MMH CR weirs tj BAF e ee EZ LILLE oy ae ae ve Sirtan hte Mice x o 2290Ss00 TOEO OU wv IOHM/18WN ws JOS Jb THE PEARLY NAUTILUS after Owen) Tt O00 fy a Lhe mapnite 6___TIts dorsul told | 000 Eatertor digitations é___ Nidametal Gland | p___ Tentacles pie akon Eve we Septa x Last (hamber Ga Shell muscle VT U_Stphor Ak__. Funnel TWLowry fe. “ VANUAL OF THE MOLLUSOA BEING A TREATISE ON RECENT AND FOSSIL SHELLS By S. P. WOODWARD, A.1.8., F.G.S. LATE ASSISTANT-PAL-ZONTOLOGIST IN THE BRITISH MUSEUM Storage FOURTH EDITION CH AN APPENDIX OF RECENT AND FOSSIL CONCHOLOGICAL DISCOVERIES by RAGPH TATE, A.L.S3e8".G.8. Ellustrated by A. N. WATERHOUSE AND JOSEPH WILSON LOWRY LONDON Pree bY LOCKWOOD AND .€@. 7, STATIONERS’ HALL COURT, LUDGATE HILL 1880 i * PREFACE. Tuts Manual, which for six years occupied the Author’s unceasing attention, was intended as a companion to Gen. Portlock’s Geology ; and the desire to make it worthy of that association led to an amount of labour and expense which only a very extended circulation will repay. The plan and title were taken from the ‘‘ Manuel des Mollusques”? of M. Sander Rang, incomparably the best work of its kind—for an acquaintance with which the author was indebted to his friend and master, Wirtram LonspsLE— the founder of the ‘‘ Devonian System” in Geology. On the subject of classification and nomenclature the Author followed the advice and example of his former colleague in the Geological Society, the late Prof. Epwarp Forszs; without whose approval he seldom added to, or deviated from, the practice and plan of the ‘‘ History of British Mollusca.” That he was right in taking this course, has been sanctioned by the highest authority in this country ;—since the same scheme has been employed by Prof. Owrn in the Hunterian Lectures and Catalogue. It has also been adopted by Dr. E. Batrovurin the Madras Museum; by the Rev. Prof. Henstow, in his Report to the British Association on the Formation of Typical Collections; and by Prof. Morris in his Catalogue of British Fossils. ; It was the writer’s desire, by abstaining from the intro- b av PREFACE. duction of personal and peculiar views, and by adhering to whatever was well established and sanctioned by the best examples, to. make the work suitable for the use of Natural History Classes in the Universities. To facilitate reference, and meet the most general require- ments, the number of large groups and genera of shells has been restricted as much as possible, and those less important or less understood, have been treated as ‘‘sub-genera.” sees ene 81 XV. Magellanic Province: Falkland Islands .......... 82 Vi, Patagonian Provmce ........ 0.0006 oss ee 83 VEL Caribbean Province ........3..-0.05 ++). 84 XVIII. Transatlantic Province ....../...0.0088e=eee , 85 Lanp Recions.—Distribution of land and fresh-water shells; genera of the Old and New World; arctic regions ........ 86 i. Germanic Region > Siberia ........00-can ss ee 89 2. Lusitanian Region: Mediterranean Islands; Madeira, Azores, Canaries, Cape de Verdes, Ascension .... 91 S. Helena, ‘Tristan d’Acunha........5:.- sss eee 96 o. African Region... os.ess eens cece seen tne ay, 4. Cape Region ... 0.0.0 .500.s0 0 een nes oe rn 97 5. Yemen—Madagascar: Comoro Islands, Seychelles, Mauritius, Bourbon, Rodriguez ..........++..-+: 98 6. Indian Region: Ceylon .. ss <. + a:)5 ee =e 99. G China and Japan .....2. + «00% > «cw ¢5\e aie 101 S. Philippe Islands ..-..... 22. s=2s0smee ee ea 101 PO RAIUE Si ctslis 5 «> os << woken Pris on 102 DUE COLDCO’ oc. bas 55's 52 MPT CONTENTS. ix PAGE 11. Papua and New Ireland ...... Waiernie-diewneee sets old MemeeENGPANIAN. FRCGTON 6 oi. coo vse ve v's sane Seacvaee 103 fee poursAustraha and-. 5 supe ee ee 805 Fam. VI. Cyelostomide.—Cyclostoma, Ferussina?, Cyclo- phorus, Pupina, Helicina, Stoastoma ...............se0. 306 Fam. VII. Aciculide.—Acicula, Geomelania .............. 310 OrpER III. OPpisTHo-BRANCHIATA ....00. ee 311 SECTION A. “I'ECTI-BRANCHIATA,. < . i000000 000 sues 6s 0 eee 312 Fam. I. Tornatellide.—Tornatella, Cinulia, Ringicula, Glo- biconcha, Varigera, Tylostoma, Pterodonta ?, Tornatina?.. 312 Fam. II. Bullide—Bulla, Acera, Cylichna, Kleinella?, Amphisphyra, Buccinulus, Aplustrum, Scaphander, Phi- line, Doridium, Gastropteron, Physema ................. 315 Fam. III. Aplysiade.—Aplysia, Dolabella, Stylocheilus, Dolabrifera, Siphonopyge, Notarchus, Icarus, Lobiger.... 320 Fam. IV. LPleurobranchide. — Pleurobranchus, Postero- branchzea, Runcina, Neda, Susaria, Umbrella, Tylodina .. 322 Fam. V. Phillidiade.—Phyllidia, Fryeria, Hypobranchiea, Diphyidiiay,. 0.5... ose ee Gied we wie ok od eee te er 324 Srerion B. NUDIBRANCHIATA 6.66 oc0 cc sce0 coe sm ecie eeenn 325 Fam. VI. Doride.—Doris, Heptabranchus, Hexabranchus, Atagema, Actinocyclus, Chromodoris, Asteronotus, Glos- sodoris, Goniodoris, Triopa, Hgirus, Thecacera, Polycera, Idalia, Ancula, Ceratosoma, Trevelyana, Crimora, Pelagella, Gymnodoris, Acanthodoris, Casella, Brachychlamis ...... 328 Fam. VII. TZritoniade.—Tritonia, Scyllea, Tethys, Bornella, Dendronotus, Doto, Gellina, Melibcea, Lomanotus ...... 332 Fam. VIII. _olide.—Molis, Glaucus, Fiona, Embletonia, Calma, Favorinus, Galvina, Cuthonia, Filurus, Proctonotus, Antiopa, Hermea, Alderia, Chior@ra ............seeeee 335 Fam. III. Mytilide.—Mytilus, Myalina, Modiola, Hippomya, Re ea tas Bly aid wea sa lu oa 'bi9 + dota a hm oe are le eS CONTENTS. PAGE Fam. IX. Phyllirhoide.—Phyliirhoe .................... 339 Fam. X. Llysiade.—Elysia, Acteonia, Cenia, Limapontia, Rar RSS eRe 70S hd it os ve ae brdalelndas a0 sven de 339 SemmmlW. NvGLEGERANGHIATA . <4... 2.20. . c ss sb veus cher 340 Fam. I. rolide.—Firola, Carinaria, Cardiapoda ........ 342 Fam. II. Saw yee eee weno 351 Peeanee TEL PUN OSOMATA 6 os a 054s woe ecctee ieee eue seas 353 Fam. III. Clide—Clio, Pneumodermon, Pelagia, Cymo- EME ot es sits sf Poke e Conus teat 353 CHAPTER III. RE UESHACTIOP ODA. 5 ocioco'o os sk aioe ee ee ee oe we mareres biaaee’ 354 Fam. I. Terebratulide.—Terebratula, Terebratella, Argiope, See AIT REINS OCCPRALGS Ff. Ss iss Fs Spek wre vee es ee he 363 Fam. II. Spiriferide.—Spirifera, Athyris, Retzia, Uncites.. 371 Fam. III. Rhynchonellide.—Rhynchonella, Pentamerus, ME MOEN y e022 Le So eis sain cis oo ain & wlaeca abaie tanh eee 379 Fam. IV. Orthide.—Orthis, Strophomena, Davidsonia, Cal- MME ore So ns Sng A Daa ial ca a war eG A Spe! Satershaie eee SUE: 379 Fam. V. Productide.—Productus, Strophalosia, Chonetes ..- 383 ee Crea. =—OTraATa 0's oon ano 0 sss lows onesie 386 Fam. VII. Discinide.—Discina, Siphonotreta ............ 388 Fam. VIII. Lingulide.—Lingula, Obolus ..........02 00. . 390 CHAPTER IV. a a CRRA TEIIS ERED AS Fic kL oo, Vela mia bain bia awh wlejeGid epee aie ¥ ine oe 393 Steam Ae VAGIPHONIDA S200. 6 Cocoa a ee oe ee eves epee S 406 Fam. I. Ostreide.—Ostrea, Anomia, Placuna, Pecten, Lima, Siparmiylniss PU CAGUI AS. oc ce ia ce eee koe tos os wells ow omere 407 Fam. II. Aviculide.—Avicula, Posidonomya, Aviculo-pecten, Gervillia, Perna, Inoceramus, Pinna..........-++see eee 415 XIV CONTENTS. Fam. IV. Arcade.—Arca, Cucullea, Pectunculus, Limopet = Nucula, Isoarca, Leda, Solenella, Solemya.............. 424 Fam. V. Trigoniade.—Trigonia, Myophoria, Axinus, Cur- fonotus, Pseudaxinus, Lyrodesma .....»..ss ssn 430 Fam. VI. Unionide.—Unio, Castalia, Anodon, Iridina, Mycetopus, Attheria, Milleria~ .......+ «+ messi 432 Section B. Srenonrpa: Integro-pallialia ............ ee00 sere 436 Fam. VII, Chamide.—Chama, Diceras, Requienia ..... ey! Fam. VIIl. Hippuritide.Hippurites, Radiolites, Capri nella, Caprina, Caprotina... ..........s- sass or. 440 Fam. IX. Tridacnide.—Tridacna ..... 0.00706 see 451 Fam. X. Cardiade.—Cardium, Conocardium,............: 453 Fam. XI. Lucinide.—Lucina, Corbis, Tancredia, Diplo- donta, Ungulina, Kellia, Montacuta, Lepton, Galeomma 4&5 Fam. XII. Cycladide.—Cyclas, Cyrena, Cyrenoides ...... 461 Fam. XIII. Cyprinide.—Cyprina, Circe, Astarte, Gouldia, Crassatella, Isocardia, Cypricardia, Pleurophorus, Cardilia, Megalodon, Pachydomus, Pachyrisma, Opis, Cardinia. Myoconcha, Cardita, Verticordia ...... 0... >«sseaeee 463 Section C. Srenonma; Sinu-pallialia ..............++++ sees 472 © Fam. XIV. Veneride.—Venus, Cytherea, Meroe, Trigona, Artemis, Lucinopsis, Tapes, Venerupis, masts Glau- COMYS 2.0550 oct did dn eis'ele die ops ce ws ¥ epaulets 47% Fam. XV. Mactride.—Mactra, Harvella, Gnathodon, Lu- traria, Anatinella 05.02... s00ad0 0000s 0s 12 477 Fam. XVI. Tellinide.—Tellina, Gastrana, Capsula, Quen- stedtia, Psammobia, Sanguinolaria, Semele, Mesodesma, Ervilia, Donax, Galatea. .......000d.0s 00055 2 479 Fam. XVII. Solenide.—Solen, Cultellus, Solecurtus...... 486 Fam. XVIII. Myacide.—Mya, Corbula, Nexra, Thetis, Panopsa, Glycimeris ..... 6 Bes os 'eiclnle wu ae oes 489 Fam. XIX. -Anatinide.—Anatina, Ribeiria, Thracia, Phola- domya, Myacites, Ceromya, Cardiomorpha, Edmondia, Lyonsia, Pandora, Myadora, Myochama, Chamostrea .... 494 Fam. XX. Gastrochenide.—Gastrochena, Saxicava, Ciava- gella, Aspergillum, Humphreyia . ..........0e-eeeeees 500 Fam. XXI. Pholalide.—Pholas, Pholadidea, Xylophaga, Teredo. eeeeeoevoeoevseeenseeesaevreeseeereeeeeereeeeeeeee see ee se 505 fs MANUAL OF THE MOLLUSCA, PA Pade CHAPTER I. ON THE POSITION OF THE MOLLUSCA IN THE ANIMAL KINGDOM. ALL known animals are constructed upon five different types, and constitute as many natural divisions or sub-kingdoms. 1. The highest of these groups is separated from the next below it by a sharp line of distinction. In it the main mass of the neryous system is placed on the dorsal side of the body, and is in no instance pierced by the alimentary canal. It is separated from the alimentary canal by a partition, which in most cases is bony, and divided into separate parts, known as vertebra; while in a few it is cartilaginous, and not divided into distinct parts. Vertebre are a common feature amongst the Vertebrata, as this sub-kingdom is called; but they do not form an essential characteristic, as the name might seem to imply. Distinct organs are devoted to the functions of respiration and cireu- lation; the sexes are generally distinct; each individual is generally developed from a single egg. Blood red. 2. In the second sub-kingdom, or Mollusca, which is well exemplified by the common garden snail, the nautilus, and the oyster, the soft parts are in most cases protected by an external sheli, which is harder than the bones of the vertebrates, and the covering of the crab and lobster. It consists almost entirely of carbonate of lime, while the bones of the vertebrates contain a large proportion of phosphate of lime. The shells of many of the Brachiopoda, such as Lingula, and of a few of the Pteropoda, B 2 MANUAL OF THE MOLLUSCA. such as Conularia, are rich in the phosphate of lime. The digestive cavity 1s completely separated from the walls of the body. The nervous system consists of three pairs of ganglia, except in the Brachiopoda, and these neryous centres are very much scattered. Hence Professor Owen has proposed the term Heterogangliata for the great group of Mollusca. The end of the alimentary canal nearest the mouth is surrounded by the eanglia which supply the foot and head. 3. The various tribes of insects, spiders, crabs, starfishes, echinoderms, entozoa, and worms, haye no internal skeleton ; but to compensate for it, their outer integument is sufficiently hard to serve at once as a support, a covering, and a defence for the soft parts. This external armature, lke the bodies and limbs which it covers, is divided into segments or joints, which well distinguishes the members of this group from the others. The propriety of arranging worms with insects will be seen, if it be remembered that even the butterfly and bee commence existence in a very worm-like form. This division of jointed animals bears the name of the Annulosa. The neryous system consists of ganglia arranged in pairs in the middle line of the body. From this equal lateral development cf the neryous centres Professor Owen calls the groun Homogungliata. The nervous system is traversed by the alimentary canal. The radiated animals form a part of this sub-kingdom. 4, The next sub-kingdom comprises most of the polypes, such as sea-anemones, the fresh-water hydra, and corals, in which the general cavity of the body communicates freely with that of the digestive apparatus, on which account they are called Coelenterata. The soft parts forming the body wall are composed of two distinct membranes; there is no heart; no apparent special respiratory organ; and in most cases very shght traces of a nervous system. 5. All the animals not combined in the above groups, such as thé sponges, the foraminifera, and a large proportion of the microscopic animalcules, form the last sub-kingdom, named Protozoa. They are characterised by a general absence of any special organ. There seems to be a much closer relationship between the molluscan and the protozoic sub-kingdoms than between the molluscan and any of the others. It is always easier to pass from the highest part of a sub-kingdom downwards in the scale of nature than to pass upwards. ‘Thus we can step from one form to another without meeting with any marked distinction from the Cephalopods to the Brachiopods, and from them to the CLASSES OF THE MOLLUSCA. 3 Protozoa. In the same way we can pass from the highest of the Annulosa to the Protozoa. But we cannot find any continuous succession of adult forms which will connect the Annulosa with the Mollusca, or the Mollusca with the Vertebrata. Much use is made of the terms high and low in speaking of animals; and it is important to bear in mind that they are by no means intended to imply that there is any difference in the degree of perfection, or that one animal is less fitted to subserye the purposes of life than another. By an animal of a low organisation is simply meant one in which all the functions of life are carried on by means of a few organs. The greater the number of organs that are set apart to perform special functions the higher is the animal said to be. The evidence afforded by geological researches seems to show that the leading types of animal structure have existed from a comparatively early period in the history of the globe; and that all forms which haye left any indications of their existenco belong to one or other of these types. The oldest fossils known at the present time belong to the Protozoa; but next to them come the Mollusca. By adding to the living population of the world, those forms which peopled it in times long past, we may arrive at some dim conception of the great scheme of the animal kingdom. And if at present we see not the limits of the temple of nature, nor fully comprehend its design,—at least we can feel sure that there is a boundary to this present order of things; and that there has been a plan, such as we, from our mental constitu- tion, are able to appreciate, and to study with ever-increasing admiration. CLASSES OF THE MOLLUSGA. This sub-kingdom consists of two great groups, viz., tho mollusca proper and the molluscoida. The mollusca are animals with soft bodies, enveloped in a muscular skin, and usually protected by a uniyalve or bivalve shell. That part of thigir integument which contains the viscera and secretes the shell, is termed the mantle ; in the univyalves it takes the form of a sac, with an opening in front, from which the head and locomotiye organs project: in the bivalves it is divided into two lobes. The uniyalye mollusca are encephalous, or furnished with a distinct head; they have eyes and tentacula, and the mouth 1 armed either with jaws or with tooth straps.* Cuvier has * One of the drawbacks to the study of mollusca is the prevalence of such teims 23 jaws, arms, feet, &c. The reader must not suppose that the parts so designated ars B2 a 4 MANUAL OF THE MOLLUSCA. divided them into three classes, founded on the modifications of their feet, or principal locomotive organs. 1. The cuttle-fishes constitute the first class, and are termed evarent sive tole] Fig. 1.* Oral aspect of a Cephalopod. Cephalopoda,t because their feet, or more properly arms, are so attached to the head as to form a circle round the mouth. 2. In the Gasteropoda,} or snails, the under side of the body Fig, 2. A Gasteropod.§ Fig. 3. A Pteropod. | forms a single muscular foot, on which the animals creep or glide. homologous in the vertebrata and in the mollusca. When applied to the latter, the terms are vague and indefinite in meaning. * Fig. 1. Loligo vulgaris, Lam.}. From a specimen taken off Tenby, by J. S. Bowerbank, Esq. The mandibles are seen in the centre, surrounded by the circular lip, the buccal membrane (with two rows of small cups on its lobes), the eight sessile arms, and the long pedunculated tentacles (t), with their enlarged extremities or clubs (e). The dorsal arms are lettered d, the funnel f. ¢ From cephale, the head, and poda, feet. See the frontispiece and pl. I. t Gaster, the under side of the body. § Fig. 2. Helix desertorum, Forskal. From a living specimen in the British Museum, March, 1850. { Fig. 3. Hyalea tridentata, Lam,, from Quoy and Gaimard, ' CLASSES OF THE MOLLUSCA. 5 3. The Pteropoda * inhabit the sea only, and swim with a pair of fins, extending outwards from the sides of the head. The other mollusca are acephalous, or destitute of any distinct head; they are all aquatic, and most of them are attached, or haye no means of moving from place to place. They are divided into three classes, characterised by modifications in their breath- ing-organ and shell. 4. The Brachiopoda + are bivalves, haying one shell placed on the back of the animal, and the other in front; they take their name from two long ciliated arms, developed from the sides of Figs. 4,5, 6. Brachiopoda.} the mouth, with which they create currents that bring them food. These arms were formerly supposed to take the place of the feet in the preyiously-mentioned classes. They are, how- ever, essentially breathing organs, and consequently the term Brachionobranchia (arm-breathers) has been proposed for the erroneous one of Brachiopoda (arm-footed). & The Lamellibranchiata,§ or ordinary bivalves (like the oyster), breathe by two pairs of gills, in the form of flat mem- branous plates, attached to the mantle; one valve is applied to the right, the other to the left side of the body. This class is sometimes called Conchifera. The Tunicata have no shell, but are protected by an elastic, gelatinous tunic, with two orifices; the breathing organ takes the form of an inner tunic, or of a riband stretched across the internal cavity. These together with the Polyzoa, and perhaps * Pteron, a wing. + Brachion, an arm. t Fig. 4. (3.) Rhynchonella psittacea, Chem. sp., dorsal valve, with the animal (after Owen). 5,6, Zerebratula australis, Quoy. From specimens collected by Mr. Jukes. (2.) Ideal side view of both valves (f, the cardinal muscles, by which the valves are opened). (1.) Dorsal valve. These woodcuts have been kindly lent by Mr. J. E. Gray. §$ Lamellibranchiata, plate-gilled. 6 MANUAL OF THE MOLLUSCA. the Brachiopoda, form the sub-class of Molluscoida. In the first edition the T'wnicata were described in detail, but they are omitted in this for reasons stated in the preface. Five of these modifications of the molluscan type of organi- sation were known to Linnzeus, who referred the animals of all his genera of shell-fish to one or other of them;* but unfortu- nately he did not himself adopt the truth which he was the first to see; and here, as in his botany, employed an artificial, in preference to a natural method. The systematic arrangement of natural objects ought not, however, tobe guided by conyenience, nor ‘‘ framed merely for the purposes of easy remembrance and communication.” The Fig. 7. A Bivalve.+ true method must be suggested by the objects themselyes, by their qualities and relations ;—it may not be easy to learn,—it. may require perpetual modification and adjustment,—but inas- much as it represents the existing state of knowledge it will aid * The Linnean types were—Sepia, Limax, Clio, Anomia, Ascidia. Terebratula was inciuded with Anomia, its organisation being unknown. + Mya truncata, L.}. From Forbes and Hanley. t Ascidia mentula, Miill. Ideal representation; from a specimen dredged by Mr Bowerbank, off Tenby. HABITS AND ECONOMY OF THE MOLLUSCA. { in the UNDERSTANDING of the subject, whereas a ‘‘dead and arbitrary arrangement” is a perpetual bar to advancement, ‘*containing in itself no principle of progression.”’ (Colertdge.) HABITS AND ECONOMY OF THE MOLLUSCA. Eyery liying creature has a history of its own; each has characteristics by which it may be known from its relatives; each has its own territory, its appropriate food, and its duties to perform in the economy of nature. Our present purpose, however, is to point out those circumstances, and trace the progress of those changes which are not peculiar to individuals or to species, but have a wider application, and form the history of a great class. In their infancy the molluscous animals are more alike, both in appearance and habits, than in after life; and the fry of the aquatic races are almost as different from their parents as the caterpillar from the butterfly. The analogy, however, is reversed in one respect ; for whereas the adult shell-fish are often seden- tary, or ambulatory, the young are all swimmers; so that by means of their fins and the oceun-currents, they travel to long distances, and thus diffuse their race as far as a suitable climate and conditions are found. Myriads of these little voyagers drift from the shores into the open sea and there perish; their tiny and fragile shells become part of a deposit constantly accumulating, even in the deepest parts of the sea. Some of these little creatures shelter themselves beneath the shell of their parent for a time, and many can spin silken threads with which to moor themselves, and avoid being drifted away. They all havea protecting shell, and even the young bivalves haye eyes at this period of their lives, to aid them in choosing an appropriate locality. After a few days, or even less, of this sportive existence, the sedentary tribes settle in the place they intend to occupy during the remainder of their lives. The tunicary cements itself to rock or sea-weed ; the ship-worm adheres to timber, and the ~xholas and lithodomus to limestone rocks, in which they soon excayate a chamber which renders their first means of anchorage unnecessary. The mya and razor-fish burrow in sand or mud; the mussel and pinna spin a byssus; the oyster and spondylus attach themselves by spines or leafy expansions of their shell; the brachiopoda are all fixed by similar means, and eyen some of the gasteropods become voluntary prisoners, as the hipponyx and vermetus. 8 MANUAL OF THE MOLLUSCA. Other tribes retain the power of travelling at will, and shift their quarters periodically, or in search of food; the river- mussel drags itself slowly along by protruding and contracting its flexible foot; the cockle and trigonia have the foot bent, enabling them to make short leaps; the scallop (pecten opercu- laris) swims rapidly by opening and shutting its tinted valves. Nearly all the gasteropods creep lke the snail, though some are much more active than others; the pond-snails can glide along the surface of the water, shell downwards; the nucleobranchs and pteropods swim in the open sea. The cutile-fish haye a strange mode of walking, head downwards, on their outspread arms; they can also swim with their fins, or with their webbed arms, or by expelling the water forcibly from their branchial chamber; the calamary can eyen strike the surface of the sea with its tail, and dart into the air like the flying-fish.—( Owen.) By these means the mollusca haye spread themselves over every part of the habitable globe; every region has its tribe; every situation its appropriate species; the land-snails frequent moist places, woods, sunny banks and rocks, climb trees, or burrow in the ground, The air-breathing limneids live in fresh-water, only coming occasionally to the surface; and the auriculas live on the sea-shore, or in salt-marshes. In the sea each zone of depth has its molluscous fauna. The limpet and periwinkle live between tide-marks, where they are left dry twice a day; the trochi and purpure are found at low water, amongst the sea-weed; the mussel affects muddy shores, the cockle rejoices in extensive sandy flats. Most of the finely- coloured shells of the tropics are found in shallow water, or amongst the breakers. Oyster-banks are usually in four or five fathoms water; scallop-banks at twenty fathoms. The terebratule are found at still greater depths, commonly at fifty fathoms, and sometimes at one hundred fathoms, eyen in Polar seas. The fairy-like pteropoda, the oceanic snail, and multi- tudes of other floating molluscs, pass their lives on the open sea, for ever out of sight of land; whilst the litiopa and scyliea follow the gulf-weed in its voyages, and feed upon the green delusive banks. The food of the mollusca is either vegetable, infusorial, or animal. All the land-snails are vegetable-feeders, and their depredations are but too well known to the gardener and farmer ; many a crop of winter corn and spring tares has been wasted by the ravages of the ‘‘small grey slug.” They haye their likings, too, for particular plants, most of the pea-tribe and cabbage-tribe are fayourites, bnt they hold white mustard HABITS AND ECONOMY OF THE MOLLUSCA. 9 in abhorrence, and fast or shift their quarters while that crop is onthe ground.* Some, like the ‘‘ cellar-snail,” feed on crypto- gamic vegetation, or on decaying leaves; and the slugs are attracted by fungi, or any odorous substances. The round- mouthed sea-snails are nearly all vegetarians, and consequently limited to the shore and the shallow waters in which sea-weeds grow. Beyond fifteen fathoms, almost the only vegetable pro- duction is the nullipore; but here corals and horny zoophytes take the place of alge, and afford a more nutritious diet. The whole of the bivalves, and other headless molluscs liye on infusoria, or on microscopic plants, brought to them by the current which their ciliary apparatus perpetually excites; such, too, must be the sustenance of the magilus, sunk in its coral bed, and of the calyptrea, fettered to its birth-place by its cal- careous foot. The carnivorous tribes prey chiefly on other shell-fish, or on zoophytes; since, with the exception of the cuttle-fishes, their organisation scarcely adapts them for pursuing and destroying other classes of animals. One remarkable exception is formed by the stilifer, which lives parasitically on the star-fish and sea- urchin; and another by the ftestacella, which preys on the common earth-worm, following it in its burrow, and wearing a buckler, which protects it in the rear. Most of the siphonated uniyalyes are animal-feeders; the carrion-eating stromb and whelk consume the fishes and other creatures, whose remains are always plentiful on rough and rocky coasts. Many wage war on their own relatives, and take them by assault; the bivalves may close, and the oper- culated nerite retire into his home, but the enemy, with rasp- like tongue, armed with siliceous teeth, files a hole through the shell,—vyain shield where instinct guides the attack! Of the myriads of small shells which the sea heaps up in eyery sheltered ‘‘ ness,” a large proportion will be found thus bored by the whelks and purples; and in fossil shell-beds, suck as that in the Touraine, nearly half the bivalves and sea-snails are perforated,—the relics of antediluyian banquets. This is on the shore, or on the bed of the sea; far away from land the carinaria and firola pursue the floating acalephe ; and the argonaut, with his relative the spirula, both carnivorous, are found in the “high seas,” in almost every quarter of the globe. The most active and rapacious of all are the calamaries * Dilute lime-water and very weak alkaline solutions are more fatal to snails than even salt. BS 10 MANUAL OF THE MOLLUSCA. and cuttles, who vindicate their high position in the naturalists’ “system,” by preying even on fishes. As the shell-fish are great eaters, so in their turn they afford food to many other creatures; fulfilling the universal law of eating and being eaten. Civilised man still swallows the oyster, although snails are no longer reckoned ‘‘a dainty dish;” mussel, cockles, and periwinkles are in great esteem with children and the other unsophisticated classes of society ; and so are scallops and the haliotis, where they can be obtained. Two kinds of whelk are brought to the London market in great quantities; and the arms of the cuttle-fish are eaten by the Neapolitans, and also by the East Indians and Malays. In seasons of scarcity, vast quantities of shell-fish are consumed by the poor inhabitants of the Scotch and Ivish coasts.* Still more are regularly collected for bait; the calamary is much used in the cod-fishery, off Newfoundland, and the limpet and whelk on our own coasts. Many wild animals feed on shell-fish; the rat and the raccoon seek for them on the sea-shore when pressed by hunger; the South American otter, and the crab-eating opossum constantly resort to salt-marshes, and the sea, in order to prey on the mollusca ; the great whale lives habitually on the small floating pteropods ; sea-fowl search for the littoral species at every ebbing tide; whilst, in their own element, the marine kind are perpetually deyoured by fishes. The haddock is a ‘‘ great conchologist ;”’ and some rare northern sea-shells haye been rescued, unbroken, from the stomach of the cod; whilst even the strong valves of the cyprina are not proof against the teeth of the cat-fish (anarhicas). They even fall a prey to animals much their inferiors in sagacity; the star-fish swallows the small bivalve entire, and dissolyes the animal out of its shell; and the bubble-shell (philine), itself predacious, is eaten both by star-fish and sea- — anemone (actinia). The land-snails afford food to many birds, especially to the thrush tribe; and to some insects, for the luminous larva of the glow-worm lives on them, and some of the large predacious beetles (e.g., carabus violaceus and goerius olens), occasionally kill siugs. The greatest enemies of the mollusca, however, are those of * See Hugh Miller’s “Scenes and Legends of the North of Scotland.” The Ajok- kenmodings, or kitchen refuse-heaps, which have been found so abundantly in Den- mark, Scotland, New Zealand, and elsewhere, are sometimes hundreds of yards in length, and composed almost entirely of shells, HABITS AND ECONOMY OF THE MOLLUSCA, 1] their own nation. Scarcely one-half the shelly tribes graze peacefully on sea-weed, or subsist on the nutrient particles which the sea itself brings to their mouths; the rest browse on liying zoophytes, or prey upon the vegetable-feeders. Yet in no class is the instinct of ‘‘ self-preservation”’ stronger, nor the means of defence more adequate; their shells seem expressly given to compensate for the slowness of their move- ment, and the dimness of their senses. The cuttle-fish escapes from attack by swimming backwards and beclouding the water with an inky discharge; and the sea-hare (aplysia) pours out, when irritated, a copious purple fluid, formerly held to be poisonous. Others rely on passive resistance, or. on conceal- ment, for their safety. It has been frequently remarked that molluses resemble the hue and appearance of the situation they frequent; thus, the limpet is commonly overgrown with balani and sea-weed, and the ascidian with zoophytes, which form an effectual disguise; the lima and modiola spin together a screen of grotto-work. One ascidian (a. cochligera) coats itself with shell-sand, and the carrier-trochus cements shells and corals to the margin of its habitation, or so loads it with pebbles, that it looks like a little heap of stones. It must be confessed that the instincts of the shell-fish are of a low order, being almost limited to self-preservation, the escape from danger, and the choice of food. An instance of something like social feeling has been obseryed in a Roman snail (helix pomatia), who, after escaping from a garden, re- turned to it in quest of his fellow-prisoner ;—but the accom- plished naturalist who witnessed the circumstance hesitated to record a thing so unexampled. The limpet, too, we learn from the observations of Mr. George Roberts, of Lyme Regis, is fond of home, or at least possesses a knowledge of topography, and returns to the same roost after an excursion with each tide. Professor Forbes has immortalised the sagacity of the razor- fish, who submits to be salted in his hole, rather than expose himself to be caught, after finding that the enemy is lying in wait for him. On the other hand, Mr. Bowerbank has a curious example of ‘‘instinct at fault,’ in the fossil spine of a sea- urchin, which appears to haye been drilled by a carniyorous gasteropod., We have spoken of shell-fish as articles of food but they haye other uses, even to man; they are the toys of children, who hear in them the roaring of the sea; they are the pride of ** collectors ”’—whose wealth is in a cone or ‘‘ wentle-trap ;” * * The extravagant prices that have been given for rare shells are less to be regretted, 12 MANUAL OF 1MHE MOLLUSCA. and they are the ornaments of barbarous tribes. The Friendly- Islander wears the orange-cowry as a mark of chieftainship (Stutchbury), and the New Zealander polishes the elenchus into an ornament more brilliant than the ‘‘ pearl ear-drop” of classical or modern times. (Clarke.) One of the most beautiful substances in nature is the shell-opal, formed of the remains of the ammonite. The forms and colours of shells (as of all other natural objects), answer some particular purpose, or obey some general law; but besides this, there is much that seems specially intended for our study, and calculated to call forth enlightened admiration. Thus the tints of many shells are concealed during life by a dull external coat, and the pearly halls of the nautilus are seen by no other eyes than ours. Or descending to mere ‘‘utility,” how many tracts of coast are destitute of limestone, but abound in shell-banks which may be burned into lime; or in shell-sand, for the use of farmers.* Not much is known respecting the individual duration of the shell-fish, though their length of life must be very variable. Many of the aquatic species are annuals, fulfilling the cycle of their existence in a single year; whole races are entombed in the wintry tide of mud that grows from year to year in the beds of rivers, and lakes, and seas; thus, in the Wealden clay we find layer above layer of small river-snails, alternating with thin strata of sediment, the index of immeasurably distant years. Dredgers find that whilst the adults of some shell-fish can be taken at all seasons, others can be obtained late in the autumn or winter only; those caught in spring and summer being young, or half-grown; and itis a common remark that dead shells (of some species) can be obtained of a larger size than any that we find alive, because they obtain their full growth at a season when our researches are suspended. Some species require part of two years for their full development ; the young of the doris and eolis are born in the summer time, in the warm shallows, near the shore; on the approach of because they have induced voyagers to collect. Mere shell-collecting, however, is no more scientific than pigeon-fancying, or the study of old china. For educational pur- poses the best shells are the types of genera, or species which illustrate particular points of structure ; and, fortunately for students, the prices have been much diminished of late years. A Carinaria, once “ worth 100 guineas” (Sowerby), is now worth 1s. only ; a wentle-trap which fetched 40 guineas in 1701 (Rumphius) was worth only 20 guineas in 1753, and may now be had for 5s. The Conus gloria-maris has fetched £50 more than once, and Cyprea umbilicata has been sold for £30. * Shell-sand is only beneficial on peaty soils, or heavy clay land. It sometimes hardens into limestone, as on the coast of Devon; and at Guadaloupe, where it con- tains littoral shells and human skeletons of recent date, HABITS AND ECONOMY OF THE MOLLUSCA. 13 winter they retire to deeper water, and in the following spring return to the tidal rocks, attain their full growth early in the summer, and after spawning-time disappear. The land-snails are mostly biennial ; hatched in the summer and autumn, they are half-grown by the winter time, and acquire their full growth in the following spring or summer. In confinement, a garden-snail will live for six or eight years; but in their natural state it is probable that a great many die in their second winter, for clusters of empty shells may be found, adhering to one another, under ivied walls, and in other sheltered situations; the animals haying perished in their hybernation. Some of the spiral sea-shells live a great many years, and tell their age in a very plain and interesting man- ner, by the number of fringes (varices) on their whorls; the contour of the ranelia and murex depends on the regular re- currence of these ornaments which occur after the same inter- vals in well-fed individuals, as in their less fortunate kindred. The ammonites appear by their varices, or periodic mouths (Pl. III., fig. 3), to have lived and continued growing for many years. Many of the bivalves, like the mussel and cockle, attain their full growth in a year. The oyster continues enlarging his shell by annual “shoots,” for four or five years, and then ceases to grow outwards; but very aged specimens may be found, espe- cially in a fossil state, with shells an inch or two in thickness. The giant-clam (tridacna), which attains so large a size that _ poets and sculptors haye made it the cradle of the sea-goddess, must enjoy an unusual longevity; living in the sheltered lagoons of coral islands, and not discursive in its habits, the corals grow up around until it is often nearly buried by them ; but although there seems to be no limit to its life (though it may liye a century for all that we know), yet the time will probably come when it will be overgrown by its neighbours, or choked with sediment. The fresh-water molluscs of cold climates bury themselves during winter in the mud of ponds and rivers; and the land- snails hide themselyes in the ground, or beneath moss and dead leayes. In warm climates they become torpid during the hottest and driest part of the year. Those genera and species which are most subject to this ‘summer sleep” are remarkable for their tenacity of life; and numerous instances haye been recorded of their importation _ from distant countries in a living state. In June, 1850, a liying pond-mussel was sent to Mr. Gray from Australia, which 14 MANUAL OF THE MOLLUSCA. had been more than a year out of water.* The pond-snails (ampullarice) have been found alive in logs of mahogany from Honduras (Mr. Pickering}; and M. Caillaud carried some from Egypt to Paris packed in saw-dust. Indeed, it is not easy to ascertain the limit of their endurance; for Mr. Laidlay having placed a number in a drawer for this purpose, found them alive after five years, although in the warm climate of Calcutta. The cyclostomas, which are also operculated, are well known to survive imprisonments of many months; but in the ordinary land- snails such cases are more remarkable. Some of the large tropical bulimi, brought by Lieutenant Graves from Valparaiso, revived after being packed, some for thirteen, others for twenty months. In 1849 Mr. Pickering receiyed from Mr. Wollaston a basket-full of Madeira snails (of twenty or thirty different species), three-fourths of which proved to be alive after several months’ confinement, including a sea yoyage. Mr. Wollaston has himself told us that specimens of two Madeira snails (helix paptlio and tectiformis) survived a fast and imprisonment in pill-boxes of two years and a half, and that a large number of the small helix turricula, brought to England at the same time, were all living after haying been enclosed in a dry bag for a vear and a half. But the most interesting example of resuscitation occurred to a specimen of the Desert snail, from Egypt, chronicled by Dr. Baird.+ This individual was fixed to a tablet in the British Museum on the 25th of March, 1846; and on the 7th of March, 1850, it was observed that he must haye come out of his shell in the interval (as the paper had been discoloured, apparently in his attempt to get away); but finding escape ieee had again retired, dlosae his aperture with the usual glistening lr: this led to his immersion in tepid water and maryellous recoyery. Advantage was taken of this circumstance for making a sketch of the living animal (Fig. 2). The permanency of the shell-bearing races is effectually pro- vided for by their extreme fecundity; and though exposed to a hundred dangers in their early life enough survive to re-people the land and sea abundantly. The spawn of a single doris may contain 600,000 eggs (Darwin); a river-mussel has been esti- mated to produce 300, 000 young in one season, and the oyster cannot be much less prolific. The land-snails have fewer enemies, and lay fewer eggs. * “Tt was alive 498 days after it was taken from the pond; and in the interim had peen only twice for a few hours in water, to see if it was alive..—Rev. W. O, Newnham, 7 Ann, Nat. Hist. 1850, STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 15 Lastly, the mollusca exhibit the same instinctive care with insects and the higher animals in placing their eggs in situations where they will be safe from injury, or open to the influences of air and heat, or surrounded by the food which the young will require. The tropical bu/im?t cement leaves together to protect and conceal their large bird-like eggs; the slugs bury theirs in the ground; the oceanic-snail attaches them’ to a floating raft; and the argonaut carries them in her frail boat. Fig. 9. Ianthina with its raft. The horny capsules of the whelk are clustered in groups, with spaces pervading the interior for the free passage of sea water ; and the nidamental ribbon of the doris and eolis is attached to a rock or some solid surface from which it will not be detached by the waves. The river-mussel and cyclas carry their parental care still further, and nurse their young in their own mantle, or ina special marsupiwm, designed hke that of the opossum, to protect them until they are strong enough to shift for themselves. If any one imbued with the spirit of Paley or Chateaubriand, should study these phenomena, he might discover more than the ‘‘ barren facts”? which alone appear without significance to the unspiritual eye; he would see at every step fresh proofs of the wisdom and goodness of God, who thus manifests His great- ness by displaying the same care for the maintenance otf His feeblest creatures as for the well-being of man and the stability of the world. STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. Molluscous animals possess a distinct nervous system, instru- ments appropriated to the fiye senses, and muscles by which they execute a variety of movements. They have organs, by which food is procured and digested; a heart, with arteries and yeins, through which their colourless fluids circulate; a 16 MANUAL OF THE MOLLUSCA. breathing-organ; and, in most instances, a protecting shell. They produce eggs, and the young generally pass through one preparatory, or laryal, stage. The nervous system, upon which sensation and the exercise of muscular motion depend, consists of a brain or principal centre, and of various neryes possessing distinct properties: the optic neryes are only sensible of light and colours; the auditory neryes convey impressions of sound; the olfactory, of odours ; the gustatory, of flavours ; whilst the nerves of touch or feeling are widely diffused, and indicate in a more general way the presence of external objects. The neryes by which motion is produced are distinct from these, but so accompany them as to appear like parts of the same cords. Both kinds of nerves cease to act when their connection with the centre is interrupted or destroyed. There is reason to believe that most of the moye- ments of the lower animals result from the reflection of external stimulants (like the process of breathing in man), without the intervention of the will.* In the mollusca, the principal part of the nervous system is a ring surrounding the throat (esophagus), and giving off nerves to different parts of the body. The points from which the nerves radiate are enlargements termed centres (ganglia), those on the sides and upper part of the ring represent the brain, and supply nerves to the eyes, tentacles, and mouth; other centres, connected with the lower side of the oesophageal ring, send neryes to the foot, viscera, and respiratory organ. In the bivalves the branchial centre is the most conspicuous, and is situated on the posterior adductor muscle. In the tunicaries the corresponding nervous centre may be seen between the two orifices in the muscular tunic. This scattered condition of the neryous centres is eminently characteristic of the entire sub- kingdom. Organs of special sense.—Sight. The eyes are two in number, placed on the front or sides of the head; sometimes they are sessile, in others stalked, or placed on long pedicels (ommatophora). The eyes of the cuttle-fishes resemble those of fishes in their large size and complicated structure. Each consists of a strong fibrous globe (sclerotic), transparent in front (cornea), with the opposite internal surface (retina) covered by a dark pigment which receives the rays of light. This chamber is occupied by an aqueous humour, a crystalline lens, and a vitreous humour, as in the human eye. In the strombide, the eye is not less highly organised, but in most of the gasteropoda it has a more * See “Miiller’s Elements of Physiology,” edited by Dr. Baly. STRUCTURE AND PAYSIOLOGY OF THE MOLLUSCA. 1 simple structure, and perhaps only possesses sensibility of light without the power of distinct vision. The larval bivalyes haye also a pair of eyes in the normal position (Fig. 30) near the mouth ; but their development is not continued, and the adults are either eyeless, or possess merely rudimentary organs of vision, in the form of black dots (ocelli) along the margin of the mantle.* These supposed eyes have been detected in a great Fig. 10. Pecten vartus.{ many bivyalyes, but they are most conspicuous in the scallop, which has received the name of argus from Poli on this account (Fig. 10). In the tunicaries similar ocelli are placed between the tentacles which surround the orifices. Sense of Hearing. In the highest cephalopods, this organ consists of two cavities in the rudimentary cranium which pro- tects the brain ; a small calcareous body or otolithe is suspended nyuWaNy Fig. 11. Tentacle of a Nudibranch.} in each, as in the yestibular cavities of fishes. Similar auditory capsules occur near the base of the tentacles in the gasteropoda, and they have been detected, by the vibration of the otolithes, in many bivalves and brachiopods. With the exception of * «Fach possesses a cornea, lens, choroid, and nerve ; they are, without doubt, organs of vision.” (Garner.) The same conclusion is arrived at by Duvernoy ina paper in the Annales des Sciences Naturelles for 1852. ¢ Pecten varius, L., from a specimen dredged by Mr. Bowerbank, off Tenby m, the pallial curtains; dr, the branchie. ¢ Fig. 11, Tentacle of Eolis coronata, Forbes, from Alder and Hancock. 18 MANUAL OF THE MOLLUSCA. tritonia and eolis, none of the mollusca haye been observed to emit sounds. (Grant.) Sense of Smell. This faculty is evidently possessed by the cuttle-fishes and gasteropods; snails discriminate their food by it, slugs are attracted by offensive odours, and many of the marine zoophaga may be taken with animal baits. In the pearly nautilus there is a hollow plicated process beneath each eye, which M. Valenciennes regards as the organ of smell.* Messrs. Hancock and Embleton attribute the same function to the lamellated tentacles of the nudibranchs, and compare them with the olfactory organs of fishes. The labial tentacles of the bivalves are considered to be organs for discriminating food, but in what way is unknown (Fig. 18, 7, t). The sense of taste is also indicated rather by the habits of the animals and their choice of food than by the structure of a special organ. The acephala appear to exercise little discrimination in selecting food, and swallow anything that is small enough to enter their mouths, including lying animalcules, and eyen the sharp spicula of sponges. In some instances, however, the oral orifice is well guarded, as in pecten (Fig. 10). In the Encephala the tongue is armed with spines, employed in the comminution of the food, and cannot possess a yery delicate sense. The more ordinary and diffused sense of touch 1s possessed by all the mollusca ; it is exercised by the skin, which is everywhere soft and lubricous, and in a higher degree by the fringes of the bi- valves (Fig. 12), and by the fila- ments and tentacles (vibracula) of the gasteropods; the eye- pedicels of the snail are evidently endowed with great sensitiveness in this respect. That shell-fish are not very sensible of pain, we may well believe, on account of their tenacity of life, and the extent to which they haye the power of reproducing lost parts. Muscular System. The muscles of the mollusca are principally connected with the skin, which is exceedingly contractile in every part. The snail affords a remarkable, though familiar instance, when it draws in its ecye-stalks by a process like the Fig. 12. Lepton squamosum.t * Mr. Owen regards the membranous lamelie between the oral tentacles and in front of the mouth, as the seat of the olfactory sense. See Fig. 51 t Fig. 12, Lepton squamosum, Mont., from a drawing by Mr. Alder, in the British Moilusca ; copied by permission of Mr. Van Voorst, STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 19 inversion of a gloye-finger; the branching gills of some of the sea-slugs, and the tentacles of the cuttle-fishes are also eminently contractile.* The inner tunic of the ascidians (Fig. 8, t) presents a beautiful example of muscular tissue, the crossing fibres haying much the appearance of basket-work; in the transparent salpians, these fibres are grouped in flat bands, and arranged in charac- teristic patterns. In this class (twnicata) they act only as sphincters (or circular muscles), and by their sudden contraction expel the water from the branchial cavity. The muscular foot of the bivalves is extremely flexible, having layers of circular fibres for its protrusion (Fig. 18, /), and longitudinal bands for its retraction (Fig. 30 *); its structure and mobility has been compared to that of the human tongue. In the burrowing shell-fish (such as solen), it is very large and powerful, and in the boring species, its surface is studded with siliceous particles (spicula), which renders it a very efficient instru- ment for the enlargement of their cells. (Hancock). In the attached bivalves it is not developed, or exists only inarudi- = Fig. 15. Dreissena.t mentary state, and is subsidiary to a gland which secretes the material of those threads with which the mussel and pinna attach themselves (Fig. 13). These threads are termed the byssus ; the plug of the anomia and the pedicel of terebratula are modifications of the byssus. In the cuttle-fishes alone we find muscles attached to internal cartilages which represent the bones of vertebrate animals; the muscles of the arms are inserted in a cranial cartilage, and those of the fins in the lateral cartilages. Muscles of a third kind are attached to the shell. The valves of the oyster (and other mono-myaries) are connected by a single muscle; those of the cytherea (and other di-myaries), by two; the contraction of which brings the valves together. They are hence named adductors; and the part of the shell * The muscular fibres of molluscs frequently present the transverse stripes which characterise voluntary muscles in the higher animals. Striped muscular fibre has been observed in Salpa (Huxley); and in Waidheimia australis by Hancock ; a strict search Wus made by that able anatomist for the purpose of discovering such fibre amongst the hingeless brachiopods, but without success. Striped fibres have been scen in the gasteropods. 4 Fig. 13. Drewssena polymorpha (Pallas sp.), from the Surrey timber-docks f, foot ; b, byssus, 20 MANUAL OF THE MOLLUSCA. to which they are attached is always indicated by scars (Fig. 14, a, a’). The border of the mantle is also muscular,.and the place of its attachment is marked in the shell by a line called the palliat impression (p); the presence of a bay, or sinus (s), in this line, shows that the animal had retractile siphons; the foot of the animal is withdrawn by retractor muscles also attached to the Fig. 14. Left valve of Cytherea chionc.* shell, and leaying small scars near those of the adductors (Fig 30*). The gasteropods withdraw into their shells when alarmed, by a shell-muscle, which passes into the foot, or is attached to the operculum ; its impression is horse-shoe-shaped in the limpet, as also in navicella, concholepas, and the nautilus; it becomes deeper with age. In the spiral univalves, the scar is less con- spicuous, being situated on the colwmella, and sometimes diyided, — forming two spots. It corresponds to the posterior retractors in the bivalves. Digestive System. This part of the animal economy is all- important in the radiate classes, and scarcely of less consequence in the mollusca. In those bivalves, which have a large foot, the digestive organs are concealed in the upper part of that organ ; the mouth is unarmed, except by two pairsof soft membranous | * Fig.14. Cytherea chione, L., coast of Devon (original); A, the hinge ligament; u, the umbo; Z, the lunule; c, cardinal tooth; ¢ ¢’, lateral teeth; a, anterior adductor ; a', posterior adductor; p, pallial impression; s, sinus, occupied by retractor of the siphens. STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 21 palpi, which look like accessory gills (Fig. 18, 7, t), The ciliated arms of the brachiopods occupy a similar position (Figs. 4, 5, 6). The encephalous mollusca are frequently armed with horny jaws, working vertically like the mandibles of a bird ; in the land-snails, the upper jaw is opposed only by the denticulated tongue, whilst the limneids have two additional horny jaws, acting laterally. The tongue is muscular and armed with recurved spines (or lingual teeth), arranged in a great variety of patterns, which are eminently characteristic of the genera.* Their teeth are amber-coloured, glossy, and translucent ; and being siliceous (they are insoluble in acid), they can be used like a file for the abrasion of very hard sub- stances. With them the limpet rasps the stony nullipore, the whelk bores holes in other shells, and the cuttle-fish doubtless uses its tongue in the same manner as the cat. The tongue, or lingual ribbon, usually forms a triple band, of which the central part is called the rachis, and the lateral tracts pleurce, the rachidian teeth sometimes form a single series, overlapping Fig. 15. Lingual Teeth of Mollusca. each other, or there are lateral teeth on each side of a median series. The teeth on the pleurw are termed wncini; they are extremely numerous in the plant-eating gasteropods (Fig. 15, A).t Sometimes the tongue forms a short semicircular ridge, con- * The preparation of the lingual ribbon as a permanent microscopic object, requires some nicety of manipulation, but the arrangement of the teeth may be seen by merely compressing part of the animal between two pieces of glass. { Fig. 15. A, lingual teeth of trochus cinerarius (after Lovén). Only the median tooth, and the (5) lateral teeth, and (90) unczni of one side of a single row are repre- sented. B, one row of the lingual teeth of cyprea europaa; consisting of a median tooth and three wncini on each side of it. dads MANUAL OF THE MOLLUSCA, tained between the jaws; at others, it is extremely elongated, and its folds extend backwards to the stomach. The lingual ribbon of the limpet is longer than the whole animal; the tongue of the whelk has 100 rows of teeth; and the great slug has 160 rows, with 180 teeth in each row. The front of the tongue is frequently curved, or bent quite over; it is the part of the instrument in use, and its teeth are often broken or blunted. The posterior part of the lingual 2G E¢ << a ee ee ee EH Sa bar Ss = Fig. 16. Tongue of the Whelk.* ribbon usually has its margins rolled together and united, form- ing a tube, which is presumed to open gradually. The new teeth are developed from behind forwards, and are brought successively into use, as in the sharks and rays amongst fishes. In the bullide the rachis of the tongue is unarmed, and the business of comminuting the food is transferred to an organ which resembles the gizzard of a fowl, and is often paved with calcareous plates, so large and strong as to crush the small shell-fish which are swallowed entire. In the aplysia, which is ayegetable-feeder, the gizzard is armed with numerous small plates and spines. ‘The stomach of some bivalves contains an instrument called the ‘‘ crystalline stylet,”’ which is con- jectured to haye a similar use. In the cephalopods there is a crop in which the food may accumulate, as well as a gizzard for its trituration. The liver is always large in the mollusca (Fig. 10) ; its secre- tion is derived from arterial blood, and is poured either into the stomach or the commencement of the intestine. In the nudi- Fig.17. Gizzard of Bulla. ¢ * Fie, 16. Lingual ribbon of buccomum undatum (original), from a preparation communicated by W. Thomson, Esq., of King’s College. a, anterior; p, posterior; /, lateral; 7, rachidian. + Fig. 17. Gizzard of bulla lignaria (original). Front and side view of a half- growr specimen, with the part nearest the head of the animal downwards; in the front view the plates are in contact. The cardiac orifice is in the centre, in front; te pyloric orifice is on the posterior dorsal side, near the small transverse plate. STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. ao branchs, whose stomachs are often remarkably branched, tho liver accompanies all the gastric ramifications, and even enters the respiratory papillze on the backs of the eolids. The exist- ence of a renal organ has been ascertained in most classes; in the bivalves it was detected by the presence of uric acid. The intestine is more convoluted in the herbivorous than in the carnivorous tribes: in the bivalves and in haliotis it passes through the yentricle of the heart; its termination is always near the respiratory aperture (or the excarrent orifice, where there are two*), and the excrements are carried away by the water which has already passed over the gills. Besides the organs already mentioned, the encephalous molluses are always furnished with well-developed salivary glands, and some have a rudimentary pancreas ; many haye also special glands for the secretion of coloured fluids, such as the purple of the murex, the violet liquid of ianthina and aplysia, the yellow of the bullide, the milky fluid of eolis and the inky secretion of the cuttle-fishes. The gland that secretes this fluid is situated on the mantle. It consists of a thin layer of elongated cells, and is to be found in most gasteropods. The fluid produced appears to have different properties in different species. Thus in aplysia and some snails it possesses colour at the moment of being secreted; but in others it is colourless, as, for instance, in turbo littoralis and trochus cinerarius. Inmurex and purpura also it is colourless when secreted; but on being exposed to the sun it becomes first yellowish and ultimately violet, after having passed through various intermediate tints -formed by the mixture of yellow, blue, and red. According to M. Lacaze Duthiers it is probable that the Romans obtained their purple dye from three or four species of mollusc, such as murex trunculus, and brandaris, and purpura hemastoma. A few molluscs exhale peculiar odours, like the garlic-snail (helix alliaria) and eledone moschata. Many are phosphorescent, espe- cially the floating tunicaries (salpa and pyrosoma), and bivalves which inhabit holes (pholadide). Some of the cuttle-fishes are shghtly luminous; and one land-slug, the phosphoraz, takes its name from the same property. Circulating system. The mollusca have no distinct absorbent system, but the product of digestion (chyle) passes into the general abdominal cavity, and thence into the larger veins ; * In most of the gasteropods the intestine returns upon iself, and terminates on the _ right side, near the head. Occasionally it ends in a perforation more or less removed from the margin of the aperture, as in trochotoma, fissurella, macrochisma, and dentalium. Tn chiton the intestine is straight, and terminates posteriorly. 24 MANUAL OF THE MOLLUSCA. which are perforated with numerous round apertures. The circulating organs are the heart, arteries, and veins; the blood is colourless, or pale bluish white. The heart consists of an auricle (sometimes divided into two), which receives the blood from the gills; and a muscular ventricle which propels it into the arteries of the body. From the capillary extremities of the arteries it collects again into the yeins, circulates a second time through the respiratory organ, and returns to the heart as arterial blood. Besides this systemic heart, the circulation is aided by two additional branchial hearts in the cuttle-fishes. Mr. Alder has counted from 60 to 80 pulsations per minute in the nudibranchs, and 120 per minute in a vitrina. Both the arteries and veins form occasionally wide spaces, or sinuses ; in the cuttle-fishes the cesophagus is partly or entirely surrounded by a venous sinus ; and in the acephala the visceral cavity itself forms part of the circulating system. Aquiferous system. Recent anatomical researches by Messrs. Hancock, Rolleston, Robertson, Williams, and others have thrown considerable doubt upon the existence of any aquiferous system in the mollusca. There are certainly a number of pores which open to the external water; these are situated either in the centre of the creeping disc, as in cypreea, conus, and ancil- laria; or at its margin, as in haliotis, doris, and aplysia. In the cuttle-fishes they are variously placed, on the sides of the head, or at the bases of the arms; some of them conduct to the large sub-orbital pouches, into which the tentacles are retracted. According to Messrs. Rolleston and Robertson* there is no con- nection between the blood vascular and the aquiferous systems; and the foot in the lamellibranchiates is distended by means of the aquiferous canals, which they regard as a rudimentary kidney. Agassiz and Lacaze Duthiers, on the other hand, assert that there is a connection between the two systems. The proof relied on by the former observers was that when a coloured injection was forced in through a vein, and an injection of a different colour was sent into the aquiferous canals, two coloured systems of ramification were formed, which the microscope showed to be distinct up to the furthest extremities. Agassiz also used a coloured injection ; he states that when it was injected through the large pore in the pedal surface of some species of pyrula, uot only was the system of canals in the foot filled, but also the whole of the circulatory system. He also states that when a mactra is taken out of the water it discharges a quantity of fluid from the foot, which consists of salt water, in which floats * Philosophical Transactions, 1862, STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 25 a iarge number of blood corpuscles. This he regards as a proof of the mixture of blood and sea water within the body of the animal. Respiratory system. The respiratory process consists in tke exposure of the blood to the influence of air, or water contain- ing air; during which oxygen is absorbed and carbonic acid liberated. It is a process essential to animal life, and is never entirely suspended, even during hybernation. Those air- breathers that inhabit water are obliged to visit the surface frequently; and stale water is so inimical to the water-breathers, that they soon attempt to escape from the confinement of a glass or basin, unless the water is frequently renewed. In general, fresh water is immediately fatal to marine species, and salt water to those which properly inhabit fresh ; but there are some which affect brackish water, and many which endure it to a limited extent. The depth at which shell-fish live is probably influenced by the quantity of oxygen which they require; the most active and energetic races liye only in shallow water, or near the surface ; those found in very deep water are the lowest in their instincts, and are specially organised for their situation. Some water- breathers require only moist sea air, and a bi-diurnal visit from the tide—like the peri- winkle, limpet, and kellia; whilst many air - breathers liye entirely in the water or in damp places by the water- side. In fact, the nature of the repiratory process is the same, whether it be aquatic or aérial, and it is essential in each case that the surface of the breathing-organ should be preserved moist. The process is more complete in proportion to the extent and minute sub- division of the vessels, in which the circulating fluid is exposed to the revivifying influence. The land-snails (pulmonéfera) haye a lung or air-chamber, formed by the folding of the mantle, over the interior of which the pulmonary vessels are distributed; this chamber has a iil ibpril Ti Fig. 18. Zrigona pectinata.* * Trigonia pectinata, Lam.-(original). Brought from Australia by the late Captain Owen Stanley. The gills are seen in the centre through the transparent mantle. 9, mouth; 7 ¢, labial tentacles ; 7, foot; v, vent. sa Ge 26 MANUAL OF THE MOLLUSOA. round orifice, on the right side of the animal, which opens and closes at irregular intervals. ‘The air in this cavity seems to renow itself a suffictent rapidity (by the law of diffusion), without any special mechanism. In the aquatic shell-fish respiration is performed by the mantle, or by a portion of it specialised, and forming a gill (branchia). It is affected by the arms in all the brachiopoda, while the mantle serves as an auxiliary. In the ordinary bivalves the gills form two membranous plates on each side of the body; the muscular mantle is still sometimes united, form - ing a chamber with two orifices, into one of which the water flows, whilst it escapes from the other; there is a third opening in front for the foot, but this in no wise influences the branchial circulation. Sometimes the orifices are drawn out into long tubes or siphons, especially in those shell-fish which burrow in sand (Figs. 19 and 7). Fig. 19. Bivalve with long siphons.* Those bivalyes which have no siphons, and even those in which the mantle is divided into two lobes, are provided with valves or folds which render the respiratory channels just as complete in effect. These currents are not in any way connected with the opening and closing of the valves, which is only done in moving, or in efforts to expel irritating particles.t In some of the gasteropoda the respiratory organs form tufts, exposed on the back and sides (as in the nudibranchs), or pro- tected by a fold of the mantle (as in the inferobranchs and tectibranchs of Cuyier).{ But in most the mantle is inflected, * Fig. 19. Psammobia vespertina, Chemn. after Poli, reduced one-half. The arrows indicate the direction of the current; 7 s, respiratory siphon ; es, excurrent siphon; J, foot. } If ariver-mussel 68 placed in a glass of water, and fine sand let fall gently over its respiratory orifices, the particles will be seen to rebound from the vicinity of the upper aperture, whilst they enter the lower one rapidly. But as this kind of food is not palatable, the creature will soon give a plunge with its foot, and closing its valves, spirt the water (and with it the sand) from both orifices; the motion of the foot is, of course, intended to change its position. ¢ Mr. Collingwood (Annals of Nat. Hist. for 1861), in discussing what function these tufts or papillee perform, concludes that morphologically and physiologically they are not branchie, en STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA, 27 and forms a yaulted chamber over the back of the neck, in which are contained the pectinated or plume-lke gills (Fig. 68). In the carnivorous gasteropods (siphonostomata) the water passes into this chamber through a siphon, formed by a pro- longation of the upper margin of the mantle, and protected by the canal of the shell; after traversing the length of the gill, it returns and escapes through a posterior siphon, generally less developed, but very long in ovulum volva, and forming a tubular spine in typhis. In the plant-eating sea-snails (holostomata) there is no true siphon, but one of the ‘‘ neck-lappets”’ is sometimes curled up and performs the same office, as in paludina and ampullaria (Fig. 109). The in-coming and out-going currents in the branchial chamber are kept apart by a valye-lke fringe, con- tinued from the neck-lappet. The out-current is still more effectually isolated in fisswrella, haliotis, and dentaliwm, where it escapes by a hole in the shell, far removed from the point at which it entered. Near this outlet are the anal, renal, and generative orifices. The cephalopods have two or four plume-like gills, sym- metrically placed in a branchial chamber, situated on the under- side of the body; the opening is in frent, and occupied by a funnel, which, in the nautilus, closely resembles the siphon of the paludina, but has its edges united in the cuttle-fishes. The free edge of the mantle is so adapted that it allows the water to enter the branchial chamber on each side of the funnel: its muscular walls then contract and force the water through the funnel, an arrangement chiefly subservient to locomotion.* Mr. Bowerbank has observed that the eledone makes twenty respirations per minute when resting quietly in a basin of water. In most instances, the water on the surface of the gills is changed by ciliary action alone; in the cephalopods and salpians it is renewed by the alternate expansion and contraction of the respiratory chamber, as in the vertebrate animals. The respiratory system is of the highest importance in the economy of the mollusca, and its modifications afford most valuable characters in classification. It will be observed that the Cuyierian classes are based on a variety of particulars, and are very unequal in importance; but the orders are characterised by their respiratory conditions, and are of much more nearly equal value. * A very efficient means of locomotion in the slender pointed calamaries, which dart backwards with the recoil, like rockets. c2 95 MANUAL OF THE MOLLUSCA. ORDERS, CLASSES. Dibranchiata. Owen. Tetrabranchiata. Owen. CEPHALOPODA, Nucleobranchiata. Bl. ANCE PEATIA. enie Gove so Prosobranchiata. M. Edw. Pulmonifera. Cuv. GASTEROPODA. Opisthobranchiata. M, Edw. | Aporobranchiata. BI. PTEROPODA. Palliobranchiata. Bl. BRACHIOPODA, WGHPHATLA . . ... s « ~ Lamellibranchiata. (BI CONCHIFERA, Heterobranchiata. BL TUNICATA, The Shell. The relation of the shell to the breathing-organ is very intimate: indeed, it may be regarded as a pneumo-skeleton, being essentially a calcified portion of the mantle, of which the breathing-organ is at most a specialised part.* The shell is so characteristic of the mollusca that they have been commonly called ‘‘ testacea”’ (from testa, ‘‘a shell”) in scientific books; and the popular name of ‘“‘ shell-fish,” though not quite accurate, cannot be replaced by any other epithet in common use. In one whole class, however, and in seyeral families, there is nothing that would be popularly recognised as a shell. Shells are said to be external when the animal is contained in them, and internal when they are concealed in the mantle; the latter, as well as the shell-less species, being called naked molluscs. Three-fourths of the mollusca are wnivalve, or have but one shell; the others are mostly bivalve, or haye two shells; the pholads have accessory plates, and the shell of chiton consists of eight pieces. Most of the multivalves of old authors were articnlate animals (cirripedes), erroneously included with the mollusca, which they resemble only in outward appearance. All, except the argonaut, acquire a rudimental shell beforu they are hatched, which becomes the nucleus of the adult shell ; it is often differently shaped and coloured from the rest of the shell, and hence the fry are apt to be mistaken for distinct species from their parents. In cymba (Fig. 20) the nucleus is large and irregular; in * In its most reduced form the shell is only a hollow cone, or plate, protecting the breathing organ and heart, as in limar, testacella, carinaria. Its peculiar features always relate to the condition of the breathing-organ; and in terebratula and pelonaia it becomes identified with the gill. In the nudibranchs the vascular mantle performs wholly or in part the respiratory office. In the cephalopods the shell becomes complicated by the addition of a distinct, internal, chambered portion ( phragmocone), whioh is properly a visceral skeleton ; in spirula the shell is reduced to this part, ° oe a ae Oe STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 29 fusus antiquus it is cylindrical; in the pyramidellide it is oblique ; and it is spiral in carinaria, atlanta, and many limpets, which are symmetrical when adult. The rudimentary shell of the nudibranchs is shed at an early age, and neyerreplaced. In this respect the molluscan shell differs entirely from the shell of the crab and other articulate animals, which is periodically cast off and renewed. In the bivalves the embryonic shell forms the umbo of each valve; it is often very un- like the after-growth, as in unio pictorum, cyclas henslowiana, and pecten pusio. In || attached shells, like the oyster and anomia, ||! :: the umbo frequently presents an exact imita- tion of the surface to which the young shell orignally adhered. Shells are composed of carbonate of lime, with a small proportion of animal matter. The source of this lime is to be looked for in their food. Modern inquiries into organic chemistry haye shown that vegetables derive their elements from the mineral kmgdom _ : (air, water, and the soil), and animals theirs *’* oy ee: from the yegetable. The sea-weed filters the salt water, and separates lime as well as organic elements; and lime is one of the most abundant mineral matters in land plants. From this source the mollusca obtain lime in abundance, and, indeed, we find frequent instances of shells becoming unnaturally thickened through the superabundance of this earth in their systems. On the other hand, instances occur of thin and delicate-shelled varieties in still, deep water, or on clay bottoms; whilst in those districts which are wholly destitute of lime, like the Lizard in Cornwall, and similar tracts of magnesian- silicate in Asia Minor, there are no mollusca.—(Lorbes.) The texture of shells is various and characteristic. Some, when broken, present a dull lustre ike marble or china, and are termed porcellanous ; others are pearly or nacreous ; some haye a fibrous structure ; some are horny, and others glassy and translucent. The nacreous shells are formed by alternate layers of very thin membrane and carbonate of lime, but this alone does not * Fig. 20. Cymba proboscidalis, Lam., from a very young specimen in the cabinet of Hugh Cuming, Esq., from Westeru Afiica. 380 MANUAL OF THE MOLLUSCA,. give the pearly iustre, which appears to depend on minute undulations of the layers, represented in Fig. 23. This lustre has been successfully imitated on engraved steel buttons. Nacreous shells, when polished, form ‘‘mother of pearl;” when digested in weak acid they leave a membraneous residue which retains the original form of the shell. This is the most easily destructible of shell-textures, and in some geological formations we find only casts of the nacreous shells, whilst those of fibrous texture are completely preserved. Pearls are produced by many bivalves, especially by the Oriental pearl-mussel (avicula margaritifera), and one of the British river mussels (unio margaritiferus). They are also found occasionally in the common oyster, in anodonta cygnea, pinna nobilis, mytilus edulis, or common mussel, and in spondylus gederopus. In these they are generally of a green or rose colour. The pearls found in arca noe are violet, and in anomia cepa purple. ‘They are similar in structure to the shell, and, like it, consist of three layers ; but what is the innermost layer in the shell is placed on the outside in the pearl. The iridescence is due to light falling upon the out-cropping edges of partially transparent corrugated plates. The thinner and more trans- parent the plates the more beautiful is the iridescent lustre; and this is said to be the reason why sea pearls excel those obtained from fresh-water molluscs. Besides the furrows formed by the corrugated surface there are a number of fine dark lines (+55 inch apart), which may add to the lustrous effect. In some pearls these lines run from pole to pole like the longitudes on the globe; in others they run in various directions; and in a few the lines on the same pearl have different directions, so that they cross each other. The nucleus frequently consists of a fragment of a brownish-yellow organic substance, which behaves in the same way as epidermis when treated with certain chemical re-agents. Sand is generally said to be the nucleus; but this is simply a conjecture which has gradually become regarded as a fact; it is quite the exception for sand to be the nucleus; as a general rule it is some organic substance. In some districts one kind of nucleus seems to be more common than another; at least, this is how the different results obtained by observers in different localities may be explained. Filippi (Swill origine delle Perle. Translated in Miller’s Archiv. 1856) found distoma to be the nucleus in many cases; Kuchenmeister found that the pearls were most abundant in the molluscs living in the still parts of the river Elster, where the water-mites (limnochares anodonte) existed most nume- STRUCIURE AND PHYSIOLOGY OF THE MOLLUSCA, ol rously. The most generally prevalent nucleus appears to be the bodies or eggs of minute internal parasites, such as /i/aria, distoma, buchephalus, &c.* Completely spherical pearls can only be formed loose in the muscles, or other soft parts of the animal. The Chinese obtain them artificially by introducing into the living mussel foreign substances, such as pieces of mother-of-pearl fixed to wires, which thus become coated with a more brilliant material. NEN RNIN . SNOW NY . \ Nes \ YAD DAT Fig. 21. Pinna. Fig. 22. Terebratula. Fig. 23. Pearl.t Similar prominences and concretions—pearls which are not pearly—are formed inside porcellanous shells; these are as variable in colour as the surfaces on which they are formed.t The jibrous shells consist of successive layers of prismatic cells containing translucent carbonate of lime; and the cells of each successive layer correspond, so that the shell, especially when yery thick (as in the fossil énoceramus and trichites), will break up vertically into fragments, exhibiting on their edges a structure lke arragonite, or satin-spar. Horizontal sections exhibit a cellular network, with here and there a dark cell, which is empty (Fig. 21). The oyster has a laminated structure, owing to the irregular accumulation of the cells in its successive layers, and breaks up into horizontal plates. In the boring-shells (pholadide) the carbonate of lime has an atomic arrangement like arragonite, which is considerably harder than calcareous spar; in other cases the difference in hardness depends on the proportion of animal matter and the manner in which the layers are aggregated.§ * Drs. Mobius and Kelaart, Annals of Nat. Hist., i., 1858, p. 81. { Figs. 21, 22, 23. Magnified sections of shells, from Dr. Carpenter. Fragments of shell ground very thin, and cemented to glass slides with Canada balsam, are easily prepared, and form curious microscopic objects. ft They are pink in turbinellus and strombus; white in cstrea; white or glassy, purple or black, in mytilus ; rose-coloured and translucent in punna.—( Gray.) § The specific gravity of floating shells (such as argonauta and ianthina) is lower than that of any others.—(De la Beche.) 32 MANUAL OF THE MOLLUSCA. In many bivalve shells there occurs a minute tubular struc- ture, Which is yery conspicuous in some sections of pinna and oyster-shell. This tubular structure is frequently occasioned by the growth of a confervyoid sponge, hence great care is required in determining whether the perforations are an essential part of the shell. The brachiopoda exhibit a characteristic structure by which the smallest fragment of their shells may be determined ; it consists of elongated and curved cells matted together, and often perforated by circular holes, arranged in quincunx order (Fig. 22). But the most complex shell-structure is presented by the porcellanous gasteropoda. These consist of three strata which readily separate in fossil shells, on account of the remoyal of their animal cement. In Fig. 24, a represents the outer, b the middle, and c the inner stratum; they may be seen also in Fig. 25. Hach of © these three strata 1s com- posed of very numerous yer- tical plates, ike cards placed on edge; and the direction of the plates is sometimes transverse in the central stratum, and lengthwise in the outer and inner (as in cyprea, cassis, ampullaria, and bulimus), or longitudinal in the middle layer and transverse in the others (e. g. conus, pyrula, oliva, and voluta). Each plate, too, is composed of a series of prismatic cells, arranged obliquely (45°), and their direction being changed in the successive plates, they cross each other at right angles. Tertiary fossils best exhibit this structure, either at their broken edge, or in polished sections.—(Bowerbank.)t The argonaut-shell and the bone of the cuttle-fish have a peculiar structure; and the Hippurite is distinguished by a Fig. 24. Sections of a Cone.* * Sections of Conus ponderosus, Brug., from the Miocene of the Touraine. A, longitudinal section of a fragment; B, complete horizontal section; a, outer layer; J, middle ; c, inner layer; d, e, f, lines of growth. 7 It is necessary to bear in mind that fossil shells are often pseudomorphous, or mere easts, in spar or chalcedony, of cavities once occupied by shells; such are the fossils found at Blackdown, and many of the London clay fessils at Barton. . The Paleozoic fossils are often metamorphic, or have undergone a re-arrangement of their particles, like the rocks in which they occur. STRUCIURE AND PHYSIOLOGY OF THE MOLLUSCA. 30 cancellated texture, unlike any other shell, except yerhaps some of the cardiacece and chamacee. Epidermis. All shells have an outer coat of animal matter called the ‘‘epidermis”’ (or periostracum), sometimes thin and transparent, at others thick and opaque. It is thick and olive- coloured in all fresh-water shells and in many arctic sea-shells (e. g. cyprina and astarte); the colours of the land-shells often depend on it ; sometimes it is silky as in helix sericea, or fringed with hairs as in trichotropis ; in the whelk and some species of triton and conus it is thick and rough, like coarse cloth, and in some modiolas it is drawn out into long beard-like filaments. In the cowry and other molluscs with large mantle lobes the epidermis is more or less covered up by an additional layer of shell deposited externally. The epidermis has life, but not sensation, ike the human scarf-skin ; and it protects the shell against the influence of the weather and chemical agents ; it soon fades or is destroyed after the death of the animal in situations where, whilst living, it would have undergone no change. In the bivalves it is organically connected with the margin of the mantle. It is most developed in shells which frequent damp situations, amongst decaying leayes, and in fresh-water shells. All fresh waters are more or less saturated with carbonic-acid gas, and in limestone countries hold so much lime in solution as to deposit it in the form of tuwfa on the mussels and other shells.* But in the absence of lime to neutralise the acid the water acts on the shells, and would dissolve them entirely if it were not for their protecting epidermis. As it is, we can often recognise fresh-water shells by the erosion of those parts where the epidermis was thinnest, namely, the points of the spiral shells and the wmbones of the bivalves, those being also the parts longest exposed. Specimens of melanopsis and bithynia become truncated again and again in the course of their growth, until the adults are sometimes only half the length they should be, and the discoidal planorbis sometimes becomes perforated by the remoyal of its inner whorls; in these cases the animal closes the break in its shell with new layers. Some of the unios thicken their umbones enormously, and form a layer of enimal matter with each new layer of shell, so that the river action is arrested at a succession of steps. * As at Tisbury, in Wiltshire, where remarkable specimens of anodons were obtained by the late Miss Benett. C3 34 MANUAL OF THE MOLLUSCA. FORMATION AND GROWTH OF THE SHELL. The shell, as before stated, is formed by the mantle ; indeed, each layer of it was once a portion of the mantle, either in the form of a simple membrane or as a layer of cells; and each layer was successively calcified (or hardened with carbonate of lime) and thrown off by the mantle to unite with those pre- viously formed. Being extravascular it has no inherent power of repair.—( Carpenter.) The epidermis and cellular structures are formed by the margin (or collar) of the mantle; the membranous and nacreous layers, by the thin and transparent portion which contains tho viscera; hence we find the pearly texture only as a lining inside the shell, as in the nautilus, and all the aviculide and turbinide. If the margin of a shell is fractured during the lifetime of the animal, the injury will be completely repaired by the re- production both of the epidermis and of the outer layer of shell with its proper colour. But if the apex is destroyed, or a hole made at a distance from the aperture, it will merely be closed with the material secreted by the visceral mantle. Such inroads are often made by boring worms and shell, and even by a sponge (cliona), which completely mines the most solid shells. In Dr. Gray’s cabinet is the section of a cone, in whose apex a colony SSS 2 Sau = Fig. 25. Section of a T= perforated by Lithodomi, of lithodomi had settled, compelling the animal to contract itself faster than it could form shell to fill up the void. Lines of growth. So long as the animal continues growing each new layer of shell extends beyond the one formed before it; and, in consequence, the external surface becomes marked with lines of growth. During winter, or the season of rest STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 35 which corresponds to it, shells cease to grow ; and these periodic resting-places are often indicated by interruptions of the other- wise regular lines of growth and colour, or by still more obyious signs. It is probable that this pause, or cessation from growth, extends into the breeding season; otherwise there would be two periods of growth and two of rest in each year. In many shells the growth is uniform; but in others each stage is finished by the development of a fringe, or ridge (varia), or of a row of spines, as in tridacna and murex.—( Owen, Grant.) Adult characters. The attainment of the full growth proper to each species is usually marked | : by changes in the shell. Some bivalyes, like the oyster and gryphea (Fig. 26), continue to increase in thickness long after they have ceased to grow out- wards; the greatest addition is made to the lower yalye, espe- cially near the umbo; and in the ; zs spondylus some parts ofthe mantle ‘Fis: 76 Section of gryphea.* secrete more than others, so that cayities, filled with fluid, are left in the substance of the shell. The adult teredo and jfistulana close the end of their burrows ; the pholadidea fills up the great pedal opening of its valves; and the aspergillum forms the porous disc from which it takes its name. Sculptured shells, particularly ammonites, and species of rostel- laria and fusus, often become plain in the last part of their growth. But the most charac- teristic change is the thickening and contrac- tion of the aperture in the univalyes. The young cowry (Fig. 27) has a thin, sharp lip, which becomes curled inwards, and enormously thickened and toothed in the adult; the ptero- ceras (Pl. 4, fig. 3) develops its scorpion-like claws only when full-grown; and the land- snails form a thickened lip, or narrow their aperture with projecting processes, so that it rig. 27. Young is a marvel how they pass in and out, and how Cowry.} they can exclude their eggs (e.g. Pl. 12, fig. 4, anastoma; and Fig. 5, helia hirsuta). * Fig. 26. Sectian of gryphea meurva, Sby. Lias, Dorset (original; diminished one-half) ; the upper valve is not much thickened; the interior is filled with lias, | Cyprea testudinaria, L., young. 56 MANUAL OF THE MOLLUSCA. Yet at this time they would seem to require more space and accommodation in their houses than before, and there are several curious ways in which this is obtained. The neritide and auriculide dissolve all the internal spiral column * of their shells; the cone (Fig. 24, B) removes all but a paper-like portion of its inner whorls; the cowry goes still further, and continues remoying the internal layers of its shell-wall, and depositing new layers externally with its overlapping mantle (Fig. 93), until, in some cases, all resemblance to the young shell is lost in the adult. The power which molluses possess of dissolving portions of their own shells is also exhibited by the murices in remoying those spines from their whorls which interfere with their growth; and by the purpure and others in wearing away the wall of their aperture. The agency in these cases is supposed to be chemical. Some support is given to this view by the composi- tion of the saliva of doliwm galea (closely allied to the purpure), which has been examined by Professor Troschel. A chemical analysis showed that it contained a minute proportion only of organic matter, and consisted of 94 per cent. of water, the remainder being almost entirely muriatic and sulphuric acids, and the sulphates of magnesia, potash, and soda. The secretion is apparently not used to assist digestion, since minute cal- careous shells were found in the stomach uninjured. It is not used for perforating stones; and what its function is remains uncertain. We mention these facts here to show that dilute acids are secreted, which in some cases may be used for dis- solying away the shell. The saliva, however, has no effect on the inside of the shell of the doliwm; indeed, it is said to be unalterable by strong acids. (Monatsberichte der Academie in Berlin, 1854, p. 486). Decollated shells. It frequently happens that as spiral shells become adult they cease to occupy the upper part of their cavity; the space thus vacated is sometimes filled with solid shell, asin magilus; or it is partitioned off, as in vermetus, euomphalus, turritella, and triton (Fig. 62). The deserted apex is sometimes yery thin, and becoming dead and brittle, it breaks away, leaving the shell truncated or decollated. This happens constantly with the truncatelle, cylindrelle, and bulimus decollatus ; amongst the fresh-water shells it depends upon local circumstances, but is yery common with pirena and cerithidea. Forms of shells. These will be described particularly under * This is sometimes done by the hermit-crab to thie shell it occupies, STRUCTURE AND PHYSIOLOGY OF THI MOLLUSCA. 37 each class ; enough has been said to show that in the molluscan shell (as in the vertebrate skeleton) indications are afforded of many of the leading affinities and structural peculiarities of the animal. It may sometimes be difficult to determine the genus of a shell, especially when its form is very simple; but this results more from the imperfection of our technicalities and systems than from any want of co-ordination in the animal and its shell. Monstrosities. The whorls of spiral shells are sometimes separated by the interference of foreign substances, which adhere to them when young; the garden-snail has been found in this condition, and less complete instances are common amongst sea-shells. Discoidal shells occasionally become spiral (as in specimens of planorbis found at Rochdale), or irregular in their growth, owing to an unhealthy condition. The discoidal ammonites sometimes show a slight tendency to become spiral, and more rarely become unsymmetrical, and have the keel on one side instead of in the middle. All attached shells are liable to interference in their growth, and malformations consequent on their situation in cayities, or from coming in contact with rocks. The dreissena polymorpha distorts the other fresh-water mussels by fastening their valves with its byssus ; and balani sometimes produce strange protu- berances on the back of the cowry, to which they have attached themselves when young.* In the miocene tertiaries of Asia Minor, Professor Forbes discovered whole races of neritina, paludina, and melanopsis, with whorls ribbed or keeled, as if through the unhealthy in- fluence of brackish water. The fossil périwinkles of the Norwich Crag are similarly distorted, probably by the access of fresh water; parallel cases occur at the present day in the - Baltic. Reversed shells. Jueft-handed or reversed varieties of spiral shells haye been met with in some of the very common species, like the whelk and garden-snail. Bulimus citrinus is as often sinistral as dextral; and a reyersed variety of fusus antiquus Was more common than the normal form in the pliocene sea. Other shells are constantly reversed, as pyrula perversa, many species of pupa, and the entire genera, clausilia, physa, and triforis. Bivalyes less distinctly exhibit variations of this / * In the British Museum there is a he/iz terrestris (Chemn.) with a small stick passing through it, and projecting from the apex and umbilicus. Mr. Pickering has, in his collection, a helix hortensis which got entangled in a nut-shell when young, and growing too large to escape, had to endure the incubus to the end of its days. 38 MANUAL OF THE MOLLUSOA. kind; but the attached valve of chama has its wmbo turned to the right or left indifferently ; and of two specimens of lucina childreni in the British Museum, one has the right, the other the left valve flat. The colours of shells are usually confined to the surface beneath the epidermis, and are secreted by the border of the mantle, which often exhibits similar tints and patterns (e.g. voluta undulata, Fig. 89). Occasionally the inner strata of porcel- lanous shells are differently coloured from the exterior, and the makers of shell-cameos ayail themselves of this difference to produce white or rose-coloured figures on a dark ground.* The secretion of colour by the mantle depends greatly on the action of hight; shallow-water shells are, as a class, warmer and brighter coloured than those from deep water; and bivalves which are habitually fixed or stationary (like spondylus and pecten pleuronectes) have the upper valve richly tinted, whilst the lower one is colourless. The backs of most spiral shells are darker than the under sides; but in danthina the base of the shell is habitually turned upwards, and is deeply dyed with yiolet. Some colours are more permanent than others; the red spots on the naticas and nerites are commonly preseryed in tertiary and oolitic fossils, and even in one example (of n. sub- costata, Schl.) from Devonian limestone. Terebratula hastata, and some pectens of the car- boniferous period, retain their markings; the orthoceras angu- liferus of the Devonian beds has zig-zag bands of colour; anda terebratula of the same age, from Arctic North America, is ornamented with several rows of dark red spots. The operculum. Most spiral shells have an operculum, or lid, with which to close the aper- ture when they withdraw for shelter (See GASTEROPODA). It is developed en a particular lobe at the posterior part of the foot, Fig. 28. Zrochus ziziphinus.t * Cameos, in the British Museum, carved on the shell of cassis cornuta, are white on an orange ground ; onc. tuberosa, and madagascariensis, white upon dark claret- colour; on c. rufa, pale salmon-colour on orange; and on strombus gigas, yellow on pink. By filing some of the olives (e.g. oliva utriculus) they may be made into very different-coloured shells, 1 Trochus ziziphinus, from the original, taken in Pegwell Bay abundantly. This species exhibits small tentacular processes, neck-lappets, side-lappets, tentacular filaments, and an operculigerous lobe. STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 39 and consists of horny layers, sometimes hardened with shelly matter (Fig. 28). It has been considered by Adanson, and more recently by Dr. Gray, as the equivalent of the dextral valve of the conchi- fera; but however similar in appearance, its anatomical relations are altogether different. In position it represents the byssus of the bivalves (Lovén) ; and in function it is like the plug with which unattached specimens of bysso-arca close their aperture. —(Forbes). Homologies of the shell.* The shell is so simple a structure that its modifications present few points for comparison; but even these are not wholly understood, or free from doubt. The bivalve shell may be compared to the outer tunic of the ascidian, cut open and conyerted into separable valves. In the conchifera this division of the mantle is vertical, and the valves are right and left. In the brachiopoda the separation is horizontal, and the valves are dorsal and ventral. The monomyarian bivalves le habitually on one side (like the plewronectide among fishes) ; and their shells, though really right and left, are termed “‘upper” and ‘‘lower” yalves. The univalve shell is the equivalent of both valves of the bivalve. In the pteropoda it consists of dorsal and yentral plates, comparable with the valves of terebratula. In the gasteropoda it is equivalent to both valves of the conchifera united above.t The nautilus shell corresponds to that of the gasteropod; but whilst its chambers are shadowed forth in many spiral shells, the siphuncle is some- thing additional; and the entire shell of the cuttle-fish and argonaut f{ have no known equivalent or parallel in the other molluscous classes. The student might imagine a resemblance in the shell of the orthoceras to a back-bone. The phragmocone is the representative of the calcareous axis (or splanchno-skeleton) of a coral, such as amplexus or siphonophyllia. Temperature and hybernation. Observations on the tempera- ture of the mollusca are still wanted; it is known, however, to _yary with the medium in which they live, and to be sometimes a degree or two higher or lower than the external temperature ; * Parts which correspond in their real nature—(their origin and development)— are termed homologous ; those which agree merely in appearance, or office, are said to be analogous. 7 Compare /fissurella or trochus (Fig. 28) with lepton squamosum (Fig. 12). The disk of hipponyz is analogous to the ventral plate of hyalea and terebratula. t The argonaut shell is compared by Mr. Adams to the nidamental capsules of the whelk ; a better analogue would have been found in the raft of the ianthina, which is secreted by the foot of the animal, and serves to fort the egg-capsules, 40 MANUAL OF THE MOLLUSCA. with snails (in cool weather) it is generally a degree or two higher. The mollusca of temperate and cold climates are subject to hybernation ; during which state the heart ceases to beat, respiration is nearly suspended, and injuries are not healed. They also cestivate, or fall into a summer sleep when the heat is great; but in this the animal functions are much less inter- rvpted.—(Miiller.) Reproduction of lost parts. It appears from the experiments of Spallanzani, that snails, whose ocular tentacles haye been destroyed, reproduce them completely in a few weeks; others have repeated the trial with a like result. But there is some doubt whether the renewal takes place if the brain of the animal be removed as well as its horns. Madame Power has made similar observations upon yarious marine snails, and has found that portions of the foot, mantle, and tentacles, were renewed. Mr. Hancock states that the species of eolis are apt to make a meal off each other’s papille, and that, if confined in stale water, they become sickly and lose those organs; in both cases they are quickly renewed under favourable circumstances. Viviparous reproduction. This happens in a few species of gasteropods, through the retention of the eggs in the oviduct, until the young haye attained a considerable growth. It also appears to take place in the acephalans, because their eggs gene- rally remain within some part of the shell of the parent until hatched. Oviparous reproduction. The sexes are distinct in the most highly organised (or diecious) mollusca; they are united in the (moneectous) land-snails, pteropods, opisthobranchs, and in some of the conchifers. The prosobranchs pair; but in the dicecious acephalans, the spermatozoa are merely discharged into the water, and are inhaled with the respiratory currents by the other sex. The moncecious land-snails require reciprocal union; the limneids unite in succession, forming floating chains. The eggs of the land-snails are separate, and protected by a shell, which is sometimes albuminous and flexible, at others calcareous and brittle ; those of the fresh-water species are soft, mucous, and transparent. The spawn of the sea-snails consists of large numbers of eggs, adhering together in masses, or spread - out in the shape of a strap or ribbon, in which the eggs are arranged in rows; this nidamental ribbon is sometimes coiled up spirally, ike a watch-spring, and attached by one of its edges. The eggs of the carniyorous gasteropods are enclosed STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 41 in tough albuminous capsules, each containing numerous germs; these are deposited singly, or in rows, or agglutinated in groups, equalling the parent ani- mal in bulk (Fig. 83). The nidamental capsules of the cuttle-fish are clustered hke grapes, each con- taining but one embryo; those of the calamary are grouped in radiating masses, each elongated capsule containing 30 or 40 ova. The material with which the eggs are thus cemented together, or enyeloped, is secreted by the nidamental gland, an organ largely developed in the female gasteropods and cephalopods (Fig. 50, n). Development. The molluscan ovum consists of a coloured yolk (vitellus), surrounded by albumen. On one side of the yolk is a pellucid spot, termed the germinal vesicle, haying a spot or nucleus on its surface. This germinal vesicle is a nucleated cell, capable of producing other cells lke itself; it is the essential part of the egg, from which the embryo is formed ; but it undergoes no change without the influence of the sperma- tozoa.t . After impregnation, the germinal yesicle, which then subsides into the centre of the yolk, divides spontaneously into two ; and these again divide and subdivide into smaller and still smaller globules, each with its pellucid centre or nucleus, until the whole presents a uniform granular appearance. The next step is the formation of a ciliated epithelium on the surface of the embryonic mass; movements in the albumen become per- ceptible in the vicinity of the cilia, and they increase in strength, until the embryo begins to revolve in the surrounding fluid. Fig. 29. Spawh of Doris.* * Nidamental ribbon of Doris Johnstoni. (Alder and Hancock.) {+ No instance of ‘“partheno-genesis”? is known among the mollusca; the most “‘equivocal” case on record is that related by Mr. Gaskoin. A specimen of Aeliz lactea, Mull., from the South of Europe, after being two years in his cabinet, was dis- covered to be still living; and on being removed to a plant-case it revived, and six weeks afterwards had produced twenty young ones! } According to the observations of Professor Lovén (on Ack bivalve mollusca}, the ova are excluded immediately after the inhalation of the spermatozoa, and apparently from their influence ; but impregnation does not take place within the ovary itself. The spermatozoa of cardium pygmeum were distinctly seen to penetrate in succession the outer envelopes of the ova, and arrive at the vitellns, when the7 dis- appeared. With respect to the “germinal vesicle ;” according to Barry, it first 42 MANUAL OF THE MOLLUSCA. Up to this point nearly the same appearances are presented by the eggs of all classes of animals,—they manifest, so far, a complete ‘‘ unity of organisation.” In the next stage, the development of an organ, fringed with stronger cilia, and sery- ing both for locomotion and respiration, shows that the embryo is a molluscous animal; and the changes which follow soon point out the particular class to which it belongs. The rudimentary head is early distinguishable by the black eye-specks; and the heart by its pulsations. The digestive and other organs are first ‘‘sketched out,” then become more distinct, and are seen to be covered with a transparent shell. By this time the em- bryo is able to move by its own muscular contractions, and to swallow food; it is therefore ‘‘ hatched,” or escapes from the eco oo° Very little is known respecting the development of Brachio- pods. I. Muller has described * an embryo which, it is thought, may belong to Crania. It possessed two roundish valves of un- equal size, the dorsal being the larger. At the part where the hinge is placed in the adult was a small oyal plate. Five pairs of stiff setae projected from the mantle, ‘and four of them origi- nated from the ventral half. The edge of the mantle in the dorsal valve was beset with numerous finer setze, which curyed over upon the outside of the ventral valve. The alimentary canal filled the posterior half of the space between the valves. There were two auditory capsules and two eyes. ‘The anterior half was occupied by four pairs of cylindrical arms, surrounding a round knob, at the summit of which was the mouth. Locomotion was effected by means of the cilia enveloping the arms, which impelled the animal through the water with the mouth fore- most. No circulatory or reproductive organs could be detected. The young bivalves are hatched before they leave their parent. (See page 597) The forms they pass through present distinct differences in several families, so that even in the present state of embryological knowledge, some five or six types of development are known. yen in the same family there may bea great dis- approaches the inner surface of the vitelline membrane, in order to receive the influence of the spermatozoa ; it then retires to the centre of the yolk, and undergoes a series of spontaneous subdivisions. In M. Lovén’s account it is said to ‘* burst”? and partially dissolve, whilst the egg remains in the ovary, and before impregnation; it then passes to the centre of the yolk, and undergoes the changes described by Barry, along with the yolk, whilst the nucleus of the germinal vesicle, or some body exactly resembling it, is seen occupying a small prominence on the surface of the vitelline membrane, until the metamorphosis of the yolk is completed, when it disappears, in some unobserved manner, without fulfilling any recognised purpose. * Archiv fur Anatomie und Physiologie, 1860, p. 72; see also Annals of Nat. Hist fox 1860. STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 45 similarity, as in the case of the marine and fresh-water forms of the mytilidz. The following account refers to the type to which the young of Crenella belong. At first they have a swimming disk, fringed with long cilia, and armed with a slen- der tentacular filament (flagellum). Ata later period this disk disappears progressively as the labial palpi are developed; and they acquire a foot, and with it the power of spinning a byssus. They now have a pair of eyes situated near the labial tentacles (Fig. 30* e), which are lost at a further stage, or replaced by numerous rudimentary organs placed more favourably for vision, on the border of the mantle. The development of the young has been noticed in many of the genera of Pteropods. They are divisible into two groups: those in Pla AZ (8) . TER 2\ ere yoo, \e> = = AA Fig. 30.* which the body is surrounded with one or more rings of cilia, and those in which these rings are absent. * Fig. 50*. Fry of the Mussel.t Most of the aquatic gasteropoda are very minute when a Fig. 30. Very young fry of crenella marmorata, Forbes, high'y magnified; d, disk, bordered with cilia; 7, flagellum ; v7, valves; m, ciliated mautle. 7 Fig. 30*. Fry of mytilus edulis, after Lovén. e, eye; e’, auditory capsule ; Z ¢, 44 MANUAL OF THE MOLLUSCA. batched, and they enter life under the same form,—that which has been already referred to as permanently characteristic of the pteropoda. (Fig. 69.) The Pulmonifera and Cepha'’cpoda produce large eggs, con= taining sufficient nutriment to support the embryo until it has attained considerable size and development ; thus, the newly- born cuttle-fish has a shell half an inch long, consisting of several layers, and the bulimus ovatus has a shell an inch in length when hatched. (Fig. 31.) These are said to undergo no transformation, because their larval stage is concealed in the ege. The researches of John Hunter + into the embryonic condition of animals, led him to the conclusion that each stage in the development of the highest animals corresponded to the permanent form of some one of the inferior orders. This erand generalisation has since been more exactly defined and established by a larger induction of facts, some of which we haye already described, and may now be stated thus :— In the earliest period of existence all animals display one uniform condition; but after the first appearance of special development, uniformity is only met with amongst the mem- bers of the same primary division, and with each succeeding step it is more and more restricted. From that first step, the members of each primary group assume forms and pass through phases which have no parallels, except in the division to which each belongs. The mammal exhibits no likeness, at any period, to the adult mollusc, the insect, or the star-fish; but only to the ovarian stage of the invertebrata, and to more advanced stages of the classes formed upon its own type. And so also with the highest organised mollusca ; after their first stage they labial tentacles; s s’, the stomach; 0, branchie; h, heart ; v, vent; Z, liver; 7, renal organ ; a, anterior adductor; a’, posterior adductor ; f, foot. The arrows indicate tie incurrent and excurrent openings; between which the margins of the mantle are united in the fry. * Egg and young of bulimus ovatus, Miill. sp., Brazil, from specimens in the collec- tion of Hugh Cuming, Esq. + “In his printed works the finest elements of system seem evermore to flit before him, twice or thrice only to have been seized, and after a momentary detention to have been again suffered to escape. At length, in the astonishing preparations for his museum, he constructed it, for the scientific apprehension, out of the unspoken wpbubet of nature.”— Coleridge. b! 4 pe > ere 4 iy : “{ 3 CLASSIFICATION, 45 resemble the simpler orders of their own sub-kingdom, but not those of any other group. These are the views of Professor Owen—the successor of Hunter—by whom it has been most clearly shown and stead- fastly maintained, that the ‘‘ unity of organisation” manifested by the animal world results from the design of a Supreme In- telligence, and cannot be ascribed to the operation of a mechani- cal ‘‘ law.” CLASSIFICATION. The objects of classification are, first, the convenient and in- telligible arrangement of the species ;* and, secondly, to afford a summary, or condensed exposition, of all that is known re- specting their structure and relations. In studying the shell-fish we find resemblances of two kinds. First, agreements of structure, form, and habits; and, secondly, resemblances of form and habits without agreement of struc- ture. The first are termed relations of effinity ; the second, of analogy. Affinities may be near, or remote. There is some amount of affinity common to all animals; but, like relationships amongst men, they are recognised only when tolerably close. Resem- blances of structure which subsist from a very early age are presumed to imply original relationship ; they have been termed genetic (or histological), and are of the highestimportance. Those which are superinduced at a later pericd are of less consequence. Analogies. Modifications relating only to peculiar habits are called adaptive; or teleological, from their relation to final causes.t A second class of analogical resemblances are purely external and illusive; they have been termed mimetic (Strick- land), and, by their frequency, almost justify the notion that a certain set of forms and colours are repeated, or represented in every class and family. In all artificial arrangements, these mimetic resemblances have led to the association of widely dif-. ferent animals in the same groups.{ Particular forms are also yepresented geographically§ and geologically,|| as well as sys- tematically. * At least 20,000 recent, and 16,000 fossil species of molluscous animals are known. { For example, the paper nautilus, from its resemblance to carinaria, was long sup- posed to be the shell of a nucleobranch, parasitically occupied by the “ ocythoé.” $e. g. Aporrhais with strombus, and ancylus with patella. § Monoceros imbricatum and buccinum antarcticum take the place, in South America, of our common whelk and purple, and solen gladiolus and solen amerzcanus of our solen siliqua and ensis. | The frequent recurrence of similar species in successive strata may lead beginners to attribute too much to the influence of time and externai circumstances; but suck impressions digappear with further experience. 46 MANUAL OF THE MOLLUSCA. In all attempts to characterise groups of animals, we find that in advancing from the smaller to the larger combinations, many of the most obvious external features become of less ayail, and we are compelled to seek for more constant and comprehen- sive signs in the phases of embryonic development, and the condition of the circulating, respiratory, and neryous systems. Species. All the specimens, or individuals, which are so much alike that we may reasonably believe them to have descended from a common stock, constitute a species. It is a particular provision for preventing the blending of species, that hybrids are always barren; and it is certain, in the case of shells, that a great many kinds have not changed in form from the tertiary period to the present day,—a lapse of many thousand years,—and through countless generations. When individuals of the same brood differ in any respect, they are termed varieties ; for example, one may be more exposed to the light, and become brighter coloured; or it may find more abundant food, and grow larger than the rest. Should these peculiarities become permanent at any place or period,—should all the specimens on a particular island or mountain, or in one sea, or geological formation, differ from those found elsewhere, such permanent variety is termed a race ; just as in the human species there are white and coloured races. The species of some genera are less subject to variation than others; the nucule, for example, although very numerous, are always distinguishable by good characters. Other genera, like ammonites, terebratula, and tel- lina, present a most perplexing amount of variation, resulting from age, sex, supply of food, variety of depth, and of saltness in the water. And further, whilst in some genera every pos- sible variety of form seems to have been called into existence, in others only a few, strikingly distinct forms, are known. Genera are groups of species, related by community of struc- ture in all essential respects. The genera of bivalves have been _ characterised by the number and position of their hinge teeth ; those of the spiral univalyes, by the form of their apertures ; but these technical characters are only valuable so far as — indicate differences in the animals themselves. Families are groups of genera, which agree in some more general characters than those which unite species into genera. Those which we have employed are mostly modifications of the artificial families framed by Lamarck, a plan which seemed more desirable, in the present state of our knowledge, than a subdivision into yery numerous families, without assignable characters. _———e' CLASSIHICATION. 47 The orders and classes of mollusca have already been referred to; those now in use are in most cases natural. It has been sometimes asserted that these groups are only scientific contrivances, and do not really exist in nature but this is a false as well as a degrading view of the matter. The labours of the most eminent systematists have been directed to the discovery of the subordinate yalue of the characters deriy- able from every part of the animal organisation ; and, as far as their information enabled them, they have made their systems expressive ‘“‘of all the highest facts or generalisations in natural history.”’—( Owen.) M. Milne Edwards has remarked, that the actual appearance of the animal kingdom is not like a well-regulated army, but like the starry heayens, over which constellations of various magnitude are scattered, with here and there a solitary star which cannot be included in any neighbouring group. This is exceedingly true; we cannot expect our systematic groups to have equal numerical yalues,* but they ought to be of equal structural importance; and they will thus possess a symmetry of order, which is superior to mere numerical regu- larity. All the most philosophic naturalists have entertained a belief that the development of animal forms has proceeded upon some regular plan, and have directed their researches to the discovery of that ‘‘reflection of the Divine mind.” Some haye fancied that they have discovered it in a mystic number, and have ac- cordingly converted all the groups into jfives.t We do not underyalue these speculations, yet we think it better to describe things so far only as we know them. Great difficulty has always been found in placing groups according to their affinities. This cannot be effected in—-the way in which we are compelled to describe them—a single series; for each group is related to all the rest; and if we extend the representation of the affinities to very small groups, any arrangement on a plane surface would fail, for the affinities radiate in all directions, and the ‘‘ network”’ to which Fabricius likened them, is as insufficient a comparison as the *‘ chain” of older writers. * The numerical development of groups is enversely proportional to the bulk of the tudividuals composing them.—( Waterhouse.) 7 The guinarians make out five molluscous classes by excluding the tunicata ; the same end would be attained in a more satisfactory manner by reducing the pteropods to the rank of an order, which might be placed next to the opistho-branchs. ¢ The quinary arrangement of the molluscous classes reminds us of the eastern 48 MANUAL OF THE MOLLUSCA. NOMENCLATURE. The practice of using two names—generic and specific—fo1 each animal, or plant, originated with Linnzeus; therefore no scientific names date further back than his works. In the con- struction of these names the Greek and Latin languages are preferred by the common consent of all countries. Synonyms. It often happens that a species is named, or a genus established, by more than one person, at different times, and in ignorance of each other’s labours. Such duplicate names are called synonyms ; they have multiplied amazingly of late, and are a stumbling-block and an opprobrium in all branches of natural history.* One very common estuary shell rejoices in the following variety of titles :— Scrobicularia piperata (Gmelin sp.). Trigonella plana (Da Costa). Mactra Listeri (Awct.). Mya Hispanica (Chemnitz). Venus borealis (Pennant). Lutraria compressa (Zamarck). Arenaria plana (Megerle). As regards specific names, the earliest ought certainly to be adopted, with, however, the following exceptions :— 1. MS. names; which are admitted by courtesy. 2. Names given by writers antecedent to Linnzeus. 3. Names unaccompanied by a description or figure. 4, Barbarisms ; or names inyolying error or absurdity.} It is also very desirable that names haying a general (Euro- pean) acceptation should not be changed on the discovery of earlier names in obscure publications. emblem of eternity—the serpent holding its tail in its mouth. The following diagram is offered as an improved circular system :— { FISHES. } : / Di-branchiata, 3 Nucleo- Tetra- 3 Opistho- Proso- 3 Aporo- Pulmo- : Pallio- Lamelli- Hetero-branchiata. F [ZooPHYTES.] g * In Pfeiffex’s Monograph of the Helicide, a family containing seventeen genera, no less than 330 genemz synonyms are enumerated; to this list Dr. Albers, of Berlin, has added another hundred of his own invention! ; + This subject was investigated and reported upon by a committee of the British — Association in 1842. ABBREVIATIONS. 49 With respect to genera, those who believe in their real exist- ence as ‘‘ ideas of the creating mind,” will be disposed to set aside many random appellations given to particular shells without any clear enunciation of their characters ; and to adopt later names, if bestowed with an accurate perception of the grounds which entitle them to generic distinction.* Authority for specific names. The multiplication of synonyms haying made it desirable to place the authority after each name, another source of eyil has arisen; for several naturalists (fancy- ing that the genus maker, and not the species maker, should enjoy this privilege) have altered or divided almost every genus, and placed their signatures as authorities for names given half a century or a century before by Linneeus or Bruguiere. The majority of naturalists have disowned this practice, and agreed to distinguish by the addition of ‘“‘sp.” the authorities fcr those specific names whose generic appellations have been altered. The type of a genus should be the species which best exhibits the characters of the group, but it is not always easy to follow out this rule; and consequently the first on the list is often put forward as the type. ABBREVIATIONS. Etym., etymology; Syn., synomym; Distr., distribution ; MS., unpublished ; Sp., species; B. /., in the British Museum. Distr., Norway—New Zealand; including all intermediate seas. Joss., Lias-chalk: imples that the genus existed in these and all intermediate strata. Chalk—; means that the genus has existed from the chalk up to the present time. Depth—50 fins. implies that the genus is found at all depths between low-water mark and 50 fathoms. Oceqrae Girrents— —~Mountains 1 to 27 Land Provinces \ 10 I ope My tales odors ee Se [re ee ( GEOGRAPHICAL DISTRIBUTION. 51 (6) Neotropical or South American region: West India Islands, South Mexico, Central and South America, Galapagos. and Falkland Isles. These divisions apply to the land, but it is probable that they will help to throw hght on the boundaries of the natural marine provinces. As will be seen, each of the above regions includes several of the proyinces adopted in this work. ‘The Land Provinces hitherto proposed have been chiefly founded on botanical grounds, but the evidence afforded by insects and the higher classes of animals contirms the oxistence of these divisions. The Marine Provinces have also been investigated by botanists ; and the striking peculiarities of the fees have been taken into account as well as the distribution of shell-fish and corals. In order to constitute a distinct province it is considered necessary that at least one-half the species should be peculiar, a rule which applies equally to plants and animals. Some genera and sub-genera are hmited to each province, but the proportion is different in each class of animals and in plants.* Specific areas. Species yary extremely in their range, some being limited to small areas, while others, more widely diffused, unite the local populations into fewer and larger groups. Those species which characterise particular regions are termed ‘endemic ;”’ they mostly require peculiar circumstances, or possess small means of migrating. The others, sometimes called ‘‘ sporadic,” possess great facilities for diffusion, like the lower orders of plants propagated by spores, and more easily meet with suitable conditions. The space over which a species is distributed is called a ‘“‘ centre,” or, more properly, a specific area. ‘The areas of one-half the species are smaller (usually much smaller) than a single province. In each specific area there is frequently one spot where indi- viduals are more abundant than elsewhere; this has been called the ‘‘ metropolis” of the species. Some species which appear to be nowhere common can be shown to have abounded formerly ; and many probably seem rare only because their head-quarters are at present unknown.—(Lorbes.) Specific centres are the points at which the particular species are supposed to have been created, according to those who believe that each has originated from a common stock (p. 46) ; * The genera of plants amount to 20,000, and consist on an average of only four species apiece! The genera of shells commonly admitted are only 400 in number, and average forty species each. It follows that the areas of the molluscan genera (ceteris paribus) ought to be ten times as great as those of plants. 52 MANUAL OF THE MOLLUSCA, these can only be known approximately in any case. The doctrine that each species originated from a single individual, or pair, created once only, and at one place, derives strong con- firmation from the fact that so ‘‘many animals and plants are indigenous only in determinate spots, while a thousand others might haye supported them as well.’’* Generic areas. Natural groups of species, whether called genera, families, or orders, are distributed much in the same manner as species; ¢ not for the same reason, since their con- stituents are not related by descent, but apparently from the intention of the Creator. Sub-generic areas are usually smaller than generic; and the areas of orders and families are, as a matter of course, larger than those of the included genera. But it is necessary to remember that groups of the same denomination are not always of equal value ; and since species vary In range it often happens that specific areas of one class or family are larger than generic areas of another. The smallest areas are usually those of the forms termed aberrant; the typical groups and species are most widely distributed.—( Waterhouse.) ‘*When a generic area includes a considerable number of species, there may be found within it a point of maximum (metropolis), around which the number of species becomes less aud less. A genus may have more centres than one. It may have had unbroken extension at one period, and yet in the course of time and change, may haye its centre so broken up * Mrs. Somerville’s Physical Geography, ii. 95. + “ What we call class, order, family, genus, are all only so many names for genera of various degrees of extent. Technically a genus is a group to which a name (as Rives) is applied: but essentially, Exogens, Ranunculacee, Ranunculus, ave genera of different degrees. *“One of the chief arguments in favour of the zaturalness of genera (or groups), is that derived from the fact that many genera can be shown to be centralised in definite geographical areas (Erica, for example); 7z.e. we find the species gathered all, or mostly, within an area, which has some one point where the mazximwn number of species is developed. “ But, in geographical space, we not unfrequently find that the same genus may have two or more areas, within each of which this phenomenon of a point of maximum number of species is seen, with fewer and fewer species radiating, as it were, from it. “In time, however (or, in other words, in geological distribution), so far as we know, each generic type has had an unique and continuous range. When once a generic type has ceased it never re-appears. ““A genus is an abstraction, a divine idea. The very fact of the centralisation of | groups of allied species, z.e. of genera, in space and time, is sufficient proof of ‘his, Doubtless we make many so-called genera that are artificial; but a true genus is natural; and, as such, is not dependent on man’s will.”—Z. Forbes. (See An. Nat Hist, July, 1852, and Jan., 1855, p. 45.) : GEOGRAPHICAL DISTRIBUTION. a0 that there shall appear to be out-lying points. When, how- eyer, the history of a natural genus shall have been traced equally through its extension in time and space, it is not impossible that the area, considered in the abstract, will be found to be necessarily unique.’”’—(Lorbes.) To illustrate the doctrine of the unity of generic areas Professor Forbes has given seyeral examples, showing that some of the most exceptional cases admit of explanation and confirm the rule. One of these relates to the genus Mitra, of which there are 420 species; it has its metropolis in the Philippine Islands, and extends by the Red Sea to the Mediterranean and West Africa, the species becoming few, small, and obscure. Far uway from the rest a single species is found on the coast of Greenland. But this very shell occurs fossil in Ireland along with another mitra now living in the Mediterranean. Another case is presented by the genus Panopea, of which the eleven lying species are widely separated. Of this genus above 100 fossil species are known, distributed over many places within the wide area, on whose margin the relics of this ancient form of life seem to linger like the last ripple of a circling wave.* According to this view the specific centres are scattered thickly over the whole surface of the globe ; those of the genera more thinly distributed; and the points of origin of the large groups become fewer in succession, until we have to estimate ‘the probable position or scene of creation of the primary divisions themselves; and are led to speculate whether there may not have been some common focus—the centre of centres -—from which the first and greatest types of life have emanated. Boundaries of Natural History Provinces. The land provinces are separated by lofty mountains, deserts, seas, and climates; whilst the seas are divided by continents and influenced by the physical character of coast-lines, by climates and currents. These ‘‘natural barriers,” as they were called by Buffon, retard or altogether preyent the migrations of species in particular directions. Influence of Climate. Diversity of ana has been the popular explanation of most of the phenomena of geographical . distribution, because it is so well known that some species require a‘tropical amount of warmth, whilst others can endure a great variety of temperature, and some only thrive amidst the rigours of the arctic regions. ‘The character of the yegeta- tion of the zones of latitude has been sketched by Baron Hum- * The most sfriking and conclusive instances may be met with in the distribution of the highest classes of vertebrate animals. 54 MANUAL OF THE MOLLUSCA. boldt ; Fabricius and Latreille have divided the world into climatal Insect-provinces ; and Professor E. Forbes has con- structed a map of the homoiozoic belts or zones of marine life. To all these the remark of Mr. Kirby is applicable—that any division of the globe ints provinces, by means of equivalent parallels and meridians, wears the appearance of an artificial and arbitrary system, rather than of one according to nature. Professor Iorbes has been careful to point out that although the ‘‘Faunas of regions under similar physical conditions bear a striking resemblance to each other’—this resemblance is produced, ‘‘not by identity of species, or eyen of genera, but by representation ”’ (p. 48). Origin of the Natural History Provinces. Mr. Kirby appears to have been the first to recognise the truth that physical conditions were not the primary causes of the zoological pro- vinces, which he “‘ regarded as fixed by the will of the Creator, rather than as regulated by isothermal] lines.” * Mr. Swainson also has shown that the ‘‘ circumstances connected with tem- - perature, food, situation, and foes, are totally insufficient to account for the phenomena of animal geography,” which he attributes to the operation of unknown laws.t The most important contribution towards a knowledge of these ‘‘ unknown laws”’ has been made by Professor HE. Forbes, who was perhaps the first naturalist ever in a position to avail himself of the great storehouse of facts accumulated by geolo- gists, respecting the distribution of organic life in ‘‘ the former world.” This subject will be referred to again in connection with the subject of Fossil Shells; meanwhile it may be stated that, according to this evidence, the Faunas of the Provinces are of various ages, and that their origin is connected with former (often very remote) geological changes, and a different distribution of land and water oyer the surface of the globe. MARINE PROVINCES. Amongst the genera of marine shells there are some which have been considered particularly indicative of climate. From the Arctic list the following may be taken as examples of the shells of high latitudes; those marked * being found in the southern as well as in the northern hemisphere :— ® Tntroduction to Entomology. + Treatise on Geography and Classification of Animals, Lardner’s Cabinet Cyclo peedia. MARINE PROVINCES. 55 Buccinum. Velutina. *Crenella. *Chrysodomus. Lacuna. *Yoldia. *Trophon. *Margarita. *Astarte. Admete. — Cyprina. *Trichotropis. *Rhynchonella. Glycimeris. The following haye been thought peculiar to the warmer re- gions of the sea: Nautilus. Conus, Columbella. Perna. Rostellaria, Harpa. Cyprea. Vulsella, Triton. Oliva. Nerita. Tridacna, Cancellaria. Voluta. Spondylus. Crassatelia. Terebra. Margineila. Plicatula. Sanguinolar‘a. But it must not be inferred that these genera were always characteristic of extreme climates. On the contrary, the whole of them haye existed in the British seas at no very remote geo- logical period. Jthynchonella and Astarte were formerly ‘‘ tropi- cal shells ;” and since the period of the English chalk-formation there have been living Nautili in the North Sea, and Cones and Olives in the ‘‘ London basin.” It is not true that the same species have been at one time tropical, at another temperate, but the genera have in many instances enjoyed a much wider range than they exhibit now. Some of the “tropical” forms are more abundant and extend farther in the Southern hemisphere ; several large Volutes range to the extremity of South America, and the largest of all inhabits New Zealand. The tropical and sub-tropical provinces might be naturally grouped in three principal divisions, yiz., the Atlantic, the Indo-Pacific, and the West-American,—divisions which are bounded by meridians of longitude, not by parallels of latitude. The Arctic proyince is comparatively small and exceptional ; and the three most southern Faunas of America, Africa, and Australia differ extremely, but not on account of climate. If only a small extent of sea-coast is examined, the character of its mollusca will be found to depend very much upon the nature of the shore, the tides, depth, and local circumstances, which will be referred to again in,another page. But these peculiarities will disappear when the survey is extended to a region sufficiently large to include eyery ordinary variety of condition. It has been stated that each Fauna consists of a number ot peculiar species, properly, more than half;’and of a smaller number which are common to some‘other provinces. By ascer- taining the direction of the tides and currents, and the circum- stances under which the species occur, it may be possible ta determine to which province these more widely diffused mollusca 56 MANUAL OF THE MOLLUSCA. originally belonged. And when species occur both recent and fossil it is easy to perceive the direction in which their migra- tions have taken place. The Fauna of the Mediterranean has been critically examined by Prof. Forbes and M. Philippi, with this result,—that a large proportion of its population has migrated into it from the At lantic, and a smaller number from the Red Sea, and that the supposed peculiar species are diminishing so rapidly with every new research in the Atlantic, that it can no longer rank as a province distinct from the Lusitanian. . When the Faunas of the other regions haye been tested in the same manner, and disentangled, the result will probably be the establishment of a much greater number of provinces than we have ventured at present to indicate on the map. It may be desirable to notice here the extraordinary range attributed to some of the marine species. These statements must be received with great hesitation; for when sufficiently investigated, it has usually proved that some of the localities were false, or that more than one species was included. ‘The following are given by Dr. Krauss in his excellent monograph of the South African Mollusca :— Ranella granifera : Red Sea, Natal, India, China, Philippines, New Zealand. Triton olearius : Brazil, Mediterranean, Natal, Pacific. Purpura lapillus: Greenland, (Senegal, Cape). Venus verrucosa: (W. Indies), Brit. Senegal, Canaries, Mediterranean, Red Sea, Cape (Australia). Octopus vulgaris: Antilles, Brazil, Europe, Natal, Mauritius, India. Argonauta argo: (Antilles), Medit., Red Sea, Cape. Lucina divaricata is said to be ‘‘ found on the shores of Europe, India, Africa, America, and Australia.” (Gray.) In this case seyeral species are confounded. The rock-boring Sawicava has been carried to all parts of the world in ballast, and it remains yet to be ascertained whether the same species occurs in a liying state beyond the Arctic Seas and North Atlantic. Lastly, the money cowry is always catalogued as a shell of the Mediterranean and Cape, although its home is in the Pacific, and it has no other origin in the Atlantic than the occasional wreck of one of the ships in which such vast quantities of the little shell are annually brought to this country to be exported _ again to Africa, ARCTIC PROVINCE. 5% I. ARcTIC PROVINCE. The North Polar Seas contain but one assemblage of Mollusca, whose Southern limit is formed by the Aleutian Islands in the Pacific, but in the North Atlantic is determined chiefly by the boundary of floating ice, descending as low as Newfoundland on the West, and thence rising rapidly to Iceland and the North Cape. A yery complete general account of the Arctic Mollusca is given by Dr. Middendorff;* those of Greenland have been catalogued and described by Otho Fabricius and Moller ;+ and more recently by Mérch ;{ 158 species are enumerated by Middendorff, and 202 by Mérch. Scattered notices occur in the Annals of Natural History,§ and the Supplements to the Narratives of the Arctic Voyagers,—Phipps, Scoresby, Franklin, Back, Ross, Parry, and Richardson. The existence of the same marine animals in the Kamtchatka Sea and Baffin’s Bay was long since held to prove at least a former North-West passage ; but the occurrence of recent sea-shelis in banks far inland rendered it probable that even recent elevation of the land in Arctic America might have much reduced the passage. During the ‘‘ Glacial period,” this Arctic Sea, with the same fauna, ex- tended over Britain ; over Northern Europe, as far as the Alps and Carpathians; and over Siberia, and a considerable part of North America. The shells now living in the Arctic Seas, are found fossil in the deposits of ‘‘ Northern Drift,”’ over all these countries ; and a few of the species yet linger within the bounds of the two next provinces, especially in tracts of unusual depth. The Arctic shells have mostly a thick greenish epidermis (p. 33); they occur in very great abundance, and are remarkably subject to variation of form, a circumstance attributed by Professor H. Forbes to the influence of the mixture of fresh water produced by the melting of great bodies of snow and ice. ARCTIC SHELL-FISH. R. Russian Lapland. F. Finmark. I. Iceland. G. Greenland. D. Davis Straits (west coast). B. Behring’s Straits. O. Ochotsk. * British species (living). ** British species (fossil). Octopus granulatus. G. - ameena, G. Cirroteuthis Miilleri. G. *Ommastrephes todarus. F. Newf. Rossia palpebrosa. G. P. Regent Inlet, Onychoteuthis Bergii. F, B. Limacina arctica, G. O. ze Fabricii. G. * Malaco-zoologia Rossica ; Mem. del’ Acad. Imp. des Sc, Petersb, T. 6, pt. 2, 1949. 7 Index Molluscorum Greenlandie. Hafn. 1842. t Fortegnelse over Grénlands Bliddyr in H. Rink: Grénland geographisk og statis- tisk beskrevet, ii. Bind. 1857. § Hancock, An, Nat. Hist. vol. 18, p. 323, pl. 5, Dé 58 MANUAL OF Spirialis stenogyra. F. =n balea, G. *Clio borealis. N. Zemia. G. *Nassa incrassata. F. *Buccinum undatum, var. Kara. O. “9 hydrophanum. D. Prince Regent Inlet. p tenebrosum. R, G. B. * ae Humphreysianum. R. G. ¥* C. St. Lawrence. A, glaciale. Kava, O. C. Parry. G. Spitzbergen. Buecinum angulosum. N. Zemla. Icy C. Spitz. “3 tenue. N. Zemla. G. “ Groenlandicum. D. ~ undulatum. G. + scalariforme. G. ** a ciliatum. G. ” boreale (Leach). Baffin’sB. + sericatum. D. P. Refuge. * ” Hollbollii (Mangelia, Mol.) Gare. * “5 Dalei. R. B. Pleurotoma, 13 sp. G. *Fusus antiquus. N. Zemla. B. **® ,, carinatus. G. ,, contrarius. R. O. s, deformis. R. Spitz. ** ,, despectus. G. Spitz. » heros. C. Perry. » latericeus. G. #* ,, Sabini. D. Mass. » pellucidus. D. » Kroyeri. G. Spitz. » decemcostatus. B. Newf. * ,, Bemiciensis. R. B. »» Spitzbergensis. Spitz. * ,, Islandicus. F. * gracilis. F. R. G. B. **'Trophon clathratus. R. G. B. a* #® >» Gunneri. F. G. ** » craticulatuy. R. I. G@ * » Sarvicensis. F. » harpularius. F, U.S. * 5, truncatus. *Purpura lapillus. R. G. B. Mangelia, 9sp. G. a decussata. D. +*Bela turricula, F. G. oS ay Sub 1Oee (Ee **Mitra Groenlandica. G. **Admete viridula, R. Spitz, G. B. ay cyaneum. F. D. G. Icy » scalariformis. Spitz. Newf. B. THE MOLLUSCA. + *Trichotropis borealis. F. G. B. Prince Regent Inlet. ‘ conica. G. - insignis. B. 5 bicarinata. B. *Natica helicoides. R. G. B. ** ., clausa, F. N. Zemla. G. Mel- ville Id. P. Regent Inlet. B. » pallida. R. O. » flava. N. Zemla. B. Newf. * 4, pusilla (groenlandica). G. Norway. Spitz. nana. G. #Velutina lievigata. R. B. * . flexilis. F. halal oe zonata. R. » lanigera. G. Lamellaria prodita. F. 3 Grenlandica. G, B. **Scalaria Greenlandica. F. G. B. ** ,, borealis (Eschrichti). G. Amaura candida. G. Chemnitzia albula. G. **Mesalia lactea. G. **Turritella polaris. G. Aporrhais occidentalis. *Littorina obtusata. R. ey tenebrosa. N.Zemla. D. + Greenlandica. G. F. G. Labrador. Bis palliata (arctica). G. “ limata. F. *Lacuna vincta. R. Newf. G. » labiosa, F. P. Refuge. * , crassior. BR: » @lacialis. G. * 5 pallidulal (G- * , puteolus. F. Newfi. » irigida, F. solidula. F. Ravers castanea. R. G. Rissoa scrobiculata. G. » globulus. G. » saxatilis. G. *Skenea planorbis. G. F. **Margarita cinerea. F. U.S. * + undulata. R. G. * ~ alabastrum. F. * "3 helicina. G. White Sea. Spitz, a sordida. R. Spitz. G. B. + umbilicalis. D. B. ‘5 Harrisoni. D. glauca. G. » Vahlii. G. * as costulata. G. *Puncturella Noachina, F, G. *Acmeea testudinalis, K, Iceland, G, ARCTIC SHELL-FISH. **Lepeta ceca. G. F. Spitz. C. Eden. Pilidium rubellum, F. G. D. Patella,4sp. G. *Chiton ruber. F. G. Spitz. was, albus. FE. G. Dentalium entale. Spitz. Bulla Reinhardi. G. » subangulata. G. *Cylichna alba. G. F. Spitz. ee turrita. G. *Philine scabra. Norway. G. s punctata (MOU.) G. Doris liturata. G. acutiuscula. G. » Obvelata. G. *Dendronotus arborescens. F. G. ZEolis bodocensis. G. Tergipesrupium. G. Euplocaraus Holbdllii. G. ” *Terebratulina caput-serpentis. Spitz. F. Mass. Medit. *Waldheimia cranium. F. - septigera. F. Terebratella Spitzbergensis. Sp. ae Labradorensis. Labr. **Rhynchonella psittacea. R. Baffin’s Bay, 76° N. Melville, I. B. *Crania anomala. Spitz. *Anomiasquamula. R. * , aculeata. R. **Pecten Islandicus. F, N. Zemla. Spitz. G. B. St. Lawrence. vitreus. F. Arctic America. » Greenlandicus. R. Spitz. D. Limatula sulcata. G. F. *Mytilus edulis. R. G. B. *Modiolamodiolus. R. B. *Crenella discors (levigata). G. D. N. Zemla. bad * » 4ecuSsata. R. G. = ,» £«UXigra. N. Zemla, R. G. D. $* faba. G. » vitrea. -G. Arca glacialis. P. Regent Inlet. Nucula corticata. G. me inflata. G. D. Leda buccata. G. macilenta. G. ” 59 **Leda minuta(Fabr.) F. Spitz. @ D. *® ,, lucida. F. (= navicularis? Spitz.) * ,, pygmea. G. F. Siberia. **Yoldia arctica Gr. (myalis). G. U.S. Spitzbergen. lanceolata (arctica B. & 8.) Icy Cape. limatula. F. U.S. Kamt. hyperborea, Spitz. thracieformis (angularis). Mass. truncata, Br. (Portlandica, Hit.) P. Refuge. Arctic America. ** Astarte borealis (arctica). F. Iceland. G. ¥* ** G. R* “c ** ,, semisulcata (corrugata). Kara Sea. N. Zemla. Spitz. P. Regent Inlet. C. Parry. Icy Cape. * , €elliptica. F. G. Spitz. * , sulcata. R. N. Zemla. O. ** 4, crebricosta. F. Spitz. Newf. » crenata. P. Regent Inlet. » Warhami. Davis Str. » globosa. G. * compressa. N. Zemla. G. » Banksii. Spitz. Baffin’s Bay *Cardium edule var. rusticum, R, Islandicum. N. Zemla. G. Greenlandicum., Kara. Spitz, C. Parry. St. Lawrence, ~ is elegantulum, G. *Cryptodon flexuosus. G. F. *Turtonia minuta. G. F. *Cyprina Islandica. R. Labrador. **Cardita borealis. Mass. O, **Tellina calcarea. F. G. B. ” ¥* ** ,, Grenlandica, (= Balthica, Le N. Zemla. Spitz. F. G. B. lel edentula. B. bby *Mya truncata. R. Spitz. G. C. Parry. B. ** ,, Uddevallensis. St. Lawrence. D. P. Regent Inlet. Melville I. ~~ * ,, arenaria. N. Zemla. G. O. **Saxicava rugosa (arctica), N. Zemla, Spitz. G. C. Parry. B. (Panopea) Norvegica. White Sea. O. Macheera costata. Labrador. O. Glycimeris siliqua. C. Parry. Newf. *Lyonsia Norvegica. F. O arenosa. G. D. P. Refuge. we ” ** ,, rostrata (pernula). F. Spitz, Arctic |**Thracia myopsis. G. America, Pandora glacialis, Spitz, Baff, (Leach), 60 MANUAL OF THE MOLLUSCA. II. BorEAL PROVINCE. The Boreal Province extends across the Atlantic from Nova Scotia and Massachusetts to Iceland, the Faeroe and Shetland Islands, and along the coast of Norway from North Cape to the Naze. Of the 289 Scandinavian shells catalogued by Dr. Lovén,* 217, or 75 per cent. are common to Britain, and 1387 range as far as the North coast of Spain. | The boreal shells of America are described by Dr. Gould.t From these lists it appears that out of 270 sea-shells found on the coast of Massachusetts north of Cape Cod, more than half are common to Northern Europe. Many of the species, it is believed, could only haye extended their range so distantly by means of continuous lines of con- necting coast, now no longer in existence.t+ BOREAL SHELLS COMMON TO EUROPE AND NORTH AMERICA. * British Species. *Teredo navalis. *Lucina borealis. *Pholas crispata. ? 4, £divaricata. *Solen ensis. *Cryptodon flexuosus. * (Panopeea) Norvegica. * Astarte borealis, *Mya arenaria. * ,, triangularis? (quadrans, G.) *,, truncata, * Cyprina Islandica. *Thracia phaseolina (Conradi, Couth). ? (Cardium Islandicum, U.S.—N. Zemla), Mactra ponderosa (ovalis, G.) Yoldia limatula. ? Montacuta bidentata, » arctica, Gr. (= myalis), *Turtonia minuta. *Leda pygmea, ? Kellia rubra. * ,, caudata. ? Lepton nitidum (fabagella, Conr. ?) ? 4, navicularis (lucida, Lovén ?) *Saxicava rugosa (arctica). *Nucula tenuis. Tellina solidula, var. (fusca, Say). *Mytilus edulis. * 4, calcarea (sordida, Couth). *Modiola modiolus. ———e * Index Molluscorum Scandinavie; extracted from the “ Ofversiot af K. Vet. Akad. Forh.” 1846. The climate of Finmark is much less severe than Russian Lap- land; Hammerfest has an open harbour all the year. 7 Report on the Invertebrata of Massachusetts. 1841. t Forbes, Memoirs of the Geol. Survey, i. p. 379. Sir John Richardson, when speaking of the.cod-tribe and turbot-tribe, says:—“Most of the fish of this order feed on or near the bottom, and a very considerable number of the species are common to both sides of the Atlantic, particularly in the higher latitudes, where they abound. It does not appear that their general diffusion ought ta be attributed to migration from their native haunts, but rather that in this respect they are analogous to the owls, which, though mostly stationary birds, yet include a greater proportion of species common to the old and new worlds than even the most migratory families. Several of the Scomberoidee (Mackerel-tribe) which feed on the surface, have been previously noted as traversing many Gegrees of longitude in the Atlantic: but the existence of the ground-feeding Gadoidee in very distant localities must be attributed to a different cause, as it is not probable that any of them wander out of soundings or ever approach the mid-seas,”’"—Report Zool, N, America, p, 218, - %) BOREAL PROVINCE. 61 *Crenella nigra. eel a discors, L. oe decussata (glandula, Tot.) Pecten Islandicus. ? Ostrea edulis (borealis, Lam. ?) *Anomia ephippium. * , aculeata. » squamula? *Terebratulina caput-serpentis. *Rhynchonella psittacea. *Dendronotus arborescens. Polycera Lessonii ? ? Amphisphyra hyalina (debilis‘ ) Cylichna alba (triticea, C.) * = obtusa (pertenuis). *Philine quadrata (formosa, St.) *Chiton cinereus. * ,, Mmarmoreus. ees) CLUDE. aun 5, leeVis. * , asellus. * albus. Shentalinm (entale, L.?) ? Lepeta ceca (candida, C.) *Acmea testudinalis (amoena, S.) *Puncturella Noachina. * Adeorbis divisus (= Skenea serpuloides). Margarita cinerea. * + costulata ? (Skenea). * -- helicina. *Margarita undulata, * ¥ alabastrum (= occidentalis ?) ere greenlandica. », tenebrosa (vestita). » palliata? *Lacuna vincta (divaricata). * ,, puteolus (Montagui). *Skenea planorbis. *Velutina levigata. a: zonata. *Lamellaria perspicua. *Natica helicoides. » clausa. * ,, pusilla. *Scalaria greenlandica. (Ianthina communis). Odostomia producia. Cancellaria (admete) viridula. *Trichotropis borealis. *Fusus antiquus (tornatus). * ,, islandicus. * 4, propinquus. » Prosaceus. *Trophon muricatus. * ,, clathratus. » scalariformis. » harpularius. * Purpura lapillus. *Buccinum undatum. 3 “ (Gominella) Dalei. *Bela tuyricula. * ,, Treveiyana, * ,, rufa (Vahlii) ? *Ommastrephes sagittatus is also common to both sides of the North Atlantic. The genera, Machera, Glycimeris, Solemya, Mesodesma (deauratum), Cardita, and Crepidula, are peculiar to the American side of the Boreal Province. Several other species now living on the coast of the U. States occur fossil in England: e.g. Trophon cinereus, Say.,is believed to be the Fusus Forbesi, Strickland, of the Isle of Man; others are marked in the Arctic list. Ill, CELTIc PROVINCE. The Celtic province, as described by Prof. E. Forbes, includes the British island coasts, Denmark, Southern Sweden, and the Baltic.* The fauna of this region (which includes the principal * The great work of Messrs. Forbes and Hanley is the standard text book on British Testacea . A new work on British Mollusca is now being prepared by war, 62 MANUAL OF THE MOLLUSCA. herring-fisheries) is essentially Atlantic; many of the species are of ancient origin, and occur fossil in the Pliocene. The British mollusca described by Forbes and Hanley amount to 682, viz. :— 14 (15) Cephalopoda. 100 Pulmonifera. 175 (172) Acephala. 220 (254) Marine Univalves. 4 (5) Pteropoda. 73 (73) Tunicata. 91 (100) Nudibranchiata. 5 (7) Brachiopoda. Of this number two-thirds of the Nudibranchia, 55 marine uni- valves, and 7 bivalve shell-fish, are, at present, only known in British seas; but as most of these are minute or ‘‘critical”’ species, it is considered they will yet be met with elsewhere. In 1857, Mr. M‘Andrew was acquainted with 626 marine mol- luscs, as indicated by the figures in brackets in the summary just given. A few of the species belong to the Lusitanian province, whose northern limits include the Channel Islands, and just impinge upon our coast. Phasianella pullus. Murex corallinus. Cytherea chione. Haliotis tuberculata. Avicula Tarentina, Petricola lithophaga. Truncatella Montagui. Galeomma Turtoni. Venerupis irus. Oncidium celticum, Pandora rostrata. Cardium rusticum, L. (tuber- Bulla hydatis. Ervilia castanea. culatum). Volva patula. Mactra helvacea. Of the Gasteropoda 54 are common to the seas both north and south of Britain; 52 range farther south, but are not found northward of these islands ; and 34 which find here their south- ern limit occur not only in Northern Europe, but most of them in Boreal America. Nearly half of the bivalves range both north and south of Britain; 40 extend southward only, and about as many more are found in Scandinavia, 27 of them being common to N. America. (forbes.) In the lists of Arctic and Boreal shells the British species are distinguished by an asterisk. According to Mr. M‘Andrew’s estimate in 1850, 406 British shell-bearing mollusca were then known, of which 217 or 53 per cent. were common to Scandinavia. 246 or 61 9 as North of Spain. 227 or 56 os > S. Spain and Medit. 97 or 24 a 35 Canary Islands. G. Jeffreys. The Nudibranchiata alone have been more fully described in the publications of the Ray Society, by Messrs. Alder and Hancock. For the marine zoology of the coasts of Denmark the “ Zoologia Danica” of O, F, Miiller is still the most important work. LUSITANIAN PROVINCE. 63 The following are at present peculiar to Britain :— Assiminea, sp. Odostomia, 19 sp. ? Montacuta ferruginosa. Jeffreysia, sp. Buccinum fusiforme, Argiope cistellula. Otina oiis. Fusus Berniciensis. Pecten niveus. Rissoa, sp. » Turtoni. Syndosmya tenuis. Stylifer turtoni. Natica Kingii. Thracia villosiuscula. The most common edible species are :— Ostrea edulis. Mytilus edulis. Fusus antiquus. Pecten maximus. Cardium edule. Littorina littorea. » opercularis, Buccinum undatum, Amongst the species characteristic of the Celtic provyince—or most abundant in it—are the following :— Trophon nuricatus. Littorina littoralis. Venus striatula. Nassa reticulata. Trochus Montagui. » casina. Natica Montagui. » millegranus. Donax anatinus. » monilifera. 0) tumidus: Solen ensis. a Hitida: Patella vulgata. Pholas candida. Velutina levigata. 5, pellucida. Mactra elliptica. Turritella communis. Acmea virginea, » solida Aporrhais pes-pelecani. Chiton cinereus. Periploma preetenuis. Rissoa cingillus. Scaphander lignarius. Thracia distorta. Scalaria Trevelyana. Tellina crassa. Syndosmya prismatica. The wide expanse of the Baltic affords no shell-fish unknown to the coasts of Britain and Sweden. The water is brackish, becoming less salt northward, till only estuary shells are met with, and the Littorine and Limnezans are found living to- gether, as in many of our own marshes. This scanty list is taken from the Memoirs of Dr. Middendorff and M. Boll. Buccinum undatum. Neritina fluviatilis, Tellina Balthica. Purpura lapillus. Limnea auricularia. » tenuis. Nassa reticulata. » ovata. Scrobicularia piperata. Littorina littorea. Mytilus edulis. Mya arenaria, Patella (tarentina), Donax (trunculus). » truncata. Hydrobia muricata. Cardium edule var. Meyer and Mobius collected the following species at Kiel :— Chiton cinereus. Rissoa parva. Cerithium reticulatum, Acmea testudinalis. Littorina littorea. Nassa reticulata. Rissoa labiosa. > littoralis. Buccinum undatum, » inconspicua, - tenebrosa. Fusus antiquus. a Ulva. Lacuna vincta. » ventrosa. » pallidula. IVY. LvsITANIAN PROVINCE. The shores of the Bay of Biscay, Portugal, the Mediterranean, and N. W. Africa, as far as Cape Juby, form one important province, extending westward in the Atlantic as far as the Gulf- 64 MANUAL OF THE MOLLUSCA. weed bank, so as to include Madeira, the Azores, and Canary Islands. * In the Atlantic portion of the province occur the following genera, not met with in the Celtic and Boreal seas, although two of them, Mitra and Mesalia, occur on the coast of Green- land :— Argonauta. Cancellaria. Auricula. — Philonexis. Sigaretus. Pedipes. Spondylus. Chiroteuthis. Crepidula. Ringicula Avicula. eed Mesalia, Umbrella. Solemya. Conus. Vermetus. Glaucus. Chama. Pleurotoma. Fossarus, -_— Crassatella. Marginella. Planaxis. Carinaria. Lithodomus. Cymba. Litiopa. Firola. Ungulina. Mitra. Truncatella. Atlanta. Galeomma,. Terebra. Solarium. Oxygyrus. Cardita. Columbella. Bifrontia. - Cytherea. Pisania. Turbo. Cleodora. Petricola. Dolium. Monodonta, Cuvieria, Venerupis. Cassis. Hailiotis. Creseis, Mesodesma. Triton. Gadinia. oa Ervilia. Ranella. Siphonaria. Megerlia, Panopea. Spain and Portugal. The coast of Spain and Portugal is less known than any other part of the proyince, but the facilities for exploration are in some respects greater than in the Mediterranean, on account of the tides. Shell-fish are more in demand as an article of food here than with us, and the Lisbon market afforded to Mr. M‘Andrew the first indication that the genus Cymba ranged so far north. On the coasts of the Asturias and Gallicia, especially in Vigo Bay, Mr. M‘Andrew obtained, by dredging, 212 species, of a * Tn the northern part of the Lusitanian province are the Pilchard fisheries; in the Mediterranean, the Tunny, Coral, and Sponge fisheries. The Gulf-weed banks (represented in the map) extend from 19° to 47° in the middle of the North Atlantic, covering a space almost seven times greater than the area of France. Columbus, who first met with the sargasso about one hundred miles west of the Azores, was apprehensive that his ships would run upon a shoal. (Hum- boldt.) The banks are supposed by Professor E. Forbes to indicate an ancient coast- line of the Lusitanian land-province, on which the weed originated. Dr. Harvey states that species of Sargassum abound along the shores of tropical countries, but none exactly correspond with the Gulf-weed (S. bacciferum). It never produces fructifica- tion—the “berries” being air-vesicles, not fruit—but yet continues to grow and flourish in its present situation, being propagated by breakage. It may be an abnormal condition of S. vulgare, similar to the varieties of Facus nedosus (Mackayi) and F. vesiculosus which often occur in immense strata; the one on muddy sea-shores, the other in salt marshes, in which situations they have never been found in frnctification, (Manual of British Alge, Intr. 16, 17.) es ee LUSITANIAN PROVINCE. 65 somewhat northern character, 50 per cent. of them being com- mon to Norway, and 86 per cent. common to the south of Spain. On the southern coast of the Peninsula 353 species were obtained, of which only 28 per cent. are common to Norway and 51 per cent. to Britain. The identical species are chiefly amongst the shells dredged from a considerable depth (35—50 fathoms) ; the littoral species have a much more distinct aspect. The shells of the coast of Mogador are generally identical with those of the Mediterranean and Southern Peninsula. Canary Islands. The shells of the Canaries collected by MM. Webb and Berthelot,* and described by M. D’Orbigny, amount to 124, to which Mr. M‘Andrew has added above 170. Of the 300 species 17 per cent. are common to Norway, 382 per cent. to Britain, and 68 per cent. to the coasts of Spain and the Medi- terranean. ‘Two only are W. Indian shells, Neritina viridis and Columbella cribaria. Of the African shells found here, and nof met with in more northern localities, the most remarkable are ;— Crassatelia divaricata. Ranella levigata. Cymba proboscidalis. Cardium costatum. Cassis flammea. Conus betulinus. Lucina Adansoni. » testiculus. » Prometheus. Cerithium nodulosum. Cymba Neptuni, » Guinaicus. Murox saxatilis, ” porcina. »» papilionaceus. Madeira. Mr. M‘Andrew obtained 156 species at Madeira, of which 44 per cent. are British, 70 per cent. common to the Mediterranean, and 83 to the Canaries. Amongst the latter are the two W. Indian shells before mentioned, and the follow- ing African shells :— Pedipes. Mitra fusca. Patella crenata. -Littorina striata. » zebrina. » guttata. Solarium. Marginella guancha, » Lowei. Scalaria cochlea. Cancellaria. » Candei. Natica porcellana, Monodonta Bertheloti, | Pecten corallinoides. Azores. Amongst the littoral shells which range to the Azores, are Pedipes, Littorina striata, Mitra fusca, and Ervilia castanea; the other species obtained there are Jusitanian. (M‘ Andrew.) : The Mediterranean fauna is known by the researches of Poli, Delle Chiaje, Philippi, Verany, Milne-Edwards, Professor E. Forbes, and Deshayes. In its western part it is identical with that of the adjacent Atlantic coasts; the number of species diminishes eastward, although reinforced by a considerable * Hist. Naturelle des Iles Canaries; the list of shells is reprinted, with the additions made by Mr, M‘Andrew, as one of the Catalogues of the British Museum, 66 MANUAL OF THE MOLLUSCA. number of new furms as yet only known in the Mediterranean ; and a few accessions (about 30) of a different character from the Red Sea. The total number of shell-bearing species is esti- mated at 600, viz. :— Cephalopoda, .......scseesee 1 Nucleobranchiata... 6 Lamellibranchiata ......200 IPECTOPOGS csiccccevesccecrss 13 Gasteropoda ......... 370 Brachiopoda ....sescesesree 10 On the coast of Sicily, M. Philippi has found altogether 619 marine mollusca, viz. :— SIVAIVES srpsrundeasoenses cores 188 PteropOda .cccecoveree LD Gasteropod@ sesscesesserees 319 BrachiOpodar .-ccescevessans 10 Nudibranchs ......... 54 Cephalopoda, ....ecccceee cove Of the 522 which are provided with shells, 162 have not been found fossil, and are presumed to be of post-tertiary origin, so far as concerns their presence in the Mediterranean. The re-~ maining 360 occur fossil in the newer tertiary strata, along with nearly 200 others which are either extinct or not known lying on those coasts ; a few of them are living in the warmer regions of Senegal, the Red Sea, and the West Indies :— Senegal. Antilles. Red Sea. Lucina columbella. Lucina pennsylvanica. Argonauta hians. Cardium hians. Vermetus intortus. Dentalium elephantinum, Terebra fusca. Terebra duplicata. Morocco. Phorus agglutinans. Trochus strigosus. Niso terebellum. Pecten medius. Diplodonta apicalis. Most of them, howeyer, are of northern origin, such as :— Saxicava rugosa. Tellina crassa. Rhynchonella psittacea. (Panopesa) Norvegica. Cyprina Islandica. Patella vulgata. Mya truncata. Leda pygmea, Eulimella Scille. Periploma preetenuis. Limopsis pygmea. Buccinum undatum, Lutraria solenoides, Ostrea edulis. Fusus contrarius. Of the 522 Sicilian testacea, about 35 (including 10 oceanic species) are common to the West Indies—if the species haye been correctly determined ; 28 are stated, with more probability, to be common to West Africa, including Murex Brandaris and other common species; 74, including Murex trunculus, are com- mon to the Red Sea; Crania ringens cannot be distinguished from the species found in New South Wales (Davidson); and Columbella corniculum ranges from the north coast of Spain to Australia, the specimens from these distant localities being only distinguishable as geographical varieties. (Gaskoin.) Six other species are included in Menke’s Australian Catalogue, but re- quire verification. The following gencra, nine of which are naked molluscs, are — | 4 LUSITANIAN PROVINCE: 67 supposed to be now peculiar to the Mediterranean; the small number of species show they are aberrant or expiring forms. Cassidaria, and Thecidiwm are ancient, widely-distributed genera, and the Mediterranean TZ'hecidiwm occurs fossil in Brit‘any and the Canaries. Thysanoteuthis, 2 sp. Sceureous, 1. Morrisia, 2. Verania, 1. Pleurobranchea, 1. Thecidium, 1. Dosidicus, 1. Tethys, l. Scacchia, 2, Doridium, 1. Cassidaria, 6 Icarus, 1. Pedicularia, 1. The genera Fasciolaria, Siliquaria, Tylodina, Notarchus, Verti- cordia 2 Clavagella, and Crania, occur only in this portion of the Lusitanian province. Amongst the peculiar species are :— Nassa semistriata, Argiope cuneata. Artemis lupinus. Fusus crispus. Clavigella angulata. Trigona nitidula. Tylodina Rafinesquii. Spondylus Gussonii. Lucinopsis decussata. Crania rostrata, Astarte bipartita. Aigean Sea. Prof. E. Forbes obtained 450 species of mollusca in the Aigean, belonging to the following orders :— Cephalopoda ...........000 4 Nudibranchs ......... 15 Brachiopodai..<..cceccecceas 1 o EECEODOUR os. cesceasecoessse 8 Opisthobranchs...... 28 Lamellibranchs ......... 143 Nucleobranchs ............ 7 Prosobranchs ......... 217 PUNICALAG lees anaseravs stereo Of these 71 were new species, but several have since been found in the Atlantic, and eyen in Scotland.* The only marine air-breather met with was Auricula myosotis. Black Sea. Inthe northern part a few Aralo-Caspian shells are found, otherwise the Black Sea only differs from the Medi- terranean in the paucity of its species ; Dr. Middendorff enume- rates 68 only. The water is less salt, and there is no tide, but a current flows constantly through the Dardanelles to the Mediterranean.t+ Lorenzt found 178 molluscs at Quarnero, of which 75 were bivalyes, and 88 univalyes; 75 of them extended their range into the AXgean Sea, 58 into the Boreal province. Few only appeared to be peculiar to the Adriatic. * Trans. Brit. Assoc. (for 1£43), 1844, p. 130. ¢ Accurrent from the Atlantic sets in perpetually through the Straits of Gibraltar, and there is scarcely any tide ; it only amounts to one foot at Naples and the Euripus, two feet at Messina, and five at Venice and the Bay of Tunis. } Physikalische Verhaltnisse und Vertheilung der Organismen im Quarnerischen Golfe. Wien, 1863, 6a MANUAL OF THE MOLLUSCA. V. ARALO-CASPIAN PROVINCE. The only inland salt-seas that contain peculiar shell-fish aro the Araland Caspian. The shells chiefly consist of a remarkable group of Cockles which burrow in the mud (see fig. 213, p.402). No explorations haye been made with the dredge, but other species, probably still existing in these seas, have been found in the beds of horizontal limestone which form their banks and extend in all directions far over the sfeppes. This hmestone is of brackish water origin, being sometimes composed of myriads of Cyclades, or the shells of Dreissena and Cardium, as in the islets near Astrakhan. It is believed to indicate the former existence of a great inland sea, of which the Aral and Caspian are remnants, but which was larger than the present Mediter- ranean at an age previous to that of the Mammoth and Siberian Rhinoceros. The present level of the Caspian is 83 feet below that of the Black Sea; that of the Aral has been stated to be 117 feet higher than the Caspian, but is probably not very different; their waters are only brackish, and in some parts drinkable. The steppe limestone rises to a level of 200—300 feet above the Caspian; it spreads eastward to the mountains of the Hindoo Kush and Chinese Tartary, southward oyer Daghestan and the low region E. of Tiflis, and westward to the northern shores of the Black Sea.. The extent to which it has been traced is represented by oblique lines on the map.* Some of the Caspian shells still exist in the Sea of Azof and the estuaries of the Dnieper and Dniester. Our information upon this seldom-visited region is derived from the works of Pallas, Eichwald,+ Krynicki,t Middendorff, and Sir Roderick Mur- chison. Aralo-Caspian Shells. A, Aral; C, Caspian ; B, Black Sea. The Species marked * are found also in the Steppe limestone. *Cardium edule, L. C. (very small) B. Baltic. » edule, var. (rusticum, Chemn.) A. C.B. Icy Sea. *Didacna trigonoides, Pal. C. (Azof. M. Hommaire). » Hichwaldi, Kryn. (crassa, Eich.) C. B. (Nikolaieff). Monodacna Caspia, Eich. C. +,» | pseudo-cardium, Desh. (pontica, Eich.) B. Adacna leviuscula, Eich. C. » Vitrea, Bich. C. A. * From a sketch kindly prepared by Professor Ramsay. ¢ Geogr. des Kaspischen Meeres, des Kaukasus und des Siidlichen; Busslands. Berlin, 1830. Fauna Caspio-Caucasica, 1841. { Bull. des Nat. Moscow, 1837, WEST AFRICAN PROVINCE. 69 *Adacna edentula, Pallas. C. “e plicata, Eich. C. B. (Dniester, Akerman, Odessa). » colorata, Eich. C. B. (Azof, Dnieper). * Mytilus edulis, L. C. ©. (not in Middendorff’s list). »» latus,Chemn. B. *Dreissena polymorpha, Pal. C. B. Paludinella stagnalis, L. (pusilla Eich.) C. B, (Odessa) Ochotsk. See WVarrabilis, Bich: C; * Neritina liturata, Eich. C. on sea-weed. * Rissoa Caspia, Eich. C. oblonga, Desm. B. cylindracea, Kryn. B.* ” ”? The following species are described by Hichwald, from the steppe limestone. (Murchison, Russia, p. 297.) Donax priscus. Paludina” Triton. 3 exigua. Mactra Caspia. Monodacna propinqua. Ris soa conus. » Karagana. 53 intermedia. s dimidiatus. Cyclas Ustuertensis. 33 Catillus, _ Bullina Ustuertensis. Mytilus rostriformis. Adacna prostrata. No other inland bodies of salt water are known to have peculiar marine shells; those of the modern deposits, in Meso- potamia (at Sinkra and Warka), collected by Mr. W. K. Loftus, are species still abounding in the Persian Gulf.t VI. WEstT AFRICAN PROVINCE. The tropical coast of Western Africa is rich in conchological treasures, and far from being wholly explored. The researches of Adanson,{ Cranch (the naturalist to the Congo expedition§), and the officers of the Niger expedition, have left much to be done. Dr. Dunker has described 149 species in his Index Moll. Guinec, coll. Tams. Cassel, 1853. At St. Helena, Mr. Cuming collected 16 species of sca-shells, 7 of them new. Littorina Helene is found on the shore of St. Helena, and 2%. miliaris and Nerita Ascensionis, at Ascension, * The Velutina (Limneria) Caspiensis. A. Ad. was founded on a specimen of Limnea Gebleri, Midd. (1851), from Bernaoul, Siberia. tT A species of coral (Porites elongata, Lam.), now living at the Seychelles, has been said to be found in the Dead Sea (v. Humboldt's Views of Nature, Bohn ed. p. 260); also Melania costata and M. Jordanica, according to M. Schubert. t Hist. Nat. de Senegal, 4dto. Paris, 1757. This able but eccentric naturalist Gestroyed the utility of his own writings by refusing to adopt the bi-nomial nomen- clature of Linn £vus, and employing instead the most barbarous chance-combinations of letters he could invent. § Appendix to Captain Tuckey’s Narrative (1818), by Dr. Leach. 70 Onych>steuthis, 3 sp. Cranchia, 2 sp. Strombus rusaceus. Triton ficoides. Ranella quercina. Dolium tessellatum. Harpa rosea. Oliva hiatula. Pusionella. Nassa Pfeifferi. Desmoulinsia. Purpura nodosa. Rapana bezoar, XM urex vifulinus. 4 angularis. » megaceros. » rosarius. >» duplex. 3 cornutus, Clavella? filosa. jie otra. Lagena nassa. Terebra striatula. = ferruginea. ? Halia priamus. Mitra nigra. West’ African Shells. Marginella Persicula. Pleurotoma mitriformis. Tomella lineata. Clavatula mitra. 9 coronata. x bimarginata. 45 virginea. Conus papilionaceus. » genuinus. », testudinarius. ;, achatinus. monachus. Natica fulminea. Cyprea stercoraria. 55 picta. Vermetus lumbricalis. Cerithium Adansonii. Turritella torulosa. Mesalia. Littorina punctata. Collonia. Clanculus villanus. Haliotis virginea. 7 coccinea. Nerita Senegalensis. MANUAL OF THE MOLLUSCA. Pecten © bbus, Arca vn r cosa, », senilis, Cardium ringens, i costatum, Lucina columbel!a. Ungulina rubra. Diplodonta rosea. Cardita ajar. Artemis africana. 5). COLAO: Cyclina Adansonii. Trigona bicolor. » tripla. Cytherea tumens, eS africana, Venus plicata, Tellina. Strigilla Senegalensis. Gastrana polygona, Mactra depresza. » rugosa, » hitida, Pholas clausa. Tugonia anatina. —es Cymba. », Ascensionis. Discina radiosa, VII. SoutH AFRICAN PROVINCE. The fauna of South Africa, beyond the tropic, possesses few characters In common with that of the western coast, and is more like the Indian Ocean fauna, as might be expected from the direction of the currents. But, together with these it has a large assemblage of marine animals found nowhere else, and the ‘‘Cape of Storms” forms a barrier between the populations of the two great oceans, scarcely less complete than the far-pro- jecting promontory of South America. The coast is generally rocky, and there are no coral-reefs ; accumulations of sand are frequent, and sometimes very extensive, like the Agulhas Bank. The few deep-sea shells which have been obtained off these banks possess considerable interest, but explorations in boats are said to be difficult, and often impossible on account of the surf. Shells from the Cape are too frequently dead and water- worn specimens picked up on the beach. The shell-fish of South © Africa haye been collected and described by Owen Stanley, | Hinds, A. Adams, and especially by Dr. Krauss, who has © INDO-PACTFIC PROVINCE. 71 published a very complete monograph.* Of 400 sea-shells recorded in this work, aboye 200 are peculiar, and most of these belong to a few littoral genera.. Only 11 species are common to the coast of Senegal, whilst 18 are found in the Red Sea; 14 species are said to be found in Europe; all the others, not pecu- liar, exist on the E. coast of Africa. South African Shells. Panopzea natalensis. Patella apicina. Cominella tigrina. Solen marginatus. », longicosta. Bullia levissima, Mactra spengleri. » pectinata, &c, 3; achatina. Gastrana ventricosa. Siphonaria, 5 sp. » natalensis. Nucula pulchra, Hinds. Pupillia (aperta). Nassa plicosa. (L’Agulhias bank, 70 fm.) Fissurella, 10 sp. + capensis. Pectunculus Belcheri, 120 Crepidula, 4 sp. Cyclonassa Krauss{. fm. Haliotis sanguinea. Eburna papillaris. Modiola Capensis. Delphinula granulosa. Columbella, 5 sp. 6 pelagica, Forbes. os cancellata. Ancillaria obtusa. Septifer Kraussi. Trochus, 22 sp. Mitra, 5 sp. Turbo sarmaticus. Imbricaria carbonacea. Terebratulinaabyssicola, _Littorina Africana 7 sp. Voluta armata. 132 fm. Phasianella, 6 sp. » Scapha. Terebratella (Kraussia). Bankivia varians. 5, abyssicola, 132 fm, a rubra. Turritella, 4 sp. Marginella rosea. = cognata. Pleurotoma, 6 sp. Trivia ovulata. yy pisum. Clionello (sinuata). Cypreea, 22 sp. a Deshayesii, Typhis arcuatus. Luponia algoénsis. 120 fm. Triton dolarius. Cyprovulum (capense). 3 fictilis, 50-60 fm. Conus, 8 sp. Chiton, 16 sp. Harpa crassa. — Patella, 20 sp. Cominella ligata. Octopus argus. 3 cochlea. “ lagenaria. Sepia, 4 sp. 3, compressa, or limbosa. The following are stated to be common to the Cape and Eurs- pean seas.t Saxicava (arctica?) Greenland, Medit. Chama gryphoides, Medit. Red Sea. Tellina fabula, Brit. Medit. Pecten pusio, Brit. Lucina lactea, Medit. Red Sea. » fragilis, Medit. Diphyllidia (lineata?) N. Brit. Medit. Venus verrucosa, W. Indies? Brit. Senegal, Eulima nitida, Medit. Canaries, Red Sea, Australia ? Purpura lapillus ?? (not in Medit.) Tapes puilastra, North Sea. Nassa marginulata. » geographica, Medit. Octopus vulgaris? Brit. _ Arca iactea, Medit. Argonauta argo, Medit. VIII. Inpo-Paciric Province. This is by far the most extensive area over which similar shell-fish and other marine animals are distributed. It extends from Australia to Japan, and from the Red Sea and cast coast * Die Siidafrikanischen Mollusken, 4to. Stutt. 1848. _ * Marks of doubt are added to some of the species, and others are omitted. ae “ff 72 _ MANUAL OF THE MOLLUSCA. of Africa to Easter Island in the Pacific, embracing three-fifths of the circumference of the globe and 45° of latitude. This great region might, indeed, be subdivided into a number of smaller provinces, each having a particular association of species and some peculiar shells, such as the Red Sea, the Persian Gulf, Madagascar, &c.; but a considerable number of species are found throughout the province, and their general character is the same.* Mr. Cuming obtained more than 100 species of shells from the eastern coast of Africa, identical with those collected by himself at the Philippines, and in the eastern coral islands of the Pacific.t This is pre-eminently the region of coral reefs, and of such shell-fish as affect their shelter. The number of species inhabiting it must amount to several thou- sands. The Philippine Islands have afforded the greatest variety, but their apparent superiority is due, in a measure, to the researches of Mr. Cuming; no other portion of the province has been so thoroughly explored.t Amongst the genera most characteristic of the Indo-Pacific, those marked (*) are wholly wanting on the coasts of the At- lantic, but half of them occur fossil in the older tertiaries of Europe. Those in italics are also found on the west coast of America. *Nautilus. 4*Magilus, Stomatella. Hemicardium. *Pteroceras. *Melo. Gena. *Cypricardia. *Rimella. Mitra. *Broderipia. *Cardilia. *Rostellaria. *Cylindra. *Rimula. * Verticordia. *Seraphs. *Imbricaria. *Neritopsis. *Pythina. Conus. Ovulum. *Scutellina. Circe. Fleurotoma. * Pyrula (type). *Linteria. *Clementia. *Cithara. *Monoptygma. *Dolabella. *Glaucomya. * Clavella. Phorus. *Hemipecten. *Merde. *Turbinella (typ.) Siliquaria. *Placuna. Anatinella. Cyllene. *Quoyia. *Malleus. Cultellus. Eburna. *Tectaria. *Vulsella. *Anatina. Phos. Imperator. *Pedum. *Chena. Dolium. Monodonta. * Septifer. *Aspergillum. Harpa. Delphinula. *Cucullea. *Jouannetia. *Ancillaria, Liotia. *Hippopus. *Lingula. €Ricinuia. *Stomatia. *Tridacna. Discina. The strictly littoral species vary on each great line of coast : - for example, Littorina intermedia and Tectaria pagodus occur on ; # rt A * See Mrs. Somerville’s Physical Geography, ii. p. 233. 7 Journal Geol. Soc. 1846, vol. ii. p. 268. t Mr. Cuming collected 2,500 species of sea-shells at the Philippines, and estimates i the total number at 1,000 more. The genera most developed are Conus, 120 sp.;_ Preurotoma, 100; Mitra, 250; Columbelia, 40; Cyprea, 50; Natica, 50; Chiton, 30; Zellina, 50, INDO-PACIFIC PROVINCE. 738 the east coast of Africa; Littorina conica and melanostoma, in the Bay of Bengal; Littorina sinensis and castanea, and Haliotis venusta, on the coast of China; Littorina scabra and H. squamata, in N. Australia; H. asinina, New Guinea; and LZ. picta, at the Sandwich Islands. Red Sea (Erythreean). Of the 408 mollusca of the Red Sea, collected by Ehrenberg and Hemprich, 74 are common to the Medit., from which it would seem that these seas have communicated since the first appearance of some existing shells. Of the species common to the two seas 40 are Atlantic shells which haye migrated into the Red Sea by way of the Medit., probably during the newer pliocene period; the others are Indo-Pacific shells which ex- tended their range to the Mediterranean at an earlier age. The genera wanting in the Medit. but existing in the Red Sea, show most strikingly their diversity of character, and the affinity of the latter to the Indian fauna, Pieroceras. Ancillaria, Siphonaria. Limopsis. Strombus, 8 sp. Harpa. Placuna. Tridacna. Rostellaria. Ricinula, Plicatula,. Crassatella. Turbinella, Magilus. Pedum. Trigona. Terebra. Pyramidella. Malleus. Sanguinolaria. Eburna. Parmophorus. Vulsella. Anatina. Oliva. Nerita. Perna. Aspergillum. Other genera become abundant, suchas Conus, of which there are 19 species in the Red Sea, Cyprea 16, Mitra 10, Cerithium 17, Pinna 10, Chama 5, Circe 10. Persian Gulf. The marine zoology of the Persian Gulf and adjoining coast has not been yet explored.* The following shells were picked up on the beach at Kurrachee by Major Baker, with many others evidently new, but not in a satisfactory state for descrip- tion. (1850.) Rostelaria curta. Purpura persica. Sigaretus sp. Murex tenuispina var. » carinifera. Odostomia sp. Pisania spiralis. Columbella blanda, Phorus corrugatus. Ranella tuberculata. Oliva subulata. Planaxis sulcata. 9 spinosa. yy Indusica. Imperator Sauliz, » crumena. » ancillaroides. Monodonta sp. Triton lampas. Cyprea Lamarckii. Haliotis sp. Bullia sp. 3 ocellata. Stomatella imbricata. Eburna spirata. Natica pellis-tigrina, ~ sulcifera. 4 The “Brindled Cowry ” (Cyprea princeps), from the Persian Gulf, was valued at £50, E 74 MANUAL OF THE MOLLUSCA. Fissurella Ruppellii. ne Indusica. 5 salebrosa. is dactylosa. a funiculata, Pileapsis tricarinatus. Nerita ustulata. Dentalium octangulatum. Ringicula sp. Bulla ampulla. Anomia achzeus. “ enigmatica. Pecten sp. Spondylus sp. Plica‘ula depressa. Mytilus canaliculatus. Arca obliquata. » sculptilis, &c. Chama sp. Lucina s». Cardium fimbriatum. > latum. Cardium impolituin. ‘5 pallidum. 3) assimile. Venns pinguis. a RICOLs 3, purpurata. Meroé Solandri. » effossa. Trigona trigonella ? Artemis angulosa. “ exasperata. » subrosea? Venerupis sp. Petricola sp. Tapes sulcosa. », Malabarica. Cypricardia vellicata. Cardita crassicostata ? » calyculata. » Tankervillii. Mactra 7Egyptica, &c. Tellina angulata. Tellina capsoides, Mesodesma Horsfieldii, Psammobia sp. Syndosmya sp. Semele sp. Solen sp. Solecurtus politus. Donax scortum, » scalpellum. Sanguinolaria diphos, a violacea. ” sinuata. Corbula sp. Diplodonta sp. Anatina rostrata. Pandora sp. Martesia sp. Pholas australis. » Bakeri, Desh. » orientalis. (Meleagrina v. p.416). At the Cargados or St. Brandon shoals, north of Mauritius, Voluta costata, Conus verrucosus, Pleurotoma virgo, and Turbinella Belcheri have been obtained by dredging. Collections of marine shells have been made at Madagascar and the Mascarene Islands by Sganzin, and at the Seychelles by Dufo. The number obtained at the latter place was 263, of which 220 were univalves. Two of the univalves, yiz., Doliwm galea and Cyprea heivela, and two of the bivalves, are found in the Mediterranean. IX. AUSTRALO-ZELANDIC PROVINCE, Most remote from the Celtic seas, this province is also most unlike them in its fuuna, containing many genera wholly un- known in Europe, either living or fossil, and some which occur fossil in rocks of a remote period. The province includes Ney Zealand, Tasmania, and extra-tropical Australia, from Sandy Cape, on the east, to the Swan River. The shells, which are nearly all peculiar, have been catalogued by Gray,* Menke,+ and Forbes.t Of the following genera some are peculiar (*), others attain here their greatest development :— * Travels in New Zealand, by Dr. E. Dieffenbach. 8vo., London, 1843, ¢ Moll. Nov. Hollandiz, 1843. $ Narrative of the Voyage of H.M.S. Zattlesnake, 1846-50, by J Macgillivray, Supplement by Professor E. Forbes. APONIC PROVINCE. 75 *Pinnoctopus, * Macgillivraia. Cypricardia, Imperator. *Struthiolaria. * Amphibola, Mesodesma. Monoptygma. Phasianella. *Trigonia. Terebratella, Siphonaria. Elenchus. *Chamostrea, Spirula. Pandora. Bankivia. * Myadora. Oliva. Anatinella. Rotella. *Myochama. Conus. Clavagella. *Macroschisma. Crassatella. Voluta. Placunomia. Parmophorus. Cardita. Terebra. Waldheimia. Risella. Circe. Fasciolaria. Crania. Some of the genera of this province are only met with else- where at a considerable distance :— Solenella —Chili. Panopea—Japan. Monoceros—Patagonia. Bankivia—Cape. Kraussia—Cape. Solemya—Medit. Rhynchonella—Arctic seas, Trophon—Fuegia; ,, Assiminea—India; Brit. Amongst the littoral shells of South Austraha are Haliotis elegans, H. rubicunda, and Littorina rugosa. Haliotis tris and Littorina squalida are found on the shores of N. Zealand; and Cyprovula wmbilicata in Tasmania. Mr. Gray’s New Zealand list amounts to 104 marine species, among which are three yolutes, including V. magnifica, the largest of its genus; Strombus troglodytes, Ranella argus, the great Triton variegatus ; 6 Cones (all doubtful), Oliva erythros- toma, Cypreea caput-serpentis, Ancillaria australis, Imperator heliotropium, Chiton monticularis, &e. Venus Stutchburyi and Modiolarca trapezina have been found at Kerguelen’s Id. and Patella illuminata at the Auckland Ids. X. JAPONIC PROVINCE. The Japanese Islands and Corea represent the Japonic pro- vince. Our knowledge of its molluscan fauna is still scanty, notwithstanding the successful researches of Mr. Adams. Up- wards of 130 species were collected in the harbour of Decima, by Dr. Nuhn, of which 113 were Prosobranchiates. Octopus areolatus. Sepia chrysopthalma. Sepioia Japonica. Conus Sieboldi. Pleurotioma Coreanica. Terebri serotina. - stylata. Eburna Japonica. Cassis Japonica. Murex eurypterus. » rorifluus. = plorator. - Burneti. Purpura, 5 sp. Fusus, Cancellaria noduiifera. Mitra. Strombus corrugatus. Cyprzea fimbniata. re miliaris. Mangelia, 4 sp. Triforis, 5 sp. Natica, 5 sp. Trochus, 15 sp. Radius birostris. Cevithium longicaudatum. Imperator Guilfordie. ES Haliqtis Japonica. yy discus. » gigantea. Bulla Coreanica. Siphonaria Coreanica. Pecten asperulatus. » Japonicus. Spondylus Cumingii. Nucula mirabilis. » Japonica. Cardium Bechei. Crassatella compressa. Diplodonta alata. = Coreanica, 76 MANUAL OF THE MOLLUSCA. Isocardia Mcltkiana. Artemis Sieboldi. , Panopeea Japonica. Venus Japonica. » Japonica, Terebratulina Japonica, Cyclina orientalis. Circe Stutzeri. a angusta. Cytherea petechialis. Tapes Japonica, Waldheimia Grayi. Artemis sericea. Petricola radiata, Terebratella Coreanica. 5 biluuata. Solen albidus. ap rubeila. XI, ALEUTIAN PROVINCE. The Boreal province is represented on the northern coasts of the Pacific, where, according to Dr. Middendorff, the same genera and many identical species are found. In addition to those indicated in the Arctic list (p. 57), the following species occur at the Shantar Ids. in the Sea of Ochotsk (O), Saghahen, the Kuriles (K), Aleutians and Sitka (S). Patella (scurra). S. Fusus Behringii. Acmea,3sp. S. 6 aeru, 2AS Pilidium commodum. O, » luridus. S. Paludinella. 3sp. O. Buccinum undatum var. Schantaricum, Littorina, 6sp. O. K.S. 5S simplex. O. Turritella Eschrichtii. O. = Ochotense. Margarita sulcata, A. “6 cancellatum. A. Trochus,6sp. S. ‘i ovoides. O. Scalaria Ochotensis. Pisania scabra. A. Crepidula Sitchana. Bullia ampullacea. O. 7) minuta.. 'S. Onychoteuthis Kamtschatica. grandis. A. Fissurella violacea. S. Terebratella frontalis. O. 3 aspera. S. Placunomia macroschisma. O, Haliotis Kamtschatica. Pecten rubidus. S. 3 aquatilis. K. Crenella vernicosa. O. Velutina coriacea. K. - cultellus. Kamt. » cryptospira. O. Nucula castrensis. S. Trichotropis inermis. S, Pectunculus septentrionalis. A. Purpura decemcosiata. (Mid.) S. Cardita borealis. O. 5» Sreycineti. O.S. Cardium Nuttalli. S. *n septentrionalis. S. + Californicum. S. Pleurotoma Schantarica. Saxidomus Petiti. S. a simplex. O. » giganteus. S. Murex monodon. S. Petricola cylindracea. S. 5s lactuca. °S: = gibba. S. Fusus (Chrysodomus) Sitchensis, Tellina lutea. A. nasuta. S. ss decemcostatus. A. » edentula. A. »» schantaricus. Lutraria maxima. S. The influence of the Asiatic coast-current is shown in tha presence of two species of Haliotis, whilst affinity with the fauna of W. America is strongly indicated by the occurrence of Patella (scurra), three species of Crepidula, two of Fissurella, and species of Bullia, Placunomia, Cardita, Saxidomus, and Petricola, which~ are more abundant, and range farther north than their allies in the Atlantic. — ; Beni, ALEUTIAN PROVINCE: Ti Additional information on the fauna of this province has been recently supplied by Mr. Lord, the naturalist to the British North American Boundary Commission Expedition, and by Dr. Kennerley, the naturalist to the American North-west Boundary Exploring Expedition. The results obtained are discussed by Dr. 2. P. Carpenter.* Provinces on the Western Coast of America. The mollusca of the Western coast of America are equally distinct from those of the Atlantic and those inhabiting the central parts of the Pacific. Mr. Darwin states in his Journal (p. 391) that ‘‘ not one single sea-shell is known to be common to the Islands of the Pacific and to the west coast of America,” and he adds that ‘‘ after the comparison by Messrs. Cuming and Hinds of about 2000 shells from the Eastern and Western coasts of America, only one single shell was found in commen, namely the Purpura patula, which inhabitsthe West Indies, the coast of Panama, and the Gal- lapagos.”” Even this single identification has since been doubted. Mr. Cuming, who resided many years at Valparaiso, did not discover any West India specimens on that coast, and M. D’Orbigny makes the same observation. On the other hand M. Morch, of Copenhagen, says he has received Tellina opercu- lata and Mactra alata from the west coast and also from Brazil ; and M. Deshayes gives the following extraordinary ranges in his ‘‘ Catalogue of Veneride in the British Museum ”’:— Artemis angulosa, Philippines—Chili. Cytherea umbonella, Red Sea—Brazil. He maculata, W. Indies—Philippines, Sandwich. 3 circinata, W. Indies—West coast America, In these instances there is doubtless some mistake, either about the locality or the shell. As regards the last, Mr. Carrick Moore has shown that the error has arisen from confounding the Cytherea alternata of Broderip with C. circinata of Born. M. D’Orbigny collected 628 species on the coast of S. America, —180 from the eastern side, and 447 from the Pacific coast, be- sides the Siphonaria Lessonit which ranges from Valparaiso in Chili to Maldonado on the coast of Uruguay.+ These shells belong to 110 genera, of which 55 are common to both coasts, * British Association Report for 1863. ¢ The dispersion of this coast shell may perhaps have taken place at the time when the channel of the river S. Cruz formed a strait, joining the Atlantic and Pacific oceans, like that of Magellan. (Darwin, p. 181.) Mr. Couthouy makes 3 sp.— Siphonaria Lessonit, nearly smooth, Atlantic coast; S$. antarctica, ribbed, Pacific coast; and 3, lateralts, thin, oblique, Fuegia. 78 MANUAL OF THE MOLLUSCA. while 34 are peculiar to the Pacific, and 21 to the Atlantic sidé of S. America; an extraordinary amount of diversity, attribut- able partly to the different character of the two coasts—the eastern low, sandy or muddy; the western rocky, with deep water near the shore.* The comparison of the shells of Eastern and Western America is of considerable interest to geologists; for if 1t is true that any number of living species are common to the Pacific and Atlantic shores, it becomes probable that some portion of the Isthmus of Darien has been submerged since the Kocene Ter. tiary period. Any opening in this barrier would allow the Equatorial current to pass through into the Pacific—there would be no more Gulf stream—and the climate of Britain might, from this cause alone, become lke that of Newfoundland at the present day. Although geological researches seem to show that not only the Isthmus of Darien, but even the Rocky Mountains, were sufficiently submerged during the Miocene Epoch to allow of the free intermingling of the waters of the Atlantic and Pacific, yet the special temperate molluscan fauna of H. and W. America are very dissimilar. There are no grounds for believing a single species to be identical. There are, hovever, a large number of species (upwards of 50) living on both sides of the northern por- tion of the continent, and the majority of these exist in the British seas. XII. CALIFORNIAN PROVINCE. The shells of Oregon and California have been collected and described by Mr. Hinds,+ Mr. Nuttall,t Mr. Couthouy, natu- ralist of the American Exploring Expedition ;§ Mr. Cooper, Dr. Gould, Mr. Binney,|| Dr. Kennerley, Colonel Jewitt, and others. 4 Shells common to U. California and Sitka. (Maiddendorff.) Littorina modesta. Trochus ater. Trochus euryomphalus, + aspera. »» meestus. Petricola cylindracea, Fissurella violacea. » Fokkesii. Lutraria Maxima, + aspera. * Voyage dans l’ Amérique Ménidionale. 1847, t. v. p. v. t Voyage of H.M.S. Sulphur ; Zoology by R. B. Hinds, 4to. 1844. t Described by T. A. Conrad. Journ. Acad. N. 8. Philadelphia, 1854. § Gould in Bost. Nat. Hist. Soc. Proceedings, 1846; and U.S. Exploring Exped. (Commander Wilkes), vol. xii. Mollusca, with Atlas. 4to. Philad. 1852. ) Explorations for a railroad route from the Mississippi to the Pacific Ocean. 1856. { P. P. Carpenter on Mollusca of West Coast of North America. British Association Report for 1863, PANAMIC PROVINCE. 79 Scarcely any species are common to this province (extending from Puget Sound to the peninsula) and the Bay of California, which belongs to the Panamic province. The most important genera are Chiton, 18 species; Acmsea, 11 species; Fissurella, 6 species; Haliotis, 6 species; Trochus, 15 species; Purpura, 9 species. The following list probably contains some shells which should be referred to the Panamic province. Fusus Oregonensis. Chiton serobiculatus, &e. Saxidomus giganteus. Murex Nuttalli. Cleodora exacuta. Venerupis cordievi. Monoceros unicarinatus. Petricola mirabilis, A punctatus. Waldheimia Californica. Mactra, 2. Donax, I. Cancellaria urceolata. Discina Evausii. Tellina Bodegensis. Trivia Californica. —_—— » secta, &c. Natica herculea. Anoimia pernoides. Semele decisa. » Lewisii. Placunomia cepa. Cumingia Californica. Calyptrea fastigiata. Hinnites giganteus. Sanguinolaria Nuttalli. Crepidula exuviata. Perna, 1. Pinna, 2. Lutraria Nuttalli. “= navicelloides. Mytilus, 1. Pecten, 2. Platyodon cancellatus. = solida, &c. Mytilimeria Nuttalli. Amphichena Kindermanni. Imperator Buschii. Modiola capax. Lyonsia, 1. Thracia, 1. Haliotis Cracherodii. Chama lobata. Pandora, 1. Saxicava, 2. » iulgens. Cardita ventricosa. Cyathodonta undulata. » corrugata. Cardium, 4. Sphenia Californica. Fissurella crenulata. Lucina, 3. Periploma argentaria. a cucullata. Chironia Laperousii. Solecurtus subteres. Puncturella, 2 sp. Solecardia eburnea. Machaera lucida. Dentalium poliium. Venus Culiforniensis. “ maxima. Patella, 15 sp. » callosa. Mya truncata. Acmea scabra, ~ Artemis ponderosa. Panopea generosa, » pintadina. Saxidomus Petiti. Pholas Californica. Chiton Mertensii. + Nuttalli. » concamerata. XIII. PANAMIC PROVINCE. The Western coast of America, from the Gulf of California to Payta in Peru, forms one of the largest and most distinct pro- vinces. The shells of Mazatlan and the Gulf have been imper- fectly catalogued by Menke. The Mazatlan mollusks have been examined by Mr. P. P. Carpenter, who enumerates 654 species. ‘The total number of marine shells known belonging to this province is 1,341. Amongst these are included 27 Chitonidsee, 13 Acmeeidee, 18 Tissurellidee, 64 Trochoidse, 28 Calyptreeidee, 69 Pyramidellide, 59 Buccinide, and 90 Muri- cide. The gulf of California, together with the adjacent coast as far as Mazatlan and St. Blas, has yielded 768 shelis (502 uni- valves and 265 bivalves), of which 439 also occur in the Gulf of Panama, while 117 extend into S. America; 635 species are known from the Gulf of Panama; of these, 266 are peculiar to 80 MANUAL OF THE MOLLUSGA. the district, and 163 also occur in §. Ameriea. The fauna of the Panama province is remarkably distinct from the other W. American prcevinces, and especially the Caribbean. At one time it was thought that it did not possess a single species identical with any occurring in the West Indies or the east side of America. Dr. P. Carpenter, however, has shown that 35 marine shells (15 univalves and 20 bivalves) occur on both sides of the Isthmus of Darien, and this number has been lately increased. A few of the species even extend as far as W. Africa accord- ing to Dr. Carpenter; he mentions 15, and among them the following :—Crepidula unguiformis, C. aculeata, Hipponyx anti- quatus, Dankivia varians, Natica maroccana, Marginella cerules- cens, Nitidella guttata, Purpura pansa. Five species are common to Mazatlan and the British coasts, viz., Kellia suborbicularis, Lasea rubra, Sauxicava arctica, Cytherea Dione, Hydrobia ulvee. Still more remarkable is the absence of resemblance between the faunas of Panama and those of the Indo-Pacific area, there being only seven forms common to the two. Thus, Cytherea petichialis occurs in Japan; Nassa acuta, in Australia; and Oliva Duclosii, Natica maroccana, Nitidella cribaria, Hipponyx barbatus, H. Grayanus, are scattered over the Pacific ocean. The river-openings of this coast are bordered by mangroves, amongst which are found Potamides, Arcas, Cyrenas, Potamo- myas, Auriculas, and Purpuras, whilst Zittorince climb the trees and are found upen their leaves. The ordinary tide at Panama amounts to 16 or 20 feet, the extreme to 28 feet, so that once a fortnight a lower zone of beach may be examined and other shells collected. The beach is of fine sand, with reefs of rocks in the bay. Gallapagos Islands.—Out of 111 sea-shells collected here by Mr. Cuming, 43 are unknown elsewhere; 25 occurin Mazatlan, 22 in Central America, 38 in Panama, but only 11 in South America. Littoral shells common to Panama and the Gallapagos (C.B,. Adams.) Cyprea rubescens. Columbella nigricans. Turbinella cerata. Mitra tristis. Ricinula reeviana. Pleurotoma eccentrica. Planaxis planicostatus. Cassis coearctata. Hipponyx radiata. Purpura carolinensis. Oniscia tuberculosa. Fisstrella macrotrema. Columbella atramentaria. Conus brunneus, cP nigro-punctata. a bicanalifera, at) te Siphonaria gigas. ‘ heemas.oma. Strombus granulatns, PERUVIAN PROVINCE. 81 Panama shells. Strombus gracilior. Columbella strombiformis. Pecten magnificus. Murex erythrostomus. Marginella curta. Arca lithodomus, &c. s regius. Cypreea nigro-punctata. Pectunculus tessellatus, &o. » imperialis. Trivia, Nucula exigua. ayn STHOIK: Pyrula ventricosa. Leda, 5 sp. »» _ brassica. Natica glauca. Cardium senticosum. »» Monoceros, &c. Pileopsis hungaricoides. “ maculosum. Rapana muricata. Crucibulum auriculatum, &c. Cardita laticosta. » Kiosquiformis, Trochita mamillaris. Gouldia Pacifica. Myristica patula. Crepidula arcuata, &c. Cytherea, mary sp. Ricinula clathrata. Littorina pulchra. Venus gnidia. Purpura, many sp. Turritella Californica. » histrionica. Monoceros, many sp. Truncatella, 2 sp. Artemis Dunkeri. + brevidentatus. Ccecum, § sp. Trigona crassatelloides. Ae cingulatus. Imperator unguis, &c. Cyclina subquadrata. Clavella? distorta. Trochus pellis serpentis. Venernpis foliacea, Oliva porphyria. Vitrinella, 12 sp. Petricola Californica, &e. y» splendidula, &c. Nerita ornata. Tellina Burneti. Northia pristis. Patella maxima. Cumingia coarctata. Harpa crenata. — Semele, 7 sp. Malea ringeng. Discina strigata. Saxicava purpurascens. Mitra Inca, &c. » Cumingii. Gastrochena. Terebra luctuosa, &c. Lingula semen. Solecurtus lucidus. Conus regularis, &c. » albida. Lyonsia brevifrons. Pleurotoma, many sp. +» audebardi. Pandora arcuata, &c. Cancellaria goniostoma. Saeed Pholas melanura, &c. o cassidiformis. Placunomia foliacea. Parapholas. *A chrysostoma. Ostrea zequatorialis. Jouannetia pectinata. Columbella, many sp. Spondylus princeps. XIV. PERUVIAN PROVINCE. The coast of Peruand Chili, from Callao to Valparaiso, affords a large and characteristic assemblage of shells, of which only a small part have been catalogued, although the district has been well explored, especially by D’Orbigny, Cuming, and Philippi. M. D’Orbigny collected 160 species, one-half of which are common to Peru and Chili, whilst only one species (Siphonaria Lessonii) found at Callao was also met with at Payta, a little beyond the boundary of the region. Mr. Cuming obtained 222 species on the coast of Peru, and 172 in Chili. Hupé has described 201 species in Gay’s work on Chili. The island of Juan Fernandez is included within this province. Only a few of the Peruvian mollusks can be here enumerated. Onychoteuthis peraptoptera. Diphyllidia Cuvieri. Chiton, many sp. — Posterobranchea. Patella scurra. ZEolis Inca. Aplysia Inca. Acmea scutum. Dovis Peruviana. Tornatella venusta. Crucibulum lignarium. ’ E3 82 Trochita radians. Crepidula dilatata. Fissurella, many sp. Liotia Cobijensis. Gadinia Peruviana. Littorina Peruviana. na araucana. Rissoina Inca. Cancellaria buccinoides. Sigaretus cymba. Fusus Fontainei. Murex horridus. Ranella ventricosa. Triton scaber. Nassa dentifera. Columbella sordida. MANUAL OF THER MOLLUSCA. Oliva Peruviana. Rapana labiosa. Mouoceros giganteus. 5 crassilabris. a acuminatus. Purpura chocolata. Concholepas. Mitra maura. Terebratella Fontainei. Fs Chilensis. Discina lamellosa. » levis. Pholas subtruncata, &c. Lyonsia cuneata. Solen gladiolus. Solecurtus Dombeyi. Mactra Byronensis. Mesodesina Chilensis, Cumingia lamellosa. Semele rosea, &c. Petricola, many sp. Saxidomus opacus, &c. Cyclina Kroyeri. Venus thaca. Crassatella gibbosa. Nucula, many sp. Leda, many sp. Solenella Norrisii. Lithodomus Peruvianus. Saxicava solida. XV. MAGELLANIC PROVINCE. This region includes the coasts of Tierra del Fuego, the Falk- land Islands (Malvinas), and the mainland of South America, from P. Melo, on the east coast, to Concepcion, on the west. It is described by M. D’Orbigny and Mr. Darwin (Journal, p. 177 et seq.). Philippi also has given attention to it; he assigns 88 species to the district near the Straits of Magellan. Only 16 species are known from the Malvinas, and 11 of these have not been met with elsewhere. The southern and western coasts are amongst the wildest and stormiest in the world; glaciers in many places descend into the sea, and the passage round Cape Horn has often to be made amidst icebergs floating from the south polar continent. The greatest tides in the straits amount to 50 feet. ‘‘In T. del Fuego the giant sea-weed (Aacrocystis pyrifera) grows on every rock from low-water mark to 45 fathoms, both on the outer coast and within the channels; it not only reaches up to the surface, but spreads over many fathoms and shelters multitudes of marine animals, including beautiful compound Ascidians, various patelliform shells, Trochi, naked mollusca, cuttle-fish, and attached bivalves. The rocks, at low water, also abound with shell-fish which are very dif- ferent in their character from those of corresponding northern latitudes, and even when the genera are identical the species are of much larger size and more vigorous growth.’’* Shells of the Magellanic Province (* Falkland Islands). Buccinum antarcticum, Monoceros imbricatus. Trophon Magellanicus. 5 Donovani? ” glabratus. Voluta Magellanica. Bullia cochlidium. Js calcar. » ancilla. * Shell-fish are here the chief support of the natives as well as of the wild animals. At Low’s harbour a sea-otter was killed in the act of carrying to its hol a large Volute, and in T. del Fuego one was seen eating a cuttle-fish—Darwin. PATAGONIAN PROVINCE. 83 - Natica limbata. *Patella barbara. Pecten corneuse Lamellaria antarctica. 5 -zeberina: Mytilus Magellanicus, Littorina caliginosa. Siphonaria lateralis. *Modiolarca trapezina. Chemnitzia Americana. Chiton setiger. Leda sulculata. *Scalaria brevis. Doris luteola. *Cardita Thouarsii. ¥Trochita pileolus. ZEolis Patagonica. *Astarte longirostris. Crepidula Patagonica. *Spongiobranchea. *Venus exalbida. Trochus Patagonicus. Spiralis? cucullata, 66° S. *Cyamium antarcticum. *Margarita Malvine. Mactra edulis. *Scissurella conica. Terebratella crenulata. *Lyonsia Malvinensis. *Fissureila radiosa. * ,, Magellanica,many Pandora cistula. Puncturella cenica. varieties. Saxicava antarctica. Nacella cymbularia. Waldheimia dilatata. Octopus megalocyathus. *Patella deaurata. Pecten Patagonicus. XVI. PATAGONIAN PROVINCE. From §. Catharina, south of the Tropic, to P. Melo. This coast-line has shifted considerably since the era of its present fauna. M. D’Orbigny and Mr. Darwin observed banks of recent shells, especially Potamomya labiata, in the valley of La Plata and the Pampas around Bahia Blanca. Mr. Cuming also met with Voluta Brasiliana, and other living shells, in banks 650 miles inland. Of 79 shells obtained by M. D’Orbigny on the coast of N. Patagonia, 51 were peculiar, 1 common to the Falk- land Ids., and 27 to Maldonado and Brazil. At Maldonada 37 species were found, 8 being special. 10 common to N. Patagonia, 2 to Rio, and 17 to Brazil. Of the latter § range as far as the Antilles; viz. : Crepidula aculeata. Mactra fragilis. Modiola viator. » _protea. Venus flexuosa.* Plicatula Barbadensis. Pholas costata. Lucina semi-reticulata, At Bahia Blanca, in lat. 39° S., the most abundant shells observed by Mr. Darwin (p. 243) were Oliva auricularia. liva tehuelchana. Yoluta anculata, » puelchana, Voluta Brasiliana. Terebra Patagonica. M. D’Orbigny’s list also includes the following genera and species :— Octopus tehuelchus. ZEolis. Leda. Columbella sertularium. Paludestrina, Cytherea. Bullia globulosa, Scealaria. Petricola. Pleurotoma Patagonica. Natica. Corbula. Fissurellidea megatrema. Chiton, Pinna. Panopea abbreviata. Solen. Mytilus, Periploma compressa. Lutraria. Lithodomus, Lyonsia Patagonica. Donacilla. Pecten. Sclecurtus Platensis. Nucula. Ostrea. * The variety of Venus fleruosa found at Rio can be distinguished from the West ‘Andian shell, which is the Venus punctifera of Gray. 84 MANUAL OF THE MOLLUSCA. XVII. CARIBBEAN PROVINCE. The Gulf of Mexico, ite West Indian Islands, and the eastern coast of South America, as far as Rio, form the fourth great tropical region of marine life. mated by Prof. C. B. Adams at not iess than 1500 species. The number of shells is esti- Of these 500 are described by M. D’Orbigny in Ramon de la Sagra’s History of Cuba, and a small number of the Brazilian species in the same author’s Travels in South America. A list of the Barbadoes shells has been given by Sir R. Schomburgk. The coasts of the Antilles, Bermuda, and Brazil, are fringed with coral reefs, and there are considerable banks of gulf-weed at some distance from the coast of the Antilles. West India Shells. Argonauta. Ommastrephes. Cleodora. Octopus. Sepioteuthis. Creseis. Philonexis. Sepia. Cuvieria, Loligo. Spirula. Atlanta. Cranchia. Hyalea. Oxygryus. Onychoteuthis. Strombus gigas. » pugilis. Murex calcitrapa. Pisania articulata. » turbinella. Triton pilearis. 3» cutaceus. Fusus morio. Fasciolaria tulipa. Lagena ocellata. Cancellaria reticulata. Fulgur aruanum. Terebra acicularis. Myristica melongena. Purpura patula. deltoidea. Oniscia oniscus. Cassis tuberosa. flammea. » Madagascariensis, Coluy beila mercatoria. et nitida, &e. Volv .a vespertilio. 5 musica. f siva brasiliensis. » angulata. » jaspidea. » oryza, &c. Ancillaria glabrata. Conus varius, &c. Clavatula zebra. Marginella. Erato Maugerie. Cypreea mus. exantheima. 9» spurca, &c. Trivia pediculus. Cvulum gibbosum. Natica caurena. Pyramidella dolabrata. Planaxis nucleus. Littorina zic-zac. flava. s% lineolata. Tectaria murizata, Modulus lenticularis. Fossarus. Truncatella caribbea. Torinia cylindracea. Turritella exoleta. 95 imbricata. Trochus pica. Imperator tuber. + calcar. Fissurella Listeri. nodosa. Barbadensis. ” ” 3? 9 Nerita. Neritina. Hemitoma 8 radiata, Cheletropis. Tanthina. Glaucus. Notarchus Plei. Aplysia. Hipponyx mitrula. Pileopsis militaris. Calyptrea equestris. Crepidula aculeata. Patella leucopleura. Chiton squamosus. Hydatina physis, Bouchardia tulipa. Discina antillarum. Placunomia foliata. Plicatula cristata. Lima scabra. Mytilus exustus. Lithodomus dactylus. Arca Americana. Yoldia tellinoides, Chama arcinella, »» macrophylla. Cardium levigatum. Lucina tigrina. Pennsylvanica. s» dJamaicensis, Corbis fimbriata. Coralliophaga. Crassatella. Gouldia parva. Venus paphia. dysera. ” TRANS-ATLANTIC PROVINCE. 85 Venus crenulata, Artemis concentrica. Strigilla carnaria. » cancellata, ES lucinalis, Sernele reticulata. s» violacea. Cyclina saccata. » Vvariegata. Cytherea dione. Trigona mactroides. Cuminyia. ss circinata, Petricola lapicida. Iphigenia Brasiliensis. “: maculata. Capsula coccinea. Lutraria tineata, “< gigantea. Tellina Braziliana. Periploma inzquivaivis. = flexuosa. » bimaculata. Pholadomya candida. XVIII. TRANS-ATLANTIC PROVINCE. The Atlantic coast of the United States was supposed by Prof. E. Forbes to consist of two provinces: (1) the Virginian, from C. Cod to C. Hatteras, and (2) the Carolinian, extending to Florida; but no data were supplied for such a division. The total num- ber of mollusca is only 230, and 60 of these range farther north, 15 being moreover common to Europe. These two regions are sometimes treated of together as the Pennsylvanian province. Dr. Gould describes 110 shells from the coast of Massachusetts south of Cape Cod, of which 50 are not found to the northward, but form the commencement of the proper American type. The shells of New York and the southern Atlantic States are de- scribed by De Kay, in the State Natural History of New York; this list supplies 120 additional species, of which at least a few are stragelers from the Caribbean province; e.g. Chama arcinella, Iphigenia laevigata, Capsula deflorata.* M. Massachusetts. Y. New York. SC. South Carolina. F. Florida, Conus mus. F, Cerithium ferrugineum., F. Fusus cinereus. M. SC. oe 4sp. M. Nassa obsoleta. M. F, (Mex.) Triforis nigro-cinctus. M. », trivittata. M. SC. Odostomia, 6 sp. M. Y » vibex. M. F. (Mexico). Turritella interrupta. M. Y. Purpura Floridana. (Mex.) “ concava. SC. Terebra dislocata. Y. SC. (Vermetus lumbricalis, M. ?) Pyrula? papyracea. F. Calyptrea striata. Y. Fulgur carica. M. SC. Crepidula convexa. M. Y. » canaliculatum. M. SC. » fornicata, M. F. (Mex). Oliva literata. SC. Littorina irrorata. Y. Marginella carnea, F, Fissurella alternata. (Say) ? Fasciolaria distans. SC. (Mex.) Chiton apiculatus. M. SC, Columbella avara. M. Y. Tornatella puncto-striata, M. Y. Ranella caudata. M. Y. Bulla insculpta, M. Y. Natica duplicata. Y. SC. — Sigaretus perspectivus. Q. SC, Ostrea equestris. SC. F. Scalaria lineata. M. SC, Pecten irradians (sca/lop). = multistriata. M. Y. Avicula Atlantica, F. ” turbinata. NC. Mytilus leucophantus. SC. * The sea-shells, of the United States have also been collected and described by Say, Le Sueur, Conrad, and Couthouy. 86 MANUAL OF THE MOLLUSCA. Modiola Carolinensis. Mactra similis. SC. M. » plicatula. M. Y. 5, solidissima. M. Y¥. Pinna muricata. SC. » Jateralis, M. Y. Arca ponderosa. SC. Lutraria lineata, F. » pexata. M.F. 3 canaliculata. Y. FB » inconyrua. SC. Mesodesma arctata. M. Y. », transversa. M. Y. Tellina tenta. M.SC. Solemyavelum. M. Y. 8 /sp: oC sen. 6 borealis. M. Semele equalis. SC. Cardium ventricosum. SC, Cumingiatellinoides. M, on Mortoni. M. Y. Donax fossar. Y. Lucina contracta. Y. 5). Vamabilis.. Gai Astarte Mortoni. Y. Solecurtus fragilis. M. SC. » bilunulata. F. =P caribbeeus. M. F. Carditaincrassata. F. Corbula contracta, M. F. Venus mercenaria. M. SC. Periploma Leana. M. Y. » Mortoni. SC. F. 9 papyracea. M. Y. » gemma, M.Y. Lyonsia hyalina. Y. Artemis discus. SC. Pandora trilineata. M. F. Petricola dactylus. M. SC. Pholas costata. SC. F. i. pholadiformis. Y. yy +semicostata. SC, LAND REGIONS. Distribution of Land and Fresh-water Shells. The boundaries of the Natural-history land-regions are more distinctly marked, and have been more fully investigated, than their counterparts in the sea. Almost every large island has its own fauna and flora; almost every river system its peculiar fresh-water fish and shells; and mountain-chains like the Andes appear to present impassable barriers to the ‘‘ nations” of animals and plants of either side. Exceptions, however, occur which show that beyond this first generalisation there exists a higher law. The British Channel is not a barrier between two provinces, nor is the Mediterranean ; and the desert of Sahara separates only two portions of the same zoological region. In these and other similar instances the ‘‘ barrier”’ is of later date than the surrounding fauna and flora. It has been often remarked that the northern part of the map of the world presents the appearance of vastly-extended, conti- nental plains, much of which is, geologically speaking, new land. In the southern hemisphere the continents taper off into promontories and peninsulas, or have long since broken up into islands. Connected with this is the remarkable fact that only around the shores of the Arctic Sea are the same animals and plants found through every meridian ; aud that in passing south- ward, along the three principal lines of land, specific identities LAND REGIONS. 87 give way to mere identity of genera; these are replaced by family resemblances, and at last even the families of animals and plants become in great measure distinct, not only on the great conti- nents, but on the islands, till every little rock in the ocean has its peculiar inhabitants—the survivors, seemingly, of tribes which the sea has swallowed up. (Waterhouse.) The two largest genera, or principal types of the land and fresh-water shells, Helix and Unio, have an almost universal range, but admit of many geographical subdivisions.* Amongst the land-snails are several species to which a nearly world-wide range has been assigned, sometimes erroneously, as when Helix cicatricosa is attributed to Senegal and China, or Helix similaris Fér. to Brazil and India; and often correctly, but only because they have been carried to distant localities by human agency. Land-snails are in fayour with Portuguese sailors, as ‘‘ live sea stock ;”’ and they have naturalised the common garden-snail of Europe (Helix aspersa) in Algeria, the Azores, and Brazil; and Helix luctea at Teneriffe and Mte. Video. >; Irkutsk. + albus, Bernaul, ,, Limnza Gebleri, M. Bernaul. :; contortus, 4, ae auricularia, Nertschinsk. + vortex, + 4 ovata, Bernaul. on leucostoma, 4, a Kamtschatica, Mid. .3 nitidus, Irkutsk. » peregra, Bernaul, Beresov. Bithynia tentaculata, Bernal, ——s LUSITANIAN REGION. 91 Bithyvia Kickxii, R. Ami, Altai. Anodon anatinus, Tunguska. Valvata cristata, var. Sibirica, Bernaul, > cellensis var. Beringiana, Kamt- Beresov; Kamtschutka. schatka, s piscinalis, R. Ami. Cyclas calyculata, Bernaul, R. Lena, R. Unio complanains Kamtschatka,. Ami, 5. Kamts, y Dahusicus, Mid. Schilka, Pisidium fontinale, Beresov. » Mongolicus, M. Gorbitza, Dauria. + obliquum, Bernaul, Tomsk. Anodon herculeus, M, Scharanai. 2. LUSITANIAN REGION. The countries bordering the Mediterranean, with Switzerland, Austria, and Hungary, the Crimea (Yaurida), and Caucasus, form a great province (or rather cluster of provinces) to whick Professor E. Forbes appled the term Lusitanian. The Canaries, Azores, and Madeira are outlying fragments of the same region.* In Southern Europe about 600 land-snails are found, of which above 100 are also spread over the Germanic region and Siberia; and 20 or 30 are common to Northern Africa. Besides these 60 others are found in Algeria and Egypt, 100 in Asia Minor and Syria, and 135 in the Atlantic Islands, making a total of nearly 900 species of Helicidee.+ _ Of the 12 species of Zonites (proper) 10 are pecular to Lusitania. The species of Bulimus, Achatina, and Pupa are small and minute, belonging to the sub-genera Bulimulus, Cionella, Zua, Azeca, Vertigo, &c.; 4 (of which 2 are Algerian) have been referred to Glandina. In this region are also found 22 species of Cyclostomide and 44 Limacide :— RELIG yoveccessosssse 2100002 WitPiniscAcecescoseectes il Cryptella: + cccccscscors eo Lo ae 80 Daudebardia........... iyo Cyclostontac.c.s.-ec 5 SC GE ae 8 Helicolimax .......... 3 Craspedopoma ......... 3 STESALINIR Soca vce ssaaces 25 Tae iiev.scesseeeres | 20 POMAtASHs eecesesoaees 10 Tornatellina .......... cae ve ATION: Soci seccces Sacks ote et! AGCiCUIAL piscccccescteres 4 PMNs ceo cecacessceute 4 Phosphorax ............ 1 — iia cies 120 Mestacella..s.-ccn<2-0s 2 Carychium .......... eee OLAS a a 247 Parmacella. 3.:..5.0e son 4 — — PATIOWM eps scsercnacases sess 1 MS ITATICE Rs «stteeencetes tee 1 Paludina ..e..0sn0- si — IPL VSaiacusasevecere ecsese 4 Nerilinanccocpesees peek: WVALUTIM Bertesaivcsweaceevescs 4 PHYSOPSIS ..s-5-scsvecene 1 —-- FLOUR Veeauiee assesses ehves 35 ANGYLUS ecacesvcsssvecens 1 Corbicula, <-.cscssesss fou SCCM CA an sscscessiers o (4 IPIQNOEDIS | cokessvocsecoss 3 Cy clas’ iccsedeseesereeen oe SES ITIITARTIS saw canoeiisesssse 13 — Pisiditima Vw wsceeeeesnes 1 PUPA cccsessscsseeseverse G Waginulas:......cscacc 9) migne eee Br IACHALING) \scctesienssnces 7 Oncidiumrencsascasesrss eel TTidING . sivensessescseeneaan: Cyclostoma crerercoeree 6 AUTICUIA .iseeere sostese 6 5. YEMEN—MADAGASCAR. The 8. W. Highlands of Arabia (Yemen) form a distinct Botanical province isolated by rainless deserts to the north. The land snails consist of a few species of Helix and Bulimus, Cyclostoma lithidion, and 3 species of the section Otopoma, a group also found in Madagascar. Two species are common to the island of Socotra (No. 30), which also has a species (of Pupa) common to Madagascar. Bulimus guillaini, Cyclostoma gratum, modestum and Souleyeti are found on the island of Abd-el-Gouri. Very few land shells have been collected on the mainland of Eastern Africa, although it is a rainy region, and well wooded in the southern part; 5 species only are recorded from Moga- doxa and Ibu, belonging to the genera Helix, Bulimulus, Acha- tina, Pupa, and Otepoma. Onthe Island of Zanzibar are found Achatina Rodatzi and allisa, Cyclostoma Creplini and Zangue- barica ; Pupa cerea is common to Zanzibar and Madagascar. Madagascar itself is rich in land shells; Dr. Pfeiffer enume- rates—Helix 28 sp., Bulimus 6, Succinea 14, Pupa 1, Achatina 4 (one of which, eximia, is allied to A. Columna, of W. Africa), and 82 Cyclostomide, chiefly of the section with spiral ridges (Tropidophora), 3 of the division Otopoma. Cyclostoma carini- Jerum and Cuvieri are found on the Island of Nosse Be; Helix guillainti on 8. MariaI. Amongst the fresh-water shells are Melania amarula, Melanatria fluminea, and Neritina corona. The land shells of the Mascwrene Islands are nearly all pecu- liar; we are indebted to Mr. W. H. Benson for most of the information existing in respect to them. Comoro Islands. Helix russeola and Achatina simpularia are found in Mayotte ; Cyclostoma pyrostoma in Mayotte and Madagascar. INDIAN REGION. 99 Seychelles (No. 31 of Map). Parmacella Dussumieri. Bulimus ornatus. elix unidentata. 7 fulvicans. 5, _studeri. Cyclostoma insulare. » Souleyeti. = pulchrum, », Tranquebarica. Cyclotus conoideus. Streptaxis Souleyeti. Mauritius (32). Parmacella perlucida. Helix Barclayi. Pupa Largillierti. 5 Rangii. » odontina. Cyclostoma Barclayi. = mauritii, Vitrina angularis. ee Michaudi, Helix philyrina. Tornatellina cernica, op carinatum., yy inversicolor. Gibbus Antoni. 53 undulatum. 33 stylodon. »» Lyonneti. ae insulare ? », mauritiana. Succinea sp. Cyclotus conoideus ? »» mauritianella. Bulimus clavulinus. Otopoma Listeri. »» rawsoni. oh Mauritianus, “ hemastoma. 9» semicerina. Pupa pagoda. Realia rubens. » mucronata. » fusus. »» aurantiaca. » Nnitella, » sulcata, >» multilirata. ae ruta: », clavulata. » €Xpansilabris. » Similaris. 3, modiolus, » globosa. 3 suffulta. »» funicula. Megalomastoma croceum, » albidens. 3» Versipolis. Two large species of Achatina (fulica and panthera) abounding in the coffee plantations, are believed to have been introduced. The annual fall of rain in Mauritius is 35°25 inches, Bourbon (No. 33). Helix celatura. ' Helix tortula. » detecta. .y, Brandiana. 33 elibata ? Pupa Largillierti—Mauritius. Rodriguez. Cyclostoma articulatum, Madagascar ? Streptaxis—pyriformis, No. 34. Kerguelen’s Land. WHelix Hookeri was collected at this island when visited by the Antarctic Expedition. 6. INDIAN REGION. Proceeding eastward, in Asia, the species of Achatina, Pupa, Clausilia, Physa, Limax, and Cyclostoma rapidly diminish or quite disappear. Helices of the section Nanina become plenti- ful, amounting to 150 species, and Bulimulus and Cyclophorus attain their maximum. Leptopoma, and Pupina are peculiar to the Asiatic Islands. Our catalogue of Indian land shells must be very imperfect, including only about 180 Helicide and 50 Cyclostomide. A very E2 100 MANUAL OF THE MOLLUSCA, few of the Indian species are common to China and the Asiatic Islands, or even to Ceylon. ‘The shells of northern India resemble those of the Lusitanian region; in the south they approximate more to the large and vividly coloured species of _ the AsiaticIslands. In the Himalaya land shells are numerous, and ascend as high as the region of Junipers and Rhododen- drons, 4,000—10,000 feet above the sea. PVCU Newecdeuececaeersesees 83 Up aieererscssecsacecees cs 7 Cyclophorus .......0ce0. 26 TeV EMTEY ascegoccrind adc 46 ClgUSiIa: sess cssessceres | LeptopoOMma ssesecsecree 2 Ariophanta ........-4.. 8 WAlIDIN A Nasitsasraaliestssse= 9 \Plerocyclus ies. 10 Streptaxs ...0.0cesceees 3 DUCCINGAN scseccestecsars 7 Cyclotus’ Wevesesssseanat 3 ESTMIINIATIS cedenameneaesas cab 45 Parmacella ........0000 2 Megalomastoma ...... 4 ACHATING Wircsssuvesssces 16 Cyclostoma. ........... See Diplommatina ......... 3 Parmacella and Vaginulus are found in India, and the typical fresh-water species of Oncidiwm. Ordinary forms of Limnea and Planorbis are abundant, and there is one species of Ancylus. Physa occurs only in a fossil state, or is represented by the singular Camptoceras of Benson. Hypostoma Boystt, Auricula Jude, and Polydonta scarabeus are also Indian forms. The gill-breathing fresh-water shells of India are very numerous, especially the Melanias and Melanatrias, and species of Pirena, Paludomus, Hemimitra (retusa), Ampullaria, Paludina, Bithynia, Nematura (deltee), Assiminea (fasciata), Neritina (par- ticularly crepidularia and Smithi) and Navicella (tessellata). The brackish-water species of Cerithidium, Terebralia, and Pyrazus are mostly common to India and North Australia. The fresh-water bivalves are a few ordinary forms of ‘Unio, 8 species of Cyrena, a Corbicula (of which 6 species have been made), Cyclas Indica, Arca scaphula, Glaucomya cerea, and Nova- culina gangetica. Ceylon. The land-shells of Ceylon haye been investigated by Mr. Benson; they most resemble those of the Neilgherry hills, but are nearly all specifically distinct, and even some of the genera are peculiar. It seems entitled to rank as a province. Helix Waltoni and Skinneri, are examples of the most charac- teristic form of Helices; the Vitrini-form type (Nanina) is also common. JH. hcemastoma, one of the most conspicuous species, found on trees at P. Galle, is common to the Nicobar Islands. The Achatinas beiong to a distinct section (Leptinaria, Beck), also represented on the Continent. Some of the Bulimi approach the Philippine forms. HALON cosssccscscssncedsss 46 SUCCINGS, avixaccdasessss 1 Pterocyclus .......... as MN AIDINID ‘Sowisccvccescvevess 9 Pupa Go et uleh ioe age: AUlOPOMA ......00c0000. 4 WAUINGiscs evsscsscsertes AO ACHALNG. cjecsscessersee AO Leptopoma ........ ccd DULEPLANIS vsescovscsesece 2 Cyclophorus ....0. cree L2 CataulUs .ec.sscccsere LO Bulimus., Begeroceraresone 13 i "Po = PHILIPPINE ISLANDS. 10] The fresh-water shells belong to the genera Limneea, Physa, 2 species (not found on the Continent); Planorbis, Melania, Tanalia 10 (peculiar), Paludomus, Bithynia, Ampullaria, Neri tina, Navicella, Unio, and Cyrena. At the Nicobar Islands are found—Cataulus tortuosus, Heli- cina Nicobarica and Pupina Nicobarica. Helix castanea is from Sumatra. (Beck.) 7. CHINA AND JAPAN. The few lard-snails known from China are of Indian and Lusitanian types; yviz.—Helx 20, Nanina 10, Streptaxis 1, (Cochin-China), Bulimus 5, Achatina 2, Pupa 1, Clausilia 11, Succinea 1, Helicarion 6, Cyclophorus 1, Cyclotus 1, Otopoma 1. In the Island of Chusan Dr. Cantor discovered the genera Lampania and Incilaria. The most characteristic bivalves are Glaucomya Sinensis, and Symphynota plicata; 3 species (or varieties) of Cyrena and 9 Corbiculas are described by Deshayes, and a Planorbis by Dunker. In the Japanese and Loo-choo Islands only 9 species of Helix, 2 of Nanina, 2 of Clausilia, and 2 of Helicarion haye been hitherto obtained. 8. PHILIPPINE ISLANDS. The extraordinary richness of these islands has been developed mainly by the researches of Mr. Cuming. The Helicidcee (above 300) are inferior in number only to those of Lusitania and the Antilles, and yastly superior in size and beauty of colouring. The Cyclostomidee (55) are not much fewer than in India. Nearly all the species are confined to particular islands, and the repeti- tion of forms makes it probable that many of them are geogra- phical varieties. The climate is equable, with a temperature like that of South China (66°—84°), woods are prevalent and the rains heayy—all circumstances fayourable to the individual abundance of land-snails. PERCU iies vuceseceup soesses 160 COIN THe cececestacsese 1 C@yclotus! Sccscevsrsee eG UCEIEUH Sh cogs scces'voseee vee 40 DWIRIRINIG\ <.sucksccseuers 12 HICH GING: \oesscces ss csves 13 PEE tess nsecescnp cases 15 CCHTINA, <.nscsesseucnce 1 The fluyiatile shells are species of Physa, Melania, Assiminea * The Feejees (Viti) are more nearly allied to the westward islands, such as the New Hebrides, than the Friendly Islands. Succinea and Partula, so plentiful at the latter, are not found at the Feejees. (Gould, U.S, Exploring Expedition). F3 106 MANUAL OF THE MOLLUSCA. (Taheitana) Neritina, and Navicella; the two last being often littoral, or even marine, in their habit. Low Coral Islands. The Atolls, or lagoon-islands, are less prolific: 2 Helices and 2 Partule are found at Oualan, in the Caroline Archipelago ; and from Chain Island (Annaa), the centre of commerce in the eastern Archipelago, haye been obtained—Helix 2 sp., Nanina 1, Partula 1, Tornatellina 1, Cyclophorus 1, and Melampus mucro- natus. Sandwich Islands. The land shells of these islands exceed 200, and are all, or nearly all, peculiar: there is one Zimaz ; and in the fresh waters are found Limnuwa volutatrix, Physa reticulata (Gould), Neritopsis ? Neritina Nuttalli and undata, and Unio contradens (Lea). In the I. Kaui, two species of Achatina haye been found: the Achatinellz are elongated (Leptachatina, G.) and the Helices planorboid and multispiral. In Molokai the Achatinelle are large and coloured. In Maui and Oahu the Helices are small and glabrous, or hispid, ribbed, and toothed. In Hawai, Suc- cineas prevail, and Achatinellae are rare. (Gould.) The large number of Achatinellae is partly due to this group haying been specially studied by Judge Cooper of America. MACHR Sores devescseccuisesst 20 A Chatina des.c%.eteoe 5 PUPS ssoscceatdcavesenssen 2 UNAMID Bones ecaceccesecces 5 Achatmella, ccceseese 204 Vitving, iscdesicadeaensee 2 SGUITIVUS: scaccvescssaceess 5 Tornatellina,..<..s. 6.4 3 SUCCINCGNns scncouccseacse 10 IPAEUTID ceccccaee! cocsacee 4 IBA CAncssccotccseaccisesse 1 Helicing © .cssccsceseasee 6 The Island of Guam, Ladrones, has 3 sp. of Partula, 2 of Achatinella, and 1 Omphalotropis. At the Marquesas haye been found 3 sp. of Nanina, 1 Partula, and 1 Helicina. NEW WORLD. 16. CANADIAN REGION. The country drained by the Great Lakes and the river St. Lawrence possesses very few peculiar shells, and these mostly of fresh-water genera. It is chiefly remarkable for the presence of a few European species, which strengthen the evidence before alluded to (p. 60) of a land-way across the north Atlantic haying remained till after the epoch of the existing animals and plants.* * For example, the common Heather ( Calluna vulgaris), one of the most abundant sociae plants of Europe, characteristic of the moorland zone, and seldom rising above ATLANTIC STATES. 107 Helix hortensis (imported), coast of New England and banks of St. Lawrence. » pulchella (smooth var. only), Boston, Ohio, Missouri. Helicella cellaria (glaphyra, Say ?), N. E. and middle States, » pura, nitida, and fulva? Zua lubrica, North West Territory. Succinea amphibia (= campestris, Say ?). Limax agrestis (= tunicatus, G.), Mass. ;, Havus, New York, introduced. Vitrina pellucida (= Americana ?) Limnea palustris (= elodes, Say ?). Arion hortensis, New York (Dekay.) _ truncatula (= desidiosa?). Aplexa hypnorum (= elongata, Say ?). Auricula deticulata, Mont., New York Harbour. Alasmodon margaritiferus (= arcuatus, Barnes). Anodon cygneus (= fluviatilis, Lea ?). The shells proper to Canada, or derived from the adjoining States, are only 6 sp. of Helix, 2 Succineas, and 1 Pupa; 8 sp. of Oyclas have been obtained from the region of Lake Superior. The following species occur in New England :— 1 TE 2-6: ofocaonenocueeeoe 13 12h ioe occectocococansecece 2 LOMIG oraceceenonocidondsoc 5 SUCCINED ....sccscecss0s 2 IPTANOTDISU cee. ssoes eee 11 Alasmodon ........000. 2 PUD eaisessscadsse said ates vi PaVIGINAD seensascecacees i ANOGOM: seccscecccsscceess 2 MATIC i accoscessece sce 7 Wicilwaltalcasessenceenesve 2 (ONES cooocooccsnenccoac 6 PATIGVLUS: dense sna cece sss 2 ATIFIGHIAY cececesesnvanos 1 PISIGIUME ecccescecoense Ez Carychium exiguum, Say, is found in Vermont, and Limneea (Acella) gracilis in Lake Champlain; Valvata tricarinata and Paludina decisa are characteristic forms. The genera Clausilia and Cyclostoma are entirely wanting in Canada and the Northern States. The Limacide are represented by Philomycus, of which there are 9 reputed species, ranging from Massachusetts to Kentucky and South Carolina. 17. ATLANTIC STATES. The parallel of 36° N. lat. forms the boundary-line of two botanical regions in the United States; but the evidence of the fresh-water shells, in which they are particularly rich, seems to fayour a division into two hydrographical provinces—the region of the Atlantic streams and the basin of the Mississippi. About 50 fresh-water Pulmonifera, 150 pectinibranchiata, and 250 bivalves, are reputed to be found in the States, and it is supposed that only a few species are common to both sides of the Alleghanies. Oyclas mirabilis, Pisidiwm Virginicwum, Cyrena 3,000 feet on the mountains of Scotland. (Watson.) According to Pallas it abounds on the western flanks of the Ural Mountains, but disappears on their eastern side, an is not found in Siberia. In the Pliocene period it appears to have spread itself north ward and westward to Iceland, Greenland, and Newfoundland, where it still grows, the only heath indigenous to the New World. (Humboldt.) 108 MANUAL OF THE MOLLUSCA. Carolinensis, and Unio complanatus and radiatus, are character- istic of the eastern rivers; Melania depygis is said to be the only member of that large genus found eastward of the Hudson River. Of the American land-snails, 29 sp. of Helix, 6 Suc- cineas, and 13 Pupas are enumerated from the Atlantic States. In Florida the propinquity of the West Indian fauna is strongly indicated by the occurrence of the great Glandina truncata, by species of Cylindrella, and a Helicina. A Cuban species of Chondropoma (C. dentatum) is also said to occur in Florida, and Ampullaria depressa in Florida and Georgia. The Pulmonifera of North America have been carefully exa- mined by Messrs. Binney,* Bland,+ and others. The following summary of North American Pulmonifera is given by Mr. Binney, The area is nearly co-extensiyve with our regions, Nos. 16 and 17. ATION oss sscecesesesseeess 2 BINNS cc ecoccecteses one 21 Melampus ......secseeees 11 WEWETUIG) Scvetaeasvcn cosas 3 ACHAHNGE Vecieceee seeds: 5 Cary chim) ..0.--coness 1 ENUOMYCUS S.ccecvesees 2 TIPE aes decesicce deve tsee st 12 imMNW...c,0s.cessseennes B4 SVAN eoeees essere gsosss> PVCU ON senece caer coante 4 PHYS8. -aucneeseomeoeenee 19 MUICCINGS) scecvesesnesees 18 Cylindrella ............ 4 PIanOrpis ..-cssseeseusan 21 Ap landing: Son. cccscoseese 6 Veronicella: ....c.c0000 1 ATICY1US: .cicreswsensenves 10 EV QUUKHT sas, Socsees osvbea se 131 There are also found in the fresh waters of this district Mela- niadee 380, Paludinide 58, Cycladide 44, Unionide 552. 18. AMERICAN REGION. The mass of American land and fresh-water shells are found in the central and southern States, the country drained by the Mississippi and its tributaries. The Helictde are not more re- markable for size and colour than those of northern Europe ; the most characteristic forms belong to the sub-genus Polygyra (or Tridopsis, Raf.), such as Helix tridentata, albolabris, hirsuta, and septemvolvis. The truly North American forms all belong to three genera, viz.—Helix 43, Succinea 8, Pupa 3 species. In the Southern States are also found 5 species of Bulimus, 3°Cylindrellas, 2 Glandinas, and 5 Helicinze, genera whose metropolis is in the Antilles or in tropical America. The fresh-water univalyes include aboye 100 species of Mela- niade belonging to the genera Ceriphasia, Melafusus, Anculotus, Melatoma, and Ammnicola, 15 Paludine, some keeled, and one * Tn several papers in Proc. Acad. Nat. Sci. Phil. 1°57, and subsequent years. + Remarks on the Classification of N. Am. Heliceg Annals of Lyceum of Nat, Hist,, _ New York. 1363. MEXICAN REGION. 109 muricated (P. magnifica); and species of Valvata, Limneea, Physa (15), Planorbis, and Ancylus (5). The fresh-water bivalves are also extremely numerous: the Unionide are unequalled for their ponderous solidity, the rich tinting of their interiors, and the variety of their external forms.” Gnathodon cuneatus, Cyrena floridana, 16 species of Cyclas, and Pisidium altile, belong to this region. 19. OREGON AND CALIFORNIA. The Fauna of the region beyond the Rocky Mountains is believed to be almost entirely distinct from that of the United States. Arion (foliolatus) and Zimax (Columbianus), genera not indigenous to eastern America, were found near Puget Sound. (Gould). We have no information respecting the land and fresh-water shells of Russian America, but from analogy we may expect to find a few there identical with those already mentioned as occurring in Siberia. t+ The shells of Oregon and California are principally known by the researches of Nuttall, Couthouy, and Binney. 18 05K crngesnosedenossee ee SHE TRIN SE ogroodoacnbnansocose: Oy Cyrenae se-secssssecneenee 2 PES PIVENITIS ececas'snaesoouc OS eeATIGVIUS cescccssccrecerses A, 4 \Cy clas) s..vesccasetaccses 1 NEN AGIINR) tossdvavecccxce 1 IPIANOLDIS| cccs-nescncsse. V2) WMIG scsi s-cscncseccascaen 1 DIHCCINCH YE ct occdccccwsces 4 IMGIANIA. sicecevescccoses 2 AlasSMOdON J scc..0000. 1 iaiitth re 12 Potamides.....scccecsees 2 Amodonscchisc.c--se ence 3 Limnea fragilis, a Canadian species, is said to range westward to the Pacific; and ZL. jugularis to be common to Michigan, the North-west territory, and Oregon. (De Kay.) Limncea wmbrosa, Say ? and Planorbis corpulentus, Say, are found in the Columbia River. 20. MEXICAN REGION. The lowlands of the northern half of Tropical America con- stitute only one botanical region, extending from the Rio Grande del Norte to the Amazon; but on zoological grounds it may be divided into two smaller areas. The Mexican province, including Central America, itself comprises three physical regions: the comparatively rainless and treeless districts of the west; the mountains or high table-lands with their peculiar flora; and * The private cabinet of Mr. Jay contains above 200 species of North American Unionide, and very many varieties. : + The affinity between the Mammalia of the Old and New Worlds is greatest in eastern Asia and north-west America, and diminishes with distance from those regions. ( Waterhouse, in Johnston’s Physical Atlas, No. 28.) 110 MANUAL OF THE MOLLUSCA. the rainy wooded region that borders the Cambbean Sea. The - land snails of Central America resemble those of the Antilles in the prevalence of some characteristic genera— Glandina, Cylindrella and Helicina,—of which very few species are found on the northern Coast of the Gulf of Mexico. The Bulimi are numerous, but chiefly thin, translucent species. HIGlIKentetsdesvcereedes (05 Glandinn iy...sss-ceers 25 Cisttla mecessesseusceresmnnl IPTOSETPINA, scsascesoece 1 Tornatellina ............ 1 Cyclophorus .......0+00 3 MS UIMNIUS s.20 5s cecesseeee © 50 PUD Nar osins cone deceesisiaaes 1 Chondropoma. ......... 3 DUCCINED ....5...c0ces00 6 Cylindrella ............ 20 Mepaloma..<.ccccsseases 2 Achatina (Spiraxis) .. 35 Cyclotus ..........c0c08 1 Helicina © iiisc.sessesses 22 Amongst the fresh-water shells are Neritina picta, Cyclas maculata, Corbicula convera, and 7 species of Cyrena. From Mazatlan, Mr. Carpenter describes Cyrena olivacea and Mexicana, Gnathodon trigonus, Anodon ciconia (allied to the Brazilian A. anserina), Physa aurantia and elata, Planorbis sp. Melampus olivaceus. ‘Two brackish-water species, Cerithidiwm varicosum and Montagnei, are common to South America. 21. ANTILLES. The West Indian Islands haye supplied nearly 500 species of Helicide, a larger number than any province except the Lusi- tanian ; and above 260 Cyclostomide, or nearly three times as many as India. They are also richest in generic forms, and the climate is highly favourable to the multiplication of indi- viduals. The mean temperature of the Antilles is 59°—78°, and the annual fall of rain exceeds 100 inches in most of the islands. LENE Resceuctsteetdessess ,.200 PUP Bes eceorass se tsendsans' 26 Cyclophorus .........00. 1 NLENOPUS | heccesee seve 2 Cylindrellavies:-cecsree 73 Cyclotus’ seencssercnener 14 NADU Aa csatesecacsscese sens 20 CLAUS Fs. sc0ssysese 1 Mepalomas,..ses-sdeasae 8 PELOSCEDING.c.ceces cesses 5 IBALC Risks. ss incnseoces acess 1 Helicina ® s<-..sces-e-aee 45 IBULITAUS cr. c2cccves-esess 53 SUCCINGS cossc-se<2 soe 16 AlGAdIG, . cciss peaceerenes 17 ACHAENG 2.05. 2c.008s0- 27 Chondropoma ......... 15 Trochatella, 72.-.csss 16 Glandina, <...<255ss008es 46 Choanopoma............ 53 [meidellay ieciccaceseteee 6 DPITARIS «50siccncessecvace 9 Adamsiella ............ 10 Stoastomiaiic.csssasseays 20 Tornatellina ............ 1 CISbU1S G csncese ce seeps aes 36 Geomelania .......0:..- 21 Probably every island has some peculiar species, and those of the great islands like Cuba and Jamaica are nearly all dis- tinct. To Jamaica belong the species of Stoastoma, Sagda, and _ Geomelania, the small sub-genus Lucidella, the Alcadias and the mass of beautiful Cyclostomas with a decollated spire and fringed lip (Choanopoma, Adamsiella, Jamaica, Chondropoma, . Pe shine COLUMBIAN REGION. LIt part, and Cistula, part.)* The solitary Clausilia is found in Porto Rico, the Balea in Haiti, and the Tornatellina in Cuba; Stenopus is peculiar to St. Vincent’s. Bermuda has 4 Helices, of which one is common to Texas and one to Cuba. The Chondropomas are found in Cuba and Haiti. The West Indian Achatine belong to the sub-genera Glandina, Liguus and Spirawis ; the Bulimi are sharp-lipped and mostly small and slender (Subulina, Orthalicus). Helix (Sagda) epis- tylium, H. Carocolla, and Succinea (Amphibulima) patula are characteristic forms. Although connected with Florida by the chain of the Bahamas, and with Trinidad by the lesser Antilles, very few species are common to the mainland of either North or South America; the relation is generic chiefly. The Limacide are represented by Vaginulus (Sloanei) ; and in the fresh waters there are species of Physa (3), Planorbis (8), Ancylus, and the peculiar Gundlachia, Valvata pygmea, Am- pullaria (fasciata), Paludestrina (minute species), Hemisinus, and 2 species of Pisidium. In the brackish waters are Cerithidium, Neritina (e.g. melea- gris, pupa, virginea, viridis), Melampus (coniformis), and Pedipes quadridens. 22. COLUMBIAN REGION.+ The tract shaded in the map comprehends several minor regions; 1, the rainy and wooded states of New Granada and Ecuador; 2, the elevated and nearly rainless province of Vene- zuela, with a flora like that of the higher regions of the Andes; 3, the Guianas, including the Valley of the Amazon, where the forests are most luxuriant, and rain falls almost daily (amount- ing to 100 or eyen 200 inches in the year). Most of the low lands, like those of the Mexican Proyince, belong to the ‘‘ Cactus Region” of botanists, and have a mean temperature of 68°—84°. Land shells are abundant in the forests and underwood of the lower zone of the mountains, where the temperature is 10° less and the rains more copious. Bulimi are the predominant forms, especially the succinea-shaped species, (e.g. B. succinoides). * A magnificent collection of Jamaica land shells has been presented to the British Museum by the Hon. E. Chittty, whose researches were conducted with the late Professor C. B. Adams. 7 In 1821 the States of New Granada, Venezuela, and Ecuador united to form the « Columbian Republic,” but dissolved again in 1831. 1 MANUAL OF THE MOLLUSCA. RAEI is occ casaoancetaessvop 4D PODG oc sacondcntptanrcveds 7 © Cistules, “cccsasséscapeneane Sine DbAKIS oocct-seeee esse 3) aClauswia, ...cseseeeeaee 4. Bourciers).-cccccssereeee IBOHIMAUS ~.s.s0rs 005.0050 200 Cylindrella,............ 1 Cyclotus zou SSTIGCHICH | Zecaceressocr os 9 WittiNa .ctischeteseeses 1 Adamsiella ......s.s00 1 Tornatellina...........+. 1 WIMAX), weds Saucedo: dacstae 1 Helicina se-.sss Albian %...Je26. Gault. (District of the Aube, or Albe.) 24. Cenomanian Upper Green-sand. (Mans, Cenomanum.) X. < 25. Hippuritic ... | Chalk-marl and L. Chalk = Turonien. i : Chalk with flints = Baculite limestone. \ NS a | Maestricht chalk = Danien, D’Orb. | 2 ie Londinian...... Thanet sands, Plastic clay, London clay. = ae Bracklesham ; Barton; I. Wight; = Parisien. - 28. Nummuliic... Ss renipatend | Fontainblean ; = Tongrien. % XII. 29. Falunian ...... Faluns of Touraine ; Bordeaux, Vienna. &\ XII. 30. Icenian......... Crag of E. Co. = Sub-apennin, D’Orb. It must be observed that the number and magnitude of the ‘‘ Formations’ was determined by accident in the first instance, and afterwards modified to suit the requirements of theory, and — to make them more nearly equal in yalue.* * The names of formations are in great measure provisional, and open to criticism, Some of them were given by Brongniart and O. D’Halloy; others have been more DISTRIBUTION OF MOLLUSCA IN TIME. 119 According to MM. Agassiz and D’Orbigny, all, or nearly all the fossils of each formation are peculiar; very few species being supposed to have suryived from one period to another. Sudden and entire changes of this kind only take place when the nature of the deposit is completely altered—as when sands or clays rest upon chalk—and in these instances there is usually evidence (in the form of beds of shingle, or a change of dip) that an interyal must have elapsed between the completion of the lower stratum and the commencement of the upper. Professor Ramsay* has discussed this subject at considerable length. He endeavours to prove that where we have a com- plete succession of rocks the species die out and appear gradually and almost imperceptiby; that where there is any sudden change in the fauna, it is always accompanied by an unconformity in the rocks—that is, the rocks do not le evenly on one another, but the lower one shows an eroded surface, or its stratifications are not parallel with those of the upper rock. A break in the current of animal life is believed to be always accompanied by a break in the succession of rocks. Hach break marks a lapse of time during which no deposition of mud, &c., took place on the area marked by the break. As it is.assumed that the change of specific forms has proceeded at a uniform rate throughout geological time, it is argued that the greater the difference in the fauna, the longer was the time indicated by the break. ‘‘I cannot resist the general inference that in cases of superposition, in proportion as the species are more or less con- tinuous—that is to say, as the break of life is partial or complete, first in the species, but more importantly in the loss of old and the appearance of new allied or unallied genera—so was the interval of time shorter or longer that elapsed between the close of the lower and the commencement of the upper formation ; and so it often happens that strata a few yards in thickness, or, recently applied by D’Orbigny, Sedgwick, Murchison, and Barrande ; and some are adopted from popular usage. Geographical names, and those derived from charac- teristic fossils have been found the best, but no complete scheme of zoological nomen- clature has been framed. The epithet “Turonien” (25) is rejected, because it conveys the same meaning with “ Falunian” (29), or Middle Tertiary, the type of which was taken from Touraine. The term Jcenian is proposed for the Pliocene strata because their order of succes- sion was first determined by Mr. Charlesworth, in the castern counties of England, the country of the IcENI. We have left the table as it stood in the first edition of this work; but we should mention here that one formation should be placed at the head, viz., the Laurentian, and the beds deposited during and since the glacial epoch at the foot. * Anniversary Addresses, Q. J. Geol. Suc., vols. xix. and xx, 1863 and 1864. 120 MANUAL OF THE MOLLUSCA. more notably still, the absence of these strata, may serve to indicate a period of time as great as the vast accumulations of the whole Silurian series.”’ The lapse of time is in most cases further marked by extensive denudations of strata. During the Palzo-_ zoic age ten physical breaks are known, six of which occu before we reach the Devonian formation. In every case but one (and in that the rocks are almost entirely devoid of animal remains), there is an entire change in the species and a consider- able change in the genera. The breaks in the Secondary period are less marked and less numerous, amounting to about four; and they are still less marked in the Tertiary period. We have seen that distinct faunas may be separated by narrow barriers in existing seas; and differences almost as great may occur on the same coast-line without the interposition of any barrier, merely in passing from a sea-bed of rock and weed to one of sand or mud, or to a zone of different depth. It would be unreasonable to expect the same fossils in a limestone asina sandstone ; and eyen in comparing similar strata we must con- sider the probability of their haying been formed at different depths, or in distinct zoological provinces. The most careful observations hitherto made, under the most favourable circumstances, tend to show that all sudden altera- tions have been local, and that the law of change over the whole globe and through all time has been gradual and uniform. The hypothesis of Sir C. Lyell, that species have been created, and have died out, one by one, agrees far better with facts, than the doctrine of periodic and general extinctions and creations. As regards the zoological value of the ‘‘ formations,” we shall be within the truth if we assume that those already established correspond in importance with geographical provinces; for at least half the species are peculiar, the remainder being common to the preyieus or succeeding strata. This will give to each Geological period a length equal to three times the average duration of the species of marine shells.* The Distribution of the Species in the Strata (or in Time) is like their distribution in space. Each is most abundant m one horizon, and becomes gradually less frequent in the beds above * The exact value of these periods cannot be ascertained, but some notion of their length may be obtained by considering that the deposits in the valley of the Mississippi, «stimated to represent 100,000 years, have been accumulated since the era of many existing shells. The same may be said of the elevation cf Mont Blanc, the formation of the Mediterranean Sea, and other grand physical «vents. The great cities of anti- quity—Rome, Corinth, and Egyptian Thebes—stand upon raised sea beds, or alluvial deposits. containing recent shells. Zi ‘9 "3 @ ; q . DISTRIBUTION OF MOLLUSCA IN TIME. 121 aud below; the locality of the newest rock in which it occurs being often far removed from that of the oldest.* That species should be created at a single spot, and gradually multiply and diffuse themselves, is sufficiently intelligible. That, after attaining a certain climax of development, they should decline and disappear, is a fact involved in mystery. But even if it depends on physical causes, and is not a law of all Being, its operation is equally certain, and does not appear to vary beyond moderate limits. The deep-sea shells (such as Rhynchonella, Terebratula, and Yoldia) enjoy a longer range in time, as well as in space, than the littoral species; whilst the land and fresh-water shells are most remarkable for specific longevity.+ In each stratum there are some fossils which characterise small subdivisions of rock, just as there are living species of very limited range. When species once die out they never reappear; one evidence of their haying become extinct consisting in their replacement by other species, which fulfilled their functions, and are found in deposits formed under similar conditions. (Forbes.) The total number of species is greater in the newest forma- tions than in those of older date; but the ratio of increase has not been ascertained.} Distribution of Genera in Time.—The doctrine of the Identi- fication of strata by fossils derives its chief value from the fact that the development and distribution of genera is as much sub- ject to law as the distribution of species; and, so far as we know, follows a similar law. Groups of strata, like the zoological provinces, may be of various magnitudes; and whilst the smaller divisions are cha- racterised by peculiar species, the larger groups have distinc* sub-genera, genera, and families, according to their size and importance. William Smith himself observed that ‘‘three principal families of organised fossils occupy nearly three equal parts of Britain.” * M. Agassiz and Professor E. Forbes have represented, diagrammatically, the distribution of genera in time, by making the horizontal lines (such as in p. 124) swell out in proportion to the development of the genera. Those whose commencement, climax, and end are ascertained may be represented by a line of this kind — greg Genera which attain their mazima in the present seas are thus expressed ——eagy 7 Land and fresh-water shells of existing species are found with the fossil bones of the Mastodon and Megalonyr, in N. America. (Lyell.) } The number in each formation depends on the extent to which it has been investi- gated, and on the opinions entertained as to the strata referable to it. Professor Phillips has discussed this esbject in his work on Devonian fossils (p. 165), and in the “Guide to Geology.” G 132 MANUAL OF THE MOLLUSCA. ‘‘ Hchini are most common in the superior strata ; “* Ammonites to those beneath 3. “¢ Producti, with numerous Encrini, to the lowest.” This kind of generalisation has justly been considered by Pro- fessor Ei. Forbes of higher importance than the identification of strata by species—a method only applicable to moderate areas, and becoming less available with distance. Indeed it might be assumed that strata geographically distant, yet containing some identical species, must differ in age by the time required for the migration of those species from one locality to the other. A table of the characteristic species of the English strata is of little use in America or India, except to show how few and doubtful are the identical fossils. "Whereas the characteristic genera and order of succession of the larger groups are the same at the most distant localities; and whatever value there may be in the assumption that particular systems of rocks con- tain most workable coal, lead, or rock-salt, is not lessened by the circumstance that the species of fossils in those rocks are not everywhere the same, since the genera alone are sufficient to identify them. Genera, like species, have a commencement, a climax, and a period of decline; the smallest usually range through several formations, and many of the typical genera equal the families in duration. Groups of formations are called Systems, and these again are combined in three principal series :—Palzeozoic, Secondary, and Tertiary. Thirteen geological systems, each haying a number of peculiar genera, are shown in the accompanying table. (No. II.) Some of the genera cited have a wider range, like Belemnites, but are mentioned because of their abundance in one particular system. The names in italics are existing genera.* The third table contains the names of some of the larger genera, arranged according to the order of their appearance. This diagram conyeys the impression that the series of fossili- ferous strata is not completely known; or that the beginning of many groups of fossils has been obliterated in the universal metamorphism of the oldest stratified rocks.t * The Plivcene strata contain no extinct genera, and represent only the commence- ment of the present order of things. All the deposits now taking place will not consti- tute en additional “‘ Formation,” much less a ‘‘ Quaternary System,” + It was on this account that Professor Sedgwick proposed the term “ Palzozoie, * . rather than “ Protozoic,” for the oldest fossiliferous rocks, BEPHOCENE, ccccsccsnccces TABLE OF CHARACTERISTIC GENERA. 123 II. TABLE OF CHARACTERISTIC GENERA. SYSTEMS. GENERA AND SUB-GENERA. ‘Camaroceras, Endoceras, Gonioceras, Pterotheca. 1, CAMBRIAN, or Maclurea, Raphistoma, Holopea, Platyceras. Lower Silurian ..... Orthisina, Platystrophia, Porambonites, Pseudo-crania. Ambonychia, Modiolopsis, Lyrodesma. { Actinoceras, Phregmoceras, Trochoceras, Ascoceras. SE ELAREAN: oc .ccssc0.s- Theca, Holopella, Murchisonia, Atrypa, Retzia. Cardiola, Clidophorus, Goniophorus, Grammysia. Bactrites, Gyroceras, Clymenia, Apioceras, Serpularia. Oy DEVONIAN, .occscccsees < Spirifera, Uncites, Merista, Davidsonia, Calceola. Stringocephalus, Megalodon, Orthonota, Pterinea. Nautiloceras, Discites, Goniatites, Porcellia. 4. CARBONIFEROUS... Naticopsis, Platyschisma, Metoptoma, Productus. Aviculo-pecten, Anthracosia, Conocardium, Sedgwickia. Camarophoria, Aulosteges, Strophalosia. Myalina, Bakewellia, Axinus, Edraondia. on BORER MEAN ..cccccccece Ceratites, Naticella, Platystoma, Koninckia, Cyrtia, Monotis, Myophoria, Pleurophorus, Opis. for) PRUE EASiscssacccsacceescs Alaria, Trochotoma, Rimula, Pileolus, Cylindrites. Waldheimia, Zhecidiwm, Spiriferina, Ceromya. Gryphea, Hippopodium, Cardinia, Myoconcha. . L. JURASSIC ......... = {sian Beloteuthis, Geoteuthis, Ammonites. Coccoteuthis, Leptoteuthis, Nautilus. Spinigera, Purpurina, Nerinzea, Neritoma. Pteroperna, Trichites, Hypotrema, Diceras. Trigonia, Pachyrisma, Sowerbia, Tancredia. ao Pad OIRASSIC ..cscss0s Crioceras, Toxoceras, Hamulina, Baculina. Requienia, Caprinella, Sphera, Thetis. 9. L. CRETACEOUS ... ; Belemnitella, Conoteuthis, Turrilites, Ptychoceras. Hamites, Scaphites, Pterodonta, Cinulia, Tylostoma. Acteonella, Globiconcha, Trigonosemus, Magas, Lyra. Neithea, Inoceramus, Hippurites, Caprina, Caprotina. 10. U. CRETACEOUS... Beloptera, Lychnus, Megaspira, Glandina, Typhis. Volutilithes, Clavella, Pseudoliva, Seraphs, Rimella. Conorbis, Strepsidura, Globulus, Phorus, Velates. Chilostoma, Volvaria, Lithocardium, Teredina. Spirulirostra, Aturia, Vaginella, Ferussina. Halia, Proto, Deshayesia, Niso, Cassidaria, Carolia. Grateloupia, Artemis, Tapes, Jouannetia. 12. MIOCENE ....0..00.0. Argonauta, Strombus, Purpura, Trophon. Yoldia, Tridacna, Circe, Verticordia. BE GIOCEN TE, ..cccccccsce a2 124 MANUAL OF THE MOLLUSCGA, III. RANGE OF GENERA IN TIME. Genera, arranged in their Order of Appearance. Cambrian. Silurian Devonian. Carbonif. Permian. L. Jura, U. Jura. L. Cret U. Cret Eocene Miocene, Pliocene. Trias. Lituites, Raphistoma, Obolus ..........0.06 — Camaroceras, Atrypa, Pterinea ............ —_——— Gomphoceras, Bellerophon, Pentamerus | —— — — Orihisonularia, Murchisonia...c.csneco |e 2 Spirifera, Athyris, Posidonomya...... ..... | ———— — — BEEBE epee ct oeeec secre scnesssusacsdncstiactaware Conocardium, Megalodon, Chonetes ATOIOMONPHA G2, Sadeewerocsdecs gaesvasdeeee eke — Orthoceras, Loxonema, Cyrtia..............5 ————j|— Pleurotomaria, Porcellia — Productus, Macrochilus, Streptorhynchus _-—-— Goniatites, Pleurophorus ..........0.c...0eee —_——/— Edmondia, Myalina............ Bexhenartoccees bs _— MEER Rss: cieapadiNiec teatime fa) Derebratula, Pinna, Cyprind..:....0..c00000 | 0 ee | NI pscivsunaieoesdedeScsicvavesesesisasccdhesses el ——— EpervaiA NEV OCOUCDS 504.5 .ccaccss0cesacasacenes Ammonites, Naticella, Opis ......cccc0ces0n | | aa cae Trigonia, Isocardia, Thecidium ............ Cermtisum, Plichtola, Cardita ....cc000] 4. =z == +> Trochotoma, Tancredia, Gryphza ......... Ancyloceras, Inoceramus, Unicardium ... ---— Astarte, Pholadomya, Corbis ............... ——-—--—-|--— Nerinza, Goniomya, Exogyra...........008. ==> Terebratella, Limopsis, Nezra, Argiope ... ee Baculites, Cinulia, Radiolites ............... — : Physa, Paludina, Unio, Cyrena ......:..... —_——|--—— | Aporthais, Tornatella, Pyrula ...........6 1 | - — | Pectunculus, Thetis, Crassatella ............ a | TENN. CHARI tus sdewascndes eck taaterexulhavees —|--— , Voluta, Conus, Mitra, Haliotis, &c.......... || SAU pee ae ea OB Aare ry gl ie See ea == Helix, Auricula, Cyclostoma ............... Pseudoliva, Rostellaria, Seraphs ............ PALPULA, OLE OWIPUS ie v2 sadeuseeses meleevousceees a The genera of the older rocks are believed to be nearly all extinct; for although the names of many recent forms appear in the catalogues of Palzeozoic fossils, it must be understood that they are only employed in default of more exact infor- mation. Buccinum, Melania, and Mya have been long since expunged; and Modiola, Nucula, and Natica, are only retained until the characters which distinguish them are better under- stoad, RANGE OF FAMILIES IN TIME. 125 IV. RANGE OF FAMILIES IN TIME. a .8e¢4 7 rar iat Systems } B£eS28| ddedleeee of Strata FE EE Ze eSo $338 = ek? ta) i =e ee Ss = _ |Saaoe BHpHbpl|pasaar PRET MOMENI, cen eecac:ovrcsces sae ssaseres —— Teuthidee—Sepiade ..........ccceeeeeeee fo fee —————— REED IEICE oe case ccccs dics sseeccsessenssess a Nuutilide......, Pe ra ack aou coe ca nacecoaes SS oe | CURRED Ghee ee ‘ Orthoceratidee ...........cceceeeeeteeeeeeees | — —— — — = Atlantidee—Hyaleide .............0.0086. | ——— — — | — —— — — SS Strompbidz—Buccinide ............seeee — ee MEQHIGG——“VOLUEIGE oa c.ccccccecccccesceeees — | = SS Naticidee—Calyptreeidee .............ec0ee |) ee Pyrarmidelide ...........c.cceeceeeeeseeeeee | — = — — | — — — — — a. Ss Beniets —MInOLINIGG ...cccoceeeees | ll SS ey = Turbinidze—lIanthinide .................. | — — — — — | — — — — — os Fissurellide—Tornatellide............... | ee ee aS ee Erte —PALCIIIA .....0cccccecccesseses ve } ————|———— PrEREA RENEE eine Soccer esis ioeetsacsecasere-s Se ee 253 See MPIIIGGO 8 fo ccc iesccccsceceesss2esce.ec-0-008 | —— —— | eee eye PORE nn cian noes aicelsscecnsiesiecsnscce Se ee EPEIICICCE—LATMACIOG .......0ccccecccsenee = Limnzidee—Melaniade .............00262 | 8 §©=©°>[. ———f[———— Auriculide—Cyclostomide............+ —|———— BP ESISERERNIO DD ccescseccsectscsesecesccostereess ee eee ee eee | Rhynchonelide ........sccceeeeesseseeeeeeeee | = — — — | —— —— — ee Spiriferidzee—Orthidée ...............00088. | ——— — — a PPEOOUCTIO '.....c.0ccccccscecvcsccevccccsscesee | —— —-——— Craniadee—Lingulide ..........0eeee | ————— | ——-—-— — | —--— ete EIST oy ins cick neciceaeeseceseneels a et clei it Bete Aviculide—Mytilide..........cs0ecceeeeeeee | = — — — | — — —— — | —— — — Arcade—Trigoniade ..........s:eeeee | ———— — | —— — — — aan ae RERRETPEIBE ies ono nics cocousseucnsesedvocese a) eee Chamide—Myada.......ccccseeeseeereerree | ee SMNMENNEIEL CE cave sececescacsssoncsoucses aren — MIP REATOR one ons sccidsecsdesivsceess esc — WardiaG2—LUCINIGR. ........0.cccccccsseees —— = =, | SS Se SS eee UMIEERIE a gas eons; >] period in which they fiourished. The introduction of new forms, also, is more rapid than the process of extinction. If four Palseozoic families disappear, twenty-six others replace them in the Secondary series; and three of the latter are succeeded by fifteen shell-bearing families in the Tertiary and existing seas. In consequence of this circumstance, the number of types is three times greater in the newer Tertiary than it was at the Silurian period; and since there is no evidence or indication that the earth was ever destitute of life, either wholly or in part, it follows almost as a matter of necessity that the early types must have been more widely distributed and individually developed, than those of the present day. From the following Table it will be seen that the number of genera and families increases with an amount of regularity which cannot be accidental. Moreover, the relation of these numbers is not liable to be much altered by the progress of discovery or the caprice of opinion. The discovery of new types is not likely to be frequent; the imposition of new names, in place of the old, will not increase the number of Palzozoic — genera; and the establishment of fresh and arbitrary distinc- tions will affect all the groups in due proportion. If the number of groups called ‘‘ Systems” were reduced to seven (viz., three Palzeozoic, three Secondary, and one Tertiary, as shown in the following Table), then the average duration of a genus of shells would be equal to a System of Formations. The duration of the smallest well-defined Families of shells is about equal to one of the three great Geological Divisions, or Ages. — ape MY oo ee DISTRIBUTION OF MOLLUSCA IN TIME. 127 DEVELOPMENT OF FAMILIES, GENERA, AND SPECIES, IN TIME. | di¢|41. Soe s: |r Tota GEOLOGICAL pe B18) 2 = || Number of | 2 SYSTEMS. Genera] 3] 5] 2/4 Species FS Se eis = | (D’Orbigny).| 3 ie) ie) ea) o ey iS Cambrian......csseseesees: ag | 12] 11 | 15] 1 362 | 18 5 ‘Sa ree 53 3} 11} 16] 13 317 20 tee OVOHIAD ......:...0000000 77 14 | 20 | 23 | 20 1035 24-32 5 § Carboniferous ............ 79 IL | 26 | 19 | 23 835 BO] -i a SPBOCMUAR 5. :...ccereessee 66 6 | 24 | 16 | 20 74 30 o 9 ee 81 9 | 25| 16] 3 713 35 ) = 5 JL. Jurassic ...........04. 107 TOA Soe) Len as 1502 42} p RURVETASSIC so hc.caccecces 108 132 (0865) 9a +50 1266 49 bn Sl 6 fe Cretaceous ....060:.c<- 123 20 | 41 9 | 53 78 52 B We Cretaceous:.........-- 148 16 5901) ta |59 2147 56 ) nN Nex! ee SNE Efe . = e Eocene Be orc sactyoeneaass ccs 172 Asal eee T 2636 60 < J) 7+ Miocene ..............000 178 Se OE GG 2242 60 79 = IEMIGEENUN.cocoseec--o20nees 192 1 |1G0 | 12} 79 -43 62‘ Fs BMPR ie ecccvsesiciadees 400 | 21 |251 | 13 {115 |] 16,000 78 aH ta a ae ee Se ee ee eee Recent & Fossil......... 520 | 56 [280 | 34 [150 j} 30,000 | 85 | Order of Appearance of the Groups of Shells.—The first and most important point shown in the preceding Tables, is the co- existence of the four principal classes of festacea from the earliest period. The highest and the lowest groups were most abundant in the palzeozoic age; the ordinary bivalves and univalves attain their climax in existing seas. If there be any meaning in this order of appearance it is connected with the general scheme of creation, and cannot be inquired into separately ; but it may be observed that the last-developed groups are also the most typical, or characteristic oy their class (p. 49). The Cephalopoda exhibit amongst themselyes unmistakable evidence of order in their appearance and succession. The tetrabranchiate group comes earliest, and culminates about the period of the first appearance of the more highly-organised cuttle- fishes.t The families of each division which are least unlike * Those genera are estimated as belonging to each system which occur in the strata both above and below, as well as those actually found in it. We have left this table as it stood in the first edition, as we are unable to correctall the figures. This, however is not of much importance, since the main points, such as the gradual increase in the number of families, would not be affected. + The Palaoteuthis of Broun (not D’Orb.) appears to be a /ish-bone, from the equ'va ent of the Old Red sandsto», in the Eifel. 128 MANUAL OF THE MOLLUSCA. (Orthoceratidee and Belemnitide) were respectively the first de- veloped. Amongst the Brachiopoda the hingeless genera attained their maximum in the palozoic age, and only three now suryiye (Lingula, Discina, Crania,)—the representatives of as many distinct families. Of the genera with articulated valves, those provided with spiral arms appeared first and attained their maximum while the Terebratulide were still few in number. The subdivision with calcareous spires disappeared with the Liassic period, whereas the genus Rhynchonella still exists. Lastly, the typical group, Terebratulide, attained its maximum in the chalk period, and is scarcely yet on the decline. The number of seb-genera (as well as genera) in each system is stated in the preceding table, because this group shows a ten- dency to ‘‘ polarity,” or excessive development at the ends of the series.* The genera of ordinary bivalves (Conchifera) are seven times more numerous in the newer tertiary than in the oldest geo- logical system. The palzeozoic formations contain numerous genera of all the families with an open mantle; Cyprinide, Anatinide, and the anomalous genus Conocardiwm. The mass of siphonated bivalves do not appear till the middle of the secondary age, and are only now at their maximum. The Gasteropoda are represented in the palzeozoic strata by seyeral genera closely allied to the diminutive Atlanta and Scissu- rella, and by others perhaps related to Janthina. The Naticide and Calyptreide are plentiful, and there are several genera of elongated spiral shells referred to the Pyramidellide. In the secondary strata, holostomatous shells become plentiful; and in a few peculiar localities (especially Southern India) the genera of siphonated univyalves make their appearance in strata of Cretaceous age. Fresh-water Pulmonifera of the recent genus Physa occur in the Purbeck strata, but the marine air-breathers and land-snails have not certainly been found in strata older than the Eocene tertiary. Order of Succession of Groups of Shells.—It has been already pointed out that animals which are closely allied in structure * See the anniversary address of Professor E. Forbes to the Geological Society of London, Feb., 1854, p. 63. The hypothesis seems to have arisen out of an exclusive regard to the poverty of the Permian and Triassic strata in England, where they separate, like a desert, the paleeozoic from the ‘‘ neozoic”’ formations. The ‘‘ Permian” should never have been esteemed more than a division of the carboniferous system, and is poor in species, rather than in types. The Trias must be studied in Germany, or in the collection of Dr. Klipstein (in the British Museum) to be properly appreciated. DISTRIBUTION OF THE MOLLUSCA IN TIME. 129 and habit rarely live together, but occupy distinct areas, and are termed ‘‘ representative species.”’ The same thing has beer observed in the distribution of fossils; the species of successive strata are mostly representative. At wider intervals of time and space, the representation is only generic, and the ee proportions of the larger groups are also changed. The succession of forms is often so regular as to mislead a superficial observer; whilst it affords, if properly investigated, a valuable clue to the affinities of problematic fossils. It is now generally admitted that the earlier forms of life, strange as many of them seem to us, were really less meta- morphosed—or departed less widely from their ideal archetypes —than those of later periods and of the present day.* The types first developed are most like the embryonic forms of their respective groups, and the progression observed is from these general types to forms more highly specialised. (Owen.) Migration of Species and diffusion of Genera in Former Times.— Having adopted the doctrine of the continuity of specific and generic areas, it remains to be shown that such groups as are now widely scattered can haye been diffused from common centres, and that the barriers which now divide them haye not always existed. In the first place it will be noticed that the mass of the stratified rocks are of marine origin, a circumstance not to be wondered at, since the area of the sea is twice as great as the land, and probably has always been so; for the average depth of the sea is much greater than the general elevation of the land.+ The mineral changes in the strata may sometimes be accounted for by changes in the depth of the sea, or an altered direction of the currents. But in many instances the sea-bed has been elevated so as to become dry land, in the interval between the formation of two distinct marine strata; and these alterations are believed to occur (at least) once in each formation. If every part of what is now dry land has (on the average) * Mr. Darwin has pointed out that the sessi/e Cirripedes, which are more highly metamorphosed than the Lepadide, were the last to appear. The fossil mammalia afford, however, the most remarkable examples of thislaw. At the present day such an animal as the three-toed horse (Hippotherium) of the Miocene Tertiary would be deemed a dusus nature, but in truth the ordinary horse is far more wonderful. Un- fortunately, a new “ vulgar error” has arisen from the terms in which extinct animals have sometimes been described, as if they had been constructed upon several distinct types, and combined the character of several classes. 7 The enormous thickness of the older rocks in all parts of the world has been held to indicate the prevalence of deep water in os primeeval seas, G 130 MANUAL OF THE MOLLUSCA. been thirty times submerged, and has formed part of the sea- bed during two-thirds of all the past geological time,—there will be no difficulty in accounting for the migration of sea-shells, or the diffusion of marine genera. On the other hand, it may be inferred that every part of the present sea has been dry land many different times; on an average not less than thirty times,—amounting to one-third of the whole interval since the Cambrian epoch. The average duration of the marine species has been assumed at only enethird the length of a geological period, and this harmonises with the fact that so few (either living or extinct) have a world-wide distribution. The life of the land-snails and of the fresh-water shells has been of longer average extent, enabling them to acquire a wide range, notwithstanding their tardy migrations. ' But when we compare the estimated rate of change in physical geography with the duration of genera and families of shells, we not only find ample time for their diffusion by land or sea over large portions of the world, but we may perceive that such transferences of the scene of creation must haye become in- eyitable. Method of Geological Investigation.—In whatever way geo- logical history is written, its original investigators have only ‘one method of proceeding—from the known to the unknown— or backwards in the course of time. The newest and most superficial deposits contain the remains of man and his works, and the animals he has introduced. Those of pre-historic date, but still very modern, contain shells, &c., of recent species, but in proportions different from those which now prevail (pp. 89, 90, 93). Some of the species may be extinct in the immediate neighbourhood of the deposits, but still living at a distance. In the harbour of New Bedford are colonies of dead shells of the Pholas costata, a species living on the coast of the Southern States. At Bracklesham, Sussex, there is a raised sea-bed containing 35 species of sea-shells living on the same coast, and 2 no longer living there, viz.—Pecten polymorphus, a Medi- terranean shell; and Lutraria rugosa, still found on the coasts of Portugal and Mogador. Tertiary Age.—If any distinction is to be made between ‘‘ Tertiary” and ‘‘ Post-tertiary”’ strata, the former term should be restricted to those depcsits which contain some extinct species. And the newest of these, in Britain, contain an assemblage of Northern shells. Professor Forbes has published a list of 124 ol DISTRIBUTION OF THE MOLLUSCA IN TIME. 13i species of shells from these ‘‘ Glacial beds,” nearly all of which are now existing in British seas.* In most of the localities for glacial shells, the species are all recent; but at Bridlington, Yorkshire, and in the Norwich Crag, a few extinct species are found (e.g. Nucula Cobboldie, Pl. 17, f. 18). At Chillesford, Suffolk, Yoldia arctica and myalis occur of large size and in excellent preservation, with numerous specimens of Mya truncata, erect as they lived, in the muddy sea-bed. Trophon scalariforme, Admete viridula, Scalaria gren- landica, and Natica grenlandica, also occur in the Norwich Crag ; and Astarte borealis, with several arctic forms of Tellina, are amongst the commonest shells, and frequently occur in pairs, or with their ligament preserved; the deposit is extensively quarried for shell-sand. Raised sea-beds with Arctic shells at Uddevalla, in Sweden, haye been repeatedly noticed ever since the time of Linnzeus. Captain Bayfield discovered similar beds near Quebec, 50—200 feet above the River St. Lawrence, containing an assemblage of shells entirely Arctic in character; whereas in the present gulf he cbtained an admixture of the American representatives of Lusitanian types, Mesodesma, Periploma, Petricola, Crepidula. The glacial deposits of the northern hemisphere extend about 15° south of the line of ‘“‘ northern limit of trees ;” but this comparatively recent extension of the Arctic ocean does not appear to have much influenced, if it ever invaded, the inland basin of the Aralo-Caspian, which contains only one species common to the White Sea, Cardiwm edule, var. rusticwm.t The older pliocene period is represented in England by the Coralline Crag, a deposit containing 340 species of shells. Of these 73 are living British species, but (with two or three ex- ceptions) they are such as range south of Britain. (Forbes.) The remainder are extinct, or living only to the south, especially in the Lusitanian province: e.g. Fossarus sulcatus, Lucinopsis Lajonkairii, Chama gryphoides, and species of Cassidaria, Cleo- dora, Sigaretus, Terebra, Colwmbella, and Pyramidella. It also contains a few forms belonging to an earlier age—a Pholadomya, a true Pyrula,a Lingula, and a large Voluta, resembling the Magellanic species. * The species which have retired farther north are marked (**) in the preceding Arctic List, pp. 57, 58. 7 Mr. Wm. Hopkins, of Cambridge, has investigated the causes which may have produced a temporary extension of the Arctic phenomena in Europe; and considers the most efficient and probable cause would be a diversion of the Gulf-stream, which _ he supposes to have flowed up what is now the valley of the Mississippi. (Geological Journal), 132 MANUAL OF THE MOLLUSCA. The shells of the newer tertiaries are always identical, at least generically, with those of the nearest coasts. Thus, in Pata- gonia are found species of Trophon, Orepidula, Monoceros, Pseudoliva, Voluta, Oliva, Crassatella, and Solenella. The ter- tiaries of the United States contain species of Fulgur, Mercenaria, and Gnathodon. The miocene shells of St. Domingo appear at first sight to be all of recent species, but on comparison prove to be mostly distinct. The proportion of extinct species in the Pliocene tertiary varies from 1—40 per cent. If a deposit contains more than 50 per cent. of extinct species it is referred to the Miocene period; and this test is particularly valuable since the modern deposits are often isolated, and frequently no assistance can be derived from superposition, or even from identity of species. In the Locene tertiaries we perceive the ‘‘dawn”’ of the present order of things. All, or very nearly all, the species are different, but a large proportion of the genera are still existing, though not always in the seas nearest to the localities where they occur fossil. Thus in the London clay are found—Rostellaria, Oliva, Ancil- laria, and Vulsella, genera still living in the Red Sea; and many species of Nautilus, Rimella, Seraphs, Conus, Mitra, Pyrula, Phorus, Liotia, Cardilia—genera characteristic of the Indian Ocean; Cyprovula, Typhis, and Volutilithes, now living at the Cape; Clavella, at the Marquesas, and Pseudoliva, Trochita, and species of Murex, whose recent analogues are found on the western shores of South America. The freshwater shells of this period are Old World forms: Melanopsis, Potamides, Lampania, Melanatria, and Nematura ; whilst the land-shells form a group quite American in character —large species of Glandina and Bulimus (with reflected lip) Megalomastoma (mumia), a Cyclotus (with its operculum) like C. Jamaicensis, and the little Helix labyrinthicus. Secondary Age.—In none of the older strata do we find indica-~ tions of a warmer climate having prevailed, in the latitude of England, than that which marks the period of the London clay. And this is not more than can be accounted for by such a cause as the flow of an equatorial current from the direction of the Red Sea, until arrested by a continent to the south-west, as supposed by Mr. Prestwich, in the region of the Azores. Some indications exist of a more moderate climate haying | obtained in the north polar regions; for remains of the Ichthyo- saurus were found at Exmouth Island, the farthest point reached by Sir E. Belcher’s expedition. DISTRIBUTION OF THE MOLLUSCA IN TIME. 133 The peculiar physical conditions of the Chalk period are represented at the present day, not so much by the Coral Sea, as by the Aigean, where calcareous mud, derived from the waste of the scaglia regions, is being rapidly deposited in deep water. (Lorbes.) The Wealden period was styled the ‘‘ Age of Reptiles” by Dr. Mantell, who compared the state of England at that time with the present condition of the Galapagos Islands. The Oolitic period finds its parallel in Australia, as long since pointed out by Professor Phillips, and the comparison holds good to some extent, both for the Marine and Terrestrial Faunas. The Trias, with its foot-prints of gigantic wingless birds, has been compared with the state of the Mascarene Islands only a few centuries ago, and with the New Zealand Fauna, where birds are still the highest aboriginal inhabitants.* Paleozoic Age.—It has lately been shown by Professor Ramsay that signs of glacial action may be traced in some of the trappean conglomerates of the Permian and of the Devonian or Old Red Sandstone period in England ; and Mr. Page has endeavoured to apply the same interpretation to phenomena of a similar cha- racter in the Old Red sandstone of Scotland.+ Geologists gene- rally haye abandoned the notion, once yery prevalent, of a universal high temperature in the earliest periods; a notion which they had derived from the occurrence of certain fossil plants, corals, and shells in high latitudes. The absence of remains of mammalia in the paleeozoic forma- tions, is at present a remarkable fact, but it is completely paralleled in the great modern zoological province of the Pacific Islands. Baron Humboldt has speculated on the possibility of some land being yet discovered, where gigantic lichens and arborescent mosses may be the princes of the vegetable kingdom.{ If such exist, to shadow the Paleozoic age, its appropriate inhabitants would be like the cayern-haunting Proteus, and the Silures which find an asylum eyen in the craters of the Andes. What, then, is it which has chiefly determined the character of the present zoological provinces? What law, more powerful than climate, more influential than soil, and food, and shelter ; * In a paper read before the British Association, on the subject of the great extinct _ Wingless birds of New Zealand, Professor Owen suggested the notion of land having been propagated like a wave throughout the vast interval between Connecticut and Nw Zealand, since the Triassic period. J See also the Rev. J. G. Cumming’s “Isle of Man” (1849), p. 89. }¢ Views of Nature, p. 221. Bohn’s ed. 134 MANUAL OF THE MOLLUSCA. nay, often seemingly producing results opposed to @ priori probability, and at variance with the suitableness of con- ditions ?* The answer is, that each fauna bears, above all things, the impress of the age to which it belongs. Each has undergone a series of vicissitudes up to the time when its barriers became fixed, and after its isolation it has known no further change, but decline. The number of living and fossil species of each genus of mollusca will be stated in the following pages, so far as they can be ascertained. With some modifications, these numbers give the following totals, by which the relative numerical development of the orders and families will be seen. Recent. Fossil. Recent. Fossil CEPHALOPODA. Dibranchiata. Neritidge scrccs.s sec) Fees! cos 18 1v0-8' Morrisia anomioides ... ... .s. L 0 CEAMIAMITIOCNS! © asl ces) acs ese 0 6" Lima elongata 0 5’ Pecten concentricus 0 1’ » fenestratus... 0 2’ Spondylus Gussoni... 1 ie Arca lactea 1 7h s» scabra 0 2' Nevra cuspidata 0 il » attenuata 0 WY Fusus echinatus 50° Gog noe 0 2 Pleurotoma crispata ... 1... ve. 0 2 aA maravione... ... 0 2 abyssicola 539 coe 0 4 Mitra ‘philippiana co co one 0 4 Cerithiom dima § ... 0 ies) tee 0 8 Trochus tinel ... <0. sss. ves 0 6 99 CXIQUUS 26. ose ose 1 9 Turbo sanguineus ... ... 0 24 Rissoa reticulata ... 12. see eee 4 lL Emarginula elongata ... ... ... 0 8 Pileopsis Hungaricus ... ... 0 1 ACMA UNICOLOM 5 4 ces: coe iL 24 Atlanta Peronii .... ses se 0 2 Hyalea gibbos2 =... seo wee 0 LY Cleodora pyramidata ... ... ... 0 3 (CFISCIBICIAVA Gsoc8- see nave lose) eee 0 7 Bsn RPINILCTA. a sasticce ee sa cee 0 10 Ne DAS eecs) ees eres bese ENON Cot, C4) ee MAOCHIIEY) eee) nes aces Ue SUN a de era: oe5 Distance from shore ... ASTOUNG Se pee) sseh bese 230 fathoms. Fine yellowish mud. Terebratula vitrea ... ... see see 0 2’ Syndosmya profundissima Scoumter 0 3’ Arca imbricata... 1 1’ Dentalium quinquangulare ... ... 1 0 Hyalea gibbosa - .... ss. ses oes 0 1 Cleodora pyramidata ... ... ... 0 8 Criseis spinifdra . i... bes. a ee ee ee ee ee ety ee CEPHALOPODA. 201 HAmITES, Parkinson. Etymology, hamus, a hook. Example, H. attenuatus (Pl. III., Fig. 15). Shell hook-shaped, or bent upon itself more than once, the courses separate. Distribution, 58 species. Neocomian—Chalk. South Amorica (Tierra del Fuego), Europe, India. 2 : Fig. 65. Sutures of Hamites cylindraceus, Defr.* The inner courses of this shell probably break away, or are *‘decollated,” in the progress of its growth. (Torbes.) M. D’Orbigny has proposed a new genus, hamulina, for the twenty neocomian species. PrycHoceRAs, D’Orbigny. Etymology, ptyche, a fold. Example, P. emericianum, D’Orbigny (Pl. III., Fig. 14). Shell bent once upon itself; the two straight portions in contact. Distribution, 8 species. Neocomian—Chalk. Britain, France, India. BaAcu.itEs, Lamarck. Etymology, baculus, a staff. Example, B. anceps (Pl. III., Fig. 13). Shell straight, elongated; aperture guarded by a dorsal process. Distribution, 17 species. Neocomian—Chalk. Europe, South America (Chili), India. Baculina, D’Orbigny, 2 species. B. Rouyana. Neocomian. France. Sutures not foliated. The chalk of Normandy has received the name of. baculite lime- stone, from the abundance of this fossil. * Fig. 65. Space between two consecutive sutures of the right side, from a specimen inthe British Museum. a, dorsul line; 6, ventral. Baculite limestone, Fresville, K 3 202 MANUAL OF THE MOLLUSCA. CHAPTER II. CLASS IL.—GASTEROPODA. The gasteropods, including land-snails, sea-snails, whelks, limpets, and the like, are the types of the mollusca ; that is to say, they present all the leading features of molluscous organisa- tion in the most prominent degree, and make less approach to the appearance and condition of fishes than the cephalopods, and less to the crustaceans and zoophytes than the bivalves. Their ordinary and characteristic mode of locomotion is exemplified by the common garden-snail, which creeps by the successive expansion and contraction of its broad muscular foot. These muscular movements may be seen following each other in rapid waves when a snail is climbing a pane of glass. The nucleobranchs are ‘‘ aberrant” gasteropods, haying the foot thin and vertical; they swim near the surface of the sea in a reversed position, or adhere to floating sea-weed. WWE Fig. 66. A nucleobranch.* The gasteropods are nearly all unsymmetrical, the body being coiled up spirally, and the respiratery organs of the left side being usually atrophied. In chiton and dentalium the branchie and reproductive organs are repeated on each side. A few species of cymba, littorina, paludina, and helix, are yivi- parous ; the rest are oviparous. __ When first hatched the young are always provided with a shell, though in many families it becomes concealed by a fold of the mantle, or it is speedily and wholly lost.+ The gasteropods form two natural groups; one breathing air * Fig. 66. Carinana cymhium, Desh. = C. cristata, L. sp. (after Blainville), Medi- terranean. p, proboscis; t, tentacles ; b, branchiz; s, shell; f, foot; d, disk. t M. Lovén believes that the embryo shell of the nudibranchs falls off at the time they acquire a locomotive foot. GASTEROPODA. 208 (pulmonifera), the other water (branchifera). The water-breathers haye at first a small nautiloid shell, capable of concealing them entirely, andclosed by an operculum. Instead of creeping, they swim with a pair of ciliated fins springing from the sides of the lead ; and by this means are often more widely dispersed than we should be led to expect from their adult habits ; thus some sedentary species of calyptrea and chiton have a greater range than the ‘‘paper-sailor,” or the ever-drifting oceanic-snail. At this stage, which may fairly be compared with the larval condition of insects, there is scarcely any difference between the young of Fig. 67.* eolis and aplysia, or buccinum and vermetus. (M. Edwards.) The development of the branchiferous gasteropods may be observed with much facility in the common river-snails (palu- dina); which are viviparous, and whose oviducts in early summer contain young in all stages of growth, some being a quarter of an inch in diameter. Fig. 68. Paludina vivipara.t Embryos scarcely visible to the naked eye have a well-formed shell, ornamented with epidermal fringes ; a foot and operculum; and the head has long delicate tentacula, and very distinct black eyes. The development of the pulmoniferous embryo is best seen in the transparent eggs of the fresh-water limneids; these are not hatched until the young have passed the larval condition, and their ciliated head-lobes (or veil) are superseded by the creeping disk, or foot. * Fig. 67. Fry of Eolss (from Alder and Hancock). 0, the operculum; the original is not larger than the letter o. 7 Fig. 68. Paludina vivipara, L. (original); the internal organs are represented as if seen through the shell. The ovary, distended with eggs and embryos, occupies the right side of the body whorl; the gill is seen on the left; and between them the termination of the alimentary canal. Surrey Docks, June, 18%. 204 MANUAL OF THE MOLLUSCA. The development of the air-breathers goes on within the shell, and has been traced by Van Beneden, Gegenbaur, and others in Limax, Veronicella, Vitrina, Bulimus, and Helix, The shell of the gasteropods is usually spiral, and univalye ; more rarely tubular, or conical, and in one genus it is multivalve. The following are its principal modifications :— A. Regularly spiral, a. elongated or turreted; terebra, turritella. b. cylindrical; megaspira, pupa. c. short; buccinwm. d. globular; natica, helix. e. depressed ; solarium. J. discoidal ; planorbis. g. convolute; aperture as long as the shell; cyprea, Eulla. h. fusiform ; tapering to each end, like fusus. i. trochiform ; conical, with a flat base, like trochus. k. tarbinated ; conical, with a round base, like turbo. l. few-whorled ; Helix hemastoma. Pl. XII., Fig. 1. m. many-whorled ; Helix polygyrata. Pl. XII, Fig. 2. mn. ear-shaped; haliotis. B. Irregularly spiral; siliquaria, vermetus. C. Tubular; dentaliwm. Dp. Shield-shaped ; umbrella, parmophorus. E. Boat-shaped; navicella. F. Conical or limpet-shaped ; patella. G. Multivalye and imbricated; chiton. The only symmetrical shells are those of carinaria, atlanta, dentalium, and the limpets.* Nearly all the spiral shells are dextral, or right-handed; a few are constantly sinistral, like clausilia ; reversed varieties of many shells, both dextral and sinistral, have been met with. The cayity of the shell is a single conical or spiral chamber; — no gasteropod has a multilocular shell like the nautilus, but spurious chambers are formed by particular species, such as — Triton corrugatus (Fig. 69), and Huomphalus pentangulatus ; or under special circumstances, as when the upper part of the spire is destroyed. Some spiral shells are complete tubes, with the whorls sepa- rate, or scarcely in contact, as scalaria, cyclostoma, and valvata ; * The curve of the spiral shells and their opercula and also of the Nautilus, is a logarithmic spiral; so that to each particular species may be annexed*a number indicating the ratio of the geometrical progression of the dimensions of its whorls Rev. H. Moseley, “On geometrical Forms of Turbinated and Discoid Shells.”—Phi, Trans, Lond. 1838. Pt. 2, p. 351, GASTEROPODA. 205 but more commonly the inner side of the spiral tube is formed by the pre-existing whorls (Fig. 69). The axis of the shell, around which the whorls are coiled, is sometimes open or hollow; in which case the shell is said to be perforated, or wmbilicated (e.g. solarium). The perforation may be a mere chink, or fissure (rima), as in lacuna; or it may be filled up by a shelly deposit, as in many naticas. In other shells, like the triton, the whorls are closely coiled, leaving only a pillar of shell, or colwmella, in the centre: such shells are said to Le imperforate. apex. outer lip of the aperture. anterior canal. Fig. 69. Section of aspiral univalve.* The apex of the shell presents important characters, as it was the nucleus or part formed in the egg; it is sinistral in the pyramidellide, oblique and spiral in the nucleobranchs and emarginule, and mammillated in Turbinella a el and Fusus antiquus. The apex is directed backwards in all except some of the patellide, in which it is turned forwards, over the animal’s head. * Fig. 69. Longitudinal section of Triton corrugatus, Lam., from a specimen in the cabinet of Mr. Gray, The upper part of the spire has been partitioned off many times successively, 906 MANUAL OF THE MOLLUSCA. In the adult condition of some shells the apex is always truncated (or decollated) as in cylindrella and Bulimus decollatus ; in others it is only truncated when the animals have lived in acidulous waters (e.g. cerithidea and pirena), and specimens may be obtained from more fayourable situations with the points perfect. The line of channel formed by the junction of the whorls is termed the suture. The last turn of the shell, or body-whorl, is usually very capacious ; in the females of some species the whorls enlarge more rapidly than in the males (e.g. Buccinum undatum). The ‘base’? of the shell is the opposite end to the apex, and is usually the front of the aperture. The aperture is entire in most of the vegetable feeders (holos- tomata), but notched or produced into a canal, in the carniyorous families (sighonostomata) ; this canal, or siphon, is respiratory in its office, and does not necessarily indicate the nature of the food. Sometimes there is a posterior channel or canal, which is excurrent, or anal, in its function (e.g. strombide and ovulum volva) ; 1t is represented by the slit in scisswrella, the tube of typhis, the perforation in fissuwrella, and the series of holes in haliotis. The margin of the aperture is termed the peristome; sometimes it is continuous (cyclostoma), or becomes continuous in the adult (carocolla) ; very frequently it is ‘‘ interrupted,” the left side of the aperture being formed only by the body-whorl. The right side of the aperture is formed by the outer lip (/abrum), the left side by the inner or columellar lip (/abiwm), or partly by the body-whorl (termed the ‘‘wall of the aperture,” by Pfeiffer). The outer lip is usually thin and sharp in immature shells, and in some adults (e.g. helicella and bulimulus) ; but more frequently it is thickened ; or reflected; or curled inwards (inflected), as in cyprea ; or expanded, as in pferoceras ; or fringed with spines, as in murex. When these fringes or expansions of the outer lip are formed periodically, they are termed varices. Lines of colour, or sculpture, running from the apex to the aperture are spiral or longitudinal, and others which coincide with the lines of growth are ‘‘ transverse,” as regards the whorls; but stripes of colour extending from the apex across the whorls are often described as ‘“‘longitudinal” or ‘‘radiating,” with respect to the entire shell. Shells which are always concealed by the mantle are colourless, like limaw and parmophorus ; and those which are covered by the — GASTEROPODA. 207 mantle-lobes when the animal expands, acquire a glazed or enamelled surface, like the cowries; when the shell is deeply immersed in the foot of the animal it becomes partly glazed, as in cymba. In all other shells there is an epidermis, although it is sometimes very thin and transparent. In the interior of the shell the muscular impression is horse- shoe shaped, or divided into two scars; the horns of the crescent are turned towards the head of the animal. The operculum with which many of the gasteropods close the aperture of their shells, presents modifications of structure which are so characteristic of the sub-genera as to be worthy of particular notice. It consists of a horny layer, sometimes strengthened by the addition of calcareous matter on its exterior, and in its mode of growth it presents some resemblance to the shell itself. Its inner surface is marked by a muscular scar, whose lines bear na relation to the external lines of growth, and its form is unlike the muscular scar in the shell. It is developed in the embryo, within the ege, and the point from which it commences is termed the nucleus; many of the spiral and concentric forms fit the aperture of the shell with accuracy, the others only close the entrance partially, and in many genera, especially those with large apertures (e.g. dolium, cassidaria, harpa, navicella), it is quite rudimentary or obsolete. Fig. 70. The operculum is described as— Concentric, when it increases equally all round, and the nucleus is central or sub-central, as in paludina and ampullaria (Pl. IX., Fig. 26). Imbricated, or lamellar (Fig. 71), when it grows only on one side, and the nucleus is marginal, as in purpura, phorus, and paludomus. Claw-shaped, or unguiculate (Fig. 70), with the nucleus apical or in front, as in turbinella and fusus; it is claw-shaped and serrated in strombus (Fig. 76). Spiral, when it grows only on one edge, and reyolyes as it grows ; it is always sinistral in dextral shells. Paucispirai, or few-whorled (Fig. 73), as in littorina. 208 MANUAL OF THE MOLLUSCA. Sub-spiral, or scarcely spiral, in melania (Pl. VIII., Fig. 25*). Multispiral, or many-whorled (Fig. 72), as in trochus, where they sometimes amount to twenty; the number of turns which the operculum makes is not determined by the number of whorls in the shell, but by the curvature of the opening, and the neces- sity that the operculum should revolve fast enough to fit it constantly. (Moseley.) It is said to be articulated when it has a projection, asin nerita (Fig. 74). Too much importance, howeyer, must not be attached to this very variable plate, as an aid to classification ; it is present in some species of voluta, oliva, conus, mitra, and cancellaria, but absent in others; it is (indifferently) horny or shelly in the species of ampullaria and natica ; in paludina it is concentric, in paludomus lamellar, in valvata spiral ; in solariwm and cerithium, it is multispiral or paucispiral. The researches of Dr. Lovén* haye led to many attempts being made to remodel the arrangement of the G‘asteropoda by the aid of peculiarities in their dentition. "Whatever improvements may be thus obtained, it does not appear desirable to introduce a new terminology for divisions long since well cial and already over-burdened with classical names.t The patterns, or types of lingual dentition, are on the whole remarkably constant; but their 2 systematic value is not uniform. It must be remembered that the teeth are essentially epithelian cells, and like other superficial organs lable to be modified in accordance with the wants and habits of the creatures. ~The instruments with which animals obtain their food are of all others most subject to these adaptive modifications, and can neyer form the basis of a philosophical system.t * Gfversigt af Kongl. Vetensk. Akad. Férhandl. 1847, + The following names were proposed by Troschel (in Wiegman’s Handbuch der Zoologie, 1848) and Gray (An. Nat. Hist.) for the principal types of lingua] dentition :— a. Tzenioglossa, teeth 3. 1. 3; Littorina, Natica, Triton. 6. Toxoglossa, teeth 1. 0. 1; Conus, Terebra? c. Hamiglossa, teeth 1.1. 1; Murex, Buccinum. d. Rachiglossa, teeth 0. 1.0; Voluta, Mitra? e. Gymnoglossa, teeth 0; Pyramidella, Cancellaria, Solarium? f. Rhipidoglossa, teeth 00, 1.00; Nerita, Trochus. ¢ The carnivorous opossums have teeth adapted for eating flesh, but are not on that account to be classified with the placental carnivora. The lingual teeth, like the operculum, usually have a structure characteristic of the genera or sub-genera. Some- times they have a general uniform character throughout a whole family or group of families. In many cases they present minute differences which promise to be valuable aids for distinguishing closely allied species. For example, Patella athletica may be distinguished from the common limpet (P, vulgata) by its teeth. \. oe eel 6 GASTEROPODA. 209 Some of the gasteropoda can suspend themselves by glutinous threads, like litiopa and Rissoa parva, which anchor themselves to sea-weeds (Gray), and cerithidae (Fig. 75), which frequeutly leaves its proper element, and is found hanging in the air. (Adams.) A /, West India land-snail (cyclostoma suspensum) ‘ also suspends itself. (Guilding.) The origin of these threads has not been explained; but some of the limaces lower themselves to the ground by a thread which is not secreted by any particular gland, but derived from the exudation over the general surface of the body. (Lister, D’Orbigny.) The division of this extensive class into orders and families has engaged the attention of many naturalists, and a variety of methods haye been proposed. Cuvier’s classification was Fig. 75. the first that possessed much merit, and several of his orders haye since been united with advantage. System of Cuvier. System now adopted. “lass. GASTEROPODA. Order 1. Pectinibranchiata = 2 ee Ord. Prosobranchiata, M. Edw. 4, Tubulibranchiata 5. Pulmonata Ord. Pulmonifera. 6. Tectibranchiata ) 7. Inferobranchiata i Ord. Opisthobranchiata, M. Edw. 8. Nudibranchiata. Class. HETEROPODA. Ord. Nucleobranchiata, Bl. ORDER I. PROSOBRANCHIATA. Abdomen well developed and protected by a shell, into which the whole animal can usually retire. Mantle forming a vaulted chamber over the back of the head, in which are placed the excretory orifices, and in which the branchiz are almost always lodged. Branchie pectinated, or plume-like, situated (proson) in advance of the heart. Sewes distinct. (M. Edwards.) SEoTIon A. SrpPHONOSTOMATA. Carnivorous Gasteropods. Shell spiral, usually imperforate; aperture notched or produced into a canal in front. Operculum horny, lamellar. 210 MANUAL OF THE MOLLUSCA. Animal provided with a retractile proboscis ; eye-pedicels con - nate with the tentacles ; margin of the mantle prolonged into a siphon, by which water is conveyed into the branchiul chamber ; gills one or two, comb-like, placed obliquely over the back. Species all marine. FAMILY I.—StTRomMBIDzZ. Wing-shells. Shell with an expanded lip, deeply notched near the canal. Operculum claw-shaped, serrated on the outer edge. Animal furnished with large eyes, placed on thick pedicels; tentacles slender, rising from the middle of the eye-pedicels. Foot narrow, ill-adapted for creeping. Lingual teeth single ; uncini, three on each side. The strombs are carrion feeders, and, for molluscous animals, very active; they progress by a sort of leaping movement, turn- ing their heavy shell from side to side. Their eyes are more perfect than those of the other gasteropods, or of many fishes. ti : ° Ss \ _ =» Dx aN Xi ne SSS ee ( Fig. 76.* Stromsvs, L. Stromb. Ltymology, strombos, a top. Type, 8. pugilis (Pl. IV., Fig. 1). Shell rather ventricose, tubercular or spiny; spire short; aperture long, with a short canal above and truncated below; outer lip expanded, lobed above, and sinuated near the notch of # Fig. 76. Strombus auris- Diana, L. (after Quoy and Gaimard), Amboyna. 7, pro- boscis, between the eye-pedicels ; 7, foot, folded up; 0, operculum; m, border of the tmaantle; s, respiratory siphon. GASTEROPODA. 211 the anterior canal. Lingual teeth (S. floridus) 7 cusped ; uncini, 1 tri-dentate, 2, 3 claw-shaped, simple (Fig. 77).* Fig. 77. Strombus. (Wilton). Strombus (floridus) is described by Lovén as haying a non- retractile, produced muzzle, like Aporrhais. 8. gibberulus is represented by Dr. Bergh with all the uncini denticulated. Distribution, 65 species. West Indies, Mediterranean, Red Sea, India, Mauritius, China, New Zealand, Pacific, West America. On reefs, at low water, and ranging to 10 fathoms. Fossil, 5 cretaceous species; 38 species Miocene—. South Europe. There is a group of small shells in the eocene tertiary strata of England and France, nearly related to the living S. fissurellus, L., some of which have been placed with rostel- laria, because the notch in the outer lip is small or obsolete. They probably constitute a sub-genus, to which the name Rimella Ag., might be applied. Hxample, 8. Bartonensis. Pl. iV Bie.:2. The fountain-shell of the West Indies, S. gigas, I., is one of the largest living shells, weighing sometimes four or five pounds; its apex and spines are filled up with solid shell as it becomes old. Immense quantities are annually imported from the Bahamas for the manufacture of cameos, and for the porcelain works; 300,000 were brought to Liverpool alone in the year 1850. (Mr. Archer.) PTEROCERAS, Lam. Scorpion shell. Etymology, pteron, a wing, and ceras, a horn. Type, P. lambis. Pl. LY., Fig. 3. Shell like strombus when young; outer lip of the adult pro- duced into several long claws, one of them close to the spire, and forming a posterior canal. Distribution, 12 species. India, China. * The lingual dentition of strombus resembles that of aporrhazs, and is unlike that of the whelks; but it is more probable that aporrhais is the representative of strombus than that it is very closely allied. 912 MANUAL OF THE MOLLUSCA. Fossil, nearly 100 species are enumerated by D’Orbigny, ranging from the lias to the upper chalk; many of them are more nearly related to aporrhais (cerithiade). ROsTELLARIA, Lam. Litymology, rostellum, a little beak. Synonym, Fusus, Humphreys. Hxample, R. curta. Pl. IV., Fig. 4. Shell with an elongated spire; whorls numerous, flat; canals long, the posterior one running up the spire; outer lip more or less expanded, with only one sinus, and that close to the beak. Distribution, 8 species. Red Sea, India, Borneo, China. Range, 30 fathoms. Fossil, 80 species. Neocomian—chalk (= aporrhais?). 6 species. Eocene—. Britain, France, &c. The old tertiary species have the outer lip enormously ex- panded, and smooth-edged; they constitute the section hippo- chrenes of Montfort (e.g., Rost. ampla, Solander. London clay). Sub-genus ? Spinigera, D’Orbigny. 1847. Shell like rostel. laria ; whorls keeled ; keel developed into a slender spine on the outer lip, and two on each whorl, forming lateral fringes, as in ranella. Fossil, 5 species. Inf. oolite—chalk. Britain, France. SERAPHS, Montfort. (Terebellum, Lam.) Etymology, diminutive of terebra, an auger. Shell smooth, sub-cylindrical; spire short or none; aperture long and narrow, truncated below; outer lip thin. Distribution, 1 species. China. Philippines, 8 fathoms. (Cuming.) Fossil, 5 species. Eocene—. London, Paris. The animal of terebellwm has an operculum like strombus ; its eye-pedicels are simple, without tentacles. (Adams.) In one fossil species, Z', fusiforme, there is a short posterior canal, as in rostellaria, Famizty I1.—MUvRIcIDz, Shell with a straight anterior canal; aperture entire behind. Animal with a broad foot; eyes sessile on the tentacles, or at their base; branchial plumes two. Lingual ribbon long, linear ; rachis armed with a single series of dentated teeth; wncini, single. Predatory on other mollusca. The two species belong- ing to the genus Cheletropis, Forbes =Sinusigera, D’Orbigny, GASTEROPODA, 213 are now known to have no affinity with the Atlantida, but to be the larya form of species belonging to the Muricide. Fig. 78. Murex tenuispina. (Wilton.) MovreEx (Pliny), L. Types, M. palma-rose, Pl. IV., Fig. 10. M. tenuispina, Pl. CV., Fig. 9. M. haustellum, Pl. IV., Fig. 8. M. radix, oinnatus. Shell ornamented with three or more continuous longitudinal - varices ; aperture rounded ; beak often very long; canal partly closed; operculum concentric, nucleus sup-apical (Pl. IV., Fig. 10); lingual dentition (M. erinaceus), teeth single, three crested ; uncini single, curved. For dentition of MW. tenuispina see Fig. 78. Distribution, 220 species. World-wide; most abundant on the West Coast of tropical America, in the Chinese Sea, West Coast of Africa, West Indies; ranging from low water to 25 fathoms, rarely at 60 fathoms. Fossil, 164 species. Eocene—. Britain, France, Jaya, &e. A few of the species usually referred to this genus belong to pisania and trophon. The murices appear to form cnly one-third of a whorl annually, ending in a varix; some species form intermediate varices of less extent. M. erinaceus, a very abundant species on the coasts of the channel, is called ‘‘ sting-winkle” by fisher- men, who say it makes round holes in the other shell-fish with its beak. (See p. 21.) The ancients obtained their purple dye from species of mwrex ; the small shells were bruised in mortars, the animals of the larger ones taken out. (EF. Col.) Heaps of broken shells of the M. trunculus and caldron-shaped holes in the rocks may still be seen on the Tyrian shore. (Wilde.) On the coast of the Morea there is similar evidence of the employ- ment of MM. brandaris for the same purpose. (M. Boblaye.) Typuis, Montfort. Etymology, typhos, smoke. 214 MANUAL OF THE MOLLUSCA. Type, T. pungens. Pl. IV., Fig. 11. Shell Lke murex; but having “tubular spines between the varices, ot which the last is open, and occupied by the excurrent canal. Distribution, 9 species. Mediterranean, West Africa, Cape, India, Western America. —d0 fathoms. Fossil, 8 species. Eocene—. London, Paris. PISANIA, Bivon, 1832. Etymology, a native of (the coast near) Pisa, in Tuscany. Synonyms, Pollia, Enzina, and Euthria (Gray). Types, P. maculosa. Pl. IV., Fig. 14 (Knzina), zonata, Pl. IW, s,s 15. Shell with numerous indistinct varices, or smooth and spirally striated ; canal short; inner lip wrinkled ; outer lip crenulated. Operculum ovate, acute; nucleus apical. The pisanie have been usually confounded with buccinum, murex, and ricinula. _ Distribution, about 120 species. West Indies, Africa, India, Philippines, South Seas, Western America. Fossil, P species. Hocene—Britain, France, &c. RANELLA, Lam. Frog-shell. Synonym, Apollon (Montfort and Gray). Types, R. granifera. Pl. IV., Fig. 12. RK. spimosa, Shell with two rows of continuous varices, one on each side. Operculum ovate, nucleus lateral. Distribution, 58 species. Mediterranean, Cape, India, China, Australia, Pacific, Western America. ange, low-water to 20 fathoms. Fossil, 23 species. Hocene—. TRITON, Lam. Etymology, Triton, a sea-deity. Synonym, Persona (Montfort, Gray). Type, T. tritonis, L. species. Pl. LV., Fig. 13._ Shell with disconnected varices; canal prominent; lips denti- culated. Operculum ovate, sub-concentric. Distribution, 100 species. West Indies, Mediterranean, Africa, India, China, Pacific, Western America. Ranging from GASTEROPODA. OES low water to 10 or 20 fathoms; one minute species has been dredged at 50 fathoms. Fig. 79. One of the buccal plates of Triton, 4% (Wilton.) Fossil, 45 species. Eocene—. Britain, France, &c. Chili. The great triton (J. tritonis) is the conch blown by the Australian and Polynesian Islanders. A very similar species (7. nodiferus) is found in the Mediterranean, and a third in the Fig. 80. Teeth of Triton, 249. (Wilton.) West Indies. The buccal plates and teeth of Triton are shown in Figs. 79, 80. FASCIOLARIA, Lam. Etymology, fasciola, a band. Type, F. tulipa. Pl. V., Fig. 1. Shell fusiform, elongated ; whorls round or angular; canal open; columellar lip tortuous, with several oblique folds. Operculum claw- shaped. . gigantea of the South Seas attains a length of nearly two 'g-&l. fue Tarentint. feet. The teoth of Fasciolaria re- ea ge semble those of Fusus Islandicus. In Buccinum undatum, the median tooth has fivé, or rarely six denticles; and Mr. Wilton 216 MANUAL OF THE MOLLUSCA. has observed that B. limbosum, ¢ has the teeth seven cusped, while in the females they are six cusped. Distribution, 108 species. West Indies, Mediterranean, West Africa, India, Australia, South Pacific, Western America. Fossil, 30 species, U. chalk—. France. TURBINELLA, Lam. Etymology, diminutive of turbo, a top. Type, T. pyri. Pi x., Kis. 2: Shell thick; spire short; columella with several transyers¢ folds. Operculum claw-shaped. Fig. 70. The chank-shell (7. pyrum) is carved by the Cingalese, and reversed varieties of it, from which the priests administer medicine, are held sacred. Distribution, 70 species. West Indies, South America, Africa, Ceylon, Philippines, Pacific, Western America. Fossil, 20 species. Miocene—. Sub-genera, Cynodonta (Schum.), T. cornigera. Pl. V., Fig. 3. Latirus (Montfort), T. gilbula. Pl. V., Fig. 4. Lagena (Schum.), T. Smaragdula, L. species. Northern Australia. CANCELLARIA, Lam. Etymology, cancellatus, cross-barred. Type, C. reticulata. Pl. V., Fig. 5. Shell cancellated ; aperture chanelled in front; columella with several strong oblique folds; no operculum. The animals are vegetable feeders. (Desh.)* oe anata lite Distribution, 71 species. West Indies, Mediterranean, West 7 Africa, India, China, California. Fossil, 60 species. Up. Chalk—. Britain, France, &c. Admete (viridula) is a boreal form of Cancellaria, without — plaits. DIBAPHUS, Phi. Synonym, conohelix edentulus. (Sw.) Shell subcylindrical, — spire acute; aperture narrow, linear, edentulous, excised at tho | base; lip thickened, rectilinear, rounded and abbreviated below. | TRIcHOTROPIS, Broderip, 1829. Etymology, Thrix (trichos), hair, and tropis, keel. Type, T. borealis, Pl. VI., Fig. 8. (=? Admete, Phil., no : operculum), * Canceliaria and trichotroprs form a sms}i naturalfamily connected with cerithiala and strombide. GASTEROPODA. DA | Sheil thin, umbilicated ; spirally furrowed ; the ridges with epidermal fringes; columella obliquely truncated; operculum lamellar, nucleus external. Animal with a short broad head; tentacles distant, with eyes on the middle; proboscis long, retractile. Lingual dentition similar to velutina; teeth single, hamate, denticulated ; wncini 3: 1 denticulate, 2 and 3 simple (Fig. 82). Fig. 82. Trichotropis borealis. (Warrington). Loyén places Trichotropis in the same family with Velutina ; Cancellaria is very closely allied, though it- wants both teeth and operculum. Mr. Couthouy describes Trichotropis cancellata as haying a muzzle like Littorina. Distribution, 14 species. Northern seas. United States, Green- land, Melville Island, Behring’s Straits, North Britain. 15—80 fathoms. 1 species from Japanese seas (A. Adams). Fossil, 1 species. Miocene—. Britain. Pyrvuua, Lam. Fig-shell. Etymology, diminutive of pyrus, a pear. Synonyms, Ficula, Sw. Sycotypus, Br., Cassidula, Humph. Cochlidium, Gray. fype, P.ficus. Pl. Y., Fig. 6. Shell pear-shaped; spire short; outer lip thin; columella smooth; canal long, open. No operculum in the typical species. Distribution, 39 species. West Indies, Ceylon, Australia, China, Western America. Fossil, 32 species. Neocomian—. Europe, India, Chili, Java. Pyrula ficus has a broad foot, truncated and horned in front ; the mantle forms lobes on the sides, which nearly meet over the back of the shell. Chinese seas, in 17—35 fathoms water. (Adams. ) Sub-genera, Fulgur, Montfort P. peryersa. (= Pyrella, Sw. P. spirillus.) Rapana, Schum. P. bezoar, shell perforated. Operculum lamellar, nucleus external. This nppears to be a Purpura. Myristica. Sw. P. melongena. Pl. V., Fig. 7. Operculum pointed, curved. L 218 MANUAL OF THE MOLLUSCA. Fusus, Lam. Spindle-shell. Synonyms, Colus, Humph. Leiestoma (bulbiformis). Sw. Strepsidura, Sw. #ype, ¥. cous.” Pl. V., Pie. 8. Shell fusiform; spire many-whorled; canal straight, long; operculum ovate, curved, nucleus apical. Pl. V., Fig. 9*. Distribution, 184 species. World-wide. The typical species are sub-tropical. Australia, New Zealand, China, Senegal, United States, Western America, Pacific. Fossil, 320 species. Bath oolite? Gault—Eocene—. Britain, &c. Sub-genera, Trophon, Montfort. TF’. magellanicus, Pl. IV., Fig. 16. 38 species. Antarctic and Northern seas. British coast. 5—70 fathoms. Jossil, Chili, Britain. Clavella, Sw. (Cyrtulus, Hinds), body-whorl ventricose, sud- denly contracted in front ; canal long and straight. Resembling a turbinella, without plaits. 2 species. Marquesas, Panama. Fossil, Kocene. I’. longzevus (Solander), Barton, &c. Chrysodomus, Sw. FE. antiquus (var.). Pl. V., Fig. 9. Canal short; apex papillary; lingual dentition like buccinum, 12 species. Spitzbergen, Davis’s Straits, Britain, Mediterranean, Kamtschatka, Oregon. Low-water to 100 fathoms. Fossil, Pliocene. Britain, Sicily. Pusionella, Gray. F. pusio, L. species (= F. nifat, Lam.), columella keeled. Operculum, nucleus internal. 7 species; Africa, India. Fossil, Tertiary. France. Fusus colosseus and proboscidalis, Lam., are two of the largest living gasteropods. Fusus (chrysodomus) antiquus, called the red-whelk on the coasts of the Channel, and ‘‘ buckie”’ in Scotland, is extensively dredged for the markets, being more esteemed than the buccinum. It is the ‘“‘roaring buckie,” in which the sound of the sea may always be heard. In the Zetland cottages it is suspended horizontally, and used for a lamp; the cavity containing the oil, and the canal the wick. {Fleming.) The reversed variety (F. contrarius, Sby.) is found in the Mediterranean, and on the coast of Spain; it abounds in the pliocene tertiary (crag) of Essex. The fusus deformis, a similar species, found off Spitzbergen, is always reversed. Famity ITI.—Bucornip&. Shell notched in front; or with the canal abruptly reflected, producing a kind of varix on the front of the shell. Animal similar to murex; lingual ribbon long and linear a GASTEROPODA. 219 \Fig. 16), rachidian teeth single, transverse, dentated in front ; uncini single. Carnivorous. Buccinum, L. Whelk. Etymology, buccina, a trumpet, or triton’s-shell. Type, B. undatum. Pl. V., Fig. 10. Shell few whorled; whorls ventricose; aperture large; canal very short, reflected; operculum lamellar, nucleus external. (See Pisania.) Distribution, 48 species. Northern and Antarctic seas. Low water to 100 fathoms. (Forbes.) (B.? clathratum, 136 fathoms, off Cape). South Australia. Fossil, 130 species, including Pisania, &c. Gault ?—Miocene— Britain, France. Fig. 83. Nidamental capsules of the Whelk.* The whelk is dredged for the market, or used as bait by fishermen; it may be taken in baskets, baited with dead fish. Its nidamental capsules are aggregated in roundish masses, which when thrown ashore, and drifted by the wind resemble corallines. Each capsule contains five or six young, which, when hatched, are like Fig. 83, b: a represents the inner side of a single capsule, showing the round hole from which the fry have escaped. Sub-genus, Cominella, Gray. Ez. B. limbosum, purpura maculosa, &c. Operculum asin fusus. About 12 species. PSEUDOLIVA, Swainson. Etymology, named from its resemblance to oliva, in form. Synonyms, Sulco-buccinum, D’Orbigny. Gastridium (Gray) G. Sowerby. * Fig. 83, From a small specimen, on an oyster-shell, in the cabinet of Albany Han cock, Esq. The line at d represents the length of the young shell, ne 920 MANUAL OF THE MOLLUSCA. / Type, P. plumbea. Pl. V., Fig. 12. Shell globular, thick; with a deep spiral furrow near the front of the body-whorl, forming, as in monoceros, a small tooth on the outer lip; spire short, acute; suture channelled; inner lip callous; aperture notched in front; operculum? Animal unknown. Distribution, 6 species. Africa and California. Fossil, 5 species. Eocene. Britain, France, Chili. P ANOLAX (Roissy), Conrad, Lea. Etymology, an aulax, without furrow. Synonyms, Buccinanops, D’Orbigny. Leiodomus, Sw. Bullia, Gray. Types, A. gigantea, Lea. Buc. levigatum. B. semiplicata, PL V., Fig: 14. Shell variable ; like buccinum, pseudoliya, or terebra; sutures enamelled ; inner lip callous. Animal without eyes; foot very broad; tentacles long an¢ slender; operculum pointed, nucleus apical. Distribution 26 species. Brazil, West Africa, Ceylon, Pacific Western America. Fossil, 8 species. Eocene—. North America, France. ? HALIA, Risso. Etymology, halios, marine. Synonym, Priamus, Beck. Types, bulla helicoides (Brocchi). Miocene, Italy. Helix priamus (Meuschen). Coast of Guinea ? Shell like achatina ; ventricose, smooth ; apex regular, obtuse, operculum? ‘The fossil species occurs with marine shells, and sometimes coated by a polyzoon (lepralia). TEREBRA, Lamarck. Auger-shell. Synonyms, Acus, Humph. Subula, Bl. Dorsanum, Gray. Type, T. maculata. Pl. Y., Fig. 13. Shell long, pointed, many-whorled; aperture small ; | canal short ; operculum pointed, nucleus apical. Animal blind, or with eyes near the summit of minute tentacles. Distribution, 109 species, mostly tropical. Mediterranean (1 species). India, China, Western America. Foesil, 24 species. Eocene—. Britain, France, Chili. fe eee GASTEROPODA. oa EBuRNA, Lamarck. Ivory-shell. Etymology, ebur, ivory. Synonym, Latrunculus, Gray. Type, Ei. spirata. Pl. V., Fig. 11. Shell umbilicated when young; inner lip callous, spreading and covering the umbilicus of the adult; operculum pointed. nucleus apical. Distribution, 9 species. Red Sea, India, Cape, Japan, China, Australia. Solid, smooth shells, which haye usually lost their epidermis, and are pure white, spotted with dark red; the animal is spotted like the shell. 14 fathoms. (Adams.) Nassa, Lam. Dog-whelk. Etymology, nassa, a basket used for catching fish. Synonyms, Desmoulinsia and Northia, Gray. Type, N. arcularia. Pl. V., Fig. 15. Shell like buccinum; columellar lip callous, expanded, form- | ing a tooth-like projection near the anterior canal. Operculum ovate, nucleus apical. Lingual teeth arched, pectinated ; uncini, with a basal tooth. The animal has a broad foot, with diverging horns in front, and two little tails behind. J. obsoleta (Say) lives within the influence of fresh water and becomes eroded. WN. reticulata, L., is common on the English shores at low water, and is called the dog-whelk by fishermen. Distribution, 210 species. Low water—d0 fathoms. World- wide. Arctic, Tropical, and Antarctic Seas. Fossil, 19 species. Eocene—. Britain, &c. North America. Sub-genus, Cyllene, Gray. CO. Oweni, Pl. V., Fig. 17. Outer lip with a slight sinus near the canal; sutures channelled. West Africa, Sooloo Islands, Borneo. Fossil, Miocene, Touraine. Cyclonassa, Swainson. OC. neritea, Pl. V., Fig. 16. PuHos, Montfort. Etymology, phos, light. Synonym, Rhinodomus, Sw. Type, P. senticosus, Pl. V., Fig. 18. Shell like nassa; cancellated ; outer lip striated internally, with a slight sinus near the canal; columella obliquely grooved. The animal has slender tentacles, with the eyes near their tips. Distribution, 30 species. (Cuming.) Red Sea, Ceylon, Philip- pines, Australia, West America. 222 MANUAL OF THE MOLLUSCA. ? Rrneloua, Deshayes. Etymology, diminutive of ringens, from ringo, to grin. Type, R. ringens, Pl. V., Fig. 21. Shell minute, ventricose, with a small spire; aperture notched, rolumella callous, deeply plaited; outer lip thickened and feflected. Distribution, 7 species? Mediterranean, India, Philippines, Gallapagos. Fossil, 9 species. Miocene—. Britain, France. Ringicula is placed with nassa by Dr. Gray and Mr. 8. Wood; it appears to us very nearly allied to cinulia = avellana, D’Orbigny) ip tornatellide. PuRPURA (Adans.), Lam. Purple. Type, P. persica, Pl. VI., Fig. 1. | Shell striated, imbricated, or tuberculated; spire short; © aperture large, slightly notched in front; upper lip much worn and flattened. Operculum lamellar, nucleus external. Pl. VL., Fig. 2. Lingual dentition like murex erinaceus; teeth trans- verse, three crested; uncini small, simple. Many of the purpure produce a fluid which gives a dull — crimson dye; it may be obtained by pressing on the operculum. ~ P. lapilius abounds on the British coast at low water, amongst — sea-weed; it is very destructive to mussel-beds. (Fleming.) Distribution, 140 species. West Indies, Britain, Africa, India, — New Zealand, Pacific, Chili, California, Kamtschatka. From s low water—25 fathoms. Fessil, 40 species. Tertiary—. Britain, France, &c. . Concholepas, Fayan. CO. lepas (Gmelin species) Pl. VI., Fig. 3. © Peru. The only species differs from purpura in the size of its aperture and smallness of the spire. i Cuma (Humphrey) P. angulifera, inner lip with a single ] prominent fold. ? PURPURINA (Lycett, 1847), D’Orbigny. Shell ventricose, coronated; spire short; aperture large, | scarcely notched in front. Fossil, 9 species. Bath-oolite. Britain, France. The type — P. rugosa, somewhat resembles purpura chocolatum (Duclos), but — the genus probably belongs to an extinct group. RHIZOCHILUS, Stp. 1850. Example, R.antipathum. Founded on a species of Purpura? GASTEROPODA. 223 which lives on the antipathes ericoides. When adult they attach themselves, singly or in groups, to the branches of the coral, or to each other, by a solid extension of the lips of the shell. The aperture becomes closed, with the exception of the respiratory canal. ‘ MonoceEros, Lam. Etymology, monos, one; ceras, a horn. Synonyms, Acanthina, Fischer. Chorus, Gray. Type, M. imbricatum. Pl. VI., Fig. 4. (Buc. monoceros, Chemn.) Shell like purpura; with a spiral groove on the whorls, end- ing in a prominent spine on the outer lip. This genus is retained on account of its geographical curiosity ; it consists of species of purpura, lagena, turbinella, pseudoliva, &e. Distribution, 18 species. West coast of America. fossil, Tertiary. Chili. M. giganteus (chorus) has the canal produced like fusus. J. cingulatum is a turbinella, and several species belong more pro- perly to lagena. PEDICULARIA, Swainson. Type, P. sicula. Pl. VI., Fig. 5. (Thyreus, Phil.) Shell very small, limpet-like; with a large aperture, channelled in front, and a minute, lateral spire. Lingual dentition peculiar ; teeth single, hooked, denticulated ; wncini, 3; 1 four-cusped, 2, 3, elongated, three-spined. Distribution, 1 species. Sicily, adhering to corals. Closely allied to purpura madreporarum, Sby. Chinese Sea. RICINULA, Lam. Ktymology, diminutive of ricinus, the (fruit of the) castor-oil plant. _ Example, R. arachnoides. Pl. VI., Fig. 9 (= murex ricinus, L.). Shell thick, tuberculated, or spiny; aperture contracted by callous projections on the lips. Operculum as in purpura. Distribution, 34 species. India, China, Philippines, Australia, Pacific. fossil, 3 species. Miocene—. Trance, PLANAX18, Lam. Type, P. sulcata. Pl. VI., Fig. 6. Synonyms, Quoyia and Leucostoma. Shell, turbinated ; aperture notched in front; mner lip callous, 924 MANUAL OF THE MOLLUSCA. channelled behind; operculum subspiral (quoyia) or semi-ovate. BNL His. 7. Distribution, 27 species. "West Indies, Red Sea, Bourbon, India, Pacific, and Peru. Fossil, Miocene ? Small coast shells, resembling periwinkles, with whick Lamarck placed them. This genus is now generally placed among the Littorinide. Macitvus, Montfort, 1810. Synonyms, Campulote, Guettard, 1759. Leptoconchus, Rippell. Type, M. antiquus. Pl. V., Figs. 19, 20. Shell, when young, spiral, thin ; aperture channelled in front ; adult, prolonged into an irregular tube, solid behind; operculum lamellar. Distribution, 4 species.. Red Sea, Mauritius. The magili live fixed amongst corals, and grow upwards with the growth of the zoophytes in which they become immersed ; they fill the cavity of the tube with solid shell as they advance. Cassis, Lam. Helmet-shell. Synonyms, Bezoardica, Schum. Leyenia, Gray. Cypreecassis, Stutch. Type, C. flammea. Pl. VI., Fig. 14. Shell yentricose, with irregular varices; spire short ; aperture long, outer lip reflected, denticu- lated; inner lip spread over the body-whorl ; canal sharply recurved. Operculum small, elon- gated; nucleus in the middle of the straight inner edge (Fig. 84). Lingual teeth 3, 1, 3, as in Fig. 85. The spiny buccal plates of Cassis have been ip 464, \Oporc, mistaken by Gray and Adams for the teeth, which of Cassis. in this genus, andalsoin Triton, are very minute and transparent. Fig. 85. Cassis saburon. (Original). Distribution, 87 species. Tropical seas; in shallow water. West Indies, Mediterranean, Africa, China, Japan, Australia, New Zealand, Pacific, Mexico. GASTEROPODA. 225 Fossil, 36 species. Eocene—. Chili, France. The queen-conch (C. madagascariensis) and other large species are used in the manufacture of shell cameos, p. 38. The periodic mouths (varices) which are very prominent, are not absorbed internally as the animal grows. ONISCIA, Sowerby. Hiymology, oniscus, a wood-louse. Synonym, Morum, Bolten. Type, O. oniscus; O. cancellata. Pl. VI., Fig. 15. Shell with a short spire and a long narrow aperture, slightly truncated in front; outer lip thickened, denticulated ; inner lip granulated. Distribution, 9 species. West Indies, China, Gallapagos, United States. (20 fathoms). Fossil, 3 species. Miocene. United States, Domingo. CASSIDARIA, Lam. Etymology, cassida, a helmet. Synonyms, Morio, Montfort. Sconsia, Gray. Type, C. echinophora. Pl. VI., Fig. 13. Shell ventricose ; canal produced, rather bent. No operculum. Distribution, 6 species. Mediterranean. Fossil, 10 species. Hocene—. Britain, France, &c. BACHYBATHRON, Gaskoin. Shell small, oblong, striated with lines of growth; spire small, depressed, with channelled suture; aperture with callous denticulated lips, like Cyprea, Distribution, 3 species. Fig. 86. Dolum perdiz. (Original). Doxztium, Lam. The Tun. Type, D. galea. Pl. VI., Fig. 12. Shell vyentricose, spirally furrowed; spire small; aperture very large; outer lip crenated. No operculum. Teeth 3, 1, 3. Fig. 86. The genus Macgilliyrayia, formerly assigned to the Atlantidee, belongs here. It comprises the larya forms of several species of Dolium. L3 226 MANUAL OF THE MOLLUSCA. Distribution, 14 species. Mediterranean, Ceylon, €hina, Aus- tralia, Pacific. Fig. 87.* Fossil, 7 species. (? Chalk. Britain). Tertiary. South Europo. Sub-genus, Malea, Valenc. (D. personatum), outer lip thickened and denticulated; inner lip with callous prominences. HARPA, Lam. MHarp-shell. Type, H. ventricosa. Pl. VI., Fig. 11. (= Bue. harpa, L.) Shell ventricose, with numerous ribs, at regular interyals; spire small; aperture large, notched in front. No operculum. The animal has a very large foot, with the front crescent- . shaped, and divided by deep lateral fissures from the posterior part, which is said to separate spontaneously when the animal is irritated. Mostly obtained from deep water and soft bottoms. Distribution, 12 species. Mauritius, Ceylon, Philippines. Pacific. Fossil, 4 species. Eocene—. France. CoLUMBELLA, Lam. Hitymology, diminutive of colwmba, a dove. Type, C. mercatoria. Pl. VI., Fig. 10. Shell small, with a long narrow aperture ; outer lip thickened (especially in the middle), dentated; inner lip crenulated. Operculum very small, lamellar. Distribution, 205 species. Sub-tropical. West Indies, Medi- terranean, India, Gallapagos, California. Small, prettily- * D. perdiz, L. species. 4 natural size (after Quoy). Vanicoro, Pacific. The | roboscis is exserted, and the siphon recurved over the front of the shell. eet et ee ee © Le GASTEROPODA. Tt marked shells; living in shallow water, on sandy flats, or congregating about stones. (Adams.) Fossil, 8 species. Tertiary. (The British species are pisanie.) Sub-genus, Columbellina, D’Orbigny. 4 species. Cretaceous. France, India. OxivA, Lam. Olive, rice-shell. Type, O. porphyria. Pl. VI., Fig. 16. Synonym, Strephona, Brown. Shell cylindrical, polished; spire very short, suture channelled; aperture long, narrow, notched in front; columella callous, striated obliquely; body-whorl furrowed near the base. No operculum in the typical species. Animal with a yery large foot, in which the shell is half immersed; mantle lobes large, meeting over the back of the shell, and giving off filaments which lhe in the suture and furrow. The eyes are placed near the tips of the tentacles. The olives are very active animals, and can turn over, when laid on their back; near low water they may be seen gliding about or burying in the sands as the tide retires; they may be taken with animal baits attached.to lines. They range down- wards to 25 fathoms. Distribution, 120 species. Sub-tropical, West and East America. West Africa, India, China, Pacific. Fossil, 20 species. Eocene—. Britain, France, &c. Sub-genera. Olivella, Sw. O. jaspidea, Pl. VI., Fig. 19. Animal with small, acute frontal lobes. Operculum nucleus sub-apical. Scaphula, Sw. = Olivancillaria, D’Orbigny, Pl. VL., Fig. 18, Frontal lobes large, rounded, operculate. Agaronia, Gray. O. hiatula, Pl. VI., Fig. 17. No eyes or tentacles. Frontal lobes moderate, acute. ANCILLARIA, Lam. Etymology, ancilla, a maiden. Types, A. subulata, Pl. VI., Fig. 20. oolite. ADEORBIS, Searles Wood. Type, A. sub-carinatus. Pl. X., Fig. 17. | Shell minute, not nacreous, depressed, few-whorled, deeply umbilicated ; peristome entire, nearly continuous, situated 1 GASTEROPODA. 267 its inner side, and slightly so externally; operculum shelly, multi-spiral. Distribution, 6 species. West Indies—China. Low water to 60 fathoms. Fossil, 5 species. Tertiary—. Britain. EUOMPHALUS, Sowerby. Etymology, eu, wide, and omphalos, umbilicus. Synonyms, Schizostoma, Bronn. Straparollus, D’Orbigny. Ophileta, Vanuxem. Platyschisma, M‘Coy. Type, HK. pentagonalis. Pl. X., Fig. 18. Shell depressed or discoidal; whorls angular or coronated ; aperture polygonal; umbilicus very large; operculum shelly, round, multi-spiral. (Salter.) Fossil, 80 species, L. silurian—Trias. North America, Europe, Australia. Sub-genus. Phanerotinus, J. Sby. 1840, E. cristatus, Phil. Carb. limestone. Britain. Shell discoidal; whorls separate; outer margin sometimes foliaceous. STOMATELLA, Lam. Etymology, diminutive of stoma, the aperture. Type, S. imbricata. Pl. X., Fig. 19. Shell ear-shaped, regular; spire small; aperture oblong, very large and oblique, nacreous; lp thin, even-edged; operculum circular, horny, multi-spiral. On reefs and under stones at ow water. Distribution, 83 species. Cape, India, North Australia, China, Japan, Philippines. Sub-genus2 Gena, Gray. Spire minute, marginal; no operculum. 16 species. Red Sea, India, Seychelles, Swan River, Philippines. (Adams.) _ Niphonia, Adams. 1 species, Japan. BRODERIPIA, Gray. Etymology, named in honour of W. J. Broderip, Esq., the distinguished conchologist. Type, B. rosea. Pl. X., Fig. 20. Shell minute, limpet-shaped, with a posterior sub-marginal apex ; aperture oval, as large as the shell, brilliantly nacreous. . Distribution, 3 species. Philippines; Grimwood’s Island, South Seas. (Cuming.) N 2 268 MANUAL OF THE MOLLUSCA. FAMILY X,.—HALIOTIDA. Shell spiral, ear-shaped or trochiform; aperture large, nacreous; outer lip notched or perforated. No operculum. Animal with a short muzzle and subulate tentacles; eyes on pedicels at the outer bases of the tentacles; branchial plumes 2; mantle-margin with a posterior (anal) fold or siphon, occupying the slit or perforation in the shell; operculum lobe rudimentary ; lingual dentition similar to trochus. In addition to the true haliotids, we have retained in this group such of the trochiform shells as haye a notched or per- forated aperture. (ES HauioTis, L. Ear-shell. Etymology, halios, marine, and ous (ofos), an ear. Type, H. tuberculata, Pl. X., Fig. 21. Shell ear-shaped, with a small flat spire; aperture very wide, iridescent; exterior striated, dull; outer angle perforated by a series of holes, those of the spire progressively closed. Mus- cular impression horse-shoe shaped, the left branch greatly dilated in front. In ZH. tricostalis (padollus, Montfort) the shell is furrowed parallel with the line of perforations. Animal with fimbriated head-lobes; side-lobes fimbriated and cirrated; foot very large, rounded. Lingual teeth, median small; laterals single, beam-like; uncini about 70, with © denticulated hooks, the first 4 very large. ; The haliotis abounds on the shores of the Channel Talandil P where it is called the ormer, and is cooked after being well ‘ beaten to make it tender. (Hanley.) It is also eaten in Japan. — It is said to adhere very firmly to the rocks with its large foot, — like the limpet. The shell is much used for inlaying and other ornamental purposes. . Distribution, 75 species. Britain, Canaries, Cape, India China, Australia, New Zealand, Pacific, California. Fossil, 4 species. Miocene—. Malta, &c. Sub-genus 2? Deridobranchus, Ehrenberg, D. argus, Red Sea. Shell large and thick, like haliotis, but entirely covered by us ; a thick, hard, plaited mantle of the animal. SroMATIA (Helblin), Lamarck. Etymology, stoma, the aperture. Type, 8. phymotis, Pl. X., Fig. 22. Shell like haliotis, but without perforations, their place being occupied by a simple furrow; surface rugose, spirally ridged; GASTEROPODA. 269 spire small, prominent; aperture large, oblong, outer margin irregular. Distribution, 12 species. Jaya, Philippines, Torres Straits, Pacific. Under stones at low water. (Cuming.) Fossil, M. D’Orbigny refers to this genus 18 species, ranging from the L. Silurian to the chalk. North America, Europe. TEINOTIS, H. and A. Adams, 1854. Shell depressed, elongated, ear-shaped; spire small, and. placed posteriorly; hinder part of the foot in the animal stretches far over the shell. Distribution, 2 species. East India. ScISSURELLA, D’Orbigny. Etymology, diminutive of scissus, slit. Type, 8. crispata, Pl. X., Fig. 23. Synonyms, Anatomus, Montfort ; Woodwardia, Fischer. Shell minute, thin, not pearly; body-whorl large; spire small; surface striated; aperture rounded, with a slit in the margin of the outer lip; operculate. ‘The young have no slit. Animal like Margarita ; tentacles long, pectinated, with the eyes at their base; foot with two pointed lappets and two long slender pectinated cirri on each side; oper- culum ovate, very thin, with an obscure sub-spiral nucleus. No part of the animal was external to the shell. The only living example occurred at Hammerfest, in 40—80 fathoms water; when placed in a glass of sea-water it crawled up the x side and scraped the glass with its Fi# 116. Scssurella. +. tongue. It was pale and translucent when living, but turned inky black after immersion in alcohol. (Barrett, An. Nat. Hist., 2nd ser. vol. 17, p. 206.) Mr. Jeffreys found S. elegans (D’Orbigny) plentifully alive in sea-weed on the coast of Piedmont. It has a multi-spiral operculum, like Margarita. In this species, as noticed by Mr. G. Sowerby, the slit in the peristome of the young shell is converted into a foramen in the adult, as in the Jurassic Trochotoma. Distribution, 5 species. Norway, Britain, Mediterranean. In 270 MANUAL OF THE MOLLUSCA. 7 fathoms water off the Orkneys, and in deep water east of the Zetland Isles. Fossil, 4 species. Tertiary—. Britain Sicily. PLEUROTOMARIA, Defrance Etymology, pleura, side, and tome, notch. Type, P. anghca, Pl. X., Fig. 24. Shell trochiform, solid, fow- whorled, with the surface variously ornamented; aperture sub-quadrate, with a deep slit in its outer margin. The part of the slit which has been progressively filled up forms a band round the whorls. Distribution, 2 species. One occurs in deep water in West Indian seas. Fossil, 400 species. Lower Silurian—Chalk. North America, Europe, Australia. Specimens from clay strata retain their nacreous inner layers; those from the chalk and limestones have lost them, or they are replaced by crystalline spar. Pleurotomarize with wavy bands of colour haye been obtained in the carb. limestone of Lancashire. In this extensive group there are some species which rival the living turbines in magni- tude and solidity, whilst others are as frail as ianthina. Sub-genera. Scalites, Conrad, IL. Silurian, New York. Shell thin ; whorls angular, flat above (tabulated), 8 species. — L. Silurian—Carb. 4 Polytremaria, D’Orbigny, is founded on P. catenata — (Koninck),in which the margins of the slit are wavy, converting © it into a series of perforations. : Catantostoma (clathratum) Sandberger, 1842. Shell like Pleurotomaria; last whorl deflected, peristome incomplete, slightly varicose, irregular. fossil, Devonian, Eifel. Raphistoma (angulata), Hall. lL. Silurian, United States, Canada. Shell depressed, outer lip sinuated. In BR. compacta (Salter) the spire is sunk and basin-shaped, the umbilical side flat, and the last whorl a little disunited. : 7 se OR re el Mourcuison1A, D’Archiac. Etymology, named in honour of Sir Roderick I, Murchison. Type, M. bilineata, Pl. X., Fig. 25. Shell elongated, many-whorled ; whorls variously sculptured, and zoned like plewrotomaria ; aperture slightly channeled in front; outer lip deeply notched. The murchisonie are characteristic fossils of the paleeozoic “a> GASTEROPODA. paid: rocks; they have been compared to elongated plewrotomarie, or to cerithia with notched apertures; the first suggestion is most probably correct. Fossil, 50 species. LL. Silurian—Permian. North America, Europe. TrocHoTomA, Lycett. Fitymology, Trochus, and tome, a notch. Synonym, Ditremaria, D’Orbigny. Type, T. conuloides, Pl. X., Fig. 26. Shell trochiform, slightly concave beneath; whorls flat, spirally striated, rounded at the outer angles; lip with a single perforation near the margin. Fossil, 10 species. Lias—Coral Rag. Britain, France, &c. ? CIRRUS, Sowerby. Etymology, cirrus, a curl. Type, OC. nodosus, Sby. Min. Con. t. 141 and 219. Shell sinistral, trochiform, base leyel; last whorl enlarging rather more rapidly, somewhat irregular. Fossil, 2 species. Inf. oolite, Bath oolite. Britain, France. This genus was founded on a plewrotomaria, a ewomphalus, and C. nodosus. (vy. Min. Con.) It is still doubtful what species may be referred to it. Fig. 117.* TANTHINA, Lam. Violet-snail. Etymology, ianthina, violet-coloured. Type, helix ianthina, L. (I. fragilis, Lam.) Pl. X., Fig. 27. Shell thin, translucent, trochiform; nucleus minute, styliform; sinistral; whorls few, rather yentricose ; aperture four-sided ; columella tortuous ; lip thin, notched at the outer angle. Base of the shell deep violet, spire nearly white. Animal head large, muzzle-shaped, with a tentacle and eye- * Fig. 117. Janthina fragilis, Lam. (from Quoy and Gaimard), Atlantic. a, raft, 6, egg capsules; c, gills; d, tentacles and eye-stalks. 272 MANUAL OF THE MOLLUSCA. pedicel on each side, but no eyes; foot small, secreting a float composed of numerous cartilaginous air-vesicles, to the under surface of which the ovarian capsules are attached. Lingual ribbon, rachis unarmed ; uncini numerous, simple (like scalaria). Branchial plumes 2. Sexes separate. Distribution, 10 species. Atlantic, Coral sea. The ianthinsz, or oceanic-snails, are gregarious in the open sea, where they are found in myriads, and are said to feed on the small blue acelephee (velella). They are frequently drifted to the southern and western British shores, especially when the wind continues long from the south-west ; in Swansea Bay the animals haye been found quite fresh. When handled they exude a violet fluid from beneath the margin of themantle. In rough weather they are driven about and their floats broken, or detached, in which state they are often met with. The capsules beneath the farther end of the raft haye been observed to be empty, at a time when those in the middle contained young with fully formed shells, and those near the animal were filled with eges. They have no power of sinking and rising in the water. The raft, which is much too large to be withdrawn into the shell, is generally thought to be an extreme modification of the oper- culum ; but M. Lucaze-Duthiers, who has seen the raft formed, denies this. Itis built up from glutinous matter secreted by the foot.* ? Holopea. (symmetrica), Hall. 1847. Outer lip sinuated near the base. JZ. Silurian, New York. FAMILY XI.—FISSURELLIDZ. Shell conical, limpet-shaped; apex recurved ; nucleus spiral, often disappearing in the course of growth; anterior margin notched or apex perforated; muscular impression horse-shoe shaped, open in front. Animal with a well-developed head, a short muzzle, subulate tentacles, and eyes on rudimentary pedicels at their outer bases; sides ornamented with short cirri; branchial plumes 2, sym- metrical; anal siphon occupying the anterior notch or perforated summit of the shell. Lingual dentition similar to trochus.f FISSURELLA, Lam. Key-hole limpet. Etymology, diminutive of fissura, a slit. Type, F. Listeri, Pl. XI., Fig. 1. * Annales des Sciences Naturelles, 1865. + Fissurella is the best gasteropod for comparison with the bivalves; its large gills, placed one on each side, and its symmetrical shell, pierced with a median orifice for the escape of the out-going branchial current, are unmistakable indications of homologies — with the lamelli-branchiata. See p. 39. gp raga <- : ’ E mv GASTEROPODA. 273 Shell oval, conical, depressed, with the apex in front of the centre, and perforated ; surface radiated or cancellated; muscular impression with the points incurved. In yery’young shells the apex is entire and sub-spiral; but as the perforation increases in size, it encroaches on the summit and gradually removes it. The key-hole limpets are locomotive ; Fig. 118. Fisstrelia. (Wilton.) they chiefly inhabit the laminarian zone, but range downwards to 50 fathoms. For dentition see Fig. 118. Distribution, 182 species. America, Britain, South Africa, India, China, Australia, Upper California, Cape Horn. Fossil, 30 species. Carb.; oolites—. Britain and France. Sub-genera. Pupillia, Gray. F. apertura, Born. (=hiantula, Lam.) Shell smooth, surrounded by a sharp white edge; per- foration very large. Distribution, South Africa. Fissurellidea, D’Orbigny. F. hiantula, Lam. (=megatrema, D’Orbigny.). Shell cancellated; covered by the mantle of the animal. 3 species. Cape and Tasmania. (Macroschisma, Sw.) FF. macroschisma, Pl. XI., Fig. 2. Anal aperture close to the posterior margin of the shell. The animal is so much larger than its shell as to be compared to the testacelle by Mr. Cuming. Distribution, Philippines and Swan River. Lucapina, Gray. F. elegans, Gray (=aperta, Sby.). Shell white, cancellated, margin crenulated ; covered by the reflected mantle. 38 species. California. PUNCTURELLA, Lowe. Synonyms, Cemoria, Leach. Diadora, Gray. Type, P. noachina, Pl. XI., Fig. 3. Shell conical, elevated, with the apex recuryed ; perforation in front of the apex, with a raised border internally; surface cancellated. Distribution, 6 (?) species. Greenland, Boreal America, N 3 274 MANUAL OF THE MOLLUSCA. Norway, North Britain, Tierra-del-Fuego. In 20—100 fathoms water. Fossil, in the glacial formations of North Britain. RIMULA, Defrance. Etymology, diminutive of rima, a fissure. Synonym, Rimularia. Recent type, R. Blainyilliui, Pl. X1., Fig. 4. Shell thin and cancellated, with a perforation near the anterior margin. Distribution, several species found on sandy mud at low water, or dredged in from 10—25 fathoms. Philippines (Cuming). Fossil, 3 species. Bath oolite—coral rag. Britain and France. EMARGINULA, Lam. Etymology, diminutive of emarginata, notched. Type, Ki. reticula, Pl. XI., Figs. 5 and 6. Shell oval, conical, elevated, with the apex recurved; surface cancellated; anterior margin notched. Muscular impression with recurved points. The nucleus (or shell of the fry) is spiral, and resembles scisswrella. The anterior slit is very variable in extent. The animal of emarginula (and also of puncturella) has an isolated cirrus on the back of the foot, perhaps representing the operculigerous lobe. (Forbes.) Lingual dentition, median teeth sub-quadrate ; laterals 4, oblong, imbricated ; uncini about 60, the first large and thick, with a lobed hook, the rest linear, with serrulated hooks. (Lovén.) Distribution, 40 species. West Indies, Britain, Norway, Philippines, Australia. Range from low water to 90 fathoms. Fossil, 40 species. Trias—. Britain and France. Sub-genus. Hemitoma, Sw. Type, K. octoradiata (EK. rugosa, Pl. XI., Figs. 7 and 8). Shell depressed, anterior margin slightly channeled. PARMOPHORUS, Blainyille. Duck’s-bill impet. Etymology, parme, a shield, and phoreus, a bearer. Type, P. australis, Pl. X1., Fig. 9. Synonym, Scutus, Monttf. Shell lengthened-oblong, depressed; apex posterior; front margin arched. Muscular impression horse-shoe shaped, elon- gated. The shell is smooth and white, and permanently covered by the reflected borders of the mantle. The animal is black, and very large compared with the shell; its sides are fringed with short cirri, and its eyes sessile on the outer bases of thick GASTEROPODA. 275 tentacles; it is found in shallow water, and walks freely. (Cuming.) Distribution, 15 species. New Zealand, Australia, Philippines, Singapore, Red Sea, Cape. Fossil, 3 species. Eocene?—. Paris Basin. Famity XIJ.—CaLyptrRHIDz. Bonnet-limpet. Shell limpet-like, with the apex more or less spiral; interior simple, or divided by a shelly process, variously shaped, to which the adductor muscles are attached. Animal with a distinct head; muzzle lengthened ; eyes on the external bases of the tentacles ; branchial plume single. Lin- gual teeth single, uncini 3, as in Fig. 119, which shows dentition POND bes Fig. 119. Crepidula. (Wilton.) of crepidula. The rostrum is prominent and split, but non- retractile ; the median tooth hooked and dentate; the first, or first and second laterals serrated, the third claw-shaped and simple. Loyén places this family next to the Velutinide. The bonnet-limpets are found adhering to stones and shells; most of them appear never to quit the spot on which they first settle, as the margins of their shells become adapted to the surface beneath, whilst some wear away the space beneath their foot, and others secrete a shelly base. Both their form and colour depend on the situation in which they grow; those found in the cayities of dead shells are nearly flat, or even concave above, and colourless. They are presumed to feed on the sea- weed growing round, them, or on animalcules; a calyptrea, which Professor Forbes kept in a glass, ate a small sea slug (goniodoris) which was confined with it. Both calyptrea and pileopsis sometimes coyer and hatch their spawn in front of their foot. (Alder and Clarke.) Dr. Gray arranges the bonnet-limpets next after the yerme- tide ; their lingual dentition is like velutina. 276 MANUAL OF THE MOLLUSCA. CALYPTREA, Lam. Cup-and-saucer limpet. Etymology, calyptra, a (lady’s) cap. Synonym, Lithedaphus, Owen. Types, C. equestris, Pl. XI., Fig. 10. C. Dillwynnii, Fig. 11. Shell conical; limpet-shaped; apex posterior, with a minute, spiral nucleus; margin irregular; interior with a half-cup shaped process on the posterior side, attached to the apex, and open in front. Surface rugose or cancellated. Animal with a broad muzzle; tentacles rather short; lanceo- late; eyes on bulgings at the outer bases of the tentacles ; mantle-margin simple, sides plain. Found under stones, be- tween tide-marks, and in shallow water. (Cuming.) Distribution, 50 species. West Indies, Honduras, Britain, Mediterranean, Africa, India, Philippines, China, Japan, New Zealand, Gallapagos, Chih. Fossil, 31 species. Carb. ? chalk—. Britain, France, &c. Sub-genera. Crucibulum, Schum. (Dispotza. Say., Calypeopsis, © Less.) Example, O. rudis, Pl. XI., Fig. 12. Shell spinulose; internal cup entire; attached by one of its. sides. Distribution, West America, Japan, West Indies. Found on shells, with its base worn, or smoothed by a shelly deposit. (Gray.) Between this section and the next there are several intermediate forms. Trochita, Schum. (Infundibulum, J. Sby., Galerus, Humph. Trochatella and Siphopatella, Lesson.) ‘TT. radians, Pl. XL, Figs. 13, 14. (=Patella trochoides, Dillw.). ‘TT. sinensis, Pl Ry Bag. 15. Shell circular, more or less distinctly spiral; apex central; jnterior with a more or less complete sub-spiral partition. Distribution, chiefly tropical, but ranges from Britain to New Zealand. T’. prisca (McCoy) is found in the carb. limestone in Ireland ; and several large species occur in the London clay and Paris basin. The recent ©. sinensis—the ‘‘Chinaman’s hat” of collectors—is found on the southern shores of England, and in the Mediterranean, in 5—10 fathoms water. (Forbes.) Its : lingual dentition is given by Loyén; median teeth broad, hooked, denticulatcd ; uncini 3, the first hooked and serrated, 2, 3, claw-shaped, simple. - CREPIDULA, Lam. Htymology, crepidula, a smaii sandal, * 95. eee GASTEROPODA. 277 Type, C. fornicata, Pl. XTI., Fig. 16. Synonym, Crypta, Humph. Shell oval, limpet-like; with a posterior, oblique, marginal apex; interior polished, with a shelly partition covering its posterior half. The crepidule resemble the fresh-water navicelle in form ; but the internal ledge which mimics the columella of the nerite, is here the basis of the adductor muscles. They are sedentary on stones and shells, in shallow water, and are sometimes found adhering to one another in groups of many successive generations. The specimens or species which lve inside empty spiral shells are very thin, nearly flat, and colourless. Distribution, 54 species. West Indies, Honduras, Mediter- ranean, West Africa, Cape, India, Australia, West America. Fossil, 14 species. Hocene—. France, North America, and Patagonia. PILEopsis, Lam. Bonnet-limpet. Etymology, pileos, a cap, and opsis, like. Synonyms, Capulus, Montf. Brocchia, Bronn. Type, P. hungaricus, Pl. XI., Fig. 17, P. militaris, Pl. XI., Fig. 18. Shell conical; apex posterior, spirally recurved; aperture rounded ; muscularimpression horse-shoe shaped. - Animal with a fringed mantle-margin; lingual teeth like calyptreea. P. hungaricus (the Hungarian-bonnet) is found on oysters in 5 to 15 fathoms water; more rarely as deep as 80 fathoms, and then yery small. P. militaris is extremely like a velutina. Distribution, 8 species. West Indies, Norway, Britain, Mediterranean, India, Australia, California. Fossil, 20 species. Lias—. Europe. Sub-genus. Amathina, Gray. A. tricarinata, Pl. XI., Fig. 19. Shell depressed, oblong; apex posterior, not spiral, with three strong ribs diverging from it to the anterior margin. Platyceras, Conrad (acroculia, Phil.). P. vetustus. Carb., limestone. Britain. Fossil, 20 species. Deyonian—Trias. America, Europe. Metoptoma, Phillips. M. Pileus, Ph. Shell limpet-like, side beneath the apex truncated, resembling the posterior yalye of a chiton. 7 species. Carb. limestone. Britain. 278 MANUAL OF THE MOLLUSCA. Hipponyx, Defrance. Etymology, hippos, a horse, and onyx, a hoof. Type, H. cornucopia, Pl. XI., Figs. 20, 21. Shell thick, obliquely conical, apex posterior; base shelly, with a horse-shoe shaped impression, corresponding to that of the adductor muscle. Distribution, 13 species. West Indies, Persian Gulf, Philiy - pines, Australia, Pacific, West America. Fossil, 10 sp. U. chalk—. Britain, France, North America. Sub-genus. Amalthea, Schum. A. conica. Like hipponyx, but forming no shelly base; surface of attachment worn and marked with a cresent-shaped impression. Often occurs on living shells, such as the large turbines and turbinelle of the Eastern seas. FamIty XIII.—PATELLIDA. Limpets. Shell conical, with the apex turned forwards; muscular im- pression horse-shoe shaped, open in front. Animal with a distinct head, furnished with tentacles, bear- ing eyes at their outer bases; foot as large as the margin of the shell; mantle plain or fringed. Respiratory organ in the form of one or two branchial plumes, lodged in a cervical cavity; or of a series of lamellze surrounding the animal between its foot and mantle. Mouth armed with horny upper jaw, and a long ribbon-like tongue, furnished with numerous teeth, each con- sisting of a pellucid base and an opaque hooked apex. The order cyclo-branchiata of Cuyier included the chitons and the limpets, and was characterised by the circular arrangement of the branchize. At a comparatively recent period it was ascer- tained that some of the patellze (acmea) had a free, cervical gill; whilst the chitons exhibited too many peculiarities to admit of being associated so closely with them. Professor Forbes has very happily suggested that the cyclo-branchiate gill of patella is, in reality, a single, long branchial plume, originating on the left side of the neck, coiled backwards round the foot, and attached throughout its length. This view is con- firmed by the circumstance that the gill of the sea-weed limpets (nacelle) does not form a complete circle, but ends without passing in front of the animal’s head. PATELLA, L. Rock limpet. Etymology, patella, a dish. Synonyms, Helcion Montfort ; Cymba, Adams. GASTEROPODA. 279 Example, P. longicostata. Pl. XI., Fig. 22. Shell oval, with a sub-central apex; surface smooth, or ornamented with radiating striz or ribs; margin even or spiny ; interior smooth. Animal with a continuous series of bran- chial lamelle ; mantle-margin fringed ; eyes sessile, externally, on the swollen bases of the tentacles; mouth notched below. Lingual teeth 6, of which 4 are central, and 2 lateral; =% uncini 3. Fig. 120 shows the teeth, but not / the uncini of P. vulgata. The Cape limpets (e.g. P. denticulata) have a minute central | tooth, which is wanting in any other species Fig. 120, Patella hitherto examined. (Wilton.) vulgata. The dental canal of the common British (Osim! Wilton.) limpet (P. vulgata) is rather longer than its shell; it has 160 rows of teeth, with 12 teeth in each row, or 1,920 in all. (Forbes.) The limpets live on rocky coasts, between tide- marks, and are consequently left dry twice every day; they adhere very firmly by atmospheric pressure (15 lbs. per square inch), and the difficulty of detaching them is increased by the form of the shell. On soft calcareous rocks, like the chalk of the coast of Thanet, they live in pits half an inch deep, pro- bably formed by the carbonic acid disengaged in respiration ; on hard limestones only the aged specimens are found to have worn the rock beneath, and the margin of their shell is often accom- modated to the inequalities of the surrounding surface. These circumstances would seem to imply that the limpets are sedentary, and live on the sea-weed within reach of their tongues, or else that they return to the same spot to roost. On the coast of Northumberland we haye seen them sheltering themselves in the crevices of rocks, whose broad surfaces, over- grown with nullipores, were covered with irregular tracks, apparently rasped by the limpets in their between tides excursions.* The limpet is mucn used by fishermen for bait; on the coast of Berwickshire nearly 12,000,000 have been collected yearly, until their numbers are so decreased that collecting them has become tedious. (Dr. Johnston.) In the north of Ireland they are used for human food, especially in seasons of scarcity ; * If limpets are placed in stale water, or little pools exposed to the hot sun, they creep Out more quickly than one would expect; the tracks they leave are very peculiar, and not likely to be mistaken when once seen, 280 MANUAL OF THE MOLLUSCA. many tons weight are collected annually near the town of Larne alone. (R. Patterson.) On the western coast of South America there is a limpet which attains the diameter of a foot, and is used by the natives asa basin. (Cuming.) The common limpet makes oval pits in timber as well as in chalk. Small individuals sometimes roost habitually on larger specimens, and make an oval furrow on the shell. The surface on which lmpets roost, and some space around it, is often covered with radiating striz not parallel like those produced by their teeth on nullipore. Mr. Gaskoin has a lmpet-shell encrusted with nullipore, which other limpets have rasped all over. In M. D’Orbigny’s collection of Cuban shells there is a group of oysters (0. cornucopic), with a colony of the Hipponyx mitrula sheltered in their interstices; these limpets haye not only fed on the nullipore with which the oysters are encrusted, but have extensively eroded the epidermal layer of shell beneath.* As to the Calyptreide generally, although furnished wita lingual teeth (Fig. 96) like those of the animal-feeding Velutina, and themselves manifesting carnivorous propensities (p. 275), it is difficult to understand how they can travel in quest of food. The shape of some species of limpet is believed to vary with the nature of the surface on which they habitually ive. Thus the British Nacella pellucida is found on the fronds of the tangle, and assumes the form called N. /evis, when in lives on their stalks. (Forbes.) The 310 MANUAL OF THE MOLLUSCA HELIcInA, Lamarck. Type, WH. Neritella, Lam. Synonyms, Oligyra, Say. Pachytoma, Sw. Ampultina, BL - Pitonillus, Montfort. Shell globose, depressed or keeled, callous beneath; aperture squarish or semi-lunar; columella flattened; peristome simple, expanded ; operculum shelly or membranous, squarish or semi- ovate, lamellar. Animal like Cyclophorus ; lingual teeth 3.1.3. (Gray.) Distribution, 162 species. West Indies, Tropical America, Pacific Islands, Australian Islands, Philippines. Sub-genera. Lucidella (aureola), Gray. Peristome more or less toothed internally. 8 species. West Indies, Tropical — America. Trochatella (pulchella), Sw. Shell not callous beneath; peri- stome simple, expanded. West Indies 20 species, Venezuela 1. Alcadia, Gray. A. Brownei, Pl. XII., Fig. 48. Jamaica. Shell helix-shaped, often velvety, callous beneath; columella flattened, straight; peristome slit in front; operculum shelly, semi-oyate, with a tooth-like process adapted to the slit in the peristome. Distribution, 17 species. Cuba, Jamaica, and Hayti. STroasTomA, C. B. Adams. Etymology, stoa, pillared, stoma, mouth. Type, 8. pisum, Ad. Shell minute, globose-conic or depressed, spivally striated ; aperture semi-oval; peristome continuous; inner margin ~ straight, forming a small spiral keel round the umbilicus ; operculum shelly, lamellar. Distribution, 19 species. Jamaica. S. succinewm (Electrina, © Gray) has smooth whorls. I. Opara, Polynesia. 60 new species — have been added by the Hon. H. Chitty, who divides them ~ among seyeral new genera. 5 Famity VII.—AcicuLIpz. Shell elongated, cylindrical ; operculum thin, sub-spiral. Aximal with the muzzle rather produced, slender and trun-~ cated ; eyes sessile on the upper part of the head, behind the base of the slender tentacles ; foot oblong, short, pointed behind. AcIcuLA, Hartmann, Type, A. fusca, Pl. XII, Fig. 44. GASTEROPODA. 311 Synonym, Acme and Acmaea, Hartmann.* Shell minute, slender, nearly imperforate; peristome slightly thickened, margins sub-parallel, joined by a thin callus; oper- culum hyaline. Distribution, 7 species. Britain, Germany, France; Vanicoro (on leaves). A. fusca is found in low, marshy situations, at the roots of grass; it occurs fossil in the Newer Pliocene of Essex. (J. Brown.) GEOMELANIA, Pfeiffer. Type, G. Jamaicensis, Pfeiffer. Etymology, Ge, the ground (i.e. terrestrial). Shell imperforate, turreted; aperture entire, effused; peri- stome simple, expanded; margins joined, basal produced into a tongue-shaped process; operculum oval, pellucid, whorls few, rapidly enlarging. Distribution, 21 species. Jamaica. ORDER IIJ.—OPISTHO-BRANCHIATA. Shell rudimentary or wanting. Branchie arborescent or fasciculated, not contained in a special cavity, but more or less completely exposed on the back and sides, towards the rear (Opisthen) of the body. Sexes united. (M. Edwards.) The molluscs of this order may be termed sea-slugs, since the shell, when it exists, is usually small and thin, and wholly or partially concealed by the animal. When alarmed or removed from their native element, they retract their gills and tentacles, and present such a questionable shape that the inex- perienced naturalist will be likely enough to return them, with the refuse of the dredge, into the sea. Their internal structure presents many points of interest; in some the gizzard is armed with horny spines, or large shelly plates; in others the stomach is extremely complicated, its ramifications and those of the liver being prolonged into the papille, which are said to be branches of the respiratory organ. The tongue is always armed, but the number and arrangement of the lingual teeth is ex- ceedingly variable, even in the same family; usually the dental membrame is broad and short, with many similar teeth in each row. The lingual dentition is extremely varied in the Bullide. In * All given in the same year, 1821, the name Acmaea having been employed by Eschscholtz for a genus of limpets; Acicula has been retained by Pfeiffer and Gray for this land-shell. 312 MANUAL OF THE MOLLUSCA, - Philine aperta there is no central tooth; and the laterals, which increase rapidly in size backwards, haye a finely denticulated membranous inner edge. In Tornatella and Bulla (physis) the rachis is unarmed, and the lateral teeth are nume- Fr rous and similar; in Acera, com, Cylichna, and Amphisphyra h ; ee there is a minute central \ tooth. a The alimentary canal ter- minates more in the rear of Fig. 186. Philine aperta. (Wilton.) the body than in the other univalye shell-fish.* The gills are behind the heart, and the auricle behind the ventricle ; conditions which characterise the embryonic state of the mollusca generally. Comparatively little is known of the geographical distribution of these animals; they have been found wherever the requisite search has been made, and are probably much more numerous than at present estimated. Considerable additions, however, _have been made to our knowledge on this subject by the researches of Kelaart in Ceylon and A. Adams in the Chinese seas. The shell-bearing genera flourished in the period when the secondary strata were deposited. The living species are chiefly animal-feeders, preying on other shell-fish and on zoophytes. Section A.—TEcCTI-BRANCHIATA.} Animal usually provided with a shell, both in the larval and adult state; branchize covered by the shell or mantle; sexes united. FAmMILy I.—TIoORNATELLIDZA, Shell external, solid, spiral or conyoluted ; sub-cylindrical ; * In the cuttle-fishes and pteropods it is bent upon itself ventrally, in the sea-snails dorsally, terminating in front, near itg origin; the vascular system partakes of this flexure, and the gills are in advance of the heart. (Huxley.) ¢ Mono-pleuro-branchiata. Bl. Pomato-branchia, (from poma, a lid). Wiegm. The order Zecti-branchiata of Cuvier included only the family Bullide ; it is here made to comprise the Jnfero-branchs also; no object being gained by the multiplics- tion of descriptive epithets. ea - GASTEROPODA, 313 aperture long and uarrow; columella plaited; sometimes operculated. Animal with a flattened, disk-like head, and broad obtuse tentacles ; foot ample, furnished with lateral and operculigerous lobes. The shells of this family are chiefly extinct, ranging from the period of the coal strata, and attaining their greatest develop- ment in the cretaceous age. Tornatella is essentially related to Bulla, but presents some resemblance to the Pyramidellide in its plaited and operculated aperture ; in Yornatina the nucleus, or apex, is sinistral. The spiral striae which ornament many of the species are punctate, as in the Bullide; and the outer lip often remarkably thickened, as in Auricula. TORNATELLA, Lamarck. Type, T. tornatilis, Pl. XTV., Fig. 1. Synonyms, Actzeon, Montf. (not Oken), Dactylus (solidulus), Schum. ? Monoptygma (elegans), Lea. Shell solid, oyate, with a conical, many-whorled spire; Fig. 137. spirally grooved or punctate-striate ; aperture long, narrow, rounded in front; outer lip sharp; columella with a strong, tortuous fold; operculum horny, elliptical, lamellar. Animal white; head truncated and slightly notched in front, furnished posteriorly with recumbent tentacular lobes, and small eyes near their inner bases; foot oblong, lateral lobes slightly reflected on the shell. Lingual teeth 12.12, similar, with long simple hooks. Distribution, 16 species. United States, Britain, Senegal, Red Sea, Philippines, Japan, Peru. 1. tornatilis inhabits deep water—60 fathoms. (Forbes.) Fossil, 70 species. Trias—Lias—. North America, Europe, South India. Sub-genera. Cylindrites (Llhwyd), Lycett. OC. acutus, Sby. Pl. XIV., Fig. 2. (A.) Shell smooth, slender, sub-cylindrical, spire small, aperture long and narrow, columella rounded, £ 814 MANUAL OF THE MOLLUSCA. twisted, and directed slightly outwards. (B.) Shell oval, spire sunk, whorls with acute margins. Bath Oolite, Britain. Acteonina, D’Orbigny. ‘Tornatelle ‘‘ without columella plaits,” 30 species. Carb.—Portlandian (including Cylindrites). Acteonella, D’Orbigny. A. Renauxiana, Pl. XIV., Fig. 3. Shell thick, cone-like or convoluted, spire short or concealed, aperture long and narrow, columella with 3 strong and regular spiral plaits in front. Distribution, 18 species. Chalk; Britain, France. Acteon Cabanetiana, D’Orbigny. (ltieria, Matheron, 1842), Coral-rag, France, belongs to the genus Nerinea (D’Orbigny), p. 244. CINULIA, Gray. Type, C. avellana, Pl. XIV., Fig. 4. Synonyms, Avellana and Ringinella, D’Orbigny. Shell globular, thick, spirally grooved and punctate, spire small; aperture narrow, rounded and sinuated in front; outer lip thickened and reflected; crenulated inside, columella with several tooth-lke folds. Fossil, 21 species. Neocomian—Chalk. Britain, France. RINGICULA, Y. p. 222, Pl. V., Fig. 21. GuopiconcHa, D’Orbigny. Type, G. rotundata, D’Orbigny. Fossil, 6 species. Chalk. France. Shell ventricose, smooth, aperture crescent-shaped, simple, not toothed or thickened on the columellar side. VARIGERA, D’Orbigny. 1850.* Type, VY. Guerangi, D’Orbigny. Fossil, 8 species. Neoc:—. Chalk. France. Shell like Globiconcha, but with lateral varices. TYLOSTOMA, Sharp. 1849. Type, T. Torrubie, Sharp. Etymology, Tulos, a callosity, stoma, mouth. Shell ventricose, smooth or punctate-striate, spire moderate, aperture ovate-lunate, pointed above, rounded in front; outer lip periodically (once or twice in a whorl) thickened inside and expanded, rising slightly; inner lip callous, spread over body- whorl. Distribution, 4 species. lL. Cretaceous rocks, Portugal. _ ™ The dates of M. D’Orbigny’s genera, given in the Prodrome de Paleontologe, are dates of znvention ; the names were not published, in many instances, until years efterwarda, ee ae ee GASTEROPODA. 315 ? PreRoDoNTA, D’Orbigny. Type, P. inflata, D’Orbigny. Fossil, 8 species. Chalk. France. Shell oblong, ventricose, spire elongated ; aperture oval, lip slightly expanded, notched in front, and with a tooth-like ridge internally, remote from the margin. ? TORNATINA, A. Adams. Type, T. voluta. Pl. XIV., Fig. 5. Shell cylindrical or fusiform, spire conspicuous, apex sinistral, suture channeled, columella callous, 1-plaited. Animal with a broad, trigonal head, rounded in front; ten- tacular lobes triangular, with eyes at their outer bases; foot short, truncated in front. Distribution, 24 species. "West Indies, United States, Medi- terranean, Philippines, China, Australia. On sandy bottoms, ranging to 35 fathoms. (Adams.) Fossil, 13 species. Tertiary. Volvula, Adams (Bulla acuminata, Brug.), is a small con- voluted shell, with the spire concealed, and the columella obsoletely folded; it is referred to Cylichna by Lovén, to Ovulum by Forbes. Distribution, 12 species. Britain, Medi- terranean, Asia. J ossil, Pliocene—. Suffolk. Famity II.—BvuLLIpDz. Shell globular or cylindrical, convoluted, thin, often punctate- striated ; spire small or concealed; aperture long, rounded and sinuated in front; lip sharp. No operculum. Animal more or less investing the shell; head a flattened disk,* with tentacular lobes, often united ; eyes immersed in the centre of the disk, or wanting; foot oblong, furnished with a posterior lobe (meta-podiwm), and side-lobes (epipodia); gill single on the right side of the back, covered by the shell; mantle-margin simple or expanded, and enveloping the shell. Lingual dentition very various; central teeth often wanting, laterals single or numerous. Gizzard armed with calcareous plates. Sexes united. * The cephalic expansion of the Bullide is formed by the fusion of the dorsal and oral tentacles. (Cuvier.) The tentacular lobes, or posterior part of the disk, is sup- plied with nerves from the olfactory ganglia; the anterior portion of the disk receives bravches from the labial nerve, which comes from the front margin of the cerebroid. ( Hancock.) P2 316 MANUAL OF THE MOLLUSCA. The Bullide are animal feeders; they are said to use their lateral lobes for swimming. About 150 recent species have been described by Mr. A. Adams in Sowerby’s Thesaurus Con= chyliorum. Fossil species date from the lower Oolites; one ig found in the Aralo-Caspian formation. Buiua, Lamarck. Bubble-shell. Type, B. ampulla, Pl. XIV., Fig. 6. Synonym, Haminea (hydatis), Leach. Shell oval, ventricose, convoluted, external or only partially invested by the animal; apex perforated; aperture longer than the shell, rounded at each end; lip sharp. Animal with a large cephalic disk, truncated in front, bilobed behind, the lobes laminated beneath; eyes sub-central, immersed or wanting; lateral lobes very large, reflected on the sides of the shell, posterior lobe covering the spire; foot quadrate ; gizzard furnished with 3 chiton-like plates; teeth. ? Bulla naucum (Atys, Montf. Alicula, Ehr. Rowania, Leach). Pl. XIV., Fig. 7; has the columella twisted, and the spire entirely concealed. Distribution, 50 species. In all temperate and tropical seas, especially on sandy bottoms, ranging from low water to 25 or 30 fathoms. Fossil, 70 species. Oolite—. South America, United States, Europe. Sub-genera ? Crypt-opthalmus (smaragdinus), Ehr. Red Sea. Shell scarcely convolute, fragile, oval, convex, without spire or columella. Animal semi-cylindrical, head with short tentacular lobes, eyes small, concealed under the lateral margins of the head, mantle and lateral lobes enveloping the shell. Phaneropthalmus, A. Adams. (Xanthonella, Gray) B. lutea, Quoy, New Guinea. Shell oval, convex, pointed behind, columella margin with a curved process. Animal long, cylin- drical, head with short tentacular lobes, eyes in middle of disk, lateral lobes enveloping. Linteria, A. Adams (Glauconella, Gray ; Smaragdinella, A. Adams), Bulla viridis, Rang. Pl. XIV., Fig. 8. Shell oval, widely open, showing the rudimentary internal spire. Animal with a squarish, disk-like head, eyes sessile in the centre; mantle not inyesting; a posterior lobe; lateral lobes enyelop- ing. AcERA, Miller. Type, A. bullata, Pl. XIV., Fig. 9. Etymology, Akeros, hornless. GASTEROPODA. 317 Shell thin, flexible, globosely-cylindrical, spire truncated, whorls channeled ; aperture long, expanded and deeply sinuated in front, outer margin disunited at the suture; columella open, exposing the whorls. Animal with a short and simple head-lobe, truncated in front and eyeless; lateral lobes nearly concealing the shell; lingual teeth hooked and serrulate, laterals about 40, narrow, claw- shaped ; gizzard armed with horny teeth. Distribution, 7 species. Greenland, Britain, Mediterranean, Zanzibar, India, New Zealand. A. bullata is found amongst weed, in 1—15 fathoms water. (Forbes. ) Cyxicuna, Lovén. Type, C. cylindracea, Pl. XTV., Fig. 10. Synonym, Bullina, Risso. Shell strong, cylindrical, smooth or punctate-striate; spire minute or truncated; aperture narrow, rounded in front; columella callous, with one plait. Animal shert and broad, not investing the shell; head flattened, truncated in front, with sub-centrally immersed eyes, tentacular lobes more or less united; foot oblong, posterior and lateral lobes not much developed; gizzard armed; lingual teeth squarish, recuryed and serrated, with 1 large and 5 or 6 small hooked laterals. Distribution, 40 species. United States, Greenland, Britain, Red Sea, Australia. Fossil, Tertiary—. Britain. ? KLEINELLA, A. Adams. Shell thin, dotted, striated, columella smooth, spire obtuse. Distribution, 1 species. Japan. AMPHISPHYRA, Loyén. Type, A. pellucida, Johnst. (Amphi-sphyra, double hammer) Synonyms, Utriculus (part), Brown. Rhizorus, Montfort. Diaphana, Brown. Shell small, thin, ovate, truncated, spire minute papillary, aperture long. Animal entirely retractile into its shell; head wide, short, with lateral triangular tentacles; the eyes behind them minute, immersed; muzzle bilobed in front; foot oblong, truncated in front, notched behind ; teeth 1.1.1, central quadrate, serrulate ; laterals broad, hooked. 818 MANUAL OF THE MOLLUSCA. Distribution, 7 species. United States, Norway, Britain, Borneo, Mexico. BuccINuLvs, Blanchard. Shell thick ; columella with two plaits; aperture small, entire in front. Distribution, 10 species. South Seas. APLUSTRUM, Schumacher. Type, Bulla aplustre, Pl. XTV., Fig. 11. Etymology, aplustre, a ship’s flag. Synonyms, Bullina, Fér. Hydatina (physis), Schum. Bullinula (scabra), Beck. Shell oval, ventricose, highly coloured ; spire wide, depressed ; aperture truncated in front; outer lip sharp. Animal with a very large foot, extending beyond the shell all round, and capable of enveloping it; a posterior lobe reflected on the spire; mantle not investing ; tentacular lobes large, oval, ear-shaped; labial tentacles four; eyes small, black, sessile at the inner bases of the tentacles; lingual teeth (B. physis) 13.0.138, serrated. Distribution, 10 species. United States, West Indies, Mauri- tius, Ceylon, China, Australia. ScAPHANDER, Montfort. Type, 8. lignarius, Pl. XIV., Fig. 12. Etymology, scaphe, boat, aner, man. Shell oblong, conyolute; spirally striated; aperture much expanded in front; spire concealed; epidermis thick ; lingual teeth 1.0.1, crested. Animal with a large oblong head, destitute of eyes; foot short and broad; lateral lobes reflected, but not enveloping the shell; gizzard with two large trigonal plates and a small narrow transyerse plate (Fig. 17). It feeds on Dentalium entale. Distribution, 13 species. United States, Norway, Britain, Mediterranean on sandy ground; 40 fathoms. Fossil, 8 species. Eocene—. Britain, France. PHILINE (Ascanius, 1762). Type, B. aperta, Pl. XIV., Fig. 13. Synonym. Bullea. Lamarck. Shell internal, white, translucent, oval, slightly convoluted, spire rudimentary. Animal pale, slug-like; mantle inyesting the shell; head 4 —_— Ee — GASTEROPODA. 319 oblong; eyeless; foot broad; lateral lobes large, but not enveloping; tongue with two or four series of sickle-shaped uncin; gizzard with three longitudinal shelly plates. Egg Fig. 138. Philine aperta.* capsules ovate, in single series on a long spiral thread; fry with a ciliated head-yeil and an operculated, spiral shell. (Loyén.) Distribution, 16 species. West Indies, Greenland, Norway, Britain, Mediterranean, Corea, Borneo. Fossil, 7 species. Eocene—. France. Sub-genus. Chelidonura, A. Adams, (Hirundella, Gray) B. hirundinaria, Quoy, Mauritius. Shell concealed; outer lip produced posteriorly into a spur; columellar:border inflected. Animal with enveloping side-lobes ; mantle with two appendages behind, like the lateral processes of Hyalaea. Doripium, Meckel. Etymology, diminutive of Doris. Synonym, Acera, Cuvier. Eidothea, Risso. Type, D. membranaceum, Meck. Mediterranean. Distribution, 3 species. South Europe. Animal oblong, truncated behind, the angles produced and dilated or filiform; head oyate-oblong, retuse in front; side- lobes expanded, wing-like; mantle inyesting a rudimentary, membranous shell. GASTROPTERON, Meckel. Type, G. Meckelii, Bl. (Clio amate, Chiaje) Mediterranean. Animal shell-less, oval, with side-lobes developed into wing- like expansions, meeting and uniting behind; cephalic disk triangular, obtuse in front, pointed behind, eyes centrally immersed; lingual teeth 5.1.5; mantle? branchial plume exposed on the right side; reproductive orifice in front of the * From a specimen dredged at Folkestone; 0, mouth; c, head, or cephalic disc, 2, side-lobes of the foot; m, mantle. The shells, and gizzard 4, are indistinctly seen through the translucent integuments, 320 MANUAL OF THE MOLLUSCA. gill, excretory opening behind it. Longitude 1, latitude 2 inches, 2 species. PuysEema, A. Adams. Shell glassy, globular, contracted in the middle and drawn out to a point in front. Distribution, 1 species. "West coast of North America. Sormetus Adansonii, Bl., is described as semi-cylindrical, with sides grooved, nead indistinct ; shell unguiform, thin, and transparent. Atlas (Peronii, Bl.), Lesueur. Head with two small tentacular lobes; body ccn- tracted in the middle; foot dilated circularly, and fringed at the margin Famity III.—APLysIaD@. Shell wanting, or rudimentary and covered by the mantle, oblong, trigonal, or slightly convoluted. Animal slug-like, with distinct head, tentacles, and eyes; foot long, drawn out into a tail behind; sides with extensive lobes, reflected over the back and shell; branchial plume con- cealed. Sexes united. APLYSIA, Gmelin. Sea Hare. Type, A. depilans, Pl. XIV., Fig. 14. Synonym, Siphonotus (geographicus) Ad. Shell oblong, conyex, flexible, and translucent, with a pos- terior slightly incurved apex. Animal oval, with a long neck and prominent back; head with four tentacles, dorsal pair ear-like with eyes at anterior lateral bases; mouth proboscidiform, with horny jaws, lingual teeth 13.1.13, hooked and serrated, about 30 rows; gizzard armed with horny spines; sides with ample lobes folding over the back, and capable of being used for swimming; gill in the middle of the back, covered by the shell and by a lobe of the mantle, which is folded posteriorly to form an excretory siphon. Distribution, 42 species. West Indies, Norway, Britain, Wediterranean, Mauritius, China. The Sea-hares are mixed feeders, living chiefly on sea-weed, but also devouring animal substances; they inhabit the laminarian zone, and oviposit amongst the weed in spring, at which time they are frequently gregarious. (Forbes.) They are perfectly harmless animals, and may be handled with impunity. When molested they discharge a violet fluid from the edge of the internal surface of the mantle, which does rot injure the skin, has but a faint smell, and changes to wine-red. | GASTEROPODA. $21 (Goodsir.) In old times they were objects of superstitious dread, on account of their grotesque forms, and the imaginary properties of their fluid, which was held to be poisonous and to produce indelible stains.* Fossil, one or two shells of the newest tertiary in Sicily haye been doubtfully referred to this genus. Sub-genus. -Aclesia (dolabrifera), Rang. Shell trapeziform. Side-lobes closely enveloping the body, leaving only a small dorsal respiratory opening, surface ornament with filaments. 9 species. East Indies. DoLABELLA, Lamarck. Type, D. Rumphu, Pl. XIYV., Fig. 15. Etymology, dolabella, a small hatchet. Shell hard, calcareous, trigonal, with a curyed and callous apex. Animal like Aplysia, with gill near posterior extremity of the body and lateral crests closely appressed, leaving only a narrow opening; ornamented with branching filaments. Distribution, 12 species. Mediterranean, Mauritius, Ceylon, Society Islands, Sandwich Islands. STYLOCHEILUS, Gould, 1841. Synonym, Aplysia longicauda Q. and G. Animal limaciform, cirrigerous, dilated at the sides, attenuated behind; neck distinct; tentacles 4, long, linear, papillose, far apart; lips dilated laterally into tentacular processes. Distribution, 3 species. New Guinea, on Fwci. DoLABRIFERA, Grube. Shell trapezoidal ; side-lobes not used for swimming. Distribution, 4 species. Indian Ocean, West America. SIPHONOPYGE, Brown. Shell truncated in front ; foot-lobes spread out for swimming; posterior part extended beyond the siphon. Distribution, 6 species. "West America, Chinese Sea. Norarcuvs, Cuvier. Type, N. Cuyieri, Bl. Etymology, notos, the back, archos, vent. Synonym, Busiris (griseus), Risso, ? Bursatella (Leachii), Bl, * Aplysia (from a and pluo) un-washable: the Aplysia of the Greek fishermen were sponges unfit for washing. Pd $22 MANUAL OF THE MOLLUSCA. Animal shell-less, ornamented with filaments, sometimes dendritic, foot narrow, lateral crests united, leaying only a narrow branchial slit ; gills not covered by an opercular mantle lobe. Distribution, 7 species. Mediterranean, Red Sea. Icarus, Forbes, 1843. Type, I. Gravesii, F’. Synonym, Lophocercus (Sieboldti) Krohn, 1847. Shell like Bullea; convoluted, thin, ovate, covered with epidermis, outer lip separated at the suture, posterior angle inflected and rounded. Animal slender, papillose; tentacles 2, ear-shaped; eyes sessile on sides of head; side-lobes reflected and partly covering the shell, united behind; tail long and pointed. LoBIGER, Krohn. Type, i. Philippii, Pl. XIV., Fig. 16. Sicily. Shell oval, transparent, flexible, slightly convoluted; covered with epidermis. Animal slender, papillose, with two flattened, oval tentacles, and minute sessile eyes on the sides of the head; shell exposed on the middle of the back, covering the plume-lke gill; sides with two pairs of rounded, dilated lobes, or natatory appendages, foot linear, tail long and slender. Distribution, 4 species. Atlantic; South Europe. FamiIty [Y.—PLEUROBRANCHIDE. Shell limpet-like or concealed, rarely wanting; mantle or shell covering the back of the animal; gill lateral, between the mantle-margin and foot; food vegetable, stomach extremely complicated. PLEUROBRANCHUS, Cuvier. Example, P. membranaceus, Pl. XIV., Fig. 17. Etymology, pleura, side, branchia, gill. Synonyms, Berthella (plumula), Bl. Oscanius (membr.), Gray. Shell internal, large, oblong, flexible, slightly convex. lamellar, with a posterior, sub-spiral nucleus. Animal oblong, convex; mantle covering the back and sides, papillated, containing spicula; foot large, separated from the mantle by a groove; gill single, free at the end, placed on the right side between the mantle and foot; orifices near the WRG: sess OO Aridi ws, GASTEROPODA: 323 base of the gill; head with two grooved tentacles, eyes at their outer bases; mouth armed with horny jaws and covered by a - broad veil with tentacular lobes. Distribution, 22 species. South America, Norway, Britain, Mediterranean, Red Sea, Ceylon. Sub-genus? Pleurobranchea, Meckel; P. Meckellii, Leve, Mediterranean. Synonym, Pleurobranchidium (maculatum), Quoy, South Australia. Mantle-margin yery narrow, not concealing the gill; dorsal tentacles ear-like, oral veil tentacu- liform. POSTEROBRANCHZA, D’Orbigny. Type, P. maculata, D’Orbigny. Coast of Chili. Animal shell-less; oval, depressed, covered by a mantle broader than the foot; foot oblong, bilobed behind; branchial plume on the left side, projecting posteriorly; reproductive orifice in front of gill, excretory behind; proboscis covered by a broad bilobed yeil; no dorsal tentacles. Runcorn, (Forbes) Hancock. Type, R. Hancocki, Forbes. Synonym, ? Pelta, Quatr. (not Beck). Animal minute, slug-like, with a distinct mantle; eyes sessile on the front part of the mantle; no tentacles; gills 3, slightly plumose, placed with the vent on the right side, at the hinder part of the back, beneath the mantle; gizzard armed; reproductive organs on the right side. Distribution on Conferve near high-water mark, Torbay. NeEpDA, H. and A. Adams. Animal shell-less; mouth terminating a proboscis, which is long and thin; oral yeil half-moon shaped, with two lateral recurved tentacles, Distribution, 1 species. South Europe. SusariA, Griibe. Shell small; mantle tuberculated, extending well over both head and foot; notched in front. Distribution, 1 species. South Europe. UMBRELLA, Chemnitz. Chinese-umbrella shell. Type, U. umbellata, Pl. XIV., Fig. 18. Synonym, Acardo, Lam. Gastroplax, Bl. Shell, limpet-like, orbicular, depressed, marked by concontri¢ 824 MANUAL OF THE MOLLUSOCA. lines of growth; apex sub-central, oblique, scarcely raised ; margins acute; inner surface with a central coloured and striated disk, surrounded by a continuous irregular muscular impression. It has a minute sinistral nucleus. Animal with a very large tuberculated foot, deeply notched in front; mouth small, proboscidiform, retractile into the pedal notch, covered by a small-lobed yeil; dorsal tentacles ear- shaped, with large plicated cavities at their bases ; eyes small, sessile between the tentacles; mantle not extending beyond the shell; gill forming a series of plumes beneath the shell in front and on the right side; reproductive organ in front of the dorsal tentacles; excretory orifice posterior, tubular. Distribution, 6 species. Canaries, Mediterranean, India, China, Sandwich Islands. Fossil, 4 species. Oolite—. United States, Sicily, Asia. TYLopINA, Rafinesque. x Type, T. punctulata, Raf. (— citrina, Joannis). 3 species. Mediterranean, Norway. Fossil, 1 species. Tertiary. Shell limpet-like, depressed, apex sub-central, with a minute spiral nucleus. Animal oblong, foot truncated in front, rather pointed | behind; dorsal tentacles ear-like, with eyes sessile at their inner bases; oral tentacles broad; branchial plume projecting posteriorly on the right side. FAMILY V.—PHYLLIDIADZA. Animal shell-less, covered by a mantle, branchial laminz arranged in series on both sides of the body, between the foot — and mantle. Sexes united. PHYLLIDIA, Cuyier. Type, P. pustulosa, Cuvier. Etymology, diminutive of phyllon, a leaf. Animal oblong, covered with a coriaceous tuberculated — mantle; dorsal tentacles clavate, retractile into cavities near the front of the mantle; mouth with two tentacles; foot broadly oval; gills forming a. series of laminz extending the entire length of both sides; excretory orifice in the middle line, near the posterior end of the back, or between the mantle and foot; reproductive organs on the right side; stomach simple, membranous. Distribution, 5 species. Mediterranean, Red Sea, India. —eSeE— le > GASTEROPODA. 32.6 FRYERIA, Grube. Excretory orifice on the side of the foot under the mantle, which is leathery and warty; 6 gills entire length of both sides. Distribution, 1 species. South Sea, East Africa. HYPoBRANCHLMA, A. Adams. Mantle cuticular; gills limited to the hinder part of the body; excretory orifices at the side, under the mantle. Distribution, 1 species. Japan. DIPHYLLIDIA, Cuyier. Type, D. Brugmansii, Cuvier. Synonym, Pleurophyllidia, Chiaje. Linguella, Bl. Animal oblong, fleshy; mantle ample; gills limited to the hinder two-thirds of the body ; head with minute tentacles and a lobe-like veil; vent at the right side, behind the reproductive orifices; lingual teeth 30.1.30. Distribution, 9 species. Norway, Britain (D. lineata, Otto), Mediterranean, India. SECTION B.—NUDIBRANCHIATA. Animal destitute of a shell except in the embryo state; branchize always external, on the back or sides of the body. Sexes united. The Nudibranchiate sea-slugs are found on all coasts where the bottom is firm or rocky, from between tide-marks to a depth of 50 fathoms; a few species are pelagic, crawling on the stems and fronds of floating sea-weed. They haye been found by Middendorff, in the Icy Sea, at Sitka, and in the sea of Ochotsk ; in the tropical and southern seas they are abundant. No satisfactory account, however, has been published of any except the European, and especially the British species, which form the subject of an admirable monograph by Messrs. Alder and Hancock, in the publications of the Ray Society. They require to be watched and drawn whilst living and active, since after immersion in spirits they lose both their form and colour. In some the back is covered with a cloak or mantle (?), which con- tains calcareous spicula of various forms, sometimes so abun- dant as to form a hard shield-like crust.* The dorsal tentacles and gills pass through holes in the cloak somewhat like the “‘key-hole” in Fisswrella. In others there is no trace of a * According to Mr. Huxley, the “cloak” of the Dorids is not the equivalent of the nantle, but “ has more relation to the epipodium ” 3826 MANUAL OF THE MOLLUSCA. mantle whatever. The eyes appear as minute black dots, immersed in the skin, behind the tentacles; they are well organised and conspicuous in the young, but often invisible in the adult. The dorsal tentacles are laminated, like the antennze of many insects (Fig. 11, p.17); they are never used as organs of touch, and are supplied with nerves from the olfactory ganglia. The nervous centres are often conspicuous by their bright orange colour; they are concentrated above the cesophagus ; three pairs are larger than the rest, the cerebroid in front, the branchial behind, and the pedal ganglia at the sides. The cerebroid supplies nerves to the tentacles, mouth, and lips. The olfactory gangla are sessile on the front of the cerebroid (in Doris), or situated at the base of the tentacles (in olis). The optic ganglia are placed on the posterior border of the cerebroid; the auditory capsules are sessile on the cerebroid, immediately behind the eyes, they contain an agglomeration of minute otolites, which are continually oscillating.* The buccal ganglia are below the cesophagus, united to the cerebroid by commissures, forming a ring; anterior to this a small ring is sometimes formed by the union of the fifth pair of nerves. The pedal ganglia (properly infra-cesophageal) are united laterally to the cerebroid and rarely meet below, but are united by com- missures which form (together with those of the branchial centres) the third ring, or great nervous collar, The branchial gangha are united behind to the cerebroid, and sometimes blend with them; they supply the skin of the back, the rudi- mentary mantle, and the gills; beneath and sessile on their front border is the single visceral ganglion. Besides this excito- motory system (which includes the great centres, or brain, and the nerves of sensation and voluntary motion), the nudibranchs possess a sympathetic system, consisting of innumerable minute ganglia, dotted over all the viscera, united by nerves forming plexuses, and connected in front with the buccal and branchial centres.f The digestive organs of the Nudibranchs present two remark- able modifications: in Doris and Z'ritonia the liver is compact * The auditory capsules of other Mollusca (excepting the Nucleobranchs) are attached to the posterior side of the pedal (sub-cesophageal) ganglia, j The sympathetic system supplies nerves to the heart and other organs which are independent of the will, and not ordinarily susceptible of pain; they are called “organic” nerves, as all the vegetative functions depend on them. Its existence in the Mollusca was first clearly demonstrated by MM. Hancock and Embleton, The ezcito- motory system of the Mollusca corresponds with the cerebro-spinal system of the | vertebrata. Ci 4g Rae ee ee GASTEROPODA. 827 and the stomach a simple membranous sac; whilst in Aolis the liver is disintegrated, and its canals so large that the process of digestion must be chiefly carried on in them, and they are regarded as ccecal prolongations of the stomach; the cceca extend into a series of gill-like processes, arranged upon Hh i Fig. 139. Dendronotus arborescens. the back of the animal, which also contain part or the whole of the true liver; the gastric ramifications vary exceedingly in amount of complexity. The Doridide are distinguished by haying a short and wide lingual membrane with numerous similar teeth; the Aolids have a narrow ribbon with a single series of larger teeth. In Dendronotus a large central tooth is flanked by a few small denticulated teeth. (Alder and Hancock, 2P L; Fic. 8.) The only Nudibranch with a solid upper jaw, is dgirus punctilucens (A. and H., Pl. XVII., Fig. 15). In other instances the two halves are articulated and act as lateral jaws. In 4Aigirus the mouth is also furnished with membranous fringes (A. and H., Pl. XVII., Fig. 14). Ancula cristata has a for- midable spinous collar (Pl. XYVII., Fig. 7). (EW ; ty \Y ) ai Ny 4 Fig. 140. a, Mouth of -2girus punctilucens. b, Horny upper mandible detached. c, Prehensile collar of Ancula, a, mantle ; z, dental sac; 8, insertion-plate of mandible ; c, passage of mouth. The yascular system and circulation of the nudibranchiate molluscs is incomplete. In Doris veins can be traced only in the liver and skin; the greater part of the blood from the arteries escapes into the visceral sinus and into a network of 328 MANUAL OF THE MOLLUSCAs sinuses in the skin, from which it returns to the auricle by two lateral veins, without having circulated through the gills. The heart is contained in a pericardium to which is attached a small ventricle, or portal heart, for impelling blood to the liver; the hepatic veins run side by side with the arteries and open into a circular vein, surrounding the vent, and supplying the gills. Only hepatic blood, therefore, circulates through the gills. In. olis there are no special gills, but the gastro-hepatic papillz are accompanied by veins which transmit blood to the auricle. The skin acts as an accessory breathing-organ; it performs the function entirely in the H/ysiade, and in the other families, when by accident the branchie are destroyed. The water on the gills is renewed by ciliary action. The fry is provided with a trans- parent, nautiloid shell, closed by an operculum, and swims with a lobed head-vyeil fringed with cilia, like the young of most other gasteropods. (Hancock and Embleton, Phil. Trans. 1852. An. Nat. Hist. 1843.) FAmIty VI.—Dorip@&.* Sea-lemons. - Animal oblong; gills plume-like, placed in a circle on the middle of the back; tentacles two; eye-specks immersed, behind the tentacles, not always visible in the adult; lingual membrane usually with numerous lateral teeth, rachis often edentulous; stomach simple; liver compact; skin strengthened with spicula, more or less definitely arranged. Dorts, L. Etymology, doris, a sea-nymph. Example, D. Johnstoni, Pl. XIII., Fig. 1. Synonyms, Dendrodoris, Eb. Hemidoris, Strp. Animal oval, depressed; mantle large, simple, covering the head and foot; dorsal tentacles 2, clavate or conical, lamellated, retrac- tile within cayities; gills surrounding the vent on the posterior part of the back, retractile into a cavity; head with an oral veil, sometimes produced into labial tentacles; mouth with a lower mandible, consisting of two horny plates, united near the front, and having 2 projecting points; lingual teeth nume- rous, central small, laterals similar, hooked and sometimes serrated, 24-68 rows; 37-141 in a row; nidamental ribbon © rather wide, forming a spiral coil of few volutions (p. 41, © Fig. 29). * Contracted from Doridide ; as the Greeks used Deucalides for Deucaliontiades, Ehrenberg divided the genus Doris into sections by the number and form of the gills, characters of only specific importance. GASTEROPODA. 329 Sub-genus. Oncidoris (Bl?). D. bilamellata, Johnst. Back elevated, tuberculose; gills non-retractile; oral tentacles fused into a veil; buccal mass with a gizzard-like appendage; lingual teeth 2 in each row. (A. and H.) D. scutigera (Villiersia), D’Orbigny, Rochelle ; has the mantle more than usually strengthened with calcareous spicula. Distribution, 100 species. The Dorids vary in length from 3 lines to more than 3 inches, they feed on zoophytes and sponges, and are most plentiful on rocky coasts, near low water, but range as low as 25 fathoms, They occur in all seas, from Norway to the Pacific. HEPTABRANCHUS, A. Adams. Mantle without a longitudinal ridge on the back; 7 gills arranged in a semicircle; oral tentacles star-shaped. HEXABRANCHUS, Ehrenberg. Same as last, but with 6 gills arranged in a cross on the hinder part of the body; oral tentacles notched. ATAGEMA, Grube. Mantle with longitudinal ridge on the back; tentacles clayate, retractile ; gills very small. Distribution, 1 species. New Zealand. AcTINocycLus, Ehrenberg. Animal ovate ; back naked; gills very plumose. Distribution, 7 species. East Africa and South Europe. CHROMODORIS. Animal almost quadrangular; back naked; feathery gills arranged lineally. Distribution, 1 species. ast India. ASTERONOTUS, Ehrenberg. een! ovate: the apertures for the gills and tentacles almost closed. Distribution, 2 species. East Africa and South Europe. GLossoporIs, Ehrenberg. Synonym, Pterodoris, Eb. Tentacles retractile; back covered with unequal cylindrical _ processes; a thread-like process on each side of the fore part of the foot. Distribution, 7 species. East India and West America. 330 MANUAL OF THE MOLLUSCA. GoNnIODORIS, Forbes. Etymology, gonia, an angle. Type, G. nodosa, Pl. XIII., Fig. 2. Animal oblong; tentacles clavate, laminated, non-retractile ; mantle small, simple, exposing the head and foot. Spawn coiled irregularly. Distribution, 26 species. Norway, Britain (2 species), Medi- - terranean, China. Between tide-marks. TRIOPA, Johnston. Type, T. claviger, Pl. XIII., Fig. 3 Synonym, Psiloceros, Menke. Animal oblong; tentacles clavate, retractile within sheaths; mantle margined with filaments; gills few, pinnate, around or in front of the dorsal vent. (A. and H.) Lingual teeth 8.1.8, or 8.0.8. Distribution, 3 species. Norway and Britain. Low water— 20 fathoms. fAciIrvS, Loyén. Type, Ai. punctilucens, Pl. XIII., Fig. 4 Etymology, ? atx (aigos), a goat. Animal oblong or elongated, covered with very large tubercles; no distinct mantle ; tentacles linear, retractile within prominent lobed sheaths; gills dendritic, placed around the dorsal vent. (A. and H.) Lingual teeth 17.0.17. Distribution, 3 species. Norway, Britain (2 species), France. Littoral zone. THECACERA, Fleming. Etymology, theke, a sheath, ceras, a horn. Type, T. pennigerum, Mont. Animal oblong, smooth; tentacles clayate, laminated, re- tractile within sheaths; head with a simple frontal veil; gills pinnate, placed round the dorsal vent, and surrounded by a row of tubercles. (A. and H.) Distribution, Britain, 2 species. Length, }—} inch. Found at low water. PoLYcERA, Cuyier. Kitymology, potycera, many horns. Type, P. quadrilineata, Pl. XIII., Fig. 5. f e Animal oblong or elongated ; tentacles laminated, non- retractile, sheathless; head-yeil bordered with tubercles or ee GASTEROPODA. sol tentacular processes; gills with 2 or more lateral appendages. (A. and H.) Distribution, Norway (8 species), Britain, Red Sea. Within tide-marks and in deep water on corallines. The spawnisstrap- shaped, and coiled on stones, in July and August. P. ocellata (Plocamophorus, Riippell) has the cephalic tentacles branched. IpAutrA, Leuckart. Hiymology, Idalia, Venus, from Mount Idalium, in Cyprus. Synonyms, Euplocamus, Phil. Peplidium (Maderze), Lowe. Example, I. aspersa, Pl. XIII., Fig. 6. Coralline zone. Animal broadly oblong, nearly smooth, tentacles clavate or linear, with filaments at their base; head slightly lobed at the sides; mantle very small, margined with filaments; lingual teeth 2.0.2. Distribution, 14 species. Norway, Britain (4 species), Medi- terranean, Madeira, Japan. ANcULA, Loyén. Synonym, Miranda, A. and H. Type, A. cristata, Alder. Animal slender, elongated; mantle entirely adnate, orna- mented with simple filaments; tentacles clavate, laminated ; with filiform appendages at their base; labial veil produced on each side. Distribution, 2 species. Norway and Britain. Length, 4 inch. CERATOSOMA. (Gray), A. Adams. Etymology, ceratois, horned, soma, body. Type, C. cornigerum, Ad. Animal oblong, narrow, with two large and prominent horn- like processes on the posterior part of the back, behind the gills; gills 5, bipinnate; dorsal tentacles clavate, laminated, rising _ from rounded tubercles, non-retractile ; head with short lateral _ processes ; foot narrow. Distribution, 2 species. Sooloo Sea. (A. Adams.) TREVELYANA, Kelaart. 1858. Body without a cloak. Two dorsal tentacles, without sheaths ; non-retractile. Mouth in front of head, without tentacles - Branchiee in a circular disk on the back, non-retractile. Distribution, 1 species (T. Ceylonica). Ceylon. 332 MANUAT. OF THE MOLLUSOA. Crimora, A. and H. Body limaciform. Cloak nearly obsolete, forming a veil with branched appendages over the head, and a papillated ridge on the sides of the back. Dorsal tentacles laminated, retractile within sheaths; oral tentacles tubercular. Branchiz plumose, non-retractile. Lingual teeth 26.0.26. PELAGELLA, Grube. Animal oblong; tentacles sheathless ; head-veil without pro- cesses; ridge along the middle of the back, and two lateral ones; 8 feathery gills arranged in a circle. Distribution, 1 species. South Europe. Gymnoporis, Steenstrup. Animal oblong; tentacles sheathless; gills, with lateral pro- cesses, dendritic, 2 or more in number. Distribution, 1 species. Japan. ACANTHODORIS, Grube. Animal oblong; tentacles sheathless; retractile within a cavity in the mantle; several fleshy processes on the back; 8 feathery non-retractile gills. Distribution, 2 species. North Sea. _CASELLA, H. and A. Adams. Tentacles retractile within sheaths; gills laminated, with 6 lobes. Distribution, 1 species. East India. BRACHYCHLAMIS, Ehrenberg. Mantle long, angular ; tentacles in front of the edge of mautle. Distribution, 1 species. Hast Africa. FAMILY VII.—TRITONIADZ. Animal with laminated, plumose, or papillose gills, arranged — along the sides of the back ; tentacles retractile into sheaths ; lingual membrane with 1 teal and numerous lateral teeth ; orifices on the right side. TRITONIA, Cuyier. Example, T. plebeia, Pl. XIII., Fig. 7. Animal elongated ; tentacles with branched filaments; veil — tuberculated or digitated ; gills in single serios on a ridge down 2 GASTEROPODA. 333 each side of the back; mouth armed with horny jaws; stomach simple, liver compact. Distribution, 13 species. Norway and Britain. Under stones at low water,—25 fathoms. 7’. Hombergii, Cuvier, found on the scallop-banks, attains a length exceeding 6 inches. Scyittama, L. Type, 8. pelagica, Pl. XIII., Fig. 8. Etymology, scyllaea, a sea-nymph. Animal elongated, compressed ; foot long, narrow, and chan- neled, adapted for clasping sea-weed; back with 2 pairs of wing-like lateral lobes, bearing small tufted branchie on their inner surfaces; tertacles dorsal, slender, with lamellated tips, retractile into long sheaths; lingual teeth 24.1.24, denticulated ; gizzard armed with horny, knife-like plates; orifices on the _ right side. Distribution, 7 species. Atlantic, South Britain, Mediter- ranean. On floating sea-weed. Nerea (punctata), Lesson, New Guinea; 10 lines long, with ear-shaped tentacles, and 3 pairs of dorsal lobes. TETHYS, L. Etymology, tethys, the sea (personified). Synonym, Fimbria, Bohadsch. Type, T. fimbriata, L., Pl. XIII., Fig. 9. Animal elliptical, depressed ; head covered by a broadly ex- _ panded, fringed disk, with 2 conical tentacles, retractile into _ foliaceous sheaths; gills slightly branched, a single row down each side of the back; reproductive orifices behind first gills, yent on right side, behind second gill; stomach simple. Distribution, 1 species. Mediterranean. Attains a foot in fength, and feeds on other molluscs and crustaceans. (Cuvier.) ? BORNELLA (Gray), A. Adams. _ Type, A. Adamsii, Gray. Length, 4 inches. Animal elongated; dorsal tentacles retractile into branched sheaths; head with stellate processes; back with two rows of _ eylindrical, branched, gastric processes, to which small dendritic gills are attached ;* foot very narrow. _ Distribution, 3 species. Straits of Sunda, on floating weed; _ Berneo, * This observation deserves further inquiry. 334 MANUAL OF THE MOLLUSCA, ? DenpDRoNoTUS, A. and H.* Etymology, dendron, a tree, notos, the back. Type, D. arborescens, Pl. XIII., Fig. 10. Animal elongated; tentacles laminated; front of the head with branched appendages; gills arborescent, in single serieg down each side of the back ; foot narrow ; lingual teeth 10.1.10; stomach and liver ramified. Distribution, 8 species. Norway and Britain. On sea-weed and corallines ; low water—coralline zone. ? Doto, Oken. Etymology, doto, a sea-nymph. Example, D. coronata, Pl. XITI., Fig. 11. Animal slender, elongated; tentacles linear, retractile into trumpet-shaped sheaths; veil small, simple; gills ovate, muri- cated, in single series down each side of the back; lingual membrane slender, with above 100 recurved, denticulated teeth, in single series; foot very narrow. The stomach is ramified, and the liver is entirely contained in the dorsal processes, which fall off readily when the animal is handled, and are soon renewed. Distribution, 4 species. Norway and Britain. On corallines in deep water—50 fathoms. ! GELLINA, Gray. Head simple ; papille or gills smooth. Distribution, 1 species. North Sea. ? MELIB@A, Rang. Type, M. rosea, Rang; on floating weed, off the Cape. Animal elongated, with a narrow, channeled foot and long, slender tail; sides of the back with 6 pairs of tuberculated lobes, easily deciduous; tentacles cylindrical, retractile into long trumpet-shaped sheaths; head covered by a lobe-like veil; sexual orifices behind right tentacle, excretory behind first gil on the right side. Distribution, 8 species. South Sea and South Africa. P LoMANOTUS, Verany. Example, L. marmoratus, Pl. XITII., Fig. 12. Synonym, Eumenis, A. and H. * This and the following genera are placed by Alder and Hancock in the family folida ; they have a ramified stomach, but their external (zoological) characte7s aoree better with Zritonia than Zolis, » ee GASTEROPODA. 335 Animal elongated, smooth; head covered with a veil; tentacies clavate, laminated, retractile into sheaths; gills filamentose, arranged along the sides of the back, on the wavy margins of the mantle; foot narrow, with tentacular processes in frent; stomach ramified. Distribution, 3 species. Britain and Mediterranean. On corallines. Famity VITI.—ASoLIDz. Animal with papillose gills (?), arranged along the sides of the back ; tentacles sheathless, non-retractile ; lingual teeth 0.1.0; ramifications of the stomach and liver extending into the dorsal papille; excretory orifices on the right side; skin smooth, with- out spicula ; no distinct mantle. AHOLIS, Cuvier. Synonyms, Psiloceros, Menke. Eubranchus, Forbes. Ampho- rina, Quatref. Type, AX. papillosa, L. Etymology, Afolis, daughter of AXolus. Animal ovate; dorsal tentacles smooth, oval, slender ; papillee simple, cylindrical, numerous, depressed, and imbricated ; mouth with a horny upper jaw, consisting of two lateral plates, united above by a ligament; foot narrow; tongue with a single series of curved, pectinated teeth ; spawn of numerous waved coils. _ Sub-genera. Flabellina, Cuvier. (Phyllodesmium, Ehr.) Body slender; dorsal tentacles laminated, buccal long; papille ‘clustered ; spawn multi-spiral. Example, E. Coronata, Pl. EXITT., Fig. 13 (also Fig. 11, p. 17). Cavolina, Brug. (Montagua, Flem.), C. peregrina. Body lan- ceolate ; tentacles smooth or wrinkled; papille in transverse, rather distant rows; spawn of 1 or 2 coils. Facelina, Griibe. Like Flabellina, but with the foot small, and the two front angular portions drawn out to a point. Distribution, 5 species. Sitka, North Sea. Coryphella, Landsborough. Like Cayolina, but with papille. arranged in groups. 4 species. _ Tergipes, Cuvier, T. lacinulata. Body linear; tentacles “smooth; papille in a single row on each side; spawn kidney- shaped. ‘Distribution, Norway, Britain (33 species). United States, editerranean, South Atlantic, Pacific. Found amongst rocks at ow water ; they are active animals, moving their tentacles con- ually, and extending and contracting their papillz; they swim 326 MANUAL OF THE MOLLUSCA. readily at the surface, inverted. They feed chiefly on sertularian zoophytes, and if kept fasting will devour each other; when irritated they discharge a milky fluid from their papille, which are very liable to fall off. GLAucvws, Forster. Etymology, glaucus, a sea-deity. Synonyms, Laniogerus, Bl. Pleuropus, Raf. Example, G. Atlanticus, Pl. XIII., Fig. 14. Animal elongated, slender ; foot linear, channeled; tentacles 4, conical; jaws horny; teeth in single series, arched and pectinated ; gills slender, cylindrical, supported on 3 pairs of lateral lobes; stomach giving off large cceca to the tail and side lobes; liver contained in the papille; sexual orifice beneath first dextral papilla, vent behind second papilla; spawn in a close spiral coil. Distribution, 7 species. Atlantic, Pacific. Found on floating sea-weed; deyours small sea-jellies, Porpite and Velelle. (Bennet.) Fiona, Alder and Hancock. Type, F. nobilis, A. and H. Synonym, Oithona, A. and H. (not Baird). Animal elongated; oral and dorsal tentacles linear; mouth armed with horny jaws; gills (?) papillary, clothing irregularly a sub-pallial expansion on the sides of the back, each with a membranous fringe running down its inner side. Distribution, 3 species. Falmouth. Under stones at low water. (Dr. Cocks.) EMBLETONIA, A. and H. Etymology, dedicated to Dr. Embleton, of Newcastle. Synonyms, Pterochilus, A. and H. ? Cloelia (formosa), Loyén. Type, KE. pulchra, Pl. XIIT., Fig. 15. Animal slender; tentacles 2, simple; head produced into a flat lobe on each side; papille simple, sub-cylindrical, in a single row down each side of the back. Distribution, 4 species. Scotland (2 species). In the littoral and laminarian zones. Calliopeea, (bellula), D’Orbigny. Brest ; has 2 rows of papille down each side of the back; cephalic lobes subulate; yent dextral. Lon. 3 lines. GASTEROPODA. 837 CautmA, Alder and Hancock. Animal sharply angular in front; foot broad; papilis simple and supported on cylindrical bases; tentacles small. Distribution, 1 species. North Sea. FAYORINUS, Griibe. Animal with slender cephalic tentacles knobbed at the extremity; oral tentacles 2 pair; papille arranged in seyeral oblique rows. Distribution, 1 species. North Sea. GALvina, Alder and Hancock. Animal with papillz in transverse rows; oral tentacles short and tapering; rounded in front. Distribution, 2 species. North Sea. CuTHoniA, Alder and Hancock. Animal with head naked and expanded ; papille clavate and arranged in thick-set rows. Distribution, 1 species. North Sea. Fiturvus, Dekker. Foot stunted; body slender; tentacles 2; mouth on a loose fringe of skin with 2 small oral feelers; papille in 2 long rows down the back. 1 species. Procronotvs, A. and H. Type, P. mucroniferus, Pl. XIII., Fig. 16. Dublin, shallow water. Synonyms, Venilia. A. and H. Zephrina, Quatref. Animal oblong, depressed, pointed behind; dorsal tentacles 2, linear, simple, with eyes at their base, behind ; oral tentacles lated, united at the base by an arched crest ; head with a small " short; head covered by a,small, semi-lunar veil; mouth with _ horny jaws; papille on ridges down the sides of the back and round the head in front; vent dorsal. Distribution, 3 species. North Atlantic. ANTIOPA, A, and H. Type, A. splendida, A. and H. Synonym, Janus, Verany. Animal ovate-oblong, pointed behind ; dorsal tentacles lamel- Q 338 MANUAL OF THE MOLLUSCA. veil and two labial tentacles; papille ovate, placed along the lateral ridges of the back and continuous above the head; vent central, posterior, sexual orifice at the right side; lingual teeth numerous. ? Distribution, 3 species. Britain, Mediterranean. HERM#A, Lovén. Type, H. bifida, Pl. XIII., Fig. 17. Norway, Britain. Animal elongated, tentacles folded longitudinally; papille rumerous, arranged down the sides of the back; sexual orifice’ below right tentacles; vent dorsal, or sub-lateral, anterior. ALDERIA, Allman. Etymology, named after Joshua Alder, one of the authors of the ‘‘ Monograph on the British Nudibranchiate Mollusca.” Type, A. modesta, Pl. XIII., Fig. 18. 38 species. Norway, South Ireland, and South Wales. Animal oblong, without tentacles; head lobed at the sides; papillzs arranged down the sides of the back; vent dorsal, posterior. ? Stiliger (ornatus), Ehrenberg; Red Sea. Vent dorsal, anterior. CHIORMRA, Gould, 1855. Animal oblong; head large, pedunculated and provided with oral cirri; papille foliaceous and arranged in two lateral rows; generative organs on the right side. C. leonina, Puget Sound. FAmity [X,—PHYLLIRHOIDA. Animal pelagic, foot-less (apodal), compressed, swimming © freely with a fin-like tail; tentacles 2, dorsal; lingual teeth in © a single series ; stomach furnished with elongated cceca ; orifices — on the right side; sexes united. PHYLLIRHOE, Péron and Lesueur. Etymology, phyllon, a leaf, rhoé, the wave. Synonym, Eurydice, Esch. Type, P. bucephala, Péron. Distribution, 6 species. Mediterranean, Moluccas, Pacific. Animal translucent, fusiform, with a lobed tail; muzzle round, truncated; jaws horny; lingual teeth 3.0.3; tentacles long and slender, with short sheaths ; intromittent organ long, bifid. GASTEROPODA. 339 FAMILY X.—ELYSIADA. Animal shell-less, limaciform, with no distinct mantle or breathing-organ ; respiration performed by the ciliated surface of the body ; mouth armed with a single series of lingual teeth; stomach central, vent median, sub-central; hepatic organs branched, extending the length of the body and opening into the sides of the stomach; sexes united; male and ovarian orifices below the right eye; female orifice in the middle of the right side; heart with an auricle behind, and traces of an arterial and venous system, eyes sessile on the sides of the head, tentacles simple or obsolete.* ELyYsIA, Risso. Type, KH. viridis, Pl. XITI., Fig. 19. Synonym, Actzeon, Oken. Animal elliptical, depressed, with wing-like lateral expan- sions; tentacles simple, with sessile eyes behind them; foot - narrow. Distribution, 8 species. Britain, Mediterranean. On Zostera and sea-weed, in the laminarian zone. Placo-branchus (ocellatus, Rang.) Hasselt, Java; described as 2 inches long, with four small tentacles; the lateral expansions much deyeloped and meeting behind, the upper surface longitudinally plaited, and forming, when the side-lobes are rolled together, a sort of branchial chamber. ACTEONIA, Quatrefages. Example, A. corrugata, Pl. XIII., Fig. 20. British Channel. Animal minute, leech-like; head obtuse, with lateral crests proceeding from two short conical tentacles, behind which are the eyes. 2 species. . . CeniA, Alder and Hancock. Type, C. Cocksii, Pl. XIIT., Fig. 21. Etymology, cenia, Falmouth. Synonym? Fucola (rubra) (Quoy). * Order Dermi-branchiata, Quatref. (Pelli-branchiata, A. and H.) M. Quatre- fages erroneously described the Elysiade as wanting both heart and blood-vessels, like the Ascidian zoophytes ; with them he associated the family lide, which he described as having a heart and arteries, but no veins, their office being performed by lacune of the areolar tissue. In both families the product of digestion (chyle) was supposed to be aérated in the gastric ramifications, by the direct influence of the surrounding water. Tothis group, which has been since abandoned, he applied the name Phlefcn- _ terata (phiebs, a vein, entera, the intestines). Q 2 840 MANUAL OF THE MOLLUSCA. Animal limaciform, back elevated, head slightly angulated, bearing two linear dorsal tentacles, with eyes at their outer bases behind. LIMAPONTIA, Johnston. Type, L. nigra, Pl. XIII., Fig. 22. Synonyms, Chalidis, Qu. Pontolimax, Cr. Animal minute, leech-like; head truncated in front, with arched lateral ridges on which are the eyes; foot linear. Distribution, Norway, England, and France, between half- tide and high-water, feeding on Conferve, in the spring and summer; spawn in small pear-shaped masses, each with 50- 150 eggs; fry with a transparent nautiloid shell, closed by an operculum. RHODOPE, Koélliker, 1847. Example, R. Veranii. Animal minute, similar to Zimapontia ? worm-shaped, rather conyex above, flat beneath ; without mantle, gills, or tentacles. Upon alge, Messina. ORDER IV.—NUCLEOBRANCHIATA. Bu.* The present order consists entirely of pelagic animals, which swim at the surface, instead of creeping on the bed of the sea. Their rank and affinities entitle them to the first place in the class; but their extremely aberrant form, and unusual mode of — progression, haye caused us to postpone their description till after that of the ordinary and typical gasteropoda. There are two families of nucleobranchiate molluscs; the firolas and carinarias, with large bodies and small or no shells, and the Atlantas, which can retire into their shells and close them with an operculum. Both animal and shell are sym- metrical, or nearly so* the nucleus of the shell is minute and dextrally spiral. ; The nucleobranchs swim rapidly by the vigorous moyements of their fin-like tails, or by a fan-shaped ventral fin; and adhere to sea-weed by a small sucker placed on the margin of the latter. Mr. Huxley has shown that these organs repre- sent the three essential parts of the foot in the most highly- developed sea-snails. The sucker represents the central part of the foot, or creeping disk (meso-podium) of the snail and whelk; the ventral fin is homologous with the anterior division of the * So called because the respiratory and digestive organs form a sort of nucleus on {ie posterior part of the back. See Fig, 141, s, 0, and Pl. XIV., Fig. 24. GASTEROPODA. 8<1 foot (pro-podium), which is very distinct in Natica (p. 235), and in Harpa and Oliva; but is only marked by a groove in Paludina and Doliwm (Fig. 87). The terminal fin (or tail of Carinaria), which carries the operculum of Atlanta, is the equivalent of the operculigerous lobe (meta-podiwm) of the ordi- nary gasteropods, such as Strombus (Fig. 76). The abdomen, or visceral mass, is small, whilst the anterior part of the body (or cephalo-therax, M. Edwards) is enormously developed. The proboscis is large and cylindrical, and the tongue armed with recurved spines. The alimentary canal of Firola is bent up at a right angle posteriorly on the dorsal side ; in Atlanta it is recurved, and ends in the branchial chamber. The heart is proso-branchiate, although in Firola the auricle is rather above than in front of the ventricle, owing to the small amount of the dorsal flexure. The nucleobranchs, and especially those without shells, ‘‘ afford the most complete ocular demonstration of the truth of Milne Edwards’s views with regard to the nature of the cir- culation in the mollusca. ‘Their transparency allows the blood- corpuscles to be seen floating in the general cavity of the body —between the viscera and the outer integument—and drifting backwards to the heart; haying reached the wall of the auricle they make their way through its meshes as they best can, sometimes getting entangled therein, if the force of the heart has become feeble. From the auricle they may be followed to the ventricle, and thence to the aorta and pedal artery, through whose open ends they pour into the tissues of the head and fin.” (Huxley.) Such delicate and transparent creatures would hardly seem to need any special breathing-organ, and, in fact, it is present or absent in species of the same genus, and even in specimens of the same species. Carinaria has fully-formed branchize; in Atlanta they are sometimes distinct, and wanting in others; in Firoloides they are only indicated by a ciliated sub-spiral band. The laryee are furnished with a shell, and with ciliated vela. (Gegenbaur.) The nucleobranchs are diccious ; some individuals (of Firola) have a leaf-like appendage, others a long slender egg-tube depending from the oyiduct, and regularly annulated.* The laryze are furnished with a shell and with ciliated vela. (Gegen- baur.) The neryous system is remarkable for the wide separation of * We can only call tomind one other example of a segmented organ in the mellusca, viz., the penniform styles of Teredo bipalmulata. 842 MANUAL OF THE MOLLUSCA. the centres. The buccal ganglia are situated considerably in front of the cephalic, and the pedal ganglia are far behind, so that the commissures which unite them are nearly parallel with ~ the oesophagus. The branchial ganglia are at the posterior extremity of the body, as in the bivalves. The eyes are hour- glass shaped, and very perfectly organised; the auditory vesicles are placed behind, and connected with the cephalic ganglia, they each contain a round otolite, which sometimes seems to oscillate. (Huxley.) FAMILY J.—FIROLIDA. Animal elongated, cylindrical, translucent, furnished with a ventral fin, and a tail-fin used in swimming; gill exposed on the posterior part of the back, or coyered by a small hyaline shell. Mouth with a circular lip; lingual membrane with few rows of teeth; central teeth transversely elongated, with 3 recuryed cusps; laterals 8 on each side, the first a transverse plate with a hooked apex, 2 and 3 sickle-shaped. * FrRouA, Peron and Lesueur. Type, ¥. Coronata, Forsk. Mediterranean. Synonym, Pterotrachzea, Forsk. Animal fusiform, elongated, with a long, slender, proboscidi- form head; fin narrowed at the base, furnished with a small sucker; tail elongated, keeled, sometimes pinnate; nucleus prominent; branchial processes numerous, conical, slender; tentacles 4, short and conical; eyes black and distinct, protected by a rudimentary eyelid; lingual ribbon oblong. The female firole haye a long moniliform oviduct. Anops Peronit, D’Orbigny, described and figured as having no head (!), was probably a mutilated Firola. ‘‘ Such specimens are yery common, and seem just as lively as the rest.” (Huxley.) Distribution, 14 species. Atlantic, Mediterranean, Pacific. Sub-genus. Firoloides, Lesueur. (Cerophora, )’Orbigny). F. Desmarestii, Les. Body cylindrical; head tapering, furnished — with two slender tentacles; nucleus at the posterior extremity of the body, with or without small branchial filaments; egg- tube regularly annulated; tail-fin small and slender, ventral. fin without a sucker. Distribution, 6 species. Atlantic; Medi- — terranean. * The genus Sagitta, Q. and G., scmetimes referred to this family, is an articulate animal (Huxley.) ; GASTEROPODA. 843 Fir 141.* Etymology, carina, a keel (or keeled vessel). Type, OC. cymbium, Desh. = C. cristatus, L., Fig. 141, Pl. XIV., Fig. 19. Shell hyaline, symmetrical, limpet-shaped, with a posterior sub-spiral apex and a fimbriated dorsal keel- nucleus minute, dextrally spiral. Animal large, translucent, granulated; head thick, cylin- drical; lingual ribbon triangular, teeth increasing rapidly in size, from the front backwards ; tentacles long and slender, eyes ‘near their base; ventral fin rounded, broadly attached, with a small marginal sucker ; tail large, laterally compressed ; nucleus pedunculated, covered by the shell, gills numerous, pinnate, projecting from beneath the shell. Distribution, 8 species. Mediterranean and warmer parts of the Atlantic and Indian Oceans. They feed on small Acalephe, and probably on the pteropoda; Mr. Wilton found in the stomach of a Carinaria two fragments of quartz rock, weighing together nearly 3 grains. Fossil, 1 species. Miocene. Turin. CARDIAPODA, D’Orbigny. Example, C. placenta, Pl. XTY., Fig. 20. Etymology, cardia, heart, pous, foot. Synonym, Carinaroides, Eyd. and Souleyet. Animal like Carinaria. Distribution, 5 species. Atlantic. Shell minute, cartilaginous ; peristome expanded and bi-lobed in front, enyeloping the spire behind. FAMILY JI.—ATLANTIDA. Animal furnished with a well-developed shell, into which it # Vig. 141. p, proboscis ; ¢, tentacles ; 5, branchie; s, shell; 7, foot; d, disc, 3844 MANUAL OF THE MOLLUSCA. can retire; gills contained in a dorsal mantle cavity: lingual teeth similar to Carinaria. Shell symmetrical, discoidal, sometimes closed by an oper- culum. ATLANTA, Lesueur. Type, A. Peronii, Pl. XTV., Figs. 21-28. Synonym, steira, Esch. Shell minute, glassy, compressed and prominently keeled; nucleus dextrally spiral; aperture narrow, deeply notched at the keel; operculum ovate, pointed, lamellar, with a minute, apical, dextrally spiral nucleus. Animal 3-lobed; head large, sub-cylindrical; tentacles conical, with conspicuous eyes behind them; yentral fin flattened, fan-shaped, furnished with a small fringed sucker; tail pointed, operculigerous. Distribution, 18 species. Warmer parts of the Atlantic, Canary Islands. Sub-genus. Oxygyrus, Benson. Synonyms, Ladas, Cantraine ; Helico-phlegma, D’Orbigny. O. Keraudrenii, Pl. XIII., Figs. 24, 25. Shell milky, narrowly umbilicated on both sides; nucleus not visible; back rounded, keeled only near the aper- ture ; body whorl, near the aperture, and keel cartilaginous; no apertural slit; operculum trigonal, lamellar. 4 species. Atlantic, Mediterranean. The Atlanta was discovered by Lamanon, who supposed it to be the living analogue of the Ammonite. The operculum of Oxygyrus (Pl. XIII., Fig. 25) is singularly like the Trigonellites (p. 182); that of Atlanta (Fig. 22) is the only example of a deatral operculum to a dextral shell (p. 207). PoRCELLIA, Léyéille. Example, P. Puzosi, Pl. XTV., Fig. 29. Shell discoidal, many-whorled ; whorls keeled or coronated ; nucleus spiral; aperture with a narrow dorsal slit. Fossil, 10 species. Upper Silurian — Trias. Britain, Bel- gium. - BELLEROPHON, Montfort. Example, B. bi-carinatus, Léy. Pl. XIV., Fig. 27. Synonym, Euphemus, M‘Ooy. Shell symmetrically conyoluted, globular, or discoidal, strong, few-whorled ; whorls often sculptured; dorsally keeled; aper- ture sinuated and deeply notched on the dorsal side. GASTEROPODA. 345 Fossil, 128 species. Lower Silurian—Carb. North America, Europe, Australia, India. The name Bucania was given by Hall to the species with exposed whorls; in B. expansus, Pl. XIY., Fig. 28, the aperture of the adult shell is much expanded, and the dorsal slit filled up. (Salter.) Bellerophina, D’Orbigny (not Forbes), is founded on the Nautilus minutus. Sby. Pl. XIV., Fig. 26, a small globular shell, spirally striated, and deyoid of septa. It is found in the gault of England and France. CYRTOLITES, Conrad. Type, C. ornatus, Pl. XTV., Fig. 30. Etymology, kurtos, curved, lithos, stone. Shell thin, symmetrical, horn-shaped or discoidal, with whorls more or less separate, keeled, and sculptured. Fossil, 13 species. Lower Silurian—Carb. North America, Europe. ? Ecculiomphalus (Bucklandi), Portlock, Pl. XIV., Fig. 31. Lower Silurian, Britain, United States. Shell thin, curved, or discoidal with few widely separate whorls, slightly unsym- metrical, keeled. Fig. 142, Maclurea Logani (Salter), L. Silurian, Canada. ? MAcLUREA, Lesueur. Named after William Maclure, the first American geologist. Shell discoidal, few-whorled, longitudinally grooved at the back, and slightly rugose with lines of growth; dextral side conyex, deeply and narrowly perforated ; left side flat, exposing the inner whorls; operculum sinistrally sub-spiral, solid with two internal projections (¢ 4), one of them beneath the nucleus, very thick and rugose. Fossil, 5 species. Lower Silurian. North America; Scotland (Ayrshire, M‘Coy). This singular shell abounds in the ‘“ Chazy” limestone of the United States and Canada; sections of it may be seen eyen in the payement of New York; but specimens are very difficult to obtain. We are indebted to Sir W. EH. Logan, of the Geological Survey, Canada, for the opportunity of a3 346 MANUAL OF THE MOLLUSCA. examining a large series of silicified specimens, and of figuring a perfect shell, with its operculum in situ. It has more the aspect of a bivalve, such as Requienia Lonsdalii (Pl. XVIII., Fig. 12) than of a spiral univalye, but has no hinge. Many of the specimens are overgrown with a zoophyte, generally on the convex side only, rarely on both sides. The Maclurea has been described as sinistral ; but its oper- culum is that of a dextral shell; so that the spire must be regarded as deeply sunk and the umbilicus expanded, as in certain species of planorbis; unless it is a case conversely parallel to Atlanta, in which both shell and operculum haye dextral nuclei. The affinities of Maclurea can only be deter- mined by careful examination and comparison with allied, but less abnormal forms, associated with it in the oldest fossiliferous rocks; its relation to Huomphalus (p. 267) is not supported by the evidence of Sir W. Logan’s specimens. CLASS III.—PTEROPODA. Turs little group consists of animals whose entire life is passed in the open sea, far away from any shelter, save what is afforded by the floating gulf-weed, and whose organisation is specially adapted to that sphere of existence. In appearance and habits they strikingly resemble the fry of the ordinary sea- snails, swimming like them by the vigorous flapping of a pair of fins. To the naturalist ashore they are almost unknown; but the voyager on the great ocean meets with them where ~ there is little else to arrest his attention, and marvels at their delicate forms and almost incredible numbers. They swarm in the tropics, and no less in Arctic seas, where by their myriads the water is discoloured for leagues. (Scoresby.) They are seen swimming at the surface in the heat of the day, as well as in the cool of the evening. Some of the larger kinds have prehensile tentacles, and their mouths armed with lingual teeth, so that, fragile as they are, they probably feed upon still smaller and feebler creatures (e.g. entomostraca). In high latitudes they are the principal food of the whale, and of many sea-birds. Their shells are rarely drifted on shore, but abound in the fine sediment brought up by the dredge from great — depths. A few species occur in the tertiary strata of England and the Continent; in the older rocks they are unknown, unless some comparatively gigantic forms (conularia and theca) hays been rightly referred to this order. ey ey eR Pe ee oe ee PTEROPODA. 347 In structure, the Pteropoda are most nearly related to the marine univalves, but much inferior tothem. Their neryous -_ganglia are concentrated into a mass below the cesophagus; they haye auditory vesicles, containing otolites; and are sensible of light and heat, and probably of odours, although at most they possess very imperfect eyes and tentacles. The true foot is small or obsolete ; in cleodora it is combined with the fins, but in Clio it is sufficiently distinct, and consists of two elements; in Spirialis the posterior portion of the foot supports an oper- culum. The fins are developed from the sides of the mouth or neck, and are the equivalents of the side-lappets (epipodia) of the sea-snails. The mouth of Pnewmodermon is furnished with two tentacles supporting miniature suckers; these organs have been compared with the dorsal arms of the cuttle-fishes, but it is doubtful whether their nature is the same.* A more certain point of resemblance is the ventral flexure of the alimentary canal, which terminates on the under surface, near the right side of the neck. The pteropods havea muscular gizzard, armed with gastric teeth; a liver; a pyloric cecum; and a contractile renal organ opening into the cavity of the mantle. The heart consists of an auricle and a yentricle, and is essentially opistho- branchiate, although sometimes affected by the general flexure of the body. The venous system is extremely incomplete. The respiratory organ, which is little more than a ciliated surface, is either situated at the extremity of the body and unprotected by a mantle, or included in a branchial chamber with an opening in front. The shell, when present, is symmetrical, glassy, and translucent, consisting of a dorsal and a ventral plate united, with an anterior opening for the head, lateral slits for long fili- form processes of the mantle, and terminated behind in one or three points; in other cases it is conical, or spirally coiled or closed by a spiral operculum. The sexes are united, and the orifices situated on the right side of the neck. According to Vogt, the embryo Pteropod has deciduous vela, like the sea- snails, before the proper locomotive organs are developed. - (Huxley.) ; From this it would appear that while the Pteropoda present some analogical resemblances to the Cephalopoda, and perma- nently represent the larval stage of the sea-snails, they are developed on a type sufficiéntly peculiar to entitle them to rank * The figures of Eydoux and Souleyet represent them as being supplied with nerves from the cephalic ganglia ; whereas the arms of the cuttle-fish, and all other parts or a of the foot in the mol/usea, derive their nerves from the pedal ganglix. (Hunisy. ) 348 MANUAL OF THE MOLLUSCA. as a distinct group ; not indeed of equal value with the Gastero- poda, but with one of its orders. This group, the lowest of the univalye or encephalous orders, makes no approach towards the bivalves or acephala. Forskahl and Lamarck indeed compared Hyalcea with Terebratula; but they made the ventral plate of one answer to the dorsal valve of the other, and the anterior cephatic orifice of the pteropodcus shell correspond with the postertor, byssal foramen of the bivalve ! Section A.—ITHECOSOMATA, Bl.* Animal furnished with an external shell; head indistinct ; foot and tentacles rudimentary, combined with the fins; mouth situated in a cavity formed by the union of the locomotive organs; respiratory organ contained within a mantle cayity. FAMILy I.—HYALEIDZ. Shell straight or curved, globular or needle-shaped, sym- metrical. Animal with two large fins, attached by a columellar muscle passing from the apex of the shell to the base of the fins; body enclosed in a mantle; gill represented by a transversely plaited and ciliated surface, within the mantle cavity, on the ventral side; lingual teeth (of Hyalea) 1.1.1, each with a strong recurved haok. HYALEA, Lamarck Etymology, hyaléos, glassy. Synonym, Cayolina, Gioeni, not Brug. Type, H. tridentata, Fig. 143. Pl. XIV., Fig. 32. Shell globular, translucent ; dorsal plate rather flat, produced into a hood; aperture contracted, with a slit on each side; posterior extremity tridentate. In H. trispinosa (Diacria, Gray) the lateral slits open into the ceryical aperture. Animal with long appendages to the mantle, passing through the lateral slits of the shell ; tentacles indistinct ; fins united by a semicircular ventral lobe, the equivalent of the posterior Fig. 143. H. tridentata | element of the foot. Distribution, 19 species. Atlantic, Mediterranean, Indian Ocean. Fossil, 5 species. Muiocene—. Sicily, Turin, Dax. * Theke, a case, soma, a body ; several of the genera have no shells. PTEROPODA. 349 CLEODORA, Peron and Lesueur. Synonyms, Clio, L. (part) not Miller. Balantium, Leach MS. Type, C. pyramidata, Pl. XIV., Fig. 33. Shell pyramidal, three-sided, striated transversely ; ventral side flat, dorsal keeled; aperture simple, triangular, with the angles produced; apex acute. Animal with rudimentary eyes; tentacles obsolete ; mantle- margin with a siphonal (?) process; fins ample, united ventrally by a rounded lobe; lingual teeth 1.1.1. The transverse bars of the gills, the heart, and other organs are yisible through the pellucid shell. In C. curvata and pellucida (Pleuropus, Esch.) the mantle is furnished with two long filaments on each side. Distribution, 12 species. Atlantic, Mediterranean, Indian Ocean, Pacific, Cape Horn. Fossil, 4 species. Miocene—. Britain. (C. infundibulum, Crag.) Sub-genus. Creseis, Rang. (Styliola, Lesueur.) C. aciculata, Pl. XTV., Fig. 34. Slender, conical, pointed, straight, or curved. Fins rather narrow, truncate, with small tentacles projecting from their dorsal edges, and rudiments of the mesopodiwm on their surface ; mantle-margin with a spiral process on the left side. M. Rang states that he has seen these pteropods clustering round floating seaweed. Distribution, 6 species (like Cleodora). CUVIERIA, Rang.* Dedicated to Baron Cuvier. Type, C. columnella, Rang, Pl. XIV., Fig. 35. Shell cylindrical, transparent; aperture simple, transversely ovate ; apex acute in the young, afterwards partitioned off, and usually deciduous. Animal with simple narrow fins, united ventrally by two small lobes; lingual teeth 1.1.1. Distribution, 4 species. Atlantic, India, Australia. Fossil, 1 species. (OC. astesana, Rang.) Pliocene, Turin. Sub-genus. Vaginella, Daud. VY. depressa, Pl. XIV., Fig. 36. Sheil oblong, with a pointed apex; aperture contracted, trans- verse. fossil, 4 species. Miocene. Bordeaux, Turin. THECA, Morris. 18435. Type, T. lanceolata. * Tnder the name of “ triptére,” MM. Quoy and Gaimard described the fragment of a pteropod, since ascertained to have been a Cuvieria 350 MANUAL OF THE MOLLUSCA. Synonyms, Creseis, Forbes.* Pugiunculus, Barr. Shell straight, conical, tapering to a point, back flattened, aperture trigonal. Length, 1-8 inches. Fossil, 40 species. Palzeozoic. North America, Britain, New South Wales. ? Permian. PTEROTHECA, Salter. Type, P. transyersa, Portlock. 38 species, Lower Silurian ; Ireland, Wales, Canada. Shell bi-lobed, transversely oval, with a dorsal keel projecting slightly at each end; ventral plate small triangular. ? CONULARTA, Miller. Etymology, conulus, a little cone. Type, C. quadrisuleata, Fig. 144. Shell four-sided, straight, and tapering, the angles grooved, sides striated transversely, apex partitioned off. Fossil, 40 species. Silurian—Carb. North America, Europe, Australia. Sub-genus. Coleoprion (gracilis), Sandberger ; Devonian. Germany. Shell round, tapering, sides obliquely striated, strize alternating along the dorsal line. Fig’ 144.t EurRyYBIA, Rang. 1827. Hiymology, Eurybia, a sea-nymph. Synonym, Theceurybia, Bronn. Example, Hi. Gaudichaudi, Pl. XIV., Fig. 37 (after Huxley). Animal globular; fins narrow, truncated, and notched at the ends, united ventrally by a small lobe (metapodium); mouth with two elongated tentacles, behind which are minute eye- peduncles and a two-lobed rudimentary foot (mesopodiwm) ; body enclosed in a cartilaginous integument, with a cleft in front, into which the locomotive organs can be retracted. Lingual teeth, 1.0.1. The animal has no proper gill, but Mr. Huxley has observed two ciliated circles surrounding the body, as in the larva of Pneumodermon. Distribution, 4 species. Atlantic and Pacific. Sub-genus. Psyche, Rang. (Halopsyche, Bronn.) P. globulosa, * Creseis Sedgwicki, Forbes, is an orthoceras with very thin septa, belonging to the saine group with (Conularia) teres, Sby. Tentacutites, Schl. is annellidous. (Salter.) j Carboniferous limestone, Brit. Belgium. £ This name had been previously employed for four different genera of plants and animals. = mee y+ PTEROPODA. 851 Pl. XIV., Fig., 38. Animal globular, with two simple oval fins. Distribution, 1 species. Off Newfoundland CYMBULIA, Peron and Lesueur, Etymology, diminutive of cymba, a boat. Type, C. proboscidea, Pl. XIV., Fig. 39 (after Adams). Sheil cartilaginous, slipper-shaped, pointed in front, trun- cated posteriorly ; aperture elongated, ventral. Animal with large rounded fins connected ventrally by an elongated lobe ; mouth furnished with minute tentacles; lingual teeth 1.1.1; stomach muscular, armed with two sharp piates. Distribution, 3 species. Atlantic, Mediterranean, Indian Ocean. TIEDEMANNIA, Chiaje. Type, T. Neapolitana, Pl. XTY., Fig. 40. Named after Fr. Tiedemann. Animal naked, transparent, fins united, forming a large rounded disk; mouth central; tentacles elongated, connate ; eye-tubercles minute. Larva shell-bearing. Distribution, 3 species. Mediterranean, Australia. Famity II.—LIMAcINIDE. Shell minute, spiral, sometimes operculate. Animal with fins attached to the sides of the mouth, and united ventrally by an operculigerous lobe; mantle-cavyity opening dorsally ; excretory orifices on the right side. The shells of the true limacinide are sinistral, by which they may be known from the fry of Atlanta, Carinaria, and most other Gasteropods. LIMACINA, Cuvier Etymology, limacina, snail-like. Synonym, Spiratella, Bl. Example, L. antarctica (drawn by Dr. Joseph Hooker), Pl. XLY., Fig. 41. Shell sub-globose, sinistrally spiral, umbilicated; whorls transyersely striated; umbilicus margined ; no operculum. Animal with expanded fins, notched on their ventral margins ; operculum lobe divided ; lingual teeth 1.1.1. Distribution, 2 species. Arctic and Antarctic Seas; gre- garious. SPIRIALIS, Hydoux and Souleyet. Heample, 8. buiimoides, Pl. XIV., Fig. 42. 302 MANUAL OF THE MOLLUSCA. Synonyms, Heterofusus, Fleming. Heliconoides, D’Orbigny. Peracle, Forbes. Seaea, Ph. Shell minute, hyaline, sinistrally spiral, globose or turreted, smooth or reticulated; operculum thin, glassy, semilunar slightly spiral, with a central muscular scar. Aninuat with narrow, simple fins, united by a simple, trans- verse operculigerous lobe ; mouth central, with prominent lips. Distribution, 12 species. Greenland and Norway to Cape Horn, Indian Ocean, Pacific. ? CHELETROPIS, Forbes. Etymology, chele, a claw, and tropis, a keel. Synonym, Sinusigera, D’Orbigny. Type, C. Huxleyi, Pl. XTV., Fig. 43. Shell dextrally spiral, imperforate, double-keeled; nucleus sinistral; aperture channelled in front; peristome thickened, reflected, with two claw-like lobes. Animal gregarious in the open sea. The species comprised in this and the following genus are young gasteropods. (See pp. 212, 225.) Distribution, 2 species. South America and South-east Australia. Another minute spiral shell may be noticed here :— MACGILLIVRAYIA, Forbes. Named after its discoverer, the naturalist to H.M.S. Rattle- anake. Type, M. pelagica, Pl. XIV., Fig. 44. Shell minute, dextrally spiral, globular, imperforate, thin, horny, translucent; spire obtuse; aperture oblong, entire; peristome thin, incomplete; operculum thin, horny, concentric, nucleus sub-external. Animal with 4 long tentacles, mantle with a siphonal process ; foot expanded, truncated in front, furnished with a float after the manner of Janthina; lingual dentition closely resembling Jeffreysia. Distribution, 3 species. Taken in the towing-net off Cape Byron, East coast of Australia, 15 miles from shore, floating, and apparently gregarious. (J. Macgillivray.) Mindoro, North Atlantic. (Adams.) PTEROPODA. 853 SECTION B.—GYMNOSOMATA, BI. Animal naked, without mantle or shell; head distinct; fins - attached to the sides of the neck; gill indistinct. FamiIty III.—Ciinz. Body fusiform ; head with tentacles often supporting suckers ; foot small, but distinct, consisting of a central and posterior lobe ; heart opistho-branchiate; excretory orifices distant, on the right side; lingual teeth (in Clio) 12.1.12, central wide, denti- culated, uncini strongly hooked and recurved. Cxio (L.),* Muller. Etymology, Clio, a sea-nymph. Synonym, Clione, Pallas. Type, C. borealis, Pl. XIV., Fig. 45. (C. caudata, L., part.) Head with 2 eye tubercles and 2 simple tentacula; mouth with lateral lobes, each supporting 3 conical retractile processes, furnished with numerous microscopic suckers; fins ovate; foot lobed. In swimming, the Clio brings the ends of its fins almost in contact, first above and then below. (Scoresby.) Distribution, 4 species. Arctic and Antarctic Seas, Norway, India. Sub-genus ? Cliodita (fusiformis), Quoy and Gaimard. Head supported on a narrow neck; tentacles indistinct. 4 species. Cape, Amboyna. PNEUMODERMON, Cuvier. Etymology, Pneumon, lung (or gill), derma, skin. Type, PR. violaceum, Pl. XIV., Fig. 47. Body fusiform ; head furnished with ocular tentacles; lingual teeth 4.0.4; mouth covered by a large hood supporting two small, simple, and two large acetabuliferous tentacles, suckers numerous, pedicillate, neck rather contracted; fins rounded; foot oval, with a pointed posterior lobe; excretory orifice situated near the posterior extremity of the body, which has small branchial processes, and a minute rudimentary shell * This name was employed by Linneus for all the Pteropoda then known; his definition is most suited to the ‘northern clio,” probably the only species with which he was personally acquainted. The first species enumerated in the Syst. Nat. is C. caudata, and reference is made to an indeterminable figure in Brown’s Jamaica, and to Marten’s account of the Spitzbergen mollusc (C. borealis). In cases like this the rule is to adopt the practice of the next succeeding naturalist who defines the limits of the group more exactly. $54 MANUAL OF THE MOLTUSCA. In the fry of Pnewmodermon the end of the body is encircled with ciliated bands. (Miller.) Distribution, 4 species. Atlantic, India, Pacific Ocean. Sub-genus? Spongiobranchea, D’Orbigny. S. Australis, Pl. XTYV., Fig. 46. Gill (?) forming a spongy ring at the end of the body; tentacles each with 6 rather large suckers. Distri- bution, 2 species. South Atlantic (Fry of Pnewmodermon ?). Trichocyclus, Eschscholtz, T. Dumerilii, Pl. XIV., Fig. 48. Animal without acetabuliferous tentacles? mouth probosidi- form; front of the head surrounded with a circle of cilia, and two others round the body. ? PELAGIA, Quoy and Gaimard. Etymology, Pelagus, the deep sea (not — Pelagia, Peron and Les.). Type, P. alba, Pl. XIV., Fig. 49. Amboyna. Animal fusiform, truncated in front, rough; neck slightly contracted ; fins small, fan-shaped. CymopocEA, D’Orbigny. Etymology, Kumodoke, a Nereid. Type, C. diaphana, Pl. XTV., Fig. 50. Animal fusiform, truncated in front, pointed behind; neck slightly contracted; fins 2 on each side, first pair large and rounded, lower pair ligulate ; foot elongated; mouth probosci- diform. Distribution, 1 species. Atlantic. CHAPTER III. CLASS IV.—BRACHIOPODA, Cuvier, 1805. (= Order Pallio-branchiata, Blainyille, Prodr. 1814.) THE Brachiopoda are bivalve shell-fish which differ from the ordinary mussels, cockles, &c., in being always cqual-sided, and never quite equivalve. Their forms are symmetrical, and so commonly resemble antique lamps, that they were called lampades, or ‘‘lamp-shells,” by the old naturalists (Meuschen, 1787, Humphreys, 1797); the hole which in a lamp admits the wick serves in the lamp-shell for the passage of the pedicle by which it is attached to submarine objects.* * The principal modifications of external form presented by these shells are givenin Vlato 15; the internal structure of each genus is illustrated in the woodcuts, which are BRACHIOPODA. 308 t The valves of the Brachiopoda are respectively dorsal and ventral; the ventral valve is. usually largest, and has a pro- minent beak, by which it is attached, or through which the organ of adhesion passes. It is sometimes perforated, as in the Terebratulidze. The dorsal, or smaller valve, is always free and imperforate. The valves are articulated by two curved teeth, developed from the margin of the ventral valve, and received by sockets in the other; this hinge is so complete that the yalyes cannot be separated without injury.* A few genera have no hinge; in Crania and Discina the lower valve is flat, the upper like a limpet; the valves of ZLingula are nearly equal, and haye been compared to a duck’s bill. (Petiver.) Ventral valve, Dorsal valve. Fig. 145, Muscular system of Terebratula.} a a, adductor-muscles; 7, cardinal-muscles; x, accessory cardinals; p, ventral pedicle-muscles; p', dorsal pedicle-muscles; z, capsular-muscles; 0, mouth; v, vent: 1, loop; t, dental socket. This and several other points of difference seem to show the propriety of adopting the proposal made by Deshayes in 1836 of dividing the Brachiopods into two great groups, the one haying articulated, the other non-articulated valves. In ths first, moreover, the valves are opened by muscles acting on the cardinal process of the dorsal valve, while in the latter the valves are opened'by the pressure of the fluid in the perivisceral cayity. This difference is accompanied by a striking variation in the the same with those in Mr. Davidson’s Introduction, and in the British Museum Catalogue. They are from original studies by the author, unless otherwise stated. * The largest recent Zerebratula cannot be opened more than + of an inch, except by applying force. + Waldhzimia Australis, Quoy. }- From a drawing by Albany Hancock, Esq. 856 MANUAL OF THE MOLLUSCA. arrangement of the muscles. The articulated group possess an anal aperture ; the unarticulated none. (Hancock.)* The valyes are both opened and closed by muscles; those which open the shell (cardinales) originate on each side the centre of the ventral valve, and converge towards the hinge- margin of the free valve, behind the dental sockets, where there is usually a prominent cardinal process. The teeth form the fulcrum on which the dorsal valve turns. The adductor muscles are four in number, and quite distinct in Crania and Discina ; in Lingula the posterior pair are combined, and in Terebratula the four muscles are separate at their dorsal terminations, but united at their insertion in the centre of the larger valye. The pedicle is fixed by a pair of muscles (each doubly-attached) to the dorsal hinge-plate, and by another pair to the ventral valve, outside the cardinal muscles.t In the Terebratulide and the other Brachiopods haying articulated valves the muscular system consists of 3 pairs of muscles which act directly on the valves, and of 3 pairs which connect the shell, and adjust it with respect to the peduncle. In the unarticulated Brachiopods, such as Lingula, the muscles are more complicated than in the former group; three pairs of protractor muscles keep the valves together, and thus compensate for the absence of the hinge and condyles, which help to form this function in the articulated group; they are so arranged as to co-operate in preventing any displacement of the valves in any direction. Hence the term sliding-muscles which they have received is inappropriate, since they prevent any sliding action. In the Lamellibranchs the sliding of the valves is admirably guarded against by means of hinges with teeth and sockets; in Brachiopods the same end is apparently obtained by means of muscles. It has, therefore, been pro- posed to substitute the term, adjustor for protractor, and retractor for sliding as applied to these muscles. The following table shows the names in general use, and those proposed by Mr. Hancock :— Names in use. Names proposed. Homologous muscles in Unarticulated brachiopods. articulated brachiopods. Ant. retractors. Ant. occlusors. Ant. occlusors. Ant. adductors, POSE: | 455 Post. occlusors. Fost. Divaricators. Accessory divaricators. * Philosophical Transactions. 1858. j The muscular system of Yerebratula presents a considerable amount of resem- blance to that of Modiola (Fig. 214); the anterior and posterior pedal muscles may be corapared to the dcrsal and ventral pedicle muscles, ‘ Ss ee FT| oo BF SOLER nt, 5h ay Age , — BRACHIOPODA. 351 Names in use, Names proposed. Homologous muscles in Unarticulated brachiopods. articulated brachiopods Cent. protractors. Cent. adjustors. 0 : ee " Exit. k Vent. adjustors. Post. retractors. Post. om Dorsal “ Capsular. Peduncular. Peduncular. Ant. parietals. Post parietals. The muscles are remarkably glistening and terdinous, except at their expanded ends, which are soft and fleshy. They are, with few exceptions, non-striated. In the posterior adductors of Waldheimia transverse striations are well displayed. Their impressions are often deep, and always characteristic ; but diffi- cult of interpretation from their complexity, their change of position, and the occasional suppression of some and combina- tion of others.* There may be considerable changes in arrange- ment of muscles without any important change in the internal structure. Thus in Waldheimia cranium there are six muscular impressions in the dorsal valve; in W. australis there are only four, the other two muscles being attached to the hinge-plate, not to the valve. The valve and hinge-plate are never found together, and it is, therefore, probable that in the fossil species, the shells of which are found without hinge-plates, the muscles may have been arranged as in W. cranium. On separating the valves of a recent Terebratula, the diges- tive organs and muscles are seen to occupy only a very small space near the beak of the shell, partitioned off from the general cavity by a strong membrane, in the centre of which is placed the animal’s mouth. The large cavity is occupied by the fringed arms, which have been already alluded to (p. 5) as the characteristic organs of the class. Their nature will be better understood by comparing them with the lips and labial tentacles of the ordinary bivalves (pp. 18, 21, and Fig. 208, p,p) ; they are, in fact, lateral prolongations of the lips supported on muscular stalks, and are so long as to require being folded or coiled up. In Rhynchonella and Lingula the arms are spiral and separate; in Terebratula and Discina they are only spiral at the tips, and are united together by a membrane, so as to form a lobed disk. It has been conjectured that the living animals haye the power of protruding their arms in search of food; but this supposition is unlikely, since in many genera they are supported by a brittle skeleton of shell, while the * Professor King has shown that the compound nature of a muscular impression is often indicated by the mode in which the vascular markings proceed from it (as in Figs. 176, 181) 358 MANUAL OF THE MOLLUSCA. food is obtained by means of currents created by cilia, Lingula may have the power of slightly extending the arms. The internal skeleton consists of two spiral processes in the Spiriferide (Fig. 168), whilst in Terebratula and Thecidiwm it takes the form of a loop, which supports the brachial mem- brane, but does not strictly follow the course of the arms. The mode in which the arms are folded is highly characteristic of the genera of Drachiopoda ; the extent to which they are sup- ported by a calcareous skeleton is of less importance, and lable to be modified by age. That margin of the oral arms which answers to the lower lip of an ordinary bivalve, is fringed with long filaments (cirri), as may be seen even in dry specimens of recent Terebratule. In some fossil examples the cirri themselves were supported by slender processes of shell ; * they cannot, therefore, be yvibratile organs, but are probably themselves covered with microscopic cilia, like the oral ten- tacles of the ascidian polypes (cilio-brachiata of Farre). The anterior lip and inner margin of the oral arms is plain, and forms a narrow gutter along which the particles collected by the ciliary currents may be conveyed to the mouth. The object of the folding of the arms is obyiously to give increased surface for the disposition of the cirri. The mouth conducts by a narrow cesophagus to a simple stomach, which is surrounded by the large and granulated liver; the intestine of Lingula is reflected dorsally, slightly conyoluted, and terminates between the mantle lobes on the right side (Fig. 202). In Orbicula it is reflected ventrally, and passes straight to the right, ending as in Lingula. In Terebra- tula, Rhynchonella, and probably all the articulated Brachiopoda, the intestine is simple and reflected ventrally, passing through a notch or foramen in the hinge-plate, and ending behind the ventral insertion of the adductor muscle (Fig. 145, v.)+ The circulatory system is far less complex than was formerly supposed, and does not differ greatly from the same system in the Tunicata. The heart is placed on the dorsal surface of the stomach, and consists of a simple, unilocular, pyriform yesicle without any auricle. From it the blood is propelled through | * Spirifera rostrata and Terebratula pectunculoides, in the British Museum. “2g j The position at which the intestine terminates in the Terebratule and Rhyn- — chonelle, seems to necessitate the escape of the feces by the umbonal opening; in — these extinct genera which have the foramen closed at an early age, there is still am _ opening between the valves (e. g. in Uncites) which has been mistaken for a byssal — notch. Mr. Hancock has carefully dissected several species of these genera without — detecting any anal aperture. Filling the intestines with injections was tried, but no outlet could be discovered. 4 wl BRACHIOPODA. 359 four channels to the organs of reproduction and to the mantle ; and its flow is probably assisted by a number of subsidiary pulsatile vesicles situated on the main arterial trunks. It then courses through the plexus of Jacunes in the pallial sinuses and lobes ; turns back through the lacunes of the parietes into the system of visceral lacunes. It probably enters the liver, and ultimately finds its way back into the heart through the branchio-systemic vein. There is, however, another and more important blood current, which traverses the whole length of the brachial canal, and penetrates to the extremities of the cirri, before it joins the current returning from the visceral lacunes and flows with it into the branchio-systemic vein. The blood which has passed through the brachial canal is far more highly oxygenated than the blood which has flowed through the pallial membranes. There seems to be strong evidence that the so-called arms are really the gills or respira- tory organs of the mollusc. They also serve to bring food to the creature’s mouth by the means before noticed. The mantle is an accessory breathing-organ. It attains its highest development: as such in Lingula, but even in this genus the brachial apparatus performs the chief part in oxygenating the blood. There is another system of canals which take their rise from the yisceral cavity. What its function is has not been deter- mined; it is not the blood system as was formerly imagined, and has no connection with it. The perivisceral cavity and the visceral lacunes which diverge from it may, it is thought, be homologous to the water-yascular system in Polyzoa, the function of which is probably to evacuate the effete nitro- genised products which have been eliminated from the blood. Consequently it would perform the offices both of the kidney and the renal organs. The generative organs occupy the great pallial sinuses, and probably both sexes are combined in one individual. In the articulated Brachiopods the ovaries and testes are placed in the mantle; but in Lingula and Discina they occur in the peri- visceral chamber. The ova escape into the oviducts (regarded _ by Cuvier and others as hearts), which open externally, and haye nothing to do with the vascular system. In Rhynchonella _ there are four oviducts, but in most, if not all the other _ Brachiopods, there are only two. In Terebratulidee they are _ diyided into two portions, called the auricle and ventricle by Y Professor Owen. Mature eggs have been found in large numbers in the periyisceral chamber and in the oyiducts. Recent 360 MANUAL OF THE MOLLUSCA. Discine often haye minute fry attached to their valves, and Mr. Suess, of Vienna, has noticed a specimen of the fossil Stringo- cephalus, which contained numerous embryo shells. As yet we know little respecting the development of the Brachiopoda, but there can be no doubt that in their first stage they are free and able to swim about until they meet with a suitable position. It is probable that in the second stage they all adhere by a byssus, which in most instances becomes con- solidated, and forms a permanent organ of attachment. Some of the extinct genera (e.g. Spirifera and Strophomena) appear to have become free’ when adult, or to have fixed themselves by some other means. Four genera, belonging to very distinct families, cement themselves to foreign objects by the substance of the yentral valve. The neryous system exhibits a state of development but little superior to what is found in Ascidians. No special organs _ of sense have been detected. The red spots in the mantle, sup- posed by some to be rudimentary eyes and ears, are probably the glands situated at the base of the setze. The Lamp-shells are all natives of the sea. They are found hanging from the branches of corals, the under sides of shelying rocks, and the cavities of other shells. Specimens obtained from rocky situations are frequently distorted, and those from stony and gravelly beds, where there is motion in the waters, haye the beak worn, the foramen large, and the ornamental sculpturing of the valves less sharply finished. On clay beds, as in the deep clay strata, they are seldom found; but where the bottom consists of calcareous mud they appear to be very abundant, mooring themselves to every hard substance on the sea-bed, and clustering one upon the other. Some of the Brachiopoda appear to attain their full growth in a single season, and all probably live many years after becoming adult. The growth of the valves takes place chiefly at the margin ; adult shells are more globular than the young, and aged specimens still more so. The shell is also thickened by the deposit of internal layers, which sometimes entirely fill the beak, and every portion of the cayity of the interior which is not occupied by the animal, suggesting the notion that the creature must haye died from the plethoric exercise of the cal- cifying function, converting its shell into a mausoleum, lke 4 many of the ascidian zoophytes. a EE ee Te SS a ee ee eT ee The intimate structure of the shell of the Brachiopoda has — been investigated by Mr. Morris, Professor King, and more — recently by Dr. Carpenter; according to this last observer, — 4 BRACHIOPODA., 361 it consists of flattened prisms of considerable length, arranged parallel to each other with great regularity, and obliquely to the surfaces of the shell, the interior of which is imbricated by their out-crop (Fig. 146). This struc- ture is found only in the Rhynchonellide; WS but im most—perhaps all the other : hw Brachiopoda*—the shell is traversed by canals from one surface to the other, nearly vertically, and regularly, the dis- tance and size of the perforations varying with the species. Their external orifices are trumpet-shaped, the inner often very small; sometimes they bifurcate towards the exterior, andin Craniathey become aborescent. The canals are occupied by ccecal processes of the outer mantle-layer,t and are covered oxternally by a thickening of the epidermis. Mr. Huxley has suggested that these cceca are analogous to ‘the vascular processes by which in many ascidians the tunic adheres to the test; the extent of which adhesion varies in closely allied genera. The large tubular spines of the Produc- tide must have been also lined by prolongations of the mantle; but their development was more probably related to the main- tenance of the shell in a fixed position, than to the internal economy of the animal. (King.) Dr. Carpenter states that the shell of the Brachiopoda generally contains less animal matter than other bivalyes ; but that Discina and Lingula con- sist almost entirely of a horny animal substance, which is laminar, and penetrated by oblique tubuli of extreme minute- ness. He has.also shown that there is not in these shells that distinction between the outer and inner layers, either in struc- ture or mode of growth, which prevails among the ordinary bivalves ; the inner layers only differ in the minute size of the perforations, and the whole thickness corresponds with the outer layer only in the Lamellibranchiata. The loop, or brachial processes, are always impunctate. Mr. Hancock’s researches would tend to show that these conclusions are gene- _ rally correct, but not entirely so. ‘‘ When the shell is dissolved Fig. 146. Zerebratula. * The fossil shells of the older rocks are so generally pseudomorphous, or partake of e metamorphic character of the rock itself, that it is dificult to obtain specimens in 4 state fit for microscopic examination. _ 7 Called the “lining membrane of the shill,” by Dr. Carpenter. (Davidson Intr. : Mon. Brach.) M. Queckett states that the perforations are closed externally by disks, _ surrounded by radiating lines, supposed to indicate the existence of vibratile cilia in the living specimens. R 862 MANUAL OF THE MOLLUSCA. f in acid the free border [of the mantle] which projects beyond the marginal fold, and which is apphed to the extreme edge of the shell, can be examined with advantage. The pallial cceca are then completely exposed appended to the membrane in yarious stages of development, and the spaces between them are found studded all over with rather large, clear, oval, cell-like spots, which are arranged with consider able reoularity i in rows, so that those in the approximate rows alternate. These spots apparently correspond to the bases of the prismatic columns of the shell; and if it be allowed that they represent spaces in which cal- -careous granules had been accumulated, it is easy to understand how the fibrous or columnar structure is formed. A succession of layers of such accumulated granules deposited one after the other would result in the peculiar shell formation of the Brachicpoda.” The extremities of the prisms are not visible on the external surface, but in the young individual of some — species, as Jerebratula caput-serpentis, there is a thin layer of calcareous matter, which seems to show that in some Brachio- pods the shell is composed of two layers of shell, haying a different structure, as in the case of the Conchifera. Of all mollusca the Brachiopoda enjoy the greatest range both of climate, and depth, and time; they are found in tropical and polar seas, in pools left by the ebbing tide, and at the ereatest depths hitherto explored by the dredge. At present only 84 recent species are known; but many more will probably be found in the deep sea, which these shells mostly inhabit. The number of living species is already greater than has been discovered in any secondary stratum, but the vast abundance of — fossil specimens has made them seem more importantthan the living types, which are still rare in the cabinets of: collectors, though far from being so in the sea. Above 1,800 extinct species “of Brachiopoda have been described, of which more than half are found in England. They are distributed throughout all the sedimentary rocks of marine origin from the Cambrian strata upwards, and appear to have abtemied their maximum of specific development in the Silurian age.* Some species (like Atrypa — reticularis) extend through a whole ‘‘ system” of rocks, and — abound equally in both hemispheres; others (like Spirifera— striata) range from the Cordillera to the Ural mountains. One recent Terebratula (caput-serpentis) made its appearance in the Miocene Tertiary; whilst others, scarcely distinguishable from * The number of Silurian species amounts to 690; but these were not all living at one time, they were obtained from a whole series of deposits, representing a succession yf periods. g BRACHIOPODA 863 it, are found in the Upper Oolite and throughout the Chalk series and London Clay.* FAMILY I.—TEREBRATULIDA. Shell minutely punctate; usually round or oyal, smooth or striated; ventral valye with a prominent beak and two curved hinge-teeth ; dorsal valve with a depressed umbo, a promi- nent cardinal process between the dental sockets, and a slender shelly loop. Animal attached by a pedicle, or by the ventral valves; oral arms united to each other by a membrane, variously folded ; sometimes spiral at their extremities. Fig. 147. Terebratula vitrea, Born. TEREBRATULA, (Llhwyd.) Brug. Lamp-shell. Etymology, diminutive of terebratus, perforated. Synonyms, Lampas, Humph. Gryphus, Muhlfeldt. Epithyris, Phil. Types, T. maxillata, Pl. XV., Fig. 1. (= Ter. minor-sub- rubra, Llhwyd. Anomia terebratula, an ) 'T. vitrea, Fig. 147, Shell smooth, convex; beak truncated and _ perforated ; foramen circular; deltidium of two pieces frequently blended ; loop very short, simple, attached by its crura to the hinge-plate (Fig. 147, A). Animal attached by a pedicle ; brachial disk tri-lobed, centro lobe elongated and spirally convoluted (Fig. 147, B). The young of 7’. diphya (Pygope of Link) has bi-lobed valves (Pl. XV., Vig. 2); when adult the lobes unite, leaying a round hole through the centre of the shell. * The author has to acknowledge his obligation to Mr. Davidson for the use of the notes, drawings, and specimens, assembled during the preparation of his great work on the “ British Fossil Brachiopoda,’ printed for the Paleontographical Society; to which work the student is referred for more copious descriptions and illustrations. R2 7 364 MANUAL OF THE MOLLUSCA. Distribution, 3 species. Mediterranean 90—250 fathoms on nullipore mud. (Forbes.) Vigo Bay; Falkland Islands. Fossil, 126 species. Devonian—. World-wide. Sub-genera. Terebratulina (caput-serpentis), D’Orbigny. (Pl XY., Fig. 3.) Fig. 148. Shell finely Loe auriculate, Fig. 148. Dorsal valve. Animal, 2. deltidium usually rudimental; foramen incomplete; loop short, rendered annular in the adult by the union of the oral processes. Distribution, 6 species. United States, Norway, Cape, Japan. 10—120 fathoms. Fossil, 22 species. Oxfordian—. United States. Europe. Waldheimia (australis), King. Pl. XYV., Fig. 4 (p. 5, Figs. 5, 6), Figs. 145, 149, 150. Fig. 149. Dorsal valve. Fig. 150. Ventral valve. “Fig. 149. 7, cardinal process; t’, dental sockets; p, hinge-plate; s, septum ; ¢, cruia 4 of the loop ; /, reflected portion of the loop ; m, quadruple abductor-impression. Fig. 150. f, foramen ; d, deltidium; ¢, teeth; a, single abductor impression; 7, car- dinal muscles; z, accessory muscles; p, pedicle muscles ; v, position of the vent; z attachment of Desile-elesth. ] Shell smooth or plaited, dorsal valve frequently impressed; foramen complete ; loop elongated and reflected; septum (s) of © smaller valve elongated. Distribution, 9 species. Norway, Jaya, Australia, California, Cape Horn. Low water —100 BRACHIOYODA. 368 fathoms. fossil, 90 species. Carb—. South America, Europe. Ludesia (cardium), King, includes 1 recent and 6 fossil species which are sharply plaited. 7. impressa (Pl. XV., Fig. 5) 1s the type of a group which has the external shape of Terebratella. Meganteris, Suess, 1856. Terebratula Archiaci, Vern. Devo- nian, Asturias. Shell with a long, reflected, internal loop. TEREBRATELLA, D’Orbigny. Type, T. dersata, Gmel. (= Magel- lanica, Chemn.) Pl. XV., Fig. 7. Fig. 151. Shell smooth or radiately plaited ; dorsal valve longitudinally impressed; hinge- line straight, or not much curved; beak with a flattened area on each side of the deltidium ; foramen large; deltidium in- complete; loop attached to the septum (s). Animal like Terebratula ; the spiral lobe of the brachial disk becomes very diminutive in some species, and is obseletein Morrisiaand 7. Cumingit. Distribution, excluding sub-genera, 25 species. Cape Horn, Valparaiso (90 fathoms), New Zealand, Japan, Ochotsk, Spitzbergen, Labrador. Fossil, 16 species. Lias—. United Fig. 152. Ter. Evansit, Dav. States, Europe. In Z. crenulata and Hvansii (Fig. 152) the dorsal septum sometimes projects so far as to touch the oppo- site valye, but in other examples it remains undeveloped. (Dayidson.) Sub-genera. Trigonosemus (elegans), Konig. Synonyms, Del- thyridzea (pectiniformis), M‘Coy. Fissirostra, D’Orbigny. Example, T. Palissii, Pl. XV., Fig. 8. Shell finely plaited, beak prominent, curved, with a narrow apical foramen ; cardinal area large, triangular; deltidium solid, flat; cardinal process very prominent. Distribution, 5 species. Chalk, Europe. Lyra (Meadi), Cumberland, Min. Con. 1816. Pl. XY., Fig. 6. Synonyms, Terebrirostra, D’Orbigny. Rhynchora, Dalman.* * The name Rhynchora was given by Dalman to the Ter. costata. Wahl. = T. pectinata, L.) on the supposition that it was identical with Sowerby’s 7. Lyra; and as no specimen could be found with a long beak, an artificial one was manufactured for it, of which there is a cast in the British Museum. The second species of “‘ Rhyn- chora,” Jer. spatulata, Wahl., has no beak whatever: in shape it is like an Argiope, but measures an inch each way. The ventral valve is a simple bent plate with the teeth at the angles ; the dorsal valve is flat, with a very wide hinge-plate, and sockets _ %t the angles, whilst a single septum projects from the centre, with portions of a loop attached, 866 MANUAL OF THE MOLLUSCA. Shell ornamented with rounded ribs; beak very long, divided lengthwise internally by the dental plates; loop doubly attached? Distribution, 4 species cretaceous. Europe. Three species of similar form are found in the Trias of St. Cassian. Magas (pumila), Sby. Fig. 158. Shell smooth, conspicuously punc- ~\\2 tate, dorsal valve impressed, fora- men angular, deltidium rudimen- tary; internal septum (s) prominent, touching the ventral valve; reflected portions of the loop disunited (/). Fig. 153. M, Pumila.2 3 species. U. Green-sand—Chalk. Europe. Distribution, 2 species. New Zealand; Canaries. The recent Ver. Cumingii, of New Zealand, resembles ouchardia externally, but has the diverging processes of the loop as in Magas. 0 Fig. 154. B. Tulipa, Bl.* Bouchardia (tulipa), Davidson, Fig. 154. Beak prominent, with a minute apical foramen (/); deltidium blended with the Animai. 4° Fig. 155. Dorsal valve. shell (d) ; apophysis anchor-shaped, the septum (s) being fur- * The rauscular impressions in Bouchardia have been compared with those of Ter. Cumingii, of which the animal is known. The large impressions (7) in the disk of the ventral valve appear to be formed by the cardinal muscles; a, by the adductor; p, by fhe pedicle muscles. ‘ t Fig. 155. c, loop; f, pedicle notch; o, the ovaries. From the originals in Mr, Davidson's collection ; magnified ten diameters. Oe ee BRACHIOPODA. 367 nished with two short lamelle. Distribution, 3 species. Brazil, 13 fathoms. New Zealand, South Australia. Morrisia (anomioides, Scacchi), Dayidson. Fig. 155. Shell minute, conspicuously punctate; foramen large, encroaching equally on both yalves; hinge area small, straight; loop not reflected, attached to a small forked process in the centre of the valve. Animal with sigmoid arms, destitute of spiral termina- tions; cirri in pairs. Distribution, 3 species. Mediterranean. 95 fathoms. (Forbes.) ossi/, 4 species. Chalk—. Europe. Fig. 156. Dorsal valve with animal.2 Fig. 157. Dorsal valve. Kraussia (rubra), Day. Cape. Fig. 157. IK. Lamarckiana, Day. Australia. Fig. 156. Shell transversely oblong; hinge- line nearly straight; beak truncated, laterally keeled; area flat; foramen large, deltidium rudimentary; dorsal valve longitudinally impressed, furuished inside with a forked pro- cess rising nearly centrally from the septum; interior often strongly tuberculated. The apophysis is sometimes a little branched, indicating a tendency towards the form it attains in Fig. 158. Animal with rather small oral arms, the spiral lobe very diminutive. Distribution, 6 species. South Africa, Sydney, New Zealand; low water to 120 fathoms. Animal. Fic. 158. Dorsal valve. ? Megerlia (truncata), King, 1850. Pl. XV., Fig. 9. Fig. 158. Loop trebly attached ; to the hinge-plate by its crura, and to the septum by processes from the diverging and reflected portions of the loop. Distribution, 3 species. Mediterranean, Philippines. These species belong to the same natural group with Kraussia. Fossil, 7 species. Chalk—. 268 MANUAL OF THE MOLLUSCA, ? Ringena (lima), Day. Cretaceous, Europe, Guadaloupe, Valves spinulose ; loop trebly attached. 5 2 Pe 3 Fig. 159. Ter. (Kingena) lima, (after Davidson.) #, dental sockets ; /, cardinal process; c, crura; d, diverging processes of loop, 7, re- flected portion ; e, third attachment of loop; s, dorsal septum. ? Zsmenia (pectunculus), King. Coral rag, Hurope. Valves ornamented with corresponding ribs; loop trebly attached. ? Waltonia (Valenciennei), Dav., New Zealand. Perhaps the fry of Ter. rubicunda, with the reflected part of the loop wanting. Zellania (Davidsoni), Moore, 1855. (Ltymology, Zella, a lady’s name?) Shell minute, orthi-form; texture fibrous; hinge- area short, foramen angular, encroaching on both valves; interior of dorsal valve as in Thecidiwm, with a single central septum and broad margin. Jossil. Lias—Great Oolite. 3 species. Britain. Fig. 160. Argiope decoliata. * Fig. 161. A. Neapolitana, Sc.* # ARGIOPE, Eudes Deslongchamps. Etymology, Argiope, a nymph. Synonym, Megathyris, D’Orbigny. 4 Type, A. decollata, Pl. XV., Fig. 10. Fig. 160, 162. “a Shell ‘minute, transversely oblong or semi-oyate, smooth or * interior of dorsal valves magnified, from the originals in Coll. Davidson. ~ | : { : 1 J | 5 : BRACHIOPODA. 3869 with corresponding ribs; hinge-line wide and straight, witha narrow area to each yalye; foramen large, deltidium rudi- mentary; interior of dorsal valve with one or more prominent, sub-marginal septa; loop two or four-lobed, adhering to the septa, and more or less confluent with the valve vit \ Sy — — =\ es Lb» \ Ni \ } J A’ WAYS \ a sVid y f YS y Di iG Pay V\ Fig. 162. A. decollata, *,° ; dorsal valve with the animal, from a specimen dredged by Professor Forbes in the Avgean. The oral aperture is seen in the centre of the disk. Animal with oral arms, folded into two or four lobes, united by membrane, forming a brachial disk fringed with long cu7T1; mantle extending to the margins of the yalyes, closely adherent. Distribution, 5 species. North Britain, Madeira, Canaries, Mediterranean. 30—105 fathoms. Fossil, 19 species. Oolite—. Hurope. G hes ; ee a WE pak, Uf My, ‘ S Ne) \i ae = ean Fgh i , Fig. 163. ZT. radians, Fig. 164. 7. Mediterraneum.* : THECIDIUM, Defrance. Ktymology, Thekidion, a small pouch. Type, T. radians, Pl. XV., Fig. 11. Shell small, thick, punctate, attached by the beak; hinge- * Dorsal valve with the animal, magnified, Coll. Davidson. a) 370 MANUAL OF THE MOLLUSCA. area (h) flat; deltidium (d) triangular, indistinct; dorsal valve (Fig. 163) rounded, depressed; interior with a broad granulated margin; cardinal process prominent, between the dental sockets ; oral processes united, forming a bridge over the small and deep visceral cavity; disk grooved for the reception of the loop, the grooves separated by branches from a central septum; loop often un- symmetrical, lobed, and united more or less intimately with the sides of the grooves; ventral valve (Fig. 165) deeply excavated, hinge-teeth pro- minent; cavities for the adductor (a) and pedicle muscles (p) small; disk occupied by two large smooth impressions of the cardinal muscles, bordered by a vascular line. Fig. 165. T.radians. 4, Animal (Fig. 164) with elongated oral arms, folded on themselves and fringed with long cirri; mantle extending to the margin of the valves and closely ad- herent: epidermis distinct. ; ZT’. radians is the only unattached species, it is supposed to be fixed by a pedicle when young. (D’Orbigny.) Dorsal valve. Fig. 166. Profile.* a, adductor; c, crura; 7, loop; 7, cardinal process; p, hinge-plate; s, dorsal septum ; v s, ventral septum ; ¢, dental sockets. T. hieroglyphicum, Pl. XV., Fig. 12, has a very complicated ® Tho loop (which was discovered by Professor King) has a distinct suture iu ths BRACHIOPODA. 871 . interior ; whilst in several others there are but two brachial lobes. The Liassic species form the subject of a monograph by M. Eudes Deslongchamps; they are often minute, and attached in numbers to sea-urchins, corals, and terebratule. Distribution, 1 species. Mediterranean. Fossil, 34 species. Trias—. Europe. ? STRINGOCEPHALUS, Defrance. Etymology, Strinx (stringos), an owl, cephale, the head.* Type, S. Burtini, Pl. XV., Fig. 18. Figs. 166, 167. Devonian, Europe. Shell punctate; sub-orbicular, with a prominent beak; ventral valve with a longitudinal septum (vs) in the middle; hinge- area distinct ; foramen large and angular in the young shell, gradually surrounded by the deltidium, and rendered small and oyal in the adult; deltidium composed of three elements ; teeth prominent; dorsal valve depressed, cardinal process (7) very promi- nent, sometimes touching the opposite valve, its extremity forked to receive the ventral septum (vs); hinge-plate (p) sup- porting a shelly loop, after the manner of Argiope. Famity II.—SPIRIFERIDZ. Shell furnished internally with two calcareous spiral processes (apophyses) directed outwards towards the sides of the shell, and destined for the support of the oral arms, which must haye been fixed immoyably; the spiral lamellze are sometimes spinulose, indicating the existence of rigid cirri, especially on the front of the whorls; valves articulated by teeth and sockets. SPIRIFERA, Sowerby. Type, S. striata, Sby., Fig. 168. Synonyms, Trigonotreta. Konig. Choristites, Fischer. Del- thyris, Dalman. “Martinia, &c., M‘Coy. middle ; the dotted lines proceeding from its inner edge are added from a drawing by M. Suess, and represent what he regards as shelly processes for supporting a mein- branous disk. They may be portions of spirals, whose outer whorls are confluent. * Internal casts of Productus giganteus are called “ owl-heads” by quarrymen in the North of Engand. (Sowerby.) + Fig. 167. Young shell, magnified four diameters; A, hinge area; 6, deltidium; p, pseudo-deltidium. 872 MANUAL OF THE MOLLUSCA. Shell impunctate,* transversely oval or elongated, tri-lobed, beaked, bi-conyex, with a dorsal ridge and yentral furrow; — hinge-line wide and straight; area moderate, striated across; foramen angular, open in the young, afterwards progressively — 4 -@ Ly, NARS - 7) AYSs * \\S \ : { u 4 Dorsal valve. Fig. 168. Ventral valve. ; closed ; ventral valve with prominent hinge-teeth, and a central ~ muscular scar, consisting of the single adductor flanked by two cardinal impressions ; dersal yalye witha small cardinal process, a divided hinge-plate, and two conical spires directed outwards and nearly filling the cavity of the shell; crura united by an oral loop. The shell and spires are sometimes silicified in lime- stone, and may be developed by means of acid. In S. mosquensis the dental plates are prolonged nearly to the front of the ventral — valve. Distribution, 220 species. Lower Silurian—Trias. Arctic — America—Chili, Falkland Islands, Europe, China, Thibet, — Australia, Tasmania. Jn China these and other fossils are used — as medicine. Sub-genera. Spiriferina, D’Orbigny. S. Walcotti, Pl. XV., — Fig. 14. Shell punctate, external surface spinulose; foramen ~ covered by a pseudo-deltidium ; interior of ventral valve with a prominent septum, rising from the adductor scar. Distribution, 29 species. Carb.—Lower Oolites. Britain, France, Germany, © South America. Cyrtia, Dalman. OC. exporrecta, Pl. XV., Fig. 15. Shell impunctate, pyramidal, beak prominent, area equiangular, deltidium with a small tubular foramen. Jossil, 10 species. Silurian—Trias. Europe. In C. buchii, heteroclyta, calceola, &e., the shell is punctate. . Suessia (imbricata), Eudes Deslongchamps, 1855. (Dedicated to M. Suess). Shell like Spirifera ; texture fibrdas: hinge area wide as the shell; foramen deltoid; large valve with two cardinal septa, and a prominent central septum, supporting a little plate ; small valve with a tri-lobed cardinal process, and * Professor King attributes this to metamorphism; S. Demarlii, Bouche aan { re ; Devonian limestone, i is punctate. (Carpenter.) BRACHIOPODA. 373 a broad 4-partite hinge-plate, with processes from the outer angles of the dental sockets; crura of the spires united bya transverse band supporting a small process. fossil, 2 species. Upper Lias, Normandy. ATHYRIS, M‘Coy. Litymology, a, without, thuris, a door* (i.e. deltidium). Synonyms, Spirigera, D’Orbigny. Cleiothyris, King (not Phil.), Types, A. concentrica, Buch. A. Roissyi, Figs. 169, 170. A. lamellosa, Pl. XV., Fig. 16. Shell impunctate, transyersely oval, or sub-orbicular, bi- conyex, smooth, or ornamented with squamose lines of growth, sometimes developed into wing-like expansions (Fig. 170t); Cy A \z fj," ‘ Off }) | | | ANS =< iff, Al ] | \ A » Li | IN Fig. 169. Interior of dorsal valve. Fig. 170. Specimen with fringe. hinge-line curved, area obsolete, foramen round, truncating the beak, deltidium obsolete ; hinge-plate of dorsal valve with four muscular cavities, perforated by a small round foramen, and supporting a small complicated loop (?) between the spires; spires directed outwards, crura united by a prominent oral loop. The foramen in the hinge-plate occupies the situation of the notch through which the intestine passes in the recent Rhyn- chonelle ; in A. concentrica a slender curved tube is sometimes attached to the foramen, beneath the hinge-plate. A. tumida has the hinge-plate merely grooved, and the byssal foramen is angular. ‘ Fossil, about 70 species. Silurian—Lias. North and South America and Europe. * Sometimes employed, incorrectly, in the sense of a door-way or for men, + The spurious genus Actinoconchus (M‘Coy) was founded on this character ; similat expansions are formed by species of Atrypa, Camarophoria, and Producta, 874 MANUAL OF THE MOLLUSCA. . : Sub-genus? Merista, Suess. ‘Ter. scalprum, Roemer. (A. cassidea, Quenst. Sp. plebeia, Ph.) Silurian —Deyonian. Europe. Shell impunctate, dental plates (v) and dorsal septum (d) sup- ported by arched plates (‘‘ shoe-lifter ” processes, of King) which readily detach, leaving cavities (as in Fig. 171); spiral arms Fig, lil. Merista. aye been observed in all the species. RErz1A, King. Dedicated to the distinguished Swedish naturalist, Retzius. Type, Ter. Adrieni, Vern. Example, R. serpentina, Carb. L., Belgium, Fig. 172. Shell punctate, terebratula-shaped; beak truncated by a round foramen, rendered complete by a distinct deltidium ; hinge-area small, triangular, sharply defined; interior with diverging shelly spires. Fossil, about 50 species. Silurian United States, Europe. Professor King first pointed out the existence of calcareous + spires in several J'erebratule of the older rocks, and others have been discovered by MM. Quenstedt, De Koninck, and Barrande. In form they resemble Terebratulina, Hudesia, and Lyra. Trias. South America, Fig. 172. Retzva serpentina, D. K. Fig. 173. Uncites gry) hus. UnciTEs, Defrance. Type, U. gryphus, Pl. XV., Fig. 17. Fig. 173. Fossil, Deyonian. Europe. Shell impunctate; oval, bi-convex, with a long incuryed— beak ; foramen apical, closed at an early age; deltidium large, concaye; spiral processes directed outwards; no hinge-area, The large, concave deltidium of Uncites so much resembles | the channel formed by the dentai plates of Pentamerus, that — BRACHIOPOD Ae 0190 Dalman mistook the shell fora member of that genus. The discovery of internal spires, by Professor Beyrich, shows that it only differs from efzia in being impunctate and destitute of hinge-area. Some of the specimens haye corresponding depres- sions in the sides of the valves (Fig. 173, p), forming pouches which do not communicate with the interior. ‘ FaAmity I1].—RiYNCHONELLIDZ. Shell impunctate, oblong, or trigonal, beaked; hinge-line curyed; no area; yalyes articulated, convex, often sharply plaited; foramen beneath the beak, usually completed by a Fig. 174. BR. nigricans. Ventral, Fig. 175. Dorsal. Fig. 174. Dorsal valve with the animal; a, adductor muscles ; 7, intestine.” Fig. 175. R. psittacea, interiors. s, septum ; f, foramen; d, deltidium; ¢, teeth; ¢’, sockets; ¢, oral lamelle ; a, adductor impressions ; r, cardinal; p, pedicle muscles; 0, ovarian spaces, deltidium, sometimes concealed; hinge-teeth supported by dental plates; hinge-plate deeply divided, supporting oral lamellz, rarely provided with spiral processes; muscular im- pressions grouped as in Terebratula; vascular impressions consisting of two principal trunks in each yalye, narrow, dichotomising, angular, the principal posterior branches inclos- ing ovarian spaces. Animal (of Rhynchonella) with elongated spiral arms, directed inwards, towards the concavity of the dorsal valve; alimentary canal terminating behind the insertion of the adductor in the ventral valve; mantle not adhering, its margin fringed with a _ few short setz. RHYNCHONELLA, Fischer. Synonyms, Hypothyris, Phil. Hemithyris (psittacea), D’Orbigny. Acanthothyris (spinosa), D’Orbigny. Cyclothyri: sein M‘Coy. Trigonella (part), Fischer (not L. nor Da osta). 876 MANUAL OF THE MOLLUSCA. Types, R. acuta, Pl. XY., Fig. 18; furcillata, Fig. 195m spinosa, Fig. 20; acuminata, Fig. 176; nigricans, Fig. 174; psittacea, Fig. 175 (p. 5, Fig. 4). b $ r - & ; t Ventral aspect. Umbonal aspect. _ Fig. 176, 2h. acuminata, internal casts. Fig. 176. Umbonal aspect, with the dorsal valve above (Coll. Professor King). Ventral aspect (Coll, Professor Morris). A, adductor; R, cardinal; P, pedicle; V, — vascular ; O, ovarian impressions. ; Shell trigonal, acutely beaked, usually plaited ; dorsal valve elevated in front, depressed at the sides; ventral valve flattened, or hollowed along the centre, hinge-platessupporting two slender — curved lamellee ; dental plates diverging. % The foramen is at first only an angular notch in the hinge- — line of the ventral valve, but the growth of the deltidium usually _ renders it complete in the adult shell; in the cretaceous species — it is tubular. In R. acuminata and many other palozoie - ‘examples, the beak is so closely incurved as to allow no space © for a pedicle. Both the recent Rhynchonelle are black; 2. octo- — plicata of the Chalk sometimes retains six dark spots. a Distribution, 4 species. L. psittacea, Labrador (low water ?), Jfudson’s Bay (100 fathoms), Molville Island, Sitka, Icy Sea. It. nigricans, New Zealand, 19 fathoms. a Fossil, 332 species. ‘Lower Silurian—. North and South America, Europe, Thibet, China. Sub-genera. ? Porambonites, Pander. P. sequirostris, Schl. Shell impunctate; surface minutely pitted; each yalye witha minute hinge-area and indications of two septa; foramen angular, usually concealed. Distribution, 8 species. or Silurian. Russia and Portugal. 4 Camarophoria, King. 'T. crumena, Martin (sp.). Figs. 177, 178. Ventral yalye with conyerging dental plates (d) supported BRACHIOPODA: Sei on a low septal ridge (s); dorsal valve with a prominent septum (s) supporting a spoon-shaped central process (v); oral lamelles long and slender (0), foramen angular, cardinal process dis- tinct (j). J’ossil,9 species. Carp.—Permian (Magnesian lime- stone.) Germany and England. Fig. 177. Internal cast.* Fig. 178. Section. PENTAMERUS, Sowerby. Etymology, pentameres, 5-partite. Synonym, Gypidia (conchydium), Dalman. Pyne > Knight, Pl. XV., Fig. 22. Fig. 179. Shell impunctate, ovate, ventricose, with a large incuryed beak; valves usually plaited; foramen angular; nO area or deltidium ; dental plates (d) converging, trough-like, supported on a prominent septum (s); dorsal yalye with two contiguous ee, Longitudinal. Fig. 179. Transverse section. longitudinal septa (ss) opposed to the plates of the other valve. Oral lamellz haye been detected by Mr. Salter in P. liratus ; # Ventral side of cast, showing the V-shaped cavity of the dental plates, and the Impressicns of branchial yeins, accompanied by arteries (after King), 378 MANUAL OF THE MOLLUSCA. in P. ? brevirostris (Devonian, Newton) the dorsal valve has a long trough-like process supported by a single low septum. Fossil, 52 species. Upper Silurian—Deyonian. Arctic America, United States, Europe. The relations of the animal to the shell in such a species as P. Knightii can only be inferred by comparison with other species in which the internal plates are less developed, and with other genera, such as Cyrtia and Camarophoria. In Fig. 179, the small central chamber (v) must have been occupied by the digestive organs, the large lateral spaces (ds) by the spiral arms; it is doubtful whether any muscles were attached to these plates; in Porambonites the adductor impression is situated beyond the point to which the dental plates converge, and in Camarophoria the muscular impressions occupy the same position as in Ihynchonella. ATRYPA, Dalman. Synonyms, Cleiothyris, Phillips. Spirigerina, D’Orbigny.* Hipparionyx, Vanuxem. Type, A. reticularis, Pl. XV., Fig. 21. Figs. 180, 181. 5° = SS —Y,S ely S % .§ ‘ YEO Se sesh ~¥ ay \ PN Fiz. 180, Dorsal valve. Fig. 181, Ventral valve ; interiors. p, hinge-plate; a, impressions of adductor muscle; c, cardinal muscle; p, pedicle muscle; 0, ovarian sinus; d, deltidium. Shell impunctate ; oval, usually plaited and ornamented with squamose lines of growth; dorsal valve gibbose; ventral depressed in front; beak small, often closely incuryed ; foramen round, sometimes completed by a deltidium, often concealed ; dorsal yalve with a divided hinge-plate, supporting two broad spirally coiled lamellie ; spires vertical, closely appressed, and * The term Atrypa, (a, without, trupa, foramen) is objectionable, like all Dalman’s names; but M. D’Orbigny has made no improvement by proposing ‘pigs in add‘tion to Spirifera, Spirigera, and Spiriferina BRACHIOPODA. 379 directed towards the centre of the valve; teeth and impressions like Rhynchonella. The shells of this genus differ from Rhynchonella chiefly in the calcification of the oral supports, a character of uncertain value. Fossil, 21 species. Tower Silurian—Trias. America (Wel- lington Channel! Falkland Islands), Europe, Thibet. Anoplotheca lamellosa, F. Sandberger, 1856, Devonian, Rhine, is a species of Atrypa. Famity [VY.—OrtTHIDz.* Shelé transversely oblong, depressed, rarely foraminated ; hinge-line wide and straight; beaks inconspicuous; valves plano-conyex, or concayo-conyex, each with a hinge-area (h) notched in the centre; ventral yalye with prominent teeth (¢) ; “muscular impressions occupying a saucer-shaped cavity with a “raised margin; adductor (a) central; cardinal and pedicle impressions (7) conjoined, lateral, fan-like; dorsal valve with a oth-like cardinal process between two curyed brachial pro- cesses (c); adductor impression (a) quadruple ; vascular impres- sions consisting of six principal trunks in the dorsal valve, two the ventral, the external branches turned outwards and back- ards inclosing wide ovarian spaces (0). Indications have been a Fe 6 hdr aa és ty haan " man - “om, Dorsal valve.f Ventral valve. Fig. 182. Orthis striatula, Devonian, Eifel. __ * The names of the families are formed from those of the typical genera, by sub stituting ide for the last syllable of the genitive case. + From a specimen presented by M. De Koninck to the British Museum; internal] casts of this fossil were called hys‘erolites by old authors. i 380 MANUAL OF THE MOLLUSCA. OrtTHIS, Dalman. Etymology, orthos, straight. Type, O. rustica, Pl. XV., Fig. 23. . Synonyms, Diccelosia (biloba), King. Platystrophia (biforata), King. Gonambonites (inflexa), Pander. Orthambonites (calli- gramma), Pander. Shell transyersely oblong, radiately striated or plaited, bi- conyex, hinge-line narrower than the shell, cardinal process simple, brachial processes tooth-like, prominent and curved. Fossil, 154 species. Lower Silurian—Carb. Arctic America, United States, South America, Falkland Islands, Europe, Thibet. ? Sub-genera. Orthisina, D’Orbigny. O. anomala, Schl. Fig. 183. Synonyms, Pronites (ascendens) and Hemipronites, Pander. Shell impunctate ? widest at . the hinge-line; cardinal notch closed, byssal notch (/fissure) covered by a convex pseudo-deltidium, sometimes perforated by a small round foramen. Fossil, Lower Silurian, Europe. O. pelargonatus (Streptorhynchus, © King), from the Magnesian limestone, O. senilis, Carb. limestone, and some Devonian species, haye the beak twisted, as if it had been attached ; there is no foramen. Fig. 183. Orthisina. STROPHOMENA, Blainyille.* Etymology, strophos, bent, mene, crescent, ; Examples, 8. rhomboidalis, Pl. XV., Fig. 24. (=Productus depressus, Sby.) . Synonyms, Lepteena (rugosa), Dalman. . Leptagonia, M‘Coy. — Enteletes, Fischer. Shell semicircular, widest at the hinge-line, concayo-convex, - depressed, radiately striated ; area double; ventral valve with | an angular notch, progressively covered by a conyex pseudo- deltidium ; umbo depressed, rarely (?) perforated, in young shells, by a minute foramen (Fig. 184, e); muscular depressions © 4, central pair narrow, formed by the adductor; external pair (m) fan--like, left by the cardinal and pedicle nrustles ; dorsal * The name Strophomena (rugosa) was originally given by Rafinesque to some un- known or imaginary fossil; it has, however, been adopted both in America ane 4 Europe for the group typified by S. alternata and planumbona, BRACHIOPODA. 381 valve with a bi-lobed cardinal process, between the dental sockets, and four depressions for the adductor muscles. Ventral valve. Fig. 184. Dorsal valve. Interior of S. rhomboidalis, var. analoga, Carb. limestone (after King). e,foramen ; ¢, teeth; 0, ovarian spaces; 0, brachial pits ? There are no apparent brachial processes in the dorsal valve of Strophomena, and it is possible that the spiral arms may have been supported at some point near the centre of the shell (d) as -in Productus; S. rhomboidalis occasionally exhibits traces of spiral arms, in the ventral valve. 8. latissima, Bouch., has plain 2 ee -areas, ike Calceola. B _ The valves of the Strophomenas are nearly flat until they approach their full growth, they then bend abruptly to one side; the dorsal valve becomes concave in S. alter- nata and rhomboidalis, whilst in S. planumbona and euglypha it puis Paes b ee ey; these distine- A, hinge-areas; v, ventral ; interior tions are not even sub-generic. of dorsal valve. Fossil, 129 species. Lower Silurian—Carb. North America, Europe, Thibet. S. denvissa, Conr. (Stropheodonta, Hall), S. Dutertrii, and several other species have a denticulated hinge-line. Sub-genera ? Leptena (part), Dalman. I. transversalis, Fig. 185. (Plectambonites, Pander.) Valves regularly curved; dorsal concave, thickened, muscular impressions elongated. Fossil, 41 species. Lower Silurian—Lias. North America and Europe. The lias Leptenas resemble T'hecidia internally ; they are free shells, with sometimes a minute foramen at the apex of - rhe triangular deltidium ; Z. liassina, Pl. XV., Fig. 25. _ Koninckia, Suess. Producta Leonhardi, Wissm. (P. alpina. Schl.), Fig. 186. Trias, St. Cassian. Shelt orbicular, concayo- conyex, smooth; valves articulated ? closely appressed ; ventral valye conyex, dorsal concaye; beak incuryed, no hinge-area Ml ‘ Ni (LIN iil : MUTT > TT bs ak 382 MANUAL OF THE MOLLUSCA, nor foramen? interior of each valve furrowed by two spiral lines — of four yolutions, directed inwards, and crossing the vascular . ° ° : ° : . impressions; umbo with three diverging ridges. The small Fig. 186. Froductus? Leonhardi, 2..* spiral cavities, once occupied by the arms, and now filled with Spar, may be seen in specimens with both valves, by holding them tothe light. M. Suess, of Vienna, states that he has found traces of very slender spiral lamelle occupying the furrows. This curious little shell most resembles the Triassic Leptena dubia (Productus), Minster (= Crania Murchisoni, Klipst ye DaAvinsoniA, Bouchard. Dedicated to the author of the Monograph of British Fossil — Brachiopoda. : Type, D. Verneuili, Bouchard. Fig. 187. Devonian, Eifel. r Z WS Yip =OU« ling An TANTIAUWS Dorsal valve, Fig. 187. - Ventral valve.2 Sheil solid, attached by outer surface of the ventral yalvye to rocks, shells, and corals; valves plain, articulated; ventral valve with a wide area (h); foramen angular, covered by a convex deltidium (d); disk occupied by two conical elevations, obscurely grooved by a spiral furrow of 5-6 yvolutions; dorsal valve with two shallow lateral cavities; vascular impressions consisting of two principal sub-marginal trunks, in each yalve, 8 A, translucent specimen; B, interior of dorsal valve. g BRACHIOPODA, 388 é with diverging branches; cardinal and adductor impressions distinct. The furrowed cones undoubtedly indicate the existence of spiral arms, similar to those of Atrypa (Fig. 180), but desti- tute of calcified supports. The upper valve sometimes exhibits markings derived from the surface on which the shell has grown. The mantle- lobes seem to haye continued depois shell until the internal cayity was reduced to the smallest possible limit. Fossil, 3 species. Devonian—Trias. Dorsal valve Fig. 188. Ventral valve, CALCEOLA, Lamarck. Etymology, calceola, a slipper. Type, C. sandalina, Pl. XY., Fig.26. Fig. 188. Shell thick, triangular ; valves plain, not articulated ; ventral valve pyramidal; area large, flat, triangular, with an “obscure central line; hinge-line seen, crentlated, dorsal valve flat, semicircular, with a narrow area (h), a small cardinal process (7), and two lateral groups of small apophysary (?) ridges (0); internal surface punctate-striate. Fossil, Devonian, Eifel, Britain. The supposed Carboniferous species (Hypodema, D.K.) is, per- haps, related to Pileopsis. Calceola is shaped lke Cyrtia, and its hinge-area resembles that of some Strophomenas. FAMILY V.—PRODUCTIDE, Shell concayo-conyex, with a straight hinge-line; yalves rarely articulated by teeth; closely appressed, furnished with tubular spines; ventral valve convex ; dorsal concaye; internal surface dotted with conspicuous, funnel-shaped punctures; dorsal valve with a prominent cardinal process; brachial pro- cesses (7) sub-central ; vascular markings lateral, broad, and simple ; adductor impressions dendritic, separated by a narrow eentral ridge ; ventral yalye with a slightly notched hinge-line; oot MANUAL OF THE MOLLUSCA. adductor scar central, near the umbo; cardinal impressions lateral, striated. . ; Fig. 189. Productus giganteus, } Carb. limestone. A, interior of dorsal valve; B, interior of ventral valve, with the umbo removed; C, ideal section of both valves; D, hinge-line of A; 7, cardinal process; a, adductor$ 7, cardinal muscles; 6, oral processes?; s, hollows occupied by the spiral arms; v, vascular impressions ; A, hinge-area. PRODUCTUS, Sowerby. Types, P. giganteus, Martin. =Anomia producta, Martin. Examples, P. horridus, Pl. XV., Fig. 27. P. proboscideus, ~ Pl. XYV., Fig. 28. Shell free, auriculate, beak large and rounded; spines scat- tered; hinge-area in each valve linear, indistinct; no hinge- teeth ; cardinal process lobed, striated; vascular impressions © snple, curved; ventral valve deep, with two rounded or sub- — spiral cavities in front. These shells may have been attached by a pedicle when young, the impressions of the pedicle-muscle 4 blending with those of the hinge-muscles (c) in the ventral — valve. “A few species appear to haye been permanently fixed. — P. striatus is irregular in its growth, elongated and tapering towards the beak, and occurs in numbers packed closely together. P proboscideus seems to haye lived habitually in cavities, or half-buried in mud, as suggested by M. D’Orbigny; its ventral valve is prolonged several inches beyond the other, and has its ——_--~S-~S _ with long slender spines; valves arti- _ fissure covered; vascular impressions On BRACHIOPODA, o& edges rolled together and united, forming a large permanently open tube for the brachial currents. The large spines are most usually situated on the ears of the ventral valve, and may hayo served to moor the shell; being tubular they were permanently susceptible of growth and repair. Although edentulous, the dorsal valve must have turned on its long hinge-line with as much precision asin those genera which are regularly articulated by teeth. Fossil, 81 species. Devonian—Permian. North and South America, Europe, Spitzbergen, Thibet, Australia. WORE BAaN 8 Ko Exterior. Pig. 190, Tnterior, Sub-genus. Aulosteyes, Helmersen. A. Wangenheimii, Vern., Fig. 190. Permian, Russsia; Carb. Shell like Producta; ventral valve with a large flat triangular hinge-area (h), with a narrow conyex pseudo-deltidium (d) in the centre; beak alittle distorted, as if attached when young; dorsal valve slightly convex near the umbo ; interior as in Productus (lungi-spinus). STROPHALOSIA, King. Example, S. Cancrini, De Vern., Fig. bo1; Synonym, Orthothrix, Geinitz. Shell attached by the umbo of the ventral valve; sub-quadrate; covered culated, dorsal moderately concave, ventral convex, each with a small area; coujuined, reniform. Fossil, 8 species. Devonian—Carb. “uropo, Himalaya (Gevard). Fig, 19) S. Cuncrin. 286 MANUAL OF THE MOLLUSCA, CHONETES, Fischer. Example, C. striatella, Pl. XV., Fig. 29. Etymology, chone, a cup. Shell transversely oblong, with a wide and er hinge-line; area double; valves radiately striated, ar ficaieted hinge-margir of ventral valve with a series of tubular spines; fissure covered; interior punctate-striate; vascular impressions (v) very small. (Davidson. ) Fossil, 47 species. Silurian—Carboniferous.. Europe, North America, Falkland Islands. . Dorsal valve, Fig. 192. Ventral valve.* ‘ FAMILY VI.—CRANIADZA. Shell orbicular, calcareous, hinge-less ; attached by the umbo, or whole breadth of the ventral valve, rarely free; dorsal valve limpet-like ; interior of each valve with a broad granulated border ; disk with four large muscular impressions, and digitated vascular impressions ; structure punctate. Animal with free spiral arms, directed towards the concayity of the dorsal valve, and supported by a nose-like prominence in. the middle of the lower valve; mantle extending to the edges of the valves, and closely adhering; its margins plain. (Fig. 195.) CRANIA, Retzius. Etymology, kraneia, capitate. Type, Anomia craniolaris, L. . Examples, C. Ignabergensis, Pl. XV., Fig. 30. C. anomala, Figs. 193—195. Synonyms, Criopus, Poli. Orbicula (anomala), Cuvier, =O. Norvegica, Lam. . * Interiors of two sp. of Chonetes, from Nehou and the Eifel, after Davidsen: @ adductor ; c, cardinals. ; BRACHIOPODA. | 387 Shell smooth or radiately striated ; umbo of dorsal valve sub- central ; of ventral yalye sub-central, marginal, or prominent and cap-lke, with an obscure triangular area traversed by a central line. The large muscular impressions of the attached valve are Fig. 193. Ventral valve. Fig. 194. Dorsal valve. Crania anomala, Muller. ¢ Zetland. a, anterior adductors; a’, posterior adductors; c, posterior adjustors; c', cardinal muscle ; 7, 0, central and external adjustors. : sometimes convex, in other species deeply excavated; those of the upper valve are usually convex, but in C. Parisiensis the anterior (central) pair are developed as prominent diverging apophyses. In C. tripartita, Miimster, the nasal process divides the fixed valve into three cells.* C. Ignabergensis 1s equivalve, and either quite free or very shghtly attached. C. anomaila is gregarious on rocks and stones in deep water, both in the North Sea and Mediterranean (40—90 fathoms, living ; 150 fathoms, dead; Forbes); the animal is orange-coloured, and its labial arms are thick, fringed with cirri, and disposed in a few horizontal gyrations (Fig. 195). Distribution, 5 species. Spitzbergen, Britain, Mediterranean, India, New South Wales. —150 fathoms. Fossil, 37 species. Lower Silurian—. Europe C. antiquissima, Eichw. (Pseudo-crania, M‘Coy), is free, and has the internal border of the valves smooth; the branchial impressions blend in front. Spondylobolus craniolaris, M‘Coy, is a small and obscure fossil, from the Lower Silurian shale of Builth. The upper valve appears to have been like Crania, the lower to have had a small grooved beak, with blunt, tooth-like processes at the hinge-line. * M. Quenstedt has placed the Oolitic Cranias in Siphonaria ! $2 388 MANUAL OF THE MOLLUSCA, : FAMILY VII.—DIScCINIDA. Shell attached by a pedicle, passing through a foramen in the ventral valye; valves not articulated ; minutely punctate. Fig. 195. Crania.* Fig. 196. Discina.t Animal with a highly vascular mantle, fringed with long horny sete; oral arms curved backwards, returning upon them- selves, and ending in small spires directed downwards, towards the ventral valve. Discrna, Lamarck. Synonyms, Orbicula, Sby. (not Cuvierf). Orbiculoidea (elliptica), D’Orbigny. Schizotreta, Kutorga. Types, D. lamellosa, Pl. XY., Fig. 31. (=D. ostresides, Lamarck.) Shell orbicular, horny ; upper valve limpet-like, smooth or concentrically lamellose, apex behind the centre; lower valve flat or conical, with a sunk and perforated disk on the posterior side; interior polished; lower valve with a central prominence in front of the foramen. Animal transparent; mantle lobes distinct all round; labial folds united, not extensile, ; alimentary canal simple, bent upon itself ventrally, and terminating between the mantle-lobes on — the right side. There are four distinct adductor muscles as in | * Dorsal valve, with the animal, seen by removing the mantle. + The animal as seen on the removal of part of the lower mantle-lobe ; the extremitie of the labial arms are displaced forwards, in order to show their spiral terminations ! » is the expanded surface of the pedicle; the mouth is concealed by the overhangi cirri. The mantle-fringe is not represented. : + The Orbicula of Cuvier was the Patella anomala, Miili (= Crania), as pointed o _by Dr. Fleming, in the “ History of British Animals,” 1828. BRACHIOPODA. 389 Crania; and three pair of adjustor muscles for keeping the valves opposed to each other. Some of these are probably inserted in the pedicle. The oral cirri are extremely tender and flexible, contrasting with th: stiff and brittle setze of the mantle, é AN AWN yy y yyy A ANNALS “a Ui fii Ma TERA AT : ! Hi i | A F.g. 197. Dorsal. Fig. 198. Ventral lobe. Discina lamellosa, Brod. 2 u,umbo; f, foramen; d, disk; a, anterior adductors; a’, posterior adductors ; c, c', central and posterior adjustors ; r, external adjustors. The mantle-fringe is not represented in Fig. 198, Ww, i which are themselves setose like the bristles of certain annelides (e.g. the sea-mouse, Aphrodite). The relation of the animal to the perforate and imperforate valves is shown to be the same as in Terebratula, by the labial fringe; but the only process which can possibly have afforded support to the oral arms is developed from the centre of the ventral valve, as in Crania. Baron Ryckholt has represented a Devonian fossil from Belgium, with a fringed border; but if this shell is the Crania obsoleta of Goldfuss, the fringe must belong to the shell, and not to the mantle. Distribution, 10 species. West Africa, Malacca, Peru, and Panama. Fossil, 64 species. Silurian—. Europe, United States, Falkland Islands. In some species the yalyes are equally convex, and the __ foramen occupies the end of a narrow groove. Sub-genus. Trematis, Sharpe. (=Orbicella, D’Orbigny.) T. terminalis, Emmons. Valves conyex, superficially punctate; dorsal valve with a thickened hinge-margin (and three diverg- ing plates, indicated on casts.x—Sharpe). Jossil, 14 species. Lower and Upper Silurian. North America and Europe. 890 MANUAL OF THE MOLLUSCA, SIPHONOTRETA, Verneuil. Etymology, siphon, a tube, tretos, perforated. Types, 8. unguiculata, Hichw., Figs. 199, 201. SS. verrucosa, Fig. 200. Shell oval, bi-conyex, slightly beaked, conspicuously punctate, or spiny; beak perforated by a tubular foramen ; hinge-margins Fig. 199. Fig. 200. Exterior. Fig. 201. Interior, thickened; ventral valye with four close adductor scars sur- rounding the foramen. ‘The spines are tubular, and open into the interior of the shell by prominent orifices. (Carpenter.) S. anglica, Morris, has moniliform spines. Fossil, 9 species. Lower and Upper Silurian. Britain, Bohemia, Russia. 5 ? Acrotreta (sub-conica), Kutorga. 3 species. Lower Silurian, Russia. Shaped like Cyrtia, with an apical foramen; no hinge. Famity VIIT.—LINGcULIDz. Shell oblong or orbicular, sub-equivalve, attached by a pedicle passing out between the yalyes; texture horny, minutely tubular. - Animal «with a highly vascular mantle, fringed with horny setze; oralarms thick, fleshy, spiral, the spires directed inwards, _ towards each other. 2 LINnGULA, Bruguiére. Etymology, lingula, a little tongue. Type, li. anatina, Pl. XY., Fig. 32. Shell oblong, compressed, slightly gaping at each end, trun-— cated in front, rather pointed at the umbones; dorsal valve rather shorter. with a thickened hinge-margin, and a raised central ridge inside. BRACHIOPODA. 391 Animal with the mantle-lobes firmly adhering to the shell, and united to the epidermis, their margins distinct, and fringed all round ; branchial veins giving off numerous free, elongated, narrow loops from their inner surfaces; visceral cavity occupy- Wp Estes Fig. 202. Dorsal.* Fig. 203. Ventral. Fig. 204. Ventral. Lingula anatina, Lam. (original). Syn. Patella unguis, L. (part.) aa, anterior adductors ; a', posterior adductor; p p, external adjustors ; p'p’, central adjustors; 7 7, anterior retractors (the anterior occlusors of Hancock); r'7'r', posterior adjustors; c, capsule of pedicle; mm, visceral sheath; 0, cesophagus; s, stomach, i, liver ; z,intestine; v, vent; 0, branchial vessels ; ™', mantle margin; m, inner lamina of mantle margin retracted, showing bases of sete; s, sete. ing the posterior half of the shell, and surrounded by a strong muscular sheath ; pedicle elongated, thick; stomach long and straight, sustained by inflections of the visceral sheath; intes- tine conyoluted dorsally, terminating between the mantle-lobes on the right side, oral arms disposed in about six close whorls, their cayities opening into the prolongation of the visceral sheath in front of the adductors. Observations on the living lingula are much wanted; the oral arms probably extended as far as the margins of the shell; and the pedicle, which is often nine inches long in preserved specimens, is doubtless much longer, and contractile when * In Fig. 202 a small portion of the liver and visceral sheath have been removed, to slow the course of the stomach and intestine. In some specimens the whole of the viscera, except a portion of the liver, are concealed by the ovaries. In Fig. 204 the front half of the ventral mantle-lobe is raised, to show the spiral arms; the black spot ‘in the centre is the mouth, with its upper and lower lips, one fringed, the other plain. The mantle-fringe has been omitted in Figs. 202, 204. 392 MANUAL OF THE MOLLUSCA. 7 alive. The shell is horny and flexible, and always of a greenish colour. Distribution, 16 species. India, Philippines, Moluccas, Aus- tralia, Feejees, Sandwich Islands, West America. Fossil, 91 species. Lower Silurian—. North America, Europe, Thibet. Lingule existed in the British seas as late as the period of the Coralline Crag. The recent species have been found at small depths, and even at low water half buried in sand. ZL Davisit, Lower Silurian, Tremadoc, has a pedicle-groove like Obolus, Fig. 205. (Salter.) Fig. 205. Ventral valve. Fig. 206. Dorsal valve. Obolus Davidsont. (Salter.) Wenlock limestone, Dudley. A, posterior adductors; B, adjustors; C, anterior adductors. The pedicle-scar in the centre of Fig. 168 has no letter. Oxsouus, Eichwald. Synonyms, Ungula, Pander; Aulonotreta, Kutorga. Etymology, obolus, a small Greek coin. Type, O. Apollinis, Eichw. Shell orbicular, caleareo-corneous, depressed, sub-equivalve, smooth; hinge-margin thickened inside, and slightly grooved in the ventral valve; posterior adductor impressions separate ; anterior pair sub-central; impressions of adjustors lateral. Fig. 205, 206. (After Davidson.) Fossil, 8 species. Lower and Upper Silurian. Sweden, — Russia, England, United States. CONCHIFERS:? 0938 CHAPTER IY. CLASS V. CONCHIFERA, Lamarcr. (Lamelli-branchiata, Blainyille.) The bivalve shell-fish, or Conchifera, are familiar to every one, under the form of oysters, scallops, mussels, and cockles.* They come next to the univalves (gasteropoda) in variety and importance, and though less numerous specifically, are far more abundant indiyidually.t ‘The bivalves are all aquatic, and excepting a few widely-dispersed and prolific genera, are all inhabitants of the sea; they are found on every coast, and in every climate, ranging from low-water mark to a depth of more than 200 fathoms. In their natiye element the Oyster and Scallop lie on one side, and the lower valve is deeper and more capacious than the upper; in these the foot is wanting, or else small, and not used for locomotion. Most other bivalves live in an erect position, resting on the edges of their shells, which are of equal size. Those which moye about much, like the river-mussel, maintain themselves nearly horizontally,{ and their keel-shaped foot is adapted for ploughing through sand or mud. The position of those bivalves which live half-buried in river-beds or at the bottom of the sea, is often indicated by the darker colour of the part exposed; or by deposits of tufa, or the growth of seaweed on the projecting ends of the valves. In Nucula and some others the foot is deeply cleft, and capable of expanding into a disk, ike that on which the snails glide; whilst in the mussel, pearl-oyster, and others which habitually spin a byssus, the foot is finger-like and grooved. The burrowing species have a strong and stout foot with which they bore vertically into the sea-bed, often to a depth far exceeding the length of their valves; these never volun- tarily quit their abodes, and often become buried and fossilised inthem. They most usually burrow in soft ground, but also incoarse gravel, and firm sands and clays; one small modiola makes its hole in the cellulose tunic of Ascidians, and another in floating blubber. * They are the Dithyra of Aristotle and Swainson, and constitute the second or sub-typical group in the quinary system. j It has been stated that the predatory mollusca are more numerous than the vegetable-feeders ; but it is not so with the individuals constituting the species. } This is the position in which they are always figured in English books, being best suited for the comparison of one shell with another. $3 394 MANUAL OF THE MOLLUSCA. The boring shell-fish have been distinguished from the mere burrowers, perhaps without sufficient reason, for they are found in substances of every degree of hardness, from soft mud to compact limestone, and the method employed is probably the same.* The means by which bivalves perforate stone and timber has been the subject of much inquiry, both on account of its phy- siological interest, and the desire to obtain some remedy for the injuries done to ships, and piers, and breakwaters. The ship-worm (feredo) and some allied genera, perforate timber only ; whilst the pholas bores into a variety of materials, such as chalk, shale, clay, soft sandstone and sandy marl, and decomposing gneiss ;+ it has also been found boring in the peat of submarine forests, in wax, and in amber.{ It is obvious that these substances can only be perforated alike by mechanical means; either by the foot or by the valves, or both together, as in the burrowing shellfish. The pholas shell is rough, lke a file, and sufficiently hard to abrade limestone; and the animal is able to turn from side to side, or even quite ~ound in its cell, the interior of which is often annulated with furrows made by the spines on the front of the valves. The foot of the pholas is very large, filling the great anterior opening of the valves; that of the ship-worm is smailer, but surrounded with a thick collar, formed by the edges of the mantle, and both are armed with a strong epithelium. The foot appears to be a more ; a efficient instrument than thé shell in one respect, inasmuch as its surface may be renewed as fast as it is worn away.§ (Han- cock. = mechanical explanation becomes more difficult in the case of another set of shells, lithodomus, gastrochena, saxicava, and wngulina, which bore only into calcareous rocks, and attack the hardest marble, and still harder shells. (Fig. 25, p. 34). In these the valves can render no assistance, as they are smooth, and covered with epidermis; neither does the foot help, being small and finger-like, and not applied to the end of the burrow. Their power of movement also is extremely limited, their cells not being cylindrical, whilst one of them, sawicava, is fixed in * See the admirable memoir by Mr. Albany Hancock, in the An. Nat. Hist. for October, 1848. + There is a specimen from the coast of France, in the Brit. Museum, } Highgate resin, in the cabinet of Mr. Bowerbank. § The final polish to some steel goods is said to be given by the hands of work- ; women, In Carlisle Castle they point to the rude impression of a hand on the — dungeon wall, as the work of Fergus M‘Ivor, in the two years of his solitary im- prisonment, CONCHIFERA. mets? 5 its crypt by a dyssus. These shell fish have been supposed to dissolve the ruck by chemical means (Deshayes), or else to wear it away with the thickened anterior margins of the mantle. (Hancock.)* The holes of the lithodomi often serve to shelter other animals after the death of the rightful owners; species of Modiola, Arca, Venerupis, and Coralliophaga, both recent and fossil, have been found in such situations, and mistaken for the real miners.+ The boring shell-fish have been called ‘‘ stone-eaters ” (lithophagi) and ‘‘ wood-eaters”’ (aylophagi), and some of them at least are obliged to swallow the material produced by their operations, although they may derive no sustenance from it. The ship-worm is often filled with pulpy, impalpable sawdust, of the colour of the timber in which it worked. (Hancock.) No shell-fish deepens or enlarges its burrow after attaining the full growth usual to its species (p. 35). The bivalves live by filtering water through their gills.t Whatever particles the current brings, whether organic or inorganic, animal or yegetable, are collected on the surface of the breathing-organ and conveyed to the mouth. In this manner they help to remove the impurities of turbid water.§ The mechanism by which this is effected may be most conye- * All attempts to detect the presence of an acid secretion have hitherto failed, as might be expected; for the hypothesis of an acid solvent supposes only a very feeble but continuous action, such as in nature always works out the greatest results in the end. See Liebig’s Organic Chemistry, and Dumas and Boussingault on the “‘ Balance of Organic Nature.” Intimately connected with this question are several other phenomena; the removal of portions of the interior of univalves, by the animal itself, as in the genera Conus, Auricula, and Nerita (Fig. 24, p. 32); the perforation of shells by the tongues of the carnivorous gasteropods, and the formation of holes in wood and limestone by limpets. Some facts in surgery also illustrate this subject, (1) dead bone is removed when granulations grow into contact with it: (2) if a hole is bored in a bone, and an ivory peg driven into it, and covered up, so much of the peg as is embedded in the bone will be removed. (Paget.) The “absorption” of the fangs of milk-teeth, previous to shedding, is weli known. In these cases the removal of the bone earth is effected without the development of an acid, or other disturbance of the neutral condition of the circulating fluid. + Fossil univalves (trochz) occupying the burrows of a pholas, were discovered by Mr. Bensted in the Kentish-rag of Maidstone. See Mantell’s Medals of Creation. M. Buvignier has found several species of Arca fossilised in the burrows of lithodomi. t It seems scarcely necessary to remark that the bivalves do not feed upon-prey caught between their valves. Microscopists are well aware that sediment taken from the alimentary canal of bivalve shellfish contains the skeletons of animalcules and Minute vegetable organisms, whose geometrical forms are remarkably varied and beautiful; they have also been obtained (in greater abundance than ordinary) from mud filling the interior of fossil oyster-shells. § When placed in water coloured with indigo, they will in a short time render it clear, by collecting the minute particles and condensing them into a solid form, 3096 MANUAL OF THE MOLLUSCA. niently examined in a bivalye with a closed mantle, like the great Mya (Fig. 207), which lives in the mud of tidal rivers, with only the ends of its long combined siphons exposed at the surface.* The siphons can be ex- tended twice the length of the shell, or drawn completely with- in it; they are separated, in- ternally, by a thick muscular wall. The branchial siphon (s) has its orifice surrounded by a double fringe; the exhalent siphon (s') has but a single row of tentacles; these organs are very sensitive, and if rudely touched the orifices close and the siphon itself is rapidly with- drawn. Whenunmolested, acur- rent flows steadily into the orifice of the branchial siphon, whilst another current rises up from the exhalent tube. There is no other opening in the mantle ex- cept a small slit in front (p) through which the foot is pro- truded. The body of the animal occupies the centre of the shell (b), and in frent of it is the mouth (0) furnished with an &/ upper and a lower lip, which are »*-/ prolonged on each side into a : pair of large membranous palpi (t). The gills (g) are-placed two on each side of the body, and are attached along their upper, or dorsal margins ; behind the body they are united to each other _ Fig. 207. Mya arenaria. f * Alder and Hancock on the branchial currents of Pholas and Mya. An. Nat. Hist., Nov. 1851. + Mya arenaria, tL. (original, from specimens obtained at Southend, and commu- nicated by Miss Hume). The left valve and mantle lobe and half the siphons are re- moved. a, a’, adductor muscles; 0, body; c, cloaca; 7, foot; g, branchize; A, heart; m, cut edge of the mantle ; 0, mouth; s, s', siphons; ¢, labial tentacles; v, vent. The arrows indicate the direction of the currents; the four rows of dots at the base of the gills are the orifices of the branchial tubes, opening into the dorsal channels, ~~ CONCHIFERA. 397 and to the siphonal partition. Each gill is composed of two lamin, divided internally into a series of parallel tubes, indicated outside by transverse lines; these tubes open into longitudinal channels at the base of the gills, which unite behind the posterior adductor muscle at the commencement of the exhalent siphon (c). Examined by the microscope, the gill laminz appear to be a network of blood-vessels whose pores opening into the gill-tubes, are fringed with vibratile cilia. These microscopic organs perform most important offices; they create the currents of water, arrest the floating particles, and mould them, mixed with the viscid secretion of the surface, into threads, in the furrows of the gill, and propel them along the grooved edge of its free margin, in the direction of the mouth; they are then received between the palpi in the form of rayelled threads. (Alder and Hancock.) In Mya, therefore (and in other burrowers), the cavity of the shell forms a closed branchial chamber, and the water which enters it by the respiratory siphon can only escape by passing through the gills into the dorsal channels, and so into the exhalent siphon. In the river-mussel the gills are not united to the body, but a slit is left by which water might pass into the dorsal channel, were it not for the close apposition of the parts under ordinary circumstances (Fig. 208 b). The gills of the oyster are united throughout, by their bases, to each other and to the mantle, completely separating the branchial cavity from the cloaca. In Pecten the gills and mantle are free, but the ‘‘dorsalchannels” still exist,and carry out the filtered water. In some genera the gills subserve a third purpose; the oviducts open into the dorsal channels and the eggs are received into the gill-tubes and retained there until they are hatched. In the river-mussel the outer gills only receive the eggs, _ with which they are completely distended in the winter months (Fig. 208, 0, 0). In Cyclas the inner gills form the marsupiwm, and only from 10 to 20 of the fry are found in them at one time ; these remain until they are nearly a quarter the length of the parent.* The valves of the Conchifera are bound together by an elastic ligament, and articulated by a hinge furnished with interlock- ing teeth. The shell is closed by powerful adductor muscles, but opens spontaneously by the action of the ligament, when the animal relaxes, and after it is dead. Each yalye isa hollow cone, with the apex turned more or * Some other particulars respecting the organisation and development of bivalve shell-fish are given in ChapterI. For an account of their vascular system see Milne- Edwards, An. Sc. Nat. 1847, tom, viii. p. 77. 398 MANUAL OF THE MOLLUSCA. less to one side; the apex is the point from which the growth of the valye commences, and is termed the beak, or wmbo (p. 29). The beaks (wmbones) are near the hinge, because that side erows least rapidly, sometimes they are quite marginal; but they always tend to become wider apart with age. The beaks are either straight, as in Pecten; curved, as in Venus ; or spiral, as in Isocardia and Diceras. In the latter case each valve is like a spiral univalve, especially those with a large aperture and small spire, such as Concholepas ; it is the left valve which ‘ resembles the ordinary univalve, the right valve being a left- handed spiral like the reversed gasteropods. When one valve is spiral and the other flat, as in Chama ammonia (Fig. 224), ea — SES Sa ERG Ups mm Hi } my Fig. 208. River-mussel. (Anodon cygneus Q) * the resemblance to an operculated spiral uniyalve becomes very striking. The relation of the shell to the animal may be readily deter- mined, in most instances, by the direction of the wmbones, and the position of the ligament. The umbones are turned towards the front, and the ligament is posterior ; both are situated on the back, or dorsal side of the shell. The length of a bivalye — is measured from the anterior to the posterior side, its breadth from the dorsal margin to the base, and its thickness from the centres of the closed valyes.+ The Conchifera are mostly equivalve, the right and left valves * The valves are forcibly opened and the foot (/) contracted; a, anterior adductor- muscle, much stretched; p, p, palpi; g, inner gills; 0, 0, outer gills distended with spawn ; 0, 6, a bristle passed through one of the dorsal channels. + Linneus and the naturalists of his school described the front of the shell as the back, the left valve as the right, and vice versa. In those works which have been compiled from “ original descriptions” (instead of specimens) sometimes one end, — sometimes the other, is called anterior; and the length of the shell is sometimes — estimated in the direction of the length of the animal, but just as frequently in a line at right angles to it. CONCHIFERA. 399 being of the same size and shape, except in the Ostreide and a few others. In Ostrea, Pandora, and Lyonsia, the right valve is smallest; in Chamostrea and Corbula, the left; whilst the Chamacee follow no rule in this respect. The biyalyes are all more or less inequilateral, the anterior Dorsal Margin, Posterior gS f ‘\ Anterior side. HK | “| side. : cae J Ventral margin or base. Fig. 209. Unio pictorum, L. (original), with the right valve and mantle-lobe removed ; a, a, adductor muscles; p, p, pedal muscles; z, accessory pedal muscle; u, umbo; 1, ligament ; 0, branchial orifice ; v, anal opening ; 7, foot; o, mouth; ¢, palpi. being usually much shorter than the posterior side. Pectunculus is nearly equilateral, and in G’ycimeris and Solemya the anterior is much longer than the posterior side. The front of the smaller Pectens is shown by the byssal notch ; but in the large scallops, oysters and Spondyli, the only indication of the posi- tion of the animal is afferded by the large internal muscular impression, which is on the posterior side. The ligament is sometimes between the umbones, but is never anterior to them. The siphonal impression, inside the shell, is always posterior. Biyalyes are said to be close, when the valves fit accurately, and gaping, when they cannot be completely shut. In Gastro- chena (Pl. X-XITI., Fig. 15), the opening is anterior, and serves for the passage of the foot; in Mya it is posterior and siphonal ; in Solen and Glycimeris both ends are open. In Bysso-arca (Pl. XVII., Fig. 13), there is a ventral opening formed by corresponding notches in the margin of the valves, which serves for the passage of the byssus; in Pecten, Avicula, and Anomia (Fig. 211, s), the byssal notch (or sinus) is confined to the right valve. The surface of bivalye shells is often ornamented with ribs which radiate from the umbones to the margin, or with con- centric ridges, which coincide with the lines of growth. Some- times the sculpturing is oblique, or wavy; in Tellina fabula at is confined to the right valye. In many species of Pholas aoe. J 400 MANUAL OF THE MOLLUSCA. Teredo, and Cardium, the surface is divided into two areas by © a transverse furrow, or by a change in the direction of the ribs. The lunule (see Fig. 14, p. 20) is an oval space in front of the beaks; it is deeply impressed in Cardiwm retusum, Li. Astarte excavata, and the genus Opis. Whena similar impression exists behind the beaks, it is termed the escutcheon.* The ligament of the Conchifera forms a substitute for the muscles by which the valves of the Brachiopoda are opened. It consists of two parts, the ligament properly so called, and the cartilage ; they exist either combined or distinct, and some- times one is developed and not the other. The external ligament is a horny substance, similar to the epidermis which clothes the valves; it is usually attached to ridges on the posterior hinge- margins, behind the umbones, and is consequently stretched by the closing of the valves. The ligament is large in the river- mussels, and small in the Mactras and Myas, which haye a large internal cartilage; in Arca and Pectunculus the ligament is spread over a flat, lozenge-shaped area, situated between the umbones, and furrowed with cartilage grooves. In Chama and Isocardia the ligament splits in front, and forms a spiral round each umbo. The Pholades have no ligament, but the anterior adductor is shifted to such a position on the hinge-margin that it acts as a hinge-muscle. (Pl. XXIII., Fig. 13.) The internal ligament, or cartilage, is lodged in furrows formed by the ligamental plates, or in pits along the hinge- line; in Mya and Nucwa it is contained in a spoon-shaped process of one or both valves. It is composed of elastic fibres placed perpendicularly to the surfaces between which it is contained, and is slightly iridescent when broken; it is com- — pressed by the closing of the valves, and tends forcibly to open them as soon as the pressure of the muscles is removed. The name Amphidesma (double ligament) was given to certain bivalves, on the supposition that the separation of the cartilage from the ligament was peculiar to them. ‘The cartilage-pit of © many of the Anatinide is furnished internally with a moyable © ossicle. . The ligament is frequently preserved in fossil shells, such. as the great Cyprinas and Carditas of the London Clay, th Unios of the Wealden and even in some lower Silurian biyalyes. All bivalves are clothed with an epidermis (v. p. 33) which is organically connected with the margin of the mantle. It is developed to a remarkable extent in Solemya and Glycimeris * Only those technical terms which are used in a peculiar sense are here referred to; for the rest, any Dictionary may be consulted, especially Roberts’s * Etymologicell Dictionary of Geology,” published by Longman and Co, CONCHIFERA. 401 (Pl. XXII., Figs. 13, 17), and in Mya it is continued over the siphons and closed mantle-lobes, making the shell appear internal, The interior of bivalves is inscribed with characters borrowed directly from the shell-fish, and affording a surer clue to its affinities than those which the exterior presents. The structure of the hinge characterises both families and genera, whilst the condition of the respiratory and locomotive organs may be to some extent inferred from the muscular markings. The margin of the shell on which the ligament and teeth are situated, is termed the hinge-line. It is very long and straight in Avicula and Arca, very short in Vulsella, and curved in most genera. The locomotive bivalves have generally the strongest hinges, but the most perfect examples are presented by Arca and Spondylus. The central teeth, those immediately beneath the wmbo, are called hinge (or cardinal) teeth; those on each side are /ateral teeth. Sometimes lateral teeth are developed, and not cardinal teeth (Alasmodon ; Kellia): more frequently the hinge-teeth alone are present. In young shells the teeth are sharp and well-defined ; in aged specimens they are often thickened, or eyen obliterated by irregular growth (Hippopodium) or the encroachment of the hinge-line (Pectun- culus). Many of the fixed and boring shells are edentulous.* The muscular impressions are those of the adductors, the foot and byssus, the siphons, and the mantle (see pp. 19, 20). a Se HT i vs Fig. 210. Left valve. ( Pecten v "1 tts.) Right valve. a, a, adductcr; p, pedal impression; m, palial line; 7, 'gamental margin; c, c, car- tilage ; e, e, anterior ears ; b, byssal sinus. The adductor impressions are usually simple, although the * The dentition of bivalve shells may be stated thus:—cardinal teeth, 2.3 or 2— - Meaning 2 in the right valve, 3 in the /e# ; lateral teeth 1—), 2-42, or 1 anterior and 1 posterior in the right valve, 2 anter-or and 2 posterior lateral teeth in the /¢ft valve. 402 MANUAL OF THE MOLLUSCA. : 7 muscles themselyes may be composed of two elements,* as in Cytherea chione (Fig. 14, p. 20) and the common oyster. The impression of the posterior adductor in Spondylus is double (Pl. XVI., Fig. 15). In Pecten varius (Fig. 210, a a), large independent impressions are formed by the two portions of the adductor, and in the left valve there is a third impression (p) produced by the foot, which in the byssiferous pectens is a simple conical muscle with a broad base. In the left valve of Anomia there are four distinct muscular impressions (Fig. 213). Of these, the small posterior spot alone is produced by the adductor, and corresponds with the solitary Fig. 211. Right valve. Fig. 212. Fig, 213. Left valve. impression in the right valve. The adductor itself (Fig. 212, a’) is double. The large central impression (p) is produced by the muscle of the plug (the equivalent of the byssal muscle in Pinna and Modiola). The small impression within the umbo (wu) and — the third impression in the disc (p’) (wanting in Placunomia) are caused by the retractors of the foot. The term monomyary, employed by Lamarck to distinguish the bivalves with one adductor, applies only to the Ostreide, part of the Aviculide, and to the genera Tridacna and Miilleria. The dimyary bivalves have a second adductor, near the anterior margin, which is small in Mytilus (Fig. 30), but large in Pinna. The. retractor muscles of the foot (already alluded to at p. 20) haye their fixed points near those of the adductors; the anterior — pair are attached within the umbones (Fig. 214, w wu), or nearer the adductor, as in Astarte and Unio (Fig. 209). The posterior pair (p’p') are often close to the adductor, and leaye no separate rey ae Pr * Compare the shell of modiola, Pl. XVII., Fig. 5, with the woodcut, Fig. 214. 7 Fig. 211. Right valve of Anomia ephippium, L. 1, ligamental process; s, sinus Fig. 213. Left valve; J, ligament pit. Fig. 212. Muscular system, from a drawing communicated by A. Hancock, Esq. 7, the foot; pl, the plug. The muscle p is generally described as a portion of the adductor ; but it is certain, from a comparison of this shell with Carolia and Placuna, that a' represents the entire adductor, and p the byssal muscle, CONCHIFERA. 4038 impression. The Unionide have two additional retractors of the foot, attached laterally behind the anterior adductors; in Leda, Solenella, and a few others, this lateral attachment forms a line extending from the anterior adductor backwards into the umbonal region of the shell. (See Pl. XVII., Figs. 21, 22.) In those shellfish like Pinna and the mussel, which are per- manently moored by a strong byssus, the foot (f/) serves only to mould and fix the threads of which it is formed. The fibres of the foot-muscles pass chiefly to the byssus (0), and besides these two additional muscles (pp) are developed. In Pinna, Fig. 214. Muscles of JJodiola, * Modiola, and Dreissena the byssal muscles are equal to the great adductors in size. In a few rare instances the muscles are fixed to promi- nent apophyses. The falciform processes of Pholas and Teredo (Pl. XXIII., Figs. 19, 26) are developed for the attachment of the foot-muscle; the posterior muscular ridge of Diceras and Cardilia resembles a lateral tooth, and in the extinct genus _ Radiolites both adductors were attached to large tooth-like pro- cesses of the opercular valve; but, as a rule, the muscles deposit * Fig. 214. Muscular system of Modiola modiotus, L., from a drawing communi- cated by A. Hancock, Esq. aa, anterior, a'a’, posterior adductors ; uu and p'p', pedai muscles ; pp, byssal muscles ; f, foot; 0, byssus; m, pailial line, 404 MANUAL OF THE MOLIUSCA. less shell than the mantle, and their impressions deepen with® x Age. “The pallial line (Fig. 214, m)1is produced by the muscular | fibres of the mantle-margin; it is broken up into irregular spots in the monomyary bivalves, and in Saxicava and Panopeea Norvegica. The siphonal impression, or pallial sinus (Fig. 14, p. 20), only exists in those shells which have retractile siphons; its depth is an index to their length. The large combined siphons of Mya (Fig. 207) are much longer than the shell; and those of some T'ellinide three or four times its length, yet they are com- pletely retractile. The small siphons of Cyclas and Dreissena cause no inflection of the pallial line. The form of the sinus is characteristic of genera and species. In the wmbonal area (within the pallial line) there are some- times furrows produced by the viscera, which may be distin- guished from the muscular markings by absence of polish and outline. (See Lucina, Pl. XIX., Fig. 6.) Fossil bivalves are of constant occurrence in all sedimentary rocks; they are somewhat rare in the older formations, but increase steadily in number and yariety through the secondary and tertiary strata, and attain a maximum of development in existing seas. Some families, like the Cyprinide and Lucinide are more ~ abundant fossil than recent ; whilst many genera, and one whole family (the ippuritide), haye become extinct. The determi- nation of the affinities of fossil bivalves is often exceedingly difficult, owing to the conditions under which they occur. Sometimes they are found in pairs, filled up with hard stone; and frequently as casts, or moulds of the interior, giving no trace of the hinge, and very obscure indications of the muscular markings. Casts of single valves are more instructive, as they afford impressions of the hinge.* Another difficulty arises from the frequent destruction of the nacreous or lamellar portion of the fossil bivalves, whilst the cellular layers remain. The Aviculide of the chalk have entirely — lost their pearly interiors; the Spondyli, Chamas, and Radiolites — are in the same condition, their inner layers are gone and no- vacancy left, the whole interior being filled with chalk. As it is the inner layer alone which forms the hinge, and alone receiyes the impressions of the soft parts, the true characters of — * These impressions may be conveniently aout with gutta-percha. M. Agassi x 4 may be seen in the Brit. Museum. [MJemoire sur les moules des Mollusques, vivans ot Yossiles, par L. Agassiz, Mem. Soc. Sc. Nat. Neuchatel, t. 2.] CONCHIFERA. 405 the shells could not be determined from such specimens. Our knowledge of the extinct Radiolite is derived from natural moulds of the interior, formed before the dissolution of the inner layer of shell, or from specimens in which this layer is replaced by spar. The necessities of geologists haye compelled them to pay very minute attention to the markings in the interior of shells, to their microscopic texture, and every other available source of comparison and distincticn. It must not, however, be expected that the entire structure and affinities of molluscous animals can be predicated from the examination of an internal mould or a morsel of shell, any more than that the form and habits of an extinct quadruped can be inferred from a solitary tooth or the fragment of a bone.* The systematic arrangement of the bivalyes now employed is essentially that of Lamarck, modified, however, by many recent observations. The families follow each other according to rela- tionship, and not according to absolute rank; the Veneridce are the highest organised, and from this culminating point the stream of affinities takes two courses, one towards the Myas, the other in the direction of the oysters; groups analogically reiated to the Tunicaries and Brachiopoda. ‘ SECTION A. ASIPHONIDA. a. Pallial line simple: Integro-pallalia. Fam. 1. Ostreidee. 4. Arcadee. 2. Aviculidee. 5. Trigoniade. 3. Mytilidee. 6. Unionidee. SECTION B. SIPHONIDA. 7. Chamidee. 11. Lucinidee. 8. Hippuritidee. 12. Cycladidee. 9. Tridacnidee. 13. Cyprinidie. 10. Cardiadee. b. Pallial line sinwated : Sinu-pallaha. 14. Veneridee. 18. Myacidee. 15. Mactridee. 19. Anatinidee. 16. Tellinidee. 20. Gastrocheenidee. 17. Solenidee. 21. Pholadidee. The characters which haye been most relied on for distin- * Etudes Critiques sur les Mollusques Fossiles, par L, Agassiz, Neuchatel, 1840. 406 MANUAL OF THE MOLLUSCA. euishing these groups and the genera of bivalyes are the fol- lowing, stated nearly in the order of their value :— 1. Extent to which the mantle-lobes are united. 2. Number and position of muscular impressions, Presence or absence of a pallial sinus. 4, Form of the foot. 5. Structure of the branchie. 6. Microscopic structure of the shell. (v. p. 31.) 7. Position of the ligament, internal or external. 8 9 Me . Dentition of the hinge. . Equality or inequality of the valves. 10. Regularity or irregularity of form. 11. Habit ;—free, burrowing or fixed. 12. Medium of respiration, fresh or salt water. A few exceptions may be found, in which one or other of these characters does not possess its usual vyalue.* Such in- stances serve to warn us against too implicit reliance on single characters. Groups, to be natural, must be based on the con- sideration of all these particulars—on ‘‘the totality of the animal organisation.” (Ovwen.) SECTION A.—ASIPHONIDA. Animal unprovided with respiratory siphons; mantle-lobes free, or united at only one point which divides the branchial from the exhalent chamber (cloaca); pallial impression simple. Shell usually pearly or sub-nacreous inside; cellular ex- ternally ; pallial line simple or obsolete. * 1. Cardita and Crassatella (Fam.13) have the mantle more open, whilst in /ridina (6), and especially in Dreissena (3) it is more closed than in the most nearly allied genera. 2. Mulleria (6) and Tridacna (9) are monomyary. 3. Leda (4) and Adacna (10) have a pallial sinus ; Anapa (16) has none. 4. The form of the foot is usually characteristic of the families; but sometimes it is adaptively modified. 5. Diplodonta (11) has four gills. 6. Pearly structure is variable even in species of the same genus. . 7. Crassatella (13) and Semele (16} have an internal ligament; in+Solenella and Jsoarca (4) it is external. 8. Anodon (16), Adacna, £erripes (10), and Cryptodon (11) are edentulous. 9. Corbula (18) and Pandora (19) are more inequivalve than their allies; Chama arcinella (7) is equivalve. 10. Hinnites (1), Atheria (6), Myochama and Chamostrea (19) are irregular. 1l. Pecten is free, byssiferous, or fixed: Arca free or byssiferous. This character varies with age and locality in the same species. It does not always depend on the form of the foot, as Lithodomus and Ungulina—boring shells—have the foot like Mytilus and Lucina. ; 12. Novaculina is a river Solen, and Scaphula a fresh-water Arca. . i a Se A ee m ~ CONCHIFERA, 407 FAMILY I.—OSsTREIDA. Shell inequivalve, slightly inequilateral, free or adherent, resting on one valve; beaks central, straight; ligament in- ternal; epidermis thin ; adductor impression single, behind the centre; pallial line obscure; hinge usually edentulous. Animal marine; mantle quite open; very slightly adherent to the edge of the shell; foot small and byssiferous, or obsolete; gills crescent-shaped, 2 on each side; adductor muscle composed of two elements, but representing only the posterior shell-muscle of other bivalves. The union of the Ostreide and Pectinide, as proposed by the authors of the ‘‘ History of British Mollusca,” has not proyed satisfactory. ‘The genus Ostrea stands quite alone, and distinct from all the Pectinide in the structure of its gills, which are like those of Avicula, and by resting on itsle/t valve. The shell also is more nacreous than that of the scallops OsTREA, L.—OYSTER. Synonyms, Amphidonta and Pyecnodonta, Fischer. Peloris, Poli. Type, O. edulis, L. Example, O. diluviana, Pl. XVI., Fig. 1. Shell irregular, attached by the left valye ; upper valve flat or concave, often plain; lower conyex, often plaited or foliaceous, and with a prominent beak; ligamental cavity triangular or elongated; hinge toothless; structure sub- nacreous, laminated, with prismatic cellular substance between the margins of the laminze. Animal with the mantle-margin double, finely fringed; gills nearly equal, united posteriorly to each other and the mantle- lobes, forming a complete branchial chamber ; lips plain ; palpi triangular, attached ; sexes distinct.* Distribution, 70 species. Tropical and temperate seas. Norway, Black Sea, &c. Fossil, 200 species. Carb. —. United States, Europe, India. The interior of recent oyster-shells has a slightly nacreous lustre; in fossil specimens an irregular cellular structure is often very apparent on decomposed or fractured surfaces. Fossil oysters which have grown upon Ammonites, Trigonice, &e., frequently take the form of those shells. In the ‘‘cock’s-comb” cysters both valves are plaited; O. diluviana sends out long root-like processes from its lower - * The course of the alimentary canal in the common oyster is incorrectly repre- sented by Poli, and copied in the Crochard ed. of Cuvier, a 408 MANUAL OF THE MOLLUSCA. valve. The ‘‘tree-oyster” (Dendrostrea, Sw.) grows on the root of the mangrove. Oyster shells become very thick with age, especially in rough water; the fossil oyster of the Tagus (O. longirostris) attains a length of two feet. The greatest enemy of oyster-banks is a sponge (Cliona), which eats into the valves, both of dead and living shells; at first only small round holes, at irregular intervals, and often disposed in regular patterns, are visible; but ultimately the shell is completely mined and falls to pieces. Natural oyster-banks usually occur in water several fathoms deep; the oysters spawn in May and June, and the fry (‘‘ spats”) are extensively collected and removed to artificial grounds, or tanks, where the water is very shallow; they are then called ‘‘ natives,” and do not attain their full growth in less than five or seven years, whilst the ‘‘ sea-oysters ” are full-grown in four years. Native oysters do not breed freely, and epmetimes many die in the spawning season; they are also liable to be killed by frost. The season isfrom August 4 to May 12. From 20,000 to 30,000 bushels of ‘‘ natives”? and 100,000 bushels of sea-oysters are annually sent to the London market. Many other species of oy es are eaten in India, China, Australia, &c. ‘‘ Green oysters” are those which have fed on conferve in the tanks. \) Sub-genera. Gryphcea, Lamarck. 'G. incurva, Sby. (section), Fig. 215. Free, or very slightly at- / tached; left valve with a promi- nent, incurved umbo; right valve ——LY small, concave. Fossil, 30 species. Fig. 215. Gryphaa. Lias — Chalk. Europe, India. Exogyra, Sby. EE. conica, Pl. XVI., Fig. 2. Shell chama- shaped, attached by the left valve; umbones sub-spiral, turned to the posterior side (i.e. reversed); right valve opercular. Fossil, 46 species. Li. Oolite — Chalk. United States; Hurope. Dimya (Deshayesana), Rouault, 1859. Mém. Soc. Géol. b. ITT. 471, t. 15. Fig. 3. Z. Eocene, Paris. The figure is most like an oyster, and the ‘‘ second adductor impression,” on account of which it is named Dimya, is rather like the small anterior scar in Pecten (Fig. 210). »AnomiA, L. Etymology, anomios, unequal. Example, A. Achzeus, Pl. XVI., Fig. 3. Synonyms, Fenestrella, Bolten ; Cepa, Humph. ia Koch. : Shell sub-orbicular, yery yariable, translucent, and slightly CONCHIFERA. 403 pearly within, attached by a plug passing through a hole or notch in the right valve: upper valve convex, smooth, lamellar or striated ; interior with a sub-marginal cartilage-pit, and four muscular impressions, 3 sub-central, and one in front of the cartilage (see Fig. 213, p. 402): lower valve concave, with a deep, rounded notch in front of the cartilage process; disk with a single (adductor) impression. Animal with the mantle open, its margins with a short double fringe; lips membranous, elongated; palpi fixed, striated on both sides; gills 2 on each side, united posteriorly, the outer laminz incomplete and free ; foot small, cylindrical, subsidiary to a lamellar and more or less calcified byssal plug, attached to _ the upper valve by three muscles; adductor muscle behind the byssal muscles, small, composed of two elements; sexes dis- tinct; ovary extending into the substance of the lower mantle- lobe. In A. pernoides, from California, there is an anterior (pedal) muscular impression in both valves. **There is no relationship of affinity between Anomia and _Terebratula, but only a resemblance through formal analogy; the parts which seem identical are not homologous.”’ (Forbes.) The Anomiz are found attached to oysters and other shells, and frequently acquire the form of the surfaces with which their growing margins are in contact. They are not edible. Distribution, 20 species. North America, Britain, Black Sea, India, Australia, West America, Icy sea. Low water — 100 fathoms. Fossil, 36 species. Oolite —. Chili, United States, Europe, India. Sub-genera. Placunomia (Cumingii), Broderip. Synonym, Pododesmus, Phil. P. macroschisma, Pl. XVI., Fig. 4. Upper valve with only two muscular impressions; the pedal scar radiately striated ; the byssal plug is often fixed in the lower valve, and its muscle becomes (functionally) an adductor. Dis- tribution, 13 species. West Indies, Britain (P. patelliformis), New Zealand, California, Behring’s Sea, Ochotsk. — 650 fathoms. __ Limanomia (Grayana), Bouchard. Shell eared like Lima. Fossil, 4 species. Devonian; Boulonnais, China? PiLacuna, Solander.—Window-Shell. : Etymology, plakous, a thin cake. Example, P. sella, Pl. XVI., Fig. 5. Shell suborbicular, compressed, translucent, free, resting on T 410 MANUAL OF THE MOLIe 0A. the right valve; hinge area narrow and obscure; cartilage supported by two diverging ridges in the right valve and cor- responding grooves in the left; muscular impressions double, the larger element round and central, the smaller distinct and crescent shaped, in front of it. The Placune are very closely allied to Anomia ; and many intermediate forms may be traced. The shell of each consists entirely of sub-nacreous, plicated laminz, peculiarly separable, and occasionally penetrated by minute tubuli. (Carpenter.) P. sella, called, from its shape, the ‘‘ saddle-oyster,” is remarkably striated. In P. placenta, Pl. XVI., Fig. 6, the anterior carti- lage ridge is only half as long as the other, which appears to be connected with the economy of the shell when young; in speci- mens 1 inch across, there is a pedal impression below the cartilage grooves of the upper valve, and a shallow sinus in the margin of the lower valve, indicating a slight byssal attach- ment at that age. Placuna* is essentially like Anomia, haying the generative system attached to the right mantle-lobe, and the ventricle exposed. The mantle-margin is cirrated, and furnished with a curtain, asin Pecten; the foot is tabular and extensile, but has no distinct muscles except the small one, whose existence in P. placenta (Pl. XVI., Fig. 6) we had predicated from examina- tion of the shell.+ The small muscular impressions before and in the rear of the adductor are produced by suspensors of the gills. Distribution, 4 species. Scinde, North Australia, China. Sub-genera. Carolia, Cantraine, 1835 (after Prince Charles Bonaparte). Synonym, Hemiplacuna, G. Sby. Type, C. placu- noides, Pl. XVI., Fig. 7. Shell like Placuna ; hinge, when young, like Anomia, with a byssal plug passing through a small deep sinus in front of the cartilage process, which is closed in theadult. Distribution, 3 species. (British Museum), Tertiary, — - Egypt; America? Placunopsis, Morris and Lycett. P. Jurensis, Roemer. Sub-_ orbicular, upper valve convex, radiately striated, or taking the — form of the surface to which it adheres; lower valve flat; lga-_ mental groove sub-marginal, transverse; muscular impression — large, sub-central. Fossil 4 species. Lower Oolites, Hurope. Placenta, Retzius. Cartilage grooves slightly divergent, the posterior one the longer of the two; muscular impression sub central. * Original figures and descriptions will be found in the An. Nat. Hist. 1855, p. 22. + This organ appears to represent the byssal-sheath of Anomia, rather than the foot &s there is no other opening for the passage of a yyssus, inner pendent like a curtain CONCHIFERA. 4i}t PrcTEN, O. F. Miiller. Scallop. 7 Etymology, pecten, a comb. Type, P. maximus (Janira, Schum.) Synonyms, Argus, Poli. Discites, Schl. Amusium, Muhlfeldt. Shell sub-orbicular, regular, resting on the right valve, usually ornamented with radiating ribs; beaks approximate, eared; anterior ears most prominent; posterior side a little oblique ; right valve most conyex, with a notch below the front ear; hinge- margins straight, united by a narrow ligament; cartilage internal, in a central pit; adductor impression double, obscure ; pedal impression only in the left valve, or obsolete (Fig. 210). Animal with the mantle quite open, its margins double, the (m) finely fringed; at its base a row of conspicuous round black eyes (ocelli) sur- rounded by tentacular fila- ments; gills (br) exceed- 7% ingly delicate, crescent- shaped, quite disconnected posteriorly, having separate excurrent canals; lips folia- Be ceous; palpi truncated, plain outside, striated within; foot finger-like, grooved, byssiferous in the young. The Scallop (P. maximus) and ‘‘quin” (P. opercularis) are esteemed delicacies ; the latter covers extensive banks, especially on the north and west of Ireland, in 15 to 25 fathoms water. The scallop ranges from 3—40 fathoms; its bodyis bright orange, or scarlet, the mantle fawn-colour, marbled with brown; the shell is used for ‘‘ scalloping” oysters, formerly it was em- ployed as a drinking-cup, and celebrated as such in Ossian’s ‘hall of shells.” An allied species has received the name of “St. James’s shell” (P. Jacobeus); it was worn by pilgrims to the Holy Land, and became the badge of several orders of knighthood.t Most of the Pectens spin a byssus when young, and some, hike P. varius, do so habitually ; P. niveus moors itself to the ) : ' fronds of the tangie (Laminaria). * The Pectens do not open so wide as here represented; their “ curtains” remain in contact at one point on the posterior side, separating the branchial from the exhalent currents. + When the monks of the ninth century converted the fisherman of Gennesaret into a Spanish warrior, they assigned him the scallop-shell for his “ cognizance.” (Moule’s “ Heralury of Fish.’’) T2 a 412 MANUAL OF THE MOLLUSUA. The Rey. D. Landsborough observed the fry of P. opercularia,- when less than the size of asixpence, swimming in a pool of sea-water left by the ebbing of the tide. ‘‘ Their motion was rapid and zig-zag; they seemed, by the sudden opening and closing of their valves, to have the power of darting lke an arrow through the water. One jerk carried them some yards, and then by another sudden jerk they were off in a moment on a different tack.” The shell of Pecten and the succeeding genera consists almost exclusively of membranous lamin, coarsely or finely corru- gated. Itis composed of two very distinct layers, differing in colour (and also in texture and destructibility), but haying essentially the same structure, Traces of cellularity are some- times discoverable on the external surface; P. nobilis has a distinct prismatic-cellular layer externally. (Carpenter.) Sub-genera, Neithea, Drouet, Vola, Klein. P. quinque- costatus and other fossil species with concayo-convex valves and distinct hinge-teeth ; the inner layers of these shells are wanting in all specimens from the English chalk. Pallium, Schum. P. plica, Pl. XVI., Fig. 8. Hinge obscurely toothed. Hinnites (Cortesii) Defr. P. pusio, Pl. XVI., Fig. 10. Shell regular and byssiferous when young; afterwards cementing its lower valve and becoming more or less irregular. Distribution, 2 species. Fossil, Trias? Upper Greensand —, Europe. Hemipecten, A. Adams. H. Forbesianus, Pl. XVI., Fig. 9. Shell hyaline, posterior ears obsolete, anterior prominent; right valve flat, byssal sinus deep; structure permeated bye microscopic tubuli, as in Lima. a Amusium, Klein. Shell nearly equivalved, gaping in front and behind; smooth outside, generally marked with radiating grooves taeile. a Distribution, 176 species. World-wide; Nova-Zembla—Cape- Horn ; — 200 ‘fathoms. “ Fossil, 450 species (including Ayiculo-pecten). Carb.—. World-wide. - Lima, Bruguiere. Etymology, lima, a file. e | Example, Li. squamosa, Pl. XVI., Fig. 11. (Ostrea lima, L.}_ Synonyms, Plagiostoma (Llnwyd), Sby. P. cardiforme, Pl. XVI, Fig. 12. ; CONCHIFERA 413 straight, gaping, posterior rounded, usually close; umbones apart, eared; valves smooth, punctate-striate, or radiately ribbed and imbricated; hinge area triangular, cartilage pit central; adductor impression lateral, large, double; pedal scars 2, small. Animal, mantle-margins separate, inner pendent, fringed with long tentacular filaments, ocelli inconspicuous; foot finger-hke, grooved; lips with tentacular filaments, palpi small, striated inside; gills equal on each side, distinct. The shell is always white; its outer layer consists of coarsely- plicated membranous lamellz; the inner layer is perforated by minute tubuli, forming a complete network. (Carpenter.) The Limas are either free or spin a byssus; some make an artificial burrow when adult, by spinning together sand or coral- fragments and shells, but the habit is not constant. (Forbes.) The burrows of Z. hians are several times longer than the shell, and closed at each end. (Charlesworth.) ‘‘This species is pale or deep crimson, with an orange mantle; when taken out of its nest it is one of the most beautiful marine animals to look upon, it swims with great vigour, like the scallop, by opening and closing its valves, so that it is impelled onwards or upwards in a succession of jumps. The filaments of the fringe are easily broken off, and seem to live many hours after they are detached, twisting themselves like worms.” (Landsborough.) ZL. spinosa has conspicuous ocelli, and short filaments. Sub-generu, Limatula, 8. Wood. L. sub-auriculata, Pl. X VI., Fig. 13. Valves equilateral; 8 species. Greenland—Britain. Fossil, Miocene—. Europe. Limea, Bronn. L. strigilata, Pl. XVI. Fig. 14.* Hinge minutely toothed. Fossil, 4 species. Lias—Pliocene. The recent Limca? Sarsii (Lovén), Norway (=U. crassa of the Aigean ?) has the mantle-border plain. Some of the larger recent species have obscure lateral teeth. Distribution, 20 species. Norway, Britain, West Indies, Canaries, India, Australia; 1—150 fathoms. The largest living species (LZ. excavata, Chemn.) is found on the coast of Norway. _ Fossil, 200 species. Carb.? Trias—. United States, Europe, India. The'so-called Plagiostoma spinosum is a Spondylus. SPONDYLUS (Pliny) L. Thorny-oyster. Type, 8. geedaropus, L. Example, 8. princeps, Pl. XVI., Fig. 15 * After Bronn; the figure in Brocchi does not show the teeth. 414 MANUAL OF THE MOLLUSOA. Synonyms, Dianchora, Sby. Podopsis, Lam. Pachytes, Defr. Shell irregular, attached by the right valve, radiately ribbed, spiny or foliaceous; umbones remote, eared; lower valve with a triangular hinge-area, cartilage in a central groove, nearly or quite covered; hinge of two curved interlocking teeth in each valve ; adductor impression double. Animal, with the mantle open and gills separate, as in Pecten ; lips foliaceous, palpi short ; foot small, cylindrical, truncated. In aged specimens the circular portion of the muscular scar -exhibits dendritic vascular markings. The lower valve is always most spiny and least coloured ; in some species (like S. imperialis) the shell is scarcely, if at all, attached by its beak or spines. The inner shell-layer is very distinct from the outer, and always wanting in fossil specimens from calcareous rocks, then called Dianchore. Specimens from the Miocene of St. Domingo, which have lost this layer, contain a loose mould of the original interior. Water-cayities are common in the inner layer, the border of the mantle haying deposited shell more rapidly than the umbonal portion. (Owen, Mag. Nat. Hist. 1838, p. 409.) Distribution, 68 species. West Indies, Canaries, Mediter- ranean, India, Torres Straits, Pacific, West America :—105 fathoms. Fossil, 80 species. Carb—. Europe, United States, India. Sub-genus, Pedum, Brug. PP. spondyloides, Pl. XVL., Fig. 16. Shell thin, smooth, compressed, attached by a byssus passing through a deep notch in the right valve. Inhabits coral-reefs, ehers it is found half-embedded ; Red Sea, Indian Ocean, Mauritius, Chinese Seas. PLICATULA, Lamarck. Etymology, plicatus, plaited. Type, P. cristata, Pl. XVI., Fig. 17. Shell irregular, attached by the umbo of the right valve; valve smooth or plaited; hinge-area obscure; cartilage quite — internal; hinge-teeth, two in each valve; adductor scar simple. — Animal resembles spondylus. Distribution, 9 species. West Indies, India, Philippines Australia, West America. Fossil, 40 species. Trias—. United States, Europe, Alge india. r P. Mantelli (Lea) Alabama, has the valves eared, CONCHIFERA. 415 Famity IJ.—Avicutipm. Wing-shells. Shell inequivalve, very oblique, resting on the smaller (right) valve, and attached by a byssus; epidermis indistinct: outer layer prismatic-cellular (Fig. 217), in- terior nacreous; posterior muscular im- pression large, sub-central, anterior. small, within the umbo ; pallial line, irregularly dotted; hinge-line straight, elongated ; umbones anterior, eared, the posterior ear wing-like ; cartilage contained in one or several grooves; hinge edentulous, or obscurely toothed. Animal with the mantle-lobes free, their margins fringed ; foot small, spinning a byssus; gills two _ on each side, crescent-shaped, entirely free (Desh.) or united to each other posteriorly, and to the mantle (as in the Oyster, and not as in Pecten). The wing-shells, or pearl-oysters, are natives of tropical and temperate seas; there are no living species in northern latitudes, where fossil forms are very numerous. Fig. 217. Pinna.* AVIcULA (Klein), Bruguiere. Etymology, avicula, a little bird. Type, A. hirundo, Pl. XVI., Fig. 18. Shell obliquely oval, very inequivalve; right valve with a byssal sinus beneath the anterior ear; cartilage pit single, oblique; hinge with one or two small cardinal teeth, and an elongated posterior tooth, often obsolete; posterior muscular impression (adductor and pedal) large, sub-central; anterior (pedal scar) small, umbonal. Animal (of meleagrina) with mantle-lobes united at one point by the gills, their margins fringed and furnished with a pendent curtain; curtains fringed in the branchial region, plain behind ; foot finger-like, grooved; byssus often solid, cylindrical, with an expanded termination ; pedal muscles four, posterior large in front of the adductor; adductor composed of two elements ; retractors of the mantle forming a series of dots, and a large spot near the adductor; lips simple; palpi truncated; gills equal, crescentic, united behind the foot. (British Museum.) * The cellular structure may be seen with a hand-lens, in the thin margin of the shell, by holding it up to the light ; or on the edges of broken fragments. 416 MANUAL OF THE MOLLUSCA. Distribution, 25 species. Mexico, South Britain, Mediter- ranean, India, Pacific :—20 fathoms. Fossil, 300 species. Lower Silurian —. World-wide. Sub-genera Maleagrina, Lam. Margaritophora, Muhlfeldt. M. margaritifera, Pl. XVI., Fig. 19. The ‘‘ pearl-oysters” are less oblique than the other avicule, and their valves are flatter and nearly equal; the posterior pedal impression is blended with that of the great adductor. They are found at Madagascar, Ceylon, Swan River, Panama, &c. Manillais the chief port to which they are taken. There are three principal kinds, which are worth from £2 to £4 per cwt.:—1. The silver-lipped, from the Society Islands, of which about twenty tons are annually im- ported to Liverpool. 2. The black-lipped, from Manilla, of which thirty tons were imported in 1851. 3. A smaller sort from Panama, 200 tons of which are annually imported; in 1851 a single vessel brought 340 tons. (T.C. Archer.) These shells afford the ‘‘ mother-o’-pearl” used for ornamental pur- poses ; and the “‘ oriental” pearls of commerce (p. 30, 31). Mr. Hope’s pearl, said to be the largest known, measures 2 inches long, 4 round, and weighs 1,800 grains. Pearl-oysters are found in about 12 fathom water; the fisheries of the Persian Gulf and Ceylon have been celebrated from the time of Pliny. Malleus, Lam. M. vulgaris, Pl. XVI., Fig. 20. The ‘‘hammer- oyster”? is remarkable for its form, which becomes extremely elongated with age; both ears are long, and the umbones central. When young it is like an ordinary Avicula, with a deep byssal notch in the right valve. 6 species. China, Australia. Vulsella, Lam. Y. lingulata, Pl. XVI., Fig. 21. Synonym, Reniella, Sw. Shell, oblong, striated, sub-equivalve; umbones straight, earless. Often found imbedded in living sponges. Distribution, 7 species. Red Sea, India, Australia, Tasmania. Fossil, 7 species. U. Chalk —. Britain, France. Pteroperna, Lycett, 1852. P.costatula, Desl. Shell with a long posterior wing; hinge-line bordered by a groove; anterior teeth numerous, minute; posterior one or two, long, nearly parallel with the hinge-margin. Jossi/,3 species. Bath oolite ; Britain, France. ? Aucella (Pallasii), 1846. Very inequivalve; left umbo pro- minent, earless; right valve small and flat, with a deep sinus beneath the small anterior ear. Fossil, 4 species, Permian — Gault. Europe. ‘In A. cygnipes we find no trace of prismatic cellular structure or nacre, but the coarsely corrugated and somewhat tubular structure of the Pectens.” (Carpenter.) - CUNCHIFERA. 417 Ambonychia (bellistriata), Hall, 1847. Nearly equivalve, gibbose, oblique, obtusely winged. A. vetusta (Inoceramus, Sby.) is concentrically furrowed; the right valve has a small anterior ear (usually concealed) separated by a deep and narrow sinus. fossil, 12 species. Lower Silurian — Carb. United States, Europe. - P Cardiola (interrupta), Broderip, 1844. Equivalvye, gibbose, obliquely oval, radiately ribbed; beaks prominent; hinge-area short and flat. fossil, 17 species. Upper Silurian — Dey. United States, Europe. ? Hurydesma (cordata), Morris; Devonian? New South Wales. Shell equivalve, sub-orbicular, ventricose, very thick near the beaks; ligimental area long, wide, sub-internal; byssal groove close to the umbo ; right valve with a large, blunt hinge-tooth ; adductor impression single, placed anteriorly; pallial line dotted. Pterinea (leevis), Goldf. 1832. Shell thick, rather inequivalve, very oblique and broadly winged ; beaks anterior; sinus shallow ; hinge-area long, straight, narrow, striated lengthwise; ante- rior teeth few, radiating; posterior teeth laminar, elongated ; anterior (pedal) scar deep, posterior (adductor) impression large, very eccentric. fossil, 32 species. Lower Silurian — Carb. United States, Europe, Australia. Pteronites (angustatus) M‘Coy, 1844, is thinner and has the teeth, &c., less developed. Monotis, Bronn, 1830. M. Salinaria, Schl. TZ'vrias, Hallein. Obliquely oval, compressed, radiated; anterior side short, rounded ; posterior slightly eared. Synonym, ? Halobia (salinarum) Br. 1830. Trias, Hallstadt. Semi-oyal, radiated, compressed, with a shallow sinus in front ; hinge-line long and straight. PosmbonomyA, Bronn. Synonym, Posidonia, Br. 1838 (not Kénig). Poseidén, Nepture. Type, P. Becheri, Pl. XVI., Fig. 22. Shell thin, equivalvye, compressed, earless, concentrically furrowed ; hinge-line short and straight, edentulous. Fossil, 50 species. Lower Silurian — Trias. United States, Kurope. ?P AVICULO-PECTEN, M‘Coy, 1852. Type, Pecten granosus, Sby. Min. Con. t. 574. Shell inequivalve, sub-orbicular, eared; hinge-areas flat, with seyeral long, narrow cartilage furrows, slightly oblique on each side of the umbones ; right valve with a deep and narrow byssal s.nus beneath the anterior ear; adductor impression large, tT 3 418 MANUAL OF THE MOLLUSCA. simple, sub-central; pedal scar small and deep, beneath the 9 umbo. b Fossil (see Pecten). Lower Silurian — Carb. Spitzbergen — Australia. GERVILLIA, Defrance. Etymology, dedicated to M. Gerville, a French naturalist. Example, G. anceps, Pl. XVII., Fig. 1. q Shell iike Avicula; elongated; anterior ear small, posterior wing-like; area long and flat, cartilage pits several, wide apart ; hinge-teeth obscure, diverging posteriorly. Fossil, 37 species. Carb. — Chalk. Europe. Sub-genus? Bakewellia, King. B. ceratophaga, Schl. Fossil, 5 species. Permian, Britain, Germany, Russia. Shell small, inequiyalye, cartilage pits 2—5; hinge with anterior and pos- terior teeth; anterior muscular impression and pallial line — distinct. PERNA, Bruguiere. Etymology, perna, a shell-fish (resembling a gammon), Pliny. Synonyms, Melina, Retz. Isognomon, Klein. Pedalion, Solander. Type, P. ephippium, L. Pl. XVII., Fig. 2. Shell nearly equivalve, compressed, sub-quadrate ; area wide, cartilage pits numerous, elongated, close-set; right valve with a byssal sinus; muscular impression double. The Pernas vary in form lke the Avicule ; some are very oblique, some very inequivalve, and many fossil species have the posterior side produced and wing-like. In some Tertiary Pernas the pearly layer is an inch thick. 3 Distribution, 18 species. Tropical seas; West Indies — India — — West America. Fossil, 30 species. Trias —. United States, Chili, Europe. Sub-genera, Crenatula, Lamk. C. viridis, Pl. XVI., Fig. 24. Shell thin, oblong, compressed ; byssal sinus obsolete; cartilage pits shallow, crescent-shaped. Distribution, 8 species, North Africa, Red Sea — China; in sponges. fossil, 4 species. Hypotrema, D’Orb, 1853. H. rupellensis (= ? Pulvinites Adansonii, Defrance, 1826); Coral-rag, Rochelle. Shell oblong, inequivalye; right valve flat or concaye, with a round byssal foramen near the hinge; left valve conyex, with a muscular impression near the umbo; hinge-margin broad, curyel, with about twelve close-set transverse cartilage grooves. ton CONCHIFERA. 419 INOCERAMUS, Sowerby (1814). Etymology, is (inos), fibre, keramos, shell. Example, I. sulcatus, Pl. XVIL., Fig. 3. Synonym, Catillus, Brongn. Shell inequivalye, ventricose, radiately or concentrically furrowed, umbones prominent; hinge-line straight, elongated ; cartilage pits transverse, numerous, close-set. This genus differs from Perna chiefly in form. J. involutus has the left valve spiral, the right opercular. J. Cuvier attains the length of a yard. Large flat fragments are common both in the chalk and flints, and are often perforated by the Cliona. Hemispherical pearls haye been found developed from their inner surface, and spherical pearls of the same prismatic-cellular structure occur detached, in the chalk. (Wetherell.) The Jno- cerami of the gault are nacreous. Fossil, 75 species. ? Silurian — Chalk. South America, United States, Europe, Algeria, Thibet. Pinna, L. Etymology, pinna, a fin or wing. Type, P. squamosa, Pl. XVI., Fig. 23. Shell equivalve, wedge-shaped; umbones quite anterior ; posterior side truncated and gaping; ligamental groove linear, elongated; hinge edentulous; anterior adductor scar apical, posterior sub-central, large, ill-defined; pedal scar in front of posterior adductor. Animal with the mantle doubly fringed; foot elongated, grooved, spinning a powerful byssus, attached by large triple muscles to the centre of each valve; adductors both large; palpi elongated ; gills long. Distribution, 30 species. United States, Britain, Mediter- ranean, Australia, Pacific, Panama. Fossil, 60 species. Devonian —. United States, Europe, South India. The shell of the Pinna attains a length of two feet; when young it is thin, brittle, and translucent, consisting almost entirely of prismatic cell-layers; the pearly lining is thin, divided, and extends less than half-way from the beak. Some fossil Pinas crumble under the touch into their component fibres. The living species range from extreme low water to 60 fathoms ; they are moored vertically, and often nearly buried in sand, with knife-like edges erect. The byssus has sometimes been mixed with silk, spun, and knitted into gloves, &ce. (Brit. 420 MANUAL OF THE MOLLUSCA. rs Mus.} A little crab which nestles in the mantle and gills of the Pinna, was anciently believed to have formed an alliance with the blind shell-fish, and received the name of Pinna-guardian (Pinnoteres) from Aristotle; similar species infest the Mussels and Anomic of the British coast. Sub-genus, Trichites (Plott), Lycett. T. Plotti, Llhwyd. (‘‘ Pinnigene,” Saussure.) Shell thick, imequivalve, somewhat irrecular, margins undulated. Fossil, 5 species. Oolitic strata of England and France. “Fragments an inch or more in thick- ness are common in the Cotteswold-hills; full-grown individuals are supposed to have measured a yard across. Faminty IIlI.—MytTitipz. Mussels. Shell equivalve, oval or elongated, closed, umbones anterior, epidermis thick and dark, often filamentose; ligament mternal, sub-marginal, very long; hinge edentulous; outer shell layer obscurely prismatic-cellular ;* inner more or less nacreous; pallial line simple; anterior muscular impression small and narrow, posterior large, obscure. Animal marine or fluviatile, attached by a byssus; mantle- lobes united between the siphonal openings; gills two on each side, elongated, and united behind to each other and to the mantle, dorsal margins of the outer and innermost laminee free ; foot cylindrical, grooved. . The members of this family exhibit a propensity for conceal- ment, frequently spinning a nest of sand and shell-fragments, burrowing in soft substances, or secreting themselves in the burrows of other shells. Mytiuvus, L. Sea-mussel. Example, M. smaragdinus, Pl. XVII., Fig. 4. Shell wedge-shaped, rounded behind; umbones terminal, — pointed ; hinge-teeth minute or obsolete ; pedal muscular im- ~ pressions two in each valve, small, simple, close to the adductors. Animal with the mantle-margins plain in the anal region, and projecting slightly; branchial margins fringed; byssus strong and coarse; gills nearly equal; palpi long and pointed, free. The common edible mussel frequents mud-banks which are uncovered at low-water; the fry abound in water a few fathoms deep; they are full-grown in asingle year. From some un- * A thin layer. of minute cells may frequently be detected immediately under the epidermis. Carpenter.) CONCHIFERA. 421 known cause they are at times extremely deleterious. The consumption of mussels in Edinburgh and Leith is estimated at 400 bushels (— 400,000 mussels) annually ; enormous quan- tities are also used for bait, especially in the deep sea fishery, for which purpose thirty or forty millions are collected yearly in the Firth of Forth alone. (Dr. Knapp.) Mussels produce small and inferior pearls. At Port Stanley, Falkland Islands, Mr. Macgillivray noticed beds of mussels which were chiefly dead, being frozen at low-water. WM. bilocularis (Septifer, Recluz) has an umbonal shelf for the support of the anterior adductor, like Dreissena ; it is found at Mauritius and Australia. M. exustus (Brachydontes, Sw.) has the hinge-margin denti- culated continuously. Distribution, 65 species. World-wide. Ochotsk, Behring’s Sea, Russian Ice-meer; Black Sea, Cape Horn, Cape, New Zealand. Fossil, 100 species. Silurian —. United States, Europe, South India. ? MyAtina, Koninck, 1842. Types, M. Goldfussiana, Kon. Carb. M. acuminata, Sby. Permian. Shell equivalve, mytili-form; beaks nearly terminal, septi- ferous internally; hinge-margin thickened, flat, with several longitudinal cartilage-grooyes; muscular impressions two; pallal line simple. Fossil, 6 species. Carb. — Permian. Europe. The liga- mental area resembles that of the recent Arca obliquata, Chemn. India. MoprionA, Lam. Horse-mussel. Etymology, modiolus, a small measure, or drinking-vessel. Example, M. tulipa, Pl. XVII., Fig. 5. M. modiolus, p. 403, Fig. 214. Shell oblong, inflated in front; umbones anterior, obtuse; hinge toothless; pedal impressions three in each yalye, the central elongated ; epidermis often produced into long beard- like fringes. Animal with the mantle-margin simple, protruding in the branchial region; byssus ample, fine; palpi triangular, pointed. The Modiole are distinguished from the Mussels by their habit of burrowing, or spinning a nest. Low water—100 fathoms. 422 MANUAL OF THE MOLLUSCA. Distribution, 70 species, chiefly tropical; MZ. modiolus, Arctic seas — Britain. Fossil, 150 species. Silurian? Lias —. United States, Europe, Thibet, South India. Sub-genera. Lithodomus, Cuy. M. lithophaga, Pl. XVIL, — Fig. 7. Shell cylindrical, inflated in front, wedge-shaped behind; - epidermis thick and dark; interior nacreous.* Distribution, 40 species. West Indies — New Zealand. Fossil, 35 species. Carb. —. Europe, United States. The ‘‘date-shell” bores into corals, shells (Fig. 25, p. 34), and the hardest limestone rocks ; its burrows are shaped like the shell, and do not admit — of free rotatory motion. The animal, which is eaten in the © Mediterranean, is ike a common mussel; in Z. patagonicus the siphons are produced. Like other burrowing shell-fish, they are luminous. Perforations of Lithodomi in limestone cliffs, and in the columns of the Temple of Serapis at Puteoli, have afforded conclusive evidence of changes in the level of sea- coasts in modern times. (Lyell’s ‘‘ Principles of Geology.”’) Crenella, Brown. O. discors, Pl. XVII., Fig. 8. (Lanistes, Sw. Modiolaria, Beck.) Shell short and tumid, partly smooth, and partly ornamented with radiating striz; hinge-margin crenulated behind the ligament; interior brilliantly nacreous. Animal with the anal tube and branchial margins prominent. Distribution, 24 species. Temperate and arctic seas; Nova Zembla, Ochotsk, Britain, New Zealand. Low water — 40 fathoms. Spinning a nest, or hiding amongst the roots of sea- — weed and corallines. JJ. marmorata, Forbes, burrows in the test of Ascidia. Fossil, 12 species. Upper Greensand —. Europe. a Modiolarca (trapezina), Gray ; Falkland Islands — Kerguelen, attached to floating sea-weed ; mantle-lobes united, pedal open- ing small, foot with an expanded sole, front adductor round. M. ? pelagica, Pl. XVII., Fig. 6, is found burrowing in floating blubber, off the Cape. (Forbes.) 2 living species. ; ? Mytilimeria (Nuttallii), Conrad. Shell irregularly oval, thin, _ edentulous, gaping posteriorly ; umbones sub-spiral; ligament short, semi-internal. Distribution, California; animal gre- garious, forming a nest. Modiolopsis (mytiloides), Hall, 1847 ( = Cypricardites, part, Conrad. Lyonsia, part, D’Orb.). Shell like modiola, thin and smooth, front end somewhat lobed; anterior adductor scar > * The outer shell-layer has a tubular structure; the tubes are excessively minute, celdom branching, oblique and parallel. ‘Carpenter.) CONCHIFERA. 425 large and oval. fossil, 15 species. Silurian, United States, Europe. ? Orthonotus (pholadis), Conrad. Lower Silurian, New York. Shell elongated, margins parallel, umbones anterior, back plaited.* Myrina, Adams. Modiola pelagica, has the mantle open; the shell is peculiar from the large size of the anterior muscular impression; and the subcentral umbones distinguish it from Modiolarca. Hoplomytilus (crassus), Sdbgr. Devonian, Nassau. Shell with a muscular plate in the umbo, hke Septifer. The Mytilus squamosus, Sby. Magnesian limestone, Brit., has a similar plate. Hippomya. Salter. Shell gibbous, with anterior inflated close beaks, a long cardinal edge; anterior edge short, rounded, and separated by a strong sinus from the inflated posterior ridge and slope. Fossil, 1 species. Devonian. DREISSENA, Van Beneden. Etymology, dedicated to Dreyssen, a Belgian physician. Synonyms, Mytilomya, Cantr. Congeria, Partsch. Ticho- gonia, Rossm. Type, D. polymorpha, Pl. XVII., Fig. 9. (Mytilus Volga, Chemn.) Shell like Mytilus, without its pearly lining; inner layer com- posed of large prismatic shells; um- bones terminal; valves obtusely keeled ; right valve with a slight byssal sinus ; anterior adductor supported on a shelf within the beak ; pedal impression single, * posterior. Animal with the mantle closed ; byssal orifice small; and siphon very small, coni- cal, plain, branchial prominent, fringed Fig. 218. Dreissena. inside; palpi small, triangular; foot-muscles short and thick, close in front of the posterior adductor. D. polymorpha is a native of the Aralo-Caspian rivers; in 1824 it was observed by Mr. J. Sowerby in the Surrey docks, * Hall and Salter employ the name Orthonotus for such shells as Solen constrictus. Sandb. Devonian, Germany ; Sanguinolites anguliferus, M’Coy, U. Silurian, Kendal ; an Solenopsis minor, M’Coy, Carb. limestone, Ireland. M. D’Orbigny has mistaken the plaits for teeth, and placed the genus with Mucula. The recent M. plicata, Lam., fzom Nicobar Islands, has the same long, straight back and plaited dorsal region. 424 MANUAL OF THE MOLLUSCA. to which it appears to haye been brought with foreign timber, in the holds of vessels. It has since spread into the canals, docks, and rivers of many parts of England, France, and Belgium, and has been noticed in the iron water-pipes of London, incrusted with a ferruginous deposit. (Cunnington.) Distribution, 15 species. Europe, America, Africa. Fossil, 13 species. Hocene—. Britain, Germany. Faminty ITV.—ARCADA. Shell regular, equivalye, with strong epidermis; hinge with a long row of similar, comb-like teeth; pallial line distinct ; muscular impressions subequal. Structure corrugated, with vertical tubuli in rays between the ribs or strize. (Carpenter.) Animal with the mantle open; foot large, bent, and deeply grooved; gills very oblique, united posteriorly to a membranous septum. ARCA, L. Etymology, arca, a chest. Type, A. Now, Pl. XVII., Fig. 12. Synonyms, Barbatia, Gray; Anomalocardia, Klein; Scapharca, Gray; Scaphula, Benson. Examples, A. granosa, Pl. XVII., Fig.10. A. pexata, Fig. 11. A. zebra, Fig. 13. Shell equivalve or nearly so, thick, sub-quadrate, ventricose, strongly ribbed or cancellated; margins smooth or dentated, close or sinuated ventrally; hinge straight, teeth very numerous, transverse; umbones anterior, separated by a flat, iozenge- shaped ligamental area, with numerous cartilage-grooves; pallial line simple; posterior adductor impression double; pedal scars 2, the posterior elongated. Animal with a long pointed foot, heeled, and deeply groved ; mantle furnished with ocelli; palpi0; gills long, narrow, less striated externally, continuous with the lips; hearts two, each with an auricle. The name Bysso-arca was chosen unfortunately by Swainson, for the typical species of the genus, in which the byssal orifice is sometimes very large (Pl. XVII., Fig. 13). The byssus is a horny cone, composed of numerous thin plates, occasionally becoming solid and calcareous; it can be cast off and re-formed with great rapidity. (Forbes.) The Arcas with close valves have the left valve a little larger than the right, and more ornate. The Bysso-arks secrete themselyes under stones at low water, —— |, ee eo CONCHIFERA. 425 in crevices of rocks, and the empty burrows of boring mollusks ; they are often much worn and distorted. The genus Palaarca probably belongs here; we have not been able to ascertain the generic characters ; but they may be found in the Memoirs of the Geol. Sury., Canada, Vol. III., under the head Cyrtodonta. Distribution, 140 species. World wide, most abundant in warm seas; low water—230 fathoms (A. imbricata, Poli). Prince- Regent Inlet (4. glacialis). .A scaphula, Benson, is found in the Ganges and its branches, from Calcutta to Humeerpoor on the Jumna, 1,000 miles from the sea. A second species has been found in the river Tenasserim, Birmah. The hinge is edentulous in the centre, and the posterior teeth are laminar and branched; the elements of the posterior muscular impres- sion are distinct. Fossil, 400 species. Lower Silurian—. United States, Europe, South India. CucuULL@A, Lamarck. Etymology, cucullus, a cowl. Type, C. concamerata, Pl. XVII., Fig. 14. Shell sub-quadrate, ventricose ; valves close, striated ; hinge- teeth few and oblique, parallel with the hinge-line at each end ; posterior muscular impression bounded by an elevated ridge. Distribution, 2 species. Mauritius, Nicobar, China. Fossil, 240 species. Lower Silurian. North America, Pata- gonia, Europe. Sub-genus, Macrodon, ages M..Hirsonensis, Pl. XVII., Fig. 15. Shell with a few oblique anterior teeth and one or more long laminar posterior teeth. The Ark-shells of the Palzeozoic and secondary strata have their anterior teeth more or less oblique, like Arca, the posterior teeth parallel with the hinge-line like Cucullea ; their valves are close or gaping below ; their umbones frequently sub-spiral; and the hinge-area is often very narrow, and in some species only the posterior moiety is visible. Parallelopipedum, Klein. The outermost hinge-teeth short, and perpendicular to the hinge-line; teeth developed along the whole length of the hinge. PECTUNCULUS, Lam. Type, P. pectiniformis, Pl. XVII., Fig. 16. (Arca pectun- culus, L.) Shellorbicular, nearly equilateral, smooth or radiately striated ; umbones central, divided by a striated ligamental area; hinge 426 MANUAL OF THE MOLLUSCA. with a semicircular row of transverse teeth; adductors sub- equal; pallial line simple; margins crenated inside. Animal with a large crescent-shaped foot, margins of the sole undulated; mantle open, margins simple, with minute — ocelli; gills equal, lips continuous with the gills. Distribution, 58 species. West Indies, Britain, India, New Zealand, West America; ranging from 8 to 60, rarely 120 fathoms. Fossil, 80 species. Neocomian—. United States, Europe South India. The teeth of Pectunculus and Arca increase in number with age, by additions to each end of the hinge-line, but sometimes the central teeth are obliterated by encroachments of the liga- ment. “) ' Limopsis, Sassi, 1827. Type, Li. aurita, Pl. XVII., Fig. 17. Synonym, Trigonoceelia, Nyst. Pectunculina, D’Orb. Shell orbicular, convex, slightly oblique; ligamental area with a triangular cartilage-pit in the centre; hinge with 2 equal, curved series of transverse teeth. Distribution, 4 species. Red Sea (Nyst.), Japan, Britain. Mr. M‘Andrew has dredged LZ. pygmea, living, on the coast of Finmark; it isa fossil of the Pliocene of England, Belgium, ~ and Sicily. Fessil, 36 species. Bath-oolite—. United States Europe. Nucuna, Lam. Etymology, diminutive of nux, a nut. Example, N. Cobboldiz, Pl. XVII., Fig. 18 Shell trigonal, with the umbones turned towards the short posterior side ; smooth or sculptured, epidermis olive, interior — pearly, margins crenulated; hinge with prominent internal _ cartilage-pit, and a series of sharp teeth on each side; pallial line simple. } Animal with the mantle open, its margins plain; foot large, — deeply fissured in front, forming when expanded a disk with. serrated margins; mouth and lips minute, palpi very large, rounded, strongly plaited inside and furnished with a long con- voluted appendage; gills small, plume-like, united behind the foot to the branchial septum. The Nucula uses its foot for burrowing, and Professor Forbes has seen it creep up the side of a glass of sea-water. The labial appendages protrude from the shell at the same time with the 1? Miewityo thes Weal. CONUHIFERA 427 foot. N. mirabilis, Adams, from Japan, is sculptured like the extinct N. Cobboldie. | Distribution, 70 species. United States, Norway, Cape, Japan, Sitka, Chili. On coarse bottoms, from 5—100 fathoms. Fossil, 177 species. Lower Silurian?—. Trias—. America, Europe, India. Sub-genera. Nuculina, D’Orb.* 1847. N. miliaris, Pl. XVIL., Fig. 19. Shell minute; teeth few, in one series, with a posterior lateral tooth. ocene, France. Nucinella (ovalis), Searles- Wood, 1850 (= Pleurodon, Wood, 1840), a minute shell from the Coralline crag of Suffolk, is described as haying an external ligament. ? Stalagmium (margaritaceum), Conrad, 1833=Myoparo cos- tatus, Lea. ocene, Alabama. ? S.Nystii, Galeotti (Nucunella, D’Orb.). ocene, Belgium. Shell like Limopsis; ligamental area narrow, wholly posterior. TsoaArca, Minster, 1842. Type, I. subspirata, M. Oxford Clay, France, Germany. Synonym, Noetia, Gray. Shell ventricose; beaks large, anterior, often sub-spiral; ligament entirely external; hinge-line curved, with two series of transverse teeth, smallest in the centre; pallial line simple. I. Logani (Ctenodonta), Salter, Lower Silurian, Canada, is 3 inches long, and has the ligament preserved. Fossii, 14 species. Lower Silurian—Chalk. North America. Europe. Sub-genera, Cucullella, M‘Coy. CO. antiqua, Sby. Upper Silurian, Herefordshire. Shel/ elliptical, with a strong rib behind the anterior adductor impression. Iunularca, Gray. Part anterior to the umbo toothless, with a lunule. LEDA, Schumacher. Etymology, Leda, in Greek mythology, mother of Castor and Pollux. Synonym, Lembulus (Leach) Risso. Example, Li. caudata, Pl. XVII., Fig. 20. Shell resembling Nucula ; oblong, rounded in front, produced and pointed behind; margins even; pallial line with a snall sinus; umbonal area with a linear impression joining the ante- rior adductor. Animal furnished with two partially-united, slender, unequ il, * N. donaciformis, Parreyss, from the White Nile, is a crustacean! ‘Estheria.) 428 MANUAL OF THE MOLLUSCA. siphonal tubes (Forbes); gills narrow, plume-like, deeply laminated, attached throughout; mantle-margin with small ventral lobes forming by their apposition a third siphon. Distribution, 80 species. Northern and’Arctic Seas, 10— 180 fathoms. Siberia, Melville Island, Massachusetts, Britain, Mediterranean, Cape, Japan, Australia. Fossil, 190 species. United States, Europe, South India. Sub-genus, Yoldia, Moller (dedicated to the Countess Yoldi). Fig. 219, Yoldia n. sp. ?. Antarctic Expedition. (From a drawing by Albany Hancock, Esq.) The internal organs are represented, as seen through the mantle, on the removal of the right valve. a, a, adductors ; p, p, pedal muscles; /, ligament; g, gills; s, siphons (much con- tracted); t, c, labial palpi and appendages ; 7, intestine ; f, foot ; z, z, lateral muscles of the foot ; m, pallial line. Y.myalis, Pl. XVII., Fig. 21. Shell oblong, shghtly attenuated behind, compressed, smooth or obliquely sculptured, with dark olive shining epidermis; external ligament slight; cartilage as in Leda ; pallial sinus deep. Animal with the branchial and anal siphons united, retractile; palpi very large, appendiculate ; gills narrow, posterior; foot slightly heeled, deeply grooved, its margins crenulated; intestine lying partly close to the right side of the body, and producing an impression in the shell ; mantle-margim plain in front, fringed behind; destitute of ventral lobes. Distribution, Arctic and Antarctic Seas, Green- land, Massachusetts, Brazil, Norway, Kamtschatka. Yoldia limatula (Fig. 220) has been dredged, alive, by Mr. M‘Andrew, on the coast of Finmark. Itis also found in Portland Harbour, Massachusetts. The animal is very active, and leaps to an astonishing height, exceeding in this faculty the scollop-shells. = a f CONCHIFERA. 429 (Dr. Mighels.) Fossil, Phocene—. (Crag and Glacial deposits. ) England, Belgium. Fig. 220. Yoldia limatula (after Barrett). SOLENELLA, Sowerby. Type, 8. Norrisii, Pl. XVII., Fig. 22. 8. ornata, Fig. 23. Synonyms, Malletia, Desm. Ctenoconcha, Gray. Neilo, Adams. Sheil oval, or ark-shaped, compressed, smooth or concentri- cally furrowed, epidermis olive; ligament external, elongated, prominent: hinge with an anterior and posterior series of fine sharp teeth; interior sub-nacreous; pallial sinus large and deep; anterior adductor giving off a long oblique pedal line. Animal like Yoldia; mantle-margins slightly fringed and furnished with ventral lobes; siphonal tubes united, long, and slender, completely retractile ; palpi appendiculated, convoluted, as long as the shell; gills narrow, posterior ; foot deeply cleft; forming an oyal disk, eyen-margined and striated across. Distribution, 2 species. Valparaiso, New Zealand (shell lke S. ornata). Fossil, 1 species. Miocene. Point Desire, Patagonia. ? SotEMYA, Lamarck. Type, S. togata, Pl. XXIT., Fig. 17. Synonym, Solenomya, Menke. Shell elongated, cylindrical, gaping at each end; epidermis dark, horny, extending beyond the margins; umbones poste- rior; hinge edentulous; ligament concealed; pallial line obscure. Outer layer of long prismatic cells, nearly parallel with the surface, and mingled with dark cells, as in Pinna ; inner layer also cellular. Animal with the mantle lobes united behind, with a single siphonal orifice, hour-glass shape, and cirrated ; foot probos- cidiform, truncated and fringed at the end; gills forming a single plume on each side, with the laminz free to the base ; palpi long and narrow, nearly free. + 430 MANUAL OF THE MOLLUSCA. The shell resembles Glycimeris in the shortness of its posterior — side, and the extraordinary development of its epidermis; the animal most resembles Leda in the structure of its foot and - ills. e Distribution, 4 species. United States, Canaries, West Africa — (Gaboon River), Mediterranean, Australia, New Zealand. Burrowing in mud; 2 fathoms. Fossil, 4 species. Carb. —. Britain, Belgium. FAMILY V.—TIRIGONIADA. Shell equivalve, close, trigonal, with the umbones directed posteriorly ; ligament external; interior nacreous; hinge-teeth few, diverging; pallial line simple. Animal with the mantle open; foot long and bent; gills two on each side, recumbent; palpi simple. TRIGONIA, Bruguiere (not Aublet). Etymology, Trigonos, three-angled. Synonym, Lyriodon, G. Sowerby. Example, T. Costata, Pl. XVII., Fig. 24. TT. pectinata, Fig. 221. Shell thick, tuberculated, or ornamented with radiating or Baa ft concentric ribs; posterior side Eee angular; ligament small and prominent; hinge-teeth 2.3, diverging, transversely stri- ated ; centre tooth of left valve divided; pedal impressions in front of the posterior adductor, and one in the umbo of the left valve; anterior adductor Wp IMpression close to the umbo. ! esi Animal with a long and Fig. 221. Trigonia pectinata.* pointed foot, bent sharply, heel prominent, sole bordered by two crenulated ridges; palpi small and pointed; gills ample, the outer smallest, united behind the body to each other and to the mantle. The shell of 7’rigonia is almost entirely nacreous, and usually wanting or metamorphic in limestone strata; casts of the in- — * Fig. 221. From a specimen in alcohol; the gills slightly curled and contracted, they should terminate near the margin, between the arrows which indicate the inhalent and exhalent currents: a, a', adductors ; A/, ligament ; ¢, ¢’, dental sockets ; 0, mouth, it, labial tentacles or palpi; p, pallial line; m,margin; 7, foot; v, cloaca. CONCHIFERA. 431 terior are called ‘‘ horse-heads” by the Portland quarry-men ;* they spoil the stone. Silicified casts have been found at Tisbury, in which the animal itself, with its gills, was preserved.; The species with the posterior angle of the shell elongated, have a siphonal ridge inside. The epidermal layer of the recent shell consists of nucleated cells, forming a beautiful microscopic object. A Trigonia placed by Mr. 8. Stutchbury on the gunwale of his boat leapt overboard, clearing a ledge of four inches; they are supposed to be migratory, as dredging for them is very uncertain, though they abound in some parts of Sydney Harbour. Distribution, 3 species (or varieties ?), Australia. Fossil, 100 species. Trias — Chalk (not known in Ter- _tiaries). Europe, United States, Chili, Algeria, Cape, South India. Myornortia, Bronn, 1830. Type, M. vulgaris, Schl. Synonym, Cryptina (Kefersteinu), Boue. Shell trigonal, umbones turned forwards ; obliquely keeled ; smooth or sculptured; teeth 2.3, striated obscurely, centre tooth of left valve simple, anterior of right valve prominent; mould lke Trigonia. M. decussata, Pl. XVII., Fig. 25, has a lateral tooth at the dorsal angle of the left valve. Fossil, 16 species. Trias: Germany, Tyrol. AxInus, Sowerby, 1821. Type, A. obscurus, Sowerby. Synonym, Schizodus, King (not Waterhouse). Shell trigonal, rounded in front, attenuated behind; rather thin, smooth, with an obscure oblique ridge ; ligament external ; hinge-teeth 2.3, smooth, rather small; anterior adductor slightly impressed, removed from the hinge, with a pedal scar close to it; pallial line simple. Fossil, 20 species. Upper Silurian — Muschelkalk. United States, Hurope. Mactra trigonia, Goldf. Isocardia axiniformis. Ph. Anatina attenuata and Dolabra securiformis, M‘Coy, pro- bably belong to this genus. Dolabra equilateralis, Amphidesma subtruncatum, with many others from the Palzeozoic rocks, may constitute a distinct genus, but their generic character has yet to be discovered. CuRTONOTUS. Salter. Thickened hinge-plate, with a single strong triangular central * See Plott’s Oxfordshire, T. vii. Fig. 1. t In the collection of the late Miss Benett of Warminster, now ir Philadelphia. xn 432 MANUAL OF THE MOLLUSCA, tooth on each valve. Right valve plate with an obscure tooth behind the central one. Anterior muscular scar deep; pallial impression entire. Fossil, 6 species. Devonian, Britain. PSEUDAXINUS, Salter. Type, P. (Anodontopsis) securiformis, M‘Coy, and P. trigonus. Shell thin, edentulous, convex with prominent umbones, and a strong posterior carinated edge; beaks anterior; no lunette. LYRODESMA, Conrad, 1841. Type, Li. plana, New York. Synonym, Actinodonta, Phil. Shell trigonia-shaped, rather elongated, with a striated pos- terior area; hinge -with several (5—9) radiating teeth, striated across ; hgament external. Fossil, 4 species. Lower Silurian: Canada, United States, Britain. FAMILY VI.—UNIoNIDa. Naides. Shell usually regular, equivalve, closed; structure nacreous, with avery thin prismatic-cellular tayer beneath the epidermis ; epidermis thick and dark; ligament external, large and pro- minent ; margins even; anterior hinge-teeth thick and striated, posterior laminar, sometimes wanting; adductor scars deeply impressed ; pedal scars three, distinct, two behind the anterior adductor, one in front of the posterior. ; Animal with the mantle-margins united between the siphonal orifices, and, rarely, in front of the branchial opening’; anal orifice plain, branchial fringed; foot very large, tongue-shaped, compressed, byssiferous in the fry; gills elongated, sub-equal, united posteriorly to each other and to the mantle, but not to the body; palpi moderate, laterally attached, striated inside; lips plain. Sexes distinct. The river musselsare found in the pondsand streams of all parts of the world. In Europe the species are few, though specimens are abundant; in North America both species and individuals _ abound. All the remarkable generic forms are peculiar to — South America and Africa. Two of these are fixed, and irre- © gular when adult, and have been placed with the chamas and oysters by the admirers of artificial systems; fortunately, how- ever, M. D’Orbigny has ascertained that the Mulleria, which | CONCHIFERA. 43£ is fixed and mono-myary when adult, is locomotive and di-myary when young! * Like other fresh-water shells, the naids are often extensively eroded by the carbonic acid dissolved in the water they inhabit (p. 31).+ This condition of the umbones is conspicuous in the great fossil Uniones of the Wealden, but cannot be detected in the Cardinic,and some other fossils formerly referred to this family. The outer gills of the female unionide are filled with spawn in the winter and early spring; the fry spins a delicate, ravelled byssus, and flaps its triangular valves with the posterior shell- muscle, which is largely developed, whilst the other is yet inconspicuous. The shells of the female river-mussels are rather shorter and more yventricose than the others. Unto, Retz. River-mussel. Etymology, unio, a pearl (Pliny). Example, U. litoralis, Pl. XVIII., Fig. 1. Shell oval or elongated, smooth, corrugated, or spiny, becom- ing very solid with age; anterior teeth 1.2, or 2.2, short, irre- gular; posterior teeth 1.2, elongated, laminar. Animal with the mantle-margins only united between the siphonal openings; palpi long, pointed, laterally attached. (Fig. 209, p. 399.) U. plicatus (Symphynota, Sw. Dipsas, Leach) has the valves produced into a thin, elastic dorsal wing, as in Hyria.t In the Pearl-mussel, U. Margaritiferus (Margaritana, Schum. Alasmodon, Say, Baphia, Meusch.), the posterior teeth become obsolete with age. This species, which afforded the once famous British pearls, is found in the mountain streams of Britain, Lapland, and Canada: it is used for bait in the Aberdeen Cod- fishery. The Scotch pearl-fishery continued till the end of the last century, especially in the river Tay, where the mussels were collected by the peasantry before harvest time. The pearls * In the synopsis at p. 406, it will be seen that each of the principal groups of bi- valves contains members which are fixed and irregular, and others which are byssi- ferous, or burrowing, or locomotive. } Probably many of the organic acids, produced by the decay of vegetable matter, assist in the process. It has been suggested that sulphuric acid may sometimes be set free in river-water, by the decomposition of iron pyrites in the banks; but Prof. Boye of Philadelphia, states that it has not been detected in any river of the United States where the phenomenon of erosion is most notorious. } This is the species in which the Chinese produce artificial pearls by the introduc. tion of shot, &c., between the mantle of the animal and its shell (p. 38); Mr. Gask in Las an example containing two strings of pearls, and another in the Brit. Mus. has a number of little josses made of bell-metal, now completely coated with pearl, in its interior. Uv ’ 434 MANUAL OF THE MOLLUSCA. were usually found in old and deformed specimens; round vearls about tho size of a pea, perfect in every respect, were worth £3 or £4. (Dr. Knapp.) Anaccount cf the Irish pearl- ‘ishery was given by Sir R. Redding, in the Phil. Trans., 1693. The mussels were found set up in the sand of the river-beds with their open side turned from the torrent ; about one ina hundred might contain a pearl, and one pearl in a hundred might be tolerably clear. (See p. 30). Distribution, 420 species. North America, South America, Europe, Africa, Asia, Australia. Fossil, 50 species. Wealden —. Europe, India. Sub-genera, Monocondylea, D’Orbigny. M. Paraguayana, Pee Vilt., Mis. 2. Shell with « single large, round, obtuse cardinal tooth in each valve; no lateral teeth. Distribution, 6 species. South America. Hyria, Lam. H. syrmatophora, Pl. X VIII., Fig. 3. Synonyme, Pachyodon and Prisodon, Schum. Shel/ Arca-shaped, hinge-line straight, with a dorsal wing on the posterior side; teeth elon- gated, transversely striated. Distribution, 4 species. S. America. CASTALIA, Lamarck. Type, C. ambigua, Pl. XVIII., Fig. 4. Synonym, Tetraplodon, Spix. Shell ventricose; trigonal; umbones prominent, furrowed; hinge-teeth striated; anterior 2.1, short; posterior 1.2, elon- gated. Animal with mantle-lobes united behind, forming two distinct siphonal orifices, the branchial cirrated. ’ Distribution, 3 species. Rivers of South America, Guiana, Brazil. ANODON, Cuvier. Swan-mussel. Type, A. cygneus, Fig.:208, p. 398. Etymology, anodontos, edentulous. Shell like wnio, but edentulous; oval, smooth, rather thin, compressed when young, becoming ventricose with age. Animal like unio: the outer gills of a female have been com-— puted to contain 300,000 young shells. (Lea.) See p. 14. Distribution, 100 species. North America, Europe, Siberia. Fossil, 8 species. ocene—. Europe. M. D’Orbigny relates that he found great quantities of small Anodons (Bysso-anodonta Paraniensis, D’Orbigny) 4 lines in length, attached by a byssus, in the River Parana, above Corrientes. CONCHIFERA. 435 TripinA, Lamarck. Synonyms, Mutela, Scop. Spatha, Lea (including Mycetopus). Leila, Gray. Type, 1. exotica, Pl. XVIIL, Fig. 5. Etymology, iris, the rainbow. Shell oblong ; umsones deprossed; hinge-line long, straight, attenuated towards the umbones, crenated by numerous unequal teeth ; Lhgament long and nerrow. Animal with mantle-lovez united posteriorly, forming two short siphons; mouth and lips small; palpi immense, oval ; gills united to the body. Iridina ovaia (Pleiodoz, Conrad) has a broader hinge-line. Distribution, 9 species. Rivers of Africa, Nile, Senegal. Mycrrorvs, D’Orbigny. Etymology, mukes, a mushroom, pous, the foot. Type, M. soleniformis, Pl. XVIII., Fig. 6. Shell elongated, sub-cylindrical, gaping in front; margins sub-parallel, hinge edentulous. Animal with an elongated, cylindrical foot, expanded into a disk at the end ; mantle open; gills equal; palpi short. Distribution, 3 species. River Parana, Corrientes; River Amazon, Bolivia. AQTHERIA, Lamarck. Type, Ai. semilunata, Pl. XVIII., Fig. 7. (Aitherios, aérial.) Shell irregular, inequivalye; attached by the umbo, and tubular processes of one of the valves, usually the left ; epidermis thick, olive; interior pearly, blistered (as if with air-bubbles) ; hinge edentulous; ligament external, with a conspicuous area and groove in the fixed valve; two adductor impressions, the anterior very long and irregular; pallial line simple. Animal with the mantle-lobes open; body large, oblong, pro- jecting backwards; no trace of a foot; palpi large, semi-oval ; gills sub-equal, plaited, united posteriorly, and to the body and mantle. Distribution, 4 species. River Nile, from first cataracts to Fazool;* Bivyer Senegal. MULLERIA, Férussac. Dedicated to Otto Frid. Miller, author of the ‘‘ Zoologia Danica.” Type, M. lobata, Fér., Fig. 222. Synonym, Acosteea (Guaduasana), D’Orbigny. * The “ fresh-water oysters” discovered by Bruce. U 2 M 43¢ MANUAL OF THE MOTLUSCA. Shell when young free, equivalye, Anodon-shaped, with a long aud prominent ligament, and two adductor impressions; adult irregular, inequivalye, attached by the right yalve; umbones elongated, progressively filled up with shell, and forming an irregular ‘‘ talon’ in front of the fixed valve; epidermis thick; ligamont in a marginal groove; interior pearly, muscular Fig. 222. Muilerva lobata, Fér. (Original.) impressions single, posterior. Fig. 222 represents the left, or attached valve, showing the single muscular impression, and projecting spur with the nucleus, consisting of both valves of ths fry, united, and. filled up with shell.* Distribution, River Magdalena, near Bogota, New Granada. Mr. Isaac Lea bas determined the identity of Miilleria and — Acostea by examination of Férussac’s type, and the suite of specimens, of different ages, in the collection of M. D’Orbigny.t SzcTIon B.—SIPHONIDA. Animal with respiratory siphons; mantle-lobes more or less ynited. a. Siphons short, pallial line simple; Integro-pallialia. * M. D’Orbigny very liberally placed his suite of specimens of this remarkable ~ genus in the British Museum. Oct., 1854. J ! Tho onty specimen of Miulleriain England, prior to the acquisition of the D’Orbigny _ coll-ct‘on, was purchased many years ago by Mr. Thomas Norris of Bury, for £20. CONCHIFERA. 437 Faminy VII.—CHAMID. Shell inequivalve, thick, attached ; beaks sub-spiral ; hgament external; hinge-teeth 2 in one valve, 1 in the other; adductor impressions large, reticulated ; pallial Lne simple. Animal with the mantle closed; pedal and siphonal orifices small, sub-equal; foot very small; gills two on each side, very unequal, united posteriorly. CHAMA (Pliny), L. Example, C. macrophylla, Pl. XVIII., Figs. 8, 9. Synonym, Arcinella, Schum. Shell attached usually by the left umbo ; valves foliaceous, the upper smallest ; hinge-tooth of free valve thick, curved, received between two teeth, in the other; adductor impressions large, oblong, the anterior encroaching on the hinge-tooth. Animal with the mantle-margins united by a curtain, with two rows of tentacular filaments; siphonal orifices wide apart, branchial slightly prominent, fringed, anal with a simple valve ; foot bent, or heeled; liver occupying the umbo of the attached valye only ; ovary extending into both mantle-lobes, as far as Fig, 223. Right side. Fig. 224. Left side. fig. 223. Right side, with the umbonal portion of the mantle removed. Fig. 224, Left side, showing the relative extent of the liver and ovarium. a,a, adductors; m, pallial line; e, excurrent orifice; 5b, branchial; f, foot and pedal orifice; p, posterior pedal muscle; ¢, palpi; g, gills (cantracted) ; 2, liver; a, ovarium ; d, dental lobes. the pallial line ; lipssimple, palpi small and curled ; gills deeply plaited, the outer pair much shorter and very narrow, furnished with a free dorsal border, and united behind to each other, and to the mantle ; adductors each composed of two elements. 438 MANUAL OF THE MOLLUSCA. The shell of Chama consists of three layers; the ezterral, coloured layer is laminated by oblique lines of growth, with car~ rugations at right angles to the lamina; the foliaceous spines contain reticulated tubuli; the middle layer is opaque white, and consists of ill-defined vertical prisms or corrugated struc- ture; the inner layer, which is translucent and membranous, is penetrated by scattered vertical tubuli; the minute processes that occupy the tubuli give to the mantle (and to the casts of the shell) a granular appearance (Fig. 224, 1, m). Some Chamas are attached indifferently by either valve; when fixed by the right valve the dentition is reversed, the left valve having the single tooth. Chama arcinella, which is always attached by the right umbo, has the normal dentition 1: 2; it is nearly regular and equivalve, and has a distinct lunule. Distribution, 50 species. ‘Tropical seas, especially amongst coral reefs ;—50 fathoms. West Indies, Canaries, Mediterranean, India, China. Fossil, 40 species. Green-sand—. United States, Europe. Sub-genus? Monopleura; Matheron (= Dipilidia, Math.). M. imbricata, Math. Fig. 226. Neocomian, Southern France. Fig. 225. Bi-radiolites, 3+ Fig 226. Monopleura, 4. p, point of attachment; /, ligamental groove ; a, a, corresponding areas, Shell attached by the dextral umbo; valves alike in structure and sculpturing ; fived valve straight, inversely conical, with a long, straight hgamental groove, and obscure hinge-area; oper- cular valve flat or convex, with an oblique, sub-marginal umbo. Fossil, 10 species. Neocomian—Chalk. France, Texas. They are commonly found in groups, adhering laterally, or rising one above the other; the casts of such as are known are quite simple and chama-like, CONCHIFERA. 439 DicERAS, Lamarck. Type, D. arietinum, Pl. XVIII., Figs. 10 and 11, and Figs. 227 and 228. Shell sub-equivalye, attached by either umbo; beaks very prominent, spiral, furrowed externally by ligamental grooves; hinge very thick, teeth 2.1, prominent; muscular impressions bounded by long spiral ridges, sometimes obsolete. Distribution, 5 species. Middle oolite. Germany, Switzer- land, France, Algeria. Diceras differs frora Chama in the great prominence of both its wmbones, in haying constantly two hinge-teeth in the right Fig. 227. Diceras arietinum, 3. Fig. 228. Reguienia ammonia, }. a, point of attachment ; /, 7, ligamental grooves; ¢, posterior adductor inflection. valye and one in the left, and in the prominent ridges bordering the muscular impressions. Similar ridges exist in Cucullea, Megalodon, Cardilia, and the Hippurite; they produce deep spiral furrows on the casts, which are of common occurrence in the Coral-oolite of the Alps. One or both the anterior furrows (Fig. 229, t,t) are frequently obsolete. The dental pits are much deeper than the teeth which they receive, and are sub- spiral, giving rise to bifid projections (c,c) on the casts; the single tooth in the left valve consists of two elements, and the cayity (fosset) which receives it is divided at the bottom. REQUIENIA, Matheron, Dedicated to M. Requien, author of a Catalogue of Corsican Mollusca. Example, R. Lonsdalii, Pl. XVIII., Fig. 12 and Fig. 230. R. ammonia, Fig. 189. Shell thick, very inequivalve, attached by the let umbo; liga- meut external; teeth 2:1; left valve spiral, its cavity deep, 440 MANUAL OF THE MOLLUSCa not camerated; free valve smaller, sub-spiral; posterior ad- ductor bordered by a prominent sub-spiral ridge in each valve. The shell structure of Requienia is like that of Chama. The relative size of the valves is subject to much variation ; in @. Fig. 229, Diceras, t. Fig. 230. Requienza, 4 Internal casts; a, point of attachment; c¢, c’, casts of dental pits; ¢, ¢’, furrows produced by spiral ridges. (Mus. Brit.) Fuvrt (Sharpe) they are nearly equal. The hinge-teeth are like those of Diceras ; the cavity for the posterior tooth of the right valye is very deep and sub-spiral (Fig. 230, c). The internal muscular ridges are produced by duplicatures of the shell-wall, and are indicated outside by grooves (Fig. 229, v’). In RB. sub- equalis and Toucasiana there is a second parallel ridgeyas in Hippurites and Caprotina. Fossil, 7 species. Neocomian — L. Chalk. Britain, France, Spain, Algeria, Texas. Famity VIII.—HIPPuritTipz. (Order Fiudistes, Laraarck.) Shell imequiyalve, unsymmetrical, thick, attached by the right umbo; umbones frequently camerated; structure and sculpturing of valves dissimilar; ligament internal ; hinge-teeth 1:2; adductor impressions 2, large, those of the left valye on prominent apophyses; pallial line simple, sub-marginal. The shells of this extinct family are characteristic of the cretaceous strata, and abound in many parts ofthe Peninsula, the Alps, and Hastern Europe, where the equivalent of the Lower Chalk has received the name of ‘‘ Hippurite limestone.” They occur aiso in Turkey and in Egypt, and Dr. F'. Roemer haa found them in Texas and Guadaloupe. The structure of these snelia has been fully described in the Quarterly Journal of the oe CONCHIFERA: 44} Geolcgical Socicty of London. In au the genera the shell con- sists of three layers, but the outermost, which is thin and com- pact, is often destroyed by the weathering of the specimens. The principal layer in the lower valve of the Hippurite is not really very different from the upper valve in structure; the laminz are corrugated, leaving irregular pores, or tubes, parallel with the long axis of the shell, and often visible on the rim. The umbo of the upper valve of the Radiolite is marginal in the young shell. (Q.J. Geol. Soc., vol. xi. p. 40.) They are the most problematic of all fossils; there are no recent shells which can be supposed to belong to the same family; and the condition in which ahey usually occur has in- volyed them in greater obscurity.* The characters which determine their position amongst the ordinary bivalves are the following :— 1. The shell is composed of three distinct layers. 2. They are essentially unsymmetrical, and right-and-left valved. 3. The sculpturing of the valves is dissimilar. 4, There is evidence of a large internal igament. 5. The hinge-teeth are developed from the free valve, 6. The muscular impressions are 2 cnly. 7. There is a distinct pallial line. The outer layer of shell in the Radiolite consists of prismatic cellular structure (Fig. 232); the prisms are perpendicular to the shell-laminz, and often minutely subdivided. The cells appear to haye been empty, like those of Ostrea (p.407).t Tae inner layer, which forms the hinge and lines the umbones is sub-nacreous, and very rarely preserved. It is usually replaced by calcareous spar (Fig. 239), sometimes by mud or chalk, and yery often it is only indicated by a vacuity between the outer shell and the internal mould (Fig. 244). The inner shell-layer * 1. Buch regarded them as Corals. 1840, Leonh. and Broan vahrb. p. 575. 2. Desmoulins, as a combination of the Tunicary and Sessile Cirr:pede. 3. Dr. Carpenter, as a “ group intermediate between the Conchifera aud Cirripeda.” An. Nat. Hist. XII. 390. . Prof. Steenstrup, of Copenhagen, as Annelids, . Mr. D. Sharpe refers Hippurites to the Balani; Caprinella to the Chamacezx. . La Peyrouse considered the Hippurites Orthocerata; the Ra/liclites, Ustracea. . Goldfuss and D’Orbigny place them both with the Brachiwpoda, . Lamarck and Rang, between the Brachiopoda and Ostracee. . Cuvier and Owen, with the Lamellibranchiate bivalves. 10. Deshayes, in the same group with .theria. 11. Quenstedt, between the Chamacee and Cardiacee. ¢ This is very conspicuous in Radiolites from the chalk ; a formation in which other prismatic-cellular fossils are solid. 3 U OO OND OF Pp 442 MANUAL OF THE MOLLUSCA. is seldom compact, its lamellze are extremely thin, and separatod by intervals like the water-chambers of Spondylus; similar spaces occur in the deposit, filling the umbonal cavity of the long-beaked oysters. * The inner layer ceases at the pallial line, beyond which, on the rim of the shell, the cellular structure is often apparent ; Fig. 231. Section of a fragment of Ostrea Cornucopie. obscure bifurcating impressions radiate from the pallial line to the outer margin (Fig. 232, v, v). These haye been compared to the vascular impressions of Oe 0 ae, ‘eS 99% ats cele ae TW Sais : ire 0ne, nen) ae Crania (Figs. 193, 194), and constitute the only argument for supposing the Rudistes to have been palliobranchiate ; but they * The water-chambers in some of the cylindrical Hippurites are large and regular, like those of the fossil corals Amplerus and Cyathophyllum. A section of Hippurites gi-oculatus passing through only one of the dental sockets. resembles an Orthoceras with a lateral siphuncle; whilst a Caprinella (Fig. 246), which has lost its outer layer, mic ht be mistaken for an Ammonite. + Traced from the original specimen in the Museum of the School of Mines. 3, ia the inner edge ; a, the outer edge; v, v, the dichotomons impressions; the horizontal laminee are seen on the shaded side, Lower chalk; Sussex. CONCHIFERA. 443 occur on the rim of the shell, and not on the disk, as in Craniu.* The chief peculiarity of the Hippuritide is the dissimilarity in the structure of the valves, but even this is deprived of much significance by its inconstancy.t The free valve of Hippurites is perforated by radiating canals which open round its inner margin, and communicate with the upper surface by numerous pores, as it to supply the interior with filtered water ; possibly they were closed by the epidermis. { In the closely allied genus Radiolites there is no trace of such canals, nor in Caprotina. Those which exist in the upper valve of Caprina, and in both valves of Caprinella, have no commu- nication with the outer surface of the shell; they appear to be only of the same character with the tubular ribs of Cardium costatum (Pl. XIX., Fig. 1), and it is highly improbable that they were permanently occupied by processes from the margin of the mantle. The teeth of the left, or upper valve, are so prominent and straight, that its movement must have been nearly vertical, for which purpose the internal hgament appears to have been exactly suited by its position and magnitude , but it is probable that, like other bivalves, they opened to a very small extent. HIPPURITES, Lamarck. Name, adopted from old writers, ‘‘ fossil Hippuris,”’ or Horse-tail. Types, H. bi-oculatus, Lamarck, and H. cornu-vaccinum, Fig. 237. Shell very imequivalve, inversely conical, or elongated and cylindrical ; fiwed valve striated or smooth, with three parallel furrows (/, m, n) on the cardinal side, indicating duplicatures of the outer shell layer; internal margin slightly plaited; pallial line continuous; umbonal cavity moderately deep, ligamental inflection (7) with a small cartilage-pit on each side (c,c); dentai sockets sub-central, divided by an obsolete tooth; anterior inuscular impression (a) elongated, double; posterior (a) * M. D’Orbigny considers they were produced by pectliar aypendages to the mantle-margin, which, in Hippurites, were prolonged into the canais of the upper vaive. } The lower valves of some Spondyli are squamous or spiny, the upper plain ; those of many cysters, Fectens, andsome Tellens are diversely sculptured ; but in no instance is the internal structure of the two valves different. The inconstancy of the sheil stfucture in the Rudistes has a parallel in Rhynchonella and Terebratula (p. 360), and ii tne condition of the hepatic organ in Tritonia and Dendronotus. 1 The valves of Crania are ; erforated by branching tubuli, but in that case they pase vertier It through every part of the shell, ar allits layers (p. 361), | 444 MANUAL OF THE MOLLUSCA. ; small, very deep, bounded by the second duplicature(m); third duplicature (7) projecting into the umbonal cavity: free valve — Fig. 933 interior ot lower valve, 3. Fiz. 234. Upper valve (restored), fHippurites radiosus, Vesm. Lower chalk, St. Mamest, Dordogne.* a, a, adductor impressions and processes; c, ¢, cartilage pits; ¢, t', teeth and dental sockets; uw, umbonal cavity; p, orifices of canals; /, ligamental inflection; m mus- cular, ” siphonal inflection. depressed. with a central umbo, and two grooves or pits cor- Fig. 205. A. Toucasianus, upper valve, 3.t Fig. 236. Lower valve, with mould, 4 d ltigameatal, m mus _uler, m siphonal infections; z, fracture, showing canals; c. cartiage; u, téft umbo; the arrows indicate the probable direction of the branchial currents, > responding to the posterior ridges in the lower valve; surface * From the original in the Brit. Mus. The inner layer of shell in this species has an isxégualy cellular structure, to which its preservation is due. t This internal mould, representing the form of the animal, was obtained by remov- ing che upper valve piecemeal with the chisel; a plaster-cast taken from it represents tae interior of the upper vaive, with the bases of the teeth and apophyses. See orig» nals in Brit. Mus, CONCHIFERA. 445 porous, the pores Leading to canals in the outer shell-layer, which open round the pallial line upon the inner margin; anterior cartilage-pit deep and conical, posterior shallow ; ambonal cavity turned to the front (w); teeth 2, straight, sub- central, the anterior largest, each supporting a crooked musculer apophysis, the first broad, the hinder prominent, tooth-like ; inflections (m, m) surrounded by deep channels. A. cornu-vaccinum attains a length of more than a foot, and is curved like a cow’s horn; the outer layer separates readily from the core, which is furrowed longitudinally. The ligamental inflection (/) is very deep and narrow, and the anterior tooth farther removed from the side than in H. bi-oculatus and radiosus (Figs. 233, 234); the posterior apophysiz (a’) does not nearly fill the corresponding cayity in the lower yaive. In H. bi-oculatus and some other species there is no ligamental ridge inside; these, when they have lost their inner layer, present a cylin- drical cavity with two parallel ridges, extending down one side. The third inflection (n) is possibly a siphonal fold, such as exists in the tube of Jeredo, and sometimes in the valves of Pholas, Clavagella, and the caudate species of T’rigonia. The development of processes from the upper valve, for the « ‘ Ss Sear N \ a. oe \ \ \ \ \\ Z \ \ \ \\G \ \ WG \ nr RY WON MAG; ij y Ne LZ s Y CA LAL 4 YypY — / Ay | EY 4% Yo \ / A F*~, 237. Longitudinal section ; upper half, 3. Fig. 238. Transverse section, +. Hippurites cornu-vaccinum, Bronn. Salzburg, i, m. n, duplicatures ; u, umbonal cavity of left valve; r, of right valve; c, ¢’, car- tuage-piis; t, t', teeth; 2, a’, muscular apophyses; d, outer shell-layer. Fig. 237 is taken in the line @ b of Fig. 238, cutting only the base of the posterior tooth (z’). Fig. 238 is from a larger specimen, at about the ievel d 6 of Fig. 237, cutting the point of the posterior apophysis (a'), and showing the peculiar shell-texture deposited by the anterior adductor (a). attachment of the adductor muscles harmonises with the other pecuLarities of the Hipp rite. The equal growth of the margirs 446 MANUAL OF THE MOLLUSCA, of the valves produces central umbones, and necessitates an internal cartilage; this again causes the removal of the teeth and adductors farther from the hinge-margin, to a position in which the muscles must have been unusually long, unless sup- ported in the manner described. Supposing the animal to have had a small foot, like Chama, the mantle-opening for that organ would have been completely obstructed by the adductor, but that the muscular support was hook-shaped (Fig. 239, a). The posterior adductor-process is similarly under-cut for the passage of the rectum, which in all bivalves emerges between the hinge Fig. 239. Huppurites cornu-vaccinum. Fig. 240, Radiolites cylindraceus, +. Longitudinal sections taken through the teeth (¢, t') and apophyses (a, a'). d outer, r inner shell-layer ; /, dental plate of lower valve; u, umbonal cavity of upoer valves ; 2, intestinal channel. Originals in Brit. Mus. and posterior adductor, winds round outside that muscis, and terminates in the line'of the exhalent current. There is a groove (sometimes an inch deep) round the second and third duplica- tures in the upper valve, which seems intended to facilitate the passage of the alimentary canal, and the flow of water from the gills into the exhalent channel. The smallness of the spaces for the branchize may have been compensated by deep plication of those organs, as in Chama and Tridacna. Fossil, 30 species. Chalk. Bohemia, Tyrol, France, Spain, Turkey, Syria, Algeria, Egypt. RADIOLITES, Lamarck, 1801. Etymology, radvus, a ray. Synonym, Spheerulites, De la Metherie, 1805. Shell inversely conical, bi-conic, or cylindrical; yalyes dis< similar in structure; internal margins smooth or finely striated, simple, continuous; ligamental inflection very narrow, dividing CONCHIFERA. 447 the deep and rugose cartilage pits: lower valve with a thick outer layer, often foliaceous; its cavity deep and straight, with two Fig. 241. Interior of lower valve. Fig. 242. Interior of upper valve. Radiolites mammillaris, Math. 4. L. Chalk. S. Mamest, Dordogne. 2, ligamental inflection; m, pallial line; ¢, c, cartilage pits; a, a, adductor impressions and processes ; ¢, teeth and'dental sockets. dental sockets and lateral muscular impressions; upper valve flat or conical, with a central umbo; outer layer thin, radiated ; Fig. 243. Side views of the upper valve of R. mammillaris; 1, ligamental inflection } t, teeth; a, a’, muscular processes. umbonal cayity inclined towards the ligament; teeth angular, striated, supporting,curved and sub-equal muscular processes. The upper valve of #. flewriausus has an oblique umbo, with a distinct ligamental groove. The’foliations of the lower valve are frequently undulated; they are sometimes as thin as paper, and several inches wide. The umbonal cavity of the lower valve is partitioned off by yery delicate funnel-shaped laminz. Specimens frequently occur in which the outer shell layer is preserved, whilst the inner is wanting, and the mould (‘‘ birostrites’’) remains loose in the centre. The interior of the outer shell layer is deeply 448 MANUAL OF TRE MOLLUSCA. ] > grooved with lines cf growth, and exhibits a distinct ligamenta] _ ridge in each valve. i In aged examples of R. calceoloides tho ligamenta! intlection — is concealed, the cartilage pits partially Slied up and smoothod, — Fig. 244. Upper view. Fig. 245. Side view. Internal mould of R. Hennghausit, Desm., 3. Chalk. u, umbo of left valve; 7, right umbo; /, ligamental groove ; ¢, c, cartilage; a, anteriog — adductor muscle ; a’, posterior. and the teeth and apophyses so firmly wedged into their re- spective cavities, as to suggest the notion that the valves had become fixed about a quarter of an inch apart, and ceased to open and close at the will of the animal. Fossil, 42 species. Neocomian—Chalk. Texas; Britain, France, Bohemia, Saxony, Portugal, Algeria, Egypt. Sub-genus 2 Bi-radiolites, D’Orbigny. RR. canaliculatus (Fig. 225, upper valve). Ligamental groove visible in one or both valves, sometimes occupying the crest of a ridge, and bordered by two similar areas (a, a). Fossil, 5 species. Chalk, France. oe CAPRINELLA, D’Orbigny. 4 Type, C. triangularis, Desm. (Fig. 246). Synonym, Caprinula (Boissii), D’Orbigny. Shell fixed by the apex of the right valve, or free; composed vf a thick layer of open tubes, with a thin compact superficial lamina; cartilage internal, contained in several deep pits; tumbones more or less camerated ; right valve conical or elon- gaved, with a ligamental furrow on its convex side, and furnished _ with one strong hinge-tooth supported by an oblique plate: left €ONCHIFERA. 44g valve oblique or spiral, with two hinge teeth, the anterior Fig. 246. Caprinella triangularis, Desm. U. Greensand, Rochelle, 2. A, portion of the left valve, after D’Orbigny,* the shell-wall is removed by weathe: ing, exposing the camerated interior. B, mould of five of the water-chambers. ©, mould of the body-chamber; u, umbo of right valve; s, of left valve; ¢, dental groove; a, surface from which the posterior lobe has been detached. From the originals in the Brit. Mus., presented by S. P. Pratt, Esq. supported by a plate which divides the umbonal cavity iength- wise. In C. triangularis the umbonal cayity of the spiral valve is SEIT RS A ¥S>e en Fig. 247. Straight valve. Fig. 248. Spiral valve. Transverse sections of C. Boissiz, L. Chalk, Lisbon (Mr. Sharpe), 1, position of ligamental inflection; t,teeth; c, cartilage pits; u, umbonai cavity, Fig. 248 is from a weathered specimen, which has lost the outer layer. Tre mbes of the shell-wall are filled with limestone contaming small shells, partitioned off at regular intervals (Fig. 246, A); the length of the water chambers is sometimes 3} inches, and of the body- * In M. D’Orbigny’s figure the smaller valve has been added from another speci- men, and is turned towards the spire of the large valve, (Pal. Franc. pl. 542, fig. 1). In Mr. Fratt’s specimens, and those collected by Mr. Sharpe in Portugal. the umbo of the smaller valve is turned away with a sigmoid flexure. (Q. J. Geol. Sux, VI. pl. 18.) 450 MANUAL OF THE MOLLUSCA. 7 chamber from 2 to 7 diameters; specimens measuring a yard — across may be seen on the cavernous shores of the islets near Rochelle.* (Pratt. ) . Fossil, 6 species. Neocomian—Lower Chalk. France, Portaeaa Texas. Fig. 249.C. Aguiillonz, left valve Fig. 250.C. adversa (after D’Orb.). a, a, position of adductors; J, ligament; wu, umbonal cavity; t, tooth of fixed valve, broken off and remaining in its socket ; ¢, original point of attachment. Caprina, C. D’Orbigny. Etymology, caprina, pertaining to a goat. Synonym, Plagioptychus, Matheron. Type, C. Aguilloni, ©. D’Orbigny. Lower Chalk, Tyrol” (= C. Partschii, Hauer). Shell with dissimilar valves, cartilage internal; fixed yalye conical, marked only by lines of growth and a ligamental groove; hinge-margin with several deep cartilage-pits ; and one large and prominent tooth on the posterior side; free valye oblique or spiral, thick, perforated by one or more rows of flattened canals, radiating from the umbo and opening around the inner margin; anterior tooth supported by a plate which divides the umbonal cavity lengthwise, posterior tooth obscure ; ; hinge-margin much thickened, grooved for the cartilage. In C. adversa (Fig. 250) the free valve is (0) sinistrally spiral ; its cavity is partitioned off by numerous septa, and divided — longitudinally by the dental plate. When young it is attached by the apex of the straight valve (c), but afterwards becomes detached, as the large specimens are found imbedded with the — spire downwards. (Saemann.) The lower valve of C. Coguandiana — is sub-spiral. * These singular fossils were called ichthyosarcolites by Desmarest, from their Fesemblance to the flaky muscles of fishes. CONCHIFERA. 451 Fossil, 10 species. Upper Greensand and Lower Chalk. Bohemia, France, Texas. Fig, 251. Internal mould of Capretsna quadripartita, D’Orb., $. u, left umbo; 7, right umbo; Z, ligamental inflection; ¢, cartilage ; t,t’, dental sockets a, a', position of adductors; at e, a portion of tr- thicd lobe is broken away.* From 4a specimen collected by Mr. Pratt. CaPRoTINA, D’Orbigny. Type, C. semistriata, Pl. XIX., Figs. 13 and 14. Le Manz, Sarthe. Shell composed of two distinct layers; valves alike in struc- ture, dissimilar in sculpturing; ligamental groove slight ; - cartilage internal ; right valve fixed, striated, or ribbed, with one PLDI OC ian. rr narrow tooth between two deep pits, cartilage pits several on each side of the ligamental inflection, posterior adductor sup- ported by a plate: free valve flat or conyex, with a marginal umbo ; teeth 2, very prominent, supported by ridges (apophyses) of the adductor muscles (aa’), the anterior tooth connected with a third plate (n), which divides the umbonal cayity. The smaller Caprotine occur in groups, attached to oyster- ‘shells; their muscular ridges are much less developed than in the large species (Fig. 251). C. costata is like a little Radiolite. Fossil, 10 species. Upper Greensand, France. (The rest are Chamas, &c.) FamILty [X.—TRIDACNIDA. Shell regular, equivalye, truncated in front; ligament external; valves strongly ribbed, margins toothed; muscular mnpressions blended, sub-central. obscure. * The first and fourth lobes, those on each side of the ligamental inflection, appear to be the two divisions of a great internal cartilage, iike thet of the Radiolite. (Figs «244, 245, c, c.) 452 MANUAL OF THE MOLLUSCA. : Avimal attached by 2 byssus, or free ; mantle-lobe extensively united; pedal opening large, anterior; siphonal orifices sur= rounded by « thickened pallial border; branchial plain; anal remote, with a tubular valve; shell-muscle single, large and round, with a smaller pedal muscle close to it behind; foot finger-like, with a byssal groove; gills 2 on each side, narrow, strongly plaited, the outer pair composed of a single lamina, the — inner thick, with margins conspicuously grooved; palpi very slender, pointed. he shell of T’ridacna is extremely hard, beimg calcified until most every trace of organic structure is obliterated. (Car- perter. ) TRIDACNA, Bruguiére. Clam-shell. Etumology, tri, three, dakno, to bite; a kind of oyster. {Pliny.) Example, T. squamosa, Pl. XVIII., Fig. 15. Shell massive, trigonal, ornamented with radiating ribs and imbricating foliations: margins deeply indented; byssal sinus Fig. 282. Tridacna Crocea, Lam. (Original.) A a, the single adductor muscle; p, pedal muscle, and pedal opening in mactle “4 f, the small grooved foot; 0, byssus: t, labial tentacles; g, gills; 2, the bread pallial muscle; between g and / is the renal organ; m, the double mantle-margin; #. the siphoral border; i, inhalent orifice; e, valvular excurrent orifice. An, Nat His 1855, p. 190. in each yalve large, close to the umbo in front; hinge tee 1.1, posterior laterals 2.1. A pair of valves of 7. gigas, weighing upwards of 500 lbs. and measuring about 2 feet across, are used as benitiers in the Church ~ CONCHIFERA. : 453 of St. Sulpice, Paris. (Dillwyn.) Captain Cook states that the animal of this species sometimes weighs 20 lbs. and is good eating. * Fig. 252 shows the animal of Tridacna, as seen on removing the left valve and part of the mantle within the pallial line. Distridution, 7 species. Indian Ocean, China Seas, Pacific. Fossil, T. media. Miocene, Poland (Pusch). Tridacna and Hippopus are found in the raised coral-reefs of Torres Straits. (Macgillivray.) Sub-genus. Hippopus, Lamarck. H. maculatus, Pl. XVIII., Fig. 16. The ‘‘bear’s-paw clam” has close valves with two hinge-teeth in each. It is found on the reefs in the Coral Sea. The animal spins a small byssus. FAMILY X.—CARDIADA. Shell regular, equivalve, free, cordate, ornamented with radiating ribs; posterior slope sculptured differently from the front and sides; cardinal teeth two, laterals 1.1 in each yalve; ligament external, short and prominent; pallial line simple or slightly situated behind; muscular impressions sub-quadrate. Animal with mantle open in front; siphons usually very short, cirrated externally ; gills two on each side, thick, united posteriorly ; palpi narrow and pointed ; foot large, sickle-shaped. Carpium, L. Cockle. Etymology, kardia, the heart. Synonym, Papyridea, Sw. Types, O. costatum, Pl. XIX., Fig. 1. C. lyratum, Fig. 2. _ Shell ventricose, close or gaping posteriorly ; umbones promi- nent, sub-central; margins crenulated; pallial line more or less sinuated. Animal with the mantle-margins plaited; siphons clothed with tentacular filaments anal orifice with a tubular valve; branchial fringed; foot long, cylindrical, sickle-shaped, heeled. The cockle (C. edule) frequents sandy bays, near low water; a small variety lives in the brackish waters of the rives: Thames, as high as Grayesend; it ranges to the Baltic, and is found in the Black Sea and Caspian. C. rusticwm extends from the Icy Sea to the Mediterranean, Black Sea, Caspian, and Aral. On the coast of Devon the large prickly cockle (C. aculeatum) is eaten. i ee * “We stayed a long time in the lagoon (of Keeling Id.), examining the fields c? sure. and the gigantic clam-shells, into which if aman were to put his hand, he would got, a5 !ong as the animal lived, be able to withdraw it.” (Darwin’s Journal, p. 460.) 7 454 MANUAL OF THE MOLLUSCA. Sub-genera. Hemicardium (Cardissa) Cuvier. C. hemcardium, Pl. XIX.. Fig. 3. Shell depressed, posterior slope flat, valves prominently keeled. Inthocardium ayiculare, Pl, XVIil., Fig. 17. Shell triangular, keeled; anterior side very short; hingu-teeth 1.2, directed backwards ; posterior laterais 2.1; anterior muscular pit minute, posterior impression large, remote from the hinge. L. cymbulare, Lam,. exhibits sight indications of a byssal sinus in the front margins of the valyes. Fossil, Eocene, France. These shells present considerable resemblance te Triducna. Serripes (groenlandicus) Beck. Hinge edentulous. Arctic Seas, from C. Parry to Sea of Kara; fossil in the Norwich Crag. Fig. 253. C. leviusculum, Eichw. (after Middendorff). Adacna, Eichwald. C. edentulum, Pl. XIX., Fig.4. (Acardo, Sw. not Brug. Pholadomya, Ag. and Mid. not Sby.) Shell coin- pressed, gaping behind, thin, nearly edentulous; pallial line sinuated. Animal with the foot (/) compressed; siphons (s) elongated, united nearly to theend, plain. Distribution, 8 species. Aral, Caspian, Azof, Black Sea, and the embouchures of the Wolga, Dniester, Dnieper, and Don; burrowing in mud. C. Caspicwum (Monodacna, Eichw.) has a single hinge-tooth, and © C. trigonoides (Didacna, EH.) rudiments of two teeth. The siphonal inflection varies in amount. Distribution, 200 species. World-wide; from the sea-shore to 140 fathoms. Gregarious on sands and sandy mud. . Fossil, 380 species. Upper Silurian —. Patagonia — Southern India. i C. Hillanwm, Sby. {Protocardium, Beyr.), is the type of a small group iu which the sides are concentrically furrowed, the posterior slope radiately striated; the palliai bne is slightly sinuated. Jura — Chalk; Europe, India. - CoNOCcARDIUM, Bronn. Synonyms, Lychas, Stein. Pleurorhynchus, Ph. Luruio- — eardium, Miinster. CONCHIFERA. 455 Type, O. Hibernicum, Pl. XIX., Fig. 5. OC. aliforme, Fig. 254. Shell, equivalve trigonal, conical and gaping in front, truncated behind, with a long siphonal tube near the umbones; anterior Fig. 254. Conocardium aliforme, Sby. Carb., Ireland. (Mus. Tennant.) slope radiately, posterior obliquely striated; margins strongly crenulated within; hinge with anterior and posterior laminar teeth; ligament external. The truncated end has usually been considered anterior, a con- clusion which seems incompatible with the vertical position and burrowing habits of most free and equivalve shells ; if compared with Adacna (Fig. 253) the large gape (a) will be for the foot, and the long tube (s) siphonal. C, Hibernicum has an expanded keel, ike Hemicardium inversum. The shell-structure is pris- matic-cellular, as first pointed out by Sowerby; but the cells are cubical, and much larger than in any of the Aviculade. In Cardium the outer layer is only corrugated or obscurely pris- matic-cellular. Fossil, 30 species. U. Silurian — Oarb. North America, Europe. FAMILY XI.—LUCINIDZE. Shell orbicular, free, closed; hinge-teeth 1 or 2, laterals 1—1 or obsolete; interior dull, obliquely furrowed; pallial line simple; muscular impressions 2, elongated, rugose; ligament inconspicuous or sub-internal. Animal with mantle-lobes open below, and having one or two siphonal orifices behind; foot elongated, cylindrical, or strap-shaped (ligulate), protruded at the base of the shell; gills one (or two) on each side, large and thick, oval; mouth and palpi usually minute. The Lucinide are distributed chiefly in the tropical and temperate seas, upon sandy and muddy bottoms, from the sea- _ shore to the greatest habitable depths. The shell consists of two distinct layers. Fig. 255 represents the animal of a species of Diplodonta, 456 ‘MANUAL OF THE MOLLUSCA. from the Philippizes, a3 seen on removing the left valve, and part of’ tne mantle within the pallial line; b-c. the large pedal opening; the arrows indicate ths small plain incurrent orifice, and the valvular excurrent orl= fice; jf, the foot, contracted in spirit; pp, the large striated palpi; 7, the liver; the outer gill has a stmple margin, the inner is grooyed and conducts to the mouth. This genus has higher claims than Kellia to be regarded as the type of a family. Fig, 255. Diplodonta. Lucina, Bruguiére. Etymology, Lucina, a name of Juno. Type. L. Peunsylvanica, Pl. XIX., Fig. 6. Shell orbicular, white; umbones depressed; lunule distinct ; margins smooth or minutely crenulated; ligament oblique, semi-internal; hinge-teeth 2.2, laterals 1—1 and 2—2, or obso- lete; muscular impressions rugose, anterior elongated within _ the pallial line, posterior oblong ; umbonal area with an oblique furrow. Animal with the mantle freely open below; siphonal orifices simple ; mouth minute, lips thin; gills single on each side, very large and thick ; foot cylindrical, pointed, slightly heeled at the base. The foot of Lucina is often twice as long as the animal, but is © usually folded back on itself and concealed between the gills ; it is hollow throughout. J. lactea (Loripes, Poli.) has a long contractile anal tube. JZ. tigrina (Codakia, Scop.) has the liga- ment concealed between the valves, its lateral teeth are obsolete. Distribution, 70 species. West Indies, Norway, Black Sea, New Zealand; 120 fathoms. . Fossil, 250 species. U. Silurian —. United States — T. del Fuego; Eurepe — Southern India. Sub-genera, @ryptolen, Turton. LL. flexuosa, Pl. XIX., Fig. 7. Synonyms, Ptychina. Phil. Thyatira, Leach. Clausina (ferruginosa) Jeffr. Shell thin, edentulous; ligament quite in- — ternal, oblique. Animal with a long anal tube. Distribution, — 5 species. Norway — New Zealand. Foss¢l, 2 species, Eocene —. — United States, Europe. | Psathura, Deshayes. Anterior adductor scar long, narro#;_ hinge-teeth 2.2; umbones imperceptible. | CONCHIFERA, 457 CorBIs, Cuvier Etymology, corbis, a basket. Type, C. elegans. Pl. XIX., Fig. 8. Synonyms, Fimbria, Muhl. not Bohadsch. ‘‘ Idotzea,” Schum. Shell oval, ventricose, sub-equilateral, concentrically sculp- tured ; margins denticulated within; hinge-teeth 2, laterals 2, in each valve ; pallial line simple ; umbonal area with an oblique furrow, muscular i impressions round and polished ; pedal scars close to adductors. Animal with the mantle open below, doubly fringed; foot long pointed; siphonal opening single, with a long retractile tubular valve; lips narrow; palpi rudimentary ; gills single on each side, thick, quadrangular, plaited, united behind. Distribution, 5 species. India, China, North Australia, Pacific. Fossil, 80 species (including sub-genera). Lias—. United States, Europe. In C. dubia (Semi-corbis) Desh., from the Zocene, Paris, the lateral teeth are obsolete. Sub-genera. Sphera (corrugata), Sby. Shell globular, con- centrically furrowed and obscurely radiated ; ligament promi- nent; margins crenulated; hinge-teeth 2.2, obscure; laterals obsolete. Fossil, Trias — Chalk. Europe. Sportella, Deshayes. Like Spheera, but with 2.1 hinge-teeth. ? Unicardium, D’Orb. (Mactromya, Ag. part.) = Corbula cardioides, ony. Shell thin, oval, ventricose, concentrically _ striated ; ligamental plates elongated ; pallial line simple ; hinge with an obscure tooth, or edentulous. Jossil, 40 species? Lias — Portlandian. Europe. ? TANCREDIA, Lycett, 1850- Dedicated to Sir Thomas Tancred, Bart., founder of the Cotteswold Naturalists’ Club. Example, T. extensa, L. Pl. XXI., Fig. 2 Synonym, Hettangia, Turquem. , Shell trigonal, smooth; anterior side usually longest; cardi- nal teeth 2.2, one of eas small; a posterior lateral tooth in each yalye; ligament external; muscular impressions oval ; pallial line simple. Fossil, 12 species. Lias — Bath Oolite. Britain, France. 458 MANUAL OF THE MOLLUSCA. DIPLODONTA, Bronn. Etymology, diplos, twin, odonta, teetn. Synonym, Spheerella, Conrad. Type, D. lupinus (Venus) Brocchi. Pl. XTX., Fig. 2. © Shell sub-orbicular, smooth; ligament double, rather long, sub-marginal; hinge-teeth 2.2, of which the anterior in the left valve, and posterior in the right, are bifid; muscular im- pressions polished, anterior elongated. Animal with the mantle-margins nearly plain, united; pedal opening large, ventral; foot pointed, hollow; palpi large, free; gills two on each side, distinct, the outer oval, inner broadest in front, united behind; branchial orifice small, simple; anal larger, with a plain valve. Distribution, 40 species. West Indies, Rio, Britain, Medi- terranean, Red Sea, West Africa, India, Corea, Australia, Cali- fornia. D. diaphana (Felania, Recluz) burrows in sand. Fossil, 30 species, Eocene —. United States, Kurope. ? Scacchia, Philippi, 1844; Tellina elliptica, Sc. Shell minute, ovate, posterior side shortest ; hinge-teeth 1 or 2, laterals obso- lete; ligament minute; cartilage internal, in an oblong pit. Animal with mantle widely open; siphonal orifice single ; foot compressed, linguiform; palpi moderate, oblong. Distribution, 2 species. Mediterranean. fossil, 1 species. Pliocene, Sicily. ? Cyamium, Philippi, 1845. O. Antarcticum, Pl. XIX., Fig. 16. Shell oblong; hinge-teeth, 2.2; ligament double; cartilage in a triangular groove behind the teeth in each valve. Distribution, 3 species. Patagonia, Northern Europe. Jossil, 1 species. Tertiary, Europe. Uneutina, Daudin. Etymology, ungulina, like a hoof. Type, U. Oblonga. Pl. XIX., Fig. 10. Shell sub-orbicular; ligament very short; epidermis thick, wrinkled, sometimes black; hinge-teeth 2.2; muscular im- pressions long, rugose. Animal with the mantle open below, fringed ; siphonal orifice single; foot vermi-form, thickened at the end and perforated, — projecting from the base of the shell or folded up between the — gills, palpi pointed; gills two on each side, unequal, the front. Distribution, 4 species. Senegal, Philippines, excavating winding galleries in coral. external narrower, with a free dorsal border, inner widest in j CONCHIFERA. 459 Keira, Turton, 1822. Etymology, named after Mr. O’Kelly, of Dublin. Synonyms, Lasea (Leach), Br. 1827. Cycladina (Adansonii) Cantr. Bornia (sub-orbicularis) Phil. Poronia (rubra), Recluz (not Willd). Hrycina (cycladiformis), Desh. (not Lam.) Types, K. sub-orbicularis, Mont. K. rubra. Pl. XIX Fig. 12. Shell small, thin, sub-orbicular, closed ; beaks small ; margins smooth; ligament internal, interrupting the margin (in K. suborbicularis), or on the thickened margins (in K. rubra); cardinal teeth 1 or 2, laterals 1—1 in each valve. Animal with the mantle prolonged in front into a respiratory canal, either complete (in K. suborbicularis) or opening into the pedal sht (in K. rubra); foot strap-shaped, grooved; gills large, two on each side, united posteriorly, the external pair narrower and prolonged dorsally ; palpi triangular; posterior siphonal orifice single, exhalent. The hinges of these little shells are subject to variations, which are not constantly associated with the modifications of the mantle-openings. They creep about freely, and fix them- selves by a byssus at pleasure. K. rubra is found in creyices of | rocks at high-water mark, and often in situations only reached by the spray,,except at spring-tides; other species range as deep as 200 fathoms. K. Laperousii (Chironia), Desh. Pl. XIX., Fig. 11, was obtained, burrowing in sandstorfe, fiom deep water, at Monterey, California. Distribution, 20 species. Norway— New Zealand— California. Fossil, 20 species. Eocene—. United States, Europe. Sub-genera. Turtonia (minuta), Hanley. Shell oblong, in- equilateral, anterior side very short; ligament concealed between the valves; hinge-teeth 2.2. Animal with the mantle open in front; foot large, heeled; siphon single, slender, elongated, protruded from the long end of the shell. Distribution, Greenland, Norway, Britain. In pools and cre- vices of rocks between tide-marks, and in the roots of sea- weeds and corallines. Mr. Thompson obtained them from the stomachs of mullets taken on the north-east coast of Ireland. Pythina (Deshayesiana), Hinds. (Myllta, D’Orb, and Recl.) Shell trigonal, divaricately sculptured ; ligament internal; right valye with 2 lateral teeth, left with 1 cardinal and 2 laterals. Distribution, 8 species, New Ireland, Australia, Philippines, Fossil, 2 species, Eocene—, France, Java. x2 460 MANUAL OF THE MOLLUSCA. Monracuta, Turton. Nedicated to Colonel George Montagu, the most distinguished of the earlier English malacologists. Type, M. substriata. Pl. XIX., Fig. 13. Shell minute, thin, oblong, anterior side longest; hinge-line notched ; ligament internal, between 2 laminar, diverging teeth (with a minute ossicle. Loyén.) Animal with the mantle open in front; margins simple; siphonal orifice single; foot large and broad, grooved. The Montacute moor themselves by a byssus, or walk freely ; M. substriata has only been found attached to the spines of the scent aati purple theart-urchin (Spatangus purpureus) in 5—90 fathoms. ~ M. bidentata burrows in the valves of dead oyster-shells. Distribution, 3 species. United States, Norway, Britain, Aigean. Fossil, 2 species. Pliocene—. Britain. L=EptTon, Turton. Etymology, lepton, a minute piece of money (from Jeptos, thin). Synonym ? Solecardia (eburnea), Conrad, Lower California. Type, Li. squamosum. Pl. XIX., Fig. 14. Fig. 256. Shell sub-orbicular, compressed, smooth, or shagreened, a little opened at the ends and longest behind; hinge-teeth 0.1 or 1.1 in front of an angular cartilage notch; lateral teeth 2.2 and 1.1. open in front, extending beyond the shell, and bearing a fringe of filaments, of which one in front (¢) is very large; siphon (s) single, gills two on each side, separate ; foot (/ ) thick, tapering, heeled and grooved, form- ing a sole or creeping disk. (Alder.) Sub-genus. Scintilla (Cumingi), Desh. 1856. Small shells resembling Lepton; minutely punctate; ligament internal, oblique; hinge-teeth 1. 2; posterior laterals 1. 2. Distribu- tion, 37 species (?), Philippines, North Australia, Panama. Distribution, 50 species. United States, Britain, Spain. Laminarian and Coralline Zones. fossil, 5 species. Pliocene—. United States, Britain. Fig. 2 256. on. Animal with the mantle (m) — CONCHIFERA. 461 GALEOMMA, Turton. Synonyms, Hiatella, Costa (not Daud.) ; Parthenopea, Scacchi (not Fabr). Type, G. Turtoni, Pl. XIX., Fig. 15. (Galee, weasel, omma, eye. Shell thin, oval, equilateral, gaping widely below; invested with a thick, fibrous epidermis; beaks minute; ligament internal; teeth 0.1. ~ Animal with the mantle-lobes united behind and pierced with one siphonal orifice, margins double, the inner with a row of eye-like tubercles; gills large, sub-equal, united behind ; lips large, palpi lanceolate, plaited; foot long, compressed, with a narrow flat sole. The Galeomma spins a byssus, but breaks from its mooring at will and creeps about like a snail, spreading out its valves nearly flat. (Clarke.) Distribution, 14 species. Britain, Mediterranean, Mauritius, Pacific. Fossil, 1 species. Pliocene—. . Sicily. FaAamIty XII.—CycLADIDA. Shell sub-orbicular, closed; ligament external; epidermis thick, horny; umbones of aged shells eroded; hinge with car- dinal and lateral teeth; pallial line simple, or with a very small inflection. Animal with mantle open in front, margins plain; siphons (1 or 2) more or less united, orifices usually plain; gills 2 on each side, large unequal, united posteriorly ; palpi lanceolate ; foot large, tongue-shaped. All the shells of this family were formerly included in the genus Cyclas, a name now retained for the small species inha- biting the rivers of the north temperate zone; the Cyrene are found in warmer regions, on the shores of creeks and in brackish water, where they are gregarious, burying vertically in the mud, and often associated with members of marine genera. Cycias, Bruguiére. Etymology, kuklas, orbicular. Type, C. Cornea. Pl. XIX., Fig. 17. Synonyms, Spheerium, Scop. Pisum, Muhlf. (not L.) Mus- sulinm, Link. 462 MANUAL OF THE MOLLUSCA. Shell thin, yentricose, nearly equilateral; cardinal teeth 2.1, minute, laterals 1—1: 2—2, elongated, compressed. a Animal oyo-viviparous; siphons partly united, anal shortest, ~ orifices plain, gills very large, the outer smallest, with a dorsal flap; palpi small and pointed. The fry of Cyclas are hatched in the internal branchiee, they are few in number and very unequal in size; a full-grown C. cornea has about 6 in each gill; the largest being ¢ to + the length of the parent. The young Cyclades and Pisidia are very active, climbing about submerged plants and often suspending themselves by byssal threads; the striated gills and pulsating heart are easily seen through the shell. Fig. 257. Pisidium amnicum, %, with its foot protruded. Sub-genera, Pisidium, Pfr. P. amnicum, Pl. XIX., Fig. 18. Shell inequilateral, anterior side longest; teeth stronger than in Cyclas. Animal with a single, small, excurrent siphon; bran- chial and pedal orifices confluent. Distribution, 60 species. United States, South America, Greenland, Norway, Sicily, Algeria, Cape, India, Caspian, Britain. Fossil, 38 species. Wealden—. Europe. CyrENA, Lamarck. Etymology, Cyrene, a nymph. Type, C. cyprinoides, Pl. XTX., Fig. 20. Shell oval, strong, covered with thick, rough epidermis; ligament thick and prominent; hinge-teeth 3.3, laterals 1—1 in each valve; pallial line slightly sinuated. Animal (of type) with the mantle open in front and below, margins plain; siphons short, orifices fringed; gills unequal, square in front, plaited, inner lamina free at base ; palpi lanceo= s late; foot strong, tongue-shaped. Sub-genera, Corbicula, Muhlf. CC. consobrina, Pl. XIX., ; Fig. 21. Shell orbicular, concentrically furrowed, epidermis polished ; lateral teeth elongated, striated across. CONCHIFERA. 463 Batissa, Gray. Anterior lateral teeth short ; under ones long, Velorita, Gray. Anterior laterals thick and triangular. Distribution, 130 species. ‘Tropical America (eastern), Egypt, India, China, Australia, Pacific Islands. In the mud of rivers, and in mangrove swamps, usually near the coast. C. consobrina ranges from Egypt to Cashmere and China, and is found fossil in the Pliocene formations of England,* Belgium, and Sicily. Fossil, 105 species. "Wealden—. Eurove, United States. ? CYRENOIDES, Joannis. Synonym, Cyrenella, Desh, Type, C. Dupontiu, Pl. XTX., Fig. 19. Shell orbicular, ventricose, thin, eroded af the beaks; epi- dermis dark olive; hgament external, prominent, elongated ; cardinal teeth 3.2, the central tooth of the right valve bifid ; muscular impressions long, narrow; pallial line simple. Animal with the mantle open in front and below, margin simple, siphons short, united; palpi moderate, narrow; gills very unequal, narrow, united behind ; foot cylindrical elongated. Distribution, 4 species. River Senegal. The marine species are Diplodonte. Fossil, 1 species. Europe. Faminty XIIT.—Cyprinipz. Shell regular, equivalve, oval or elongated; valves closes solid; epidermis thick and dark; ligament external, conspicu- ous; cardinal teeth 1—3 in each valve, and usually a posterior lateral tooth ; pedal scars close to, or confluent with, the adductors; pallial line simple. Animal with the mantle-lobes united posteriorly by a curtain, pierced with two siphonal orifices ; foot thick, tongue-shaped ; gills 2 on each side, large, unequal, united behind, forming a complete partition; palpi moderate, lanceolate. One half the genera of this family are extinct, and the raat (excepting Circe) were more abundant in former periods than at the present time. Cyprina and Astarte are boreal forms; Circe and Cardita abound in the Southern seas. CypriIna, Lamarck. Etymology, Kuprinos (from Kupris), related to Venus. Type, C. Islandica, Pl. XTX., Fig. 22. * Associated with the bones of Elephas meridionaiss, Rhinoceros leptortinus, | Mastodon Arvernensis, Hippopotamus major, Sc. 464 MANUAL OF THE MOLLUSCA. Synonym, Arctica, Schum. Shell oval, large and strong, with usually an oblique line or angle on the posterior side of each valve; epidermis thick and dark; ligament prominent, umbones oblique; no lunule; cardinal teeth 2.2, laterals 0O—1, 1—0; muscular impressions oval, polished; pallial sinus pheslets. Animal with the mantle open in front and below, margins plain; siphonal orifices close together, fringed, slightly pro- jecting; outer gills semilunar, inner truncated in front. The principal hinge-tooth in the right valve of Cyprina represents the second and third in Venus and Cytherea; the second tooth of the left valve is consequently obsolete. Distribution, C. Islandica ranges from Greenland and the United States to the Icy Sea, Norway, and England; in 5—80 fathoms water. It occurs fossil in Sicily and Piedmont, but not alive in the Mediterranean. | Fossil, 90 species. (D’Orbigny.) Muschelkalk—. Europe. — CrrcEe, Schumacher. Etymology, in Greek mythology a celebrated enchantress. Example, C. corrugata, Pl. XX., Fig. 2. Synonym, Paphia (undulata), Lamarck.* Shell sub-orbicular, compressed, thick, often sculptured with diverging strizs; umbones flat; lunule distinct; ligament — nearly concealed; margins smooth; hinge-teeth 3:3; laterals obscure; pallial line entire. Animal (of C. minima) with the mantle open, margins denti- culate, siphonal orifices close together, scarcely projecting, fringed ; foot large, heeled ; palpi long and narrow, Ranges from 8—50 fathoms. (Forbes.) Distribution, 40 species. Australia, India, Red Sea, Canaries, Britain. ASTARTE, Sowerby, 1816. Synonym, Crassina, Lamarck. Tridonta, Schum. Goodall, Turton. Example, A. sulcata, Pl. XX., Fig. 1. A. borealis, Fig. 258. (Astarte, the Syrian Venus.) Shel sub-orbicular, compressed, thick, smooth or concens * This name was employed by Bolten, in 1798, for sp. of Veneride, and ty Lamarck, in 1801, for Venus divaricata, Chemn. (= Circe divaricata and Crassatella contraria), and Mesodesma glabratum. In 1808, Fabricius adopted the name for a group of butter- flies, in which sense it is now widely employed, having been abandoned by Lamarck in his later works, and by all succeeding malacvlogists. CONCHIFERA. 465 trically furrowed ; lunule impressed; ligament external ; epi- dermis dark; hinge-teeth 2.2, the anterior tooth of the nght valve large and thick ; anterior pedal scar distinct ; pallial line simple. Animal with mantle open; margins plain or slightly fringed ; siphonal orifices simple; foot moderate, tongue-shaped ; lips large, palpi lanceolate; gills nearly equal, united behind, and attached to the siphonal band. The animal of Astarte borealis is shown in Fig. 258; mantle- margins free, plain, slightly cirrated in the branchial region; united posteriorly by the branchial septum, forming a single excurrent orifice ; pedal muscles (p p’), distinct from adductors ; gills flat, finely striated, destitute of internal partitions; outer Fig. 258. -Astarte borealis, var. semi-sulcata, Leach, $. Wellington Channel. gill narrow, elliptical, with a simple margin ; inner gill grooved, conducting to the mouth. Distribution, 20 species. Behring’s Straits, Wellington Chan- nel, Kara Sea, Ochotsk, United States, Norway, Britain, Canaries, Aigean (30—112 fathoms). Fossil, 285 species. Carb. —. North and South America Europe, Thibet. ? Digitaria, Wood; Tellina digitaria, Lower Mediterranean, Fossil, Pliocene, Britain. GouupiA, C. B. Adams. Shell minute, triangular, furrowed: hinge like Astarte, with lateral teeth; pallial line simple. Distribution, 7 species. Panama, West Indies. x3 466 MANUAL OF THE MOLLUSCA, CRASSATELLA, Lamarck. Synonyms, Ptychomya, Ag. Paphia (Lamarck, part) Rvissy. Type, C. ponderosa, Pl. XXI., Fig. 4. C. pulchra, Fig. 259 Etymology, crassus, thick. Shell solid, ventricose, attenuated behind, smooth or con- centrically furrowed; lunule distinct; ligament internal ; margin smooth or denticulated; pallial line simple; hinge- teeth 1.2, striated, in front of cartilage pit; lateral teeth 0O—1, 1—0; adductor impressions deep, rounded; pedal small, distinct. Animal with mantle-lobes united only by the branchial septum ; inhalent margins cirrated ; foot moderate, compressed, triangular grooved; gills smooth, unequal, outer semi-lunar, inner widest in front; palpi triangular. Fig. 259. Crassatella pulchra. Sandy Cape, J. B. Jukes. Animal as seen on the removal of right valve, and portion of the mantle. In Orassatella pulchra the animal is like Astarte ; foot lingui- form, slightly grooved; palpi short and. broad, few-plaited ; outer gill narrower in front. Ree, Distribution, 34 species. Australia, New Zealand, Philippines, India, West Africa, Canaries, Brazil. Fossil, 64 species. Neocomian —. Patagonia, United States, Europe. TsocARDIA, Lamarck. Heart-cockle. Etymology, isos, like, cardia, the heart, Type, I. cor. Pl XX., Fig. 3. CONCHIFERA. 467 Synonyms, Glossus, Poli; Bucardium, Muhlfeldt; Pecchiol.a, Meneghini. Shell cordate, yventricose; umbones distant, sub-spiral; ligament external; hinge-teeth 2.2 ; laterals 1—1 in each valve, the anterior sometimes obsolete. Animal with the mantle open in front; foot triangular, pointed, compressed; siphonal orifices close together, fringed ; palpi long and narrow; gills very large, nearly equal. Fig. 260 J/socardta cor. The heart-cockle burrows in sand, by means of its foot (/) leaying only the siphonal openings exposed. (Bulwer.) Distribution, 5 species. Britain, Mediterranean, China, Japan Fossil, 90 species. Trias —. United States, Europe, South India. The Isocardia-shaped fossils of the old rocks belong to the genera Cardiomorpha and IJso-arca ; many of those in the Oolites to Ceromya. Casts of true Jsocardie have only two transverse dental folds between the beaks, and no longitudinal furrows. CYPRICARDIA, Lamarck. Example, ©. obesa, Pl. XX., Fig. 4. C. rostrata, Fig. 261. Synonyms, Trapezium, Humph. Libitina, Sch. Shell oblong, with an oblique posterior ridge; umbones anterior depressed; ligament external, in deep and narrow grooves ; cardinal teeth 2.2, laterals 1—1 in each valve, some- times obscure ; muscular impressions oyal (of two elements); pallial line simple. ae 468 {ANUAL OF THE MOLLUSCA. Animal (of C. solenoides) with mantle-lobes united, cirrated behind ; pedal opening moderate ; foot small, compressed, with a large byssal pore near the heel; siphons short, conical, unequal, cirrated externally ; orifices fringed; palpi small; gills unequal, the outer narrower and shorter, deeply lamellated, united posteriorly, the inner prolonged between the palpi. Animal of Cypricardia rostrata, Lamarck, Philippines (Fig. 2B 300), with mantle-lobes united, Yj, 3S S\N ON; i / SEEawow’w..F”". ut Fig. 268. Glycimeris siliqgua, Chemn. Newfoundland. a, a, adductor muscle; p, pedal muscle; s, siphonal muscle; 7, foot; #, labial tentacles ; g, gills, much contracted and crumpled. pedal opening small anterior ; foot conical; palpi large, striated inside, the posterior border plain; gills large, extending into the branchial siphon. Distribution, 2 species. Arctic Seas, Cape Parry, North Western America, Newfoundland. Fossil, Piuocene—. Britain, Belgium. FAamMILy XIX.—ANATINIDA. Shell often inequivalye, thin; interior nacreous; surface eranular; ligament external, thin; cartilage internal, placed in corresponding pits and furnished with a free ossicle; muscular impressions faint, the anterior elongated; pallial line usually sinuated. Animal with mantle-margins united; siphons long, more or less united, fringed; gills single on each side, the outer lamina prolonged dorsally beyond the line of attachment. Pholadomya and its fossil allies have an external ligament only; has no ossicle. The external surface of these shells is often rough with large calcareous cells, sometimes ranged in lines, and covered by the epidermis; the outer layer consists of polygonal cells, more or less sharply defined; the inner layer is nacreous. ‘ ™ peasy lite VONCHIFERA, 495 ANATINA, Lamarck. Lantern-shell. Type, A. rostrata, Pl. XXIII., Fig. 7. (Anatinus, pertain- ing to a duck.) Synonyms, Laternula, Bolten MS. Auriscalpium, Muhlf. Osteodesma, Blainville. Cyathodonta (undulata), Conrad ? West America. Shell oblong, ventricose, sub-equivalve, thin and translucent, posterior side attenuated and gaping ; umbones fissured, directed backwards, supported internally by an oblique plate; hinge with a spoon-shaped cartilage process in each valve, furnished in front with a transverse ossicle; pallial sinus wide and shallow. Animal with a closed mantle and long united siphons, clothed with wrinkled epidermis; gills one on each side, thick, deeply plaited ; palpi very long and narrow; pedal opening minute, foot very small, compressed. Distribution, 20 species. India, Philippines, New Zealand. West America. Fossil, 50 species. Deyonian ?—Oolite—. United States, Europe. Sub-genera. Periploma (inequivalvis), Schum. ‘‘ Spoon- hinge” of Petiver ; oval, inequivalve, left valve deepest; pos- terior side very short and contracted. Distribution, West Indies, South America. Cochlodesma, Couthouy. C. preetenue, Pl. XXTII., Fig. 8. (Bontia, Leach MS. Ligula, Mont., part.) Oblong, compressed, thin, slightly inequivalve ; umbones fissured ; cartilage processes prominent, ossicle minute; pallial sinus deep. Animal witha broad, compressed foot; siphons long, slender, divided through- out; gills one on each side, deeply plaited, divided by an oblique furrow into two parts, the dorsal portion being narrower, com- posed of a single lamina only, and attached by its whole inner surface. (Hancock.) Distribution, 2 species. United States, Britain, Mediterranean. Jossil, Pliocene, Sicily. Cercomya, Agassiz. C. undulata, Sowerby. (=Rhynchomya, Agassiz.) Shell very thin, elongated, compressed, attenuated posteriorly ; sides concentrically furrowed, umbones fissured, posterior (cardinal) area more or less defined. Fossil, 12 species. Oolite—Neocomian. Europe. THRAcTA (Leach), Blainyille. Synonyms, Odoncinetus, Costa. Corimya, Agassiz. Rupicoia {concentrica\), Bellevue. 496 MANUAL OF THE MOLLUSCA Type, T. pubescens, Pl. XXIII., Fig. 9 Shell oblong, nearly equivalve, slightly compressed, attenuated and gaping posteriorly, smooth, or minutely scabrous; cartilage processes thick, not prominent, with a crescentic ossicle ; pallial sinus shallow. Outer shell layer composed of distinct, nucleated cells. Animal with the mantle closed; foot linguiform; siphons rather long, separate, with fringed orifices; gills single, thick, plaited; palpi narrow, pointed. T. concentrica and 7’. distorta, Mont., are found in the crevices of rocks, and burrows of Sawxicuva ; they have been mistaken for boring-shells. Distribution, 17 species. Greenland, United States, Norway, Britain, Mediterranean, Canaries, China, Sooloo; 4—110 fathoms. Fossil, 36 species. (Trias?) Lower Oolite—. United States, Europe. PHOLADOMYA, G. Sowerby. Recent Type, P. candida. Pl. XXII., Fig. 15. I. Tortola. Shell oblong, equivalve, ventricose, gaping behind; thin and translucent, ornamented with radiating ribs on the sides; liga- ment external; hinge with one obscure tooth in each yalve; pallial sinus large. Animal with a single gill on each side, thick, finery plaited, grooved along its free border, the outer lamina prolonged dorsally ; mantle with a fourth (ventral) orifice. (Owen.) | Distribution, 1 species. Tropical Africa. Fossil, 160 species. Lias—. United States, Europe, Algeria, Thibet. Homomya (hortulana), Agassiz. ‘Shell thick, concentrically furrowed, withe is x idiating ribs; 12 species. -Oolites, Europe. Tyleria, Adams. Cartilage inserted in a spoon-shaped hollow ; interior of shell with a layer of carbonate of lime between the spoon-shaped hollow and the anterior edge. MyacitTEs (Schlotheim), Bronn. Synonyms, Myopsis (Jurassi), Agassiz. Pleuromya, Agassiz, Arcomya (Helvetica), Agassiz. Mactromya (mactroides), Ag. Anoplomya (lutraria), Krauss. Example, M. sulcatus, Fleming. (Allorisma, King, Pal. Tr., — i340, Pl. XX., Fig; 5.) a Shell oblong, yentricose, gaping, thin, often concentrically — CONCHIFERA. 497 furrowed; umbones anterior; surface granulated; ligament external; hinge with an obscure tooth or edentulous; muscular impressions faint; pallial line deeply sinuated. Fossil, 50 species. Lower Silurian—Lower Chalk. United States, Europe, South Africa. Sub-genera ? Goniomya, Agassiz. Mya literata, Pl. XXII., Fig. 16. (Lysianassa, Minster, not M. Edwards.) Shell equi-~ valve, thin, granulated; ligament external, short, prominent. Fossil, 33 species. Upper Lias—Chalk. Hurope. Tellinomya (nasuta), Hall; Silurian, United States, Europe. Not, characterised. ? Grammysia, Werneuil. Nucula cingulata, His. Upper Silurian, Europe. Valves with a strong transverse fold extend~ ing from the umbones to the middle of the ventral margin. ? Sedgwickia (corrugata), M‘Coy. = ? Leptodonus (senilis), M‘Coy. Shell thin, ventricose, concentrically furrowed in front ; escutcheon long and flat. Silurian—Carb. urope. RIBEIRIA, Sharpe, 1853. Sheli gaping at both ends; sub-ovate, rounded in front, elon- gated and rather attenuated behind; punctate-striate ; casts cf interior with a large umbonal impression (caused by a cartilage- plate, as in Zyonsia ?) and a notch in front of it. Fossil. Lower Silurian. Portugal. CERomMYA, Agassiz. Etymology, keraos, horned, mya, mussel. Type, C. concentrica (Isocardia) Sowerby, Min. Con. 491, Fig. 1. Shell Isocardia-shaped, slightly inequivalve? very thin, granulated, often eccentrically furrowed; ligament external ; hinge edentulous; right valve with an internal lamina behind the umbo ; pallial line scarcely sinuated ? Fossil, 14 species. Inferior Oolite—. Greensand? Europe. Sub-genus ? Gresslya(sulcosa) Ag. (Amphidesma and Unio, species, Philippi). Shell oval, rather compressed; umbones anterior, incurved, not prominent; valves thin, close, smooth or concentrically furrowed; pallial sinus deep. Jossil, 50 species. Lias—Portlandian. Europe. The lamina within tho posterior hinge-margin of the right valve produces a furrow in the casts, which are more common than specimens retaining the S shell, . - 498 MANUAL OF THE MOLLUSCA. ? CARDIOMORPHA, Koninck. Type, C. oblonga (Isocardia), Sowerby (not Koninck). Car- bonate of lime. Shell Isocardia-shaped, smooth or concentrically furrowed, umbones prominent, hinge edentulous; hinge-margin with a narrow ligamental furrow, and an obscure internal cartilage groove. Fossil, 38 species. Lower Silurian—Carb. North America, Hurope. EDMONDIA, KONINCK. Example, EB. sulcata, Ph. (T. Pal. Soc. 1850, Pl. XX., Fig. 5.) Carb. Britain. Synonyms, Allorisma, King (part). Sanguinolites, M‘Coy (part ee oblong, equiyelve, thin, concentrically striated, close ; umbones anterior; lgamental grooves narrow, external ; hinge-line_ thin, edentulous, furnished with large oblique cartilage plates, placed beneath the umbones, and leaving space for an ossicle? or the plate may be equivalent to the sub-um- bonal blade in Pholas ; pallial line simple ? Fossil, 4 species. Carb.—Permian. Europe. Sub-genus. Scaldia, Ryckholt, 1856. Carb. Tournay. Shell like Hdmondia, with a single cardinal tooth in each valve. LyonsiA, Turton, 1822 (not R. Brown). Synonyms, Magdala, Leach, 1827. Myatella, Brown. Pan- dorina, Scacchi. Type, Li. Norvegica, Pl. XXIII., Fig. 10. Shell nearly equivalye, left valve largest, thin, sub-nacreous, close, truncated posteriorly ; cartilage plates oblique, covered — by an oblong ossicle; pallial sinus obscure, angular. Struc- ture intermediate between Pandora and Anatina ; outer layer composed of definite polygonal cells. Animal with the mantle closed; foot tongue-shaped, grooved, byssiferous; siphons very short, united nearly throughout, fringed; lips large, palpi narrow, triangular. Distribution, 12 species. Greenland, North Sea, Norway, West Indies, Madeira, India, Borneo, Philippines, Peru. 3 L. Norvegica ranges from Norway to the sea of Ochotsk; in 15—80 fathoms. ee aiads CONCHIFERA, 499 Fossil? Miocene—. Europe. (100 species. Lower Silurian— D’Orbigny. ) ? Entodesma (Chilensis), Phil. Shell thin, saxicaya-shaped, slightly inequivalye and gaping, covered with thick epidermis ; hinge edentulous; each valve with a semicircular process con- taining the cartilage. Panpora (Solander), Bruguiére. Type, P. rostrata, Pl. XXII., Fig. 11. (Pandora, the Grecian Hye.) Shell inequivalye, thin, pearly inside; valves close, attenuated behind; right valve flat, with a diverging ridge and cartilage furrows; left valve convex, with two diverging grooves at the hinge; pallial line slightly sinuated. Outer layer of regular, vertical, prismatic cells, 250 times smaller than those of Pinna (Fig. 217). (Carpenter.) Animal with mantle closed, except a small opening for the narrow, tongue-shaped foot; siphons very short, united nearly - throughout, ends diverging, fringed; palpi triangular, narrow ; gills plaited, one on each side, with a narrow dorsal border. Distribution, 18 species. United States, Spitzbergen, Jersey, Canaries, India, New Zealand, Panama; 4—110 fathoms, bur- rowing in sand and mud. Fossil, 14 species. Carb.—. United States, Britain. Myapora, Gray. Type, M. brevis, Pl. X-XTII., Fig. 12. Shell trigonal, rounded in front, attenuated and truncated behind ; right valve convex, left flat ; interior pearly ; cartilage narrow, triangular, between two tooth-like ridges in the left valve, with a free sickle-shaped ossicle; pallial line sinuated ; structure like Anatina ; outer cells large, rather prismatic. Distribution, 10 species. New Zealand, New South Wales, Philippines. MyocHaMa, Stutchbury. Type, M. anomioides, Pl. X XIII., Fig. 13. Shell inequivalve, attached by the dextral va.ve and modified by form of surface of attachment; posterior side attenuated ; left valve gibbose; cartilage internal, between two tooth-lke projections in each yalvye, and furnished with a movable ossicle; anterior muscular impression curved, posterior rounded, pallial sinus small. Animal with mantle-lobes united; pedal opening and siphon : 500 MANUAL OF THE MOLLUSCA. surrounded by separate areas ; siphons distinct, unequal, small, slightly fringed ; a minute fourth orifice close to the base of the branchial siphon ; visceral mass large, foot small and conical ; mouth rather large, upper lip hood-like; palpi tapering, few- plaited; gills one on each side, triangular, plaited, divided by an oblique line into two portions; excurrent channe's four, two at the base of the gills and two below the dorsal lamine. (Hancock, An. Nat. Hist., 1853.) Distribution, 5 species. New South Wales; attached to Crass- atella and Trigonia, in 8 fathoms water; the fry (as indicated by the umbones) is free, regular, and Myadora-shaped. CHAMOSTREA, Roissy. Type, OC. albida, Pl. XXITT., Fig. 14, Synonym, Cleidotheerus, Stutch. Shell inequivalye, chama-shaped, solid, attached by the anterior side of the deep and strongly-keeled dextral valve ; umbones anterior, sub-spiral; left valve flat, with a conical tooth in front of the cartilage ; cartilage internal, with an oblong, curved ossicle; muscular impressions large and rugose, the anterior very lone and narrow; pallial fe simple. Animal with mantle-lobes united by their extreme edge between the pedal orifice and siphons; pedal opening small, with a minute ventral orifice behind it; siphons a little apart, very short, denticulated; body oval, terminating in a small, compressed foot; lips bilobed, palpi disunited, rather long and obtusely pointed; gills one on each side, large, oval, deeply plaited, prolonged in front between the palpi, united posteriorly; each gill traversed by an oblique furrow, the dorsal portion con- sisting of a single lamina with a free margin. (Hancock, An. Nat. Hist., Feb., 1853.) Distribution, 1 species. New South Wales. FAMILY X X.—GASTROCHANIDA. Shell equivalve, gaping; valves thin, edentulous, united be 7 a ligament, sometimes cemented to a shelly tube when adult; adductor impressions 2, pallial line sinuated. ist Animal elongated, truncated in front, produced behind into — two very long ee contractile siphons, with cirrated orifices; mantle-margins very thick in front, united, leaving a small — opening for the finger-like root; gills narrow, prolonged i the branchial siphon. 4 The shell-fish of this family, the tubicolide of Lamarck, are- CONCHIFERA. 501 burrowers in mud or stone. They are often gregarious, living in myriads near low-water line, but are extracted from their abodes with difficulty. ; GASTROCHENA, Spengler, 1783. Type, G. modiolina, Pl. XXITI., Fig. 15. (Gaster, ventral, cheena, gape.) Shell regular, wedge-shaped, umbones anterior; gaping widely in front, close behind; ligament narrow, external; palhal sinus deep. Animal with mantle closed, and thickened in front; foo4 finger-like, grooved, sometimes byssiferous ; siphons long, sepa. rate only at their extremities; lips simple, palpi sickle-shaped, gills unequal, prolonged freely into the branchial siphon. G. modiolina perforates shells and limestone; its holes are regular, about 2 inches deep and 3 inch diameter ; the external orifice is hour-glass shaped, and lined with a shelly layer which projects slightly. When burrowing in oyster-shells it often passes quite through into the ground below, and then completes its abode by cementing such loose material as it finds intoa flask-shaped case, having its neck fixed in the oyster-shell; in some fossil species the siphons were more separated, and the flasks haye two diverging necks. ‘The siphonal orifices are rarely 4-lobed; Pl. XXIII, Fig. 15 a. Distribution, 10 species. West Indies, Britain, Canaries, Mediterranean, Red Sea, India, Mauritius, Pacific Islands, Gallapagos, Panama ;—30 fathoms. | Fossil, 20 species. Inf. Oolite—. United States, Europe. Sub-genus. Chena, Retz., 1788. C. mumia. Pl. XXIII, Fig. 16. (= Fistulana claya, Lam.) Shell elongated, con- tained within a shelly tube; posterior adductor nearly central, with a pedal scar in front; siphonal inflection angular, with its apex joining the pallial line. Tube round, straight, taper- ing upwards, transversely striated, closed at the lower end when complete, and furnished with a perforated diaphragm behind the valves. Distribution, 3 species. Madagascar, India, Philippines, Australia; burrowing in sand or mud, Fossil, Inf. Oolite—. United States, Europe, Southern India. Saxicava, Bellevue. Etymology, saxum, stone, cavo, to excayate. 8. rugosa, ) Pl. XXIL., Fig. 13. & 502 MANUAL OF THE MOLLUSCA. £ Synonyms, Byssomya, Cuy. Rhomboides, Bl. MHiatella (minuta), Daud., Biapholius, Leach. Arcinella (carinata), Phil. Shell when young symmetrical, with 2 minute teeth in each valve; adult rugose, toothless; oblong, equivalve, gaping, ligament external; pallial line sinuated, not continuous. Animal with mantle-lobes united and thickened in front; siphons large, united nearly to their ends, orifices fringed ; pedal opening small, foot finger-like, with a byssal groove ; palpi small, free; gills narrow, unequal, united behind and prolonged into the branchial siphon. Five genera and 15 species have been manufactured out of varieties and conditions of this Protean shell. It is found in crevices of rocks and corals, and amongst the roots of sea-weed, or burrowing in limestone and shells; at Harwich it bores in the cement stone (clay iron-stone), at Folkestone in the Kentish- rag, and the Portland stone employed. in the Plymouth Break- water has been much wasted by it. Its crypts are sometimes 6 inches deep (Couch); they are not quite symmetrical, and like those of the Zithodomus, are inclined at various angles, so as to invade one another, the last comers cutting quite through their neighbours; they are usually fixed by the byssus to a small projection from the side of the cell. The Saxicava ranges from low water to 140 fathoms; it is found in the Arctic Seas, where it attains its largest size; in the Mediterranean, at the Canaries, and the Cape. It occurs fossil in the Miocene tertiary of Hurope and in the United States, and in all the glacial deposits. CLAVAGELLA, Lamarck. Example, C. bacillaris, Pl. XXIII., Fig. 17. Shell oblong, valves flat, often irregular or rudimentary, the left cemented to the side of the burrow, when adult, the — right always free; anterior muscular impression small, posterior large, pallial line deeply sinuated. Tube cylindrical, more or — less elongated, sometimes divided by a longitudinal partition ; often furnished with a succession of siphonal fringes above, and terminating below in a disk, with a minute central fissure, and bordered with branching tubul. Animal with the mantle closed in front, except a minute slit for the foot, and furnished with tentacular processes; palpi long and slender; gills 2 on each side, elongated, narrow (floating freely in the branchial siphon ?). Some specimens of the recent C. aperta have 3 frills to their tubes, C. bacillaris has twice that number occasionally. They — CONCHIFERA. 903 are formed by the siphonal orifices when the animal continues elongating, after having fixed its valve and ceased to burrow; or perhaps, in some instances, when it is compelled to lengthen its tubes upwards by the accumulation of sediment. Brocchi mentions that on breaking the tube of the fossil C. echinata, he sometimes found the shell of a Saaxicava or Petricola beside the loose valve of the Clavagella, into whose tube they must have entered after its death. C. elongata is found in coral; (C. australis lives at low tide, and spirts out water when alarmed. Distribution, 6 species. Mediterranean, Australia, Pacific :— 11 fathoms. Fossil, 14 species. U. Greensand—. Britain, Sicily, Southern India. ASPERGILLUM, Lam. Watering-pot shell. Type, A. vaginiferum, Pl. XXIII., Fig. 18. Synonym, Clepsydra, Schum. Shell small, equilateral, cemented to the lower end of a shelly tube, the umbones alone visible externally; tube elongated, closed below by a perforated disk with a minute central fissure ; siphonal end plain or ornamented with (1—8) ruffles. Animal elongated; mantle closed, thickened and fringed with filaments in front; foot conical, anterior, opposed to a minute slit in the mantle; palpi lanceolate; gills long, narrow, united posteriorly, continued into and attached to the branchial siphon. | _ Distribution, 21 species. Red Sea, Jaya, Australia, New Zealand ; in sand. Fossil, 1 species. (A? Leognanum, Heening. Miocene, Bor- deaux. ) HUMPHREYIA, Gray. Shell developed in the substance of the siphons, which grow with the ventral side uppermost. Distribution, 1 species. South Sea. FAMILY X XI.—PHOLADIDE. Shell gaping at both ends ; thin, white, brittle, and exceedingly hard ; armed in front with rasp-like imbrications ; without hinge or ligament, but often strengthened externally by accessory valves; hinge-plate reflected over the umbones, and a long _curyed muscular process beneath each; anterior muscular im- pression on the hinge-plate; pallial sinus very deep. Animal club-shaped, or worm-like; foot short and truncated ; 594. MANUAL OF THE MOLLUSCA. mantle closed in front, except the pedal orifice; siphons large, elongated, united nearly to their ends; orifices fringed; gills narrow, prolonged into the exhalent siphon, attached through- out, closing the branchial chamber; palpi long; anterior shell- muscle acting as substitute for a ligament. The Pholadide perforate all substances that are softer than their own valves (p. 394) ;* the burrows of Pholas are vertical, quite symmetrical, and seldom in contact. The ship-worms (Teredines) also make symmetrical perforations, and however tortuous and crowded never invade each other, guided either by the sense of hearing or by the yielding of the wood. The burrow has frequently a calcareous lining, within which the shell remains free; Teredina cements its valves to this tube when full-grown. The opening of the burrow, at first very minute, may become enlarged progressively by the friction of the siphons, which are furnished with a rough epithelium; but it usually widens with much more rapidity by the wasting of the surface. As the timber decomposes the shelly tubes of the T'eredo project, and as the beach wears away the pholas burrows deeper. PuHouas, L. Piddock. Etymology, pholas, a burrowing shell-fish, from pholeo, to bore. Synonyms, Dactylina, Gray. Barnea, Risso. Type, P. dactylus, Fig. 269. Example, P. Bakeri, Pl. XXITI., Fig. 19. Shell elongated, cylindrical ; dorsal margin protected by acces- . sory valves; pallial sinus reaching the centre of the shell. Animal with a large truncated foot, filling the pedal opening; body with a fin-like termination ; combined siphons large, cylin- drical, with fringed orifices. * M. Cailliaud has proved that these valves are quite equal to the work of boring i limestone, by imitating the natural conditions as nearly as possible, and making such hole with them. Mr. Robertson also, has kept the living Fholades in blocks of chalk, b the sea-side at Brighton, and has watched the progress of the work. They turn fro side to side, never going more than half round in their burrow, and cease to work soon as the hole is deep enough to shelter them; the chalk powder is ejected at inter. vals by spasmodic contractions from the branchial siphon, the space between the she and burrow being filled with this mud. (Journ. Conch., 1853, p. 311.) It is to be re- marked that the condition of the Pholades is always related to the nature of the material in which they are found burrowing; in soft sea-beds they attain the large. size and greatest perfection; whilst in hard, and especially gritty rock, they dwarfed in size, and all prominent points and ridges appear worn by friction. N notice has been taken of the hypothesis which ascribes the perforation of rocks, &c., to ciliary action, because, in fact, there is no current between the shell or siphons an the wall of the tube. ’ j y 4 ¥ CONCHIFERA. 0045 - The common piddock is used for bait on the Devon coast ; its footis white and translucent when fresh, like a piece of ice; the hyaline stylet (p. 22) lodged in it, is large and curious. P. costata is sold in the market of Hayannah, where it is an article of food. P. dactylus has two accessory valves to protect the umbonal muscle, with a small transverse plate behind; a long unsym- —— KE —= } = = ; — < eS =n Dp a pe eee aa 33a = fal) } , a % Tee Haas ) a082 NOES SOC te ee SS 5S ] 4 = Pr as Fig. 269. Pholas dactylus. Chalk, Sussex Coast. u, umbonal valves; p, post-umbonal valve; d, dorsal valve. metrical plate fills up the space between the valves in the dorsal region. P. candida and parva have a single umbonal shield, and no dorsal plate; these differences are only of specific value. In P. crispata, L. (Zirfoea, Leach), the umbonal shield is not dis- tinctly calcified, but there is a small posterior plate; the surface of the yelves is divided into two areas by a transverse furrow Distvibution, 32 species. United States, Norway, Britain, Western Africa, Mediterranean, Crimea, India, Australia, New Zealand, Western America :—25 fathoms. Fossil, 25 species. (U. Lias—) EHocene—. United States, Europe. The secondary species belong to the next group. PHOLADIDEA, Turton, 1819. Type, P. papyracea, Pl. X XIII., Fig. 20. Shell globose-oblong, with a transyerse furrow ; anterior gape large, closed in the adult by a callous plate; 2 minute accessory valves in front of the beaks. Animal with a fringed disk at the end of the combined aIphenes and a horny cup at their base. Distribution, 7 species. Britain, New Zealand, Reuator, Low tides—10 fathoms. Sub-genera, Martesia (Leach), Bl 1825. M. striata, Pl. XXITI., Fig. 21. Valves lengthened behind, when full grown, by a plain border; umbonal valves 1 or 2; dorsal and ' ventral margins often with narrow accessory valyes. 11 species. West Indies, Africa, India. MV. striata burrows in hard timber. Z 506 MANUAL OF THE MOLLUSCA. M. teredintformts was found in cakes of floating wax on the coast of Cuba. (G. B. Sby.) I. australis in (fossil ?) resin, on the coast of Australia. J. rivicola in timber twelve miles from the sea, in Borneo. WM. scutata, Eocene, Paris, lines its burrow with shell. Jouannetia (semicaudata), Desm. (Pholadopsis, Conrad ; Triomphalia, Sby.) Shell very short, sub-globose; right valve longest behind ; anterior opening closed bya callous plate deve- loped from the left valye overlapping the margin of the right valve, and fixed to the single unsymmetrical umbonal plate. Distribution, 4 species. Philippines, Western America. Jossil, Miocene —. France. Parapholas, Conrad, P. bisulcata, Pl. XXITI., Fig. 22. Valves with 2 radiating furrows. Distribution, 4 species. Panama, Torres Straits. XYLOPHAGA, Turton. Hitymology, xulon, wood, phago, to eat. Types, X. dorsalis, Pl. XXIII., Fig. 23; X. globosa, Sby. Valparaiso. Shell globular, with a transverse furrow; gaping in front, closed behind; pedal processes short and curved; anterior margins reflected, covered by 2 small accessory valves; burrow oval, lined with shell. ; Animal included within the valves, except the slender con- tractile siphons, which are furnished with pectinated ridges, and divided at the end; foot thick, very extensile. Distribution, 2 species. Norway, Britain, South America. Bores an inch deep, and across the grain, in floating wood, and timbers which are always covered by the sea. TEREDO (Pliny), Adanson. Type, T. Norvegica, Pl. XXIII., Figs. 26, 27. Synonyms, Septaria, Lamarck. Hyperotis, Guettard. Shell, globular, open in front and behind, lodged at the inner extremity of a burrow partly or entirely lined with shell; valves 3 lobed, concentrically striated, and with one transverse furrow ; hinge-margins reflected in front marked by the anterior muscu- lar impressions; umbonal cavity with a long curved muscular process. Animal worm-like ; mantle-lobes united, thickened in front, with a minute pedal opening; foot sucker-like, with a foliaceous border; viscera included in the valves, heart not pierced by the intestine; mouth with palpi; gills long, cord-like, extending CONCHIFERA. 507 into the siphonal tube; siphons very long, united nearly to the end, attached at the bifurcation and furnished with 2 shelly pallets or styles ; orifices fringed. T. Navalis is ordinarily a foot long, sometimes 23 feet; it destroys soft wood rapidly, and teak and oak do not escape; it Fig. 270. Ship-worm, Teredo Norvegica, removed from its burrow. always bores in the direction of the grain unless it meets the tube of another Zeredo, or a knot in the timber.* In 1731-2 it did great damage to the piles in Holland, and caused still more alarm; metal sheathing and broad-headed iron nails have been found most effectual in protecting piers and ship-timbers. The Teredo was first recognised as a bivalve mollusc by Sellius, who wrote an elaborate treatise on the subject in 1733. (Forbes.) T. corniformis, Lamarck, is found burrowing in the husks of cocoa-nuts and other woody fruits floating in the tropical seas; its tubes are extremely crooked and contorted, for want of space. The fossil wood and palm-fruits (Nipadites) of Sheppy and Brabant are mined in the same way. ‘The tube of the giant Teredo (7. arenaria, Rumph. Furcella, Lamarck) is often a yard long and 2 inches in its greatest diameter; when broken across it presents a radiating prismatic structure. The siphonal end is divided lengthwise, and sometimes prolonged into two diverg- ing tubes. JZ’. Norvegica and 7. nana are divided longitudinally and also concamerated by numerous, incomplete transverse partitions at the posterior extremity. T. palmulata (Xylotrya, Leach) has the siphonal pallets elon- gated and penniform (Pl. XXIII., Fig. 28); a species with similar styles occurs in the fossil wood of the Greensand of Blackdown. . Distribution, 21 species. Norway, Britain, Black Sea; Tro- pics :—119 fathoms. Fossil, 24 species. Lias—. United States, Europe. Sub-genus. Teredina, Lamarck. TT. personata, Pl. XXIII, Figs. 24, 25. Eocene, Britain, France. Valves with an acces- sory plate in front of the umbones; free when young. The tube is sometimes concamerated; its siphonal end is often ‘truncated ; and the opening contracted by a lining which makes it hour-glass shaped, or six-lobed (Fig. 25 a.). * The operations of the Zeredo suggested to Mr. Brunel his method of tunnelling the Thames, INDEX. Tlic synonyms are printed in italics, and the pages where the genera are described aré Abbreviations, 49. Abra, 483, Abralia, 171. Acanthina, 223. Acanthochites, *284. Acanthodoris, *332. Acanthopleura, *283. Acanthoteuthis, *175. Acanthothyris, 375. Acardo, 323, 454. Acavus, *289. Acephala, 5. Acera, *316, 319. Achatina, *292. Achatinella, *292, Acicula, *310. Aciculide, *310. Aclesia, *321, Aclis, *240. Acmeza, #281, Acmaea, 311. Acme, 311. Acceli, *174. Alcostea, 435. Acroculia, 277. Acrolorus, 302. Acrotreta, *390, Acton, 313, 339. Acteonella, *314, Acteonia, *339. Acteonina, *314, Actinocamaz, 175. Actinoceras, *191. Actinoconchus, 373, Actinocyclus, *329. Actinodonta, 432. Acuarii, #174. Acus, 220. Adacna, *454, Adamsiella, *308. Adductor impressions, 401. Adelopneumona, 285. Adeorbis, *266. Admete, 55, *216, 4#gean Sea Shells, 67. Z@cirus, 327, *330, Anigma, 408. fEolide, *335. A®olis, 328, *335, fEstivation, 13, Aétheria, *435, Affinities, 45. indicated by an asterisk (*). African region, 97. Aganides, 196. Agaronia, *227. Agina, 490. Alasmodon, 433. Alcadia, #310, Aleynus, 265. Alderia, *338. Aleutian province, 76. Alexia, *305. Alicula, 316. Allorisma, 496, 498. Alvania, 240. Amalthea, *278, Amalthei, *198. Amathina, *277. Ambonychia, *417. Amicula, 284. Ammonites, 35, 37, *197. Ammonitide, *195, Amnicola, *247, Amoura, 239. Amphibola, *259. Amphibulima, 290. Amphiceras, 234. Amphicheena, *486. Amphidesma, 431, 483, 497 Amphidonta, 407. Amphipeplea, *301. Amphisphyra, *317. Amphorina, 335. Ampulina, 236. Ampullacera, 259. Ampullaria, 14, 27, 32, *258. Ampuitina, 310. Amusium, 411. Amusium, *412. Anadenus, *296. Analogies, 45. Anapa, *485. Anastoma, *289, Anatina, *495. Anatina, 431. ‘Anatinella, #479. ‘Anatinide, *494, Anatomus, 269. Ancillaria, 24, *227, ‘Aneistrochirus, 171. ‘Ancistroteuthis, 171. Ancula, 327, *331. na Anculotus, 247. Ancyloceras, *200. Ancylus, 287, *302, Aneitea, *297. Anisoceras, 200. Annulati, *199. Annulosa, 2. Anodon, 30, *434. Anolax, *220. Anomalocardia, 424, 473. Anomia, 19, *408. Anoplomya, 496. Anoplotheca, *879. Anops, 342. Anthracosia, *470. Antigone, 473. Antilles, shells of, 110. Antiopa, *337. Aperostoma, 308. Aperture, 206, Apex, 205. Apvwoceras, 193. Apleza, 302. ’ Aploceras, 194. Aplustrum, *318, A Aplysia, 11, 22, 23, 24,*320, Aplysia, 321. Aplysiadee, *320. Aporrhais, 211, *244. Aptychus, 182. Aquiferous system, 24, Arabian shells, 98. Aralo-Caspian prov., 68, Arca, 30, 395, *424, Arcadee, *424, Architectoma, 253. Arcinella, 437, 471, 502. Arcomya, 497. Arctica, 464. Arctic province, 57—59. Areopagia, 480. Argentine region, 114, Argiope, *368. 7 Argonauta, 28, 31, 39, 56, *161. : Argus, 411. tea *198. Arion, *296. Ariophanta, *290. Armati, *198. Artemis, *474. Articulated operc., 208, Ascoceras, 189. Asiphonida, 406, Asolene, *259. Aspergillum, 55, *503. Assiminea, 256. Astarte, 33, 55, *464. Astartela, 469. Asteronotus, *329. Atagema, *329. Athoracophorus, 297. Athyris, *373. Atlanta, 29, 341, *344. Atlantide, *343. Atlas, *320. Atrypa, *378. Aturia, #189. Atys, 316. Aucella, *416. Aulonotreta, 392. Aulopoma, 308. Aulosteges, *385. Aulus, 482. Auricella, 305. Auricula, *304. Auriculide, 36, *303. Auriscalpium, 495. Australian region, 103. Australian shells, 74. Avellana, 314. Avicula, 30, #415. Aviculidx, *415. Aviculo-pecten, *417. Axinus, *431. Axis uf shell, 205. Azara, 499. Azeca, *292. Azores, shells of the, 65, 94 Bachybathron, *225. Bactrites, *197. Baculites, *201. Bakewellia, *418. Baiantium, 349. Balea, *293. Balearic Isles shells, 92. Baphia, 433. Barbatia, 424. Barnea, 504. Base of shell, 206. Baitillus, 263. Batissa, *463. Bela, *229. Belemnitella, *175. Belemnites, *173. Belemnitide, *173. Belemnosepia, 168. Belemnosis, *177. Belemuoteuthis, *175. Bellerophina, *345. Bellerophon, *344. Belopeltis, 168. Beloptera, *177. Belosepia, 177. Beloteuthis, #168. Berthella, 322. Bezoardica, 224, Biapholius, 502. Bifrontia, *253. Biradiolites, *448. INDEX. Birostrites, 447. Bithynia, 33, *258. Bittium, *242. Black Sea shells, 67. Body whorl, 206. Bolitena, *166. Bonellia, 240. Bontia, 495. Boreal province, 60, 61. Boring, 394. Bornean shells, 102. Bornella, *333. Bornia, 459. Borsonia, *229, Bostrycheteuthis, 165. Bouchardia, *366. Bourciera, 307. Brachionobranchia, 5. Brachiopoda, range in time, 128 Brachiopoda shell, 32. Brachychlamis, *332, Brachydontes, 421. Brachypus, 293. Branchia, 26, Brazil, shells of, 112. Brocchia, 277. Brochus, 249. Broderipia, *267. Brownia, *284, Bucardium, 467. Buccinanops, 220. Buccinide, *218. Buccinulus, *318. Buccinum, 55, *219. Buchanania, *299, Buckie, 218. Bulimulus, *291. Bulimus, 15, 32, 36, 37, 44, 111—113, *291. Bulin, 301. Bulinus, 291. Bulla, *316. Bulla, 315. Bullea, 318. Bullia, 220. Bullide, *315. Bullina, 317, 318. Bullinula, 318. Bursatella, 321, Busiris, *321. Bysso-anodonta, 434, Bysso-arcea, 424, Byssomya, 502. Byssus, 19. Czecum, *249, Calcar, 264. Calcarella, *284. Calceola, *383. Californian province, 78. California, shells of, 109. Callia, 309. Calliopza, *336. Callo-chiton, 283. Callopoma, 263. Calma, *337. Calpurna, *234. Calpurnus, 234, 509 Calypeopsis, *276, Calyptrea, *276. Calyptreide, *275. Camarophoria, *376, Cameroceras, *191. Camptoceras, *302. Campulites, 194. Campulote, 224. Campyloceras, 194. Canadian region, 106. Canal, 206. Canaliculati, *174. Canary Isles shells. 65, 94+ Cancellaria, 55, *216. Canthiridus, 265. Cape region, 97. Capisterium, 485. Caprella, 291. Capricorni, *198, Caprina, *450. Caprinella, *448. Caprinula, 448. Caprotina, *451. Capsa, 481, 486. Capsula, *481. Capulus, 277. Carbonicola, 470. Cardiade, *453. Cardiapoda, *243, Cardilia, *46y. Cardinalia, 264. Cardinal teeth, 401. Cardiocardita, 471. Cardinia, *470. Cardiola, *417. Cardiomorpha, 467, *498. Cardissa, 454. Cardita, *471. Cardium, *453. Carinaria, 9, 12, 29, 341, *343, Carinaroides, 343. Carocolla, *289. Carolia, *410. Cartilage, 400. Carychium, *305. Casella, *352. Cassiani, *199. Cassidaria, *225. Cassidula, 217, 304. Cassis, 32, 38, *224, Castalia, *434. Catantostomata, *270. Cataulus, *309. Catillus, 419. Cavolina, *335, Cavolina, 348, Celtic province, 61L—63. Cemoria, 274. Cenia, *339. Cepa, 408. Cepatia, 235. Cephalopoda, 4, 27, 155. Cephalopoda, range ia time, 127. Ceratisolen, *487, Ceratites, *197. Ceratosoma, *331, Cercomya, *495. (610 Ceriphasia, *247. Cerithiade, *242. Cerithidea, 36, *243. Cerithiopsis, *242 Cerithium, *242. Cernina, *236. Ceromya, 467, *497. Ceronia, *485. Cerophora, 342. Ceylonese shells, 100. Cheena, *501. Chalidis, 340. Chama, 38, 131, *437. Chamidz, *437. Chamostrea, *500. Cheiroteuthis, *170. Cheletropis, 212, 352. Chelidonura, *319. Chemnitzia, *239. Chenopus, 245. Chili, shells of, 114. Chilinia, *301. Chilostoma, *247. Chinese snails, 101. Chione, 473, 485. Chiorera, *338. Chironia, 459. Chiton, 23, 28, *282, Chitonellus, *284. Chitonide, *282. Chlorostoma, 264. Choanopoma, *307, 308. Chondropoma, 307. Chondrosepia, 168. Chonetes, *326. Choristites, 371. Choristodon, 476. Chorus, 223. Chromodoris, *329. Chrysodomus, 55, *218. Cilia, 42. Cingula, 255. Cinulia, *314, Cionella, 292. Circe, *464. Circulatory system, Brach- iopoda, 358. Cirroteuthis, *165. Cirrus, *271. Cistopus, 163. Cistula, *307. Cithara, *229, Clanculus, 265. Classification, 45. Clausilia, 37, 286, *294. Clausina, 456. Clavagella, *502. Clavati, *174. . Clavatula, *229, Clavella, *218. Clea. 247 Cleidophorus, 468. Cleidotherus, 500. Cleiothyris, 373, 378. Clementia, *475. Cleobis, 469. ee 347, *349. Clepsydra, 503. Cliidz, *353. INDEX. Climate, inf. of,on dist.,53. Clio, *353. Clio, 249, Cliodita, *853. Cliona, 34. Clione, 353. Clionella, *229. Clelia, 336. Clymenia, *190. Coccoteuthis, 168. Cochkdium, 217. Cochlitoma, 292. Cochlodesma, *495. Cochlodina, 294. Cochlohydra, 290. Codakia, 456. Ccelenterata, 2. Coleoprion, *350. Collar of mantle, 34. Collecting shells, 136. Collonia, *266. Colour of shells, 38. Columbella, 55, *226. Columbian region, 111. Columbinella, 227, Columella, 205. Columna, 292, Colus, 218. Cominella, 219. Concentric operc., 207. Conchifera, 5, 393. Conchifera, range in time, 128. Concholepas, *222, Congeria, 423. Conide, *228. Conocardium, *454. Conoceras, 190. Conoheliz, 216. Conorbis, 228. Conoteuthis, *176. Conotubularia, 192. Conovulus, *304, Conradia, *253. Conularia, 2, 346, *850. Conus, 12, 24, 32, 33, 36, 55, *228. Coralline zone, 152. Coralliophaga, *468. Corbicula, *462. Corbis, *457. Corbula, 457, 490, 491. Corbulomya, 490. Corephium, 284. Coret, 302. Corimya, 495. Coriocella, 237. Corniculina, 249, Coronati, *199. - Corsican snails, 92. Coryphella, *335. Couthouyia, *253. Cranchia, *169. Crania, 42, *386. Craniade, *386. Craspedopoma, *309. Crassatella, 55, *466, Crassina, 464, Crenatula, *418 Crenella, 43, 55, *422, Crepidula, *278, Creseis, *349. Creseis, 350. Crimora, *332. Crioceras, *199. Criopus, 386. Cristati, *198. Crossostoma, *266. Crucibulum, *276. Crypta, 277. Cryptella, 297. Cryptina, 431. Cryptocella, *238, Cryptoceras, *189, Cryptochiton, 284, Cryptoconchus, 284. Cryptodon, *456. Cryptogramma, 474. Cryptophthalmus, *316, Cryptostoma, 236. Crystalline stylet, 22. Ctenoconcha, 429. Ctenodonta, 427, Cucullea, *425. Cucullella, *427, Cultellus, *487. Cuma, *222. Cumingia, *483. Cuneus, 474, 485. Curtonotus, *431. Curve of shells, 204, Cuspidaria, 491, Cuthonia, *337. Cuttle fish, 8. Cuvieria, *349, Cyamium, *458, Cyathodonta, 495. Cycladide, *461, Cycladina, 459. Cyclas, 15, 29, 397, *461, Cyclidia, 182. Cyclina, *475. Cycloceras, 190. Cyclonassa, 221. Cyclophorus, *308. Cyclostoma, 266. Cyclostoma, *306. Cyclostomide, *306, Cyclostrema, *266. Cyclothyris, 375. Cyclotopsis, 308. Cyclotus, *808, Cylichna, *317. Cylindra, *231, Cylindrella, 36, *293, Cylindrites, *313, Cyllene, *221. Cymba, 28, *231. Cymba, 278. Cymbiola, 230. Cymbulia, *351. Cymodocea, *354. Cynodonta, 216. Cyprea, 12, 24, 32, 25, 37 55, *232. Cypracassis, 224, Cypreide, *232. Cypricardia, “47 icardites, 422, 468. one 33, 55, *463. Cyprinide, *463. Cyprovula, *233. Cyrena, *462. Cyrenella, 463. Cyrenoides, *463. Cyrtia, *372. Cyrtoceras, *194, Cyrtodaria, 493. Cyrtolites, *345. Cyrtulus, 218. Cytherea, 473. Dactylina, 504. Dactylus, 313. Daphnella, 229. Daudebardia, *290, Davidsonia, *382. Davila, *485. Decapoda, *166. Decollated shells, 36, 206. Defrancia, 229. Delphinoidea, 256. Delphinula, 266. Delthyridega, 365. Delthyris, 371. Dendrodoris, 328. Dendronotus, 327, *334. Dendrostrea, 408. Dentaliade, *282. Dentalium, 27, *282, Dentati, *198. Dentition, 208. Dentition formula, 401. Deridobranchus, *268. Dermi-branchiata, 339, Deshayesia, *236, Desmoulinsia, 221. Development, 41, 287. Diacria, 348. Diadora, 274. Dianchora, 414, Dniaphana, 317. Dibaphus, *216. Dibranchiata, *156. Diceras, *439, Dicelosia, 380. Didacna, 454, Digitaria, 465. Dimya, 408. Dimyary, 402. Diodonta, 481. Dione, 474. Dicecious, 40, Diphyllidia, *325. Dipilidia, 438. Diploceras, 192. Diplodonta, 455, *458. Diplommatina, *309. Disci, *198. Discina, 357, *388, Discinide, *388, Discites, *189. Discites, 411. Discohelix, 253. Discosorus, *193. Dispotea, 276. Dithyra, 393. INDEX. Ditremaria, 271. Dolabella, *321. Dolabra, 431. Dolabrifera, *321. Dolium, 36, *225. Dombeya, 301. Donacilla, 485. Donacina, 486. Donax, *485. Doride, *328. Doridium, *319. Doris, 14, 24, 327, *328. Dorsanum. 220. Dosidicus, *173. Dosinia, 474, 475. Doto, 334. Dredging, 140. Dressena, 37, *423. Drillia, *229. Eburna, *221. Ecculiomphalus, *845. Echinospira, 285. Edmondia, *498, Egeria, 485, 486. Eggs, 40. Eglisia, 248. Evidothea, 319. Elasmatina, 294, Electrina, 310. Eledone, 27, *165. Elenchus, 12, *265. Elysia, *339. Elysiade, *339. Emarginula, *275. Eimbla, 491, Embletonia, *336, Embryo, 44. Encephala, 3. Endemic species, 51. Endoceras, *192. Endosiphonites, 190. Enida, 265. Enoplo-chiton, 284 . Enoploteuthis, *171. Ensatella, 487. Ensis, 487. Enieletes, 380. Entodesma, *499, Enzina, 214. Eolis, 23, 40. Epidermis, 33, 400. Epiphragm, 288, Epithyris, 363. Erato, *234. Erodona, 490. Ervilia, *485. Erycina, 459, 473, 483, 484. Erryz, 484. Escutcheon, 400. Eubranchus, 335. Eucharis, *492. Eudesia, 365. Eulima, *240. Eulimella, *239, Eumenis, 334. Euomphalus, 36, *267, 346. Euphemus, 344. Euplocamus, 331. 51 Eurybia, *350. Eurydesma, *417. Eurydice, 338. Euthria, 214. Eutropia, 263. Exogyra, *408. Eyes, 16. Facelina, *335. Falciferi, *198. Families, 46. Farcimen, 309. Fasciolaria, *215. Fastigiella, *244. Faunus, 248. Favorinus, *337. Felania, 458. Fenestrella, 408. Ferussina, 308. Fibrous shells, 31. Ficula, 217. Filurus, *337. Fimbria, 333, 457. Fimbriati, +199. Fiona, *336. Firola, 9, 341, *342. Firolide, *342. Firoloides, *342, Fissirostra, 365. Fissurella, 27, *272. Fissurellide, *272. Fissurellidexa, *273. Fistulana, 35. 501. Flabellina, *335. Food, 8, 9. Formation of shells, 34. Forms of shells, 36. Fossarus, 131, *253 Fragilia, 481. Fryeria, *325. Fucola, 339. Fulgur, *217. Funnel, 187. Fusulus, 293. Fusus, 29, 35, 37, *218. Fusus, 212. Gadinia, *281. Galapagos Islands, 112, Galapagos Isles shells, 80, Galatea, *486. Galeomma, *461, Galerus, 276. Galvina, *337. Ganglia, 16. Gari, 482. Gasteropoda, 4, Gasteropoda, time, 128. Gastrana, *481, Gastrana, 476. Gastridium, 219. Gastrochena, *501. Gastrocheenide, *560, range im . Gastroceeli, *174, Gastroplaz, 323. Gastropteron, *319 Gellina, 334 Gena, *267. 512 Genera, 46, 52. Generic areas, 52, 53. Genetic affinity, 45. Geographical dist., 50. Geological strata, 118. Geomalacus, *296. Geomelania, *811,. Geoteutiis, *168. Geotrochus, *289, Geovula, 304. Germanic region, 89. Gervillia, *418. Gibbula, *265. Gibbus, *291. Gizzard, 22, Glandina, 286, *292. Glaucomya, *477. Glauconella, 316. Glauconome, 477. Glaucus, *336. Globiconcha, *814, Globulus, *236. Glossodoris, *329, Glossus, 467. Glottella, 247. Glycimeris, 55, *493. Gnathodon, *478. Goldfussia, *469. Gomphoceras, *193, Gonambonites, 380. Gonatus, *168. Goniatites, *196. Gonioceras, 190. Goniodoris, *830. Goniomya, *497. Goniophora, 468. Goodallia, 464. Gouldia, *465. Grammysia, *497. Grateloupia, *474. Gresslya, *497. Growth of shell, 34. Grypheza, 35, *408. Gryphochiton, 284, Gryphus, 363. Guard, 173, 174. Gulf-weed banks, 64. Gundlachia, *303. Gymnodoris, *332. Gymnosomata, *353. Gypidia, 377. Halia, *220. Haliotide, *268. Haliotis, 24, 27, *268. Halobia, 417. Halopsyche, 350. ‘aminea, 316, Yanites, *201. Hamulina, 201. Harpa, 55, *226. Pease, 230. Harvella, *478. Hastati, *174. Head, 42, Heart, 24, 42. Hectocotyle, 159—163, Hecuba, 485, Helcion, 278, INDEX. Helicarion, 290. Helicella, *289. Helicerus, *178, Helicide, *288. Helicina, *300. Heiicuna, 265. Helicoceras, *200. Helico tus, 253. Policies: 290, Heliconoides, 352. Helicophanta, 290. Hlelicophlegma, 344. Helicteres, 292, Helisiga, 290. Helix, 11, 14, 38, 85, $7, *288. Helix distribution, 87. Helminthochiton, 284. Hemicardium, *454. Hemicyclonosta, 469. Hemidoris, 328. Hemimitra, 247. Hemipecten, *412, Hemiplacuna, 410, Hemipronites, 380. Hemisinus, *247. Hemithyris, 375. Hemitoma, *274. Heptabranchus, *329. Hermea, 338. Heteroceras, *200. Heterofusus, 352. Heterogangliata, 2. Heterophylli, 199. Heteroteuthis, 170. Hettangia, 457, Hexabranchus, *329, Hiantula, 273. Ffiatella, 461, 502. Hinge line, 401. Hinnites, *412., HHippagus, 472. Hipparionyz, 378. Hippochrenes, 212, Hippomya, *423. Hipponyx, 7, *278. Hippopodium, *471. Hippopus, *453. Hippurites, 32, *443, Hippuritide, *440. Fiirundinelila, 319. Histioteuthis, *170. Holopea, *272. Holostomata, *234, Homogangliata, 2. Homoiozoic belts, 54. Homologies of shell, 39. Homomya, *496. Hoplomytilus, *423, Hlortolus, 189. Humphreyia, *503. Huronia, *191. Hyalzea, *348. Hyaleide, *348, Hyalina, *232, Hyaloteuthis, 172. Hybernation, 39, 40, Hybocystis, *309 Hybrids, 46. Hydatina, 318, Hydrobia, *256. Hydrocena, 307. Hyolites, 191. Hyperotis, 506. Hypobrancheea, *325, Hypodema, 383. Hypogea, 487. Hypostoma, *289. Hypothyris, 375. Hypotrema, *418. Hyria, *434, Hysterolites, 379, Ianthina 28, 31, *271. Icarus, *322. Ichthyosarcolites, 450. Idalia, *331. Jdotea, 457. Imbricaria, .*231. Imbricated opere., 207. Imperator, *264. Imperforate shells, 205. Impregnation of egg, 41, - Incilaria, *296. Indian region, 99. Indo-Pacific provinee, 71, Infero-branchia, 312. Infundibulum, 264, 276, Ink bag, 157, 173. Inoceramus, 31, *419, JInoceramus, 491. Inoperculata, 285. Integro-pallialia, #436. lo, 247. Iphigenia, *486, Ischnochiton, 283. Jsidora, 301. Ismenia, *368. Isoarca, *427, 467, Isocardia, *466. Lsocardia, 431. Jsodonta, 478, 486. Lsognomon, 418, Itieria, 314. Jamaica, shells of, 110, Jamaicia, 307. Jaminea, 239. Janella, *297. Janus, 337. Japanese snails, 101, Japonic province, 75. Jasonilla, 285. Javanese shells, 102, Jeffreysia, *256. Jouannetia, *506 Kalceno, 175, Katharina, *284, Kellia, *459. Kingena, *368 Kleinella, *317, Koninckia, *581, Kraussia, *867. Labio, 265. Lachesis, *229, * Lacuna, 55, *255, 344. Eadas, | Levigati, *189, era, 216 Lajonkairia, 475. ~ Lamellaria, *237. - Lamellibranchiata, 5, 393. Laminarian zone, 151. ~ Lampania, *244, Lampas, 363, _ Land provinces, 51. _ Laniogerus, 336. _Taanistes, *259. Lanistes, 422, Lasea, 459. Lateral teeth, 401. Laternula, 495. Latia, *302. Latirus, 216. _ Latona, 485. ¥ Latrunculus, 221. _ Leachia, 170. ~ Leda, 427. Leguminaria, 488. _ Leila, 435. - Leiodomus, 220. _ Leiostoma, 218. _ Lembulus, 427, Leonia, 306. Lepeta, *281. _ Leptena, 380, 381. _ Leptagonia, 380. _ Lepto-chiton, 283. _ Leptoconchus, 224, Leptodonus, 497. -Lepton, *460. Leptopoma, *308. - Leptoteuthis, *169. Leucostoma, 223. Leucotina, *241. | Leucotis, 237. - Levenia, 224, Liarea, 307. Libitina, 467. Ligament, 400. - Ligati, *199. _ Lagula, 484, 495. — Liguus, 292. Lima, 11, *412. _Limaceilla, 296. Limacide, *295. _Limacina, *351. -Limacinide, *351. Limea, *413. -Limanomia, *409. -Limapontia, *340, -Limatula, *413. Limax, *295. Limnea, *300. INDEX. Listera, 484. Lithedaphus, 276. Lithidion, 306. Lithocardium, *454, Lithodomus, 34, *422. Lithoglyphus, *257. Litiopa, 8, *255. Littoral zone, 151. Littorina, 37, *250, 286. Littorinide, *250. Lituites, *189, Lituus, 174. Liver, 22. Livona, 264, Lobaria, 482. Lobiger, *322. Loligo, *167. Loligopsis, *170. Loligosepia, 168. Loliolus, 168, 172. Lomanotus, *334. Lomastoma, *309, Lophocercus, 322. Lophurus, 283. Loripes, 456. Lottia, 281. J.oxonema, *241. Lucapina, *273. Lucidella, *310, Lucina, 38, 56, *456. Lucinide, *455. Lucinopsis, 131, *475. Lunatia, *236. Lunularca, *427. Lunulocardium, 454, * Luponia, *233. Lusitanian region, 91—97. Lusitanian prov., 63, 67. Lutraria, *479. Lutricola, 484. Lychas, 454. Lychnus, *289, Lyonsia, 422, 498, Lyra, *365. Lyriodon, 430. Lyrodesma, *432, Lysianassa, 497. Macgillivrayia, 225, 352. Macha, 488. Machera. *488. Maclurea, *345. Macrocheilus, *241. Macrodon, *425, Macroschisma, *273, Mactra, 24, *477, Mactra, 431. Mactrella, *478. Mactridez, *477. Mactrinula, 478. ‘ Mactromya, 457, 484, 496. Madagascar shells, 98. Madeiran shells, 65, 92, Mevnia, 468. Magas, *366. Magdula, 498. Magellanica, 365. Magellanic province, 82. Magilus, 36, *224, Zo 513 Matea, *226. Malletia, 429. Malleus, *416, Mamiilla, 235. Mangelia, *229, Mangelia, 229. Mantle, 34. Margarita, 55, *265. Margaritana, 433. Margaritophora, 416. Marginella, 55, *232. Marine provinces, 51, 54 Marinula, 304, Marisa, *259, Marmorostoma, 263. Marsenia, 237. Martesia, *505. Martinia, 371. Mauritius shells, 99. Mediterranean shells, 65 Medoria, 255. Megadesma, 486. Megadesmus, 470. Megalodon, *469. Megaloma, *469, Megalomastoma, 809. Meganteris, *365. Megusiphonia, 189. Megaspira, 286, *294, Megathyris, 368. Megatrema, 278, Megerlia, *367. Meghimatium, 296. Meladomus, *259. Melafusus, *247. Melampus, 304, Melanatria, *247, Melania, *246. Melaniade, *246, Melanioides, 240. Melanopsis, 33, 37, *248. Melatoma, *247, Meleagrina, *416. Melia, 191, 195. Meliboea, *334, Melina, 418. Melo, 231. Menestho, 240. Merceneria, 473. Meretriz, 474. Merista, *374, Meroe, *474, Merria, 237. Mesalia, 249. Mesodesma, *484, Metoptoma, *277. Metropolis, 52. Mexico, shells of, 109, Minolia, 265, Miranda, 331. Mitra, 53, *231. Mitrella, 231. Modiola, 11, 33, *421. Modiolarea, *422, Modiolaria, 422, Modiolopsis, *422, Modulus, *252. Molluscoida, 5, 6, Monilea, 264, 514 Monoceros, *223, Monocondylea, *434, Monodaena, 454. Monodonta, *265. Moneecious, 40. Monomyary, 402. Monopleura, *438. Mono-pleuro-branchiata, 312. Monoptigma, *240. Monoptigma, 239. Monoptygma, 313. Monotis, *417. Monstrosities, 37. Montacuta,*460. Montagua, 335. Mopalia, 284. Morio, 225. Morrisia, *367. Morum, 225. Mouretia, 281. Mulinia, 477. Mulleria, 432, *435. Multispiral operc., 208, Munsteria, 182. Murchisonia, *270. Murex, 23, 35, 36, *213. Muricide, *212. Muscular system, 18, 355, 401. Musculium, 461. Mutela, 435. Mya, *489. Myacide, *489. Myacites, *497. Myadora, *499, Myalina, *421. Myatella, 498. Mycetopus, *435. Mycetopus, 435. Myochama, *499. Myoconcha, *471. Myonia, *241. Myoparo, 427. Myophoria, *431. Myopsis, 497. Myrina, *423. Myristica, *217. Mysia, 475. Mylilita, 459. Mytilicardia, 471. Mytilide, *420. Mytilimeria, *422. Mytilomya, 423. Mytilus, 30, 31, 43, *420. Myzxostoma, 308. WNacca, 235. Nacella, *280. Nacreous shells, 29, Nanina, 290. Naranio, 476. Narica, *237. Nassa, *221. Natica, 38, *235. Naticella, 236. Naticide, *235. Naticina, *236. Naticopsis, *235, INDEX. Natural barriers, 53. Natural history provinces, 50—54. Nautilide, *185. Nautiloceras, 194, Nautilus, 161. Nautilus, 55, 185. Navicella, *262. Neera, *491. Neda, *323. Neilo, 429. Neithea, *412. Nematura, *256. Nerinza, *244, 314, Nerinella, *244., Nerita, 38, 55, *260. Neritide, 36, *260. Neritina, 37, *261. Neritoma, *261. Neritopsis, *261. Nervous system, 16. Nets, 139. Neverita, 236. New Zealand shells, 104. Nidamental ribbon, 40. Niphonia, 267, Niso, *240, NNoetia, 427. Nomenclature, 48, Northia 221. Notarchus, *321. Nothoceras, *195. Notoceeli, *174. Notomya, 469. Novaculina, *489. Nucinella, 427. Nucleobranchiata, 340, Nucleus, 205. Nucula, *426. Nucula, *497. Nuculina, *427. Nucunella, 427. Nudibranchiata, *325. Obeliscus, 238. Obolus, *392. Octopoda, *158. Octopodoteuthis, 171. Octopus, 56, *163. Ocythoe, 161, Odoncinetus, 495. Odontidium, 249. Odontostomus, *291. Odostomia, *239. Oleacina, 292. Oligyra, 310. Oliva, 32, 55, *227. Olivancillaria, 227. Olivella, *227, Olivia, 265. Omala, 480. Omalazis, 253. Omalia, 475. Omalonyx, *291. Ommastrephes, *172. Omphalctropis, 307. Oncidiade, *299, Oncidium, *299. Oncidoris, *329. Oncoceras, *193, Ouiscia, #225. Onustus, 254, Onychia, 171. Onychochtton, 284. Ouychoteu:his, *171, Operculata, *305. Operculum, 38, 182, 237. Ophileta, 267. Opis, *470. Opistho-branchia, *311, Opisthophorus, *309. Orbicelia, 389. Orbicula, 358, 386, 388. Orbiculoidea, 388. Orbis, *253. / Orbulites, 187. Oregon, shells of, 109, Ormoceras, *191. Ornati, *198, Orthambonites, 380, Orthide, *379, Orthis, *880. Orthisina, *380. Orthoceras, 38, *190, Orthoceratide, *190. Orthona, 336. Orthonotus, *423. Orthothriz, 385. Oscanius, 322. Osteodesma, 495, Ostrea, 31, *407. Ostreide, *407, Otina, *238. Otolithes, 17. Otopoma, *307. Oviducts, 359. Oviparous repr., 40, Ovulum, 27, *234. Ovum, 41. Owentia, 169. Oxygyrus, *344, Oyster shell, 31. pes; 2. + Pachydomus, *469, Pachylabra, 258. Pachymya, 492. Pachyodon, 434, 470. Pachyotis, 291. Pachyrisma, *470, Pachytes, 414. Pachytoma, 310. Pacyodon, 490. Padollus, 268. Pagodella, 252. Paleoteuthis, 177, 182. Pallia. impression, 20. Pallial line, 404. Pallial sinus, 404. Pailio-branchiata, 354, Pallium, *412. Paludestrina, 254, ) Paiudina, 27,37, *257, 2 Paludinella, 256. Paludinide, *257. Paludomus, *247. Panama shells, 81. Panamic province, 79, Pancreas, 23. Pandora, *499. Pandorina, 498. Panopea, 53, *492, Paphia, 464, 465, 475, 484. Papuan shelis, 103. Papyridea, 453. Parallelopipedum, *425. Parapholas, *506. Parmacella, *297. Parmarion, *297. Parmophorus, *274. Parthenia, 239. Parthenopea, 461. Partula, 291. Pasithea, 240. Patagonian province, 83. Patagonia, shells of, 115. Patella, *278. Patella, 391. Patellide, *278. Patelloidea, 281. Patina, 280. Paucispiral operc., 207. Paxillus, *204, Pearls, 30, 433. Pecchiolia, 467. Pecten, 8, 29, 38, #411. Pectunculina, 426. Pectunculus, *425. Pedalion, 418. Pedicularia, *223, Pedipes, *304. Pedum, *414. Pelagella, ¥332. Pelagia, *354. Peilli-branchiata, 339. Peloris, 407. - Pelta, 290, 323. Pettella, 297. Pen, 173. Pentamerus, *377. Peplidium, 331. Peracle, 352. Periostracum, 33, Periploma, *495. Peristome, 206. Perna, 55, *418. Peronea, 480. Perotis, 170. Persian Gulf shells, 73. Persicula, 232. Persona, 214. Peru, shells of, 113. Peruvian province, 81. Petal conchus, *249. Petricola, 476. Pfeifferia, *290. Phanera-pneumona, 305. Phanerophthalmus, *316. Phanerotinus, *267. Pharella, *488. Pharus, 487. Phasianella, *263. Phasianema, 253. oe la ilippia, 253. Philippine Island snails, 101. Philomycus, 296. INDEX. Philonexis, *165. Phlebenterata, 339. Pholadide, *503. Pholadidea, 35, *505. Pholadomya, 454. Pholadomya, *496. Pholadopsis, 506. Pholas, 28, 102, *504. Phorus, *254. Phos, *221. Phosphorar, 23, 295. Photinula, *265. Phragmoceras, *194. Phragmocone, 39, 173, Phyilidia, *324, Phyllidiade, *324. Phyllirhoe, *338. Phyllirhoide, *338, Phylioda, 480. Phyllodesmium, 335. Physa, 37, *301, Physema, *320. Physiology, 15. Physopsis, *302. Pileolus, *261. Pileopsis, *277. Pilidium, *281. Pinna, 30, 31, *419. Pinnoctopus, *165. Pirena, 36, *248. Pirenella, 243. Pisania, *214. Pisidium, *462. Pisum, 461. Pitonillus, 310. Placenta, *410. Placo-branchus, 339. Placuna, *409, Placunomia, 409. Placunopsis, *410. Plagioptychus, 450, Plagiostoma, 412. Planaxis, #223. Planorbis, *302. Planorbula, 303. Pranulites, 197. Platyceras, 277. Platyodon, 489. Platyschisma, 267. Platystoma, *254. Platystrophia, 380, Plaziphora, 284. Plectambonites, 381. Plectrophorus, 297. Pleiodon, 435. Plesioteuthis, *172. Pleure, 21. Pleurobranchea, *323. Plenrobranchide, *322. Pleurobranchidium, 323. Pleurobranchus, *322. leurodon, 427. Pleuromya, 497. Pleurophorus, *468. Pleurophyllidia, 325. Pleuropus, 336, 349. Pieurorhynchus, 454. Pleurotoma, *228. Pleurotomaria, *270. 515 Plicatula, 55. *414, Plocamophorus, 331. Pneumodermon, 347, *35% Pododesmus, 409. Podopsis, 414, Polia, 487. Polinices, *236, Pollia, 214. Polycera, *330. Polydonta, *304. Polygyra, 289. Polynesian region, 104, Polyphemopsis, 241. Polyphemus, 292. Polytremaria, *270. Pomatias, *307. Pomato-branchia, 312, Pomus, 259. Pontolimaz, 340. Porambonites, *376. Porcellanous shells, 32. Porcellarius, 232. Porcellia, #344. Poromya, 491. Poronia, 459. Portuguese shelis, 64. Posidonia, 417. Posidonomya, *417. Posterobranchea, *323. Potamides, *243. Potamomya, *490. Potamophila, 486. Poterioceras, 193. Priamus, 220, Prisodon, 434. Proctonotus, *337. Productide, *383, Productus, *384. Pronites, 380. Pronoe, 470. Pro-pilidium, 281. Proserpina, 286, *289. Prosobranchiata, *209, Proto, 249. Protocardium, 454, Protozoa, 2. Psammobia, *481. Psammocola, 482, Psammosolen, 488. Psammotea, 480, 482. Psathura, *456. Pseudaxinus, *432. Pseudo-crania, 387. Pseudoliva, *21§. Psiloceros, 330, 335. Psyche, *350. Pteroceras, 35, *211, Pteriza, *417. Pterochilus, 336. Pterocyclos, *308. Pterodonta, *315. Pterodoris, 329. Pteronites, 417. Pteroperna, *416. Pteropoda, 346. Pterotheca, *350. Pterotrachea, 342, Ptychina, 456. Ptychoceras, *201. 516 Ptychomya, 466. Ptygmatis, *244, Pugiunculus, 350. Pullastra, 475. Pulmonifera, 285, Pulvinites, 418. Puncturella, *273. Pupa, 37, *292. Pupillia, *273. Pupina, *309. Pupinella, 309. Purpura, 23, 36, 56, *222. Purpurina, *222. Pusionella, *218. Pycnodonta, 407. Pygope, 363. Pyramidella, *238. Pyramidellide, *238. Pyramis, 239. Pyramis, *265. Pyranus, 469. Pyrazus, *243, Pyreila, 217. Pyrgula, 246. Pyrula, 24, 32, 37, *217. Pythina, *459. Quenstedtia, *481. Quin, 411. Quoyia, 223. Race, 46. Rachis, 21. Radiati, *189. Radiolites, *446. Radius, 234. Radsia, 283. Ranella, 56, *214. Range of marine species, 56 Rangia, 478. Rapana, *217. Raphistoma, *270, Realia, *307. Recluzia, *285. Redonia, *469. Red Sea shells, 73. Renieiia, 416. Representative species, 54, 129. Reproduction of lost parts, 40. Requienia, 346, *439. Respiration, 396. Respiratory system, 25, Retractors, 20, 402. Retzia, *374. Reversed shells, 37. Rhabdoceras, *196. Rhegostcma, *309. Rhinoclavus, *242. Rhinodomus, 221. Rhizochius, 222. Rhizorus, 317. Rhodope, *340. Rhodostoma, 304. Rhomboides, 502. Rhyncholites, 182. Rhynchomya, 495. INDEX. Rhynchonella, 55, 358, *375. Rhynchonellide, *375. Rhynchora, 365. Rhynchoteuthis, 182. Ribeiria, *497. Ricinula, *223. Rimella, 211. Rimula, *274. Rimularia, 275. Ringicula, *222. Ringine'la, 314, Risella, *253. Rissoa, *255. Rissoélla, 256. Rissoina, *256. Rivicola, 301. Rossia, *170. Rostellaria, 35, 55, *212. Rotella, *265. Rothomagenses, *198. Roxania, 316. Rudistes, 440. Runcina, *3823. Rupellaria, 476. Rupicola, 495. Sagda, *289. Sagitta, 342. St. Helena shells, 95. Saliva, 36. Salivary glands, 23. Salpa, 19, 23. Sanguinolaria, 55, *482. Sanguinolaria, 481. Sanguinolites, 468, 498. Sardinian snails, 92. Saxicava, 56, *501, Saxidomus, *473, Scacchia, *458. Scea, 352. Sceurgus, *165, Scalaria, *250. Scaldia, *498. Scalites, *270. Scapha, 230. Scaphander, *318. Scaphaniaia, 182. Scapharca, 424, Scaphella, *230. Scaphites, *200. Scaphula, *227. Scaphula, 424. Scarabus, 304. Schizo-chiton, 284. Schizodesma, 477. Schizodus, 481. Schizostoma, 267. Schizotreta, 388. Sciadephorus, 165. Scintilla, *460. Scissurella, *269. Sconsia, 225. Scrobicularia, *484. Scurria,.281. Scutus, 275. Scyllea, 8, *833. Sedgwickia, *497. Segmentina, 303. Semele, *483, Semicorbis, 467 Sepia, *177. Sepiadee, *176. Sepiola, *169. Sepioteuthis, *168 Septa, 184. Septaria, 506; Septrfer, 421. Seraphs, *212. Serpularia, 266. Serripes, *454, Shell, 28, 204. Sigaretus, *236, Siliqua, 488, Siliquaria, *249. Siliquaria, 488. Simpulopsis, 290. Sinemuria, 470. Sinistral shells, 204, . Sinu-pallialia, *472. Sinus, 20. Sinusigera, 212, 352. Siphon, 26, 155. Siphonal impression, 399, 404, Siphonaria, *281, 305. Siphonaria, 387. Siphonida, *436. Siphonopyge, *321. Siphonostoma, 293. Siphonostomata, *269. Siphonotreta, *390. P Siphonotus, 320. Siphopatellu, 276. Siphuncle, 39, 174, 180, 184. Skenea, *256. Smaragdinella, 316. Smell, 18. Solarium, *253. Solecardia, 460. Solecurtoides, 488. Solecurtus, *488, Solemya, *429. Solen, *486. Solenella, *429. Solenide, *486. Solenomya, 429. Soletellina, 482. Sormetus, *320. South African province,7Q Sowerbya, *478. Spadix, 185. Spanish shells, 64. Spatha, 435. Spawn, 40. Species, 46. Specific areas, 51. Specific centres, 51. Spheera, *457. Spherella, 458. Spherium, 461. Spherulites, 446. Sphenia, *490. Spinigera, *212. Spirigerina, 378. Spiral operculum, 287. Spiratella, 351, Spirazis, 293, INDEX. 517 Spirialis, 347, *351. Tancredia, *457. Tornatellina, #294, Spirifera, *371. Tanysiphon, *477. Tornatina, *315. Spiriferide, *371, Tanystoma, *290. Torquilla, 292. Spiriferina, *372. Taonius, 170. Toxoceras, *200. Spirigera, 373. Tapes, *475. Trans- Atlantic prov., 85. Spiroglyphus, 249. Taste, 18. Trapezium, 467. Spirula, 9, *178. Tebennophorus, 296. Trawling, 139. Spirulide, *178. Tectaria, *252. Tredopsis, *289, Spirulirostra, *177. Tecti-branchiata, *312. Trematis, *389. Spisula, 477. Tectura, 281. Tremoctopus, 159, #164. Sponttylotolus, 387. Tegula, 264. Trevelyana, *331. Spandijlblites, 183. Teinotis, *269. Triboniophorus, *297. Spondylus, 7, 30, 35, 38, 55, Tetlina, 458. Trichites, 31, #420, *413, Teilina, *480. Trichocyclus, *354. Spongaria, 180. Tellinide, *479, Trichotropis, 33, 55, *216. Spongiobranchea, *354, Tellinides, *480. Tricolea, 263. Sporadic species, 51. Tellinodora, 480. Tridacna, 13, 35, 55, *452. — Sportella, 457. Tellinomya, *497. Tridacnide, *451. Stalagmium, 427. Temnocheilus, 189. Tridonta, 464. Steganostoma, 308. Temperature, 39. Triforis, 37, *242, Stenoceras, 197. Tentaculites, *190. Trigona, *474. Stenogyra, *293. Tentaculites, 350. Trigonella, 375, 477, 484. Stenopus, *289. Terebellum, *212., Trigonellites, 182, Stilifer, 9, *241. Terebelium, 248. Trigonia, *430. Stoastoma, *310. Terebra, 55, *220. Trigoniade, *430. Stomatella, *267. Terebralia, *243. Trigonoceras, 194, Stomatia, *268. Terebratella, *365. Trigonocelia, 426. Stomatia, 236. Terebratula, 19, 38, 357, Trigonosemus, *365. Straparollus, 267. 358, *363. Trigonotreta, 371. Strephona, 227. Terebratulide, *363. Trigonulina, 472. Strepsidura, 218. Terebratulina, *364. Triomphalia, 506. Streptaxis, *289. Terebrirostra, 365. Triopa, *330. Streptorhynchus, 380. Teredina, *507. Tritoceras, *192. Striati, *189. Teredo, 35, 341, *506. Triton, 33, 36, 55, 56, *214 Strigilla, 480. Tergipes, *335. Tritonia, *332. Strobilus, 294. Tertiary shells, 130. Tritoniade, *332., Strombide, *210. Testacella, 9, *298. Trivia, *233. Strombus, 31, *210. Tethys, *333. Trochalia, *244, Strophalosia, *385. Tetrabranchiata, *178. Trochatella, 276. Stropheodonta, 381. Tetraplodon, 434. Trochatella, *310, Strophomena, *380. Teudopsis, *168. Trochiscus, 264, Strophostoma, 308. Teuthide, *167. Trochita, *276. Structure of shell, Brachi- Teuthis, 167. Trochoceras, *189. opoda, 360. 7 Texture of shells, 29. Trocholites, 189. Struthiolaria, *246. Thalassides, 470. Trochotoma, *271. Stylina, 241. Thallicera, 259. Trochus, 23, 38, #264, Styliola, 349. Theca, 190, 346, *349. Tropeum, 199. Stylocheilus, *321. Thecacera, *330. Trophon, 55, *218. Stylopsis, *239. Theceurybia, 350. Tropidophora, 307. Styloptygma, *241. Thecidium, 358, *369. Truncatella, 36, #256. Sub-clymenia, 190. Thecosomata, *348. Tuba, 256. Sub-generic area, 52. Thetis, *491. Tubular structure, 52, Sub-spiral operc., 208, Thiara, 246. Tudora, 307. Subula, 220. Thoracoceras, *191. Tugonia, 489. Subulina, 292. Thoracoceras, *195. Tunicata, 5. Succinea, *290. Thracia, *495. Turbinella, *216, Suessia, *372. Thyatira, 456. Turbinellus, 31. Sulco-buccinum, 21°. Thysanoteuthis, *172. Turbinide, *263, Sunetta, 474. Tiara, 231. Turbo, 23, *263. Susaria, *323. Tichogonia, *423. Turbonilla, 239. Suture, 180, 206. Tiedemannia, *351. Turcica, 265. Sycotypus, 217. Tomella, *229. Turrilites, *200. Syncera, *256. Tomigerus, 289. Turris, 228, 231. Syndosmya, *483, Tongue, 287. Turritella, 36, *243 Synonyms, 48, Tonicia, 283. Turritellide, *248, _Syrnola, 238. Torcula, 248. Turtonia, *459. Torinia, *253. Tyleria, *496. Tagelus, 488. Tornatella, *313. Tylodina, *324. Tanalia, 247. Tornatellide, *312. Tylostoma, *314, 518 Tympanotomus, 243. Types, 49. Typhis, 27, *213. Umbo, 29, *398. Umbonal area, 404. Uncini, 21. Uncites, *374. Unguiculate operc., 207. Ongula, 392. Ungulina, *458. Umbilicated shells, 205, Umbrella, *323. Unicardium, *457. Unio, 29, 30, 33, 109, *433. Unio. 497. Unio, distribution, 87. Unionide, *432. Unionites, 468. United States shells, 85. Utriculus, 317. Vaganella, *479, Vagina, 487. Vaginella, *349. Vaginulus, *300, Valvata, *260. Vanicoro, 237. Varices, 13. INDEX. Varieties, 46. Varigera, *314. Varix, 35. Velates, *261. Velietia, 286, *302. Velorita, *463. Velutina, 55, *237, Venericardia, *472, Veneride, *472. Venerupis, *476. Venilia, 337. Venus, 56, *473. Verania, 171. Vermetus, 7, 36, *249. Veronicella, *300, Vertebrata, 1. Verticordia, #472. Vertigo, *293. Vibex, *247. Villiersia, 329. Viquesnelia, *298, Vitrina, *290. Vitrinella, *265. Viviparous reproduction, 40 Viviparus, 257. Vola, 412. Volupia, *473. Voluta, 32, 55, *230. Volutella, 230. Volutide, *229. Volutilithes, *230, Volva, 234. Volvaria, *232. Volvula, *315. Vulsella, 55, *416. Waldheimia, 19, 357, *364, Waltonia, *368. West African province, 69. West American shells, 77. West Indian shells, 84. Woodwardia, 269. Xanthonella, 316. Aenophorus, 254. Xiphoteuthis, *175. Xylophaga, *506. Xylotrya, *507. Yetus, 231. Yoldia, 55, *428, Zaria, 248, Zellania, *368. Zephrina, 337. Zierlania, 231, Zirfea, 505. Zonites, 289, Zua, *292, ' , 7 4 INDEX TO FIGURES. Achatina, 286. Actinoceras, 191. AXgirus, 327. Ammonite, 179, 181, 197, 199 Ampullaria, 258, 259. Ancula, 327. Anodon, 398. Anomia, 402. Aporrhais, 245. Argiope, 368, 369. Argonauta, 161, 162. Ascidia, 6. Astarte, 465. Athyris, 373. Atrypa, 378. Aulosteges, 385. Auricula, 303, 304. Beia, 228. Belemnoteuthis, 176. Biradiolites, 438. Bouchardia, 366. Buccinum, 22, 219. Bulimus, 44, 291. Bulla, 22. Calceola, 383. Camarophoria, 377. Caprinella, 449, 450. Caprotina, 451. Cardium, 454. Carinaria, 202, 343. Cassis, 224. Ceratites, 197. Cerithidea, 209, 243. Chama, 437. Chilinia, 301. Chitonellus, 284, Chonetes, 386. Clymenia, 180, 190. Conocardium, 455. Conularia, 350. Conus, 32, 34. Crania, 387, 388. Crassatella, 466. Crenella, 43. Crepidula, 275. Cyclophorus, 306. Cyclostoma, 307. Cymba, 29, 231. Cyprea, 21, 35, 233. Cypricardia, 468. Cytherea, 20. Dendronotus, 327. Diceras, 439, 440, Diplodonta, 456. Discina, 388, 389. Dolium, 225, 226. Doris, 41. Dredge, 141. Dreissena, 19, 423. Endoceras, 193. Eolis, 17, 203. Fasciolaria, 215, Fissurella, 273. Glycimeris, 494. Gomphoceras, 181. Goniatites, 181, 193, 196. Gryphea, 35, 408. Gyroceras, 194, Hamites, 180, 201. Helix, 4. Hippurites, 444, 445, 446. Huronia, 192. Hyalea, 4, 348. Tanthina, 6, 271. Tsocardia, 467. Kingena, 368. Kraussia, 367. Leptena, 381. Lepton, 18, 460. Limax, 295. Lingula, 391. Littorina, 207, 250, 251. Loligo, 4. Lymnpea, 301. Maclurea, 345. Magas, 366, Merista, 374. Modiola, 403. Monopleura, 438. Morrisia, 366. Mulleria, 436. Murex, 213. Mya, 6, 396, 489. Mytilus, 43. Natica, 235. Nautilus, 180, 186, 188. Navicella, 262. Nerita, 207, 260, 261. Obolus, 392. Octopus, 164. Ormoceras, 191, Orthis, 379. Orthisina, 380. Ostrea, 442. Paludina, 203. Panopeea, 493. Patella, 279. Pearl, 31. Pecten, 17, 401, 411. Pentamerus, 377. Philine, 312, 319. Pholas, 505. Phorus, 254. Phragmoceras, 181 Pinna, 31, 415. Pirena, 248. Pisidium, 460. Planorbis, 303. Productus, 382, 384. Psammobia, 26, 482. Radiolites, 442, 446, 447, 448. Requienia, 439, 440, Retzia, 374. Rhynchonella, 5, 374, 376. Risella, 252. Scissurella, 269. Sepia, 160, 166, Siphonaria, 305. Siphonotreta, 390. Solarium, 253. Solen, 487. Spirifera, 372. Stringocephalus, 370, 371. Strombus, 210, 211. Strophalosia, 385. Strophomena, 381. Struthiolaria, 246. Terebratella, 365. Terebratula, 5, 31, 355, 361, . 3863. Terebratulina, 364. Teredo, 507. Testacella, 298. Thecidium, 369, 370, Thetis, 491. Tornatella, 313. Trawl net, 139. Trichotropis, 217. Tridacna, 452. Trigonellites, 182, Trigonia, 25, 430. Triton, 205, 215. Trivia, 233. Trochus, 21, 38, 207, 264. Uncites, 374 Unio, 399. Velutina, 237. Voluta, 230. Waldheimia, 364, Yoldia, 428, 429, EXPLANATION OF THE PLATES. TuE principal specimens figured were kindly communicated by Mrs. J. E. Gray, Mr. Hugh Cuming, Major W. E. Baker, Mr. Laidlay of Cal- cutta, Mr. Pickering, Sir Charles Lyell, Mr. Sylvanus Hanley, Prof. James Tennant, and Mr. Lovell Reeve, Tho fractions show the number of times (or diameters) the figures are reduced, or magnified. PLATE I. Octopodide. Page 1. Octopus tuberculatus, Bl. 4. Mediterranean ..........,... 163 2. IME whe hea eo ee ede g heat ee esis oes ccenn 156 3. Tremoctopus violaceus, ¢. Chiaje. Messina .......... 159, 164 Teuthide. 4. Sepiola Atlantica, Orb. Atlantic............. é o's «Sa 169 6. Loligo vulgaris, Lam. (gladius). 4. Britain................ 167 7. Onychoteuthis Bartlingii, Le Sueur. 4. Indian Ocean...... 171 8. (Gladitts). Be ince cece acne nob sue ns aun 171 Sepiade. 5. Sepia officinalis, L. 21. Britain ..............essenve ces » 177 Spirulide. 9. Spirula levis, Gray. 4. New Zealand..............s0ce0. 178 a ee a fal il =i —> * ge! Ae Wien se eee me = =A . = a a POA Lp WN yo \ = i \ f SP.Wovdward. 1, EXPLANATION OF THE PLATES. 521 PLATE. EF. Argonautide. Page Argonauta hians, Solander. 3. Chima ....cecssceceesees 162 Teuthide. . Beloteuthis subcostata, Miinst. 4. Upper Lias, Wurtemberg 168 Belemnitide. . Belemnites Puzosianus, Orb. 31. Oxford Clay, Chippenham 173 . Belemnitella mucronata, Sby. 34. Upper Chalk, Norwich .. 175 9. Conoteuthis Dupiniana, Orb. Neocomian, France; Gault, RUPEE M ATS ee Nee nein e's ee...ccatnesce 291 11, 12. —— decollatus, L. 8S. Europe......... siatlal ate stats Pree ren 13, (Partula) faba, Martin. Tahiti .................. 291 14, (4ua) Tubricus, Mill, Britain — 20 .0s23s.+00carde ee 292 15. (_Azeca) tridens, Pulteney. Britain ............. 292 16, Pupa uva, L. sp. Guadaloupe Pees aids oe ved tee oe ed hee 292 li. (Vertigo) Venetzii, Charp. 5. Pliocene, Essex ...... 293 18. Megaspira elatior, Spix sp. % Brazil ..............005 oes De Peetinmlia pucatula, Drap..:\ Kents; ...s00..sccecaavecaevebe 294 20. Cylindrella cylindrus, Chem. sp. %. Jamaica ............ 293 ot oaben perversa, Lisp. “Brita... 6... kee eee 292 22. Achatina variegata, Fab. Col. 3. W. Africa ........... « 292 Beeneewmcn putris. Fi Brita... soe wn és aces asenas ob cme . 290 24, (Omalonyx) unguis, Orb. Paraguay She ro ric cc 291 Limacide. 25. samax maximus, L Britain......... Satie ofsleiebetniagotnene . 295 26. Testacella haliotoides, Fér. 2 Britain ..............05. 298 27. Parmacella (Cryptella) calyculata, Sby. Canaries .......... 297 eee Vere Viraparnaldi. .Cuy, «-Britaim- 2. ..6..ss0ue's sears 290 29 (Daudebardia) brevipes, Drap. 2. Austria ........ 290 Limneide. 30. Limnea stagnalis, L. sp. Britain.............. ae aaioamtes 300 31. (Amphipeplea) glatinosa, Mill. Britain ............ 301 32, Physa fontinalis, Mont. sp. Britaim......20...0.sseecees . 301 33. Ancylus fluviatilis, Lister sp. Britain ............ 000008 302 ee lanorbis-corneis, L..sp.. Britain i... cisseiccasicecmaucees 30% Auriculide. 35. Auricula Judw, L. 3. India ....... hein cinta oa pei ... 304 36. scarabaas, Gynt. tps “@eylon... . 0-0. . sees cece wen 304 37. Conovulus) coffea, L. W. Indies ..... ree w+. 304 38. Vata denticulata, Mont. sp: Britain ....:.. wo. 3805 39. Carychium minimum, Drap. sp. S. Britain...... 305 Cyclostomide. 40. Cyclostoma elegans, Miill. sp. Britain..........00.s00000 306 41. Cyclophorus involvulus, Mill. sp. %. India........... --. 308 42, Pupina bi-caniliculata, Sby. N. Australia ................ 309 43. Helicina Brownii, Gray. 4%. Jamaica..........sesecees en . Acicula fusca, Walker, sp. 4. Britain .............00. 310 532 MANUAL OF THE MOLLUSCA. aan ek &S WH PLATE XIM., The real size of each species is indicated by the accompanying line. Doridide. Page . Doris Johnstoni, A. and H. Brit. (low water) ............ 328 . Goniodoris nodosa, Mont. sp. “ Brit..;...... .sene se eee 330 » Tziopa claviger, Mill..sp. Brit.:.....% ic). isd eee 330 ; Abgiras punctilucens, D’Orb.” Brit....-.......s:sss=ee eee 330 . Polycera quadrilineata, Mill. sp. Europe. (Laminarian zone) 330 . Idalia aspersa, A. and H. Northumberland..............+. 331 Tritoniade. . Tritonia plebeia, Johnst. Brit. (Coralline zone) .......... 332 . Scyllwa pelagica, L. Devon (pelagic) .........cecceeveces 333 . Tethys fimbriata, L. Medit. (pelagic) ........ aaeje ini eee 333 . Dendronotus arborescens, Mull. sp. Brit. ..........06. oe. 304 + Doto ceronata, Gm. sp. Brite. 3.6: 002s dae eae eee 334 . Lomanotus marmoratus, A.and H. Devonshire coast ...... 334 LAolidide. . Molis coronata, Forbes. Brit. (Laminarian zone) ........ 335 . Glaucus Atlanticus, Bl. Gulf-weed banks .......sseeeeee- 300 »' Embletonia pulchra, A. and H. N. Brit.....0. i3:seupeumee 336 . Proctonotus mucroniferus, A.and H. Dublin Bay ........ 337 . Hermea bifida, Mont. Brit. Lit.—Laminarian zone ...... 338 . Alderia modesta, Loven. Brit. Salt-marshes ............ 308 Elysiade. . Hlysia viridis, Mont. sp. Brit. .....000cese00e errr . Acteonia corrugata (head), A.and H. Falmouth .......... 339 » Cenia Cocksn, A. and H.. Malmonth.......:.ssseseee : ae . Limapontia nigra, Johnst. Brit. .........++- cccccccccces O40 * Risin rales Wop 9- Me ey | Iho ay aN Oe sn a ee TWLewry fe. SP Woedward > Nt bee igs = 7) ks rp~ SP Woodward. TW Lowry fe. EXPLANATION OF THE PLATES. 533 PLATE XIV. Opistho-branchiata, Pace 1. Tornatella tornatilis, L. Brit. ....... SA ee oe o vet's ole 2. Cylindrites acutus, Sby. Bath Oolite, Brit................. 313 8. Acteonella Renauxiana, D’Orb. +4. IL. Chalk, France...... 314 4, Cinulia avellana, Brongn. U. Greensand, Brit. .......... 314 5. Tornatina voluta, Quoy sp. 8. I. Guam, Australia........ 315 ampulla, Gre. UNI oe sis n ccs cuss 5'0 se aces »0leee ecu, OG if liye) aucune, T° "dP BTIPpMes. . occas ces eee ene 316 Se tmitaria viridis, Rane. Pitcairn Id... 3.1.0.0 dec ceese cevses 316 eAcere Dullata, Mull Brit.oc.).. se s'vccse siStealate wet e aren ween 316 10. Cylichna cylindracea, Mont. Brit. ...... «acu a aloes canes 317 11. Aplustrum aplustre, L.sp. 3. Mauritius .........c.0ee0. 318 12. Scaphander lignarius, L. sp. 2. Brit.........cseseeee sees 318 eee aperia, Drop. Bribe: oo os ciad 260 cde na wens wo aw uicinne 318 14, Aplysia depilans (hybrida, Sby.). Brit. ........... Ba Ani 320 15. Dolabella scapula, Martyn, sp. 4. Mauritius ............ 321 fe Bepicer Philippi, Krohn... Sicily.s. 366.5 0s cw aeons s 322 17. Pleurobranchus membranaceus, Mont. 2. Brit. .......... 322 18. Umbrella umbellata, Dillw. +4. Mauritius................ 323 Nucleobranchiata. Seaman: cymbium, L. 4. -Medit. .. 0. .-.cessees onedies es 343 20. Cardiapoda placenta, E.and 8. +. Atlantic.............. 343 21. Atlanta Peronii, Les. 22, operc. 23, fry. S. Atlantic ........ 344 24, Oxygyrus Keraudrenii, Rang. 25, operc. 8S. Atlantic ...... 344 26. Bellerophina minuta, Sby. Gault, Brit. .......... = Babies 345 27. Bellerophon bi-carinatus, Lév. 3. Carb. Limestone, Torunay 344 28. ——————- expansus, Sby. 4. U. Silurian, Brit. ........ 345 29. Porcellia Puzosi, Lév. 3. Carb. Limestone, Belgium ...... 344 30. Cyrtolites ornatus, Conrad (cast) 3. lL. Silurian, U. States 346 31. Ecculiomphalus Bucklandi, Portl. 4. Silurian, Tyrone ... 346 Pteropoda. 32. Hyalea tridentata, Gmel. Atlantic—Medit. .............. 348 So @lesdora pyramidata, L. Atlantic. . 5 6.0ccscceesvveseus we 349 Serena aeeniain, Rane. AtAniIC......0.0teccucs coaneten 349 35. Cuvieria columnella, Rang. 8S. Atlantic .............65 349 36. Vaginella depressa, Basterot. 3. Miocene, Bordeaux ...... 349 37. Eurybia Gaudichaudi, Souleyet 8. Pacific (Huxley) ...... 350 38. Psyche globulosa, Rang. Newfoundland.................. 351 39. Cymbulia proboscidea, Peron. Medit. ............eece sees 351 40. Tiedemannia Neapolitana, Chiaje. Medit. ................ 351 41. Limacina antarctica (J. Hooker). 8S. Polar Seas, 63°—46° .. 351 42, Spirialis bulimoides, D’Orb. sp. Atlantic....... db via ad ae 351 43. Cheletropis Huxleyi, Forbes. 5. 8. E. Australia.......... 352 44, Macgillivraia pelaciga, Forbes. 2. C. Byron, E. Australia,. 352 Pee porealis, brug. Arctic Seas. .... 66 oes sewn ateces seve 353 46. Spongio-branchza australis, D’Orb. 3. §. Atlantic, Falk- EINE al) we 6.01 ‘nis: oti acelg cute 'm Aare etna a ot tee ee 354 47. Pneumodermon violaceum, D’Orb. 8. S. Atlantic ........ 353 48. Trichocyclus Dumerilii, Esch. 42. South Sea............ 354 49, Pelagia alba, Q.andG. Amboina...... ee eee re ee 304 50, Cymodocea diaphana, D’Orb. Atlantic..........ceeeeveees 354 yes 534 - MANUAL’ OF THE MOLLUSOA. a) ew be a ee SIO OS —_ SOMO THA NP ob PLATE XV. All, except those marked *, are dorsal views. Terebratulide. . Terebratula maxillata, Sby. 4. Bath Oolite, England, 1 2 —— diphya, F. Col. Alpenkalk, Tyrol ... —_—_——— impressa, Buch. Oxford clay, England... Lyra Meadi, Cumb. 1816. 3. U. Greensand, England . Terebratella Magellanica, Chemn. 4%. Cape Horn ... . Trigonosemus Palissii, Woodw. Chalk, Belgium .......... - Megerlia truncata, Lam. 2. Medit.. .05.« -.5 00 eee eee . Argiope decollata, Chemn, 2. Medit. ............. . Thecidium radians, Brongn. Chalk, Belgium.............. . *——__— hieroglyphicum, Defr. (interior). Chalk, Belgium . Stringocephalus Burtini, Defr. var. 3. Devonian, Europe.. Spiriferide. . Spirifera Walcotti, Sby. 4}. Las, Bath............. . Cyrtia exporrecta, Wahl. U. Silurian, Europe ....... . Athyris lamellosa, Lév. 3. Carb. limes. N. Amer.—Europe . Uncites gryphus, Schl. 4. Devonian, Belgium............ Rhynchonellide. furcillata, Buch. Lias, Europe......... ——_—_—_—_——- spinosa, Schl. 4%. Inf. Oolite, Europe . . Atrypa reticularis, L. sp. 3. Sil-Devon, N. Amer.—Europe 2. Pentamerus Knightii, Sby. 4. U. Silurian ....... “s Orthide. . Orthis rustica, J.Sby. %. U. Silurian, Europe....... Peiophomend rhomboidalis, Wahl. 2. U. Silurian, N. Amer. . Terebratulina caput-serpentis, L. Norway—Medit. .... i Waldheimia australis, Quoy. %. Port Jackson............ é see ee .*Rhynchonella acuta, Sby. 3. lias, Europe ........ ee —LEurope eeevoveveeeseoeer eseeseeeeteees eves eereee eeeeee 5. Leptzena liassina, Bouch. 2. Lias, Hurope ss .sss eet . Calceola sandalina, Lam. 4. Devonian, Europe .......... Productide. Craniade. . Crania Ignabergensis, Retz. Chalk, Sweden ......... Discinide. . Discina lamellosa, Brod. .4. Peru ....ssuss. sace ame Lingulide. . Lingula anatina, Lam. 4. Philippines ............. . Productus horridus, J. Sby. 4. Magn. limestone, Europe.. .*———_——. proboscideus, Vern. 4. Carb. limestone, Belgium . Chonetes striatella, Dalm. U. Silurian, Europe............ SP Woedward I Wlowvry fc IP Woedward. : TW Lowry fe PLATE XVI. Ostreide. Page 1, Ostrea diluviana, Gmelin. 4. Chalk-marl, Brit. .......... 407 2 (Exogyra) conica, Sby. [3 U. Greensand, Wilts .. 408 3. Anomia Achzus, Gray. %.- Kurachee, Scinde ............ 408 4, Placunomia macroschisma, Desh. }. California .......... 409 eeetaenna sella, Gm. sp. 3. Ching,..... 0000. oranats Soe weet nee 409 6 placenta, L. (young). N. Australia .... 1. cas. nee 410 7. Carolia placunoides, Cantr. (hinge). Tertiary, Egypt... .. 410 pemeereremiied. Er 3.. CHMA . eed sccec cs ncscee sess comes 412 9 (Hemi-pecten) Forbesianus, Ad. 2. Sooloo Sea, 14 fms, 412 10. Ciennties)spusio, Pen:* %. Brits «ies oes stistiesees .. 412 11. Lima squamosa, Lam. }. China........ Are cro Gee 412 12. —— (Plagiostoma) cardiiformis, Sby. Bath Oolite, Brit. ..., 412 13. ——-. (Limatula) sub-auriculata, Mont. Brit. .............. 413 14. —— (Limea) strigilata, Brocchi, sp. Pliocene, Italy ...... 413 15. Spondylus princeps, Gmel. 34. Sooloo Sea.............0.. 413 16. (Pedum) spondyloides, Gmel. 2. Red Sea...... 414 iy. at eatula cristata, Lam: §.. W.-Indies . «20.600. - 0% 000 ng 414 Aviculide. 18. Avicula hirundo, L. 4. Medit. ......... a Stas oot ace aye eae 415 19. (Meleagrina) margaritifera, L. sp. 3. Ceylon...... 416 20. ——— (Walleus) vulgaris, Lam. 3. China .............. 416 21. (Vulsella) lingulata, Lam. 4%. Red Sea............ 416 22. Posidonomya Becheri, Bronn. Carb. Hesse, Brit........... 417 23. Pinna squamosa, Lam. 1. Medibie ce. Sipe eee 419 24, Orenatula viridis, Lam. 4. Chinese Seas .........sseeeee 418 EXPLANATION OF THE PLATES, 0389 a,a adductor impressions, p, pedal muscles. g, suspensors of the gills. b, byssal foramen or notch. 536 MANUAL OF THE MOLLUSCA. PLATE XVII. * The figures marked are left valves (interiors). Aviculide. Page 1. Gervillia anceps, Desh. 3. Neocomian, Brit. ..........+. 418 2. Perna ephippium, L. 3. W. Indies .......sssee eee eee . 418 3. Inoceramus sulcatus, Park. %. Gault, Brit. .............. 419 Mytilide. 4, Mytilus smaragdinus,Chemn. 4%. India............. gainuiaeeee 5. Modiola tulipa, Lam. 4.+* Brit,........0+.ccasas=9eneeeee 421 6. pelagica, Forbes. 3. S. Atlantic .............. . 422 if lithophaga, L. $. “Medit. ...... 20.0 ocean 422 §.\Crenella discors; i. Brit. ....5. 25% 0. ose =e eee 422 9. Dreissena polymorpha, Pallas. 3. Brit.............. évane mee Arcade. 10. Arca granosa, L. 3%. Australia..............2+008 éonenbare 424 BIE pexata, Say. 4. 8S. Caroling ......... ..c.eeneeeeeee 424 12. —— (Bysso-arca) Now, L. 3. Medit...............+.000 424 as zebra, Sw. 34. Australia,..... o‘ste'sion ae 424 14. Cucullea concamerata, Martini. 4. India....... 2S agar .. 425 15. Macrodon Hirsonensis, D’Arch. sp. 4. Bath Oolite, Brit... 425 16.*Pectunculus pectiniformis, Lam. 3. India................ 425 17.*Limopsis aurita, Broc. sp. Crag, Suffolk.............es00 426 18. Nucula Cobboldiz, Sby. 4. Crag, Norwich.............. 426 19.*Nuculina miliaris, Desh. #. Eocene, Paris .............. 427 90.* Leda caudata, Donov. Brit.......00 2200 .02+ «saver ee 427 21.*—-( Yoldia) myalis, Couthouy .3. Crag, Norwich ........ 428 22.*Solenella Norrisii, G. Sby. 3. Valparaiso................ 429 23, ————-ornata, G. Sby. sp. 3. Miocene, Patagonia...... 429 Trigoniade. 24.*Trigonia costata, Park. 4. Oolite, Brit. ........s-s0meen 430 25. Myophoria decussata, Mist. sp. Trias, Tyrol ............ 431 26. Verticordia cardiiformis, Wood. = Crag, Suffolk ........ 472 \\\ KXAN \\s \\ ~ ccSSaSeeeeed LETT \P. Wocdward. al al) i | JP Woodward. TW. Lowry te. EXPLANATION OF THE PLATES. 537 PLATE XVIII. * The figures marked are /eft valves. Unionidae, Page 1. Unio littoralis, Drap. 34. Auvergne ............ Sac oniae + 433 2. —— (Monocondylea) Paraguayanus, D’Orb. 4. S. America 434 3. Castalia ambigua, Lam. 4. R. Amazon......12 ......se0s 434 4, Hyria syrmatophora, Gronov. 3. S. Americaft .......... 434 Bae tmdina exotica, Lam. 4... Africa, R. Nile .......6.-.ceee5s 435 6. Mycetopus soleniformis, D’Orb. = ‘%S. America, R. Parana 435 7. Aitheria semilunata, Lam. 4. Senegal .................. 435 Chamide. 8. Chama macrophylla, Chemn. 3. Antilles ................ 437 9, ————_—____—\§_ eft valve .ieeeccceceecceee Net cope sup toe 10. Diceras arietinum, Lam. 4}. Coral Oolite, France ........ 439 Ld. ———__ ——_—$§_~_ eft valve eeeerccccercceeccnccseccscecs 439 12. (Requienia) Lonsdalii, J. Sby. 4. Neocomian, Spain —Brit. ..... sieteDnjarelsie se) ateideatar = ae Siaichelainia oi achaberaualsi clad aan 439 Hippuritide. +3. Caprotina striata, D’Orb. U. Greensand, France .......... 451 Uae I Re TT a ee ee és gents 451 Tridacnide. 15. Tridacna squamosa, Chem. 3. Bombay.................. 452 16. Hippopus maculatus, Lam. 4. N. Australia.............. 452 Cardiade (part). 17. Lithocardium aviculare, Lam. 4. Eocene, Paris.......... 454 Cyprinide (part). 18. Cardilia semi-sulcata, Lam. Amboina........ a ee 469 19 *Megalodon cucullatus, J. Sby. 3. Devonian, Hifel........ 469 { The animal of Hyria has two siphonal orifices. 538 MANUAL OF THE MOLLUSCA, Cardiade. Page 1. Cardium costatum, L. 4. .Chima;......... 222. 453 2. ——— lyratum,G.Sby. }. Madagascar........... + ingle Coes 3. hemicardium, L. 4%. China ...:.:+.;..5eeeeeeee 454 4,* (Adacna) edentulum, Pallas. 3% Caspian ........ 454 5. Conocardium Hibernicum, Sby. 3. Carb. limestone, Kildare 455 Lucinide. 6.*Lucina Pennsylvanica, L. 3. W.Indies........... bee een Tao 7. —-—— (Cryptodon) flexuosa, Mont. Brit................... 456 8. Corbis elegans, Desh. 4. China .........¢.. sete 457 9. Diplodonta lupinus, Broc. sp. Miocene, Turin ,...... cane ae 10. Ungulina oblonga; Daud. 3. Ws Africa .......-.aseemnnee 458 iM, Kellia Taperousii, Desh. California... .:..i\ .< nee 459 12. (Poronia) rubra, Mont. 4. Brit. .............00% ».. 489 13. Montacuta substriata, Mont. 3. Brit. .c.2sceeeeeeeeeee 460 14. Lepton squamosum, Mont. 4. Brit. ...........ceeeeeeee 460 1a, Galeomnia Turtoni, Sby. Brit... 2.2... . 5 «s0ee eee 461 16.*Cyamium antarcticum, Phil 2. Falkland Ids. .......... 458 Cycladide. Py. Cyelas cornea, L.. Ro Tiames:. 2.5.2... ccs cone coeee 461 18. = (Pisidium) amnica, Mull. 8. R. Thames .......... 462 19. Cyrenoides -Dupontil, Joam.:: $. . . . .:0.s:0% 5 « «os diely elena 463 20. Cyrena cyprinoides, Quoy. 3. Ceylon ..........s0-00008 462 21 (Corbicula) consobrina, Caillaud. Alexandrian Canal 462 Cyprinide. 22; Cyprina Islandiea, L. 4. Ns Brit. 2... <0s+.cseseeee space eee 23. Cardinia Listeri, Sby. sp. 43. lLias, Cheltenham .......... 470 24, Opis lunulata, Miller sp. Inf. Oolite, Bridport ............ 470 25. Myoconcha crassa, Sby. }. Inf. Oolite, Dundry .......... 471 PLATE XIX; The figures marked are eft valveu. EELS P ws ee MANIA yaa og Lihnivs x we JAAN TH Lowry fe SL Woedward. EXPLANATION OF THE PLATES. PLATE XX. (All the interiors are right valves.) Cyprinide. 1, Astarte sulcata, Da Costa. Brit. 2. Circe corrugata, Chem. ee edge i oo eeatiaa es Oe 3. Isocardia cor. L. BR Elta oct. 8.1 he 4. Cypricardia obesa, Reeve. ee, os... «us ee 6 6 - Cardita calyculata, L. §. Africa ............... - ——— (Venericardia) ajar, Adans. W. Africa Veneride. seeeerephia, L. W.Tndies......66..2.....0., + ———— (Merve) picta, Schum. %. China 10. —— (Trigona) tripla, L. 3. W. Africa .............. (Grateloupia) irregularis, Baster. %. Miocene, Bor- 2 Iai teielral staal o's a seves= «pee memon ° 9, Psammebia Ferroénsis, Chemn. Brit. .. 00000 «=e smn : 10. —— squamosa, Lam. Borneo «e+ daw cane 5 anteaters 11. Semele reticulata, Chemn. Antilles ,..+-++> Ty si 12. (Cumingia) lamellosa, G. Sby: Peru -.+.sssencuae 13. (Syndosmy@) alba, Wood. Brit.....+++sssers** ions 14. Scrobicularia piperata, Gm. sp. 3. Brit....-- ee » ates 15. Mesodesma glabratum, Lam.” Ceylon ....ss«>+s sauce aa 16. (Donacilla) Chilensis, D’Orb. 3. Peru ..+.-+- 17. — (Anapa) Smithii, Gray. Tasmania ...--eeerers 18. Ervilia nitens, Mont. Antilles ,....-+s00«>+ 1702 sis peamiae = 19. Donax denticulatus, L.. Antilles: .. 0. sss ss vanes AP ert 20 (Iphigenia) Brasiliensis, Lam. 3. Antilles «s.seeeeee 21. Galatea reclusa, Born sp. 1, BR. Nile....:- 5 0 ie ene aoe —_— Tancredia extensa, Lycett. 4 Oolite, Brit. .ssseeeeterers Dl ay \ase—o> WO WRN 7 —- x be! Jj, ae Livre MINE RN a Yn ~ SP. Woodward. cio I aire IWihowry Je- SP. Woodward. EXPLANATION OF THE PLATES. PLATE XXII. * The figures marked are /eft valves (interiors). 541 Tellinide. Page {. Sanguinolaria livida, Lam. 4. N, Australia.........:.... 488 2. gipher,, Chemmn: "922 Indias 6.5.0) iexd eee 483 3, orbiculata, Wood. 3% Penang ............ 483 Solenide. mn eneTePLC He in - TDETE. . ose aa db ala 2 @ aoe es 486 5. Cultellus lacteus, Spengl. 4. Tranquebar,............... 487 6. (Cerati-solen) legumen, L. %. Brit............5.. 488 fp (Machera) politus, Wood. 2. India ............ 488 Saoelecurtus siticilatus, L. %. W. Africa. .....c..ccccccnes 488 9. ———— Caribeus, Lam. %. U. States...............0.. 488 10. -—-—— (Novaculina) Gangeticus, Bens. Calcutta ........ 489 Myacide. Po. faces byabnaSbyssp.. ck. CHINA ds cal od Seesisa danwnehe 491 12. Panopza Americana, Conrad. 4. Miocene, Maryland . 492 13.*Saxicava rugosa, L. 3. Brit——Kamtschatka.............. 501 14. Glycimeris siliqua,Chemn. %. Arctic America,,.....,.... 498 Anatinide. 15.*Pholadomya candida, Sby. 4. W. Indies................ 496 1G, Goniomya literata, Sby. 4. Oolite, Brit. ...........ec0cs 497 Pe molemya‘topata, Polisp. $. Mediti. 00s. ccc eescte recess 429 542 MANUAL OF THE MOLLUSCa. PLATE XXIII. # The interiors marked are /eft valves. Myacide. Page 1.*Mya truncata, L. 3. Brit. 0.0... sees ee eeeees ski ie ae 489 9. Corbula sulcata, Lam. W. Africa........seeeeeeeee cece 490 3. — (Potamomya) labiata, Maton sp. 3. Buenos Ayres 490 4, (Sphenia) Binghami, Turt. Brit.......++++-eeeee es 490 5. Newra cuspidata, Olivi. Brit...... 0.2: s+ sees ee eeees ve waa gene 6. Anatinella candida, Chemn. 3. Ceylon.......... Reo oe 479 Anatinide. 7. Anatina subrostrata, Lam. 3. India .........++. fiat 495 8. Cochlodesma praetenue, Mont. Brit........-eseeeee erence 496 9, Thracia pubescens, Pult. 3. Brit. .........+eeeeeeeeeeee 496 10.*Lyonsia Norvegica, Chemn. sp. 2, Brit. ..«s -. geen 498 11, Pandora rostrata, Lam. 3 ‘#7 O7NSCY.. ee eee eee eee cece 499 12. Myodora brevis, Stutch. New South Wales’ occa. PEA eh at 499 13. Myochama anomioides, Stutch. New South Wales ........ 499 14. Chamostrea albida, Lam. sp. 3. New South Wales ...... 500 Gastrochenide. 15. Gastrocheena modiolina, Lam. Galway ...seeeeeeeee eres 501 lida. sp. siphonal orifices, in U. Greensand, Haldon, DevOUSHITE 6... cis pow sa acetals wees > 6 Se oie ee 501 16. mumia, Spengl. 2. India. 2. .sSore a + aaiehinete 501 17. Clavagella bacillaris, Desh. 3. Pliocene, Sicily, 22:2 eeeee 502 18. Aspergillum vaginiferum, Lam. 3. Red Sea...,: ss. asec 503 Pholadide. 19, Pholas Bakeri, Desh. 3. India ......++-sseeees smi teiy ete 504 20. (Pholadidea) papyracea, Solr. %.. Brits so... serene 503, 21. (Martesia) striata, L. W. Indies ........ 3. STREPTOCERAS, Billings, 1865. Etymology, streptos, curved, and ceras. Shell having the form of Onoceras, but with a trilobed aperture like Phragmoceras. Distribution, 2 species. Middle Silurian. Canada. LirvirEs, Breynius.t Type, Li. lituus, Hisinger. Shell discoidal, whorls (2—5) close or separate; last chamber produced in a straight, or nearly straight line, sometimes : slightly curved, in a direction contrary to that of the spire; — lateral margins of the aperture extended and curved towards © the interior of the shell; the aperture contracted thus presents two distinct orifices, the smaller corresponding to the convex or ventral side, the larger to the concave or dorsal side of the shell. L. lituus is the only species in which the aperture has been observed. 28 species from the Middle and Upper ? Silurian rocks of Europe and North America, belong here or to allied genera. Sub-genus :—OPHIDIOCERAS, Barrande, 1867. Synonym, Ophioceras, Barrande, 1865. Hiymology, ophiodes, shaped like a serpent, and ceras. Type, O. Nakholmensis, Kjerulf (Lituites). Shell with the produced portion very short or wanting. The shells of the Bohemian species are keeled on the conyex side. Distribution, 7 species. Middle Silurian; Norway (1). Upper Silurian, Bohemia (6). , cinta ateanama Lituuncuuvs, Barrande, 1867. Shell as in Lituites, but with a simple aperture. No species have been yet: observed. Sub-genus :—DIscocERAS, Barrande, 1867. Hiymology, diskos, a quoit, and ceras. Type, D. antiquissimus, Hichwald (Litwites). * See p. 194, ¢ See p. 189. / CEF HALOPODA, Shell with the produced portion very short or wanting. This sub-genus bears the same relation to Litwunculus (the existence of which is supposed) that Ophidioceras does to Lituites. Distribution, 3 species. Middle Silurian. Russia, Germany, Norway. HERCOCERAS, Barrande, 1867. Etymology, erkos, a wall, and ceras. Type, H. mirum, Bar. Middle Silurian, Bohemia. Shell usually involute, as in Nautilus, rarely with separated whorls as in Gyroceras, or with a spire as in T'rochoceras. Body- chamber with a diaphragm perpendicular to the axis of the shell, the concavity of which is opposed to that of the last septum. This disposition throws the aperture on the convex side of the shell, which is deeply excavated. Siphuncle dorsal, cylindrical, inflated between the chambers, separated from the shell. Nautilus subtuberculatus, Sandberger, from the Devonian of Nassau, may belong to this genus. BATHMOCERAS, Barrande, 1867. Etymology, in allusion to the imbricated arrangement of the partitions. Type, B. complexum, Barr. (Orthoceras). Shell haying the general appearance of Orthoceras. Part of the body-chamber occupied by a series of imbricating plates, which decrease in horizontal extension from below upwards. Siphuncle composed of a series of superimposed funnel-shaped tubes, the narrow end directed towards the aperture of the shell. Distribution, 2 species. Middle Silurian, Bohemia. AULACOCERAS, Hauer, 1860. Htymology, aulax, a furrow, and ceras. Type, A. sulcatum, Hauer, Fig. 7. Shell straight, like Orthoceras ; corrugated, with two deep lateral furrows; siphon simple, & . very small, marginal and dorsal, situated & & between the longitudinal sulci. The test & increases rapidly in thickness towards the ¥f, apex of the shell. The genus is a transition form between Fig. 7. Transverse sec the Nautilide and the Belemnitide. kintit GE tadacidieae teat Distribution, 4 species. Upper Trias, catum. Austria. R3 9 MANUAL OF THE MOLLUSCA. [FamILy GONIATIDZ. Barrande. ] Shell involute or straight; septa concave in their median section ; sutures usually with angular lobes ; septai tubes coni- cal, more or less prolonged, but always directed backwards. Siphuncle cylindrical, of small diameter, always marginal ; siphonal investment not persistent; convexo-ventral margin of the aperture sloped, lines of growth and ornamentation of the shell with a corresponding sinuosity. The genera enumerated in this family are Goniatites, Clymenia, and Bactrites. Dr. Woodward includes the Goniatites and the Bactrites (pp. 196, 197) with the Ammonitide and the Cly- menia with the Nautilidee (p. 190). FAMILY ITI.—AMMONITID&. Shell various ; septa convex in their median section ; sutures always lobed, ramified, or denticuleted ; septal tube cylindrical _ and always directed forwards. Siphuncle cylindroid of small diameter, always marginal; siphonal investment more or less solid and persistent. Convexo-yentral ? margin of the aperture more or less prolonged, which determines a similar convexity in the lines of growth and ornamentation of the test; there are rare specific exceptions. Division I..—SUTURES LOBED OR DENTICULATED AT THE BASE. 1. RHABDOCERAS (see p. 196). 2. Bacurina, D’Orbigny, 1850. Example, B. Rouyana, D’Orb. Neocomian, France. Shell like Baculites, but its lobes and saddles are not foliated, there being between these forms a similar distinction to that between Ceratites and Ammonites. B. acuarius, Schlotheim, is from the Oxfordian strata of Gammelshausen in Wurtemberg. 3. COCHLOCERAS, Hauer, 1860. Etymology, cochlos, a snail-shell, and ceras. Type, C. Fischeri, Hauer, Fig. 8. Shell resembling that of Turrilites, with the sutural lobes simple, as in Rhabdoceras and Clydonites. _ 10 CEPHALOPODA. Distribution, 3 species. Upper Triassic strata of Hallstadt, Austria. Fig. 8. Shell and sutural lobes of Cochloceras Fischeri. 4, CHORISTOCERAS, Hauer, 1865. Type, OC. Marshu, Hauer. Shell somewhat similar in form to Crioceras, with the lobulag ornamentation characteristic of Ceratites. Distribution, 4 species. Upper Trias, Austria. 5. CLYDONITES, Hauer, 1860. — ! My SN cM . Shell and sutural lobes of C. Fig. 9. Shell of Clydonites costatus, Hau. Figs. 10a, 10b delphinocephalus, Hau. Etymology, kludon, the surge, with the usual termination. Examples, Goniatites Eryx, Miinst; Ammonites delphino- cephalus, Hauer. Figs. 9, 10. Shell, discoidal; sutures lobed; lobes entire, not crenulated as in Ceratttes. Distribution, Upper Triassic strata, Hallstadt and St. Cassian, in the Austrian Alps ; North-western Himalayas; 21 species. Upper Cretaceous, 2 species described as Ceratites by D’Orbigny. | FE ewe MANUAL OF THE MOLLUSCA. 6. CERATITES (see p. 197). Division II.—SuUTURES FOLIATED Including the genera Ammonites (p. 197), Toroceras, Ancylo- ceras,* Scaphites, Helicoceras, and Twurrilites (p. 200), Hamites, Ptychoceras, and Baculites (p. 201), and the following. ANISOCERAS (see p. 200), Pictet, 1854. Etymology, anisos, unequal; and ceras. Example, Hamites armatus, Sowerby. Shell at first growing in an open helicoid spire, afterwards more or less prolonged and reflected; ornamented by trans- verse ribs. Sutures of septa divided into 5 lobes and 5 saddles, all bipartite; the lateral saddles are the largest. Fossil, 12 species. Gault—Upper Green Sand, Europe. COre- taceous, India. 1 species, Jurassic. North-west Himalayas. Species of Helioceres founded on helicoid portions of shells may belong to this genus. HAMULINA (see p. 201), D’Orbigny, 1852. Example, H. dissimilis, D’Orb. Shell conical prolonged, haying a portion of the body chamber reflected, but not touching the other portion; section of the — shell round or laterally compressed; sutures of the septa divided into six lobes, and as many saddles. Hamulina differs from Hamites in being only once reflected nstead of twice, and from Pétychoceras in having the reflected portion of the shell separate from the other, not close together. Distribution, 15 species. Neocomian, France. Ootatoor group (= P Gault), India. , PELTARION, Deslongchamps, 1859. Founded on the mandibular armature of tetrabranchiate cephalopods . * Many of the forms considered to belong to Crioceras have been ascertained by M. Astier to be only more or less incomplete individuals of species belonging te Ancyloceras. That Crioceras must merge into Ancyloceras appears inevitable. GASTEROPODA. Example, P. bilobatum. Upper Lias, Normandy. Fig. 11. Caleareous plates nearly circular or transversely oval ; ante- rior border rounded, posterior produced and truncated ; concave above and flattened below; the two faces have one-half smooth and the other concentrically striated in an inyerse direction to each other. Fossil, 3 or 4 species. Up. Lias— Cor. Rag. England; Normandy ; Wurtemberg. CLASS. II.—GASTEROPODA. ORDER I.—PROSOBRANCHIATA. Famity II.—MuRIcipz (see p. 212, &c.). The genera included in this family are :— MurREX, TYPHIS, PISANIA, TROPHON, FASCIOLARIA, TURBI< NELLA (Cynodonta, Latirus, Lagena), Fusus (Clavella, Chryso- domus, Pusionella, Tritonidea), EULGUR, COMINELLA, MyRIs- TICA, and LACHESIS ANnAcHis, H. and A. Adams. Type, Columbella scalarina, Sowerby. Shell like Columbella; operculum elongated, unguiform, nucleus terminal, having close analogies with Pisania. Distribution, 27 species. Tropical America. PTYCHATRACTUS, Stimpson, 1865. Etymology, ptych, a fold; atractus, a spindle. Type, Fasciolaria ligata, Mighels and Adams, Deep water; United States. 13 MANUAL OF THE MOLLUSCA. Shell fusiform, spirally striated ; aperture with a rather long | canal; columella plicated as in Faselolardr. operculum like — that of Chrysodomus. Lingual dentition, resembles that of the— Purpuride, 1:1°1. Rhachidian tooth, deeply arched, with three denticles; lateral teeth versatile, elongated, simple, hook- shaped, base swollen. Buccinopsis, Jeffreys, 1859. < Etymology, having the aspect of Buccinum. Synonym, Liomesus, Stimpson, 1865. Type, Buccinum Dalei, J. Sowerby, Britain. Shell oval, spirally striated; epidermis filmy; spire short, obtuse; outer lip smooth within; canal short and open; oper- culum triangular; nucleus placed on the inner base of the aperture. The lingual dentition makes an approach to Mangelia, and consists of a single plain and slightly curved tooth on each side of a thin non-denticulated plate. The egg cases of Buccinopsis are separate. Distribution, 3species. German Ocean, North Atlantic, Spitz- bergen, Behring’s Straits. Fossil. B. Dalei occurs in the Red, Antwerp, and Coralline — Crags. England, Belgium. is Cheletropis is the fry of species belonging to the Muricide. Adamsia, Dunker, resembles a sculptured Oominella without the sutural construction of the whorls. 2 species. Australia. Faminty IJ1.—Buccrnipz.* The enumerated genera are :— : BuccinuM, PsEvuDOLIVA, BuLLIA, Epurna, PHos, NAssa (Cyllene, Northia, Cyclonassa), CoLUMBELLA, TRUNCARIA, and — TEREBRA (Myurella), SUBULA (Huryta). TRUNCARIA, A. Adams and Reeve, 1848. Synonym, Buccinopsis, Deshayes. Type, T. filosa (Buccinum). Adams and Reeve. China. Shell oval, oblong; spire elongated; apex acute, often chan- nelled at the suture; aperture oblong, dilated in fa angu- lated, sometimes wih a small canal peal outer lip simple or bordered; columella concave, abruptly truncated, and shorter than the right lip. * See p. 218, &c. 14 es eee GASTEROPODA. Species of this genus are Buccinwms with a truncated colu< meila. Distribution, 5 species. China, Central Ameria, Vigo Bay. Fossil, 3 species. Hocene. Paris basin. [FAMILY PURPURIDZ | Is composed of the following genera :— PuRPURA, including Monoceros (of sectional yalue)* and the sub-genera :— Concholepas, Cuma, Rapana (see p. 217, under Pyrula), Pinaxia, Adams. Topas, H. and A. Adams, 18538. Shell bucciniform, with a small canal in the posterior angle of the aperture. Fossil, 3 species. Eocene. Paris. Vitularia, Swainson, 1840. Y. salebrosa. South and Central America. Shell with irregular varices ; operculum as in Purpura. Nitidellz, Swainson. Shell as Cylindra; spire sometimes decollated; lip continuous or crenated; operculum elongate; nucleus lateral. RIcINULA, HARPA, RHIZOCHCHILUS (Coralliophila, Adams), and MAGILUS, with the Sub-genus Leptoconchus, Riippell. Shell similar to that of Magilus; young shell only with an operculum. [FAMILY CASSIDZ. ] The genera referred to this family are :— RANELLA (p. 214), TRITON (p. 214), PYRULA (p. 217), Cassis (p. 224), ONISCIA (p. 225), CASSIDARIA (p. 225), DoxLium (Malea) (p. 226), and NASSARIA, Pfeiffer. Animal analogous with that of Ranella, as regards the length of the tentacles, position of the eyes, smallness of the head, and by the form of the operculum, but is provided with a long ‘ branchial siphon. Shell sub-canaculated in front, and deeply notched. [Famity OLrvipz] Includes OntvaA (Olivella, Scaphula, Agaronia), ANCILLARIA (Monoptygma, Lea).t * See p. 223, t See p. 227. 15 MANUAL OF THE MOLLUSOA. 7 [FAMILY VOLUTIDZ]| Contains COoLUMBELLINA (p. 227), Mirra (Imbricaria, _ Strigatelia, and IHyalina) (p. 231), VoLUTA ( Volutilithes, Scaphella, : Volutomitra, and Melo) (p. 230), CymBA (p. 231), MARGINELLA — (p. 232), VoLVARIA (p. 232), and a 4 ie = Lyri, Gray, 1847. Synonyms, Harpella, Gray; Eneeta, Gray. Types, Li. deliciosa, Montf.; L. harpa, Barnes. 4 Shell ovate oblong, See thick, sometimes longitudi-— nally costated; aperture subovate, with a large number of © columellar plaits, the two anterior of these being the strongest ; — posterior portion of the inner lip provided with a large number © of short cross-plaits. Operculum ovate-elongate, thin ; corneous — nucleus at first nearly central, at a more advanced age sub-~ apical. a Distribution, 14 species. Pacific Ocean, America, Madagascar, ~ Australia, Japan, New Caledonia, Antilles. Fossil, 3 species. Cretaceous. India. The species in the ~ Tertiary strata have not been distinguished from Voluta. . Cysriscus, Stimpson, 1865. fr Type, C. capensis, Cape of Good Hope. 4 Shell resembling that of Marginella; small, thin, ovate, inflated, smooth, ‘and polished ; aperture narrow, columella — plaited. Animal with an elongated foot, truncated in front; head ob-— long, depressed ; tentacles triangular, flattened, and horizontal; — eyes at the lateral margins of the head, at the bases of the ten- : tacles. Lingual dentition, 0:1:0, resembling the rhachidian ~ teeth of Afurew, thick and strong, with seven unequal conical ~ denticles. % [FAMILY CYPRZIDAE] includes Hrato, Oyprma (Oyprovula, Luponia, and Trivia), OvULA (Volva and Radius), PACHYBATHRON, PEDIOULARIA, and — DENTIORA, Pease, 1862. Type, D. rubida, Sandwich Islands. . Shell differs from that of Pedicularia in the Set Sens “a columella, compressed, and toothed. ee i 16 ie GASTEROPODA. FAMILty ConIDz Contains Convs (Conarbis), DrsApHus, PLEUROTOMA (Driilia, Bela, Clionella, Daphnella), CLAVATULA (Tomella), MANGELIA (Clathurella), LACHESIS, CITHARA, and BorsontA, Bellardi, 1839. Synonym, Cordieria, Ronault, 1848. Shell like Plewrotoma, with oblique folds on the thick colu- mella, and thus establishes a passage between Pleurotoma and Turbinella. Distribution, 4 species. East Indies. Fossil, 23 species. Hocene—. France, Italy, England, United States. GosAVIA, Stoliczka, 1865. Type, Voluta squamosa, Zekeli. Shell similar to that of Conus ; aperture narrow, elongated ; base emarginate; outer lips notched near the posterior suture ; columella lip plicated, the anterior plaits being always the strongest. Fossil, 8 species. Cretaceous. — Eocene? Gosau; India. [FamiIny NATICIDz. | The genera are— NATICA, containing as sub-genera WNaticospis, Neverita, Lunatia, Globulus, Globularia, Polinices, Cernina, and Euspira (Agassiz), Morris and Lycett, 1850. Spire more or less elevated ; whorls few, distinct, angulated, or carinated. Fossil, 6 species. Inferior Oolite—. Forest Marble. Eng- land. ‘‘ Huspira presents considerable affinities to the Paleozoic genus, Scalites (Hall), in the lines of growth having the appear- ance of a slight fissure, where the angle occurs in the yolution.” (Mor. and Lyc.) SIGARETUS (and sub-genus Naticina). LAMELLARIA (Oncidiopsis‘and Marsenia), VELUTINA. AMAURA. Type, A. candida, Moller. Greenland. 17 MANUAL OF THE MOLLUSCA. ‘Animal allied to Natica ; foot small, compact without any — posterior lobe ; the front lobe deeply sinuated; eyes subcuta- neous, situated at the internal base of the lobe; operculum _ terminal, few-whorled, horny, thin. ‘Shell ovate, imperforate, spire small, produced; mouth — reversed, pear-shaped, about half the length of the shell.” (Moller ) Fossiz, species. Cretaceous. Germany, Britain. DESHAYESIA, Raulin, 1844 (see p. 236). Dedicated to M. Deshayes, author of “‘ Description des Ani- — maux sans Vertébres dans le bassin de Paris,” &c. . Synonym, Naticella, Grateloup (non Miinster). Type, D. Parisiensis, Raulin. : Shell subglobose, thick, umbilicated; spire short; aperture — entire, semicircular, oblique ; columella oblique ; callosity den. ~ ticulated; umbilicus covered by the callosity; right lip acute, smooth internally. F This genus presents a very remarkable combination of the — characters of Natica and Nerita, and appears to establish a pas=- sage between these two genera, types of distinct families. r Distribution, 2 species. Oligocene and Miocene. Paris and — Bordeaux Basins PrycHosTomMA, Laube. Fossil, 3 species. St. Cassian. [FamiIty CANCELLARIDZ. ] The genera are— CANCELLARIA (Admete, p. 216), TRIcHOTROPIS (p. 216), — ? CERITHIOPSIS (p. 242), P SEPARATISTA, and PurPurina,* D’Orbigny, 1850 (p. 222). Type, Purpurina Bellona, D’Orbigny, Fig. 12. * This genus has been the subject of careful research and revision by Messrs. Eugene Deslongchamps and Piette ; and I think it advisable to replace the characters of this group, given in p. 222 of the Manual, by those emended by the authors above mentioned, 18 GASTEROPODA. Shell oval, elongated, ventricose, thick ; whorls rounded or rendered angular by the upper portion being channelled; last whor! much developed. Ornamentation usually of Fes large longitudinal ribs, crossed by numerous Ayes strie ; aperture large in the young state, GRR slightly notched in front ; columella rounded ; umbilical groove deep, narrow, but well de- fined. Fossil, 8 species. Inferior Oolite—Kelloway Rock. England, France, Germany. Fig. 12 Parpurina Bellona. TORELLIA (Loven), Jeffreys, 1867. Dedicated to Dr. Otto Torell, of Norway. Type, T. vestita, Jeffreys. Shetland and Norway. Animal with the produced lips and lingual dentition of Capulus. Shell globose, covered with a velvety epidermis; spire very short ; apex depressed ; aperture roundish ; pillar with a blunt tubercle at its base; groove internal, scarcely perceptible ; operculum lke that of Z'richotropis. [FAMILY NERITOPSIDZ. | Genera :—NERITOPSIS and NARICA with WNaticella as a sub- genus (see p. 261). [FAMILY PYRAMIDELLIDZ.*] The following genera and sub-genera are additional :— PYRAMIDELLA. Sub-genus Chrysallida, P. Carpenter, 1857, Shell pupiform; peristone continuous; edge of lip thin; columella-plait distinct, though hidden; operculum in the typical species radiately corrugated. Distribution, 25 species. E. and W. Indies, Japan, Mazatlan. Opostomi1A. Some of the Mazatlan species have the peri- stone continuous. Sub-genera :—Auriculina, Gray. Shell having the general aspect of Odostomia, but presenting no vestige of a plait. Mazatlan, 3 species. Fossil, 4 species. Tertiary. United States. Parthenia, Lowe (Hbalia, Adams). Surface sculptured ; columella plaited. Distribution, 10 species. Mazatlan, Japan. * See p, 238. 19 MANUAL OF THE MOLLUSCA. ScALENOSTOMA, Deshayes, 1863. Type, 8. carinatum, Isle of Bourbon. ; Shell in form allied to Pyramidella and Niso, turriculated, — white, imperforate; columella not plicated; opening subtri- angular, slightly bent in the direction of its length; margin” simple, notched near the suture. 4 CHEMNITZIA. Sub-genera :—Dunkeria, P. Carpenter (dedi- — cated to Professor W. Dunker). Aperture as in Chemnitzia,~ but the whorls rounded as in Aclis; whorls cancellated. Distribution, 7 species. Mazatlan, Japan. Pseudomelania, Pictet and Campiche, 1864. Htymology, Se false, and Melania, a generic name. . Shell turriculated, spire acute, test thick, imperforate, without ornamentation. Aperture oval, rounded in front, more — er less angulated behind; columella thick, conforming to the — general curvature of the aperture; lip simple. : Distribution. Trias—Chalk. Europe, South Africa. The cretaceous species are 14 in number. EurmaA. Sub-genus :—Leiostraca, H. and A. Adams (Balcis, ~ Leach). Shell with a slight varix on each side of the spire. Distribution, 8 species. Mazatlan, Taboga. ActcuLiIna, Deshayes, 1864. Shell small, aciculated; apex laterally inclined; whorl numerous, convex, smooth; aperture entire, small, subqua- — drangular; columella cionicht, narrow, cylindrical, ae simple, — Distribution, 6 species. Eocene. Paris basin. MATHILDA, Semper, 1865. Shell turriculated, apex revolute, abruptly turned from left to — right ; whorls in the typical species transversely cingulated and reticulated, longitudinally striated; aperture entire, subro- tund, base sometimes subeffuse; lip acute; columella smooth, not plicated. : Distribution. The type Turritella quadricarinatus, Brocchi, is living in the Mediterranean, and is fossil in the Crag of Anvers, and at Bologna. Fossil, 13 species. Hocene—. Europe, United States. SoLEeniscus, Meek and Worthen, 1860. Etymology, soleniskos, a little channel or gutter. 20 GASTEROPODA. Type, 8. typicus. Upper Coal Measures. Springfield, Illinois. Shell fusiform, smooth, body whorls contracted below into a distinct straight canal, with an oblique plait on the columella. Agrees with Macrocheilus in its smooth surface and columella fold, but differs in its fusiform outline, narrow aperture, and distinct canal. In its general appearance resembles Fasciolaria, but has only one instead of two or three columella folds, and is destitute of ornamentation, and its outer lip is smooth within. EUCHRYSALIS, Lambe. Fossil, 6 species. St. Cassian, Austria. [FAMILY STILIFERIDZ. | The genera are :-— STILIFER.—Dr. Fischer supposes that Stilifer, though living like a parasite on the tegumentary system of the echinoderms or their appendages, does not feed on their substance, as has been supposed. Mr. Gwyn Jeffreys’s impression is that it feeds on the excretions of the echinoderms. STYLIFERINA, Adams. Shell imperforated, ovateconical, thin, smooth; whorls many, produced in a styliform spire; nucleus sinistral; aperture sub- quadrate; lip simple, straight. Distribution, 2 species. Japan. M. Freyer, of Trieste, is of opinion that Entoconcha (E. murabilis), which is parasitic on Synapta digitata, is the embryonic condition of a species of Natica. Famity IIIl.—CERITHIADZ.* Includes CERITHIUM (Lhinoclavis and Bittiwm), TRrIFoRIS, © Potamipres (Vicarya, Cerithidea, Terebralia, Pyrazus, and Lampania), NERIN@A, and the following additional genera and sub-genera :— CERITHIUM.—Sub-genus. Sandbergeria, Bosquet, 1860. Dedicated to Professor Sandberger. Type, Cerithium cancel- lata, Nyst. sp. Shell short, like Cerithiwm, canal terminal, very broad, and short. M. Bosquet describes the type as having an operculum as in Stenothyra; itis very questionable as to whether the operculum belonged to the shell, * See p. 242, &c. 21 MANUAL OF THE MOLLUSCA. Distribution, 29 species. Cretaceous; India. Eocene. France. Netherlands. ~ Evustoma, Piette, 1855. Type, E. tuberculosa, Piette. Shell in the young state resembling Cerithium ; in the adult the margins of the aperture are much expanded and posteriorly united by an indistinct canal; canal elongated. Fossil, 2 species. Great Oolite. Ardennes. EXELISSA, Piette, 1861. Etymology, ~elisso, to unfold. Synonym, Kalvertia, Lycett, 1863. Type, Cerithium strangulatum, D’Archiac. ; Shell small, elongated, subcylindrical, somewhat pupzeform, ~ many whorled, perpendicularly costated, tuberculated or spined ; ~ last whorl cylindrical, contracted at the base, with a tendency — to separate from the axis; aperture Srpieaiae entire, the lips — elevated, produced, and shghtly thickened; columella solid. — Fossil, 14 species. Mid. Lias—Kimmeridge Clay. England ~ and France. The shelly freestone of the Inferior Oolite, Glou-— cestershire, contains some undescribed species. Cretaceous, 1 ~ sp. ? India. | FIBULA, Piette, 1857. : Example, Turritella Roissyi, D’Archiac. ; Shell elongated, columella straight, with a rudimentary groove near the base; outer lip arched, slightly notched at the suture; base of the aperture forming a slight canal, or rounded and entire, depending upon the exact period of growth at which the animal perished. The species of this genus possess characters intermediate and — approximating them to Turritella and to Cerithium. Fossil, 21 species. Triassic—Cretaceous. Europe, India. CRYPTOPLOCUS, Pictet and Campiche, 1854. Etymology, cryptos, hidden ; ploce, a plait. : Example, Nerinzea monilifera, D’Orb. Shell, as in Nerincea, without columella and labial plaits; one plait on the posterior face of the aperture, a disposition very analogous to that in some Cerithiwms, such as C. noduloswm, — aperture rounded, not channeled in front; umbilicated or im ~ perforate. 22 GASTEROPODA. Distribution, 7 species. Jurassic and Cretaceous. France, Switzerland, Germany. PLANAXIS. M. Deshayes places this genus in Littorinide, but Dr. Macdonald states that it is anatomically closely related to Cerithium, the lingual teeth are similar, and that the audi- tory sacs contain spherical otoliths. QuoyiA, Deshayes, 1830. Dedicated to the celebrated naturalist to the Astrolabe. Synonyms, Fissilabria, Brown ; Leucostoma, Swainson. Shell solid, elongated, conical, apex decollated; whorls flat, the body whorl sub-angular at the base; aperture small, semi- lunar, produced in front; columella thick, curved, truncated anteriorly, with a spiral fold posteriorly, operculum horny, paucispiral, nucleus lateral. Distribution, 2 species. New Guinea, Cochin China. Fossil. Eocene, Paris (1). Miocene, Dax (1). The three following genera are provisionally referred to Cer- thiade. CERITELLA, Morris and Lycett, 1850. Etymology, diminutive of Cerithiwm. Synonym, Tubifer (pars), Piette, 1856. Type, Ceritella acuta, Mor. and Lyc. Shell turreted, subulate, spire acute; whorls flat, margins usually sulcated; last whorl large; aperture elongated and narrow; canal short; columella smooth, rounded, and slightly reflected at the base; outer lip thin. Fossil, 17 species. Middle Jurassic strata. England, France. BRACHYTREMA, Morris and Lycett, 1850. Etymology, brachyos, short, and tremos, a cut. Examples, B. Buyignieri, Mor. and Lyc., R. Wrightii, Cotteau (Fig. 13). Shell small, turreted, turbinated; whorls either costated, nodulated, or cancellated; the last whorl large and yentricose; columella smooth, rounded, twisted near its base, and reflecting outwards, { forming a short, oblique canal; aperture moderately subovate, its length being usually less than that of the spire. Some species, as B. varicosa and B. pygmea, Fig. 13. acquired at certain arrests of growth thickened PBrachytrema _ duter lips or varices, as in Triton. a 23 MANUAL OF THE MOLLUSCA. Fossil, 16 species. The greater number belong to the Great Oodlite, others occur in the Kelloway Rock. England, France. MeEsostomA, Deshayes, 1864. Example, M. grata, Dh. Shell elongated, turreted, scalariform; aperture nearly cir- cular, dilated, obliquely cut, terminating in front by a semi- canaliculated angle; columella slightly concave, cylindrical, obliquely truncated, hp simple, and shghtly expanded. Fossil, 4 species. Eocene. Paris basin. [Famiry APORRHAIDA, Gray, 1856, | Includes the genera APORRHAIS (see p. 244), PTERODONTA, STRUTHIOLARIA (p. 246), and HALIA; also ALARIA, Morris and Lycett, 1854. Synonym, Tessarolax, Gabb, 1864. Etymology, ala, a wing. Examples, Alaria trifida, Phillips, sp.; A. cingulata, Pictet - and Roux, sp. Shell turreted, fusiform, terminating anteriorly by a canal; wing digitated or palmated, formed by the prolongation of the free border of the last whorl, and which is appled against the last whorl but one, but never adheres to the rest of the spire; posterior canal wanting; right lip without a sinus. Distribution, about 50 species. Jurassic. Hurope, Himalaya Mountains, South Africa. Cretaceous, 9 species. England, France, Germany. The species of this genus have been referred to Rostellaria, Pierocera, and Aporrhais. DIARTHEMA, Piette. Shell with continuous varices. Distribution. Lower Oolites. France. Pelicaria vernis, Adams, has a spiral she}l; the spire of adult covered with an enamel coat; aperture ovate; outer lip sinuous, — ? BULIMELLA, Hall, 1857. , Shell more or less fusiform; whorls convex, the last one mu enlarged; columella truncated ; outer lip thin, with a slight notch or sinus at the margin near its junction with the pillar. Distribution, 3 species. Carboniferous. Indiana. 24 sharp-edged. * J GASTEROPODA. ~ [FAMILY VERMETID. } The shells of species of this family are distinguished from those of the Serpulce by the presence of a spiral nucleus and of concave smooth interior septa. If the shell is formed of a solid matter strongly sculptured with longitudinal grooves or scales, or of a brownish colour, it is certainly formed by a Vermetus; but if the shell is of a soft earthy matter, feebly longitudinally grooved, it is doubtful to which it belongs. The shells of the Serpulide haye an anal opening (except Cymvspira), and appear only to be composed of two layers, the Vermetide having three. The interior of several species contains very long lamelle, generally regarded of generic value; but they are dissolved with age, like the teeth of some species of Pupa. All the Vermeti are viviparous, and the lamelle within the titbes may serve for the retention of the fry. The genera and sub-genera contained in this family are VER- METUS (Petaloconchus, Serpulorbis) (p. 249), and SILIQUARIA (p. 249). [FAMILY CzcrpZ. | Sheli with a spiral nucleus; tubular, regular, sometimes fixed aperture orbicular ; operculum horny, multispiral; margin sometimes fimbriated. CzcumM, Fleming.* Nuclear whorls orbicular, in the same plane as the adult, fre- quently decollated; operculum concave or flattened. Sections :—Elephantulum. Comparatively of large size, tapering; sculpture longitudinal. Distribution, 9 species. Mazatlan (6), West Indies, Mauritius. Fossil, 1 species (C. liratum), Carpenter. Cor. Crag. Sntton. Anellum (typical Czeca). Adult shell annulated. Distribution, 14 species. Europe, Matzatlan, Australia, Japan. Fossil, 2 species. Eocene. Paris, Suffolk. Fartulum. Smooth, cylindrical. Distribution, 10 species. Mazatlan, Teneriffe, Singapore, Australia. Fossil, C. mamillatum, 8. Wood. Cor. Crag. Sutton. Sub-genera :—BROcHINA, Gray. Type, Dentalium glabrum, Mont. ® See p. 249 fe) 26 MANUAL OF THE MOLLUSCA. Shell like Ceecum, smooth; aperture simple, acute; apex closod by a mamillated plug; operculum, convex. Distribution, 2 species. Europe, West Indies, Mazatlan. MEIOCERAS, Carpenter. Etymology, meion, rather small; ceras, horn. Young shell spiral or flat; adult somewhat inflated; aperture oblique; operculum spiral, scarcely concave. Distribution, 3 species. West Indies. STREBLOCERAS, Carpenter, 1858. Etymology, streblos, twisted; ceras, horn. Shell with the spire not decollated, no plug formed ; nuclear whorls orbicular, perpendicular to the plane of the adult; the plane of growth is flat, asin Cecwm, but some examples have a slight twist, forming an approach to Meioceras. Fossil, 4 species. Eocene. Hampshire, Paris. FAMILY V.—TURRITELLIDE* Includes TURRITELLA, PROTO, MESALIA, and CASSIOPE, Coquand, 1865. Synonym, Omphalia, Zekeli, 1852 (non Omphalius, Philippi, 1847). Example, Turritella Renauxiana, D’Orbigny. Shell thicker, and with more rapidly increasing whorls than in Turritella, often pupiform; aperture rounded, continuous; outer lip notched or sinuated by an impressed furrow, which winds round the last whorl; columella usually distinctly um- bilicated. Distribution, 32 species. Cretaceous. Europe, India, and America. [FAMILY SCALARIADZET | Includes ScaLARIA and the sub-genera Lglisia, Pyrgiscus, and Cirostrema, Morch. Shell solid, varices irregular, whorls generally cancellated. CocHLEARIA, Braun. Synonym, Chilocyclus, Bronn. * See p. 248, 17 See p. 250, rid 4 cs GASTEROPODA. Shell tarriculated, thick ; aperture circular, continuous, with a large expanded border. Fossil, 2 species. Saint Cassian beds, Austria. HOLOPELLA, McCoy, 1852 Example, H. gregaria, Sow. (Turritella), Sil Syst. t. 3, f. 1. Etymology, ’olos, entire, and epe, an aperture. Shell elongated, slender, of numerous gradually increasing whorls, generally crossed by slightly arched strize; mouth cir- cular, with the peristome entire; base rounded, with or without a minute umbilicus. The shells of the species oe this genus differ from those of Turritella in the continuous peristome and definite round margin to ms aperture, thus approaching much nearer to Scalaria. Fossil, 12 species. Silurian—Trias. Europe, United States. FAMILY IV.—MELANIADa.* MELANIA.—Tentacles long, with eyes on the exterior side at about a third of the length; margin of the mantle festooned. Sub-genera, Vibex, Melanatria, Hemsinus, and Philopotamis, Layard, P. sulcata, Reeve, sp. Operculum sub- spiral; nucleus marginal, Shell solid, paludiniform. Distribu- tion, species. Ceylon. Habit of Tanalia. Patupomus (Type, P. conicus, Gray), as restricted by the separation of Philopotamis and Tanalia, is characterised by the concentric structure of the adult operculum resembling that of Paludina, and a spiral nucleus situated about the middle of its height, and nearest to the left margin. Distribution, India, Burmah, Egypt, East Indian Archipelago, Mauritius, Ceylon (2 species, reduced from 14). In tanks and marshes. Sub-genus, Tanalia, Gray. Synonym, Ganga, Layard, founded upon certain monstrous forms of 7’. aculeata. Type, T. aculeata Chemnitz. Shell semiglobose, costate, nodulose; mouth very large, ovate; operculum unguiculate; nucleus marginal. Distribution, 2 species. Inhabiting mountain streams, ad- hering to rocks, or crawling over sandy bottoms, Ceylon. Fossil, 2 species. Upper Chalk. Gosau * See p. 246, &c. 2 27 MANUAL OF THE MOLLUSCA. Io, Lea, 1831. Synonyms, Melafusus and Ceriphasia, Swainson; Pleurocera and Strepoma, Raf.; Trypanostoma, Lea; Telescopella, Gray. Type, I. fluvials, Say (Fusus). Animal with the mantle margin plain; eyes at the base of the tentacles, which are short; operculum subspiral. Shell fusiform, inflated, conical or oval; aperture produced into a more or less obyious canal in front. Distribution, 100 species. North America, Sub-genera, Lithasia, Haldeman, 1840. Synonyms, Angi trema, Haldeman; Potodoma, Sw.; Glotella, Gray. Columella callously thickened above and below; base of aperture notched. Distribution, 31 species. North America. Strephobasis, Lea, 1861 (Megara sp., A. and H. Adams} Shell with a retorse canal at the base of the squarish aperture. Distribution, 8 species. North America. GyYRoToMA, Shuttleworth, 1845. Synonyms, Goniobasis, Lea, 1862; Euryccelon, Lea. Shell solid, oval, oblong, or turreted ; many forms resemble Paludomus; aperture subrhomboidal, subangular in front, without a canal; columella frequently callously thickened above ; operculum subspiral, as in Melania. Distribution, 289 species. United States. Fossil, 8 species. Eocene. North America. Sub-genera, Schizostoma, Lea, 1842 (Schizochilus, Lea; Mela- toma carinifera, Anthony); aperture with a slit in the upper part of the outer lip immediately under the suture. Distribu- tion, 27 species. North America. Meseschiza, Lea, 1864. Slit in the middle of the outer lip, M. Grosvenori. Indiana. PALADILHEA, Bourguignat, 1865. Dedicated to Dr. Paladilhe. Shell somewhat resembling that of Acme; test thin, crystal- line, extremely fragile; base of aperture produced in front; peristome continuous, thin, truncated; outer lip with a slit towards the suture. Distribution, 3 species. Fresh-water deposits. Herault, Om of the species is living in the neighbourhood of Montpellier. ~ 28 - GASTEROPODA. BUGESIA, Paladilhe, 1866. Shell resembling somewhat a very small Cerithiwm or micro- scopic Lithasia, but differing generically in having a wide, compressed, not callous columella like that of Lacuna. Distribution, B. Bourguignati. In washings of the River Lez, Montpellier. ANCULOSA, Say, 1821. Synonyms, Leptoxis, Rafinesque; Anculotus auctores. Type, A. preemorsus. Shell oval; aperture entire and rounded in front; columella eallously thickened above. Distribution, 31 species. North America. MELANOPSIS, including Pirena, see p. 248, W. M., ii. Faminy VII.—PALUDINID=.* The genera contained in this family are— PALUDINA, AMPULLARIA (Pomus, Marisa, Asolene), LANISTES, MELADOMUS, BITHINIA, with the following sub-genera of the last :— Stenothyra (Nematura), Hydrobia, Syncera, Paludinella, Lit- torinella, Amnicola, and MoItEssIERIA, Bourguignat, 1863. Type, Paludina Simoniana, Charpentier. Shell somewhat similar to that of Acme; test pitted; de- pressions octagonal, tetragonal, and rounded according to their position; peristome externally thickened; no operculum has been observed. Distribution, 1 species. Saline springs at Fouradade (Py- renees). Fossil, 3 species. Alluyium of the river Garonne, at Toulouse. PomaAtiopsis, Tyron, 1865, Synonym, Chilocylus, Gill. Shell elongated ; margin of aperture slightly expanded ; oper- culum corneous, subspiral, without an internal process. Animal like that of Hydrobia, but the foot is furnished with lateral sinuses ; terrestrial or amphibious. Distribution, species. America. ® See p. 257, &e, 29 MANUAL OF THE MOLLUSCA. [FAMILY Rissoiz] Includes LitioPa (p. 255), Rissora (p. 256), Rissoa (p. 258), and the following additional genera :— DiasToMA, Deshayes, 1864. Type, Melania costellata, Lamarck. Shell elongated, turreted; whorls with varices; aperture very oblique, semi-lunate, entire; base sinuated, subangular; pos- terior angle acute, detached from the penultimate whorl; lip thin, curved; columella concave, depressed, narrow. Fossil, 4 species. Eocene. Paris basin. AMPHITHALAMUS, P. Carpenter, 1865. Type, A. inclusus. West Coast of North America. Sheli like Rissoa, nucleus large; aperture with a produced lip, suddenly contracted in the adult. This genus bears the same relation to Rissoa that Stoastoma does to Helicina. KertLostoma, Deshayes, 1848. Type, Melania marginata, Lamk. Shell elongated, turricuiated, regularly conical; generally striated transversely. Aperture entire, short, effuse at the base, angulated posteriorly; columella short, callous; the peri- stome entire, the left lip broad and thick, the right broadly ‘ margined. Fossil, Kocene, 6 species; Paris basin. Belgium, England, Punjaub. Cretaceous, 5 species; India, Gosau. PTEROSTOMA, Deshayes, 1864. Type, P.tuba. Eocene. Grignon, Paris. Shell elongated, turriculated ; peristome continuous, circular, very dilated and margined; columella very broad, expanded, and continuous with the peristome. ScALIoLA, Adams, 1860. Type, 8. bella. Animal with the rostrum elongated, cylindrical, annulated, bifid at the end; tentacles filiform, eyes rrominent, black at — the outer base of the tentacles; foot short, ovate, posteriorly sub-acuminate; operculum corneous, oyate, subspiral; nucleus subterminal, 30 a’, © GASTEROPODA. Shell turreted, umbilicated or rimose; aperture more or less circular ; peristome continuous; margin straight, acute. The species have the habit of agglutinating grains of sand to the surface of the shell. Distribution, 4 species. Japan, Philippines, 2—70 fathoms. Fossil, 1 species. Oligocene, Latdorf. MicrosTELMA, A. Adams, 1863. Type, M. Deedala, Adams. Japan, 48 fathoms. Shell turreted, ovate, rimose, somewhat resembling Pyrami- della ; spire conical; whorls longitudinally plicated. Aperture oblong, produced in front, sub-canaliculate; columella thick- ened, straightish ; lip simple. Fossil, 1 species. Sub-apennine formation. Asti, Italy. BARLEEIA, Clark, Named in honour of the late G. Barlee. Type, Turbo ruber, Montagu. Britain, Mediterranean. Animal and shell related to Rissoa ; mantle and opercular lobe destitute of filaments; operculum solid, auriform, and gibbous, nucleus excentric. Distribution, 3 species. Atlantic and Pacific Oceans. [FamIty SKENEIDE ] Includes Skenea (p. 256), and HomAoeyra, Jeffreys, 1867. Synonyms, Omalogyra, Jeffreys; Spira, Brown; Ammoni- cerina, Costa, 1861. Etymology, a flat circle. Type, H. atomus, Philippi (Skenea nitidissima, F’. and H.). Animal with a flattened body, no tentacles; eyes sessile, and placed behind the head. Shell minute, forming a flat coil; spire invyolute; whorls more or less angulated ; mouth clasping both sides of the peri- phery ; operculum few-whorled, with a central nucleus. The upper part of the body of H. atomus is partially ciliated. The tongue has only a single row of teeth, resembling miniature shark’s teeth. Distribution, 2 species. In pools, and just beyond low water, on sea-weeds and Zostera. Norway, Britain, France, shores of the Mediterranean. Fossil, upper tertiary deposits. 31 MANUAL OF THE MOLLUSOA. FAMILY VI.—LITTORINIDZ.* The genera are— Litrormna, including Tectaria, Modulus, and Risella; LACUNA, and Fossarvs, Philippi (p. 253). Synonyms, Phasianema, Wood; Maravignia, Arados. Shell perforated, sculptured ; inner lip thin; aperture semi- lunate; operculum not spiral. Animal with two frontal lobes between the tentacles. Distribution, 43 species, including species of the sub-genera. Mediterranean and tropical seas. Fossil, 4 species. Miocene. Europe. Sub-genera, Conradia, Couthouyia, Cithna, Cottoina. Fossarina, Adams, differs from Fossarus in the curyed inner lip and circular aperture. 2 species. Australia. Isapis, H. and A. Adams. Columella with a plait; in J. anomala it is almost obsolete. 4 species. Jamaica and Mazat- lan. LACUNELLA, Deshayes, 1864. Etymology, diminutive of Lacuna (see p. 255). Type, Li. depressa, Desh. Eocene. Paris. Shell ovate, thin, pellucid, shining, very depressed; apex. obtuse; aperture large, dilated; outer lip thin, reflected; colu- mella narrow, thin, concave, grooved, with the base perforated. ? RAULINIA, Mayer, 1864. Dedicated to M. Raulin. Type, Odostomia alligata, Deshayes. Eocene. Paris basin. Shell turbinated, oval-oblong, moderately thick, spirally sul- cated; whorls rapidly increasing, convex; last whorl very large; aperture large, angulated posteriorly, expanded in front ; columella broad, arcuate, flattened, with a prominent tuber- culous tooth. Evoycuvs, E, Deslongchamps, 1860. Etymology, eu-kuklos, circling, in allusion to the numerous plications or rings of the spire and base. Examples, Turbo ornatus, Sow. ; T. capitaneus, Miinst. * See p. 250, 32 —S | GASTEROPODA. Synonym, Amberleya,* Morris and Lycett. Shell very thin (without a nacreous layer?) ; spire elongated, almost turriculated ; surface ornamented by longitudinal plica- Fig. 14. Eucyclus goniatus, Desl.. tions and nodes; aperture oval, angular above; lip semi- circular, thin; columella flattened, imperforated. Fossil, 23 species. Upper Lias— Kelloway Rock. England France, Germany. [FAMILY SoLARID2] Contains— SOLARIUM (see p. 253). Sub-genera, Torinia, Gray. Philippia, Gray (p. 253). Shell trochiform ; uinbilicus small, Fossil, 3 species. Miocene. America. Disculus, Deshayes. Shell discoid; umbilicus very narrow, inferior angle of the aperture extended and oblique. ADEORBIS (p. 266), Crrrus (p. 271), DIscoHELIx (p. 253), EUOMPHALUS (pp. 267, 346), BIFRONTIA (p. 253), PLATYSTOMA (p. 254), PHANEROTINUS (p. 267), MACLUREA (p. 348). * This name was pubiished in 1854, but the genus was insufficiently characterise4, ce 33 MANUAL OF THE MOLLUSOA. OPHILETA, Vanuxem (p. 267), was founded on species of Maclurea, with very slender whorls. Mr. Billings regards them as distinct, and distinguishes them as follows :—‘‘ In Maclurea the aperture is entire, and the whorls usually large, but in Ophileta it has a sinus below and a notch above, while the whorls are usually more slender. ‘In Maclurea crenulata (Billings) there is a sort of spiral band, and also there are indications of a sinus in the lip on the flat side, but they are only incipiently developed.” —( Billings.) STROPHOSTYLUS, Hall. Etymology, strepho, I turn, and stylus, columella. Shell subglobose or ovoid ; spire small, body whorl large and — ventricose; outer lip thin; columella twisted or spirally grooved within, not reflected; umbilicus wanting; aperture ovate or transversely oval; apparently related to Platystoma. Distribution, 10 species. Silurian. United States. HeEtiocryptus, D’Orbigny, 1850. Shell depressed, orbicular; whorls embracing; umbilicated on both sides; aperture vertical, oval transverse. Distribution. H. pusillus, Coral Rag, France, Germany ; H. radiatus, U.G.S. Blackdown, Mans. [Faminy [ANTHINIDE] Includes— IANTHINA and RECLUZIA (see p. 285). Famity XII.—CALYPTRAIDZ.* PLATYCERAS, Conrad, 1840 (see p. 277). Type, Pileopsis vetusta, Sowerby. Synonyms, Acroculia, Phillips, 1841; Orthonychia, Hall, 1843. Shell depressed, subglobose to oblique, subconical; spire small; whorls few, free or contiguous; aperture more or less expanded, often campanulated, entire or sinuous. Many species show a sinuosity of the strive, indicating a notvh in the margin of the aperture during the first stages of growth. Mr. Hall has been unable to recognise the peculiar muscular impressions which are characteristic of Pileopsis. Specimens of some species show the expansion of the columellar lip, and its partial or entire union with the yolution, presenting all the * See p. 275. 34 - a) Pot GASTEROPODA. appearance of a thin columella with a deep umbilicus. P. dwmosum is spiniferous ; P. subrectum is simply beitt or arcuate. Distribution, 46 species. Silurian—Carboniferous. Europe, North America. Faminy IX.—TuRBINIDE* Includes PHASIANELLA (p. 263), IMPERATOR (p. 264), TURBO (p. 263), with the following sub-genera :— Callopoma, Gray. Distinguished by the extreme complexity of the operculum. ‘The opercula of C. fluctuosuwm, Gray (Turbo) (Maz.), are flat, and covered with a dark horny layer inside, dis- playing about 6 whorls. Outside with a broad, central, spiral callus, white and granular, concealing the umbilicus, with extremely minute pustules over the surface, sometimes with a few sharp prickles. A deeply cut groove surrounds the callus, followed by a green, plaited, spiral frill prickly inside. Between this and the outer margin are 4—6 fine emerald necklaces, sup- ported on slender spiral ribs, with deeply channeled interspaces. The operculum of C. saxoswm, inhabiting Panama, is formed on @ much coarser plan.’ —(P. Carpenter.) Uvanilla, Gray. Example, U. olivacea, Mexico. Distinguished by the absence of an umbilicus, and the bi ridged operculum. Distribution, 3 species. Mazatlan, Mexico. PHASIANELLA. Sub-genus, Lucosmia, P. Carpenter, 1864. Hiymology, eu, well, and cosmia, adorned. Shell solid, variegated as in Phasianella ; aperture and whorls round; axis wmbilicated. Distribution, 4 species. Cape St. Lucas. TROCHUS. With the following sub-genera and sections :— Margarita, Leach (p. 265). Example, T. helicinus, Fabr. Shell small, pearly, and umbilicated; lateral cirri, 8—7 in British species. No typical Trochi appear to inhabit North-East America, only those of this section. 38 species, Britain. Gibbula, Leach (p. 265). Example, T. magus, Linné. Shell low-spired and umbilicated ; lateral cirri, 3 on each side in the British species. Circulus, Jeffreys. Shell very small, nearly flat-spired, with an exceedingly wide and open umbilicus. Hxample, Delphinula * See p. 263. 35 MANUAL OF THE MOLLUSOA. ’ Duminyi,* Requien; lateral cirri, 3 on each side (sometimes 4 on one side, and 3 on the other.—Clarke). Fossil, in the Coral- line Crag; Britain; Catania. Living, Britain; Mediterranean. Trochocochlea, Klein. Spire moderately raised ; base, slightly umbilicated in the adult, perforated in the young, pillar lip with a strong tubercular tooth. Lateral appendages 3 to 4 on each side. Example, T. lineatus, Da Costa. Britain, France, Spain, Mogador. Ziziphinus, Leach. Spire pyramidal, base imperforated ; pillar lip notched or angulated at the lower part. Lxample, T. granulatus, Born. 7 species, Britain. Omphalius, Philippi. YZype, Trochus viridulus, Gmel. Mazatlan. Shell with a spiral ridge surrounding the umbilicus, ending in one or more tubercles on the columella. Distribution, 4 species. Mazatlan, China. Pyranis, Enida, ke. ROTELLA (see p. 265). Sub-genera. Jsanda (I. coronata), Adams. Shell orbicular, conical, pillar edge crenated; whorls rounded; axis umbili- cated ; operculum orbicular, of many whorls. Chrysostoma, Gray. Turbo Nicobaricum, Gmel., related to Isanda. Pillar edge callous; operculum horny, spiral. Microthyca, Adams, differs from Jsanda in its continuous peri- stome and thickened outer lip. 1 species, Japan. Umbonella, Adams. Shell porcellanous, small, turbinated, allied to Chrysostoma, but the aperture is circular, and the axis imperforate. 1 species, Japan. LEUCORHYNCHIA, Crosse, 1867. Etymology, leucon, white; rhynchion, a beak: Type, L. Caledonica, Crosse; inhabits under stones, New Caledonia. Shell depressed, sub-discoid, umbilicated, polished, of few whorls; aperture rounded, not nacreous. A thick callosity arises from the front margin of the aperture and the columella lip, and is continued as a free rostrated process over the um- bilicus. Operculum corneous, rounded, multispiral; nucleus, central. * Adecrbis supranitida and A tricarinata are varieties. 36 GASTEROPODA. TEINOosTOMA, H. and A. Adams, 1853. Type, T. politum. Synonym, Calceolina, A. Adams. Shell like Rotella, with a greatly produced mouth and callus. It resembles Cyclops among the Nasside, and in the appear- ance of the base Streptaxis and Anostoma among the Helicide. Distribution, 9 species. Japan, Mazatlan, St. Helena, Jamaica. Fossil, 10 species. Hocene. Paris basin. ETHALIA, H. and A. Adams. Shell of the general aspect of Vitrinella, but agreeing with Rotella in haying a callous base, and differing from the typical species of that genus in being frequently sculptured; in the callus winding round, generally not covering, the umbilicus; and in the outside of the callus not being glossy. The lip is generally not reflected over the body whorl. They appear to retain permanently the young state of Tei- nostoma. Distribution, 12 species, inhabiting deep water. Mazatlan, Jamaica, Japan. MOoONODONTA. DELPHINULA (including Collonia, Liotta, Serpularia, and Crossostoma). CYcLOsTREMA, with Adeorbis and Vitrinella as sub-genera. STOMATELLA, GENA, and BRODERIPIA. FAMILY X.—HALIOTIDA, Sub-family, HALIOTINZA. Genera—HALIorIs (p. 268), SroMATIA (p. 268), TEINOTIs (p. 269). Sub-family, SclssURELLINE. Genera—ScIssURELLA (p. 269), PLEUROTOMARIA (p. 270), (Raphistoma and Scalites are merely sections of this genus), MURCHISONIA (p. 270), CATANTOSTOMA (p. 270), TRocHOTOMA (p. 271), with the following additional genera and sub-genera :— PLEUROTOMARIA (see p. 270). Sub-genera :—Leptomaria, HK. Deslongchamps, 1865. JL, amena, Deslong., sp. Shell ike Pleurotomaria ; the respiratory slit is narrow and elongated. - Distribution, Inferior oolite—Cretaceous. Cryptenia, E. Deslong., 1865. (Helicina, Sowerby) C. helici- formis, Deslong., sp. Shell of a rounded and compact form, 87 q surface smooth or but slightly ornamented, slit excessively short, sometimes reduced to a simple fold; the band occupies — the middle of the whorl, and is only visible on the body whorl. Distribution. The species are numerous in the Carboniferous system, and range to the Middle Lias. In the typical Plewrotomaria the sht is large, and the band is neyer concealed by the whorls of the spire. MANUAL OF THE MOLLUSCA. ScHIsMOPE, Jeffreys, 1856. Etymology, schisme, a slit, and ope, a hole. Synonym, Woodwardia, Fischer, 1861. Type, S. striatula, Ph. Mediterranean. Shell like Scisswrella, but the spire is laterally compressed, as in Stomatia, and is not so trochiform. Theslitin the peristome of the young shell is converted into a foramen in the adult; it does not commence until the animal is half grown. S. striatula is a littoral species, whilst all the species of Scis- surella inhabit deep water. Fossil, 1 species, Miocene, Bordeaux. Distribution, 4 species. Mediterranean,. Japan. Scissurella and Schismope are the analogues respectively to Pleurotomaria and Trochotoma, differing only in size; but in the two former genera the shell is translucent, not nacreous, as in the two latter. - . fi P " % * k em Di1TREMARIA* (pars, D’Orb.), E. Deslongchamps, 1865. Fig. 15. Ditremaria quinquecincta. a, Central tooth. 5, Callosity of the base. c, Tooth on the right. d, Tooth on the left Type, D. quinquecincta, Ziet. sp. Coral Rag. Natheim, &c. Shell trochiform ; in place of the respiratory slit of Trocho- toma, there are two elongated oval holes united by a transverse — fissure; the base of the shell presents a large callosity, the — umbilicus is deeply excavated, and a rounded tubercle arises p * See p. 271. 35 }- Z GASTEROPODA. from it; the aperture is contracted, and the upper angle of each lip bears a more or less distinct tooth. Distribution, 2 species, Great Oolite and Coral Rag, France and Germany. Sub-family—BELLEROPHONTINA. Genera :—PORCELLIA (p. 344), BELLEROPHON (p. 344) (with Bucania), and TREMANOTUS, Hall, 1863. Type, Bucania Chicagoensis, M‘Chesney. Shell thick, aperture dilated; having the form of Bucania, but with a row of isolated oval siphonal openings along the middle of the dorsal side. Fossil, 2 species. Upper Silurian, North America. ? CARINAROPSIS, Hall. Shell haying a patelloid aspect. Spire usually attenuated ; body whorl expanded abruptly; cavity shallow, presenting a kind of septum as in Crepidula. Fossil, 2 species. Silurian, America. FAmMILty XJ.—FISSURELLIDA. DESLONGCHAMPSIA, M‘Coy, 1850. Dedicated to Dr. Eudes Deslongchamps, the renowned French paleontologist. Type, D. EKugenei, M‘Coy, Mor. and Lye. Shell patelliform, apex acute excentric ; with a wide longitu- dinal anterior sulcus, produced into a rounded lobe. «This genus differs from Metoptoma in its ornamented surface, and the front margin being produced downwards into a rounded lobe. This latter structure would prevent the firm adhesion of the shell.” —(M‘Coy.) - Fossil, 3 species. Lower Oolites. England, Normandy, Galicia. FAMILY XIIT.—PATELLIDE. HELCION (Montfort, p. 278), Jeffreys. Etymology, a breast-collar. Synonyms, Nacella, Schumacher; Patina, Leach; Calyptra (pars), Klein. Haxample, H. pellucidum. (Patella pellucida, Linné), Shell semioyal, not resembling a peaked hat as in Patella ; 39 MANUAL OF THE MOLLUSCA. apex of embryonic shell slightly twisted; crown never pro- eal’ minent, incurved, and nearly terminal, usually thin, with an — opalescent hue. Animal. Mantle fringed at its edges with cirri; gills not so numerous as in Patella, and forming a shorter plume, which is interrupted over the head. Helcion lives on Laminaric and sea-weeds of a similar kind, and is therefore sublittoral. Distribution. Species few, but haying an extensive range. Europe, West and South Africa, Cape Horn, and Australia. Fossil, included in Patella. LEPETA, Gray (p. 281). Derivation, possibly from lepas, the ancient name of the limpet. Type, Patella czeca, Miller. Shell minute, apex posterior. Animal blind. PROPILIDIUM, Forbes and Hanley (p. 281). Derivation, from its affinity to the genus Pilidiwm. Type, P. ancyloide, Forbes. Shell similar to Lepeta, but differing in always haying a dis- tinctly spiral apex and a plate or septum inside the crown. Animal blind, as Tectura fulva and Lepeta ceca of this family. ‘) GASTEROPODA. Sub-geuus :—Taheitia, H. and A. Adams, 1863. Type, Truncatella porrecta, Gould, Taheiti. Operculum ~ shelly, furnished with erect radiating lamellee. Aperture of shell ovate ; last whorl separate; peristome continuous, expanded. ORDER III.—OPISTHO-BRANCHIATA. Faminty I.—ToRNATELLIDA. ETALLONIA, Deshayes, 1864. Dedicated to M. Etallon, a French paleontologist. Type, Ki. cytharella, Desh. Sheil ovate, subfusiform, resembling certain small Mitres ; spire short, conical, obtuse, few-whorled ; aperture elongated, narrow, base entire, subemarginate ; lip simple, acute, arched; columella thick, cylindrical, twisted in the middle to resemble an obtuse plait; acute anteriorly. Distribution, 3 species. Eocene. Paris basin, Valognes. ACTHONELLA.—Sub-genus, Volvulina, Stoliczka, 1865; (Actzeonella part, Meek, 1863). Type, Volvaria levis, Sowerby. Shell ovate, volvuliform, involute, more or less attenuate above, widest below the middle, entirely without any traces of a spire. Fossil, 5 species. Cretaceous. Germany, Syria. FAMILY VI.—DoRrIDz&. ANGASIELLA, Crosse, 1864. Dedicated to Mr. G. F. Angas. Type, A. Edwardsi, Port Jackson. Animal elongated, rounded in front, attenuated and pointed behind; mantle covering the head and foot; dorsal tentacles two, clavate as in Doris; gills plumose, less numerous, and placed in front of the anus as in Triopa, and occupying the median part of the back, a more forward position than in others of the Doride. PLOCAMOPHORUS, Ruppell. Example, P. Ceylonicus, Kelaart sp. Synonym, Peplidia, Lowe; ? Gymnodoris, Stimpson. Animal, similar to Polycera, but the tentacles are retractile within sheaths. Distribution, 3 species. Madeira, Australia, Ceylon. D2 83 MANUAL OF THE MOLLUSCA. Kauinea, Alder and Hancock, 1865. Etymology, an old Indian name for Jelinguna. Type, K. ornata, Ald. and Han. Coromandel coast. Animal with an obtusely rounded body; branchize plumose, non-retractile, surrounding the vent, but placed separately at a little distance from it on the posterior part of the back. [Famity Dormopsip#, Alder and Hancock, 1863.] Dorsal tentacles retractile within sheaths; no oral tentacles, Tongue atrophied, buccal bulb modified into a delicate suctorial retractile proboscis; mantle devoid of spicula. Dorimopsis, Alder and Hancock, 1863. Body depressed, oval or elliptical; mantle covering the head and foot, smooth, or with soft warty tubercles; dorsal tentacles laminated ; head minute, generally produced into small lateral lobes, without oral tentacles; branchize plumose, wholly or partially surrounding the vent on the media-dorsal line, retrac- tile within a common cavity. Distribution, 10 species. East Indies, China, Madeira. Famity VII.—TRITONIADZ.* Hero, Loven. Example, H. formosa, Loy. Animal with no mantle; tentacles two, linear, simple non- retractile; veil plain, produced at the sides, gills branched or umbellated. Tongue with a large central denticulated spine, and two simple lateral spines. Jaws corneous. [Famity EoLipip2. | PHIDIANA, Gray. Example, P. Patagonica, D’Orbigny. Animal with a stout body; dorsal tentacles clavate, laminated; oval tentacles very large; gills in close transverse rows; sides of the foot rounded. [Faminy EoLipz. } MADRELLA, Alder and Hancock, 1863. Type, M. ferruginosa, Ald. and Han. India, Animal ovate, depressed, with a distinet cloak. Dorsal ten- tacles with the upper portion papillated: no oral tentacles. Head broad, with a semilunar veil. Branchiz papillose or linear, placed in several rows round the margin of the cloak. Anus * See p. 332. 52 ie nd) tn taal mai ai BRACHIOPODA. lateral. Tongue narrow, with three pectinated plates in each row. Jaws large and strong, margins without denticulations. This genus is closely related to Antiopa. PHYLLOBRANCHUS, Alder and Hancock, 1863. Type, Proctonotus orientalis, Kelaart. India. Animal elongated, flattened on the back, angulated at the sides, without a distinct cloak.. Tentacles two, dorsal, longitudi- nally folded, bifurcate above, non-retractile. Head produced at the sides into angulated and folded expansions. Branchis leaf-like, with distinct foot-stalks, arranged in several rows along the sides of the back and round the head in front. Anus lateral. The tongue resembles that of Hermea. CLASS IV.—BRACHIOPODA.* FAMILY I.—TEREBRATULIDE.+ TEREBRATULA (see p. 363). Sub-genus, Rensseleria, Hall, 1859. Dedicated to the late Hon. Stephen Van Rensselaer. Examples, R. ovoides, Hall, Fig. 18; Terebratula strigiceps, Romer. Sheli ovoid or suborbicular, without mesial fold or sinus; beak prominent, acute, -more or less incuryed; foramen terminal, some- times concealed. Ventral yalye with, two diverging cardinal teeth supported. by strong dental plates. Dorsal valve with the dental sockets between the shell and a strong process from which the slender crura proceed, first in a direct line, and then one division of each, diverging into the centre of the ventralvalve, terminate in acute points. On the other side the divisions extend nearly at right angles to the axis of the shell into the cavity of the dorsal valve; and thence bending abruptly forward and gredually converging, Fig. 18, : The interior of the dorsal valve terminate above the centre of the shell of R. ovoides, showing the thick- - . : : ° ened processes at the beak, ths in a thin flattened or longitudinally ean he loop, and the narrow _ concave plate. longitudinal plate. * See p. 354. { See p. 363, 53 MANUAL OF THE MOLLUSCA. Rensseleria, if not synonymous with, is closely related to, Meganteris. Fossil, 11 species. Silurian to Devonian. Europe, North America. _CENTRONELLA, Billings, 1859. Etymology, diminutive of kentron, a spur. Type, Rhynchonella glans-fagea, Hall. Shell haying the general form of Terebratula. Dorsal valve with a loop consisting of two riband-like lamelle, which were united at an acute angle at the point of greatest extension, whence they recurve in a thin vertical plate which is not attached at either margin, approaching in some respects to Waldheimia. Distribution, 4 species. Devonian. North America. LEeproca:ttA, Hall, 1859. (Ccelospira, Hall). Appears to differ from Centronella only in consisting of species which have the surface ribbed instead of smooth. Distribution, 9 species. Mid. Silurian—Devonian. Europe, North America. No true Terebratulee haye been found in beds older than the Devonian. FAMILY II.—SPIRIFERIDZ.* SYRINGOTHYRIS, Winchell, 1863. Fig. 19. Section through the beak of the ventral valve of S. typa (Winchell). 1, dental plates or lamelle ; ¢, tube incomplete ; 7, mesial ridge. Examples, 8. typa, Winchell, Fig. 19; Spirifera distans, Sow. Shell like that of Spirifera, with an elongated hinge-line. Ventral valve with a broad mesial sinus, a very broad area, and j a narrow triangular fissure closed towards the apex by an external conyex pseudo-deltidium ; beneath which, and diverg- ing from it, is another transverse plate connecting the vertical dental lamelle, which are incurved so as to nearly join their inferior edges, thus forming a fissured tube, which projects beyond the limits of the plate from which it originates into the interior of the shell. A low median ridge aon from the See p. 271. ot =" BRACHIOPODA. beak to the anterior part of the valve. Dorsal valve depressed without an area, and with a distinct mesial fold. Shell-structure punctate. Fossil, 2 species. Carboniferous. United States, Ireland, Belgium. Cyrtina, Davidson, 1858. Etymology, modified from the diminutive (Cyrtidiwn) of Cyrtia. Examples, C. heteroclyta, C. Demar- li, and C. septosa. Shellresembling Spirifera, but with- out the vertical shelly plates which diverge from the extremity of the beak. Interior of ventral valve with two con- tiguous vertical septa, which coalesce into one median plate, which extends from the extremity of the beak to within a short distance of the frontal margin, and then diverges to form dental plates, as in Pentamerus. The fissure is co- . oe peter sneer ee vered by an arch-shaped deltidium ; ¢eltidium ; 2, v-shaped chamber. but in C. Demarlii the median aos is continued as far as the under surface of the deltidium, and the dental plates are fixed to the sides, instead of the upper edge, as in C. heteroclyta and C. septosa. ‘Spiral coils haying the same position asin Spirifera, but the two first coils are connected a little in front of the mid- length by an apparatus somewhat like that of Spirigera, but not so complicated. A very slender process springs upwards towards the ventral valve from each coil, and, at a height of _ about one line, curves forwards. The two then unite and forni a single band, which extends forwards to about the front of the coil, and there ends in an obtuse point.”’—( Billings. ) Distribution, 9 species. Deyonian—Trias. Europe and North America. MERISTELLA, Hall, 1860. Etymology, diminutive of Merista, an allied genus. Examples, Atrypa tumida, Dal. ; Meristella levis, Hall. Shell oval, ovoid, orbicular or transverse, Valves unequally conyex, with or without a median fold and sinus; beak appa- rently imperforate, incuryed; area none. Surface smooth or 5d MANUAL OF THE MOLLUSCA. vonceutrically striated. Dorsal valve with a longitudinal septum; upper part of the ventral valve with a deep sub- triangular muscular impression which unites with the rostral ~ cavity. The species of this genus are Meriste without the peculiar © appendage of the ventral valve. Distribution, 17 species. Silurian—Devonian. Europe, North America. The forms marked by plications on the mesial fold and sinus, and sometimes with obscure or distinct plications on the lateral - portions of the shell, constitute the genus LEIORHYNCHUS, Hall. 4 species. Devonian. United States. CHARIONELLA, Billings, 1861. Synonym, Cryptonella, Hall, 1861. Type, Athyris scitula. Shell resembling Athyris, but more elongate-ovate or ap- proaching to Zerebratula inform. Internal spires as in Athyris and Merista, but the dorsal hinge-plate is either obsolete along the middle, or anchylosed to the bottom of the valve. Foramen— terminal, bounded on the lower side by one or two deltidial pieces, or by a portion of the shell. The mesial septum in the dorsal valve is either absent or rudimentary. Distribution, 15 species. Devonian. America, Spain. NUCLEOSPIRA, Hall, 1859. Etymology, nucleus, and spira. Types, Spirifer pisum, Sowerby; Nucleospira ventricusa, Hall, Figs. 21, 22, 23. : J ae se B-. 2 i) . S : -_ ‘f <— Fig. 22, Fig. 23, Nucleospira ventricosa. Fig. 21, interior of the dorsal valve. Fig. 22, interior of the ventral valve. Fig. 23, interior of the dorsal valve, with a portion of the ventral valve attached. : J, cardinal process ; ¢ c, crural processes ; 6 6, dental pockets ; 7, muscular impres- sions; s, medio-longitudinal septum; ¢t, teeth; 2-a flattened space or false area — beneath the beak. (/ull.) % ys = 56 BRACHIOPODA. Shell punctate; spheroidal; beaked; hinge line shorter than the width of the shell; cardinal extremities rounded. Internal spires as in Spirifera. Ventral valve with a flattened space or false area beneath the beak, on each side of which, at the base, is a strong tooth; a narrow medio-longitudinal septum extends from the beak to the base. Dorsal valve furnished with a strong spatulate cardinal process, which, rising vertically from the cardinal margin, is closely grasped at its base by the cardinal teeth of the other valve; and thence bending abruptly upwards, and expanding, is projected into the cavity of the opposite beak, lying close upon the under side of the false area. Cardinal pro- cess grooved to allow of the passage of the peduncle, for the protrusion of which a minute foramen is sometimes observed in the beak. The crural processes originate at the base of the cardinal process. A medio-longitudinal septum as in the ventral valve. Surface of shell apparently smooth, under a lens punctate; when perfect, covered with minute hair-lke spines. The larger species of this genus present some analogy in external appearance with Spirigera, and the presence of internal spires increases the similarity. The cardinal teeth resemble those of Spirigera and Merista. In form, and in the punctated test, it simulates Magas; while the elongate cardinal process of the dorsal valve resembles that structure in Thecidium. Distribution, 7 species. Silurian. United States, England TREMATOSPIRA, Hall, 1859. Hiymology, trema, a foramen, and spira. Example, T. multistriata, Hall. Shell transverse, elliptical, or subrhomboidal, furnished with internal spires (arranged as in Spirifera); hinge line shorter than the width of the shell. Valves articulated by teeth and sockets; beak of ventral valve produced or incuryed and trun- cated by a small round perforation separated from the hinge line by a deltidium. A deep triangular pit or foramen beneath the beak, which is filled by the closely incurved beak of the dorsal valve. False area sometimes defined. Distribution, 7 species. Upper Silurian—Middle Devonian. United States. This genus and the next appear to be closely related te hetzia. d3 57 MANUAL OF THE MOLLUSCA. RHYNCHOSPIRA, Hall, 1859. Etymology, pvyyoc, a beak, and spira ; in allusion to its z similarity in form to Rhynchonella, and haying internal spires. Type, Waldheimia formosa, Hall. Shell somewhat similar to Rhynchenella, but usually more symmetrically rounded, and with less distinct mesial sinuosities ; _ and in these characters they resemble Waldheimia. Valves articulated by teeth and sockets, similar to those of Nucleospira; the crura supporting two conical spires. The cardinal process of the dorsal valve is a broad emarginate plate ; beak of the yentral valye largely perforated. Surface plicated or striated. Distribution, 7 species. Silurian—Devonian. United States, Russia. ATRYPA (see p. 378). The internal appendages of Atrypa reticularis (see Fig. 24) consist of a pair of spiral cones, placed side by side, with their apices directed towards the cavity of the dorsal valve; the — lamellee have their origin on the socket-walls, and run parallel with the inner margin of the valve. ‘ ° . Electric Lighting. ELECTRIC LIGHT : Its Production and Use. Embodying Plain Directions for the Treatment of Voltaic Batteries, Electric Lamps, and Dynamo-Electric Machines. By J. W. Urgunart, C.E., Author of ‘‘ Electre- plating: A Practical Handbook.”’ Edited by F.C. Wess, M.1.C.E., M.S.T.E. Second Edition, revised, with large Additions and 128 Illusts. 7s. 6d. cloth. ** The book is by far the best that we have yet met with on the subject.”"-—4then@uni. “It is the only work at present available which gives, in language intelligible for the most part t> the ordinary reader, a general but concise history of the means which have been adopted up to the present time in producing the electriclight. . . . 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Athali Trade, Manufacture of Sulphuric Acid, etc, A MANUAL OF THE ALKALI TRADE, including the Manufacture of Sulphuric Acid, Sulphate of Soda, and Bleaching Powder. By ee Lomas, Alkali Manufacturer, Newcastle-upon-Tyne and London. With 232 Illustrations and Working Drawings, and containing 386 pages of Text. Super-royal 8vo, £2 12s. 6d. cloth. * * This work provides (1) a Complete Handbook for intending Alkali and © Sulphuric Acid Manufacturers, and for those already in the field who desire to improve their plant, or to become practically acquainted with the latest processes and developments of the trade: (2) a Handy Volume which Manufacturers can put into the hands of their Managers and Foremen as a useful guide in their daily rounds of duty. Synopsis of Contents: Chap. I. Choice of Site and General Plan of Works.—II. Sulphuric Acid.—III, Recovery of the Nitrogen Compounds, and Treatment of Small Pyrites.—IV. The Salt Cake Process.— V. 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