper rag-
stones of Shurdington, Rodborough, and Dundry Hills, where it is extremely rare. The
Dundry specimen I formerly described under the name of Lchinus granularis. I found a

210 STOMECHINUS.

beautiful specimen in the Trigonia grit of Hampen, Gloucestershire, with Pedina rotata,
Hfolectypus depressus, and Collyrites hemisphericus. The Rev. A. W. Griesbach collected
one specimen in the Cornbrash, at Rushden, Northamptonshire ; and Mr. Buy obtained
another from the Cornbrash, near Sutton, Wilts.

STOMECHINUS BIGRANULARIS, Lamarck. Pl. XIV, fig. 3.a, 6, ¢, d, e.

ECHINUS BIGRANULARIS. Lamarck, Animaux sans Vertébres, tome iii, p. 50.
— — Agassiz and Desor, Catalogue raisonné des fchinides, Annal.
des Sciences Naturelles, 3™° série, tome vi, p. 365.
— SERIALIS. Wright, Annals and Magazine of Natural History, 2d series,
vol. vili, p. 276, pl. 13, fig. 2.
= — Forbes, in Morris’s Catalogue of British Fossils, 2d edit., p. 79.
— PERLATUS, var. Forpesiz. Salter, Memoirs of the Geological Survey, Decade V,
pl. 4, fig. 6.
STOMECHINUS BIGRANULARIS. Desor, Synopsis des Echinides Fossiles, p. 125, tab. xviii,
fig. 5—7.

Test hemispherical, depressed ; sides inflated, circumference more or less sub-penta-
gonal; ambulacral areas with two rows of small tubercles on the margins, placed wide
apart, twenty-six in each row, and a very fine granulation between; poriferous zones
narrow, trigeminal ranks not very oblique, becoming nearly parallel on the upper and
under surfaces ; inter-ambulacral areas with two rows of primary tubercles, twenty in each
row, and two short rows of secondaries, which disappear at the circumference; miliary
zone wide, and uniformly covered with small, equal-sized granules; mouth opening small ;
peristome pentagonal, with ten shallow, obtuse notches; apical disc large, excentral ; all
the genital plates, with the exception of the right antero-lateral, small; vent large, and
encircled by a moniliform line of small granules.

Dimensions.—Specimen a, fig. 3a. Height, one inch and one fifth; transverse
diameter, one inch and seven tenths.
a B, fig. 36. Height, one inch and seven twentieths; trans-

verse diameter, two inches.

Description.—This species is supposed to be Behinus antiquus, Defrance MSS., and
Echinus bigranularis, Lamarck, although this is not quite clear, M. Desor says—
‘‘T have been for a long time in doubt as to the identity of this species, which was so
much more difficult to define, as, among the originals in the Paris Museum, ticketed by the
hand of Lamarck, there are found many species. After much hesitation, I propose to

FROM THE INFERIOR OOLITE. 211

restrict the name digranularis to the Oolitic species, so well figured by M. Wright under
the name seria/is, and afterwards by M. Forbes.”* I am the more disposed to accept
this determination, as I have a beautiful specimen of this species from the Ferrugenous
or Inferior Oolite of Croisilles, Calvados, kindly sent me by M. Michelin as Hehinus
bigranularis, Agassiz, and determined by him, which exactly corresponds with our English
specimens.

I have been fortunate in obtaining a fine series of this urchin, which has enabled me
to study the variations it presents at different periods of growth; with the exception
of some forms being more globular, others more pentagonal, all its essential characters are
extremely persistent in my specimens.

The test is sometimes globular, but in general hemisperical and depressed; the cir-
cumference is occasionally round, but oftener sub-pentagonal, and varies in size from one
to two inches in diameter. The specimen figured is an extremely pentagonal variety, and
was selected because the tubercles and sculpture of the test were finely preserved
(fig. 3 a, ¢).

The ambulacral areas are narrow, and nearly of a uniform width throughout; they
have two rows of small tubercles, placed wide apart on the margins, of which there are
twenty-six in each row (fig. @, c); every alternate plate in the column carries a tubercle,
which alternates with a plate covered with two rows of small granules (fig. 3 d); at the
base the tubercles are larger (fig. 34), and in the middle two rows of small granules
separate the marginal tubercles (fig. 3 d).

The poriferous zones are narrower than in S?. germinans and St. intermedius ; the
trigeminal ranks incline at angles of from 55° to 60°; they become more sub-parallel on
the upper part of the zones, and towards the base; there is one small tubercle at the angle
between each file (fig. 3 d) of pores, and there are five trigeminal ranks opposite two
tubercular plates.

The inter-ambulacral areas are three and a half times as wide as the ambulacral
(fig. 3, a, c) ; the plates are broader than in the preceding species ; and consequently there are
only from twenty to twenty-two plates in a column. ‘There are two rows of primary
tubercles, which are placed nearer the poriferous rows than the centro-suture (fig. 3 ¢) ;
they are a little larger than the ambulacral tubercles, and nearly of the same size from the
circumference upwards. A row of smaller secondary tubercles, about twelve in number,
occupies their zonal side, and extends half way up the test (fig. 3c). The tubercles are
raised on bosses (fig. 3d), surrounded by narrow, ring-like areolas, a series of small
granules encircle the base, and the remaining surface of the plates is dotted over with
numerous smal] equal-sized granules (fig. 3d). ‘There is a very slight median depression,
from the upper part of which the small granules are absent (fig. 3a). At the base of the
area six larger tubercles are disposed within the primary rows (fig. 3 4).

* «Synopsis des ehinides Fossiles,’ p- 125.

28

212 STOMECHINUS.

The base is flat, and, as all the tubercles are of an equal size, this region of the test
presents a remarkable tuberculous character (fig. 3 4), when compared with its smooth
upper surface (fig. 3a); the mouth opening is much smaller than in S¢. germinans and
St. intermedius ; thus, in fig. 3 6, the diameter of the test is nearly two inches, whilst the
width of the mouth is seven tenths of an inch; in fact, the smallness of this opening is one
the most important diagnostic characters of the species, and becomes very evident when
we compare fig. 26 and fig. 1 a, with fig. 34; this comparative smallness of the mouth
is a persistent character in all the specimens I have examined, the peristome is pentagonal,
with two obtuse notches at each angle.

The apical disc is of moderate size and slightly excentral, projecting backwards into the
single inter-ambulacrum (fig. 3c); the anterior pair of genital plates are larger than the
posterior pair. The right plate, with the madreporiform body, is the largest, and the
posterior single plate the smallest (fig. 3a, e). On the surface of each of these plates, the
anterior right plate excepted, there are six or seven small tubercles arranged, which
collectively form a moniliform ring about the margin of the vent (fig. 3 e), which is
extremely large in this species, and projects slightly towards the left side of the body; the
ocular plates are small, and the eye-holes like oblong slits (fig. 3 @).

Afimties and differences.—In the general form and physiognomy of the test, this species
resembles Stomechinus intermedius; it is distinguished from that species, however, by
having fewer ambulacral and inter-ambulacral tubercles, the poriferous zones narrower,
the trigeminal ranks of pores more upright, and the mouth opening much smaller.
The apical disc is larger, the anal opening much wider, with a circle of granules around
its margin; on the miliary zones the granules are likewise smaller and more numerous.
The same group of characters serve to distinguish it still more distinctly from
St. germinans.

M. Desor and M. Agassiz consider St. intermedius as a variety of St. brgranularis ; but
from this opinion I must beg to differ, because, although S¢. germinans and St. tatermedius
may possibly be varieties of one species, still assuredly S¢. dcgranularis is distinct from both ;
the smallness of the mouth opening, the structure of the apical disc, and the greater
breadth of the inter-ambulacral plates, in my judgment, justify the distinction.

Locality and Stratigraphical position.—I have collected this species only from the
Upper Ragstones of the Inferior Oolite near Bridport, in Dorsetshire, associated with
Holectypus hemisphericus, Desor ; Clypeus a!tus, M‘Coy ; Ammonites Parkinsoni, Sow.;
and Terebratula spheroidalis, Sow.

The specimen I figured in the ‘Annals of Natural History’ as Hchinus serialis was said
to have been collected from Dundry Hill, but I find this was a mistake, as it turns out to

FROM THE GREAT OOLITE. 213

be a Dorsetshire fossil. I have never seen S¢. d2granularis in the Inferior Oolite of
Gloucestershire. In this county it is represented by S¢. intermedius.

The only authentic foreign locality that I am acquainted with is Croisilles, Calvados,
where it occurs in a brown ferruginous Inferior Oolite, containing numerous large grains
of the hydrate of iron, the “calc. a polypiers de Croisilles,’ Michelin.

History.—First figured in my ‘Memoir on the Cidaride of the Oolites’ as Hehinus
serialis, afterwards by Professor Forbes in the fifth decade, pl. 4, fig. 6, of the ‘Memoirs
of the Geological Survey ;’ where it was well described by Mr. Salter as Hehinus perlatus,
var. Horbesz.

B. Species from the Great Oolite—11° Htage, Bathonien, VOrbigny.
StoMECHINUS MicrocrPHUS, Wright, nov. sp. Pl. XV, fig. 1 a, 3.

Test circular, hemispherical, with a flat base; ambulacral areas with four rows of
tubercles, diminishing to two on the upper surface; inter-ambulacral areas with ten rows
of tubercles at the equator, irregularly disposed on the plates, and a median depression in
the lme of the centro-suture; poriferous zones wide, the pores in oblique ranks of threes,
and between each file two small granules regularly disposed.

Dimensions.— Height, six tenths of an mch ; transverse diameter, nearly one inch.

Description.—TVhe modern generic divisions of the family Ecutn1p often repose upon
characters which undergo many phases of development in the different species; and thus
it sometimes happens, as in the urchin now under consideration, some of the species
approach, in their ensemble, nearer to aberrant forms of an allied genus than to the one to
which they are referred.

This form certainly very much resembles a large Pol/ycyphus Normannus, Desor ;
although the state of conservation of the test, and the concealment of the base by
adherent rock, prevents that amount of examination so necessary for a critical diagnosis ;
still, however, the specimen exhibits such a group of characters, that I have placed it in
the genus Stomechinus for the following reasons: Ist, The size of the body; 2d, the
thickness of the test; 3d, the irregular arrangement of the tubercles on the inter-ambu-
lacral plates ; and 4th, the absence of a median depression in the inter-ambulacra.

The ambulacral areas (fig. 1 4) have four rows of tubercles at the equator, two marginal
rows placed on the extreme borders of the area, and two inner rows near the sutural line ;
the tubercles all alternate with each other (fig. 14), and the two inner rows disappear at
the upper surface.

214 STOMECHINUS.

The poriferous zones are wide; the pairs of pores are disposed in oblique ranks of
threes, rather widely asunder (fig. 1 4), and between each rank two small tubercles
are developed, which separate them from each other throughout the zones (fig. 1 4),
so that there is only one trigeminal rank of pores opposite each large inter-ambulacral
plate.

The inter-ambulacral segments are twice the width of the ambulacral; the centro-
suture is very distinctly marked, but there is no median depression, and the division of
the test into fifteen lobes, so characteristic of Po/ycyphus, is not seen in this form ; each
of the large plates in general supports four or five tubercles, which are rather irregularly
disposed on its surface (fig. 1 4); they have narrow, ring-like areolas around their base,
encircled by rows of small granules (fig. 1), invisible to the naked eye, and only
seen with a lens; the inter-ambulacra have therefore ten rows of tubercles at the equator ;
the third tubercle from the poriferous zones represents the principal row, which is con-
tinuous from the base to the disc; but the other lateral rows disappear at different points
between the circumference and the vertex.

The apical disc is unfortunately absent, and the base is adherent to a hard shelly
fragment of the Great Oolite limestone, which cannot be removed without, at the same
time, detaching the shell. In this remarkable formation, the Oolitic grains are mdented
into the plates of the test of the Echinodermata, as well as into the shells of the Mollusca ;
and unless the specimen separates readily from the matrix, it is almost hopeless to expect
to remove it without so much injury to the sculpture as will render its determination doubt-
ful, or even impossible. For this reason I have been unable to expose the base of this
beautiful rare form.

Affinities and differences.—Yhe nearest affinities of this species is with Polycyphus
Normannus, Desor; but it has a much thicker test, the inter-ambulacral tubercles are
proportionately smaller and more irregularly disposed, and they have circles of granules
around their areolas; the segments are not divided into lobes by median depressions ;
the poriferous zones are wide and only slightly depressed, and the trigeminal ranks of pores
are separated by small tubercles: all these diagnostic characters show how distinct
Stomechinus microcyphus is from Polycyphus Normannus, when a critical comparison is
made between these two urchins, which are often found in the same bed. I know of no
other form for which our species could be mistaken.

Locality and Stratigraphical position.—Yhis beautiful urchin is one of the many
exquisite fossils collected by my friend Mr. Lycett, from the Great Oolite of Minchin-
hampton Common. It occurs in the shelly beds of limestone at the large quarry, and
is the only specimen found by him, after many years’ diligent search, in his favorite
localities.

I have one small specimen of the same urchin, collected from the Great Oolite of

FROM THE CORAL RAG. 215

Ranville, Calvados, by M. Tesson, in which the apical disc is preserved. It is small and
prominent; the genital plates are nearly equal-sized, the right anterior plate is the
largest, and the spongy madreporiform body occupies all the surface of that plate; the
oculars are small, and deeply indented where they receive the apex of the ambulacra; the
genital holes are perforated about the outer third of the plates; the vent is oblong, and its
long diameter lies obliquely across the test. It is doubtless a rare urchin in France, as
none of the systematic authors make mention of it; or it may be that it has hitherto been
confounded with Polycyphus Normannus.

C. Species from the Coral Rag—14° Etage Corallien, @ Orbigny.

SroMECHINUS GrRAtTUS, Agassiz. Pl. XIV, fig. 4 a, 4, ¢, d, e.

ECHINUS GYRATUS. Agassiz, Echinoderm. Fossiles de la Suisse, part i, p. 87, pl. 23,

figs. 34—46.

— PETALLATUS. M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. ii, p. 409.

— GYRATUS. Agassiz and Desor, Catalogue raisonné des Hchinides, Annales des
Sciences Naturelles, 3"° série, tom. vi, p. 366.

— GYRATUS. Wright, Annals and Magazine of Natural History, 2d series»
vol. ix, p. 85.

— — Forbes in Morris’s Catalogue of British Fossils, 2d edit., p. 79.
— — Salter, Memoirs of the Geological Survey, Decade V. Notes on
Echinus, p. 8.
SroMECcHINUS GyRATUS. Desor, Synopsis des Echinides Fossiles, p. 126.

Test hemispherical, more or less elevated, inflated at the sides, round at the
circumference ; sides divided by depressions into fifteen unequal, slightly convex lobes ;
ambulacral areas half the width of the inter-ambulacral, with two complete rows of
marginal tubercles extending from the peristome to the disc, and two imcomplete rows of
central tubercles occupying two thirds of the sides; inter-ambulacral areas divided into
lobes by naked median depressions, which extend from the disc to the circumference ;
each lobe has one complete central row, and four incomplete lateral rows of secondary
tubercles ; apical disc central; vent small; mouth opening wide; peristome pentagonal.

Dimensions.—Height, one inch; transverse diameter one inch and four tenths.
Description—This beautiful urchin was figured, with details, by M. Agassiz, in his

‘Kchinodermes Fossiles de la Suisse ;’ its specific characters are so well marked that it can
scarcely be mistaken for any other species. ‘he test is hemispherical, more or less

216 STOMECHINUS.

elevated, and very regularly formed ; its surface is divided into fifteen nearly equal-sized
lobes grouped in five divisions, with three lobes in each, of which the ambulacra form the
centre, and the half of the adjoiming inter-ambulacra the two lateral lobes (fig. 4 a).

The distinctive character of this species consists in the wide, naked median depression
in the centre of the inter-ambulacral areas, which extends from the circumference to the
apical disc, and is throughout entirely destitute of granules or any other sculpture
(fig. 4); near the circumference, however, small tubercles occupy the space, and at this
point there are twelve tubercles, in a horizontal row, in a single inter-ambulacral area ; each
area is thus divided into two convex lobes by a median sulcus; in each lobe there is one
complete principal row of twenty-five tubercles, which extends from the peristome to the
disc, and two incomplete rows on each side of the principal row, with from twelve to
eighteen tubercles in each, which disappear on the sides; besides these at the widest part
of the area, a few small additional tubercles are introduced (fig. 4 c,d); the bosses are
small, and closely surrounded by circles of granules (fig. 4d); the tubercles are large and
prominent, and nearly all of the same size, which gives the surface of this urchin very
much the appearance of a large Polycyphus.

The ambulacral areas are nearly half as wide as the inter-ambulacral; they are
furnished with two complete rows of tubercles disposed on the margins of the area, and
two incomplete rows which occupy the central parts of the sides (fig. 42); the tubercles
have small bosses, around which granules are disposed in circles, and similar moniliform
granular rings surround the larger tubercles of the incomplete rows (fig. 4d).

The tubercles of both areas are large, prominent, and highly polished; those at the
base are a little larger than the tubercles on the sides; and it may be said of this species in
general that the test is uniformly very granular, and forms a remarkable contrast to that of
Stomechinus bigranularis (fig. 3 a).

The poriferous zones are narrow, the trigeminal ranks form angles of about 65°, which
become nearly sub-parallel in the upper part of the zone and at the base (fig. 4 4, c); two
small granules are dotted between each file of pores.

The apical disc is small and central (fig. 4a); the genital plates are nearly equal-sized,
with the exception of the right antero-lateral, which 1s the largest, and supports a fine
spongy madreporiform body (fig. 4); a series of granules on the plates form a circle
around the vent, which is of a moderate size. ‘lhe ocular plates are small, pentagonal
pieces, projecting from between the angles of the genitals; there are two holes in each
plate, with a transverse slit between (fig. 4e). The oviductal holes are conspicuous, and
perforated near the outer third of the plate.

The mouth opening is very large, nearly one half the diameter of the test (fig. 4 4); the
peristome is pentagonal, with two wide, obtuse notches at each angle, and a small, lip-like
lobe between; the ambulacral lobes are four times as broad as the inter-ambulacral, and
form the sides of the pentagon.

FROM THE CORAL RAG, 21

™~

Affinities and differences.—M. Desor, by mistake, has placed Stomechinus gyratus as a
synonym of Stomechinus germinans, and described the true Stomechinus germinans as a
new species under the name Stomechinus sub-conoideus, a confusion which has doubtless
arisen from the stratigraphical error already pointed out in the history of S#. germinans.
The following characters will show how entirely distinct S¢. gyratus is from the three
closely allied forms of the Inferior Oolite. It differs from S¥. germinans in having the
naked median sulcus wider and deeper, and extending further down the sides ; in having
four rows of equal-sized tubercles in the ambulacra, whilst Sé. germinans has only two.
The secondary tubercles of the inter-ambulacral areas are as large as the principal row,
and there is no miliary zone in this species; whereas, in Stomechinus germinans,
tntermedius, and bigranularis, the miliary zone is a very wide granular space. The
tubercles are likewise larger and nearly of the same size in both areas. I have been able to
examine Lchinus petallatus, M‘Coy, through the extreme kindness of Professor Sedgwick,
and compared it with the urchin I have figured; I can, therefore, state that it is an un-
questionable specimen of Hchinus gyratus, Agass., and not in any way a distinct form, as

Professor M‘Coy supposed.

Locality and Stratgraphical position—Stomechinus gyratus is rarely found in the Clay
beds of the Coral Rag, near Calne, Wilts; I am not aware that it has been collected in
any other locality in England. Its foreign locality is likewise limited to the “terrain a
Chailles” or Corallian stage of Besancon. I have a specimen from the Coral Rag of the
department of Haute Saone, France, kindly sent me by M. Michelin.

History.—First described by M. Agassiz in his ‘ Echinodermes Fossiles de la Suisse,’
where it is beautifully and accurately figured. The English form was afterwards described
by M‘Coy as ichinus petallatus. It was first described in detail in my ‘ Memoir on the
Cidaridee of the Oolites,’ and its distinction from our other Oolitic Echinidee was therein
indicated. It is probable, that Parkinson’s figure, in vol. 3 of his ‘Organic Remains,
described as an ‘ Hchinite from France,’ refers to this species.

SromEcntNus nubus, Wright, nov. sp. Pl. XV, fig. 2 a, 6, ¢, d, e.

Test circular, conoidal; ambulacra flat, with two regular marginal rows of tubercles,
twenty-four in each row, and two inner rows which occupy the middle half of the area ;
poriferous zones wide ; pores oblique; two small granules between each trigeminal rank ;
inter-ambulacra with eighteen plates in each column; equatorial plates with four or five

218 STOMECHINUS.

tubercles disposed irregularly on the surface on each plate, the number diminishing on the
upper surface ; tubercles surrounded by small, depressed, ring-like areolas, scarcely any
granules on the surface of the plates; apical disc small, genital plates narrow, ocular
plates prominent, with transverse eye-holes ; base flat, inter-ambulacra forming convex lobes
around the peristome.

Dimensions.—Height, seven tenths of an inch; transverse diameter nine tenths of an
inch.

Description—This small conoidal Hchinite in many respects resembles Sfomechinus
gyratus, Agass., and might at first sight be supposed to be a mere variety of that form,
but a closer examination proves it to be distinct ; the test 1s circular and elevated, the sides
rising suddenly from the basal angle; the ambulacral areas are flat, having two rows of
tubercles regularly arranged on their margins, about twenty-four in each row, with two
irregular internal rows, which occupy about the middle half of the area; the tubercles are
all nearly of the same size; they have narrow, sunken areolas around their base, but
scarcely any granules on the surface of the plates (fig. 2d).

The poriferous zones are wide, the trigeminal ranks form angles of 40° to 50°; between
each rank there are two granules, and there are three ranks opposite two tubercular plates ;
as there are eighteen plates in each column, there are therefore about twenty-seven trige-
minal ranks in each poriferous zone.

The inter-ambulacral areas are rather more thafi twice the width of the ambulacral,
each column contains about eighteen plates, and on each plate, at the widest part of the
area, there are from four to five tubercles, so irregularly disposed that the arrangement is
different on every plate (fig. 2 d); the tubercles are all about the same size, they are sur-
rounded by narrow, sunken areolas; a few smaller tubercles are scattered among them,
but there are no circles of granules around their base, which gives the surface of the
plates a naked appearance; there is no depression in the middle of the areas, and the
region of the centro-suture between the five uppermost pairs of plates is naked but not
depressed ; the areas become convex and prominent below.

The apical disc is small (fig. 2 a); the genital plates are narrow, and the anterior
larger than the posterior pair; the spongy madreporiform body occupies the surface of the
right anterior plate (fig. 2 e) ; the ocular plates are small, but prominent, and the eye-holes
form transverse slits on their sides; the vent is oblong (fig. 2 ¢), and around its margin
there are three parts of a circle of granules; the oviductal holes are large, and perforated
near the apex of the plates.

The base is much covered with adhering matrix (fig. 2 4), so that the form of the
mouth opening is nearly concealed; the tubercles are all much larger in this region, and
the wide depressed poriferous zones, and convex inter-ambulacral lobes, impart a lobed
appearance to the circumference of the mouth.

FROM THE CORAL RAG. 219

Affinities and differences.—This species most nearly resembles Stomechinus gyratus, but
is distinguished from it by the absence of the naked median depressions in the iuter-
ambulacral areas, which gives such a remarkable lobed character to the surface of its test ;
by the absence of the circles of granulations around the base of the tubercles; and the
naked appearance which the surface of the plates presents, in consequence of the almost
total absence of this granular ornamentation, and which is expressed by its specific
name nudus.

Locality and Stratigraphical position.—This Wchinite was collected in Wiltshire, but
[have not been able to ascertain the correct locality ; it appears to have been obtained from
the Coral Rag, although this is not certain.

29

we
we
=)

NOTES

On Forrign JURASSIC SPECIES OF tHE GENUS SIT'OMECHINUS, nearty aLuieD To

Bririsu FORMS, BUT WHICH HAVE NOT BEEN FOUND IN THE Eneuiso Oouitss.

STOMECHINUS MULTIGRANULARIS, Cofteau. Syn. Lehinus multigranularis, Cotteau.
Etudes sur les Hchinides Fossiles, pl. 7, figs. 6—8.

Test conoidal, with inflated sides, and a sub-pentagonal circumference; ambulacra
narrow and prominent, with four rows of tubercles; inter-ambulacra more than three times
as wide, with a naked median depression in the upper part of the area, and from eight to
ten rows of tubercles, irregularly disposed, in the widest part, diminishing to two rows
above; tubercles nearly all of the same size, except at the base, where they are
larger; intermediate space filled with fine granules. Apical disc moderately large ;
genital plates pentagonal, with a granular surface; vent sub-circular; base flat; mouth
opening very large, half the width of the test; peristome decagonal, with ten wide, obtuse
notches, and small inter-ambulacral Jobes between.

Dimensions.—Height, one inch and seven twentieths; transverse diameter, one inch
and three quarters.

Formation.—Bathonien, Great Oolite, of Grimaux, Yonne: very rare.

Collections. —M. Rathier ; a plaster mould in my cabinet.

Svomecninus Vacueyt, Cotteau. Syn. Hehinus Vacheyi, Cotteau. Etudes sur les
Hchinides Fossiles, pl. 3, figs. 12—16.

Test small, depressed, and pentagonal; ambulacra with two rows of tubercles ; inter-
ambulacra with two rows of primary tubercles, and a few scattered secondary tubercles ;
mouth opening large; peristome with small notches.

FOREIGN JURASSIC STOMECHINI. 221

Dimensions.—Height, three tenths of an inch; transverse diameter, six tenths of an

inch.

Formation.—Bathonien, “‘ dans les couches calcaires du Forest-marble, de Montillot,
Yonne.” Cotteau.

Collection. —M. Cotteau, a single specimen.

STOMECHINUS POLYPORUS, Agassiz. Syn. Hehinus polyporus, Agassiz. Catalogue syst.,
p. 12.

Test hemispherical, circular depressed; ambulacra with four rows of tubercles; inter-
ambulacra with close-set tubercles at the base and circumference, which rapidly diminish
on the upper surface. It is distinguished from Stomechinus bigranularis by having four

rows of tubercles in the ambulacra.

Formation.—Bathonien de Ranville? Rare.

Collection —M. Michelin.

SromEcHiInus Cavumonti, Desor. Synopsis des Echinides Fossiles, p. 128.

Test sub-conoidal, inflated at the sides; ambulacra with four rows of tubercles, the
two internal rows short and less regular; inter-ambulacra with from eight to ten
rows of tubercles at the circumference, which diminish little in size at the upper surface ;
mouth opening very large. ‘This species is found to be one of the most characteristic of

the Bathonien stage.” Desor.

Formation.—* Marnes 2 Ostrea acuminata (Vesulien) de Herznach (Argovie).
Kellovien de Chatillon-sur-Seine.”

Collections. —“ Hébert, Mesch, Mus. Zurich. Assez abondante.”” Desor.

222 FOREIGN JURASSIC STOMECHINI.

SToMECHINUS APERTUS, Desor. Synopsis des Hchinides Fossiles, p. 127.

Test sub-conical, pentagonal; ambulacra with two rows of tubercles, a little less in
size, but more numerous than in the inter-ambulacra, which have six rows of tubercles at
the circumference; mouth opening very large. ‘‘This species was formerly confounded
with Hchinus eaxcavatus, Goldf., which has the ambulacral tubercles much smaller, and
set more close together than those of the inter-ambulacra, whilst in Stomechinus apertus their
difference in size is scarcely perceptible.” Desor.

Hormation.—Kellovien de marolles pres Mamers, Courgains, Nantua. Rare.

Collections. —M. Michelin, d’Orbigny, Paris Museum.

Sromncuinus Ropinaupinus, Cotteav. Syn. Echinus Robinaldinus, Cotteau. Etudes
sur les Echinides Fossiles, pl. 22, figs. 1—6.

Test sub-conoidal, inflated at the sides; circumference sub-circular ; ambulacra with
four regular rows of tubercles, identical with those of the mter-ambulacra ; poriferous zones
wide, trigeminal ranks very oblique; inter-ambulacra double the width of the ambulacra,
and covered throughout with equal-sized tubercles, regularly disposed in numerous series,
six tubercles on each plate; apical disc composed of equal-sized genital plates; vent large ;
mouth opening moderate in width, in the proportion of one to two and a half; peristome
decagonal, with wide, obtuse notches.

Dimensions.—Height, one inch and a half; transverse diameter, two inches and one
fifth.

formation.—“ Cette espéce caractérise les couches supérieures de |’étage Corallien et
n’a jamais été rencontrée dans le Coral-rag inferieur de Chatel-

Censoir et de Druyes.” Cotteau.

Collection.—M. Robineau-Desvoidy. Very rare; only three specimens known.

FOREIGN JURASSIC STOMECHINI. 223

SromEcninus Orpienyanvs, Cotteau. Syn. Echinus Orbignyanus, Cotteau. Etudes sur
les Echinides Fossiles, pl. 21, figs. 8—13.

‘Test hemispherical, depressed ; circumference circular; ambulacra with two marginal
rows of tubercles, and a naked zone between: inter-ambulacra with six rows of tubercles
at the equator, diminishing to two rows above; base concave; mouth opening wide, half
the diameter of the test; peristome pentagonal, deeply notched.

Dimensions.—Height, six tenths of an inch; transverse diameter, one inch and one
twentieth.

Formation.—* Caleaires marneux et lithographiques de Commissey Corallien étage.”
Cotteau.

Collection.—M. Rathier. Very rare.

STOMECHINUS ExcavaTUS, Goldfuss. Syn. Hehinus excavatus, Goldfuss. Petrefacta.
Germanie, tabl. 40, fig. 12.

Test hemispherical, depressed, sub-pentagonal; ambulacra with two marginal rows of
close-set tubercles, smaller than those of the other areas; inter-ambulacra with two rows
of primary tubercles on the sides, and four other secondary rows at the base.

#
Dimensions.—Height, eleven twentieths of an inch; transverse diameter, one inch.

Formation Findet sich in den obersten Schichten des Jurakalkes bei Regensburg
und in Schwaben.” Goldfuss.

Collection.—Munich Museum. Very rare.

STOMECHINUS SERIALIS, Agassiz. Syn. Echinus serialis, Agassiz. Echinod. Foss. Suisse,
II, tabl. 22, figs. 10—12.

Test circular, much depressed ; ambulacra with two regular rows of tubercles ; pori-
ferous zones very narrow; inter-ambulacra with six rows of tubercles at the circumference,
diminishing to two rows above; mouth opening very large; peristome decagonal, with
obtuse notches.

224 FOREIGN JURASSIC STOMECHINI.

Dimensions.—Height, four tenths of an inch; transverse diameter, three quarters of
an inch.

Formation.—< Corallien infér. (Terrain a Chailles) du Fringeli (Jura Soleurois).” Desor.

Collection.—M. Gressly. Very rare.

STOMECHINUS LINEATUS, Goldfuss. Syn. chinus lineatus, Goldfuss. Petrefacta
Germanie, tabl. 40, fig. 11.

Test hemispherical, depressed, circular, or slightly sub-pentagonal ; ambulacra with
two rows of tubercles on the margins, and two small rudimentary rows internal to them ;
inter-ambulacra with six rows of tubercles at the circumference, diminishing to two rows
above; tubercles of both areas prominent, and nearly of the same size; bosses encircled
with granules ; the general surface is very tuberculous.

Dimensions —Height, one inch; transverse diameter, one inch and three quarters.

Formation.—From the Coral Rag of Regensburg and Basel. The specimen kindly sent
me by M. Michelin is from the Coral Rag of Niederdoff, Canton de Bale.

Collections.—Museums of Tiibingen, Besancon, Munich, collection of M. Michelin.
Royal College of Surgeons (Hunterian Collection), my cabinet.

SToMECHINUS PERLATUS, Desmarest. Syn. Echinus perlatus, Agassiz. Hchinoderm.
Foss. Suisse, part u, pl. 22, figs. 13—1L5.
Knorr. Petrefact., i, tab. u, figs. 1, 2.

Test conoidal, sub-circular, or sub-pentagonal ; the transverse and bucco-anal diameters
are sometimes nearly equal; ambulacra with two complete rows of tubercles on the mar-
gins, two incomplete rows within, and numerous small granules encircling their bosses ;
inter-ambulacra with ten rows of small tubercles at the circumference, two rows of which
are larger, and extend from the peristome to the disc, the others disappear on the upper
surface ; the bosses of all the tubercles are surrounded by fine granules, which imparts a
highly sculptured appearance to the test of this species; poriferous zones narrow, trigemi-
nal ranks, form angles of 50° to 55°; apical disc moderate, ovarial plates large; mouth

FOREIGN JURASSIC STOMECHINI. 225

opening very large, half the diameter of the test; peristome pentagonal, the ten notches
wide and obtuse, with small lobes between.

Dimensions.—Specimen figured by M. Agassiz: height, one inch and three quarters ;
transverse diameter, two inches and four tenths.
Specimen in my cabinet: height, one inch; transverse diameter, one
inch and nine tenths.

Formation —Corallien infér. (Terrain & Chailles) de la Combe d’Echert (du Val de
Moutiers), de Salins. Corallien étage Commercey (Meurthe), Chatel-
Censoir, et Druyes (Yonne).

Collections —Museums Neuchatel, Bale, Porrentruy. Collection of M. Michelin.
British Museum, my cabinet.

STOMECHINUS SEMIPLACENTA, Desor. Cotteau, Etudes sur les Hchinides Foss.,
pl. 45, fig. 5.

Test sub-circular, sub-inflated above, concave below; ambulacra with four rows of
tubercles ; inter-ambulacra with ten rows of tubercles at the circumference, irregularly
disposed, diminishing on the upper surface; tubercles of both areas nearly equal-sized,
and each surrounded by circles of granules; mouth opening very large; peristome
decagonal, notches very wide and deep.

Dimensions.—Height, nine tenths of an inch; transverse diameter, one inch and seven
tenths.

Formation.—“ Kimméridge étage des environs de Chablis et Havre.” Cotteau.

Collections —MM. Rathier, Royer.

226

Family 5—SALENIAD A.

This natural family nearly corresponds to the Salénies of MM. Agassiz and Desor,
and is distinguished from other families of the Ecutnorpna EnDocyctica by the peculiar
structure and great development of the apical disc, which, besides the five genital and
five ocular plates, has an additional or sur-anal plate, developed in the centre of the disc,
immediately before the anal opening; this plate is sometimes single, or more frequently
is composed of from three to eight separate elements.

The test is thin, and in general small, spheroidal, hemispherical, or depressed: the
ambulacral areas are always narrow, straight, or flexuous, with two rows of small
tubercles which alternate with each other on the margins of the area.

The poriferous zones are narrow, the pores unigeminal, except near the peristome,
where they fall ito oblique ranks of threes.

The inter-ambulacral areas are wide, with two rows of primary tubercles, which have
large bosses with crenulated summits; in one section the tubercles are perforated, in the
other they are imperforated.

The mouth opening differs im size in the different genera; the peristome is more or
less decagonal, and is sometimes deeply notched, or only feebly indented. The jaws
are known in one genus, in which they resemble those of Hemicidarvs.

The spines of one section (the Acrosalenia) are only known; in this genus, the stems
are long, slender, angular, or flattened, and the surface, although apparently smooth, is
covered with very fine longitudinal limes.

From a misconception of the true relative position of the elements of the apical disc,
in this family, much confusion exists in the works of different authors in the descrip-
tion of this part of the test. ‘The great difficulty in the study of this group,” says
M. Desor,* ‘is to find the place of the madreporiform body; we are consequently em-
barrassed when we attempt to assign the lateral parts to the longitudinal axis of these
animals ; unless we admit that the sur-anal replaces the madreporiform body; but this
would be contrary to all analogy, because in all the other Cidarides, the madreporiform
body is an integral part of one of the genital plates. M. Agassiz had got rid of the
difficulty by means of an hypothesis, by admitting that the sur-anal plate is invariably
placed in the plane of the animal, that it therefore could only be anterior or posterior ;
hence his two divisions in the genus Sa/enta,—the first with a sur-anal plate posterior, and,
consequently, with the périprocte excentral and before; the second with the sur-anal
plate anterior, and, consequently, with the périprocte excentral and behind.”’}

* «Synopsis des Echinides Fossiles,’ p. 138.
+ For further details on this subject, M. Agassiz’s ‘Monographies d’Echinodermes, premiére Mono-
graphie des Salenies,’ may be consulted.

SALENIAD A. 227

Professor Johannes Miiller assigns the left posterior genital plate as the bearer of the
madreporiform body in Salenia personata. “ Dies wird auch durch die Salenien bestitigt,
wo die Liingsachse durch die plaque suranale vor dem After bestimmt wird. An einem
im mineralogischen Museum aufbewahrten ausgezeichnet schénen Exemplar der Sa/enia
personata, Ag., mit vorderem After, Taf. 1, Fig. 9, ist die linke hintere Genitalplatte
pords und Madreporenplatte.”*

I have selected fine specimens of Hyposalenia Wrightii, Desor, from the Lower Green
Sand, Salenia petalifera, Desmarest, from the Upper Green Sand, and Salenia Austeni,
Forbes, from the Lower Chalk, in all of which the madreporiform body occupies the surface
of the right anterior genital plate, as in the Ciparip#, Humicrparip#, DiapEMADA, and
Ecuinip&. ‘The sur-anal plate is central, and the anal opening posterior, and inclined
to the right side. In fact, the madreporiform body and sand canal, whatever their true
functions may be, have the same position in all the Hchinoidea, recent and fossil, which I
have examined ; and probably the same in all the Echinodermata. Professor Miiller’s mis-
take, therefore, may have arisen from his placing the Sa/enza in a false position before him.

The study of the apical disc in the Acrosalenia reveals the true relation of its elements
to each other, and proves that the sur-anal plate has nothing in common with the spongy
madreporiform body which occupies the surface of the right anterior genital plate
(Pl. XV, fig. 4 a, 7). I had the good fortune to make this discovery some yearst ago,
when figuring and describing Acrosalenia hemicidaroides, which urchin has furnished
the key to the true relation of the bilateral parts to the longitudinal axis of the SaLunraDA&.
On this point M. Desor observes :

“Nous devons en outre 4 M. Wright une autre découverte plus importante, celle du
corps madréporiforme, qui fait partie intégrante de l'une des plaques génitales comme dans
les autres Cidarides. Or comme nous savons maintenant que cette plaque a une posi-
tion fixe dans tous les oursins, nous sommes par la méme en mesure de déterminer l’avant
et l’arriére de ces animaux ; et puisque les plaques sur-anales sont situées en arriére de
cette plaque, il s’ensuit que le périprocte se trouve réellement refoulé en arriére. [I ne
peut dés-lors plus étre question d’Acrosalénies a périprocte eccentrique en avant, comme
on supposait que c’était le cas de l Acrosalenia tuberculosa,” &c.

“Tl w’arrive que trop souvent que le disque apicial manque, et dans ce cas, il est trés-
difficile de distinguer les Acrosalénies du genre Hemipedina décrit ci-dessus. Cependant,
comme par suite du refoulement du périprocte en arriére la plaque géenitale impaire ou
postérieure gagne plus que les autres sur le test, on peut encore, d’apres M. Wright, re-
connaitre la place de cette plaque méme dans les individus dépourvus d’appareil
apicial.”

* Joh. Miiller, ‘Uber den Bau der Echinodermen,’ Daa
+ Wright, ‘Annals and Magazine of Natural History,’ 2d series, vol. vii, p. 261.
{ ‘Synopsis des Echinides Fossiles,’ p. 140.

30

228

FaMILY.

SALENIADA.

A.

SECTION

Section B.

SALENIAD A‘.

A TABLE SHOWING THE CLASSIFICATION oF THE SALENIADA.

SECTIONS.

Tubercles

Tubercles imperforate.
Apical disc large, shield-like,

perforated.

Apical disc

and prominent.

small.

DraGnosts.

Inter-ambulacral tubercles large; apical
disc small and not prominent ; sur-anal
plate composed of one or many pieces ;
vent posterior and excentral.

Inter-ambulacral tubercles moderate ; api-
cal disc large and prominent; genital
plates in the form of elongated lobes ;
sur-anal plate single ; vent posterior and
slightly excentral.

Inter-ambulacral tubercles large, few in
number ; apical disc large, and forming
a regular pentagon, with elevated angu-
lar carinze independent of the sutures ;
sur-anal plate angular; vent large, ex-
central, oblong, and posterior.

GENERA.

ACROSALENIA, Agassiz.

GontopHoRus, Agassic.

: PeLTastEs, Agassiz.
|

Inter-ambulacral tubercles large; apical )

disc large, prominent, and shield-like ;
border undulated, with punctuations or
sculpture in the lines of the sutures: sur-
anal plate single, central; vent excentral,
posterior, and inclined to the right side.

HyposaLenia, Desor.

Inter-ambulacral tubercles very large; -

apical disc large and very solid, with an
undulated circumference; surface of the
large plates ornamented with punctua-
tions, or sculptured figures along the
line of the sutures ; sur-anal plate single ;
vent excentral, and directed towards the
right side.

SALENIA, Gray.

229

Genus—ACROSALENIA. Agassiz, 1840.

This genus is composed of small or moderate-sized urchins with a thin spheroidal,
hemispherical, or depressed test.

The ambulacral areas are narrow, straight, or slightly undulated, with two rows of
small crenulated and perforated tubercles on their margins, which diminish gradually in size
from the base to the apex.

The inter-ambulacral areas are wide, having two rows of primary perforated tubercles,
raised on large prominent bosses with crenulated summits.

The apical disc is proportionally smaller than in other genera of the SaLentapa@, and
forms no prominence on the surface of the test ; the sur-anal plate, sometimes single, is in
general composed of many separate pieces placed before the anal opening, which renders
it excentral and displaces the vent backwards; the anterior pair of genital plates are
larger than the posterior pair, and the single plate is small and crescentic; the spongy
madreporiform body occupies the right anterior genital plate.

The mouth opening is large, often one half the diameter of the test; the peristome is
decagonal, with ten wide notches which have the margin reflected over their border.

The primary spines are long, circular, flattened, or angular; and they are sometimes
twice the length of the diameter of the body; although apparently smooth, still with a
lens, their surface is seen to be covered with fine longitudinal lines. The secondary
spines are short, regular, round, and striated.

The Acrosalenias are found in the different stages of the Oolitic rocks from the Lias to
the Portland, but they are most numerous in the lower division of the Oolites; recent
researches have shown that this genus contains a much larger number of species than was
originally supposed, when many of them were erroneously referred to other genera, in
consequence of the apical disc being absent in a very great number of specimens.

When the apical disc is absent, an Acrosalenia may be easily mistaken for a Hemz-
cidaris, but the aperture in Acrosalenia is always larger, and one of its angles projects
further mto the single inter-ambulacrum than into the others; the posterior pair of am-
bulacra are more curved backwards than the anterior pair, and the single anterior area is
always straight ; it requires a considerable practice of the eye and the handling of many
specimens, before we can determine accurately by these characters ; but practice has convinced
me of their value, and I have now no difficulty in distinguishing an Acrosalenia, whether
the disc be present or not. ‘The absence of true semi-tubercles from the base of the
ambulacral areas, likewise assists in the diagnosis.

230 ACROSALENTIA.

A. Species from the nas.
ACROSALENIA MINUTA, Buckman. PI. XV, fig. 3 a, 6,¢; Pl. XVIL, fig. 2 a, 0, ¢, d, e.

ECHINUS MINUTUS. Buckman, in Murchison’s Geology of Cheltenham, 2d ed., p. 95.
ACROSALENIA CRINIFERA. Wright, Annals and Magazine of Natural History, 2d series,
vol. xii, p. 168, pl. 12, fig. 1.

_- —_— Forbes, in Morris’s Catalogue of British Fossils, 2d edition.
Additional species of Echinodermata.

— MINUTA. Oppel, die Jura Formation Englands, Frankreichs, und des
stidwestlichen Deutschlands, p. 110.

Test circular, depressed ; ambulacral areas very narrow, with two rows of microscopic
tubercles placed at some distance apart on the sides of the area, those on the right side
alternating with those of the left; inter-ambulacral areas with two rows of primary
tubercles, from nine to ten in each row, so disposed that the test appears, from the
narrowness of the ambulacra, to possess only ten rows of tubercles, nearly equidistant from
each other; spines long, numerous, and hair-like.

Dimensions.—Height, three twentieths of an inch; transverse diameter, six twentieths
of an inch.

Description.—This beautiful little urchin has been long known to our local geologists,
as it was obtained in great numbers when cutting through the Oxynotus bed of the Lower
Lias in the formation of the Birmingham and Bristol Railway; it has often been a
palzontological puzzle, for although a few specimens have been found in a tolerable state
of preservation, still, for the most part, the test is so much injured by pyrites, that it
requires a good lens, and much patient study, to make out the details of its structure. I
lately found a very good specimen in the Oxynotus shales near Lansdown, which forms the
subject of fig. 2, Pl. XVII, and is the most perfect example I have seen. In my ‘ Memoir on
the Lias Echinodermata,’ I figured and described this species as Acrosalenia crinifera,
Quenst., but my friend Dr. Oppel, of Stuttgart, having kindly sent me the type of
Quenstedt’s species, I am satisfied, from the comparative shortness of the spines of our
urchin, that it is distinct from that form, and have, therefore, restored its original specific
name, minuta.

The test is nearly circular, and is more or less depressed; the ambulacral areas are
extremely narrow (Pl. XVII, fig. 2 @), with two rows of minute marginal tubercles, not much
larger than the common granulation of the test; these tubercles are placed in each row at
some distance apart (fig. 2¢), and the tubercles of the one side alternate with those of
the opposite (fig. 2 4); between these two rows of tubercles there is a narrow, zigzag line
of granulations ; the tubercles are very uniform in size throughout the area, but to see

FROM THE LIAS. 231

them satisfactorily it is necessary to examine the test with a microscope under an inch
object-glass.

The poriferous zones are extremely narrow; the pores are small, there being four pairs
opposite each tubercular plate; the septa are slightly elevated, and form a microscopic
moniliform line between the pores (fig. 2 e).

The inter-ambulacral areas are wide (fig. 2 4, ¢), with two rows of primary tubercles,
from nine to ten in each row; they are situated near the zonal sides of the plates, and have
a wide miliary zone between them; the bosses have deeply crenulated summits, and the
tubercles are small and widely perforated ; well-defined areolas encircle the bosses (fig. 2 e),
which are confluent above and below; the miliary zone consists of an elevated band,
composed of from four to six rows of small, unequal-sized granules (fig. 2 e), which extend
from the peristome to the disc. When viewed with the naked eye, at the equator, this
tiny urchin appears to possess only ten rows of tubercles, nearly equidistant from each
other (fig. 2 a), but when examined with a microscope its true structure is seen; the
extreme narrowness of the ambulacral areas, with their close, alternate rows of microscopic
tubercles, and the width of the miliary zone, with its unequal-sized granules, alike
contribute to make the deception almost complete (fig. 2 4).

The opening for the disc is nearly one half the diameter of the test, but I have never
seen the trace of a plate in any specimen I have examined (fig. 2 ¢).

The mouth opening is small, about one third the diameter of the test, and lies in a
concave depression (fig. 2 4); the peristome is feebly notched, and the lobes are of unequal
size (fig. 2 6).

The most remarkable portions of the structure of this tiny fossil are the spines, which,
in some crushed specimens, are preserved iz si¢# between the laminz of the Lias shales ;
they are long, slender, and hair-like, with a well-developed head; on some slabs these
spines resemble so many fine bristles, laid down in all directions, upon the surtace of the
laminated Oxynotus shales; in one crushed test, four tenths of an inch in diameter, the
spines measured upwards of an inch in length.

Afinities and differences.—The smallness of the test, and the length and hair-like
character of the spines, are sufficient to distinguish Acrosalenia minuta from all other Lower
Lias urchins. In the shales of the Upper Lias, there is another small urchin with long,
hair-like spines; but I have never yet succeeded in obtaining a specimen in sufficient
preservation to enable me to institute a comparison between it and Acrosalenia minuta ;
the Upper Lias form reminds me very much of Cidarites crinifera, Quenstedt, from the
« Posidonienschiefer von Pliensbach bei Boll in Wiirtemberg,” a bed of the Upper Lias.

Locality and Stratigraphical position —Acrosalenia minuta was found in the laminated
Oxynotus shales of the Lower Lias at Lansdown, Cheltenham, and likewise at Gloucester,
whilst excavating the same bed to form a new dock. It was associated in both places with

232 ACROSALENTA.

Ammonites oaynotus, Quenstedt, and Ammonites raricostatus, Zieten; these Ammonites
characterise the horizon of this species in a very definite manner. I have lately received
the spines of this urchin, which were collected from the Lower Lias near Stratford-on-Avon.

Dr. Oppel states that Acrosalenia minuta is found in the Lower Lias of Wiirttemberg.
“Die flachgedriickten Korper mit den feimen Stacheln fiillen ee ganze Schichte in der
Region des Pentacrinus tuberculatus. Sie legen haufig verkiest in den bituminésen Schiefern
des untern Lias an der Steinlach bei Dusslingen, und wurden von meinem Freund
Dr. Rolle zuerst darin aufgefunden.””*

History.—First described by Professor Buckman, in the ‘ Geology of Cheltenham,’ as
Echinus minutus. Afterwards, in my ‘ Memoir on Lias Echinodermata,’ it was figured for
the first time, and described as Acrosalenia crinifera, Quenst.; a comparison of our species
with the German urchin has induced me to restore its original specific name. It has been
subsequently found by Dr. Rolle in the Tuderculatus bed at Steimlach.

B. Species from the Inferior Oolite—10° Btage Bajocien, D’Orbigny.
AcrosaLenta Lycerti, Wright. Plate XVI, fig. 1 a, 4, ¢, d, e, f.

AcrosaLenta Lycertir. Wright, Annals and Magazine of Natural History, 2d ser., vol. viii,
p. 263, pl. 11, fig. 2.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 70.
— — Desor, Synopsis des Kchinides Fossiles, p. 142.

Test hemispherical, much depressed on the upper surface, and flat at the base;
circumference circular or sub-pentagonal; ambulacral areas narrow, with two rows of
prominent tubercles on the margins ; inter-ambulacral areas wide, the two rows of tubercles
with very large, prominent bosses; miliary zone with two rows of granules at the equator,
and a naked median depression between the three upper pairs of tubercles; apical disc
small and prominent; sur-anal plate single; vent small. and transversely oblong.

Dimensions—Height, half an inch; transverse diameter one inch.

Description.—This urchin at first sight so much resembles a Hemicidaris that it
might readily be mistaken for one, m consequence of the size of the ambulacral, and the
prominence of the bosses of the inter-ambulacral tubercles; but a more careful study of
the test soon discloses its true generic character.

A transmutationist will doubtless find it a difficult matter to discover the progenitor of
this urchin ; it makes its appearance in the lowest beds of the Inferior Oolite, with all its
Acrosalenian characters so strongly developed, that it may be taken as a good type of the

* Dr, Oppel, die Jura Formation, p. 110.

FROM THE INFERIOR OOLITE. 233

genus. This is not the only example among fossil Echinodermata illustrative of the fact,
that the first created forms of new types of life are often the most characteristic of the
group they represent; the figure and description of the first species of every genus
contained in this Monograph is, in fact, a practical commentary on this great natural law.

The ambulacral areas are narrow, straight, and prominent; they have two rows of
small, well-developed tubercles, from twelve to fourteen in each row, disposed on the
margins of the areas, which gradually diminish in size from the base to the apex
(fig. 1 a, 6); a zigzag line of small granules descends down the centre, sending lateral
branches between every two tubercles; this granular network encircles three parts of the
areolas, and leaves them open only to the poriferous zones (fig. 1 Z); the tubercles at the
base of the area (fig. 1 4, e) are large, and remind us of the semi-tubercles in this region
in Hemicidaris.

The poriferous zones are narrow; the pores are unigeminal, except at the base, where
they fall mto oblique ranks of threes (fig. 1 e); there are eleven pairs of pores opposite
two large plates (fig. 1 @).

The inter-ambulacral areas are three times and a half as wide as the ambulacral; there
are eight tubercles im each row, which, at the circumference, are raised on very large
prominent bosses (fig. 1 a,c); one of these mamme, drawn in profile (fig. 17), shows its
conical form ; it is surrounded by a wide, oval areola (fig. 1 ¢), which is confluent with its
fellow above and below; the tubercles are large at the base, but suddenly diminish in size
in the upper part of the area; there are ten crenulations on the summits of the bosses,
and the tubercles are small in proportion to the magnitude of these eminences; the two
rows of tubercles are separated by a zigzag granular band, or miliary zone, in the centre
of the area (fig. 1 ¢), consisting of two rows of granules, and a few additional smaller ones
dotted here and there in the interspaces ; similar crescentic bands of granules separate the
areolas from the poriferous zones ; each plate, therefore (fig. 1d), has a semi-circular row
of granules, with a few granulets, on its central side, and a similar row on its zonal side,
whilst the upper and lower borders are destitute of sculpture. On the upper part of the
area the granules disappear, and leave a small, naked, median depression between the three
uppermost pairs of small tubercles (fig. 1 a).

The base is flat, or slightly concave (fig. 1 c); the mouth opening is large, one half the
diameter of the test; the peristome is decagonal, and divided by wide notches into
unequal-sized lobes, the ambulacral being one half larger than the inter-ambulacral lobes
(fig. 1 4), and its margin is folded over at the angles of the notches (fig. 1 ¢).

The small apical disc is very seldom preserved; fortunately I lately found one
specimen with most of the plates 2 situ (fig. 1 a), and another with the sur-anal plate,
which is single, or more probably composed of three plates soldered together; it is the
only specimen I have seen with this portion of the disc, the coarse character of the Pea-grit
in which they are found being unfavorable for the preservation of this fragile and complex
part of the shell.

234 ACROSALENTA.

Affinities and differences.—This species resembles Acrosalenia hemicidaroides, Wright,
but is distinguished from it by having the test more depressed, the ambulacral tubercles larger
and more prominent, the three upper pairs of the primary inter-ambulacral tubercles smaller,
with a naked median depression in the centre of the upper part of the miliary zone; the
apical disc is likewise smaller. The size and prominence of the ambulacral tubercles form
a distinctive character between <Acrosalenia Lycettii and Acrosalenia pustulata on the
one side, and Acrosalenia Wiltoni on the other, both of which have small and widely
spaced-out tubercles in the embulacral areas.

Locality and WStratigraphical position.—I\ have collected this urchin from the
lower ferruginous beds of the Inferior Oolite, the Pea grit, at Crickley, Leckhampton,
and Cooper’s Hills; from a sandy seam of the lower beds of the Inferior Oolite at
Stinchcombe ; and likewise from the lower beds of the Inferior Oolite at Brockhampton,
Cleeve, and Sudely Hills. It occurs likewise in the shelly beds of the Roe-stone at
Leckhampton, and has been catalogued in the Rev. P. B. Brodie’s paper* as Acrosalenia
Hloffmani, Romer. Although an abundant species, it is seldom found in good preservation,
the shell being always more or less crushed ; it is commonly associated with Pseudodiadema
depressum, Agass., which it somewhat resembles, but is easily distinguished from that
form by the disproportion between the size of the ambulacral and inter-ambulacral
tubercles.

History.—It was first figured and described in my ‘ Memoir on the Cidaride of the
Oolites,’ and is dedicated to my friend John Lycett, Hsq., one of the learned authors of the
‘Monograph on the Mollusca of the Great Oolite,’ which has already enriched the volumes
of the Palzeontographical Society.

C. Species from the Great Oolite, Bradford Clay, Forest Marble, and Cornbrash.—
11° Htage Bathonien, D’Orbigny.

ACROSALENIA HEMICIDAROIDES, Wright. Pl. XV, fig. 4 a, 6, ¢, d, e, f, 9, h, 1, m.

ACROSALENIA HEMICIDAROIDES. Wright, Annals and Magazine of Natural History, 2d ser.,
vol. vill, p. 161, pl. 11, fig. 1.
— — Forbes, Memoirs of the Geological Survey, Decade IV,
pl. 2.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d edit.,
p. 70.
= = Desor, Synopsis des chinides Fossiles, p. 144.

* «Quarterly Journal of the Geological Society,’ vol. vi, p. 247.

FROM THE GREAT OOLITE. 235

Test hemispherical, more or less depressed, sometimes elevated ; ambulacral areas
narrow, undulated, with two rows of small, perforated tubercles, fourteen to sixteen in
each row, which alternate on the borders of the area, and gradually diminish in size from
the base to the apex; inter-ambulacral areas with large prominent tubercles on the sides,
and small tubercles near the disc ; areolas sub-confluent ; miliary zone narrow, with two
rows of granules ; apical disc very large ; sur-anal plate composed of six elements; mouth
large, decagonal ; peristome deeply notched ; primary spines twice or more in length the
diameter of the test; stem sub-angular, tapering, or slightly gampressed extremity some-
times bifid or trifid.

Dimensions.—This species varies so much in size and figure, that I have selected four
specimens on account of their differences, the comparative dimensions of which are shown
in the following table :

Largest form. Elevated form. | Depressed form. | Common small form.
Acrosalenia hemicidaroides. Wright. i RRUTES. Tn Mace |(> MIS Pa Te
Inch. Inch. Inch. Inch.
Transverse diameter of test : 1+, 135 15 0-6,
Height of test . : : 0-5 035 0,5, 01
Diameter of mouth opening : 05 on 0F 02
Length of apical disc : : 0-%5 035 04 0+;

Description.—This is the most common and best preserved of all our fossil sea-urchins ;
it has long been known as a Cornbrash species, but was neither named, figured, nor
described, until I gave its history, with figures and details, in my ‘ Memoir on the Cidaridee
of the Oolites ;’ since then it has been figured and described by Professor Forbes in the
fourth Decade of the ‘ Memoirs of the Geological Survey ;’ and by M. Desor, in tabl. XX,
figs. 19 —23, of his valuable ‘Synopsis des Echinides Fossiles.’ This species exhibits much
variation in size and figure, but its diagnostic characters are preserved with remarkable
uniformity throughout these different phases of form and magnitude.

The test is sometimes elevated and globular, like a Hemicidaris; indeed, the large
forms, the dimensions of which are given in the first column of the table of measurements,
are commonly so named; the absence of semi-tubercles at the base of the ambulacra,
and the large size of the elongated discal opening, are the only characters by which they
can be distinguished from that genus. In the more common form (fig. 4 c), the body
is spheroidal and depressed on the upper surface; and, when the flattening is excessive, it
produces the depressed form of the third column.

‘he ambulacral areas are narrow and moderately prominent (fig. 4 a); they are
nearly of a uniform width, gradually expanding in the lower half, and tapering in

31

236 ACROSALENIA.

the upper; they exhibit a very slight undulating contour, and have two rows of small,
nearly equal-sized secondary tubercles, from sixteen to eighteen in each row (fig. 4 ¢) ; the
tubercles at the basal angle are the largest (fig. 4 4, e), and they imperceptibly diminish in
size from the circumference to the disc (fig. 4 a), they are all perforated and raised on
bosses, which have ten crenulations on their summits (fig. 4 7); the tubercles of each row
alternate, and in the centre of the area there are one or two rows of granules, which send
off small lateral branches to encircle the areolas (fig. 4 d, e).

The inter-ambulacral areas are nearly four times as wide as the ambulacral ; they consist
of two columns, each composed of seven or eight plates, each plate bearing a primary
tubercle (fig. 4 d) ; the two plates nearest the peristome are very small (fig. 4 4), the four on
the sides are very large (fig. 4 ¢), and the two near the disc are small (fig. 4 a); the
tubercles are elevated on very large bosses (fig. 4 7), which have ten or more deep
crenulations on their summits, the tubercles themselves are perforated; around the
base of the boss there is a wide, smooth areola; the plates are bordered by a single row
of granules (fig. 4 d@), which, however, is sometimes absent from the upper and lower
borders, the areolas then being confluent ; the miliary zone is narrow, and is formed of two
rows of granules, with the intermediate angles having a few smaller additional granules
introduced ; the areolas are separated from the poriferous zones by a row of granules on the
zonal side of the plates (fig. 4 7).

The poriferous zones are narrow, the pores unigeminal throughout, except at
the base, where they fall to triple oblique rows; the septa form small elevations
on the surface, and a beaded line thereby passes down the zone between the pores
forming a pair (fig. 4 @), and there are nine or ten pairs of pores opposite each tubercular
plate.

The apical disc is often admirably preserved in this beautiful urchin ; the study of its
curious structure first enabled me to correct M. Agassiz’s erroneous supposition, that
the genital plate, which carries the madreporiform body, is the single plate, and repre-
sents the posterior side of the animal, instead of the right antero-lateral plate which
occupies the same relative position in all the Hou1no1pzEa.

The disc is one third the width of the test, and in consequence of the projection of the
genital plates has a pentagonal form; it is slightly convex and prominent, the anterior
and posterior pair of genital plates are nearly of the same size (fig. 4 a, 2), the nght
anterior is the largest, and carries on its front part the madreporiform body; the small
crescentic-shaped single plate forms the posterior boundary of the vent (fig. 472); the
oviductal holes are all near the apices; the sur-anal plate is composed of six or seven
pieces arranged lke mosaic before the anal opening; the ocular plates are small and
firmly wedged between the genital and sur-anal elements. All the plates of the apical disc
have numerous granules scattered on their surface.

The mouth opening is wide, nearly one half the diameter of the test; the peristome is
decagonal ; the ambulacral being larger than the inter-ambulacral lobes, the ten deep

FROM THE GREAT OOLITE. 237

notches, with reflected edges, indent the bases of the inter-ambulacra, and extend as far as
the areolas of the second or third tubercles. ;

The primary spines are finely preserved zz situ in fig. 44; they are variable in size in
the same and in different specimens, and are proportionally shorter in young than in old
urchins ; sometimes they are three times the length of the diameter of the body (fig. 4 4),
and are sometimes nearly three inches and a half in length; the head is conical, with a
truncated extremity marked by deep crenulations (fig. 4 7), the ring is prominent, and the
milling is angular and sharp; the stem (fig. 4 4) swells out beyond the ring, it is more or less
regularly sub-angular, with the angles rounded ; a transverse section of one of the spines
exhibits an irregularly elliptical figure ; sometimes the spine tapers toa conical point, or the
distal end terminates in a bifid or trifid extremity. The secondary spines articulating with
the ambulacral tubercles (fig. 4 ~) are short, about three tenths of an inchin length, they
are round, and taper gently from the ring to the point, their surface being covered with
fine longitudinal lines (fig. 4 7).

The jaws are preserved in one or two specimens (fig. 4 gy); the lantern is strong
(fig. 4 4), the teeth conical, and in its general appearance the dental apparatus closely
resembles that of an Hehinus.

Affinities and differences—This urchin very much resembles a Hencidaris ; in fact,
Acrosalenia and Hemicidaris have so many characters in common, which are always well
preserved, and so few that are diagnostic, and which for the most part are either broken or
absent, that it requires considerable practice, when the apical disc is wanting, to deter-
mine the genus; the absence of semi-tubercles at the base of the ambulacra and the
magnitude and pentagonal form of the discal opening serve as good guides to the
genus. <Acrosalenia hemicidaroides is distinguished from A. Lycettii by having a larger
and more spheroidal test, larger bosses on the sides, and smaller ambulacral tubercles ;
the apical disc is larger, and the sur-anal plate is composed of a greater number of pieces.
Acrosalenia hemicidaroides is distinguished from 4. pustu/ata in having regular rows of
secondary tubercles in the ambulacral areas, which are larger and more fully developed ;
the miliary zone is narrower, with only two rows of granules ; the primary tubercles are
more developed at the upper surface, and the apical disc is hkewise larger.

The same characters distinguish it from 4. Wiltonii ; but besides those already enu-
merated, that species has four rows of fine granules in the miliary zone, smaller tubercles,
suddenly diminishing at the upper surface, and a much smaller mouth opening. The
complex character of the sur-anal plate, the size of the test and of its primary tubercles,
readily separate it from 4. spinosa.

Locality and Stratigraphical position —tThe finest specimens of this urchin with their
spines attached (fig. 4 4) have been collected by Mr. William Buy, from the Forest
Marble, near Malmesbury, in a thin vein of clay, which, according to that acute and

238 ACROSALENTA.

careful collector, separates the Cornbrash from the Forest Marble. The beauty of these
specimens, and the admirable state of preservation in which they are found, forms one of
the marvels of the Oolitic fauna; a great quantity of fine tests are collected from the gray
brashy beds of the Cornbrash near Chippenham. Mr. Bristow obtained it from the Corn-
brash near Wincanton; Mr. Pratt from the Forest Marble at Hinton Abbey; Mr. Hull
found very large specimens in a cream-coloured, calcareous, semi-indurated, marly bed of
the Great Oolite near Burford, in a quarry not far from the Bird-in-hand Inn. I dis-
covered two specimens in the Great Oolite limestone of Minchinhampton Common. The
specimens said to have been found in the Inferior Oolite have been ascertained to be
A. Lycettu. The Rev. A. W. Griesbach collected quinquefid spines of this urchin in the
Great Oolite at Wollaston, Northamptonshire, along with <Acrosalenia pustulata. This
species, therefore, belongs to the Bathonian stage, and is a very characteristic urchin of
this great zone of life.

ACROSALENIA SPINosa, Agassiz. Pl. XVII, fig. 3 a, 4, c, d, e, f.

ACROSALENIA SPINOSA. Agassiz, Catalogus systematicus Ectyporum Echinodermatum
fossilium, p. 9, 1840.
— LAVIS. Agassiz, Catalogus systematicus Ectyporum Echinodermatum
fossilium, p. 9, 1840.
— SPINOSA. Agassiz, Echinodermes Fossiles de la Suisse, ii, tab. 18, figs. 1—5,
bp. 39.
— —_ Cotteau, Etudes sur les &chinides Fossiles, pl. 3, figs. 6—11,
p- 58.
— — Agassiz et Desor, Catalogue raisonné, Annales des Sciences
Naturelles, 3™° série, tome vi, p. 343.
—_ _— Forbes, in Morris’s Catalogue of British Fossils, p. 70.
— — Wright, Annals and Magazine of Natural History, 2d series, vol.
vui, pl. 12, fig. 3, p. 265.
— _ Bronn, Lethza Geognostica, dritte Auflage, Band ii, tabl. xvii,
fig. 7, p. 144.
— _— Desor, Synopsis des Echinides Fossiles, tabl. 20, figs. 14d—16.
— — D’Orbigny, Prodrome de Paléontologie, tome i, 11™° étage, Batho-
nien, p. 320, No. 417.

-— RADIATA. Forbes, Memoirs of the Geological Survey, IV Decade. Note on
new species of British Acrosalenias.

Test sub-pentagonal, depressed ; ambulacra straight, prominent, with two marginal rows
of small spaced-out tubercles ten to twelve in each row; inter-ambulacra with eight to nine
primary tubercles in each row, large at the circumference, gradually diminishing towards the
peristome, suddenly so on the upper surface ; miliary zone narrow at the circumference, wide
and naked in the middle at the upper surface; apical disc large, sur-anal plate single ;

FROM THE GREAT OOLITE. 239

vent large, excentral; mouth large; peristome decagonal, lobes nearly equal; notches
slightly incised.

Dimensions.—Height, nearly four tenths of an inch; transverse diameter, seven tenths
of an inch.

Description—This beautiful little urchin is so admirably preserved in the Corn-
brash of Wiltshire, that it forms one of the most characteristic fossils of that formation ;
the test is small, sometimes circular, oftener sub-pentagonal, and always much depressed
(fig. 3 c).

The ambulacral areas are narrow and prominent (fig. 3 a, 4); as the poriferous zones
are wide, for so small an urchin, the ambulacra appear isolated, and the upper surface of
the test has a radiated appearance, which is increased by the size and smoothness of the
apical disc (fig. 3 a); the ambulacra converge in straight lines from the base to the disc ;
they are furnished with two rows of small tubercles, which, although microscopic in size,
have crenulated bosses and perforated summits; the tubercles are disposed with great
regularity on the borders of the areas, at a moderate distance apart (fig. 3 c, Z7), so that
there are only from ten to twelve in each row; in the middle of the area a double row of
granules separates the tubercles, and lateral rows encircle the areolas, which are only open
on the sides (fig. 3 d). ‘The poriferous zones are wide and straight; the pores are large,
and disposed obliquely in single pairs (fig. 3 d@), forming a rectilinear file on each side of
the ambulacral segments ; there are from five to six pairs of pores opposite each large
tubercular plate.

The inter-ambulacral areas are three times the width of the ambulacral ; the two rows
of tubercles, about eight in each row, are nearly equidistant throughout (fig. 3 a); the
two basal pairs are small (fig. 3 4), the three equatorial pairs large (fig. 3 ¢), and the
three upper pairs suddenly diminish in size and become dwarfed as they approach the
disc (fig. 3 a, c) ; two or three pairs of tubercles at the equator have very large bosses (fig.
3 e), whilst all the others are of moderate size; they have narrow elliptical areolas,
of which the larger are confluent (fig. 3 d); the miliary zone consists of two rows of
granules, which form scrobicular circles around the areolas (fig. 3 d) ; as the rows diverge
above, a small triangular space on the upper part of the segment is left naked (fig. 3 a) ;
the areolas are likewise separated from the poriferous zones by a single row of granules
(fig. 3 d).

The apical disc is large and pentagonal, about two fifths the diameter of the test
(fig. 3a); the anterior and posterior pair of genital plates are nearly alike im size and
form (fig. 3,7); the oviductal holes are perforated near the external third of the plates;
the posterior single plate projects a little further to its corresponding segment than the
others, it is largely excavated for the vent, of which it forms the posterior wall (fig. 3 /) ;
the sur-anal plate is central, single, and pentagonal, and forms the’ anterior wall of the
vent (fig. 3), its sides being tormed by the posterior par of ocular plates, which are

240 ACROSALENTA.

much larger than the three others (fig. 3 f) ; the madreporiform body is very small, and
occupies as usual the right anterior genital plate; a few small granules form central
clusters on the pairs of genitals, and similar granules dot the surface of the small oculars
(fig. 3 /).

The mouth opening is nearly half the diameter of the test (fig. 3 6); the peristome is
decagonal, and divided by small notches into nearly equal-sized lobes; the incisions are
not deep, and the margin is reflected over all the angles (fig. 3 //).

Affinities and differences.—This species is distinguished by its small size and depressed
test, the extreme regularity of its tubercles, the radiated appearance of the upper surface,
the apical disc having the sur-anal plate single, and the vent of a triangular form ; these cha-
racters serve to distinguish it from all its other English congeners. It resembles 4. aspera in
many of its general characters, but that species has undulated ambulacral areas with close-set
tubercles and the sur-anal plate composed of two pieces ; it is so entirely distinct from all
other forms of the genus at present known, that it is unnecessary to pursue a comparison
with them.

Locality and Stratigraphical position—\ have collected two specimens of this urchin
in the Pea grit, Inferior Oolite, at Crickley Hill, and in the yellow clay resting on the
Stonesfield Slate at Sevenhampton, with Anabacia orbulites, Pecten vagans, Ostrea acuminata,
and other Great Oolite fossils. I have likewise found it in the Great Oolite at Sham Castle,
near Bath. Mr. Lycett has collected it from the Great Oolite of Minchinhampton
Common, where it is small in size and rare. It is abundant in the Forest Marble and
Cornbrash near Chippenham, with Avicula echinata, Sow., whence my finest specimens
were collected by Mr. William Buy. It is found, likewise, in the Forest Marble
and Cornbrash near Cirencester; imdeed, it may be considered an abundant fossil
in the English Cornbrash, but I have seen no specimens at all equal in their preservation
and beauty to those found in Wiltshire.

In Switzerland it was collected by M. Strohmeyer from the marls containing Ostrea
acuminata, in the canton of Soleure. In France it has been found in the Great Oolite of
Ranville, Calvados, by Professor Deslongchamps, and in the upper beds of the Bathonien
étage in the environs of Chatel-Censoir, by M. Cotteau.

AcrosaLenta Lowzana, Wright, nov. sp. Pl. XVII, fig. 4 a, 4, ¢, d.

Test circular, much depressed; ambulacral areas narrow and sinuous, with marginal
rows of very small wide-set tubercles; inter-ambulacral areas with six primary tubercles
in each of the two rows, of which the two equatorial pairs are very large; apical disc of
moderate size, sur-anal plate composed of three pieces; primary tubercles near the disc
very small.

FROM THE GREAT OOLITE. 241

Dimensions.—Height, seven twentieths of an inch; transverse diameter, three quarters
of an inch.

Description.—This small depressed urchin was kindly communicated to me by my friend
Mr. S. P. Woodward, and is the only specimen of the form which has come under my
notice. The test is circular, much depressed, and well characterised by the dispropor-
tionate magnitude of the equatorial tubercles, when compared with those on the upper and
under surfaces of the test.

The ambulacral areas are narrow, and slightly undulated ; they have two rows of very
small tubercles on the margins, from twelve to fourteen in each row, placed wide apart
from each other, with a few granules in the interspace (fig. 4 ¢); the poriferous zones are
narrow and undulated, winding round the bulging areolas of the large equatorial tubercles;
there are from eight to nine pairs of pores opposite the large tubercular plates (fig. 4 ¢),
and the septa form mammillated elevations on the surface.

The inter-ambulacral areas are more than four times as wide as the ambulacral (fig.
4 a); they have only six plates in each column (fig. 4 4), each plate bearing a primary
tubercle ; the two equatorial plates support tubercles with very large prominent bosses
(fig. 4 6), which are likewise surrounded by wide, smooth areolas; on three parts of the
margin of these equatorial plates thereis a continuous series of small granules, which are
absent, however, from the lower border (fig. 4 ¢); on the smaller of the larger plates the
bosses become suddenly less, and between the areola and the centro-suture there are three
rows of granules (fig. 4 ¢); the uppermost plate has a mere rudimentary tubercle on its
surface, surrounded with numerous granules (fig. 4 @) ; the basal tubercles likewise sud-
denly diminish in size towards the peristome ; the zones expand in consequence, and the
pairs of pores are disposed im oblique ranks of threes closely laid together.

The apical disc is of moderate size for the genus Acrosalenia (fig. 4 a) ; the four ovarial
plates are shield-shaped, the anterior pair being a little larger than the posterior pair
(fig. 4 7); the single ovarial plate is small and crescentic, the oviductal holes are perforated
near their apices, and the small spongy madreporiform body occupies the centre of the right
anterior (fig. 4 7); the sur-anal plate is composed of three pieces, one central pentagonal
piece, and two small latero-posterior rhomboidal pieces, which form the anterior wall of the
vent (fig. 4 7); the sides of this opening are formed by the posterior genital and ocular
plates, and the posterior wall by the single crescentic genital (fig. 4 7); the three ante-
rior ocular plates are heart-shaped, the posterior pair are rhomboidal, and the eye-holes are
all marginal (fig. 4 d) ; all the plates are moderately large.

The base is flat, the mouth opening large, and the peristome decagonal ; the notches
are deep and have reflected margins; the opening is one half the diameter of the test,
and the ambulacral are larger than the inter-ambulacral lobes.

Affinities and differences.—This urchin at first sight resembles some of the depressed

242 ACROSALENTA.

forms of Acrosalenia hemicidaroides (Pl. XV, fig. 4), but from these it is distinguished by
having fewer primary tubercles in each row, the two equatorial pairs are disproportionately
larger than the others, and those on the upper surface are rudimentary; the apical disc like-
wise is smaller, and the sur-anal plate is composed of three pieces, whilst in 4. hemicidaroides
it has six elements.

It is distinguished from Acrosalenia spinosa in having fewer primary tubercles in the
inter-ambulacral areas, in having the ambulacral areas sinuous, the sur-anal plate with
three elements, 4. spinosa having only one (Pl. XVII, fig. 8 /); it is so entirely distinct
from other congeneric forms that it is unnecessary to make a comparison with them.

Locality and Stratigraphical position—This urchin was collected from the Forest
Marble at Malmesbury, and belongs to the British Museum; the honour of detecting the
species is due to Mr. Woodward, who has kindly communicated it for this work.

I have much pleasure in associating the name of my friend Josiah Graham Lowe, Esgq.,
of Kensington Park, with this Forest Marble species, as a tribute of gratitude for his kind-
ness in presenting me with several rare and valuable specimens for this Monograph, and
as an acknowledgment of the valuable service he {has rendered to the paleontology of the
Forest Marble and Cornbrash formations, so well developed in Wiltshire, in making the
finest collection extant from these rich fossiliferous deposits

ACROSALENIA PusTULATA, Morbes. PI. XVI, fig. 2 a, 6, ¢,d, ef, 9.

ACROSALENIA PUSTULATA. Forbes, Memoirs of the Geological Survey, Decade IV. Notes
to pl. 3.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 70.
_ — Desor, Synopsis des Hchinides Fossiles, p. 143.

Test hemispherical, depressed; ambulacral areas narrow, with two rows of small
tubercles disposed alternately, rather wide apart, on the sides of the area; inter-ambulacral
tubercles large at the equator, gradually diminishing towards the peristome, suddenly
diminishing on the upper surface; miliary zone with four rows of granules; apical disc
staall, sur-anal plate composed of many pieces; mouth opening large; peristome nearly
equally decagonal, notches wide; spines long, slender, tapering; stem flattened, ring
prominent, strize wide apart.

Dimensions.—Height, half an inch ; transverse diameter, one inch.

As the |size of this urchin varies very much, I have selected four specimens, from
different localities in Northamptonshire, and have given their measurements in the follow-
ing table—

FROM THE GREAT OOLITE. 243

l |

Height. Diameter. Mouth opening. | Apical disc. |
Acrosalenia pustulata, Forbes. Py ae a e =
Inch. Inch, Inch. Inch.
1. Large variety, Great Oolite : fy 15 5 4 |
B. Yardley ditto, Great Oolite : 5 Lab 25 | hy
c. Yardley ditto, Great Oolite = l ce | ay
D. Oundle ditto, Forest Marble : <5 044 re a

Description.—I have had much difficulty m making out the history of this species ;
and had it not been for the zeal, industry, and perseverance of my friend, the Rev. A. W.
Griesbach, in obtaining, for the sake of comparison, a fine series of specimens from Oundle,
Yardley, and Wollaston, Northamptonshire, I should have been unable to clear up the
doubts. For several years I regarded the large, inflated forms of this urchin, with
broad miliary zones, as granulated varieties of Acrosalenia Wiltoniz ; the only perceptible
difference consisting in the size of the mouth opening, which is smaller in that species
(Pl. XVI, fig. 3 4) than in Acrosalenia pustulata (Pl. XVI, fig. 2 4). The specimens which had
been collected m Gloucestershire, Oxfordshire and Northamptonshire, were, on an average,
about the size of the one figured in Pl. XVI, fig. 2, whilst Professor Forbes’s type specimen
was only half the size of our urchins ; moreover, his diagnosis, always so correct in reference
to the object he described, “areolis disjunctis, areé centrali angustissima, bigranulata,
granulis sparsis (diam. $ unce., alt. ¢ unc.),” did not agree with those I had hitherto
collected, for their areolas were confluent, and the area centralis was broad, with four rows
of granules. It occurred to me, therefore, that Professor Forbes’s specimen, from the
Forest Marble of Malmesbury, was possibly an immature form of the species. I, therefore,
requested my friend, the Rev. A. W. Griesbach, to obtain specimens of the same age as
those described by Professor Forbes, which he fortunately discovered, and these small
urchins I found agreed very well with his diagnosis.

The ambulacral areas are narrow and straight, they have two rows of small tubercles,
from eighteen to twenty in each row, disposed at some distance apart on the sides of the
area, those at the base (fig. 2 4) are a little larger than those on the sides (fig. 2c); a
double series of granules takes the direction of the zigzag suture, and sends lateral branches
between their small areolas, so that on the upper part of the area these granules are nearly
as large as the small tubercles placed between them (fig. 2 ¢, d).

The poriferous zones are narrow, the pairs of pores are oblique, and the septa form
- moniliform elevations on the surface (fig. 2 d), which produce a bead-like line down the
centre of the zone between the pores ; and there are from eight to nine pairs of pores opposite
each large tubercular plate (fig. 2 d).

The inter-ambulacral areas are nearly four times as wide as the ambulacral ; they have
eight plates in each column, of which the three equatorial pairs support large tubercles

32

244 ACROSALENTA.

(fig. 2c); the three uppermost pairs of plates have mere rudimentary tubercles; the
sudden diminution in size between the fifth and sixth forms a remarkable feature in the
character of this species (fig. 2 a); at the base, the tubercles gradually diminish towards the
peristome (fig. 26). In young shells, and in some adult ones, the miliary zone consists of
two rows of granules ; but, in other varieties, it is formed of four rows, closely set together,
on the upper surface; the plates are covered with numerous equal-sized granules, among
which the rudimentary tubercles are placed (fig. 2 a); the areolas of the three equatorial
tubercles are circular and confluent, the uppermost has a distinct scrobicular circle of
granules, but the others are confluent (fig. 2d), and one row of granules separates the
areolas from the poriferous zones; this description applies to the variety figured, but does
not agree with others. The Rev. Mr. Griesbach, on this point, has made the following
observations: “ Among the very numerous specimens I found at Oundle, there is about an
equal number of two dissimilarly constructed individuals. I pointed this out to you
before (though you had seen it), and it is the same with the Wollaston specimens. When
I found that age would not account for the difference, I was set to thinking about sex,
making inquiries on this subject. Isee from Professor Owen’s lectures on the Invertebrate
Animals, that the ‘sexes are in distinct individuals in the Echinoids as in star-fishes ;’
and Professor Forbes, in Decade UI, ‘Mem. of the Geol. Survey,’ accounts for the
difference in form between some individuals of A/icraster coranguinum, on the supposition
that it may possibly be due to sex. ‘This was all I wanted, to confirm an impression I
had already entertained that the tall, ample form of this Acrosalenia pustulata, Forbes,
with its broad granulated space between the primary tubercles, is the female, and the
depressed one, with a narrow central area, the male. They are, without doubt, the same
species; and I quite believe my sexual hypothesis to be true.” As my excellent friend
has carefully examined a greater number of specimens of this urchin than any other
naturalist, it affords me much pleasure to record his explanation of a difficult problem, and
‘to add that it affords a physiological reason for an admitted fact.

The apical disc is seldom preserved in this species (fig. 2a); m one or two small
specimens the genital and ocular plates are x siéw, but only a portion of the sur-anal
remains; the disc is pentagonal; the anterior and posterior pair of genital plates are
shield-shaped ; the right plate is the largest, and supports im its centre a spongy madrepori-
form body ; the single plate is crescentic, and its body is absent, to give place to the vent;
the three anterior oculars are heart-shaped, and the two posterior pairs are elongated, and
form the sides of the anal aperture; the sur-anal is composed of many pieces; the three
anterior, however, are alone 2” si¢v—one central, and two latero-posterior plates, behind
these there was evidently a series to form the anterior boundary of the vent. ‘The surface
of all the plates 1s covered with numerous granules, similar to those on other parts of the test.

The base is flat ; the mouth opening is large, nearly, but not quite, one half the width
of the equatorial diameter; the peristome is decagonal, with wide notches (fig. 2 4); the
ambulacral, however, being larger than the inter-ambulacral lobes.

FROM THE GREAT OOLITE. 245

The beautiful specimen, on a slab of Great Oolite from Yardley (fig. 2,7), was collected
by Mr. Griesbach, and presented to me for this work; it shows the spines zu situ. The
primary spines are long, slender, and smooth ; in length, once and two thirds the diameter
of the test; they have a small, conical head, with a prominent milled ring (fig. 2 ¢); the
stem tapers gently to the point, a transverse section shows it is somewhat triangular, with
flattened or rounded angles; the surface, alihough apparently smooth, is covered with
microscopic longitudinal lines. The secondary spines are small, stout, dagger-like bodies
(fig. 2 g), with a flattened stem, and covered with longitudinal lines (fig. 2%).

Affinities and differences.—This species closely resembles Acrosalenia Wailtonii, but is
distinguished by the following characters: it has larger equatoyial tubercles, with more
prominent bosses and wider areolas ; the three superior tubercles more suddenly diminish
in size; the miliary zone, even in the large granulated varieties, is narrower, the mouth is
larger, the notches are wider and deeper, the test is more depressed, and the sides less
inflated ; but the most marked character resides in the mouth opening which is small,
being about two fifths the diameter m Acrosalenia Wilton, and nearly one half the
diameter in Acrosalenia pustulata.

Locality and Stratigraphical position—This species has been collected by the Rev.
A. W. Griesbach, from the Forest Marble at Oundle; the Great Oolite at Yardley; and
Wollaston; and also from Strixton, Wimmington, Blisworth, and Kingsthorp, Northampton-
shire. It was collected from the Great Oolite, near Woodstock, by Mr. Gavey; and from
near Kiddington, Oxon, by Mr. Dominicke Brown, who kindly sent me a fine slab, with
fourteen urchins on its surface, which he obtained from a Great Oolite quarry. In
describing this specimen, Mr. Brown observes: ‘On examining the quarry where the
Cidaris (Acrosalenia pustulata) is found, I can seeat once the reason why the shells are
not in a better state of preservation. The Cidarites appear only in a thin layer of rock
not more than a foot or two below the surface, then comes a thick bed of marl, and below
this the solid rock in which I occasionally find spines of Cidarzs, but not often.” This
species has been found by Mr. Bravender, im the Great Oolite and Bradford Clay near
Cirencester, and I have collected two specimens from the Forest Marble near Naunton
Downs, which are both depressed and highly granulated varieties; [ have seen separate
portions of the test on slabs of the Forest Marble near Upper Cubberley, Gloucestershire,
and in the Bradford Clay near the Tetbury-road Station, Great Western Railway, but I
have never seen even a fragment of a specimen in the Great Oolite, of Minchinhampton.

246 ACROSALENTA.

AcrosaLenta Witton, Wright. Pl. XVI, fig. 3 a, 6, ¢, d, e.

ACROSALENIA Witonit. Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 83, pl. 3, fig. 4 a—e.
— == Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 70.

= Lamarckt. Desor, Synopsis des Hchinides Fossiles, p. 141.

Test hemispherical, depressed, sometimes elevated; sides always tumid; ambulacral
areas natirow, straight, with two rows of small perforated tubercles on the margins, set
wide apart, and a miliary zone of three rows of fine granules between the marginal tuber-
cles ; inter-ambulacral areas four times the width of the ambulacral; ten tubercles in each
row—of these the three middle pairs only are developed, the basal are small, and those
at the upper surface rudimentary; miliary zone wide, composed of four rows of small
granules in the middle, and‘six rows above ; apical disc convex and prominent; sur-anal
plate formed of two large and five small pieces; basal angle obtuse, from the tumidity of
the sides; base concave; mouth opening small ; peristome unequally decagonal.

Dimensions.— Height, half an inch ; transverse diameter, one inch.

Description —tThis beautiful little urchin has almost always a more or less elevated
hemispherical test, which is rarely as much depressed as in fig. 3c; the sides are tumid,
and the base is concave ; the ambulacral areas preserve a very uniform width throughout ;
two rows of small perforated tubercles placed wide apart occupy the sides of the area
(fig. 3 d), with from eighteen to twenty in each row; the eight basal pairs are larger, and
the lateral and dorsal pairs smaller, they are arranged closer together, and gradually diminish
in size until they become quite microscopic (fig. 3 7); two or three rows of fine granules
(fig. 3 d) form a miliary zone, which sends lateral branches to divide the small marginal
tubercles.

The poriferous zones are narrow and undulated, the pores are unigeminal, except near
the base, where they are trigeminal (fig. 3 0); opposite each of the large lateral plates
there are eight pairs of pores (fig. 3 d).

The inter-ambulacral areas are four times as wide as the ambulacral ; they have ten
pairs of tubercles; the three basal pairs are small (fig. 3 4), gradually increasmg in size
from the peristome upwards, to blend in with the three lateral pairs, which are the largest
(fig. 3 c, d); the eighth pair are suddenly smaller than the seventh pair, and the ninth and
tenth pairs are quite rudimentary (fig. 3 a) : the miliary zone is wide (fig. 3 ¢), and occupied
by four or five rows of small close-set granules on the sides, increasing to six or seven rows
on the upper surface; between the areolas and the poriferous zones there are likewise two

FROM THE CORNBRASH. 247

rows of granules: the bosses of the four middle pairs of tubercles are moderately large
(fig. 3 e), they have small areolas, which are nearly divided from each other by horizontal
lines of granules; in some they are absent, and the areolas are then confluent.

The apical disc (fig. 3 a) is seldom preserved ; in one specimen however (Pl. XVII, fig. 5),
it is seen to consist of an anterior and posterior pair of ovarial plates, and a single rudi-
mentary ovarial ; the sur-anal plate is composed of two unequal-sized pentagonal pieces,
united with the anterior and posterior ovarials, and six or seven small pieces which form an
arch, extending from the right to the left posterior ovarials, and completing the anterior wall
of the anus (Pl. XVII, fig. 5); the posterior pair of ocular plates form the lateral, and
the single ovarial the posterior boundary of the vent, which is transversely oblong, slightly
excentral (fig. 3 a), and projects into the single inter-ambulacrum. he ocular plates are
heart-shaped and of moderate size, and the eye-holes are very minute; the surface of all
the discal elements is covered with small close-set granules (PI. XVII, fig. 5).

The tumid sides are gently rounded towards the base, which is concave; the mouth
opening is small, being less than two fifths the diameter of the test; the peristome
is unequally decagonal, the ambulacral being one third larger than the interambulacral
lobes.

The fragment of a primary spine shows that it was smooth and cylindrical, and, judg-
ing from its thickness, must have been long; the secondary spines are short and prickle-
shaped, and are sculptured with fine Jongitudinal lines.

Afinties and differences.—This species so very closely resembles Diadema (Acrosalenia)
Lamarckii, Desmoulins, that at one time I thought them identical, and stated as much
in a letter to M. Desor; but from a more attentive study of the form, I now consider
them distinct. 4. Wilton has a more concave base, and a smaller mouth opening
than any other form of the genus at present known. It differs from A. pustulata im
having a wider miliary zone, a greater number of much smaller granules, a more concave
base, and a smaller mouth opening; the same group of characters serve to distinguish it
from A. hemicidarordes and A. Lycettit.

Locality and Stratigraphical position—This urchin was collected many years ago by
Dr. William Smith, from the Cornbrash of Wiltshire. My type specimens were found by
Mr. William Buy, in the Cornbrash, near Sutton-Benger, Wilts, where it appears to be
very rare, and is known as ‘the small-mouthed Cidaris.” Mr. Bravender obtained it
from the Bradford Clay, near Cirencester.

I dedicate this species to my esteemed friend, John Wilton, Esq., of Gloucester, with
whom I have spent many hpapy days exploring the Natural History of different parts of
Gloucestershire.

248 ACROSALENTIA.

ACROSALENIA HEMICIDAROIDES, JUNIOR? Wright. Pl. XVI, fig. 4 a, b.

The small urchin, with spines attached, which forms the subject of fig. 4 a, 4, was
collected by Mr. William Buy, from the same bed of clay, between the Forest Marble
and Cornbrash, from whence Acrosalenia hemicidaroides (Pl. XV, fig. 4\ was obtained.
At first, this specimen was thought to be distinct from that species, in consequence of the
spines being more cylindrical; but as the test agrees with undeniable tests of A. hemz-
cidaroides, about the same size, I am disposed to consider the difference in the form of the
spines as depending on age. It may, however, hereafter be found to be a distinct species,
although in the mean time, until better evidence is obtained, I regard it as the young of
A. henucidarordes, the materials at my disposal not enabling me to draw up a diagnosis.
Fig. 4 a shows the upper surface of the test, with the primary spines 7z situ, the longest of
which is once and two thirds the length of the diameter of the test; the head and milled
ring agree in form with the same parts of the spine in 4. hemicidaroides; the stem swells
out a little in the middle, and tapers gently to the point; the sides are slightly flattened
(fig. 4 5), and the surface is covered with fine, longitudinal lines: the secondary spines
are short, stout, dagger-like bodies, on the surface of which the longitudinal lines are more
distinctly marked, and the milled ring is proportionally more prominent than in the
primaries.

Locality and Stratigraphical position —F¥rom the band of clay between the Forest
Marble and Cornbrash, near Malmesbury, where it was associated with 4. hemicidaroides
and numerous stems and fragments of Pentacrinus.

AOROSALENIA RADIATA, Hordes, nov. sp.

“A. ambulacris angustis, tuberculis parvis seriebus, duobus approximatis alternatis sub-
divergentibus dispositis ; inter-ambulacrorum tuberculis numerosis regulariter graduatis,
superne decrescentibus centro-lateralibus mediocribus, areolis disjunctis; area centrali
angusta pauci granulata, granulis sparsis.

“ Diameter, seven twelfths of an inch; altitude, three tenths of an inch.

“Tt has affinities with 4. spinosa, but differs in having the primary tubercles regularly
diminishing instead of suddenly decreasing above.” (Mus. Pract. Geol.)

Locality.—Collected by Mr. Lycett in the Great Oolite of Minchinhampton.

FROM THE CORAL RAG. 249

I have made the above extract entire from Professor Forbes’s note on undescribed
species of Acrosalenia, Decade IV, pl. 3, of the ‘Memoirs of the Geological Survey.’
After a careful comparison of the type specimen in the Museum of Practical Geology,
in Jermyn Street, with a large series of Acrosalenia spinosa, I have in my collection, from
the Great Oolite of Minchinhampton, and of Ranville, Calvados, and from the Cornbrash
of Wiltshire, I can detect no persistent specific character in 4. radiata; the upper inter-
ambulacral tubercles are larger than in many specimens, but in others, the same gradual
diminution observed in 4. radiata prevails in a large series ; in fact, the links between a
sudden diminution and a gradual diminution are abundantly supplied ; for these reasons
I consider 4. radiata, Forbes, as a synonym of A. spinosa; the structure of the apical
disc, and of its smgle sur-anal plate, are the same in both.

ACROSALENIA ASPERA, Agassiz.

Professor M‘Coy has entered this species in his list of Mesozoic Radiata,* contained in
the Geological Collection of the University of Cambridge, giving as the localities of the
species “Great Oolite, Minchmhampton, Inferior Oolite, Dundry.” Having seen this
specimen, I can state that I believe it to be a small 4. hemicidaroides from Minchinhamp-
ton. The origial Acrosalenia aspera, Agass., was found by M. Gressly in the Kimme-
ridge Clay of Banné, near Porrentruy, only a single specimen of which is known. I
have never seen an urchin from Minchinhampton, nor Dundry, which resembled this Swiss
species.

D. Species from the Coral Rag.

ACROSALENIA DEcoRATA, Haime. Pl. XVII, fig. 1 a, 6,0, d,¢e, fi g,h, m.

MILNIA DECORATA. Haime, Annales des Sciences Naturelles, 3™° série, tom. xii,
Zoologie, 1849, pl. 2, figs. 1—3, p. 217.
ACROSALENIA DECORATA. Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 81, 1851.
— — Forbes, Memoirs of the Geological Survey, Decade IV, pl. 3, 1852.
= — Cotteau, Notes sur les Echinides de Pétage Kimméridgien du dép.
Aube, Bulletin Soc. Géol. de France, 2d série, tom. xi, p. 355,
1854,
— — Forbes, in Morris’s Catalogue of British Fossils, 2d edit., p. 69,
1854.
— — Desor, Synopsis des Echinides Fossiles, p. 143, 1856.
— _ Cotteau, Etudes sur les Echinides Fossiles, p. 322, 1856.

* © Annals and Magazine of Natural History,’ 2d series, vol. ii, p. 419.

250 ACROSALENTA.

Test sub-pentagonal, depressed on the upper surface, concave at the base; ambulacral
areas convex and prominent, the anterior and posterior pairs slightly sinuous, with two
rows of small marginal tubercles, and the intermediate space filled with very small close-set
granules ; inter-ambulacral areas with from eight to ten tubercles in each row, the four
equatorial tubercles very large, those on the upper surface very small; apical disc large,
sur-anal plate composed of eight pieces; vent elongated and extremely excentral; base
concave ; mouth large; peristome equally decagonal ; primary spines long, smooth, slender,
and tapering; secondary spines small, hair-like.

Dimensions.— Height, four tenths of an inch; transverse diameter, nime tenths of an

inch.

Description.—This elegant little urchin is remarkable among its congeners for its
pentagonal form, arising from the flatness of the inter-ambulacral areas and the convexity
and prominence of the ambulacral, and likewise for exhibiting in a most remarkable
manner the bilateral symmetry of the Sanzntapaz (fig. 1 a).

The ambulacral areas are one fourth the width of the inter-ambulacral; the anterior
single area is quite straight, and the anterior and posterior pairs are sometimes slightly
curved (fig. 1 a); the apices of the anterior pair curve gently backwards, and those of the
posterior pair upwards and inwards (fig. 1 a); two rows of small secondary tubercles, from
twenty to twenty-four in each row, occupy alternately the margins of the area (fig. 1 d),
those at the base and circumference being much larger (fig. 1 e, 2) than those on the upper
surface (fig. 1 d); the mtermediate space is occupied with four rows of very small close-set
granules (fig. 1 d, e) ; both the tubercles and granules are extremely regular im their size
and arrangement throughout the areas.

The poriferous zones are narrow and depressed, which increases the prominence of the
ambulacra; the pores are unigeminal throughout, except just at the base, where they fall
into indistinct ranks of threes (fig. 1 6, 2); there are from eight to nine pairs of pores
opposite each large tubercular plate (fig. 1 e); and the septa are slightly elevated on the
surface.

The inter-umbulacral areas are four times as wide as the ambulacral (fig. 1 c, e), they
are so much flattened that they form nearly straight lines at the circumference; each
segment is composed of two rows of primary tubercles, about eleven in each row (fig. | ¢),
which are unequally developed in different regions of the area ; the four basal pairs (fig. 1 4)
are small, the three equatorial pairs large (fig. 1 ¢), and the four dorsal pairs dwarfed and
rudimentary (fig. 1 d, e); from the first to the eighth pair, the areolas are oval and confluent
(fig. 1 e), whilst those on the upper surface are surrounded by clusters of granules (fig. 1 @) ;
the miliary zone is broad, and composed at the equator of six rows of small close-set
granules (fig. 1); on the upper surface the granules cover all the surface of the plates, the
eight rudimentary tubercles appearing as only larger granules in their midst (fig. 1 c, d);

FROM THE CORAL RAG. 251

between the areolas and the poriferous zones there is another band of granulations,
composed of three rows of larger granules, among which a few secondary tubercles rise at
intervals (fig. 1 e), so that this species has wider granulated inter-tubercular bands than
any other ACROSALENIA.

The large apical disc is oblong (fig. 1 a), with the vent excentrical, and placed so far back
that it encroaches considerably on the single inter-ambulacrum (fig. 1 g) ; the two anterior
pairs of genital plates are the largest (fig. 1 g), the posterior pair are smaller, and the single
plate is extremely elongated ; the body is absent, and the plate is represented by a thickened
semi-lunar border with a reflected margin (fig. 1 g); this plate extends far down the
single segment, and appears as if excavated for the passage of the vent (fig. 1 a); the
ovarials are shield-shaped, and have the perforation for the ducts near their apex. The
ocular plates (fig. 1 g) are small heart-shaped bodies, wedged between the genitals and
the apices of the ambulacral areas, the three anterior ones are symmetrical, and the two pos-
terior unsymmetrical, and slightly produced backwards ; the eye-holes are lodged in the mar-
ginal sinus ; the sur-anal plate is large (fig. 1 7), and composed of several pieces ; namely, one
central pentagonal plate, two smaller lateral rhomboidal plates behind the first, another pen-
tagonal posterior to these two, and four smaller lateral pieces, making in all eight plates
(fig. 1 f); these five small plates form the anterior wall of the opening for the vent, which
occupies nearly the entire area of the single ovarial plate (fig. 1 g); the surface of the
discal elements is covered with the same-sized delicate granules (fig. 1 /) as those which
adorn the miliary zones (fig. 1 d).

The base is concave, the mouth opening large, one half the diameter of the body; the
sides are tumid and rounded, so that the mouth appears to lie in a deep depression (fig.
1 4); the peristome is decagonal and nearly equal-lobed, the notches are wide and have
the margin reflected all round the rim (fig. 1 4); the equatorial tubercles are extremely
prominent, and their bosses are conoidal, with deeply crenulated summits (fig. 1 2).

The primary spines (fig. 1 2) are seen zz sifu in the specimens on the slab (fig. 1 /), some
of them are one and a half the diameter of the test ; they are sub-cylindrical, subulate, and,
to the naked eye, appear smooth, but with the lens are seen to be finely striated ; they
are often slightly curved near their bases, and have their milled rings set obliquely ; the
head is small and conical, and the milling of the ring not well marked (fig. 1 7); a trans-
verse section shows that the stem is slightly flattened (fig. 1 2).

The secondary spines (fig. 1 m) are very small, rather stouter im proportion to their
length, and more distinctly striated than the primary spines (fig. 1 m): the head is larger,
and the milled ring more prominent.

Afinities and differences.—This species differs so much from all its congeners, that it
cannot be mistaken for either of them. In its general character it approaches Acrosalenia
spinosa, but is distinguished from that species by its pentagonal form, the smallness of
the superior inter-ambulacral tubercles, the concavity of the base, the width of the notches,

33

252 ACROSALENTA.

the equal size of the peristomal lobes, the magnitude of the apical disc, the compound
character of the sur-anal plate, and the great excentricity of the vent; the fineness and
abundance of the granulation which adorns the test fully entitles it to the name decorata.

Locality and Stratigraphical position.—I have collected this beautiful Acrosalenia from
the seams of yellow clay which traverse the Coralline Oolite near Calne, Wilts, and from
the limestone of the same locality associated with Hemicidaris intermedia, Pseudodiadema
mamillanum, and Echinobrissus scutatus. The specimens in the Museumof Practical Geology
were collected by the officers of the Geological Survey, from the Coral Rag at Steeple
Ashton, Wilts, and near Abbotsbury Castle, Dorset ; some of the specimens in the British
Museum were obtained from the Coralline Oolite at Malton, Yorkshire.

It has been recently collected by M. Cotteau, “dans les couches Kimméridgiennes
inférieures des environs de Bar-sur-Aube.’’*

Fistory.—tThis species was first figured and described in the twelfth volume of the ‘ An-
nales des Sciences Naturelles,’ by M. Jules Haime, asa remarkable urchin, “ which he had
seen in the collection of the British Museum, on the supposition that it exhibited characters
not met with in any known genus of sea-urchins, and that it combined the anal arrangements
of the CassipuLID# with the usual characters of the C1paRipa#, an union of structures
not hitherto observed.” For this apparent anomaly, he proposed the genus Milnia,
which he considered as the type of a new family, designated by him PsrupociDaRipEs,
and mistaking Malton, the locality from which this type specimen came, for Malta,
he considered it as probably a tertiary species. Mr. Woodward, who was previously
aware that the urchin thus erroneously described was an Acrosalenia, directed
Professor Forbes’s attention to the type specimen which was selected as the subject for
plate 3, Decade IV, of the ‘Memoirs of the Geological Survey,’ where it is beauti-
fully figured, with full details of structure. My lamented friend, knowing that I had
collected this urchin in an excursion I made into Wiltshire, and being informed that
I was engaged in writing a description of it in my memoirs, kindly communicated a
proof impression of that plate to me: finding that it was deficient both in the anatomy of
the apical disc and in the structure of the spines, I supplied Professor Forbes with the
materials for both, which were then incorporated in his plate. It was fully described
in my ‘Memoirs on the Cidaride of the Oolites,’ and afterwards by Professor Forbes
in his description of plate 3, Decade IV, of the ‘Memoirs of the Geological Survey
of Great Britain.’ As a foreign species, it was first found by M. Cotteau, and recorded
in his ‘Note sur les Echinides de l’étage Kimméridgien. du dép. l’Aube,’ and after-
wards was described in his valuable work on Fossil Echinoderms.t+

* «Bulletin Soc.Géol. de France,’ 2° série, tom. xi, p. 355, 1854.
+ Cotteau, ‘Etudes sur les Echinides Fossiles du département de l’Yonne.’

253

NOTES

On Fore1cn JURASSIC SPECIES OF THE GENUS ACROSALENIA NEARLY ALLIED TO

BritisH FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE EneuisH Oo.ites.

AcrosauentaA Lamarckit, Desmoulins. Syn. Diadema Lamarckui, Desmoulins, Tabl.
Synon., p. 316.
Hypodiadema Lamarckii, Desor, Synop. Echin.
Foss., tabl. 10, figs. 1—5.

Test small, inflated at the sides; ambulacra straight, with two marginal rows of small,
distant, marginal tubercles, and a miliary zone of fine granulations between the rows;
inter-ambulacral tubercles large at the equator, the three uppermost pairs rudimentary ;
miliary zone wide, composed of six rows of granules at the equator, which cover the whole
surface of the plates on the upper surface; mouth opening small, base flat, peristome
pentagonal, apical disc convex, sur-anal composed of several (six to eight) pieces.

Dimensions.—Height, half an inch; transverse diameter, nine tenths of an inch.
Spines, according to M. Desor, “en forme de petits batons cylin-
driques, d’apparence lisse, a bouton haut.”

Formation.—Cornbrash (Bathonien) de Marquise ; abundant.

Collections.—In all English and Foreign public collections. My cabinet.

AcrosaLenta Boucnarpil, Desor. Synopsis des Echinides Fossiles, p. 142.

Test globular, depressed on the upper and under surfaces; ambulacra narrow, with
two marginal rows of small tubercles, and a double row of granules between them ; inter-
ambulacral tubercles, nine in each row, diminishing gradually in size from the equator

254 FOREIGN OOLITIC ACROSALENTAS.

towards the disc and peristome; miliary zone moderate in width, and composed of four
rows of granules; mouth opening large, peristome decagonal ; discal opening large.

Dimensions.—Height, eight tenths of an inch; transverse diameter, one inch and four
tenths.

Formation.—Cornbrash (Bathonien) Marquise.
Collections. —British Museum, Neuchatel Museum, M. Bouchard, M. Michelin, my
cabinet. M. Desor states that this species is often ticketed in Conti-

nental collections by mistake, Hemicidaris Luciensis, d’Orbigny ; the
latter is altogether a different urchin.

ACROSALENIA GRANULATA, Mervan. Syn. Hemicidaris granulata, Merian, in Agassiz’s
Catalogue raisonné, Annal. Sc. Naturelles,
tome vi, p. 339, 3™° série.

A small, depressed species. 'The ambulacral tubercles are so small that they resemble
miliary granules; the tubercles of the inter-ambulacral areas are disposed at some

distance apart.

Formation.—“ Grande Oolite (Vesulien) de Gensingen (Argovie), avec les Dysaster
analis, Holectypus depressus,’ &c. Desor.

Collections.—Museum Bale, Collection M. Mesch. Very rare.

ACROSALENIA ELEGANS, Desor. Synopsis des Hchinides Fossiles, p. 143.

This species, according to M. Desor, resembles the preceding. It is larger, but has a
small mouth opening, and the ambulacral tubercles are excessively small.

Formation.—“ Grande Oolite (Vesulien) du Kornberg (Argovie), avec la précédente.

“« Oollection—Meesch.” Desor.

FOREIGN OOLITIC ACROSALENIAS. 25!

or

ACROSALENIA LENS, Desor. Synopsis des Kchinides Fossiles, p. 143.

According to M. Desor, this is the smallest species of the genus. It is about the
size of a lentil, and is well characterised by its close-set inter-ambulacral tubercles, of
which there are from nine to ten in a row.

Formation.—* Grande Oolite (Vesulien) de la cluse de Pfeffingen prés Bale.

“ Collection.—Museum Bale. Exemplaire unique.” Desor.

ACROSALENIA RADIANS, Agassiz. Syn. Hemicidaris radians, Agassiz. Catalogue raisonné
des Echinides, Annal. Sc. Naturelles, 3™° série, tom. vi,
p. 339.

Test hemispherical, depressed ; ambulacra narrow, with two rows of small, prominent
tubercles ; inter-ambulacral tubercles, nine in a row, large at the equator, small above ;
miliary zone with two rows of granules in the middle; the median suture naked, and
depressed at the upper surface; mouth opening large; peristome nearly equally decagonal,
with wide notches; discal opening small.

Formation.—Kellovien de Vivoin, Courgains (Sarthe), Saimt-Aubin (Calvados).

Collections —MM. Michelin, Rouault; my cabinet. The type specimen kindly sent
me by M. Michelin.

ACROSALENIA INTERPUNCTATA, Quenstedt. Handbuch der Petrefactenkunde, pl. 49,
figs. 3 and 4.

‘Test small and much depressed ; ambulacra very narrow ; inter-ambulacra wide, with
large, spaced-out tubercles ; apical disc large; sur-anal plate single, smaller than the other
plates ; eight punctuations at the angles between the genitals, oculars, and sur-anal plate ;
five of these are at the inner angles of the eye-plates, and three around the circumference
of the sur-anal plate ; the five oviductal holes are very small.

256 FOREIGN OOLITIC ACROSALENIAS.

Formation.—The White Jura « of Nattheim = Coral Rag.

Collection.—Museum of Tibingen.

AcrosaLenia Kanicu, Desmoulins. Syn. Diadema Kenigit, Desmoulins. Etudes sur
les Echinides, Tabl. Synon., p. 312, No. 10.
Hemicidaris Konigii, Agassiz. Catalog.
raisonné des Echinides, Annal. Sc. Natu-
relles, 3"° série, tome vi, p. 337.
Hemicidaris Boloniensis, Cotteau, in Desor’s
Synopsis des Echinides Fossiles, p. 53.

Test hemispherical, base flat, sides inflated; ambulacra narrow, straight, with two
rows of small, marginal tubercles, and a double row of granules within ; inter-ambulacra
more than three times as wide as the ambulacra, with two rows of large primary tubercles,
eight to nine in each row; the bosses of the tubercles large, with wide, oval areolas ; miliary
zone composed of two or three rows of granules; apical disc small, the right anterior _
genital plate supports a large, prominent, spongy madreporiform body; single genital
plate small and crescentic ; sur-anal compound, number of pieces unknown; mouth
opening large; peristome unequally decagonal; primary spines long, cylindrical, and
tapering.

The discovery of a portion of the sur-anal plate, 2m situ, added to the excentral position
of the vent, and the absence of semi-tubercles from the base of the ambulacra, are my
reasons for removing this urchin from the genus Hemcidaris, and placing it in Acrosalenia.
I have, at the same time, retained M. Desmoulin’s specific name.

Dimensions.—Height, one inch (?) ; transverse diameter, one inch and three quarters.
Mr. Davidson’s specimen exceeds these dimensions.

Formation.—Etage Kimmeridgien, Ningles, near Boulogne-sur-Mer.

Collections.—British Museum, MM. Michelin, Desmoulins, Cotteau, Bouchard-
Chantereaux, Davidson, my cabinet. The two largest specimens I
possess were collected, and kindly given me, by M. Bouchard. The
species is rare, these two specimens being all that eminent palzon-
tologist collected in thirty years. Mr. Davidson has figured, in his
original manuscript plates, a very beautiful specimen contained in his
collection, which has the spines 2x sztw.

FOREIGN OOLITIC ACROSALENTAS. 257

AcRoSALENIA Woopwarpl, Wright, nov. sp.

Test spheroidal, depressed ; ambulacral areas narrow, with two rows of small tubercles
placed very obliquely in the upper part, a single row of granules between them; inter-
ambulacral areas four times as wide as the ambulacral, with few tubercles in each row ;
bosses large and rather prominent ; tubercles widely perforated ; apical disc moderate, four
and a half lines in diameter; genital plates unequal, anterior pair largest ; ocular plates
small; sur-anal plate composed of several pieces.

Primary spines three inches and a quarter long, and one line and a half thick, some
three inches long, and less than one line in their greatest thickness; tapering, and some-
times forked, at the extremity ; very finely striated, or granulo-striated on the surface.

Secondary spines three lines long, slender, cylindrical, poimted, and striated.

Dimensions.—Height (?) ; transverse diameter, thirteen lines.
Formation.—Cornbrash? British ?

Collection —British Museum.

AcrosALENIA HunreEri, Wright, nov. sp.

Test conoidal; ambulacral areas narrow, with two rows of small tubercles; inter-
ambulacra with two rows of moderate-sized tubercles; test very much elevated; apical
disc absent ; its form, and excentral position, with the absence of semi-tubercles, at the
base of the ambulacra, indicate its acrosalenian character.

Formation.— Unknown. I found this urchin in the celebrated John Hunter’s collec-
tion. Not having access at present to the specimen, I am unable to give a more correct
diagnosis of its specific characters.

Collection.—Hunterian Museum, Royal College of Surgeons, London.

258

Fanuly 6—KCHINOCONID.

GaLERITES (pars), Desor, 1842.
ECHINONEIDES (pars), Agassiz and Desor. 1847.

This natural family includes urchins which have the mouth opening central, or
sub-central, and the vent excentral. Their test is thin, with a circular or sub-pentagonal
circumference ; the upper surface in general is elevated, and sometimes even conical ;
the ambulacral areas are simple and lanceolate; the poriferous zones extend without
interruption from the mouth to the apical disc, and the pores are unigeminal, except near
the mouth, where they lie in triple oblique pairs. ‘The inter-ambulacral areas are wide,
the tubercles are small and perforated; they are arranged with more or less regularity
on the plates, and supported on bosses which have either smooth or crenulated summits.
In some genera, they form regular vertical and concentric rows, and the inter-tubercular
surface is covered with small granules, which form complete circles round the base of the
tubercles.

The mouth opening is circular, central, or sub-central, and the peristome is more or
less divided by notches into ten lobes. The organs of mastication consist of five jaws,
which appear to resemble those of the Eoutnipz.

The anal opening is always large and excentral; it has an oblong or pyriform shape,
and is either dorsal, marginal, infra-marginal, or basal, sometimes occupying the entire
space between the mouth and the border.

The apical disc is mostly central and vertical, composed of five ovarial and five ocular
plates; the right antero-lateral plate is very large, and extends backwards into the centre
of the disc; it supports on its surface a prominent, spongy madreporiform body ;
the anterior and posterior pairs of ovarials are perforated, whilst the single posterior plate
is imperforate ; and the five small ocular plates are perforated near the margin.

The spines are small, short, conical appendages, with a smooth head, and having
the stem covered with longitudinal microscopic lines.

I include in this extinct family the genera Holectypus, Discoidea, Echinoconus, Pygaster,
and Hyboclypus. The Holectypr are found mostly in the Oolitic rocks, the Discoidee
and Hehinocont are true Cretaceous forms, the Hyboclypi are Oolitic, and the Pygasters are
common to the Oolites and Chalk, although they had their greatest development during
the Oolitic age. ‘The oldest types are the Pygasters and Hyboclypi, which were created
about the same time, at the commencement of the deposition of the basement beds
of the Inferior Oolite.

259

Genus—HOLECTYPUS, Desor, 1847.

Discorpks (pars), Klein. 1734.
Ecuinites (pars), Leske. 1778.
GaLeRiteEs (pars), Lamarck. 1816.
Discompea (pars), Gray. 1835.

The genus Holectypus was established by M. Desor for the reception of those
Discoidee which are deprived of ribs, or projecting processes, on the inner wall of
the test; the species referred to this group constitute one of the oldest types of the
Ecutnocon1p&, and are met with chiefly in the Oolitic rocks. They form, according to the
views of the late Professor Forbes, “a section or sub-genus of the Galerites, more valuable
on account of their paleontological merits, and limited distribution in time, being in the
main characteristic of the Oolitic period, than for the zoological importance of the
characters of their organization, which are rather transitional than distinctive.” *

The test is thin, circular, or sub-circular, more or less hemispherical, conical or sub-
conical, always tumid at the sides, and flat or concave at the base.

The ambulacral areas are narrow, straight, and lanceolate, with six or eight rows
of small tubercles, of which the marginal rows only extend from the base to the apex.

The poriferous zones are narrow, and the pores are unigeminal throughout.

The inter-ambulacral areas are three times the width of the ambulacral, the large
pentagonal plates support numerous small, perforated tubercles, which are very regularly
arranged in vertical and concentric rows (Pl. XVIII, fig. 1d). They are raised on bosses
with crenulated summits, and surrounded by ring-like areolas; numerous minute granules
are scattered over the surface of the plates, and form circles around the tubercles
(Pl. XVIII, fig. 1 e).

The mouth opening is circular, and situated in the centre of the base; the peristome
is divided by obtuse notches into ten equal lobes (fig. 1 4). The organs of mastication
consisted of five jaws, which are preserved zz sifu in the specimen figured at 1 g.

The anal opening is large, inferior, infra-marginal, rarely marginal, sometimes
occupying the entire space between the mouth and the border.

The apical disc is nearly central and vertical, composed of five ovarial and five. ocular
plates; the right antero-lateral ovarial is much the largest, and extends into the centre of
the disc; it supports a prominent, convex, madreporiform body; the anterior and
posterior pairs of ovarials are perforated; whilst the single plate is imperforate ; the five
ocular plates are small, triangular bodies, with marginal perforations (fig. 1 2).

* ‘Memoirs of the Geological Survey,’ Decade III, pl. 6, Holectypus hemisphericus.
34

260 HOLECTYPUS.

The internal moulds of Holectypus want those depressions occasioned by ribs
projecting from the inner walls of the test, which so well characterise Descoidea.

The spines are short, with a smooth head, and milled ring; and they have the surface
sculptured with fine, longitudinal lines.

The Holectypt are distinguished from the Hehinocont by having a larger mouth
and vent, a concave base, and a less-elevated dorsal surface; and from the Discoidee
in having tumid sides, a larger mouth and vent, and the absence of ribs from the internal
wall of the test.

The small crenulated tubercles, and basal vent, with the absence of any aperture
in the upper surface of the inter-ambulacrum, distinguishes the Holectypt from the
Pygasters ; and the want of a longitudinal valley in the inter-ambulacrum separates them
from the Hyboclypi. '

The Holectypi are abundant chiefly in the Oolitic rocks ; two of the species are found
in the Neocomian and the Chalk. They make their first appearance in the Inferior
Oolite, in the zone of the Ammonites Parkinsoni, Sow.

A. Species from the Inferior Oolite. = 10° Etage Bajocien, D’Orbigny.
Hoxectypus pepressus, Leske. Pl. XVIII, fig. 1 a, 6,¢,d¢, fig, &, 2.

Jacob. a Melle de Echinitis Wagricis, tab. 1, fig. 2, 1718.
Kundman, Rariora Nature, tab. 5, fig. 12, 1737.
Briickner, Merkwirdigkeiten der Landschaft. Basel, tab. 22,
figs. G, H, 1748-63.
Van Phelsum, Brief. de Gewelvslekken of Zee-egelen, p. 31, No. 16
(Zgelsteen tienband plattop), 1774.
Knorr, Petrefactions, vol. ii, tab. , ui, figs. 6, 7, 1775-78.
Favanne, pl. 67, figs. 1, 2.
EcHINITES DEPRESSUS. lLeske, Additamenta ad Kleinii Echinodermata, p. 164, pl. 41,
figs. 5, 6, 1768.
EcHINUS DEPRESSUS. Linneé, Systema Nature, Gmelin, p. 3182.
GALERITES DEPRESSUS. Lamarck, Animaux sans Vertebres, tom. ii, p. 21, 1816.
_ — Deslongchamps, Ene., tom. ii, p. 432; Encyl. Méthod., tab. 152,
figs. 7, 8.

— — Defrance, Dict. des Sciences Naturelles, tome xviii, p. 86, 1820.
ECHINITES ORIFICIATUS. Schlotheim, Jahrb., 1813; Petrefactenkunde, p. 317, 1822.
GALERITES DEPRESSUS. Goldfuss, Petrefacta Germanic, Band i, p. 129, tabl. 41, fig. 3,

1826.

—_ — Phillips, Geology of Yorkshire, tab. 7, fig. 4, 1829.

— — De Blainville, Zoophytologie, p. 204, 1830.

_ DEPRESSA. Leonhard and Bronn, Jahrb., 1834, p. 135.

— — Desmoulins, Etudes sur les Hchinides, p- 254, No. 6, 1835.

— _DEPRESSUS. Grateloup, Mémoire sur les oursins Fossiles (Dax), p. 56, No. 9,

1836.

FROM THE INFERIOR OOLITE. 261

GALERITES kapIaTUS. Valenciennes, Encyclopéd. Methodique, tab. 153, figs. 1, 2
(Explication des Planches).
— _ DEPRESSA. Koch and Dunker ? Norddeutschen Oolithgebildes, p. 40, tab. 4,
fig. 2 a, b, 1837.
HoLecrypus pEPREssUS. Bronn and Romer, Lethza Geognostica, 3° Auflage, Band ii,
p. 148, tab. 17, fig. 5 a, 6, 1851.
DIscOIDEA DEPRESSA. Agassiz, Prodromus, p. 86, 1837.
— — Agassiz, Echinodermes Foss. de la Suisse, part i, p. 88, tab. 13,
figs. 7—13, 1839.
— = Desor, Monographie des Galerites, p. 65, tab. 10, figs. 4—12,
1842.
Ho.ectypus pEepressus. Desor, Catalogue raisonné, Ann. des Sc. Nat., 3™° série, tom. vil,
p. 145, 1847. :
— — Albin Gras, Oursins Fossiles du département de l’Isére, p. 41,
1848.
—_— — Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 94, 1851.
— _ Forbes, in Morris’s Catalogue of British Fossils, 2d edit., p. 82,
1854.
Desor, Synopsis des Bchinides Fossiles, p- 169, 1857.

Test thin, hemispherical, sometimes conoidal, more or less depressed; circumference
circular, or sub-pentagonal, and slightly contracted posteriorly; base flat, or a little
concave; mouth central; peristome nearly equally decagonal, with reflected margin ;
anal opening large, pyriform, occupying nearly all the space between the mouth and
the border; ambulacral areas lancet-shaped, with from six to eight rows of tubercles
at the circumference, arranged in two oblique rows; inter-ambulacral areas with from
sixteen to twenty rows of tubercles, which form a single row on the centro-sutural half of
each plate, and two or three rows on the zonal half of the same; apical disc small, four
genital plates nearly equal sized, the right antero-lateral large, with the madreporiform body
projecting into the centre of the disc.

Dimensions.—Cornbrash specimen. Height, nine tenths of an inch; transverse
diameter, two inches and two tenths of an inch; antero-posterior
diameter, two inches and two tenths.

Inferior Oolite specimen. Height, seven tenths of an inch; transverse
diameter, one inch and a quarter; antero-posterior diameter, one
inch and seven tenths.

Description —This is one of the most ubiquitous Echinites of the Oolitic rocks, and
as its synonymy shows, has been long known to naturalists. In different formations
it attains various degrees of development, being small in the Inferior Oolite, but large in
the Cornbrash, as shown by the measurement of the specimens from these two stages.

The form is sub-conoidal, or more or less depressed ; the circumference is circular, or
sub-pentagonal, with the postero-lateral border a little compressed, and the single

262 HOLECTYPUS.

inter-ambulacrum slightly produced and truncated (fig. 1 @,6). The ambulacral areas
are one third the width of the inter-ambulacral; they have a lanceolate form, and
taper gradually from the border to the disc; at the circumference there are
eight rows of tubercles, which are disposed so as to form double oblique

rows) thus") miaMe “ (fig. 1d). In the upper part of the areas the immer

rows disappear, and the test is depressed in the line of the median suture (fig. 1 a).

The inter-ambulacral areas are three times as wide as the ambulacral, each plate
supports a number of tubercles, one row represents the principal range, and extends from
the peristome to the disc, and the tubercles of this row are a little larger than the others
on the upper surface, but nearly of the same size on the sides and base. Between
this primary row and the centro-suture, the tubercles are arranged in a single line
on the same plane; but between it and the poriferous zones they form three super-
imposed rows (fig. 1 d), so that the zonal side of the plates contains many more tubercles
than the central half. The tubercles are surrounded by sunken areolas; they have
crenulated bosses and perforated summits, and the intermediate surface of the plates is
covered with a fine, abundant, miliary granulation. The tubercles at the base are much
larger, they have deeper areolas, and are all disposed in single, concentric rows (fig. 1 4).

The poriferous zones are extremely narrow, and the pores are unigeminal throughout.
The septa are elevated above the surface, and form a moniliform line between the pores
(fig. 1 d), of which there are eight pairs opposite each inter-ambulacral plate.

The apical disc is well preserved in many of our specimens. Fig. 17, is an accurate
drawing of this part (fig. 1q@). The anterior and posterior pairs of genital plates
are perforated, but the single posterior plate is imperforate; the antero-lateral plate
is very large, and extends into the centre of the disc; it supports a prominent, spongy,
madreporiform body, which forms the summit of the test, and occupies the centre of
the disc; not, however, as a new element introduced into the centre of the genital circle,
but formed simply by the development of the right antero-lateral plate. The ocular plates
are small, heart-shaped bodies, inserted between the genitals (fig. 17), with the eye-holes
perforated near their margin (fig. 172); all the discal plates are covered with small
tubercles, similar to those which form the miliary granulation. In M. Desor’s ‘Monograph
on the Galerites,’ tab. 10, fig. 7a, the eye-holes are represented as marginal, and the
madreporiform body is figured and described as distinct from the genital plates.
It is probable that the imperfection of his specimens led the learned author into these
errors, which we have now the pleasure of correcting by our better examples. The under
surface is slightly concave, the mouth opening is central, and upwards of one third
the diameter of the test (fig. 14). The peristome is nearly equally decagonal, and
the notches are wide, with reflected margins. In one specimen, collected by Mr. William
Buy, from the Forest Marble of Wiltshire, the jaws are preserved im sitw (fig. 14g).

FROM THE INFERIOR OOLITE. 263

Although the structure of the peristome in the Ecurnoconip# led us to infer the
existence of jaws in the entire family, still we had only feeble traces of them in Hehinoconus
albo-galerus, Klem, and Pygaster umbrella, Agass. Our discovery of these organs in
Holectypus depressus, Leske, is a fact new to science; each jaw consists of two slender
branches united near the apex, and supports a long, slender, prismatic tooth (fig. 1 g).

The anal opening is large and pyriform, with the apex directed towards the mouth ;
it occupies nearly all the space between the mouth and the border, and is therefore
situated entirely at the base of the shell (fig. 1 4); the direction of the apex of the vent
inwards, and its basal position, form important diagnostic characters, by which this
species is clearly distinguished from its congeners. The tubercles situated at the
base, are much larger and more fully developed than those on the upper surface (fig. 1 /),
but imstead of having a circle of granules around the areolas, they are separated laterally
from each other by sharp elevations of the test, the upper and under sides of the areolas
being bounded by crescents of granules (fig. 1 /).

Many spines are preserved zz sz¢u on the shell (fig. 1 gy); they have a long, conical
head, with a prominent ring, and a slender, tapering stem, which is sculptured with
numerous longitudinal lines (fig. 1 4); the apex is blunted. Besides these primary spines,
which were articulated with the largest tubercles, I find the miliary granulation at
the base likewise possessed fine, hair-like spines, as they are observed in connection with
their granules among the larger spines at the under surface (fig. 1 g).

Afinities and differences.—Holectypus depressus, Leske, may be regarded as the best
type of this genus. It is distinguished from H. hemisphericus, Desor, by its more depressed
form, basal vent, and more acute marginal fold. The apex of the pyriform anal opening
is directed towards the mouth, whilst in H. hemisphericus, it is just the reverse.

It is distinguished from /. odlongus, Wright, by the form of the test, which is circular
or sub-pentagonal, whereas in that Coral Rag species it has an oblong shape; the
tubercles on a portion of the inter-ambulacral plates form a single line of tubercles,
whilst in H. oblongus they are disposed in double lines on the same plate (fig. 3 d).

Locality and Stratigraphical position —This urchin is found for the first time in the
Upper Ragstones of the Inferior Oolite, in the zone of Ammonites Parkinsoni, Sowerby.
I have collected it from the Trigonia Grit, wherever that bed is present, along the whole
range of the Cotteswold Hills, as at Dundry, Wotton-under-Edge, Stinchcombe,
Rodborough, Coopers, Birdlip, Shurdington, Leckhampton, and Sudeley Hills; and at
Hampen, Naunton, and Stow-in-the-Wold, likewise in the Cornbrash near the Kemble
Tunnel, and in the neighbourhood of Cirencester, Gloucestershire. It is found rarely in the
Cornbrash near Chippenham, but abundantly in that formation near Trowbridge, Wilts,
whence I have a very fine series of large specimens in the finest preservation, collected
by Mr. Macniel.

264 HOLECTYPUS.

The Rev. A. W. Griesbach has collected the finest specimens I have seen in
the Cornbrash near Rushden, Northamptonshire ; the beautiful specimens fig. 1, a, and 6,
are two of these, kindly presented for this work. ‘The Cornbrash specimens are always
larger and finer than those collected from the Inferior Oolite. Mr. Gavey obtained it from
the Cornbrash near Woodstock, Oxon.; and it is found abundantly at Scarborough, in
the Cornbrash near the Castle Hill.

Houctypus HEMIsPHmARICUS, Agassiz. Pl. XVIII, fig. 2 a, b,c, d,e, f, 9, h, +.

DIscOIDEA HEMISPHMRICA. Agassiz, Catalogus Systematicus, p. 7.
— — Desor, Monographie des Galérites, pl. 8, figs. 4—7, p. 71.
HoLECTYPUS HEMISPH@RICUS. Agassiz et Desor, Catalogue raisonné des Echinides, Annal.
des Sc. Nat., 3™ série, vol. vii, p. 146.

GALERITES HEMISPHHRICUS. Forbes, Memoirs of the Geological Survey, Decade III,
pl. 6.
DISCOIDEA MARGINALIS. M‘Coy, Annals and Magazine of Natural History, 2d ser.,
vol. i, p. 413.
HoLEctTYPus DEVAUXIANUS. Cotteau, Etudes sur les Echinides Fossiles, pl. 2, figs. 7—9,
p- 46.
— HEMISPHA@RICUS. Wright, Annals and Magazine of Natural History, 2d ser.,
vol. ix, p. 96.
—_— — Forbes, in Morris’s Catalogue of British Fossils, 2d edit.,
p. 82.

— — Desor, Synopsis des Echinides Fossiles, p. 172.

‘Test hemispherical, more or less depressed; sides tumid ; margin rounded ; posterior
half of the test longer than the anterior; single inter-ambulacrum slightly produced ;
anal opening marginal, large, and pyriform, with the apex directed upwards; base nearly
flat ; mouth opening small.

Dimensions.—Height, eight tenths of an inch; transverse diameter, one inch; antero-
posterior diameter, one inch and a quarter.

Description.—The marginal vent of this urchin sufficiently distinguishes it from its
congeners. It is very abundant in some localities, but rare in others; it appears to have
had a very limited life in time, having been hitherto only found in a marly vein, about
an inch in thickness, which traverses the Trigonia bed of the Inferior Oolite, in the zone
of Ammonites Parkinsoni, Sow. I have examined many hundreds of specimens of this
Echinite, which all came from the same bed.

M. Desor has given a very good figure of this species in his ‘Monograph on the
Galerites,’ which appears to have been the small conical variety.

FROM THE INFERIOR OOLITE. 265

Professor Forbes has given most beautiful figures, with full details, of Holectypus
hemisphericus, in Decade III, pl. 6, which leave nothing more to be desired.

The general outline of this urchin is sub-hemispherical, but it is more or less
convex in different individuals; some varieties are depressed, and others are conoidal,
but few specimens are regularly convex; most commonly they have a slight obliquity,
from the test in a majority of specimens being slightly elongated in the antero-posterior
diameter, and declining on the side towards the vent; the vertex is therefore not quite
central, and the apical disc is nearer the anterior than the posterior border; the sides
are a little tumid, and the margin is gently rounded thereby.

The ambulacral areas are about one third the width of the inter-ambulacral ; from
the border to the disc they are quite conical, and taper gradually between these two
points; there are six rows of tubercles at the margin, which gradually diminish to four
and two on the upper surface; the two outer rows alone extend from the peristome to
the disc ; each pair of the small, narrow ambulacral plates (fig. 2 d) supports one tubercle,
which occupies the same relative position thereon on every fourth plate, so that the
areas are adorned at their widest part with six rows of tubercles, arranged obliquely

in v-shaped lines, thux— - ° “haul: - In a specimen one inch and a quarter in dia-

meter I counted one hundred and twenty plates in each column. The poriferous zones
are narrow, the pores are strictly unigeminal, and there are from four to five pairs of pores
opposite each inter-ambulacral plate.

The inter-ambulacral areas are rather more than three times the width of the
ambulacral (fig. 2 a); the number of plates in each column varies with the age of the
urchin ; in the one before me there are thirty-two plates; those on the sides are slightly
bent upwards in the middle, whilst the basal plates are nearly straight; each plate
supports one or two tiers of tubercles, the number and arrangement of which varies
exceedingly in different individuals; fig. 2 d shows a common distribution of the
tubercles on the plates near the margin; besides these spinigerous tubercles, the entire
surface of the plates is covered with a fine, close-set, miliary granulation, from the midst
of which the tubercles appear to arise; near the margin, in one specimen there are
sixteen tubercles abreast in one inter-ambulacral area; the tubercles become crowded
towards the margin; they increase in size at the base (fig. 2 /), but the number on the
plates in this region is inconsiderable. The perforated tubercles are raised on crenulated
bosses, which are surrounded by a sunken areolas; at the base many ‘of these are
encircled by perforated granules (fig. 2 2).

The apical disc is small (fig. 2 a, and formed of five genital, and five ocular
plates; the pairs of genital plates are shield-shaped and perforated; the single plate is
imperforate ; the right anterior genital plate is the largest, and extends into the centre of
the disc, supporting on its surface the spongy madreporiform body. The ocular plates

266 HOLECTYPUS.

are small pentagonal bodies, wedged between the angles formed by the ovarials and the
summits of the ambulacra; the eye-holes are large, and pierced near the lower border
(fig. 2 e), their axis having a slanting direction upwards. The surface of all the
discal elements is covered with close-set, miliary granules, similar to those on the surface
of the plates.

The vent occupies the margin of the single inter-ambulacrum (fig. 2 ¢); its form is
pyriform, with the rounded base extending half way into the ventral surface (fig. 2 4), and its
apex directed upwards towards the apical disc (fig. 2 ¢, g). The widest or basal portion
of the vent occupies the outer half of the space between the peristome and the margin
(fig. 2 4), and the apex extends one fourth of the distance between the base and the
disc (fig. 2 g), but these proportions vary considerably in every individual I have
examined ; the marginal opening for the vent, however, is a constant diagnostic character
of the species.

The mouth opening is small, being rather more than one fourth the diameter of
the test ; the peristome is equally decagonal, the notches are wide and rounded, with the
margin reflected (fig. 2 4); the base is concave; and the oral opening lies in a central
depression of the ventral surface.

Among the many hundreds of specimens which I have examined, the specific
characters above described are retained in all with remarkable persistence ; still there are
certain points, such as differences in the amount of convexity, the proportion between the
height and the breadth, the distance between the vent and the mouth, and the number
and regularity of the tubercles, which vary in certain specimens; they may all, however,
be reduced to three principal types.

Var. a. Hemisphericus, represented by our fig. 2 a, 6, ¢.

Var. B. Conicus, represented by our fig. 2 g.

Var. y. Depressus, with the upper surface much depressed, but the vent marginal.

In the following table I have embodied the comparative dimensions of six specimens
from six different localities in Dorsetshire :

Height. Breadth. | Anus to Mouth.
No. Locality.
Inch. * Inch. Inch.
l Stoke Knaps . : : : . a ] is
2 Loders : 1 : ‘ d a5 l= <5
3 Crewkerne . i 3 : F +p; Ls qT
4 Castle Cary . é : ‘ 3 aa tr zr
5 Bridport Harbour : . : . re Tz ¥s
6 Walditch ; : 4 A 5 on 144 <b

FROM THE INFERIOR OOLITE. 267

Affinities and differences—The tumid sides, convex upper surface, and marginal vent
of Holectypus hemisphericus serve to distinguish this species from all its congeners, and by
these characters it is readily separated from all other Holectypi.

Locality and Stratigraphical position—In the stratigraphical position of this
species, | am at issue with the statement made by Professor Forbes, who remarks :
“ During the examination of the Inferior Oolite strata in Somersetshire and Dorsetshire,
by the members 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), Pilcombe, Bruton, Shipton Gorge, Burton
Bradstock, and near Burton Castle (top beds), Bridport Harbour, Chideock Hill,
Mapperton, West Swillets, Beaminster.”*

I have never seen this urchin lower than the marly vein which traverses the upper
ragstones in the zone of Ammonites Parkinsoni, Sow.; where I have found it with
Cidaris Bouchardii, Wright; Stomechinus bigranularis, Lamarck; Clypeus Agassizii,
Wright ; Clypeus altus, M‘Coy; Hypoclypus gibberulus, Agassiz; Ammonites subradiatus,
Sow.; Ammonites Parkinson, Sow.; Terebratula spheroidalis, Sow.; Rhynchonella
plicatella, Sow. It is true, that in many of the localities in the above list, the ragstones
rest on the sands of the Inferior Oolite; a collector, therefore, might readily obtain speci-
mens from the sands which had dropped out of the marly seam, and thereby conclude that
they belonged to that formation; but I have shownt+ that the so-called sands of the
Inferior Oolite belong to the upper region of the Upper Lias, to the zone of Ammonites
Jurensis, Zieten, and Ammonites variabilis, dOrbig., and that, as far as we at present
know, urchins have not been found in this bed.

I have collected Holectypus hemisphericus from the Trigonia grit at Shurdington, Leck-
hampton, and Hampen, in Gloucestershire, associated with Pedina rotata, Wright ;
Holectypus depressus, Leske; Echinobrissus clunicularis, Lilhwyd; Echinobrissus Hugi,
Agass. ; Clypeus Plottii, Klein ; Ammonites Parkinsoni, Sow. ; and Terebratula globata, Sow.

B. Species from the Coral Rag= 14° Ftage Corallien, @Orbigny.

Ho.erctypus ostonevs, Wright, nov. sp. Pl. XVIII, fig. 3 a, 6, ¢, d.

Test oblong, inflated at the sides, depressed at the upper surface; anterior half of
the test shorter, broader, and rounder than the posterior half, which becomes narrow,

* ¢Memoirs of the Geological Survey,’ Decade III, pl. 6, pp. 4, 5.
+ ‘Quarterly Journal of the Geological Society,’ vol. xii, p. 292.
35

268 HOLECTYPUS.

and has the single inter-ambulacrum produced; anal opening at the base; tubercles on
the upper surface very small and indistinct; those at the base and margin moderately
large ; mouth opening concealed.

Dimensions.—Height, seven tenths of an inch; transverse diameter, one inch and a
quarter ; antero-posterior diameter, one inch and four tenths.

Description.—The few specimens of this urchin I have examined were not in good
preservation, the surface of the test having been more or less rubbed in them all, so much
so, that a detailed description, with the materials at my disposal, is at present impossible.

The test is oblong, with tumid sides; it is rounded before, contracted and elongated
behind, so that the anterior half is an eighth of an inch shorter than the posterior half,
when measured from the disc to the border (fig. 3 a).

The ambulacral areas are one third the width of the inter-ambulacral; they have six
rows of small tubercles, which form v-shaped lines throughout the area; the poriferous
zones are narrow; and there are five pairs of pores opposite each inter-ambulacral plate
(fig. 3 d).

The inter-ambulacral spaces are of equal width, and three times as broad as the
ambulacral (fig. 3 a); from the disc to the border there are twenty plates in each column,
which are all slightly bent in the middle; on some of the plates there is only one row of
tubercles, but in the others there are two rows, arranged as in fig. 3 d, which are small
and indistinct from friction; the basal tubercles of both areas are larger, and they are
arranged in single concentric lines.

The base is much concealed in all the specimens I have seen; the mouth is entirely,
the vent partially so, in those before me; the anal opening appears to be a large aperture,
situated between the mouth and the border, but encroaching a little upon the latter; and
has the apex directed towards the mouth.

The apical disc is small, vertical, and excentral, being nearer the anterior than the
posterior border; the ovarial plates are small, with the exception of the mght antero-
lateral, which is nearly twice as large as the others, and supports an oblong, madreporiform
body; the ocular plates are very small, and perforated near their border.

Affinities and differences.—This species very much resembles #. depressus, Leske ; but
it has a more oblong form, more tumid sides, and the anal opening is nearer the
border than in that species; by the smallness of the tubercles it is distinguished from
fT, corallinus, VOrbigny, and by the arrangement of the tubercles on the plates from
FH. depressus ; the basal position of the anus separates it from H. hemisphericus, Agassiz.
The imperfect condition of all the specimens I have seen renders a more critical comparison
at present impossible.

Locality and Stratigraphical position.—The four or five specimens I have examined
were all collected from the Coralline Oolite of Malton, Yorkshire.

269

NOTES

On Foreign Jurassic sPECcIES OF THE GENUS HOLECTYPUS, nearLy aLLiep To

Britisu FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITEs.

Hoxxcrypus pLANus, Desor. Monogr. des Galérites, tab. 9, figs. 1—3.

Test small, flat, pentagonal; dorsal surface convex, base concave; tubercles on the
upper surface small, about ten rows in the inter-ambulacra at the circumference, basal
tubercles much larger; mouth small, central; vent small, occupies only half the space
between the mouth and the border.

Dimensions.—Height, seven twentieths of an inch; transverse diameter, three quarters
of an inch.

Formation.—Oxford Clay, Vaches-Noires, Normandy.

Collections—M. Michelin, my Cabinet. Very rare.

Horxzcrypus Manpetstouti, Desor. Monogr. des Galérites, tab. 9, figs. 14—16.

Test sub-conical; tubercles small on the upper surface, large at the base, arranged
in vertical and horizontal rows; mouth small; vent at the base nearly as wide as
the mouth; miliary granulation abundant, and close-set.

Dimensions.—Height, nine twentieths of an inch; transverse diameter, eight tenths
of an inch.

Formation —Corallien inférieur (terrain 4 chailles), Albe Wurtembergeoise, Lusberg
(Canton du Soleure). ‘“Argovien (avec Dysuster granulosus) du
Randen de Birmansdorf, de Baden.” Desor.

Collections —Count Mandelslohe, M. Gressly, M. Moesch. Mus. Bale, Mus. Neuchatel.

270 FOREIGN JURASSIC HOLECTYPI.

Hotxcrypus puncruLatus, Desor. Monogr. des Galérites, tab. 9, figs. 17—19.

Test hemispherical, sides tumid; tubercles form regular, horizontal, and vertical
series, ten rows in the inter-ambulacra, and six rows in the ambulacra, which are much
more developed at the base ; mouth small, vent large, between that opening and the border.
This species has many important affinities with the preceding, and is only distinguished
from it, according to M. Desor, by having fewer tubercles, which are arranged with
greater regularity.

Dimensions.—Height, four tenths of an inch; transverse diameter, eight tenths of
an inch.

Formation.—Corallien inférieur de Largue (Canton de Berne), Dettingen, Wiirttemberg,
Mont-de-Bregille (pres Besancon). Oxfordien de Chambery. Renevier.

Collections.—MM. Gressly, Parandier ; Count Mandelslohe. Abundant.

Hotzcrypus coraLuinus, d Orbig. Cotteau, Etudes sur les Echinides Foss., pl. 32,
figs. 1—8.

Test sub-pentagonal, sub-conical above, flat or sub-concave below; tubercles disposed
in regular, vertical, and concentric series, a single longitudinal row on each plate, small
and few in number on the upper surface, large and numerous at the circumference
and base, about twelve in the widest part of the inter-ambulacra. Granules unequally
scattered on the surface of the plates. Mouth central, peristome deeply notched; vent
large, elliptical, between the mouth and the border.

Dimensions.—Height, eleven twentieths of an inch; transverse diameter, one inch and

a quarter.

Formation.—Corallien 14° étage, d’Orbig.; Druyes, Chatel-Censoir (Yonne).
Kimméridgien 15° étage. Pointe-du-Ché (Yonne). Cod¢eaw.

Collections. —MM. Cotteau, d’Orbigny. Abundant.

FOREIGN JURASSIC HOLECTYPI. 271

Hoxxcrypus arEnatus, Desor. Monogr. des Galérites, tab. 9, figs. 11—13.

The tubercles, although very numerous, are disposed with great regularity ; the miliary
granules form continuous horizontal series; mouth opening small, with rows of oblong
granules near the peristome; in its general form it resembles H. punctulatus, Des.,
and H. Mandelslohi, Des., and is distinguished from these species only when the details
of the test are well preserved.

Dimensions.—Height, four tenths of an inch; transverse diameter, eight tenths of
an inch.

Formation.—Oxfordien du Canton de Soleure. Very rare.

Collection.—M. Gressly.

Hoxecryrus specrosus, Minster. Syn. Galerites speciosus, Goldfuss, Petref. German.,
tab. 41, fig. 5 a, b.
Discoidea speciosa, Agass., Echin. Foss. Suisse,
tab. 6, fig. 16. (zoz.)
— a Desor, Monogr. des Galeérites,
tab. 10, fig. 13. (won.)

Test large, depressed; the plates of the ambulacral and inter-ambulacral areas very
narrow in proportion to their length; tubercles on the upper surface small and irregularly
disposed ; tubercles at the base larger, and arranged in double horizontal rows, closely
placed together on each plate; mouth opening small, peristome decagonal; anal opening
large, pyriform, occupying half the space between the border and the peristome.

Dimensions.—Height, one inch and a half; transverse diameter, three inches and
three quarters.

Formation.—Kimmeridge Clay of the valley de La Birse, near Lanfon (Greifel) ;
Upper Stage of the Calcaire Jurassique de Heidenheim (Wirtemberg).

Collections.—Count Minster, M. Gressly.

272 FOREIGN JURASSIC HOLECTYPI.

Honecrypus INFLATUS, Agassiz. Syn. Discoidea inflata, Agassiz, Echinoderm. Foss.
Suisse, tab. 6, figs. 4—6.
—_ — Desor, Monogr. des Galérites,
tab. 9, figs. 7—10.

‘Test thin, small, and depressed, with tumid, inflated sides ; tubercles small, numerous,
twelve rows in the inter-ambulacra, and four in the ambulacra; miliary granules do not
form horizontal series; mouth opening small and decagonal; anal opening, very large
and pyriform, extending from the peristome to the border, with the apex directed
towards the mouth.

Formation.—“ Portlandien inférieur (Astartien) du Jura Neuchatelois.

“Collections —Museum of Neuchatel. Coll. M. Gressly.” Desor.

Houucrypus e1canreus, Desor. Syn. Discoidea speciosa, Agassiz, Echinoderm. Foss. de
Suisse, tabl. 6, fig. 16.
a — Desor, Monogr. des Galérites,
tabl. 10, fig. 13.

“A very large, depressed species. The base is furnished with numerous close-set
tubercles, but without a regular arrangement; mouth opening proportionally very small ;

anal opening pyriform, hardly occupying half the space between the peristome and the
border.”

Formation.—*‘ Corallien de la Vallée de la Birse.

“ Collection —M. Gressly; very rare.’ M. Desor adds, in a note to the above
description, in his ‘ Synopsis des Echinides Foss.,’ that it is by mistake this species has been
confounded by M. Agassiz and himself with H. speciosus, Miinst. The arrangement of
the tubercles is very different in H. giganteus ; the regular concentric disposition observed
in H. speciosus is absent in H. giganteus; their regular distribution in the one, and
irregular distribution in the other, form a diagnostic character between these two gigantic
FTolectypi.

Genus—PYGASTER, Ayassiz. 1834.

GaLErites? (pars), Lamarck. 1816. (?)
Ciyreus (pars), Phillips. 1829.
EcuHINOCLYPEUS (pars), De Blainville. 1830.
NUcLEOLITES (pars), Desmoulins. 1837.

It is by no means certain that Lamarck was acquainted with the urchins now included
in the genus Pygaster, although he is invariably cited as the.author of one of the most
typical species of the group, for reasons which will be given in the article on Pygaster
umbrella ; it appears that Lamarck’s reference to Klein’s tab. 12 was an error. In his
genus Echinoclypeus, De Blainville associated three distinct types of Echinides,—Clypeus,
Pygaster, and Conoclypeus ; whilst Desmoulins placed the Pygasters with his Nucleolites,
urchins which have limited petaloidal ambulacra, wide poriferous zones, small and irregular-
disposed tubercles, with a five-lobed edentulous mouth ; characters which are quite opposite
to those possessed by the Pygasters. The only explanation that can be given for these
errors of arrangement by authors of such eminence, is the fact that neither De Blainville nor
Desmoulins had seen a Pygaster, as appears from a note by the latter author, appended to
his description of the species in his ‘Synonymie générale.’*

M. Agassiz has the merit of having first detected and pointed out the leading characters
of the genus Pygaster, which he established from a figure of the only species then known,
and which has subsequently been proved to be one of the most natural and best-defined of
all the genera of the EcHINOIDEA EXOCYCLICA.

The test is sub-pentagonal, more or less elevated and convex on the upper surface, and
concave at the base; the ambulacral areas are narrow, with four or six rows of small
tubercles, the marginal rows only extending from the base to the apex of the areas.

The poriferous zones are narrow, simple, and complete; and the pores are strictly
unigeminal throughout.

The inter-ambulacral areas are in general four times the width of the ambulacral ; each
of the large pentagonal plates supports numerous tubercles, and those at the border have
from six to eight. The tubercles are more or less regularly arranged in vertical and
horizontal rows ; it is only the representatives of the two primary rows of each area which
extend from the mouth to the disc, all the others disappear in succession on the sides, and
the length of each is in proportion to its proximity to the two primary rows. The tubercles
are small, and nearly equal-sized; they are perforated, and raised on bosses with smooth,
uncrenulated summits; depressed, ring-like areolas surround their base; and the inter-

* «Htudes sur les Echinides,’ p. 354, No. 2.

274 PYGASTER.

tubercular surface of the plates is covered with numerous small miliary granules, which
form circles around the areolas. The basal tubercles are larger than those on the upper
surface, their areolas are more excavated, and they have a quadrate or hexagonal figure,
which makes a striking contrast to their circular form on the upper surface.

The apical disc is large, composed of five ovarial and five ocular plates; the right
antero-lateral ovarial is the largest, it extends into the centre of the disc, and supports a
large madreporiform body on its surface. The five ocular plates are small, and wedged
between the angles left by the ovarials.

The anal opening is situated on the upper surface of the single inter-ambulacrum ;
it is a very large, oblong, or pyriform aperture in the test, and in the living urchin appears
to have been closed by a tegumentary membrane; in all the species at present known,
P. pileus excepted, the discal and anal openings are continuous; but in that species
a portion of the test separates the apical disc from the vent. »

The mouth opening is circular, and situated im a depression in the centre of the base ;
the peristome is divided by deep notches into ten equal-sized lobes. Remains of jaws have
been found in some species ; and imprints of ten care, radiating from the centre to the
periphery, are seen in the moulds of others. ‘The Pygasters, therefore, possessed mastica-
ting organs probably allied in structure to those I have already described in Holectypus
depressus, Leske.

The spines are small, short appendages, which resemble the same parts in Echinus,
and, like them, their surface is covered with well-marked longitudinal lines.

The Pygasters form a type of structure which nearly approaches the Hemzpedinas,
of the family Diapumap#; like them, the tubercles are perforated, their bosses have
smooth, uncrenulated summits, and they are arranged in regular vertical and horizontal
rows. ‘The poriferous zones are narrow and unigeminal; the mouth opening is circular
and decagonal; and they possess organs of mastication.

Unlike the Diaprmapa#, however, the Pygasters are true exocyclous urchins, and have
a large vent, placed without the circle of the apical disc. ‘They differ from Ho/ectypus in
having the tubercles larger, and the vent at the upper surface ; and from Hyboclypus in the
absence of the dorsal sulcus in which the vent is situated in that genus. They are
distinguished from Clypeus, Echinobrissus, Catopygus, Pygaulus, and other EcutnosrissiDa&,
in having perforated tubercles arranged in rows; narrow, complete poriferous zones ; and
the mouth armed with jaws. They form, in fact, a well-defined group of urchins, separated
by prominent organic characters from all the others.

The Pygasters first appeared in the lowest beds of the Inferior Oolite ; and their different
species are discovered in the Cornbrash, Calcareous Grit, Coral Rag, and Kimmeridge
Clay. They have been found likewise in the Gault.

FROM THE INFERIOR OOLITE. 275

A. Species from the Inferior Oolite=10° Htage Bajocien, @Orbigny.

Pyeasrer semisutcatus, Phillips. Pl. XIX, fig. 1 a, 6, ¢, def, 9.

CLYPEUS SEMISULCATUS. Phillips, Geology of Yorkshire, vol. i, p. 104, pl. 3, fig. 17

(two thirds nat. size), 1829.
— ORNATUS. Buckman, in Murchison’s Geology of Cheltenham, 2d ed.,

p- 95, 1845.

NUCLEOLITES SEMISULCATA. Desmoulins, Etudes sur les Hchinides, Tabl. Synoptique, p. 362,
1837.

PYGASTER SEMISULCATUS. Agassiz, Prodrome d’une Monogr. des Echinodermes, p- 185,
1837. }

— — Dujardin, in Lamarck’s Hist. Naturelle des Animaux, 2™ édit.,
tome ill, p. 353, 1840.

—_ BREVIFRONS. M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. ii, p. 414.
— SEMISULCATUS. Wright, Annals and Magazine of Natural History, 2d series,

vol. 1x, p. 89, 1852.

— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 88,
1855.

= — Desor, Synopsis des Echinides Fossiles, p. 165.

Test sub-pentagonal, depressed, sometimes conoidal; ambulacral areas prominent and
convex, with four rows of tubercles at the margin, diminishing to two marginal rows
above; inter-ambulacra four times the width of the ambulacra, with from eighteen to
twenty vertical rows of tubercles at the margin, diminishing to two rows in the upper part ;
marginal fold acute, base flat, towards the centre very concave; mouth sunk in a depres-
sion, peristome nearly equally decagonal; discal opening wide, central; anal opening
large, semisulcate, not contracted towards the disc, extending one half the distance
between the centre of the apical disc and the posterior border.

Dimensions.—Height, one inch and a half; transverse diameter, three inches and one

eighth.

Description—I have omitted from the list of synonyms the Galerites umbrella,
Lamarck, because that species is clearly the Clypeus sinuatus, Leske; likewise the
Pygaster umbrella, Agassiz, of the ‘Echinodermes Fossiles de la Suisse,’ and of Desor’s
‘Monographie des Galérites,’ inasmuch as the figures given in these works represent,
probably, another British species. It is extremely doubtful whether Pygaster semi-
sulcatus has been yet found out of the English Inferior Oolite; it was said to have been
discovered in the Bajocien stage of the department of the Sarthe, but M. Cotteau informs
me that. the specimen supposed to have been collected therefrom, turns out to be a
Gloucestershire fossil, which had got by mistake into a collection of Chauffour urchins.

36

276 PYGASTER.

When Professor Phillips figured Pygaster semisulcatus in his ‘ Geology of Yorkshire,’
he was not aware that two distinct species of the genus Pygaster existed in the Oolites of
that county, one collected from the Inferior Oolite of Whitwell, and the other from
the Coralline Oolite of Malton; as the type specimen is now lost, it is uncertain whether
the Whitwell or Malton urchin was the one sketched in tab. 3, fig. 17 of that work.
When Professor Forbes was studying this species, he applied to Professor Phillips for the
type of P. semisulcatus, and the one sent was a Whitwell specimen, which I compared
with my Inferior Oolite urchins, and ascertained the identity of the species.

It was assumed, therefore, by Professor Forbes, that the Whitwell urchin was
P. semisulcatus, and his beautiful plate of this species, in the fifth Decade of the
‘Memoirs of the Geological Survey,’ was lettered accordingly.

The general form is sub-hemispherical, more or less depressed on the upper surface ;
the base is flat or slightly concave, and the mouth is lodged in a considerable central
depression ; the circumference is sub-pentagonal, and the bilateral symmetry of the test is
very evident in specimens which are free from distortion (fig. 1 a); the upper surface is
in general convex (fig. 1 ¢), but sometimes in large examples the sides are flattened, and
the test then assumes a conoidal figure, when it becomes the P. drevifrons, M‘Coy.

The ambulacral areas are equidistant, and of equal width, and about one fourth
the breadth of the inter-ambulacral areas; the anterior single area is straight and
lancet-shaped ; the anterior pair are gently bent backwards, and the posterior pair in
large individuals have a slight fshaped flexure, occasioned by the great width of the vent
(fig. 1 a). They are composed, according to the size of the test, of from one hundred and
twenty to one hundred and sixty pairs of plates, as weathered specimens show that every
third plate carries a primary tubercle (fig. 1 7). There are two complete rows of tubercles
on the margins of the areas, which extend without interruption from the peristome to the
disc ; in each row there are about fifty-eight tubercles ; of these, twenty-two belong to the
base and margin, and thirty-six to the sides and upper surface (fig. 1 a, 6); within these,
two other rows commence about half an inch from the peristome, and extend from thence
three quarters of an inch up the sides, about which pomt they disappear; at the mar-
ginal angle sometimes a fifth, or in some cases a sixth, row is introduced for a very
limited extent, and the miliary zone in the upper part of the area is filled with small granu-
lations. The poriferous zones are narrow; the pores are strictly unigeminal throughout,
one pair of pores nearly corresponding to each of the ambulacral plates. ‘The pores con-
stituting a pair are placed slightly oblique; in some specimens the inner hole is round
and the outer is oval, but this character is individual, and not general. ‘The septa are
narrow, and form very inconsiderable elevations on the surface (fig. 1 7, 4).

The inter-ambulacral areas are four times the width of the ambulacral; they are
composed of about thirty-five pairs of plates, of which about fifteen occupy the base,
and twenty the sides; these plates, according to their breadth, support a variable number
of tubercles, those at the margin having from nine to ten tubercles on the same horizontal

FROM THE INFERIOR OOLITE. 277

line (fig. 1 @). Two of these rows, the fifth on each side from the centro-sutural line, repre-
sent the primary tubercles, and extend from the peristome to the disc; the other rows,
as the plates become narrower, disappear at various points on the sides, so that, whilst at
the margin of the specimen (fig. 1 d@) there are twenty rows of tubercles, in the vicinity
of the apical dise there are only two rows (fig. 1 a). The tubercles are nearly of the same
size, and form very regular horizontal and vertical rows on both areas; those of the
primary rows are larger in the upper surface, and all the basal tubercles are so likewise.
The tubercles, which are perforated, are raised on small bosses, with smooth summits
(fig. 1 e, f) ; their base is encircled by narrow, sunken, ring-like areolas, which are much
more developed around the ventral than on the dorsal tubercles; the circumference
of the areolas is surrounded by a circle of small granules, and the intervening portion
of the plates is covered with a like-sized miliary granulation (fig. 1 d, e, /).

The opening for the apical disc is very large, half an inch in diameter, but in only one
of the hundreds of specimens of this species which I have examined has a vestige
of the plates remained. ‘These consist of four ovarial, and three ocular ; the ovarial plates
are small, and dove-tail with the angular incisions in the discal opening; the spongy
madreporiform body is large, extending inwards and backwards, and the ovarial holes are
perforated near the apex; the ocular plates are very small, situated at the summit of the
ambulacral areas, and the eye-holes are perforated near their margin ; as the centre of the
disc is absent ; the form of its posterior boundary is therefore unknown.

The anal aperture is a very large, oblong-oval opening, which occupies nearly the
upper half of the single inter-ambulacrum (fig. 1 @). Its shape forms an important
diagnostic specific character, and ought to be carefully noted in making determinations
of the species. The borders of the opening are incurved, and the vent appears to
have lain in a depression ; at the point where the plates incline towards the lateral parts
of the vent, two tumid ridges extend downwards to the posterior border, having a
slight concave depression between them (fig. 1 a,c). In young specimens, the anal
aperture is proportionately smaller.

The base is concave, and the mouth central, and placed im a considerable depression.
It is of moderate size, about one fifth the diameter of the test ; the peristome is nearly
equally decagonal, the ambulacral being larger than the inter-ambulacral lobes; the
notches are wide, and the margin is everted (fig. 1 4). Although I have searched diligently
for the teeth, I have never yet seen a vestige of one, although there cannot be a doubt
that the Pygasters possessed jaws like those of Holectypus depressus, Leske.

The spines adhering to the fine specimen I have figured are short and needle- shaped;
and delicately striated longitudinally.

Affinities and differences.—Pygaster semisulcatus resembles in many points Pygaster
umbrella, Agassiz, but is distinguished from that urchin by the following characters:
The tubercles, especially those on the upper surface, are disposed in much more regular

278 PYGASTER.

horizontal and vertical rows, the ambulacral areas are not so lanceolate, the anal
opening is wider in the upper part, and does not descend so far down the inter-ambulacrum
as in P. umbrella, in which it has.a well-marked pyriform shape, and is much contracted

in the upper part like a key-hole. (Compare Pl. XIX, fig. 1, with Pl. XX, fig. 2.)

Locality and Stratigraphical position—This species has been collected from the
Pea-grit, Inferior Oolite of Crickley, Birdlip, Shurdington, Leckhampton, Cleeve, and
Sudeley Hills, Gloucestershire, where it is abundant, although good specimens are rare.
I possess a series of all sizes, from half an inch to three inches and a half in diameter.
It is found likewise in the shelly freestone at Leckhampton, and I have extracted small
specimens from the planking beds: of the Great Oolite at Minchinhampton Common. In
Yorkshire it is collected only from the Inferior (Great?) Oolite at Whitwell. In the
Pea-grit at Crickley Hill it is associated with Ammonites Murchisone, Sow., Nautilus
truncatus, Sow., Terebratula simpler, Buck, Terebratula plicata, Buck; and Thecidium
triangulare, WOrbig., is often adherent to its test. Pseudodiadema depressum, Agas.,
Hyboclypus agariciformis, Korb., Cidaris Fowlert, Wright, Cidaris Bouchardii, Wright,
and Acrosalema Lycetti, Wright, are its usual associates.

PycasTer conorpEus, Wright. Pl. XIX, fig. 2a, 6, c,d, e, f.

PYGASTER CONOIDEUS. Wright, Annals and Magazine of Natural History, 2d series, vol. ix,
p- 91, pl. 3, fig. 1.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 88.
— — Salter, Memoirs of the Geological Survey, Decade V, pl. 8.
— a Desor, Synopsis des Echinides Fossiles, p. 166.

Test pyramidal, pentahedral; posterior border sub-acute; ambulacral areas narrow
and prominent, with two rows of small marginal tubercles, and two imperfect, incomplete
rows within; inter-ambulacral areas upwards of four times the width of the ambulacral ;
tubercles of both areas very small, and scattered without much order on the surface
of the plates, which are covered with minute spaced-out granules; vent small, occupying
rather more than the upper third of the single inter-ambulacrum; marginal fold acute,
sides of the pentahedron rising abruptly therefrom; base flat, mostly concealed
by the matrix.

Dimensions.—Height, one inch and three tenths; antero-posterior diameter, twe
inches and nine twentieths ; transverse diameter, two inches and four tenths.

Description.—This very rare Pygaster is remarkable for its pyramidal form; the

FROM THE INFERIOR OOLITE. 279

sides, which are pentahedral, rise abruptly from the marginal fold; the anterior and
lateral pairs of inter-ambulacra form angles of from 50° to 55° with the base, and the
single inter-ambulacrum makes an angle of about 42° (fig. 2 a). The ambulacral areas
are narrow and prominent, and placed nearly equidistant from each other; the single
anterior area is straight; the anterior pair curve forwards, upwards, and backwards; the
posterior pair rise forwards and upwards for three parts of their course, then curve
inwards towards the anal opening, and terminate near the posterior part of the disc
(fig. 2a). There are two complete rows of tubercles extending from the peristome to
the disc, arranged on the margins of the areas, a primary tubercle being developed on every
third plate (fig. 2 7); two inner rows commence near the mouth, pass round the angle,
and rise half way up the sides, but the tubercles thereof are smaller, less regular in their
arrangement, and more incomplete than the marginal rows; like them, however, one
tubercle rises from every third plate; at the widest part of the areas, near the border,
a few tubercles form a fifth row of very limited length (fig. 2 4).

The poriferous zones are narrow, and sunk in slight depressions (fig. 2¢); the pores
are strictly unigeminal throughout; the pores are nearly equal, and the septa develop
a small ridge between them (fig. 2 ¢); one pair of pores corresponds to a pair of ambulacral
plates; as there are thirty marginal tubercles on the upper surface of one area, and every
third plate supports one tubercle, it follows that there are ninety pairs of pores in the
poriferous zones on the upper surface alone; as the areas are only partially exposed at the
base, the pores cannot be counted in that region.

The inter-ambulacral areas are more than four times as wide as the ambulacral; there
are eighteen pairs of plates in each area, between the margin and the disc; each plate is
bent in the middle (fig. 2 @), and supports numerous small tubercles, their number on the
plates varying according to their length; they are disposed in single transverse rows on
the centro-sutural half, and in double rows on the zonal half of the plates; near the
margin, there are four tubercles in the single row, and three pairs of tubercles in the
double rows, but on the shorter plates they are much fewer and less regular (fig. 2 ¢).
On the under surface the tubercles are larger, and arranged in concentric rows; there are
from six to eight tubercles on each plate, the smooth areolas of which nearly touch (fig. 2 4).

The tubercles on the upper surface of this species are extremely small, and form a
remarkable contrast to those in the same region of the test in Pygaster semisulcatus ; their
arealas are scarcely sunk, and the granulations on the surface of the plates are very small,
and placed rather widely apart (figs. 2 a, ¢, e).

The single inter-ambulacrum is concave between the disc and the border, and the anal
opening occupies its upper third (fig. 2 e); this aperture is of the same shape, but smaller
than in P. semisulcatus (fig. 2 a); the portion of the area below the vent is flattened, and
the tumid ridges are absent.

The base is partly concealed by firmly adhering matrix, which cannot be removed
without the risk of splintering the test; enough, however, is exposed, to show that

280 PYGASTER.

the base is slightly concave, and that the tubercles im that region are larger than those
on the upper surface (figs. 2 6 and /).

Afinities and differences.—This species resembles P. semisulcatus in its pentagonal
form, but it is pyramidal and pentahedral, and is neither hemispherical nor depressed ; it is
distinguished from that species by a greater prominence of the ambulacra, the smallness
of the tubercles, the superficiality of the areolas, the microscopic character of the granules,
and the smallness of the vent. It is a very rare species, as I have only seen a specimen
in Mr. Lycett’s cabinet, besides the one now figured in detail.

Locality and Stratigraphical position—I collected this urchin from the Pea-grit
at Crickley Hill. Mr. Lycett’s specimen was found in the lower beds of the Inferior
Oolite, near Stroud.

B. Species from the Cornbrash = 11° Htage Bathonien, d’Orbigny.

Pycaster Morrisu, Wright. Pl. XX, fig. 1 a, 6, ¢, & e,f.

Pycaster Morris. Wright, Annals and Magazine of Natural History, 2d ser., vol. ix,
p. 92, pl. 4, fig. 1.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d edit., p. 88.
— — Wright, Memoirs of the Geological Survey, Decade V. Notes on
British species of Pygasters.
— — Desor, Synopsis des Hchinides Fossiles, p- 166.

Test pentagonal, depressed; marginal fold very tumid; single inter-ambulacrum
much truncated; ambulacral areas wide, convex, and prominent, with six rows of
tubercles; inter-ambulacral areas wide, with rather large tubercles, in very regular
vertical and horizontal rows, from twenty to twenty-two im each space on the same
horizontal line at the equator; base flat, concave towards the mouth opening, which is
small; anal opening long, pyramidal, occupying two thirds of the upper surface of the

inter-ambulacrum.

Dimensions.— Height, eight tenths of an inch; antero-posterior diameter, two inches
and three twentieths of an inch; transverse diameter, two inches and a quarter of

an inch,

Description.—This is one of our rarest Pygasters, and the specimen figured is the
only one I know. It has a thick test, with a very pentagonal outline, is much depressed
on the dorsal surface, has a flat base, tumid sides, is remarkable for the size of its tubercles,
and for the regularity of their arrangement in vertical and horizontal rows.

FROM 'THE CORNBRASH. 281

The ambulacral areas are wide, convex, and prominent, and form an exception to
the generalisation of M. Agassiz, that in the genus Pygaster the ambulacra are furnished
with only four rows of tubercles, for in this species at the widest part of the area there
are six rows of well-developed tubercles (fig. 1 a, 4); the two marginal rows, with about
forty-five tubercles in each row, extend from the peristome to the disc; the second rows
commence at a short distance from the moutk, and extend two thirds of the length of
the upper surface; the third rows commence at the base, about half an inch from the
border, and extend to about the same distance up the sides of the area (fig. 1 4).

The poriferous zones are straight, the pores have moderately thin septa, with only
slight elevations on the surface, and there are four pairs of pores opposite each inter-
ambulacral plate (fig. 1 d).

The inter-ambulacral area$ are three times the width of the ambulacral; at the
circumference they are furnished with twenty-two rows of tubercles, which attain a
greater size and are arranged with more regularity than in any other English species ;
each plate above the circumference has from eight to nine tubercles developed on its
surface (fig. 1 d); those on the half of the plate nearest the centro-suture are arranged
horizontally on the same line, whilst the tubercles nearest the zones form double rows in
oblique pairs. ‘The tubercles are raised on prominent bosses, and surrounded by wide,
sharply defined, sunken areolas (fig. 1 d) ; each areola is surrounded by a circle of granules
(fig. 1 e); there are thirty-six pairs of plates in each area, twenty-one of which are dorsal
and fifteen are basal. ‘The tubercles attain their greatest development at the base, where
they are so uniformly arranged, and so closely set together, that they appear to arise from
hexagonal spaces (fig. 1 4) ; the areolas are deeply excavated (fig. 1 7), and have a square
or hexagonal figure, two sides bemg bounded by granules, the other two by sharp
elevations of the areolar border (fig. 1 /); of the twenty-two rows of tubercles which
occupy the area at the circumference, only six, and these the three central rows of each
column, extend from the peristome to the disc, the others disappear at shorter distances,
the length of the rows being in proportion to their distance from the margin of the columns.

Although the upper surface of this urchin is much depressed, its sides are tumid, as is
well seen in the profile (fig. 1 ¢). The single inter-ambulacrum is much truncated
(fig. 1 a), and the large anal opening, which has an oblong shape, occupies the upper
three fourths of this area ; the discal opening is small, and the plates are all absent.

The marginal angle is obtuse, the outer half of the base is convex, and the mner half
concave; the small mouth opening, which is about one sixth the diameter of the test, lies
in a deep depression.

The spines are short, stout, needle-shaped bodies, marked with fine longitudinal

lines.

Affinities and differences.—This species resembles P. laganoides, Agassiz, in its
depressed form, obtuse basal angle, and truncated single inter-ambulacrum ; but

282 PYGASTER.

P. Morrisii has a greater number of tubercles in the ambulacral and inter-ambulacral
areas, P. laganoides having four rows in the ambulacral and fourteen in the inter-
ambulacral areas, whilst P. A/orrisii in the same region of the corresponding area possesses
six rows and twenty-two rows.

P. Morrisui resembles P. Gressly, Desor, in its general form, in the size and dis-
position of its tubercles, and in their surrounding granulation, but P. Morristi is more
depressed, has a larger anal opening, and more rows of tubercles in both areas.

Locality and Stratigraphical position—tThis rare species was collected by Mr. W. Buy
from the Forest Marble or Cornbrash near Stanton, Wilts. The specimen figured
(Pl. XX, fig. 1) is the only one I know. I have seen a Pygaster from the Great Oolite
near Cirencester, which resembles my urchin; but the specimen was crushed, and not
otherwise determinable ; it had the same number of tubercles in the areas as P. Morrisii.
I dedicate this species to my friend Professor John Morris, to whose valuable labours
British paleeontologists are under so many lasting obligations.

C. Species from the Coral Rag = 14° Etage Corallien, d’Orbigny.

PYGASTER UMBRELLA, Agassiz. Pl. XX, fig. 2 a, 6, ¢, d, e, f.

PYGASTER UMBRELLA. Agassiz and Desor, Catalogue raisonné, Ann. des. Scienc. Nat.,
. 3° série, tom. vii, p. 144, 1847.

a — Bronn, Index paleontologicus, Bandi, p. 1066, 1848.

— — D’Orbigny, Prodrome de Paléontologie, tom. i, 13° étage,
No. 510.

— Epwarpsgvus. Buvignier, Statistique geologique, paléontologique depart. de la
Meuse Atlas, p. 46, pl. 32, figs. 31—33, 1852.

— UMBRELLA. Wright, Memoirs of the Geological Survey, Decade V, pl. 8.
Note on British Pygasters, 1856.

— — Cotteau, Etudes sur les Echinides Foss., p. 194, pls. 27, 28, fig. 1,
1856.

— — Desor, Synopsis des Echinides Fossiles, p. 165, 1857.

Test large, more or less elevated, sometimes circular, oftener sub-pentagonal ; ambu-
lacral areas narrow, with two complete marginal rows of tubercles, and two imcom-
plete rows, which commence near the peristome, and extend only half way up the
sides ; inter-ambulacral areas wide, with from sixteen to eighteen rows of tubercles at the
equator, which are small and rather irregularly disposed on the upper surface, but
large and arranged in regular horizontal and vertical series at the circumference and
base ; anal opening distinctly pyriform, occupying rather more than one half the length

FROM THE CORAL RAG. 283

of the upper surface of the single inter-ambulacrum; base concave; mouth opening
small, peristome equally decagonal, apical disc large, composed of unequal-sized genital
plates; the right antero-lateral very large, and extending backwards beyond the centre ;
ocular plates small, eye-holes marginal.

Dimensions.—In the following table I have given the dimensions of four English
specimens from different localities enumerated in this article, and have added the measure-
ments of M. Cotteau’s urchin from Chatel-Censoir.

Height. Deg | Antero-posterior | Length of discal and |
iameter. ~ diameter. anal opening.
Pygaster umbrella, Agass. |
Inches. Inches. Inches. Inches. |
;
Specimen from Malton . : 2 4f 435 lt
oe », Headington : = 45 | 45\5 | indeterminable
rE » Lyneham k 15 3 249 | 135
35 », Farringdon : 1x 2-8, 255 | 155
a3 » Malton . ‘ 1 245 2-6 1+
e » Chatel-Censoir 1,55 3-85 | 355 12
|

Description.—The greatest confusion exists regarding the synonyms of this species.
MM. Agassiz, Desor, and Cotteau, who have each figured and described this urchin, cite
Galerites umbrella, Lam., as its type; now, Lamarck * does not say that he had seen the
fossil, but refers to “‘ Leske apud Klein, p. 157, t. 12, and ‘ Encycl. Méthod.,’ pl. 142,
figs. 7, 8,” as the species intended. After consulting the original figure in Klein, which re-
presents Clypeus sinuatus, Leske, in the Dresden Museum, I do not see how sucha
reference can be sustained, as the CZypeus in question belongs not only to a different
genus, but even to a distinct family of the Echinoidea. As Deslongchamps,t Defrance,{
De Blainville,§ and Desmoulins|| all founded their synonyms on this mistake, I have not
cited these authors in my list, for the obvious reason, that their references were made
under an erroneous impression. It is strange that MM. Agassiz and Desor, when cor-
recting the synonyms of the Pygasters, in their ‘ Catalogue raisonné,’ should not have de-

* Galerites umbrella, Lamarck, ‘Animaux sans Vertébres,’ tom. iii, p. 23, 1816.

+ Galerites umbrella. Deslongchamps, ‘Encyclopédie méthodique Hist. Nat. des Zoophytes,’ tom. ii,
p. 434.

t Nucleolites umbrella. Defrance, ‘ Dict. des Sciences Naturelles,’ art. Galérites, tom. xviii, p. 87, 1825.

§ Echinoclypeus umbrella. Blainville, ‘ Dict. des Sciences Naturelles,’ art. Zoophytes, tom. ix, p. 189,
1830.

|| Nueleolites umbrella. Desmoulins, ‘ Etudes sur les Echinides,’ p. 354, No. 2, 1837.

37

284 PYGASTER.

tected this primary error; so true is it, that unless we compare typical specimens with
each other, the highest authorities may be misled by imperfect figures.

In the ‘ Echinodermes Foss. de la Suisse,’ M. Agassiz™ figured as Pygaster umbrella, an
urchin found by M. Gressly in “le Portlandien du Jura Soleurois.” This figure was
reproduced by M. Desor,t in his ‘Monographie des Galérites.’ In the ‘Catalogue
raisonné, however, these authors have changed the name of the Swiss urchin to P.
dilatatus, and have given that of P. wmbrella to a species from the Coral Rag of Chatel-
Censoir (Yonne).

In the “Etudes sur les Echinides Foss. du département de l’Yonne,’ M. Cotteau
has given for the first time good figures with details, and a description of this species ;
and he has likewise kindly sent me type specimens thereof, so that I have ample materials
for comparing our specimens with P. umbrella, Agassiz (1847). Unfortunately M. Cotteau’s
figured specimen is partly denuded of its shell, and my specimen is only an interior
mould, but the general form of the test, and the figure of the vent opening, are well
preserved.

The test of Pygaster umbrella is thick; in some specimens it has nearly a circular, in
others a sub-pentagonal, form; in some the upper surface is moderately convex (fig. 2 c),
in others it is more or less depressed; in fact, its general outline varies much with age,
sex, and external conditions, so that it is difficult to give a general description of its form
that will be true for three or four specimens from different localities.

The test (fig. 2 a, c) was kindly given me by my friend Mr. J. G. Lowe; it exhibits the
var. a, with a circular outline, and is selected in consequence of the fine preservation of
the shell on its upper surface. ‘The ambulacral areas are narrow and lanceolate
(fig. 2 a), the single area and the anterior pair are straight, and the posterior pair are
only slightly curved inwards at their upper part. They have two marginal rows of
tubercles, which extend uninterruptedly from the peristome to the disc, there are thirty
tubercles on each row between the margin and the apex, and from eighteen to twenty at
the base; midway between the peristome and the margin two inner rows of tubercles
commence, which extend only one third the distance up the sides, and at the widest part
of the areas a few additional tubercles forming a fifth row exist (fig. 2d). As the
marginal tubercles are developed on every third plate, it follows that there are 48 x 38 = 144
plates in each area. The poriferous zones are narrow (fig. 2 d), one pair of pores corre-
sponding to one ambulacral plate; the septa are narrow, and slightly elevated on the
surface; and there are from six to seven pairs of pores opposite each inter-ambulacral
plate (fig. 2 d).

* Pygaster umbrella. Agassiz, ‘ Description des Echinodermes Fossiles de Ja Suisse,’ 1" partie, p. 8,
tab. 12, figs. 4—6, 1839.

Pygaster umbrella. Agassiz, ‘Catalogus Systematicus Ectyporum Echinodermatum Fossilium,’
p- 7, 1840.

+ Pygaster umbrella. Desor, ‘ Monographie des Galérites,’ p. 77, tab. 12, figs. 4—6, 1842.

FROM THE CORAL RAG. 285

The inter-ambulacral areas are four times as wide as the ambulacral; there are about
thirty-two pairs of plates in each column, of which eighteen belong to the upper surface,
and fourteen to the base; the plates are bent in the middle, and at the widest part of
the area, each plate supports seven tubercles; the four nearest the zones are arranged in
oblique pairs, and the three nearest the centro-suture in horizontal lines (fig. 2 d); at
the margin there are from eighteen to twenty tubercles in one horizontal series.

The tubercles on the upper surface are small (fig. 2a); they have slightly sunken
areolas, and are raised upon small bosses with smooth summits (fig. 2.7); the areolas are
surrounded by six small granules (fig. 27), and others are scattered sparingly -on the
surface of the plates; these granules, like the tubercles, are all perforated (fig. 2d).

The tubercles at the base are much larger (fig. 2 4), and they are arranged in close-
set, horizontal lines; the areolas are more excavated, and rather square-shaped; they are
bounded by a single row of granules (fig. 2 g); and the tubercles of both areas are about
the same size.

The base is concave, slightly so at the sides, but much depressed at the centre; the
mouth opening is small, and the peristome is equally decagonal. “Its circumference is
armed with ten prominent carinze, which, in the interior moulds, have left on the borders
of the inter-ambulacral areas very apparent imprints.” * These carinze, which M. Desort
had already observed in a specimen of Pygaster costellatus, are doubtless destined in
the Pygasters to replace the auricles of the Croarrp# and Ciyprastertpa. M. Michelint
has recently discovered m a Pygaster umbrella a masticating apparatus, which resembles
that of a Clypeaster, the united pieces of which form a very acute pyramid.

The anal opening is very large, and occupies more than the upper half of the single
inter-ambulacrum (fig. 2 a); it has a pyriform figure, contracted above and swelling out
below, which, with the discal space, produces a keyhole-like opening in the test. In most
of the specimens this aperture is not symmetrical, and bulges more to the left than to the
right side; in fig. 2 @ a portion of the test is broken, which gives the vent in this specimen
a more symmetrical form than in all the others I have examined (fig. 2 c).

The greater portion of the apical disc is preserved in one of the specimens from Malton,
kindly given me by Dr. Murray (fig. 2 4, e) ; the genital plates have an irregular rhomboidal
form, with pointed apices, and perforations for the canals near the apex; the right antero-
lateral plate is disproportionately large, and the shield-like madreporiform body extends back-
wards into the centre of the disc (fig. 2 e); the ocular plates are small triangular bodies
wedged into the angles formed by the genitals; the eye-holes are marginal and lodged in a
depression between the plate and the apex of the ambulacral area (fig. 2 e); the surface of

* Cotteau, ‘ Etudes sur les Echinides Foss.,” jon US Ree

+ ‘Monogr. des Galerites,’ p. 76. :

{ Hardouin Michelin, Déscription de quelques nouvelles espéces d’Echinodermes fossiles, ‘ Revue et
Magasin de Zoologie,’ 2° série, tom. v, p. 36, 1853.

286 PYGASTER.

all the disc plates is covered with numerous small granules; and still smaller granules are
scattered over the surface of the madreporiform body (fig. 2 e).

Affinities and differences.—This species very much resembles Pygaster semisulcatus,
Phil., and was for a long time mistaken for that species; Professor Phillips having stated
that P. semisulcatus was common to the Great (?) Oolite of Whitwell and the Coralline
Oolite of Malton; this, however, I have proved, by an examination of the specimens, to be
an error, the Malton Pygasters being quite distinct from the Whitwell species.

In P. umbrella the tubercles on the upper surface are always smaller, and not very
regularly arranged in vertical and horizontal rows; the bosses are less elevated, the
areolas less defined, and the intervening granules smaller and fewer in number than in
P. semisulcatus. The discal opening is smaller; the anal opening is longer, more
pyramidal, and seldom symmetrical, occupying sometimes two thirds of the area; the basal
tubercles of both species are nearly alike in size; in P. umbrella, however, there is a much
greater disproportion between the size of the tubercles on the upper and under surfaces of
the test than exists in P. semisulcatus.

P. umbrella is easily distinguished from P. Morrisii by the size of the tubercles in the
latter, its more decided pentagonal form, larger ambulacra, and tumid sides.

P. dilatatus, as stated by MM. Agassiz and Desor, “Se distingue du P. wmérella par
son bord plus tranchant et sa forme plus dilatée.’ The shape of the anal opening is
different, and it wants the pyramidal figure so characteristic of P. umbrella ; it belongs
likewise to a different stratigraphical horizon, having been collected from the “ Portlandien
du Jura Soleurois, carriére de Greifel (vallée de la Birse) ;” whilst P. wmérel/a is found
only in the Coral Rag.

Locality and Stratigraphical position.—1 have collected this urchin from the lower
calcareous grit at Headington, near Oxford; from the Coralline Oolite of Malton,
Yorkshire; from the Coral Rag near Farringdon, Berks; and from the Coral Rag of
Lyneham and Calne, Wilts; in the two latter localities it was associated with Czdaris
florigemma, Pseudodiadema versipora, P. mamillanum, and Echinobrissus scutatus—all true
Corallian forms.

On the Continent it has been collected by M. Cotteau from the ‘‘ Calcareo-siliceuses des
environs de Druyes, 4 Chatel-Censoir, et 4 Montillot (Yonne) ;” by M. Buvignier from the
Coral Rag environs of Saint Mihiel (Meuse) ; and M. Seemann, of Paris, kindly sent mea
specimen which was obtained from the Coral Rag of Commercey (Meuse).

287

NOTES

On Fornricn JURASSIC SPECIES OF THE GENUS PYGASTER NEARLY ALLIED TO

BRITISH FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLIsH Oo.itEs.

PYGASTER LAGANOIDES, Agassiz. Echinoderm. Foss. Suisse, tabl. 12, figs. 13—16.
Desor. Monogr. des Galérites, tabl. 11, figs. 5—7.

Test sub-circular, depressed ; four rows of tubercles in the ambulacra, which are one
third the width of the inter-ambulacra; twelve rows of tubercles in the inter-ambulacra ;
the tubercles are large, and nearly all of the same size; base concave, mouth opening large,
peristome feebly notched ; anal opening large, of an elongated form, and occupying nearly
two thirds of the single inter-ambulacrum.

Dimensions.—Height, six tenths of an inch; transverse diameter, one inch and six
tenths ; antero-posterior diameter, one inch and a half.

Formation.—Bathonien, “ Calcaire 4 polypiers de Ranville,’” Normandy.

Collections. —Deslongchamps, Michelin, @’Orbigny ; my cabinet.

Pycaster Gressty1, Desor. Monogr. des Galérites, p. 80. Synopsis des Echinides
5 Foss., tabl. 22, figs. 1, 2.
Cotteau. Etudes sur les Echinides Foss., pl. 28, figs. 2—6.

Test thin, small, sub-pentagonal, depressed ; inflated at the sides, flat at the base,
ambulacra with four rows, inter-ambulacra with twelve rows of tubercles at the
circumference; the tubercles are large, equal-sized, and surrounded by granules; anal
opening pyriform, contracted near the disc; base concave, mouth opening moderate in
size, peristome deeply notched ; tubercles at the base surrounded by hexagonal areolas.

288 FOREIGN JURASSIC PYGASTERS.

Dimensions.—Height, six tenths of an inch ; transverse diameter, one inch and a half;
antero-posterior diameter, nearly one inch and a half.

Formation.—Corallien, “‘ Couches supérieures de étage corallien, et recueillis dans les
carriéres de Vauligny pres Tonnerre (Yonne).” Cotteauw. “Dans un
banc a coraux du Portlandien, a Reedersdorf (Haut-Rhin).” Agassiz.

Collections —M. Rathier, M. Vabbé Bellard, M. Gressly, M. Cotteau. Rare.

PYGASTER PATELLIFORMIS, Agassiz. Echinoderm. Foss. Suisse, tabl. 13, figs. 1—3.
Desor. Monog. des Galérites, tabl. 11, figs. 11—13.

Test thick, hemispherical, more or less depressed; circumference sub-pentagonal ;
tubercles large, equal-sized, and arranged in regular rows; ambulacra with four rows of
tubercles; inter-ambulacra four times the width of the ambulacra, with fourteen rows of
tubercles ; all the tubercles surrounded by small granules; anal opening large, pyriform,
contracted above, wide below, occupying two thirds the length of the area; mouth
opening large, peristome deeply notched.

Dimensions.—Height, one inch and a quarter; transverse and antero-posterior diame-
ters, three inches.

Formation.—< Kimmeridge de Lauffon dans la vallée de la Birse (Berne).” Agassiz.

Collections. —Museum of Neuchatel, M. Gressly. Very rare.

PyGastTER DILATATUS, Agassiz. Syn. Pygaster umbrella, Agassiz. Echinoderm. Foss.
Suisse, part. 1°, tabl. 13, figs. 4—6.
Pygaster umbrella, Desor. Monogr. des Galérites,
tabl. 12, figs. 4—6.

This is the urchin which was described by MM. Agassiz and Desor in their respective
works as the type of Pygaster umbrella. In their ‘ Catalogue raisonné,’ however, it is
separated from P. wmbrella of the Coral Rag, under the name P. dilatatus, with this
remark—“ Se distingue du P. wmérella par son bord plus tranchant et sa forme plus
dilatée.” The original specimen is an interior mould; M. Gressly has, however, found one
with a portion of the test preserved. The fragment of the test is very thick, and has large
tubercles, disposed nearly as in P. patelliformis. The general form of the mould, and

FOREIGN JURASSIC PYGASTERS. 289

the shape of the anal opening, which is pyriform, likewise resemble that species. M.
Desor, in his ‘Synopsis,’ remarks—*“ Grande espéce subpentagonale, étalée, 4 bord plus
aminci que dans aucune autre espéce.” It is probable that P. patelliformis and
P. dilatatus may be different conditions of the same species, as they are both Kimmeridge
forms.

Dimensions.—Height, two inches ; transverse diameter, four inches and a half.

Formation.—“ Kimmeridge du Jura Soleurois, carriére de Greifel, vallée de la Birse
Canton de Berne.” Agassiz. Very rare.

Collection. —M. Gressly.

Pycasrer PrLEus, Agassiz. Syn. Pygaster pileus, Cotteau. Etudes sur les Echinides
Foss., pls. 29 and 30.
Pileus hemisphericus, Desor. Syn. Echinod. Foss.,
tabl. 22, fig. 6.

Test large, sub-pentagonal; upper surface sub-conical; base flat or sub-concave ;
ambulacra convex and prominent, with six rows of small, irregularly disposed tubercles ;
inter-ambulacra wide, with numerous small tubercles disposed partly in single, and
partly in double, horizontal rows; middle of the areas depressed, and deprived of
tubercles; anal opening pyriform, situated in the lower half of the single inter-
-ambulacrum; between the apex of the vent and apical disc the test is entire, so that
a large triangular space exists in this species, filled with the plates of the test, not found
in other Pygasters, m all of which, with this exception, the discal opening and vent
conjoin; mouth small, situated in a deep depression in the centre of the under surface.

Dimensions.—Height, one inch and three quarters; transverse and antero-posterior
diameters, four inches.

Formation.—* Coral-rag inférieur; dans les couches blanches et pisolithiques de
Coulanges-sur-Yonne et de Chatel-Censoir; calcaire a chailles de

Druyes.” Cotteau.

Collections —Muséum @histoire naturelle de Paris, M. Salomon, M. Cotteau. Very
rare. Plaster mould in my cabinet.

In consequence of this Pygaster having the anal opening in the lower part of the
inter-ambulacrum, and a considerable portion: of the test between its apex and the disc,
M. Desor has erected it into a new genus, under the name Pileus hemisphericus.

290 FOREIGN JURASSIC PYGASTERS.

Pyeaster mMacrocypuus, Wright, nov. sp. Davidson’s MSS., pl. 2, figs. 1, 2, 3.

Test thick, large, sub-pentagonal ; upper surface convex, or more or less depressed ;
base concave; ambulacra narrow, with two irregular rows of small marginal tubercles, and
two short rows, equally irregular, internal to them, which disappear from the upper
two thirds of the areas ; inter-ambulacra five times the width of the ambulacra; each of
the plates near the border supports about seven unequal-sized tubercles ; those repre-
senting the primary rows are larger than the others; the tubercles, however, are in
general large, and very irregularly disposed; the inter-tubercular surface of the plates is
covered with an abundance of miliary granules; the bosses of the tubercles are prominent,
and surrounded by ring-like areolas, and the granules form circles around each; there is
a median depression in the centre of the upper part of the areas; the anal opening is
small in proportion to the size of the urchin, and occupies nearly the upper two thirds of
the area; it appears to have had a pyriform shape, much of the upper surface of the test
is broken in my specimen, so that its precise form is indeterminable; base concave ;
mouth opening small, one sixth the diameter of the test; peristome deeply notched,

lobes equal.

Dimensions.—Height, one inch and a half; transverse diameter, four inches and a
half.

Formation—Kimmeridge clay, from a cliff between Boulogne-sur-Mer and Portel.
Very rare; I only know two specimens.

Collections.—Thomas Davidson, Esq., F.R.S. The specimen in my collection was
found by M. Bouchard-Chantereaux in the same rock and locality,
and was generously given me by that gentleman for this work.

Pycaster TENUIS, Agassiz. Hchinoderm. Foss. Suisse, p. 83.
Desor. Monogr. des Galérites, tabl. 12, figs. 1—3.

“A very large, sub-pentagonal, depressed species, with small and numerous tubercles,
twenty rows in the inter-ambulacral areas, and six in the ambulacral areas, which are not
very regular. This species is distinguished by its very thin test.

“< Formation.—Corallien inférieur (Terrain a chailles) de Fringeli, Canton de Soleure.

“ Collection.—M. Gressly. Very rare.” Desor.

291

Genus—HYBOCLYPUS. 1839.

The urchins grouped in this genus present an assemblage of characters which belong to
so many distinct forms of Ecurnoipna, that they may probably hereafter be found to
constitute a separate family, rather than a section of the Ecurnoconrpa, with which they
are now provisionally placed for want of sufficient materials to justify such a separation.

Their test is thin, and in general as wide as it is long; the anterior half is more
elevated than the posterior half, and sometimes rises into a prominent ridge. The surface
of the plates is covered with numerous concentric rows of small perforated tubercles,
set close together, and raised on low crenulated bosses, which are encircled by sunken
areolas, and the intermediate surface is crowded with microscopic miliary granules.

‘he ambulacral areas are narrow, flexuous, and disjointed at the summit by the
length of the apical disc. ‘The three anterior areas terminate at the front of the disc,
and the posterior pair at some distance behind them. The single area is lodged in a
depression of the anterior border.

The poriferous zones are very contracted ; the pores are simple and unigeminal; they
are placed close together on the upper surface, and wide apart at the base.

The inter-ambulacral areas are very wide; the single inter-ambulacrum is traversed
superiorly by a deep longitudinal valley, which commences behind the apical disc; in the
upper part of this channel the wide vent opens on the dorsal region.

The apical disc is central, but not vertical; it is narrow and elongated, in consequence
of the length and singular disposition of its component elements; the anterior pair of
ovarial plates are shield-shaped; the right plate is the largest, and supports the madre-
poriform body; the posterior pair are much larger and longer than the anterior pair,
and both pairs are perforated; the single ovarial plate is composed of two or more long,
narrow, imperforate pieces, placed end to end in the centre of the disc; the single ocular
plate is small; the anterior pair are large, and disposed side by side in a line in the
middle of the disc, de¢ween the anterior and posterior ovarials, instead of being lodged in
angles formed éy them; the posterior pair of oculars are situated at the end of the
posterior ovarials (Pl. XXI, fig. 2 ¢), and thereby give lengthened extension to the disc.

I have discovered this singular arrangement of the discal elements in three different
species, and now regard it as a valuable generic character (Pl. XX, fig. 2e; Pl. XXII,
fig. 1 e, and fig. 2 2).

The small mouth opening, in general, is situated near the anterior third of the base,
which in some species is concave, and much undulated; the peristome is sub-pentagonal
or elongated in the antero-posterior diameter.

The Hyboclypi, like other Ecutnoconipa, have simple poriferous zones, perforated

38

292 HYBOCLYPUS.

and crenulated tubercles, and manifest a disposition to a conical elevation of the upper
surface of the test; they are unlike the true type forms of this family, however, in the
excentral position of the mouth, the absence of notches from the peristome, in the
possession of a longitudinal dorsal valley, and in having the opening of the vent therein ;
the elongation of the apical disc, the singular disposition of its elements, and the disjunc-
tion of the posterior pair from the three anterior ambulacra, which converge around the
front of the disc, form a group of negative characters that sufficiently justify our doubts
as to the propriety of placing this genus in the family Ecu1noconipz.

The Hyboclypi resemble in some respects the CoLLyRiITIDA, in possessing an elongated
apical disc, and having two ambulacral summits, consequent on the disjunction of the
anterior from the posterior pair of ambulacra. They have affinities with the Ecu1nopris-
s1D# in having the test contracted before and expanded behind, the mouth small and
excentral, and the vent opening into a longitudinal valley on the dorsal surface; but in
the structure of the tubercles, the apical disc, and poriferous zones, they are very different
from all the forms of that family.

The Hyboclypi form an aberrant type of the Ecn1norp2a, having close affinities with the
Ecuinoconip# on the one side, and the Cottyritip# on the other; they appear to form
a transition link between these twa families, and are probably entitled to rank as a separate
sub-family.* Our imperfect knowledge of the mtimate structure of the mouth, and the
presence or absence of jaws in these urchins, make it uncertain how far this separation
would be justified by anatomical characters, concealed or unknown.

The different species of this genus have hitherto been only found in the Oolitic rocks ;
they had their greatest development in the lower division of that series, as all the English
species are found chiefly in the Inferior Oolite.

A. Species from the Inferior Ookte.

Hyzociypus acaricirormis, Forbes. Pl. XXI, fig. la, 6, ¢, d, e, fi g.

PYGASTER SUBLEVIS ? M‘Coy, Aunals and Magazine of Natural History, 2d series,
vol. ii, p. 413.
HyYBOCcLYPUS AGARICIFORMIS. Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 99.
ox — Forbes, Memoirs of the Geological Survey, Decade V, pl. 4.

* The genus Hyboclypus is placed by M. Desor, in his ‘Synopsis des Echinides Fossiles,’ p. 192, in
his 2d type of the family Galeridées—‘‘ Genres a appareil apicial alongé, sans plaque génitale impaire.”
I have already shown that the Hybdoclypi not only possess a single imperforate ovarial plate, but that it is
composed of two or more pieces. I must therefore regard M. Desor’s definition as a mistake, which has
probably arisen from the imperfect condition of the disc in the specimens he examined.

FROM THE INFERIOR OOLITE. 293

HYBOCLYFUS AGARICIFORMIS. Forbes, in Morris’s Catalogue of British Fossils, 2d edition,

p. 82.
NUCLEOLITES DECOLLATUS. Quenstedt, Handbuch der Petrefactenkunde, tab. 50,
fig. 6, p. 585.

GALEOPYGUS AGARICIFORMIS. Cotteau, Mém. lu 4 la Soc. Géol. de France, le Juin, 1856.
— _ Desor, Synopsis des Echinides Fossiles, p. 167.

Test in general disciform, sometimes convex or conical, with a pentagonal circum-
ference ; ambulacral areas narrow, the three anterior straight, the posterior pair sinuous ;
inter-ambulacral areas wide, unequal, the plates covered with a great number of microscopic
tubercles; apical disc small, central, and vertical; anal valley deep, with parallel sides,
which gradually expand about the middle of the single inter-ambulacrum; mouth opening
small, sub-central, nearer the anterior border; peristome feebly decagonal; poriferous
zones narrow, pores unigeminal in the upper surface, at the base wide apart and
trigeminal.

Dimensions.—The measurements given in the following table are made from four
specimens which represent the four varieties this species assumes.

7 Transverse Antero-posterior
Height. diameter. diameter.
No. Hyloclypus agariciformis, Forbes.
Inches. Inches. Inches.
1 Disciform var. a - : : 05 32 356
2 Type var. ie - . : 1 23,5 23
3 Convex var. yv j : : 1 255 2545
4 Conical var. 54 5 3 7 135 235 235

Description—In the above table I have given the measurements of four specimens of
this urchin, with the view of showing the diversity which exists in the relative proportions
of different forms of the same species. Were an observer to find only Nos. 1 and 4, he
would be almost justified in considering them distinct species; but when he discovers a
number of intermediate forms, by which the depressed, hemispherical, and conical varieties
are seen to blend into each other, he is convinced that they all belong to one and the same
species, and at the same time is taught the important lesson, that mere difference in
form and bulk alone do not constitute a specific character.

This fine urchin, the oldest of the genus, is the largest Hyboclypus we are acquainted
with ; it has a sub-orbicular or sub-pentagonal shape (Pl. XXI, fig. 1), and is the
most typical form of the discoidal variety No. a. It is expanded and depressed above,

294. HYBOCLYPUS.

with an acute and sinuous margin arising from the convexity of the inter-ambulacra
(fig. | c); the base is flat, or moderately concave, and is slightly undulated by the
depressions formed by the ambulacra, and the convexities by the inter-ambulacra. In
general the antero-posterior equals the transverse diameter, but sometimes the transverse
exceeds the antero-posterior diameter (fig. 1 a, 4).

The ambulacral areas are very narrow and of unequal width ; the anterior single area
is the narrowest; the antero-laterals are a little broader than the odd one, and narrower
than the postero-laterals (fig. 1 a); the three anterior areas converge around the front of
the apical disc, whilst the postero-laterals curve sinuously up to its posterior border
(fig. 1 a); each area has four or six rows of small tubercles, so arranged on the plates that
they form oblique rows, which meet in the median line, and branch upwards and
outwards, thereby forming v-shaped figures (fig. 1 d@). -

The poriferous zones are narrow; on the dorsal surface the pores are unigeminal,
and placed close together (fig. 1 7) ; at the base, in consequence of the plates being broader,
they are wider apart, and form slightly oblique ranks of threes; whilst nearer the mouth
they lie in very oblique trigeminal ranks (fig. 1 e); the oral portions of the ambulacra form
a radiate rosette around the mouth.

The inter-ambulacral areas are very wide, but of unequal width; on an average they
are elght times as broad as the ambulacrals (fig. 1 a, 4). In one specimen the anterior
pair measure at the circumference one inch and three tenths, the posterior pair one inch
and eleventh twentieths, and the single area is one tenth of an inch wider than the
posterior pair; the margin of all the areas is convex, except the posterior single inter-
ambulacrum, which is slightly truncated. The dorsal surfaces of the anterior and posterior
inter-ambulacral and of all the ambulacral areas are gently convex; but the single inter-
ambulacrum, which is somewhat wider and longer than the others, has a deep valley with
parallel vertical sides in its dorsal half; these gradually decline and expand into a concave
depression at the lower half (fig. 1 a, ¢).

The anal aperture opens into the upper part of this valley immediately below the
apical disc; the basal portion of the area is slightly produced and truncated, and forms a
lip-shaped process, which imparts a considerable prominence and convexity to it (fig. 1 ¢).

The base is concave and undulated (fig. 1 4, c), the ambulacra lie in nearly straight,
depressed valleys, whilst the inter-ambulacra form gentle convex eminences at the circum-
ference; the mouth opening is small and excentral, being nearer the anterior border;
when well exposed, the peristome is seen to be unequally decagonal, the ambulacral being
larger than the inter-ambulacral lobes (fig. 1 4).

The apical disc is small and central; the margin of the opening is notched with four
inter-ambulacral and five ambulacral notches, the former corresponding to the external
angle of the ovarial plates, the latter to the margins of the oculars (fig. 1 @); the disc
appears to have been lodged in a depression; but in none of the hundreds of specimens
which I have examined have I detected any of its elements.

FROM THE INFERIOR OOLITE. 295

The whole of the plates on the dorsal surface are covered with numerous, minute,
regular, and nearly equal-sized, perforated tubercles (fig. 1 fy), which are raised on bosses
with crenulated summits, and surrounded by depressed, ring-like areolas; on one plate
near the border I have counted as many as one hundred tubercles; the inter-tubercular
surface of the plates is, besides, strewed with microscopic granules, which form circles
around the areolas, and fill up the intervening spaces (fig. 1 f); the tubercles at the base
are much larger and better developed than those on the dorsal surface; at the border and
outer third they are very numerous and set close together; the areolas here are
diamond-shaped, or hexagonal, and are more excavated, a single row of granules only
separates the areolas from each other; towards the mouth they are larger, and not so
regularly arranged, having several rows of granules between them (fig. 1 e).

Affinities and differences—The adult forms of H. agariciformis, Forbes, differ so
widely from its other Oolitic congeners, that this urchin cannot be mistaken for either of
them ; its sub-orbicular shape and depressed dorsal surface distinguish it from ZZ. gid-
berulus, Agassiz, and ZH. ovalis, Wright; the central position of the apical disc, and the
absence of any elongation of the single inter-ambulacrum, are diagnostic distinctions
between it and H. caudatus, Wright. From the Pygasters, with which some of the
species have been erroneously grouped, it is distinguished by the microscopic character
and greater number of its tubercles; the deep anal valley, with vertical walls, in which
the vent opens, the small sub-central mouth opening, and narrow apical disc, form a
group of generic characters by which the Hydoclypi are distinctly separated from the
Pygasters ; whereas the narrow poriferous zones, complete and continuous from the mouth
to the apical disc, without any petaloidal expansion on the dorsal surface, distinguish
Hyboclypus from Clypeus, Echinobrissus, and Pygurus.

Locality and Stratigraphical position—This urchin is very abundant in the lower
ferruginous beds of the Inferior Oolite, ‘‘the Pea Grit’’ of Leckhampton, Crickley,
Cooper’s, Cleeve, and Sudely Hills, and at Camlong Down, near Uley Bury, in Glouces-
tershire. It was collected from the Inferior Oolite by the Geological Surveyors between
Wayford and Seaborough in Dorsetshire, where it was accompanied by Collyrites ringens,
Agassiz, and Holectypus hemisphericus, Desor. I have found two specimens in the Great
Oolite of Minchinhampton, Gloucestershire, along with Purpurina Morrisii, P. nodulata,
Young, and other species of Mollusca characteristic of that formation.

History.—Vhis species was first described in my Memoir on the CassipuLip# of the
Oolites, and afterwards figured by Professor Forbes in the IV Decade of the ‘ Memoirs of
the Geological Survey.’ In consequence of the opening for the apical disc having a
denticulated border, M, Cotteau has proposed for it the new genus Galeopygus ; but as I

296 HYBOCLYPUS.

have never seen any of the elements of the disc, I am unable to judge of the value of the
character on which the separation of this urchin into a new genus is proposed to be made.

Hyszociypus caupatus, Wright. Pl. XXII, fig. 2 a,b, ¢,d,¢,f, 9, h, 1,j, h

HyBociypus caupatus. Wright, Annals and Magazine of Natural History, 2d series,
_— — vol. ix, p. 100, pl. 3, fig. 2 a—e.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 82.
— — Desor, Synopsis des Echinides Fossiles, p- 193.

Test small, oblong, much depressed; the single inter-ambulacrum produced into a
caudal prolongation; mouth very near the anterior border; apical disc and vertex excen-
tral; anterior border rounded and elevated, the posterior produced, and truncated.

Dimensions.—Height, nine tenths of an inch; antero-posterior diameter, one inch and
two tenths; transverse diameter, one inch and one tenth. The great majority of the
specimens, however, have the following measurement: Height, seven twentieths of an
inch; antero-posterior diameter, fifteen twentieths of an inch; transverse diameter,
thirteen twentieths of an inch.

Description.—The test of this elegant little urchin has an oblong shape, rounded and
elevated before, produced and truncated posteriorly, and having the mouth and apical dise
excentral, placed much nearer the anterior than the posterior border; the surface of the
plates is covered with very small tubercles, which require the aid of a good lens to dis-
cover; without this the observer might suppose the test was altogether destitute of
sculpture (fig. 2 a, 6); in consequence of the excentricity of the mouth opening and disc,
the single and antero-lateral ambulacral areas are straight and short, and terminate at
the anterior border of the disc (fig. 22); the posterior pair are one seventh longer than
the anterior pair; they curve upwards, inwards, and forwards on the dorsal surface, and
terminate by the margin of the longitudinal valley, at a short distance from the posterior
border of the dise (fig. 2 a).

The poriferous zones are narrow; the pores are situated some distance apart on
the dorsal portion of the zones, and much wider apart at their basal region (fig. 2 6, /).

The inter-ambulacral areas are of unequal width; the anterior pair are the shortest
and narrowest, the posterior pair the widest, and the single area the longest; it is
likewise considerably produced into a lip-like process, which curves gently downwards,
and is abruptly truncated posteriorly (fig. 2 a, 6); the anterior and posterior pairs of the
inter-ambulacral, and all the ambulacral areas, are convex on the upper surface ; but the
single inter-ambulacrum is traversed superiorly by a deep, broad, longitudinal valley, with

FROM THE INFERIOR OOLITE. 297

vertical and parallel walls in the upper part, gradually expanding into two ridges at the
lower half, and which form the lateral boundaries of the anal valley (fig. 2 a).

The anterior border is bluntly rounded (fig. 2,7), with a slight depression in the middle,
formed by the single ambulacral area; the base is concave, and slightly undulated
(fig. 2 c), in consequence of the basal portions of the imter-ambulacral areas being convex,
and those of the ambulacral forming straight valleys between them (fig. 2 4). The
small mouth opening is sub-pentagonal, and (fig. 2 4) situated near the anterior third ;
the peristome is undulated, and the inter-ambulacral are smaller than the ambulacral
lobes ; the tubercles at the base are larger than those on the dorsal surface ; they are like-
wise fewer in number, and arranged with much irregularity on the plates (fig. 2 4).

The apical disc is fortunately preserved in one of my specimens (fig. 2 d); it is
formed of two small anterior ovarial plates, and two larger posterior ovarials; the right
anterior plate supports the spongy madreporiform body ; between the posterior ovarials
the single imperforate ovarial is situated, composed of two pieces, an anterior and a
posterior half (fig. 2 4). This arrangement of the genital plates is common to all the
Hyboclypi with preserved discs I have examined; I have therefore noted it as a character
common to the genus. The five ocular plates are small, and wedged between the
depressions formed by the ovarials; their eye-holes are marginal, whilst the perforations
in the ovarials are situated near the border.

The tubercles are small and numerous, each plate having three or four concentric rows
arranged in diagonal Jines on its surface (fig. 2g). As the dorsal portion of this pretty
little urchin varies considerably, I have given outlines in figs. c, f, 7, 4, of some of the
most remarkable deviations from what I consider as the typical form, fig. 2 ¢.

Affinities and differences.—Hyboclypus caudatus differs from the other Oolitic species
in its more oblong form, and especially in having the single inter-ambulacrum developed
into a kind of caudate process; by this character it is readily distinguished from H. gzé-
berulus, Agassiz, and H. ovalis, Wright, which it otherwise resembles; the mouth and
vent are likewise placed nearer the anterior border than in these allied forms. The sub-
orbicular shape which H. agariciformis invariably retains throughout its numerous varieties
of elevation and depression of the upper surface readily distinguish it from all the forms
of H. caudatus I have met with.

Locality and Stratigraphical position —This is rather a rare urchin. I have found it
occasionally in the upper beds of the Inferior Oolite, “the Grypheea Grit” of Leckhampton,
Birdlip, Shurdington, and Ravensgate Hills, associated with Gryphea sublobata, Desh.,
Lima pecteniformis, Scloth., Myopsis punctata, Buck., Cercomya rostralis, Wright, Tere-
bratula impressa, V. Buch. It occurs likewise in the Trigonia Grit at Hampen, associated
with Ammonites Parkinsoni, Sow., and the numerous other Mollusca and Echinida
which characterise that rich zone of life.

298 HYBOCLYPUS.

It is found occasionally in the planking beds of the Great Oolite at Minchinhampton
Common. The Great Oolite specimens, however, are small, and not well preserved. M.
Deslongchamps kindly communicated a specimen which he collected from the “ Oolite
ferrugineuse de Bayeux.” On the ticket which accompanied it was written, “ Seul
exemplaire que j’ai trouvé,” so that it is extremely rare in Normandy. This urchin very
much resembled our small common examples from the Inferior Oolite. I know it from no

other foreign locality.

HYBocLyPUs GIBBERULUS, Agassiz. Pl. XXI, fig. 2 a, 4, ¢, d, e, fg.

HYBOCLYPUS GIBBERULUS. Agassiz, Echinodermes Fossiles de la Suisse, part i, p. 75, pl. 13,
figs. 10—12.
— — Desor, Monographie des Galérites, p. 84, pl. 13, figs. 12—14.
= — D’Orbigny, Prodrome de Paléontologie, tom. i, p. 290,
étage 10°, Bajocien.
— — Bronn, Lethaea Geognostica, 3° Aufl., tabl. 17’, fig. 11.
— — Agassiz and Desor, Catalogue raisonné, Annales des Sciences
Naturelles, tom. vii, p. 152, série 3°.
— — Desor, Synopsis des Echinides Fossiles, tabl. 26, figs.11—13,
p- 192.
NUCLEOLITES EXCISUS. Quenstedt, Handbuch der Petrefactenkunde, tabl. 1, fig. 3,
p- 585.

Test oblong, elevated above, and contracted on the sides before ; enlarged, depressed,
produced, and truncated behind; single ambulacral area the highest, and, with the
antero-lateral imter-ambulacral areas, form a gibbous crest; longitudinal valley wide
and deep ; single inter-ambulacrum slightly produced, deflected, and truncated ; base much
undulated, a depression in the anterior border; apical disc elongate, nearly central, but
not vertical; vent very wide, opening at the inner extremity of the valley ; mouth opening
small, oblong, sub-central, near the anterior border.

Dimensions.—Height, nearly one inch;..transverse diameter, two inches and one tenth
of an inch; antero-posterior diameter, two inches and one tenth of an inch.

Description.—This urchin has so singular a form, that when once seen, it is not
likely to be mistaken for any other, being remarkable for a prominent gibbous crest
(fig. 2 d, e), which rises from the anterior half of the test, formed by the elevation of the
single ambulacral area, and the two anterior inter-ambulacral areas; from the anterior
border to the mouth a depression extends (fig. 2 4, d); the anterior lateral are more
contracted than the posterior lateral borders (fig. 2 a, 4); the posterior half of the test

FROM THE INFERIOR OOLITE. 299

is less elevated than the anterior half (fig. 2 e), and gradually declines from the vertex to
the posterior border, which is a little produced and truncated (fig. 2 a, 4).

The ambulacral areas are of unequal width; the single area is the narrowest, the
anterior pair are a little wider, and the posterior pair are the widest; the single area
makes a straight line from the mouth to the vertex; its upper half forms the ridge
of the anterior gibbous crest (fig. 2 ¢); where it turns round the border a depression
is formed, both there and at the base (fig. 2 4, d), by the bulging out of the inter-
ambulacra ; the anterior pair, between the border and the disc, are gently curved back-
wards (fig. 2 e), and the posterior pair are sinuous (fig. 2 a); the single and anterior pair
terminate around the front of the disc (fig. 2 a), which is elongated in the longitudinal
direction ; the posterior pair terminate in the large specimen (fig. 2 a) within the longi-
tudinal valley, one quarter of an inch behind the anterior pair; in each area there are six
rows of tubercles, arranged so that they form oblique v-shaped lines (fig. 2/7).

The poriferous zones are narrow, and, from the border to the disc, the pores are
placed close together, whilst, from the border to the mouth, they are wide apart (fig. 2 a) ;
this arises from the ambulacral plates on the dorsal surface being narrow, whilst those at
the base are broad ; there are six pairs of pores opposite each of the large fourteen plates on
the upper surface, which makes eighty-four pairs of pores on the dorsal portion of the
zones, whilst there are only about fifteen pairs of pores in the base.

The inter-ambulacral areas are of unequal width; the anterior pair are the narrowest ;
the posterior pair are one third wider than the anterior, and the single inter-ambulacrum
is the widest (fig. 2 a); the middle of its dorsal portion is occupied by the longitudinal
valley, which is wide and deep above, and shallow and expanded below; the small and
numerous tubercles are arranged very closely and regularly together in four or five
concentric rows (fig. 2 7); and I have counted upwards of one hundred tubercles on
one large plate near the margin.

The tubercles are very numerous at the border and external third of the base, whilst
they are fewer, larger, and less regular between that point and the mouth; they are
all perforated, and raised on low, crenulated bosses, surrounded by sunken circular
areolas (fig. 2 7); the inter-tubercular surface of the plates is likewise covered with
close-set miliary granules (fig. 2 g).

The base is concave, and much undulated (fig. 2 4, c), the basal portions of the inter-
ambulacra being very convex (fig. 2 d), whilst the ambulacra lie in narrow valleys between
them ; the small mouth opening is sub-central, and situated nearer the anterior border,
almost opposite to the vertex (fig. 2 4) ; the peristome has a sub-pentagonal form, but its
minute structure is more or less concealed in all my specimens.

The apical disc is nearly central; it lies behind the summit of the crest, which rises
above it (fig. 2 e), so that the vertex is before the disc in this remarkable species ; it has

a narrow, elongated form, and is composed of six ovarial and five ocular plates (fig. 2 ¢
39

300 HYBOCLYPUS.

gives a faithful representation of the disc); the anterior are smaller than the posterior
ovarials ; the right is larger than the left plate, and supports, as usual, a spongy madre-
poriform body; the posterior ovarials are large and elongated, and separated from the
anterior pair by the excessive development of the anterior pair of ocular plates, which form
an important part of the disc; the large oviductal holes always indicate the true relative
position of the genital plates; the single imperforate ovarial is composed of two plates,
placed end to end, and behind the posterior ovarials the posterior pair of ocular plates
are placed. M. Desor’s figure of the disc of this species does not agree with our speci-
mens, as the single imperforate ovarial, which is central and double, is entirely wanting
in his figure, probably through an oversight on the part of the artist. I have verified
Mr. Bone’s beautiful drawing in three different individuals by a careful examination with
the lens.

Affinities and differences.—This remarkable urchin, which formed the type of the
genus, is so well characterised by its gibbous crest that it cannot be mistaken for any
other species. 7. ovalis has a considerable resemblance to it; but the absence of the crest,
its oval form, and the want of those prominent traits which distinguish H. gibberulus,
clearly distinguish them from each other.

Locality and Stratigraphical position.—I have collected this species in the upper beds
of the Inferior Oolite, in the zone of Ammonites Parkinson, Sow., at Burton Bradstock,
and Walditch Hill, near Bridport, Dorset ; a few specimens have been found in the Inferior
Oolite in the parish of Charleomb, near Bath. The Dorsetshire specimens were associated
with Holectypus hemisphericus, Desor, Stomechinus bigranularis, Lamk., Clypeus altus,
M ‘Coy, Collyrites ringens, Agass., Terebratula spheroidalis, Sow., Rhynchonella plicatella,
Sow., Zerebratula Phillipsii, Mor., Ammonites Parkinson, Sow., Ammonites sub-radiatus,
Sow.

It appears to be a rare species on the Continent. M. Desor observes, ‘ Suivant les
indications que m’a fournies M. Gressly, on la trouve dans une couche particuliére de
lOolite inférieure, la marne 4 Ostrea acuminata, la méme qui contient aussi Discordea
(Holectypus) depressa, et le Dysaster analis, c’est au moins dans cette couche que Va
rencontrée M. Strohmeyer.”* In his ‘Synopsis des Echinides Fossiles,’ M. Desor gives,
as the other foreign localities of this species, ‘‘ Vesulien (Marnes a Discoidées du Jura
Soleurois et Argovien, du Hummel, prés Waldenburg. Grande Oolite de Macon (Hébert),
du départ. de / Ain.”

M. De Loriére has sent mea specimen which he collected at “ Nogent, étage Callovien,
département de la Sarthe ;’ and from M. Semann I have received another from the
étage Callovien of the same department. I have already expressed a doubt as to the age

?

* Monographie des Galérites,’ p. 85.

FROM THE INFERIOR OOLITE. | 301

of the beds which have yielded Hyboclypus gibberulus, Pygurus depressus, and Collyrites
ringens, in the department of the Sarthe; my friend M. Cotteau is at this moment
engaged on a work on the Echinoderms of that department, and my friend M. Triger
has undertaken a review of the stratigraphical distribution of the species. From this
monograph we shall therefore learn the true age and position of these strata.

History.—This species was first figured and described by M. Agassiz, in his
‘ Hchinodermes Fossiles de la Suisse,’ he only knew two specimens from the Inferior Oolite
of Switzerland. It was afterwards figured by M. Desor in his valuable ‘ Monograph
on the Galerites,’ and was described by me as a British fossil for the first time.* It has
lately been figured by M. Bronn in his ‘ Lethaea Geognostica,’ and by M. Desor in
his ‘Synopsis des Echinides Fossiles.’

Hysoctypus ovauis, Wright, nov. sp. Pl. XXII, fig. 1 a, 4, ¢, d, e, f.

Test oval or suborbicular, upper surface convex, rather more elevated anteriorly ;
ambulacral areas narrow, nearly of equal width; the single and anterior pair straight ;
posterior pair curved gently upwards, inwards, and forwards; apical disc small, nearly
central, rather nearer the anterior border; longitudinal valley of moderate width and
depth; base concave and undulated, from the convexity of the basal inter-ambulacra ;
mouth opening small, excentral, nearer the anterior than the posterior border.

Dimensions.—Height, seven tenths of an inch; transverse diameter, one inch and
eleven twentieths ; antero-posterior diameter, one inch and thirteen twentieths.

Description.—This species very much resembles 1. yibderulus, but it wants the striking
features of that urchin; the contracted anterior border, expanded posterior border, wide
anal valley, and prominent gibbous crest are absent ; although in the minute structure of
the test there is much resemblance between them. It is collected, moreover, from the same
stratigraphical horizon, the zone of Ammonites Parkinsoni, Sow., and may be regarded as
the representative of HZ. gibberulus in the Cotteswold Hills, as that species, so far as
I know, has never yet been found in this district.

The test is in general oval, but it has sometimes a sub-orbicular shape (fig. 1 a).
The upper surface is very uniformly convex, and the anterior part is rather more elevated
than the sides (fig. le); most Hyéoclypi manifest a disposition to the formation of

* © Annals and Magazine of Natural History,’ 2d series, vol. ix, p. 120.

302 HYBOCLYPUS.

an anteal elevation of the test, which attains its greatest development in 1. gebderulus.
(See fig. 2. f, £.)

The ambulacral areas have all nearly a uniform width; the single and anterior pair
are nearly straight, and converge around the front part of the disc (fig. 1 a); the posterior
pair are a little bent, and curve upwards, inwards, and forwards, to terminate at
the posterior lateral part of the disc, their apices just fallmg within the longitudinal valley.

The apical disc is large, and formed of seven ovarial and five ocular plates; the
two pairs of ovarials are perforated ; the single plate is imperforate, and composed of three
pieces (fig. 1 e); the pairs of ovarials expand between the apices of the ambulacra, and the
posterior elements of the single plate bend over the upper part of the longitudinal valley
(fig. 1 a); the madreporiform body is round, button-shaped, and placed between the
anterior and the right antero-lateral ambulacra ; it therefore rests on the surface of the
right ovarial plate, as in other Ecuintpa@. ‘The single ocular plate is small; the anterior
pair are large, and placed side by side in the centre of the disc, between the anterior and
posterior pairs of ovarials; but the posterior oculars are not seen a” situ in any of my
specimens.

The base is concave, and much undulated, from the convexity of the basal portions of
the inter-ambulacral areas ; the mouth opening is small and excentral, it has an oval form,
its long diameter being in the direction of the antero-posterior diameter of the body ;
around the border of the opening the poriferous zones become closely crowded with pores,
which le in triple oblique pairs, and form a radiate rosette around the orifice.
These areas are well seen in fig. ] 6, and a portion of one of them, magnified, is drawn in
fig. 1 f, where each of the broad plates are seen to be perforated with a pair of pores,
having one, two, or three large tubercles on their surface.

There are four or five rows of small tubercles, so arranged on the plates that they
form, as in most of the Ecurnoconipa, oblique V-shaped lines (fig. 1 d). The poriferous
zones are narrow, and on a level with the general surface of the test; the pores are placed
close together on the dorsal surface, there being six pairs of pores opposite one inter-
ambulacral plate; at the base they are wide apart, from the imcreased breadth of the
ambulacral plates in this region (fig. ] 6 and /).

The inter-ambulacral areas are five or six times the width of the ambulacral
(fig. 1 a@ and 4); they are, however, of unequal width; the anterior pair are the narrowest,
the posterior are wider, and the single area is the widest; in its upper part is the
longitudinal valley, which is very deep above, with vertical walls, that expand in the lower
half, and form a concave depression (fig. 1 a); the posterior border, which is very little
produced, is rounded, or only slightly flattened (fig. 1 @ and 4), and not truncated, as in
H. caudatus and H. gibberulus. he tubercles are small, and very numerous (fig. | @) ;
they are arranged in concentric rows, and I have counted fifty tubercles on the
third plate, above the border; they are surrounded by sunken areolas, and the inter-

a

[Bu it an /. 7 or
FROM 'THE CORAL RAG. 303

tubercular surface is crowded with small granules; the tubercles in both areas are
of the same size.

Affinities and differences.—This urchin in its general facies bears so much resemblance
to H. gibberulus, Agass., that at one time I considered it a variety of that species; but the
absence of the gibbous crest, the fulness of the anterior border, the straightness of
the anterior ambulacra, the form and direction of the posterior pair, together with the
difference observed in the shape of the longitudinal valley, have induced me to separate it
from that species under the name //. ovalis. By its oval shape and elongated apical disc
it is distinguished from HH. agariciformis, and by the shortness of the single inter-
ambulacrum from A. caudatus.

Locality and Stratigraphical position have collected this species only from the
marly fossiliferous vein which traverses the upper ragstones of the Inferior Oolite, in the
zone of Ammonites Parkinsoni, Sow., near Hampen, Gloucestershire, where it is associated
with Holectypus depressus, Leske, H. hemisphericus, Desor, Pedina rotata, Wright, Clypeus
Hugi, Agass., Clypeus Plottii, Klein, Trigonia costata, Sow., Pectin symmetricus, Morris,
Ammonites Parkinsoni, Sow. Ihave found one specimen in the Trigonia bed at Cold
Comfort, where it was associated with the large Perna isognomonoides, Stahl.

B. Species from the Coral Rag.

Hysocuyeus srELLatus, Desor.

HyBocLypus sTELLatus. Desor, Catalogue raisonné Annales des Sciences Naturelles,
3° série, tome vii, p. 152.
_— — Desor, Synopsis des Echinides Fossiles, p- 193.
— mMARcoU. D’Orbigny, Prodrome de Paléontologie, tome ii, p. 26.

This urchin is described by M. Desor as “ Espéece intermédiaire par sa forme, entre les
HT. canaliculatus et H. Marcou, mais différant de lun et de l’autre par ses ambulacres
posterieurs qui sont rectilignes au lieu d’étre arqués. T. 76 (type du l’espece).

‘** Formation.—Corallien du Wiltshire. Rare.

“© Collection.—M. le Viscomte d’Archiac.”’

I only know this species from the above notice, as I have never been so fortunate as
to see a specimen of it in any of the collections of Coral-rag urchins which I have
examined.

40

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PALMONTOGRAPHICAL SOCIETY.

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A MONOGRAPH

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BRITISH FOSSIL

ECHINODERMATA

FROM

THE OOLITIC FORMATIONS.

BY

THOMAS WRIGHT, M.D., F.RS.E. F.G.S.

CORRESPONDING MEMBER OF THE ROYAL SOCIETY OF SCIENCES OF LIEGE,
AND SURGEON TO THE CHELTENHAM HOSPITAL.

PART THIRD,
THE COLLYRITIDA, ECHINOBRISSIDA, AND
ECHINOLAMPID A.

LONDON :
PRINTED FOR THE PALAONTOGRAPHICAL SOCIETY.
1859.

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FROM THE INFERIOR OOLITE. 303

tubercular surface is crowded with small granules; the tubercles of both areas are the
same size.

Affinities and differences.—This urchin in its general facies bears so much resemblance
to H. gibberulus, Agass., that at one time I considered it a variety of that species ; but the
absence of the gibbous crest, the fulness of the anterior border, the straightness of
the anterior ambulacra, the form and direction of the posterior pair, together with the
difference observed in the shape of the longitudinal valley, have induced me to separate it
from that species under the name 7. ovalis. By its oval shape and elongated apical disc
it is distinguished from “4. agariciformis, and. by the shortness of the single inter-
ambulacrum from . caudatus.

Locality and Stratigraphical position—I have collected this species only from the
marly fossiliferous vein which traverses the upper ragstones of the Inferior Oolite, in the
zone of Ammonites Parkinsoni, Sow., near Hampen, Gloucestershire, where it is associated
with Holectypus depressus, Leske, H. hemisphericus, Desor, Pedina rotata, Wright, Clypeus
Hugi, Agass., Clypeus Plottii, Klem, Zrigonia costata, Sow., Pectin symmetricus, Morris,
Ammonites Parkinson, Sow. I have found one specimen in the Trigonia bed at Cold
Comfort, where it was associated with the large Perna tsognomonoides, Stahl.

B. Species from the Coral Rag.
HyYBocLyPus STELLATUS, Desor.

HyYBOCLYPUS STELLATUS. Desor, Catalogue raisonné Annales des Sciences Naturelles,
3° série, tome vil, p. 152.
— — Desor, Synopsis des Echinides Fossiles, p. 193.

This urchin is described by M. Desor as “ Espéce intermédiaire par sa forme, entre les
HH. canaliculatus et H. marcon, mais différant de Yun et de l’autre par ses ambulacres
postérieurs qui sont rectilignés an lieu d’étre arqués. 'T. 76 (type du l’espéce).

«© Formation.—Corallien du Wiltshire. Rare.
** Oollection—M. Le Viscomte d’Archiac.”’

I only know this species from the above notice, as I have never been so fortunate as
to see a specimen of it in any of the collections of Coral-rag urchins which I have
examined.

dj 40

304

Family 7—COLLYRITIDAL, Wright, 1856.

Famille 7me—Dysast&RIDiEs, Albin Gras, 1848.
Famille \re—Couuyrit1pm, D’ Orbigny, 1853 (pars).
Famille des Dysastiripirs, Desor, 1856.

The urchins forming this family have a thin test which, in general, has an ovoid,
elongated, or cordiform shape. The ambulacral areas converge at two points on the
upper surface, which are more or less apart, whilst in all other Echinoidea, they
converge towards one point, the apical disc, around which are the genital apertures,
and the holes for the eyes. In the Cotiyritipm, on the contrary, the ambulacra
are divisible into two groups, the anterior, composed of the single area, and the anterior
pair, meet at the apical disc, which is composed of the three anterior ocular, and four
genital plates; the posterior, composed of the posterior pair of ambulacra, meet
at some distance from the former, and form an arch over the anal opening. ‘This
disjunction of the ambulacra occasions a corresponding separation of the elements
of the apical disc, as three of the ocular plates are placed before, and two behind, at
the apices of the ambulacral areas; the four genital and three anterior ocular plates are
intimately soldered together at the union of the three anterior ambulacral areas, and which
junction forms the true vertex of the test.

The poriferous zones are narrow, the pores are unigeminal, and the tubercles in
general small, numerous, perforated, and crenulated.

The mouth-opening is small, and placed near the anterior border; the peristome
is oval or circular, and its margin is entire; the anal opening is round or oval, and is
situated in the region of the posterior border, over which the two posterior ambulacra form
an arch, the summit of which is more or less distant from the vent.

This family forms a small, natural group of urchins, connected with the Ecurnocoripaz
on the one side, and with the Hournoconip# and Sparaneip# on the other. Like the
Ecuinoconip#, the ambulacral areas in the CoLLyrivip# are narrow, the poriferous zones
complete, the pores unigeminal throughout, and the tubercles perforated and crenulated.
The genus Hyboclypus connects these two families by the elongated arrangement of the
elements of the apical disc, and the partial disjunction of the apices of the three
anterior from the two posterior ambulacra m that small group.

In the ovoidal form of the test, the structure of the ambulacra, and poriferous zones,
the excentrical position of the mouth, and the supra-marginal situation of the vent,
the Cotiyritipm resemble the genus /olaster, by which they are connected with
the family Ecurnocorip#, but their two distinct ambulacral summits, placed at some
distance apart, and the consequent disjunction of the posterior ambulacra from the apical

COLLYRITID A. 305

dise, form a diagnostic character between them, and afford a good zootomical reason why
they should not be united in one family, as proposed by the late M. A. d’Orbigny.

The petaloidal character of the ambulacra, circumscribed for the most part by /asczoles,
the bilabiate structure of the mouth, the completeness of the apical disc, and the union of
the ambulacra around the same, form a group of characters by which the Sparancips&
are distinguished from the Conirririp#, which they only feebly resemble in external
form, being widely separated from that family by organic structure.

M. Desor, who has carefully studied the species of this family, and figured them
in his excellent ‘ Monograph on the Disasters,’* has made the following remarks on
the affinities of the Co~nyrivipa, in his latest work now passing through the press.
“On nous objectera peut-ctre qu’il existe certains types, leg Ananchydées par example,
chez lesquels les ambulacres ne sont qu’imparfaitement bornés, et qui n’en sont pas
moins trés voisins des Spatangoides. Nous répondrons a ceci que cette ressemblance des
Ananchydées avec les Dysastéridées est plus apparent que réelle. Sans doute que vus par
en haut, les ambulacres des Ananchydées n’ont pas cette apparence pétaloide qui
charactérise & un si haut dégré les Clypéastroides, les Cassidulides et les vrais Spatangoides.
Mais qu’on les regarde par la face inférieure et l’on retrouvera le véritable type des Spatan-
goides, savoir de tres larges plaques ambulacraires en général lisses et percees d’une seule
paire de pores, tandis que chez les Dysaster les plaques ambulacraires de la face supérieure
ne subissent aucun changement sensible, et sont beaucoup plus petites que les plaques
inter-ambulacraires. Il y a donc sous ce rapport une bien plus grande varicté de
structure ambulacraire chez les Ananchydées. De plus ces derniers ont en général
le péristome bilabié et, ce qui est plus significatif, ’ambulacraire impair est different
des ambulacraires pairs, tandis que chez les Dysastéridées tous les ambulacres sont égaux.
Ces considérations suffiront, je Pespére, pour expliquer pourquoi nous n’avons pas suivi
Yexample de M. d’Orbigny qui réunit les Dysaster et les Ananchydées en une seule
famille, sous le nom de Collyridées. :

“D’une autre cote, il importe également qu’on ne confonde pas les Dysasteridées avec
les Galéridées, comme on a pu étre tenté de le faire 4 une certaine époque, alors que la
structure intime du test n’était pas suffisamment étudiée. Le fait que chez certains
Galénidées particuliérement ceux du second type, les ambulacres ne convergent pas
complétement ne constitue pas encore un démembrement de l’appareil apicial. L’écarte-
ment plus ou moins considérable des ambulacres n’est ici que la conséquence d’une
disposition particulicre des plaques ocellaires qui, au lieu d’étre rejettées dans les angles
externes des plaques genitales, se placent avec elles sur le méme rang. Mais
Yunité de Vappareil apicial n’est pas rompu pour cela. C’est une combinaison
qui se produit également dans la famille des Ananchydées, dans celle des Galéridées et
meme chez certains Dysastéridées.”

* Monographie des Dysaster, 1842.
+ ‘Synopsis des Echinides Fossiles,’ p. 200.

306 COLLYRITID A.

The family Cottyritip# includes ot present four genera Disaster, Collyrites, Metapo-
rhinus, and Grasia, which are limited to the Oolitic and Cretaceous rocks. The most
ancient form at present known was found in the lias; the species attamed their
greatest development in the middle division of the Oolites, are sparingly found in the
Neocomian, and Lower Cretaceous rocks, and finally disappear with the White Chalk.

The following table exhibits the stratigraphical distribution of the Oolitic species
of this family.

STRATIGRAPHICAL DISTRIBUTION OF THE OoLrtic SPECIES OF THE COLLYRITIDA.

o
3 | 3 3
fs) PS S| a |e
[2 on}
List of Species. 5 2 = = iE 2 Type localities.
a] | Oo 2] ©) iS) MS
DISASTER.
Disaster granulosus, Desml. i PAlmberomSielunene.s Wiurtemberg.
33 anasterotdes, Leym. see ie (sora sm ae * | Bar-sur-Aube (Aube).
», Moeschii, Desor —}|—|—| * |—]|—|—| Kornberg (Argovie).
CoLLYRITEs.
Collyrites prior, Desor * | —}| —| —}| —| — — | Frick, (Canton d’Argovie).
ie ringens, Desml. . —| * | * |—|—|—|—| England, France, Switzerland.
45 ovalis, Leske —j|* | * | —|—}|—|—| England, France, Switzerland.
» elliptica, Desml. . —{—|—]| * | —|—|—| Chaufour, Mamers (Sarthe).
5 castanea, Desor . —|—|—| * | —|—|— |St. Croix, de Pouillerel.
» transversa, D’Orbig. —{|—/—| * |—|—|—| Escragnolles (Var).
Bs bicordata, Leske . — |—|—|—| * | * |—| England, France, Switzerland.
» carinata, Desml. . —|—|—|—| * colar Gunsberg (Canton Soleure.)
An capistrata, Desml. .|—}|—}|—]|—|— * |— | Wiirtemberg, Switzerland.
65 Buchti, Desor . .|—|—|—|—|— * |— | Sirchingen, Wiirtemberg.
Bs Voltizi, Agass. . —|{—}]—|—| * |—|—| Voirons prés Genéve.
- IDxoome, CONE |) ==) |) || = | * | — | Chatel-Censoir, Druges (Yonne).
>» pinguis, Desor | ot zberam Gcissberea(ameovle)e
» Orbigniana, Cotteau | | = | a Slane (Crome),
», Lory, Alb. Gras. SS | ee ep ichiallong (sere):
»» acuta, Desor —|—|—||— | * | —|— | Villiers-les-Hauts (Yonne).
» conica, Cotteau . — |—|—|— | * | —|—| Pacey, Ancy-le-Frane (Yonne).
» faba, Desor —|—|—| * |—|—]|—| Ueken prés d’Effingen (Argovie).
METAPORHINUS.
Metaporhinus Michelinii, Cott. .|—}—|—|—|—| * | —| Chatel-Censoir (Yonne).
os Censoriensis, Cott.| —|—|—|—|—] * | — | Chatel-Censoir (Yonne).
GRASTA.
Grasia elongata, Alb. Gras. —|—|—|]—!—| * |—| Echaillon (Isére).

307

Genus—COLLYRITES,* Deluc, 1831; Desmoulins, 1835.

Disaster, Agassiz, 1836.
Disaster, Desor, 1842.
Cottyrites, d Orbigny, 1853.
CoutyriteEs, Desor (pars), 1857.

The generic characters of this group have been already indicated in our description
of the family of which it is the type. ‘The Collyrites, in general, are urchins of moderate
size, although some species attain a considerable magnitude. They have an ovoid, oblong,
cordiform, or triangular shape, more or less depressed on the dorsal surface, and have the
anterior border slightly grooved, with an anteal sulcus, in which the single area is lodged.
The ambulacral areas are disjoined, and form two distinct summits on the dorsal surface ;
the anterior, composed of the single area and anterior pair, occupies the anterior third of
the dorsal surface ; and the posterior, composed of the posterior pair, meet over the vent
near the posterior third. The poriferous zones are narrow, equal, and complete; the pores
unigeminal, the holes round, oval, or oblong; and the zones visible throughout from
the mouth to the summits.

The apical disc, situated at the anterior summit, at the junction of the three anterior
ambulacra, is composed of four perforated genital plates, between which are interposed
two large, ocular plates. The right antero-lateral genital plate is the largest, and supports
a prominent, spongy, madreporiform body ; the anterior ocular is a very small plate, which
is lodged between the anterior genitals. The two posterior ocular plates are seen only in
well-preserved specimens at the apices of the posterior ambulacra.

The mouth-opening is situated in the anterior third of the base; the peristome
is obtusely pentagonal, approaching a circular form.

The oval or elliptical anal opening is situated in the middle of the posterior
border, and is in general destitute of a distinct anal area, and always without a fasciole.

The tubercles are small, uniform in size, and are perforated and crenulated ; the miliary
granules are small and numerous.

The first known species of this genus were placed by systematic authors in different
genera, with which they had few characters in common. Leske grouped them with the
Spatangites, Lamarck with the Ananchytes, Defrance, Goldfuss, and Minster, with the
Nucleolites. In 1831, M. Deluc, in a letter to M. Desmoulins,} proposed for the urchin
which Lamarck named Ananchytes elliptica, that of Collyrites sub-elhiptica, but it was not
until August, 1835, that M. Desmoulins established definitely the genus Collyrites.t

* From the Greek Collyra, a little loaf.
+ Desmoulins ‘ Etudes sur les Echinides,’ ler Mémoire, p- 47.
t Desmoulins, loc. cit., p. 46.

308 COLLYRITES

About the same time M. Agassiz, was actively engaged in collecting materials for his
great work on the Echinodermata, and in the course of 1836 appeared his Prodrome,* in
which an important reform was proposed in the arrangement of that class, and
many new genera were therein described for the first time ; among these, was the genus
Disaster, which nearly corresponded to the genus Collyrites of Desmoulins. The pub-
lication of this work formed an era in the History of the Hchinide, and the author’s
classification and nomenclature was soon adopted by the naturalists of England, France,
and Germany. In a note appended to the first page of the Prodrome, it was stated, that
the memoir had been read before the Society of Natural Sciences at Neufchatel, on the
10th of January, 1834,+ which gave the Prodrome an apparent priority to the Mémoires of
M. Desmoulins, and thus the genus Disaster, Agass. was adopted to the exclusion of the
ganus Collyrites, Desml. A closer investigation into the question of priority, however,
showed that the memoir of M. Desmoulins was published in August, 1835. ‘The Prodrome
of M. Agassiz had been read in 1834, but was not published until July, 1836. In the
interval which had elapsed between the reading and publication of the memoir, M.
Agassiz had introduced into his work many important modifications, so much so, that the
work published in 1836, was no longer the work which had been read in 1834 ; according,
therefore, to the laws of nomenclature, the date of publication, and not that of the reading
of a paper, after subsequent alterations and modifications, must serve to decide disputed
points of priority in all quéstions affecting the natural history sciences.

In contending for the priority of his genus, M. Desmoulins{ says—

‘Le Prodrome de M. Agassiz a été publié en 1836, dans le 1* tome des ‘ Mémoires
de la Société d’ Histoire Naturelle de Neuchatel’ j'ai done un an d’antériorité sur lui. I
est vrai que ce Prodrome, d’aprés une note placée a la premitre page, a été lu le 10
Janvier, 1834, a la ‘Societic d’Hist. Nat. de Neufchatel, ce qui semblerait, dans un
certain sens, faire tourner l’antériorité au profit de M. Agassiz; mais comme, dans ce
travail, M. Agassiz adopté aux genres éfablis par M. Gray en 1835 (publiés d’apres les
renseignemens que j’ai pu recueillir en Octodre, 1835), il s’ensuit: 1° Que le travail de
M. Agassiz n’a pas pu étre, en 1836, dmprimé tel qu’il avait été lu en 1834, et que
des details de genres et d’espéces ayant été modifiés entre la lecture et limpression,
celle-ci seule prend une date authentique pour les noms de genres. 2° que jai une
antériorité d’un an sur le genre Disaster de M. Agassiz, et une antériorité de deux mois
sur l dAréacia de M. Gray. Done j’ai pu et dt conserver ma propre nomenclature, comme
la plus ancienne. J’avais soumis cette question, avec tous ses détails, a un juge éclairé,
parfaitement expert en ces sortes de matiéres, et j'ai agi d’apres la decision motivée.

These historical facts are sufficient to justify the restoration of genus Co//yrites, Desml.

** «Prodrome d’une Monographie des Radiaires ou Echinodermes,’ dans le premier tome des ‘ Mémoires
de la Societé des Sciences Naturelles de Neufchatel,’ 1836.

+ ‘Memoires de la Soc. d’Hist. Nat. de Neufchatel,’ tome i, p. 168.
{ ‘Etudes sur les Hchinides,’ premi¢re Mémoire, p. 207.

FROM THE INFERIOR OOLITE. 309

in preference to that of Disaster Agass., by which name the urchins included in this group
have been long known to English Geologists through the classical monograph on this
genus published by M. Desor, in 1842.

A. Species from the Inferior Oolite.

CoOLLYRITES RINGENS, Agassiz. Pl. XXII, fig. 3 a, 4,¢,d,¢,f, 9, h, 7.

DYSASTER RINGENS. Agassiz, Prodromus, 1° vol., des Mém. de la Societé des Sciences
Naturelles de Neufchatel, 1836.

COLLYRITES RINGENS. Desmoulins, 3° Mémoires sur les Echinides, p. 368, 1837.

DYSASTER RINGENS. Agassiz, Echinoderm. Foss. de la Suisse, 1" partie, p. 5, tab. 1,

figs. 7—11, 1839.
— — Agassiz, Catalogus Systematicus, Ectyp. foss. p. 3, 1840.
= — Desor, Monographie des Dysaster, p. 24, tab. 1, figs. 13—17,

1842.
— — Agassiz and Desor, Catalogue raisonné des Echinides, Annales des
Sciences Naturelles, 3° série, tome viii, p. 33, 1848.
— Eupssir. Agassiz, Catal. System, Ectyp. foss. p. 3, 1840.
— — Desor, Monographie des Dysaster, p. 23, tab. 1, figs. 5—12, 1844.
— suUBRINGENS. M‘Coy, Annals Nat. Hist., 2d series, vol. , p. 415, 1848.
— RINGENS. Forbes, Mem. of the Geol. Survey, decade 3, pl. 9, figs. 1—10,
1850.
— _ D’Orbigny, Prodrome de Paléontologie, tome i, p. 289, 1850.
— — Wright, Annals of Nat. Hist., 2d series, vol. ix, p. 207, 1851.
== — Cotteau, Etudes sur les Echinides Fossiles, p. 46, pl. ii, figs.
10—13, 1852.
—- Forbes, in Morris’s Catalogue of British Fossils, 2 ed., p. 78, 1854.
CoutyritEs RINGENS. Desor, Synopsis des chinides Fossiles, p. 207, 1857.
— — Cotteau and Triger, Echinides du Département de la Sarthe,
pl. viii, figs. 5, 6, p. 48.
— Evupisit. D’Orbigny, Paléontologie Francaise Ter. Cretacés, t. vi, p. 49,

1853.
— — D’Orbigny, Note rect. sur divers genres d’Hchid., Rev. Mag. de

Zool., 2° série, t. vii, p. 26, 1854.

Test sub-orbicular or sub-pentagonal, rounded anteriorly, rostrated posteriorly ; upper
surface convex, more or less depressed; sides tumid; vertex nearly central; apices of the
ambulacra widely disjomed, posterior pair forming an arch over the anal opening; vent
pyriform, situated in a sulcus on the posterior margin ; base concave, very much undulated,
inter-ambulacra extremely tumid, single posterior area very prominent and much deflected ;
mouth-opening small, sub-central, and sub-pentagonal.

Dimensions.—Height seven tenths of an inch ; antero-posterior diameter one inch and

one tenth ; transverse diameter one inch and one twentieth.

310 COLLYRITES

As this urchin presents very variable proportions, I subjoin a table, by Professor
Forbes, showing the dimensions of eight specimens from the inferior Oolite of Dorsetshire,
measured in inches and twelfths.

A B Cc D E F | G 13
r a
| Ileneth 1b 14, 044 0-85 012 0335 Ox! c=
1p,
| Breadth . 1 I 04 0-85 0-8, 0-5 049 042
Thickness 6 8 Z i L i 6
Thickness . 0-25 0-8 OG 0-5 055 | 0,3, Oe, 0-5

Description.—The preceding table shows how much the general outline of this curious
urchin varies in different individuals, so much so, indeed, that out of the varieties of
Collyrites ringens, no less than three other species, C. Hudesii, Agass., C. Agassizii,
d’Orb., C. subringens, M‘Coy, have been described and proposed as distinct species.
Having carefully examined and compared upwards of one hundred specimens of this
urchin, I can confidently state that the orbicular, sub-pentagonal, and oblong varieties met
with in the Inferior Oolites of Dorsetshire, are all referable to one and the same species,
the extreme forms in different individuals being blended together by numerous intermediate
gradations of structure.

The dorsal surface is uniformly smooth and convex, and more or less depressed,
it is elevated posteriorly, and declines gently anteriorly, the vertex in general is situated
nearer the anterior than the posterior border (fig. 3 c); the sides are tumid, the
anterior border is flattened, and the posterior is produced and truncated (fig. 3c); the
antero-lateral is in general narrower than the postero-lateral region, and the prominence of
the inter-ambulacral spaces in some individuals produces the sub-pentagonal varieties.
The base is very unequal from the convexity of the inter-ambulacra, which form five
nodulose eminences around ile mouth; the posterior single area in particular is extremely
prominent, gibbous (fig. 3 4, c), and much deflected ; its posterior border is truncated and
channelled to form the anal valley (fig. 3 ¢, d), which is bounded by two ridges, com-
mencing at the apices of the posterior pair of ambulacra, and passing downwards and
outwards towards the base, where they may be traced on the summit of the simgle area as
far as the mouth (fig. 3 4). The anal opening has a pyriform shape, with its apex directed
upwards ; it is situated in the upper part of the valley, nearly on a level with the dorsal
surface, and immediately below the ambulacral arch (fig. 3 d, ¢).

‘The ambulacral areas are all complete, at the dorsal surface they are on a level
with the inter-ambulacral plates, but at the base, they lie in depressions. ‘They are
of, unequal width, the single area being the narrowest, the posterior pair the widest,
and the anterior pair of intermediate breadth; the single area is straight, and the anterior

FROM THE INFERIOR OOLITE. 311

pair describe three curves in their course between the mouth and the disc (fig. 3 ¢);
the three anterior ambulacra converge nearly in the centre of the back, at the front,
and sides of the apical disc (fig. 3 a, 7). The posterior pair are somewhat wider than the
others, they curve gracefully round the single inter-ambulacrum (fig. 3 c), form an arch
round its produced and truncated border, and converge above the anal opening (fig. 3 d) ;
the ambulacral areas are formed of small plates, of which, on the dorsal surface, there are
four opposite one inter-ambulacral plate (fig. 3 e), but at the base there are only about
three m the same space (fig. 37). Each ambulacral plate is perforated at its outer side
with two very small pores, placed obliquely across the zones (fig. 3 e), which are narrow,
and observed with difficulty. Near the mouth the ambulacra widen, and the pairs
of pores are disposed in about three oblique series of three pairs in each (fig. 3 4); as
the plates are closely soldered together, their relation to the pores in this region is
very indistinct.

The inter-ambulacral areas are of unequal width; on the upper surface they are on
a level with the ambulacra, and with them form a uniform, convex back, but at the base
they are extremely prominent and nodulated; so much so, that the ventral is as
remarkable for its undulations as the dorsal is for the smoothness of its surface. The
single inter-ambulacrum differs from the others in being produced posteriorly, and
is extremely prominent and gibbous inferiorly (fig. 3 4, ¢).

All the plates are covered with minute, perforated tubercles, raised on uncrenulated
bosses, and surrounded by sunken areolas (fig. 3 g); the inter-tubercular surface is
‘so finely granulated that the tubercles appear conspicuous only when examined with a
lens. The tubercles are most numerous at the base; the spines are unknown.

The apical disc is a curious structure, it is composed of two pairs of perforated ovarial
plates (fig. 3 4, 7), disposed in pairs at some distance apart, and separated by three
largely developed ocular plates, which extend into the centre of the disc; the anterior
ovarials are of an irregular shape, and separate the single ambulacrum from the antero-
lateral ambulacra. On the surface of the right plate is the spongy, prominent,
madreporiform body ; behind and between them in the median line, is a small diamond-
shaped plate, its anterior angle unites with the apex of the single ambulacrum, and
its posterior border with the anterior ovarials; behind these are two rhomboidal-shaped
plates, which articulate before with the anterior ovarials, laterally with the apices of
the antero-lateral ambulacra, and behind with the posterior ovarial plates. Near the
points of junction of these plates with the ambulacra, the three small eyeholes are
situated, and behind the rhomboidal ocular plates the small, oblong, posterior ovarials are
placed. I have failed to discover ocular plates at the summits of the posterior ambulacra
in this species. The specimen which furnished these details has been mislaid, and could
not be found in time for the artist, but a very similar type of structure exists in
Collyrites ovalis (Pl. XXIII, fig. 2,7), where it is accurately drawn. The disc, it is
right to state, was studied with the microscope under an inch object-glass.

Al

312 COLLYRITES

The mouth is more or less sub-central, and lodged in a concavity formed by the
prominent nodulated inter-ambulacra. It is obscurely decagonal, and appears as if round ;
in some specimens it is much nearer the anterior border than in others. The mouth and
anus are nearly of the same size, and about one eighth of the length of the shell ; no traces
of jaws have yet been found, nor has the structure of the peristome been sufficiently
made out.

Affinities and differences—Many specimens of this urchin agree with M. Desor’s
figures of Disaster Hudesii, Agass., whilst others have the depressed dorsal surface,
and angular outline of D. ringens, Agass. As J have many series of intermediate forms
connecting these two extremes, I have referred them all to one species. On this
subject, M. Cotteau observes that he collected, with M. Moreau, from the “Oolite
ferrugineuse”” of Tour du Pré, a suite of specimens of D. rimgens; these presented
various degrees of tumidity and more or less circularity of outline; among them were
all the gradations conducting to D. Hudesiz, Agass., from this he concluded that the
urchin figured in his excellent work, and which may be taken as a fair representation
of many of our specimens, is a small and more elongated variety of D. rimgens, Agass.*
This conclusion, Professor Forbest admits, agrees with the experience of the collectors
of the Geological Survey.

Professor M‘Coy, in his memoir ‘On some new Mesozoic Radiata,’{ enumerates
D. Eudesvi as a British species from the Inferior Oolite of Dundry and Bridport, and has
described another form under the name D. sub-ringens. As he has favoured me with:
a sketch of this urchin, I can state with certainty that it is only a large individual of
D. ringens. The characters which Prof. M‘Coy regarded as specific, namely, the “ greater
gibbosity, and less prominence of the ridges on the under side,” and, the “ dispro-
portionate narrowness of the three anterior ambulacra, as in D. ringens,’”’ vary almost in
every one of the many individuals I have collected, I therefore do not hesitate to include
D. sub-ringens among the synonyms of Collyrites ringens, Agass., which is distinguished
from its congeners by the convexity of the basal portions of the inter-ambulacra, and
especially by that of its single inter-ambulacrum.

Locality and Stratigraphical position.—All my specimens have been collected from
the marly vein which traverses the upper ragstones of the Inferior Oolite of Dorsetshire,
in the zone of Ammonites Parkinson, Sow. From this stratum I have collected it
between Sherborne and Yeovil, at Burton Bradstock, Walditch Hill, and Chideock Hill,
near Bridport. It is generally associated with Collyrites ovalis, Leske, LTolectypus
hemisphericus, Agass., Clypeus altus, M‘Coy, and Stomechinus bigranularis, Lamck.

* “Htudes des Echinides Fossiles,’ p. 48.
+ ‘Memoirs of the Geological Survey,’ decade iii, pl. 9.

~

t ‘Annals of Natural History,’ 2d series, vol. ii, p. 420.

FROM THE INFERIOR OOLITE. 313

I have only seen one specimen (an oblong variety) which was said to have been found in
the Cornbrash, near Fairford (Gloucestershire). | Professor M‘Coy states that it is not un-
common in the Inferior Oolite of Leckhampton; but this is a mistake, as it is not within
the memory of any of our local collectors that any Collyrite has been found in the Inferior
Oolite of that: locality.

On the continent, it is found in the Marnes a Discoidées (Vesulien) cf Goldenthal,
Mont-Terrible, Salins, Besangon, Neufchatel, the Inferior Oolite (Bajocien) of Tour
du Pré (Yonne), and of St.-Vigor, Port-en-Bessin, Moutiers, Bayeux (Calvados).
It was collected by M. Triger, from the Forest Marble, Ass. No. 4, of his table, at
Pécheseul, Noyen, Saint-Pierre-des-Bois, Chemiré-le-Gaudin, département de la Sarthe,
where it is abundant.

History.—This species was recorded for the first time by Agassiz, in his ‘ Prodrome,’*
and it has been successively figured and described in his ‘Echinodermes Fossiles de la
Suisse,’ M. Desor’s ‘Monographie des Dysaster, M. Cotteau’s ‘Etudes des Echinides
Fossiles,’ ‘ Echinides du département de la Sarthe,’ and Professor Forbes’s ‘ Memoirs of the
Geological Survey.’ M. Desmoulins entered it in his ‘Tableaux Synonymiques des
Echinides.’ The history of this species is so intimately connected with its previous
description, that it is unnecessary to enter upon it further in detail under this head.

Cottyrites Ovauis, Leshe. Pl. XXIII, fig. a, 4, ¢, d, e, f, g.

Van Phelsum, p. 32, sp. 3 (Lgelschuitje twee-top) i.e., Echi-
noneus bivertex.

Knorr, Petrefactions, ii, p. 182, tab. © iii, No. 6.

D’Annone, Acta Helvetica, vol. iv, p. 275, sq.; tab. 14,

figs. 1, 2, 3.
D’Annone, Miner. Belust., v, p. 161, tab. iv, figs. 1, 2, 3.
SPATANGITES OVALIS. Leske, Additamenta Kleinii ad Disposition. Nat. Echinoderm., p.
253, tab. 41, fig. 5, 1778.
CoLLYRITES ANALIS. Desmoulins, Etudes sur les Echinides, p- 368, No. 14, 1837.
DISASTER ANALIS. Agassiz, Echinodermes Fossiles de la Suisse, ii, p. 6; pl. 1,
figs. 12—14, 1839.
DIsasTER AVELLANA. Agassiz, Catal. Syst. Ectyp. Foss., p. 3, 1840.
DISASTER BICORDATUS. Agassiz, Catal. Syst. Ectyp., Suppl., non Leske, non Goldfuss.
COLLYRITES ELLIPTICA. Desmoulins, Tableaux Synonymiques, p. 366, 1835.
DisASTER BICORDATUS. Desor, Monographie des Dysaster, p. 9, tab. 2, figs. 1—4, 1842.

— — Agassiz and Desor, Catalogue raisonné des Echinides, Annales
des Sciences Naturelles, 3"° série, tome viii, p. 31.
DiIsaSTER ANALIS. Desor, Monographie des Disaster, p. 10, pl. 2, figs. 8—10,
1842.

* «Soc. d’Hist. Nat, de Neufchatel,’ tome i, p. 168, 1836.

314

DISASTER AVELLANA.

— BICORDATUS.

DisastER ROBINALDINUS.

os SYMMETRICUS.

= AVELLANA.

= AGASSIZII.
CoLLYRITES BICORDATA.
— ANALIS.
—_— AVELLANA,
— AGASSIZII.

= BICORDATA.
—_ ANALIS.
= ANALIS.
= OVALIS.

COLLYRITES

Desor, Monographie des Disaster, p. 23, pl. 1, fig. 1—4, 1842.

Agassiz and Desor, Catal. rais. des Echinides, Ann. des Sc. Nat.,
3™° série, t. vil, p. 32, 1847.

Agassiz and Desor, Catal. rais. des Echinides, Ann. des Sc. Nat.,
3™° série, t. vil, p. 31.

Cotteau, Etudes sur les Echinides Fossiles, p. 73, tab. vii,
figs. 1—5, 1849.

M‘Coy, Annals of Natural History, 2d series, vol. ii, p. 415,
1848.

Agassiz, Catal. Syst., p. 3.

D’Orbigny, Prodrome de Paléontologie, t. 1, p. 289, No. 43,
1856.

Desor, Monographie des Dysaster, p. 23, tab. 1, figs. 1—4.

M‘Coy, Annals of Natural History, 2d series, vol. ii, p. 420,
1848.

Wright, Annals of Natural History, 2d series, vol. ix, p. 210,
1851.

D’Orbigny, Prod. de Pal., t. i, p. 318, No. 399, 1850.

Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 77,
1854.

D’Orbigny, Prod. de Pal., t. i, p. 290, No. 494, 1850.

D’Orbigny, Pal. Franc. Ter. Cretacés, t. vi, p. 49, 1853.

D’Orbigny, ibid., p.48, 1853.

D’Orbigny, ibid., p. 48.

D’Orbigny, ibid., p. 48.

D’Orbigny, Note rect. sur divers genres d’Echinides, Rev. et
Mag. de Zool., 2° série, t. vi, p. 27, 1854.

D’Orbigny, ibid., p. 27.

D’Orbigny, ibid., p. 27.

Desor, Synopsis des Echinides Fossiles, p- 206, 1857.

Cotteau, Note sur quelques Oursins de la Sarthe, Bull. de la
Soc. Géologique de France, 2° série, p. 649, 1856.

Cotteau et Triger, Echinides du Départment de la Sarthe,
pl. vii, figs. 7—9, p. 45, 1857.

Plaster moulds R15, R 16, type of bicordatus, Agassiz; Q 82, type of analis, X 76,

type of avellana.

Test thin, oval, anterior and posterior borders nearly uniform in convexity; sides
tumid; dorsal surface convex, sometimes flattened; vertex excentral, situated near the
anterior third; anal opening pyriform, supra-marginal ; postero-lateral ambulacra terminate
by the sides or immediately above the anus; base smooth, convex, without undulations ;
mouth-opening small, situated at the junction of the anterior with the middle third.

Dimensions.—Hight tenths of an inch; antero-posterior diameter, one inch and one
fifth ; transverse diameter, one inch and one tenth.

FROM THE INFERIOR OOLITE. o15

Description.—After a careful examination of all the evidence on the subject, I have come
to the conclusion that this is the urchin which was figured by Leske (tab. XLI, fig. 5), and
described by that author as Spatangites ovalis. The Ananchytes bicordata, Lamk. to
which it was formerly referred, is clearly the Spatangites bicordatus of Leske, and not the
8. ovalis of that author; the confusion occasioned by this mistake, prevails throughout all
the works which treat of the species, down to that of our friend M. Desor, in
which its true synonyms, with one exception, according to our ideas on the subject,
are given in his excellent ‘Synopsis des Echinides Fossiles’ The Spatangus ovalis of
Parkinson and Phillips is a Coral Rag urchin, and in my opinion is the Spatangites
bicordatus of Leske. I reserve further details on this question until I give the
description of the latter species.

M. Desor regards this urchin as an inflated variety of Dy eaten analis, Agassiz, and
preserves that author’s specific name; but surely, if we admit the identity of the
species, we should in justice to Leske retaim his specific name ovalis. On comparing our
urchins, however, with the very excellent figure given of D. Analis by M. Agassiz, I
confess I have never met with so depressed a form as that figured in the ‘ Hchinodermes
Fossiles de la Suisse ;’ moreover, there is always an elevation before the apical disc,
amounting in some individuals to a monstrosity, which does not exist in D. analis; the
posterior ambulacra, likewise, terminate at a greater distance before the anal opening than
in our specimens.

The regular oval outline of this urchin forms a striking contrast to the orbicular and
sub-pentagonal figures of Collyrites ringens ; the sides are tumid; the dorsal and lateral

surfaces are smooth, and convex ; and the test has a uniformly gibbous appearance, with a_

slight elevation on the upper surface; the ambulacra are all complete, passing, without
interruption, from the mouth to their terminations on the dorsal surface, and on the same
level as the inter-ambulacra; the three anterior ambulacra converge near the junction
of the anterior with the middle third of the back, and the apex of the single area is
separated from those of the antero-laterals by the anterior pair of ovarial plates; the
single ambulacrum is the narrowest, the postero-lateral are the widest; and the antero-
lateral of intermediate width; the anterior border is slightly flattened, and lies in a
depression in the centre of this region; the single area passes in a straight line from the
mouth to the vertex; the apex of this area rises into a small prominent triangular
eminence, which forms the highest point of the test, so that the vertex is situated at the
anterior third of the back (fig. 1 ¢), whilst in Collyrites ringens, it is at the posterior third.
The antero-lateral ambulacra (fig. 1 c¢), curve gently upwards, backwards, and
forwards, from the mouth to the apical disc, thereby forming an undulated course. The
postero-lateral pair take a long sinuous course from the mouth, passing backwards,
outwards, and upwards, over the posterior border, and terminate by making rather a sharp
curve at the upper end of the anal opening, or sometimes they form an arch immediately
over that aperture (fig. ] d); the point at which these areas terminate, in this species, is

~

316 COLLYRITES

an important guide to its determination, and this character is very accurately delineated in
Leske’s original figure of his Spatangites ovalis ; the apices of the postero-lateral ambulacra
converge on the back at the distance of three fifths of an inch behind the antero-lateral pair.

The poriferous zones are narrow, and im consequence of the depth of the ambulacral
plates the pores are wide apart; each plate is perforated with a pair of holes near its
lower border (fig. 1 e), and there are from two to three ambulacral plates opposite one
inter-ambulacral.

‘The pores are disposed in oblique pairs, they are very distinct on the sides and back
fig. 1 a, e, d), but are small and indistinct at the base (fig. 1 8).

The inter-ambulacral plates are large and bent, each plate forming a double inclined
(plane (fig. le). The anterior are much narrower than the posterior areas; they are
uniformly smooth and gibbous on the sides; the single inter-ambulacrum is bevelled
obliquely, and slightly flattened at the upper part of the posterior border; at the extreme
upper part of this region, and immediately beneath the centre of the arch formed by
the posterior ambulacra, the anal opening is situated (fig. 1 a,¢d). It has a pyriform
shape, with the apex directed upwards, and terminates between the apices of the posterior
ambulacra. From its sides two obtuse ridges pass downwards and outwards, which
sradually disappear about the middle of the area, near the anal opening; the tubercles are
larger, and set closer together, than at any other part of the upper surface (fig. 1 ¢).
The basal portion of the inter-ambulacrum is more gibbous and produced than the
corresponding parts of the other inter-ambulacra.

The base is convex, with little or no undulation ; anteriorly there is a slight concavity,

and posteriorly an increased convexity, occasioned by the gibbosity of the single mter-
ambulacrum (fig. 1 6, 7). ‘The small mouth-opening is lodged in a slight depression,
situated near the anterior fourth of the antero-posterior diameter of the test, but the
precise relative situation of this aperture appears to vary a little in different individuals.
The peristome is sub-pentagonal, and in one specimen, appears to have rudimentary
notches, which would imply that the Collyritide possessed jaws, but the organic evidence is
too feebly developed to enable me to state that such is unquestionably the case, unless
confirmed by a similar inequality of the margin in other specimens.

The apical disc is situated behind the sub-triangular vertex, and therefore occupies the
anterior third of the back; it has a lengthened rhomboidal figure, and is formed very
much like the disc of C. ringens, already described in detail. (See page 311.)

The single ocular plate is small, and occupies nearly the vertex, having behind it
the two anterior ovarial plates, which are situated between the single and the antero-
lateral ambulacra, the left plate being placed further forward than the right plate, which
supports the madreporiform body. Behind the anterior ovarial are the two large anterior
pair of ocular plates, and immediately behind them are the posterior ovarials (fig. 2 /).
The position of the posterior pair of ocular plates I have not ascertained; if they exist at
the summit of the posterior ambulacra, their true homological position, they are so

FROM THE CORAL RAG. 317

intimately soldered to the surrounding structures that I have as yet failed to detect them
with my compound microscope, provided with an inch object-glass; but the elements
of the disc are, in general, united so entirely to the adjoining plates of the test in the
Cotiyrivip#, that it is only in weathered specimens, or in those in which the shell has
passed into the condition of calcareous spar, that we can distinguish the separate pieces of
which it is composed. ‘The tubercles on the sides and upper surface are small, and
arranged in tolerably regular lines on the plates. There are, in general, three rows
on each plate (fig. 1 e); those at the base are larger (fig. 1 #), and more prominent ; they are
raised on prominent bosses, which are surrounded by areolas, and the intermediate spaces
are covered with close-set granules.

Afinities and dfferences.—The general outline of C. ovalis resembles C. ringens, but
is distinguished from it by the following characters. In C. ovalis, the highest point
of the back is near the anterior third, whilst in C. rzmgens, it is at the posterior third ;
in C. ovalis, the base is nearly uniformly convex, in C. rimgens it is very much undulated ;
in C. ovalis, the apical disc is situated near the anterior third of the back, whilst in
C. ringens, it is nearly central. The single inter-ambulacrum, likewise, is not so
much developed ; the anal opening is larger, and higher up, and the anal valley is more
rudimentary in C. ovadis than in C. ringens.

This species is distinguished from C. dicordatus, Leske, by the posterior ambulacra
always terminating in C. ovals at or near the apex of the anal opening, whilst in
C. bicordatus, the apices of these areas terminate at a point about one third of the
distance between the vent and the disc. The same character, the proximity of the
apices of the posterior ambulacra to the anal opening, serves to distinguish C. ovalis
from C. elliptica. C. ovalis resembles C. analis, but in the former they are nearer the
vent than im the latter. It is highly probable, however, that this is a mere variety, and
not a specific difference.

Locality and Stratigraphical position —I have ‘collected this species in the marly vein
which traverses the upper ragstones of the Inferior Oolite, in the zone of Ammonites
Parkinsoni, Sow., at Walditch Hill, near Bridport, where it was associated with Collyrites
ringens, and Holectypus hemisphericus. It has been found by Mr. Walton in the same
zone at Charleomb, near Bath, and by Dr. Bowerbank in the Cornbrash of Wilts, where
it is rare, as I only know of his solitary specimen from that formation.

fTistory.—First figured by Knorr, and afterwards figured and described by Leske as
Spatangites ovalis, m his edition of Klein’s ‘ Echinodermata,’ which figure was confused
with the Spatangites bicordatus of the same author. It was beautifully figured as
Disaster bicordatus by M. Desor, in his ‘Monographie des Dysaster;’ afterwards by
M. Cotteau under the name Disaster Robinaldinus, in his ‘ Etudes des Echinides Fossiles,’

318 COLLYRITES

and described under the name D. symmetricus, by Professor M‘Coy. It was recorded by
Professor Forbes as an abundant species, collected by the officers of the Geological Survey,
from several Inferior Oolite localities m Dorsetshire.

M. Desor enumerates the following localities where this species is found. Knorr and
Leske’s type specimens came from the Marnes a Discoidées (Vesulien) de Muttenz pres
Bale. It is found likewise in the Great Oolite (Bathonien) de Macon, de Bysé pres Caen,
la Latte prés Nantua (Ain), environs de Besancon, Véseloy (Yonne), Calcaire a Polypiers
(Bathonien) de Croisille, Charroux, and M. Triger collected it in abundance from the
Bradford Clay, Ass. No. 1, 2, and 3, of his table, and from the Forest Marble bed No. 1
at Monné, La Jauneliére, Tassé Champfleur, Petit-Oiseau, and several other localities in
the department of the Sarthe.

B. Species from the Coral Rag.
CoLLyritTEs BicorDATA, Leske. Pl. XXIII, fig. 2 a, 4,¢,d,¢e,f, 9, h.

Andreae Briefe aus der Schweiz, p. 16, tab. 2, fig. c, 1763-—
1776.
SPATANGITES BICORDATUS. Leske, apud Klein, Dispositio Naturalis Echinodermatum,
tab. 42, fig. 6, p. 244, 1778.

SPATANGUS OVALIS. Parkinson, Organic Remains, vol. iui, tab. 3, fig. 3, 1811.
SPATANGITES OVALIS. Young and Bird, Geology of the Yorkshire Coast, tab. 6, fig. 9,
p. 215, 1828.
SPATANGUS OVALIS. Phillips, Geology of Yorkshire, tab. 4, fig. 23, p. 127, 1829.
DISASTER OVALIS. Agassiz, Prodromus, Mémoires de la Soc. des Sc. Nat. de Neuf-
chatel, tome i, 1836.
COLLYRITES OVALIS. Desmoulins, Tableaux Synoptiques, p. 368, 1837.
DIsASTER PROPINQUUS. Agassiz, Echinoderm. Fossiles de la Suisse, part i, p. 2, tab. J,
figs. 1—13, 1840.
— OVALIS. Agassiz, Catalogus Systematicus ectyporum Echinodermatum
fossilium, p. 3, 1840.
— PROPINQUUS. Desor, Monographie des Dysaster, p. 14, tab. 3, figs. 24—26,
1844.
os TRUNCATUS. Dubois, Voy. au Caucase, (Ser. Geol.), tab. 1, fig. 1.

— a Desor, Monographie des Dysaster, p. 17; des Galérites,
tab. 13, figs. 8—11, 1844.

— — Agassiz and Desor, Catalogue raisonné des Echinides, Annales
des Sciences Naturelles, 3™ série, tome viii, p. 32, 1847.

— OVALIS. Agassiz and Desor, ibid.

— — Cotteau, Etudes sur les Bchinides Fossiles, p. 86, tabs. 8 and 9,
1849.

~~ — Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 213, 1851.

CoxtyritEs BIcoRDATA. Desor, Synopsis des Hchinides Fossiles, p. 204, 1857.

FROM 'THE CORAL RAG. 319

Test nearly oval, broader before than behind, upper surface convex, more or less
depressed ; sides rather tumid, front border slightly grooved, posterior border feebly
truncated, ambulacral areas of unequal width, posterior pair the widest, anterior ambulacral
summit nearly central, posterior situated nearly mid-way between the apical disc and the
vent ; base flat anteriorly and laterally, convex behind; mouth-opening small, circular,
situated at the anterior fourth of the base, tubercles small, placed at some distance apart,
three or four concentric rows on each large plate. Anal opening oval, situated in the
upper part of the posterior border, about midway between the ambulacral arch and the
basal angle.

Dimensions—a. Height, one inch and one twentieth ; transverse diameter, one inch
and nine tenths; antero-posterior diameter, two inches and one tenth. B. Height, one
inch and one twentieth; transverse diameter, one inch and three quarters ; antero-posterior
diameter, one inch and nine tenths. c. Height, eight tenths of an inch; transverse
diameter, one inch and four tenths ; antero-posterior diameter, one inch and a half.

Description.—It is rather remarkable that so much confusion should have arisen
regarding the only two Collyrites figured by Leske, and that a complete transposition of
his specific names should have been the result of this mistake. The urchin now under
consideration is, doubtless, the Spatangites bicordatus, Leske, which was erroneously
identified by Parkinson with the Spatangites ovailis, Leske, this formed the starting point
of the error, which has been faithfully copied by succeeding authors until corrected by
M. Desor, who has given, in his ‘ Synopsis,’ the correct synonymy of this species. A single
character, which has been well represented by Leske, determines this point, namely the
position of the posterior ambulacral summit, in Spatangites bicordatus it is between the
apical disc and the vent, whilst in Spatangitis ovalis it is immediately above the anal

The general form of Collyrites bicordata is nearly oval, the anterior half is more
enlarged than the posterior half (fig. 2 a, 4), the upper surface is uniformly convex
(fig. 2 c), and the base is flat (fig. 2 4, c), the anterior border forms the segment of a much
larger circle than the posterior border, and it has a median depression which extends to
the mouth in which the single ambulacrum is lodged (fig. 2 a), the sides are slightly tumid
and the posterior border feebly truncated, the greatest width of the test is behind the
antero-lateral ambulacra, from which point it gradually tapers backwards (fig. 2 a).

The ambulacral regions are of unequal width, the three anterior areas are about the
same diameter on the sides, but the posterior pair are one fourth larger, the single area is
the shortest; im specimen c it measures 1} inch, the antero-lateral 14% inch, and the
postero-lateral 14 inch in length from the peristome to the apical disc, the ambulacral
plates are narrow, and on the sides of the anterior pair there are from six to seven plates
opposite each large interambulacral plate (fig. 2 e); at the base they become much wider

A2

320 COLLYRITES

and are nearly half as deep as the inter-ambulacral plates (fig. 2 4). In the posterior pair
the plates on the sides are much deeper, for in these areas there are not more than two
or three plates opposite one large inter-ambulacral plate. The left postero-lateral
ambulacral area extends farther forward than the right.

The inter-ambulacral regions are large and of unequal width ; the antero-lateral areas
are the narrowest, the single area is of the same width, and the postero-lateral are one
third wider than the anterior pair ; the large pentagonal plates composing these areas are
bent in the middle, and there are from fifteen to sixteen pairs in each; the plates carry
three or four concentric rows of small tubercles (fig. 2 ¢), numbering from fourteen to
sixteen on each plate; the tubercles which are perforated are surrounded by well-defined
areolas, raised on crenulated bosses (fig. 2 g), and the inter-tubercular surface is crowded
with microscopic miliary granules (fig. 2 g) ; the basal are larger than the dorsal tubercles,
especially those situated on the prominent portion of the single inter-ambulacrum ; some
of these have wide hexagonal areolas, closely set together (fig. 2 4).

The poriferous zones are narrow ; in the anterior zones on the sides there are about six
pairs of pores opposite each large plate (fig. 2 e), whereas in the posterior zones in the
same portion of the test there are only three or four (fig. 2 d). At the base the pores are
small, very indistinct, and placed widely apart.

The base is flat at the sides and before, but is convex in the region of the single inter-
ambulacrum. As the basal portions of the ambulacral areas are nearly destitute of tubercles,
and the basal portions of the inter-ambulacral areas are furnished with larger tubercles,
the course of the former is readily made out by the comparatively naked track formed by
them, from the border to the mouth (fig. 2 4).

The small circular mouth-opening is situated in a depression at the anterior fourth of
the base, the peristome is entire, and there is no trace of notches nor of any armature
for the mouth (fig. 2 6).

‘The apical disc is placed rather nearer the anterior than the posterior border (fig. 1 a).
It has an elongated figure, but its elements are so intimately soldered together that their
relative anatomy is with difficulty made out. In most specimens the anterior ovarials
project between the single and the antero-lateral ambulacra (fig. 27) and the right plate,
which is the largest, supports the madreporiform body on the same line. Behind the
anterior ovarials the anterior pair of ocular plates are placed, and behind them come the
posterior pair of ovarials, with the single imperforate ovarial behind and between them ;
the small single ocular plate is seen at the apex of the single ambulacrum, but the position
of the posterior oculars I am unable to determine, notwithstanding the perfect con-
servation of one of my specimens.

The posterior border is slightly truncated; at its upper part, and nearly midway
between the basal angle and the apex of the posterior ambulacra, the anal aperture
is situated (fig. 2d). It is a small oval opening, the longest diameter of which is
in the direction of the longitudinal axis of the test. ‘The basal portion of the single

FROM THE CORAL RAG. 321

inter-ambulacrum is convex and prominent, more especially so nearest the border
(fig. 2 d).

Affinities and differences.—This species very much resembles Collyrites elliptica,
Lamk. From the Great Oolite and Kellovian strata of the Department of the Sarthe I
possess for comparison a very good series of this species, collected and sent me by my
friend, M. Triger, besides other good types from MM. Michelin, Bouchard, and Cotteau.
I find that in Collyrites bicordata the shell is more cordiform, and the anteal sulcus is well
developed, whilst in C. elliptica that depression is absent. The left postero-lateral
ambulacrum generally rises higher up on the dorsum than_the right postero-lateral
ambulacrum. ‘The anterior summit is rather more forward, and the basal portion of the
single inter-ambulacrum is more prominent than in C. elliptica; whilst in the relative
position of the mouth and vent, and the distance of the apices of the posterior ambulacra
from the latter opening, there is much similarity between these two species.

Locality and Stratigraphical position.—The Yorkshire specimens have been collected
from the lower calcareous grit, near Scarborough; they are in general denuded of their
test, and are mostly deformed. C. W. Strickland, Esq., has collected several specimens in
the Coralline Oolite of Hildenley, where they are associated with Cidaris florigemma, Phil.,
Hemicidaris intermedia, Flem., and Pseudo-diadema hemisphericum, Agas. James Carter:
Hsq., of Cambridge, has collected this species from blocks of Oolitic drift at Holywell,
St. Ives, the rock containing these specimens is a ferruginous, coarse-grained oolite, which
I suppose may have been derived from the base of the Coral Rag, or lower calcareous grit.
This gentleman has likewise obtained fine specimens of the same species at Ely, from a
rock which he conjectures to be Kimmeridge clay. One of these urchins is figured in PI.
XXIII, fig. 2. It is unfortunate that a doubt should still exist relative to the true age of
these beds, and I feel under many obligations to Mr. Carter, which it affords me great
pleasure to acknowledge, for the series of specimens of C. dicordatus he has kindly
communicated and generously given me. Professor Sedgwick has likewise been most
obliging in making an examination of one of these specimens, and in expressing his opinion
relative to the age of the Oolitic drift at Holywell, containing C. dzcordatus. I have much
satisfaction in adding that distinguished geologist’s opinion on the subject, which accords
with my own conjectures made from a paleontological and not from a stratigraphical point
of view:

“T have no doubt,’ says Professor Sedgwick, in a letter to me on the subject,
“the specimen is what is commonly called our glacial drift, not, however, a drift
brought on icebergs, but a drift caused by a great change of level about the end of
the so-called glacial period, and it contains fragments innumerable of rocks belonging
to the whole series, from the lias to the chalk inclusive. Our general order of
super-position round about Cambridge is, Ist, gravel and drift of different ages, irregular

322 COLLYRITES.

im thickness, and capping all the other deposits in a disorderly manner, without absolute
continuity. 2d, chalk. 3d, upper-green-sand—very thin, but full of fossils, and now
worked much for the phosphatic nodules called (by mistake) coprolites; 3 a, galt 3 4,
lower-green-sand resting, with some discordance on the beds below. It is seen in one
place resting on good Kimmeridge clay, in another immediately on Oxford clay. 4th,
Kimmeridge clay. 5th, Coral rag, or Middle Oolite—no Portland Oolite in this country.
The Coral rag is not continuous, and is only well! seen in one spot, but it may exist in other
places under the drift which conceals so many of our strata. 6th, Oxford clay.

“The lower Oolitic terrace, including everything from Cornbrash to Inferior Oolite, is
far removed from us.

“There are good brick-pits in the upper part of the Oxford clay, and immediately
over the clay are some stone bands, which may possibly represent the base of the Coral
rag. My belief is that your fossil (Collyrites bicordata, Leske,) has been drifted out of
the Coral Rag or Middle Oolite, which will agree well with your idea of the true place of
this species.”

The foreign distribution of this fine species is, according to M. Desor, from the Terrain
a Chailles, or Inferior Corallian, equivalent to the lower calcareous grit of English geolo-
gists ; in the Swiss Jura, it is found in that stage at Fringeli, Liesberg, Wahlen, Delémont,
Porrentruy ; of the Salinois Jura, at Mont Bregille, near Besancon. It is collected in the
same stage in France, according to M. Cotteau, from the “ Calcaires Oxfordiens ” of Lucy-
le-Bois, Villiers-les-Hauts (Yonne).

323

NOTES

On Fortien Jurassic species of COLLYRITID AI nearty atuiep To Britisn FrorMs,
BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITES.

Disaster GRANULOSUS, Minster. Syn. Nucleolites granulosus, Goldf., tab. xliii, fig. 4.

Test small, elongated, obovate, convex on the upper surface, flat on the under side,
rounded before, and obliquely truncated behind; anterior ambulacral summit excentral,
nearer the anterior border ; posterior ambulacra much arched over the vent; tubercles
numerous, irregularly scattered over the surface; granules, small, numerous, close-
set.

Dimensions.—Height, three quarters of an inch; breadth, one inch and one eighth;
length, one inch and three tenths.

Formation.—Oxford-gruppe, (Oppel.) Amberg, Streitberg, Bavaria.

Collections.— British Museum, Continental collections. My cabinet. Common.

DIsasTER ANASTEROIDES, Leymerie. Syn. Disaster anasteroides, Cotteau, Hchinides
Fossiles, tab. xlvi, figs. 4—10.

This Disaster closely resembles the preceding species, but is larger and less
cylindrical than it.

Dimensions.—Height, seven tenths of an inch; breadth, one inch; length, one inch
and four tenths.

Formation.—Kimmeridge of Bar-sur-Aube.
Collections.—M. Leymerie, M. Cotteau.
Disaster Morscau, Desor. Syn. Disaster Moeschii, Cotteau et Triger, Echinides du
Département de la Sarthe, Pl. XIV, figs. 9—11, p. 51.

Test elongated, sub-cylindrical, enlarged and rounded before, truncated obliquely, and

324 FOREIGN JURASSIC COLLYRITID A.

square behind; upper surface convex, base flat; ambulacra narrow; anterior summit
removed to a considerable distance from the posterior summit; apical disc small, square,
vent pyriform, supra-marginal; peristome extremely excentral.

Dimensions—Height, six tenths of an inch; breadth, seven tenths; length, one
inch.

Formations.—Great Oolite, Saimt-Marceau, (Sarthe), Btage, Callovien, Hornussen,
Kornberg (Argovia), Erlinsbach, and Pouillerel, near Chaux-de-Fonds,
Switzerland.

Collections —MM. Guéranger, Moesch, Cartier, Nicolet, Mus. Neuchatel. Rare.

CouLyRiTES ELLIPTICA, Lamk. Syn. Disaster ellipticus, Desor. Monographie des
Disaster, tab. ui, figs. 5—7.

‘Test regularly elliptical, convex above, more or less depressed, plano-convex below ;
the apices of the posterior ambulacra converge at a point about one third of the distance
between the vent and the anterior summit, which is more or less excentrally forwards.

Dimensions.—This species varies very much in size and relative dimensions, the
following is M. Cotteau’s estimate from abundant materials :—<a.
Circular variety—Height twenty millimetres; transverse diameter,
forty millimetres; antero-posterior diameter equal to the transverse.
B. Hlongated variety.—Height twenty-three millimetres; transverse
diameter, thirty-eight millimetres ; antero-posterior diameter, forty-two
millimetres. c. Large variety—Height forty millimétres ; transverse
diameter, sixty millimetres; antero-posterior diameter, sixty-three
millimetres. (This is the Disaster malum, Ag.)”

Formation.—Kellovian, Chaufour, Mamers, “‘ Kelloway Ferrugineux.” (Sarthe.)

Collections.—Very common in most collections. I have a fine series in my cabinet,

sent by M. Triger, M. Cotteau, and M. Michelin, from this locality.

CoLLyRitus pInGvis, Desor. Synopsis des Hchinides Fossiles, p. 205.

‘Test depressed, of an elliptical form, with the border inflated, resembling C. dicordata a
little, but larger than that form; posterior ambulacra nearly straight and rising much
higher than the vent.

Formation.—Oxfordian superior of Bétzberg, and Geisberg, near Brugg (Argovia).

Collections.—Mus. Bale, Coll. MM. Gressly, Schmiedlin, and Cotteau.

FOREIGN JURASSIC COLLYRITIDA. 325

CoLLyritEs ORBIGNIANA, Cotteau. Echinides Foss. Pl. IX, figs. 3—5.

Test oval, cordiform, upper surface inflated, under surface flat ; the posterior ambulacra
ascend in nearly a straight direction, and meet above the vent.

Dimensions.— Height, three quarters of an inch; breadth, one inch; length, one inch
and one twentieth.

Formation.—Oxford-clay of Stingy, (Yonne). Rare.

Collection.—D’ Ormois.

Coxtyrires Lory, Albin Gras. Catal. des Foss. de l’Isére, tab. ii, figs. 1—3.

Test elongated, contracted behind ; the posterior ambulacra rise high up on the dorsal
surface, as in C. dzcordata, but the ambulacral areas are narrower.

Formation.—Corallian d’Kchaillon (Isére). Rare.

Collection.—M. Albin Gras.

Cotryrites Desorrana, Cotteau. Echinides Foss. Pl. XX XIX, Tee

Test large, oval, or sub-elongated ; anterior border with an anteal sulcus; posterior
border obtuse ; convex and depressed on the upper surface, flat on the under surface ; the
three anterior ambulacra narrow, anterior pair flexed; summit nearly central; posterior

ambulacra converge at a considerable distance above the vent.

Dimensions — Height, thirty-three millimétres; breadth, seventy-four millimetres ;
length, eighty-seven millimétres=three inches four tenths. Cotteau.

Formation.—Inferior Corallian of Chatel-Censoir, and Druyes, (Yonne).

Collection.—M. Cotteau ; known only as a siliceous mould, and in general deformed.

326 FOREIGN JURASSIC COLLYRITID A.

Connyrires casTaNnga, Desor. Synopsis des Hchinides Fossiles, p. 207.

“Test very much inflated, short, almost spherical, contracted and sub-rostrated pos-
teriorly ; posterior ambulacra much arched, and converging immediately above the vent,
which is only visible below ; inferior surface convex and undulated ; the ambulacra repose
in depressions, and the inter-ambulacra form convexities between them ; the single inter-
ambulacrum is very prominent.’ Desor.

Formation.—** Kellovien de St.-Croix, de Poillerel pres Chaux-de-Fonds. Pas trop
rare.”

Collections.—‘‘ Mus. Neuchatel, coll. of MM. Campiche, Nicolet.” Desor.

Connyrites Vonrast, Agass. Syn. Disaster Voltzii, Agassiz. Echinodermes Foss. de la
Suisse, tab. iv, figs. 11—13. Desor, Monogr. des Disaster, tab. i, figs. 18 —21.

Test large, circular, depressed, convex above, flat below; posterior ambulacra very
much arched and converging above the vent, which is large, pyriform, and infra-marginal ;
mouth-opening central; peristome circular ; base nearly flat, and only slightly cushioned ;
the ambulacra lie in depressions, and the inter-ambulacra form inconsiderable convex
prominences ; the ambulacra are all equal in width, and there is no anteal sulcus; the
pores are closely approximated, and form double rows near the peristome.

Formation.—“ Oxfordien des Voirons prés Genéve. (Voltz).”

Collection—Museum of Strasbourg. Very rare; only two specimens known, both
of which are in this Museum. One of them measures 34 inches in

diameter.

CoLLyRITEs TRANSVERSA, d’Orbigny. Paléontologie Frangaise Ter. Crétacés. p. 50.

A large species, sixty-one millimétres in breadth. Under this name M. d’Orbigny
notices a cordiform species, the length of which is only nine tenths of its breadth, and is
as high as it is long. his species is remarkable for its transverse form, its nearly round
figure, and deep anteal sulcus.

FOREIGN JURASSIC COLLYRITIDA. 327
Formation —* Du 12° étage Callovien des environs d’Escragnolles (Var.)”

Collection.—M. d’Orbigny.

Cottyrites carinatus, Leske. Syn. Spatangites carinatus, Leske, apud Klein, tab. 51,
figs. 2,3. Goldfuss, Petref. Germ., tab. xlvi, fig. 4.
Desor, Disaster, tab. iii, fig. 1.

Test small, inflated, cordiform; with an anteal sulcus, and a carina or ridge more or
less marked, which extends from the middle of the upper surface to the vent. Base
convex and cushioned, single inter-ambulacrum very prominent at the base, anal opening

marginal.

Formation.—Oxfordien de Gunsberg (Cant. de Soleure). Oxfordthon ; Thonkalke mit
Terebratula impressa, Weisser, Jura (a). (Oxfordian.) Quenstedt.

CoLLyRiTEs CAPIsTRATA, Desmoulins. Syn. Spatangus capistratus, Goldfuss, Petref. Germ.
Agassiz, Echinid. Foss., tab. iv. Desor, Disaster,

tab. 11.

Test cordiform, rounded anteriorly, with an anteal sulcus, tapering behind, and inflated
at the sides, without a dorsal carina; vent in the middle of the posterior border ; postero-
lateral ambulacra rise high up on the dorsal surface and converge at a point realy
equidistant from the anterior summit and the vent.

Dimensions.—Height, seven tenths of an inch; breadth, one inch; length, one inch
and one fifth.

Formation.—Corallien inférieur d’Urach, (Wiirtemberg), de Porrentruy, Ste. Croix.
Weisser, Jura a@ (Oxfordian). Quenstedt. Wirtemberg.

Collections.—Museums Neuchatel, Bale, British. Abundant.
Contyrites excentrica, Minst. Syn. Neucleolites excentricus, Goldfuss, Petr. Germ.,
tab. xlix. Desor, Disaster, tab. iv, figs. 1—3.
Test small, nearly circular, or elliptical, abruptly truncated posteriorly ; posterior

ambulacra converge above the vent, which opening is high up towards the dorsal surface.
A3

328 FOREIGN JURASSIC COLLYRITID 4.

Formation.—Jurassic limestone near Kehlheim ; age not determined.

Collection.n—Museum at Munich, coll. Count Minster.

Counyrites FAzBA, Desor. Synopsis des Hchinides Fossiles, p. 209.

“Test small, intermediate in form between C. capistrata and C. bicordata, Leske,
less triangular than the former, but more contracted behind; posterior ambulacra
converge at some distance above the vent, which is nearly entirely visible above.”

Formation.—* Kellovien d’Ueken, pres d’EHffingen (Argovie).”

Collection.—‘‘ Moesch ; very abundant.” Desor.

Meraporuinus Micurninit, dgass. Michelin, Revue et Mag. de Zool., No. 8, 1854.

Cotyrites Micuetinu. Cotteau, Echinides Foss., pl. xl, fig. 5.

“A large species, rounded before, truncated behind; the anterior summit very
excentral, and occupying the most elevated part of the test, which is prolonged forwards
in the form of a rostrum.”

Formation.—‘ Corallien (Calcaire a chailles) de Druyes et Chatel-Censow (Yonne).”

Collection —“ MM. Michelin, Cotteau.” Desor.

= i" . eel .
METAPORHINUS CENSORIENSIS, Desor. Synopsis des Hchinides Fossiles, p. 211.

CoOLLYRITES CENSORIENSIS. Cotteau, Echinides Foss., pl. xl, figs. 6, 7.

This singular urchm resembles the preceding species; according to M. Cotteau,
it is more inflated, and rounder before, but not so much sloped behind; the posterior
ambulacra are more flexuous and unite nearer the vent.

FOREIGN JURASSIC COLLYRITID A. 329
Formation.—Corallien of Chatel-Censoir, (Yonne).

Collection.—M., Cotteau, a single specimen ; a plaster mould in my cabinet.

Grasia ELONGATA, Michelin, Revue et Mag. de Zool., No. 8, 1854.
Hyszoctypus nLoneatus. Albin Gras, Cat. des Fossiles de l’Isére, tab. ii, fig. 1—3.
A large urchin, very much elongated, measuring seven centimetres in length, by four

in breadth ; the anterior ambulacral summit very near the anterior border ; the posterior
ambulacra meet high up on the dorsal surface near the middle of the test, and at a

considerable distance from the vent.
Formation.—Corallien d’Echaillon (Isére) ; very rare.

Collection.—Dr. Albin Gras.

330

Family 9.—ECHINOBRISSIDA, Wright, 1856.

Famille des CASSIDULIDES, groupe des NucLEOLIDES, Agassiz and Desor, 1846.
Famille des NUcLEOLIDEES (in pars) Albin Gras, 1848.
Famille des HCHINOBRISSIDEES (in pars) D’ Orbigny, 1855.

The family Ecutnosrissipa, as I have defined it, comprehends only those urchins
which have petaloidal or sub-petaloidal ambulacra; the vent lodged in a dorsal sulcus,
or opening at the posterior border; the mouth edentalous ; and the peristome pentagonal
and sub-central.

The test, in all the smaller species, is thin, has a sub-quadrate, oblong, sub-pen-
tagonal, circular, or clypeiform shape; is uniformly covered with small imperforate
tubercles, raised on uncrenulated bosses, and surrounded by deep sunken areolas (Pl. XXIV,
fig. 1 2); the spines are small, short, and slender (Pl. XLI, fig. 1); the tubercles at the
base are always larger, and more fully developed, than those on the upper surface.

The ambulacral areas are narrow and lanceolate; they are enclosed by poriferous
zones of unequal width, the pores being placed more or less wide apart in different
regions of the zones ; the holes of the mner row are circular, those of the outer are oblong
or slit-like, and they often communicate with the inner series by transverse sulci. In
consequence of this structure, the ambulacra present elegant petaloidal forms, more or less
developed in different species, but always lanceolate above, expanded in the middle, and
contracted and open below. ‘The poriferous zones at the border and base are narrow,
and the pores are small, equal, and placed wide apart (P]. XXIV, fig. 1 2).

The apical disc is in general small, and composed of at least ten elements ; of the five
genital plates, four are perforated, and one is imperforate; the right antero-lateral plate is
always the largest and carries the madreporiform tubercle, which is often very large, and
nearly conceals the other elements of the disc; the five ocular plates are small, with
marginal orbits (Pl. XXIV, fig. 1 g), placed opposite the apices of the ambulacra.

‘The vent is large, and in general opens into a valley situated in the upper surface of
the inter-ambulacrum, or at the middle or margin of the posterior border; in the only
living species at present known, MVucleolites recens, Wdwards, from New Holland, figured in
the illustrated edition of the ‘Régne Animal,’ this aperture is found to be closed by a series
of small plates, in the same manner as the anal aperture is filled up in the Ecnin1pm and
Sparancip#. I have copied this figure in Pl. XLI, fig. 1 a, and a specimen of the urchin,
without spines or anal plates, is now in the collection of living Echinoderms in the British
Museum.

The mouth-opening is small, sub-central, and edentulous; the peristome in general is
pentagonal, and in the genus Clypeus is surrounded by five oral lobes (Pl. XXVIII, fig.
1 2),

ECHINOBRISSUS. 331

The inter-ambulacral areas are wide ; the plates composing these portions of the test
are large, and bent in the middle; each plate supports about three rows of small tubercles,
which are arranged in lines, with much regularity (Pl. XXXII, fig. 1 ¢).

The Ecnrosrisstp® have many organic characters in common with the Ecurno-
LAMPID#, but they are distinguished from that family by the position of the vent, and by
the absence of the poriferous petals which in the latter surround the mouth.

The Ecurvoprissip&, thus limited, nearly corresponds with the group of Nucléolidées
in the family CassipuLens of Agassiz and Desor; it differs from the family Nuctzo1irip a
of Dr. Albin Gras, and the family Kcuinosrissip# of M. d’Orbigny, by the elimination
of all the urchins therefrom which have a basal vent, peristoma] lobes and petals, and an
organization in accordance with the genus Hchinolampas.

Genus—ECHINOBRISSUS, Breynius, 1732.

Nuciteouites, Lamarck, 1801.
— Goldfuss, 1826.

— Agassiz, 1837.
Ecuinosrissus, D’ Orbigny, 1855.
— Desor, 1857.

— Cotteau, 1858.

This natural group is composed of small urchins, which have an oval, oblong, sub-
quadrate, or sub-circular form, more or less convex on the upper surface, and slightly
concave beneath ; the test is rounded anteriorly, more or less produced, truncated, or
lobed posteriorly, and is in general narrow before, and wider behind; the vent opens in
the upper surface into a dorsal valley, which in one section extends from the apical disc to
the posterior border, and in another is limited to the lower half thereof; the aperture is
closed by a series of small anal plates, which are usually absent in fossil species, but are
preserved in the only living example of the genus at present known (Pl. XLI, fig. 1).

The base is more or less concave; the small mouth-opening is excentral, and
lodged in a depression, nearer the anterior than the posterior border; the peristome in
many of the species is regularly: ‘pentagonal, in others it is oblique. M. d’Orbigny* has
separated the latter into a distinct genus, under the name Zrematopygus, but these oblique-
mouthed species can at most be considered only as a section of the genus Lehinobrissus :
which are supposed to be special to the Cretaceous Rocks.

The apical disc is small, square, and compact; it is composed of four perforated
genital plates, arranged in pairs, and one single imperforate plate; the right antero-
lateral is the largest, and supports the madreporiform ptubercle ; the five small

* ©Paléontologie Francaise Ter. Cretacés,’ tome vi, p. 374.

302 ECHINOBRISSUS

ocular plates are triangular, and oceupy depressions between the larger genital plates,
opposite the summits of the petaloid ambulacra.

The tubercles are small on the upper surface, and larger at the base.

The genus Hchinobrissus was established by Breynius in 1732, in his important
memoir ‘ De Echinis et Echinites,’ in which it was thus characterised : “ Hehinobrissus est
Eichinus, cujus oris apertura centrum basis fere occupat, ant vero im vertice conspicitur,
a centro aliquantulum remota, et in sinu quodam ori oblique opposita.”*

Klein, who published two years afterwards, unfortunately did not preserve any of the
well-defined genera of his learned contemporary, and his commentator, Leske, in 1778, placed
the Echinobrissus of Breynius among the Spatangus of Klem. When Lamarck, in 1801,
instituted his genus /Vucleolites, he appears not to have been aware that the same group
had been well figured and accurately defined sixty-nine years before by Breynius;
in his great work, “‘ Animaux sans vertébres,” he reproduced his genus Nucleolites, and
for the first time refers to Breynius’s work for figures of the species.

M. Agassiz, in dismembering Lamarck’s Nucleolites, did not restore Breynius’s genus,
although that author was most careful to reproduce the genera established by the older
authors ; thus, WVwcleolites columbaria, Lamk., was repeated as the type of his new genus
Catopygus, and IV. ovalus, Lamk., became the type of Pyrina, whilst WV. scutatus,
Lamk., remained the type of JWVucleolites. M. d’Orbigny restored the genera so
well established by Breynius, and proved beyond all question that author’s claim to
Echinobrissus ; M. Cotteau and M. Desor have both admitted the justice of his views,
and the genus Hchinobrissus now occupies the position from which it ought never to have —
been displaced.

A. Species from the Inferior Oolite.

HcHINOBRISSUS CLUNICULARIS, Lihwyd. Pl. XXIV, fig. 1 a, 6, ¢, de, f, g, h, 2, h.

ECHINITES CLUNICULARIS. Llhwyd, Lithophylacii Brittanici Ichnograph., p. 48, 1698.

EcHINOBRISSUS PLANIOR. Breynius, Schediasma de Echinis, tab. vi, figs. 1, 2, 1732.
Nucitreonites SOWERBYI. Defrance, Dic. Sciences Naturelles, tome xxxv, p. 213, 1825.
CLYPEUS LOBATUS. Fleming, British Animals, p. 479, 1828.
— CLUNICULARIS. Phillips, Geology of Yorkshire, tab. vii, fig. 2, 1829.
NUCLEOLITES CLUNICULARIS. Blainville, Dic. Sciences Naturelles, tome lx, p. 188, 1830.
— LATIPORUS. Agassiz, Echinoderm. Foss. de la Suisse, p-. 43, tab, vil,
figs. 13—15.
— “=~. cnuntcuLarts. Desmoulins, Tableaux Synonymiques des Echinides, p. 358,
1837.
a a

* «De Echinis et Echinites, sive Methodica Echinorum Distributione, Schediasma,’ 1732.

FROM THE INFERIOR OOLITE. 333

NUCLEOLITES CLUNICUNARIS.

- TERQUeMI.

_ THURMANNI,
— PYRAMIDALIS.
a CLUNICULARIS.
— EDMUNDI.

— CONICUS.

— CLUNICULARIS.

ECHINOBRISSUS CLUNICULARIS.

— TERQUEMI.

— LATIPORUS.

— THURMANNI.
= CLUNICULARIS.

— TERQUEMI.

— LATIPORUS.

— SARTHASENSIS.
— CLUNICULARIS.
— CONICUS.

— EDMUNDI.

— THURMANNI.
—_ CLUNICULARIS,

NUCLEOLITES CLUNICULARIS.

— SARTHASENSIS.
AGASSIZ MOULDS.

Dujardin, in Lamarck’s Animaux sans vertébres, 2° ed., tome iii,
p. 345, 1840.

Agassiz, Catalogue raisonnée des Echinides, Revue et Mag.,
1847.

Desor, Catalogue raisonnée des Echinides, Annales des Sciences
Naturelles, 3° série, tome vii, p. 154, 1847.

M‘Coy, Annals and Magazine of Natural History, 2d series,
vol. ii, p. 116, 1848.

Forbes, Memoirs of the Geological Survey, decade 1, pl. ix,
1849.

Cotteau, Echinides Fossiles, p. 67, tab. v, figs. 1—3, 1850.

Cotteau, Echinides Fossiles, p. 64, tab. iv, figs. 4—6, 1850.

Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 297, 1851.

Bronn, Lithaea Geognostica, 3° auflage, Band. ii, p. 152,
1852.

Guéranger, Essai d’un rept. Paléont. de Ja Sarthe, p. 25, 1853.

Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 84.
1854.

D’Orbigny, Note rectif. sur divers genres d’Echinides, Rev. et
Mag. Zool., 2° série, t. vi; p. 24, 1854,

D’Orbigny, ibid., p. 24, 1854.

Thid.

Ibid., p. 25, 1854.

Desor, Synopses des Hchinides Fossiles, p. 263, pl. xxx,
figs. 18—20, 1857.

D’Orbigny, Paléontologie Francaise Ter. Cretacés, t. vi, p. 390.

Ibid., p. 391, 1857.

Ibid. of ep

Ibid. Rs '

Ibid. , ér

Ibid. ribiaee ee

Ibid. 3 BS

Cotteau and Triger, Echinides de depart. de la Sarthe, pl. x,
fig. 7, p. 12.

Pictet, Traité de Paléont., t. iv, p. 217, Atlas, pl. xciv, fig. 10,
1857.

D’Orbigny, Prodrome de Paléontologie, tome i, p. 220, 1858.

P. VII, type. T.LXXXIII, Nucl. Terquemi. S. XLVI, Nucl.
latiporus.

Test sub-quadrate, anterior border rounded, posterior bilobed ; dorsal surface convex,
declining abruptly anteriorly, more gently posteriorly ; apical disc and vertex sub-central ;
ambulacral areas narrowly lanceolate above, converging below; dorsal valley deep,
lanceolate, extending to the posterior border of the apical disc; posterior lobes gently
tapering, not tumid; base concave and grooved by the ambulacra; mouth-opening sub-
pentagonal, situated nearer the anterior border.

334 ECHINOBRISSUS

Dimensions.—Large Cornbrash specimen (fig. 1 &). Height, eighteen twentieths of an
inch; anterior posterior diameter, one inch and thirteen twentieths; length from the
border to the posterior sulcus, one inch and eleven twentieths ; breadth across the apical
disc, one inch and eight twentieths.

Cornbrash specimen (fig. 1 a).—Height, eight tenths of an inch; antero-posterior
diameter, one inch and one quarter of an inch; transverse diameter, one inch and one
quarter of an inch.

Inferior Oolite specimen.—Height, six tenths of an inch; antero-posterior diameter,
one inch and three tenths of an inch; transverse diameter, one inch and three tenths of an
inch.

Description.—This is doubtless the:urchin to which Llhwyd* gave the name Lchinites
clunicularis, and described ‘ Kchinites é lapide selenite, quinis radiis € duplice serie trans-
versarum lineolarum conflatis,” he refers to the figures in Plott + and Lister, + but as these
exhibit no anal valley, it is impossible to say whether they represent this species or the
Coral Rag form. ‘The figure given by Breynius,} and described as Hchinobrissus planior,
represents this species as shown by the length of the anal valley, which reaches as high as
the disc, whilst Hchinobrissus elateor, fig. 3 of the same plate, represents H. scutatus from
the Coral Rag. This most acute observer had therefore clearly distinguished and figured
a diagnostic specific character which has been overlooked by subsequent authors, and led
to much confusion in the synonyms of /. clunicularis. Spatangus depressus, of Leske, ||
most probably represents a large quadrate variety of #. scutatus, and is consequently
omitted from our list of synonyms. Dr. William Smith figured in his plate of charac-
teristic Coral Rag fossils an urchin to which he gave no name. ‘This Fleming** refers to
EF. clunicularis, whilst he calls 2. lobatus the species figured by Lister, forgettimg that
Lihwyd referred to Lister’s figure as-the type of H. clunicularis. Professor Phillipstt
distinguishes the two species from each other, and restricts the name ZH. clunicularis to the
Cornbrash form, whilst he figures the Coral Rag nucleolite as 7. dimidiatus. Continental
authors have made several species out of the simple varieties of . clunicularis ; but when
we recollect the many varieties of figure and outline which this urchin exhibits, any
erroneous multiplication of species is readily explained.

Professor Edward Forbes} { considered &. scwtatus, Lamk., a variety of 2. clunicularis.
This error, however, he afterwards corrected, when he became acquainted with the true

* ¢Lithophylacii Britannici Ichnographia,’ p. 48, No. 988.
+ ‘History of Oxfordshire,’ table ii, fig. 12, 1698.
t ‘De Lapidibus Turbinatis,’ cap. 11, titulus xxvi, 1678.
§ ‘Schediasma de Echinis,’ tab. vi, figs. 1, 2.
|| ‘Dispositio Naturales de Echinodermatum,’ tab. li, figs. 1, 2.
{ ‘Strata Identified by Organized Fossils.’
** ¢ British Animals.’
+t ‘Geology of the Yorkshire Coast.’
ft ‘Memoirs of the Geological Survey,’ decade i, pl. ix.

FROM THE INFERIOR OOLITE. 335

types of Lamarck’s species. In fact, Hehinobrissus clunicularis, Lihwyd, may be regarded
as the type of that section of nucleolites in which the anal valley extends from the border
to the apical disc, and Fehinobrissus scutatus, Lamk., of that smaller section in which
the anal valley never extends from the border to the disc.

Professor M‘Coy* described three nucleolites under the names planulatus, pyramidalis,
and egualis. The two latter forms appear to be varieties of 2. clunicularis, and planulatus
a variety of #. scutatus. I have not seen the original specimens which belong to the
Cambridge Museum; but the author having kindly furnished me with outlines of these
urchins to assist me in identifying his species, I have formed that opinion from his
figures.

This urchin exhibits much diversity as regards size, outline, height, and tumidity. Its
most typical forms are found in the Inferior Oolite and Cornbrash, and one of the best
specimens I know is that from the cabinet of my friend, the Rev. A. W. Griesbach, which
forms the subject of our figure. The suite of specimens before me from these ferrains vary
from a sub-orbicular to a sub-quadrate outline, and present nearly all the intermediate forms.
‘They are rounded anteriorly, a little contracted before, enlarged at the sides, and more or
less bilobed posteriorly. The upper surface is convex, and exhibits various degrees of
elevation ; in some it is much depressed, in others it rises into a sub-conical form. Ina
series of specimens before me scarcely two have the same proportional height. The vertex
is almost always excentral and inclined towards the anterior border; but the amount of
inclination, like the height, varies considerably in different individuals.

The ambulacral areas have a petaloid or lanceolate figure, with sub-parallel sides ; the
single area and the anterior pair are nearly of the same length and width, and the
posterior pair are the longest and widest (fig. 1 a, c). The poriferous zones vary in
structure on the dorsal and ventral surfaces ; in the petaloid portion of the dorsal surface
the pores of the inner row are round, those in the outer row are oblong, and the furrow
uniting the pores varies in depth in different examples (fig. 17); in a large specimen
there are about forty pairs of pores in the petaloid portion of the dorsal zone; between
each pair there is a short row of small microscopic granules which separates the outer
oblong pores from each other (fig. 1 f). In all the non-petaloid portion of the zones, the
pores are small, round, and very indistinct (fig. 1 e); at the sides and outer third of the
base, near the mouth, however, they become more distinct.

The inter-ambulacral areas are of unequal width; the posterior pair are nearly one
fourth wider than the anterior pair, and the single area is the widest (fig. 1 z). The anal valley
extends from the posterior part of the disc to the border; it is narrow above, wider in the
middle, and expanded below, in the excavated portion; it has vertical parallel walls, which
oradually diverge, then approximate, and afterwards expand outwards, forming a well-
defined groove (fig. 1 a). The pyriform anal opening is situated at the extreme end of the

* ©Annals of Natural History,’ 2d series, vol. ii, p. 416.

44

336 ECHINOBRISSUS

valley (fig. 1 d). The surface of all the plates is covered with small, close-set, spinigerous
tubercles, surrounded by circular areolas, and having the interspaces minutely granulated
(fig. 1 e). At the base the tubercles are larger, their summits are perforated, and they
are surrounded by wider and deeper areolas (fig. 1 4). The diagram of the dorsal structure
(fig. 1 2) shows the relative disposition of the plates in both the areas and poriferous zones,
and fig. 1 & is a correct figure of the Rev. A. W. Griesbach’s unique and largest
specimen from the Cornbrash of Rushden.

The apical disc (fig. 1 g) is composed of four perforated ovarial plates, and a small
imperforate ovarial. The right antero-lateral plate is the largest, and extends into the
centre of the disc; it supports on its surface a prominent spongy madreporiform body.
The left antero-lateral and postero-lateral ovarials are about the same size; the oviductal
holes in each are near the apex of the plates; the single imperforate plate is much smaller
than the others. The five ocular plates, with marginal eye-holes, are wedged in the angles —
of the ovarials, and the surface of all the discal plates is granulated. Fig. 1 g represents
these discal elements in the most perfect development I have ever met with them in this
species, and it is, I believe, the first correct figure which has been given of the apical disc
of this common and well-known urchin.

The base is more or less concave, most so in the pyramidal varieties (fig. 1 4); the
ambulacral areas radiate in depressed furrows from the margin of the mouth-opening,
becoming shallower and wider as they approach the border. The poriferous zones are
more apparent near the peristome, and the pores lie close together in oblique pairs. The
mouth-opening is excentrical, being situated in a deep depression nearer the anterior than
the posterior border. The tubercles at the base are larger and set wider apart than those
on the dorsal surface; their summits are likewise perforated, and their bosses surrounded
by wider and deeper areolas (fig. | 2), the intermediate space being filled with larger
granules.

Affinities and differences.—This species resembles very much . scutatus, Lamk., and
Fi. dimidiatus, Phil.; it is distinguished from these forms by the length of the anal
valley, which extends from the disc to the margin, whilst in Z. scutatus, Lamk., and
EL. dimidiatus, Phil., there is an undepressed portion of test between the disc and the
commencenent of the valley. The posterior lobes are likewise more tapering and less
tumid than in the Coral Rag species. . clunicularcs is distinguished from #. ordicularis,
Phil., by its sub-quadrate shape, by its sides increasing in diameter towards the posterior
part, and by its posterior bilobed border. ‘The same group of characters serve to dis-
tinguish it from &. Woodwardii, Wright, a species remarkable for its tumid sides and long
narrow anal valley.

Locality and Stratigraphical position —This urchin makes its first appearance in the
. Clypeus Plottii bed of the Inferior Oolite, in the zone of Ammonites Parkinsoni. The

FROM THE GREAT OOLITE. 337

specimens from this rock often attain a considerable size ; the flattened varieties are the
largest, and the pyramidal the smallest. I have collected this species from the upper zone
of the Inferior Oolite at Rodborough, Birdhp, and Shurdington Hills, and from Hampen,
Naunton, and Stow-in-the-Wold, Gloucestershire; from the Stonesfield Slate at Seven-
hampton, Eyeford, and near Pewsdown; from the Great Oolite of Minchinhampton,
Salperton, and near Cirencester; from the Forest Marble near Trowbridge; from the
Cornbrash near Cirencester, Gloucestershire; and from Chippenham and Trowbridge,
Wilts. Mr. Hull has collected it from that formation near Shilton, and Mr. Gavey near
Woodstock. ‘The Rev. A. W. Griesbach has collected the finest specimens I have seen
from the Cornbrash at Rushden, Northamptonshire, where they attain a very large size
(fig. 1 a, *), and are found im excellent preservation. Messrs. Bristow and Gapper, of the
Geological Survey, collected specimens in abundance from the Cornbrash of Dorset, and I
have likewise found it in the same rock at Gristhorpe Bay, and Scarborough, Yorkshire.
It forms, therefore, a very characteristic urchin of the upper portion of the lower division
of the Oolitic series, extendmg without interruption from the zone of Ammonites
Parkinsoni to the uppermost beds of the Cornbrash; a practised eye, however, can
readily detect the varieties which are gathered from the Inferior Oolite, Great Oolite,
and Cornbrash; the Inferior Oolite forms are usually large and depressed, the Great
Oolite small and dwarfed, and the Cornbrash the largest and best developed of the series.

The foreign distribution of this species, according to M. Desor, is Calcaire 4 Polypiers
(Bathonien) de Ranville, Forest-Marble de Chatel-Censoir (Yonne), Vesulien du Hornussen,
Kreisacker, Wolfliswyl et Frick (Argovie), Meltingen. (Canton de Soleure), Maiche
(Doubs).

It was collected in abundance by M. Triger from the Great Oolite (department of the
Sarthe) at “La Jauneliére (tuilerie), Domfront (four a chaux), Conlie, Monné, Saint-
Christophe, route de Mamers a Maroiette, Aubigné (ferme de Gesnes-le-Gaudelin),
Pécheseul, Noyen, Saint-Pierre-des-Bois, route de Contilly a la Perriere.”

Table of M. Triger, Bradford Clay, Ass. Nos. 1, 2, and 3, and Forest Marble, Ass. No. 4.

B. Species from the Great Oolite.

Ecurnosrissus Woopwarpit, Wright. Pl. XXIV, fig. 2 a, 4, ¢, d, e.

NucLEeoLires WoopwaRrDil. Wright, Annals and Magazine of Natural History, 2d series,
vol. 13, p. 161, pl. xii, fig. 5 a—e, 1852.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed.,
p. vill, ad. sp.
Ecuinoprtissus Woopwarpu. Desor, Synopsis des Echinides Fossiles, p. 268.

Test thin, sub-quadrate ; sides tumid ; dorsal surface flatly convex; anal valley deep,

338 | ECHINOBRISSUS

narrow, and spear-shaped, extending from the apical disc to the posterior border;
ambulacral areas narrowly lanceolate ; posterior lobes short, and truncated; base flat ;
inter-ambulacral areas slightly inflated at the base; single inter-ambulacrum scarcely
produced ; mouth-opening pentagonal, excentral ; apical disc small, central.

Dimensions.—Height, six tenths of an inch; antero-posterior diameter, one inch and
one tenth ; transverse diameter, one inch and one fifth ; the larger specimens are so much
deformed that their proportional dimensions cannot be accurately given.

Description.—This species was formerly considered a variety of &. orbicularis, Phil.,
but a careful study of many specimens of the former, compared with good typical examples
of the latter, convinces me that these two urchins are specifically distinct.

The test is thin, and not often well preserved ; the specimen drawn (fig. 2 a, 6) isa small
but tolerably perfect individual ; the outline is sub-quadrate, the shell is one tenth of an inch
more in breadth than in length; it is a little narrower anteriorly, than posteriorly, and
the posterior border is broadly truncated ; the sides are very tumid (fig. 2 c), sometimes
irregularly so; and the test is higher across the apices of the postero-lateral ambulacra
than at any other point (fig. 2c); the tumidity of the sides produces a greater flatness of the
upper surface than is observed in any of its congeners. ‘The ambulacral areas are
nearly all of the same width; they have a narrow, graceful, lanceolate form (fig. 2 a),
from the mouth to about midway between the margin and the apical disc they are
nearly all of equal width; at this point the pores gradually change their form, they are
slightly separated for a short distance, and again converge as they approach the disc;
the pores of the inner row are round (fig. 2 d), those of the outer row form oblique slits ;
the widest part of which is external; the round pores are formed by notches in the upper part
and sides of the small plates forming the avenues, and the oblique pores by uncalcified
portions of the margins of the same plates; from the termination of the petaloidal
portion of the zones to the mouth, the pairs of pores are small, and set wider apart,
whilst the diameter of the areas remains the same; near the peristome they are crowded
close together and form arches, the convexity of which is towards the mouth-opening.
The inter-ambulacral areas are of unequal width ; the anterior pair are the narrowest, the
posterior are wider than the anterior pair, and the posterior single inter-ambulacrum is the
widest (fig. 2 a). The anal valley forms a long narrow depression,extending from the disc to
the border ; it has perpendicular sides, and a small vent opens into it about the middle;
the base is flat, becoming more or less concave near the mouth (fig. 2 6); the anterior and
posterior pairs of mter-ambulacra are moderately convex in this region, and the basal
portion of the inter-ambulacrum is very slightly produced ; the mouth-opening is excentral,
situated in a depression nearer the anterior than the posterior border; the peristome has a
pentagonal shape, with five rudimentary lobes. The surface of the plates is covered with
microscopic tubercles (fig. 2 @), arranged in tolerably regular oblique rows ; on each plate

FROM THE GREAT OOLITE. 339

there are from twenty to thirty, disposed in three or four rows (fig. 2 d); and those
at the base are somewhat larger than the tubercles on the upper surface. ‘The apical disc is
small, and nearly central ; its elements are so intimately soldered together, that its general
form alone can be made out ; none of the specimens I have examined display the separate
plates ; the eyeholes are marginal, at the apices of the ambulacra, and the ovarial holes
are further outwards, and between them, whilst the madreporiform tubercle occupies the
centre of the disc. The test is very thin, and almost always deformed by tumidity, and
the upper surface is often irregular from this cause. The beauty and regularity of the
small specimen I have figured, forms an exception to almost all the other specimens
T have seen.

Affinities and differences.—This species resembles most Z. orbicularis, Phil., which is the
only form amongst its Oolitic congeners for which it can be mistaken. The following diag-
nostic characters will enable the geologist to distinguish these allied forms from each other.
In #. Woodwardit the sides are very tumid, and the dorsal surface is flat, whilst in 2. orbicu-
laris the sides taper, and the upper surface is convex. In 2. Woodwardii the base is flat, and
the inter-ambulacra are slightly produced, whilst in &. ordicularis the base is concave, and
the inter-ambulacra convex and prominent. In &£. Woodwardii the anal valley is
narrow, in Z. orbicularis it is wide. In #. Woodwardii the outline is sub-quadrate, in
E. orbicularis it is circular; the petaloidal disposition of the dorsal portion of the
poriferous zones extends farther down the sides in /. orbicularis than in L. Woodwardir.
It differs from #. Brodiec and #. scutatus in the anal valley extending from the disc
to the border, whereas in these species there is always an undepressed portion of test
between the disc and the valley. Between 2. Woodward and L. clunicularis the dif-
ference in the general shape and development of the posterior lobes is so great, that they
cannot be mistaken for each other.

Locality and Stratigraphical position.—I have collected this urchin from the Great
Oolite at Minchinhampton, near Cirencester, at Salperton tunnel, Great Western Railway,
at Highgate, and near Pewsdown, Gloucestershire, and at Burford, Oxon; as far as I
know, it has not been found out of the Great Oolite. Mr. John Bravender, of Ciren-
cester, collected this species at Tetbury, and between Tetbury and Bourton-on-the- Water,
embracing a distance of twenty-five miles, in ten or twelve different localities; the
specimens were found in a hard marly rock, at the upper part of the Great Oolite ; the test
is unfortunately not often well preserved. Mr. Frederick Bravender has kindly sent me
the following note on the distribution of this urchin, which I herewith give entire :

“ Echinobrissus Woodwardit is generally found in a rubbly bed, nearly, if not quite, at
the top of the Great Oolite ; and although this stratum covers a considerable tract of elevated
country in the neighbourhood of Cirencester, this urchin has not been collected very
plentifully, except in one or two localities. It has been found at Perrimore Quarry, on

340 ECHINOBRISSUS

the Royal Agricultural College Farm, which is the best locality ; at Coates, at the Wood-
house in Earl Bathurst’s Park, at Downs Farm, and Stowell Park, on the Stow Road,
and at Stratton, and North Cerney, near Cirencester. ‘The specimens obtained from the
Woodhouse were from some light excavations to mend a private road, where they were
abundant. In one instance (near Stowell Park) the rubbly bed containing the Z.
Woodwardii was covered over with Bradford Clay, about two feet in thickness, when
the characteristic fossil Zerebratula digona, Sow., occurred in abundance. In two or
three instances . Woodward was found associated with Zrigonia Phillipsii, Lyc., which
has not been very long recognised as a Gloucestershire shell; it is not improbable that
the two may be found together in Northamptonshire. I am not aware that this species has
been found out of the Great Oolite.

In three specimens collected from the same white marly bed of the Great Oolite, whilst
this sheet was passing through the press, the small apical disc is better preserved than in
those I had previously examined. The ovarial plates are long, narrow, and lanceolate,
with large, oblique, oviductal holes, perforated near their apices, the madreporiform body
covers so much of the disc, that I cannot discern whether there are supplementary plates
im its centre as in L. orbicularis. The ocular plates are small, and have minute marginal
orbits.

Ecuinosrissus GrizsBacuil, Wright, nov. sp. Pl. XXV, fig. 1 a, 4, ¢, d, e, f.

Test quadrate, elevated ; sides tumid ; posterior lobes small ; apical disc large, expanded ;
anal opening large, adjoiming the disc without any intermediate depressed space between
the disc and the vent; poriferous zones narrow; pores approximated throughout ; anal
valley wide.

Dimensions.—Height, four tenths of an inch; antero-posterior diameter, three
quarters of an inch; transverse diameter, nearly equal to the length.

Description.—I am indebted to my friend, the Rev. A. W. Griesbach, for calling my
attention to this new form, which has hitherto, doubtless, been considered a small variety
of #. clunicularis. After a careful study of this urchin, I feel disposed to adopt my
friend’s view, and in justice to Mr. Griesbach, I subjoin his notes on this species, in which
he has most accurately pointed out its diagnostic characters :

“There is a small nucleolite found in the Great Oolite round about here, which I have
for a long time heedlessly confounded with JV. clunicularis, but which I yesterday discovered
to be quite a distinct form, and I do not know any other species to which it can be
referred. I have seen it at Wimmington, Higham Ferrers, and Blisworth, and have
received a specimen from Mr. Brodie from ‘ Fuller’s Earth Rock, Gloucestershire.’ The

FROM THE CORNBRASH. 341

specimens I have seen and collected have been, with only one exception, either entirely
denuded of the test, or else so eroded as to leave no structure visible. I send you the one
exception, which I found at Blisworth about four years ago (fig. 1 a, c). It is narrower than the
usual form, which is quadrate—as broad as it is long. Mr. Brodie’s specimen is con-
siderably larger, but, though having the test, it has been scraped and spoiled. Compared
with JV. clunicularis (of which I have seven beautiful specimens from the Cornbrash of
Rushden before me, four of these are depressed, and three high and conical), this nucle-
olite, among minor differences, presents the following main distinctions :

Affinities and differences.—‘ \st. Whereas in L. clunicularis there is always a narrow
depressed space (as long as the anal opening itself) between the apical disc and the vent ;
in 2. Griesbachii there is no such space, but the anal aperture zmmediately adjoins the
apical disc (fig. 1 a, ¢).

“2d. The apical disc is proportionally much larger than in #7. clunicularis, in con-
sequence of which the apices of the ambulacra do not approach each other so nearly, and
the perforations in the disc are wider apart (fig. 1 0).

“Tn this small urchin (fig. 1 @) the disc is fully as broad as in a fine specimen of £.
clunicularis—one inch and three tenths in antero-posterior diameter.

“Tf several false species have been made out of &. clunicularis, that is no reason
why we should too readily unite different forms under that name. I think this i
a distinct species, and hope, therefore, to have avoided what might otherwise have been
said, ‘Incidit in Scyllam cupiens vitare Charybdim.’ I have no idea that this form
is rare in the Great Oolite, but it appears to have been overlooked.”

EcHINOBRISSUS ORBICULARIS, Phillips. Pl. XXV, fig. 2 a, 6, ¢,d,¢,f, 9.

CLYPEUS ORBICULARIS. Phillips, Geology of Yorkshire, tab. vii, fig. 3, 1829.
a = Agassiz, Prodrome d’une Monogr. des Radiaires Mem. Soc.
des Sc. Nat. de Neuchatel, t. i, p. 136, 1836.
— — Dujardin, in Lamarck, Animaux sans vertébres, 2d ed.,
t. iii, p. 348, 1840.
= = Morris, Catalogue of British Fossils, p. 50, 1843.
NUCLEOLITES ORBICULARIS. Forbes, Memoirs of the Geological Survey, decade first,
description of pl. vii, 1849.
— — Wright, Annals and Magazine of Natural History, 2d series,
vol. ix, p. 301, 1851.
—_ — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 84,
1854.
Davoust, Note sur les Foss. Spéciaux, a la Sarthe, p. 25,
1856.
EcHINOBRISSUS ORBICULARIS. Desor, Synopsis des Echinides Fossiles, p. 265, 1857.
_ — Cotteau and Triger, Kchinides du departement de la Sarthe,
— _— pl. ix, figs. 5—8, p. 57, 1858.

342 ECHINOBRISSUS

Test orbicular ; upper surface irregularly convex and depressed; sides tumid; apical
disc complex and central; ambulacral areas lanceolate ; poriferous zones narrowly petaloid
between the border and disc ; posterior lobes obsolete ; anal valley broad, extending from
the disc to the border ; vent large, situated in the upper part, near the disc; base flat or
slightly concave ; mouth sub-central, situated in a depression nearer the anterior border.

Dimensions.—Height, eight tenths of an ich; transverse diameter, one inch and six
tenths; antero-posterior diameter, one inch and six tenths.

Description.—The tumid sides, obsolete lobes, orbicular circumference, its length and
breadth being equal, with the broad, flat, and somewhat irregular dorsal surface, serve to
distinguish this species from its congeners.

The ambulacral areas are narrow, and nearly all of the same width (fig. 2 a); they have
a more petaloidal form than in the preceding species, and are furnished with two rows of
small tubercles arranged in zig-zag lines on the areas, the external row being the largest
and most regular (fig. 2 e), whilst the middle of the area is covered only with minute
granules.

The poriferous zones are moderately wide, and with the ambulacral areas form well-
developed petaloidal figures on the upper surface of the test ; the pores of the inner row
are round, those of the external row are oblong (fig. 2 e); there are about six pairs of
holes opposite each inter-ambulacral plate; on the upper surface the pores are wider
apart (fig. 2 g), on the sides they are close together (fig. 2 c), at the margin they are very
indistinct (fig. 2f), at the base they are scarcely visible and still more widely apart, and
continue so to the peristome (fig. 2 4).

The imter-ambulacral areas are of unequal width; the antero-lateral pair are the
narrowest, the postero-lateral are wider, and the single area is the widest (fig. 2 a, 3);
the sides are more or less tumid (fig. 2 c), and the upper surface is irregularly convex (fig. 27),
in consequence of the antero- and postero-lateral areas being slightly depressed in the
centre (fig. 2 c, f); the inter-ambulacral plates form long pentagons, bent upwards in the
middle (fig. 2 e). Each plate is covered with about twenty very small tubercles, arranged
in three rows ; in a large majority of specimens they are so minute on the sides, margin,
and upper surface that it requires the aid of a good lens to discover them, at the base they
are larger and crowded closer together; each tubercle is surrounded by a sunken areola
(fig. 2 e), and the inter-tubercular surface of the plates is closely crowded with microscopic
granules which encircle the areolas or fill up all the intervening spaces. The single inter-
ambulacrum is not at all produced, and the lobes are very small. The anal valley is large ;
it commences at the posterior border of the disc and extends to the margin (fig. 2 a. g).
The large vent has an elliptical shape, and opens near the surface in the upper third of the
valley, whilst the lower two thirds of that depression form a considerable furrow in the
middle of the area (fig. 2 a, 9).

FROM THE CORNBRASH. 343

The apical disc is large, and presents a very remarkable modification of the usual type
of structure observed in other Ecuinoprissipm. As I have seen this structure in
many specimens collected from localities widely apart, it must be regarded as a normal
form in this species. Mr. Bone has figured this curious disc with great accuracy at
fig. 2 d; the two pair of perforated ovarial plates have a pyriform shape, the right antero-
lateral is the largest, and supports the spongy madreporiform body; between these there
are introduced into the middle of the disc four small plates, and posterior to them three
other smaller plates. The front rows are bounded before by the madreporiform plate,
and behind by the left posterior ocular plates, and the three posterior plates lie between
the posterior oculars. The surface of all the elements of the disc is covered with
numerous close-set tubercles. The five ocular plates are cordate in form, and have mar-
ginal orbits. The abnormal deviation from the usual structure consists in the introduction
of two rows of small plates behind and between the normal discal elements.

The base is concave and undulated (fig. 2 4), from the prominence of the inter-
ambulacra (fig. 2f) and the depressions formed by the ambulacra which radiate in straight
furrows from the peristome to the margin. The mouth lies at the bottom of a subcentral
depression. ‘The peristome is central and slightly five-lobed; the tubercles are more con-
spicuous at the base than on the upper surface, and are closely placed upon the plates.

The test is very thin, and the spines, which were preserved on one specimen, are °
moderately long and needle-shaped.

Affinities and differences.—The orbicular form and long anal valley liken this species
to Echinobrissus Woodwardii, Wr., but the convexity of the upper surface, the wideness
of the anal valley, the concavity of the base, and the slight tumidity of the sides, form a
group of characters of sufficient value to distinguish it from that congeneric species. It
resembles some of the small round varieties of Hchinobrissus Hugii, Ag., but is readily
distinguished from them by the anal valley extending from the disc to the border, whereas
in Lchinobrissus Hugii, Ag., there is always an undepressed portion of test between
the disc and upper limit of the anal valley. From all other Oolitic species it is so
entirely distinct that it is not likely to be mistaken for either of them.

Locality and Stratigraphical position.—This is a true Cornbrash urchin. I have
collected it from that “terrain” near Cirencester, and Miss Slatter found it in the same
rock near Fairford. Professor Phillips obtained his original type specimens from the
Cornbrash at Scarborough, and I have collected it out of the same bed. I am indebted to
my friend, John Leckenby, Esq., for a good series from that locality; and Edward Wood, Esq.,
of Richmond, most liberally gave me the fine large specimen from Scarborough figured in
Pl. XXV, fig. 2 a. I have received a very fine series of this species from my friend, the
Rev. W. A. Griesbach, which he collected from the Cornbrash at Rushden, Northampton-

shire; these specimens have supplied abundant materials for the curious structure of the
A5

344 ECHINOBRISSUS

disc and other interesting details. One of these urchins (fig. 2 f, g) enabled me to exhibit
a conoidal variety which sometimes occurs, but it would require many figures to do full
justice to all the variations of outline observed in the Northamptonshire specimens ;
which likewise exhibit the sculpture on the plates much better than those from Yorkshire.
The Gloucestershire specimens are rarely well preserved. This species is exceedingly rare
in the Wiltshire Cornbrash, which contains in such abundance #. clunicularis, Lhwyd.

M. Triger collected &. orbicularis from the Forest Marble, Ass. No. 4, department of
the Sarthe, at Pécheseul, Noyen, route de Mamers a Montagne, where it is very rare.
I know of no other foreign locality in which it has been found.

HcHINOBRIssUS QuADRATUS, Wright, nov. sp. Pl. XXVI, fig. 1a, 4, ¢, d.

Test quadrate, elongated, depressed, narrow before, wide behind; posterior border
deeply sulcated ; anal valley short, wide, and with sloping sides, extending to the apical disc,
which is excentral and nearer the posterior border; dorsal surface much inclined from the
apical disc to the anterior border; sides narrow; base very concave; plates of the test
closely covered with small tubercles.

Dimensions.—Height, seven tenths of an inch ; antero-posterior diameter, one inch and
nine twentieths ; transverse diameter, one inch and three tenths of an inch.

Description.—This nucleolite has by some been considered to represent /Vucleolites
major, Agass., in the English Oolitic rocks, but a careful examination of M. Agassiz’s
figure, given in the ‘Hchinodermes Fossiles de la Suisse,’ will convince the inquirer that
this urchin is very distinct from the Swiss form; im our nucleolite the apical disc is
excentral, and situated nearer the posterior border, whereas in #. major the excentral disc
is nearer the anterior border ; the mouth-opening in our nucleolite is small and nearly
circular, whilst in #. major it is pentagonal, and much nearer the anterior border. Besides
these organic distinctions, they belong to widely different stages of the Oolitic rocks, Z.
quadratus, Wright, beg found in the Cornbrash, whereas 1. major, Agas., was collected
from the “terrain Portlandien de la Vallée de la Birse.”

L. quadratus is a large, elongated nucleolite, with a well-defined quadrate outline, much
wider behind than before ; the upper surface is flat, and the slope from the disc to the anterior
border is long and gently declined ; the ambulacral areas are nearly all of the same width, and
terminate at a short distance from the apical disc, (fig. 1 a); they pass entirely straight
from the border to the disc, without forming curves as in Z. clunicularis, Lhwyd.

The poriferous zones are narrow; the pores forming the external row are only a
little larger than those of the inner row (fig. 1 d), and there are seven pairs of pores opposite
each large plate ; the inter-ambulacral areas are of unequal width, the anterior pair are

FROM THE CORNBRASH. 345

the narrowest, and the posterior pair and single inter-ambulacrum are the same diameter ;
their upper surface is uniformly convex, and the plates are covered with tubercles,
set closely together (fig. 1 d). There are five or six rows on each plate, the areolas of
which are so nearly approximated that there are much fewer granules between them than
in the nearly allied 7. clunicularis ; the tubercles likewise are larger than in that species.
(Compare Pl. XXIV, 1 e, with Pl. XXXVI, fig. 1 @.)

The upper surface of the single inter-ambulacrum is very much depressed to form the
anal valley, the sides of which slope obliquely inwards, and form an angle of 65° with the
base (fig. 1 a); the posterior border is much indented by this depression, and forms quite
a concave depression behind (fig. 1 a, 6).

The apical disc is rather larger than in FZ. clunicularis ; it occupies the vertex of the
test, and is placed nearer the posterior than the anterior border. The four genital
holes are large and distinct, and the madreporiform body is not very prominent.

The base is concave, and the small excentral mouth-opening (fig. 1 4) is situated
nearer the anterior than the posterior border; the peristome is circular or subpentagonal,
with five rudimentary oval lobes. The poriferous zones lie in depressions, and
distinctly radiate from its circumference (fig. 1 4). The basal tubercles are larger than
the dorsal; they are placed so close together that the areolas are separated only by single
rows of granules (fig. 1 4).

Affinities and differences.—I have already pointed out the diagnostic characters by
which this species is distinguished from #. major, Agas., the nucleolite which most nearly
resembles it in form, size, and general outline. Its next nearest affinity is with 2. clunicu-
laris, Lhwyd; from this species it is distinguished, however, by its quadrate shape and
depressed dorsal surface, by the wide anal valley, with its oblique sloping sides and concave
posterior border. The apical disc is likewise situated behind the centre of the test,
and the tubercles are larger and more closely crowded together. The structure of the
anal valley and the excavated character of the single inter-ambulacrum serve at a glance to
distinguish it from Z. scutatus, Lamk.

Locality and Stratigraphical position.—All the specimens that I know of this species
were collected by Mr. William Buy from the Cornbrash near Sutton-Benger, Wilts,
where it is extremely rare; it occurs with the small gray variety of L. clunicularis,
associated with Holectypus depressus, Lamk., Acrosalenia Wiltom, Wright, Acrosalenia
hemicidaroides, Wright, Stomechinus intermedius, Agas., Acrosalenia spinosa, Agas.,
Avicula echinata, Sow., Terebratula obovata, Sow., Terebratula lagenalis, Schloth., and other
well-known Cornbrash forms.

346 ECHINOBRISSUS

C.—Species from the Coralline Oolite.

Ecuinoprissus scutatus, Lamarck. Pl. XXXVI, fig. 2, 6, c,d, e, f.

ECHINITES CORDATUS. Lang, Lapid. Figur. Helvetize, p. 119, tab. xxxv, fig. 1, 1708.

ECHINOBRISSUS ELATIOR. Breynius, Schediasma de Echinis, p. 63, tab. vi, fig. 3, 1732.

SPATANGUS DEPRESSUS. Leske, Additamenta ad Kleinii Dispositionem Echinodermatum,

p- 238, tab. li, figs. 1, 2, 1778.

NUCLEOLITES SCUTATUS. Lamarck, Syst. Animaux sans vertébres, tome iii, p. 36, 1816.

CLYPEUS CORDATUS. Smith, Strata Identified, plate of Coral Rag Fossils, 1817.

EcHINUS DEPRESSUS. Schlotheim, Petrefactenkunde, p. 313, 1822.

NUCLEOLITES SCUTATUS. Defrance, Dict. des Sciences Naturelles, tome xxxv, p.213, 1825.
—_ SCUTATA. Blainville, Dict. des Sciences Naturelles, tome xxxv, p. 213, 1825.
— SCUTATUS. Deslongchamps, Encycloped. Method., ii, p. 570, No. 1.

— — Goldfuss, Petrefacta Germaniz, Band. i, tab. xliu, fig, 6 a—e,
p. 140, 1826.

-- —_— Desmoulins, Tableaux Synop. Echinides, p. 356, No. 5, 1836.

— — Agassiz, ‘Echinodermes Foss. de la Suisse, p. 45, tab. vii,
figs. 12—21, 1839.

— CLUNICULARIS, var. a major. Forbes, Memoirs of the Geological Survey,
decade Ist, pl. 1x, 1849.

_ SCUTATUS. D’Orbigny, Prodrome de Paléontologie, tome i, p. 379, 1850.

— — Bronn, Lethza Geognostica, 3d Aufl. zweit, Band., p. 151,
tab. xvii, fig. 13, 1851.

_— — Wright, Annals and Magazine of Nat. Hist., 2d series, vol. 13,
p. 185, 1851.

_ DIMIDIaTUS (pars) Wright, Annals and Magazine of Nat. Hist., 2d series,
vol. ix, p. 301, 1851.

— SCUTATUS. Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 84,
1854.

EcHINOBRIssus scuTaTus. Desor, Synopsis des Hchinides Foss., p- 277.

Test elliptical, sub-quadrate, rounded before, enlarged, expanded, and bilobed behind ;
upper surface convex, more or less depressed; sides tumid; base concave; apical
disc small, excentral, nearer the anterior border; dorsal valley wide, with perpendicular
walls; apex separated from the disc by an undepressed portion of test ; valley extending
about two thirds the distance between the vertex and border; vent large and
elliptical ; base concave, much depressed at the excentral mouth-opening ; peristome
slightly pentagonal.

Dimensions.—Height, seven tenths of an inch; antero-posterior diameter, one inch
and three tenths ; transverse diameter, one inch and a quarter.

Description.—It is impossible to decide whether the urchin figured by Plot* in tab.

* «History of Oxfordshire.’

FROM THE CORALLINE OOLITE. 347

ui, fig. 12, and by Lister* (tab. 7, fig. 26), refers to this species or &. clunicularis, in
consequence of the omission of the anal valley in these figures, on which the true specific
character strictly depends. Down toa very recent date, the two forms have been confounded
with each other, although, when critically examined, the differences are very evident. The
stratigraphical distribution of the two species is moreover well defined, 7. clunicularis
ranging from the superior zone of the Inferior Oolite to the Cornbrash, whilst 2. scutatus
is limited to the Calcareous Grit and other subdivisions of the Coral Rag. The abundance
of this nucleolite in the Calcareous Grit near Oxford makes it highly probable that this was
the form the older authors above cited had in view in their respective works. Lang’st
“ Echinites Cordatus quaternis radiis é duplici serie transversarum lineorarum conflatis”
(tab. 35, fig. 1), probably represents a bad specimen of this urchin, in which the single
ambulacrum had been obliterated. The specimen is described as being very rare, and
was found in the hills around Betstein and Luggeren. Leske’s{ figure of Spatangus
depressus (tab. 51, fig. 1) apparently represents a quadrate depressed variety of this
species, but in consequence of the anal valley being filled up with matrix, the true
specific character is concealed. Many authors are of opinion that the figure of Goldfuss§
does not represent the true Lamarckian Seutatus, and Desmoulins has proposed to separate
it, under the name Goldfussit; but after having studied a large number of individuals
collected at ‘I'rouville, I have found many specimens with which the figure of Goldfuss
entirely agrees. A sufficient margin has not been allowed for the varieties which the same
species exhibits when obtained from different localities. M. Agassiz’s || figure of this
nucleolite is very good, and represents, I think, the true type form of the species. This
author participates in the opinion expressed by Desmoulins, in reference to which he says—

“En revanche je pense avec M. Desmoulins que Goldfuss a identifié 4 tort ’'espéce qu'il
a décrite sous le nom de JV. seutatus, avec le JV. scutatus de Lamarck, dont nous nous
occupons en ce moment. Ce dernier en effet n’affecte nullement cette dépression de la
face supérieure postérieure qui est trés saillante dans les figures de Goldfuss; c’est au
contrare 4 la face antérieure qui est la plus inclinée.” ‘‘ Afin de destinguer Je JV. scutatus,
Lam., du JV. sewtatus, Goldf. (qui n’a point encore éte trouvé en Suisse), M. Desmoulins a
donné a ce dernier le nom de WV. Goldfussit.”’F

Professor Edward Forbes** considered this species as a variety of JV. clunicularis, and
described it as ‘Var. a major, sub-depressa, lata, lateribus, tumidiusculis. Spatangus
depressus, Leske, ap. Klein, p. 238, t. 51, fig. 12 (copied in ‘Enc. Meth., pl. 157, figs.

* ©De Lapidibus Turbinates,’ cap. ii, titulus xxvi.
+ ‘Historia Lapidum Figuratorum Helvetiz,’ tab. 35, p. 119.
t ‘Additamenta ad Kleinii Echinodermata,’ p. 238, tab. 51, figs. 1, 2.
§ ‘Petrefacta Germaniz,’ tab. 43, fig. 6.
|| ‘Echinodermes Fossiles de la Suisse,’ tab. vii, figs. 19—21.
q Ibid., partie premiere, p. 46.
** «Memoirs of the Geological Survey, decade 1, pl. ix.

348 ECHINOBRISSUS

5, 6). Vucleolites scutata, Lamarck, ‘ An. s. Vert.,’ 1, p. 35; Defrance, ‘ Dict. Sc. Nat.,’
vol. xxxv, p. 213. WV. scutatus, Agassiz, ‘ Echin. Suiss.,’ p. 45, pl. 7, figs. 19—21.” This
quotation shows my lamented friend’s opinion when the description of his Pl. IX was
written. At that time I believe he had not seen my Trouville specimens of F. scutatus,
for on making with him a comparison of some type-forms of WV. scutatus, Lamk., he readily
admitted, after that examination, the specific differences existing between the NV. clunicularis
and the true Lamarckian species.

In my first memoir on the Cassidulidze of the Oolites,* I grouped several individuals of
this species with H. dimidiatus, Phil. At that time nearly all the English Coral Rag
nucleolites were referred to Phillips’s species ; and I was only convinced of my error after
I had examined a series of good type-specimens from ‘Trouville, the original locality
of Lamarck’s species.

Lehinobrissus scutatus, Lamk., when fully developed, is uniformly convex on the upper
surface; it is rather narrower before than behind; its length nearly equals its breadth,
when measured about the middle of the test; the flanks are rounded and tumid (fig. 2 0),
and the posterior border is truncated (fig. 2 4); the vertex is situated nearer the anterior
than the posterior border, and in the centre thereof is placed the apical disc ; from this
point the test slopes gently towards the posterior border, but more abruptly to the anterior
side (fig. 2 c); the ambulacral areas are narrow, and nearly uniform in width, the
posterior pair being a little broader than the anterior areas. The poriferous zones are
petaloidal only on two thirds of the upper surface (fig. 2 a, c). The pores of the imner
row are round, those of the outer row form oblique slits; on the flanks they are both round,
more distant, and placed obliquely, thus -.’..°.:; at the border they become very small,
and at the base indistinct; near the peristome they are again larger and more
numerous ; in the more crowded portions of the zones there are from six to seven pairs of
pores opposite one of the large plates, and where they are more distinct on the sides there
are four small pairs opposite one plate.

The two anterior mter-ambulacral areas are narrower than the posterior pair (fig. 2 a).
There are about sixteen plates in a column, each plate forming a double inclined plane,
and having its surface crowded with small equal-sized tubercles, arranged close together
in three or four rows (fig. 2,7); the postero-lateral pair are wider and longer, and contain
more plates in each column; in other respects they have a similar structure to the anterior
areas. The single inter-ambulacrum is about as wide as the postero-lateral pair ; it is
truncated behind, and its border is grooved by the anal valley; this depression has a
uniform width, is concave at its base and upper part, and there is always an undepressed
portion of test between its termination and the apical disc (fig. 2 a); the anal opening
is round, and is seen at the end of the valley (fig. 2 a, d).

The apical disc is small and excentral ; its elements are so intimately soldered together,
that the sutures in all my specimens are obliterated ; the madriporiform tubercle is large

* © Annals and Magazine of Natural History,’ 2d series, vol. ix, p. 300.

FROM THE CORALLINE OOLITE. 349

and occupies the centre of the disc ; it appears to cover the genital plates (fig. 2 e), and
the four genital holes are large oblique slits, which extend into the inter-ambulacral areas
(fig. 2 e).

The base is nearly flat at the sides, and slightly concave towards the mouth-opening
(fig. 2 4). In large, well-developed specimens, the inter-ambulacral areas are a little
prominent, and the course of the ambulacra is marked by corresponding depressions in
the test; the poriferous zones are so feebly shown, that the pores can only be seen with a
lens.

The mouth-opening is moderately large for a nucleolite; it is situated in a depression
opposite the apical disc, and is nearer the anterior than the posterior border (fig. 2 4) ;
the peristome is pentagonal, and each angle of the pentagon corresponds to an ambulacral
area; the areas form inconsiderable petaloidal expansions as they radiate from the peristome,
and the pores are crowded close together in the vicimity of the mouth-opening. The anal
valley forms one of the distinctive characters of this species (fig. 2 a); it is of an ovate or
lanceolate form, with a blunt apex; in some specimens it appears as if a portion
of the imter-ambulacrum had been drilled out for the passage of the intestine; in
some individuals it extends only half the distance between the margin and the vertex, whilst
in others it reaches two thirds the length; in all the specimens I have examined, an
undepressed portion of test separates the apical disc from the upper border of the anal
valley ; inferiorly, the valley forms a considerable sulcus, grooves the centre of the area,
dividing its posterior border, and producing the cordate or bilobed form this species
assumes (fig. 2 a, 4).

Affinities and differences.—I have already stated that #. scutatus was formerly
considered by English naturalists to be a variety of H. clunicularis, Lhwyd, and as such its
history is more or less connected with that species. Were astudent, therefore, to endeavour
to unravel its synonyms from the books alone, he certainly would be puzzled in his search,
as the critical remarks on £. scutatus have more frequently been made on book-statements
than from an examination of specimens. If, however, a comparison be made between a
series of 2. clunicularis, Lhwyd, from the Cornbrash, with a corresponding series of £.
scutatus, Lamk., from the Calcareous Grit, all doubts will be removed from the mind of the
observer as to the specific differences existing between these species; and in default of such
specimens, a careful study of Mr. Bone’s most excellent figures in our Plates XXIV and
XXVI, with the ample magnified details he has given therein, will afford sufficient
evidence for our conclusion.

E. scutatus, Lamk., so nearly resembles #. dimidiatus, Phil., that the latter has by
many been considered to be a variety of the former ; this point, however, will be more properly
discussed in the section devoted to the description of #. dimidiatus, Phil.

These are the only English nucleolites which at all resemble /. scutatus. Between all
the other older species and this Corallian form the distinctions are numerous and self-

350 ECHINOBRISSUS

evident. Between the newer Portland species, #. Brodeiz, Wr., and H. scutatus, a detailed
analysis will be given in the section on that species.

Locality and Stratigraphical position.—I have collected #. scutatus, Lamk., from the
Lower Calcareous Grit at Bullington-Green, near Oxford, where it was associated with
Cidaris Smithu, Wright. I have discovered it was from this same quarry that the
large type-specimen of the Cidarite figured in our Pl. II was obtained. I have gathered
it from the Lower Calcareous Grit at Filey Brig, Gristhorpe Bay, and Scarborough Castle
Hill, Yorkshire, and from the same formation at Marcham, and Faringdon, Berks. The
Yorkshire specimens I chiseled out of blocks containing Pygurus pentagonalis, Phil., and
other Calcareous Grit shells, and the Berkshire specimens were associated with Cidaris
florigemma, Phil., and Hemipedina Marchamensis, Wright. I have collected it from the
Coralline Oolite at Calne, Wilts, where it is very abundant in some beds. In one slab,
about nine inches square, obtamed from a large quarry near the town, there are
about fifty specimens, more or less imperfect, closely laid together. Like other urchins, it
appears to have been gregarious, and would be found in great numbers if its head zone
was exposed. Crdaris florigemma, Phil., Hemicidaris intermedia, Flem., Acosalenia decorata,
Haime, Pseudo-diadema versipora, Phil., lie with it in the same slabs.

My friend, Charles Pierson, Hsq., collected this species from a Pisolitic Oolitic rock—
the Lower Calcareous Grit of English geologists—about one mile from Trouville, Calvados,
where it is very abundant, and in a good state of preservation. M. Desor states that it is
found in the Oxfordien of Trouville, and Vaches-Noires, Calvados, Lannois, Ardennes, and
Chamsol, Doubs.

History.—The history of this species has been already so fully detailed in my analysis
of its synonyms, that it is unnecessary to enter into any further details on the subject.

Ecninosrissus pimipratus, Phillips. Pl. XXVI, fig. 3 a, 3, ¢. d.

CLYPEUS DIMIDIATUS. Phillips, Geology of Yorkshire, pl. 3, fig. 16, p. 127, 1829.
NucLeouires pimiptaTa. Desmoulins, Etudes sur les Echinides, Synonyme Générale,
No. 25, p. 362, 1836.
— pImip1atTus. Agassiz, Prodrome d’une Monogr. des Radiares, p. 9, 1837.
— PARAPLESIUS. Agassiz, Catalogus Systematicus, p. 4, 1840.
— pimipiatus. Morris, Catalogue of British Fossils, p. 55, 1843.
_ —_ Agassiz and Desor, Catalog. Raisonné des Echinides Annales des
Sciences Naturelles, 3° série, tome vii, p. 154, 1847.
— DIMIDIATA. Bronn, Index Paleontologicus, p. 818, 1848.
— DIMIDIATUS. Forbes, Memoirs of the Geological Survey, decade 3, description
of pl. ix, 1849.
— — D’Orbigny, Prodrome de Paléontologie, tome 1, p. 379, 1850.

FROM THE CORALLINE OOLITE. 351

NvcLEOLITES pimip1aTus. Wright (pars), Annals and Magazine of Natural Hist., 2d series,
vol. ix, p. 300, 1851.
— SCUTATUS. Wright, Annals and Magazine of Natural Hist., 2d series, vol. xiii,
p- 185, 1854.
_— — Forbes, Morris’s Catalogue Brit. Foss., 2d ed., p. 84, 1854.
ECHINOBRISSUS sCcUTATUS, var. alongse. Desor, Synopsis des Echinides Fossiles, p. 267.

Test elongated, narrower before than behind; convex above, concave below; sides
tumid ; apical disc excentral, nearer the anterior border; anal valley short and narrow,
reaching two thirds the distance between the posterior border and summit, with a
triangular undepressed space between its upper margin and disc ; posterior lobes obsolete,
posterior border only slightly grooved.

Dimensions.—Antero-posterior diameter, one inch and three tenths; transverse
diameter, one inch and three twentieths ; height, seven tenths of an inch.

Description.—This urchin is very abundant in the Coralline Oolite of Malton, from
which rock it was first figured by Professor Phillips. Unfortunately he gave no description
of the species, and his figure represented only one view of the nucleolite. Professor
Edward Forbes, who carefully studied this form, gave the following diagnosis of its
characters: “‘ JV. améitu ovato, antice rotundato, postice bilobato; dorso convexo, apice
centrali, vertice sub-centrali, postice tumido ; ambulacris anguste lanceolatis; sulco anali
profundo, ovato obtuso, superne abbreviata, lobis posterioribus tumidis ; ventre plus minusve
concavo.

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

"When Professor Forbes published the above ‘Note on British Nucleolites’ appended
to the description of pl. ix, decade 1, of the ‘Memoirs of the Geological Survey,’ he
was not aware of the existence, in our Oolites, of JV. scutatus; it is therefore probable
that his diagnosis was framed to include some forms of that species.

FE. dimidiatus has an oval outline, the upper surface of the test is uniformly
convex ; the sides and anterior border are very tumid in some specimens, and moderately
so in others ; the posterior border is rounded and only slightly grooved by the sulcus.

The ambulacral areas are narrow and lanceolate ; the single area and anterior pair are
narrower than the posterior pair, which are much longer and better developed than the
others. The poriferous zones lie in slight depressions of the test, their petaloidal portions
are wider than the homologous part of this species in /. scwtatus, and there are five to six
pairs of pores opposite each large plate.

The inter-ambulacral areas are of unequal width, the anterior pair are the narrowest,

46

352 ECHINOBRISSUS

the posterior pair are one third wider than the anterior pair, and the inter-ambulacrum is
the widest. There are about sixteen plates in each postero-lateral column, and the surface
of each is covered with numerous small tubercles (fig. 3 d), arranged in five or six
horizontal rows.

The anal valley extends about two thirds of the distance from the posterior border to
the apical disc ; it is a narrower and more shallow sulcus than the corresponding valley in
E. scutatus, and the vent opens nearer the surface. Between its upper border and the
disc there is a well-marked triangular space, in length about one third the distance between
the disc and border; the base of which is formed by the arch of the sulcus and the
lateral portions of undepressed test, and the sides, by the long, oblique, posterior
poriferous zones (fig. 3 a); this space is undepressed, and the plates composing it differ
in no respect from the plates occupying the same region in other areas. When viewed
laterally, the test of 1. dimidiatus forms a long gentle slope from the vertex to the posterior
border (fig. 3 c), and a short abrupt slope towards the anterior border ; this arises from the
excentral position of the apical disc, and the greater height of the anterior portion of the test.

The base is concave towards the centre, and tumid at the sides; the small mouth-
opening is situated opposite the apical disc; the peristome is pentagonal, and its angles
correspond to each of the ambulacral areas; the tubercles at the base are larger and more
closely crowded together than those on the upper surface; the poriferous zones are so
indistinct at the base that they appear only as faint lines radiating from the peristome.

The apical disc is very small, the madreporiform body makes a slight pyriform
prominence, and the pairs of perforated genital plates extend outwards between the
ambulacral areas.

Affinities and differences.—In its general outline this species resembles . Goldfussiz,
Desor, from the Kelloway ferrugineux of the Sarthe ; in that species, however, the vent is
nearer the border, and the test proportionately higher to its length. It so closely resembles
E.. scutatus, Lamk., that I formerly considered it a variety of the latter. It is, however,
distinguished from &. scwtatus by the following characters: the test is more elongated ;
the sides and base are more tumid; the apical disc is smaller and more excentral; the anal
valley is smaller and shallower, and rarely extends so high up the area ;_ the poriferous zones
are wider, and their petaloid portions lie in slight depressions on the upper surface; the
sides are very tumid, and they are frequently more irregular in outline and unsymmetrical
in proportions than in Z. scutatus ; the base is more concave, and its sides more tumid;
the slope of the dorsal surface hkewise, from the disc to the posterior border, is longer
and more inclined than in its nearly allied 2. scutatus.

Locality and Stratigraphical position —F. dimidiatus, Phil., is collected in considerable
abundance from the Coralline Oolite at Malton, Yorkshire, where it is associated with
£, scutatus, Lamk., Clypeus subulatus, Young, and Pygurus giganteus, Wr. The finest

FROM THE CORALLINE OOLITE. 353

specimens are those which occur in the large Freestone quarry at the east of the town.

C. W. Strickland, Esq., has obtained it in his quarry at Hildenley, near Malton, where it is

associated with Hemicidaris intermedia, Flem., Cidaris florigemma, Phil., Pseudo-diadema

hemisphericum, Agas., Collyrites bicordata, Leske, Pygurus pentagonalis, Phil., and
‘ucleolites scutatus, Lamk.

D.—Species from the Portland Oolite.
Ecarnosrissus Bropizt, Wright, nov. sp. Pl. XXXYV, fig. 1 a, 4, ¢, d, e.

Test elongated, much depressed, nearly as broad before as behind; anterior border
rounded ; posterior border angular; anal valley wide, short, limited to the lower half of
the infer-ambulacrum; apical disc small, nearly central; poriferous zones slightly
petaloidal; base undulated, from the convexity of the inter-ambulacra; mouth-opening
large, excentral, pentagonal, oblique, situated near the anterior border ; inter-ambulacrum
produced, recurved, and truncated posteriorly.

Dimensions.—Antero-posterior diameter, one inch ; transverse diameter, nine tenths of
an inch ; height, four tenths of an inch.

Description.—Urchins are so extremely rare in the Portland Oolite of England, that
the discovery of this specimen in that formation at Brill enables me to give a figure of a
nucleolite, of which I had formerly observed fragments in the same formation at Portland.
The test is unfortunately not well preserved in the Brill urchins, the matrix having adhered so
firmly to the test of the largest specimen that the surface could only be exposed by the use of
dilute acid, a process which at all times destroys the fine sculpture of the shell, and ought
never to be employed in cleaning Echinoderms but as a “dernier resort” for disclosing
structure in doubtful cases. The shell is elongated, a little wider behind than before,
the anterior border is rounded, and the posterior angular. ‘The upper surface is much
depressed and uniformly convex, forming regular curves in the length and width (fig 1 ¢, d).

The small apical disc occupies the vertex, which is anteriorly excentral; its elements
unfortunately are concealed by some closely adherent matrix, which cannot be removed.

The ambulacral areas are nearly all of the same width; the poriferous zones are
narrowly petaloid, and both rows of holes are about the same size.

The inter-ambulacral areas are of unequal width ; the anterior pair are the narrowest,
the posterior pair the widest, and the single area of intermediate width; they are all
uniformly convex, and covered with very small tubercles; the sides of the test are much
depressed, and form an angle of about 25° with the base; the margin is rounded and
flattened before, and gradually expands to within the eighth of an inch of the postero-

304 ECHINOBRISSUS

lateral ambulacra; at this point it becomes rather abruptly truncated obliquely inwards and
backwards, and is again transversely truncated at the posterior border (fig. 1 4); the upper
half of the single inter-ambulacrum is smooth and undepressed (fig. 1 @); its lower half is
occupied by the wide anal valley, with its perpendicular sides and large vent, which opens
near the surface (fig. 1, d) ; from the sides of the valley two prominent ridges descend to
the border, where they form obtuse prominences, the intermediate space being truncated
(fig. 1 a).

The base is undulated from the convexity of the inter-ambulacra (fig. 1 64), and the
depressions formed by the ambulacra as they radiate from the peristome ; the large mouth-
opening is situated nearer the anterior than the posterior border, in a slight depression of
the test ; the peristome is pentagonal, and its longest diameter is in the transverse direction
(fig. 1 4). The tubercles at the base are large, and disposed with considerable regularity ;
at the anterior margin the granules surrounding the areolas form hexagons, as shown in

(fig. 1 e). | .

Affinities and differences—This species is so entirely unlike any of its English
congeners that it cannot be mistaken for either of them, the flat, depressed upper surface,
the length of the test, which is rounded before and angular behind, the wide, short anal valley,
and large, transversely elongated mouth-opening, form a group of characters by which
it is separated from them. The length of the test and position of the anal valley,
groups it naturally with #7. Goldfussii, Desor, and #. pulvinatus, Cotteau, both from the
“ Kelloway ferrugineux ” of the department of the Sarthe. It is distinguished from the first
by the flatness of the upper surface, and the size of the anal valley, and from the latter by
the absence of the tumid sides, flat dorsum, and marginal valley, which characterise the
French urchins. The like absence of tumidity in the sides of #. Brodie distinguishes
this species from #7. dimidiatus, Phil., of the Coralline Oolite.

Locality and Stratigraphical position.—This nucleolite was collected from the Portland
Oolite at Brill, Buckinghamshire, by my friend, the Rev. P. B. Brodie, who has kindly
supplied the following note on a section of the Portland beds at that locality to accompany
my description of this beautiful new form :

«The occurrence of any of the Hchznodermata in the Portland Oolite is so rare, that it
is desirable to give a short notice of the strata at the locality whence the specimen
described by my friend, Dr. Wright, was obtained. ‘The sections at Brill, in Buckingham-
shire, are well known from Dr. Fitton’s able memoir, ‘On the Strata below the Chalk,’
and therefore I shall content myself by a very brief account of those which came more
immediately under my own inspection, which are in fact identical with those given by that
geologist. The summit of the hill is capped by the Lower Green Sand, as stated by Dr.
Fitton, but as this seems to be identical with the beds above the Portland at Great Hazeley,
whence I procured several small Paludina similar to a species described by Professor

FROM THE PORTLAND OOLITE. 355

Phillips, in his interesting paper on the ‘Iron Sands of Shotover.’* It seems probable
that those at Brill and Hazeley are of the same age, and must be classed as estuarine
deposits, belonging rather to the Wealden than the Lower Green Sand. It is as well,
perhaps, to mention these two localities, because they are not referred to in Professor
Phillips’s paper. Many years ago I found nodules of iron sand containing Paludinz in the
Vale of Wardour, in Wiltshire, and possibly a more careful examination might serve to
identify them with the estuarme sands of Shotover above mentioned.

“The top of the Portland Rock consists of a white or gray calcareous stone, with Perna
mytiloides, Lamk., Trigonia gibbosa, Sow., and Trigonia incurva, Sow., which is underlaid
by beds of hard grit divided by clay. This is succeeded by a white limestone, seen also in
the Vale of Wardour and other places ; it contains casts of Zregonias and other shells. It
is in many respects a remarkable stratum, being in parts of a soft, marly texture, which
readily crumbles to pieces when struck with the hammer. A seam of clay with broken
shells divides this from a hard, rough, calcareous stone, of a brown colour, used for building
purposes, and from this some good specimens of Perna mytiloides, Lamk., with the shell
attached, may be procured. Between this and the Portland sand there are several coarse
bands of stone, more or less calcareous and sandy, with a large preponderance of green
particles of silicate of iron ; the nodules are full of the characteristic fossils of this formation,
viz., Pecten lamellosus, Sow., Trigonia gibbosa, Sow., Astarte cuneata, Sow., Cardium
dissimile, Sow., a large Spondylus with spines, Panopea, Hxogyra, and Serpula (which
usually occur together in great perfection on the edges of the stone), a large species of
Mytilus, with Modiola, Natica elegans, Sow., Buccinum naticordes, Sow. (both of which retain
the shell in some specimens), and Cerithium Portlandicum, Sow. ‘The shells in this lower
division are numerous, and often better preserved than is usually the case in the Portland
series; this locality therefore well deserves a careful search. I have little doubt
that the Hchinobrissus came from one of these beds, overlying the Portland sand, as the
stone from whence I extracted it agrees exactly in lithological structure therewith. The inferior
shelly strata are largely used round Brill for road-mending, and I may add that I found the
two specimens of this new urchin in a heap of stone which was placed there for this
purpose, at the foot of the hill close to the quarries. The total thickness of the strata
exposed above the sand may be somewhere about twenty-five feet.

“JT am not aware whether any Bryozoa have been previously noticed in the Portland
Oolite ; but it seems worth while to mention their occurrence at Swindon, near the .
Reservoir, where I obtained a few specimens in ferruginous sand attached to single valves
of Trigonia gibbosa, Sow.

* ‘Journal of the Geological Society,’ vol. xiv, part 3, No. 55, for August, 1858,

356

NOTES

On ForriGN JURASSIC SPECIES OF THE GENUS ECHINOBRISSUS wnearuy auiiED to
BRITISH FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLIsH OoritEs.

A.—Species in which the anal valley extends to the apical disc.

EcHINOBRISSUS ELONGATUS, Agass. Syn. Hchinobrissus elongatus, Cotteau and Triger,
fchinides de la Sarthe, pl. x, figs. 8—11].

A narrow, oblong, elongated nucleolite, thin at the border, convex before, truncated,
thin, and recurved behind ; apical disc central; anal valley wide and reaching the disc;
ambulacra narrow ; zones slightly petaloidal ; base concave; mouth excentral, small, and
situated in a depression.

Dimensions.—Height, half an inch; length, one inch and one tenth of an inch;
breadth, seven tenths of an inch.

Formation.—Calcaire 4 polypiers (Bathonien) Normandy. Forest marble (Sarthe).

Collections —M. Deslongchamps. My cabinet; the specimens sent by Professor
Deslongchamps.

EcHINOBRISSUS CREPIDULA, Desor. Syn. Nucleolites crepidula, Cotteau, Hchinides Fossiles,
pl. v, figs. 4—6, p. 68.

A small elongated urchin, very flat, rounded, and narrow anteriorly, dilated and sub-
rostrated posteriorly ; anal valley elongated, deep, and broad, extending from the dise to

the border ; mouth pentagonal and sub-medial.

Dimensions.—Height, five millimetres and a half; length, fourteen millimetres ;
breadth, eleven millimétres.

Formation.—Forest marble of Chatel-censoir (Yonne), where it is abundant only as
siliceous moulds of the interior.

Collections. —M. Cotteau. Museum of Paris.

FOREIGN JURASSIC ECHINOBRISSI. 357

EcuInoprissus AMPLUS, Agass. Syn. WVucleolites amplus, Agassiz, Catal. raisonné, p. 96.

“A large species, as broad as it is long, convex above, and nearly square; posterior
border declined, thin, and emarginate ; anal valley extending to the ambulacral summit,
which is central; base concave ; mouth-opening excentral.” Desor.

Formation —* Marnes a Discoidées (Vésulien) de Wolfliswyl (Argovie) ; Val de Laufen-

Collections.—Moesch, Mus. Bale. Coll., Gressly.

ECHINOBRISSUS PLANULATUS, Roemer. Syn. Vucleolites planulatus, Roemer, Oolit.
Gebirges, pl. i, fig. 19, p. 28.

A small elongated nucleolite, remarkable for its extremely depressed dorsal surface ;
it is rounded before, truncated behind, and has the posterior border slightly emarginated.

Formation.—Upper Coral Rag of Lindner Berges (Hanover).

Collections—M. Roemer. My cabinet, specimen sent by Professor Roemer.

EcurNoprissus masor, 4gass. Syn. Wucleolites major, Agassiz, Echinoderm. Foss. Suisse,
part 1, pl. vii, figs. 22—24, p. 46.

A large, quadrate, elongated nucleolite, rounded before, enlarged behind, having the
posterior border truncated, and strongly emarginated ; base concave; mouth pentagonal,

and near the anterior margin.

Dimensions.—Height, seven tenths of an inch; length, one inch and three tenths;
breadth, one inch and three twentieths.

Formation.— Portland inférieur (Astartien Oolitique) de Laufon avec Pygurus
Hartmanni, Delémont (Jura Bernois).” Desor.

Collection —M. Gressley.

358 FOREIGN JURASSIC ECHINOBRISSI.

ECHINOBRISSUS GRACILIS, Agass. Syn. Nucleolites gracilis, Agassiz, Echinoderm. Foss.
Suisse, part i, pl. vu, figs. 1O—12, p. 44.

A small, beautiful nucleolite, rounded before, abruptly enlarged behind the disc,
emarginated and truncated posteriorly; ambulacra very narrow; anal valley wide and
deep; mouth-opening very excentral near the anterior border ; summit slightly excentral.

Dimensions.—Height, half an inch; length, seven tenths of an inch; breadth at the
widest part, nearly equal to the length.

Formation.—Portlandien inférieur (Astartien) de Reedersdorf Haut Rhin, Porrentruy.

Collection.—M. Gressley. Very rare.

B.—Species in which the anal valley does not extend to the apical disc.

Ecuinosrissus Gonprussit, Desmoulins. Syn. Hehinobrissus Goldfussi, Cotteau and
Triger, Echinides de la Sarthe, pl. xix,
figs. 1, 2, p. 86.

A small nucleolite, rounded before, sub-truncated and slightly dilated behind ; upper
surface convex and inflated ; much sloped from the summit to the posterior border; base
flat, vertex excentral and anterior; anal valley short, wide, and deep, arched above,
expanded below, extending one third of the distance between the border and disc; vent
elliptical near the surface ; mouth-opening anteriorly excentral; peristome pentagonal.

Dimensions.—Height, half an inch ; length, nineteen twentieths of an inch; breadth,
nearly eight tenths of an inch.

Formation.—Kelloway ferrugineux, Montbizot, Department of the Sarthe, Largues
(Haut Rhin) ; Launoy (Ardennes) ; Htage Oxfordien.

Collections.—MM. Cotteau and Triger.

ECHINOBRISSUS PULVINATUS, Cotteau, Hichinides de la Sarthe, pl. xix, figs. 3, 4, p. 87.

A moderate sized, oblong nucleolite, round before, sub-truncated behind, thick and
inflated at the borders, depressed at the upper surface; base sub-concave and slightly
undulated ; apical dise sub-central, nearer the anterior border; anal valley far removed

FOREIGN JURASSIC ECHINOBRISSI. 359

from the summit, and forming a sulcus in the posterior border ; mouth-opening small and
excentral.

Dimensions.—Height, eleven twentieths of an inch ; length, one inch and one
twentieth ; breadth, nine tenths of an inch.

Formation —Kelloway ferrugineux, near Mamers, Sarthe ; very rare.

Collections —MM. Michelin and Cotteau ; my cabinet.

Ecuinosrissus Icaunensts, Cotfeau. Uchinides Foss. de PYonne, pl. xlv, figs. 6—8,
p. 326.

Test elongated, depressed, narrow before, wider behind ; apical disc excentral, nearer
the anterior border ; anal valley short, wide, extending only half way between the border
and disc; vent large and elliptical; base concave ; mouth-opening excentral, nearer the
anterior border ; peristome pentagonal.

Dimensions.—Height, four tenths of an inch ; length, one inch and one tenth; breadth,
nine tenths of an inch.

Formation.—Kimmeridgien (‘Calcaire des environs de Tonnerre et de Chablis),
Gray (Haute Marne),” Cotteau; very rare.

Collections—M. Cotteau, M. Rathier,

EcuINoBRIssus TRUNCATUS, Desor. Synopsis des Echinides Fossiles, p. 268.

A new species with a very elongated form, neatly uniform in width throughout,
and slightly enlarged behind ; anal valley, supra-marginal ; the entire length of the sulcus
seen only when the posterior border is examined.

Formation.—* Portlandien supérieur (Virgulien) d’All prés Porrentruy. 'Trés rare.”

Desor.
Collection.— Mus. Bale.

47

360

Genus—CLYPEUS, Klein, 1734.

This genus includes all the large discoidal urchins, with petaloid ambulacra, in
which the vent opens at the upper surface into an anal valley; the dorsal portions of the
poriferous zones are widely petaloidal; the ambulacral summit is central, or excentral,
and when this is the case, the excentricity is always towards the posterior border; the
elements of the apical disc are closely soldered together, there are two pairs of perforated
genital plates, one single imperforate plate, and five ocular plates, the orbits are in general
marginal and visible, and the spongy madreporiform body occupies the centre of the disc.

The base is flat, concave, or undulated, in different species ; the mouth-opening is
small and lodged in a depression, which is either central or sub-central; the peristome is
surrounded by five oral lobes, formed by the terminations of the inter-ambulacra.

This group differs so slightly in all its essential characters from the genus Hehinobrissus,
that I formerly agreed with my late friend, Professor Forbes, to include all the species of
Clypeus in the Lamarckian genus WVucleolites. After amore detailed study of the compara-
tive anatomy of their tests, taking into consideration the magnitude and development of
the long wide petaloidal poriferous zones, and the relation these parts had to the internal
organs, I have determined to retain the genus.

Like Hehinobrissus, the genus Clypeus includes two types of structure; in the first,
the anal valley extends from the apical disc to the posterior border, this section includes
the majority of the species, having for its type Clypeus Plotw, Klem. In the second,
the anal valley does not extend to the disc, but is separated therefrom by a greater or
less undepressed portion of test. The types of the second section are Clypeus Hugii, Ag.,
and Clypeus subulatus, Young.

All the species are limited to the Oolitic rocks, and they had their greatest develop-
ment in the seas which deposited the lower division of the Jurassic series; as the Inferior
Oolite, zone of Ammonites Parkinsoni; the Bath Oolite group, and the Cornbrash
contain the most of the species. I know of none in the Oxford Clay, and the Coral Rag
contains only one.

CLYPEUS. 361

Suction A. Anal valley extends from the disc to the border.
A. Species from the Inferior Oolite.
Cryreus Puotu, Klein. Pl. XXVIII and XXixX.

Potar Srone. Plot, History of Oxfordshire, tab. ii, figs. 9 and 10, 1677.
EcHINITES. Lister, Lapidibus Turbinatis, p. 224, pl. vii, fig. 27, 1678.
— CLYPEATUS. Llhwyd, Lithophylacii Britannici Ichinographia, tab. xiii, p. 48,
No. 971, 1698.
ECHINUS DISCOIDES. Morton, Natural History of Northamptonshire, p. 233, 1712.
CLyPrus PLorit. Klein, Natural. Disposit. Echinodermat., tab. xii, p. 22, 1734.
— —_ Leske, Additamenta ad Kleinii Echinodermatum, p. 157, 1768.
ECHINUS SINUATUS. Linneeus, Systema Nature, by Turton, vol. iv, p. 144, 1801.
CLYPEUS SINUATUS. Parkinson, Organic Remains, vol. ili, p. 24, pl. ii, fig. 1, 1811.
GALERITES UMBRELLA. Lamarck, Animaux sans Vertébres, tom. iii, p. 23, No. 15, 1816.
— PATELLA. Lamarck, Animaux sans Vertébres, tom. ili, p. 23, No. 14, 1816.
ECHINITES SINUATUS. Schlotheim, Petrefacktenkunde, i, p. 310, 1820.

NUCLEOLITES PATELLA. Defrance, Dict. des Sciences Naturelles, tom. xxxv, p. 213, 1825.
EcHINOCLYPEUSUMBRELLA. De Blainville, Diction. des Sciences Naturelles, tom. Ix, p. 189,

1830.
— PATELLA. De Blainville, Dict. des Sciences Naturelles, tom. lx, p. 189, 1830.
GALERITES PATELLA. Deslongchamps, Encyclopéd. Méthodique, pl. cxliii, figs. 1, 2.

— — Id., Enc., tom. ii, p. 434, No. 14.
ECHINOCLYPEUS UMBRELLA. De Blainville, Manuel d’Actinologie, p. 208, 1834.
CLYPEUS PATELLA. Agassiz, Prodrome, Mém. Soc. d’Hist. Nat. Neuchatel, tom. i,
p. 186, 1835.
— = Agassiz, Echinodermes Fossiles de la Suisse, 1st part, p. 56,
tab. v, figs. 4—6, 1839.
oo = Morris, Catalogue of British Fossils, p. 50, 1843.
— SINUATUS. Morris, Ibid.
— ANGUSTIPORUS. Agassiz, Cat. raisonnée, An. Sc. Nat., tom. vii, p. 156, 1847.
a EXCENTRIcUS. M‘Coy, Annals and Magazine of Natural History, p. 417, 1848.
NUCLEOLITES SINUATUS. Forbes, Memoirs of the Geol. Survey, decade i, 1849.
— _ Wright, Annals and Mag. of Nat. Hist., vol. ix, p. 306, 1851.

CLYPEUS PATELLA. Bronn, Lethza Geognostica, Band. ii, p. 152, tab. xv, fig. 9,
1852.

NUCLEOLITES sINUATUS. Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 84,
1854.

Ciyrrus PLotil. Salter, in Hull’s Memoirs of the Geological Survey, 1857.

CLYPEUS SINUATUS. Desor, Synopsis des Echinides Fossiles, Pl. XXXV, p. 276, 1858.

Dimensions.—Height, one inch and seven tenths; antero-posterior and transverse
diameters nearly equal, measuring four inches and four tenths.

362 CLYPEUS

Description.—This well-known and widely distributed urchin was first figured by
Dr. Plot in his ‘ History of Oxfordshire,’ tab. ui, figs. 9, 10, and was accompanied with the
following quaint remarks :

“Of Brontie, therefore, or Ombrie (call them which you will), we have several sorts
in Oxfordshire, which yet all agree in this, that they are a sort of solid irregular hemi-
spheres; some of them oblong, and having somewhat of an oval; others either more
elevated, or depressed on their bases. All of them divided into five parts, most times
inequal, rarely equal, by five rays issuant from an umbilicus or center, descending from it
down the sides of the body, and terminating again somewhere in the base. They are
never found in beds together, like some other formed stones, nor that I have yet heard of
(says the ingenious Mr. Ray*) in great numbers in one place: but in the latter I must
take leave to inform him, that though I think it in the main to be true, yet that at
Tangley Fulbrook, and all about Burford, they are found in such plenty, that I believe it
were easy in a little time to procure a cart-load of the first sort of them, carefully
exhibited in tab. ii, figs. 9, 10, whose innermost texture, though it seem to be nothing
more than a coarse rubble-stone, yet is thinly cased over with a fine laminated substance
(the plates lying obliquely) much hke Lapis Judaicus. In form they are flat, depressed
upon the basis, in colour generally yellow, their rays made of a double rank of transverse
lines, with void spaces between the ranks, visible enough on the top of the stone (fig. 9),
but not so distinguishable on the bottom (fig. 10); the whole body of the stone, as well
as the spaces included within the rays, being elsewhere filled with annulets much more
curiously wrought by nature than by the tool of the graver.

“The center of these rays, by Pliny called modiolus, by Aristotle umbilicus, is never
placed on the top of the stone, but always inclining to one side, as that at the bottom does
to the other; the axis lying obliquely to the horizon of the stone. Which gave occasion
to a learned Society of Virtuosi, that during the late usurpation lived obscurely at
Tangley, and had then time to think of so mean a subject, by consent to term it the Polar-
stone, having ingeniously found out by clapping two of them together, as suppose the
figs. 9 and 10, that they made up a globe, with meridians descending to the horizon, and
the pole elevated, very nearly corresponding to the real elevation of the pole of the place
where the stones are found.”

Klein} gave the following diagnosis of this urchim: ‘Species 1, Plotii; maximus discum
referens; Burfordinensis, Hist. Oxon., tab. 1, figs. 9, 10. Luydi prope Fulbrock in agro
Oxon. Integra testa intra demissos circulos stellata, superficiem quinque, taenize profunde
duplicate ac crenate et unus altus sulcus levis in undecim, basin vero quinque sulci
angustiores in totidem segmenta dividunt.” In tab. xii, this author figured a large

* «Observations Topograph.,’ p. 116.
+ Plot’s ‘History of Oxfordshire,’ pp. 90, 91.
t ‘Naturalis Dispositio Echinodermatum,’ p. 22.

FROM THE INFERIOR OOLITE. 363

Clypeus which was communicated to him by Dr. Heucher from the Royal Cabinet of
Dresden ; this urchin was described by Leske* in his additions to Klein’s Monogragh as
a distinct species, under the name Clypeus sinuatus ; by subsequent authors, C. Plotiz, Klein,
with the author’s reference to Plot’s figure as the type of the same, is omitted. Although
Leske described both species and pointed out the diagnostic differences which he supposed
to exist between them, nevertheless Klein’s reference to the type of the English species has
been overlooked, and Leske’s name given to this urchin. Lamarckt introduced still further
confusion into the subject by describing the flattened varieties of Clypeus Plotit, Klein,
under the name Galerites patella, and this new specific synonym was adopted by Defrance,
Deslongchamps,§ De Blainville,|| and Agassiz,§ and is retained by most Continental
palzontologists at the present time. As it has been one of my objects to trace the
true history of every species described in this work, even at the risk of disturbing a
name which has passed unchallenged for nearly a century, justice to Klein renders
it imperative that his name should be retained to the urchin which was first figured
by Dr. Plot, and that of Clypeus sinuatus, Leske, to the specimen contained in the
Dresden collection; should a further examination of that urchin show that it is only
a tumid variety of C. Plotiz, Klein, the priority of the latter will still entitle it to be
retained as the name of this species.

Although this large buckler-shaped urchin has been well known to naturalists for
nearly two centuries, nevertheless no good figure of the test, with details of its structure, has
been given until now; this is the more remarkable, when the beauty and abundance of the
species is considered, together with its importance in Oolitic geology.

The test exhibits many varieties of form and outline ; some of these have received specific
names and descriptions by different authors, of which Clypeus angustiporus, Agass., and
Cl. excentricus, M‘Coy, are examples. This urchin attained its most typical form and
best development in the seas which deposited the beds constituting the zone of Ammonites
Parkinsoni of the Inferior Oolite ; the specimens found in the Stonesfield Slate, Great Oolite,
and Cornbrash are in general smaller, and deviate more or less from the Inferior Oolite forms.

The ambulacral areas on the dorsal surface are narrowly lanceolate ; the anterior pair,
and single area, are about the same width; but the posterior pair are wider; they are all
more or less slightly flexed (Pl. XXVIII, fig. 1 a); at the base they form narrow
depressed bands, which radiate from the mouth to the circumference (fig. 1 4), and give
a stellate character to the base of the test.

* © Additamenta ad Kleinii Dispositionem Echinodermat
+ ‘Animaux sans Vertébres,’ tom. ili, p. 23, No. 14.

t ‘Diction. des Sciences Naturelles.’

§ ‘Ecyclopéd. Méthodique.’

|| ‘Diction. des Sciences Naturelles.’

q ‘ Echinodermes Fossiles de la Suisse.’

364 CLYPEUS

The poriferous zones are broadly petaloidal on the dorsal surface; at the border the
pores are as closely approximated as they are at the base (Pl. XXIX, fig. 1 a, 6); about
two lines up the sides they become abruptly apart, and continue so throughout the zones ;
they again gradually approximate in the vicinity of the disc (fig. 1 a, 4); the holes of the
inner row are round, those of the outer row are slit-like, and the outer and inner holes of
each pair are united by fine fissures (Pl. XXIX, fig. 1c); the mtermediate septa having a
single row of small granules on their surface; at the base the pores forming a pair are
small, and closely approximated; the zones are very narrow, and form wavy lines, in
which the bigeminal pores are placed at intervals apart, sometimes they are disposed
in rectilineal order, and sometimes arranged in triple oblique pairs; at Pl. XXIX,
fig. 1 g, I have represented this arrangement of the pores in one of the basal
zones, where each small ambulacral plate is seen to be perforated by a pair of pores. As
the ambulacral plates are much narrower on the upper surface than they are at the
base, the pores are more numerous, and more closely approximated on the dorsal surface,
where there are from eight to ten pores opposite each large plate (Pl. XXIX, fig. 1 c).

The inter-ambulacral areas. are of unequal width, the anterior pair are the narrowest,
the single area is the widest, and the posterior pair of intermediate dimensions; there
is often a slight depression down the centre of each area in the line of the median suture,
which, with the flat petaloidal depression formed by the poriferous zones, produces a series
of undulations on the upper surface of the areas (Pl. XXIX, fig. 1 4). ‘The single inter-
ambulacrum is deeply cleft by the anal valley, which commences narrow at the disc,
expands towards the middle, and still more so at the border (Pl. XXIX, fig. 1 a). The
sides are vertical, and the vent is seen at the extremity of the channel, and is figured in
shadow in fig. 1 @ The border of the test forms a series of graceful undulations,
from the prominence and convexity of the inter-ambulacral and the narrowness of
the ambulacral areas. (Pl. XXIX, fig. 1 @ and fig. 1 6, shows the undulation of the
border.)

The tubercles on the upper surface are small, and nearly equal in size throughout
both areas; those in the ambulacra are arranged in oblique V-shaped rows, and those on
the inter-ambulacral plates in nearly horizontal rows, of which there are five or six on
each large plate (Pl. XXIX, fig. 1 c). At the base, they are more unequal im size, and
larger than on the upper surface; in the middle of the area they are smaller; at the sides
they are larger, and sometimes the large tubercles are perforated, as shown at fig. 1 e and
fig. 1 f They are surrounded by deep areolas, and between these depressions the
surface of the plates is covered with fine granulations (fig. 1 e). It is right to remark,
that in the specimens I have hitherto examined the perforation of the large basal tubercles
is an exceptional, rather than a general character.

The apical disc is large, and lies in a depression behind the vertex. Its plate-elements
are rarely seen separate, except in specimens which have been decomposed, as in
this urchin, the genital and ocular plates are all firmly anchylosed together from early age ;

FROM THE INFERIOR OOLITE. 365

the four ovarial holes project into the inter-ambulacral spaces, and the five ocular holes are
seen at the apices of the ambulacra (Pl. XXIX, fig. 1d). The madreporiform body
occupies the centre of the disc, and presents a fine spongy structure on its surface.

The base is flat, or slightly concave; the basal portions of the inter-ambulacral areas
are convex, and separated from each other by narrow, depressed ambulacral valleys
(Pl. XXVIII, fig. 1 4), which radiate in straight lines from the mouth to the border, the
margin of the ambulacra being defined by the narrow poriferous zones.

The mouth is excentral, and situated nearer the anterior than the posterior border
(Pl. XXVIII, fig. 1 4). The peristome is surrounded by five prominent oral lobes,
which are separated from each other by the depressed ambulacra, as they radiate from
the mouth. At Pl. XXIX, fig. 1 2, another view is given of this-quinque-lobed opening.

There is a very marked distinction in the varieties of Clypeus Plotiz collected from the
Inferior Oolite and the Great Oolite; so much so, that they have been considered, by good
local observers, to belong to two distinct species. On this point my excellent friend, the
Rev. A. W: Griesbach, remarks—

‘* Clypeus Plotii.—I have two urchins on the table, both said to be this species. One
of them is a very good specimen from the Great Oolite, Kingsthorp, the other an Inferior
Oolite specimen from Rodborough Hill. These urchins appear to belong to two distinct
species, for I think their differences can hardly be less than specific. I have no doubt but
you have specimens both from the Great and Inferior Oolite. Pray compare them. I
will just say, meanwhile, that in the Inferior Oolite specimen the apical disc is all but
central, while in the Great Oolile one it is much nearer the posterior margin. In the
Great Oolite specimen the apices of the ambulacra are deeply sunk below the plane of the
test, while in the Inferior Oolite specimen they are cz the same plane as the test. And, in
the Inferior Oolite specimen, the region of the shell which contains the anal furrow is very
tumid, and towards the disc nearly as high as the highest part of the shell; in the Great
Oolite specimen the posterior part of the test corresponding is extremely and abruptly
depressed and flattened. In general form the Inferior Oolite specimen is high and
spherical, the Great Oolite specimen low and flattened. May not these two forms
eventually prove to be C. siwuatus, Leske, C. Plotiz, Klein, respectively >”

Afimties and differences—This large discoidal urchin is so distinct from all other
congeneric forms that it can scarcely be mistaken for any of them. Its nearest affinities
are with Clypeus Michelini, Wr., and Clypeus Miilleri, Wr.

It is distinguished from Clypeus Michelini by its greater convexity, the wideness of the
poriferous zones, the size of the tubercles, and the width of the anal valley. From Clypeus
Miilleri, Wr., by its orbicular outline, and the absence of the produced, deflected, and
truncated posterior border, so characteristic of that species. From Olypeus Hugii, Ag., it
is distinguished by the extension of the anal valley from the dise to the border; whereas in
that species a portion of undepressed test always separates the disc from the valley.

366 CLYPEUS

From Clypeus subulatus, Young, itis distinguished by its orbicular outline and anal valley ;
in that urchin the outline is oblong, and the anal valley quite short and marginal. ‘The
height and convexity of Clypeus Agassizii, Wr., with its shallow anal valley and inflated
test, prevent the possibility of mistaking Clypeus Plotit, K1., for that urchin, which re-
places it in some of those regions where the latter is absent.

Locality and Stratigraphical position.—The metropolis of Clypeus Plotii is the Trigonia
grit of the Inferior Oolite, in the zone of Ammonites Parkinsoni; it is extremely
abundant in some localities, but rare in others; over the central parts of the Cotteswold
Hills it is found in great numbers; where its bed crops out at the surface, as near
Naunton Inn, a cartload of weathered Clypei might sometimes be collected. My best
specimens were obtained from near Stow-in-the-Wold. I have likewise collected beautiful
examples at Rodborough Hill, Scar Hill, Shurdington Hill, Leckhampton Hill, Cleeve
Hill, and at Cubberley, Cowley Wood, Pen Hill, Little Rissington, Adlestrop, Northleach,
and Hampen, Gloucestershire; in the same zone near Burford, and Sarsden, and in the
Stonesfield Slate at Stonesfield, Oxon. Mr. Lycett obtained one specimen from the
Fuller’s-earth, at Minchinhampton Common; it is found likewise in the Great Oolite at
Minchinhampton, Gloucestershire; Kiddington, Oxon; and Kingsthorp, Northampton.
Mr. Macneil, after many years’ collecting, found only two specimens in the Cornbrash
at Trowbridge, Wilts, both of which are now in my cabinet.

The Foreign distribution of this species, according to M. Desor, is “Oolite vesulienne du
Kornberg prés Frick et Buren prés Gensingen (Argovie), Muttenz (Bale), Porrentruy,
Plasne pres Poligny, St. André prés Salins.

“Grande Oolite de Boulogne-sur-Mer, Chayal (Ardennes), Montanville, Flincy (Meuse),
Noviant, Besancon.” '

Cuyprus aLtus, M‘Coy. Pl. XXVII, fig. 1 a, 6, ¢, d, e, f.

CLYPEUS aLTUS. MCoy, Ann. and Mag. of Nat. Hist. 2d ser., vol. ii, p. 417, 1848.
NUCLEOLITES ALTUS. Forbes, in Morris’s Catalog. of Brit. Foss., 2d ed., p. 83, 1854.
Ciypnus Davousrranus. Desor, Synopsis des Echinides Fossiles, p. 55, 1855.
= ALTUS. Wright, Stratigraph. Distrib. Ool. Echinoder., British Association
Reports, 1856.
— Davoustianvs. Cotteau, in Davoust, Note sur les foss. spec. de la Sarthe, p. 7,
1856.
= — Cotteau, Note sur quelques Oursins de Ja Sarthe, Bull. de Geol.
Soc. de France, 2° sér., t. xiii, p. 650, 1856.
= — Cotteau and Triger, Echinides du départ. de la Sarthe, pl. xii,
figs. 1—7, p. 62, 1858.

Test sub-circular, broader than long, upper surface evenly convex, high, and sometimes
sub-conical; base concave, very much undulated, from the extreme tumidity of the basal

FROM THE INFERIOR OOLITE. 367

portions of the inter-ambulacra ; apical disc central; poriferous zones petaloid on the
upper two thirds of the dorsal surface ; lower third, and basal portion, with parallel rows
of unconnected pores; anal valley long, narrow, deep, extending from the disc to the
border, fissure-like above, and slightly expanded near the margin ; single inter-ambulacrum
much deflected and beak-like, truncated at its extremity; mouth-opening small, sub-
eentral, lodged in a deep depression, peristome surrounded by five oral lobes. Greatest
diameter of the shell across the middle of the postero-lateral inter-ambulacra.

Dimensions.—Height, one inch and one fifth; antero-posterior diameter, two inches
and six tenths; transverse diameter, two inches and nine tenths.

Description.—This beautiful Clypeus attains considerable dimensions, and preserves
through all the phases of its development the specific characters enumerated in our
diagnosis. It is remarkable for having the upper surface evenly convex, much elevated,
or even sub-conical ; it is likewise broader across the postero-lateral ambulacra than it is
long, its base is more concave, the inter-ambulacral segments of this region are more
tumid, and the outline of the basal margin more undulated (fig. 1 c, d), than in any other
species.

The ambulacral areas are narrow at the margin, slightly enlarged at the upper third,
and lanceolate at the apex. The poriferous zones in the upper.two thirds of the dorsal
surface are slightly petaloid; in the lower third the pores are small, parallel, equal, and
unconnected (fig. 1 @, ¢); in the petaloid portion, the pores of the inner row are round,
those of the outer row are slit-like and oblique (fig. 1 e); the ambulacral plates are very
narrow, there being seven, with a corresponding number of pairs of holes, opposite each
large inter-ambulacral plate (fig. 1 e).

The inter-ambulacral areas are of unequal width, the anterior pair are the narrowest,
the posterior pair the widest, and the single area of intermediate dimensions; they
are almost uniformly convex on the upper surface, and present very great inequalities at
the base, more so, in fact, than in any other species of the Ecurnosrissipz. The single
inter-ambulacrum is short, curved, much deflected, and truncated ; it is deeply cleft by the
anal valley, which extends from the apical disc to the margin ; this sulcus is in the form of
a deep fissure, with vertical parallel walls in the upper half of its length, but moderately
expanded in the lower half (fig. 1 @ and d).

The small, narrow, and elongated apical disc is well preserved in most of my
specimens, and is situated near the centre of the test, immediately behind the vertex ; it
is composed of two small, anterior, perforated genitals (fig. 1), and two larger posterior
perforated genitals, with a single, long, imperforate genital plate, which descends into the
narrow anal valley; the spongy madreporiform body rises from the surface of the right
anterior genital, and extends into the centre of the disc; the five small ocular plates

A8

368 CLYPEUS

have marginal eyeholes, and the surface of all the discal elements is covered with fine
granulations.

This urchin, when viewed in profile, presents a considerable undulation around the
border (fig. 1 ¢ and @), occasioned by the narrowness of the ambulacra, and the extreme
tumidity of the marginal and basal portions of the inter-ambulacra. It is as
remarkable for the concavity of its base, and the cushion-like structure of its basal
inter-ambulacra, as for the evenness and convexity of the dorsal portions of the same seg-
ments : the basal portions of the antero-lateral inter-ambulacra are small, and moderately
convex (fig. 1 ¢ and @), the postero-lateral pair are very prominent and tumid, and the
single inter-ambulacrum is angular, deflected, and truncated at its extremity.

The small mouth-opening lies in a deep sub-central depression (fig. 1 4), and the
peristome is surrounded by five small oral lobes; the basal portions of the ambulacra
are narrow, and the poriferous zones so small and indistinct that the pores, even with a
lens, are seen with difficulty; as they approach the mouth they increase in size and
number, and form a series of triple oblique rows in the five petal-like expansions which
radiate from the mouth (fig. 1 8).

The small tubercles are in general arranged in four horizontal rows on each plate (fig.
le); they are very uniform in size, and surrounded by sunken areolas, the tubercles
at the base and border are larger than those of the upper surface; all the intermediate
surface of the plates is covered with fine homogeneous granules, microscopic in size, but
regular in their arrangement.

Affinities and differences—This species resembles some of the smaller varieties of
Clypeus Plots, Klein, but is readily distinguished from these, and from all congeners,
by its greater proportional breadth across the postero-lateral inter-ambulacra, the narrow-
ness and fissure-like character of the anal valley, the remarkable undulations of the
border, the tumidity of the basal inter-ambulacral cushions, and the concavity of the base.
It resembles Clypeus Muiilleri, Wr., m the shortness of the petaloid portion of the dorsal
ambulacra, and the narrowness of the anal valley; but the oblong form of Clypeus Miilleri,
the flatness of its base, and the depression of its dorsal surface, form diagnostic distinctions
between them. In the narrowness of its ambulacral petals it resembles Clypeus Michelini,
Wr., but the flat dorsal and basal surfaces of that species form distinctive characters by
which the two urchins are readily distinguished from each other.

Locality and Stratigraphical position—I have collected this urchin from the
Inferior Oolite of Dorsetshire only, in the upper ragstones of that formation, appertain-
ing to the zone of Ammonites Parkinsoni, as defined in the chapter on the Strati-
graphical distribution of Oolitic Echinodermata. I have found it at Burton-Bradstock,
and Walditch Hill, near Bridport, associated with Ammonites Parkinsoni, Sow., Ammonites

FROM THE INFERIOR OOLITE. 369

subradiatus, Sow., Stomechinus bigranularis, Lamk., Holectypus hemisphericus, Desor,
Collyrites ovalis, Leske, and Collyrites ringens, Desml. It appears to take the place of
Clypeus Plotit in the Parkinsoni zone of Dorsetshire, just as Holectypus hemisphericus,
Desor, replaces in the same rock in Dorsetshire Holectypus depressus, Lamk., which is so
abundant a fossil in this zone of the Inferior Oolite in the Midland counties of England

and so rare in the South.

History.—This, urchin was first described by Professor M‘Coy, in his paper on ‘ New
Mesozoic Radiata; the species was for a time overlooked, as no figure was given with the
description ; Professor M‘Coy subsequently kindly sent me pen-and-ink outlines of all the
species described in that memoir, by which I was enabled to identify the forms supposed
to be new. This Clypeus has recently been beautifully figured, and well described as
Clypeus Davoustianus, by my esteemed friend M. Cotteau, in his valuable monograph on
the ‘Hchinides of the Sarthe.? It was not included in my memoir on the ‘ Cassidulidee of
the Oolites, as at the time I could not find a specimen to study. Since the publication of
that Prodrome I have collected a very fine series of this species; a comparison of the
figures ‘given by M. Cotteau, and the one now published in our Pl. XXVIL, fig. 1, leaves
no doubt as to the identity of the Sarthe Clypeus Davoustianus, Cot., and the Dorsetshire
Clypeus altus, M‘Coy.

Crypzus Micuenini, Wright. Pl. XXX, fig. 2 a, 4, ¢, d.

Nuctreouites Micuetrni. Wright, Ann. and Mag. of Nat. Hist., 2d series, vol. xiii, p. 161,
pl. xu, fig. 6, 1854.
— —_ Forbes, in Morris’s Catalogue of Brit. Fossils, 2d ed., additional
sp. of Echinodermata, 1854.
— — Wright, Report Oolitic Echinod., Brit. Assoc. Reports, 1857.
Cixypnus MIcHELINI. Desor, Synopsis des Echinides Fossiles, p. 277, 1858.

Test circular or oblong, discoidal and much depressed, posterior border produced,
truncated and slightly deflected in old individuals ; ambulacral areas narrowly lanceolate ;
poriferous zones narrow, only slightly petaloid on the dorsal surface, vertex and apical
disc nearly central; anterior half of the upper surface convex, posterior half much declined ;
anal valley narrow above, diverging below, extending from the apical disc to the border ;
base flat, slightly concave ; mouth excentral, peristome with five small lobes ; postero-lateral
inter-ambulacral areas slightly tumid at the base.

Dimensions.—Height, nine tenths of an inch; antero-posterior diameter, three inches
and a quarter ; transverse diameter, two inches and one fifth.

Description.—The outline of this urchin varies in different individuals, and likewise

370 CLYPEUS

in the same individual at different periods of life; its most typical form is oblong,
convex anteriorly, produced and truncated posteriorly, and enlarged in the region of
the postero-lateral inter-ambulacra; in others the circumference is nearly circular, and in
some few transversely oval; the first form is, probably, characteristic of adult life, as the
elongation and truncation of the single inter-ambulacrum are markedly shown in the only
two large specimens I have seen of this rare species. In all the test is very flat;
the anterior half is gently and nearly equally convex, and the posterior half much ©
declined towards the posterior border. The ambulacral areas are narrow, the anterior one
most so; the antero-lateral and postero-laterals are about the same width; they have a
lanceolate form, and are composed of very narrow plates; about three tenths of an inch
above the margin, the pores slightly diverge, and continue about the same width
apart until they approach the apical disc; the distance between the rows of pores in
this species is less than in any other known Clypeus, and forms one of its diagnostic
characters; in all the specimens I have examined the ambulacral areas are likewise
slightly elevated above the general surface of the test. The inter-ambulacral areas
are of unequal width, the antero-lateral pair are the narrowest, they are, however, about
nine times the width of the anterior single ambulacral area; the postero-lateral pair
are three tenths of an inch wider than the antero-laterals, and the single inter-ambulacrum
is about the same width as the latter. The anal valley extends from the apical disc to
the posterior border; it is very narrow, with deep perpendicular sides above, which
become shallow and expanded below; the postero-lateral inter-ambulacra are enlarged at
the margin ; the single inter-ambulacrum is considerably produced, its posterior border is
broadly truncated and slightly deflected, within which the expanded sides of the anal
valley are excavated.

The base is nearly flat; the elevations are produced by the prominence of the
postero-lateral inter-ambulacra, and the deflection of the single inter-ambulacrum. The
small mouth-opening is excentral, and placed nearer the anterior than the posterior border ;
the peristome is surrounded by five. small oral lobes, which make inconsiderable promi-
nences at the base. ‘The apical disc is small, and absent in most of my specimens; in
one only is it preserved. The genital plates are nearly equal sized; the anterior and
posterior pair are perforated, and the single plate is imperforate. The madreporiform
tubercle rests on the right anterior plate, and extends into the middle of the disc. The
ocular plates are small, and firmly wedged between the disc and summits of ambulacra;
the eyeholes are large, and, with the four genital holes, form a circle of perforations
around the circumference of the disc.

Affinities and differences.— Clypeus Michelini, in its oblong form, truncated posterior
border, and narrow anal valley, resembles C. Jilleri, Wr.; but is readily distinguished
from the latter by the form, narrowness, and structure of the ambulacral areas ; in C.
Miullert they are expanded and petaloid, and in C. Michelini they are narrow and lanceo-

FROM THE GREAT OOLITE. 371

late; the pores at no point are at any great distance apart; the anal valley in both species
extends from the apical disc to the margin, but in C/ypeus Michelini it is more expanded
below and deeper above than in Clypeus Miilleri.

I have now before me Clypeus angustiporus, Ag., from a coarse Oolitic rock (Brad-
fordien ?) near Metz, collected by M. Terquem, and kindly sent me by M. De Loriére ; this
urchin appears to be a variety of Clypeus Plotii ; from which C. Michelini differs in many
‘particulars. In the French urchin the apical disc is excentral, the anal valley wide
above and not much expanded below, the ambulacral areas are narrow, and the test
declines gradually from the vertex to the anterior border, which forms a rather acute angle
the base is undulated, and the mouth-opening nearly central; these characters distin-
guish it from our urchin.

Clypeus Michelini differs so widely from all the varieties of Clypeus Plotii with
which I am acquainted, that it cannot possibly be mistaken for either of them, if proper
care be taken when a comparison is made between them.

Locality and Stratigraphical position —I have collected this species chiefly from the
Freestone beds of the Inferior Oolite at Wallsquarry and Nailsworth, Gloucestershire ;
the specimens figured in PI. XXX, were cut out of the centre of a block of building
stone; the Oolitic grains were imbedded in the plates of the test, and have in some
measure injured their surface. I found two small specimens in the zone of Ammonites
Humphriesianus, in a sandy bed of this middle division of the Inferior Oolite at Cleeve
Hill, near Cheltenham, where it was associated with Ammonites Brongniarti, Sow.,
Am. Humphriesianus, Sow., Am. Brocchii, Sow. Mr. Reed, of York, collected several
specimens germinans from the Inferior Oolite at Whitwell, Yorkshire ; one of these, kindly
given me by that gentleman, I have figured in P]. XXVI, fig. 2. It was associated with
Stomechinus germinans, Phil., Trigonia costata, Sow., Gervillia Hartmanni, Minst., and
other Inferior Oolite shells. .

B. Species from the Great Oolite.

Cryrerus Mizrurri, Wright. Pl. XXXIII, figs. 1, 2, 3, 4, 5, 6.

Nucieoxites SoLopurinus. Wright, Ann. and Mag. of Nat. Hist., 2d ser., vol. ix, p. 305,
1851.
— — Forbes, in Morris’s Cat. of Brit. Foss., 2d ed., p. 84, 1854.
— — Wright, Report on Brit. Ool. Echinodermata, Brit. Assoc.
Report, 1857.

Test oblong, posterior border much produced, deflected, and truncated ; ambulacral areas
largely petaloidal, with their apices closely approximated ; apical disc and vertex excentral

372 CLYPEUS

posteriorly, anal valley narrow, acutely lanceolate, with vertical walls, extending from the
disc to the border; base concave, mouth-opening sub-central, peristome surrounded by
five prominent oral lobes.

Dimensions..-—Large specimen from the Forest Marble. Antero-posterior diameter,
three inches and a quarter; breadth, three inches and three tenths.

Average-sized specimen from the Great Oolite. Height, eight tenths of an inch ; antero-
posterior diameter, two inches and a quarter; breadth, two inches and three twentieths.

Description.—This beautiful Clypeus was first found by my esteemed friend
S. P. Woodward, Esq., in the Great Oolite near Cirencester, and was referred by him to
Clypeus Solodurinus, Ag. In this opinion I formerly concurred, and described it under
that name in my memoir on the ‘ Cassidulidz of the Oolites, already referred to in the
synonyms of this species. Having discovered a marly vein in the Great Oolite which
contained a number of specimens, I had an opportunity of studying this urchin in
different stages of development; from this examination I ascertained that our original
determination could not be maintained, as the three specific characters insisted
upon by M. Agassiz, namely, the angular and truncated form of the posterior border,
the nearer approximation of the vent to the summit, and the possession of a very thick
test (‘‘ Le test est assez épais et recouvert d’une granulation assez uniforme sur toutes les
), were characters which did not hold good in the suite of specimens
collected. I therefore determined to describe it as a distinct species, associating. with
it a name most justly esteemed by all physiologists.

Clypeus Miillert has an oval form (fig. 2 a); rounded before, and slightly trun-
cated behind; the test is very thin, and on that account is not often well preserved,
the upper surface is flat and much depressed, it slopes more towards the posterior than
the anterior border ; the marginal fold is rounded, and the sides are tumid in proportion
to the height of the test (fig. 2 c).

The ambulacral areas are narrowly lanceolate, nearly of equal width, and closely
approximated around the disc ; the dorsal portions of the poriferous zones are widely petaloid,
each petal has an elegant leaf-like form, being narrow below, expanded in the middle, and
lanceolate above; for a short distance above the border, the pores forming a pair lie close
together (figs. 1 and 3), then gradually become wider apart, until they attain their maximum
separation in the middle of the dorsal surface; from this point they again gradually
approximate until they lie close together at the apex. The form of the ambulacral petals
(fig. 2 c) is one of the diagnostic characters of this species when compared with Clypeus
Plot ; in the latter the separation of the pores takes place much nearer the border than
in Clypeus Miilleri; they likewise taper more towards the apex, and form a much more
graceful figure on the upper surface of the shell than they do in that species.

IIx

parties intactes

® «fchinodermes Fossilles de la Suisse,’ prem. partie, p. 35.

re

FROM THE GREAT OOLITE. 373

The holes ‘of the inner row are round, those of the outer row in the form of
long slits (figs. 5 and 6); there is a narrow space external to the inner row (fig. 5),
beyond that the slit commences and passes transversely across the zones (fig. 6), where it
glides into the outer hole; one row of small granules occupies the space external to the
inner row of holes (fig. 6), and on the upper surface of the septa dividing the pairs
of pores a row of granules is disposed with great regularity (fig. 6); the ambulacral
plates are narrow above and broader below; on the upper surface there are seven pairs of
pores opposite one large inter-ambulacral plate, and at the base there are four pairs of
pores opposite one large plate. The basal portions of the poriferous zones are narrow,
and lie in shallow depressions of the surface; for about three fourths of the distance
between the border and mouth-opening, the pairs of pores are placed wide apart, at the
inner fourth they become more numerous and are disposed in close-set, triple, oblique
pairs, which form a penta-phylloid floscelle around the mouth (fig. 2 4, fig. 3 4).

The inter-ambulacral areas are of unequal width; the anterior pair are the narrowest
(fig. 2 a), the posterior pair the widest (fig. 2 a), and the single inter-ambulacrum about
the width of the latter; this area is slightly produced, deflected, and abruptly truncated
posteriorly.

The anal valley extends from the disc to the border; it is a narrow, lanceolate de-
pression, with vertical sides (fig. 2 a, fig. 1), which gradually expands from the apex to the
border; the vent opens at the extreme end of the valley beneath the disc, and the sides
of the channel bulge slightly outwards to give increased space to the intestinal aperture :
the base is nearly flat, and the inter-ambulacral segments form only inconsiderable eleva-
tions (fig. 2 4); the surface of the plates is covered with tolerably regular rows of very
small tubercles, encircled by microscopic granules, the fineness and minuteness of the
sculpture on the plates is therefore another character (fig. 5) by which it is distinguished
from Clypeus Plotii ; like other Clypei, the tubercles of the base are larger than those on
the dorsal surface.

The vertex is excentral and posterior (fig. 2 c), and immediately behind it is placed the
apical disc ; which is small and closely wedged in between the apices of the ambulacra ;
the disc is composed of two pairs of perforated genital plates, the posterior being larger
than the anterior pair; the large, spongy, madreporiform body occupies the center of
the disc, and extends as far as the ocular plates (fig. 4), which are small and scarcely visible
without the aid of a lens ; their minute marginal orbits are seen opposite the apices of the
ambulacra.

The mouth-opening is sub-central, nearer the anterior than the posterior border
(fig. 24); the peristome is surrounded by five small prominent lobes, formed by the
terminations of the inter-ambulacra; between the oral lobes the poriferous zones assume
a depressed, leaf-like figure, freely perforated in this region for the passage of
tubular organs, which, in this species, appear to have been very numerous around the

mouth.

374 CLYPHUS.

Afinities and differences.—Clypeus Muilleri more closely resembles Clypeus Plotii than
any other English species; having affinities with it in the form and structure of the
ambulacra, the extent and narrowness of the anal valley, and the depression of its dorsal
surface. It is distinguished from C. Ploti, however, by its oblong figure, truncated
posterior border, shorter and more graceful petaloidal ambulacra, finer and more minute
sculpture on the plates, a flatter base, with smaller tubercles thereon. The large specimen of
Clypeus Milleri (fig. 1) very much resembles Clypeus Michelini, but the widely petaloidal
character of the ambulacral areas in the former species present a great contrast to the
structure of the homologous portion of the test in the latter urchin, and serve to distinguish
them from each other; whilst the depression of the dorsal surface, the narrowness of
the anal valley, the smallness of the apical disc, and the microscopic sculpture on the
test, assimilate the two forms closely together.

It is distinguished from Clypeus Solodurinus, Ag., by having a much flatter under
surface, with inconsiderable undulations of the inter-ambulacra; whilst, according to
Agassiz, in the Swiss urchin, “ La face inférieure est réguliérement ondulée par suite de la
dépression des ambulacres.” The test in C. Miilleri is likewise extremely thin, the
sculpture fine, and almost microscopic; whilst in C. Solodurinus, “ Vie test est assez épais,
et recouvert d’une granulation assez uniforme sur toutes les parties intactes.”

Locality and Stratigraphical position.—I collected this Clypeus from the white
marly vein which traverses the upper region of the Great Oolite in some parts of
Gloucestershire, as near Cirencester, near Northleach, at Salperton tunnel, Great Western
Railway, near Minchinhampton, and near Cowley Wood; in all these localities it was
associated more or less abundantly with Zchinobrissus Woodwardi, Wr. Mr. Frederick
Bravender collected the fine large specimen figured in Pl. XX XIII, fig. 1, from the Forest
Marble near Cirencester. The Rev. A. W. Griesbach found one specimen in the Corn-
brash of Rushden, Northamptonshire, where it is extremely rare, as the specimen which
my kind friend has communicated is the only one he has seen in that locality.
M. Bouchard-Chantereaux sent me a specimen which he collected from the Great Oolite
near Boulogne-sur-Mer.

Lfistory.—This urchin was first discovered by Mr. 8. P. Woodward, in the Great
Oolite near Cirencester ; it was subsequently described in my memoir on the ‘ Cassidulidae
of the Oolites’ as Wucleolites Solodurinus, and is now figured for the first time as Clypeus
Millerr. I dedicate the species to the memory of Jéhannes Miiller, late Professor of
Physiology in the University of Berlin, whose profound observations on the anatomy,
physiology, and metamorphoses of the Echinodermata have thrown so much new and
important light on the natural history of this class of the Animal Kingdom.

FROM THE INFERIOR OOLITE. 375

Srction B. Anal valley does not extend from the border to the disc.
A. Species from the Inferior Oolite.
Cuirrreus Hueu, Agassiz. Pl. XXX, fig. 1 a, 4, ¢, d,e, f.

Ciypeus Hvueit. Agassiz, Echinodermes Foss. de la Suisse, 1° Partie, tab. x, fig.
2—4, p. 34, 1839.
_— — Agassiz and Desor, Cat. rais. des Ech. Ann. Sc. Nat., 3 série,
tom. vi, p. 156, 1847.
— _— D’Orbigny, Prod. de Pal. Strata, t. i. p. 290, No. 496, 1850.
Nucieouites Hvar. Forbes, Mem. of the Geol. Surv. of Great Britain, Decade 1,
description of Pl. ix, 1850.
—_ — Wright, Ann. and Mag. of Nat. Hist. 2d series, 1851, vol. ix,
p- 303.

— — Forbes, in Morris’s Catalogue of Brit. Fossils, p. 84, 1854.
Ciypropyeus Hvair. Desor, Synopsis des Echinides Fossiles, p- 274, 1857.
Ecurnoprissus Huei. Cotteau and Triger, Echinides du département de Ja Sarthe, pl. vi,

fig. 10—12, p. 58, 1858.

Test sub-orbicular, dorsal surface convex; apical disc central; ambulacral areas
narrowly petaloid in the upper two thirds of the dorsal surface ; anal valley short, and
wide, occupying the lower half of the area; a considerable portion of undepressed test
between the disc and valley, single inter-ambulacrum produced and deflected; base
nearly flat, mouth-opening sub-central, nearer the anterior than the posterior border,
peristome pentagonal, surrounded by five oral lobes; a penta-phylloid floscule around the
mouth.

Dimensions.—Height, one inch; length and breadth nearly equal, two inches and
one eighth.

Description —All the specimens of this urchin I examined before the fine example
figured in Pl. XXX, were small, and resembled Achinodrissus, but in this urchin the
characters of Clypeus are well marked ; the test is circular, being nearly as long as it is
broad ; it is rounded before (fig. 1 a), and slightly rostrated behind, by the prominence
and deflection of the single inter-ambulacrum (fig. 1 4); the upper surface is uniformly
convex (fig. 1 c), in the figured specimen it is rather conical, rising high at the vertex,
and declining rapidly on all sides, more especially towards the posterior border ;
the base is flat or slightly concave, and the basal portions of the inter-ambulacra form

AQ

376 CLYPEUS

prominent undulations between the narrow ambulacra (fig. 1 6, ¢). The ambulacral
areas are narrowly lanceolate, the anterior pair curve gently upwards and outwards, and the
posterior pair upwards and inwards; the poriferous zones are narrowly petaloid three
fourths of their length between the border and disc; at the lower fourth the pores forming
a pair are closely approximated, and the rows are very narrow; above this point the pores
of the inner row are round, those of the outer row in the form of oblong slits
(fig. 1 e), which are connected with the inner row by fine sutures ; the transverse sulci dis-
appear some distance above the border, the pores then become simple, oblique, and wider
apart ; in the basal portion of the zones the pores are minute and far apart, and their
track is only traced by the depression formed by the ambulacra near the mouth-opening ;
around the peristome (fig. 1 4) the pores become more numerous, and form five leaf-like
expansions. ‘The inter-ambulacral areas are of unequal width, the anterior pair are the
narrowest, the single area the widest, and the posterior pair of unequal dimensions (fig. 1 a);
the anterior border is obtusely rounded, the sides swell gradually outwards to the junction
of the posterior pair with the single area, the widest part of the test is in the direction of a
line passing transversely across the vertex ; the single inter-ambulacrum is slightly produced,
deflected, and truncated (fig. 1 a, d); the anal valley is short and wide, and occupies the
lower half of the inter-ambulacrum (fig. 1 a, c,d); between the upper portion of the
valley-arch and disc the test is undepressed (fig. 1 a); the vent occupies the extreme
termination of the valley, and its perpendicular sides are scooped out (fig. 1 d) to afford
greater space for the passage of the intestinal tube and the closure of the aperture by its
circle of anal plates (Pl. XLI, fig. 1).

The apical disc is small, and its elements so intimately soldered together that their
separate study is impossible in the specimen figured ; the disc, moreover, is so much
covered over by the madreporiform body that the sutures are all concealed (fig. 1 f). In
another small specimen the disc is composed of two anterior and two posterior perforated
ovarial plates, and a single imperforate ovarial; the five ocular plates are very small
and their orbits marginal.

The test is moderately thick, and the surface of the plates is covered with several
horizontal rows of small tubercles (fig. 1 e); the base of each is encircled by a sunken
areola, and the intermediate portion delicately sculptured with microscopic granules
(fig. 1 e); the tubercles at the base are only a little larger than those on the upper surface.

The base is flat, slightly concave, or undulated, the ambulacra form straight
valleys, and the inter-ambulacra moderately convex elevations; the prominence of these
undulations and the deflection of the inter-ambulacrum are greater in proportion in small
individuals. The mouth-opening is excentral, being situated near the junction of the
anterior with the middle third of the antero-posterior basal diameter; the pentagonal
peristome is surrounded by five lobes, and the terminations of the ambulacra form five

Jeaf-like expansions, or a penta-pbylloid floscule in which the pores are arranged in triple
oblique ranks,

FROM THE INFERIOR OOLITE. 377

Afinities and differences.—The general outline of some of the smaller specimens of this
urchin resembles “chinobrissus orbicularis, but the structure of the ambulacra, and of
the apical disc, the size and position of the anal valley, together with the undepressed
portion of test between the apex of the valley and disc, readily distinguish it. The
larger form (fig. 1 a) differs so entirely from other Clypei that it cannot be mistaken
for any of its congeners, whilst its orbicular outline, petaloidal ambulacra, small
solidified apical disc, and mouth-opening provided with oral lobes, justify its position
among the Clypei rather than with Aehinobrissus, among which I formerly placed it.

Locality and Stratigraphical position.—I have collected Clypeus Hugit in the Lower
Trigonia Grit, zone of Ammonites Parkinsoni Inferior Oolite; at Rodborough Hill,
Shurdington Hill, Leckhampton Hill, and Ravensgate Hill; the large figured specimen
was found at Shurdington Hill. I have collected many specimens from the Trigonia
Grit at Hampen ; many years ago it was found in considerable abundance in the upper
ragstones of the Inferior Oolite with Zrzgonia costata at Charlcombe, near Bath. The
Hampen specimens are associated with Pedina rotata, Wr., Hyboclypus ovalis, Wr.,
Holectypus depressus, Lamk., and Clypeus Plotii, KI., with several species of Conchifera
characteristic of that zone of life, as Zirigonia costata, Sow., Pecten symmetricus, Mor.,
Tancredia donaciformis, Lyc., and Quenstedtia oblita, Phil., together with Anthozoa, as
Anabacia orbulites, Lamx.

The foreign distribution of Clypeus Hugii, is, according to M. Desor, “ Marnes a
Discoides (Vesulien), de Hornussen et de Bozen (Argovie), des environs d’Olten, du Mont
Terrible.”

In Switzerland, he adds, this species is the faithful companion of Holectypus depressus,
Collyrites ovalis, and Hchinobrissus clunicularis, and one of the most characteristic
fossils of the Marnes a Discoides, the zone of Ammonites Parkinsoni Inferior Oolite, so
that its statigraphical position and paleontological associates is the same in the Alpine
regions of Switzerland, as in the Cotteswold Hills.

The true zone of this species in the department of the Sarthe is yet uncertain, the
only specimen found was collected near Mamers. I have no doubt its bed will be found to
be the Inferior Oolite.

378 CLYPEUS

Curyprus Acassizu1, Wright. Pl. XXXI and XXXII.

Nucizouites Acassizi1. Wright, Ann. and Mag. of Nat. Hist., 2d series, vol. ix, p. 308,
Pl. iu, fig. 3 a—e, 1851.
— ~ Forbes, in Morris’s Catalogue of Brit. Foss., 2d ed. p. 84, 1854.
CLyPEUS AGASSIZII. Desor, Synopsis des Echinides Fossiles, p- 278, 1857.
— — Davoust. Note sur les Fossiles spéciaux 4 la Sarthe, p. 25, 1856.
— — Cotteau and Triger, Echinides du département de la Sarthe, pp.
16 and 61, pl. iui, fig. 1; pl. ix, fig. 9; pl. ix, fig. 1—3.

Test large, hemispherical, or sub-conoidal ; margin sub-circular ; a little longer in the
antero-posterior diameter; rounded before, slightly rostrated, and truncated behind;
vertex central, apical disc excentral, and inclined backwards; ambulacral areas very
narrow ; poriferous zones widely petaloid and conjugate from above the margin to the disc ;
at the margin and base, pores simple, non-conjugate, and scarcely visible ; near the mouth
more numerous and apparent, and arranged in triple oblique pairs; vent oblong, and
near the surface; anal valley very shallow, commencing in the middle of the single
inter-ambulacrum ; an undepressed portion of test between the vent and disc, sometimes
sulcated in the middle; base flat, or slightly undulated ; mouth-opening large, subcentral ;
peristome surrounded by five prominent lobes; dorsal tubercles nearly microscopic ; basal,
a little more conspicuous.

Dimensions.—Height, two inches and one quarter; antero-posterior diameter, four
inches and one fifth ; transverse diameter, four inches.

Description.—The large size, the hemispherical or sub-conoidal form of the upper
surface, the flat base, and superficial anal valley, readily distinguish this magnificent species
from all other Clypei. ‘The outline of the margin is nearly circular, the antero-posterior
being a little more than the transverse diameter ; the test is rounded before, and slightly
rostrated, and truncated behind ; the upper surface assumes a conoidal figure (Pl. XXXII,
fig. 1, a); the vertex is central, and the test declines more towards the posterior than the
anterior border.

The ambulacra are long, narrow, and lanceolate; the anterior area is straight; the
antero-lateral pair describe an /shaped curve on the sides of the test (Pl. XXXII, fig.
1, a); and the postero-lateral curve forwards upwards and inwards at the posterior surface
(Pl. XXXII, fig. 1, 3).

The poriferous zones are very large, and widely petaloid on the upper surface (PI.
XXXI, fig. 1, a); they are formed of an inner row of small, simple, round, or oval pores,
which extend equidistant from the margin to the disc, and an external row, of long,

FROM THE INFERIOR OOLITE. 379

narrow, transverse pores, connected with the inner row by conjugate sulci; the septa
between the transverse pores support, on their upper surface, a regular row of small
tubercles (Pl. XXXII, fig. 1, c). Near the marginal fold the pores of the outer row
are round, like those of the inner row, and form narrow zones of close-set pores, only
apparent by faint depressed lines, which mark the track of the zones from the border
to the mouth; near the peristome the pores become more numerous, and here forma
series of triple oblique rows of pairs. Pl. XXXII, fig. 1, d, represents one of the basal
ambulacral areas, highly magnified (Pl. XX XI, fig. 1, 4).

The inter-ambulacral areas are of unequal width at the margin; the anterior pair are
the narrowest, the posterior pair are wider, and the single area is the widest; they are
uniformly convex on the upper surface, and are formed of very large pentagonal plates,
bent in the middle ; each plate supports four horizontal rows of small tubercles, surrounded
by sunken areolas, and having the inter-tubercular surface covered with fine, microscopic,
homogeneous granules. Pl. XXXII, fig. 1 ¢, exhibits the ambulacral plates, poriferous
zones, and two inter-ambulacral plates magnified three diameters, and shows that there are
seven pairs of pores opposite each large plate.

The under surface is flat, and the basal portions of the inter-ambulacra are only slightly
cushioned ; the tubercles in this region are larger, and not so regularly arranged in rows
as on the upper surface (PI. XXXI, fig. 1 4), but are scattered more promiscuously over the
surface.

The height of the test, and the excentral position of the apical disc, inclined backwards
behind the vertex, occasions the curvature in the lateral ambulacra already described
(Pl. XXXII, fig. 1a). The disc is small, in proportion to the size of the test (PI.
XXXtI, fig. 1 a), and is composed of two anterior, and two posterior perforated ovarial
plates, and a single imperforate plate. The madreporiform body covers all the centre of
the disc, and the five ocular plates are only indicated by their marginal orbits at the apices
of the ambulacra; the elements of the disc are closely soldered together, and only
occasionally seen distinct in some decomposed specimens.

The dorsal portion of the single inter-ambulacrum, when viewed posteriorly (P]. XXXII,
' fig. 1 4), presents a triangular figure; the border forms the base, and the two postero-
lateral-ambulacra the sides of the triangle; near the middle of this space is placed the
oval vent, which opened near the surface (fig. 1 4); the anal valley, is a very shallow
depression, from its sides, two nodulated ridges descend downwards and outwards
towards the border, the plane of the intermediate space being a little beneath the general
plane of the test (fig. 1 4). In some smaller specimens there is sometimes a
narrow depression which passes upwards from the summit of the arch above the anal
valley towards the disc, which is effaced in the large type specimen (fig. 1 4);
in this urchin the space between the upper border of the opening and the disc is occupied
to the extent of one inch by a smooth, slightly depressed portion of test ; which, added
to the oval vent, shallow valley, and superficial depression beneath, form a group of

380 CLYPEUS

characters which well characterise this noble urchin ; in the fine large specimen figured by
my friend M. Cotteau from the Inferior Oolite of the Sarthe, a narrow sulcus extends
from the disc to the summit of the anal arch.

The mouth-opening is large and sub-central (Pl. XX XI, fig. 1 4); it has a pentagonal
form, and the peristome is surrounded by five large, prominent, oral lobes, formed by the
terminal folds of the inter-ambulacra; alternating with the lobes, the five ambulacra
form a depressed penta-phylloid floscule around the mouth opening, which imparts a
marked stellate character to the flat base of this Clypeus.

Affinities and differences.—This fine species is distinguished from its congeners by its
elevated, sub-conoidal, dorsal surface, its flat base, its excentral apical disc, declining
towards the posterior border, its short, shallow, anal valley, and oblong vent. In some
specimens the anal valley is more developed than in our large fine type urchin; this is
apparent in two other individuals I possess, and M. Cotteau has made the same remark
on some of the specimens which he has examined from the Sarthe: ‘‘ Suivant, M. Wright,
cette ouverture est a fleur du test, presque superficielle (nearly superficial). Ce caractére
n’existe pas toujours, et dans plusieurs de nos exemplaires, notamment dans celui que
nous avons fait représenter, l’anus s’ouvre dans un sillon aigu, au milieu d’une depression
trés-apparente de l’inter-ambulacre-postérieur ; mais cette différence ne nous a pas empéché
de le réunir au Clypeus Agassiz. Les échantillons d’Angleterre présentent eux-mémes
quelques traces de sillon et appartiennent certamement au méme type que les ndtres.” *

Locality and Stratigraphical position.—This urchin has hitherto been found only in the
upper ragstones of the Inferior Oolite, near Bridport, in the zone of Ammonites
Parkinsoni, at Barton-Bradstock, and Walditch Hill; its associates in the same bed are
Clypeus altus, M‘Coy; Holectypus hemisphericus, Desor; MStomechinus bigranularis,
Lamk.; Collyrites ringens, Desml.; Collyrites ovalis, Leske; Hyboclypus gibberulus, Ag. ;
Ammonites Parkinsom, Sow.; Ammonites subradiatus, Sow.; Trigonia costata, Sow.

History.—First figured and described in my memoir on the Cassidulide of the Oolites
‘Ann. and Mag. of Nat. Hist.’, for 1851. It has recently been beautifully figured and
well described by MM. Cotteau and Triger, in their fine monograph ‘ on the Echinides’ of
department of the Sarthe.

* Cotteau and Triger, Echinides du département de la Sarthe, p. 17, 1858.

FROM THE INFERIOR OOLITE. 3381

CLYPEUS RIMOSUS, Agassiz.

/
CLYPEUS RIMOSUS. Agassiz and Desor, Catalogue raisonné des Echinides des Sciences
Naturalles, 3° serie, tome vii, p. 156.
4
_ — Desor, Synopsis HEchinides Fossiles, p. 277.

This urchin was entered in the catalogue raisonné as, “ Espece plate, discoide, a
ambulacres costulés, Terr., Jurass. du Gloucestershire, Deluc ;’ in the ‘Synopsis des
Hchinides Fossiles,’ M. Desor gave the following detailed diagnosis of it: ‘ Species dis-
coidal, slightly convex, subrostrated posteriorly ; ambulacral summit central; anal valley
very narrow, extending to the apical disc ; ambulacral petals convex and prominent, with
very large poriferous zones, which equal im width the inter-poriferous spaces; base
undulated, peristome excentrally forwards; the pores disposed in double ranks in the
phyllodes ; oral lobes small and not approximated.” M. Desor, in a note, adds, “ by its
general form, as well as by its costulated petals, this species approaches much to C.
Michelin, Wr., but the poriferous zones, instead of being distinguished by their
narrowness, are remarkable for their breadth. Should it happen to be demonstrated by a
series of examples that this character is not constant, it would be possible to unite these
two species.”

After a careful examination of all our Oolitic Clypei, with the view to identify M.
Deluc’s specimen, which was said to have been collected from the Inferior Oolite of
Gloucestershire, I have been unsuccessful.

Long before the publication of M. Desor’s Synopsis, it occurred to me that C. rimosus
might be a variety of C. MWichelini, one character, however, pointed out in the diagnosis,
“ poriferous zones very large, equalling the inter-poriferous space,” is sufficient to prove
that this is not the case, seeing that C. Michelini is as remarkable for the narrowness of the
petaloid portion of the poriferous zones, as C. rimosus is for their breadth, and this
character is constant in the large series of specimens I have examined. The breadth of
the poriferous zones establishes an affinity with C. Afilleri, but in that species the test is
oval, the ambulacra are on the same plane with the inter-ambulacra and not costulated as
in C. rimosus. It is probable that this urchin may prove to be a depressed variety of
C. Ploti.

382 CLYPEUS

CLyPEus suBuLATUS, Young and Bird. Pl. XXXIV, fig. 1 a, 6, ¢, d, e, f, g.

ECHINITES SUBULATUS. Young and Bird, Geol. Surv. of the Yorkshire Coast, pl. vi,
fig. 11, p. 214, 1827.
CLYPEUS EMARGINATUS. Phillips, Geology of Yorkshire, pl. iui, fig. 18, p. 127, 1829.

— — Morris’s Catalogue of British Fossils, p. 50, 1843.
NUCLEOLITES EMARGINATUS. Forbes, Memoirs of the Geological Survey, Decade 1,
descrip. pl. i.
— — Wright, Ann. and Mag. of Nat. Hist., 2d ser. vol. ix, p. 310,
1851.
PYGURUS EMARGINATUS. Desor, Synopses des Echinides Fossiles, p. 316, 1857.

Test large, oblong, and much depressed; sides equally declining ; vertex and apical
disc nearly central; ambulacra narrowly lanceolate; poriferous zones petalloid, on the
upper three fourths of the dorsal surface; simple, in the lower fourth; anal valley
short and deep, far removed from the disc, and occupying the lower third of the area;
anterior border rounded ; posterior border produced, rostrated, and deflected ; base con-
cave ; mouth subcentral ; basal inter-ambulacra much cushioned ; margin gently undulated ;
tubercles small, and disposed in rows.

Dimensions.—large specimen, fig. 1 a, 6. Height, one inch; antero-posterior
diameter, three inches and four tenths ; transverse diameter, three inches and one fifth.
Smaller specimen, fig. 1 c, d. Height, nine tenths of an inch; antero-posterior diameter,
two inches and six tenths ; transverse diameter, two inches and six tenths.

Description.—This beautiful Clypeus has hitherto been found only in the Coralline
Oolite of Yorkshire, and was first described from that formation by the Rev. George
Young, in his ‘ Survey of the Yorkshire Coast.’ The figure given in that work is very bad,
but the description is sufficiently accurate to identify the species: “‘The dorsal surface
has the same elegant markings as No. 5 (Pygurus pentagonalis), but the petals are rather
awl-shaped than lanceolate, from which peculiarity we name it Yehinites subulatus. The
middle part of each petal forms a slight ridge; on the contrary the five corresponding
marks on the base, meeting in the mouth, are depressed. The base is concave, and the
mouth is situated immediately under the vertex. The vent is im a short groove on the
edge, but more towards the upper surface, as in some of the Spatangus family.”*

When I published my memoir on the Cassidulidee of the Oolites + I could not obtain a
specimen of this urchin; most of those contained in the Yorkshire collections are either

* Geological Survey of the Yorkshire Coast, 2d ed. p. 214.
+ Annals and Magazine of Natural History, 2d series, vol. ix, p. 310, 1851.

FROM THE CORALLINE OOLITE. 383

crushed or have been much injured in cleaning; fortunately I have obtained two
good examples, which have been beautifully figured in Pl. XXXIV, one of these
specimens was obtained from a band of clay and has the form and sculpture finely
preserved.

The thin test has an oblong form, rounded before, dilated in the middle, and
a little rostrated behind (fig. 1 a); the upper surface is uniformly convex (fig. 1 ¢) ;
the sides decline equally towards the border (fig. 1 ¢), which is rather attenuated; when
the shell is viewed in profile, the margin is seen to be much undulated (fig. 1 ¢, d).

The ambulacral areas taper gradually from the border to the disc (fig. 1 a), and lie on
the same plane with the general surface of the test ; the poriferous zones on the dorsal
surface are petalloid for three fourths of the space between the border and disc, they lie
rather beneath the general plane of the test, and form very uniform graceful petals on the
upper surface, narrow below, gradually swelling out in the middle, and tapering to narrow
lanceolate terminations at the disc (fig. 1 a); the pores of the inner row are round (fig. 1
e), those of the outer row in the form of long, narrow, transverse slits; the pores of
both rows are conjugate through fine sulci; there are eight pairs of pores opposite
one of the large plates, and a septum between each transverse slit, the outer surface
of which supports a regular row of fine granules (fig. 1 e).

At the lower fourth of the areas the pores le close together, the rows are here very
narrow, and continue so across the base, the pairs of pores in this region, being placed at
wider distances apart (fig. 1 4), near the mouth-opening they lie closer together in triple
oblique rows in the penta-phylloid floscelles of the ambulacra, which radiate outwards
between the lobes in depressions of the test (fig 1 4).

The inter-ambulacral areas are of unequal width; the antero-lateral pair are the
narrowest, and the postero-lateral pair, and single area, are of the same width, but broader
than the anterior pair; thew surface is marked by two slight ridges, which radiate from
the disc to the border, and subdivide each area into three segments. In specimens which
have been scraped or filed, unfortunately almost universally the case with this Clypeus,
these ridges are not seen; but in the small, nearly perfect specimen (fig. 1 c, d), they form
avery prominent character inits upper surface, and which is faintly represented in fig. 1 a
in the left antero-lateral segment. The inter-ambulacral ridges form distinct prominences
at the border, and on the surface of the basal cushions; they likewise form two
small carinee on the deflected basal surface of the small specimen (fig. 1d¢). The small
tubercles are arranged in rows with great regularity on the plates, of these there are in
general four on each; the tubercles are surrounded by sunken areolas, and the inter-
mediate surface is covered with rather large granules (fig. 1 7), which give a highly
ornamented sculptured surface to the test, when examined with an inch lens. The
tubercles at the base are very much larger than those on the upper surface; some of them
likewise are perforated, especially those situated in the concave depression in the vicinity

of the mouth (fig. 1 /).
50

334 CLYPEUS

The single inter-ambulacrum forms one of the most remarkable features in the
anatomy of the test; the anal valley is short, deep, and limited to the lower third
of the dorsal portion of this area (fig. 1 @); the posterior part of this segment is
rostrated, and much deflected (fig. 1d), and its extremity abruptly truncated (fig. 1 a, d) ;
the arch over the vent is narrow above, its sides slope a little inwards, and the opening
expands towards the border (fig. 1, a, 7) ; the vent opens near the surface beneath the
arch (fig. 1 d); it has an oval form with tts long diameter towards the vertex.

The base is concave (fig. 1 4), and the iter-ambulacra form prominent cushions
between the narrow ambulacra, the convexity of these segments produces a considerable
undulation in the border, which is well represented in fig. 1 c, d; the mouth-opening is
sub-central, nearer the anterior than the posterior border, it has a pentagonal form, and
the peristome is surrounded by five prominent oral lobes (fig. 1 4).

The apical disc is very small, it occupies the centre of the upper surface, and forms
the vertex of the test; I have only seen one specimen in which this part is preserved.
‘The separate plates are so intimately soldered together, that I can only recognise the four
genital holes which perforate the test obliquely (fig. 1 g), and the five ocular holes at the
summits of the ambulacra; the surface of the discal plates is covered by a spongy
madreporiform body which forms the most conspicuous element in the small central disc

(fig. 1 g).

Affinities and differences.—Clypeus subulatus is frequently mistaken for Pygurus
pentagonalis, Phil., and lies with this name attached, in several Yorkshire collections. In
fact, the oblong figure of the test, the apparent absence of an anal valley, which is always
filled up with matrix, and seldom cleared out, the form of the ambulacral petals, and the
central position of the small apical disc, produce an assemblage of characters which have
misled local observers. M. Desor, in his synopsis, has placed this Clypeus in the genus
Pygurus, and has added this note to his diagnosis—‘“ Cette position exceptionnelle du
périprocte n’est pas une raison suffisante pour éloigner cette espece au Pygurus auxquels
elle correspond par tours ses autres caractéres.” I can readily understand how this
mistake has been committed, if M. Desor’s opinion was formed from Phillips’s figure,
the only one up to the present time worthy of the name of a sketch which has been
published. 1 trust, however, that Mr. Bones’s beautiful plate, with its ample details
will set the question at rest, for there can be no doubt that this urchin is a
true Clypeus. It has no affinity with any other English congener; its concave under
surface, and strongly-cushioned basal inter-ambulacra, resemble the base of Clypeus
altus ; but that species has an orbicular outline, and a long, narrow, anal valley, which
widely separate it from Clypeus subulatus. \t more nearly resembles Clypeus Rathieri,
Cott., from the Forest marble of Chatel-Gérard (Yonne), than any other species ; but the
narrowness of the anterior border, the flatness of the base, and the excentral position of
the disc, prove how specifically distinct they are from each other. I may add, that the

FROM THE CORALLINE OOLITE. 385

small specimen from the clay band (fig. 1), is the only example I have yet seen which
shows the basal surface, now published in fig. 1 4, for the first time.

Locality and Stratigraphical position.—This urchin has hitherto been collected only from
the Coralline Oolite cf Malton and Scarborough, although I have seen fragments of it im the
Ayton quarries. It is usually imbedded in a white Oolitic limestone, firmly attached by the
base in consequence of its inequalities, and, having the upper surface exposed, the matrix
is usually removed by scraping; but the Oolitic grains frequently indent the surface of the
plates. ‘This species was formerly more abundant, than now, probably because the vein
containing the fossil was worked more in former years. Almost all the specimens are
fractured and crushed, and it is rare to find one which preserves the true type-form of the
species. For the same reason we seldom observe the ridges which radiate from the
disc to the mouth-opening, on the surface of each inter-ambulacral segment. I have
never seen them distinctly, but in the two specimens I have figured, where they un-
doubtedly exist, and form a good diagnostic character for the species.

History.—It was first figured and described as Echinites subulatus, by Young and
Bird, in their ‘ Geological Survey of the Yorkshire Coast,’ and afterwards by Professor
Phillips, as Clypeus emarginatus, in bis ‘ Geology of Yorkshire; the first name must
therefore be retained. Professor Forbes gave a diagnosis of the species in his ‘ Notes on
British Oolitic Nucleolites,’ im the first decade of his ‘Memoirs of the Geological
Survey.’ It was imperfectly described, for want of specimens, in my ‘ Memoir on the
Cassidulidee of the Oolites ;’ but is now figured, with full details, from two fine speci-
mens, for the first time.

386

NOTES

On ForEIGN JURASSIC SPECIES OF THE GENUS CLYPEUS NEARLY ALLIED TO Bririsu
FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OoLiTEs.

CLYPEUS SOLODURINUS, Agassiz. Syn. Echinoderm, Foss, Suisse I, p. 35, tab. v,
figs. 1—3.

Test very thick, narrow, and elongated, posterior border angular, produced, and
truncated ; ambulacra narrow, poriferous zones petaloidal, contracted at the lower fourth,
apical disc central ; anal valley lanceolate ; vent in its upper part, near the apical disc,
which is small and nearly central; border undulated, base nearly flat, with prominent
inter-ambulacral cushions ; mouth-opening large, peristome surrounded by five lobes.

Dimensions.—Antero-posterior diameter, two inches and nine tenths; transverse
diameter, two inches and eight tenths; height, eight tenths of an
inch.

Formation.—“ Oolite Vesulienne, d’Obergoesschen (Jura Soleurois) , Ege (Argovie) ;
Plasne pres Poligny (Jura) .” Desor.

Collections —MM. Strohmeyer, Bronn, Marcou.

Cuypzus Bosuay1, Michelin. Cotteau and Triger. Hchinides du depart. de la Sarthe,
pl. xi, figs. 4, 5; p. 64.

Test moderate size, sub-circular, round before, slightly truncated behind; dorsal
surface much depressed, almost flat; under surface sub-concave. Summit very excen-
trical posteriorly ; anterior ambulacral areas much longer than the posterior. Poriferous
zones widely petaloid on the upper surface, and becoming abruptly contracted near the
border, where the pores are simple and non-conjugate; anal valley narrowly lanceolate,
and becoming regularly wider from the disc to the border.

Dimensions. —Height, three quarters of an inch; antero-posterior diameter, three

inches and nine tenths; transverse diameter, four inches and one
tenth.

FOREIGN JURASSIC CLYPEI. 387
Formation.—Great Oolite, near Mamers Sarthe.

Collection.—M. Michelin ; very rare.

Cryrrus Rarutieri, Cofteau. Echinides Foss., de l’Yonne, pli vi; paytle

Test elongated, very flat on the dorsal surface, and concave at the base; anterior
border rounded, and sub-truncated; posterior half of the test much wider and
thicker ; posterior border rostrated. Ambulacral areas widely petaloid in the middle of
the dorsal surface, narrowly lanceolate near the disc, and contracted near the border;
anal valley short, narrow, and marginal; occupying the lower third of the inter-ambu-
lacrum, and forming a groove in the posterior border ; mouth-opening small, sub-central ;
peristome surrounded by five lobes.

Dimensions.—Height, six tenths of an inch; antero-posterior diameter, two inches
and a half; transverse diameter, two inches and a quarter.

Formation.—Siliceous beds of the Forest marble (Great Oolite) at Chatel-Gérard,
Yonne.

Collection.—M. Rathier ; very rare.

Cuyprus OsrerwaLp1, Desor. Synopsis des Echinides Foss. p. 277.

Test large, depressed, enlarged, and rostrated posteriorly ; anal valley very narrow,
extending to the apical disc, which is central. Poriferous zones, in width about one half
the ambulacral area; base, much undulated ; mouth-opening excentral; peristome, with
five lobes and a penta-phylloid rosette, in which additional pores are arranged in double and
triple oblique ranks.

Formation.— Great Oolite (Bathonien) de Noiraigue (Canton de Neuchatel) au
dessous des marnes 4 Discoidées. Abondant.’’ Desor.

Collections. —M. Gresley, Mus. de Neuchatel.

CiypEus RosTratus, Desor. Synopsis des Echinides Foss. p- 278.

Test elevated, sub-conical; posterior border much rostrated ; anal valley very much

388 FOREIGN JURASSIC CLYPEI.

inclined, and almost vertical; ambulacral petals less elongated than in the preceding
species ; base concave, much undulated; mouth-opening excentral ; peristome with three
small lobes. ‘Type of the species, 'I’. 4.

Formation.— Marnes a Discoidees (Vesulien) du Kornberg prés Frick et de Hornussen

Argovie).” Desor.
to}

Collections—Mus. Bale, MM. Moesch, Schmidlin.

389

Family 10. ECHINOLAMPIDA, Wright, 1855.

Nuc.eourp£Es (pars), dlbin Gras., 1848.
EcHINOBRISSID& (pars), D’ Orbigny, 1855.
ECHINOLAMPASID# (pars), Grey, 1855.
CassIDULIDEs (pars), Desor, 1858.

The family Ecuinozamprp includes all the urchins which have petaloid or sub-
petaloid ambulacra ; the vent, supra-marginal, marginal, or infra-marginal, opening at the
surface of the test, and not into an anal valley; the mouth edentulous; the peristome
surrounded by five oral lobes, with which petaloidal expansions of the basal ambulacra
alternate ;

The thin test has in general an oval, oblong, sub-pentagonal, or orbicular form, the
upper surface is convex, and depressed, elevated, or conoidal; the vertex is usually excen-
tral, and situated nearer the anterior border.

The ambulacral areas and poriferous zones form elegant leaf-like expansions on the
dorsal surface, and miniature petals at the base, where they develope an “oral rosette,”
or a penta-phylloid floscelle around the mouth; the leaves alternate with the prominent
peristomal lobes, in which the pores are arranged in crowded oblique ranks.

The small apical disc is composed of a single imperforate, and four small perforated
ovarial plates ; the madreporiform body is proportionally large, extending over the other
discal elements ; the five ocular plates are very small, with marginal orbits.

The vent always opens at the surface of the test, and never into a valley, as in the
Ecatnosrissip&. The opening has an oblong form; its long diameter corresponding
with the transverse diameter of the test in some genera, and with the longitudinal axis in
others; it occupies a marginal, supra-marginal, or infra-marginal position. In some
existing species this aperture is closed by three thin, shelly valves, covered with tubercles ;
the lateral valves are larger and triangular, the central one linear, erect.*

The tubercles are often perforated, and surrounded by sunken areolas ; in Hehinolampas
and Pygurus, the inter-tubercular surface is covered with a close set granulation, and the
tubercles at the base are much larger than those on the upper surface.

The EcutnoLampip#& form a natural group, nearly equivalent to the Zchinanthi, of
Breynius,f and which that author thus defined :

“Hcwinantuus est Echinus cujus apertura pro ore est prope centrum, pro ano in, vel
ad marginen, longissime ab ore distantem.”

Figuram omnes hujus species habent ovalem, cujus altera extremitas angustior, altera
latior, in qua semper apertura pro ano observatur. Ceterum pori in vertice schema
efformant floris cujusdam penta-petali, quasi acu artificiose delineatum; et hee ratio
est cur huic Generi Hchinanthi nomen imposuerin.

* ©Gray’s Catalogue of the Recent Echinida of the British Museum,’ p. 35, 1855.
+ ‘De Echinus et Echinites,’ p. 59.

390 ECHINOLAMPID &.

This definition unfortunately embraces forms which appertain to several genera.
Even the three species figured as Hehinanthus, in Tab. iv, of Breynius’s work, from the
position of the vent, represent two. distinct types.

The EcuinoLampip#z resemble the Ecutnoprissip# in the general organization of
their test ; but the species are distinguished from those of that group by the position of
the vent, the development of the peristomal lobes, the basal ambulacral rosette, and by the
tubercles, in some genera at least, being perforated.

In the following table I have given a short diagnosis of the genera, and include in the
family EcuinoLaMpip&, together with their stratigraphical distribution in time.

A TABLE SHOWING THE CLASSIFICATION AND DISTRIBUTION OF THE ECHINOLAMPIDZ.

FAMILY. DraGnosis. GENERA. FoRMATION.

Test, oblong, inflated ; petals long, narrow,

nearly reaching the border; vent trans. p PYGORHYNcHUs, Agassiz. Tertiary.

verse, supra-marginal.
Test oblong, depressed ; petals short, nar-

row, limited to the dorsum; vent oval, Ecuinantuus, Breynius. Tertiary and Upper Creta-

ceous.
marginal, or supra-marginal.
Test ovoid or discoid; petals wide, long,
nearly reaching the border ; vent, trans- ¢ EcHINoLAMPas, Grey. Living and Tertiary.
verse, infra-marginal.
Henge, eng, aEUnINS Ne Wash ven Pyeurus, Agassiz. Cretaceous and Oolitic.

infra-marginal, longitudinal, surrounded
by a distinct area.
Test oblong, depressed; petals long, nar-

row, reaching the border; vent longitu- | Borriopycus, D'Orbigny. Cretaceous.

ECHINOLAMPIDA.

dinal, marginal.
Test elevated, or conical; petals narrow,
lanceolate, short, limited to the dorsum ;

7 ) Fausasia, D’ Orbigny. Upper Cretaceous.
vent small, transverse, without area; base
flat, without elevation.
Test large, oval or circular, much elevated,
or conoidal ; petals long, straight, wide, CoNOCLYPUS, Agassiz. Tertiary and Cretaceous.

equal, not contracted below ; vent infra.

Test large, discoidal, or elevated ; es

KL marginal, triangular ; base flat.

PALAONTOGRAPHICAL SOCLETY.

INSTITUTED MDCCCXLVII.

ISSUED FOR 1858.

LONDON :

MDCCCLX.

A MONOGRAPH

ON THE

Dat Prish FOSSIL

ECHINODERMATA

FROM

THE OOLITIC FORMATIONS.

BY

THOMAS WRIGHT, M.D., F.R.S.E. F.G.S.

CORRESPONDING MEMBER OF THE ROYAL SOCIETY OF SCIENCES OF LIEGE,
AND SURGEON TO THE CHELTENHAM HOSPITAL.

PART FOURTH,
CONTAINING

THE ECHINOLAMPIDA,
THE STRATIGRAPHICAL DISTRIBUTION OF THE OOLITIC SPECIES,
THE BIBLIOGRAPHY OF THE ECHINODERMATA, AND
ADDITIONAL NOTES ON THE ECHINOIDEA.

LONDON:
PRINTED FOR THE PALAONTOGRAPHICAL SOCIETY. xX!
1860.

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391

Genus—PYGURUS, d@’ Orbigany, 1855.

EcutnantuitEs, Leske, 1778.
CLYPEASTER (pars), Lamarck, 1801.
EcurnoLaMPas (pars), Agassiz, 1836.
Pycurus (pars), dgassiz 1840.
PycGurus, @’ Orbigny, 1855.
PyGuRus, Desor, 1858.

The genus Pygurus, as now limited, is composed of large, discoidal, or clypeiform
urchins, in which the test in general is more or less enlarged at the sides, and rostrated
posteriorly ; its upper surface is usually depressed, and rarely elevated.

The ambulacral areas and poriferous zones in the upper surface form petaloidal expan-
sions, which have an elegant form, being in general contracted at the border, enlarged
in the middle, and attenuated at the apex. ‘The anterior single area is narrower than the
antero- and postero-lateral areas; the summit is in general central, or slightly excentvral,
the inclination being always forwards.

The base is concave and much undulated, the wide basal inter-ambulacra swell into
prominent cushions, and the narrow ambulacra form narrow valleys between them.

The mouth-opening is pentagonal, and always excentral ; the peristome is surrounded by
five prominent lobes, with which five expanded ambulacral petals alternate ; in the pori-
ferous zones near the mouth the pores are closely crowded in triple oblique ranks ;
these perforated petals form an oral rosette or a penta-phylloid floscule (Pl. XXXVII,
fig. 1 6, e).

The vent is infra-marginal ; it is in general oval, and surrounded by a distinct area,
which occupies the rostrated portion of the single inter-ambulacrum ; the long diameter
of the opening in general corresponds with the longitudinal axis of the test, although it
is sometimes transverse (Pl. XXX, fig. 2 4).

The apical disc is very small, and occupies the summit; it is composed of two
pairs of narrow, perforated, and a single rudimentary imperforate, ovarial plate; five
minute ocular plates, with central eyeholes, are interposed between the ovarials (Pl. XX XV,
fig. 3). The small madreporiform kody is attached to the surface of the right anterior
ovarial, and forms thereon a spongy eminence, which extends over the other discal elements
(fig. 3 9).

The tubercles are very small on the upper surface, but larger at the base; they are
surrounded by sunken areolas, have their summits perforated, and the inter-tubercular
space covered with close-set miliary granules (PI. XXXV, fig. 2 e, g).

51

392 PYGURUS

Pyeurus Micusini, Cotteau. Pl. XXXV, fig. 2 a, 6, ¢, d,e, f, g.

Pyeurus MIcHELINI. Cotteau, Etudes sur les Echinides Foss. de l’Yonne, p. 20;

pl. v, fig. 7, 1849.

— PENTAGONALIS, Wright, Ann. and Mag. of Nat. Hist., 2d ser., vol. ix, pl. iv, fig.
3, p. 313, 1851.

— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 88,
1854.

_ MIcHELINI. D’Orbigny, Pal. Frang. ter. Crétacés, t. vi, p. 301, 1855.

—_ Davoustianus. Davoust., Note sur les Foss. spéciaux 4 la Sarthe, p. 6, 1856.

_ MIcHELINI. Desor, Synopsis des Echinides Fossiles, p. 315, 1857.

— _— Cotteau et Triger, Echinides du département de la Sarthe, pl.
xiii, figs. 1—5, p. 65, 1858.

Test oval, or sub-pentagonal, very slightly indented before and rostrated behind ; upper
surface convex, under surface concave, with prominent, cushioned, basal inter-ambulacra ;
apical disc nearly central ; ambulacral areas and poriferous zones widely petalloid on the
upper surface, contracted at the lower fifth, and lanceolate at the apex; inter-ambulacra
with two flat ridges, which in each area extend from the disc to the mouth ; vent elliptical,
infra-marginal, lodged in a deep anal depression, with inclining sides; mouth-opening
large, pentagonal, excentral ; peristome surrounded by five prominent oral lobes and five
depressed phylloidal floscules.

Dimensions.—Height, one inch and one tenth; antero-posterior diameter, three inches
and one tenth; transverse diameter, three inches and one tenth.

Description.—tThe first specimen of this Pygurus I obtained was an elongated subpen-
tagonal variety, resembling in outline some of the Yorkshire specimens, and which I erro-
neously referred, in my ‘ Memoir on the Cassidulidee of the Oolites,’ to P. pentagonalis,
Phil. ; since that time I have collected a very fine series of this urchin, which I have care-
fully compared with M. Cotteau’s beautiful figures, and have no hesitation in referrig
them to Pygurus Michelini, Cott. Our English examples are larger than those from the
Sarthe, but in all the details of their anatomy they are identical with that form.

The test is nearly orbicular; in some specimens it is longer than broad, flattened, or
slightly concave before, and produced or rostrated behind ; the upper surface is convex, and
rises to a prominent vertex (fig. 2 c, d), which is sub-central, and from which the sides
decline unequally ; in consequence of the prominence of the single ambulacrum, the
posterior side forms a more regular inclined plane than the anterior side (fig. 2 @) ; the
border is very much undulated, and the base concave.

The ambulacral areas are widely petalloid on the upper surface, narrow at the border
and base, and again expanded near the mouth; they are sharply lanceolate at the apex,
and closely approximated at the dise (fig. 2 @) ; the poriferous zones on the upper surface
are formed of an inner row of round holes and an outer row of oblique, slit-like apertures,

FROM THE GREAT OOLITE. 393

the length of which gradually diminish from the middle of the petal upwards to the
apex, and downwards to about the lower fifth of the area, where the oblong pores are
reduced to simple pores, like those of the inner row (fig. 2 d); at the border the pairs of
pores lie close together, at the base they are much wider apart (fig. 2 4), and about half
an inch from the mouth they again greatly increase in number, and in the depressed
phylloidal floscule form a regular series of triple oblique pairs (fig. 2 4), with twelve rows
in each zone. .

The inter-ambulacral areas are uniformly convex above, the postero-lateral and single
inter-ambulacrum are of the same width, and the anterior pair are narrower at the under
surface ; these segments form prominent cushions, which are very tumid at the border, but
less so near the mouth; the most prominent part of each cushion is flattened at the
interspace between the ridges which radiate from the disc to the mouth.

The single inter-ambulacrum is produced, rostrated, and deflected ; at its infra-marginal
border is a deep anal depression, with prominent and inclined sides, at the bottom of
which the elliptical anus opens (fig. 2 4); the anal valley indents the border, and forms a
conspicuous notch in the margin when the test is viewed from behind forwards, as is well
shown in fig. 2 c, which likewise exhibits the undulations of the base.

The apical disc is remarkable for the size of the madreporiform body and the
smallness of the genital plates (fig. 2,/); the anterior pair are less than the posterior pair,
and the four are perforated; the single plate is posterior, and imperforate (fig. 3); the
small rhomboidal ocular plates alternate with the genitals, the very minute eyeholes are
perforated in the centre of the plates; the madreporiform body rises from the surface of
the right antero-lateral genital, extends over the surface of all the others, and occupies the
centre of the disc (fig. 3).

The large mouth-opening is sub-central and forward ; the peristome is pentagonal,
and surrounded by five prominent oral lobes (fig. 2 4) ; alternating with them are the five
depressed phylloidal terminations of the ambulacra, in which numerous pores are arranged
in triple oblique rows; this crowding together of the pores in regular order, imparts
an ornamental character to the five oral ambulacra.

‘The tubercles on the upper surface are very small, on each plate they are arranged in
four or five tolerably regular horizontal rows, and surrounded by sunken areolas ;
the inter-tubercular surface is covered with microscopic granules, placed so close together
that all the intermediate portion of the plates, when examined with a low magnifying
power, is seen to have a finely sculptured appearance. At the base the tubercles are
larger, and disposed with less regularity ; they increase in size, and are set closer together
at the border and on the convex surface of the five basal cushions, whilst they are still
larger and placed wider apart near the mouth-opening and on the sides of the ambulacra.

Affinities and differences.—This species has been frequently confused with Pygurus
depressus, Ag., which it very much resembles ; according to M. Cotteau, it is distinguished

394 PYGURUS

from that species by the following characters, ‘“ Par sa forme plus oblongue, plus allongée,
par ses ambulacres relativement plus larges, se rétrécissant moins brusquement et logés, aux
approches du péristome, dans des sillons plus droits et plus prononcés, par sa face inférieure
moins déprimée. Ces deux especes caractérisent d’ailleurs un horizon différent ; le Pygurus
‘ Michelini, propre aux couches de la Grande Oolite, se rencontre associé a /’ Hchinobrissus
clunicularis, au Collyrites ovalis, a 0 Hyboclypus gibberulus, tandis que le Pygurus depressus
se trouve dans le Kelloway ferrugineux avec le Collyrites elliptica, ? Echinobrissus Gold-
Fussti, le Pseudodiadema Calloviense, etc.”*
Pygurus Michelini, Cott., resembles Pygurus pentagonals, Phil., in its general outline ;
the former, however, is more depressed on the upper surface and more undulated at the
base, the anterior border is more concave, and the single inter-ambulacrum more

rostrated and deflected.

Locality and Stratigraphical position.—I found one small example of this species in
the Great Oolite at Minchinhampton, where it is excessively rare. I have collected
beautiful specimens in the Cornbrash near Trowbridge, Wilts, and my kind friend, the
Rev. A. W. Griesbach, presented me with the magnificent specimen figured at Pl. XXXV,
which he obtained from the Cornbrash at Rushden (Northamptonshire). I have two
inferior specimens from the Cornbrash near Yeovil. The specimen of this species I
first figured was said to have been found in the Lower Trigonia Grit (zone of Ammonites
Parkinsont) at Shurdington Hill, near Cheltenham. ‘This urchin has been collected from
a marly bed of Cornbrash near Fairford; it was found by my friend, J. Lowe, Hsq., in
the Cornbrash at Wincanton (Somerset), and I have seen specimens which were obtained
from the Bradford clay at Bradford, Wilts. It seems therefore that the range of this
species, like many other Hchinodermata which first appeared in the zone of Ammonites
Parkinsom, Ynferior Oolite, extended onwards through Fuller’s earth, Great Oolite,
Bradford clay, and Forest marble, into the Cornbrash, in which formation they all became
extinct.

The foreign distribution of this Pygwrus is the same as in our English Oolites. M.
Bouchard-Chantereaux kindly sent me a specimen which he collected from the Great Oolite
near Boulogne-sur-Mer.

It has been collected by M. Triger at ‘‘ Monné (carriére de Bernay), La Jaunelicre.
Hyéré, Noyen, Pécheseul, route de Coutilly, route de Suré 4 Mortagne.

“Tabl. de M. Triger, Bradford Clay, Ass. No 1, et Forest marble, Ass. No. 4.”

It has been found by M. Cotteau in the “Grande Oolite de Asmiéres, Chatel-
Gérard (Yonne),” and by M. Desor in the “ Marnes Vésuliennes du Jura Soleurois et
Argovien.’’+

* Cotteau et Triger, ‘ Echinides du departement de la Sarthe,’ p. €7.
+ Ibid. Ibid. p. 67.

FROM THE CORALLINE OOLITE. 395

Pycurus penraconaLis, Phil. Pl. XXXVI, fig. 1 a, 6, c, d; fig. 2 a, b.

ECHINANTHITES ORBICULARIS. Young and Bird, Geol. Surv. of Yorksh. Coast, pl. vi, fig. 5,
p. 213, 1822.
CLYPEASTER PENTAGONALIS. Phillips, Geology of Yorkshire, pl. iv, fig. 24, 1829.
ECHINOLAMPAS PENTAGONALIS. Morris, Catalogue of British Fossils, p. 52, 1843.
PyGURUS PENTAGONALIS. Forbes, in Morris’s Catalogue of Brit. Fossils, 2d ed. p.8, 1854.
_ — Desor, Synopsis des Echinides Fossiles, p- 314, 1858.

Test sub-pentagonal, emarginate, and concave anteriorly, wide in the middle, produced,
and deflected posteriorly ; upper surface convex, with a conical vertex, ambulacral areas
and poriferous zones widely petalloid in the upper two thirds of the dorsal surface, and very
narrow in the lower third; apical disc small, central, forming the vertex of the test ; under
surface concave ; basal inter-ambulacral cushions moderately prominent ; mouth-opening
small, sub-central, forwards ; peristome pentagonal, with five mammillated oral lobes and
five narrow ambulacral phylloidal floscules; vent elliptical, infra-marginal, situated in a

deep anal valley.

Dimensions.—a. Height, one inch and four tenths; transverse diameter, three inches
and three quarters ; antero-posterior diameter, three inches and nine tenths.

B. ‘Transverse diameter, three inches and a half ; antero-posterior diameter, three inches
and four tenths.

c. Height, one inch and one fifth; transverse diameter, three inches ; antero-posterior

diameter, three inches.

Description.—I have given the measurements of three different Yorkshire specimens of
this Pygurus. The specimen a was collected from the Coralline Oolite at Hildenley, near
Malton, by C. W. Strickland, Esq.; the specimen 8 was obtained near Scarborough,
and belongs to the Scarborough Museum; and the specimen c was collected from the
Lower Calcareous Grit near Scarborough. The examples from the Coralline Oolite are in
general much larger than those found in the Lower Calcareous Grit.

The test has an orbicular or sub-pentagonal form ; the anterior border is emarginate and
concave ; the antero-lateral border expands outwards to the middle of the test, where its
greatest diameter is attained. The postero-lateral border slopes inwards and backwards,
and forms a rostrated and deflected termination. ‘This is the form of the urchin figured
in fig. 1 a, 6, from the Calcareous Grit, which may be taken as a type of the species.
In the one from the Coralline Oolite (fig. 2 a) the test is altogether orbicular, and more
convex.

The ambulacral areas are remarkably petalloid (fig. 1 a) on the upper surface, the lower
third of the area is very narrow, the middle third much expanded, and the upper third

396 PYGURUS

lanceolate. The poriferous zones on the dorsal surface are formed of an inner row of oblong
holes, and an outer row of oblique, slit-like apertures, both rows being conjugate through
very fine sulci (fig. 2 6); at the lower fourth of the zone the slit-like outer pores contract
into simple pores like those of the inner row; at the border the pairs of pores lie close
together, whilst at the base they are wide apart ; near the mouth-opening the ambulacra form
phylloidal expansions, in which the pores lie crowded in triple, oblique pairs; the mam-
millated character of the oral lobes occasions a considerable contraction of the areas around
the peristome (fig. 1 4).

The inter-ambulacral areas on the upper surface are uniformly convex ; the anterior pair
are narrower than the posterior pair ; the single area, which is about the same width of the
latter, is produced, rostrated, and deflected (fig. 1 c), and in some varieties forms a caudal
prolongation; at the under surface, which is concave, the basal inter-ambulacra are moderately
convex ; the postero-lateral pair and single inter-ambulacrum are more so than the anterior
pair ; the anal valley is deep, with inclined sides, and the vent is large and elliptical
(fig. 1 4).

‘The mouth-opening is small, sub-central, and forwards ; it hes at the most concave part
of the base ; the peristome is pentagonal, and the five oral lobes, formed by the terminations
of the inter-ambulacra, have a prominent, mammillated character, which occasions a con-
traction of the ambulacra at the point where they join the peristome ; the protrusion of the
lobes removes the mouth itself far from the surface; the emargination of the anterior
border is more conspicuous at the base, and the anteal sulcus occasions a considerable
depression in the anterior border.

The tubercles are very small, and arranged in close-set rows, of which there are
five or six on each plate (fig. 2 0); the areolas are well defined; the tubercles at
the base are much larger than those on the upper surface ; they are more developed at the
border, on the declining sides of the cushions, and near the mouth, than on the convex
surface of these prominences, where they are small and closely aggregated together ; the
tubercles here are distinctly perforated (Pl. XX XV, fig. 2 7), whilst the intermediate surface
is covered with close-set microscopic granules. Few portions of the specimens I have
seen are sufficiently well preserved to show the sculpture; in those from the Calcareous
Grit it is almost always effaced, whilst in those from the Coralline Oolite it is concealed
by the Oolitic Coralline mud in which the most of them is enveloped.

The apical disc is small and central (fig. 1 d); the madreporiform body, which is
round, convex, and prominent, forms the vertex, the large ambulacral petals coverimg
nearly all the other portion of the upper surface. In fig. 1 ¢ the dorsum forms a conical
eminence through the development of the petals and disc (fig. 1 a).

Affinities and differences.—This species so closely resembles Pygurus Michelini, Cott.,
that it is only after a careful analysis of its specific characters the differences between them
are discovered. Pygurus pentagonalis is more convex on the upper surface, and more con-

FROM THE CORALLINE OOLITE. 397

cave at the base; the ambulacral petals on the dorsal surface are petalloid only in the
upper two thirds of their length, and very narrow and graceful in the lower third of the
areas (fig. ] a, ¢; fig. 2 a); the anterior border is emarginate and concave, and the under
side is impressed by the anteal sulcus; the posterior inter-ambulacrum is rostrated and
deflected ; the mouth-opening is small, and the oral lobes large and prominent. When
these characters, which are permanent in all the examples I have examined, are compared
with the homologous parts in Pygurus Michelini, which have been already described, the
distinction between the species will be readily determined. (Compare Pl. XXXV and
XXXVI.)

Locality and Stratigraphical position I have collected this urchin from the Lower
Calcareous Grit at Bullington-green, near Oxford, at Farringdon, Berks, from the same
rock at Scarborough, Castle Hill, and Gristhorpe Bay, on the Yorkshire coast. It is like-
wise obtained from the Coralline Oolite at Scarborough and Ayton, and at Malton and
Hildenley ; from the latter locality I have been enabled to study a fine large specimen,
kindly presented to me by C. W. Strickland, Hsq., and beautifully developed by him. My
kind friend, John Leckenby, Esq., communicated the beautiful specimen figured in
Pl. XXXVI, fig. 2 a, which came from the Coralline Oolite of Malton, and belongs to the
Scarborough Museum. ‘he small specimen (fig. 1 a, 4) was collected by my friend, Dr.
Murray, of Scarborough, from the Lower Calcareous Grit, near that town, and generously
given to me by him for this work ; Pygurus pentagonalis is, therefore, a true Corallian form,
and a most characteristic urchin of this formation, both in the Midland Counties as well
as in Yorkshire.

Pycurus costatus, Wright, nov. sp. Pl. XXXVII, fig. 1 a, 6, ¢, de, f.

Test sub-pentagonal, discoidal, much depressed at the upper surface ; ambulacral petals
large, costated, extending over four fifths of the upper surface; anterior border flat, emar-
ginate ; posterior border rostrated ; postero-lateral border very thin ; apical disc excentral,
forwards ; base flat ; mouth-opening large, sub-central ; peristome surrounded by five large
oral lobes and five spoon-shaped phylloidal floscules.

Dimensions.—One large specimen.—Height, one inch and one tenth; transverse
diameter and antero-posterior diameters, equal, four inches.

Specimen, Pl. XXX VII.—Height, nineteen twentieths of an inch ; transverse diameter,
three inches and three tenths ; antero-posterior diameter, three inches and three tenths.

Description —This urchin is remarkable for its discoidal form and for the prominent,
costated character of its dorsal ambulacra ; the anterior border is flat, the sides form obtuse
angles near the middle of the disc, and the posterior border is rostrated, but not deflected -

398 PYGURUS

the upper surface is very much depressed, and remarkable for the costated character of
the ambulacral areas, which are widely petalloid four fifths of the distance between the
disc and border (fig. 1 a). The poriferous zones consist of an inner row of oblong
pores, and an outer row of oblique, slit-lhke pores, conjugate throughout by fine sulci
(fig. 1 d); the transverse pores are separated by thin septa, on the surface of which a series
of minute granules are arranged; there are from seven to nine pair of pores opposite
each large inter-ambulacral plate (fig. 1 d). Near the border the pores are simple, and set
close together ; they continue so round the marginal fold ; at the base they are placed wide
apart, from their ambulacral plates being large and rhomboidal ; on the outer two thirds of
these segments, near the mouth, the areas suddenly expand (fig. 1 6), and between the oral
lobes they again as suddenly contract, forming thereby spoon-shaped depressions around
the mouth (fig. 1 e). On the sides of these depressions the poriferous zones present a
remarkable development (fig. 1 e); the pores form three crescentic rows on each side of
the depression, between the single pair and the marginal contraction (fig. 1 e). The
lobes are very large and mammillated, and form considerable eminences around the mouth,
their hip-hke forms extending over the border of the peristome (fig. 1 /).

The inter-ambulacral areas are of unequal width ; the antero-lateral pair are the narrowest,
the single posterior rostrated area the widest, and the postero-lateral pair of intermediate
dimensions ; their upper surface is almost uniformly sloped, and their basal portions
extremely flat; in most Pyguri the prominence of the inter-ambulacral cushions might
be considered a generic character; in this species, however, the convexity of these
basal segments is very inconsiderable (fig. 1 c).

The mouth-opening is large and sub-central, nearer the anterior border; the peristome
is pentagonal, and surrounded by five mammillated prominent lobes, which project, with
lip-hke processes, over the oral opening (fig. 1 4, 7); between the lobes the ambulacra are
much contracted, and beyond the lobes they form wide phylloidal expansions, on the sides
of which the poriferous zones consist of three concentric rows of holes (fig. 1 e) ; the struc-
ture of the oral lobes, phylloidal ambulacra, and trigeminal pores, form the most remarkable
features in this disciform species. '

The apical disc is small and sub-central, it forms the vertex of the test (fig. 1 e),
and the centre of a conoidal elevation, occasioned by the costated character of the am-
bulacral areas; the disc consists of four small perforated genital, a single imperforate
genital, and five very small ocular, plates; the small madreporiform body rises from the
surface of the right antero-lateral genital, covers the surface of the other plates, and forms
a.round spongy prominence in the centre of the disc (fig. 1 @).

The dorsal tubercles are very small, and arranged in four or five rows on each plate ;
they are surrounded by well-defined sunken areolas, and all the intermediate surface is
occupied by microscopic miliary granules, which are likewise encircled by sunken areolas ;
when viewed with an inch object-glass, the plates are seen to possess a delicately sculptured
surface (fig. 1 a) ; the basal tubercles on the sides of the inter-ambulacra, and the convex part

FROM THE CORALLINE OOLITE. 399

of the lobes are fewer in number, and larger in size (fig. 1 4), than those of the dorsum, and
their surface is perforated ; the tubercles on the convex portions of the inter-ambulacra are
very small, and placed so close together that the borders of the areolas form hexagonal
figures ; the basal ambulacra are destitute of tubercles, and the plates are covered only
with miliary granules ; the nakedness of the surface clearly displays the size of the plates,
and their peculiar figure, with the distant pores in the narrow zones in this region of
these segments.

The oblong vent is infra-marginal, and the anal valley is shallow, with sloping sides,
on which some larger tubercles are disposed.

Afinities and differences—This species resembles Pygurus orbiculatus, Leske, so
beautifully figured by M. Cotteau; Pygurus costatus, however, has a much larger test, it
is more depressed at the upper surface, and has more prominent, costated, ambulacra ; the
pentagonal border, is more rostrated behind, and more emarginate before ; the larger mouth-
opening has more prominent lobes and larger phylloidal ambulacra, and the test presents
an ensemble of characters by which these two allied forms may readily be distinguished.

Pygurus costatus resembles Pygurus Marmonti, Beaud., from the Kelloway ferrugineux
of the Sarthe, in the general disciform shape of the test and flatness of the base, but in
the specimen of P. Marmonti before me the poriferous zones are petaloid to the
border, the vent is removed inwards some distance from the margin, and the test has,
moreover, an orbicular circumference.

The depression of the dorsum, thinness of the border, angularity of the sides, flatness
of the base, and prominence of the dorsal ambulacra, clearly distinguish Pygurus costatus
from its other Oolitic congeners, and I am unacquainted with any other foreign form
beside those enumerated with which to compare our urchin.

Locality and Stratigraphical position.—This species was collected from the Lower
Calcareous Grit of Oxfordshire and Wiltshire ; the specimen I have figured was found near
Oxford, and I have another from the same rock near Calne. It is not a common
species, as I have rarely seen it in collections of Calcareous Grit fossils. The specimen

I have figured was most kindly given to me for this work by my friend, the Rey,
P. B. Brodie.

or
wo

400 PYGURUS

Pyeurus Buumensacuit, Koch and Dunker. Pl. XXXVIII, figs. 1 and 2.

CiyprastER BuumenBacutt. Koch and Dunker, Norddeutschen Oolithgebildes, pl. iv
HER OS Oy iy LEB ia
Pyeurus BLUMENBACHII. Agassiz and Desor, Catalog. raisonné des Echinides, Annales
des Sciences Naturelles, 3° série, t. vii, p. 162, 1847.
— = D’Orbigny, Prodrome de Paleéont. Stratigr., t. i, p. 26, étage
14°, 1850.
— — Wright, Ann. and Mag. of Nat. Hist., 2d series, vol. ix,
p. 312, 1851.
— — Forbes, in Morris’s Catalog. of Brit. Fossils, 2d ed., p. 88,1854.
—_ — Cotteau, Etudes sur les Echinides Fossiles (Yonne), pls. xxxiii
and xxxvi, p. 233, 1856.
— — Desor, Synopsis des Hchinides Fossiles, p. 313, 1858.

2

Test thin, sub-quadrate, with a sinuous border; upper surface elevated anteriorly,
gradually declining posteriorly; apical disc excentral forwards, forming the vertex;
ambulacral areas and poriferous zones broadly petaloid on two thirds of the dorsal
surface; anterior border emarginate and concave; sides crescentic; posterior border
produced, rostrated, and much deflected; under surface concave, with prominent basal
inter-ambulacra. Mouth-opening large, sub-central; peristome with five very prominent
oral lobes, and five phylloid ambulacral floscules. Tubercles in general small, but larger
on the anterior part and at the base.

Dimensions.—Height, one inch and a quarter; antero-posterior diameter, two inches
and one fifth; transverse diameter, two inches and three tenths.

Description —The Oolitic Pyguri, in general, have a remarkable similarity in their
external form; so much so, that it frequently requires a careful examination of their
characters to distinguish allied species from each other. It is, however, altogether
different with Pygurus Blumenbachi, which forms a remarkable exception to the general
rule. In this singular urchin the outline is sub-quadrate, the anterior border is emargi-
nate and concave, and deeply indented by the central sulcus (fig. 1 a, fig. 2 a); the lateral
parts of the margin are convex ; the posterior border consists of a double sinuous line, in
the centre of which is the single inter-ambulacrum, this forms a convex, rostrated pro-
minence, slightly deflected downwards (fig. 1 a, fig. 2 a). The upper surface presents a
most singular profile (fig. 1 7); the anterior half is relatively much elevated and turgid,
and the posterior half slopes gently downwards to the border.

The dorsal ambulacra are broadly petaloid at the upper half and extremely narrow at
the lower half, and their wide, lanceolate apices are closely approximated around the dise
(fig. 1 a, fig. 2a).

The poriferous zones consist of an inner row of round holes and an outer row of

FROM THE CORALLINE OOLITE. 401

oblique, slit-like apertures, which are limited to the upper half of the rows (fig. 2 4) ; in the
lower half, the pores are simple, like those of the inner row; at the border, the holes are
so minute they cannot be distinguished ; at the base they are placed wide apart (fig. 1 4),
and near the mouth the ambulacra expand into phylloid expansions, which, near the
peristome, are contracted by large oral lobes.

‘The inter-ambulacral areas are very unequal in width and development; the anterior
pair are narrow, convex, and prominent ; they rise nearly perpendicular, forming with the
base an angle of 80°, and near the vertex curve backwards; the plates on the inner sides
of the areas, as well as on the single ambulacrum, carry much larger tubercles than
the other dorsal plates (fig. 1 a, fig. 2 a); the posterior pair and the single area incline to
an angle of about 35°. The upper surface thus acquires the remarkable anterior elevation
which gives so marked a character to this species, and allies it with a Neocomian form—
Pygurus Montmollin, Ag. The single inter-ambulacrum possesses a central elevated
portion on its upper surface, made more apparent by two lateral depressions commencing
at the imner zone of the postero-lateral ambulacra, which gradually rise and blend with
the central elevation (fig. 1 c); this is continued downwards and backwards, and forms
the rostrated portion of the single area, which is slightly deflected at its termination
(fig. ¢, d).

The apical disc is small and excentral, and nearer the anterior border ; it consists of
four small, perforated, ovarial plates (fig. 3), a single smaller, imperforate plate, and five
very small ocular plates, perforated near their centre; the spongy, madreporiform body
rises from the surface of the right antero-lateral plate, extends into the centre of the disc
covering the inner portions of the ovarial plates, and having the ocular plates disposed
around its circumference.

The under surface is concave, and very much undulated, the ambulacra forming narrow,
depressed valleys from the border to the mouth, and the basal inter-ambulacra extremely
convex eminences between them (fig. 1 6, c); near the mouth-opening their terminal
portions are developed into five tumid lobes.

The large sub-central mouth-opening is directly beneath the apical disc; it is con-
sequently nearer the anterior than the posterior border; the peristome is surrounded by
five oral lobes, which alternate with five phylloid ambulacra, filled with several longitudinal
rows of pores (fig. 1 4).

The anal valley is a slight depression, formed out of a prominent portion of the basal
inter-ambulacrum ; it has declining sides, covered with large tubercles, and is quite infra-
marginal; the vent is oval, and elongated in the antero-posterior diameter (fig. 1 4,
figalie)s

The tubercles on the dorsal surface are very small, and arranged in five concentric rows
on each plate (fig. 2 6) ; they are encircled by sunken areolas, and the intermediate space
is covered with close-set miliary granules (fig 2¢). On the antero-lateral inter-ambulacra
and single ambulacrum the tubercles are considerably larger (fig. 1 a, fig. 2 a); at the

4.02, . PYGURUS

base they are still larger, and their deep areolas form hexagonal cells on different portions
of the base.

Affinities and differences.—In its general characters, but more especially in the oblique,
tumid, conoidal elevation of the anterior half of its upper surface, Pygurus Blumenbachir,
Koch, resembles three other congeneric forms—Pygurus Montmollini, Ag., P. Orbignianus,
Cott., and P. Rogerianus, Cott., from each of which it is distinguished, however, by specific
characters ; the first and second are Neocomian, and the latter Kimmeridge species. It
differs, according to M. Cotteau, from Pygurus Montmollini, Ag., in its greater size, less’
elevated upper surface, and more rostrated posterior border. It differs from Pygurus
Orbignianus, Cott.,* equally by its size, by its less conical upper surface and more tumid
anterior border, by its petalloid ambulacra being more slender, by its inter-ambulacral
tubercles being closer together and more irregularly disposed. Pygurus Rogerianus, Cott.,+
more closely resembles P. Blumenbachi, but it appears to M. Cotteau, who has carefully
compared these two species, that P. Rogerianus is distinguished from the latter by the test
being much longer than it is wide, by the upper surface being more depressed, its
tubercles being less numerous, and its intermediate granules disposed in regular and
concentric series. ¢

The only two English specimens of this urchin which I know are those figured in our
plate; the largest belongs to the Museum of Practical Geology, and was collected by the
officers of the Geological Survey; the other is in my cabinet. ‘These Pyguri are much
smaller than the very fine specimens which my friend M. Cotteau has so well figured
and described in his work, hence the comparison which he has made was between these
fine large specimens and the other species above enumerated, and. which all belong to the:
secondary rocks of France. M. Cotteau’s specimen measures in height 34 millimétres = one
inch and nine twentieths ; antero-posterior diameter, 87 millimetres = nearly three inches
and a half; and transverse diameter, 86 millimétres = three inches and four tenths.

Locality and Stratigraphical position.—The specimen collected by the officers of the
Geological Survey was obtained from the Coral Rag at Abbotsbury, Dorsetshire, where it
is extremely rare. My specimen was said to have been procured from the Inferior Oolite,
near Yeovil, but this I have discovered to be a mistake. I have reason to believe that it
was collected from the Lower Calcareous Grit at Bullington Green, near Oxford, asso-
clated with Crdaris Smithit, Wr., and Lchinobrissus scutatus, Lamk. .

The foreign distribution of this species is as follows: In France it characterises the

inferior and superior stages of the Corallien. M. Cotteau collected it in “ Calcaire blancs

* ©Catalogue raisonné des Echinides du Terrain Néocomien,’ p. 12.

+ “Note sur les Echinides de l’étage Kimmeridgien de l’Aube,” ‘ Bull., de Géol. Soc. de France,’ 2° série,
t. xi, p. 356.

{ ‘Etudes sur les Echinides Fossiles du departement de l’Yonne,’ p. 238.

FROM THE CORALLINE OOLITE. 403

et Pisolitique” of Chatel-Censoir, and of Coulanges-sur-Yonne, where it is very rare ; it is
found more frequently in the “ Couches Coralliennes supérieures” of Baily, of Thury, and
of Tonnerre ; the specimens collected from the latter locality by M. Rathier were in fine
preservation, and were nearly as large as those found at Thury.

This species has likewise been found by MM. Cotteau and Royer in the “ Calcaires a
Astartes de l’Aube et de la Haute-Marnes.”

The original German specimen was found, according to Koch and Dunker, in the
“krystallinischen Dolomitquadern des oberen Korallenkalkes am Waltersberge bei
Eschershausen.”’*

Professor Roemer kindly sent me a specimen of Pygurus Blumanbachii, Koch, which
was collected from the so-called Portland-Kalk, zone of Pterocera Oceani, at Hildesheim,
Hanover. This rock Dr. Oppel ¢ considers to be the equivalent of our Kimmeridge clay,
and not of the true Portland stage. The occurrence of this urchin in the zone of P/erocera
Oceani strengthens my learned friend’s opinion, as MM. Cotteau and Rathier have
already found it in the “Calcaires a Astartes,” in PAube, and Haute-Marne, which
is the true equivalent of the Astartekalke of Lindener Berg, and of the environs of
Hildesheim.

Pycurus Puriuipsi, Wright, nov. sp. Pl. XXXIX, fig. 1, a, 4, ¢, d.

Pycurus Puitiipsii. Wright, Report on British Oolitic Echinodermata, British Associa-
tion Reports, p. 402, vol. for 1856.

Test nearly orbicular, rather longer antero-posteriorly than transversely; rounded
before, slightly produced behind; upper surface very much depressed; sides rounded ;
anal valley very near the border; ambulacral areas narrow ; poriferous zones petaloid on
five sixths of the dorsal surface ; apical disc small, nearly central, four rows of tubercles
on the large plates; inter-ambulacra with slight central triangular elevations, which
occasion corresponding tumidities at the border; anal valley wide and deep, causing an
emargination of the posterior border.

Dimensions —Height, one inch; antero-posterior diameter, nearly four inches; trans-
verse diameter, three inches and three quarters.

* Norddeutsch. Oolithgebildes, p. 38.
+ Die Juraformation, p. 763.

404. PYGURUS

Description —Yhe beautiful specimen figured in Pl. XXXIX is the only one of
this form I have seen. The upper surface, sides, and outer part of the base, are in
fine preservation, but the greater portion of the under side is concealed by the matrix.

The test is thin, and has a sub-orbicular circumference; it is rounded before, and
slightly produced behind, the difference between the length and width being only one
quarter of an inch.

The dorsal ambulacra are narrow, only slightly expanded in their upper half, and
terminating in sharp, lanceolate apices around the disc (fig. 1 a); they have six rows of
tubercles, disposed alternately on the plates, so that they form double oblique rows, with
three tubercles in each (fig. 1 d).

The poriferous zones, of moderate width, are petalloid five sixths of the distance
between the border and disc; as im all other Pyguri, the holes of the inner row are
nearly round, those of the outer row are oblique or nearly transverse slits, which about
equal in length the width of one half of the area (fig. 1 c); between each slit-like aperture
there is a partition of the test, on the surface of which a series of ten granules are very
regularly arranged (fig. 1 7) in a single row; at the borders the pores lie close together,
in single pairs, but they are wider asunder at the base.

The inter-ambulacral areas are of unequal width; the anterior pair are about one
sixth narrower than the posterior pair; they are formed of long, narrow plates, which are
bent to an obtuse angle in the middle; along the line of these angles the surface of the
test is slightly elevated, producing in the middle of each area a triangular elevation, the
base of which is at the border, and the apex towards the disc (fig. 1 a); the margin, in
like manner, exhibits a fulness corresponding with the bases of these elevations.

The apical disc is absent, and the space for its reception is small in comparison with
the size of the test.

The tubercles are beautifully preserved in this species (fig. 1, c, d); on the upper
surface each plate carries four horizontal rows, which are arranged in zigzag order
above one another; the tubercles are all perforated, and crenulated, and raised on small
mammillary eminences ; the areolas which encircle them are wide and well defined ; a circle
of miliary granules surrounds the areolas, and other granules fill up all the intermediate
spaces; the granules are surrounded by narrow areolas, which impart a highly sculptured
character to the surface of the test.

The anal valley lies so near the posterior border that it produces an emargination
thereof (fig. 1 @); when viewed from behind, the vent is seen quite in the border of the
rostrated portion of the single inter-ambulacrum (fig. 1 4).

The tubercles at the border and base are much larger and more prominent than those
on the upper surface; and the areolas present a regular hexagonal disposition around the
margin and at the base.

I have only seen one specimen of this urchin, embedded on a portion of Coralline
Oolite limestone; the test is very thin, and has been fractured, the joint having been

FROM THE CORALLINE OOLITE. A05

closed again by crystallization in the rock ; the base is nearly entirely concealed by adhering
matrix.

Affinities and differences.—The flatness of the upper surface and the form of the
ambulacral areas in this species closely resemble Pygurus Hausmanni, but the test is
narrower before, wider near the middle, and more rostrated posteriorly, than the usual
specimens of that large species. I have, therefore, described it under a distinct name,
not, however, without misgivings of its propriety, as a series of specimens might exhibit
intermediate links, by which the two forms would blend into one type. This is one of
the many difficulties to be encountered in describing new species from single examples,
which in the present instance is unavoidable; time and additional specimens, however,
will prove how far my doubts are well-founded or otherwise.

Locality and Stratigraphical position.—This species was collected from the Coralline
Oolite at Malton, Yorkshire, where it is extremely rare; the specimen I have figured is
the only one I have seen.

History.—This urchin was first recorded in my memoir ‘ On the Stratigraphical Distri-
bution of the Oolitic Echinodermata,’ afterwards published as one of the ‘ Reports of the
British Association for the Advancement of Science,’ for the year 1856. It is now figured
for the first time, and dedicated to my learned friend, Professor John Phillips, of Oxford.

Pyeurus Havsmanni, Koch and Dunker. Pl. XL; Pl. XXX, fig. 2.

CiyprasTeR HavsMANNI. Koch and Dunker, Versteinerungen des Ool. Gebirg., tab. iv,
fig. 3, p. 38, 1837.
— — Leymerie, Stat. Géol. et Min. du dép. de l’Aube, p. 239, 1846.
Pycurus HavusMannl. Agassiz et Desor, Cat. raisonné des Echinides, An. des Sciences
Naturelles, 3° serie, tom. vii, p. 162, 1847.
— — D’Orbigny, Prodrome de Paléontologie, tom. ii, p. 26, 14° étage,
1850.
— — Cotteau, Note sur les Echid. de l’étage Kimmeridg., Bull. Géol.
Soc. de France, 2° serie, tom. xi, p. 317, 1853.
— — Forbes, in Morris’s Catalogue of British Fossils, 2d ed., p. 83,
1854.
— — D’Orbigny, Paléontologie Frangaise Ter. Cretacés, t. vi, p. 301,
1856.
= — Cotteau, Etudes sur les Echinides Fossiles, p. 328, 1856.
_— — Desor, Synopsis des Echinides Fossiles, p. 314, 1858.
— GIGANTEUS. Wright, Oolitic Echinodermata, Report of the British Associa-
tion for the Advancement of Science for 1856, p. 396.

406 PYGURUS

‘Test large, sub-circular, sometimes oval, and slightly rostrated posteriorly ; upper sur-
face flattened, and much depressed; base sub-concave, rounded anteriorly, and slightly
produced posteriorly ; ambulacral areas on the upper surface nearly equal-sized and lan-
ceolate ; poriferous zones petalloid near to the border; apical disc small, nearly central ;
inter-ambulacral areas broad and flat, with a very distinct zigzag median suture ; margin
very thin; base sub-concave ; mouth-opening small, situated nearer the anterior than the
posterior border. :

Dimensions.—a. Antero-posterior diameter, six inches and four tenths; transverse
diameter, six inches; height indeterminable.

B. Antero-posterior diameter, five inches and one fourth; transverse diameter, four
inches and nine tenths ; height, one inch and three tenths.

Description—This large discoidal urchin is remarkable for the great size it attains ;
nearly all the specimens I have seen are broken, and more or less imperfect, so that the
identification of the species is extremely difficult. Last summer, however, I met with
one which had retained the form of its circumference, as well as the shape of its upper
surface, and this example enabled me to identify the species I had formerly named Pygurus
giganteus with Koch and Dunker’s Clypeaster Hausmanni. It is, therefore, extremely
interesting to find this urchin in the same horizon of the Coralline Oolite of Malton,
the zone of Cidaris Blumenbachii, the one it occupies in the Korallenkalk of northern
Germany.

Pygurus Hausmanni has in general a sub-circular outline, rather inclining to an oval,
its transverse diameter being always less than its antero-posterior measurement; the
anterior border is rounded, and in specimen B the posterior border is a little produced ;
the upper surface is moderately convex in the smaller specimen, but is very much flattened
im the larger ones, and the anterior half 1s more convex than the posterior half.

The ambulacral areas are narrow and lanceolate; they have six rows of small tubercles
in their widest part, which are not all arranged in a horizontal series on the two corres-
ponding plates of the area, but are disposed thereon so as to form oblique V-shaped rows.
Plate XX XIX, fig. 2, exhibits this arrangement of the tubercles. The poriferous zones are
moderately wide, the holes of the inner row are round, those of the outer row are slit-like,
of which there are eight pairs opposite each large plate (fig. 2); the septum between each
pair of holes supports on its upper surface a horizontal row of nine small granules. ‘The
ambulacral areas and poriferous zones form together a series of five elegant leaf-shaped
petals, which are enlarged in the middle, become lanceolate near the disc, and are con-
tracted at the circumference; the poriferous zones are petaloidal six sevenths of their
length ; and near the lower seventh the pores approximate; in their course round the
margin, and across the base they remain close together in pairs.

FROM THE CORALLINE OOLITE. 407

The inter-ambulacral areas are of unequal width, the anterior pair are the narrowest,
and the posterior pair and single area are the widest; the former in B measures two
inches and four tenths, and the latter, which are about the same width, measure two inches
and nine tenths across. The long plates forming these areas are bent in the middle
(PI. XL), and their surface is covered with four rows of small, regularly arranged,
crenulated and perforated tubercles, raised on bosses, and surrounded by sunken areolas ;
the inter-tubercular portion of the plates is covered with close-set miliary granules.
(Pl. XX XIX, fig. 2.)

The small apical disc is situated at the vertex, rather nearer the anterior than the
posterior border; the discal elements are soldered together, and nothing but the four
ovarial holes, and small central madreporiform body are visible in the specimens I have
hitherto seen.

In all the specimens of this urchin I have examined in different collections, the
under surface is covered with the Oolitic matrix, which adheres so firmly that it is
impossible to remove it; the structure of the base is therefore unknown to me. M. Cotteau,
however, states, “That at the inferior surface, in his specimen, the ambulacra converge
in a straight line to the mouth; they are narrow, bordered with pores, set wide apart,
and enclosed in very apparent depressions, which alternate with the elevations of the
inter-ambulacral areas.”

’ The anal opening is situated just below the posterior border, it has an oval form, its
long diameter corresponding to the antero-posterior diameter of the test.

The mouth-opening, according to M. Cotteau, is excentral, nearer the anterior border,
the peristome is pentagonal, and surrounded with five prominent oral lobes.

The test of this species is very thin and delicate, a circumstance which may account
for the fractured condition in which it is so often found; in general it is met with in
masses of Oolitic limestone, from which it has to be cut out with great care.

Afimties and differences.—This gigantic urchin so much resembles Pygurus Phillipsit,
Wr., in all the leading points of its structure, that it is possible the latter may be only
a young form of Pygurus Hausmanni ; it requires, however, more specimens than I have
hitherto had at my disposal to state this as a fact. Pygurus Hausmanni in its magnitude
resembles Pygurus Icaunensis, Cotteau, but it differs from the latter in having its upper
surface more depressed, its ambulacral areas narrower, and in preserving their petaloidal
figure near to the border, whilst in P. Icaunensis theyre wider in the upper half, and
much narrower in the lower half; the base of this urchin is likewise more concave and
the inter-ambulacra more prominent and cushioned. P. Hausmanni differs from
Pygurus pentagonalis in having the dorsal surface more depressed, the general outline
more sub-circular, the ambulacral areas narrower above and wider below, and the single
inter-ambulacrum less rostrated than in the latter species. The prominence and elevation
of the ambulacra in Pygurus costatus with its pentagonal form readily distinguish it from

53

AO PYGURUS.

Pygurus Hausmanni, although the great depression of the test in both these species pro-
duces a close resemblance between them.

Locality and Strategraphical posttion.—This large species has hitherto been found in
England, only in the Coralline Oolite, at Malton, Yorkshire, and always in the thick
bedded limestones of that formation, associated with Clypeus subulatus, Cidaris florigemma,
Echinobrissus dimidiatus and Collyrites bicordata.

In France it has been collected, according to M. Cotteau, in the “‘ Calcaires a Astartes
de l’Aube,” at the environs of Longchamps, by M. Royer, and at Polisot by M. Leymerie ;
M. d’Orbigny states that it is found in the “ étage corallien’’ of Tonnerre, and Thury,
(Yonne).

In Germany it was collected by Koch and Dunker* in the “ Oberen Korallenkalk,”
at Kleinenbremen, near Biickeburg, associated with Astrea? helianthoides, Goldf.,
A. agaricites, Goldf., Terebratula lacunosa, Schl., and Cidaris Blumenbachi, Mist.

History.—This large urchin was described and figured in 1837 for the first time by
Koch and Dunker; it has been subsequently described by M. Cotteau, and mentioned in
the different works enumerated in the synonyms of this species.

« Beitrage des Norddeutch Oolithgebirg, p. 38.

FOREIGN JURASSIC PYGURUS. 409

NOTES

On Foreign JURASSIC SPECIES OF THE GENUS PYGURUS, NEARLY ALLIED TO BritisH
FORMS, BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITES.

‘ : eee
Pyeurus acurus, Agassiz. Catalogue raisonné des Hchinides, p. 104.

Test elongated, and depressed, sensibly enlarged before and behind, its form
resembling Pygurus productus from the Neocomian, posterior border rostrated, vent
oblong, and infra-marginal.

Formation.—Inferior Oolite of Nantua.

Collection.—M. d’Orbigny.

Pyeurus DEpRessus, Agassiz. Syn. Pygurus depressus, Cotteau and Triger. Echinides
du départ. de la Sarthe, pl. xx, fig. 1—6; p. 90.

Test sub-orbicular, or elongated, slightly depressed before, and much rostrated
behind ; upper surface elevated and uniformly convex, inferior surface depressed ; deeply
concave in the middle, and having the basal inter-ambulacra much cushioned; discal
summit nearly central; ambulacral areas widely petaloid ; poriferous zones very large, con-
tracted at the lower fourth of the dorsal surface, apical disc small, slightly prominent and
excentrally forwards; vent elongated, opening near the posterior border in a deep
depression ; mouth-opening, excentral, nearer the anterior border; peristome penta-
gonal, surrounded by five oral lobes, with which five ambulacral petals alternate.

Dimensions.—Height eight tenths of an inch; antero-posterior diameter, one inch and
four tenths ; transverse diameter, two inches and one quarter.

Formation.—Kelloway ferrugineux, Ass. No. 2, M. Triger ; Chauffour, Sarthe.

Collections —MM. Triger, Cotteau, one specimen in my cabinet collected by M.
Scemann, at Chauffour, Sarthe, and kindly sent me for this work.

410 FOREIGN JURASSIC PYGURUS.’

Pycurus (EcHINANTHUS) oRBICULATUS, Leske. Syn. Pygurus orbiculatus, Cotteau and
Triger, Echinides du la départ. de la Sarthe, pl. xix, fig. 6—7, p. 88.

Test large, sub-circular, longer in length than in width; upper surface a little
elevated, sub-conical, and depressed at the border; base almost flat; basal inter-
ambulacra not prominent ; summit slightly excentrally forwards; ambulacral areas lanceo-
late ; poriferous zones very wide, and petaloidal almost to the margin; apical disc small,
slightly excentral; vent oval, infra-marginal, situated in a deep depression. Mouth
opening small, sub-central nearer the anterior border; peristome pentagonal, surrounded
by five small oral lobes, with which five wide ambulacral petals alternate.

Dimensions. —Height, nine tenths of an inch; antero-posterior diameter three inches ;
transverse diameter, two inches and eight tenths.

Formation.— Kelloway ferrugineux, Ass., No. 2, M. Triger, Coulans, Chauffour, Mont-
bizot,.environs of Mamers, Sarthe.

Collections. —MM. Michelin, Triger, Guéranger.

Prcuaus Marmont, Beaudouin. Syn. Pygurus Marmonti, Desor, Synopsis des Echinides
Fossiles (p. 316). _

Test large, sub-circular, much depressed on the upper surface; ambulacral areas
lanceolate ; poriferous zones wide, petaloidal to the margin; base flat ; inter-ambulacral
basal cushions distinctly flattened on the surface; mouth-opening small, pentagonal, and
sub-central ; peristome surrounded by five oral lobes, which alternate with five ambulacral
petals ; vent small, oval, situated in a deep depression removed a short distance from the
border. M. Cotteau suggests that it might be necessary to unite this species with P.
orbiculatus, from which it differs in having a more circular form, and likewise in the
vent being removed a little farther inwards from the border ; it is found in the same zone
with that urchin, and may be only a variety of it.

Dimensions.—Height, nine tenths of an inch; antero-posterior diameter three inches

and one quarter ; transverse diameter, three inches.

Formation —“ Kellovien de Chatillon sur Seine, Mamers Estrochey (Cote d’Or),
Grande Oolite de Normandie.” Desor.

One of the two specimens in my cabinet was collected by M. de

Loriere from the “ Kitage Kellovien Chauffour, Sarthe.’ The other

was obtained from the Kelloway ferrugineux Estrochey (Cote d’Or).

FOREIGN JURASSIC PYGURUS. 41]

Collections. —-MM. Michelin, Deslongchamps, Cotteau, my cabinet.

/ /
Pyaurus Icaunrnsis, Cotteau. tudes sur les Echinides Foss., pl. xxxvii, xxxviii.

Test large, sub-circular, length and breadth nearly equal; upper surface elevated
and conoidal; under surface ‘eoncave ; ambulacral areas petaloid, very narrow below,
dilated in the middle, and lanceolate above; poriferous zones wide, and petaloidal two
thirds the distance between the disc and border; base deeply concave; basal inter-
ambulacral areas very convex and prominent; mouth-opening excentral, small, pentagonal,
nearer the anterior border, surrounded by five oral lobes, and five wide ambulacral petals ;
anal opening large, oval, infra-marginal, situate in a deep depression. This large species
resembles P. Hausmanni, of which M. Desor suggests it may probably be a variety ; the
plaster mould in my collection exhibits very decided specific differences between it and the
discoidal urchin I have identified with the German species.

Dimensions.—Height, one inch and a quarter; antero-posterior diameter four
inches and a half; transverse diameter, four inches and three

tenths.

Formation.—Calcaréo-siliceous strata of the Inferior Coralline Oolite at Druyes,
(Yonne). Rare.

Collections. —M. Cotteau; only two specimens known. A plaster mould of the
figured specimen in my collection.

Pyeurus tenuis, Desor. Synopsis des Echinides Fossiles, p. 315.

“Test large, circular, much dilated; border thin, almost trenchant ; summit central ;
ambulacral petals very long, petaloidal almost to the margin.” Desor.

Formation —* Portlandien inférieur (Astartien) d’Oberbuchsitten (Canton de Soleure),
Oolite Astartienne de Laufon (Jura Soleurois), Delémont.” Desor.

Collections.—Mus. de Neuchatel; M. Michelin.

413 FOREIGN JURASSIC PYGURUS.

Pyevurus Jurensis, Marcou. Mem, Soc. Geol. de France, 2% serie, tom. in, p. 114.

«Test dilated, and rostrated ; summit excentral; ambulacral areas large, extending
petaloidal almost to the border; under surface much undulated; anal opening infra-
marginal.” Desor.

Formation.—‘“ Portlandien supérieur (Virgulien) de Suziau prés Salins, des environs
de Morteau, Gray, Haute-Saone.

Portlandien moyen (Ptérocérien moyen) de Montbéliard.” Desor.

Collections. —MM, Marcou, Thurmann, Jaccard, d’Orbigny.

ON

Pi toe) PER AP PE CAL DISTRIB UT TON

OF THE

OOLITIC ECHINODERMATA.*

Att the classes of the animal kingdom, when viewed in relation to their stratigraphical
distribution, are not of the same value to the palzontologist. Some Mollusca, as the
Conchifera and Gasteropoda, have a much greater extension in time than the Cephalopoda,
and among Radiata, the Echinodermata and Anthozoa may be adduced as examples of
classes whose life was alike limited; in estimating the value of paleontological evidence,
therefore, it is necessary to take into consideration this important fact, which has not
received the attention it is so justly entitled to.

The Echinodermata, although occupying a low position in the animal series, in a
zoological point of view, still afford the paleontologist most important data for discussing
questions relative to the distribution of species in time and space; it is well known, for
example, that the Silurian, Devonian, and Carboniferous rocks are all characterised by
distinct forms of Crinoidea, most of which are limited in their range to the different
stages of these great groups. It is the object of this chapter, however, to show that the
species of Oolitic Echinodermata had a like limited range in time, and that the different
stages of the Oolitic formations are characterised by species which are special to each.

Dr. William Smith was doubtless aware of the value of the Echinodermata in strati-
graphical geology, for he carefully noted the different species known to him which
characterised the different subdivisions of the secondary rocks ; and itis a remarkable fact,
in connection with this subject, that although our knowledge of the species of this class

* The stratigraphical distribution of the Echinodermata, originally written for this work, was commu-
nicated, in the form of a memoir, to the Geological Section of the British Association, at the meeting held
at Cheltenham, in August, 1856. The Council did me the honour, to order the communication to be
printed entire among their Reports ; for this reason it appeared in the ‘ Report of the British Association
for the Advancement of Science for 1856,’ and is now corrected down to the present date.

A14 STRATIGRAPHICAL DISTRIBUTION OF

has been nearly quadrupled since the publication of his works,* still the outlines sketched —
by the hand of our great master remain nearly the same as laid out by him.

I have already shown that the test of the Echinodermata constitutes an internal and
integral part of the body of the animal, participating in its life, intimately connected with
the organs of digestion, respiration, and generation, as well as with those of vision and
locomotion, and consequently having many of the distinctive characters of the organism
indelibly impressed on different parts of the skeleton. The individual plates composing
the columns of the test of the Ecuinorpea, and the ossicula forming the skeletons of the
ASTEROIDEA, OpHIvROIDEA, and ORINOIDBA, are organized after distinct plans ; they are

_ therefore of great value in determining the species, as the specific characters are often
well preserved on even fragmentary portions of the skeleton ; for this reason the remains
of these animals are of the highest value in stratigraphical geology, and second in
importance to no other class of the animal kingdom.

In the Ecuinorpxa the body is spheroidal, oval, depressed or discoidal, and enclosed
in a calcareous test or shell composed of ten columns of large plates constituting the
inter-ambulacral areas ; and ten columns of small plates constituting the améulacral areas,
which segments are separated from each other by ten rows of holes constituting the
poriferous zones. The external surface of the plates is studded with tubercles of different
sizes, in the different families ; to these the spines are articulated, by a kind of ball-and-
socket joint, which are of different sizes, forms, and dimensions in the different families,
and serve to characterise the genera and species.

At the summit of the test is the apical disc, composed of five genital plates perforated
for the passage of the ovarial and seminal canals; and five ocular plates notched or per-
forated for lodging the eyes: in one family, the Satunrapz#, an additional or suranal
plate, composed of one or many pieces, is introduced within the circle formed by the
genital and ocular plates.

There are two great apertures in the shell, one for the mouth, which is always at the
base ; the other for the anus, which occupies different positions on the test; in one section
it is in the centre of the upper surface, directly opposite to the mouth, and surrounded by
the genital and ocular plates; in a second section the vent is external to the circle of
genital plates, and never opposite to the mouth, but situated in different positions in
relation to that opening, being placed on the upper surface, on the sides, the border, the
infra-border, or the base, in the different groups.

The mouth is often armed with a complicated apparatus ‘of jaws and teeth,
or it is sometimes edentulous, and provided with lobes formed of the plates of the test
itself.

The Astrrorpn have a depressed stelliform body provided with five or more lobes or
hollow arms, which are a continuation of the body, and contain prolongations of the

* «Strata identified by Organized Fossils,’ 4to, 1816.—‘ Stratigraphical System of Organized Fossils,”
4to, 1817.

THE OOLITIC ECHINODERMATA. 415

viscera. The mouth is always below and central; two or four rows of tubular retractile
suckers occupy the centre of the rays; and in two families an anal vent opens at the
central or sub-central part of the dorsal surface. The complicated skeleton 1s composed
of numerous solid calcareous ossicula, variable as to number, size, and arrangement in the
different genera which they serve to characterise. ‘Their coriaceous integument is often
studded with pedicellaria and calcareous spines of various forms; they have a spongy
madreporiform body situated on the upper surface of the disc near the angle between two
rays ; and reptation is accomplished by retractile tubular ambulacral suckers.

The Opnrurorpra have a distinct depressed discoidal body surrounded by long slender
rays, i which there is no excavation for any prolongation of the viscera; they are special
organs of locomotion, independent of the visceral cavity, and provided with spines which
are supported on their sides; they have no pedicellariz ; the mouth is basal and central,
surrounded by membranous tentacula, and they have no anal vent. The skeleton is
composed of a series of plates which form the disc or centrum, and the long slender rays
are sustained by numerous elongated vertebra-like ossicula, having numerous plates or
spines disposed along the borders of the rays to assist in reptation. The form, structure,
arrangement, and covering of the discal plates, and of the ossicles of the rays, afford good
characters for distinguishing the genera.

The Crrnorpna have a distinct bursiform body formed of a calyx, composed of a definite
number of plates, provided with five solid rays, independent of the visceral cavity, and
adapted for prehension ; they have a distinct mouth and vent, no retractile suckers, and
the ovaries open into special apertures at the base of the arms. ‘The skeleton is extremely
complicated, being composed in some genera of many thousands of ossicula articulated
together, the number, form, and arrangement of which are determinate in the different
families, the multiples of five being the numbers which in general predominate ; the central
plate of the calyx is supported on a long jointed column composed of circular, pentagonal
or stelliform plates, the articulating surfaces are sculptured with crenulations which
interlock into each other ; in many genera the stem was attached by a calcareous root to
the bed of the sea, and supported the calyx and arms upwards like a plant; in others it
appears to have been moveable, and was used as a point of suspension from submarine
bodies, the calyx and arms having had a pendent position.

The mouth is central and prominent, and the vent opens near its side; the arms are
mostly ramose and multiarticulate, and when extended form a net-like instrument of
considerable dimensions.

The four orders of Echinodermata thus briefly described are the only ones found
fossil in the oolitic rocks, and of these by far the largest number of species belong to the
EcuinorpEa ; for this order I have proposed the following classification, which differs in
many essential particulars from that of previous authors.

As the mouth is always basal, central, subcentral, or excentral, the excentricity being
invariably towards the anterior border, this aperture does not afford a character of primary

54

A16 STRATIGRAPHICAL DISTRIBUTION OF

importance, although when taken in connexion with others it is valuable in the definition
of families.

The position of the anal opening affords a good primary character ; in one section the
vent opens wethinm the centre of the apical disc, surrounded by the genital and ocular
plates ; in another section the vent opens without the apical disc, and is external to, and
at a greater or less distance from, the genital and ocular plates; these two sections may
be thus defined.

EcHINOIDEA ENDOCYCLICA.

A. Test circular, spheroidal, more or less depressed, rarely oblong ; mouth central
and basal; vent in the centre of the upper surface directly opposite the mouth, and
surrounded by five perforated genital and five ocular plates. Mouth always armed with
five powerful calcareous jaws, formed of many elements disposed in a vertical direction.

ECHINOIDEA EXOCYCLICA.

B. Test sometimes circular and hemispherical, oftener oblong, pentagonal, depressed,
clypeiform or discoidal ; mouth central or excentral ; vent external to the circle of genital
and ocular plates, never opposite the mouth, situated in different positions in relation to
that opening: four of the genital plates are generally perforated; the fifth is in general
imperforate. Mouth sometimes armed with jaws, but oftener edentulous. Jaws
disposed in a more or less horizontal direction.

The structure of the ambulacral areas and poriferous zones, the form, number, and
arrangement of the tubercles and their spines, the presence or absence of fascioles or
semitze, the size and form of the elements of the apical disc, and the position of the anus,
afford collectively good characters for defining the genera.

The minute details in the structure of the plates; the size, form, and number of the
tubercles on each ; the form and arrangement of the pores in the zones; their proximity
or remoteness from each other; the general outline of the body, which has only certain
limits of variation; the character of the sculpture on the plates; the form of the areolas ;
the greater or less prominence of the base; the size of the tubercles; the presence or
absence, the size and arrangement of the granules forming the areolar circle; the com-
pleteness or incompleteness of the same; the width of the miliary zone, the number and
size of the rows of granules composing it; the length of the spines; the form of their
stems; the character of the sculpture thereon ; the size of the head, the prominence and

THE OOLITIC ECHINODERMATA. ALT

milling of the ring,—are all details of structure which individually and collectively afford
good specific characters, as they are persistent details which are more or less developed on
every considerable fragment of the test and spines of EcurnorpEa.

Taking these characters for our guidance, I have grouped the genera, already so nume-
rous by the discovery of extinct forms, into the following natural families :

A TABLE, SHOWING THE SECTIONS AND FAMILIES OF THE ECHINOIDEA,

ORDER. SECTIONS. FAMILIES.
CIDARID#.
Section A.
HEMICIDARID®.
Echinoidea endocyclica. DIADEMADZ.
Vent within the genital plates, | Boyinips.
always opposite the mouth. (| Qarpnrap He.
Orper—ECHINOIDEA . ( EcHINOCONID#.
CoLLYRITID#&.
Section B. ECHINONID®.
Echinoidea exocyclica. EcHINANTHID#.
Vent without the genital plates, EcHINOLAMPID#.
never opposite the mouth. CLYPEASTERIDA.

\ ECHINOCORIDS.
l SPATANGID.

*
418 STRATIGRAPHICAL DISTRIBUTION OF
A Table showing the Stratigraphical distribution of
LOWER DIVISION.
FAMILIES,
GENERA, AND SPECIES. pee PA oe aa ene jt ol rl
tome | ahaa | mer) Ma aaa a ee ed
Fam. CipaRIDz&. | |
Cidaris Edwardsu, Wright . 4 * S| |
Ilminsterensis, Wright | 2 |
Mooreui, Wright . : : | fee Se &
Fowleri, Wright . : : | sid aye | ne *
|
- Bouchardiu, Wright : : 208 We at Ay ee
Wrightii, Desor . : : ves a a *
confluens, Forbes . ; , tr. ae eee se be %
Bradfordensis, Wright . : oe oe fe ae ne Ea ai rs BR Be
florigemma, Phillips
Smithu, Wright
spinosa, Agassiz
Boloniensis, Wright
Rabdocidaris Moraldina, Cotteau . 36 *
maxima, Minster . : 80% 50 he a *
Diplocidaris Desori, Wright . ; at Re! x o
Wrightii, Desor . : : aoe ane ae *
Cotteauana, Wright 5 , ae at at ite *
Fam. HEeMIcIDARgIDA.
Hemicidaris granulosa, Wright .. is ae. ae ie si *
pustulosa, Agassiz . ; : a ee a ay ae *
Stokesii, Wright . : : Aue a ae ae cit at aa es
Luciensis, d’ Orbigny ; : ye ne ee ee 0 re a rE * a |
minor, Agassiz . ; ‘ hts at Ss ee ace ne SA Wa ¥: |
Ramsayii, Wright . ; : a nt uh so sa * |

THE OOLITIC ECHINODERMATA. 419

the genera and species of the Oolitic Echinodermata.

MIDDLE DIVISION. UPPER DIVISION.

OBSERVATIONS AND FOREIGN
LocaLiriegs.

re

Forest
Marble.

Kelloway} Oxford | Lower | Coralline} Upper | Kimme- | Portland} Portland} Purbeck
Cornbrash.| Rock. | Clay. Calc. Grit.| Oolite. | Calc. Grit.|ridge Clay.| Sand. | Oolite. | Beds.

Fe e * a n. _.. | France, Germany, and Switzer-
land.

Switzerland.
Boulogne-sur-Mer.

France.

Germany.

Ranville, France.

Ranville, France.

Lue, France.

Ranville, France.

20 STRATIGRAPHICAL DISTRIBUTION OF

FAMILIES,

GENERA, AND SPECIES.

LOWER DIVISION.

Hemicidaris Bravenderi, Wright
Wrightii, Desor
Icaunensis, Cotteau
intermedia, Fleming
Davidsonii, Wright

Purbeckensis, Forbes

Fam. DIADEMaD&.
Pseudodiadema lobata, Wright
Mooreii, Wright
Wickense, Wright
depressum, Agassiz
Parkinsoni, Desor .
pentagonum, M‘Coy
homostigma, Agassiz
Bailyi, Wright
vagans, Phillips
Bakerize, Woodward
versipora, Phillips .
hemisphericum, Agassiz
radiatum, Wright .
mamillanum, Roemer
Hemipedina Bechei, Broderip
Bowerbankii, Wright
Tomesii, Wright
Jardinii, Wright

Etheridgii, Wright

Inrerior OOLITE. Great OoLire.
FSS ae EE
Murchi- Humpane, Parkinsoni| Fuller’s |Stonesfield] Great | Bradford

sone zone, S@nus zone. Earth. Slate. Oolite. Clay.

zone.

———— es

a

I i i

THE OOLITIC ECHINODERMATA.

MIDDLE DIVISION. UPPER DIVISION.

|
<<, oN

Forest Gornbrash Ralomny, Oxford Lower | Coralline| Upper | Kimme- | Portland | Portland | Purbeck

Marble. tock. Clay. |Cale. Grit.} Oolite. /Cale. Grit.Jridge Clay.| Sand. Oolite. Beds.

AQ) °

OBSERVATIONS AND FOREIGN

Locaitigs.

France.
France and Germany.
Boulogne-sur-Mer.

France.

France.

France and Switzerland.

Switzerland.

France and Switzerland.

France and Germany.

ee

STRATIGRAPHICAL DISTRIBUTION

FAMILIES

GENERA, AND SPECIES.

Hemipedina Bakeriz, Wright

perforata, Wraght .
tetragramma, Wright
Waterhousei, Wright
Bonei, Wright
Davidson, Wright
Woodwardu, Wright
microgramma, Wright
Marchamensis, Wright
Corallina, Wright .
tuberculosa, Wright
Morrisn, Wright

Cunningtoni, Wright

Pedina rotata, Wright

Smithii, Forbes

Fam. Ecuinipaz.

Glypticus hieroglyphicus, Goldfuss
Magnotia Forbesii, Wright

Polycyphus Normannus, Desor

Deslongchampsii, Wright

Stomechinus germinans, Phillips

intermedius, Agassiz
bigranularis, Lamarck
microcyphus, Wright
gyratus,, Agassiz

nudus, Wright

Lias.
OS Sao
Lower Middle | Upper
Lias. Lias. Lias.

INFERIOR OOLITE.

OF

LOWER DIVISION.

Great Oo.ite.
je eee

Baan Se aS
Murchi- Humphrie- Parkinsoni] Fuller’s |Stonesfield) Great | Bradford
sone zone. ae zone. Karth. Slate. Oolite. Clay.
ok
*
*
*
*
*
|
|
|
|
|
ox *
|
* *
*
|
|
*
BS *

THE OOLITIC ECHINODERMATA. 423
MIDDLE DIVISION. UPPER DIVISION.
ow. OBSERVATIONS AND FOREIGN
ee Loca.irigs.
Forest Kellow; Oxford Lo Coralli Upper Ki - | Portland | Portland | Purbeck
Marble, |Commbrash.| poor | “Clay. locale Get, | Outta” (ome ee ridgeClay,| Seri. | Golite, | Beds
| France.
|
*
*
*
*
*
*
oo
2s
es Se ate tae pe ee France, Germany, and Swit-
zerland.
e ae Be a oe ie Bs bh en ... | Ranville and Luc, France.
x ae bas ag. ee aa 2 its te ... | Ranville, France.
Ranyille, Port-en-Bessin,
France.
5 France and Switzerland.
| |
| *

424 ? STRATIGRAPHICAL DISTRIBUTION OF

LOWER, DIVISION.
FAMILIES,
Lras. InFERIOR OOLITE. Great OoLirte.
GENERA, AND SPECIES. a oe AE
Lower Middle Upper | Murchi- Humpbric; Parkinsoni| Fuller’s |Stonesfield} Great | Bradford
Lias. Lias. Las. {son zone. eae zone. Earth. Slate. Oolite. Clay.
Fam. SALENIADA.
Acrosalenia minuta, Buckman 6 a
crinifera, Quenstedt : F a aus %
Lycetti, Wright . : . Si set ak ie oe “4
pustulata, Forbes *
Wiltonii, Wright
Loweana, Wright .
spinosa, Agassiz % soe *
hemicidaroides, Wright . A
decorata, Haine

Fam. ECHINOCONID®.

Holectypus depressus, Leske .

*
*
*

hemispheericus, Desor

*

oblongus, Wright .

Pygaster semisuleatus, Phillips. A He a *

*

conoideus, Wright . 4 3 1 Jt oa *
macrostomus, Wright
Morrisii, Wright

umbrella, Lamarck

Fam. EcHINOBRISSID&.

Echinobrissus clunicularis, Lihwyd

*
*
*«

Woodwardii, Wright
orbicularis, Phillips
quadratus, Wright .
Griesbachii, Wright

THE OOLITIC ECHINODERMATA.

MIDDLE DIVISION. UPPER DIVISION.

Se

Forest Kelloway | Oxford Lower | Coralline| Upper | Kimme- | Portland
Marble, (Crash. Rock. | Clay. {Cale Grit, Oolite. (Cale. Grit.|ridge Clay.| Sand.

— || —_—_— | _—_|____ | | | |

*
*
*
* *
* *
*
*
*
*
*
* *
* *
*
*
*

Portland | Purbeck
Oolite. Beds.

OBSERVATIONS aND ForREIGN

LocaLirtigs.

Pliensbach bei Boll, Wirttem-
berg.

Ranville, Chatel - Censoir,
France; and Soleure,
Switzerland.

Bar-sur-Aube, Yonne, France.

France, Germany, Switzer-
land.
France, Germany, Switzer-
land.

Druyes, Chatel - Censoir,
Coulanges - sur - Yonne,
St. Mihiel, France.

France, Germany, Switzer-
land.

Mamers, Sarthe, France.

426

FAMILIES,

GENERA, AND SPECIES.

| Echinobrissus dimidiatus, Phillips .
scutatus, Lamarck .
Brodiei, Wright
Clypeus Plotii, Klein
Agassizil, Wright
altus, M‘Coy .
Michelini, Wright .

Hugu, Agassiz

rimosus, Agassiz
Miulleri, Wright . : 5

subulatus, Young and Bird

Fam. CoLLYRITIDA.

Collyrites ringens, Agassiz
ovalis, Leske .
bicordata, Leske
Hyboclypus agariciformis, Forbes .
caudatus, Wright
gibberulus, Agassiz

ovalis, Wright

Fam. EcHINANTHID®.
Pygurus Michelini, Cotteau
pentagonalis, Phillips
Blumenbachii, Koch §- Dunker

Phillipsii, Wright .
Hausmanni, Koch § Dunker

costatus, Wright

STRATIGRAPHICAL DISTRIBUTION OF

LOWER DIVISION.

Lias. INFERIOR OOLITE. Great OoLite.
(aaa aR nl AG a
Lower | Middle | Upper | Murchi- Humphrie-\p,insoni| Fuller’s |Stonesfield| Great | Bradford
Lias. Lias. las. |sonee zone: aoa zone. Earth. late. Oolite. Clay.
* *k *k *
*
*
* *
*
*
*
*
*
* *
*
*
*
* * *

a

aa ge
Forest Kell
Marble, |Comnbrash. Rock”

Oxford
Clay.

MIDDLE DIVISION.

Lower | Coralline

Cale. Grit.

Oolite.

Upper

UPPER DIVISION.

Kimme-

Pp
Cale. Grit.jridge Clay.

Portland
Sand.

Portland | Purbeck
Oolite. Beds.

OBSERVATIONS AND ForREIGN
LocaLirixrs.

France, Germany, Switzer-
land.

France and Switzerland.

Conlie, Mamers, Sarthe, France.

Pécheseul, Sarthe, France.

| France and Switzerland.

| France and Switzerland.
France and Switzerland.

France and Switzerland.

Bayeux, France.

France and Switzerland.

|
|
|
|
|
|
|

France and Switzerland.

|
|
| France and Germany.
|
{
|
!

France and Germany.

428 STRATIGRAPHICAL DISTRIBUTION OF

LOWER DIVISION.
FAMILIES,
Lras. InFERIOR OOLITE. Great Ooxire.
GENERA, AND SPECIES. iim Pain Ta (sao = ian aL
| tamst | MBme | Gpees farts sane paso] Mn Rae) Oe | Pea
Order ASTEROIDEA.
Fam. URasTERID®.
Uraster Gaveyi, Forbes . : . Be *
carinatus, Wright . : : ee ES
Fam. SoLasTERID#.
Solaster Moretonis, Forbes . : i zi ya se ae we e ae *
Fam. GONIASTERID.
Goniaster Hamptonensis, Wright . be a “ as He oe ee fa *
obtusus, Wright . : : an BAS a %
|
Fam. ASTERIDA.
Tropidaster pectinatus, Forbes 3 ae o
Astropecten Hastingsie, Forbes. ue i |
Orion, Forbes 5 ° - ae *
Phillipsu, Forbes . : : An *
Leckenbyi, Wright é : bet 308 a x
Scarburgensis, Wright . : ae ae a - & .
Cotteswoldiz, Buckman . 2 - nae x fen ae 33 * r
Wittsii, Wright . : : ae le A a sh re +, *
Forbesi, Wright . : re Ac eat IRE Re sab abe x |
claveeformis, Wright
rectus, M‘Coy |
Luidia Murchisonii, Williamson . i * |
Plumaster Ophiuroides, Wright . x |

THE OOLITIC ECHINODERMATA.

MIDDLE DIVISION. UPPER DIVISION.

SET a

Forest 5 Kelloway | Oxford
Marble. Cornbrash. Rack lay.

———|_

Lower | Coralline} Upper | Kimme-

Portland | Portland | Purbeck
Cale. Grit.) Oolite. | Cale. Grit.|ridge Clay. i

Sand. Oolite. Beds.

429

OBSERVATIONS AND ForrIGn
LocaLITIES.

Sd

430 STRATIGRAPHICAL DISTRIBUTION OF

FAMILIES,

GENERA, AND SPECIES.

Order OPHIUROIDEA.
Fam. OPHIURIDA.
Paleeocoma Gaveyi, Wright
Milleri, Phillips
Egertoni, Broderip

tenuibrachiata, Forbes

Brodiei, Wright
Murravii, Forbes

Griesbachii, Wright

Order CRINOIDEA.
Fam. PENTACRINID!.
Pentacrinus tuberculatus, Jf//er
scalaris, Goldfuss 5
| basaltiformis, Miller
Goldfussii, M‘Coy .
robustus, Wright .
punctiferus, Quenstedt
Johnsonii, Austin .
dichotomus, M‘Coy
Phillipsii, Wright .
Milleri, Austen
Austen, Wright
subsulcatus, Goldfuss
subteres, Goldfuss .
Extracrinus Briareus, Miller .

subangularis, Miller

Lras.
ZT ia aaa
Lower Middle Upper
lias. Lias. Lias.

*

% i

*
|
le
!

*k

ok

*

ok

*

*

*

*

BE
*k

InFerion Oonire.

LOWER DIVISION.

Great OOLITE.

Murchi- Humphrie- Parkinsoni| Fuller’s |Stonesfield} Great | Bradford

sone zone.

sianus
zone.

—s

zone.

Earth. Slate. Oolite, Clay.

THE OOLITIC ECHINODERMATA.

451

——__—_—_———,

Porest Kellowa
farble, |Co™Mbrash | eck

MIDDLE DIVISION.

Oxford
Clay.

Lower
Cale. Grit.

Ovlite.

Calc. Grit.}ridge Clay.| Sand.

UPPER DIVISION.

| Coralline | Upper | Kimme- | Portland | Portland | Purbeck

Oolite. Beds.

OBSERVATIONS AND FOREIGN
LocaLities.

France, Germany.
France, Germany.

France, Germany.

Germany.

France.

Germany.
Germany.
France, Germany.

France, Germany.

a ena

56

432

FAMILIES,

GENERA, AND SPECIES.

Fam. APIOCRINIDA.
Apiocrinus Parkinsoni, Schlotheim .
elegans, Defrance .
exutus, M‘Coy
Millericrinus Pratti, Gray
obconicus, Goldfuss
Konincku, Wright

echinatus, Schlotheim

STRATIGRAPHICAL DISTRIBUTION OF

LOWER DIVISION.

Lower
Lias.

INFERIOR OOLITE.

medic Humphrie-

sone zone. SIBNUS.
zone.

Lias.
SS
Middle Upper
Lias. lias.
17 12

10

Great OoLITE.

: :

Fuller’s |Stonesfield} Great | Bradford
Karth. Slate. Oolite. | Clay.
*
*
*
*k
*
8 28 9

166 Species.

ECHINOIDEA ..
ASTEROIDEA ...

OPHIUROIDEA

CRINOIDEA ...

THE QOOLITIC ECHINODERMATA. 433

MIDDLE DIVISION. UPPER DIVISION.
OBSERVATIONS AND ForEIGN
LocaLirizs.
~ —-"[5- Se ‘
Forest Cornbrash.| Kelloway | Oxford Lower | Coralline| Upper | Kimme- | Portland | Portland | Purbeck
Marble. | Rock. Clay. | Cale. Grit.) Qolite, | Calc. Grit.jridge Clay.| Sand. Oolite. Beds,
Ranville, Mamers, France;
Alsace, Germany.
*
x ae a2 EP wipe cc ... | France, Germany.
rs 21 0 0 11 24 0 4 1 1 1

Pccesccss LLG

Beeeasiocne > 18
2 SCORES ODE 22—166

434 STRATIGRAPHICAL DISTRIBUTION OF

From the above Tables, it appears that the English Oolitic rocks are known at present
to contain 166 species of fossil Echinodermata, of which 119 species belong to the Order
Ecuinorpra ; 18 species tothe Order AstERompEA; 7 species to the Order OpHtuRomDEA ;
and 22 to the Order Crinoipua. All the species belonging to the families Crparipa,
Hemiciparip#, Diaprmapa, Ecuinip&, Satentapa, Ecatnoconipa, EcHInosRissIDZ,
Contyritip#, EcHinantuip#®, and EcurnoLampPip2, have been figured in this work.

The AstERoIpEA, OpHrurorpEA, and Crinorna, will form the subject of a second
Monograph. An analysis of the Tables gives the following distribution of the species in
each stage :

Lower Lias s : . a ~. 10 Species.
Middle Lias . 2 : : : lyf 20
Upper Lias A iN # ‘ WD 35
Inferior Oolite 8 . 4 5 . Ad aS
Fuller’s Earth 5 : R : ; 1 AS
Stonesfield Slate 5 c é ; Bn 24.3) nS
Great Oolite 3 j : i 5 BS
Bradford Clay : 4 6 : Biss!) op
Forest Mazble , ‘ i : SES. ay
Cornbrash_ . ‘ ‘ F 5 fo Qil is
Oxford Clay and Kelloway . 3 : s 10 2
Lower Caleareous Grit . 5 5 s fone 5
Coral Rag : ; 3 . . 24 2p
Upper Calcareous Grit . eae a
Kimmeridge Clay . : 5 ; Sis) 4 ”
Portland Sand ; é 5 : Saal 0
Portland Oolite A 1 Fy)
Marine Purbeck Beds 6 1

The Lias forms appear to be special to the three subdivisions of that formation, so well
characterised by the species of Ammonites which indicate these three zones of Liassic life.
The Inferior Oolite contains forty-nine species, of which forty-three are HEcurnorpsEa,
three AsrrromEa, one Opnivrorna, and two Crinorpna; of these, ten species
extend into the Great Oolite, and nine species pass into the Cornbrash; the Inferior
Oolite has therefore thirty species which up to this time have not been found in any
other formation ; all the species from the Lias to the Cornbrash inclusive became ‘extinct
before the deposition of the Kelloway rock and Oxford clay. The Fuller’s earth has
yielded one species, and the Stonesfield slate contains eight species, several of which are
special to this fissile rock. ‘The Great Oolite has yielded twenty-eight species, of which
ten extend into the Cornbrash, fourteen are special to the Great Oolite stage, and four are
common to the different stages of the lower division of the Oolites. The nine species
of the Bradford clay are mostly common to this argillaceous bed, and the Great Oolite
limestone on which it rests. The Forest Marble contains eight species, of which four are
common to this rock and the Cornbrash, which contains twenty-one species, many of

THE OOLITIC ECHINODERMATA. 435

which are found in older formations; with the deposition of the Cornbrash the lower
division of the Oolites terminate, and with that formation all the species of Echinodermata
found in these rocks became extinct.

The middle division of the Oolites contains far fewer species than the lower. The
Kelloway rock and Oxford clay, so rich in Cephalopoda, have not in England, as far as I
can learn, yielded any remains of Echinodermata. The Lower Calcareous grit, Coral
rag, and Upper Calcareous grit, have several species in common; of the eleven species of
the Lower Calcareous grit, six are common to it and the Coral rag, which contains twenty-
four species ; I have not ascertained how many, if any, pass into the Upper Calcareous
crit; in fact, these three stages represent in reality only one stratigraphical zone of life.

The Kimmeridge clay up to the present time is known to contain only four species,
which are all special to it. There is one species in the Portland sand, one in the Portland
Oolite, and one in the Marine Purbeck beds. The Portland Oolitic limestone is said to
contain the remains of several Echinoderms, although I have been able to obtain only
two specimens of the same species for examination from that formation.

BIBLIOGRAPHY OF THE ECHINODERMATA,

. Merrett. Cur. ...

. CHARLETON. GUALT,

C

ARRANGED IN

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438 BIBLIOGRAPHY OF THE ECHINODERMATA,

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1718.
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1719.

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1728.

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1732.

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1734.

ARRANGED IN CHRONOLOGICAL ORDER. 439

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57

440

1735.

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1743.
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ARRANGED IN CHRONOLOGICAL ORDER. 44]

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mineralogischen und chemischen Betrachtungen erldutert, und
mit Kupferstichen versehen. Aus dem Danischen iibersetzt.’
Copenh. und Leipz., 1764, 8vo, fig.

1760. D’Annone. J. J. .......... uGeat Acta Helvetica physico-mathematico anatomico - botanico - medica,

‘ figuris aeneis illustrata. Basil, vol. iv, 4to.

MAGN PELORER a Die. BEE) co-teae at unlits - «xt Tentaminis lithologici de Polyporitis et Zoophytis petrefactis
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UZo0s SoHuLzE., Cabs) $s s.ctevss setcs.. Betrachtung der versteinerten Seesterne und ihrer Theile. In 4to,
mit Kupfert.

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WAGi in UL TS a DOWN. 62 2.0 se shine dele eiasie sae An account of an Encrinus or Star-fish, with a jointed stem. ‘ Phil.
Transac.,’ vol. ]1i, part 1, p. 357.

WAG Ze STROMA ELANS) 002.0 based cop once Physisk og cekononomisk Beskrivelse over Fogderiet Séndmor belig-

gende i Bergens stift i Norge. Soroz, 4to, fig.

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EAGG iP ANDEEA: Oey Goshen vs.a0aheaata~s Briefe aus der Schweiz nach Hannover geschrieben in dem Jahre
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POS BER BRAN Ds Bayes care sin8/s geen acer Dictionnaire universel des Fossiles propres et des Fossiles acciden-
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17S DU Ree eS ae ee Re Memoires de Mathématique et de Physique, presentés 4 l’Académie
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AGS ENVALEERTU SH dmiGa sages ce nae Mineralogie oder Mineralreich, von ihm eingetheilt und beschreiben ;

ins Deutsche iibersetzt. Von J.D. Denso. Zweite Auflage, mit
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1766. Mutter. Po. L. Sr. ............ Deliciea Nature Selecte, oder auserlesenes Naturalien-Kabinet, ete. ;
ehemals herausgegeben von G. W. Knorr und fortgesetzt von
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GVEA OB GARI LEASE coaeineecekabeeeeeee Spicilegia Zoologica. Tome i, Berlin, 4to, 1767-74.

PARSONS. JAMES 4.5.2 onc.cs-cs002 Remarks on a Petrified Echinus (Cidaris papillata, Leske). ‘ Phi-
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LAG As DAVILA. “DONG Ey Mite mecereceees.. Catalogue systématique et raisonné des Curiosités de la
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1768. NVC Hoh: Pa BL DP CU een oes aa Die Naturgeschichte der Verstemerungen, zur Erlauterung der

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44.2

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1814.

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NWN CCh IG Chel Bic dom ioetstanedoatepeoia Lithologische Beobachtungen ; I. Ein Versteinerter Ostracion, und
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WROTHA IRA (OTN oo) pagasaronasndodacs Zoologii Danicize Prodromus, seu Animalium Danie et Norwegiz

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BETIS. Oper Boncsseecssteeena estes The Natural History of many curious Zoophytes, systematically
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CUVIER IG. oem een eee ee Tableau Hlémentaire del’ Histoire naturelledes Animaux. Paris, 8vo, fig.

Fausas DE St.-Fonp. B.......... Histoire naturelle de la Montagne de St.-Pierre de Maestricht.
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1817. Cuvier. GEORGE .................. Régne Animal distribué d’aprés son organisation. Paris, 4 vols.
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1822. PARKINSON. JAMES ............... Outlines of Oryctology. Lond., 8vo, fig.

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1823. Deuue Curase. STEF. ..:........ Memorie sulla storia e notomia degli animali senza vertebre del regno

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1824] DEFRANCE. M...42.....0.2..2.0052 Tableau des corps organisés Fossiles. Paris, 8vo.

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1824. Stokes. CHARLES ............... On Three Specimens of Fossil Echini. ‘Trans. Geol. Soc.,’ ser. 2,
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1825. Gray. JonN Epwarp ........... An attempt to divide the Echinide, or Sea-eggs, into natural fami-
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Cuvier’s Animal Kingdom, with supplementary additions to each
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Acass1z. Louis

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On Echinoneus lampas. ‘Trans. Geol. Soc.,’ ser. 1, I, table 3,
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1841. Stsmonpa. Eve. ..................Monographia degli Echinidi fossili del Piemonte Torino. 4to, fig.
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1842-51. Konincx. L. DE

1842 DESOR ED a aeeee aaa ee

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1842.
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BIBLIOGRAPHY OF THE ECHINODERMATA,

JAN SET Teas vali ee van le

99 ee tee ee teers sees

PATE TP PTH A os cece. cosas

MULLER und TroscHEeL

Poxrttock. JosrpH ELLISON ...
Morris. JOHN............-.--+--
SISMONDA. EUG. ............-+.

KCEREHDAING ZG coo engscseovose ces

Pictet. F. T.

Mourcuison. Sir RopERick ...

(CravaNMe, JELS 1Wincgoascose9n¢02050

AGassiz et DESOR

Scumipt. F. A.

DEY MERIB. As. cies leescecee

...Kentniss der Ostlichen Alpen.

...Grundriss der Versteinerungskunde.

eet e tees eecees

Proposed Arrangement of the Hchinodermata, particularly as re-
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Monographie d’ Echinodermes.
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System der Asteriden mit Zwolf Kupfertafeln. 1842.

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A Catalogue of British Fossils. 8vo. ;

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Quatriéme Monographie, des Dys-

Tor. 8vo, fig.

Giessen, 4to, 21 plates.

Traite élementaire de Paléontologie. 4 vols. 8vo, plates, 1844-46.

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Catalogue raisonné des Familles, des genres, et des espéces de la
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Description des Fossiles recueillis par M. Thorent dans les Falaises
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Peto. GRASS ADBING | idee coat ates Description des Oursins Fossiles du département de I’Isére.
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Yorganisation des Echinodermes. Extrait du tome xx des ‘ Mem.
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1848. Forbes, EpwarpD ............... Memoirs of the Geological Survey of Great Britain. ‘On the
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1849. Se dey PODS ve hel Memoirs of the Geological Survey of the United Kingdom.
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nS49.. BRONN: H.G. lei cece ey. Index Paleontologicus. 3 Band. 8vo, 1849.
1849. Acassiz. LovIs .................. Lectures on Comparative Embryology. Boston, &8vo, woodcuts.
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Mag. Nat. Hist.,’ vi, p. 343.

1849. D’OrBieny. ALCIDE ............. Cours Hlémentaire de Paléontologie et de Géologie. 2 vols., plates.

1849. HatMe. JULES ......:.....:....05.. On Milnia decorata. ‘Ann. des Sc. Nat.,’ 3me série, tome xii,
p: 217, pl. 2.

1849-56. CorrEat. GUSTAVE ......... Etudes sur les Echinides Fossiles du département de l’Yonne.
Tome I, Terrain Jurassique. Plates. Tome II, Terrain Crétacé.

1849-50. MULLER. JOHANN ............ Ueber die Larven und die Metamorphose der Holothurien und

Asterien. ‘Vorgetragen in der Konigl. Akademie der Wissen-
schaften zu Berlin.’

1850. Se Te So Anatomische Studien iiber die Echinodermen. ‘Miiller’s Archiv,’’
Heft 11, 1850.

1850. EN) We ey naca arene Berichtigung und Nachtrag zu den Anatomischen Studien iiber die
Echinodermen. ‘Miiller’s Archiv,’ Heft iii.

1850. Beha VIR os uta exe Fortsetzung der Untersuchungen iiber die Metamorphose der
Echinodermen. Jéid., Heft v.

1850. D’OrBteny. ALCIDE..........:..:. Prodrome de Paléontologie. 3 vols. 12mo.

Basie Description des Fossiles du groupe Nummulitique des environs de
Dax et de Bayonne. Bull., 2e série, vol. iv, p. 1006, 1847;
Mém. de la Soc. Géol. de France, 2e série, vol. iii, p. 397,

1850.
RGD Os DELLARDE. Lass .scavesivaiiiescdsen Liste des Fossiles de la formation Nummulitique du comté de Nice.
*Bull.,’ 2e série, vol. vii, seance 17 Juin, 1850.
RGD VOGTO Tek castor ens conto hse Zoologische Briefe Naturgeschichte. 2 Band 8vo, fig. Frankfurt.
1851. Correav. GUSTAVE ............... Catalogue Méthod. des Echinides Néocomiens. ‘Bull. Soc. des

Sc. Nat. de l’'Yonne,’ t. v, p, 285.
seh Lo See ane re Ueber die Ophiuren-larven des Adriatischen Meeres. ‘Miiller’s
Archiv,’ Heft i, 1851.
1851. Huxiry. Tuos. H. ............... Report upon the Researches of Professor Miiller into the Anatomy
and Development of the Echinoderms. ‘Ann. and Mag. of
Nat. Hist.,’ 2d series, vol. viii, p. 1.

1851. Mutinr. Jonann

1851. Gray. JoHN Epwarb ............ Description of some new genera and species of Spantangide in the
British Museum. ‘Ann. and Mag. N. H.,’ 1851, vol. vii.

58

AA8 BIBLIOGRAPHY OF THE ECHINODERMATA,

1851. Gray. Joun EDWARD ...

1851. WriegHt. THoMAS ......

.........Catalogue of Echinidee, or Sea-eggs, in the collection of the British
Museum. Part I, Echinida irregularia. 12mo, 1851.

On the Ciparip# of the Oolites, with a description of some new
Species of that Family. ‘Ann. and Mag. of Nat. Hist.,? 2d
series, vol. vill, p. 241.

1851. BS id | SVE EO Ae: ots SS On the Cass1DULID# of the Oolites, with descriptions of some new
Species of that Family. ‘Ann. and Mag. of Nat. Hist.,’ 2d
series, vol. ix, p. 81.

UGH. SLOONBKEINMUDID, 25 oncoasesenaano: 09 ou Statistique Géologique. Mineral. et paleontologique du departement

1852. QuENsTEDT. Fr. Ave...
1852. Wricut. THOMAS .....

1853. MULLER. JOHANN........

1853-55. D’OrBieny. ALCIDE

1854. Dre Koninck et Ln Hon

1854. Huxtny. Tuos. H. .....

1854. Stromprecx. A. Von ...

1854-58. Pictrt et RENEVIER

IGS, (Cnsots dls 185) cogoacnoaccaens

1855. Wricut. THoMAS ......

1855. Peters. WILHELM .....

1855. Corrnau. G...............

1855. Tuomny and HoLmzEs ..

1855. Wricut. THomas ......

dela Meuse. Paris, 1 vol. 8yvo, atlas folio.

bere heaie Handbuch der Petrefaktenkunde. 8vo, plates.
I: Contributions to the Paleontology of the Isle of Wight. ‘Ann. and

Mag. of Nat. Hist.,’ 2d series, vol. x, p. 87.
pt. Contributions to the Paleontology of Gloucestershire. A de-
scription and figures of some new species of Echinodermata from
the Lias and Oolites. ‘Ann. and Mag. of Nat. Hist.,’ 2d series,
vol. xiii, p. 161. :
Ueber den Bau der Echinodermen. ‘Vorgetragen in der Konigl.
Akademie der Wissenschaften zu Berlin.’ Plates.
Paléontologie Francaise. Terrains Crétacés, tome Sixiéme, contenant
les Echinodermes. Plates, 8vo.
Recherches sur les Crinoides du Terrain Carbonifére de la Belgique,
suivis d’une notice sur le genre Woodocrinus. Brux., 4to,

plates.

Pe On the Structure of the Echinoderms. By Johann Miiller, translated

by Thomas Huxley, F.R.S. ‘Ann. and Mag. of Nat. Hist.,’
2d series, vol. xiii, pp. 1, 112, 241; 1854.

On the Echinodermata of the Hilo-conglomerate in north-western
Germany. ‘Quart. Jour. of the Geol. Soc.; Geol. Memoirs,’
pels vol-ats

eae Fossiles de Terrain Aptien de la Perte du Rhéne. 4to, plates.

rosea Catalogue of the recent Echinide, or Sea-eggs, in the Collection of
the British Museum. Part I, Echinida irregularia.’ 12mo, with
plates.

On Fossil Echinoderms from the Island of Malta, with notes on the
stratigraphical distribution of the Fossil Organisms in the Maltese
beds. ‘Ann. and Mag. of Nat. Hist.,’ 2d series, vol. xv, plates vii.

Ueber die au der Kiiste von Mossambique beobachteten Seeigel,
und inbesondere tiber die Gruppe der Diademin. ‘ Vertrag.
Konig]. Akademie Wissenschaften zu Berlin,’ 1853, plate.

Note sur un nouveau genre d’Echinide fossile, Genre Desoredla.
‘Bull.,’ 2e sér., t. xii, p. 710.

see Fossils of South Carolina, Echinidze, 4to, plates.

On a new genus of Fossil Crparip®, with a Synopsis of the species
included therein. ‘Ann. and Mag. of Nat. Hist.,’ 2d series,
vol. xvi, p. 96.

On some new species of Hemipedina from the Oolites. ‘Ann.
and Mag. of Nat. Hist.,’ 2d series, vol. xvi, p. 98.

here wennee

1855

ARRANGED IN CHRONOLOGICAL ORDER. 449

-60. Wrienr. THOMAS ............

PODESORa Danes aad. ee eee:

SRHTAUET ONS VDa A y= ioe. lus c et

Monograph on the British Fossil Echinodermata from the Oolitic
Formations. Published by the Palwontographical Society of
London. Vol. i, 4to. The Echinoidea, with 44 plates.

Classification des Cidarides. ‘Bullet. de la Soc. des Sciences
Naturelles de Neuchatel,’ tom. iv, 8vo, plate.

Catalogue des Echinides Fossiles des Pyrénées. ‘Bull. de la Soc.
Géol. de France,’ t. xiii, p. 319.

Sur quelques Oursins du département de la Sarthe. ‘Bull. de la
Soc. Géol. de France,’ t. xiii, p. 646.

Memoirs of the Geological Survey of the United Kingdom.
Figures and descriptions illustrative of British organic remains.
Decade V. Echinide.

1857 Esquisse d’une description Géologique du Haut-Jura. Paris, Svo.

1857. Corrnau et TRIGER...............Echinides du département de la Sarthe. Liv. 1—5, with beautiful
plates.

RGIS Oe COVTEAU. Gil foes. saece a8 Echinides nouveaux ou peu connus. ‘Revue et Mag. de Zoologie,’
No. 5, Paris.

1858. Rent RES fyi hi oss Note sur l'appareil apicial du Genre Goniopygus. ‘ Bull. Soc. Geol.
Fr.,’ t. xvi, p. 162.

HSS. Eraunon: M.A. ....c0.060.8-.00 8 Etudes Paléontologiques sur le Haut-Jura Rayonnés du Corallien.
Ext. des ‘Mém. de la Soc. d’Emulation du départ. du Doubs,’
séance Mai 8, 1858.

RSS ENB IDA Vice Wt Elite ees deetse asians o's Etudes Paléontologiques sur le départ. de la Niévre; famille des
CoLLYRITIDE.

1858. QuENSTEDT. Fr. AUG............. Der Jura. 8vo, plates, Tiibingen.

1858-59. Brttines and SALTER ......

Geological Survey of Canada. Figures and descriptions of Canadian
organic remains. Decade III. Cystiprm and AsTERIDEA, by E.
Billings. Genus Cyclocystoides, by EB. Billings and J. W. Salter.
Decade IV. Crino1pr# from the Lower Silurian, by E. Billings.

1859. MicHeLin. Harpovtn............ Notice descriptive de quelques espéces nouvelles d’ Echinides,
famille des Clypéastroides, tribu des Laganides. ‘Revue et
Mag. de Zoologie,’ No. 9, 1859.

MGS Ge COREA. | Gece es ieaalene alee Note sur le Genre Galeropygus. ‘Bull. de la Soc. Géol. de Fr.,’
t. xvi, p. 289, Paris.

1859. Pe MND Set ee Sis Saya Notice Bibliographique. Synopsis des Echinides Fossiles, par Ed.
Desor. ‘ Revue et Mag. de Zoologie,’ No. 2, Paris.

1860. Re Mee cased oN ce as ase Note sur le genre Heterocidaris, nouveau type de la famille des
Cidaridées. ‘Bull. dela Soc. Géol de France, 2e série, t. xvii,
p- 378.

1860. BARN MURS Pose gree de os Saandnk 5 o Note sur les Echinides recueillis en Espagne par MM. de Verneuil,
Triger, et Collomb. ‘Bull. dela Soc. Géol. de France,’ 2e série,
t. xvi, p. 372.

1860. MicneLin. Harpoutn............ Monograph on the genus Clypeaster, with figures of all the species,

Living and Fossil. Folio, plates. As this work is not yet pub-
lished, I am unable to give its correct title. The author has kindly
sent me some of its magnificent plates.

sesheiarts ath.
ia’

1850.

1860.

. Hepert, Ep.

. WINKLER, J. J.

APD yt Tst.O.N AE

PRP ECOGKAEY OF THE

Forspes, EDWARD ...... ..

SSNORLGNUDM Sooo ae ohn caine gdnos

3)

. D’Arcurac et HaIMe.........
. ROLLE, FREDERICH.......

5, Lihobsaiaa gy MNSIOWU AS oaanecoeaaen:
. Correau et LEYMERIR.........

Mariel: Wes wesek.

5 dubai, (OAaNG0I) Cooonconer

| ABD ATS GUNNEOS Lecconsandoane

A COQUAND!.\--eeter nee ena

Corrzau, G.

N/Of Tee: S

ON THE

ECHINODERMATA.

“ Description of Fossil Echinidz from Portugal.” ‘Quart. Jour. Geol.
Soc.,’ vol. vi, p. 195, pl. xxv.

**Oursins Fossiles du départment del’Eure.” 8vo.

*“Note on Eocene Echinoderms procured by Sir Charles Lyell in
Belgium.” ‘Quart. Jour. Geol. Soc.,’ vol. viii, p, 340, pl. vi.

‘Monograph of the Echinodermata of the British Tertiaries. Paleeon-
tographical Society, vol. 1852.

‘Description des Animaux Fossiles du Groupe Nummulitique de |’ Inde.’

“Die Echinoiden der oberen Jura-Schichten von Nikolsburg in
Mahren.”’ ‘Sitzungs-berichte der Akad. der Wissenschaften,’
Vienna, B. xv, p. 521.

“Lectures on the Structure of tne Echinodermata.’
‘Medical Times.’

“ Catalogue des Hchinides Fossiles de Pyrenées.’’ ‘ Bull. de Soc. Géol.
de France,’ 2e série, t. xiii, p. 319.

On some New Paleozoic Star-fishes.”’
Hist.,’ 2d series, vol. xx, pl. ix.

‘‘Les Mers anciennes et leur ravages dans le bassin de Paris Terrain

London,

‘Ann. and Mag. of Nat.

Jurassique.” 8vo.
“« Ueber neue fossile Stelleriden.”’ ‘Sitzungs-berichte K. Akad. Wissens-
chaft.,’ Vienna, Bd. xxviii, p. 155.
‘Geological Survey of the State of Iowa,’ 2 vols. 4to, 1 vol. of
beautiful plates.
‘Die Schichten der
Alpen.’ 8vo, pl., Miinchen.
“‘Synops. des fossiles de la formation Cretacée du Sud-ouest de la
‘Bull. Soc. Géol. de France,’ 3e série, t. xvi, p. 1013.
‘Bull.

Avicula contorta inner-und ausserhalb der

France.”
“Sur le genre Metaporhinus et la famille des Collyritides.”’
Soc. Hist. et Naturelles,’ Yonne.

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45]

ADDITIONAL NOTES ON THE ECHINOIDEA.

Since the commencement of this Monograph in 1855, I have obtained additional
information on many of the species described therein, and have lately discovered some
new forms. I purpose, therefore, giving notes on the described species under their
respective names, and in the same order as they were originally figured in the body of
the work. The descriptions of the new species which are lithographed in the supplementary
plates will be found among the genera to which they belong.

CIDARID A.

\

Ciparis Fowuert, Wright. Supplement, Pl. XLII, fig. 1, a, 4, ¢, d, e, f.

The fine specimen figured in this plate was found in a mass of pea-grit on Leckhamp-
ton Hill; the block containing the urchin had been long exposed to the atmosphere, and the
test, In consequence, is a little weathered in parts. It has seven primary spines, more
or less perfect, with several secondary spines attached zu sctu to the test. The primary
spines (P]. XLII, fig. 1 e) are long, slender, and nearly of a uniform diameter through-
out, apparently tapering very little towards their free extremity. The head is strongly
crenulated, the milled rim prominent, the neck smooth and of the same thickness
as the body; the surface of the long stem is covered with short, thorn-like tubercles,
which have their points directed forwards. As ‘all the spines are more or less fractured,
their proportionate length to the diameter of the test cannot be ascertained. The secondary
spines (fig. 1 f) are small and spatulate; many of them are still adherent to the
plates of the test. Fig. 1 6 represents an inter-ambulacral plate, with its primary tubercle
and circle of areolar granules ; fig. 1 c, a profile of one of the large tubercles, showing
the prominence of the crenulations; fig. 1d, one of the jaws of the lantern, magnified

twice.

Ciparis Smirau, Wright. Supplement to pages 50—52.

When I figured the very fine specimens of Pl. II, considerable doubts existed relative

to the locality whence they were collected. My lamented colleague, Professor Forbes,
59

A52 ADDITIONAL NOTES

was impressed with the idea that they were foreign fossils, and was averse to their being

drawn as British Echinide ; the history of the specimens, however, convinced me that they
were English, although their locality was then unknown. Some time after the publication

of the first part of this work, J went to Oxford for the purpose of examining the late Dr.

Buckland’s collection, and in one of the drawers of his cabinet I saw a Cidaris Smithit,

from the same rock as that in which my doubtful specimens were imbedded. I lost

no time in visiting the locality, Bullington Green, near Oxford, whence it was ob-

tained, where J found several plates of tests and fragments of spines of the species.

From this locality Mr. Whiteaves, of Oxford, lately collected a very large specimen of
Cidaris Smith, which, through that gentleman’s kindness, is now in my cabinet. This

test measures three inches and three quarters in diameter, one third more than the

largest specimen previously known, and has the jaws and teeth zz situ. In the same

stratum of Coral Rag at Bullington, I found Achinobrissus scutatus, Lamk., Pygaster

umbrella, Agas., and Pygurus pentagonalis, Phil. I have lately obtained Cidaris Smithat,

Wr., from the Coral Rag at Hillmarton, Wilts, where it is associated with Cidaris flori-

gemma, Phil., Pseudodiadema versipora, Woodward, and Pygaster umbrella, Agass. This

is the original locality whence Dr. William Smith obtained the specimen now in the British

Museum.

Dietociparis Wricutil, Desor. Pl. XLI, fig. 6, 7, Supplement to page 58.

A very fine, large specimen of this gigantic Cidaris was discovered by my friend, the
Rev. 'T. W. Norwood, in the Inferior Oolite at Shurdington Hill, near Cheltenham.
Unfortunately, I have only been able to figure one of its largest spines. This was
undoubtedly, one of our largest Oolitic Cidaridze, and, from Mr. Norwood’s description, must
have attained a gigantic size, as appears by the following note, which that gentleman
has kindly supphed.

“The urchin, of which I sent you the fragments about a year ago, was found by me
in the Pisolite of Shurdington Hill, under the following circumstances. A very thin,
sandy, band divided two compact and indurated rock-masses forming a plane of
easy and natural separation between them. In this band the urchin had been
locked up, apparently in a state of wonderful preservation, and in the posture of life, with
its equator evenly parallel to the divisional plane of the strata, and its magnificent spies
(such as I have nowhere else seen) radiating regularly around it. The ground had chanced
to be broken at this point for the purpose of quarrying stone for wall-making; the upper
rock-bed had been removed down to the sandy band; and, in its removal, had torn
the urchin in two at the equator, and carried away half tke test and a corresponding
number of spines. Therefore, when I came to the place and discovered the specimen, it
was lying on the surface of the lower rock-bed, showing five or six large spines, which
appeared to diverge from a circular space, about equal in diameter to the equatorial

ON THE ECHINOIDEA. . 458

section of Cidaris Fowlert or C. florigemma. On tlie spur of the moment and with insuf-
ficient tools I rashly attempted to detach my treasure; and as it turned ont that the
lower portion of the test was fast imbedded in the hard rock beneath, I had the sad
mortification to fracture and destroy it. As I soon afterwards handed over to you the
fragments that remained, I now leave the description of them in your hands. This urchin
was associated, in the same rock-surface, with Pyyaster semisulcatus, Terebratula simplea,
and other equally characteristic fossils of the Cheltenham Pisolite.”

Hemicrparis Brintensis, Wright, nov. sp. Supplement, Pl. XLIII, fig. 2 a, 4, ¢, d.

Test sub-globose, ambulacral areas wide, with two rows of primary tubercles, which
extend over three fourths of the area; inter-ambulacral areas narrow, with two rows of
small, nearly equal-sized, tubercles, ten in each row; apical disc large, plates very narrow,
in consequence of the wideness of the vent ; mouth-opening large, peristome divided into ten
nearly equal lobes ; poriferous zones narrow and much undulated ; pores very much crowded
at the base.

Dimensions.—Height, one inch ; transverse diameter, one inch and a half.

Description.—This remarkable urchin, at first glance, resembles an Acrocidaris, from
the size, number, and development of the tubercles on the ambulacral areas. In most of
the other forms of Hemicidaris the semi-tubercles are limited to the basal region of the
ambulacra, but in this species they extend through nearly three fourths of the area; this
region of the test is likewise much wider than in other congeneric forms, in which the
semi-tubercles are limited to the base of the area, and the margins thereof are occupied
by rows of small granules. There are about ten tubercles, very regularly arranged, in each
row; those at the base are very small, whilst the upper six pair are nearly of a uniform
size, although rather smaller than the primary tubercles of the inter-ambulacra; the
upper part of the area has only a few, small granules on its margin. The poriferous zones
are very narrow, and extremely flexuous, winding round the border of the large semi-
tubercles, and only becoming straight at the upper fourth, where they cease (fig. 2 c).
The pores are separated by a thick septum, and there are six pairs of holes opposite each
inter-ambulacral plate; they are much crowded together, in oblique rows, in the wide
spaces left by the small semi-tubercles at the base of the areas.

The inter-ambulacral areas are narrow, scarcely twice the width of the ambulacra;
they are occupied by two rows of primary tubercles, about ten in each row, of a
moderate size, and nearly uniform magnitude throughout (figs. 2 a, 4); they are
raised. on prominent bosses, with deeply crenulated summits (fig. 2 ¢); the areolas are
transversely oblong, and confluent above and below; a double row of small granules

454 ; ADDITIONAL NOTES

descends in a zigzag line down the middle of the area, and the zonal border of the plates
has a single row of the same sized granules, which separates the areolas from the poriferous
zones, and forms a series of crescents throughout the area (fig. 2 c).

The apical disc is large (fig. 2 a), and placed rather behind the vertex of the test;
the ovarial plates are narrow (fig. 2 d), and the duct-holes perforated near the apices
of the plates; the madreporiform body occupies, as usual, the right antero-lateral plate,
which is the largest; the three anterior ocular plates rest upon the ovarial plates, with
which they alternate, whilst the two posterior oculars are placed between the two postero-
lateral and single ovarial plates (fig. 2 d) ; the vent-opening is very large.

The base is flat, and the mouth-opening wide; the peristome is divided into ten
nearly equal-sized lobes; all the tubercles in this region are small, and the poriferous zones
at the base of the ambulacral areas are very much crowded, the pores being arranged in
oblique rows.

Affinities and differences.—This species differs so much in its general physiognomy from
the typical forms of its congeners that it requires a careful examination to be satisfied that
it is a Hemicidaris, the size and number of the semi-tubercles, extending as they do so
high up the area, and the small and uniform magnitude of the primary tubercles, produce
so many rows of tubercles on the flanks of this urchin (fig. 2 6, d@), that it might readily
be referred to the genus Acrocidaris rather than to the group to which it belongs. In
Acrocidaris, however, the tubercles are very unequal in magnitude on the sides of the test,
and each ovarial plate supports on its centre a small, primary, perforated and crenulated
tubercle, a character which is quite diagnostic of this genus. The greater width of the
ambulacra, and the presence of a double row of semi-tubercles, extending three parts
up the sides, distinguish this species from its congeners; the smallness of the primary
tubercles in the inter-ambulacra, and the increased number and nearly uniform size of the
same throughout the rows, distingujsh it likewise from Hemicidaris Davidsoni, Wr., another
Portland species, with which it has many affinities.

Locality and Stratigraphical position—This urchin was discovered in the Portland
Oolite, at Brill, and was purchased from the person who collected it therefrom by my
friend, the Rev. P. B. Brodie, who kindly communicated the specimen for this work; the
test is rather distorted, and much concealed by a small, encrusting oyster. At the same
locality my friend collected the large Hehinobrissus Brodie, Wr., of which I have givena
figure of the natural size in Pl. XLIII, fig. 3.

ON THE ECHINOIDEA. AD:

Or

DIADEMAD/i.
Genus—HETEROCIDARIS, Cotteau, 1860.*

Test large, circular, depressed, inflated at the sides, sub-convex above, almost flat
below ; the inter-ambulacral areas very wide, and provided with from six to eight rows of
large, nearly equal-sized, perforated tubercles, raised on prominent bosses, with crenulated
summits; the areola are narrow, and their circumference surrounded by a circle of
small, equidistant granules, a few only of which are distributed on the intermediate surface
of the plates.

The ambulacral areas are straight, very narrow, and slightly flexuous above; they are
furnished with two rows of small, distinct, perforated tubercles, uniform in size, and
raised on small bosses, which are placed in regular rows on the margin of the area; three
tubercles occupying the depth of each inter-ambulacral plate.

The poriferous zones are narrow; the pores are small, simple, non-conjugate, and
superimposed, having a slight disposition to a trigeminal arrangement near the mouth.

The mouth-opening is large and pentagonal, about one third the diameter of the test ;
from the narrowness of the ambulacra, the lobes of this portion of the peristome are
much smaller than those of the inter-ambulacra.

The spines are long and cylindrical; their surface is covered with fine, longitudinal
lines, having small, indistinct tubercles interspersed amongst them.

I refer this genus to the family Draprmapa, as I have defined it.t The size of the
test, the narrowness of the ambulacra, the width of the inter-ambulacra, and the numerous
rows of primary tubercles thereon, indicate that Hederocidaris has certain affinities with
Astropyga, although it possesses many characters by which it is readily distinguished from
that genus. Heterocidaris resembles some of the large forms of Memipedina, as
H. Marchamensis, Wr., but the deep crenulations on all the bosses shows it to be distinct
from that form. M. Cotteau observes,t that the genus Heterocidaris, notwithstanding its
resemblance to the Drapumapa, is separated from that family by a character of the
first order, namely, the structure of the peristome, which is pentagonal, and furnished
with ambulacral lips much more narrow than those which correspond to the inter-
ambulacra, whilst in the Drappmap# the peristome is always decagonal, and notched
by ten incisions more or less deep. He therefore places this genus in the family
Ciparip# of Desor, which forms, according to that author, however, a much larger
group than the family Ciparip of this Monograph.§

* Extrait du ‘ Bulletin de la Société Géologique de France,’ 2me série, tom. xvii, p. 378, pl. iv.
t+ See p. 18 of this Monograph.

t Extrait du ‘Bulletin de la Société Géologique de France,’ 2me série, tom. xvii, p. 380, pl. iv.
§ See p. 18.

456 ADDITIONAL NOTES

Heterociparis Wickrnse, Wright, nov. sp. Supplement, Pl. XLIII, fig. 5 a, 4, ec.

The only portions of this urchin I have seen were some fragments I found in the
collection of my friend, Mr. Leckenby, of Scarborough, and which were collected from a
sandy bed of Inferior Oolite at Blue Wick, near Robin Hood’s Bay, on the Yorkshire
coast. The fragment figured consists of four plates (fig. 5 a), representing one half of
an inter-ambulacral area. There are three rows of large, equal-sized tubercles on
each plate, which are perforated ; the bosses are prominent, and their summits deeply
crenulated (fig. 5 c); the narrow areola are surrounded by a circle of small granules;
other granules are likewise sparsely scattered over the intermediate surface of the plates.
This is the urchin which Professor Phillips refers to in his work on ‘The Geology of
Yorkshire, of which he figures a single tubercle (pl. xi, fig. 2), and catalogues, at page
155d, as a Cidaris from the Dogger of Blue Wick.

The only Heterocidaris known to M. Cotteau was obtained by M. Triger from the
Inferior Oolite of Chevain (Sarthe). This magnificent specimen (Heterocidaris Trigeri,
Cot.) has been figured in the ‘ Bulletin de la Société Géologique de France,’ 2me série,
t. xvi, p. 378, pl. iv, and likewise in the ‘Fchinides du département de la Sarthe,’
pl lvi. M. Babeau has collected a fragment of another test from the Inferior Oolite of
the environs of the Langres (Haute-Marne), from a rock which contained Cidaris spinosa
and C. Courtandina.

PsEUDODIADEMA LOBATUM, Wright, nov. sp. Pl. XLI, fig. 3 a, 6, Supplement.

Test depressed; ambulacral areas narrow ; inter-ambulacra wide, with two prominent
rows of primary tubercles; spies long, smooth, and pin-shaped; neck, ring, and head
covered with fine, longitudinal lines ; stem smooth and uniform in thickness, tapering only

near the point.
Dimensions.—\ndeterminate.

Description.—This small urchin was found at Pinhay Bay, near Lyme Regis, in a
thin band of marl appertaining to the zone of Ammonites planorbis. All the specimens
I have hitherto seen are so imperfect that they are isufficient for drawing up
a complete diagnosis of the species.

The ambulacral areas are narrow, but as all the specimens I have seen are unfortunately
fractured through this region, the number and size of the tubercles thereon cannot be
examined.

The inter-ambulacral areas are wide and well-developed, possessing two rows of
large, primary, perforated tubercles, raised on prominent bosses, with deeply crenulated
summits; they are surrounded by wide areolas, bounded by a defined margin, and
encircled with microscopic tubercles, which impart an ornamented character to the test.

ON THE ECHINOIDEA. 457

The spines are long and slender, the head is stout, the margin of the acetabulum
deeply crenulated (fig. 3 6); the milled ring prominent, the neck short, and both are
sculptured with fine, longitudinal lines; the long, slender stem is nearly of the same
thickness throughout, tapering to a point near the extremity. The proportionate length
of the spine to the diameter of the test cannot be ascertained, for, although entire
individual spines are abundant in the marl, those attached to the test are nearly all
fractured.

Affinities and differences—As P. lobatum is the oldest representative of the genus
Pseudodiadema, in the Oolitic rocks, it is unfortunate, from the crushed state in which
the test is found, that a critical comparison cannot be made between this species and
its other Oolitic congeners. The very narrow ambulacra have few tubercles thereon, but
as all the tests I have examined are fractured across this part, the details of its structure
cannot be seen. ‘The affinities between this urchin and some of the depressed Acrosalenias
is considerable, and the length of the spines in proportion to the size of the test renders
that relation still more remarkable.

Locality and Stratigraphical position.—This urchin was recently discovered at Pinhay
Bay, near Lyme Regis, in a bed of mottled clay, on the shore at low-water mark ;
many tests were found together, with numerous long, slender spines strewed in abundance
amongst them ; some of the spines were attached to their respective tubercles, so that the
identity of the spines is satisfactorily proved. This bed of clay appertains to the lower
division of the Lower Lias, and may probably correspond to a similar urchin vein found
in Warwickshire and Gloucestershire, at the base of the zone of Ammonites planorlis.

Temirrpina Tomesit, Wright, nov. sp.

Hemipedina Tomesii, Wr. Hemipedina Tomesii, Wr.

458 ADDITIONAL NOTES

Test circular, depressed; ambulacral areas wide, with two rows of small tubercles on
the margin of the area, set moderately distant apart; poriferous zones narrow ; pairs
of pores superimposed in groups of threes; inter-ambulacral areas with two rows of
primary tubercles on the centre of the plates, and two rows of secondary tubercles
internal to the primaries, which extend from the base and sides above the equator;
areole wide, encircled by granules which likewise cover the surface of the plates. Spines
long, slender, and needle-shaped ; surface covered with fine, longitudinal lines.

Dimensions.—Height unknown ; transverse diameter, one inch and two tenths.

Description.—The specimens of this urchin hitherto found are so much crushed and
broken that it is impossible to make an accurate description of the species. The test
is circular and depressed ; the ambulacra are one third the width of the inter-ambulacra,
and provided with two rows of small tubercles, which occupy the margin of the area ;
they are placed at a distance equal to the diameter of their areole apart from each other,
and a delicate, zigzag line of small granules descends down the centre of the area;
the poriferous zones are narrow, and in their upper part the pairs of holes manifest
a disposition to a trigeminal arrangement, the inclination of the rows being upwards
and outwards, the reverse of the direction in the genus Pedina. ‘There are four
or five pairs of holes opposite one large plate. ‘The inter-ambulacral areas are three times
as wide as the ambulacra at the circumference; one complete row of primary tubercles
occupies the centre of the plates, and one incomplete row the inner portion thereof ;
the latter extend from the base and sides to two plates above the circumference. ‘The
ptimary tubercles at the equator-have prominent bosses, which diminish in size on the
upper surface ; the areolz are wide, smooth, well defined, and confluent above and below,
laterally they are bounded by semicircles of small granules ; at the zonal side of the plates
there are three or four rows of the same-sized granules, and they likewise form circles
around the incomplete rows on the centre of the area. The spines are slender and
needle-shaped ; the milled ring is prominent, and the surface of the stem covered with
well-marked, longitudinal lmes. All the specimens I have seen hie on their base on the
matrix, and in none of them is the apical disc preserved.

Affinities and differences.—This urchin is much larger than Hemipedina Bowerbankii,
Wr., which was collected from the same zone of the Lower Lias, near Lyme Regis.
It resembles Memipedina seriale, Leym. (Pl. IX, fig. 3 a), from the Lower Lias of
France, but the inner row of tubercles in the inter-ambulacra are more developed and have
a greater extension in that species.

Locality and Stratigraphical position—YVhis urchin was discovered by Mr. R. Tomes

ON THE ECHINOIDEA. 459

on a slab of Lower Lias, at Binton, in Warwickshire,* and in the White Lias at Stoney-
thorpe, in the same county. The rock at Binton which contained this urchin comes from
the base of the zone of Ammonites planorbis, and is known to the workmen as the
Guinea Bed. It contains the bones of Saurian reptiles, &c., with the shells of Avicula
longicostata, Stutch, Lima punctata, Sow., Ostrea liassica, Strick., and a small Coral.
It may be justly considered as one of the basement beds of the Lower Lias, and this
Hemipedina one of the earliest forms of the Diapemap in the Liassic rocks.

Pepina Suituit, Forbes. Supplement, Pl. XLI, fig. 2a, 6,¢; Pl. XLII, fig. 1 a, 6,¢, a.
See pages 176-178, ‘ Monograph.’

PSEUDOPEDINA NoDOTI. Cotteau, Revue et Magasin de Zoologie, No. 5, 1858, pl. ii,
figs. 4—7.

Since I figured the original specimen of this species (P]. XIII, fig. 2), which was
collected by Dr. William Smith from the Inferior Oolite at 'Tucking Mill, I have met with
two specimens from the Inferior Oolite, near Cheltenham; one from the Great Oolite
near Cirencester, and one from the Cornbrash at Islip, near Oxford. One of the Inferior
Oolite specimens was obtained from the Oolite marl near the Seven Springs, and is
figured in Pl. XLI, fig. 2. The inter-ambulacral areas are very wide, and the plates com-
posing them large; on the sides and upper surface there is only one row of primary
tubercles situated very near the poriferous zones (fig. 2 4), and all the inter-tubercular
space 1s covered with very small granules: ‘The ambulacral areas are narrow, and taper
much; the tubercles are few in number, very small, and sparsely distributed on the upper
part of the area, but are larger and more numerous below. ‘The proximity of the
primary tubercles to the poriferous zones, the narrowness of the ambulacra, and the
sparse distribution of tubercles thereon, with the wide space down the middle of the
inter-ambulacra, which is occupied entirely with small granules, produce a remarkable
physiognomy in this urchin.

The specimen from Oxfordshire was discovered by Mr. Whiteaves in the Cornbrash
at Islip, and was presented by him to the Oxford Museum. I have figured this beautiful
fossil in Pl. XIII, fig. 1; as it is much more depressed than the Inferior Oolite varieties,
although it evidently belongs to the same species; the base is flat, the mouth-cpening
large, and the peristome deeply divided by notches (fig. 1 4); the tubercles are much
more abundant at the base (fig. 1 4), a second row occupying the middle of the mter-am-

* The reader is referred for a detailed description of this section to the author’s memoir, ‘On the
Zone of Avicula contorta, and the Lower Lias in the South of England.’ “© Quart. Journ. of the Gecl.
Soc.,”’ vol. xvi, p. 394.

60

460 ADDITIONAL NOTES

bulacra in this region of the test; these, however, are limited to the base, for on the sides
(fig. 1 c) and upper surface (fig. 1 a) there is only a single row of tubercles; at the base
of the ambulacral areas the tubercles are larger, and the pores, closely packed together,
lie obliquely across the zone in groups of threes (fig. 1 d).

Stratigraphical distribution.—1 know this urchin from the Pea Grit and Oolite Marl,
zone of Ammonites Murchisone, Inferior Oolite, from Crickley Hill, and the Seven Springs,
near Cheltenham.

The specimen from the Great Oolite near Cirencester was almost entirely denuded of
its test, but the position of the tubercles near the poriferous zones served to identify the’
species. ‘This specimen was collected by Mr. Bravender, and kindly communicated for this
work.

The Cornbrash specimen is circular, and much more depressed than any of the other
varieties. It has enabled us to describe and figure correctly the entire external structure
of this singular form.

Dr. Smith’s specimen had a very marked pentagonal base, and although this character
is absent in most of the specimens I have examined, still I have found the pentagonal out-
line to characterise one specimen from the Pea Grit and one from the Oolite Marl.

M. Cotteau recognised the resemblance which exists between this urchin and Pedina
Bakeri, Wr., but the absence of a good figure of Pedina Smithi, Forbes, rendered it
impossible for that learned author to discover the identity of his Psewdopedina Nodoti with
Pedina Smithu. The excellent figures which I have now given will show that the French
and English forms belong to the same species. M. Cotteau found the specimen figured by
him in the Museum of Dijon; it was obtained from the Etage Bathonien, route de Fauge
(Cote-d’Or), where it is very rare.

SALENIAD At.

ACROSALENIA PusTULATA, Forbes. Supplemental to pages 242-245.

I amindebted to Frederick Bravender, Esq., for the following notes on the discovery, in
December, 1858, of a bed of marl in the Great Oolite near Cirencester, which contained
immense numbers of Acrosalenia pustulata. We remarks—‘‘ We have discovered an
extraordinary urchin-bed in a quarry near the town, but unfortunately the urchins are
nearly allof the same sort. They occur in a marly bed in the Great Oolite, about four inches
above the clay bed. I have now as many as 500 specimens, and might have got 1000
if I wanted them, as they were as thick as bees in a hive. If the bed extends any further,
‘which will be ascertained when the quarrymen proceed, any quantity might be obtained.

The following section will afford an idea of the relative position of this marly vein
with its Acrosolenia.

ON THE ECHINOIDEA. 46]

Section of the Urchin Quarry near Cirencester.

West Braprorpd CLAY REPRESENTATIVE, | Six feet.
| with Terebratula digona, Sow.
| |
2. | Great OoLirTE. Six feet.
Ee | t 2
3. Marty VEIN, with Acrosalenia pustulata, Forb. _ ‘Two inches.
4, Banp or Srone. | Four inches.
De Cuay Brp. | Two feet.
i
Gann} Great Oo.ite.

“The bed No. 3 is the one where the urchins Acrosalenia pustulata, Forbes,
occur. ‘The only other specimen of a different kind is Holectyyus depressus, Lamk.
The beds Nos. 2, 3, 4, and 5 have been called Forest Marble, which we do not approve
of, as bed No. 2 is as decidedly freestone as the bed No. 6.”

Thomas C. Brown, Esq., of Cirencester, has likewise kindly furnished me with the
follewing note on this remarkable urchin-bed. He says— In January, 1859, a great
number of the Acrosalenia pustulata were found at Cirencester in the Great Oolite, eight or
ten feet below the top of that stratum. A space of four or five yards square, two inches thick,
was filled with this urchin, about 1000 in every superficial yard. They were found one
upon another, about three deep, in a bed of white, marly clay. The tests were filled with
this clay, and were found in a high state of preservation, with their spines recumbent upon
them. It is presumed that this species is gregarious, and that a shoal of them were
choked in a stream of mud; that they fell down together with the mud upon the
Oolitic Rock then in course of formation, and were covered up with subsequent deposits of ©
Oolitic matter. This species is not numerous in this district. The tests vary in size and
shape, probably from a difference in age and sex, and there is great diversity in the form
and number of the plates forming the apical disc. After repeated washings of the clay in
water, fragments of the test were found, with broken spines of the larger and smaller ones ;
some of the latter are of a purple colour, many loose teeth, and one perfect set, together
with Oolitic grains, but scarcely any other fossil.”

462 ADDITIONAL NOTES

ACROSALENIA PARVA, Wright, nov. sp.

Ambulacral areas with two rows of small marginal tubercles; inter-ambulacral tubercles
large at the equator, and small on the upper and under surfaces; mouth opening wide,
indistinctly decagonal, spines long and hair-like.

Dimensions.—Transverse diameter of the largest test two lines; height unknown.

Description.—The ambulacral areas of this Acrosalenia are moderately wide with
two rows of small, perforated tubercles on the margims of the areas, a smaller
tubercle alternating with a larger one throughout the row. The poriferous zones are narrow,
and the holes large and distant from each other. The inter-ambulacral areas are wide,
the plates have a single row of primary tubercles near their zonal sides, the tubercles near
the equator are large, and raised on prominent bosses with crenulated summits ; the areole
are narrow, and confluent above and below, a semicircle of microscopic tubercles encircles
the boss on its zonal side, and a zig-zag line of tubercles occupies the middle of the area
which forms similar crescents on the sutural side of the areole ; all these microscopic
tubercles are perforated, a fact which can only be ascertained by the aid of a microscope
with a half-inch object glass. The crenulations on the summit of the large bosses, when
seen in profile with the microscope, resemble a circle of beads around that prominence.

The mouth-opening is wide, and indistinctly decagonal. The long, fine, and hair-hke
spines are scattered in profusion over the surface of the slab. When examined with a half-
inch*object glass, their surface is seen to be covered with sharp longitudinal lines, having
an indistinctly undulated edge.

Affinities and differences —This species differs from Acrosalenta minuta of the Lower
Lias in having the ambulacral areas much better defined, and the tubercles of the inter-
ambulacra larger and more prominent. Although a very small urchin, its generic
characters are well marked; in the general neatness of its test it resembles some of the
young forms of Acrosalenia spinosa, Ag., from the Cornbrash; this urchin affords another
of those examples, so numerous among the Hchmodermata, that the earliest forms of genera
are, in general, those in which the typical characters of the group are best developed.

Locality and Stratigraphical position—This small urchin was found by Mr. ‘Tomes,
who has kindly communicated it for description in the Lower Lias of Warwickshire, in
the zone of Ammonites obtusus, it was associated with Ammonites Birchii, Sow., and has
numerous small Gasteropoda and Conchifera imbedded with it on the same slab. It
is the oldest Acrosalenia that has yet been found in the Lower Lias.

ON THE ECHINOIDEA. 463

ECHINOCONID Zi.
Pyeastur sEMisuLcatus, Phillips. Pl. XLIII, fig. 6, Supplement to pages 273-78.

Professor Phillips found in the Inferior Oolite of Whitwell the original specimen of
Pygaster semisulcatus ; from the outline of the vent of that figure, it is still, however,
doubtful whether the urchin he figured in Pl. IIL, fig. 17, of his ‘Geology of Yorkshire,’
was a Whitwell specimen. I am of opinion that it was Pyvaster umbrella, Ag., from the
Coralline Oolite of Ayton or Hildenley that formed the type, and not a Whitwell specimen
at all. At that time, and for long afterwards, both urchins were considered to belong to
one species, and it is very probable that, as much finer specimens of Pygaster were
collected from the Coralline Oolite than had been obtained from Whitwell, a specimen
from the Coralline Oolite was preferred for the drawing. I have shown in my articles
on these two species how perfectly distinct Pygaster semisulcatus is from Pygaster umbrella,
and any one carefully comparing our description with Professor Phillips’s figure will at
once discover that the vent-opening in his drawing is the keyhole-shaped vent of
P. umbrella, and not the wide opening of P. semisulcatus.

Having lately found a very good specimen of the true Pygaster semisulcatus from the
Inferior Oolite of Whitwell in the collection of my friend, C. W. Strickland, Esq., of
Hildenley, I have figured a portion of the posterior view of this urchin, with the view
to exhibit the form of the vent-opening. It will be observed that this aperture is much
smaller than the vent-opening of P. semisulcatus from the Inferior Oolite of Glouces-
tershire (P]. XIX, fig. 1), and does not extend so far down the single inter-ambulacram
as in that specimen ; the tubercles are likewise more sparse upon the Yorkshire urchin,
aud the mouth-opening is relatively smaller. It is important to note these characters,
as they belong more to varieties of a given type than to a new specific form, and serve
to teach us that, before the history of a species can be fully written, it is necessary to
collect different individuals of the same species from localities widely apart,in order that
we may estimate the degree of variation which changes of physical conditions were
capable of exercising on the secondary characters of specific forms.

PycastER macrostoma, Wright. Supplement, Pl. XLI, fig. 4 a, 4, ¢; fig. 5 a, 6.

Test depressed, pentagonal; anal opening large, wide, occupying nearly two thirds
of the single inter-ambulacrum; sides tumid, base convex from the peristome to the
border, mouth-opening large, one fourth the diameter of the test.

464, ADDITIONAL NOTES

Dimensions.—Ueight, seven tenths of an inch; transverse and antero-posterior
diameters of the test nearly equal, two inches.

Description —This urchin is remarkable for the length and width of the anal aperture,
and for the great size of its mouth-opening ; it is likewise much depressed and _penta-
gonal, and covered with very small tubercles, sparsely distributed on the plates (fig. —
5 a); in these respects it presents an assemblage of characters which, taken together, pro-
duce a form very different to any of the many varieties of Pygaster semisulcatus which
have hitherto passed through my hands; for these reasons I have separated it from
them under a distinct name.. Knowing, however, the wide variations which many species
exhibit in different individuals, and how necessary it is to possess examples of a series
of these forms for comparison. I am most reluctant, in the absence of such materials, to
multiply specific names. Still, for the sake of clearness, the provisional name macrostoma
is proposed for this form.

Having only seen three or four examples of Pygaster macrostoma, the evidence, to my
mind, is not sufficient to write positively on the subject, although all these specimens were
remarkable for the great size of the two openings in the test.

Should a number of specimens of this urchin be hereafter gathered, and carefully
compared with each other, it will then be seen whether the characters I have pointed out are
persistent in the group, or shade off into forms, which may blend with other varieties
of Pygaster semisulcatus. In the mean time it is nght to register this urchin under a
provisional name, and wait for the future discovery of more specimens for determination.
The one proposed indicates its characters.

Part of the apical disc is preserved in a smaller specimen (fig. 5 4); it consists of
four ovarial plates, the right antero-lateral supporting the madreporiform body bemg the
largest, the single ovarial plate is absent in this specimen; the five small heart-shaped
ocular plates are wedged in the interspaces between the ovarials (fig. 5 6), forming a
crescent around the sub-compact disc; the posterior margin of the plates is free (fig. 5 4) ;
it does not appear, however, in what manner the anal membrane and plates were connected
therewith.

Locality and Stratigraphical position —This urchin was collected in a bed of sandy
Oolite, near Hampen, but whether it belongs to the Inferior Oolite or Cornbrash, I have,

at present, no means of determining.

ON THE ECHINOIDEA. 465

GALEROPYGUS AGARICIFORMIS, Forbes. Supplement, Pl. XLII, fig. 2 a and fig. 3,
pages 292-95.

GALEROPYGUS AGARICIFORMIS. Cotteau, Bulletin Soc. Géol. de France, 2me série, tom. xvi,
p- 289.

Although many hundreds of specimens of this urchin had passed through my hands
when I described the species, still I had not then seen any traces of the apical disc ; I was,
therefore, unable to give any opinion upon M. Cotteau’s proposal to separate into a dis-
tinct genus, under the name Galeropygus, those Hyboclypi which possessed a sub-compact
and not an elongated disc. Very lately, however, I met with two specimens of this
urchin which possessed portions of the disc 2” sttw, and these form the subjects of
figs. 2 and 3 of the Supplemental Pl. XLII.

The four ovarial plates, which are of a rhomboidal figure, are arranged in a crescentic
form around the concave, anterior opening of the round, discal aperture; the right antero-
lateral plate is the largest, and supports the madreporiform body; the plates are small,
and externally present acute angles, which are inserted into the Y-shaped notches of the
inter-ambulacral segments of the discal opening; the foramina for the ovarial tubes are
at the extreme point of the angle, andin some almost marginal. Four of the ocular plates
are very small, and intercalated between the angles of the ovarial plates; the left postero-
lateral is larger than the others, and wedged between the two left lateral ovarials, and all
the orbits are distinctly marginal (fig. 3). The posterior part of this singular structure is
absent, and it does not appear in what manner the single ovarial was articulated with the
others, nor how the membrane of the vent, with its anal plates, was united to the test.

M. Cotteau first proposed the separation of Hyboclypus disculus, Ag., into the
genus Galeropygus, from observing the difference which the disc of that urchin presented
when compared with the true type form of the genus, Hydoclypus grbberulus, Ag.

The apical discs of the HowinorpEa mxocycLica may be arranged, as M. Cotteau
observes, into three groups—Ist, compact ; 2d, sub-compact ; and 3d, elongated.

The disc is said to be compact when the ovarial plates form a circle around the madre-
poriform body, and when the five small ocular plates are intercalated between the angles
formed by the ovarial plates, as in Holectypus, Clypeus, Galerites, and Hchinoconus.

The disc is sb-compact when the three anterior ocular plates are intercalated between the
angles of the ovarial plates, whilst the two posterior ocular plates are longitudinally on the
same line as the postero-lateral ovarials ; sometimes the single plate is altogether wanting ;
but it is oftener represented by two or three small, complementary, imperforate pieces,
which reach the madreporiform body. This disposition of the plates gives the disc a
sub-circular form, such as is seen in Pyrina and Galeropygus.

466 ADDITIONAL NOTES

The disc 1s elongated when the four ocular plates, the anterior, lateral, and posterior, are
longitudinally on the same line with the ovarials. ‘The single ovarial plate is sometimes
absent, as in the sub-compact disc; it is oftener, however, represented by one or many
small, irregular, and imperforate complementary pieces, as in Hyboclypus and Collyrites.

The discs which I have discovered in Galeropygus agariciformis and G. caudatus
undoubtedly belong to the sub-compact group, and justifies M. Cotteau in removing
them into the genus he has established for their reception.*

ECHINOBRISSID A.

Cuyprus Puoru, Ave. P). XLII, fig. 4 a, 6, Supplement to page 364.

Previous to the publication of the figures and description of Clypeus Plotii in this
Monograph, no notice had been taken by former authors that the small tubercles of this
urchin were perforated; the specimen I figured was supposed by some to have been
exceptional rather than typical, as several accurate cbservers had failed to verify Mr. Bone’s
figures. Accordingly I exposed several specimens of Clypews Plotii on my garden-wall
during two winters, and effectually weathered the surface of their tests; by this process
I have ascertained, that all the tubercles on the inter-ambulacra, and likewise on the
ambulacra, including even the minute granules ranged on the edge of the zonal septa,
are perforated. I have in fig. 4 @ represented a portion of the upper surface of this
urchin, of the natural size, and in fig. 4 6 given a magnified view of one of the plates thereof ;
the bosses of the tubercles, with their deep-encircling areolz, and the perforation of the
summits, are well represented in this drawing, together with the miliary granules which are
freely scattered over the surface of the test. ‘The form and structure of the apical dise are
likewise well seen in fig. 4 a; the elements of this compact disc are covered by the
madreporiform body, which in this species extends over the surface of all the genital and
ocular plates, the only indication of these bodies being the five orbits at the summits of the
ambulacra and the four openings of the genital ducts opposite the inter-ambulacra; the
spongy structure of the madreporiform body is hkewise beautifully exemplified m_ this
weathered specimen.

* For ample details on the genus Galeropygus the reader is referred to M. Cotteau’s excellent memoir
on that new genus, in the ‘ Bulletin Soc. Géol. de France,’ 2me sc¢rie, t. xvi, p. 289.

— — ——

ON THE ECHINOIDEA. 467

ECHINOLAMPID/.

Pycurus Hausmannt, Koch and Dunker.

In all the specimens of this large
urchin hitherto found it is the upper
surface alone that is exposed. My
friend, W. C. Strickland, Esq., having
met with an uninjured test, he de-
termined to remove the matrix from
the base, with the intention of showing
the mouth- and vent-openings ; this he
has succeeded in doing, and I am
now, through his kindness, enabled to
give a figure of the under surface and
complete the description of this remark-
able species.

The base is concave, inclining on
all sides towards the mouth-opening,
which is nearly central, being only
three tenths of an inch nearer the
anterior border; the peristome is pen-
tagonal, and surrounded by five lobes,
which are moderately prominent; the
ambulacral valleys are slightly de-
pressed, and converge in straight lines
to the mouth ; the wide inter-ambulacra
are convex near the margin, and, with
the depressed ambulacra, present a

Pl. XXXIX, XL to Supplement, p. 405.

Pygurus Hausmann.

¥

m4
y
“
i

,
4
4
4
7
y
‘4
s
/

series of gentle undulations throughout the under surface ; the anterior border is rounded,
without any trace of anteal sulcus ; the anal-opening lies in a deep, oblong depression near
the posterior border ; the test is very thin, and the tubercles in this region are very small ;
the apical disc is well preserved, and is only two lines in diameter; the small ovarial plates
are closely soldered together, and covered by the madreporiform body which entirely
envelopes the disc, and appears like a central spongy button at the vertex; the four
oviductal holes are visible, and alone indicate the extent of the plates ; the ocular plates are
not visible, mere depressions only showing their position.

61

A68 ADDITIONAL NOTES.

This specimen was collected from the Coralline Oolite at Settrington, near Malton,
whence several good specimens have been obtained; the oolitic rock is here very fine,
and cuts almost as white as chalk. Coral banks are likewise very abundant in this locality,

and the fineness of the Oolite is probably due to the coralline mud which abounded in the
vicinity of these Anthozoa.

INDEX

TO THE

BRITISH FOSSIL ECHINODERMATA OF THE OOLITIC FORMATIONS.

VOLUME IL.—THE ECHINOIDEA.

PAGE
BIBLIOGRAPHY . : ; : ‘ : : 3 437—449
NOMENCLATURE . : : : é ; ; : . 1—8
STRATIGRAPHICAL DISTRIBUTION :—
Horizons—
Purbeck Cinder Bed ‘ , ; : ; : 98—100
Portland Oolite . s ; : ‘ 96—98 ; 353—355 ; 453—4.54
Kimmeridge Clay . : . 53; 166—168

Coralline Oolite . 44—52 ; 92—96 ; 100—101; 124—135; 161—166; 186—188; 215—219;
249—252; 267—268 ; 282—286; 303; 318—822; 346—353; 382—
385 ; 395—408 ; 451—452; 467—468

Cornbrash - 84—87; 118—122; 158—161; 173—176; 197—199; 208—210; 234—
240; 246—248; 260—264; 280—282; 309—318; 332—337; 341—
345 ; 361—366 ; 371—374; 392—394; 459—460

Forest Marble’. : : 234—238 ; 240—245; 248; 371—374; 392—394
Bradford Clay. . 42—43; 88—90: 112—114; 118—120; 242—245 ; 392-394
Great Oolite . 55; 78—87 ; 90—92; 112—114; 115—119; 123; 156—158; 173—176;

197—199 ; 213—215; 234—240; 242—245; 248—249; 275—278;
280—282; 292—298; 332—341; 261—366; 371—374; 392—394;
459—461

Stonesfield Slate . 4 : . 75—77; 114—115; 332—337; 361—366

Inferior oolite .32—42; 58; 71—75; 112—114; 149—156; 173—178; 191—193;
197—200 ; 204—213; 232—234; 238—240; 260—267; 275—280;
292—303; 309—318; 332—337; 361—371; 375—381; 392—394;
451—453 ; 456; 459—460; 463—464

Lias . , 26—32; 54—58; 110—112; 144—149 ; 230—232; 456—459; 462
Tabular view : : ‘ ; , : ; ‘ 413—435
TERMINOLOGY :—
Ambulacral and interambulacral areas F ; . : - SM
Apical disc . : : : : j ; : 5 ie
Poriferous zones : : é : : : 3 see?
Spines : : : : : ; : - ee
Test : A ; ‘ . : : : : 9
Tubercles . i ; f : : : ; 5 LS

62

A70) INDEX.

FAMILIES, GENERA, AND SPECIES.

The Synonyms are printed in Italics.

The letters F.S. following a species intimate that that form has not yet been found in the English Oolites.

PAGE
ACROSALENIA, Agassiz : 5 : : : ; : . 229
os aspera, Agassiz Ce : ; 3 : 5 . 249
2 Bouchardii, Desor (F.S.) ‘ ! : aR : Be AS}
PS erinifera, Wright ; see Acrosalenia minuta.
53 decorata, Haime : : : +e 5 : . 249
f elegans, Desor (F.S.) . : : 6 ; : . 254
5) granulata, Merian (I'.S.) : : : : . 254
i hemicidaroides, Wright : : : q : 234, 248
» Hunteri, Wright (E.8.) : : . : 6 | 257
5 interpunctata, Quenstedt (F.S.) . 0 . : ; 2a
6 Keenigii, Desmoulins (¥.S8.) , ; . : : . 256
55 levis, Agassiz ; see Acrosalenia spinosa.
Rs Lamarcku, Desor ; see Acrosalenia Wiltonii.
5 Lamarckii, Desmoulins (F.S.) . : : 5 : 5 BRS
. lens, Desor (F.S.) : . ‘ : : A . 255
I Loweana, Wright : 3 : ‘ ; : . 240
% Lycettii, Wright ; ‘ : 3 : 5 PB
% minuta, Buckman : : : : : : 5 0)
op parva, Wright : : : : 5 : - 462
55 pustulata, Forbes F : : : F : 242, 460
59 radians, Agassiz (F.S.) ; : : 3 ; - 255
ise radiata, Forbes : : ; ‘ . ; . 248
Pe radiata, Forbes; see Acrosalenia spinosa.
es rarispina, McCoy; see Hemicidaris minor.
3 spinosa, Agassiz 5 : ; 6 : . a) SKS}
5 Wilton, Wright : : : é . : . 246
_ Woodwardi, Wright (F.S.) : : ; ; : . 2om
Arbacia Forbesii, Wright ; see Magnotia Forbesii.
», hieroglyphica, Agassiz; see Glypticus hieroglyphica.
» Jurassica, Cotteau (F.S.) ; see Magnotia Jurassica.
», nodulosa, Goldfuss ; see Polycyphus Normannus.
ATROPYGA, Gray : : : : . : : 107, 108
ASTEROIDEA, Wright . ; F : : ; 3 + 135
BuastorpBA, Fleming ‘ é ; F ; : P SSHO
Crparipa, Wright ' : : ; 5 ; 18, 23, 107, 451
Ciparis, Klein . ; ‘ ‘ ; : “ 25, 107

» Amalthei, Quenstedt (F.S.) : : 4 : ; Sa)
», Bechei, Broderip; see Hemipedina Bechei.
» Blumenbachii, Goldfuss (F.S.) ; ; 5 0g

INDEX.

Ciparis, Boloniensis, Wright (F.S.) .

Bouchardii, Wright

Bradfordensis, Wright

confluens, Forbes ‘

coronata, Buckman ; see Cidaris Fowleri.

coronata, Goldfuss (F.S.) : :
crenularis, Lamarck ; see Hemicidaris Bravenderi.
diadema, Young and Bird; see Pseudodiadema hemisphericum.
Drogiaca, Cotteau (F.S8.)

Edwardsii, Wright ‘

elegans, Morris; see Cidaris Bouchardii.

elegans, Goldfuss (F.S.)

florigemma, Phillips -

Fowleri, Wright

gigantea, Agassiz (F.S.) ; see emtecidaris Rieainies
Ilminsterensis, Wright

intermedia ; see Hemicidaris intermedia.

Lorierii, Wright (F.S.)

marginata, Goldfuss (F.S.)

monilipora, Phillips ; see Pseudodiadema Hemrenharienn:
Moraldina, Cotteau; see Rabdocidaris Moraldina.
papillata, Parkinson ; see Hemicidaris intermedia.
Parandieri, Agassiz (F.S8.)

propinqua, Goldfuss (F.S.) .

Smithi, Wright .

spinosa, Agassiz .

Suevica, Desor (F.S8.) :

vagans, Phillips; see Pseudodiadema vagans.
Wrightii, Desor

Cidarites, Lamarck ; see Cidaride.

29

Blumenbachii, Goldfuss ; see Cidaris florigemma.
elongatus, Roemer ; see Cidaris florigemma.
Hofmanni, Roemer ; see Hemicidaris Hofmanni.
mamillanum, Roemer; see Pseudodiadema mamillanum.
maximus, Goldfuss ; see Rabdocidaris maxima.
nobilis, Goldfuss (F. S.) 2
pseudodiadema, Lamarck ; see Pseudodiadema Nemeonaticuin:

subangularis, Goldfuss (F.S.) ; see Pseudodiadema subangulare.

Clypeaster Blumenbachii, Koch and Dunker ; see Pygurus Blumenbachii.

2

”

Hausmanni, Koch and Dunker ; see Pygurus Hausmanni.
pentagonalis, Phillips ; see Pygurus pentagonalis.

CLYPEASTERIDD, Wright
Clypeopygus Hugit, Agassiz ; see Chypen Hugii.
CiyPeus, Klein . 5

bP)

7

Agassizii, Wright
altus, McCoy

471

PAGE
53, 64

65

360
378
366

A72

INDEX.

CLYPEUS angustiporus, Agassiz; see Clypeus Plotii.

Boblayi, Michelin (F.S.) .
clunicularis, Linwyd; see Echinobrissus clunicularis.
cordatus, Lang.; see Echinobrissus scutatus.
Davoustianus, Desor ; see Clypeus altus.

dimidiatus, Phillips ; see Echinobrissus dimidiatus.
emarginatus, Phillips; see Clypeus subulatus.
eacentricus, McCoy ; see Clypeus Plotii.

Hugi, Agassiz

lobatus, eke ; see Bonineheeens alamictanie
Michelini, Wright

Miulleri, Wright ‘ : :
orbicularis, Phillips ; see Echinobrissus orbicularis.
ornatus, Buckman ; see Pygaster semisulcatus.
Osterwaldi, Desor (F.S.)

patella, Lamarck ; see Clypeus loti.

Plotii, Klein

Rathieri, Cotteau (F.8.)

rimosus, Agassiz .

rostratus, Desor (F.S.)

semisulcatus, Phillips; see Pygaster semisulcatus.
sinuatus, Parkinson; see Clypeus Plotii.
Solodurinus, Agassiz (F.S.)

subulatus, Young and Bird .

°

Coma, Delue

analis, Desmoulins ; see Gislleeties ovalis,
bicordata, Leske

carinatus, Leske (F.S.)

capistrata, Goldfuss (F.S.)

castanea, Desor (F.S.)

censoriensis, Cotteau ; see Metaporhinus censoriensis.

Desoriana, Cotteau (F.S8.)
elliptica, Lamarck (F.S.)
excentrica, Goldfuss (¥.S.)
faba, Desor

Loryi, A. Gras (F.S8.)
Orbigniana, Cotteau (F.S8.)
ovalis, Leske

pinguis, Desor (F.S.)
ringens, Agassiz
transversa, d’ Orbigny (F. 8)
Voltzii, Agassiz (F.S.)

CoLLyRitipm, Wright
Crinoipna, Miller
CyYPHOSoMA, Agassiz
CysrorpBa, von Buch.

PAGE

386

375

369
371

387

361, 466
387
381
387

INDEX.

DiapEMA, Gray .

a eequale ; see Pseudodiadema homostigma.

re e@quale, Agassiz; see Pseudodiadema equale.

a affine, Agassiz ; see Pseudodiadema affine.

x Bakeria, Woodward ; see Pseudodiadema Bakeriz.

.s Bechei, Broderip; see Hemipedina Bechei.

- complanatum, Agassiz ; see Pseudodiadema complanatum.

* Davidsonii, Wright ; see Pseudodiadema mamillanum.

ae depressum ; see Pseudodiadema depressum.

a hemisphericum, Agassiz ; see Pseudodiadema hemisphericum.
Bs homostigma ; see Pseudodiadema homostigma.

a inequale, Agassiz; see Pseudediadema inzequale.

es Lamarckii, Desmoulins ; see Pseudodiadema hemisphericum.
‘3 mamillanum, Roemer ; see Pseudodiadema mamillanum.

c Mooreit, Wright ; see Pseudodiadema Mooreii.

= Orbignyanum, Cotteau ; see Pseudodiadema Orbignyanum.

a5 pentagonum ; see Pseudodiadema pentagonum

= placenta, Agassiz (F.S.) ; see Pseudodiadema placenta.

» pseudodiadema, Agassiz; see Pseudodiadema hemisphericum.

# spinososum, Agassiz; see Pseudodiadema mamillanum.

E subangulare ; see Pseudodiadema versipora.

5 superbum, Agassiz; see Pseudodiadema superbum.

3 tetragramma, Agassiz ; see Pseudodiadema tetragramma.
ts transversum, Agassiz; see Pseudodiadema hemisphericum.
a vagans ; see Pseudodiadema vagans.

= versipora; see Pseudodiadema versipora.

DiapemaDa, Wright :
Diademopsis Mooreii, Desor ; see Pseudodiadema Mooreii.

DipiocipARis, Desor : : : ;
“ Desori, Wright : : :
z gigantea, Agassiz (F.S.)
A Wrightii, Desor ; :

Diplopodia pentagona, McCoy ; see Pseudodiadema pentagonum.
c subangulare, Agassiz ; see Pseudodiadema versipora.

Disaster Agassizii, Wright ; see Collyrites ovalis.
» analis, Desmoulins ; see Collyrites ovalis.

», anasteroides, Leymerie (F.S.) : : :
a avellana, Agassiz ; see Collyrites ovalis.

3 bicordatus, Agassiz; see Collyrites ovalis.

ellipticus, Lamarck ; see Collyrites elliptica.

Eudesii, Agassiz ; see Collyrites ringens.

granulosus, Goldfuss (F,S.) 3 :
Moeschii, Desor (F.S.) : : F :
propinguus, Agassiz ; see Collyrites bicordata.

ringens, Agassiz; see Collyrites ringens.

Robinaldinus, Cotteau ; see Collyrites ovalis.

» symmetricus, McCoy ; see Collyrites ovalis.

18, 106, 108, 455

: ¢ 36
- hae

: 320

323
323

474 INDEX.

PaGE

Disaster Voltzvi, Agassiz; see Collyrites Voltzii.
Discoidea depressa, Leske ; see Holectypus depressus.

», hemispheriea, Agassiz; see Holectypus hemisphericus.

» mflata, Agassiz; see Holectypus inflatus.

», marginalis, McCoy ; see Holectypus hemispheericus.

», speciosa, Agassiz: see Holectypus giganteus.

», speciosa, Goldfuss: see Holectypus speciosus.

Echinanthites orbicularis, Young and Bird ; see Pygurus pentagonalis.
Ecuinipm, Wright ; F : bie ° 19, 183
Echinites depressus, Leske ; see Holesty ue denteesie
» elunicularis, Llhwyd ; see Echinobrissus clunicularis.
» ¢elypeatus, Lihwyd; see Clypeus Plotii.
cordatus, Lang. ; see Echinobrissus scutatus.
» sinuatus, Schlotheim ; see Clypeus Plotii.
», subulatus, Young and Bird; see Clypeus subulatus.
» toreumaticus, Leske ; see Glypticus hieroglyphicus.

ECHINOBRISSIDA, Wright . 0 : ‘ : : . 20, 330, 446
EcuHINOBRISSUS, Breynius . : ; : ; : . 331
Us amplus, Agassiz (F. s. ) A : ; : ‘ S57
PS Brodiei, Wright ‘ : 5 : : ‘ 5 BRS)
ae clunicularis, Lihwyd 2 : 5 ; E . 332
ss erepidula, Desor (F.S.) d é : : : . 356
a dimidiatus, Phillips . ‘ ; : : : - 350
na elatior, Breynius ; see Echinobrissus scutatus.
5 elongatus, Agassiz (F.S.) , ‘ : ; ; . 396
a Goldfussi, Desmoulins (F.S.)_ . : : : 3 5 Guts
5 gracilis, Agassiz (F.8.) f ; ; y Sse
i Griesbachii, Wright . : ; : é : . 340
eS Hugit, Agassiz; see Clypeus Hugii.
5 Icaunensis, Cotteau (F.S.) : : : : . 359
, latiporus, Agassiz; see Echinobrissus clunicularis.
6 major, Agassiz (F.S.) ; : ; : 3) 7
5 orbicularis, Phillips F ; : ; . 84)
% planior, Breynius ; see Echinobrissus clanieatanie’
) planulatus, Roemer (F.S8.) : : j : : . ood
5 pulvinatus, Cotteau (F.S.) : 6 : ; . 358
5 quadratus, Wright . : : ‘ . - 044
- Sarthasensis, d’Orbigny ; see isla ere clunicularis.
D9 scutatus, Lamarck . : : ‘ : : . 3846
y Tarquemi, Agassiz; see Echinobrissus clunicularis.
5 Thurmanni, Desor ; see Hchinobrissus clunicularis.
Rs truncatus, Desor (F.S.) ; : ; ‘ : 5 Shy
35 Woodwardii, Wright ‘ : : : ; = ood,
Echinoclypeus umbrella, Lamarck ; see Clypeus Plotii.
Eeutnoconipa, Wright . F ‘ ‘ : : ‘ 19, 258

Ecwinocoripa, Wright. ; : 5 : : : . 2i

INDEX.

EcnrinorpEa, Wright : : :
3 ENDOCYCLICA, Wright .
"5 ExocycLica, Wright

EcHINOLAMPIDA, Wright :
Echinolampas pentagonalis, Phillips; see yearns pentagonalis.
Ecutnonipa, Wright ;
Ecurnopsts, Agassiz : :
Pr Bechei, Baile see Hemipedina Bechei.
”
rotata, Forbes ; see Pedina rotata.
= Smithii, Forbes ; see Pedina Smithii.
EcuHINoTHRix, Peters , f . 5 :
Eehinus bigranularis, Lamarck ; see Stomechinus bigranularis.
» depressus, Leske ; see Holectypus depressus.
» depressus, Leske ; see Echinobrissus scutatus.
diademata, McCoy; see Stomechinus germinans.
‘discoides, Morton ; see Clypeus Plotii.

”

excavatus, Goldfuss ; see Stomechinus excavatus.
Forbesii, Wright ; see Magnotia Forbesii.
» germinans, Phillips ; see Stomechinus germinans.
», granularis, Wright ; see Stomechinus intermedius.
gyratus, Agassiz ; see Stomechinus gyratus.
hieroglyphicus, Goldfuss ; see Glypticus hieroglyphicus.
intermedius, Agassiz; see Stomechinus intermedius.
lineatus, Goldfuss ; see Stomechinus lineatus.
minutus, Buckman ; see Acrosalenia minuta.
», nodulosus, Morris ; see Polyeyphus Normannus.
nodulosus, Goldfuss ; see Magnotia nodulosa.
perlatus, Agassiz; see Stomechinus perlatus.
perlatus, var. Forbesii, Salter ; see Stomechinus bigranularis.
perlatus, var. germinans, Wright ; see Stomechinus germinans.
petallatus, McCoy ; see Stomechinus gyratus.
serialis, Agassiz ; see Stomechinus bigranularis.

» stnuatus, Linneus ; see Clypeus Plotii.

» sulcatus, Goldfuss ; see Glypticus sulcatus.
Lucosmus decoratus, Agassiz ; see Magnotia decorata.
Galerites depressus, Leske ; see Holectypus depressus.
hemisphericus, Agassiz ; see Holectypus hemisphericus.
patella, Lamarck ; see Clypeus Plotii.
radiatus, Valenciennes ; see Holectypus depressus.
speciosus, Goldfuss ; see Holectypus speciosus.
umbrella, Lamarck ; see Clypeus Plotii.
Galeropygus agariciformis, Forbes . :
GLYPTICUS, Agassiz
Burgundiacus, Michelin (F. 8.)
hieroglyphicus, Goldfuss .

27

ord

Nattheimensis, Quenstedt ; see Hemipedina Nattheimense.

475

PAGE

3, 4, 6, 9, 18
17, 18, 416
17, 18, 416
20, 389, 467

20
108

108

465
185
. 189
- 186

476

INDEX.

Giypticus sulcatus, Goldfuss (¥.S.) .

Goniopygus perforatus, Wright ; see Hemipedina Perfern

‘Grasia elongata, 4. Gras

HEMICcIDARIDA, Wright
HEMIcrIDaARIS, Agassiz

_ alpina, Agassiz (FS. yi

alpina, Agassiz ; see Hemicidaris Wrightii.
Bravenderi, Wright

Brillensis, Wright

confluens, McCoy

crenularis, Lamarck (F.S.)

Davidsoni, Wright

diademata, Agassiz (F.S8.)

granulosa, Wright

Hofmanni, Roemer (F.8.)

Icaunensis, Cotteau

intermedia, Fleming

Luciensis, d@’ Orbigny

minor, Agassiz

mitra, Agassiz

Purbeckensis, Forbes

pustulosa, Agassiz :

radians, Agassiz; see Acrosalenia radians.
Ramsay, Wright

Stokesii, Wright

stramonium, Agassiz (F.S.)

stramonium (McCoy), Agassiz; see Hem oder intermedia.

Thurmanni, Agassiz (F.S.)
Wrightii, Desor

Hemipepina, Wright

Bakeri, Wright

Bechei, Broderip

Bonei, Wright
Bouchardii, Wright (F.8.)
Bowerbanku, Wright
corallina, Wright
Cunningtoni, Wright
Davidsoni, Wright
Etheridgii, Wright
Jardinii, Wright
Marchamensis, Wright .
microgramma, Wright .
Morrisii, Wright
Nattheimense, Quenstedt (F.S.)
perforata, Wright
Semanni, Wright (F.S.)

PAGE
189

. 329
18, 68

104

453
102
103

104

108, 143
149
144
155
170
145
163
167
156
148
146
161
159
166
170
151
169

INDEX.

Hemipepina seriale, Leymerie (F.S.) .

FA tetragramma, Wright

5 Tomesii, Wright

a tuberculosa, Wright

A Waterhousei, Wright

a Woodwardi, Wright
Herrrocimaris, Cotteau

% Wickense, Wright

Ho.sctyeus, Desor

a arenatus, Desor (F'.S.)

corallinus, d@’ Orbigny (F.S.)

5 depressus, Leske :

fc Devauxianus, Cotteau; see Holectypus hemisphericus.

< giganteus, Desor (F.S8.) ; 3 e

3 hemispheericus, Agassiz .

a inflatus, dgassiz (F.S.) .

ss Mendelslohi, Desor (F.S.)

ra oblongus, Wright

5 planus, Desor (F.S.)

ii punctulatus, Desor (F.S.)

> speciosus, Goldfuss (F.S.)
HonotTnvuroipEa, Wright .
Hyxociyevs, Agassiz

i agariciformis, Forbes

53 cordatus, Wright 4 ‘

elongatus, A. Gras; see Grasia elongata.

$ gibberulus, Agassiz :

Rs Marcou, d’Orbigny ; see Hyboslypie ae
o ovalis, Wright
stellatus, Desor a : F
ipadiatona Etheridgii, Wright ; see Hemipedina Etheridgii.

Macgwnotta, Michelin

5 decorata, Agassiz (F.S. \.

i Forbesii, Wright

a Jurassica, Cotteau (F.S.) .

cp Nodoti, Michelin (F.S8.)

a nodulosa, Goldfuss (F.S.)
Metaporhinus censoriensis, Cotteau (F.S.)

55 Michelinii, Agassiz (F.S.)
Milnia decorata, Haime; see Acrosalenia decorata.

Nucleolites Agassizii, Wright ; see Clypeus Agassizii.
He altus, McCoy ; see Clypeus altus.
- amplus, Agassiz; see Echinobrissus amplus.
‘s celunicularis, Llhwyd ; see Echinobrissus clunicularis.
5 erepidula, Desor ; see Echinobrissus crepidula.

477

PAGE
169
152
457
164
154
158
455
456
259 ©
271
270
260

272
264
272
269
267
269
270
271
3, 4
291
292
296

298

301
303

190
195
191
194
194
194
328
328

478 INDEX.

Nucleolites decollatus, Quenstedt ; see Hyboclypus agariciformis.

is dimidiata, Desmoulins ; see Echinobrissus dimidiatus.
53 Edmundi, Cotteau; see Echinobrissus clunicularis.
- excentricus, Goldfuss ; see Collyrites excentrica.

ie excisus, Quenstedt ; see Hyboclypus gibberulus.

2 gracilis, Agassiz ; see Echinobrissus gracilis.

a5 granulosus, Goldfuss ; see Disaster granulosa.

5 Hugii, Agassiz ; see Clypeus Hugii.

55 latiporus, Agassiz; see Echinobrissus clunicularis.
a major, Agassiz; see Echinobrissus major.

5s Michelini, Wright ; see Clypeus Michelini.

. orbicularis, Phillips; see Echinobrissus orbicularis.
50 paraplesius, Agassiz; see Echinobrissus dimidiatus.
» patella, Lamarck; see Clypeus Plotii.

D planulatus, Roemer ; see Echinobrissus planulatus.
0 pyramidalis, M‘Coy ; see Echinobrissus clunicularis.
5 scutatus, Lamarck ; see Echinobrissus scutatus.

re semisulcata, Phillips; see Pygaster semisulcatus.

me Solodurinus, Agassiz; see Nucleolites Miller.

ay Sowerbyi, Defrance; see Echinobrissus clunicularis.
5 Terquemi, Agassiz; see Echinobrissus clunicularis.
a Thurmanni, Desor ; see Echinobrissus clunicularis.

ss Woodwardii, Wright ; see Echinobrissus Woodwardii.
OPHIUROIDEA, Wright

PEDINA, Agassiz . ;
arenata, Agassiz (F.S.)
» aspera, Cotteau (F.S.) é
rf Bakeri, Wright ; see Hemipedina Bakeri.
a Charmassei, Cotteau (F.S.) . :
e Etheridgit, Wright ; see Hemipedina Etheridgii.
oA Gervillii, Desmoulins (F.S.) .
5 Michelini, Cotteau (F.S.)
5 rotata, Wright
nS Smithii, Forbes
a subleevis, Agassiz (F'.S.)
Pileus hemisphericus, Desor ; see Pygaster pileus.

Polycyenus, Agassiz ‘ :
es Corallinus, Cotteau (F.S.)
9 Deslongchampsii, Wright
in distinctus, Agassiz (F.S.) .
Rs nodulosus, Goldfuss; see Polyeyphus Normannus.
0 Normannus, Desor
ee stellatus, Agassiz (F.S.)

PSEUDODIADEMA, Desor . é
y zquale, Agassiz (F.S.)

PAGE

+ 36

108, 171
179
181

181

179
180
173
176, 459
180

196
201
199
202

197
201
108
140

INDEX.

PsEUDODIADEMA afline, Agassiz (F.S.)

mm

Bailyi, Wright

Bakeriz, Woodward :
complanatum, Agassiz (F.S.) .
depressum, Agassiz .
hemispheericum, Agassiz
homostigma, Agassiz
ineequale, Agassiz (F.S.)
lobatum, Wright :
magnagramma, Wright (F.S.)
mamillanum, Roemer

Mooreii, Wright 3
Orbignyanum, Cotteau (F.S.)
Parkinsoni, Desor .
pentagonum, McCoy

placenta, Agassiz (F.S.)
planissimum, dgassiz (F.S.)
radiatum, Wright
subangulare, Goldfuss (F.S.)
subcomplanatum, d’Orbigny (F.S.)
superbum, Agassiz (F.8.)
tetragramma, Agassiz

vagans, Phillips

versipora, Phillips .

Nodoti, Cotteau; see Pedina Smithil,

PYGASTER, Agassiz

brevifrons, MeCoy ; see Pygaster semisulcatus.
conoideus, Wright :
dilatatus, Agassiz (F.S.) . :
Edwardseus, Buvignier ; see Pygaster umbrella.
Gresslyi, Desor (F.S.)

laganoides, Agassiz (F.S.)

macrocyphus, Wright (F.S.)

macrostoma, Wright

Morrisii, Wright

patelliformis, Agassiz (¥F.S.)

pileus, Agassiz (F.S.)

semisuleatus, Phillips :
sublevis, McCoy ; see Hyboclypus Meereitarins.
tenuis, Agassiz (F.S.)

umbrella, Agassiz

Pyeurus, d’Orbigny

acutus, Agassiz (F.S.)

Blumenbachii, Koch and Dunker

costatus, Wright c
Davoustianus, Davoust ; see Pygurus Michelini.
depressus, dgassiz (F.S.)

479

PAGE

140
120
121
136
112
127
118
137
456
138
132
110
139
114
115
138
141
131
141
136
137
139
123
124

273

278
288

287
287
290
463
280
288
289
463

290
282
391
409
400
397

409

480 INDEX.

Pyeurus emarginatus, Phillips; see Clypeus subulatus.
‘ giganteus, Wright; see Pygurus Hausmanni.
is Hausmanni, Koch and Dunker
rs Icaunensis, Cotteaw (F.S.) .

» Jdurensis, Marcou (F.S.)

Me Marmonti, Beaudouin (F.S.)
35 Michelini, Cotteau

es orbiculatus, Leske (F.S.)

5 pentagonalis, Phillips

» Phillipsi, Wright

» tenuis, Desor (F.S.)

RaBDOCIDARIS, Desor

a maxima, Goldfuss

ee Moraldina, Cotteau .

35 nobilis, Goldfuss (F.S.)
Orbignyana, Desor (F.S.)

SaLENnraADaz, Wright

Savienya, Desor

SIPUNCULOIDEA, Wright

SpaTanGiDA&, Wright

Spatangites bicordatus, Leske ; see Calrites bicorduet

0 carinatus, Leske ; see Collyrites carinata.
be ovalis, Leske; see Collyrites bicordata.
5 ovalis, Leske; see Collyrites ovalis.
93 capistratus, Goldfuss ; see Collyrites capistrata.
Spatangus depressus, Leske; see Echinobrissus scutatus.
35 ovalis, Leske; see a bicordata.
StomMEcHINUs, Desor

P apertus, Desor (F. 8.)

6 bigranularis, Lamarck

se Caumonti, Desor (F.S.)

M3 excavatus, Goldfuss (F'.S8.)

96 germinans, Phillips

Ks gyratus, Agassiz

BS intermedius, Agassiz .

aS lineatus, Gold/fuss (¥.S.)

D microcyphus, Wright

fr multigranularis, Cotteau (F.S.)

30 nudus, Wright

. perlatus, Desmarest (F.S.)

S Orbignyanus, Cotteau (F.S.)

% polyporus, dgassiz (F.S.)

semiplacenta, Desor
‘s serialis, Agassiz (F.S8.)

55 sub-conoideus, Desor ; see Stomechinus germinans.

PAGE

405, 467
mead

5 Ae
410

392
410

395

403

411

19, 226, 460
108

3

21

INDEX. 481

PAGE
Stomecuinus Robinaldinus, Coffeau (F.S.) . ; A q . ~ oa
os Vacheyi, Cotteau (F.S.) - 5 2 : ; « 220

Tetragramma planissimum, Agassiz (F.S.); see Pseudodiadema planissimum.

FOREIGN SPECIES OF THE FOLLOWING GENERA NEARLY ALLIED TO BRITISH FORMS,
BUT WHICH HAVE NOT YET BEEN FOUND IN THE ENGLISH OOLITES.

Acrosalenia : , : : : : : 253—257
Cidaris : : . - : , ae : 59—64
Clypeus : ; : : ; - . - 386—388
Collyrites ; : : : : : : : 324—328
Diplocidaris : : : 3 ; : : : = RxOs
Disaster : : : ‘ : ‘ : - 323—324
Echinobrissus_. : : ‘ : é : : 356—359
Glypticus : ‘ : : : : “ : = 89
Grasia : : : : : : : : . 329
Hemicidaris : ‘ : Z : : 2 : 102—105
Hemipedina : ; ; 2 : : 5 - 169—170
Holectypus : ; 2 ; : , : : 269—272
Magnotia : , 3 : - 3 : . 194—195
Metaporhinus. ; “ : - : 2 : 328—329
Pedina . ; : ‘ : : : ; : 179—182
Polycyphus , : : : : : : . 201—202
Pseudodiadema . : : : : ¢ : 2 136—142
Pygaster : : 5 , : : ; : 287—290
Pygurus : : 6 : ; é ‘ : 409—412
Rabdocidaris : : 5 : : : : 65—66
Stomechinus : : : : : : 4 - 220—225

64.

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PLATE I.

Cidaris from the Lias.

. Ciparis Hpwarpsi, Wright, p. 26. Natural size, and restored to its globular form.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones; magnified three diameters.

. A view in profile of one of the primary tubercles, magnified three times.
. A secondary spine, from an ambulacral area.

The same, magnified five times.

One of the primary spines, magnified three times.

Lateral view of a jaw and tooth, magnified one and a half times. This specimen
shows a portion of the buccal membrane, with the spines which clothed the same.

Cidaris from the Inferior Oolite.

. Crparis Boucnarnu, Wright, p. 36. Shell natural size, showing the base.
. Ditto, a side view of the same.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified four diameters.

. Ciparis Wricatit, Desor, p. 39. ‘Test the natural size, showing the upper surface.
. Test the natural size, showing a lateral view.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified four times.

d. A primary spine, supposed to belong to C. Wrightit.

S

. Another spine, referred to the same species.

A portion of the same, magnified four diameters.

. Crparis Fowxsri, Wright, p. 32. Natural size, showing the base of the test, with

the jaws in situ.

. Lateral view of the same, showing the projection of the jaws.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified three diameters.

. Portion of a spine attached to the test, this specimen belongs to the Museum of

Geology, Jermyn Street.

. Dirtociparis Wricutu, Desor, p. 58. Fragment of a spine.
. The same, magnified two and a half diameters.
. NOV. Sp.

bh
ND

RR a pee
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LIOR ETOP
= eA cen

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Fig.

. Fragment of a spine attached to the test “a,

PLATE II.

Cidaris from the Coralline Oolite.

. Ciparis Smirnir, Wright, p. 50. Under surface of the test, natural size, showing

the jaws 2 situ.

. Lateral view of another specimen, natural size.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the

poriferous zones, magnified two diameters.

. Inter-ambulacral plate, with its primary tubercle seen im profile, and magnified two

diameters.

3

’ magnified two diameters.

. Ciparrs FLoricemma, Phillips, p. 44. Test with spines attached, on a slab of

Coralline Oolite.

. A large test, natural size, showing the base and mouth opening.
. Lateral view of the same test, natural size.
. Primary spines of Cidaris florigemma, natural size.

Head, neck, and acetabulum of the same, magnified two diameters.

. Small, spatulate, secondary spines, magnified three and a half times.
. One inter-ambulacral plate, and a portion of an ambulacral area with the poriferous

zones; magnified two diameters.

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PLATE III.

Hemicidaris from the Inferor Oolite.

. HmmIcIDARIS PUSTULOSA, Agassiz, p. 73. Upper surface of the test, natural size.
. Lateral view of the same, natural size.

. Two inter-ambulacral plates, and a portion of an ambulacral area, showing the two

upper pairs of semi-tubercles and poriferous zones; magnified three diameters.

. A primary tubercle seen in profile, magnified two diameters.
. Apical disc, magnified two diameters.

. Hemicrparis GranuLosa, Wright, p..71. Upper surface of the test of a small urchin,

natural size.

. Base of a large specimen, showing the mouth opening.
. Lateral view of the same test, both the natural size.

One inter-ambulacral plate, and a portion of an ambulacral area with the poriferous
zones; magnified three diameters.

. Inter-ambulacral plate and tubercle seen in profile, magnified three times.

fTemicidaris from the Stonesfield Slate and Great Oolite.

Hxmiciparis Stokes, Wright, p. 75. Test natural size, imbedded in Stonesfield -
Slate.

. One inter-ambulacral plate, and a portion of an ambulacral area with the poriferous

zones ; magnified three diameters.

. Apical disc, magnified two diameters.

. Hemicrpartis Icaunznsts, Cotteau, p. 90. Lateral view of the test, an interior

mould.

. Upper surface of the same, both the natural size.

. HEMicIDARIs MINOR, Agassiz, p. 80. Test natural size, showing a lateral view.
. Upper surface, magnified two diameters.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones; magnified three diameters.

. Inter-ambulacral plate and tubercle, seen in profile, and magnified three diameters.

. Hemictparis Lucrensts, @’Oréd.,p.78. Test natural size, showing the upper surface.
. Base of the same, showing the mouth opening, both the natural size.

. Lateral view of the same test. .

. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified four diameters.

. Inter-ambulacral plate and tubercle, seen in profile, magnified four times.

Sf

Apical disc, magnified three diameters.

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PLATESV.

Hemicidaris from the Great Oolite.
Fig.
1 a. Hemicrparis Bravenpert, Wright, p. 84. Upper surface of the test, natural size.
6. Lateral view of the same, both the natural size.
c. One inter-ambulacral plate, and a portion of an ambulacral area, magnified three
diameters.
d, An inter-ambulacral plate and tubercle, seen in profile, and magnified three times.
e. Mouth opening and peristome.
J. Apical disc, magnified two diameters.

re)

a. Hemiciparis Wrieuti, Desor, p. 88. Upper surface of the test, natural size.

6. Lateral view of the same, natural size.

c. Apical disc, magnified two diameters.

d. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous
zones ; magnified three times.

e. Base of an ambulacral area, showing the semi-tubercles.

f. An inter-ambulacral plate and tubercle, seen in profile, and magnified twice.

3 a. Hemiciparis Smrrait, Woodward. Under surface, showing the base, natural size.
6. Lateral view of the same, natural size.

Hemicidaris from the Purbeck Beds.

ee

a Hemiciparis Purseckensis, Fordes, p. 98. Lateral view, showing likewise the
upper surface, natural size.

6. Two inter-ambulacral areas, and a portion of an ambulacral area, with the poriferous
zones; magnified three times.

c. Primary spine, natural size, showing the head, ring, and neck, magnified four times.

d. A portion of the stem, with the same, magnified.

5 a. Crparis Smiruit, Wright, p. 50. Primary spine, with the surface of the stem, niag-
nified three times.
6, c. Head, milled ring, and neck of the same, magnified four times.
d. Vhe acetabulum.
e. A transverse section.

6 a. Crparis Inminsterensis, Wright, p. 31. Inter-ambulacral plate, and a portion of an
ambulacral area, natural size.
6. The same, magnified three diameters. ‘The only fragment of the species I know.

7 a. Crparis Braprorpensis, Wright, p. 42. Inter-ambulacral plates, natural size.
6. The same, magnified two and a half diameters.
c. Primary spine, found in the same bed of Bradford Clay.
d. The same, magnified three diameters.

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PLATE] V.*

Hlemicidaris from the Coralline Oohte.

a. HEMICIDARIS INTERMEDIA, Leming, p. 92. Upper surface of the test, natural size.
6. Under surface, showing the mouth opening, with the jaws and teeth in sitw.

ce. Lateral view of the test “a.”

e. Inter-ambulacral plate and tubercle, seen in profile, and magnified three diameters.
d. Two inter-ambulacral plates, and a portion of an ambulacral area, showing the upper

pair of semi-tubercles and poriferous zones; magnified three diameters.

. One of the jaws, magnified two diameters.
. Apical dise magnified two diameters.
. Test with spines attached, imbedded in a slab of Coralline Oolite.

2. Outline of a conical variety of test in my collection.

yj. A small spatulate tertiary spine, natural size.

k. The same, magnified five times.

7. A small secondary spine, natural size.
m

m

0

.aes NY

. The same, magnified five times.
. A primary spine, natural size.
. The same, magnified twice.

Hemicidaris from the Portland Oolite.

2 a. Hemicrparis Davipsoni, Wright, p. 96. Upper surface of the test, natural size.
6. Lateral view of the same, showing the single row of semi-tubercles.
c. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous
zones; magnified three diameters.
d. An inter-ambulacral plate and tubercle seen in profile, and magnified twice.
e. Mouth opening and peristome, natural size.

* In consequence of the artist having by mistake lettered Plate IV Plate V, and Plate V Plate IV, the
reference in the text does not agree with the numbers now unavoidably adopted, as the text and plates were
both printed before the error was discovered. This, however, is the less to be regretted, as any confusion

which might have arisen will now be prevented when the reason for the discrepancy is explained.
T. W.

Hulbnamdel & Walton

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PLATE VI.

Pseudodiademas from the Inas.

1 a. PssupopiapEmA Moors, Wright, p. 110. ‘Test, the natural size.
6. Upper surface of the same, magnified two diameters.
c. Base and mouth opening of the same, magnified two diameters.
d. Two inter-ambulacral plates, and a portion of an ambulacral area, with the pori-
ferous zones; magnified four times.

Pseudodiademas from the Inferior Oolite.

2 a. PSEUDODIADEMA DEPRESSUM, Agassiz, p. 112. Upper surface of the test, natural size.

6. Base and mouth opening of the same, natural size.

c. Lateral view of the same, natural size.

d. Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous
zones; magnified three diameters.

e. Fragment of a spine, magnified four diameters.

J. An entire spine, magnified four diameters.

g. Base of an ambulacral area, showing the tubercles and trigeminal arrangement of
the pores in this region, magnified three times.

h. Inter-ambulacral plate and tubercle, seen in profile, magnified three times.

7. A small specimen with its spines attached, lying on a block of Pea Grit.

Pseudodiademas from the Great Oolite.

3 a. PsEUDODIADEMA PENTAGONUM, J/‘Coy, p. 115. Upper surface of the test, natural size.
6. Lateral view of the same, natural size.
ec. A portion of an ambulacral area, with the poriferous zones, showing the bigeminal
arrangement of the pores, magnified four times.
d. One inter-ambulacral plate, and a portion of an ambulacral area with the poriferous
zones; magnified four times.
4, Psrupop1apEMA Parxinsoni, Desor, p. 114. Test and spines, copied from Parkinson’s
‘Organic Remains.’

Pseudodiademas from the Cornbrash.

5 a. PsEUDODIADEMA HOMOSTIGMA, Agassiz, p. 118. Test, the natural size.
i. Upper surface of the same, magnified two diameters.
c. The base and mouth opening, magnified two diameters.
d. Lateral view of the same, magnified two diameters.
e. T'wo inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous
zones; magnified five times.
f. An inter-ambulacral plate and tubercle, magnified five times.

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C.

3 a.
b.

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d.

é.

PLATE VII.

Pseudodiademas from the Cornbrash.

PsnupoprapmMa Baityt, Wright, p. 120. Upper surface of the test, natural size.

Under surface and mouth opening of the same, natural size.

Lateral view of the same, natural size.

Half of the base, showing the peristome, &c., magnified three diameters.

Half of the upper surface, magnified three diameters.

One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous
zones; magnified six diameters.

A plate and tubercle, seen in profile, magnified six diameters.

Psrvpop1apEMA Baxgria, Woodward, p.121. Upper surface of the test, natural size.
Lateral view of the same, natural size.
One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones; magnified four diameters.

Pseudodiademas from the Coralline Oohte.

PsEUDODIADEMA RADIATA, Wright, p.131. Upper surface of the test, natural size.
Under surface of the test, natural size.

Lateral view of the test, natural size.

The half of the upper surface, magnified three diameters.

The half of the under surface, magnified three diameters.

J. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified six diameters.

. An inter-ambulacral plate and tubercle, seen in profile, magnified six times.

PsEUDODIADEMA VERSIPORA, Phillips, p. 124. Upper surface of the test, natural size.

. Base and mouth opening of the same, natural size.
. Lateral view of the same, natural size.

. Half of the upper surface, magnified two diameters.
. Half of the under surface, magnified two diameters.

One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous
zones ; magnified four diameters.

. An inter-ambulacral plate and tubercle, seen in profile, and magnified four times.

W. i Baily, delet ith,

rinted. by Hullmandd & Walton .

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PLATE VIII.

Pseudodiademas from the Coralline Oolite.

. PskUDODIADEMA HEMISPHHRICUM, Agassiz, p. 127. Upper surface of the test, natu-

ral size.

. The half of the under surface of the same, natural size.
. A lateral view of the same, the natural size.
. The half of a portion of an inter-ambulacral area, and a portion of an ambulacral

area, with the poriferous zones; magnified twice.
Apical disc, magnified two diameters.
Base of an ambulacral area, showing the trigeminal pores in this region.

. PsEUDODIADEMA MAMILLANUM, Roemer, p. 1382. Upper surface of the test, natural

SIZe.

. Under surface of the test, natural size.
. Lateral view of the test, natural size.
. ‘The half of a portion of an inter-ambulacral area, and a portion of the ambulacral area,

with the poriferous zones ; magnified three diameters.

. Ciparis Bovcuaroi, Wright, p. 36. Lateral view of a very fine test of this species,

from the Inferior Oolite.

. One inter-ambulacral plate, and a portion of an ambulacral area of Crdaris Bouchardii,

with a small secondary spine found on the test, magnified four times.

Ciparis FLoRIGEMMA, Phillips, p. 44. Under surface of a young test, natural size.

Upper surface of the same, natural size.

Lateral view of the same, natural size.

One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous
zones, magnified three diameters.

Inter-ambulacral plate and tubercle, seen im profile, and magnified three times.

5. Diptociparis Dusori, Wright, p. 56. Inter-ambulacral plate, ambulacral area, and

Qa Ve

poriferous zones; natural size; the only fragment I know.

. Hemrcrparis Ramsayu, Wright, p.83. Lateral view of the test, natural size.

. Upper surface, magnified three diameters.

. Under surface, magnified three diameters.

. ‘Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

zones ; maguified five times.

. The apical disc, magnified once and a half.

3

>

Printed by Hullmandel & Walton -

R. Bone, del. et lith

Fig.

3 a.

PLATE IX.

Femipedinas from the Inas.

. Hemrprpina Broust, Brodrip, p.144. Test with spines zz si¢u, natural size.
. A primary spine, magnified three times.

. Hemrpepina Bowrrzanxit, Wright, p.145. Test with spines, natural size.
. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones ; magnified five diameters.

. A primary spine, magnified three times.

Hemrpepina (DiapEma) Suriaun, Leymerie, p. 146. From the Lias of France
copied from the ‘Mem. de la Société Geéologique de France,’ t. ui, pl. 24, fig. 1.
To show the form and structure of the test of a very rare allied species.

. One of the inter-ambulacral plates and poriferous zones, magnified.

. Hemiprpina Jarvinu, Wright, p.146. Upper surface of the test, natural size.

. Under surface of the test, natural size.

. Lateral view of the test, natural size.

. Upper surface of the test, magnified three diameters.

. Under surface of the test, magnified three diameters.

. Lateral view of the test, magnified three diameters.

. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones, magnified nine times.

Hemiprpina Erunripen, Wright, p. 148. Upper surface of the test, natural size.

. Under surface of the test, natural size.

. Lateral view of the test, natural size.

. Upper surface of the test, magnified three diameters.

. Under surface of the test, magnified three diameters.

. Lateral view of the test, magnified three diameters.

. One inter-ambulacral plate, and a portion of an ambulacral area, with the poriferous

zones, magnified nine times.

rinted by Hullmen

i

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PLATE X.

Hemipedinas from the Inferior Oolite.

. Hemrpepina Baxsrt, Wright, p. 149. Under surface of the test, natural size.

. Upper surface of the test, magnified two diameters.

. Lateral view of the test, magnified two diameters.

. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

rows ; magnified two diameters.
Inter-ambulacral plate and tubercle, seen in profile, and magnified three times.
The apical disc, magnified three diameters.

. HEemIpepiIna PERFORATA, Wright, p. 151. Lateral view of a test, natural size.

. Upper surface, magnified two diameters.

. Under surface, magnified two diameters.

. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

rows; magnified six times.

. Apical disc, magnified two diameters.
. Base of an ambulacral area, showing the trigeminal arrangement of the poriferous

zones in this region.

. HEMIPEDINA TETRAGRAMMA, Wright, p. 152. Lateral view of the test, natural size.
. The upper surface, magnified two diameters.
. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

zones ; magnified five diameters.

. Hemrpepina Waternouset, Wright, p. 154. Lateral view of the test, natural size.

. Upper surface, magnified two diameters.

. Lateral view, magnified two diameters.

. Apical disc, magnified four diameters.

. Two inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

zones ; magnified three diameters.

. Hemipepina Bonu, Wright, p. 156. Lateral view of the test, natural size.

. Upper surface of the test, magnified two diameters.

. Under surface of the test, magnified two diameters.

. Tbree inter-ambulacral plates, and a portion of an ambulacral area, with the poriferous

zones ; magnified six diameters.

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PLATE XI.

Hemipedinas from the Coral Rag.

. Hemrpepina Marcnamensis, Wright, p. 161. Base of the test, natural size.
. One inter-ambulacral plate, a portion of the ambulacral area, and poriferous zones,

magnified twice.
Lateral view of a primary tubercle, showing its prominent boss, with smooth summit.

. Hemrpepina tusercutosa, Wright, p. 164. Upper surface of the test, natural

size.

. Base of the test, natural size.
. Lateral view of the test, natural size.
. Two inter-ambulacral plates, a portion of the ambulacral area, and poriferous zones,

magnified three times.

. Lateral view of a primary tubercle, showing the prominent boss, with its smooth

summit, and the scrobicular granules encircling the areola.
A primary spine, magnified three times.

Hemicidaris from the Great Oolite.

Hemiciparis BravenpDER1, Wright, p. 84. ‘Test and spines in stu, onaslab of Great
Oolite from Stratton, near Cirencester.
A primary spine, magnified three times.

Bone, del et lith

Prmted by Hullhnandel & Walton:

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10.

PLATE XII.

Henipedinas from the Great Oolite, Coral Rag, and Kimmeridge Clay.

. Hemrpepina Coraiina, Wright, p. 163. Portion of the base and jaws iz situ.
. Fragment, with plates and spines, from the Coral Rag, Wilts.

. One inter-ambulacral plate, magnified three times.

. A primary spine, from fragment 4, magnified three times.

. Hemipepina Morris, Wright, p. 166. A fragment of the test, natural size.
. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified four

times.

. A primary spine, magnified four times.

. Hemipepina Cunninetoni, Wright, p. 167. A fragment of the test, natural size.
. The same, magnified four times.

. Hnmipepina mMicroeramMA, Wright, p. 159. Upper surface of the test, natural size.
. A lateral view of the test, natural size.
. One inter-ambulacral plate, a portion of the ambulacra, and poriferous zones, magnified

four diameters.
CIDARIS SPINOSA, Agassiz, p. 53. Spine, natural size.

. Crparis Botoniansis, Wright, p. 53. A flattened spine with prickly ridges.
. Aspine with thorny prickles, resembling C. spinosa.

_ Hemirepina Davipsont, Wright, p. 156. A lateral view of the test, natural size.

. ‘The upper surface of the test, natural size.

_ The under surface of the test, natural size.

- One inter-ambulacral plate, a portion of the ambulacra, and poriferous zones;

magnified six diameters.

_ Hemreepina Woopwarnt, Wright, p. 158. A lateral view of the test, magnified

twice.

. Upper surface of the test, magnified twice.
_ Under surface of the test, magnified twice.

One inter-ambulacral plate, ambulacra, and poriferous zones, magnified six times.

PsEUDODIADEMA MAMMILLANUM, Roemer, p. 132. Primary spe, magnified three

times.

PsrvpopiapEMA vERsIPORA, P/illips, p. 124. Primary spine, magnified three times.

Rappociparis maxima, Minster, p. 65. Primary spine, natural size.

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PLATE XIII.

Pedinas from the Inferior Oolite.

. Pepina rotara, Wright, p. 173. Base of the test, natural size.

. Upper surface of the test, showing the apical disc, natural size.

. Lateral view of the test, natural size.

. Apical disc, magnified two and a half diameters,

. Inter-ambulacral plate, ambulacral area, and poriferous zones, magnified four times.

. Pepina Smirait, Forbes, p. 176. Fragment of the test, natural size.
. Inter-ambulacral plate, ambulacral area, and poriferous zones, magnified three times.

Lateral view of another specimen, showing the ambulacral and inter-ambulacral
areas. ;

Glypticus from the Coral Rag.

. GLYPTICUS HIEROGLYPUICUS, Goldfuss, p. 186. Under surface of the test, natural

size.

. Upper surface, natural size.
. Lateral view, natural size.
. Apical disc, magnified two and a half times.

One of the large primary tubercles, magnified two and a half times.
Two inter-ambulacral plates, showing the sculpture, ambulacra, and zones, magnified
four times.

— Polycyphus from the Inferior Oolite.

. Porycypnus Normannus, Desor, p. 196. Test, upper surface, natural size.
. Upper surface, magnified once and a half.
. Under surface, showing the mouth opening and peristome, magnified once and a

half.

. Apical disc, magnified four times.

Lateral view of the test, magnified once and a half.
Inter-ambulacral and ambulacral areas, showing the arrangement of the tubercles,

magnified six times.

Porycypuus Dustonecuampsu, Wright, p. 199. Test, upper surface, natural size.
Upper surface, with the apical disc, magnified twice.

Under surface, with the mouth and peristome, magnified twice.

Lateral view, magnified twice.

Apical disc, magnified twice.

Inter-ambulacral and ambulacral areas, showing the arrangement of the tubercles,

magnified six times.

PLATE XIII (continued).

Magnotia from the Inferior Oolite.
Fig.
6 a. Macnorra ForBust, Wright, p. 191. U pper surface of the test, natural size.
6. Upper surface of the test, magnified once and a half.
ce. Under surface of the test, magnified once and a half.
d. Lateral view of the same, magnified once and a half.
e. Apical disc, magnified four times.
J. Inter-ambulacral and ambulacral plates, with the poriferous zones, showing the
arrangement of the tubercles and the unigeminal disposition of the pores.

Printed. by Hullmande=! & Walton

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PLATE XIV.

Stomechini from the Inferior Oolite.

. STOMECHINUS GERMINANS, PAillips, p. 204. Lateral view of the test, natural size.
. Base of the test, showing the wide mouth opening and deeply notched peristome.
. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified three

times,
Base of an inter-ambulacral area, showing the arrangement of the ranks of pores,
magnified three times.

STOMECHINUS INTERMEDIUS, Agassiz, p. 208. Upper surface of the test, natural size.

. Base of the test, showing the mouth opening and peristome, natural size.
. Lateral view of the same, natural size.
. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified three

~ times.

. Apical disc, magnified two diameters.

. STOMECHINUS BIGRANULARIS, Lamarck, p. 210. Upper surface of the test, natural

size.
Base of the test of a larger specimen, showing the small mouth opening, natural size.

. Lateral view of a, showing the excentral apical disc.
. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified three

times.

. Apical disc, magnified two diameters.

Stomechinus from the Coral Rag.

. STOMECHINUS GYRATUS, Agassiz, p. 215. Upper surface of the test, natural size.
. Base of the test, showing the mouth opening and peristome, natural size.

Lateral view of the same, showing the tubercular inter-ambulacra, natural size.
Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified three times.
Apical disc, magnified two diameters.

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PLATE XV.

Stomechini from the Great Oolite and Coral Rag.

. STOMECHINUS MicrocyPuus, Wright, p. 213. Lateral view of the test, natural size.
. Two inter-ambulacral plates, a portion of an ambulacral area, and poriferous zones,

magnified four times.

. STOMECHINUS NuDUS, Wright, p. 217. Upper surface of the test, natural size.

. Base of the test, natural size.

. Lateral view of the test, natural size.

. T'wo inter-ambulacral plates, a portion of an ambulacral area, with the poriferous

zones, magnified four times.

. Apical disc, magnified three diameters.

Acrosalenias from the Inas and Cornbrash.

. ACROSALENIA MINUTA, Buckman, p. 230. Test, the natural size. Lower Lias.
. The upper surface of the same test, magnified four times.
. Base of another specimen, natural size.

. ACROSALENIA HEMICIDAROIDES, Wright, p. 234. Upper surface of the test, natural

SIZe.

. Base of the same test, natural size.
. Lateral view of the same, natural size.

d. Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous

mM.

zones, magnified three times.

. Base of the ambulacral and inter-ambulacral areas, showing the trigeminal pores near

the peristome, magnified three times.

. Lateral view of a primary tubercle and its prominent boss, magnified three times.

. Base of a small specimen, showing the mouth opening and jaws zz s¢tw.

. One of the jaws of another specimen, magnified.

. Apical disc complete, showing the compound sur-anal plate, magnified two diameters.
. Test with spines zz situ, on a slab of Forest Marble.

. Three primary spines, showing their simple and trifid termination, natural size.

Base of a primary spine, showing the milled ring and head, magnified three times.

m. A secondary spine, natural size and highly magnified.

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PLATE XVI.

Acrosalenias from the Inferior and Great Oolite.

. Acrosatenta Lycerin, Wright, p. 232. Upper surface of the test, natural size.

6. Under surface of the same, showing the wide decagonal peristome, natural size.

. Lateral view of the same, showing both areas.

d. Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous

zones, magnified three times.

e. Base of an ambulacral area, showing the trigeminal ranks of pores in this region,

magnified three times.

j. A primary tubercle, with its prominent conical boss, highly magnified.

2 a. AcrosaLenia pustuLara, Forbes, p. 242. Upper surface of the test, natural SIZe.

b

C.

d.

G

. Under surface of the same, showing the wide decagonal peristome, natural size.

Lateral view of the same, showing the small ambulacral tubercles, natural size.

‘Two inter-ambulacral plates, a portion of an ambulacral area, with the poriferous
zones, magnified three times.

. A primary spine, natural size, and the base of the same, magnified three diameters.

jf. The body and spines 2m sztw, on a slab of Great Oolite, natural size.

3 a. AcrosaLENIA Wixronit, Wright, p. 246. Upper surface of the test, natural size.

b

C.

. Under surface of the same, natural size, showing the narrow mouth opening.
Lateral view of the same, natural size, showing the wide miliary zone.

d. Two inter-ambulacral plates, a portion of an ambulacral area, and the poriferous

iss}

4a

b

6.

zones, magnified three times.

. A primary tubercle on its large prominent boss, magnified three times.

. Acrosatenta Lowxzana, Wright, p. 240. ‘Vest and spines zz situ, natural size, on a
slab of Forest Marble.
. One of the primary spines, magnified five times, with transverse section of the same.

Spine of Crparis Yuoviuensis, Vraght. ‘These new species will be described in
Ciparis Moorxi, Wright. J the Appendix.

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PLATE XVII.

Acrosalenias from the Lias, Cornbrash, and Coral Rag.

- ACROSALENIA DucorAvA, Haime, p. 247. Upper surface of the test, natural size.
. Under surface of the test, natural size, showing the concave base and equal-lobed

peristome.
Lateral view of the same, natural size, showing the magnitude of the equatorial
tubercles. ;

. Upper surface of the inter-ambulacral and ambulacral areas, magnified four times.
ah = 5 2 é
. ‘Two equatorial inter-ambulacral plates and a portion of the ambulacral area, magni-

fied four diameters.

The apical disc, with all the elements of the sur-anal plate iw situ, magnified three
times.

The apical disc of another specimen, showing the single crescentic genital plate,
magnified four times.

Base of the ambulacral and inter-ambulacral areas, with two lobes of the peristome.
magnified four times.

. Lateral view of an equatorial primary tubercle, with its highly crenulated boss.

. Slab from the Coralline Oolite of Malton, with tests and spines zx sé¢u, natural size.
. Primary spine, natural size, with base and transverse section, magnified four times.
. Secondary spine, magnified, showing the longitudinal lines on its surface.

. ACROSALENIA MINUTA, Buckman, p. 230. ‘Test, the natural size.
. Base of the same, magnified three diameters.

Upper surface of the same, magnified three diameters.

. Lateral view of the same, magnified three diameters.
. Two inter-ambulacral plates, a portion of an ambulacral area, and poriferous zones,

magnified ten times.

. ACROSALENIA SPINOSA, Agassiz, p. 238. Upper surface of the test, natural size.

. Base of the same, natural size.

. Lateral view of the same, natural size.

. Two inter-ambulacral plates, a portion of the ambulacral area, and poriferous zones,

magnified four times.
The conical boss, with its crenulated summit, and perforated tubercle, magnified.

f. The apical disc, with its single sur-anal plate, magnified four diameters.

Vig.
A a.
bh.
C.

13.

15.

PLATE XVII (continued).

AcrosaLEenta Lowzana, Wright, p. 240. Upper surface of the test, natural size.

Lateral view of the test, natural size.

‘Two inter-ambulacral plates, a portion of the ambulacral area, and poriferous zones,
magnified three diameters.

Acrosatunta Winronu, Wright, p. 246. The apical disc, magnified three times.

Spines of unknown Species.

Globular spine from the Great Oolite near Bath, magnified three times.

Spine from the Forest Marble of Upper Cubberly, near Cheltenham, natural size,
and magnified three times.

Spine from the Great Oolite of Bath.

. Spine ditto ditto.

Spine from the Stonesfield slate of Eyeford, Gloucestershire, and surface magnified
five times.

Spine from the Stonesfield slate of Eyeford, Gloucestershire, and surface magnified
four times.

Spine from the Great Oolite of Minchinhampton, natural size.

Spine from the Pea-grit, near Cheltenham, fragment natural size.

Spine from the Lower Lias of Bushley, near Tewkesbury, and a portion magnified
five times.

Spine from the Lower Lias of Lyme Regis, and portion magnified four times.

Spine ditto ditto, and portion magnified five times.

Spine ditto ditto, and portion magnified three times.

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PLATE XVIII.

Holectyp: from the Inferior Oolite and Cornbrash.
Fig.
1 a. Houecrypus prpressus, Leske, p. 260. Upper surface, natural size.
6. The base, showing the mouth and anal openings, natural size.
c. A side view of the same test, natural size.
d. Ambulacral areas, poriferous zones, and inter-ambulacral plates, magnified three
diameters.
e. Primary tubercle from the upper surface, with its circle of areolar granules, magnified
seven times.
J. Primary tubercle from the base, magnified seven times.
g. Under surface of another specimen, showing the jaws iz stu, natural size.
A. Portion of a primary spine, magnified eight times.
?. The apical disc, magnified three and a half times.

2 a. HOLECTYPUS HEMISPHARICUS, Agassiz, p. 264. Upper surface, natural size.
6. Under surface, natural size.
c. Posterior view, showing the marginal anal opening.
d. Ambulacral area, poriferous zones, and three inter-ambulacral plates, magnified three
diameters. 7
e. The apical disc, magnified three times.
/. Lateral view, showing the greater length of the posterior half.
g. A conical variety, showing the height of the pyriform marginal anal opening.
h. The base of a large specimen.

Holectypus from the Coral Rag.

3 a. Horzctrypus ostoneus, Wright, p. 267. Upper surface, natural size.
6. Base of a small specimen, natural size.

c. Lateral view of a, natural size.
d. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified four

diameters.

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PLATE XIX.

Pygasters from the Inferior Oolite.
Fig. :
1 a. Pyeastur sEmisuLcatus, Phillips, p. 275.
6. Under surface, natural size.
c. Lateral view of the same test.

Upper surface, natural size.

d. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified three
diameters.

e. Primary tubercle, with the areolar circle of granules, magnified eight times.

j. Primary tubercle of the ambulacral area, magnified eight times.

g. Primary tubercle from the base, magnified eight times.

h. Primary tubercle from the ambulacral area, magnified eight times.

2 a. Pyeaster conoiDEus, Wright, p. 278. Upper surface, natural size.
6. Under surface, natural size.
c. Lateral view, natural size.
d. Ambulacral area, poriferous zones, and two inter-ambulacral plates, maghited two
diameters.
e. Primary tubercles from the upper surface, magnified eight times.
f. Primary tubercles from the base, magnified eight times.

R. Bone, del. eb Tith Hull 1 & Wal
Bone, del E ith Printed by Hullmandel & Walton

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PLATE XX.

Pygaster from the Cornbrash.
Fig.
1 a. Pyeaster Morrisi1, Wright, p. 280. Upper surface, natural size.
6. Under surface, natural size.
c. Lateral view, natural size.
d. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified four
diameters.
e. Primary tubercle from the upper surface, with areolar circle of granules, magnified
eight times.
J. Primary tubercle from the base, magnified eight times.

Pygaster from the Coral Rag.

2 a. PYGASTER UMBRELLA, Agassiz, p. 282. Upper surface, natural size.

6. Under surface of another specimen, natural size.

c. Lateral view of a.

d. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified three

diameters.

e. A portion of the apical disc, showing the four perforated ovarial plates and madrepori-
form body, magnified two and a half times.
| j. A primary tubercle, with its areolar circle of granules, magnified eight times.

g. A primary tubercle from the base, magnified eight times.

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PLATE XXII.

Hyboclypi from the Inferior Oolite.

Fig.
1 a. HyBochypus acaricirormis, Forbes, p. 292. Upper surface, natural size.
6. Under surface of the same test. .
c. Lateral view of the same.
d. Ambulacral area,.poriferous zones, and two inter-ambulacral plates, magnified two
and a half times.
e. Basal portion of an ambulacral area, showing the trigeminal pores near the peristome.
fj. Primary tubercle from the upper surface.
g. Primary tubercle from the base, both highly magnified.

2 a. HYBOCLYPUS GIBBERULUS, Agassiz, p. 298. Upper surface, natural size.

6. Under surface of the same test.

c. Lateral view of the same.

d. Front view, showing the elevation of the gibbous crest, and the depression of the
single inter-ambulacrum.

e. The apical disc, magnified two and a half times.

f. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified two
and a half times.

g. Primary tubercle from the upper surface, surrounded by miliary granules, highly
magnified.

Printed by Hudlmandel & Walton

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PLATE XXII.

Hyboclypi from the Inferior Oolite.

Fig.
1 a. Hysociypus ovauis, Wright, p. 301. Upper surface, natural size.
6. Under surface of the same test.
c. Lateral view of the same.
d. Ambulacral area, poriferous zones, and two inter-ambulacral plates, magnified three
diameters.
e. The apical disc, magnified three diameters.
/. Basal portion of an ambulacral area, showing the distance of the pores apart, in this
region, from the size of the plates, magnified three times.

2 a. Hypocnyeus caupatus, Wright, p. 296. Upper surface, natural size.
6. Under surface, natural size.
c. Lateral outline of the same.
d. Upper surface of the common form of this urchin, with the disc.
e. Base of the same test.
j. Laterai view of a broad variety.
2. Upper surface of the same test.
&. Outline of a conical variety.
gy. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified three times.
h. The apical disc of d, magnified four diameters.

Collyrites from the Inferior Oolte.

3 a. COLLYRITES RINGENS, Agassiz, p. 306. Upper surface, natural SIZe.

6. Under surface of the same test.

ce. Lateral view of the same.

d. Posterior view, showing the position of the vent, and the arch formed by the posterior
pair of ambulacra.

e. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified three times.

J. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified three times.

g. Primary tubercles, and miliary granules, highly magnified.

h. Oviductal holes, madreporiform body, and terminations of the three anterior
ambulacra.

i. Diagram of the structure of the test ; the plates of the disc, and those above the vent

not made out.

C.R Bane, del. et ith. Printed by Hulbnandel & Walt

ya!

PLATE XXIII.

CoLLYRITES FROM THE INFERIOR OoxniTE anp Corat Rac.

Inferior Oolite Species.

1 a. Contyrires ovauis, Leske, p. 314. Upper surface, natural size.
4. Under surface of the same test.
c. Lateral view of ditto.
d. Posterior view of ditto.
e. Ambulacral areas, poriferous zones, and inter-ambulacral plates, magnified thrice.
J. Primary tubercles and miliary granules, highly magnified.
g. Anterior view of a smaller test.

Coral Rag Species.

2 a. CottyrirEes BicorData, Leske, p. 319. Upper surface, natural size.
6. Under surface of the same test.
c. Lateral view of ditto.
d. Posterior view of the same, showing the anal opening.
e. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified thrice.
f. Anterior pair of ovarial plates, and madreporiform body, with the single, and
anterior pair of ocular plates, magnified four times.
g. Primary tubercles, and miliary granules, of the dorsal plates, highly magnified.
4. Primary tubercle, and hexagonal areolas from the base ; ditto.

Pi. Sony

Printed by Hulimandel & Walton

© R.Bone, del. et ith.

PLATE XXIV.
EcHINOBRISSI FROM THE INFERIOR OoLite, Great OoLirz, AND CoRNBRASH.

Inferior Oolite and Cornbrash Species.

. HcHINOBRISSUS CLUNICULARIS, Lihwyd, p. 332. Upper surface, natural size.

. Under surface of the same test, natural size.

. Lateral view of ditto ditto.

. Posterior view, showing the anal valley, and inter-ambulacrum.

. Ambulacral area, poriferous zones, and inter-ambulacral plates ; magnified thrice.

Ambulacral area, and petaloid portion of the poriferous zones; highly magnified.
Apical disc, and madreporiform body; magnified four times.

. Primary tubercles, and miliary granules, highly magnified.

Diagram of the upper surface, showing the relative anatomy of the shell.

. The largest test of this species yet found; from the Rev. A. W. Griesbach’s cabmet :

natural size.

Great Oolite Species.

. Ecutvosrrssus Woopwarpl, Wright, p. 337. Upper surface, natural size.

Under surface of the same test, natural size.

. Lateral view of ditto, showing its tumid sides ; natural size.
. Ambulacral area, poriferous zones, and inter-ambulacral plates ; magnified four times.

Upper surface of a large test.

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Printed byHullmamndel & Walton

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PLATE XXV.

EcCHINOBRISSI FROM THE GREAT OoLITE, AND CoRNBRASH.

Great Oolite Species.

. Ecuinosrissus Grisssacui, Wright, p. 340. Upper surface, natural size.

Upper surface of the same, magnified twice.
Under surface, natural size.

. Ditto, magnified twice.
. Lateral view of the test, natural size.

Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified four times.

Cornbrash Species.

. EcHINOBRISSUS ORBICULARIS, Phillips, p. 341. Upper surface, natural size.

Under surface of the same test, natural size.
Lateral view of ditto, showing the poriferous zones.

. Apical disc, with its internal complementary plates, magnified five times.

Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified thrice.

Lateral view of a conoidal variety of this species, from Northamptonshire.

Upper surface of another specimen, showing a greater eccentricity of the apical disc,
a wider anal valley, and a larger vent.

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Printed byHudlmandel & Walton

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PLATE XXVI.
ECHINOBRISSI FROM THE CORNBRASH, AND Coral Rag.
Cornbrash Species.

. Ecuinoprissus quapratus, Wright, p. 344. Upper surface, natural size.
. Under surface of the same test, natural size.
Lateral view of the same, showing the long dorsal slope of the posterior half.

No os

. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified four times.

Coral Rag Species.

a. Ecuinoprissus scuratus, Lamarck, p. 346. Upper surface, natural size.
6. Under surface of the same test, natural size.

c. Lateral view of the same test, showing the tumidity of its sides.

d. Posterior view, showing the anal valley, and large vent.

e. Apical disc, magnified more than four times.

J. Ambulacral area, zones, and inter-ambulacral plates, magnified four times.

a. ECHINOBRIssUS DIMIDIATUS, Phillips, p. 350. Upper surface, natural size.
6. Under surface of the same test, natural size.

c. Lateral view of ditto, showing the great tumidity of its sides.

d. Ambulacral area, zones, and inter-ambulacral plates, magnified four times.

4 a. Hournogsrissus scuratus, Lamk. A small round variety.
6. Lateral view of this test.
c. Ambulacral area, zones, and inter-ambulacral plates, magnified four times.

Portland Oolite Species.

Ecuinoprissus Broprut, Wright, p. 353. See Pl. XXXV, fig. 1, a, 6,6, d e.

Valton

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PLATE XXVII.

CLYPEIT FROM THE INFERIOR OOoLITE.

. CLYPEUS ALTUS, M Coy, p. 366. Upper surface, natural size.
. Under surface of the same test, natural size.

. Lateral view of ditto, showing the convexity of the dorsal surface, and the deep

undulations of the border.

. Posterior view, showing the structure of the mter-ambulacrum; the length, and

narrowness of the anal valley, and the shape of the vent.

. Ambulacral area, zones, and inter-ambulacral plates, magnified four times.

Apical disc, with the large madreporiform body, small ocular plates, and posterior

complementary plates, magnified five times.

. Cryprus Micuenini, Wright, p. 369. Upper surface, natural size.

6. Lateral view of the same test, natural size.

. Ambulacral area, zones, and inter-ambulacral plates, magnified five times.

This is a rare urchin, on a slab of Inferior Oolite limestone, from Whitwell, Yorkshire,

where it was found associated with Stomechinus germinans, Phillips.

52

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PLATE XXVIII.

Curyreus Priori, Klean.

From the Inferior Oolite.

1 a. Cuyprus Puoru, Klein, p. 360. Upper surface, natural size.

6. Under surface of the same test, natural size.

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PLATE XXIX.

Criyerus Piori, Kleim.
From the Inferior Oolite.

1 a. Cryeeus Prorn, Keim, p. 360. Posterior view, showing the anal valley, oblong
vent, and postero-lateral ambulacra.
6. Lateral view of the same test.
> Ambulacral area, zones, and inter-ambulacral plates, magnified two-and-a-half times.
d. Apical disc, magnified two-and-a-half times.

e. Primary tubercles, and miliary granules, from the upper surface, highly magnified.

f. Ditto, from the base, ditto ditto.

g. Ambulacral area, and poriferous zones, at the base; magnified four times.

h. Mouth-opening, peristome, and oral lobes ; magnified two-and-a-half times.

PL. XX1X

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PLATE XXX.

CLYPrI FROM THE INFERIOR OOLITE.

Ciyprvs Huei. Agassiz, p. 375, upper surface, natural size.

Under surface of the same test, natural size.

Lateral view of the same test, ditto.

Posterior view of the same, showing the shortness of the anal valley, and the size of
the vent.

Ambulacral area, zones, and inter-ambulacral plates, magnified thrice.

Apical disc, madreporiform body, and summits of the ambulacra, magnified.

Cryrrus Micne ini, Wroght, p. 369. Upper surface, natural size.
Under surface of another test, natural size.
Lateral view of a, showing the obliquity of the posterior half of the dorsal surface.

Ambulacral area, zones, and inter-ambulacral plates, magnified thrice.

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PLATE XXXI.

Cuiypeus Acassizi1, Wright.
From the Inferior Oolte.

1 a. Curvrzus Acassizi, Wright, p. 378. Upper surface, natural size.

6. Under surface of the same test, natural size.

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PLATE XXXII.

Ciypegus Acassizi1, Wraght.
From the Inferior Oolite.

la. Cuyexus Acassiait, Wright, p. 378. Lateral view, natural size.

4. Posterior view, showing the shallow anal valley, and superficial oblong veut.

c. Ambulacral area, poriferous zones, and inter-ambulacral plates, inagnified twice and a
half times.

d. Portion of the basal ambulacral area near the mouth, showing the arrangement of
the pores in triple oblique ranks, magnified four times.

e. Tubercles from the base, with miliary granules around them, magnified.

Ff. Tubercles from the upper surface, showing the regular disposition of the granules

. around the areolas, and on the intermediate surface.

C.R.Bone, del. et Hth.

Printed by Hidimandel

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PLATE XXXIII.

Crypxus Miuueri, Wright.
From the Great Oolite.

Cryprus Mirer1, Wright, p. 371. Upper surface of a large specimen lying on a
slab of forest marble, natural size. From Mr. Frederick Bravender’s
Collection. '

. Upper surface of a medium sized specimen from the Great Oolite, natural size.
. Under surface of the same test, showing the central mouth-opening, natural size.
. Lateral view of the same test, showing the shelving character of the posterior half of

the upper surface.

. Common variety of the species, having the apical disc very ex-central posteriorly,

natural size.

. Under surface of the same test, showing the mouth-opening and peristome, ditto.

Apical disc, showing the two pairs of large, triangular genital plates, the small
oculars, the large madreporiform body, and single imperforate genital
plate, magnified about four times.

Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified four times.

Portion of a poriferous zone, showing the inner round holes, the external slit-like
apertures, and the tubercles on the septa, highly magnified.

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PLATE XXXIV.

CiyPEus suBuLAtTus, Young and Bird.
From the Coralline Oolite.

. Cyprus suBuLATUS, Young and Bird, p. 382. Upper surface, natural size.

a
6. Under surface of the test c, slightly enlarged.

S

Lateral view of another test, showing the border, natural size.
d. Posterior view of the same test, showing the short anal valley and vent.
e. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified thrice.
ff. Tubercles and miliary granules from the upper surface, magnified.
g. Apical disc, showing the madreporiform tubercle covering the other elements of the

disc.

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PLATE XXXV.

Ecuinosrissus Bropirtr, Wright.

From the Portland Oolite.

. Ecuinoprissus Bropiui, Wright, p. 353. Upper surface, natural size.

Under surface of the same test, natural size.
Lateral view of the same test, ditto.

. Posterior view of the same, showing the short anal valley, and large vent.

Basal tubercles, with hexagonal areolas, highly magnified.

Pycurus Micueini, Cotteau.

From the Cornbrash.

. Pyeurus Micuenint, Cotteau, p. 392. Upper surface, natural size.

Under surface of the same test, showing the vent and its areola, natural size.
Posterior view of the same, showing the relative position of the vent, and border.

. Lateral view of the same, showing the excentral position of the apical disc, and the

shelving character of the posterior half of the upper surface.

. Ambulacral area, poriferous zones, and ambulacral plates, magnified twice and a

half times.

jf. Apical disc, magnified four times.

3. Apical disc of the same species, copied from M. Cotteau’s work.
the relative anatomy of the discal elements better than in our best
specimen, and exhibits the magnitude of the large madreporiform body,

which covers nearly all the other plates.

This figure shows

XV

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Primed by Hulhnandel & Walton.

R Bone, del. et lath

PLATE XXXVI.

PyGuRus PENTAGONALIS, Phillips.
From the Coralline Oolite.

1 a. Prevrus PENTAGONALIS, Phillips, p. 394. Upper surface, natural size.
6. Under surface of the same test, natural size.
c. Lateral view of the same test, ditto.

d. Apical disc with madreporiform tubercle, magnified.

2a. Pyeurvs punraconaLis, Phillips. A large specimen from the Coralline Qolite of
Malton imbedded in a fragment of that rock. This beautiful fossil

belongs to the Scarborough Museum.
6. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified twice and

a half times.

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Printed by Hulbnandel & Waltan

C.R-Bone del. et lith

PLATE XXXVI.

Pye@uRus PENTAGONALIS, Phillips.
From the Coralline Oolite.

1 a. PyGuRus PENTAGONALIS, Phillips, p. 394. Upper surface, natural size.
6. Under surface of the same test, natural size.
c. Lateral view of the same test, ditto.

d. Apical disc with madreporiform tubercle, magnified.

2a. Pycurus penraconais, Piillips. A large specimen from the Coralline QOolite of
Malton imbedded in a fragment of that rock. This beautiful fossil

belongs to the Scarborough Museum.
6. Ambulacral area, poriferous zones, and inter-ambulacral plates, magnified twice and

a half times.

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PLATE XXXVII.

Pyeurus Costatus, Wright.

From the Coralline Oolite.

1 a. Pyeurus Costatus, Wright, p. 397. Upper surface, natural size.

6. Under surface of the same test, natural size.

c. Posterior view, showing the flatness of the base and the extreme depression of the
upper surface.

d. wo inter-ambulacral plates, poriferous zones, and ambulacral area, magnified three
times.

e. Phylloidal expansion of the ambulacral area near the mouth-opening, showing the
crowding together of the pores in this region, magnified three times.

f. One of the lip-like processes of the mammillated, oval lobes which project over the

border of the peristome, magnified twice.

XXXVI

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PLATE XXXVIIL.

Pyeurus BLuumensacutt, Koch and Dunker.

From the Coralline Oolite.

. Pyeurus Biumenpacnir, Koch and Dunker, p. 400. Upper surface, natural

sIZze.

. Under surface of the same test, natural size.

. Posterior view of ditto, showing the undulations of the base and the elevation

of the dorsal surface.

Lateral view of ditto, showing the great elevation of the anterior half of the test,
and the eccentricity of the vertex.

Tubercles from the base, with their hexagonal areas.

. Upper surface of another specimen in my collection.

. Two inter-ambulacral plates, a portion of the poriferous zones, and ambulacral area,

magnified four times.

. Apical disc and madreporiform tubercle, magnified. °

. Tubercles from the upper surface, greatly magnified.

Apical disc from a French specimen after M. Cotteau, showimg the size and arrange-
ment of the plates.

PL. XXXVIII

Printed by Hullmandel & Walton

Bone, del. et lith.

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PLATE XXXIX.
Pyeurus Painursu, Wright.
From the Coralline Oolite.

Pycurus Parisi, Wright, p. 403. Upper surface, natural size.

Posterior view of the same test, showing the depression of the upper surface and

the undulation of the base.

Two inter-ambulacral plates, a portion of the poriferous zones, and ambulacral area,

magnified three times.

/- A portion of an ambulacral area, with its poriferous zones, magnified eight times.

Pycaurus Havsmanni, Koch and Dunker, p. 405. Two of the inter-ambulacral
plates, a portion of the poriferous zones, and ambulacral area, magnified

three times.

PL

XX XIX

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PLATE XL.
Pyeurus Hausmannt, Koch and Dunker.
From the Coralline Oolite.

Pycurus Hausmannt, Koch and Dunker, p. 405. The upper surface restored, natural
size. Most of the adult specimens of this largest British Oolitic urchin
are fractured and distorted, but some of the smaller individuals show

the true outline of the test.

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SUPPLEMENT.

PLATE XLI.

. Nucrnorirus recuns, Edwards. he living representative of this group from
Australia, showing the test and spines copied from Professor Milne-
Edwards’ figure in the illustrated edition of Cuvier’s ‘Regne Animal
Zoophytes,’ tab. xiv, fig. 3.

. The anal aperture, and its surrounding anal plates.

. Pepina Smirnit, Mordes, p. 176. Upper surface of the test, natural size.

4. Inter-ambulacral plate, portion of the poriferous zones, and ambulacral area, magni-

fied three times.

‘Three pair of pores, greatly magnified.

. PsxupopiapEMA Lopatum, Wright. Fragments of tests, with spies, on a slab of

Lower Lias shale from Pinhay Bay.

Spine of the same, magnified.

. PyeasTer mEcastoma, Wright,n. sp. Upper surface, natural size.

6. Under surface of the same test, natural size.

Lateral view of ditto, ditto.

. Two inter-ambulacral plates, poriferous zones, and ambulacral areas, of another

specimen of the same species.

Apical disc of a small specimen of Pygaster megastoma, Wr.
Large spine of Diptociparis Wricutit, Desor.
Spine of Crparis pustuLata, Wright, with a portion greatly magnified.

Spine of Crparis.

lement

Supp

falton.

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Printed. by Hil

C.R: Bone, del et-Hth.

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a.

a.

b.

SUPPLEMENT.

PLATE XLII.

Ciparis Fownrr, Wright, p. 32. Test, with spines attached, of the natural size.

. Inter-ambulacral plate, zones, and ambulacral area, magnified.

Primary tubercle, magnified.
One of the jaws, magnified.
One of the primary spines, magnified twice.

One of the secondary spines, magnified three times.

Hypociyeus acaricirormis, Mordes. Upper surface, natural size, showing the
apical dise 2m satu.

Under surface of the same, natural size.

The apical disc of the same urchin, magnified twice.

Supplement

Printed by Hullmande! & Walton

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SUPPLEMENT.

PLATE XLITI.

. Pupina Suiruu, Forbes, p. 176. Upper surface, natural size.

Under surface, natural size, showing the mouth-opening.

Lateral view of the same test, natural size.

. Base of an ambulacral area, showing the crowding of the pores in the zones, magni-

fied four diameters.

Hemiciparis Brituensis, Wright (Supplement). Upper surface, natural size.

Lateral view of the same test, natural size.

. Two inter-ambulacral plates, a portion of the ambulacral area, and two poriferous

zones, magnified three and a half times.

Apical disc, magnified two diameters.
Hcuinosrissus Bropres, Wright, p. 353. Upper surface, natural size.

Ciypeus Provir, A/ecn, p. 361. A weathered portion of the upper surface of a
test. of this species, showing perforated tubercles on all the inter-ambu-
lacral and ambulacral plates, with the madreporiform body extending
over all the pieces of the apical disc, magnified three diameters.

Cuiyrrus Priori, A7lein, a portion of the upper surface of the test, highly magnified,
to show the perforations of the tubercles.

. Hererociparis Wicxenss, Wright (Supplement). Four rows of plates, natural

size.
One of the plates and primary tubercles, magnified three times.

A lateral view of one of the primary tubercles, highly magnified.

o upplem ent

C.R Bone. del. et hth

Printed by Hullmeandel & Walton.

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