NRLF B EARTH A SYNOPTICAL TABLE OF THE CONTENTS DR. LARDNER'S CABINET CYCLOPEDIA (TO BE COMPLETED IN TWO MORE VOLUMES,) Fcp. 8vo. with Vignette Titles, 6s. each volume, bound in cloth. Pore Silk A.ut.1 Brit: Earl Chrc The Den Eng Eur. Frai Gen Gra Gret Irela Itali Mar Net! Out! Pola The Fall Ron Rus Scot Spai Swit Unil Prel Geoj Hab Anil Bird Boti Fish Geo! Inse Qua SheJ Tax EARTH SCIENCES Prel Arit Asti Chemistry - - - - - Electricity and Magnetism kc. oke nslo lips 1 vol. 2 vols. Geometry, and ite application 1 vol. Heat - - - 1vol. History 1vol. Hydrostatics and Pneumatics 1 vol. Mechanics l*ol. Optics - - 1 vol. Essay on Probabilities - - 1 vol. 34 - , 130, 131 Professor Uonova:! Dr. Lardner, and C. V. Walker. Dr. Lardner. Dr. Lardner. Professor Powell. Dr. Lardner. Kater and Lardne Sir D. Brewster. Professor De Morg Wilson and Ogilvy. 57. Skinner Street. SnowluU. London, ON N 3 SSL _ OR 'THE ItATimAL L'LASSI]-' ( OF SHELLS (^7)} SHELL * Ixmiixm-. CONTENTS. PART I. A GENERAL SURVEY OF THE TESTACEOUS MOLLUSCA. CHAP. I. Introductory Observations — The Mollusca in general — The Characters and Analogies of the three primary Divisions or Classes ; namely, the Acrita, the Radiata, and the Testacea — Notes on the Bibliography and the existing Classifications of the latter - Page 1 CHAP. II. On.the Testaceous Mollusca in general, the primary Divisions, and their Analogies to the Vertebrata and Annulosa - 26 CHAP. III. On the Order of Gasteropoda, its primary Divisions, and the Characters and Analogies of the Muricidas and the Turbinellidae - -53 CHAP. IV. The Zoophaga, or Predaceous Shell-fish, continued The Family of Volutids, or Volutes - - 97 CHAP. V. The Predaceous Gastropods continued — The Strombidse, or Wing- Shells - - 136 CHAP. VI. .On the Phytophagous Tribe of Shell-fish. — The primary Divisions or Families. —The Helicidae, or Land and Freshwater Snails - 158 CONTENTS. CHAP. VII. The Phytophagous Gastropods continued. — The Turbidae, or Marine Snails - - - ... page 195 CHAP. VIII. The PhytophagouslGastropods concluded. — The Haliotida?, or Ear-Shells, and the Naticida?, or Nerits - - - 228 CHAP. IX. On the Aberrant Tribes of the Gasteropoda, — namely, the ,Scutibranchia, or Limpets ; the Cyclobranchia, or Chitons ; and the Pteropoda, or Crystal- Shells - - - 241 CHAP. X. On the Order Dithyra, or Bivalve Shells. — The Affinities and Analogies of the Unionidae, or River Unios - - - - 253 PART II. A NATURAL ARRANGEMENT OF THE UNIVALVE AND BI- VALVE SHELL-FJSH COMPOSING THE ORDERS GASTERO- PODA AND DITHYRA OF THE CLASS TESTACEA - 2Q5 EXPLANATION OF TERMS USED IN DESCRIBING THE SHELLS OF TESTACEOUS MOLLUSC A - 39 1 APPENDIX - - - 405 A TREATISE ON MALACOLOGY; SHELLS AND SHELL-FISH. PART I. A GENERAL SURVEY OF THE TESTACEOUS MOLLUSCA. CHAPTER I. INTRODUCTORY OBSERVATIONS. THE MOLLUSCA IN GENERAL. THE CHARACTERS AND ANALOGIES OF THE THREE PRI- MARY DIVISIONS OR CLASSES; NAMELY, THE ACRITA, THE RADIATA, AND THE TESTACEA. NOTES ON THE BIBLIOGRAPHY AND THE EXISTING CLASSIFICATIONS OF THE LATTER. (1.) IN our last volume, we completed the survey of those great divisions of animals which, from possessing a 'bony skeleton, are called the VERTEBBATA. Our pre- sent treatise will be devoted to a far more numerous, but less interesting, assemblage, — namely, the MOLLUSCA, or soft animals. These, with few exceptions, are either inhabitants of the ocean or of fresh waters. The majority are little known even to naturalists ; and B SHsEIvLS-AND SHELL-FISH. PART i' Q^r^rea^le,v& rtiky pass their lives without ^seeing ^ bite; say el: ihfic'siug? in their gardens, or the empty shells they once inhabited. Their aspect to the ordinary observer is strange and unprepossessing, with- out either the gracefulness of form, the activity of motion, or the richness of colouring which ornaments insects and vertebrated animals. Their manners and economy scarcely come within our cognisance, for their actions are carried on in an element we do not in- habit ; hence they are rarely witnessed, and a few partial details is all that has yet been gathered to eluci- date their history. Their soft and slimy bodies cannot be preserved so as to interest us even by their appear- ance, or to become objects of beauty or of popular interest ; they are, in short, almost passed, " unheeded and unknown," except by the eye of Science. (2.) The object of the series of volumes we are now producing, is, to give to the world what has never yet been attempted, — a philosophic survey of the works of nature, based upon the harmonious relations which every part bears to the whole. Partial systems, ap- plicable to one branch only, and a crowd of anatomical facts, have been either omitted, or but slightly touched upon, as mere accessory helps to the paramount object of our labours. We have, indeed, got through the almost herculean task of arranging the whole of the Vertebrata according to their natural affinities and rela- tions, even down to the sub-genera ; but to follow up this plan with the annulose and the molluscous animals, would not only swell the Cabinet of Natural History to three times it prescribed limits, but would demand a knowledge which, individually, would be superhuman. The great truths, or, rather, the leading one, which the enlightened reader should have constantly brought before him is, the UNITY OP PLAN in the creation : this might be lost sight of, if the attention was long withdrawn from such enlarged conceptions, and occupied by a mul- tiplicity of small details, fit only for the technical de- scriber and the anatomical demonstrator. CHAP. I. PLAN OF THE WORK. 3 (3.) Under all these circumstances, we must therefore treat the molluscous groups with great brevity : the lead- ing divisions, indeed, of the 'whole will be briefly stated, sufficient to guide the researches of those who may be disposed to adopt our views of natural arrangement, and to analyse their contents ; but this will be entirely subordinate to the primary intention of this volume, which, it will be seen, is almost exclusively confined to the TESTACEA. Limited as is our space, we shall endeavour to fill it in that way which promises to be of the greatest permanent, as well as practical, advantage to science. The arrangement of one class of the Mol- lusca, founded upon analysis, is obviously more valu- able than a theoretical digest of the whole. We are seeking to place zoology upon a new basis. To discover and develope, as far as in us lies, the fundamental prin- ciples of the natural system ; and to exhibit its compo- nent parts — not as detached portions, as if each had its own set of laws and its own little system of arrange- ment, but — as a vast and connected whole, throughout which the utmost harmony and the most perfect unity of plan pervades. To do this, however, with any degree of success, requires a fulness of detail, insepa- rably connected with the comprehensiveness of the subject, and the novelty of the design. It is due, not only to the scientific public, but to the labours of those great men whose opinions now reign paramount, that the systems now in use should not be lightly set aside. Hence a variety of details, unnecessary under other circumstances, becomes absolutely essential in these. Now, of the three classes of molluscous animals, the TESTACEA, or shell-fish,, is that which possesses the greatest degree of popular, and even of scientific, in- terest. Their beautiful shelly habitations form some of the most interesting objects in our public museums and private collections. And although we should not consider ourselves bound to make this the only reason for a neglect of the other classes of the Mollusca, yet, under existing circumstances, we shall so far concede to 4 SHELLS AND SHELL-FISH. PART I. popular taste, as to devote our present volume almost entirely to so favourite a branch. This plan will enable us to submit nearly the whole of our investigations to the public ; while we trust to do the same hereafter in re- gard to the remaining classes in a separate publication. (4.) The innumerable groups of beings which we comprehend under the general name of Mollusca, are at once distinguishable from all other animals, by having no internal bones,, like the Vertebrata ; or no joints to their body and limbs, like the Annulosa, or insect tribes. In the first, the skeleton is internal ; in the latter, it is ex- ternal ; but, in the Mottusca, it is entirely wanting. We might fill several pages on these anatomical dis- tinctions ; but simplicity is the soul of instruction ; and we feel assured, that in following this rule, in the pre- sent instance, we are saving the unscientific reader a world of perplexing circumlocution. (5.) We shall first glance at those characters drawn from the nervous system, which, it is thought, sepa- rate the Mollusca from the Vertebrata and the Annulosa. On a former occasion *, we have stated that their nerv- ous system is variable; and that this variation pointed out the secondary divisions or classes, under which the leading zoologists of the age have, almost unanimously, arranged them. Thus, in the ACRITA, or polypes, the nervous system has been called granular; these granules, innumerable and minute, being generally dispersed over the bodies of these animals, which resemble " masses of transparent, homogeneous, mobile, and sensible pulp, and thus impregnating the whole with sensibility. "t In * Classification of Quadrupeds, p. 37. f Such, at least, is the definition of the ACRITA of MacLeay; but our recent researches among ftie Mollusca induce us strongly to doubt the propriety of placing therein the greater part of those minute animals which that celebrated naturalist has arranged with the corals. Our present im- pression is, that the whole, or nearly so, of the true ACRITA, are com- pound zoophytes, or, in other words, plant-like animals ; that the Ro- tifera and Infusoria are only prototypes of the Acrita in the circle of the Radiata ; and that the annulose intestinal worms are the same among the Annulosa. As for the Parenchymata, it will be seen we have had no hesitation in placing them as the representatives of this class in the most aberrant order of the testaceous Mollusca. We feel, in short, more and more persuaded that the real contents of the order Cyclobranchia cannot be determined until the entire class of ACRITA has been sufficiently ana. CHAP. I. PRIMARY DIVISIONS OF MOLLUSKS. 5 the second class, or the RADIATA, the nerves are ar- ranged in a radiated or star-like manner; while in the testaceous Mollusca, or TESTACEA, the nervous system resides in four ganglions, either united in pairs, or altogether, which are embraced by a medullary collar. (6.) It would thus appear that the three great divisions of MOLLUSCA are as much distinguished by their ana- tomical peculiarities, drawn from then- nervous system, as they are by their external and more obvious cha- racters. It is by these latter, however, that they are made intelligible to the generality of readers. Every one, therefore, will be at no loss to understand the ex- ternal distinctions of these primary divisions : 1. The TESTACEA, or shell mollusks ; 2. The RADIATA, or radiated mollusks ; and, 3. The ACRITA, or polypes. The first being represented by shell-fish ; the second, by starfish, sea eggs, and medusas j and the third, by corals, polypes, and other plant-like animals. We shall now, in the first place, point out the manner of their con- nection to the higher classes of animals, with the ohject of showing that they form an integral part of that vast circle which comprehends the whole of the animal world. (7.) The primary distinction of vertebrated animals is, their being possessed both of an internal column, or back-bone, and of legs or other members which give them the power of locomotion : it follows, therefore, that if we found among the soft Mollusca any animals which really possessed these characters, however slightly de- veloped, we should consider them as forming the pas- sage from one class to the other ; that is, from the Ver- tebrata to the Mollusca. Now, there is a whole tribe of animals which really present us with such a struc- ture, and yet, in all other respects, they are so unlike the Vertebrata, that every writer places them with the lysed. Between the Dorida and the Branchiopoda, there must be, or have been, very many intervening forms : and we begin to think that Cuvier may not be very wrong in placing many, if not all, of his naked Acephala close to the Branchiopoda. But the analysis of the ACRITA can alone de- termine this question. B 3 6 SHELLS AND SHELL-FISH. PART I. Testacea. This tribe is the Cephalopoda, or cuttlefish. It is among these only, out of the whole class of Mol- lusca, that we find a distinct, and often rigid,, hack-hone, — not, indeed, jointed or articulated, hut performing the same office as the vertehrated column of a quadruped or a hird : others of its class have no limbs whatever ; but the cuttlefish have immense arms, which are also used as legs ; by these they crawl with the greatest facility on the bottom of the sea, swim quickly in the water, and retain the most forcible hold of such ani- mals as they prey upon. The eyes of nearly all Mol- lusca are either small and indistinct, or are entirely wanting; in these, however, the eye is large, and as fully developed as in any vertebrated animal. There cannot, therefore, be the least doubt of the close ap- proximation of the Cephalopoda to the Vertebrata ; and as a large proportion of the fossil species were fur- nished with spiral shells, it follows that the testaceous class comes immediately after the Vertebrata. This affinity being established, we are at no loss to discover the point of junction between this and the next class, or the Acrita. The singular naked animals forming the Nudibranchia of Cuvier, have been very properly placed by many authors close to the tunicated polypes (Tunicatd). Again, on the other side of the circle of Acrita, we have the genus Zoanthus and the Polypes charnues of the French writers, closely connected to the RADIATA by Priapulis and other kindred forms ; while the last vestige of the radiated structure is seen in the Cirripeda : these latter animals, however, by their arti- culated limbs, are yet removed out of the confines of the Radiata, although they become the first group in the Annulosa, — thus standing in precisely the same re- lation as the Cephalopoda do to the Vertebrata. We have now traced the chain of affinity into the annulose, or insect class ; and it only remains to inquire how these latter are connected to the Vertebrata, or, in other words, how the animal circle is made out and closed. On this point, again, the labours of our predecessors CHAP. I. RANK OF THE TESTACEA. 7 have removed all difficulty,, and even doubt. The Anne- lides have the joints of their bodies, like the common earth-worm, disposed in rings, but yet they offer the extraordinary character of red instead of white blood : hence, they are always called red-blooded worms. There is, to be sure, no vestige of any internal support to the body, such as we have seen in the Cephalopoda ; but every one must be struck with the resemblance which exists between a worm and an eel, — the one being, in form, almost the miniature of the other. This re- semblance, moreover, is carried much further by certain eel-shaped fishes, which are destitute, not only of fins, but of eyes ; while in others, as the genus Myxine, the vertebral column, or back-bone, is hardly to be dis- tinguished. It is impossible, therefore, for this grad- ation to be more perfect. Every naturalist of the least repute has viewed the connection of the Anne- lides to the fishes in this light j and thus are all the classes of the animal kingdom united into one vast circle. (8.) Of the three divisions of the Mollusca, — namely, the Testacea, the Radiata, and the Acrita, — it is obvious that the latter are the lowest in the scale of animal life ; the superiority of the Testacea to the Radiata must also be admitted, when we come to compare the or- ganisation of one with the other. The shells of the Echinidce, the most typical group of the radiated animals, are certainly as beautiful and complicated in their con- struction — although not, perhaps, in outward appear- ance— as those of the Testacea; but we must look to the animals themselves. The Echinida show not the least indication of that form which belongs to verte- brated animals : although provided with short tentacula, which are supposed to assist them in removing from place to place, they yet move so slowly, that a snail, in comparison, may be said to run : thus the Echinus., al- though with tentacula, — which are supposed to perform the office of feet, — can scarcely remove itself a few ijichesj the snail, which has no foot or similar processes, B 4 SHELLS AND SHELL-FISH. TART I. crawls on its belly, at what, in comparison,, is a good round pace. The typical Testacea are all provided with eyes, however small, and with feelers ; but the Echinidce have none, properly so called ; they are, in fact, de- cidedly lower in the scale of creation than the shell- fish ; for, while the whole of the Radiata are destitute of eyes, those of the Testacea, in the pre-eminently typical division (the Zoophaga), and of the Cephalopoda, are generally very perfect, and always present. This accords exactly with what, from theory, we should have supposed : that the Testacea, being nearest allied to the typical Vertebrata, would consequently be more perfectly organised ; while the Radiata, being cut off, as it were, from the Vertebrata, by the intervention of the Annu- losa, become further removed from the great types of animal perfection, and, consequently, exhibit an inferior developement. The Testacea are, therefore, the most perfect of all the MOLLUSCA. (9.) Having now indicated, although with more brevity that we could have wished, the relative station of the testaceous Mollusca, both in regard to other animals and their own class, we shall direct our chief attention to the exposition of their natural and circular arrangement. Although we so far concede to the popular taste for conchology (as the " art " of arranging shells and other testaceous bodies is called) as to devote this volume exclusively to the testaceous Mollusca, we can- not sacrifice our conviction on the principles upon which these animals should be studied, or fall into the common method now in use of writing upon shells, independent of all consideration for the animals by which they are inhabited. To dignify any pursuit of this kind by the name of Science, seems to us quite misplaced ; since it would be hardly more absurd to classify birds by the colour of their eggs, or beetles by the shape of their wings, than to propound an arrangement of shells, with- out a paramount regard to the animals which they cover. It is quite right that collectors of these elegant objects, who mix up with them shelly cases of insects CHAP. I. HEMARKS OX CONCHOLOGY. iJ (Cirripedes) fragments of worms (Annelides), hack- bones of cuttlefish, gill covers of sea hares (Apfysia), &c., should arrange them in their cabinets upon some plan,, arid give them names ; but no one will maintain that this amusement deserves to be called science. (10.) One of the first zoologists of this country, in speaking of the utter ignorance which exists on the natural arrangement of the Testacea, and the high importance that belongs to the inquiry, makes the fol- lowing remarks : — " At all events, it is not to those collectors who are solely intent on the external form of a shell, or the streaks of colour which ornament it, that the hope of discovering the true arrangement of the Mol- lusca can be held forth. The study of shells appears, indeed, to be indispensably necessary to the geologist; and, no doubt, the testaceous covering of an animal is always so intimately connected with its structure, that it would be unpardonable in the naturalist, who ought to leave nothing without investigation, to forget shells. But, on the other hand, when we call to our recollection the lamentable error committed by Linnaeus and his disciples, in not following the example of our celebrated Lister in the arrangement of the Mollusca, we be- come convinced there was about as much hope of their ever arriving at the truth by the means they chose to adopt, as that a collection of the wings of different in- sects should ever instruct us fully in the natural history of the animals to which they belong. It is said that Klein formed an ornithological cabinet, in which the feet and beaks of birds were only to be seen ; because, according to his notions, they were all the parts re- quisite for the proper arrangement of the feathered creation. He thought that it was possible to be a good ornithologist, without knowing the least of a bird but its beak and claw. We may, indeed, laugh at this ; but, at the same time, we ought to inquire whether similar ridicule may not, with justice, be extended to those conchologists, who, having procured a shell, describe and classify it without deigning to bestow a single thought 10 SHELLS AND SHELL-FISH. PART J. on the nature of the poor animal which constructed it for its habitation.* A curious arrangement, as might have been expected, has come of this method of pro- ceeding ; for we have annulose animals f (or insects) united to true Mollusca, merely because they have shells; and true Mollusca separated from this division, merely because they have no shells. In some cases,, even, as in the genus Limax, it is sufficient for the shell to be small, in order to set it wide asunder from animals of the same family : but it would be endless, as well as useless, to detail the violations of natural order mani- fested by Linnaeus in his systematic arrangement of the mollusks, which have so truly constituted his stum- bling block. It cannot, however, be denied, that, could we adopt his notion as to the nature of the animals, the principles upon which he arranged their testaceous co- verings are excellent. To those who admire the splen- dour of the pencilling, the beauty of the enamel, and the variety of sculpture, which exist in shells, it might be depriving them of an innocent amusement, to object the trivial nature of their study as leading to no general results ; but it may be as well to remind them, that, unless they add to their satisfaction and to their know- ledge by studying the structure of the animals them- selves, there is no more science in the disposition of their cabinets, than may appear in the tasteful arrange- * A modern compiler, who has been at some pains to draw up what he considers some general observations on the " Principles of Conchology," very properly refrains from bestowing upon it the name of a science. " Conchology," as he observes, " is the art of arranging the protecting bodies of testaceous " (and he might have added of annulose) " animals, so as to enable us to recognise them promptly and certainly, without giving any attention to the animals which they have contained, or contain, or, at least, regarding this part as a matter of very minor importance " Inde- pendent of the assistance this " art " bestows to the studies of the geologist, he further observes, " it may almost be regarded as a study nearly idle and useless by all true zoologists." Nay, he continues, " it is really to this cause that Conchology, properly so called, owes both the continuance of its existence, and the daily increasing efforts of enlightened naturalists, who endeavour to give it sure principles and rules." He omits to inform us, however, how these sure principles and rules can be attained in an " art " which absolutely rejects that solid foundation for them, upon which their true knowledge depends, — that is, a primary regard to the principles of the variation in these animals. f The Cirripedes, or barnacles. CHAP. I. REMARKS ON CONCHOLOGY. 1 1 ment of porcelain on a mantelpiece. Separate the shell from the animal, and much less acquaintance with the natural system is to be derived from their inorganic covering, than Klein obtained of his birds, by seeing only their beaks and claws." * (11.) The above sentiments on the insufficiency of the shell, in all cases, to determine its place in the natural system, we are free to confess, were held by us for many years. But the results of that analysis now given to the public, have materially modified, if not altered, this opinion. It is needless, perhaps, to repeat, that a primary regard must always be had to the nature of the mollusk itself ; and that, without this knowledge, there are certain forms of Testacea, of which neither their natural tribes nor families can be conjectured, and which, for this reason, should always be kept apart. There are others, again, belonging to totally different families, or even orders, which are so alike in their shells, that conchologists place them in juxta-position.t But yet, on the other hand, there are numerous other families, where the modifications in the form of the shell are just as im- portant, and even more so, than those of the animal. The molluscous system of Poli fully establishes this proposition, even though the innumerable proofs in its support, hereafter detailed, were rejected. The truth appears to be, that Nature, on the whole, has diversified the external aspect of these singular animals, — that is, their shells, — much more than she has their soft or more unsightly parts. If, therefore, she has thus bestowed all her beautiful embellishment upon the habitation rather than upon the inhabitant, we may at least con- clude that the one is as essential to develope the plan she has pursued in her own system, as is the other. The diversity she has created on the shelly coverings of the typical Testacea is, beyond all comparison, greater * Hor. Entotn. p 240—244. t Particularly the prototypes of the Planaridce, as Fttrina. Sigaretus, Chaelinotus, &c. 12 SHELLS AND SHELL-FISH. PART I. than is to be found among their animals ; but these latter must be well studied, before we can comprehend the leading types of form prevalent among the former. When this last discovery, if only in part, has been made, we shall find that the slightest modification in the shell is not without its meaning; and that, in nine instances out of ten, we may pronounce with as much confidence on its natural station in the scale of nature, as if we had actually dissected its animal. (12.) A singular idea appears to be entertained by some writers, that the " art " of conchology, popularly so called, is only really serviceable to science, when viewed in connection with geology. But it may fairly be asked, how geology or any other branch of knowledge can be benefited by any aid which is not, in itself, built on sound and philosophic principles, which this t( art " confessedly is not. It would be difficult to answer the question why one branch of zoology is to be separated from the others, and degraded into the hand- maiden of another science, — and that, too, of such very recent formation, that the most opposite opinions as to its very first principles are continually issuing from the press. It is not a little singular, also, that, while geologists appear to attach so much importance to mineral conchology, as it is termed, no author, as yet, has specifically written on the subject. In such a state of things, the attempts that are made to identify certain strata by the nature of the shells they may contain, should be ventured upon, in most cases, with very great cau- tion. We are fully persuaded that many of those fossil shells termed by conchologists fluviatile, are decidedly marine ; that the nature of others, from ignorance of their animals, can never be understood ; and that a great number, now considered identical with existing genera, belong to groups altogether extinct. Until, therefore, all these suspicious points are cleared up, geologists will derive but very little comparative benefit by our modern systems of conchology, and will be fre- quently led to most erroneous conclusions. The " art," CHAP. I. BIBLIOGRAPHY OF MALACOLOGY. 13 in fact, must merge into the science of MALACOLOGY, in which equal regard is paid both to the animal and the shell. 1 1 is then alone that geology will be really benefited. Our science will then repose upon a proper and philosophic basis, and in that capacity will be ready to aid those of her sisters who may solicit her services. (13.) Our notices on the BIBLIOGRAPHY of the tes- taceous Mollusca, must be very brief, and chiefly con- fined to such as have a practical influence on the present state of science. This brevity will be the less regretted, since the subject has been so ably and fully gone into by Maton and Racket, in the seventh volume of the Linncean Transactions. The foundation of this and every branch of zoological science was laid by the im- mortal Aristotle, who well discriminated all the leading groups of the typical Testacea, and was not inattentive to the habits and localities of the animal inhabitants. He separated the spiral univalves by the name of Mo- nothyra, while he applied the term of Dithyra to the bi- valves. It would have been as well if the moderns, in their multifarious and complicated nomenclature, had shown some little respect to the designations imposed by this commanding genius on the leading groups of the Mol- lusca ; such defence would, at all events, have brought his name more frequently before us, and reminded the world how infinitely science was indebted to his labours. How much superior, also, is the simplicity of genuine classic names over those compounded in modern times, will be best seen by comparing those bestowed upon the bivalves, which are the Dithyra of Aristotle, and the Malacozoaria Acephalophora of M. de Blainville. It is too late, perhaps, to restore the entire nomen- clature of the illustrious Stagyrite ; but in this single instance we shall certainly prefer his designation of the bivalve Mollusca in preference to those of the moderns.* * The term of Acephala, given by Cuvier, would be by no means objec- tionable, but that it sets aside the name of antiquity, and includes, more- over, numerous groups which have nothing in common with the Dithyra of Aristotle, except the want of a distinct head. To judge, indeed, from the writings and nomenclature of the French school, it would hardly be conjectured that such a man as Aristotle had ever existed. 14 SHELLS AND SHELL-FISH. PART 1. (14.) Our celebrated countryman, Lister*, was the first naturalist, after the revival of learning, who made any decided improvement in this science, since he re- garded both the animals and the shells ; and his noble volume will be an imperishable record, both of his talents and his industry. The excellent figures of Rumphiust, published in 1711, are still valuable, as are likewise those of Gualtieri J, but neither of these writers can scarcely be said to have benefited the subject in any other way. D'Argenville's plates, although more elaborately finished, are very inferior to those of the last-named works ; and it has been truly said, that what is really valuable in his book has been taken from Lister. The conchological labours of Klein, who was perpetually writing upon every branch of natural his- tory, partake of the character which belongs to all, — a total want of genius. It was, in fact, reserved for Adanson§, the celebrated French traveller and naturalist, once more to revive malacology from the frivolous state into which it had been gradually sinking since the days of Lister : by studying both the animal and its shell, he prosecuted his researches on sound and philosophic principles ; and hence it is, that his volume, although published in 1757, is highly valuable, while the " tes- taceous " arrangement of Linnaeus is as if it had never been written, — or it is consulted only, at rare intervals, to determine a specific name. But Adanson confined himself to the shell-fish of Senegal ; and it was not sur- prising that the scientific world, captivated by the sim- plicity of the Linnsean nomenclature, still continued attached to the plan of considering the Testacea merely in regard to their shells, of which innumerable species now began to pour in on the European cabinets. This, * LISTER. Historia, sive Synopsis Methodica Conchyliomm. London, one volume, folio ; of which there are two editions, the last in two volumes. See Prel. Discourse, p. 24. t RUMPHIUS, G. E. Thesaurus Imaginum Piscium,, Testaceorum, &c. Hagae Comitum, 1739, folio. J Nico. GUALTERI. Index Testarum Conchyliorum. Flor. 1742, royal folio. The figures are the most artistical of any that we remember: the rotundity of the spiral shells is admirably represented. $ Hist. Nat. des Coquillages du Senegal. Paris, 1757, 4to. CHAP. I. BIBLIOGRAPHY OF MALACOLOGY. 15 doubtless, gave rise to the voluminous work of Martini and Chemnitz, which, although published between 1769 and 1788, and with figures exceedingly ill drawn, is, nevertheless, the most valuable, as a general work, we yet possess. It was soon after this time, however, that George Humphrey*, F.L.S., the chief commercial conchologist then living, gave to the world a small pamphlet, wherein he arranged the Testacea upon an entirely novel and very remarkable plan. As a system of conchology, this was both a sudden and a most extensive improvement upon everything of the kind which had hitherto been done. The arrangement, which will be subsequently adverted to, as far excels that of Linnaeus, as Lister's exceeds that of Klein. There can be no doubt, in fact, that this little unpre- tending pamphlet, published in this country merely as an exhibition catalogue, found its way to France, and served as the main foundation, although unacknow- ledged, for the subsequent system of Bruguiere, if not of Lamarck and Cuvier. It was, to write colloquially,, the first quiet but thorough breaking of the ice, in which conchologists were bound up by the Linnaean system ; and those who followed up the reformation, however justly we may praise them as improvers, can- not be invested with the more honourable distinction - of leaders. It was, therefore, not in France, but in England, that the revolution against the meagre concho- logical school of Linnaeus first originated. But, having said this, we can put forth no claims for our countrymen, on this head, during a subsequent period of nearly forty years. Montagu, indeed, must be named with honour, and Pennant's writings aided much to spread a taste for collecting shells ; but beyond these, we recollect no others deserving special record. Meantime, a more correct knowledge of the molluscous animals was making rapid progress on the Continent. Those illustrious and ad- mirable anatomists, Poll in Italy, and Cuvier in France, * Museum Calonnianum. — Specification of the various Articles which compose the magnificent Museum of Natural History, collected by M. de Calonne in France. Anonymous, London, May 1. 1797. 16' SHELLS AND SHELL-FISH. PART I. were prosecuting their researches with indefatigable industry ; while Bruguiere, and subsequently Lamarck, were no less occupied in describing and arranging the Testacea; meantime, faint attempts, in the shape of In- troductions, to keep alive Linnaean conchology, were all that appeared in England on this subject. The labours of Bruguiere were unfortunately terminated prematurely by death, but those of his illustrious friend Lamarck were continued up to within these few years. His masterly and incomparable work, wherein all his labours on the invertebrated animals are concentrated, are too well known to be expatiated upon in this place, since it is in the hands, or should be, of almost every zoologist who studies those classes. The investigations of Poli, even more elaborate than those of Cuvier, have been given to the world more slowly, and in such an expen- sive form, as to deprive them of half their utility.* Not so with those of the celebrated Cuvier. The Regne Animal, a book accessible to all purchasers, con- tains the essence of all his labours on the Mollusca, but, unfortunately, so much abridged, that the student is frequently more perplexed, than satisfied, on the point he is searching for. His more detailed memoirs are scattered through innumerable volumes of foreign transactions, where they lie completely hidden from e very-day reference, although their intrinsic and per- manent value would fully warrant their being collected and printed in a cheap volume.t In estimating the merits of these three great men, — Poli, Cuvier, and La- marck,— in regard to their arrangement of the testaceous Mottusca, it may be stated, that the first confined his system entirely to the animal, giving to it a different name to that of the shell; so that, if the animals of two conchological genera (as Avicula and Lima) were nearly * POLL Testacea Utriusque Sicilia?, eorumque Historia et Anatomia, £ vols. royal folio. Parmae, 1790—5. A Supplement, by Stephanus della Chiaje, forming another volume, was published at Naples in 1833. f A few copies of these Memoires, with their plates, were struck off se- parately, and published in one 4to. volume, Paris, 1817 ; but this is now become so rare as to be unprocurable, excepting by chance. CHAP. I. RECENT WORKS. 1 7 alike, they were placed, in his system, in one and the same genus. Cuvier has altogether avoided this strange mode of procedure ; hut an inspection of his system will hear us out, we think, in our opinion that he has placed far too great a stress on the modes of respiration, and paid too little attention to the shell, no less than to the animal ; while the great error of Lamarck appears to have been that of giving to the shell, and more espe- cially the hinge of bivalves, a greater regard than he bestows upon the animal. The system of M. de Blain- ville, indeed, professes to remedy these defects ; but we can discern in it little that is new, beyond innumerable compound Greek names, proposed for groups already established by his predecessors, and which are only calculated to overturn all existing nomenclature, with- out adding anything practical to the advance of science. (15.) Whatever may be the cause, certain it is that nearly all that is now valuable in malacology has emanated from the Continental naturalists. Besides those just enumerated, the unwearied zeal of the French circumnavigating naturalists, more especially M. Quoy, has added to this science not merely a host of new shells, but — what is far more valuable — innumerable facts, of the highest importance, regarding their animals. We only regret that the price of these splendid publica- tions, and the few copies of them yet in this country, have prevented us, in all instances, from profiting from these most valuable materials. The only one of our country- men who has pursued the same path of inquiry, and on the same philosophic principles, was our late friend, the Reverend Lansdown Guilding, who, from his official residence in the West Indies, had the enviable opportunity of examining, and the rarely united talents of drawing, dissecting, and describing, the soft Mollusca of the Caribbean seas. To him is science indebted for a knowledge of the animals of numerous terrestrial and many marine shells ; and the institution, on the most solid basis, of several natural genera. These invaluable researches, too little appreciated by our conchologists, c 18 SHELLS AND SHELL-FISH. PART I. in their zeal for describing new species, and too little known to the scientific world, from heing scattered in detached papers, or unpublished, are all incorporated and acknowledged in this volume.* To this accom- plished zoologist and exquisite artist are we indebted, among many other things, for the discovery of the extraordinary genus Herpa ; and for drawings of the animals of Oliva, Volutella, Marginella, Triton, and Trochella; as also of several other groups, originally characterised from the shells alone, but now confirmed by the difference of their animals. The name of Mr. Lowe, the natural historian of Madeira, deserves honourable mention in this place, as connected with the illustration of many interesting facts on the Mollusca of that island. A most magnificent, but extravagantly expensive, work on the land and freshwater shells, was commenced, several years ago, by the late baron de Ferussac.t As it was patronised by Royalty, some hopes were entertained of its completion, notwithstanding the grand scale it set out upon ; but the undertaking was evidently too vast for the very moderate abilities of its projector ; the parts came out less and less regularly, until, after it had cost the subscribers near 50/., it was (virtually) given up, and the author died. This striking example is surely sufficient to convince any sober judging person of the utter impracticability of completing a General Conchology, or of carrying it on beyond a few numbers. It is, in fact, a physical impossibility for any one or five men to accomplish such a work in the ordinary term of human life ; and even if brought to a termination, unless conducted on the most economic scale, would involve an outlay to the projectors, and an expense to the public, which the latter, at least, would never incur. We are, in truth, heartily set against all these magnificent under- takings : they are absolutely detrimental to science ; * A large collection of highly finished drawings, and several MSS., are now in the possession of Mr. Guilding's late widow. t FERUSSAC. Hist. Nat. gen£rale et particulidre des Mollusques Ter- restres et Fluviatiles, 27 parts, published, Paris, 1819—33. CHAP. I. SYSTEMS AND ARRANGEMENTS. 19 for they confine the materials of knowledge and of study within the narrow limits of the select few (gene- rally wealthy amateurs),, to the exclusion of all who cannot expend 400/. or 500/. upon a zoological library. We cannot but admire the zeal of their projectors, — for such works never produce profit, and generally bring a heavy loss, — but we think it a zeal misplaced. What is now most wanted, is a collection of plates of shells, to supply the deficiencies of the series in the Tableau Encyclopedique et Methodique *, and printed uniformly. The series in question contains nearly 300 plates, and is the very best which the naturalist can possess. We have constantly referred to it, as being more within the pecuniary reach of the student, and as being far more accurate in the figures, although uncoloured, than that of Martini and Chemnitz ; and these latter are there- fore only quoted for species not contained in the other. The figures in Wood's Catalogue are often very good ; but the arrangement is so confused, and often so erro- neous, that the nomenclature, in its present state, can seldom be quoted as an authority. (16.) In regard to SYSTEMS and ARRANGEMENTS of the testaceous animals, the only attempt that has ever yet been made towards the natural disposition of this extensive class, is that indicated in the Hora Ento- mologicte. The ingenious author, however, candidly acknowledges his inability even to point out the primary divisions; although he has ventured, and, as we think, has partially succeeded, in tracing the links of affinity by which the testaceous Mollusca are connected, on one side, to the Acrita, or polypes, and, on the other, to the vertebrated animals, by means of the Cephalopoda. Of arrangements made without any ulterior object of illustrating the general harmonies of nature, and there- fore artificial t, there are several ; the best being those * With these plates, and Lamarck's volumes of the Hist. Nat. des Am- maux sans Vertcbres, the conchologist will be at no loss to arrange an ordinary collection of shells, and name by far the greater portion of the species. The excellent Manuel de I' Hist. Nat. des Mollusgues of M. Sander Rang should also be procured, on account of the valuable notices it con- tains on the structure of the animals. f See Geography and Classification of Animals, p. 125. C 2 20 SHELLS AND SHELL-FISH. PART I. of Humphrey, Lamarck, and Cuvier. The two first of these will therefore be exhibited in their details ; the latter having already been placed before the reader in a former volume. Although that of Lamarck,, by common consent, has been preferred by nearly all zoo- logists, it is but justice to the distinguished author of the Regne Animal, to designate his early Memoires upon these animals as fully entitling him to the high reputation his anatomical talents have so justly acquired for him in other departments. They are materials upon which all true knowledge of the Testacea must repose. (17.) The conchological arrangement of Humphrey, already spoken of, will now be detailed, so far, at least, as regards the names of the genera ; since their de- finitions were never published. To show how intimately very many of these accord with those of Lamarck, we have, in almost every instance, added the corresponding genus of the latter. The ingenious author had such a conviction that the fluviatile and terrestrial genera should be kept distinct from the marine, that he places them in separate divisions. * CLASS TESTACEA. ORDER I. MARINE. DIVISION I. UNIVALVES. Conus L. Serpula Linn. Melo. Broderip. Dentalium L. Voluta L. Patella L. Musica. Voluta Lam, Larva. Fissurella Lam. Harpa. Lam. Crypta. Crepidula Lam. Doliunu Lam. Calyptra. Idem Lam. Casida. Lam. Galerus. Calyptraea Lam. Haliotis L. Pedum. Spirula Lam. Haliotoklea. Stomatia Lam. Nautilus L. Auris Veneris. Sigaretus Lam, Argon auta L. Bulla L. Neritoidea. t lanthina, &c. I Lam. Licium. Cypraea L. Ovula Lam. Uber. 7 Lunatus. J Natica Lam. Dactylus. Marginella Lam. Nerita L. Oliva L. Auris Mustelae. Tornatella Lam. . * The author, with that modesty which was his peculiar characteristic, thus expresses himself: — "The editor hopes that his confession of being but little acquainted with the learned languages will be received as an apology for such improprieties in the generic orspecific names as he fear* will be found."— Museum Calonneanum, pref. p. v. CHAP. I. SYSTEM OF HUMPHREY. Turbo L. Strombus. Pterocera Lam. Eutropia. Scala. PhasianellaLam. Scalaria Lam. Triplex. 1 Purpura. 3 Murex Linn. Terebra. Lam. Rheda. Hyalia Lam. Obeliscus. Trochus Linn. f Cidaris Sw. Drv. IL BIVALVES. " I Marmarostoma. Pinna L. Senectus. Sw. Mytilus L. Elenchus. Sw. Solen L. Physeter. Solarium Lam. Margaritifera. Avicula Lam. Apiculum. Trochus Lam. Vulsella. Lam. Trochulus. > Trochus. 3 Monodon Lam. Placuna. Cepa. Lam. Anomia Linn. Sol. Tubicanthus Sw. Lam pus. Terebratulaiowz. Onustus. Pygma»a. Sw. Columbella Lam. MactraZ.. •> Trigonella.j Mactra Linn. Pyrum. Pyrula Lam. Tellina L. Haustrum. Purpura Lam. Cuneus. Donax Linn. Hystrix. Riciuula Lam. Pectunculus. Venus Linn. Bulbuj. Rapella Sw. Cardium L. Acus. Terebra Lam. Trapezium. Chama Linn. Clava. Cerithiuin Lam. Tridacna. Lam. Cassidula. 7 Ficus. 3 Pyrula Lam. Glycymeris. Area L. Lam. Rhombus. Fusus, &c. Lam. Pecten. Lam. Rana. Ranella Lam. Ostrea L. Buccinum. Triton, &c. Lam. Lacinia. Chama Lam. Turris. Turritella Lam. Spondylus L. Colus. > Fusus. 3 Fusus Lam. DlV. III. MULTIVALVES. C Fusus Lam. Pholas L. Cuma. i Fasciolaria Ib. Lepas L. Mitra. Lam. Cornucopia. Lepas Linn. Murex. Scolymus Sw. Balanus. Rapum. Turbinella Lam. Chiton L. Alatus. Strombus Linn. ORDER II. FLUVIATILE. Div. L UNIVALVES. Div. IL BIVALVES. Catillus. i Neritella. j Neritella Lam. Barbata. Scapha. Unio Lam. Iridina? Lam. Pomus. Ampullaria Lam. Mya. Unio Lam. Vesica. C Lymnia. i. Melania Lam. Nux. Capsa. Cyclas Lam. Ligula. 1 Turricula. 3 Melania Lam. ORDER III. TERRESTRIAL. Sylvicola. Cyclostoma Lam. Otis. Auricula Lam. Helix L. Chersina. Achatina Lam. Lituus. Cistula. Cyclostoma ?Lam . Cyclostoma. Lendix. 1 Pupa. 3 Pupa Lam. Bombyx. ? 22 . SHELLS AND SHELL-FISH. .PART I. (18.) As a purely conchological system, this was un- questionably the best and the most original of any that had appeared since the revival of learning. It was pub- lished in 1797, nearly twenty years before the first of Lamarck's volumes appeared. * That it was well known to the latter can hardly be doubted, when we see no less than ten genera similarly named by both ; and that almost every genus of Lamarck's univalves are found in this list, under different, but less classical, names. Of univalves, Humphrey has 87, contained in the single collection of which his book is a catalogue. How many more he had determined to name, does not, of course, appear ; but the total number of Lamarck's is but 96, for the whole of the testaceous gastropods. (19.) Lamarck's system, so far as regards the animals now before us, may be thus briefly stated. He arranges the whole group under the two classes of — I. Con- chifera; and, II. Mollusca. The first contains the bivalve shell-fish, and is again divided into two orders : one of these is called Conchiferes dimyaires, the in- terior of the shells presenting two muscular impressions, separated and lateral; while in those of the second order, or Conchiferes monomyaires, there is but one muscular impression, placed nearly in the centre, — the muscle itself being single, and which appears to run through the body of the animal. Each of these great divisions of bivalves contains several others, denominated sections, chiefly differing in the structure of their feet. ORDER I. CONCHIFITRES DIMYAIRES. SECTION I. Mya. Amphidesma. Aspergilium. Anatina. Corbula. Clavagella. Grr~j, TT Pandora. Fistularia. Septaria. oEOT. 11. Conch, tenuipedes. Saxicava. Petricola. Teredina. Lutraria. Venerirupis. Pholas. Mactra. Sanguinolaria. Gastrochaena. Crassatella. Psammobia. Solen. Erycina. Psammottea. Panopzea. Ungulina. Tellina. Glycimeris. Solenimya. Tellinides. * The first volume of the Hist. Nat. des Animaux sans Vertebres bears the date of March, 1815. CHAP. I. SYSTEM OF LAMARCK. 23 Corbis. Cytherea, Trigonia. Lucina. Venus. Castalia. Donax. Venericardia. Unio. Capsa. Cardium. Hyria. Crassina. Cardita. Anodon. Cypricardia, Iridina. SECT. IIL Hiatella. Conch, lamellipedes. Cyclas. Isocardia. Cuculaea. SECT. IV. Conch, ambignt. Cyrena. Area. Diceras. Galathea. Pectunculus. Chama. Cyprina. Nucula. Etheria. ORDER II. CONCH. MONOMYAIRES. SECTION I. SECT. II. SECT. III. Tridacna. Pedum. Branchiopoda CUT. Hippopus. Modiola. Lima. Plagiostoma. Sphzerulites. Radiolites. Mytilis. Pecten. Calceola. Pinna. Plicatula. Birostrites. Crenatula. Spondylus. Discina. Perna. Podopsis. Crania. Malleus. Gryphaea. Orbicula. Avicula. Ostrea. Terebratula. Meleagrina. Vulsella, Placuna. Lingula. Anonica, (20.) To his second great division, Lamarck restricts the title ofMollusca : these he again subdivides into the five following orders : — 1 . The Pteropoda, which forms a part of our Cephalopoda. 2. The Hydrobranchia, which includes the Nudibranchia, Scutibranchia, and Tectibranchia of Cuvier ; together with the genera Ow- chidium, Parmacella, Umax, Testacellus, and Vitrina : these genera he places in his section Pneumobranchia, and makes them the passage to his third order, or the Trachelipodes, in which all the univalve shells are placed. The fourth order is composed of the Cephalopoda, or cuttlefish ; and the fifth contains the Heteropoda. The genera belonging to each of these orders are as follows : — ORDER I. PTEROPODA. Hyalaea. Cleodora. Cymbulia. Clio. Limacina. Pneumodermon. c 4 SHELLS AND SHELL-FISH. PART ORDER II. GASTEROPODES. SECTION I. Glaucus. Eolis. Tritonia. Scyllzea. Tethys. Doris. Phyllidia. Chitonellus. Chiton. Patella. Pleurobranchus. Umbrella. Parmophora. Emarginula. Fissurella. Pileopsis. Calyptraa. Crepidula. Ancylus. Accra. Bulla-a. Bulla. Aplysia. Dolabella. SECT. II. Onchidium. Pacmacella. Limax. Testacella. Vitrina. ORDER III. TRACHELIPODES. SECTION I. Haliotis. Les Phytiphages. Tornatella. Helix. Pyramidella. Carocolla. Vermetus. Anastoma. Scalaria. Helicina. Delphinula. Pupa. Solarium. Clausilia. Rotella. Bulimus. Trochus. Achatlna. Monodonta. Cyclostoma. Turbo. Planorbis. Planaxis. Physa. Phasianella. Lymnaa. Turritella. Melania. Melanopsis. Pirena. SECT..!!. Les Zoophages. Valvata. Cerithium. Paludina. Pleurotoma. Ampullaria. Turbinella. Navicella. Cancellaria. Neritina. Fasciolaria. Natica. Fusus. lanthina. Pyrula. Sigeretus. Struthiolaria. Stomatella. Ranella. Stomatia. Murex. Triton. Rostellaria. Pteroceras. S trombus. Cassidaria. Cassis. Ricinula. Purpura. Monoceros. Concholepas. Harpa. Dolium. Buccinum. Eburna. Terebra. Colurabella. Mitra. Voluta- Margin ella. Volvaria. Ovula. Cypraea. Terebellum. Ancillaria. Oliva. Conus. ORDER IV. CEPH ALOPODES. SECTION I. Testaceous Cephalo- poda. Belemnites. Orthocera. Nodosaria. Hippurites. Conilitcs. Spirula. Spirolina. Lituola. Renulina. Christellaru. Orbiculina. Miliola. Gyrogona. Melania. Rotelia. Lenticulina. Placentula. Discorbis. Siderolites. Polystomella. Vorticialis. CHAP. I. SYSTEM OF CUVIER. 25 Nummulites. Baculites. SECT. III. Nautilus. Ceph. Cepiaria. Ammonites. SECT. II. Octopus. Orbiculites. Ceph. Monothalama. Loligopsis. Ammonoceras. Argonauta. Loligo. Turrilites. Sepia. ; ORDER V. HETEROPODA. Carinaria. Pterotrachia. Phylliroe. (21.) The system of M. Cuvier differs, in many re- spects, from the above. The Mollusca form the second great division into which this admirable anatomist divides the animal kingdom. These he distributes under six principal classes : 1 . Cephalopoda, or cuttlefish ; 2. Pteropoda, or clios ; 3. Gasteropoda, an immense and heterogeneous assemblage, which we shall presently notice in detail ; 4. Acephala, or bivalve Testacea, at the end of which he introduces the tunicated Mollusca (Tunicata Sav.) ; 5. JBranchiopoda, or anomian shells; 6. Cirripedes, or barnacles. The great variety of ani- mals brought together in the third order, Gasteropoda, obliges our author to divide it into others, the names and contents of which are as follows : — 1 . PULMONIA, con- tains the slugs and snails, both terrestrial and fluviatile. 2. NUDIBRANCHIA, includes all the naked marine Tes- tacea without shells, — as Triton, Doris, Thethys, &c. 3. INFEROBRANCHIA, consists but of two genera, Phyl- lidia and Diphyllidia. 4. TECTIBRANCHIA, compre- hends the Bulla family and the Aplysia. 5. HETERO- PODA, embraces the Firoles and the Carinarice. 6. PEC- TINIBRANCHIA : under this order, arranged in sections, are placed the whole of the Trochus and Turbo families, together with the greatest part of the marine univalve Testacea. 7- TUBULIBRANCHJA, is limited to the genera Vermetus, Magilis, and Siliquaria. 8. SCUTIBRANCHIA, contains Haliotis, Fissuretta., and Emarginula : while the 9th and last order, CYCLOBRANCHIA, consists but of Patella and Chiton. To go into further detail will be needless, since the student will at once arrive at a general idea on the contents of these groups, by the indi- cations already given. 26 SHELLS AND SHELL-FISH. PARTI. (22.) In both these latter methods of classifying the Testacea, there is much to approve and much to dissent from. It is clear that neither of these naturalists., how- ever great their merits undoubtedly are in other respects, have paid any attention to the difference between analogy and affinity : nor have they aimed at anything beyond producing a simple scale or line of connection from one group to another. Now, as no such simple series exists in nature, — whose relations of affinity are always double, and generally treble, and whose analogies are interminable, — it follows, as a matter of course, that both have completely failed in laying down a simple graduated scale of the objects before them. Hence, as the groundwork of both systems is founded in error, no apology is necessary for rejecting them, particularly when the object sought for is the discovery of the na- tural arrangement. It is time, however, to leave the systems of others, and to lay before the naturalist some details of that here proposed. CHAP. II. ON THE TESTACEOUS MOLLUSCA IN GENERAL, THE PRIMARY DIVISIONS, AND THEIR ANALOGIES TO THE VERTEBRATA AND ANNULOSA. (23.) THE testaceous mollusks, or shell-fish, with few exceptions *, are all marine, or, at least, aquatic animals, soft and slimy in their nature, and without articulated limbs, so that such as can move about, crawl upon their belly, or swim in the water by means of the fin- shaped lobes of their mantle. Independent of their peculiar anatomical structure, and merely looking to external characters, the most perfect of the testaceous * Some of the parasitic groups, and the land shells, or slugs. CHAP. II. TESTACEOUS MOLLUSKS GENERALLY. 27 tribes are at once known, either by being covered with a hard shell, or, if without this protection, by having white blood, and being destitute of any processes which perform the office of feet. Many, indeed, are fixed to the surface of rocks, and other substances, where they remain during life ; while others bore for themselves internal cavities, or cells, in which they take up their per- manent habitation; while the least organised are parasitic. The similarity of some of the naked Testacea to the^rme- lides, or sea-worms, is so great, that the older naturalists classed them together ; and even to this day we find a whole division mixed up with the annulose Vermes, or true intestinal worms. Let the student, however, bear in mind that the animals of which we are now speaking have neither joints to their bodies or limbs, nor any pro- cesses, by which they can crawl ; and that their blood is white, and not, as in the Annelides, red. Further- more, the testaceous Mollusca never assume the shape of the polypes ; nor do they possess that radiated form and arrangement of filaments, which give such a pecu- liar aspect to the Radiata. By these circumstances, therefore, the observer may discriminate, in ordinary cases, the characteristic marks of even the aberrant or less perfect Testacea ; while he can be in no doubt as to those which constitute the types. The perfection of the class is seen in those animals whose body is pro- tected by a hard calcareous covering, or shell, either in the form of a twisted or convoluted cone, variously modified, or composed of two principal valves or pieces, more or less flattened, and united by a cartila- ginous hinge. These shells are generally ornamented with a variety of colours, and are frequently polished, on their external surface, in the most beautiful and perfect manner, by the animals themselves. The single shells are called Univalves, and such is the periwinkle and snail ; while the double are termed Bivalves, and are exemplified in the oyster and the cockle. As nature, however, proceeds from one to the other of these groups by gradations of structure, we consequently 28 SHELLS AND SHELL-FISH. PART f. find a few bivalves which assume the appearance of univalves j and others which, from the valves being more than two, were called by Linnaeus Multivalve shells. This term the great Swede applied not only to those animals which really belonged to the Testacea, but to the Cirripedes, or barnacles, which have nothing to do with shells, properly so called. The term, there- fore, is altogether objectionable, and will not here be employed. (24.) Such are the leading external distinctions of the class of animals now before us. Their typical characters are three ; two positive, the other negative. The first is that of crawling upon their belly, yet without feet; the second is their being covered with a beautiful calca- reous shell, which is their constant habitation, and which they have the power of enlarging, to suit the progressive growth of their soft bodies ; the third is, that, if deprived of this covering, they have not the least vestige of rings or joints on their bodies : the mouth, indeed, may be circular, and even the branchia, but this is the only analogy they have to the Radiata. In proportion as nature recedes from this typical eminence, the structure of the shell becomes imperfect, until, in the aberrant groups, the animal is either naked, or is but partially protected by such a covering. (25.) The Testacea, considered anatomically, may be described as soft inarticulate animals, almost always breathing by branchia, or lungs, which vary, however, in the most singular diversity of ways both as to form and situation ; this variation, moreover, takes place in groups so closely related to each other in all other re- spects, that it is perfectly clear no natural arrangement can be founded upon the organs of respiration. The least organised, in fact, such as the Planarice, &c., have no branchia whatever ; so that they only possess two of the characters of the class, — namely, a flattened disk or disks, which act as a foot, and a total absence of joints in their body. Their blood is white, and its circulation, observes Cuvier, is always double ; that is, their pul- CHAP. II. TESTACEOUS MOLLUSKS GENERALLY. 29 monary circulation describes a separate and distinct circle. As for their manner of reproduction, it is even more variable and diversified than their mode of re- spiration. In some, as with Gasteropoda, there is a head with tentacula and eyes, either slightly or very fully developed ; while in the Dithyra, or bivalves, all these parts are wanting. Nearly all, however, have a developement of the skin which covers their body, which bears more or less resemblance to a mantle : but even this assumes innumerable shapes; — sometimes it is di- lated in the form of wing-like fins ; in others, as the car- nivorous Gasteropoda, it becomes a syphon by which the animal breathes. In the naked Testacea, the mantle is simply membranaceous, coriaceous, or fleshy. It is, in fact, utterly impossible to give such a general detail of this diversified class, either in respect to external or internal anatomy, as will not be subject to innumerable exceptions at every step. All the modes of mastication and deglutition, as Cuvier says, are found among these animals ; their stomachs are sometimes simple, some- times multiple. They also present examples of all the modes of generation ; and the same learned anatomist confesses that " these varieties of the digestive and ge- nerative processes are found in the same order, and sometimes in the same family." * Hence it inevi- tably follows, that any system founded solely on any one or more of these anatomical considerations, is sure to be not only unnatural, but perfectly unintelligible to the great bulk of naturalists, who are referred to the soft parts of an animal which they never saw, and cannot procure. In regard to . the nervous system, Mr. MacLeay has well observed, that " the most ge^ neral notion we can form, at present, of the nervous system of the Mollusca, is, that the medullary collar, in the more typical groups, must always, in its circum- ference, contain four ganglions, which may either be united two and two, as it is probable they are in the * Griff. Cuv. p. 4. 30 SHELLS AND SHELL- FISH. PART I. Acephala (Dithyra), or all four together, as in Tritonia. The brain is always composed of two of these lobes, which are generally connected, as in Aplysia, or some- times separate, as in Haliotis and Patella : the remaining two ganglions of the collar send off nerves to the or- gans of respiration, &c., and are either united together, as in the common slug and Patella, or are separate, as in Aplysia." It is time, however, to quit these ge- neralities, and enter into more definite details. (26.) A rapid survey of the general peculiarities of the class will not, however, be here misplaced. We have said that these animals have no distinct feet, or any organs which, by forming appendages to their body, supply their want. It is, however, customary — although the appella- tion is certainly incorrect — to call that part of the body which is next to the ground, and which is generally smooth and flattened, the foot, when, in fact, it is merely the belly, assuming only the office of a foot, and the shape of a sucker : by alternately contracting and extending this part, the animal moves forward, — slowly, indeed, but very surely. The aquatic species are able to crawl on marine rocks, even when the sea is greatly agitated ; and every one knows the tenacity with which a slug will adhere to the substance from which we attempt to remove it. This is at once explained by the smooth disc of the belly acting as a sucker, like the tail of the leech. This mode of progression is almost universal among the Gasteropoda, or univalve shell-fish ; but, in the bivalves, the body of the animal is frequently length- ened behind, so as to assume a much more analogous appearance of a foot than what we find in others. The common cockle is one of the best, as it is one of the most familiar, instances of this structure. Those who have watched these animals at the ebb of tide, know that they leap very frequently ; but on their method of doing this two opinions have been given : some main- tain that the foot, which, when protruded, forms a sharp angle, is the chief organ made use of; while Bothers assert that this motion is caused by the sudden CHAP. II. TESTACEOUS MOLLUSK8 GENERALLY. 3l shutting of the shelly valves, which produces a jerk. In some very few instances among the typical Testacea, as in the genus lanthina, or oceanic snail, the animal has a cellular organ attached to the belly, by which it floats on the surface of the ocean, or sinks to the bottom, at its own pleasure. The power of swimming, how- ever, is chiefly found among the aberrant groups, such as the cuttlefish (Cephalopoda), the tritons (Nudi- branchia), and the Tectibranchia : the first of these may really be said to possess fins ; while the naked tri- tons, no doubt, use the appendages of the body for the same purpose. The power of adhesion is also differently bestowed : in the cuttlefish and Planaria, it resides in the innumerable suckers which terminate the arms of one, and are placed on the under side of the other. In the limpet (Patella), the ear-shell (Haliotis), and the chiton, it originates in the excessive breadth of the disk upon the belly, which covers a surface equal to that of the whole animal and its shell : so firmly, indeed, do these genera adhere to the rocks or other substances upon which they are found, that they can only be sepa- rated by great force. It is among the limpets that we find the power of locomotion at its lowest ebb ; for they seldom remove far from the spot on which they were born ; and many, from the shape of the shell corre- sponding to the surface of the rock, appear never to have done this : finally, in the genus Hipponix, we arrive at a positive certainty that the animal is fixed, because it adheres by a separate distinct plate, which thus, in point of fact, renders it a bivalve shell. At- tachment, however, is much more prevalent among the bivalves, where we have entire families fixed to marine substances, either by one of these valves, as the oysters, or by a packet of strong fibrous threads. The attached genera are much less numerous than the others, and are affixed in different ways. Some, like the muscles (My- tilus), are merely connected into little bunches or fa- milies, by slender and scattered threads, strong enough to keep them together ; others, as the Pinnae, or wing- 32 SHELLS AND SHELL-FISH. PART I. shells, are provided with a thick tuft of silky hairs, called a byssus, which issues from one side only of the shell, the other end being firmly attached to marine bodies. In both these families, however, there is still some slight locomotive power left; for, although the animal does not, and probably cannot, quit the spot by disengaging its byssus, and mooring itself to another station, still it is not rendered absolutely motionless : the waves can move the shell backwards and forwards, and the fish may be compared to a horse or other animal fastened by a very short rope, which, neverthe- less, permits him to move his body and limbs. In the Pholas, we have the next step towards an absolute ex- tinction of the power of moving. These shell-fish have no byssus, nor are they affixed by any other method ; yet, soon after birth, they perforate the substance upon which they have been deposited by the parent, and ex- cavate for themselves deep burrows, or caves, exactly of the circumference of their own shells ; and in these hollows they take up their permanent residence. It is not absolutely ascertained, indeed, that these boring Testacea cannot quit their first habitation for another ; but there are many reasons to authorise the supposition that they live and die in the same which they excavated when young, and which they have the power of en- larging as they increase in size. Within such a narrow compass, it is obvious that the Pholas is more a prisoner than the Pinna or the Terebratula, because the walls of its habitation keep it immoveable, so that even the agitation of the waves cannot give it that undulating motion enjoyed by the byssiferous families. Finally, we come to such as are absolutely cemented by one of their valves to rocks or stones,, or to each other : many of the oysters are of this description ; but the most con- spicuous are the different species of Chama and spon- dyles ; several of which have the entire surface of one valve fastened by a calcareous deposition to rocks, pieces of floating timber, and to the bottoms of ships. It is, consequently, in these families, and in the worm-shells, CHAP. II. TESTACEOUS ANIMALS IN GENERAL. that we have the most perfect examples of the sedentary Testacea. (27.) Although the head, where it exists,, of the Tes- tacea, is very different from that of vertebrated and annulose animals, — inasmuch as it is not separated from the body by a neck, — it is yet to be distinguished, in many groups, by the presence of tentacula, or feelers, and by two or four black dots, which are generally con- sidered to be the organs of sight : in proportion as we advance from the Planaria on one side, and from the chitons on the other, towards the cuttlefish, we find the head and the eyes gradually assuming that definite shape and structure which are so characteristic of the vertebrated animals. Some of the tritons (Nudi- branchia), and all the bivalve shell-fish (Dithyra), have no indication of eyes, nor have the latter any obvious head ; but in the Gasteropoda, or univalves, both begin to appear. We see this in the garden snail, and in all the freshwater and marine animals of this tribe. In the Sirombidee and the Volutidce, the eye is nearly as perfect as that of the cuttlefish. From this group, however, nature again recedes ; and in the Pteropoda, although the general form is preserved, the head is once more confounded with the body, and the eyes disap- pear. (28.) On the habits, food, and geographic distribu- tion of the Testacea we can say but little which is applicable to all. The great majority are aquatic and marine ; but two or three extensive families are found only in fresh water. The land shells are exceed- ingly abundant in species, and the gastropod worms are parasitic in or upon other animals. It may be here remarked, that all the bivalves (Dithyra) are aquatic, but that the univalves inhabit the different situations just enumerated. The food of all these creatures varies according to their own particular races. A large num- ber (forming the phytophagous gastropods) feed almost only upon living vegetables, either terrestrial or aquatic, — as the snail of our gardens, and the periwinkle of our D 34 SHELLS AND SHELL-FISH. PART I. coasts ; but a still greater assemblage are carnivorous, — devouring not only living, but dead, animals, and even attacking other tribes of their own class. It would be interesting to know in what manner nature has pro- vided for the sustenance of such as are permanently affixed to one spot. Some of these have divers me- thods of exciting little currents in the water, by which means fresh portions of it are brought to the mouth, along with which such minute animals or fragments of vegetables as are adapted for food are secured. The branchipodous bivalves, like the Terebratulce, although sedentary, are provided with long fringed processes, which are, no doubt, employed to capture their prey, in a similar manner to the arms of the Cirripedes, or barnacles; while the cuttlefish (Cephalopoda) and the Tritonia swim about in search of marine animals weaker than themselves. In regard to their geographic distribution, much might be said, did we not fear being drawn into longer details than our space would permit. It will be only necessary to observe in this place, that the geographic range of the Testacea is not so wide or uncircumscribed as the generality of authors assert. Tropical latitudes, as usual, display a greater variety of species, and a larger number of individuals, than those seas which lie under temperate or frigid skies. The Testacea of Europe are as distinct from those of America, as the latter are from those of Aus- tralia, Africa, or Asia. We have already illustrated this fact in that part of our series devoted to the geo- graphic distribution of animals ; and it may be safely asserted that the grand features of zoological geography are as conspicuous in this class of animals, as in any other. (29.) The great natural divisions of the testaceous Mollusca appear to us to be these : — The first, or pre-eminently typical, are unquestionably the GASTERO- PODA, or spiral univalves, whether we consider the comparative perfection of their internal or their external structure.. The second, or sub-typical class, is com- CHAP. II. PRIMARY DIVISIONS OF TESTACEA. 35 posed of the DITHYRA of Aristotle,, or the bivalves, whose structure is less perfect, but which are in like manner protected by a regularly formed, and often richly coloured, bivalve shell. The third, or aberrant group, as usual, comprehends three : 1 . The NUDIBRAN- CHIA of M. Cuvier, or the naked Gasteropoda; 2. The PA RENCHYM ATA, or intestinal Testacea; and, 3. The CE- PHALOPODA, or cuttlefish. We shall first slightly glance at the leading characters of each of these classes, and then endeavour to trace their analogies to other animals. (30.) Under the name of GASTEROPODA, we retain the greater number of Cuvier's divisions*; but the most typical consists of the univalve or spiral Testacea, whose body is protected and generally coveredt by a calcareous shell : the head, although not assuming a very decided shape, is always present, and is, in almost all instances, at once distinguished by having two or more tentacula, assuming the appearance of the antennae and the palpi of insects. All the true Gasteropoda possess the rudi- ments of eyes ; in the generality, these organs appear in the form of black specks, either at the tips of the longest pair of tentacula, as in the common snail, or at their base. We thus find that the true Gasteropoda possess four primary characters, — the power of crawling upon their belly, the possession of a head and eyes, and, finally, the protection of a shell. Those which are most remote from the point of perfection, and which form the links of connection to other classes (as the Tectibranchia on one side, and the Nudibranchia on the other), have some one, or, perhaps, two, of these characters either lost, or but very imperfectly developed; these, in short, are the aberrant groups, and must never be looked to for the right understanding of the class to which they belong. The slug, for instance, has no shell, or merely the rudiments of one ; yet it crawls upon its belly, it is furnished with a distinct head and even jaws, it has four tentacula, and a pair of rudi- * As the Heteropoda, Cyclobranchia, Scutibranchia, and Pvlmonaria. f Except in Limax, &c. D 2 36 SHELLS AND SHELL-FISH. PART I. mentary eyes ; it presents us, in fact, with all the cha- racters of a testaceous gastropod, except one, — that of being covered by a shell. In the Tectibranchia, again, we have a group still more remote from the typical structure ; for many of these have the mere rudiments of a shell covering a small part of their body, and they swim as much as they crawl. Yet their evident connection to the Volutidae (by means of the Cyprceidce) on one side, and to the chitons on the other, points them out as truly belonging to this order. (31.) The DITHYBA of Aristotle, or bivalve shells, form the next, or sub-typical division. This comprises animals destitute of an apparent head, but still inclosed in a shell, and still moving on the belly. There is not, however, in this latter part, any flattened disk ; and the shell, instead of being spiral, is generally composed of two pieces, or valves, joined together by a horny liga- ment. The Dithyra, moreover, are further distin- guished by having neither tentacula, nor the least vestige of eyes. We meet with some, indeed, as the Chelisomce, which have no external shelly covering ; and others, where the bivalve shell is inclosed in a tube, as the family of Ttibulibranchia, — thus assuming the disguise of a univalve. But these remarkable de- viations are few, and point out, as we have just men- tioned, the extreme limits of the tribe. (32.) The NUDIBRANCHIA, or tritons (part of the naked Gasteropoda of M. Cuvier), form the third of our principal divisions, and are all no less strongly cha- racterised. Destitute of any covering, and presenting a marked peculiarity in their external branchia, their appearance is so very different, that every unprejudiced observer cannot but wonder they should, up to this day, have been mixed up with the true gastropod shell-fish. These animals, in fact, are entirely flattened, naked, soft, and generally ornamented with beautiful colours ; they move about by means of their foot, or concave underside of their belly, in the depths of the ocean ; on the sides, and often on the upper part of their CHAP. II. PRIMARY DIVISIONS OF TESTACEA. 37 bodies, they are provided with processes like filaments ; and there are 'generally two very short tentacula, at the teimination of which are two black dots, representing the eyes ; in this respect they certainly show a relation to the Gasteropoda, but then their respiratory organs are totally different. The Nudibranchia, in short, as their name implies, have these organs arranged on the upper part of their body, in the form of a rosette, so as exactly to resemble a bunch of vine leaves, whose stalks form a common centre. One, out of the three great characters of the typical Testacea, is yet retained, — for the animal crawls upon its belly; but has lost the other two, — since they have neither a distinct head nor shell. The tritons and dories have the additional power of swimming and crawling on the surface of the sea, with their foot uppermost : in the former case, they are pro- pelled both by their branchia and the thin sides of their body, which act in the manner of fins. (33.) Our next group is composed of those simply constructed Testacea, which represent the Acrita in this class, and which have hitherto been arranged among that heterogeneous assemblage of animals, named Intes- tina by Cuvier. Having now arrived at the most re- mote limits of the Testacea, we find, in the order before us, nothing more than faint indications, or, in other words, the elements, of that organisation which belongs to the typical tribes. The flattened disk-like form, indeed, of the dories and the tritons is fully preserved in the Planarite, and even in some of the FasciolcK ; but the branchia, hitherto so variable, now become less and less apparent, and finally disappear. Some of these animals inhabit the water, but others are internal or external parasites ; and this change of habit takes place in groups so intimately connected in all other respects, that we become convinced of the propriety of retaining them in one and the same assemblage. Hence, without venturing to determine the precise limits of the animals which really belong to this class, we feel no hesitation in considering a large portion of Cuvier's PARENCHYJHATA, 38 SHELLS AND SHELL-FISH. PART I. or intestinal worms, as truly belonging to this class. Our reasons for this will be again adverted to. At present, it will be sufficient to state,, that these animals are totally distinct from the true Vermes, where the body is composed of articulations more or less developed, and which consequently form the corresponding group in the annulose circle. Nearly all of these imperfect and obscurely known animals, however, partake of the general character of the Testacea, in crawling or adhering by their belly, beneath which, — as in the Fasciolce, — there are cup-shaped disks, or suckers. Analogous, in every respect, to these, are the arms of the next tribe. (34.) In this manner, then, are we conducted to the fifth and last tribe of the testaceous Mollusca, — namely, the CEPHALOPODA, or cuttlefish. But this is done by the intervention of a group of ani- mals, almost as simple in their organisation as the intestinal tribe last mentioned. Some of the Ptero- poda, in fact, like the Parenchymata, are without head, branchia, eyes, or any external members j even the fin, so universal among the Firolce, is wanting in such genera as Timorenia and Monophora : but these, or any of the Heteropoda, are not the animals to which we must look for the typical characters of the group before us. The types of the Cephalopoda, in fact, are the most highly organised, and, therefore, the most perfect, of all the Testacea. The appearance of these animals is strange and grotesque in the extreme. Their body is soft and pulpy, having the limbs ar- ranged in a circle round the mouth ; these limbs per- form all the offices of feet, arms, and tentacula, and, in many genera, they are used also as fins. The head, which, in all the other Testacea, -is either wanting or but slightly developed, is here large and conspicuous ; while the eyes are so clear and distinct, that they re- semble those of a vertebrated animal ; the mouth, from the arrangement of the limbs, or, as we shall term them, the arms, is consequently in tiie centre, like that CHAP. II. THE CEPHALOPODA. 39 of a radiated animal ; and the sides of the body are either slightly dilated into a distinct fin-shaped mem- brane, or are so thin that it can be used for the same purpose. In size, the cuttlefish are by far the largest of all the testaceous Mollusca ; they are, indeed, the giants of invertebrated animals ; for, if the accounts of the old Indian voyagers are true, there are some of such enormous dimensions, that they seize upon the divers, entangle them in the folds of their serpent-like arms, and finally devour them. These stories are, no doubt, exaggerated ; but we have, ourselves, seen many of such a size, caught on the shores of Sicily, that two would be a good load, — their arms being as thick as those of a man. Most of these animals now in exist- ence are naked ; but in the former seras of the world, there appears, unquestionably, to have been a most numerous and gigantic race, which had a part of their body protected by a spiral shell, rolled in the form of a disk. Ancient revolutions of our globe, however, have swept away nearly the whole of these testaceous monsters, leaving in the Nautilus almost the only genus hitherto found in a recent state. It is among the existing genera that we find a horny or calcareous plate, which supports the body, and is altogether in- ternal. This, as before remarked, is the first indication of the vertebrated structure among molluscous animals ; and hence, nearly all zoologists place these animals immediately in junction with the Fertebrata : or what is the same thing, consider them the last in the series of the Mollusca. It thus appears, on a general view of the whole of the testaceous Mollusca, that they may be thus concisely described : — The typical and sub-typical divisions crawl, and are covered with calcareous shells ; of which the first is univalve, and generally spiral, while that of the other is bivalve and simple. The aberrant group, on the contrary, have no calcareous covering, but are externally naked, and they have the faculty of swimming added to that of crawling. Thus, we cannot but admire the simplicity and beauty of the D 4 40 SHELLS AND SHELL-FISH. PART I. distinctions which nature has thus stamped upon the primary groups,, infinitely diversified as they are in all other respects. (35.) Our next object is, to show upon what grounds our conviction rests, that these orders form a circular group,, more or less perfect. It is hardly necessary to apprise the zoologist, that in this class of animals, above all others,, the effects of those revolutions in our globe, which have nearly exterminated so many races of animals, are most apparent. It appears, at first, difficult to say whether this destruction has been most extensive among those whose hard vestiges yet remain in a fossil state, or among such as, being entirely soft, have alto- gether disappeared, and "left not a wreck behind." Our own opinion, however, is decidedly in favour of the latter supposition. Four fifths of the testaceous Cephalopoda have certainly disappeared ; yet their shelly portions, abounding in incalculable quantities in all the older formations, are yet sufficient, with the aid of the few species now existing, to give us some general idea of the chain of continuity : but, among the Nudibran- chia and the Branchiopoda, whole families seem to have disappeared : such of the latter, indeed, as possessed a hard covering may be judged of by their shells; but in what way their union was effected with the existing races of Dithyra it is altogether impossible to judge. The Nudibranchia, again, are allowed by all naturalists to constitute a distinct tribe ; and yet it does not con- tain more individuals, or a greater diversity of structure, than may be met with in any one of the numerous families of the gastropod Testacea. Now, it must be remembered that these are all soft, and often sub- gelatinous, animals, without any hard or durable parts whatsoever ; so that all that have only existed in former periods of our globe, have been exterminated both in life and substance, no indication whatever remaining that they ever had existence. Upon what ground, then, it may be asked, do we take for granted that they have ever been among the things that were ? and what CHAP. II. ON EXTINCT ANIMALS. 41 reason is there to suppose any one has been abstracted from the living races ? To this we would simply re- ply, that such a conclusion is borne out by every prin- ciple of analogical reasoning. Throughout the whole of the vertebrated classes,, it is solely in groups where congenial forms have been found in a fossil state that we find the gradations in the living series broken and interrupted. Very few such interruptions, for instance, occur in the class of birds, and they are so slight as hardly to merit such a term: this fact, in our esti- mation, at once accounts for the extreme rarity of the remains of birds in a fossil state; scarcely any having been exterminated. The living series is, consequently, almost perfect. Not so, however, among the reptiles. In that class there is an entire order (the Elaniosaures) which has been so absolutely exterminated that not a living example remains ; hence, but for the fossil bones of the Ichthyosaurus, Pksiosaurus, &c., there would not merely be a wide and violent disruption of the reptile series, but an absolute impossibility of forming even a rational conjecture as to its course ; at least, in that dissevered portion which these extinct reptiles actually fill up. But we will bring this theory more home to our present purpose. There is no circular series of living Testacea, wherein is found every modification of form necessary for unquestionable connection, more perfect than that of the predaceous shell-fish (Gasteropoda Zoophaga^): hence the extinct fossil species are not pnly rare, but they nearly all belong to genera now living, and therefore termed recent. Any one family in this group, in short, contains more species and genera than are now known in the entire tribe of Nudibranchia, or in the family of Branchiopoda. What, then, are the legitimate deductions from these facts ? We must take our choice of these two: — Either we are to suppose that Nature at first made these latter groups as imperfect as they now are, while all others, abundant in recent species and forms, are perfect j or that she has removed from the creation most of those links which would fill up the 42 SHELLS AND SHELL-FISH. PART I. intervals between the existing races, and which,, were they now living, would render all her groups equally perfect. All analogy, drawn from theory or from facts, compels us to embrace this latter conclusion. PERFEC- TION in all His works is one of the attributes of the Creator; it is therefore clear that nothing imperfect could have entered into the plan of the creation. (36.) An attentive consideration of the vertebrated classes of animals, both collectively and separately, will convince the philosophic inquirer, that in every instance nature begins, as it were, from a small rudimentary group, — a point, so to speak, in existence, — which seems to contain such animals as have the very least affinity to those which, standing at the head, exhibit the typical structure ; they possess only the rudiments of the perfection to which they gradually, but ulti- mately, lead; and their structure is often so exceed- ingly simple, that, in such as may be termed the germ, even these rudiments are scarcely perceptible. One such, or at most two, are all we can expect to find. Hence it follows, that such imperfectly formed beings, although found in every large division of animals, must neces- sarily possess a strong resemblance to each other ; al- though, in reality, they belong to classes widely distinct, when we trace them up to their full developement. This theory, although in some respects not new, — for it has been tacitly or indirectly admitted in a general way, — has never received that attention it deserves. It has consequently resulted, that nearly all those authors who overlook the important differences between analogy and affinity, have naturally supposed these rudimentary animals, as they may be called, were closely connected to each other by affinity, and have accordingly classed them as such. This seems to be the true cause why we have such a heterogeneous assemblage of animals under Cuvier's class of Intestina, and even in those of Mac- Leay's Acrita and Vermes. They agree, indeed, in one respect, — that is, of being the most simple of all others in structure; but this is altogether more a negative CHAP. II. ON RUDIMENTARY TYPES. 45 than a positive character, and altogether fails of that accuracy, to be desired. Besides, it is quite evident, that, if the several threads of affinity — collected together in the above-mentioned groups — had been followed up, each would have been found leading to totally dif- ferent divisions of the animal kingdom. The Acrita, in fact, as at present constructed, is such an ill-defined group, that some writers think they are bound to bring within its limits the Medusas, and many of the most perfect radiated animals ; so that, if this is allowable, there is no reason whatever for excluding the annulose Vermes, the cephalopodous Foraminata, and the mol- luscous Parenchymata. It may be thought somewhat premature to state these objections, seeing that we have not yet attempted to substitute any other arrangement of the Acrita * for that which we hold to be a false one, although proposed by the very founder of the class. But we are all aware that the perception of an error, and the power of rectifying it, are not inseparable. Our researches may have proceeded quite far enough to satisfy us on the former, and yet may not have extended, or have been sufficiently matured, to accomplish the latter. It is precisely in this predicament that we now stand. Our researches in the true Acrita, the Radiata, and the Annulosa, — have advanced sufficiently far to convince us of the fundamental truth of what we have just advanced. The subject, however, is of such vast importance to the first principles of natural arrange- ment, that we may well devote to it a few additional remarks. (37.) If we look to the vertebrated circle of animals, we find that many of the amphibians are the most simply constructed of all the Vertebrata ; the Amphiuma are worm-like salamanders, having the body excessively * We trust this investigation may be taken up by the only naturalist of this country who has devoted himself to the study of the sort Molluscat and from whose talents, experience, and zeal, we may expect so much — Dr. Johnson. It is a serious loss and inconvenience to science, that the numerous and truly valuable memoirs of this accomplished malacologist are now scattered in periodicals and magazines, almost hid in a mass of temporary and trivial articles. 44 SHELLS AND SHELL-FISH. PART I. lengthened, and the legs and feet so small as to be rudi- mentary ; while the Coscilia have neither feet nor bran- chia, and sometimes are without eyes. This group, therefore, among the Fertebrata, is precisely the sort of point or nucleus from which diverge two distinct series of animals : the one leads to the serpents, or reptiles ; the other branches out, in an opposite direction, to the fishes ; but both these ultimately meet in the ostrich, which exhibits a union of the bird and the quadruped. Each of the five divisions of the vertebrated circle afford parallel instances ; so that we invariably find the most aberrant group is always that which is the least or- ganised ; just as is the class Acrita in the whole animal kingdom. The annulose Vermes, as the tape-worms, and other intestinal creatures still more simple, forming the Tanioides of Cuvier, are, in the annulose circle, precisely what the amphibians become in the Vertebrata. They exhibit the first simple outlines of that structure which terminates in the painted butterfly and the sa- gacious bee ; and, when nature has reached these points of perfection, she returns, by slow degrees, through the Annelides, or red-blooded worms, to the same point, although by a different route. Such, also, will be found her course in the testaceous class. The Paren- chymata, or parasitic Mollusca, may be considered the first indistinct and incipient developement of the Tes- tacea, — the point from which nature diverges towards the phytophagous gastropods on one side, and to the car- nivorous gastropods on the other, until both these series meet together, and form a perfect circle in the family of TurbidcB. It will subsequently appear that this re- markable principle of variation is not merely confined to the first great circle formed by the Testacea ; it is abundantly evident in its primary divisions — nay, in some instances, even in its families. Among the Ce- phalopoda it is particularly strong. All writers who have mentioned the Foramimfera, so admirably and beautifully investigated by D'Orbigny, hesitate not to place these microscopic atoms in that order, although it CHAP. II. ON THE TYPES OF ACRITA. 45 contains the most perfect Mollusca in existence. And yet the organisation of these beings is so very simple, that, if no regard be paid to the difference of analogy and affinity, they might be placed next to the animalculae in the class Acrita. The chitons among our Gasteropoda, and the genus Chelisoma in the circle of the Dithyra, are further instances : both are the most simple and slightly organised of their separate groups ; and both, in this respect, as well as in the shape of their bodies, are prototypes of the Planaridte and Fasciolce, among the parasitic Testacea. But the universally confessed affinities of the naked slugs to the testaceous snails brings this theory home to the personal cognisance of every naturalist. Some of these creatures are so small, ge- latinous, and so little organised, that, but for their in- disputable and immediate affinity with the beautiful land shells of the Helix race, no one would think of placing them in the same order, much less in the same family ; and yet every zoologist sees that such is their natural situation. Hence these naked slugs become nothing more than prototypes of the Planarice and FasciolcB ; related, indeed, to them by analogy, but without any connection whatever in regard to affinity. The extraordinary genus Herpa, one of the splendid discoveries of Guilding (which will be subsequently noticed), carries this analogical resemblance to the highest pitch ; so that, but for the discriminating acumen of that profound observer, we should have been tempted, without seeing the animal, to consider it was an actual type of Planaria, in the disguise, only, of a Limax. On these, and numerous other similar facts resulting from the analysis of this class, we hesitate not to place a por- tion of Cuvier's intestinal worms as the most aberrant order of the testaceous Mollusca. We wish to follow nature, and nature only ; perfectly satisfied, from past experience, that, however various and conflicting may be the comments of her interpreters, she has pursued but one course, and but one plan, in her system of animal variation. 40 SHELLS AND SHELL-FJSH. PART I. (38.) We may now commence a rapid survey of the course by which the class before us resolves itself into one great circle, the further details of which will be noticed under the several chapters devoted to the chief divisions. We have already expressed our con- viction that the germs of the Testacea exist among the various discordant animals comprising Cuvier's Paren- chymata, but it is by no means clear which is the pre- cise point where the very first indication of this struc- ture is seen ; this cannot be cleared up until the Acrita and the Radiata, not to mention the annulose Fermes, have been sufficiently analysed. Without speculating, therefore, on the probability or possibility of such genera as Echinorynchus and Herula being the rudi- mentary type, we may safely point to the Tremadotes of Rudolphi, and the whole of the second family of Cuvier's Parenchymata, as containing the vermiform or most aberrant types of the class before us. These, in fact, are nothing more, in one sense, than naked gas- teropod Mottusca, crawling upon their bellies, or ad- hering by means of cup-shaped suckers, which are analogous to, and perform the same office as, the single disk of the more perfect testaceous gastropods. Some of these, like the Fasciolce of Linnaeus, are feeders on the internal parts of animals, and adhere, by means of these suckers, to the viscera of quadrupeds, birds, and fish ; others, as Cyclocotyles of Otto, are external para- sites ; while the true Planaridcs are entirely free, and swim about in the water. Now, it is from these animals that nature throws out, as it were, two lateral branches. One of these, emanating from the Planarid-ee, conducts us, in the most beautiful and graduated man- ner, to the Nudibranchia ; the other, departing from the FasclolfB, leads us, by means of such genera as Menostoma of Blainville, and Hectocotyles of Cuvier, to the no less vermiform animals among the Firolce and other finless Heteropoda. This latter branch, however, we shall leave after this indication, and pursue the for- mer. Commencing, then, with the Planarlda, we see a CHAP. II. GREAT CIRCLE OF THE TESTACEA. 47 family as much diversified as any of the naked Testacea, but which, at present, remains almost as a genus. In it are found representations of nearly all the onisciform Mollusca, as Sigaretus, Chelisoma, Chelinotus, Chiton, and numerous others : the interesting genus Tristoma of Cuvier, contains the first rudiments of branchia, — for such do we consider that " ramified circular vessel in the parenchyma of the body/' the nature of which, as that learned anatomist conceives, " it is difficult to determine." * This, together with the many beautiful and interesting forms discovered and figured by Rup- pell, establishes the union of the Planaridce and the Dor idee — in other words, the two orders of Parenchy- mata and Nudibranchia — in the most perfect manner. We pass, then, from these latter, to the Branchiopoda, the first tribe in the order of bivalves. From this point our course is plain : Anomia connects them with the Ostrcea and other Dithyra without siphons ; while these latter are connected to the more typical bivalves, where these organs are fully developed, by means of Chama and Hippopus. We quit the perfect bivalves for such as are tubular, and hence almost univalve shells, through the MyadcB and Solenidce, and thus reach the Teredines. By this latter family, the path is smoothed to the terminal series of the Dithyra, — namely, the Tubuli- branchia of Cuvier, — where we have the singular union of a gastropod mollusk inhabiting a tubular shell. The two typical orders being thus united, we enter, at once, among the spiral or testaceous Gasteropoda, — that group, in short, which stands at the head of the entire class. Beginning with the Scutibranchia or Patellides, as the least organised of these univalve animals, we see a gradual developementof the spire take place in theHalio- tidce, Trochidce, and Helicidce ; until, in the Turbidce, we have a union of the phytophagous and the zoophagous gastropods. The old genera of Melania in one, and Cerithium in the other, effects this union, and conducts us at once to the Strombidce, Muricidce, and, finally, to * Griff. Cuv. xii. 473. 48 SHELLS AND SHELL-FISH. PART I. the Volutidcs. The transition from these to the Cyprceidce is no less clear than that from the Cypraida to the Bullce, ' — the latter being the most perfect of the Tectibranchia. In some of these half naked gastropods, the foot-like disk of the belly is reduced to very small dimensions, while the two lobes of the mantle become so dilated that they are used as fins. In this manner does nature leave the GASTEROPODA, and unites them to the swim- ming order of CEPHALOPODA,, — the first tribe of which is the Pteropoda. The straight cylindrical case of some of these singular animals,, few in number, but highly in- teresting, prepares us for that extinct tribe of cuttle- fish of which the fossil Belemnites, in all probability, formed the type : from these to the spiral Cephalopoda, the passage is so easy, that it can be traced by the shells alone ; and then, with the assistance of Argonauta and Carinaria, we at once reach the Heteropoda. The affinity between some of these simply constructed animals and the aberrant Parenchymata has already been intimated. Thus we find that the two lateral series which branch off from the Planarldce meet toge- ther in the Turbidte, and complete the circle of the whole class. (39.) In thus tracing the course of the circle of the TEST ACE A, the zoologist, versed in the circular theory, will perceive we have taken no notice of the most aber- rant groups in each order, — and this, because it would have incumbered, without necessity, the simple ex- position of the union of the orders themselves. He will also be aware that it is by these particular groups that each order forms a circle of itself. This important pro- perty will, of course, be adverted to when we come to treat of each order separately. In the mean time, we shall now compare the orders of the Testacea with such other groups of the animal kingdom as appear calculated to render their analogies more comprehensible to the ordinary reader. Our first comparison will consequently be with the vertebrated animals. CHAP. II. ANALOGIES OP THE TESTACEA. 49 Analogies of the TESTACEA to the VERTEBRATA. Orders of the Testacea. Circle of the Vertebrata. GASTEROPODA. QUADRUPEDS. DITHVR*. BIRDS. NUDIBRANCHIA. REPTILES. PARENCHYMATA. AMPHIBIANS. CEPHALOPODA. FISHES. (40.) The reader will bear in mind that, hitherto, we have spoken of relations of affinity ; but our present business is with analogies, or mutual representations. Setting aside, therefore, all we have already advanced, we accordingly find that the best modern zoologists place the Dithyra, or bivalve shell-fish, close to the Gaste- ropoda, or univalves, upon the same principle as the birds, in the other column, follow the quadrupeds. This arrangement, at the very first, seems to carry with it an appearance of being natural, because we thus find that both the Dithyra and the Aves are the sub-typical divisions of their own circles. But this parallelism, although highly satisfactory, is not of itself sufficient ; we must look further, and inquire whether these groups actually agree in any particular circumstance of struc- ture, common to both. Now. every one knows that, among the many things in which quadrupeds differ from birds, their mode of feeding is altogether dissi- milar. Quadrupeds are provided with jaws bearing teeth, with which the food is masticated before it enters the stomach: birds, on the contrary, have the jaws dilated into a snout-shaped bill, and teeth are alto- gether wanting. The rapacious birds (Raptores), in- deed, which typify the quadrupeds, may be said, in some degree, to masticate their food ; but by all others it is sucked into the mouth, the effects of mastication being supplied by the stomach. If we inquire into the modes in which the typical Gasteropoda and the Dithyra take their food, we find that it is precisely conformable to the above variation. The most typical of the spiral shell- fish (Gasteropoda), like quadrupeds, are provided with fleshy lips and corneous jaws, varied, as M. Cuvier truly observes, into numerous modifications ; while in many genera (on the same authority), the inside of the cheeks 50 SHELLS AND SHELL-FISH. PART J. are provided with reflected teeth,, to aid deglutition. On turning to the Dithyra, however, we find a totally different structure : the mouth has neither lips, jaws, nor teeth, hut is " a simple aperture" entering into the stomach ; the food, in short, is sucked in, and is swallowed entire, as it is hy birds : so that, strange as it may appear, the two most perfect groups of the testaceous Mollusca exhibit, generally speaking, the same mode of feeding as the two most perfect groups of vertebrated animals. It seems hardly necessary to strengthen analogies so beautiful ; yet we cannot omit, in this place, that there are not wanting indications, even in the structure of the bivalve shell-fish, to remind us of the peculiar, character of birds : in these latter, the sides of the body are enveloped by two broad and expansive wings ; in like manner is the body of an acephalous bivalve enveloped on its sides by the ample folds of its cloak or mantle. Yet neither of these appendages occur among the typical quadrupeds and the typical gastro- pods.* But it is time to pass on to the Nudibranchia and the reptiles. Do these represent each other ? and in what manner ? We will set aside that forbidding appearance which these reptile-looking Mollusca possess; and which indicates, at first sight, some analogy to the true reptiles, because this is a mere matter of opinion : not so, however, is the circumstance that both these classes crawl upon their belly, and are destitute of any limbs. The tritons, in fact, have no real feet ; and the serpents, standing at the head of the Reptilia, are eminently distinguished in the very same way. The analogies of the Parenchymata, in general, have been sufficiently explained ; it is, therefore, only necessary to observe in this place, that the Amphibia are the most imperfect of the vertebrated animals, just as the Paren- chymata are the most simply constructed, and the fur- thest removed from the typical Testacea. Their short, thick, and broad form reminds us again of the onisci- form type of annulose animals. We have now only to * Except in such as are aberrant in their own circles, as the VolulidCIRRIPEDA. I CHAP. III. THE ORDER GASTEROPODA. 53 So singularly do the Aptera represent the Dithyra by the head (as in spiders and scorpions) being con- founded with the trunk, that they might even, without any violation of propriety, be termed acephalous in- sects. But we presume enough has now been said on this set of analogies, to satisfy the unprejudiced reader. And having now sufficiently dwelt upon our arrange- ment of the Testacea as a class, we may at once pro- ceed to the details of the tribes in which the whole are here arranged. CHAP. III. ON THE ORDER OF GASTEROPODA, ITS PRIMARY DIVISIONS, AND THE CHARACTERS AND ANALOGIES OF THE MURICID-dE AND THE TURBINELLID^E. (43.) THE gastropod shell-fish, as we have already shown in the preceding pages, stand at the head of the testaceous Mollusca, — a station which both Cuvier and Lamarck have also assigned to them. This has now been confirmed by the theoretical and analogical tests with which our last chapter was concluded. But as our ar- rangement of these animals will be in many respects very different from that of preceding writers, it will be proper, before submitting its details to the reader, that we should take a short review of the group as it at pre- sent stands in existing systems. (44.) On referring to the definitions given in the Regne Animal of the order Gasteropoda*, and to the animals composing it, we find it embraces more than nine tenths of the whole of the Mollusca inhabiting univalve shells, and by far the greater part of such as are naked. The inevitable consequence of thus includ- ing a multitude of groups, differing from each other in * Griffith's Cuvier, xii. 21. E 3 54? SHELLS AND SHELL-FISH. PART I. almost every thing, has been this, — that the reader is at a loss to know by what other principle they are united, even according to the system of the learned au- thor. Some crawl on their belly, others do not ; some have shells, others none ; many have a distinct head, but many have not ; the eyes are present, or they are wanting : all the organs, in short, of respiration, deglu- tition, and reproduction, are admitted to vary ; and this, in such an extraordinary manner, and in species so ob- viously allied to each other, that they have no claim to a primary consideration. True it is, that 'all these ani- mals possess an aortic heart ; but this, properly speak- ing, is more the universal character of the testaceous Mottusca as a class, than one by which such an immense number of animals, totally different in all other respects, can be distinguished. The order, as it now stands, may be said to embrace the whole of the Mollusca, except the Dithyra, or bivalves, and the Cephalopoda, or cuttlefish. " There is, no doubt, some great error," observes Mr. MacLeay, " yet undetected in the principles upon which we are accustomed to arrange the Mottusca, and that we shall neyer arrive at the truth, by looking, like M. de Blainville, solely to the position and structure of the organs of respiration ; or, like M. Cuvier, to the method of reproduction, as when he unites the Cyclobranches to the Acephala or Dithyra. (45.) Rejecting, therefore, all those animals from the true gastropods, which have neither a distinct head, as the Tubulibranchia, or whose branchia are naked, as in Doris, we shall retain an assemblage of mollusks, nearly all of which are furnished with univalve shells *; and whose head, distinguished from their body, is provided with tentacula and eyes ; the flattened part of the belly serving them as a foot. Thus restricted, we shall find that nearly all the remaining divisions of M. Cuvier, under certain modifications, indicate so many natural groups. It is clear, however, that when M. Cuvier * Except in Chiton, where the valves are separate and dorsal only, and some of the Tectibranchia. CHAP. -III. TRIBES OF THE GASTEROPODA. 55 places such genera as Planorbis and Ampullaria in two different orders, merely on account of a difference in their organs of respiration, he falls into as great an error as that he has elsewhere committed in uniting the Cyclo- branchia to his Acephala. The order Pulmonaria, there- fore, must be clearly abolished. This, indeed, has been already done by Lamarck, whose authority on all ques- tions of natural affinity must, in general, be regarded as superior to that of Cuvier. (46.) With the foregoing restrictions, the primary divisions of the order before us will be found to consist of the five following tribes: — 1. The ZOOPHAGA of Lamarck, or the carnivorous shell-fish (corresponding to the Pectinibranchia Cuv.); 2. The PHYTOPHAGA of the same author, which live chiefly on vegetables, as the snails and slugs; 3. The SCUTIBRANCHIA Cuv., or lim- pets ; 4f. The CYCLOBRANCHIA Cuv., or chitons ; and, 5. The TECTIBRANCHIA Cuv., or bullas, whose univalve shells, where they exist, are all hid in the flesh of the animal, while their mantle is dilated into two fin-like lobes, with which they can swim. We shall now state a few general particulars of these tribes, and then proceed to determine their analogies. (47.) The ZOOPHAGA are the most pre-eminently typical of the whole of the testaceous Mollmca ; and this holds good, whether we regard the organisation of the animal, or the symmetry and beauty of their ex- ternal shell, with which, in every instance, they are provided. They have only two tentacula ; and the eyes, which are always conspicuous, are sometimes (as in the Strombidce) highly developed. The edge of the mantle is almost always provided with a siphon, or tube for respiration, and by which the animal can breathe without protruding its head and foot from the aperture of its shell : this siphon is protected by a corresponding canal, either long or short, at the base of its habitation ; and its presence, in all these Mollusca, constitutes one of their most essential characters. The mouth, also, is very re- markable, — resembling more or Less, as Cuvier well E 4 56 SHELLS AND SHELL-FISH. PARTI. observes, "an elongated proboscis. Their tongue/' he continues, " is armed with little hooks, which, by slow and repeated rubbings, act upon the hardest bodies." It is by this process that they perforate, with the smoothness and precision of an auger, the shells of other animals, which they then destroy and suck the juices of. The sexes are always separate; and the aperture of the shell, in most instances, is closed by an operculum. The various modern genera formed out of the Linnsean Murex, JBuccinum, Conus, Valuta, &c., are included in this tribe, the shells of which are always spiral, and furnished with a notch or emargin- ation at the base. (48.) The PHYTOPHAGA, as the name implies, are feeders upon plants; for although several, like the slugs, will devour animal substances, they more habitu- ally live upon vegetables. They are, besides, eminently distinguished from the carnivorous race by two cha- racters : their mouth does not form a proboscis ; and the aperture of their shell is entire, — in other words, without the notch or canal for the passage of the siphon (when it exists), so universal in the last group. In all but one or two genera, as the slugs and the marine Onchidce, they are more or less covered with shells, which, in however small a degree, are always spiral. By far the greater part of them have the sexes separate ; but in regard to all the other organs connected with respiration, they may be said to vary in every possible way, — a clear proof that such variations, in groups naturally and closely allied, cannot be taken in an arbitrary sense. Many of these animals have their branchia as in the Zoophaga; some few, as Cyclostoma and Helicina, even according to M. Cuvier's admission (who places them, nevertheless, with his Pectinibranchia), " have instead of gills, a vascular network covering the top of a cavity that is otherwise similar ; and they respire, like the Limax, the natural air." The whole of the terrestrial slugs and snails, again, breathe through an open perfo- ration under the edge of the reflected mantle, which CHAP. III. TRIBES OF THE GASTEROPODA. 57 they can dilate or contract at pleasure : hence they have no gills, " but merely a network of pulmonary vessels, which spread over the parietes and the roof of their respiratory cavity." The tentacula, in such as inhabit fresh water, are generally only two ; but in the land and amphibious groups, as Helix, Amputtaria, Pla- norbis, &c., they are four. Their food, notwithstand- ing all these variations, is always essentially vegetable. Their mouth is uniformly the same, and their shell is always spiral; this latter circumstance, it should be remembered, carries with it an important character in the form of their body, which is of much consequence, and separates them from the next tribe. The whole of the land shells, as well as the marine families of Neritince, Turbida, Trochidte, &c., are comprised in this division ; the HaliotidcB, or ear-shells, being the connecting link to the next. (49.) The SCUTIBE ANCHIA have the same system of respiration, according to Cuvier, as his Pectinibranchia ; but they differ not only in their mode of reproduction, but most remarkably in the form of their body. They are all attached to their shelly covering by an amazing strong muscle, which fills the centre, and gives them such an adhesive power, that they affix themselves im- moveably to other substances, from which they can only be separated by the sudden insertion of some sharp instrument. They are, in fact, affixed Testacea ; for although the animals can move about, they cannot live but upon a substance where they can instantaneously fix themselves. In their internal structure, we find the heart, according to Cuvier, " traversed by the rectum, and receiving the blood from two auricles, as is the case in the greater number of bivalves." * The form of the shell is no less peculiar j its general shape is that of a low, broad-based pyramid, or, if viewed inside, of a very wide but shallow funnel. The common limpet, in short, appears to us the most typical of the whole ; * It is by this group, in fact, as will subsequently be shown, that we consider the Gasteropoda and the Dithyra are united. 58 SHELLS AND SHELL-FISH. PART 1. for although this genus has been excluded by some writers, and separated from Fissurella, &c., in a dis- tinct tribe, yet this is evidently doing a violation to nature. None of the genera in our present group pos- sess spiral shells ; for although Haliotis is obviously intermediate between the Phytophaga and the Scuti- branchia, its preponderating character, both as regards the animal and the shell, appears to us in favour of its being placed as the last of the turbinated families, rather than as the first of the present group. Thus restricted, the Scutibranchia will contain Patella, Siphonaria, Fissurella, Emarginula, Parmophorus, Capulis, &c., together with the singular genus Hipponyx, of which we shall have occasion to speak hereafter. Magilis and Siliquaria evidently disturb this series, yet open a direct path to the Dithyra, or bivalves. (50.) The CYCLOBRANCHIA, according to Cuvier, "have the branchia resembling small lamellae, or little pyra- mids, forming a cordon more or less complete under the borders of the mantle, very nearly the same as the In- fer obranchia," from which, however, he separates them on account of their different system of reproduction : c ' the heart," he continues, GASTEROPODA. C bular siphons. j PHYTOPHAGA. Siphons entirely wanting. DITHYRA.* r Animal oval, greatly depressed;" r Shell, when present, protecting} C nke lobes. " J C the back. CYCLOBRAKCHXA. » ' ' PARENCHYMATA. TKCHBR^CHIA. It is not a little extraordinary that these two series of animals, which in their external aspect are so very dis- similar, should yet present such strong analogies to each other ; the Scutibranchia, in fact, may be called Nudi- branchia provided with shells ; and, in the same way, * The sub-typical group, of course, is the one here compared, and there the animals have no siphon. CHAP. III. THE CARNIVOROUS TRIBE. 6l the PlanaridcB among the Parenchymata are naked chitons (Cyclobranchia). The Cephalopoda, in like manner, are as perfectly represented by the swimming tribe of the Tectibranchia ; and like them, also, have their shell internal. Adverting, again, to the two first analogies, we find the primary types, the Zoophaga and the Dithyra, furnished with long siphons, or tubes, which are totally wanting in the secondary types. To this table, however, we may hereafter return ; and, in the mean time, we shall enter at once on the most typical families of the entire class. (53.) The tribe of the ZOOPHAGA, or rapacious shell- fish, is distinguished by a tubular or proboscis-like mouth, a respiratory siphon, and two tentacula, upon the sides or near the base of which are the eyes. In some few, as in the cowries (Cyprtsa)., the mantle is ex- ternal, and almost envelopes the shell ; and this, we sus- pect, is likewise the case in some of the Volutidce, or volutes ; but in general it is internal, and of ordinary dimensions. Nearly all are provided with a horny oper- culum for closing the aperture of their shell ; but in the Cones and Columbellince this is reduced to a mere vestige ; while in the Cyprceidce, and such as have the lobes of the mantle very much developed, it is unneces- sary, and therefore does not exist. All these variations, however, in the operculum are slight and trivial, in com- parison to those exhibited in the form of the animal and the construction of the shell. Here the greatest variety, and the most regular constancy in the variation of natural groups, is everywhere discernible. Hence it is, that while our primary attention must be directed to the variation of the animal, we must still have a suf- ficient regard to its testaceous covering. It is the abuse, arid not the judicious use, of a regard to the shell, which is to be condemned. A system built only on the vari- ation of the animal, would be as useless and insufficient for all practical or philosophic purposes, as another would be detrimental to sound principles of classifi- cation, if it was framed entirely on the form of the 62 SHELLS AND SHELL-FISH. PART I. shell. The first would include, like the old systems, all manner of spiral shells, under the generic name of Buccinum ; while the other would place Parmophorus, Fissurella, and Umbrella in the same group as the limpet, merely because they had similar shaped shells. While, therefore, we make this and all our other chief divisions to repose on a primary consideration of the soft parts of the body, we regard the construction of the shell as much a part and parcel of the animal itself, as are the wings of an insect or the hard covering of the chelonian reptiles. The shell of testaceous animals, in fact, is precisely analogous to the covering of the tortoises, and are to be considered in the same light, — that is, furnishing a secondary, although a very im- portant, set of characters for the determination of the minor groups. It is not a little remarkable that, as the tribe before us is the most completely organised, and therefore the most typical of the whole of the Testacea, so do we find their testaceous coverings are the most complicated, and by far the most beautiful of all the spiral' univalves. The gradual transitions of form whicji they present, even when there is little or no variation in the animal, or, at least, none that has yet been detected, is a clear proof, if any other was wanting, that all our secondary characters taken from the shell, are those which nature herself has employed to designate the sub- ordinate groups. The definitions, therefore, of the families in which we shall now arrange this tribe, will be mainly taken from the shell, at the same time intro- ducing all such information regarding the soft parts of the inhabitant as appear of primary consequence. (54.) The five leading divisions of the Zoophaga may be thus named and defined : — 1 . The MURICID.E, or murexes, having the respiratory siphon in general very much developed, and its corresponding canal at the base of the shell always straight. 2. The TURBINELLID^E, or turnip -shells, where the base of the shell is straight and lengthened, and the pillar strongly plaited. In both these, the mantle of the animal is never dilated, but is CHAP. III. FAMILIES OF THE ZOOPHAGA. 63 of ordinary dimensions, and drawn back into the shell with the animal. 3. The VOLUTID.E, or volutes, having the mantle much developed in the typical species : the column of Ahe shell is always marked by regular and well-defined plaits, nearly the same as in the last; but the base of the aperture is obtuse, truncate, and notched. 4. The CYPR^EID^E, or cowries, whose shells are without any spire ; the last whorl enveloping all the others, as in the bullas. 5. The STROMBID^:, or wing-shells ; the only division where the outer side or lip of the aperture is considerably dilated. The two first of these are the typical and sub-typical groups ; the three latter form- ing the aberrant circle. The whole are marine. (55.) The MURICID^E, or whelks, are resolvable again into the following sub-families, each of which contains genera and sub-genera : 1 . The MuricincK, or murexes * ; 2. The Cassince, or helmets ; 3. The Buccinince, or whelks ; 4. The Purpurince, or purpuras ; and, 5. The Nassincs. These we shall now enter upon in the above order of arrangement. (56.) The MURICIN.S; is a very diversified and (from the little yet known of the animals) a very difficult group to arrange. Generally speaking, they are strong shells, of a rough exterior, without any plaits or teeth either upon the pillar or outer lip : the different periods of their growth, or rather of their enlargement by the animal, are marked by thickened transverse ribs called varices, which are differently disposed in the genera : the canal is generally short, or of moderate length, but always present, and usually a little bent on one side. The aper- ture is oval; and the spire nearly as long as the body- whorl. They chiefly abound in the shallow waters of temperate seas ; and are either covered with an epidermis of their own, or by extraneous marine substances. The typical genus is Murex, where we find some of the most beau- tifully coloured shells, and certainly the most elaborate in structure, among the whole of the spiral univalves. * Sometimes called rock-shells, from the roughness and irregularity of their surface. 64 SHELLS AND SHELL-FISH. PART I. This and Ranella appear to be the two typical genera ; but of the three aberrant divisions,, Triton is the only one that has been yet named or defined. The foliated varices of Ranella, and the sharp tubercles on the whole shell,, joined to the additional canal at the upper part of the aperture, indicate that this group is naturally con- nected to Murex; but the species are very few, and present no very marked deviation from the typical form. In Triton, however, the case is far otherwise. The species are riot only more numerous, but exhibit in their structure so many different modifications, that there is no one generic character to which there are not exceptions in some of the species. The most usual is that of having but few varices, and these placed alternately ; whereas in Ranella they are so united as to form a continuous ridge on each side the shell, when it is placed with the aperture downwards. But this character is by no means constant. The animal {Jig. 1.) is here represented from an unpublished drawing by Guilding ; the tentacula are short, and the eyes at their base. This remarkable diversity in the genus Triton is easily accounted for, on the ground that this group contains representations of all others in the family, besides aberrant forms leading to the more proximate genera. The two other aber- rant types, which we consider as completing the circle of the Muricince, we name Vitulina and Muricidea. The first is advancing towards Murex, and is repre- sented by the Murex Vitulinus of authors, and is dis- tinguished by having the varices nearly obsolete, and the pillar smooth, broad, and flattened, like a purpu^a. CHAP. III. THE CASSIN^E, OB HELMETS. 65 The type of Muricidea, is the harp-like Murex Magel- lanicus.* Where, as in very many other of the small murexes, the progressive growth of the shell is marked by longitudinal ridges, either foliated or spined, some- times as close together, and nearly as regular, as those upon the harp-shells. The outer lip is quite smooth, and the inner lip thin : there is no internal groove; and the basal canal is almost always closed over, so as to form an internal tube, open only at the two ends. The connection of this group of Murices to the true genus Murex is so close, that they have never, until now, been separated ; so that, being connected to Triton by means of Vitulina, also a Lamarckian murex, we find the whole forming a circular group of themselves. (57.) In the GASSING, or helmet-shells, the first cha- racter which strikes us is their large and often gigantic size : the spire is remarkably short; and the base, instead of being prolonged, as in the Muricince, is either truncated so as merely to present a wide notch, or is very short, and turned back on the body-whorl. These are the typical characters of the sub- family, but much remains to designate the genera. Our attention has been more especially called to this group, not merely from the size and beauty of the shells, but from the great reluctance some conchologists have manifested to adopt the genus CyprcecassiSj proposed by Mr. Stuchbury, whose valuable Essay upon the growth of corals has rendered his name familiar to naturalists. That Cyprcecassis pos- sessed a decided relation, either by affinity or analogy, to Cyprcea, we had long been persuaded. But we freely confess, that previous to, and even for some time after, its being proposed as a genus, we looked upon it only as a subordinate type of Cassis. Anxious, never- theless, to arrive at some definite conclusion on this point, we were induced to re-examine the whole of the Lamarckian genus Cassis; the result of which has con- vinced us that our first impression was erroneous, and that Cyprcecassis is as truly a natural genus as any in * Ency. Method, pi. 414. fig. 4. a, b. 66 SHELLS AND SHELL-FISH. PART I. the whole circle of the Testacea. It will be needless in this place to enter into the definitions of this and the other four genera, since they will be found in our sys- tematic arrangement; but they may shortly be cha- racterised in the following manner : — In Cassidea and Dolium, the aperture of the shell is always wide, rarely with distinct varices, and the outer lip never dilated into a marginal rim over the body- whorl; but in the first, the inner lip is reflected, thickly marginated, and generally toothed, while in the last it is always thin : these will be found, upon analysis, to be the two typical genera. In the harps (Harpa), which obviously follow the tuns (Dolium}, the whole shell is marked by varices, which assume the form of ribs. Now, the ample information given by M. Quoy on the animal of this genus, not only fixes its station in the present circle, but demon- strates it to be a representation of the volutes, with which that admirable malacologist compares it. This im- portant point being determined upon such high authority and unpremeditated testimony, we arrive, by induction, at the station of the two remaining types. CyprcR- cassis, consequently, intervenes between Harpa and Cassis; and this latter fills up the interval between Cy- prcecassis and Cassidea. Thus, the Cassin (. cated. 3 C Aperture very effuse ; outer lip ) (_ often crenated. J T Ovate ; inner lip spreading, but"} 3 not margined; outer lip thick, £ ) inflexed ; both lips striated andt" (. toothed. J rVentricose; generally tubercu-} •< lated ; basal canal curved^ack- > C wards. J Genera of CASSIN^J. Cassidea. Dolium. Harpa. Cyprcecassis. Cassis. To dilate upon this table, would be almost implying that our conchological readers were purblind. And yet, for those who are not scientific, we may advert to the intimate resemblance which some species of Nassa bear to the small helmet-shells in Cassidea ; so that, but for their size, a superficial tyro would mistake one for the CHAP. III. THE PURPURIIOS. 71 other. Vexilla represents, in outward form, and most perfectly in colour, Harpula vexillum, just as Harpa typifies the crowned volutes. Oniscia and Cyprcecassis are perfect counterparts of each other; while Cassidaria and Cassis complete this system of analogies. If any doubt existed as to the absolute union of Oniscia and Cassidaria in regard to affinity, it is set aside by a re- markable shell obligingly sent me by Mrs. Stuchbury, where the characters of both are united. This is of much additional importance, because it shows that Cas- sidaria does not form one of the five types of the C nal narrow and almost obsolete, j Rapella. Purpura. r Shell ponderous, rough, oftenT •< spired ; basal canal wide, and ?• Myristica. C fully developed. J Ricinula. Pillar, or inner lip, toothed. Cuma. Considering that these sub-families belong to two supe- rior divisions, of which each is the most aberrant type, the coincidence of each agreeing in their details, is not a little remarkable. (65.) The BUCCININ^, or whelks, form the fifth and last division of this family : they are known from the murexes by having no varices, and from the PurpurincB by the pillar not being flattened : they are generally re- cognised by the abrupt termination of the base, which is deeply notched. They are nearly all smooth shells, 74 SHELLS AND SHELL-FISH. PART I. or at least without spines,, or very prominent nodules. The typical genus is Terebra, — the longest spired group of all the carnivorous gastropods, but so closely resem- bling Turritella, that the difference in their apertures alone distinguishes the shells. In the genus Buccinum, the spire is much shorter, and the body-whorl more ventricose. These seem to be the typical groups. The three aberrant will be now described. The first, which appears to us to make the nearest approximation to the wide-mouthed genus Microtoma, is Leiodomus, founded upon two shells, the animals of which have been beauti- fully figured* by M. Quoy. One of these is the Bucci- num l&vigatumof authors; the other, \heB.Achatinum.^ Both these have the foot of an immense size, so that it spreads over a circumference near three times as large as the shell, and is sufficient to envelope it entirely. In other respects there are some slight points of variation between the two; but they do not strike us, at present, of sufficient moment to sanction the formation of sepa- rate genera. To these we add the Terebra vittata J, and three or four other species, apparently undescribed. The vittata, however, appears aberrant, and leads im- mediately to Terebra. We are disposed to consider, also, as the type of another genus ( Trochid}, the species of Purpura of that name, — since its characters will not agree with those of Purpura, while the striated inner lip leads to the conjecture that it is a prototype or Oniscia and similar shells. Lastly, we have, in Tri- tonidea §, a remarkably varied group of small shells, some of which resemble Triton, and others Buccinum; the base, however, is always contracted, and even slightly produced ; the pillar marked at the base with elevated granulations, or short obsolete plaits ; and a distinct canal at the top of the aperture. The connection of this group to Buccinum is very obvious, while its union to Triton * Ency. Meth. pi. 400. fig. 1. f Ibid. pi. 400. fig. 4. J Ibid. pi. 402; fig. 4. § I have since learned that 'this genus is the same as Pallia Gray, —a name I should gladly have adopted, had it not previously been given to a genus of European Lepidoptera, CHAP. III. THE TURBINELLID^E. 7 5 is even more so. Triton clandestinum has the obsolete plaits and the internal channel of Tritonidea ; while its thickened outer lip and more produced channel is suffi- cient to give it a place within the limits of Triton. The circle of the MuricidcB is thus complete; but whether Leiodomus is a sub-genus of Terebra, or really that type which passes into Microtoma, is a matter of doubt ; its analogy, however, to Harpa, as shown in the animal, is a weighty consideration, although we have no interme- diate links by which it is connected to Trochia. (66.) The TURBINELLIDJE form our next great di- vision of the predatory shell-fish. As the Muricidce are chiefly distinguished by the general shortness of the testaceous canal which receives the respiratory siphon, or by its total absence; so may the great majority of the Turbinellidce be known by this canal being considerably lengthened.* The animals, unfortunately, of nearly all the typical genera are as yet quite unknown t; so that we have only a few detached land-marks, as it were, to assist us in the arrangement of their shells. Looking, therefore, to such characters, we observe that the Tur- binellidce, as a whole, are remarkable for the length of the basal canal ; and that the two typical sub-families have the pillar plaited, — a character never met with in the MuricidcK. The volutes, indeed, possess it ; but the total absence of a canal in those shells serves at once to distinguish them. We shall now arrange the whole under the following families: — 1. TURBINELLIN^B, having a large, very heavy, and smooth shell, the canal much lengthened, and the spire generally papillary. 2. SCOLYMIN^J, equally strong and ponderous with the last, but the shell is rough, with foliated spines or tubercles, as in Murex, and the canal short. These two are the typical groups ; the first representing the Cassince, the second the Murlcince of the last family; and both are * Except in the Eburnidce, and some of the aberrant Scolymincs. f Guilding has ascertained that of Scolymus, and Quoy those of Eburna and Strutheolaria : the former has not a probosciform mouth, but the two latter have this structure highly developed. 76 SHELLS AND SHELL-FISH. PART I. furnished with distinct plaits on the pillar. 3. The EBURNIN.E, where the base of the shell is truncate and notched,, the pillar smooth, and the inner lip considerably thickened and spreading. 4. The PYRULIN.&, or pear- shells, having the spire short, the pillar smooth and con- vex, and the canal moderate. 5. and lastly, The FUSING, or spindle-shells, slender and delicate, having the canal, as well as the spire, remarkably long, and generally of nearly equal length. As it will subsequently appear that these groups are of the same rank and value as those of the Cassince, we have given them the same termin- ation in ince, although their contents are by no means so numerous as their prototypes. (67') The TURBINELLINJE are remarkable in their typical genus, — which is TurUnella, — for the excessive heaviness and even the size of their shells, for in this latter respect they almost equal any others of the family. Their surface, although usually smooth, is generally covered with an epidermis : the outer lip is rather thin and simple, but the inner is frequently thickened and margined at its basal half: there are three or four very strong transverse plaits on the pillar, placed nearer to the top than to the bottom of the aperture ; but the uppermost is always largest — not, as in the VolutidcR, the smallest. Like these latter shells, also, the tip of the spire is almost always papillary ; but this part is small, and assumes a very different appearance to that of of the true volutes. The next genus we shall notice — (there being an hiatus in this part of the series, which we shall subsequently advert to) — is Fasciolaria, where the spire is so much lengthened, as to be longer than the canal, — thus reversing the proportion between these parts as seen in Turbinella. The plaits on the pillar are small, placed close to the bottom of the aperture, and generally not more than two ; the last being by far the largest. Some of these large shells are smooth, but a few are corrugated or wrinkled ; thus, preparing us for the Scolymince, to which they directly lead. Two other genera, however, enter into this circle: one of CHAP. III. THE TUBBINELLIX^E. 77 these we designated, on a former occasion*, as the Pyrella spirilla : it so completely represents Pyrula in this group, that no one can mistake the analogy ; while it differs from the old Turbinellce, by having no other indication of teeth hut a sharp ridge along the bottom of the aperture. Following this, we assemble nearly all the fossil Turbinettce under the name of Clavalithes: they form, in our estimation, one of the best defined and most natural groups in malacology ; and our only surprise is, that they never should have been so defined by Lamarck. The species, we believe, are all found in the plastic clay formations. They have hitherto been confounded with Fusus, but they clearly hold an in- termediate station between that genus, or rather sub- family, and the typical Turbinellce, close to which we now arrange them. The Clavalithes, in short, are Turbinella, without plaits on their pillar, and with a more lengthened spire, but the tip of which is also pa- pillary : the smoothness of the inner lip, and the fusi- form shape of the shell, has probably induced authors to place them with Fusus ; but the great size of the body-whorl, the papillary spire, and the thickness and general habit of all these shells, bring them much nearer to Turbinella. Several species occur among the fossils of the Paris basin; and one or two of gigantic size are found at Hordwell Cliff, in Hampshire. We have now indicated four of the types of form or ge- nera, which compose the natural series of the TURBI- NELLIX.E : but there is a hiatus between Turbinella and Fasciolaria ; and this cannot be filled up by any shells which, so far as we are aware, have yet ;been published. As this form, according to our theory, should represent Scolymu* and Murex, we should expect it would have the general shape, and plaits on the pillars, of Turbinella, 'but with the rugosity and perhaps the spines of a Scolymus or Murex. Now, such a recent shell we have a distinct recollection of see- ing, many years ago, in the hands of a dealer ; and we * Zool. 111. series i. 78 SHELLS AND SHELL- FISH. PART I. remember, at the time, being completely puzzled as to what genus it should be placed in, This, of course, was when we were entirely ignorant of those prin- ciples of variation in the Mollusca here developed; but we made a memorandum of the occurrence at the time, conjecturing that it might hereafter be useful. Such we now think it, inasmuch as it realises the very form which is requisite to complete the circle we are now upon. Finally, the long spire of Clavalithes is continued to Turbinella Scolymus *, which differs only in this respect from T. rapa.^ {6S.) The Scolymina, as already remarked, are rough, blunt-spined shells, having the aspect of many of the Linnaean murexes : but'the canal, although short, is straight; the pillar is furnished with distinct plaits, generally central ; while the spire is always pointed. The animal we can fortunately describe from the un- published drawings of our late friend Guilding : the foot of Scolymus is a little longer than the aperture, the the breadth measuring one half the length ; the oper- culum semicircular, and tolerably large, as in Fascio- laria; the peduncles of the eyes very long, the eyes themselves being placed more than half way from the base to the tip ; the anterior part of the foot is truncate, with the angles rounded; the hinder part is also rounded ; the mouth is not probosciform ; and the respiratory siphon is rather short. We cannot make use of this information to the extent that could be wished ; but it will become doubly valuable for comparison, so soon as the animals of Turbinella and of the neighbouring genera are made known. The first form which pre- sents itself in this division, after leaving Fasciolaria, is our genus Plicatella, — an extensive group of small shells hitherto confounded with Fasciolaria and Scolymus. From the first, they are known by the little plaits upon the pillar being almost transverse (as in Scolymus), and not oblique, as in Fasciolaria; these plaits are likewise * Ency. Meth. pi. 431. bis, fig. 2. t Ibid. fig. 1. CHAP. III. THE SCOLYMIN^. 79 much less distinct, and of the same thickness, without the last being manifestly larger ; they are always situated across that part of the pillar which forms the lowest part of the aperture, and not, as in Scolymus, higher up towards the middle; the situation of these plaits, in short, removes the genus from Scolymus, while their form and direction separate it from Fasciolaria. The variation in the shape of the shells is precisely what may be expected from this intermediate position. In such as approximate to Fasciolaria, the canal is nearly as long as the spire ; while in those which lead to Scoly- mus, it is shorter : many of the species, again, put on the aspect of the spindle-shells (Fusus), and hence have been arranged among them'; while others have the exte- rior aspect of Murex. They are all of a moderate or small size; and may be known from the Muricidce by the distinctness of their transverse plaits, the absence of internal tubercular teeth on the inner lip, and their longer channel : they are united to the next genus by Scolymus (or Plicatella) capitellum, — a shell which may be placed in either group without any violation of na- ture : its predominant characters, however, appear to us to be those of the last, inasmuch as the three plates are nearly of equal thickness ; whereas, in Scolymus, the lower are generally much smaller than the upper, and their situation is much higher. This last-named genus is a very striking one, and, being now disencumbered of Plicatella, admits of a much more precise definition than we originally gave it*: the shells are short, excessively heavy; the spire acute, and almost turbinate : the pillar short; the canal straight, and longer than the spire; while the whorls are rugged, and beset with blunt, simply folliculated, or plaited spines. All the species are from warm countries. (69.) There is strong evidence to believe that the natural situation of Cancellaria is immediately after that of Scolymus; for, although the two genera, in their typical characters, are very different, we once possessed * Elements of Conchology, p. 21. 80 SHELLS AND SHELL-FISH. PART I. certain species which exhibited so many intermediate characters, that,, but for the peculiarly small and incurved channel of Cancellaria, we should have been at a loss where to place them : one, we more particularly remem- ber, had an exceedingly wide umbilicus, nearly as large as the Scolymus umbilicaris *, with a very simi- lar shaped shell; and it is not a little remarlAble that, in the figure of this very Scolymus, the base of the pillar, instead of being straight, as in all the other species, is represented as curved inwards, and with an exceedingly small notch, — two characters which are absolutely peculiar, in this group, to Cancellaria. (70.) The fourth genus, Rhinedomus, is typically represented by the Cancellaria senticosus of Lamarck, but of which there are several species. It retains suf- ficient of the characters of Cancellaria to show its true affinity to them, for the exterior surface is longitudinally ribbed, and rough with little points, and there are two distinct folds, or rather one deep groove, at the base of the pillar: but in all essential respects the true cha- racters of Rhinedomus are remarkably different : the basal canal is fully developed, being deeply notched ; and, what is very unusual, there is a distinct, though not a very deep, sinus close to the base of the outer lip. The animal, made known to us by the valuable researches of MM. Quoy and Gaimard, is most remark- able ; but, until we are acquainted with that of Cancel- laria, it furnishes no comparison with them. The other species of Rhinedomus have the spire less elongated, and thus open a passage to our new genus Polytropa, examples of which will be found in two well-known British shells, the Purpura lapillus and imbricatus of Larnarck : this genus agrees, indeed, with Purpura, in common with many other of its prototypes, in having the inner lip flattened ; but the base of the shell, in- stead of being truncate, forms a short straight channel; the spire is always as long (generally much longer) as * Ency. Method, pi. 431. bis, fig. 1. CHAP. 111. THE EBURNIN^!. 81 the aperture ; there is also no internal canal ; the inner lip sometimes has a row of tubercles. The most typical species, however, is the Polytropa crispata. * As we re- cede from this genus, and approach to Plicatella, we find the spire increasing in length ; the numerous crisp undulations give place to small nodules and little tubercles at the base of the inner lip, so that the two genera became united : the circle of the Scolymince is closed ; and this, without the deficiency of a single link in the chain of connection which binds all the five genera together. (71.) The next sub-family, Eburnince, is one of very great interest, since it brings together certain genera whose station has hitherto perplexed us all. For- tunately, however, Mr. Gray has characterized the re- markable little genus Cyllene ; and the possession of other species, joined with those of Rhinedomus, before alluded to, have prevented us falling into some errors : the discovery of the basal sinus, also, on the outer lip of Rhinedomus, at once opens a passage to Cyllene, which still retains a costated and somewhat cancellated exterior, with the basal sinus of the last genus. It deserves es- pecial notice, that the species described by Mr. Gray has a distinct channel round the suture, but the other we possess has not. Now, this variation is precisely what is met with in the genus Eburna, the types of which are channeled, the others not. The slight striae at the base of the pillar in Cyllene, are explained by its analogy to Oliva, just as its obsolete notch typifies its reference to Strombus. Other species will no doubt soon come to light ; so that, with these facts before us, we have no hesitation in placing Eburna as the next type. Between this last, and Struthiolaria, there exists the most intimate relationship in regard to their animals ; both have a comparatively small foot, but a probosci- diform mouth of excessive length, particularly that of Struthiolaria, which, when fully protruded "\, is more * Chemnetz, 187. fig. 1802, 1803. Ency. Meth. pi. 419. fig. 2. f See the animal of Struth. crenata, Voy. d' Astrolobe, pi. 31. figs. 8, 9. 6 82 SHELLS AND SHELL-FISH. PART I. than equal to the entire length of the shell, while the operculum is only rudimentary. A singular unde- scribed shell, just communicated to us by Mr. Stuch- bury, is evidently intermediate between the shape of the shells of Eburna and Struihiolaria ; so that this part of our series is definite. We must now return to Cyllene, for the purpose of showing its close approxi- mation to the fourth genus, Pseudoliva, the type of which is the Buccinum plumbeum of Linnaean authors. The very aspect of this (fig. 3. a) is quite sufficient to show its proximity to ^ 3 Cyllene, and its abso- lute connection with the Folutida by means of Olivillabiplicata (&). Last of all, as forming a passage to the Py- rulcB, we have Lati- axis MawcB* (Sw.), where thechannelround the whorls is so broad that they become almost discon- nected. At first sight, this shell would appear a mon- strosity, did we not remember its prototype, Scalaria pretiosa, not to mention the tribe of TubuUbranchia. We consider it therefore as perfect in its kind, related to all the types we have noticed by its channeled suture, to Eburna by its large umbilicus, and to Rapella (the first genus of the Pyrulince) by something, very difficult to de- scribe, in its general shape. The whole sub-family may therefore be defined as shells whose base is truncate, having a channel more or less developed round the whorls, an aperture contracted at its base, and generally either emarginate as in Eburna, or very slightly notched as in Struthiolaria and Latiaxis : the inner lip is much developed and spreading, without having a defined margin. The following table will also exhibit some of its analogies ; the group, as a whole, being evidently a representation of the Nassince in the neighbouring family of the Muricida. * Griff. Cuv. pi. 25. figs. 3, 4. CHAP. III. THE PYRULIN^!. 83 Analogies of the EBURNIN.E. Struthiolaria. Shell nodulous or muricated. MURICID.K. Eburna. Pseudoliva. Oval, smooth. This comparison explains the relation which Struthio- laria has been thought to have, by some writers, to the murexes : the smoothness of all the Eburnince is remarkable, and is no doubt an indication of their re- lation to the typical Turbinellidts. The lobe of Cyllene, again, is borrowed, as it were, from the Strombidte, in order to show the analogy of both. The excessive short spire of the two next is explained on the same ground ; while the irregular spire of Latiaxis is to be found in no other shells of the zoophagous tribe, than those of the typical volutes or melons. (72.) In the Pyrulince, or the fourth division of the family, we place the greatest part * of those exceedingly diversified shells forming the genus Pyrula of modern writers. They are so designated from their generally being pear-shaped ; the basal portion representing the stalk end of that fruit, and the spire and whorls the other. This comparison, indeed, is so far apt, that it gives a very good idea of the shape most prevalent among them, notwithstanding the great differences they present, in other respects, among themselves. This is one of the few natural groups in malacology, of which we shall endeavour to give as complete an analysis as a long and protracted investigation of their relations will permit. We have invariably found, that where natural assemblages such as this, in any division of the animal kingdom, contain a great number of subor- G 2 84 SHELLS AND SHELL-FISH. PART I. dinate variations, such groups are the best calculated for discovering the true principles of variation. The interchange of characters between one division and another is better marked — the gradations more gentle — the links more perfect ; and hence, by carefully tracing the transitions from one form to another, we have a better chance of correcting our previous errors, and of discovering the fallacy of any preconceived theory, than if the links were so wide apart as to leave the imagination to fill them up, by supposing that they have existed, or that they are not yet discovered, The complete analysis of any one group, where these defi- ciencies do not occur, is far more worthy the attention of the scientific, and even the general, reader, than numberless others whose links are incomplete. (73.) The most striking characteristic of the shells composing this sub-family, next to their pear-shaped form, is that belonging to the inner lip and the colu- mella, or pillar. It will be remembered, that in the Pur- purinfB, the inner lip, properly speaking, is merely a thin glazing spread over that part of the pillar which forms the left-hand side of the aperture : in this respect they differ not from the shells now before us ; but the pillar, instead of being broad, flat, and even concave, as in all the Purpurce, is invariably rounded, and conse- quently very convex : the shape of the Pyrulce, also, necessarily renders the base of the shell much narrower, and the canal much longer, than in their prototypes ; although the degree of length of this channel, as well as that of the spire, cannot enter into the general defini- tion, since it will be seen that these are subordinate cha- racters. The five principal modifications of form under which we arrange all the species, are these: — 1. Pyrula, where the shells are strong and solid ; the whorls ge- nerally muricated; the spire short, yet elevated, well defined, and often slightly papillary ; the inner lip en- tirely wanting; and the canal considerably lengthened. The Pyrula perversa may be taken as the type of this genus, all of which are strong, solid, and muricated spe- CHAP. III. THE PYRULIN>5E. 85 cies. 2. Ficula, where the great elongation of the canal is still preserved, but the shell is differently formed, and its substance very thin. The body-whorl is more or less ventricose, and without any spines or protube- rances; the spire also is so small and depressed, that the shell has very much the appearance of a Sulla, length- ened out at the base ; and there is little or no indica- tion of even the thin glazing which forms the inner lip: such, at least, are the characters of the typical species *, which are few and easily recognised. In P. caudata-f, a new modification of form begins to be developed, — slightly, indeed, but quite sufficient to leave us in no doubt as to the characters of the next genus : this species has the general form of Ficula, but the spire is somewhat more elevated, and the inner lip is so much developed that it begins to have a defined margin at its lower part ; the body-whorl loses nothing of its ventri- cose or inflated aspect ; and the shell is remarkably thin and brittle. It is a fact highly interesting to our present purpose, that there is a shell in almost all re- spects similar to the Ficula caudata (of which it has been described as a variety), but which has a decidedly short canal. Here, then, is the point of junction so desirable to be established between Ficula and our new genus Rapella, typically represented by the Ficus rapa of authors.^ The spire, although pointed, is still re- markably short, and almost turbinated ; the body-whorl equally ventricose with the last, but the lower portion is no longer lengthened — it becomes very short, and, by the more sudden contraction of the aperture at the basal point, the canal becomes so very small as almost to be obsolete. From the absence of the inner lip in the last two genera, the shells have no umbilicus, but in Rapella both these characters are apparent ; the umbi- licus is usually very large, while the base of the inner lip is partially or entirely reflected over it. The sub- stance of these shells varies according to the species, and * Pyrulaficus Lam. Ency. Meth. pi. 431. fig. 1.: fig. 2. is another species, t Ency. Meth. pi. 436. fig. 1. c. I Ibid. pi. 434. fig. 1. G 3 86 SHELLS AND SHELL-FISH. PART I. each presents a graduated link between the thin and brittle Ficula papyracea and the strength and solidity of the other types. The whole of the Ficulce are smooth, except one species*, which has some very slight tubercles; but in Rapella, these tubercles, where they exist, begin to put on that foliated structure so prevalent in the next genus ; and in others there are indications of longitu- dinal plaits upon the body whorl : the outer lip, how- ever, is still very thin, and the whole may be described as a group of generally smooth shells : in one or two species, the inner lip is so much developed at its base, as actually to fill up and cover the umbilicus. Yet, in all the variations we have enumerated, the chief generic characters are constant, arid the basal canal is always small. (74.) We now come to the fourth type, or the genus Myristica, — a name we exalt from a specific to a generic signification for the shell now known as the Pyrula my- ristica, and which we shall here call Myristica coronata. These are the most dissimilar from the typical groups we have yet noticed : the form indeed, somewhat pear- shaped, — inasmuch as the spire is not longer than the contracted part of the aperture, from which the canal may be said to commence ; but they have nothing of the lightness or the basal elongation of Pyrula and Ficula, or of the effuse aperture and contracted chan- nel of Rapella. They may thus be described as very short, strong, fusiform shells; the umbilicus either entirely or partially concealed ; the outer surface armed with muricated and semi-foliaceous spines, and marked with transverse striae ; the inner lip vitreous, but thin ; the outer lip with an ascending channel above, and a wide and distinct one at the base. Now, between this and the last group there is a series of connecting links which unite them in the most perfect manner to each other ; few of them, however, are figured in the more general conchological works. We may here remark, that the P. hippocastanum and lineata t of Lamarck are * See Sowerby's Genera. f Ency. Meth. pi. 432. fig. 4, 5. „ . CHAP. III. THE PYRULIN^E. 87 typical examples of Myristica; while the well-known Py- rula melongina, from having a much wider aperture, puts on something of the characters of Rapella. There are, in fact, many other species ; hut of our last genus Cuma there is only one that we are yet acquainted with, which can he termed truly typical : this we have named C. sulcata (fig. 4.). Its characters may he simply de- scribed as shorter, hut more gra- dually fusiform, than the last, — the middle of the pillar heing crossed by a single transverse and very prominent fold : this cha- racter is altogether without pa- rallel in this sub- family j and dis- tinguishes this type, at the first glance, from all the others : the form of the shell is much more slender at its two extremities than any of the Myristica, and, although much shorter, its aspect at once reminds us both of Fusus and of Plicatella. Nevertheless, although this shell, from having a distinct pkit upon the pillar, seems to us the true type of the connecting genus be- tween Pyrula and Fusus; it is quite evident that the common Pyrula carnaria *, and the more rare P. canaliculata Sw. t, so closely agree with the foregoing definition, that but for their smooth pillar, and the greater elongation of their base, they would both enter into the same genus. In one point of view, it may be said that these very characters, which preclude their ad- mission into Cuma, may yet bring them within the con- fines of Pyrula; so that, being followed by such shells as P. carica J, &c., we come again to the typical genus with which we began the series ; and yet, on the other hand, we may suppose these dubious species, to form the first genus of the Fusince, connecting that sub-family with the Pyrulce by means of Cuma. In either way, however, * Ency. Meth. pi. 424. fig. 3. t Ibid. pi. 424. fig. 2. % Ibid. pi. 433. fig. 3. G 4 88 SHELLS AND SHELL-FISH. PART I. there is abundant evidence, even if these species are omitted, that the Pyrulince form a circular group, in which scarcely a link is wanting. This will be more evident upon arranging the whole of the genera in a tabular form, and placing the few species we have already named in the natural series of their succes- sion. Genera of the PYRULIN^B. List of the Species, showing the progressive Change of one Genus to the other. ftuba. Ency. Meth. pL 42& fig. 2. perversa. Ib. fig. 4. I candelabrum. Ib. pi. 437. fig. 3. : pi. 438. fig. 3. PYRULA H carica. Ib. pi. 433. fig. 3. I canaliculata. Ib. pi. 436. fig. 3. I spirata. Ib. pi. 433. fig. 2. (.Burdigalensis. Sowerby's Genera, fig. 2. rtricarinata. Ib. fig. 3. ,, „ , J ficus. Ency. Meth. pi. 432. fig. 1. CUL& 1 reticulata Lam. Ib. pi. 432. fig. 2. Ccaudata. Ib.pl. 436. fpapyracea. Ib. pi. 436. fig. 1. TJ.O^TT* 3abbreviata- Ib. pi. 426. fig. 2. KAPELLA SefflisaSw. Ib.pl. 434. fig. 1. (Pyrula Rapa.) (. neritoides. Ib. pi. 435. fig. 2. fmelongina. Ib. pi. 435. fig. 3. a. — d. ,, ) lineata. Ib. pi. 432. fig. 5. MYRISTJCA -j coronata Swv Ib. pL |32. fig. 3. „, b. (.hippocastanum. Ib. pi. 432. fig. 4. CUMA sulcata Sw.— followed by Pyrula tuba, &c. (75.) The strong resemblance of the Pyrulince to the Purpurinee is a constant subject of remark among conchological writers, and is so strong as to be often exceedingly perplexing. We now allude only to the latter group, as left by Lamarck ; but many of these are so like our genus Myristica, that it is only upon close inspection their distinguishing characters are detected. Now, this strong resemblance can be accounted for in two ways : first, by supposing that the two groups re- present each other generally in their own respective circles ; and secondly, that this strong analogy actually extends to the particular genera of each sub-family. CHAP. III. THE FUSING. The best way, therefore, of testing this theory, is to place these groups in separate columns, and to examine the result. Analogies of the TUBBINELLID^ and the Sub-families of TurbineUicUe. TURBINELLIN^E. SCOJLYMIN.E. FuSININjE. PY RVLITSM. EBURNIN^E. Analogical Characters. f Shell large, ponderous, heavy, and 7 £ mostly smooth. J f Shells rough, muricated, and ge- ? i nerally spined. J ("Body of the animal, and spire of? i the shell, excessively long. J r Spire always shorter than the} -J aperture; the pillar straight and > L smooth. J Base and canal very short ; inner "i lip generally formed by a thick £ Sub-families of Muricidte. GASSING. MUBICIN*:. BUCCININ.E. PURPURIN;E. C Base and c < lip genei C enamel. (76.) Without enlarging upon the evident traces of a systematic series of analogies, running through the dif- ferent groups here brought into juxtaposition, it is at once seen that the Pyrulince and the Purpurince actually come opposite each other : and having already shown (73.) how intimately their genera correspond, we may pass into the next division. (77.) The FUSING are our last sub-family, and are composed of those numerous shells arranged in the genus Fusus of Lamarck, and are the most elegant and delicate we have yet noticed. Their general form is that of a spindle, tapering very much at both extremi- ties : hence the spire is very long ; and as this contains the body of the animal, the circumstance forms a ge- neric character, both for the mollusk and its shell. The canal is almost invariably long, and generally equals the spire, while the basal volution is typically small : the pillar is constantly destitute of any appearance either of plaits or teeth, and the tip of the spire is acute : this latter character, more especially, separates them from the Turbinellince, where there are, in the aberrant 90 SHELLS AND SHELL-FISH. PART I. genus Clavalithes Sw.*, several shells of an equally fusi- form shape,, hut having the tip of the spire papillary. The shape of the Fusince, and the elongation of the body, render them very distinct from the Pyrulince, excepting at that point of junction where the two groups are united. Nothing satisfactory is known, so far as we can discover, of the general nature of the animals. (78.) The Fusince being thus defined as a whole, we may now proceed to the series of the genera, and their peculiarities. — 1. In the first or typical genus Fusus, the spire and channel are both very much lengthened, and remarkably slender ; the outer lip generally cre- nated, — the indentations corresponding with the internal striae. — 2. Chrysodomus, distinguished from the last by the comparative shortness of the basal channel, and the ventricose or enlarged shape of the body- whorl. The beautiful orange mouthed wilk of England is a typical example ; and the few others, now known, are all of a large size, and chiefly found in northern seas, where they represent the more elegant Fusci of tropical latitudes : the outer lip is always thin and smooth. — 3. Leiostomus, where the body -whorl is still larger than the last, while the spire, although remarkably short, is acutely pointed ; the inner lip is highly polished, and the contracted base of the shell is equal, or rather longer than the aperture j the outer lip, like that of Chrysodomus, is thin and sharp, but thickened within. All the species of this form we have yet seen are fossil, of which the Fusus bulbiformis'V is one of the best and most common types: the outside and the mouth of these shells are always smooth ; hence their generic name. — 4. The next genus we have named Strepsidum, from the twisted shape of its tail or channel : the form of these shells is very much like the last, but the base or channel is equal with the spire, and is turned in an oblique direction ; the outside * We had originally called this genus Clavella ; but as this name may be thought tou closely resembling, in sound, those of Clavagella and Clavatula (Lamarck), we now substitute another, — more appropriate, indeed, as all the species we have yet seen are fossil. t Ency. Meth. pi. 428. fig. 3. CHAP. III. THE FUSING. 9 1 also is marked by distinct longitudinal ribs, and has a coronated row of little mucronate spines, much like those of the harps : the type is the Fusus ficulneus, a fossil of Grignon.* — 5. and lastly, we come to those large species represented by Fusus colossus, coronatus, Morio, &c., which we have arranged in the genus Hemifusus; they are, indeed, only half fusiform, as the spire is shorter than the aperture : they are also distinguished by an internal canal, and the whorls are coronated with compressed spines : it is easy to perceive, by the very aspect of these shells, that they form the passage to the Purpurce ; and their relation is so close, that, until we know something of these animals, we feel somewhat uncertain as to the station of such species as carnaria and Cochlidium. Hemifusus, thus standing between Strepsidura and Chrysostomus, completes the circle of the Fusince. (79-) Upon taking a general view of these shells, we cannot but observe, notwithstanding all their modi- fications, that the predominant characters of the group, more or less, are preserved. In all of them we find shells more or less — equally or unequally — fusiform ; that is, their thickest part is in the middle, and their two extremities attenuated to a point. No teeth, either marginal or internal, are ever seen on the outer lip, while the inner is invariably smooth : the spire, except in one type, is always longer than the basal canal ; whereas, in the Pyrulinfe, the very reverse of this takes place. It has often been remarked by our leading zoologists, — and we have repeatedly illustrated the truth of the position, — that no groups, whether generic or otherwise, are so natural and so demonstrable as those which are linked to others by intervening gradations of form. This is, indeed, completely opposed to the old opinion formerly entertained, that no such divisions should be tolerated in systems, but such as were distinctly separated from each other; or, in other words, that, so soon as the * The Fusus heptagonus (Ency. M£th. pi. 428. fig. 7.) probably belongs also to this genus, — although as an aberrant species. 92 SHELLS AND SHELL-FISH. PART I. links which connected two genera were discovered, the two should be thrown into one. Experience, however, setting aside all other considerations, has long ago con- signed this dogma to oblivion, and has even obliged its warmest advocates to renounce it. Every day, almost, is bringing before us, — particularly in the invertebrate animals, — not only forms altogether new, but such modi- fications of those we already have in our collections, that in a few years we may fairly anticipate not one in ten of the testaceous genera, now apparently isolated, will remain so ; the links which unite them to others will be discovered ; and thus, had we continued to unite one genus to another in the fashion above adverted to, we should be now fast approaching that simplicity of nomenclature which would class all shells under one genus, — the genus TESTACEA. It is only by following out a theory of this sort, and seeing to what it would lead in a general and extended application, that we can judge of its philosophic soundness or of its practical utility. (80.) All the types of the Fusina, as will now be shown, have their representatives in the Pyrulince. Analogies of the FUSING and the PYBULIN^J. Genera of the FUSINJE. ffemifusus. Fusus. Chrysoiomus. Leiostomus. Strepsidura. Analogies. Genera of the PY RULING. ("Trapeziform, or sub-fusiform;? r m I channel short. j ("Channel remarkably long; the 7 (_ whorls generally angulated. J Channel moderate. f Spire very short ; the basal whorl"! t large and ventncose. 5 rThe base of the pillar slightly } -j turned outward, the exterior > Myrisiica. C rough and mucronate. J Ficula. Rapella. The first of these resemblances, or that between Hemifusus and Cuma, is obviously, an affinity, since the most inexperienced student can perceive that these two groups pass into each other. The greatest elongation CHAP. III. ANALOGIES OP THE FUSING. of the basal channel takes place among the Fusince in Fusus, and the like character among the Pyrula in the opposite column ; while in Chrysodomus and Ficula this part is but of moderate length. Strepsidura is the only genus in the first column, which, by its lon- gitudinal plaits and prickly tubercles, corresponds to Myristica ; while the inflated shape of Leiostomus im- mediately reminds us of Rapella — its prototype among the PyrulincB. (81.) Before taking leave of the Fusince, it will be interesting to ascertain how far the genera put on the aspect of those composing the Turbinellints, more par- ticularly as, the former being the last, and the latter — Turbinellince — the first with which we commenced, it follows, as a necessary consequence of the circularity of the whole family, that these two divisions join, and blend into each other. This, we think, will be very evident, upon examining the following table : — Analogies of the TURBINELLIN^ and the FUSING. Genera of the TURBINELLJE. Turbinella Lam. Parian, Lam. Clavalithes. . Ann1naif,, - Analogies. Typical of their respective groups. Sub-typical. Genera of the FUSING. Fusus. Chrysodomus. ' j Remarkably smooth; the spireT and aperture of equal length ; >- the pillar straight. j Leiostomus. (82.) It would hardly be necessary to repeat, in this place, the fact we have so of ten adverted to and illustrated in former volumes, regarding the analogies of typical groups, were it not highly probable that they have not met the eye of our conchological readers. It is there- fore, perhaps, necessary to apprise them, that the re- semblances between the typical divisions of two groups, when thus brought into comparison, are almost always 9 SHELLS AND SHELL-FISH. PART I. more remote and faint than those which relate to the aberrant divisions, — and for this simple reason; — the typical groups are furthest apart from each other ; while the aberrant ones, by which they are connected, are consequently nearer. In this branch of science, moreover, the difficulty of discovering the analogies of typical groups is still further increased, when, as in the present instance, we are without that precise in- formation on the animals, which might furnish us with some analogical points of resemblance. Besides, it must always be borne in remembrance, that our ar- rangement is riot built upon these analogical compa- risons, but upon absolute or presumed affinities, the result of minute analysis. Whatever coincidences, therefore, arise on comparing the different groups, are more properly the result than the cause of their ar- rangement. Analogy is thought to be of the highest importance for the verification of a natural group, but it must always be subordinate to affinity. Applying these general remarks to the two typical groups which stand first upon our list, it will be remembered that one, intervening between TurUnella and Fasciolaria, has never been made known. Passing these, however, and comparing Fasciolaria and Hemifusus, we find they are almost precisely of the same shape and pro- portions ; and that the shells can only be distinguished by one having the pillar plaited, and the other smooth. The very name of ficulneus, given by authors to the type of Strepsidura, shows its analogy to Pyrella, and consequently to Pyrula ; it is, in fact, completely a pear- shaped shell. The resemblance of Clavalithes and Leiostomus is equally striking : both are remarkably smooth shells ; with the channel lengthened, and the basal volution more or less enlarged ; both are fossil genera of the same strata ; and although Clavalithes in general possess very small plaits on the pillar, and a papillary spire (without which, in fact, the genus could not be clearly defined), yet there are one or two species having the pillar, as in Leiostomus, perfectly smooth. CHAP. III. MUBICID^J AND TURBINELLID.E. If the reader turn to the figures of Clavalithes longcevus, clavellatus, scalaris, Noa, and rugosus*, and to that of Leiostomus bulbiformis f, he will at once perceive their mutual affinity much better than from our description. (83.) Having now supplied all the details in our power respecting the two great families of the Zoophaga, or predacious shell-fish, — and which, in fact, stand at the head of the entire class of TEST ACE A, — we shall lay hefore our readers the following diagram, which will explain, more distinctly than our usual tables, the circular affinities of each of these families, and the cor- responding analogies of their sub-families. 1 Mnricina 2 Cassin MURICIDJE YTURBINELLID^ 5 Buccinineedp Fitsince 5 4 PurpurinteQL. — ±Qpyrulin t cate. 3 ( VolutiiKE and Cassirus.) Foot small, not so long as the hell, the base of which is con- rFo< 1 \ racted. (Mitrirue and Scolymus.) {Spire very short ; tip papillary ; > pillar plaited. J Spire nearly or quite concealed. f Outer lip detached and thick- ? i ened. j Muricidce. Turbinellid*. Volutidce. Cyprtsid.ee. Strombidce, Thus, the truncated and wide-mouthed helmet-shells, among the Muritida, find their prototypes in the melon volutes ; and the muricated mitres, in the sub- typical Turbinellida, with which they also agree in their fu- siform shape. The Olivince correspond to the typical volutes, in having their foot excessively large. The ani- mal of Ancillaria is unknown ; but, from the high polish of the shells, we may suppose it is analogous to the cowries. Lastly, the Marginellince are clearly proto- types of the StrombidfSj as they are the only volutes which have the top of the outer lip detached from the body- whorl. (89.) The weakest point in the foregoing table is that, perhaps, which relates to the AncillaricB ; but, by comparing the family with the Cassidce, the station of this group will be more clearly shown. * The annexed cut is from one of the unpublished drawings of Guilding; the shell is pure white. H 2 100 SHELLS AND SHELL-FISH. PART I. Analogies of the VOLUTIDJE and the CASSID.E. Sub-families of Sub-families of VoLUTiaE. Analogical Characters. CASSID.E. Typical Genera. Typical Genera. VOLUTA. Smooth j spire[short ; base truncate. CASSIS. MITRA. r Aperture very wide ; the base of f ANCILLARIA. < the pillar often thickened and >- PURPURA. i striated. 3 „ CA thick deposition surrounding} MAOC. MARGINELLA. £ the aperture of the shell. j This table illustrates what has been often shown among the vertebrated animals, — that, to establish the analogies of two given groups, they must often be traced through the medium of other groups : thus, the Ancil- laria, in one respect, are prototypes of the Cypraa; and in another, by their wide aperture and striated base, are equally so to the Purpurce. Again, if it was asked,- — What shells among the volutes have a marked resem- blance to Concholepas and Monoceros ? every natural- ist would point to Ancillaria ; for all three have a very wide aperture, and a distinct prominent tooth at the base of the outer lip. This is conclusive evidence ; and it therefore follows that the analogy between Ancillaria and Cyprcea, however obscure in a direct way, is ren- dered plain by being traced through the medium of the Purpurinfe. The other analogies in the table are so palpable to the zoologist, that they require no illustra- tion. Hence it follows, as a natural result of this com- parison, that the Volutida, in like manner, represent all other of the circular groups in the zoophagous tribe. (90.) Our next object is to show that the Volutidce, as a whole, form a circle of affinity. It is clear that the pre-eminently typical volutes, or melon-shells, branch off into two separate series ; — one leading to Scaphella, through V. magnified, fulgetrum, papillaris, and fusL CHAP. IV. CIRCLE «1F VdDUVIDJSB- formis ; the other to CymUola, or the muricated volutes. From this latter, therefore, we shall begin to trace our circle ; because, even here, we have evidently a repeti- tion of the analogy between the smooth helmets and the spined murexes. After the Cymbiolce, or muricated volutes, succeed such as have the spire elongated, and the plaits upon the pillar numerous : among them is the Valuta lyriformis ; and this brings us at once into the sub-family of the mitres : from these the passage to the olives is rendered so gradual, by Mitrella in one, and Olivella in the other, that the mere systematist will hardly admit these genera, because they blend into each other. Hiatula is in the same predicament : by its wide mouth, and the thickened base of its pillar, it is all but an Ancillaria; so that the junction is here also complete. There remains, then, only the Marginellte, which are so like some of the Ancillarice, that we may safely place them as next in the series. What group then succeeds ? The illustrious Lamarck considered the well-known Voluta Zebra (fig. 7- «) of our catalogues to be so like a Marginella, that he has actually placed it in that genus: and the affinity between this shell and Scaphella maculata (6) is immediate : we thus pass to the S. fulgetrum, and again reach the typical volutes. Thus, by a different route, we return to the point from which we started, without a link in the chain being wanting. (91.) We have thus shown that the Volutidce form a perfect circle of affinity ; and that the divisions we have thrown them into are strictly natural, because they are prototypes of all the others in the zoophagous tribe. Each of these primary groups, or sub-families, will now be examined in detail, in the order in which they na- turally follow ; viz., the VOLUTIN^:, the MITRINJE, the OLIVIN^E, the ANCILLARIN.E, and the MARGINELLIN^:. H 3 ,1$^ ^ i SHELLS AND ^HELL-FISH. PARTI. (92.) The VOLUTIN^ or volutes, are immediately distinguished from the mitres by being more ventricose shells, -with a much shorter spire (as in Valuta Olla, Jig. 8.), the apex or point of which is more or less thick and papillary. These characters are developed in their highest perfection in the smooth and coronated melon-shells, to which, as being the pre-eminent types of the whole family, we are compelled to retain the sub-generic name of Valuta. Nevertheless, these cha- racters are greatly modified in the five leading genera, which we characterised and illustrated several years ago ; and time has only con- firmed us in the views we then took on the subject. We accordingly arrange the whole of the Lamarckian volutes under five leading genera. 1 . Valuta, — having the spire excessively short, thick, and invariably smooth; the suture of the body-whorl being generally covered with a vitreous deposition or glazing, never seen in the next genus. 2. Cymbiola, — having the body- whorl less ven- tricose, and the spire longer ; the apex not near so thick ; while, in all those species which are coronated, the whorls are marked with tubercles. In both these groups, the plaits are almost invariably four, — the upper ones very thin and small, while the lowest is nearly double their thickness. This structure of the plaits, it may be here observed, belongs alone to these two typical genera. The third genus is Harpula, where the plaits upon the pillar are very numerous, — the upper ones remarkably slender, but gradually increasing in size and thickness, until the last, or the two last, which suddenly become smaller : the terminal whorls of the spire, although still papillary, are much more slender. The form of the spire, however, undergoes a change in this group, and is therefore of secondary importance. This gra- dual diminution of one of the typical peculiarities of the VolutincB prepares us for the fourth genus, Volu- tilithes, where the apex is perfectly regular and acute. CHAP. IV. CHARACTERS OF THE GENERA. 103 This is one of the most natural, and, at the same time, interesting groups ; for no recent species has yet been found. The upper and finer plaits upon the pillar, so characteristic of Harpula, now disappear, and leave only one or two, or perhaps three, of the larger ones at the base : the number of these plaits, in fact, varies according to the proximity or the remoteness of the species to Harpula. The general shape is fusiform, the whorls being strongly coronated with spines, and often marked with transverse elevated ribs. The fifth and last genus is Scaphella, where the upper plaits of the pillar are as large as, or even larger than, the lower ; the outer lip, also, is thickened within, and the suture of the whorls is covered by a glazing of enamel. All the species yet discovered are smooth ; and from the high polish with which many are covered, there is every rea- son to believe the animal has a strong affinity to that of Marginella: this, indeed, is so obvious in the shells them- selves, that Lamarck, as we before observed, has placed the Scaphella Zebra (jig. 7. a) in that group. The form- ation of the spire in general is conic, obtuse, but hardly papillary ; but in certain aberrant shells, as S. fusifor- mis and papiilaris, the apex becomes thickened, and assumes all the characters of the true volutes, and thus unite with the melons by means of V. magnified. (93.) By these typical characters, it appears to us that the natural and primary divisions of the La- marckian volutes are regulated. In this, and all similar investigations, we have found it necessary to discard all theoretical notions as to what should be the primary types. No ordinary degree of impartiality is necessary for accomplishing this ; because every naturalist, more or less, is prone to form certain preconceived notions as to what he thinks should be the types of any particular family ; and thus, prejudiced in favour of some hypo- thesis, he sits down to his task, exactly in that frame of mind the most unsuited for the investigation of truth. We candidly confess that many years ago, when this H 4 104 SHELLS AND SHELL-FISH. PART I. family first engaged our attention., we imbibed a notion that the formation of the spire was the chief, if not the only, character upon which they should be arranged : we soon, however, threw aside this, and fancied the same importance attached to the number of plaits : equally dis- satisfied with this theory, we finally resolved to combine all these characters, without giving to any one a para- mount importance : having done this, we soon perceived that these groups turned out to be representations of all those in the entire family ; and this discovery prevented our falling into many errors, which would otherwise have been inevitable. We may now consider each of these genera in further detail. (94.) The pre-eminent types of the genus Valuta, for reasons subsequently stated, are such shell-fish as have the spire small, and so slightly developed, as to be all but obsolete. This we see more especially in Valuta Nep- tuni, Porcina, and Cymbium (fig. 9. a) where nearly the whole shell being enveloped, as it were, in the body-whorl, gives to it, in all but the plaited pillar, the perfect ap- pearance of a Sulla. The very slight elevation of the spire is, therefore, one of the typical characters of this genus ; but it is not the only one : the spiral whorls, which end in the apex, whenever they are developed, are remarkably thick, and are always perfectly smooth, although the body- whorl may be coronated ; whereas in the next genus, Cymbiola (C. vespertilio, fig. 9- 6), these spiral whorls are always plaited (c). There is a solitary CHAP. IV. TYPES OF THE GENUS VOLUTA. 105 exception to this form in the true volutes, which is seen in Valuta angulata, where the spire is absolutely pointed : this exception, however, is a necessary one, for other- wise there would be no species which would represent Volutilithes. The exterior of all these shells, so far as we yet know, is covered with a thin epidermis, except, perhaps, P. proboscidalis ; so .that, notwithstanding the enormous foot of the animal, it does not appear that any part of the shell is covered by that member. The chief variations among those shells are as follows: — First, the melons, whether smooth or coronated. Secondly, the horned volutes, where the form is less ventricose, and the body- whorl armed with long spines, as in impermlis and chrysostoma *, both being connected to the coronated melons by Broderipia and marmorata. The third type is the V. Scapha, having the outer lip, as in the StrombidfB, considerably angulated and dilated. The fourth type is the V. angulata, whose aperture is very ef- fuse ; and the spire very short, but pointed. Lastly comes the Voluta magnificaauidfulgetrum t, where we once more have the egg-shaped and inflated form of the melons, together with their very thick apex, totally different from that of the Voluta ancilla, &c., with which authors have hitherto placed it. The Voluta olla and rubiginosa follow this type, and blend it, in the most perfect manner, with those we first enumerated. (95.) The passage from VOLUTA to our next genus, CYMBIOLA, is opened by the rare V. mitis of Lamarck ; which, by its general smoothness, its thick spire, and a slight separation of the top of its outer lip from the adjoining whorl, evinces a close affinity with V. Scapha. The volutes now before us differ from the former, in being stronger, less ventricose, and having their spire much more lengthened : their whorls are angulated, and are mostly armed with acute spines, or * Exotic Conch ology. t " In size and form this shell approaches nearly to V. magnified." — Tank. Cat. p. 28. 106 SHELLS AND SHELL- FISH. PART 1. small tubercles. Their great distinction, however., lies in the apex of their spire, which always exhibits the incipient developement, in the shape of tubercles, of those spines which may be on the body- whorl. The com- mon Cymbiola vespertilio(fig. 9« 6) is the type of the whole genus. From these to the next division, represented by Cym. pacifica, gracilis, &£., the gradation is easy and 'natural. Never theless, these Australian shells constitute a distinct division ; for they are known at once by the greater prolongation of their spire, which is nearly equal to their aperture, and by the majority being only tuber - culated : the apex is always obtuse and slightly papil- lary. Whether we should con- sider the F. ancilla (fig. 10.) as a distinct type of form, is uncertain, but it possesses a peculiarity of aspect, which seems to detach it from those last alluded to : the very slender shape of its apex, however, smooths the passage to the V. braziliana of Solander, • — remarkable not only for its pointed spire, and its ventricose shape, but from possessing, like V. angulata, only three plaits to the pillar. It is clear that this, as well as C. mitis, are aber- rant forms. (96.) In the next genus, HARPULA, the form of the apex, which is the main character of Valuta, became somewhat variable in Cymbiola ; but in this genus it is so uncertain, that it must be regarded only as of se- condary importance. The numerous plaits, which ex- tend the whole length of the pillar, are the most certain distinction of Harpula, which is also a more numerous genus than the last. Of the two primary types, one is seen in H. vexillum, which is smooth, with a papil- lary spire ; the other, seen in H. hebrcea (fig. 12. 6, in p. 108.), is muricated, with the tip of the spire obtuse, re- gular, conical, and hardly enlarged. There are, however, other shells, obviously belonging to this group, which will not arrange with either of these two divisions. One, CHAP. IV. HARPULA, VOLtJ T1LITHES, SCAPHELLA. 107 the Harpula fulminata, has much the shape of a Fascia- laria, but with the top of the outer lip slightly angulated and dilated, something in the same way as Valuta Scapha and Cym. mitis. The enlarged, knob-like form of its apex immediately reminds us of Valuta papillaris; while in its markings, and in the thickness of the outer lip, internally, it perfectly resembles Scaph. undulata. The numerous plaits, however, clearly show it is a Har- pula. Another, our H. lyriformis, is the only recent volute whose spire is longer than the aperture ; and a third aberrant type, the H. buttata, stands at the con- fines of this genus, and forms a passage to the next. (97.) VOLUTILITHES, so far as is yet known, is a genus found only in a fossil state ; unless, indeed, Va- luta nucleus Lam., peculiar to the Australian seas, be considered as coming within its limits : it exhibits none of the delicate plaits on the pillar of Harpula ; so that one half of its characters belong to that genus, and the other half to this. The typical characters of Volu- tilithes have already been detailed (92.) ; and as we shall particularly notice the subordinate types hereafter, we may pass onward to the next group. (98.) The last of the primary divisions is the Aus- tralian genus SCAPHELLA ; the best known type being the Scaphella undulata (fig. 11. a). All of these hitherto discovered, are natives of the South Pacific Ocean. We are not aware that any of these shells have an epi- dermis, and their uniform smoothness leads us to con- clude they are partly covered by the dilated lobes of the 108 SHELLS AND SHELL-FISH. PART I. mantle, as in the Olivince. This,, in fact, is the only genus which is neither spined, muricated, nor tuberculated. The spire (6) is conic and somewhat short ; the whorls of the apex are scarcely papillose ; while the inner margin of the lip is considerably thickened. The plaits on the pillar, as to number, are by no means constant, even in the same species ; in general, there are four, but the last is always the smallest. Sometimes, however, the pillar, at this part of the aperture, is thickened, and there are five or even six plaits confused and irregular*, as in S. papillaris (Jig. 12. a). This latter type is remarkable for its apex, which is suddenly enlarged into a thick nipple- like form (6), similar to Harpula fulminata, and very much like the published figure of Valuta fulgetrum. From this, it is clear that we have again arrived, almost unconsciously, among the aberrant forms of the melon volutes j for fulgetrum connects papillaris to magnifica, which, with the form of fulgetrum, assumes, as it were, that particularly large spire which is the chief character of the genus Valuta. Scaphella papillaris, on the other hand, is closely connected to our S. fusiformis, which thus unites it also to S. undulata. (99.) Here we close our remarks on the affinities of these magnificent shells ; but, before we enter upon the consequences of this distribution, we shall endeavour to meet some objections which may possibly be raised * This deviation is not uncommon in Scaphella undulata : four is the usual number of the plaits ; but sometimes, as Lamarck observes, there are two smaller and supernumerary ones. (Lam. Syst. vii. i. 245.) The same variation is seen in Scaph. Junonia. CHAP. IV. REMARKS ON VOLUTA ANGULATA. 109 against it. First, it may be urged, that, although the series between the smooth melons and such shells as Vo~ luta Scapha is sufficiently obvious, still, that the Valuta angulata can never follow Scapha. This objection seems well grounded, and certainly deserves attention. We admit that angulata has a spire totally different from that structure which we maintain is typical of the group, wherein we have, nevertheless, placed it. But is there anything extraordinary in this arrangement ? Does there exist, in any one class of the animal king- dom, a natural group, wherein all the species exhibit the whole of the typical characters ? Every naturalist, every systematist, knows full well that no such group is to be found. It has been well said, by one of the most distinguished naturalists that this country has produced, that if a species possesses two out of the three characters of the genus in which it is placed, this is all we can expect ; and the reason of this is obvious : if all the species possessed all such characters, then there would be no gradation of structure — no links in the chain of affinity — no loss of one structure — and there- fore no taking up that of another. Now, all this is diametrically opposed to facts ; for the whole creation is but one connected chain of such graduated progressions, — unequal, indeed, yet still graduated. The affinity of Scapha to angulata is not so intimate and direct as many others in the series ; but this is nothing to the purpose, — because, as we have just said, affinities may, and do, vary in degree : the question is, whether, be- tween these two shells, there is a sufficient resemblance to constitute any degree of affinity ? When we compare the angulated apertures, the form and proportion of their plaits*, and the thick enamel spread over their spire, we see an affinity which to us is unquestionable. If angulata, in short, had a papillary spire, instead of a pointed one, it would be of the same type or sub-genus as Scapha ! the pointed spire, therefore, was necessary * Not their number, for in angulata there is one less. 110 SHELLS AND SHELL- FISH. PART I.' in two respects ; — first, to show that this shell was the prototype of the genus Volutilithes; and, secondly, to se- parate it from V. Scapha. The next type we place after angulataisfulgetrum, with which, also, comes magnified. Now, the complete glazing of angulata (which shows the great size of the animal's mantle) is partially car- ried on tofulgetrum, which Mr. Sowerby thus describes : — " The left lobe of the mantle of the animal must have been very large, since the columella lip is extended so as to cover half of the lower volution." And that this shell exhibits a further affinity to the slender spire and angulated body-whorl of angulata, is evident on the same testimony.* Evidence of this sort, from an un- prejudiced writer, is the very best that can be produced, since it is given without any idea of the use it may be applied to. (100.) Our arrangement of the Lamarckian volutes, being thus founded solely upon affinity, would seem to require no additional corroboration ; but beneath the sur- face of this beautiful chain of relationship, lies another, even more interesting, which can be only brought to light by comparing the analogies, which all these vari- ations in form present among themselves. These re- semblances are so remarkable, that we shall now enter upon them very fully. To do this in all cases, even were it possible, might be tedious ; but in the present instance it is almost unavoidable, inasmuch as we desire that our theory on the laws of representation among the TESTACEA should stand or fall according to the success or failure which may attend their exposition in this and the two preceding families. (101.) The principles of natural classification, so fully explained in the second volume of this series, and the innumerable proofs taken from every class of vetebrated animals that have been brought forward in the succeed- * V. fulgetrum " is easily distinguished by its acuminated papillose spire, and by the obtuse angle on the upper part of the last volution." — Sow., in Tankerville Cat. p. 29. CHAP. IV. ANALOGIES OF THE VOLUTID.E. Ill ing treatises, are so well known to the majority of our readers, that it would be superfluous again to repeat them. But before we apply this theory to the group before us, a previous question must be first disposed of, — namely, upon what grounds we determine that the melon volutes are the pre-eminent types of the whole family ? Now, we do not regard this as a matter of speculative opinion ; it must be determined, in fact, by the analogies which the group possesses, as a whole, to other groups. The following table appears to us to decide this question : — Analogies of the ZOOPHAGOUS and PHYTOPHAGOUS GASTEROPODA. MURICIDJE. Typical. HELICID*. TURBINELLID^. Sub-typical. TROCHID.E. ("Foot of the animal excessively") I large ; tentacula very short ; eyes I VOLLTIOB. ,lrn,irina, Purpunna. Spire often excessively lengthened. f Aperture very effuse ; base of the 7 I pillar grooved or plaited. J C Outer lobe of the man tie much di-^ < lated ; representing Marginella, > Nassincc. (_ and consequently Nassa. j In this and the last set of analogies, we again have CHAP. IV. VOLUTA TYPES OF FORM. 113 an instance of that inequality in analogical relations, which, in our former volumes, we have so frequently ad- verted to. This inequality, strangely enough, has been somewhere urged as an objection to the theory of repre- sentation. Such reasoners seem to suppose that, unless all groups possess the same degree of resemblance to each other, the evidence is inconclusive. On this plan, an eagle and a lion may perhaps be admitted as analo- gous ; but a carnivorous insect and a carnivorous beast cannot be so, because the analogy is remote or obscure. But if there are any analogical resemblances in nature, it follows, as a necessary consequence, that such resem- blances are strong or faint, near or remote, according to the proximity or distance, the similarity or the dis- similarity, of the objects compared. Thus it is in the present instance : the groups being remote, their analo- gies are not strong ; nevertheless they are substantially true, — because they are perfectly verified through the medium of other or intervening groups, which, from being more alike, render the analogies, in the same proportion, more obvious or direct. (104,) We may now proceed a step further, and apply the same description of proof to the sub-genera, or types of form,, of the typical genus Valuta, upon the affinities of which we have already said so much. We leave it to be determined by others, whether these types of form should be designated as simple divisions, or as sub-genera, and therefore to be distinguished by a pa- tronymic name. That this will ultimately be done, we have no doubt ; because they are of the same rank as the sub-genera of the other families. The shells which we view as types of form in the restricted genus Valuta, are as follows : — Valuta Neptuni, V. imperialis, V. Scapha, V. angulata, and V. magniftca. We shall now place these in one column, the two extremes of which, as we have already shown, meet, and form a circle : the next column is composed of the genera of the La- marckian volutes, which also form another, circle. Now, if the contents of one represent the contents of the other, V. imperialis. \ duced ; the body-whorl and > Cymbiola. 114 SHELLS AND SHELL-FISH. PART 1. without any variation in the order in which each divi- sion respectively stands in regard to affinity, then all the verification that analogies can possibly give, will have been attained. Analogies of the Sub-generic Types in the Genus VOLUTA. Genera of the Typical Species. Analogical Characters. Volutinac, Sw. or VOLUTA Lam. V Neptuni (Ventricose; egg-shaped; spire] yi ivepiu, i very ghortj or uone J r Sub-ventricose ; spire more pro- ~) 4 duced; the bo" C spire coronated. v c,. !,„ 5" Upper angle of the outer lip ad- \ rjnvn,.in V. Scapha. I vancing up the first spiral whorl, j Harp***. V. angulata. { S%£ythe apCX acute> and not } Volutilithes. rColumella lip thin and muchn V. magnified. s spread; shell sub-fusiform ; > Scaphella. C spire short. j Four out of the five analogies of this table are so clear and definite, that they scarcely require further illustra- tion. We thus see how imperialis represents the bat volutes; angulata, again, puts on the pointed spire of Volutilithes; while magnifica connects Scaphella with the melons. The analogy between Scapha and Harpula (the heavy tuberculated species of the latter being the true types), although less apparent on a cursory view, is still very remarkable. The strong resemblance which V. Scapha bears to a Strombus, must, indeed, strike the most casual observer ; but, we confess, it was some time before we discovered the singular character so prevalent in all the Harpulee, or music volutes, where the outer lip is extended up the first spiral whorl, — a structure so universal among the Strombida, ' or wing-shells, and which is not found in any other group of the volutes. To put this analogy, however, in a clearer, light, we shall now compare the types with the great circle of the Zoo- phaga. CHAP. IV. VOLUTA - TYPES OF FORM. 115 Analogies of the Types of VOLUTA to the ZOOPHAGOUS Tribe. Genera Families p Qfthe Analogies. of the VOLUTINJS. Zoophaga. imperi..!.. Magnifica. Scaphella. Mantle very large. VOLUTIDJE. Angulata. Volutilithes. Scapha. Harpula. { This table brings out two remarkable facts. — The first relates to the analogies of Valuta Scapha and of Har- pula to the Strombidce — all which, by placing these three groups in separate columns, fall in precisely opposite to each other. The second relates to the analogy between the Muricida and the coronated volutes : these are all the most spiny or muricated of all univalves. The same principle of variation holds good between the smooth melons and the typical Turbinellidce : both are remarkably smooth shells ; both have very short papil- lary spires ; and both have three or four well-defined plaits on their pillar. But the sub-typical group of the Turbinellidce are composed of those rough, spiny, and often coronated shells, forming our genus Scolymus: these, therefore, are analogous to the sub-typical genus Cymbiola ; and, consequently, to all such forms or types as represent them, as Voluta imperialis, Harpula hebrcea, Volutilithes musicalis, &c. It seems to be one of the laws of variation in the structure of the zoophagous shells, that every one of the families* should contain two prominent groups ; one remarkable for having smooth, and the other rough, or spiny, shells. It would even seem that Nature, so to speak, is so tena- cious of this law, that she adheres to it in the very smallest of her groups, — that is, in the variations of sub- genera. Among the most common instances, the reader * Except the Cyprceida, where it is obvious, from the little variation in the shells, that the analogies must be traced from the animals only. 116 SHELLS AND SHELL-FISH. PARTI. will call to mind the smooth and the coronated helmets (Cassidea and Dolium}, the smooth Turbinellce, and the murex-like Scolymince, the tuberculated StromU, and the smooth Cones. The same principle, again, is often carried into the variation of each : thus, although the Cones, as a whole, are smooth shells, yet one division has coronated tubercles. Some of the melon volutes are smooth, as V. Neptuni; while others (which are sub- typical) are coronated. Every division, in short, large or small, in the entire family of volutes, exhibits these differences. The reader will of course understand we are now speaking only of the typical and the sub-typical types ; the variation of the aberrant forms being regu- lated by other circumstances, which, in the present state of our inquiries, it would be premature to venture upon. (105.) If the foregoing arrangement of the sub-ge- neric types of Valuta be really natural, it follows that all the melon volutes form but one sub-genus. Break them up into other sub-genera, and give to each the same rank as attaches to the four other types, and the whole harmony and beauty of the theory would obviously be de- stroyed ; their arrangement would then, in fact, become an arbitrary matter of nomenclature. Had our object been to have formed an artificial classification of the Testacea, we should, without hesitation, have adopted the views of others on this subject. The divisions of the smooth and the coronated melons are excellent, because they are natural : but all we have now stated shows that they are two sections only of a sub-genus. It will be evi- dent to those zoologists who may be conversant with the vertebrated animals, that all groups pre-eminently typical contain a greater number of forms than any other, as if Nature intended to show us, at the onset, the rudi- ments of all those variations which were to characterise the surrounding groups. Lawrence, long ago, observed of the Caucasian race of man, — the most pre-eminently typical, — that it contained more numerous variations than any other; and we have shown how strictly applicable this assertion to the vertebrated animals. CHAP. IV. BANK OF THE MELON VOLUTES. 117 Now, the melon-shells, forming our genus Valuta, are of this description ; they stand at the head of the whole family ; and we accordingly find their subordinate types are not only the most varied, but the most numerous. Vol. imperialism Scapha, angulata, and magnifica enter, indeed, into their circle; but they do not form the highest point of perfection. This is seen only in the melons, strictly so termed; yet, even here, how great is the diversity of forms ! We have some with a spire alto- gether hid, and the shell devoid of colour, as in Nep- tuni; others with the indication only of a mis-shaped spire, as in V. Cymbium, yet with marbled variegations : another little assemblage has coronated and vaulted spines ; and even among these, the spire is so varied, that in one, V. tessellata, they are compressed, as it were, over an extremely short spire, which they almost hide ; or, as in diadema, they are long, and directed forwards : finally, there is one (V. Broderipia) which deviates so much in its general shape and habits from all others, that it will not strictly arrange with these coronated melons, or with the next type, V. imperialis. Now, all these variations absolutely occur in the compass of a single sub-genus : and we may explain this diversity by supposing that the coronated melons typify the genus Cymbiola and V. imperialis; that the smooth melons are the true representatives of the whole ; and that the V.Broderipia is an aberrant form connecting the coro- nated melons with Valuta imperialis. That such shells as Valuta JEthiopica are much more perfect (abstractedly) in structure than Neptuni and its allies, is unquestion- able : but this does not imply typical perfection ; for it frequently happens in aberrant groups (as the Volutidce is among the Zoophaga), that the typical character rests on very different considerations. (106.) It will be needless to go into all the details of the next genus, Cymbiola. Yet it will be satisfactory to see how intimately the types represent those of the Voluta, — at least, in their main characteristics. In the following table, therefore, we have selected those species i 3 118 SHELLS AND SHELL-FISH. PART I. which have been already alluded to ; premising only that some doubts hang over the true nature of the type which intervenes between the bat volutes (C. vespertilio) and C. tuberculata, chiefly arising from our not having these shells immediately before us. This point, there- fore, must for the present be left open to doubt.* Analogies of VOLUTA and CYMBIOLA with the GENERA. XtphHll. i^»»Vfa. VQLUTi. Scapha. Smooth ; outer lip angulated. Mitts. HARPULA. Angulata. Aperture effuse; spire pointed. Braziliensis. VOLUTILITHES- Magnifica. {Su^^^Me* apexsmooth,j ^.^toto. SCAPHELLA. Cymbiola tuberculata^, from having a greater number of plaits than any other of its genus, seems to connect Cymbiola with Harpula, through the medium of H. ful- getrum; and at the same time to pass into Cymbiola Braziliensis % ; which last, by its effuse aperture, the acu- minated apex of its spire, and its possessing only three plaits, is a perfect representation of Voluta angulata. (107.) The genus HARPULA commences with the Harpula fulminata §, one of the most interesting forms in the whole family. Its shape is that of a Fasciolaria, the base being produced; while the apex is so papillary that it forms a large knob, almost completely round : it is, in fact, the first, or terminal, whorl which is thus inflated ; and the little turn which this whorl makes is not on the top, but on the side. Now, this formation is only seen in Scaphella papillosa, but it is indicated in * A full investigation of the animals of the Pacific volutes will claim our first attention, after the settlement we intend making on the romantic and prolific shores of New Zealand. f Exotic Conch. t Chemnitz, pi. 176. figs. 1695, 1696. The Valuta rudis,'of which a figure has been published in Griff". Cuv. pi. 30. fig. 1., seems to me a typical melon volute ; but nothing further is said about it, than that it is " clay-coloured mixed with white." § Ency. Meth.pl. 381. fig. 2. CHAP. IV. TYPES OP HARPULA. 119 H. bullata, and a very near approach to it may be traced in Harpula vexillum. We thus have three resemblances ; one of which only we shall at present regard. The numerous plaits of fulminata evince its proximity to vexillum and Lapponica. To these succeed the pre-eminently typical forms composed of Harpula hebrcea, musica, polyzonalis, sulcata, &c., all of which are thick, muricated, or spined. By these a passage is formed to those slender-ribbed species where the two last plaits are decidedly the thickest, and the upper ones either very slender,, as in Harpula lyriformis*; or nearly obsolete, as in Harpula costata^; or perfectly wanting, as in Harpula nucleus. J In the apex of these shell s, how- ever, here is a marked difference, plainly indicating a gradation of structure: thus, in costata and multi- costata §, the apex, although obtuse, is not swelled, and the volutions appear to be graduated equally, as in Har- pula potyzonata. In nucleus, the apex seems almost acute || ; but in H. lyriformis the second volution is swelled and papillary : it is by this shell, therefore, that we may pass to the next type of form, represented by our Harpula bullata1^, where the shell retains the same shape as H. nucleus, and, like that, has only two distinct plaits ; the whole shell is quite smooth ; the spire is not only very obtuse, but the terminal volu- tion is enlarged, even in the worn individual, which is the only one we have yet seen; and its last turn is placed on the side, not at the apex. For this form, however, we have been prepared by the Harpula lyriformis, so that we return again to the singular-shaped spine of Harpula fulminata. Between H. bullata and H. ful- * tool. Journ. iii. pL 3. Zoo}. Illust, first series, pi. 54. t Brand's Journal, xvii. p. 33. $ Mawe's Conchology, frontisp. fig. 2. $ Broderip, in Zool. Journ. iii. pi. 3. fig. 2. |j I am not positive on this, not having a perfect example at this time before me. f The only specimen I have yet seen of this shell is figured in Zool. IU. 2d series, pl.'lS. ; nor am I aware of any other, at least in the London cabi- nets. Papillary spires are always remarkably thick ; and as it was evident this specimen had been beaten and battered on the sea beach, it is highly probable that the apex was originally much more thick and inflated than it was on coming to my hands. It is now in the British Museum. i 4 120 SHELLS AND SHELL- FISH. PART I. minata we are disposed to place a most singular volute, described with Mr. Broderip's usual accuracy, which partakes both of one and the other. It has, in fact, almost precisely the same elongated shape as a young specimen of fulminata, before the outer lip has been formed; while the number of its plaits are only two, thus agreeing with bullata. Divest the fulminata* of its outer lip, and it would have the same " fig-like" appearance as Mr. Broderip's H. dubia.^ That the plaits on the pillar of some of these shells increase with age, is proved by a young IT, vexillum, now before us, which has only four, instead of eight. (108.) In this manner, as it appears, the genus HABPULA forms a circular group, which, by commencing with H. fulminata, passes onward to Lapponica and vex- illum, and from thence to hebraa : polyzonata conducts us to costata ; and lyriformis to nucleus and bullata ; while dubia brings us again to fulminata. We may now compare the contents of this circle with the last. Analogies of the Genus HABPULA. Sub-generic Genera Sub-generic Types of Analogies. of the Types of HARPULA. VOLUTINJE. VOLUTA. H.fulminata. Lower plaits of the pillar small. SCAPHELLA. Magnifica. vexillum. Shells smooth. VOLUTA. Neptuni. f Shells muricated or nodulous; hebrtea. -\ apex obtuse, but not much J-CYMBIOLA. Imperialis. C enlarged. «— • PSSesT^eTva^0"8'] »«««• *** ilous; } nuch VI ower ? • i c • bullata. Plaits on the pillar very few. VOLUTILITHES. Angvlata. * I have recently «ome to a knowledge of the habitat of this shell, which is Java. •f- As Mr. Broderip's observations on this shell will be much more valu- able than my own, the reader will be better pleased by perusing that acute naturalist's own words. " This shell is one of those forms which convince us of the vanity of our artificial distinctions. When viewed from above, it seems as if the spire of a Valuta were placed on the body-whorl of one of those Pyrulce which are commonly known by the name of Figs. Turn it, and the difficulty of classing the shell is rather increased ; for the aperture is still fig-like, and it requires an accurate examination to detect the two almost imperceptible plaits on the columella. The apex, indeed, uncouth as it is, shows more like that of a Valuta than of any other shell, and it is utterly different from that of a Pyrula. Place it among, the volutes, and it will be found to approach nearest to V. rupestris; though one cannot but suspect that there are yet, in the bosom of the deep, many gradations of form between them. There is, I believe, one specimen in the cabinet of prince Massina."— Brod., in Zool. Journ. iii. p. 81. pi. 3. fig I. CHAP. IV. VOLUTILITHES TYPES OF FORM. 121 Of the resemblance between the three first, or ful- minata, SCAPHELLA, and magnified, we shall have to speak hereafter. The group which contains Harpula vexillum and Lapponica, as clearly represent the smooth melons, as hebraa does the bat volutes (Cymbiola*). There is a circumstance, also, regarding H. vexillum and Lapponica, apparently trivial, but of peculiar in- terest to those who delight in analogical researches: they are the types of the genus Harpula, which, as a whole, we have shown to correspond with the Strombidce ; and, in proof of this, we remarked that the major part presented the analogous character of the outer lip being carried upwards towards the spire. But this is not the only analogy : at the base of the outer lip, in fine and uninjured specimens of vexillum and Lapponica, is a slight but very distinct sinus*, rudimentary, as it were, of the distinct lobe in the genuine Strombi : this is not seen in the next division, represented by H. hebrcea ; but then, again, these latter shells have the top of the outer lip much more advanced on the spire. Costata not only represents, but is actually one of, the Harpulce ; while Volutilithes, with its few plaits, is equally repre- sented by bullata or nucleus. (109.) The types of form in VOLUTILITHES will now be inquired into. Throughout all the species we have seen, or which have been figured, the typical structure, in regard to the paucity of plaits and the acuteness of the spire, seems almost universal. The first group which unites these sharp-pointed volutes with H. lyriformis, seems to be such shells as V. costaria^, which, by a series of other species furnished with distinct convex ribs, like those of H. lyriformis, lead us, by means of muricina^., to musicalis and spinosa § (fig. 12. c, in p. 123.) : a third type is represented by the crenulata and bicorona \\ Lam. ; a fourth by his rarispina ; and the * This is precisely analogous to the corresponding prototypes, Rhinedo- nws and Cyllene. f Ency. Meth. pi. 383. fig. 9. j Ibid. pi. 38,3. fig. 1. a, and pi. 384. fig. 3. § Ibid. pi. 392. figs. 4, 5. || Ibid. pi. 384. figs. 5, 6. 122 SHELLS AND SHELL-FISH. PART I. fifth, which so singularly represents Voluta angulata and Cymbiola JSraziliensis (no less than the Pyrula), is seen in F. cithera*, this latter being the second type of the genus. (110.) That there exists mutual resemblances be- tween these presumed types, and those of the three preceding genera, will be evident from the following comparison : — Analogies of the Genus VOLUTILITHES. °r Wh°"y} Vexillum. VOLUTA. Crenulata. Shell entirely muricated. Hebr&a. CYMBIUM. f Spire much lengthened; (. enlarged. $ Cithera. Ventricose ; spire very short. Bullata. VOLUTILITHES. 1 Analogous to theStrombidce;~\ base, and often detached^ ?mrt^a' CAPHELLA. above. 3 Perhaps it may eventually turn out that the V. musi- calis || — a species we do not possess in perfection — is one of the typical forms, and that spinosa is the other : but the very singular-grooved suture of costaria and bicorona appears to indicate that a peculiarity of structure existed in the animal, of more importance than the mere form of the shell. The analogy, or rather the affinity, between costaria and the Harpulce must be apparent to every one, no less than that between Voluta angulata, Cymbiola Braziliensis, and Volutilithes cithera. Of * Ency. Meth. pi. 384. fig. 1. f It is not a little remarkable, that, in well-preserved specimens of the fossil species from France, the body-whorl is marked by transverse orange lines, completely analogous to H. vexillum. j If, as may be suspected, the Voluta labrella (Ency. Meth. pi. 384. fig. 3.) is the true type of this division, then its analogy to the smooth melons would be perfect, inasmuch as this fossil is entirely without the muricated spines of spinosa : I do not, however, feel at all satisfied that I have cor- rectly indicated this and the next type. \ As in the two species here compared. || Ency. M£th. pi. 392. fig. 4. CHAP. IV. SCAPHELLA TYPES OF FORM. 123 V. rarispina we can only form our conclusions from the figure in Ency. Meth. 384. fig. 2. It would seem from this, that there is a very distinct sinus at the hase of the outer lip, while the wide-spread deposition of enamel on the inner lip reminds us both of the genus Marginella and of Valuta Scapha : it is, in short, the strombiform type. (111.) We now come to the last genus, SCAPHELLA. Although these shells are readily distinguished by the experienced malacologist at the first glance, it is not so easy to define them by words. Their true characters, we apprehend, will be found in the animal. They differ from all other known volutes, by being always without sculpture, and generally polished like the Mar- ginellce. The apex of the spire varies precisely in the same way as in the genus Harpula : in the chief type, represented by S. undulata, it is small, and obtusely pointed. In fusiformis, it is decidedly thick; and in papillosa, it becomes exceedingly large and round. A shelly deposition is often formed in mature age, at that part of the outer lip which joins the spire, and also on the pillar side of the aperture : there is a con- stant propensity, in short, to this thickening of the pillar, even in shells which usually have their plaits distinct. The first advance to this structure, after leaving the last genus, is by a very singular fossil shell, described by Lamarck as the Buccinum strombitfides. ( fig. 12. a, b.) Mr. G. B. Sowerby, in adopting this name, justly observes, that, but for the absence of folds on the 124 SHELLS AND SHELL-FISH. PART I. pillar, its characters are more like those of a volute than a Strombus. One circumstance, however, not noticed by either of these writers, must be here mentioned : the whole shell is covered with a thin coat of shining enamel, as in some of the recent Scaphella, particularly thick at the top of the outer lip. This is always apparent ; while, in old ones, there is also a thick deposition on the upper part of the inner lip, which spreads over all the under side of the body- whorl. This, in fact, is but a slighter developement of that greater thickening of enamel seen in the last shell we spoke of, — namely, the Volutilithes rarispina ; and is precisely what might be expected in any type which was to connect it with the genus Scaphella. The absence of plaits on the pillar of this interesting shell (which for the present we shall call Scaphella strombo'ides) will not be at all incon- gruous, — because, in the whole of the Volutilithes, these appendages are small, and frequently almost evanescent ; while the detachment of the upper part of the outer lip from the spire plainly shows it is the strombiform type of this genus, as V. rarispina is of the last. (112.) Scaphella being thus connected to Volutilithes, we may pass over the two chief types, represented by S. undulata and fusiformis, and recall the reader's attention to the next in the series, — namely, Scaphella papillosa, formerly alluded to. Now, there are two other shells which more especially possess this kind of nipple-like apex, and in the same high developement, — the Harpula fulminata, and the Voluta fulgetrum : the question, therefore, is, to which of these is it mostly allied? On this point we reply, — to the latter by affinity, and to the former by analogy. It thus follows that we have traced the series of the volutes once more up to the typical genus, which we enter again by means of Voluta fulgetrum and magnifica. (113.) The four types of Scaphella, which are all we at present know, will thus find their respective ana- logies. CHAP. IV. SCAPHELLA TYPES OF FORM. 125 Analogies of the Genus SCAPHELLA. Types of SCAPHELLA. Analogical Characters. Types of VOLUTILITHES. Types of VOLUTA. Undulata. C" Shell very smooth ; suture > I enamelled ; spire small. 3 Crenidata. Cymbiola. Fusiformis. Sub-ventricose ; spire thick. Labrella ? Neptuni. Papillosa. C Tip of the spire thick and 7 i mammillary. J Costaria. Magntfica. ? ? Cithara. Angulata. f Inner lip thickened and gib-") e, J. "J Strombotdes. hous near the spire ; outer f lip angular and prominent f above. Rarisjrina. Scapha. (114.) This is the proper place for remarking a pe- culiarity in Volutilithes costaria, which we have not ob- served in its allies; the apex, although pointed, has one of the volutions thickened, — so that, in its own circle, it becomes exactly what papillosa is among the Sca- phelke. (115.) The peculiarly strong resemblance, however, between Scaphella papillosa and Harpula fulminata, is too remarkable to be termed a simple analogy. This brings us to another peculiarity of the natural system, of which full explanations and numerous proofs have been adduced in our former volumes.* The study of the different classes of the vertebrated animals, however, is quite out of the province of the malacologist, and we cannot suppose that he will assent to so novel a theory, unless it be proved in his own particular walk. We therefore lay before him, as a case in point, the aberrant groups of the Volutince, — namely, Harpula, Volutilithes, and Scaphella. The series in which we have placed these, commences with Harpula fulminata, and termi- nates with Scaphella papillosa. Is there not sufficient evidence that these two extremes meet? and that Sca- phella papillosa is as nearly related to H. fulminata as to Valuta fulgens ? If so, our series forms a circle. Thus, we find the whole family — as we began with assuming — constitutes one circular group, primarily * Geography and Classification of Animals, p. 226. 126 SHELLS AND SHELL-FISH. FART I. divided into three other circles, — the first of which, Foluta, is typical ; the second, Cymbiola, is sub-typical j and the third, which contains Harpula, Folutilithes, and Scaphella, constitutes the aberrant circle. This, in fact, is only in conformity with all other natural groups in the Fertebrata ; so that, if the principles upon which we have now arranged the Volutince are radically de- fective, so also are those in the innumerable groups that have been thus tested and verified in ornithology, ichthyology, &c. : for it is logically certain, that unity of plan cannot exist in the animal world, if one and the same principle of variation is not fundamental, and does not pervade all its parts. (116.) The MITRIN^E, or mitres, no less than the volutes, are characterised, in the great majority of the species, by very distinct and tangible characters ; but so soon as we reach the extreme limits of each, and look for those marks by which we have been accustomed to separate, with ease, the two groups, we find some of them gradually disappear, and others so modified and interchanged as to render it very difficult for an ordinary naturalist to draw any positive line of demarc- ation, — at kast, on those principles of absolute division insisted upon by some writers. It has, for instance, been thought that a shell having the spire papillary, and the lower plaits upon the pillar largest, was un- questionably a volute: and yet we have, in Folutilithes, a whole assemblage of shells whose apex is acute ; and in another group, Scaphella, the lower plait is always the smallest. Among the mitres, on the other hand, we shall find more than one with a papillary spire, and others where the lower plaits are as large as the upper. Hence it follows, that if no groups are to receive ge- neric or family names, but such as are distinctly sepa- rated, and are destitute of these intervening links, the old genera of Foluta and Mitra must again be united. Nor should we stop here: Mitrella so connects the mitres with the olives, that those, too, must be ab- sorbed in this gathering conchological snowball ; and CHAF. IV. THE MITRES GENERALLY. 127 with Oliva must follow Ancittaria : in this 'way we might go on until we have but one genus, Valuta. It is only by thus following out such a theory of nomencla- ture, that we see the full results to which it must, of necessity, lead. We have, indeed, already spoken on this subject ; but we think it desirable to place it more especially before our readers in this place, where the opposite plan has been so prominently brought forward. (117.) The whole of the MITRING, or Lamarckian mitres, were considered but as one genus until about twenty years ago, when we ventured to detach from them a small group by the name of Conoehelix. Nearly as great opposition was manifested to this innovation, as has recently been made in respect to Cyprcecassis , but this, of course, was to be expected from those conchologists who looked only for " well-marked and absolute divisions :" the group, however, was soon taken up by the Continental naturalists, and is now generally adopted. Having always had a peculiar fondness — almost a passion — for these elegant shells, we continued their study, until, in 1827, our investigations had pro- ceeded so far that we ventured to characterise the five leading divisions, or genera. The great number of new species discovered by Mr. Cummin, added to others con- tinually coming before us, naturally led to a still more close analysis of the whole. The result of this, in re- gard to the theory of variation, was communicated to the Zoological Society in 1835.* This theory is now found to pervade the whole class of Testacea ; while, in our Systematic Arrangement, will be found all the well- known and clearly described species, distributed under their several minor groups. The Mitrince, in comparison to the volutes, with two or three exceptions, are much smaller shells, chiefly distinguished by the smaller size of the foot, as in Mitra episcopalis (fig. 13.), where the proboscis is excessively long ; and by the greater length of their spire, the tip of which is never papillary, t The * Proceedings of the Zool. Society, part iii. p. 197. t Except in two or three species of Mitreola, which blend into Harpula. 128 SHELLS AND SHELL-FISH. PART 1. upper plaits of the pillar, in almost all, are larger than the lower; and the general form of the shell is equally or unequally fusiform. It is almost impossible to esti- mate the number of species, as new ones are constantly coming to light ; but there probably exists already, in our cabinets, about two hundred and fifty,, of which more than forty were brought home by Mr. Cummin from the western coast of Tropical America. We suspect., from these data, that, in a few years, the increase of known species will come near to 300, leaving out those that belong to the three aberrant genera — Mitrella, Conc&helioc, and Mitreola. Nearly all these are excluded from the European seas ; and, what is still more extra- ordinary, not more than half a dozen can be called com- mon shells. This scarcity of mitres certainly does not originate from the difficulty of gaining access to their haunts ; for, although some are known to live at great depths *, yet both MM. Stuchbury and Cummin inform us that they generally found these shell-fish in shallow water, near coral reefs. Hence we conjecture that their chief metropolis must be the great Pacific Ocean, where, among the countless numbers of existing islands, and the coral foundations of others, the number of species now unknown may be nearly equal to those already described. The animals of a very few have been pub- lished by M. Quoy, in the invaluable plates of his voyage ; for the particulars of which we have not suffi- cient space. (118.) The primary divisions of the whole of the family, as already intimated, correspond with those of * As Mitra zonata, which, Dr. Leach says, was fished up out of very deep water near Nice. CHAP. IV. DIVISIONS OF THE MITRES. 129 genera of the volutes ; and they may be thus briefly characterised from their V shells. The most typi- cal is — 1 . Mitra, where the basal whorl is some- what ventricose, and the aperture has no inter- nal groove. 2. Tiara (fig. 14.),, having the basal whorl contracted, and the internal groove distinct; — this is the sub-typical genus. The 3d, or next, Mitrella, resembles the olives in being smooth, and in having the base of the pillar thickened, with the plaits very much projecting. In the 4th, or Concehelix, the spire is very short, the plaits numerous, and sometimes indistinct: whereas, in the 5th, or Mitreola, the upper plaits are smallest, the outer lip inflected and sometimes toothed, and the spire slightly papillary. As all these peculiarities will be detailed in the next division of our volume, we shall here only make a few general observations on the contents of the genera ; and first, with regard to The Analogies of the VOLUTIN^E and the MITRING. Genera of the Mitrince. MITRA. TIARA. MITREOLA. CON02HELIX. MITRELLA. Analogical Characters. T Body- whorl never contracted at < the base ; the whorls never tur- C retedor angulated. fShell turreted; body-whorl con-") | tracted in the middle; the) •4 whorls nodulous or sub-coro- ^ J nated, or carinated, rarely | L smooth . J rThe upper plaits on the pillar < smaller than those in the mid- C die ; spire sometimes papillary. re very short ; plaits very slen- der, sometimes obsolete ; sur- face generally reticulated or striated, r Smooth, generally polished; the} < lower plaits smaller than the > (. upper. J I. UU ( Spirt ) dei j fac ( str Genera of the Volutince. VOLUTA. CYMBIOLA. HARPULA. VOLUTILITHES. SCAPHELLA. 130 SHELLS AND SHELL-FISH. We shall make no other commentary upon this table,, than as regards the rank of the groups in each column, which are thus shown to be genera. The sub-genera, of the Volutince, it will be remembered, we have indi- cated, but not named, because the species they contain are so few, and these so well known, that it might be thought a needless multiplication of names. But in the present family the case is widely different : as not one third of the mitres are figured, and the descriptions of most of the remainder are too vague to admit of deter- mination, it becomes absolutely necessary, not only to characterise, but to name, the sub-genera. This we have accordingly done, — confining ourselves, however, to the two typical genera, which, as in all such groups, con- tain the great majority of the species. The foregoing table shows that Mitra and Tiara are the two groups in question; and, as the definitions of their sub-genera will be hereafter detailed, we shall at once lay before the reader the exposition of their analogies. Analogies of the Genera MITRA and TIARA. Sub-genera of Mitra. Internal canal wanting; aper- ture smooth. Mitra. Tiarella. Scdbricola. Nebularia. Strigatella. Analogical Characters. r Spire and aperture of equallength, } -< unequally fusiform ; body- S- C. whorl obtuse. J f Shell with distinctly coronated, 7 I acute, or obtuse tubercles. j C Shell with numerous elevatedribs, } < longitudinal in one, transverse > C in the other. .) ("Shell reticulated or cancellated ; 7 I the base of the aperture effuse. J f Size very small ; outer lip thick- < ened, and generally gibbous t within. Sub-genera of Thiara. With an internal canal ; aperture striated. Costellaria. Tiara. Callithea. Cancilla. Pusia. It thus appears that each of the divisions, or sub- genera, of Mitra finds its representative in Tiara; and that, without a due regard to the essential characters which distinguish these two genera, it will be impossible CHAF. IV. SUB-GENERA OF MITRA AND TIARA. 131 to know to which of them a Lamarckian Mitra really belongs. We are sorry, indeed, to impose so much trou- ble upon collectors; but the blame,, if any, must be laid upon Nature — not us : for we merely endeavour to trace her steps. But she does not stop here. Into each of these sub-genera, which happen to be full of species, she actually carries the same principles of variation ; so that, if all the shells really belonging to our sub-genus Mitra, even as now restricted, were spread before the naturalist, he would find not very incipient characters of every one of the sub-genera just enumerated ; and this, to such an extent as to justify our reaching this conclusion, — that if the whole of the species that have been created were known, every Mitra would have its counterpart, or prototype, in the circle of Tiara. Any naturalist may convince himself of this, by look- ing to the five sectional types of the sub-genus Mitra, for instance, as episcopalis, rujfina, punctata, lactea, and sonata. The second represents Tiarella by its crenated suture ; the third shows us the roughness of Scabricola ; the fourth the effuse aperture of Nebularia; and the fifth the dingy colour and thick epidermis of Strigatella. The Mitra terebralts and the Tiara terebralis* are counterparts of each other, and are only prototypes, under a different form, of the genera Terebra and Tur- ritella. We regret exceedingly that we cannot give as full an exposition of the mitres as we have done of the volutes : half a volume would hardly be sufficient. It seemed preferable fully to detail our analysis of the first, as being the typical group ; and because, from the comparative paucity of the species, the natural series be- came more difficult to demonstrate than that of the mitres. Now, as the principle of variation in each is precisely the same., we have given only the results of * Of this shell, Mr. Broderip justly observes, " It is one of the most slen- der of its genus, and has very much the general character and form of a Terebra : this resemblance is increased by the circumstance of its having one spiral groove more deeply impressed than the others, placed at about one third of the length of each volution before the suture." — Proc. ZooL Soc. part iii. 1835, p. 196. K 2 132 SHELLS AND SHELL-FISH. our investigation in the mitres. Whether we view the family Volutida as a whole, or contemplate separately each of its divisions, whether large or small, we shall find their variation uniformly harmonising with what has been seen in the Muricidce and the Turbinellidce, — a fact which every one will perceive, on investigating the following table, which is also sufficient to furnish the clue even to the analogies of the sub-genera. General Analogies of the VOLUTID^. Families of the ZOOPHAGA. Sub-families of the Volutidce. Genera of the Volutiiue. Genera of the Mitring. Sub-families of the Muricidce. Sub-families of the TurbinellidcE. TURBINBLLID.* MURICIDJE. VOLUTID.«. I. V,OLUTIN.aS. MlTRINjE. ANCILLARIN.E. Voluta. Cymbiola. Harpula. Volutilithes. Mitra. Tiara. Mitreola. Concehelix. CASSINJE. MlJRIClNjE. BuCCININjE. PURPURIlVjE. TURBINELLINjK SCOLYMIN.E. Fusm^E. PYRULINJE. STROMBID*. MARGINELLTN^E. Scaphclla. Mitrella. NASSINJL. EBURNIN.E. (119.) The three aberrant divisions of the volutes, namely, the OLIVIN^E, the ANCILLARIN^E, and the MAR- GELLINJE, must be dismissed in a few words. The minor variations in each are very few, and will be found in the systematic arrangement. The genus Mitrella leads us immediately from the mitres to the olives ; where, as in Harpula, the plaits upon the pillar cover the whole length of the inner lip : the foot of the animal is ex- cessively large, and sufficiently dilated to fold over the greater part of the shell ; but the mantle is not lobed. The first genus is Lamprodoma *, which chiefly differs from Mitrella in having the channeled suture so uni- versal among the olives. This leads to the typical genus Oliva., wherein the majority of the species are still arranged. Scaphula, by its thick undefined spire and ventricose body-whorl, is a complete prototype of the melon volutes, and prepares us for Hiatula, in which the characters of Oliva, Scaphula, and Ancillaria are com- bined. The circle is then closed by those small species arranged under the genus Olivella, wherein the base of * Lamp. Olivella, Zool. 111. ii. pi. 40. fig. 1. CHAP. IV. ANCmLARIA. MABGINELLA. 133 the aperture is only effuse, and the spire as much length- ened,, as inLamprodoma: the plaits on the pillar, like those on Volutilithes, are reduced to their minimum; the two last are the strongest, the others nearly obsolete. It is by this particular group that the VOLUTID^ and the TURBINELLID.E are united ; the direct passage being marked by Olivella biplicata Sw. in one, and Pseudoliva plumbea Sw. in the other, (fig. 3. at p. 82.) The olives are among the best known, the most polished, and the most variable shells in this family. They swarm in the seas of tropical climates, more especially in the East, but seem altogether excluded from the European coasts. (120.) The forms, or variations, among the ANCIL- LARIN.E are as yet too few to render it necessary to create sub-divisions : the beautiful analogy which this group bears to the Purpurince, by the prominent little tooth on the outer lip, as well as by the width of its aperture, must not be overlooked ; while the high polish of all the species, the general shortness of the spire, and the unusual thickness of the base of the inner lip, are so many points of resemblance to the Cyprceidce. (121.) Finally, the MARGINELLID^E are the smallest shells, as to size, in the whole family : they are at once distinguished by their thickened outer lip ; but they all vary in the absence or developement of the spire and of the inner lip, as well as in the plaits of the pillar : hence their genera may be sufficiently defined. Their union with the Volutince, by means of Scaphella Zebra*, is clearly shown by our genus Glabella, where the inner lip is either entirely wanting or but slightly developed : these latter conduct to Volutella, which, by its obsolete spire, preserves a strong analogy to the melons. In Persicola we have a prototype of Concehelix; while the typical form, Marginella, has the inner lip so much developed, as to form a thickened deposition all round the aperture. On the fifth type we feel some uncer- * Placed among the MarginelUe by Lamarck. K 3 134 SHELLS AND SHELL-FISH. PART I. tainty ; but we think it is represented by those species which have the outer lip gibbous above, analogous to Valuta Scapha and other strombiform types ; or it may possibly be Lamarck's fossil genus Volvaria. It is easy to perceive, however, how strikingly this sub-family, as a whole, represents the Nassince, the Eburnince, and the Columbellince, all which are prototypes of the Strombidce. (122.) We shall conclude our exposition of this interesting family by what may be called a continu- ation of the last diagram, for the purpose of illustrating certain analogies in regard to the animals. Analogies of the VOLUTID;E to Fertebrated and Annulose Animals. Genera Sub-families Families Tribesofthe Classes of Classes of *«. PMtoka.a. Valuta. Cassin&i Trochida. AfRACHiA. MAMMALIA. APTERA. Cymbiola. Muricince. Helicidee. MACROTRACHIA. AVES. PTILOTA. Harpula. Buccinince. TurbicUe. TUBULIBRANCHIA. REPTILIA. ANNELIDES. Volutilithes. Purpurirus. Naticidce. CHELISOMA. AMPHIBIA. VERMES. Scaphella. Nassince. Haltotidte. BRANCHIOPODA. PISCES. CIRRIPEDES. It is chiefly with reference to the fifth set of types, which contains the longest-bodied animals in all these circles, that we have drawn up this table. A pecu- liarity is of course shown in the Testacea, by the pro- longation of the spiral whorls : hence we find the longest-spired volutes are in the genus Harpula. The Buccinince contains Terebra ; and the genus Turritella is the type of the Turbidce. Continuing this analogy on to the bivalves (Dithyra}, we have the long tubular snake-like shells of the Tubulibranchia, representing the real serpents among vertebrated animals, and the Annelides among the annulose or insect tribes. The excessive developement of the organs of locomotion, or foot, as shown in the first set of analogies, is most re- markable. But as a chapter would be insufficient to illustrate the innumerable analogies concentrated in this CHAP. IV. CYPR^ID^ OR COWRIES. 135 table, we must leave it, as a fruitful an,d untrodden field to those who wish to prosecute its .study. (123.) The passage to the CYPR^ID^E is so well marked by those MarginellincB which have the spire com- pletely hidden, as to leave no doubt of the cowries follow- ing the volutes. We must, for want of space, omit the accounts of the animals of the two typical divisions, Cyprcea and Ovula, now well known by the excellent descriptions of MM. Quoy and Gaimard : suffice it to observe, they have some things in common with the volutes; — the foot is very large, and the tentacula short : the mantle is dilated into two large lobes, almost sufficient to cover the shell entirely, — their junction being marked by a pale line down the back, where the colour often appears as if faded. The Cyprceince, or cowries, form the typical, and the Ovulince, or egg-shells, the sub- typical, group. The former are well known as among the most -elegant and richly coloured of the Testacea; always having the spire concealed, and generally onisci- fonn, — that is, oval, and flattened beneath. The species are particularly numerous in tropical latitudes, and several are among the most common shells in our collections: they have been very ably investigated by Mr. Gray, who has judiciously characterised and named some of the types ; for they were all left by Lamarck in one genus. The Ovulints resemble in general form the cow- ries ; but the extremities of the aperture are generally produced, and there are no teeth on the inner lip. Not having yet investigated this division, we shall for the present leave it as it is, and merely notice those which seem to be the aberrant genera, connecting this family, on one side, to the Folutidce, and, on the other, to the Strombidce. The first we conjecture to be the fossil genus Volvaria, as well defined by Mr. Sowerby * ; while the latter union appears to be affected by Erato, where the general shape is that of a Columbella, but with the dorsal sulcated line of Trivea : between this we are dis- posed to place, under the name of Cylindrella, two or three * Genera of Shells. K 4 136 SHELLS AND SHELL-FISH. small shells resembling Folvaria in form, but destitute of any plaits upon the inner lip. The Cyprceidte will thus form a group far less perfect in its contents than the Volutida, yet sufficiently marked to constitute it circular. CHAP. V. THE PREDACEOUS GASTROPODS CONTINUED. THE STROMBID^E, OR WING-SHELLS. (124.) THE STROMBID,E is one of the most varied of the predaceous families, not so much in the structure of the animals, as in their shells. The typical group, indeed, is very peculiar in both respects ; but the animals of the rest, with which we are as yet acquainted, have a much greater sameness than would have been expected from the marked difference in their habitations. In regard to the first, the most prevalent character appears to be the pedunculated nature of the eyes, which are generally situated about midway upon the tentacula — never at their base, or at their tips. In the typical StrontU, these organs are so much de- veloped, that the iris is richly coloured; and the eyes of some of the large species have been described to us as particularly beautiful. The shells present every variety of the spiral form, excepting that they are never depressed ; yet, throughout the whole, one character may be traced : the outer lip is either enlarged, thick- ened, or expanded ; or, if not so, the upper part is detached from the spiral whorl, so as to form a wing- like or angular projection ; hence their common name of wing-shells : all are furnished with a small operculum, and are strictly external shells. In the Lamarckian genera Strombus, Conus, Columbella, Pleurotoma, and Cerithium, the student will see the five principal types. CHAP. v. STBOMBID.S:. 137 (125.) The rank of the group being that of a family, its first divisions, just mentioned, become sub-families. 1. The Strombina, or true wing. shells, having the outer lip greatly dilated, with a lobe at the base, and often on the summit also, of the outer lip ; the spire being always more or less elevated. 2. The Conince, or Cones, where the spire is so depressed as to be turbinated, and scarcely raised above the body- whorl : the aperture is always smooth; the outer lip without any lobe, and only slightly detached above. 3. The Columbellma, or dove- shells, small in size, and with short-pointed spires ; the outer lip is thick, turned inwards, more or less toothed on its edge, and gibbous above ; there are also tuberculated teeth at the base of the inner lip, but no regular plaits. 4. The PhurotomintB, or slit-shells, — so called from a deep lobe, or slit, at the top of the outer lip : the spire, in general, is very long, and the shells themselves often spindle-shaped. 5. The Ceri- thinte, called club-shells, from their clavate form : the body- whorl is not much larger than the one which precedes it ; but the outer lip is slightly detached above, and then much dilated ; the basal canal, which is always very short, is generally more or less turned backwards, (126.) These primary divisions appear to form a circular series, and to be united in the following man- ner : — Commencing with the Strombin&, we pass from them to the Cerithince, ' by means of that well-known shell the S. pes-pelicani of Linnaeus, which, in its im- mature state, before its lip has expanded, might easily be mistaken for a young Cerithium. Next to these latter, Lamarck places the Pleurotomince ; their junc- tion being formed by his Clavatula, and the genus Potomis : with these, again, a union is rendered abso- lutely perfect with the Columbines, by means of certain genera now denned for the first time : others of the Columbince so strikingly resemble small cones, that but for a close inspection, they could not be distinguished. From the cones we pass to the singular genus Terebellum, 138 SHELLS AND SHELL-FISH. PART I. which brings us once more to the Strombina ; and ter- minates the series. We shall now take each of these sub-families in succession, and lay before the reader the result of the closest analysis we have been able to give them. (127.) The STBOMBIN^E, or true wing-shells, are obvi- ously the pre-eminent typical group ; and consequently stand at the head of the family. The great expansion of the outer lip in all the genera, save one (Strombidea*),, which connects them to Terebellum, is their best, and, indeed, their only general, distinction. The genera are five : Strombus, Strombidea, Rostellaria, Aporrhais, and Pterocera; all of which are easily recognised. The most typical, perhaps, is Pterocera, where the outer lip is expanded, in mature age, into very long claw-like processes, which gives them something the appearance of scorpions, with the legs, on one side, stretched out, and those of the other concealed ; but their chief cha- racters seem to rest on the basal lobe of the outer Up being turned inwards, and generally toothed. This character, hitherto overlooked, has caused two of the sub-generic types to be placed with the Lamarckian Strombi ; and hence the latter has been overburdened with shells which, we think, do not naturally belong to it. The first, or typical, form is seen in P. lambis, where the processes of the lip are all pointed in one direction ; and the basal canal, which is considerably lengthened, is curved only on its terminal half. The second is the P. millipeda, — differing from the last, not only in the greater number of the processes, but in those adjoining the spire being more united together at their base ; or, in other words, the divisions are not so deeply cleft. This type prepares us for the third, which has all the characters of Pterocera, except that the lateral pro- cesses are wanting, and the upper are only indicated by deep lobes : the only example yet known, is the shell we formerly figured under the name of Strombus sinu- * Represented by Sir. urceus and its allies. CHAP. V. PTEROCERA. STROMBUS. atus, but which we now remove to the present genus. This we also do with the Strombus latissimus of authors, which constitutes our fourth type. This remarkable shell immediately follows the Pterocera sinuata ; and although the digitations no longer appear, they are slightly indicated by little folds : the side of the outer lip, as in all the other types, is broadly reflected inwards. In the fifth and last form, as seen in P. chiragra, the digitations are again developed ; but they are fewer in number, and of nearly equal length. In this type, also, the basal channel is recurved outward ; and the sinus on the lip is so remote from the base, as to admit of an intervening process. (128.) The restricted genus Strombus follows that of Pterocera ; it is distinguished by the outer lip being entire, much dilated, and always furnished with sinu- osities, or lobes, both above and below : the base is short, and slightly turned upwards. In this genus there are five distinct modifications. The Pterocera sinuata leads us immediately to the first type, which is com- posed of S.melanostomus, pacificus, Auris-DiantB Linn., and Lamarckii.* In all these, we trace the last rem- nant of the character of Pterocera, — namely, the folding back of the outer lip, which is particularly conspicuous in our S. melanostomus and Pacificus : the upper part, also, is prolonged into a lengthened process. As a group, it is at once known by the basal canal being turned back, as in the Ceriihina, or rabbit-shells. From these, by means of S. tricornis and Gallus, we are brought to the beautiful pink-mouthed S. gigas, and the rare S. Goliathus, where the lip may be said to have attained its maximum. In Accipiter and Canarum, it assumes the shorter and more wing-like form of the type which succeeds this : all these, with Strombus granulatus, &c., and, finally, Epidromus, seem, to us, to constitute a second type of form, wherein the outer lip is particularly large and spreading, yet without that short sinus, or * I know not who has affixed this name to what was considered the smooth variety of Auris-Diance . 140 SHELLS AND SHELL-FISH. PART 1. lobe, which is so prevalent in the next group. This lobe is most conspicuous in S. lentiginosus, where, in fact, there are two ; as is the case, also, in our S. GaUu(> and tuberculaius ; but in minimus, variabilis, &c., the lobe is less apparent. Yet, in all these, the outer lip, although large, is not reflected, but takes a curve in- wards. The fourth type is seen in S. gibberulus, which is remarkable for the shortness and distortion of the spiral whorls, and the very slight expansion of the outer lip : it is chiefly remarkable, however, for a thickened deposition of enamel at the top of the inner lip, analo- gous to that in Nassa, Oliva, &c. These are connected to the last by Luhuanus, which has the distorted spire, but not the other characters, of gibberulus. The fifth and last type is seen in the Strombus succinctus, remarkable for the prolongation of the lip, very high upon the spire, so that it becomes a perfect represent- ation, in this group, of Rostellaria. (129.) The next genus is Strombidea, — a name we give to all those small shells, which, like S. urceus and its congeners, have the outer lip merely lobed at the base, without being detached, or dilated above. We take some blame to ourselves, for not having long ago perceived that these shells were not true Strombi ; but we had then only analysed the family in part ; and, as usual in such cases, we subsequently found that we were in error.* The Strombidea, in short, are proto- types of the Columbettince ; and so strong is this analogy, that our S. crassilabis was sent to us as a Columbella. (130.) The genus Rostellaria contains some few of the most elegant and costly, if not the most beautiful, shells in this family : it is, therefore, very interesting, even to the conchologist ; but it is particularly so with reference to its types. The primary distinction of all these shells, — few in number, but singularly varied, — is a slender channel, thickened on each side, which * I allude to the article regarding the Strombida in the second series of the Zoological Illustrations. CHAP. V. ROSTELLARIA. APORBHAIS. 141 ascends from the aperture nearly to the top of the spire : the shell has much of the shape of a typical Pleurotoma; the basal channel being more or less lengthened. To this genus we are led by the Strombidea tridentata, — the only Strombus which gives us at once the outer lip of Ros- tellaria curvirostris, with all the other characters of our genus Strombidea, The first type of Rostellaria is seen in those elegant shells, R. curvirostris and rectirostris, where the siphon is moderate : the outer lip is hardly dilated,, since its margin is merely divided into short processes. The rectirostris is of great rarity ; but of still greater value is that which forms the second type ; indeed, it seems to be known only by the figure of Chem- nitz, and has been altogether omitted by Lamarck : it is channeled to the tip of the spire ; while the outer lip, without being much dilated, is divided into a number of short spine-like processes. In the third type, Ros- tellaria macroptera, the upper siphon is equally long ; but the lip, instead of being cleft, is entire, semicircular, and dilated to an enormous size. In these two last types, in fact, we have the greatest developement of the lip; and hence we may expect a declension in the succeeding forms. Such is accordingly seen in Rostellaria columbata., where the lip, although dilated and very broad, does not extend more than half way up the spire, although it is rather lengthened into the same sort of lobe as that in Strombus pacificus. There is still a great difference between R. columbata and the first type we noticed ; but our fifth brings them together : this is formed of the small species, four or five in number, among which the elegant little Grignon fossil, Rostellaria fissurella Lam., is the best known. In these shells, the lip is no longer dilated, nor is it extended up the spire ; they lose, in short, one half of the characters of their own genus, and in the same pro- portion assume those of Strombus, — thus becoming the most aberrant type of the sub-family; while their station between R. curvirostris and columbata is apparent to the most unscientific eye. (131.) The last genus is that of Da Costa's Apor- 14,2 SHELLS AND SHELL-FISH. rhais, and the only example yet known is the pes-peli- cani, or pelican's-foot strombus. That it has a close affinity to Rostellaria columbata is evident from the outer lip being dilated ; but then it has four lobes,, or rather flattened and digitated processes, something similar to Pteroceras chiragra ; and it deserves attention, that these are the only two in the family which have the basal channel assuming precisely the form, size, and structure of the other processes of the outer lip : on the other hand, it has no distinct lobe at the base, its mar- gin is not inflected, and the upper part advances upon the first spiral whorls ; — in all which it shows an affinity to Rostellaria. In its young state, however, (fig. 15. a) it has quite a different appear- ance ; for its form is then so much like that of a young Cerithium (b), that none but a scientific observer could detect the difference. Equally related in this man- ner to three different ge- nera, we look upon this type as connected to Ros- tellaria on one side, Pte- rocera on another, and to the Cerithince on a third. All these affinities are more peculiarly apparent in its three different stages of growth; so that, when quite young, it is a Cerithium ; when the outer lip is half expanded, it is a Rostellaria ; and, in adult age. it puts on the very aspect of a Pterocera. Here we close our evidence on the affinities and natural arrangement of this family. (132.) Having now gone through the affinities, we turn to the analogies of the Strombince. They are ob- viously the typical division of the whole family; and, as such, should represent within their own circle all the. other divisions : this will be apparent in the following table :-r- CHAP. V. ANALOGIES OF THE STROMBIN^. 143 Analogies of the Genera of the STROMBIN^;. Genera of STROMBIN.E. Pterocera. Strombus. Strombidea. Host ell aria. Aporrhais. Analogies. Sub-families of the STROMBlDjE. Outer lip greatly dilated, andlobed. STROMBIN^E. ("Outer lip detached above, and en- 7 m*,, i tire. 5 C Outer lip not detached, but gib- } < bous ; both lips thickened, and > COLUMBELLINJE. C. generally striated. J Shell long, slender, fusiform. PLEUROTOMIN.E. C Shell club-shaped when young ;~) < the channel very short, and > CERITHIK£. I. twisted on one side. J These variations take place in precisely the same or- der as that in which the relations of affinity occur j for each of these columns is a circular group,, — the genus Aporrhais being as much connected to Pterocera as to Rostellaria. Turning to the other group, we perceive the very same affinity between Cerithium and Strombus, through the medium of Aporrhais, as between Cerithium and Pleurotoma. The resemblance between Strombidea and the typical Columbellince , again, cannot be mistaken ; for the outer lip of both forms a sort of angle or gib- bosity, altogether peculiar to these two groups. This remarkable thickening, in short,, of the lips in Strombidea, renders the genus a prototype of the Columbellince, as well as of the Mar- *** l*m ginellince. Rostella- ria and the Pleuro- tomince are the only fusiform groups in the whole family ; while the likeness of a young Apor- rhais to the Ceri- thince need not be dwelt upon. The resemblance between such shells as Strombus Luhuanus (fig. 16. a), when young (b\ and Conus amadis (c), and others, is so great, that an unpractised eye can hardly tell the difference. 144 SHELLS AND SHELL-FISH. PART I. (133.) Our next comparison will be between the types of form in the genus Pterocera, and the genera of the Strombince. Analogy of the Types of Form in the Genus PTEROCERA. Types of PTEROCERA. Lambis. Millipeda. Sinuata. Latissimus. Chiragra. Analogies. Basal canal greatly lengthened. Basal canal short. TOuter lip thickened, and inflected 7 t inwards ; basal canal truncate. J C Outer lip extending to the apex 7 i of the spire, and entire. J r Canal resembling the digitated ") •J processes of the lip, and turned > C on one side. j Genera of STROMBIN.E. PTEROCERA. STROMBUS. STROMBIDEA. ROSTELLARIA. APORRHAIS. In such small groups as these, we cannot expect the analogies to be very strong; a faint resemblance is all that exists — and all, indeed, that is necessary. Yet it is remarkable how perfectly P. latissimus corresponds to the Rostellaria macroptera in its excessively large outer lip, which, in both shells, runs up to the top, and even spreads far beyond the apex of the spire. (134.) The analogies of the genus S trombus are nume- rous, and, in some measure, too complicated to be here introduced : it will be sufficient to remark, that, besides the five leading divisions or types of form, there may be discerned indications of another set of secondary types ; so, that, if such groups were better understood (as no doubt they will be hereafter), some of them may be found to contain representations of the primary genera of the StromUnce, no less than of its leading divisions. The time, however, is not yet come for such an elaborate study of analogies as this implies ; and we shall, there- fore, merely place before our readers the five divisions of the genus, which, as already specified, seem to be represented by the five following shells : — Strombus Auris-Diana, gigas, lentiginosus, gibberulus, and suc- cinctus. All these are among the most common species, CHAP. V. CONINE, OR CONES. 145 and, as such, may be readily procured by every student who feels interested in these inquiries. Analogies of Types of the Genus STROMBUS. Species of Strombus. A j • , Divisions of the Analogies. Strombin*. S. Auris-Dian&. f Channel bent ; inner lip spread- 7 \ ing on the spire. J APORRHAIS. gt'gas. Outer lip reflected, entire. STROMBUS. lentiginosus. 5 Outer lip inflected, divided above; 7 i basal lobe toothed. 3 PTEROCERA. gibberulus. ("Outer lip slightly or not at ain i expanded. J STROMBIDEA. succinctus- CA long siphon running up the 7 i spire. J ROSTELLARIA. By arranging the intermediate species between each of these types, the whole would exhibit another set of relations, as well as a series of connecting links ; thus Auris-DiancB is followed by a little group composed of tricornis, gallus, and Peruvianus, which connect the for- mer shell with S. gigas : but the student, after these hints, will find no great difficulty in following up the theory himself. (135.) The next genus, Rostellaria, is particularly interesting to the lover of analogies, inasmuch as all the types are not only existing, but are of that definite character which leaves no doubt of their true import. Species of Hostel/aria. Serrata Sw.* Macroptera. Columbata. Rectirostris. Fisturella. Analogies of the ROSTELLARI^E. Analogies. r Outer lip reaching to the tip off < the spire, and divided into pro- > C cesses. 3 Outer lip very large, and entire. ("Outer lip hardly attached to the 7 i spire, and dilated into a lobe. 3 C Outer lip not dilated at the top, ) 1 and not extending on the spire. 3 ("Outer lip hardly dilated, but the") *c J siphon ascending to the apex I J of the spire ; the margin with-f Genera of Strombintr. PTEROCERA. STROMBUS. APORRHAIS. STROMBIDEA. ROSTELLARIA. * out teeth-like processes. Figured in Chemnitz, pi. 195 A. fig. 1869. L 14)6 SHELLS AND SHELL- FISH. PART I. It thus appears that each type of the Rostellaria;, as arranged according to their affinities, turns out to be a representation of one of the genera of the StrombintB : and these analogies are so perfect, that it appears to us absolutely impossible they could be more complete — at least, in regard to the shells ; although they would be even more beautiful, when accompanied by a corre- sponding relation in the animals. R. rectirostris is the fourth type, and not the common curvirostris ; because this latter is intermediate in structure between the former and R. fissurella. (136.) We feel persuaded, that if the concluding volumes of the elaborate work of Lamarck had not been finished "under the eyes of another," because their celebrated author had become blind, we never should have seen our Rostellaria cancellata and canalis placed in his genus Strombus. No species, in fact, either of Strombus or of Pterocera, so far as we know, occur in a fossil state. It appears hardly necessary, in so limited a group, to impose sub-generic names of these types ; for if one is named, all should be so. Such designations are not necessary to facilitate research, when the whole genus contains not more than, perhaps, a dozen species. With the mitres, the cones, and the land snails, &c., the case is very different : such groups contain hundreds of species ; and by designating their sub-genera under patronymic names, most material help is afforded, in all ways, to minute research, or to general views. (137«) The connection of the CONESUE, or cones, with the Strombince, is effected by- our new genus Strombidea in the latter, and Terebellum in the former. The affini- ties of these two genera we pointed out many years ago, by the publication of a shell which actually unites the characters of both *; and Lamarck entertains no doubt of the close connection of Terebellum to Conus. Tere- bellum, in short, merely represents the olives in this circle, without having any real affinity with them ; but * Strombus dubius. See Taylor's Phil. Mag. 61. No. 301. May, 1823. This will now be our Slrombldea dubia. Specimens are in the rich collection •f Mr. Stanford. CHAP. V. CONINE, OB CONES. 14? 16 of their animals, nothing, we believe, is yet known. The true cones, from their beauty, are the favourite shells of conchologists. Nearly all are natives of tro- pical climates, where they constitute one of the most extensive races of the carnivorous shell-fish. The mouth is a short proboscis (fig. 16. a), which in one genus (Coronaxis Sw.) has the margin simply cir- cular, while in the other (Conus Linn.) it is laciniated, or divided in to a circular fringe of little points, analogous to the lips of the Trochi- dce. In both these genera, the ten- tacula (&) are short, cylindrical, and nearly obtuse, with the eyes small, and but slightly developed, placed half way on their external side : the foot is small, rather broad, trun- cate in front, and rounded behind, where it bears a small oblong oper- culum, sufficient only to close the detached part of the top of the outer lip. The respiratory siphon (c) is well developed, but its form seems to vary in the sub -genera : in some, it is thickest at the base (as in C. bandanus*} ; in others (C. arenatus), it is uniformly cylindrical. t Lamarck describes no less than 181 species, besides nine fossil; but we question if there are not more than 230, or perhaps 250, species already in collections. Such an immense assemblage of mere species, as they now stand, fully justifies us in giving patronymic names to the sub-genera, and arranging them in distinct groups; a plan long ago recommended J, but never yet acted upon. By separating the coronated from the smooth species, nothing material is gained ; for although they constitute, in reality, two genera, the internal relations subsisting between them are passed over ; and these, in our opinion, * Voy. d' Astrolabe, pi. 52. fig. 7., here copied ./fc. 16. t Ibid. pi. 52. fig. 8. I Sow. Genera of Shells, article Conus. L 2 148 SHELLS AND SHELL-FISH. PART I. are the most important object to be illustrated ; while the mere collector has no additional help to the no- menclature of the species, more than he now has. Long and procrastinated attention to these beautiful shells, together with the invaluable delineations of their animals by M. Quoy, has now enabled us to give the following exposition of the genera and sub-genera.* Analogies and Characters of the Sub-genera of CONUS and COBONAXIS. CONUS. CORONAXIS. Shell not coronated. Shell coronated. C. litteratus. f Shell ponderous ; basal whorl not ) Dan/f ,,„,,, virgo. < contracted near the suture; S^""^"* generales. (. spire in general flattened. 3 striatus. f Shell ponderous ; basal whorl con- T Arenatus stercus-muscarum. < traded near the suture; spire > , n. ammeralis. C short, pointed. 3 ced°-nuUl- C Shell light ; basal whorl ventri- ~\ j cose ; aperture effuse ; the base ( ^ , . I hardly notched; spire short, ( lui'Pa- C pointed, concave. J bullata. ( Shell light ; basal whorl ventri- textile. auratus. aulicus. (. pointed, concave nussatella. C Shell sub-conic, cylindrical, trans- ^ glans. < versely grooved ; spire elevated, > . terebra. C thick, convex, generally obtuse. 3 amadis. C Shell conic, light, often trans- ~\ grandis. ) versely striated ; spire concave, f J4nfl,f}i,v,ti/,nj/m duplicates, j elevated, and pointed; outer \Anteddumanum. australis. C. lip deeply sinuated above. J This, perhaps, is one of the most remarkable instances of analogy yet brought before the reader ; inasmuch as the characters used as analogies are those only by which the shells of each group, or sub-genus, of Conus and Coronaxis, can be defined. Nothing additional, in fact, can be added to separate, for instance, the sub-genus of Conus, whose type is C. litteratus, from its represent- ative, C. marmoratus, in the genus Coronaxis : so per- fect are these resemblances, that we do not actually know where the two groups join and unite. As to the circularity of each, there cannot, we apprehend, be the least doubt ; for the intervening shades of difference are so gentle, that we hardly know where one type ends, * The names of the types are in Italics those of the annectant species in Roman. CHAP. V. GENERA OF THE CONINE. 149 and the next begins.* Such only are natural and per- fect groups : they are the delight of the philosophic naturalist, and the torment of the mere nomenclator. As Conus is the most numerous in species, so it is the most perfect in these gradations, by which its five sub-genera are blended into one circle. The superior heaviness which belongs to the two typical divisions in each, is very singular, and may, probably, be owing to the internal volutions of their shells not being so much ab- sorbed as in the other types : a simple section, however, will, no doubt, explain the cause. (138.) Whether Conus dormitor, and other fossil species, really constitute the analogous genus in this circle to the Pleurotomee, cannot be determined, as no recent species, that we know of, have been discovered : we shall, however, regard them in this light under the generic name of Conorbis. The only remaining genus is that of Conella, hitherto overlooked among the di- versified shells placed in Columbella by Lamarck, where they continue to the present day. They are all very small, and perfectly resemble Cones in their shape ; but they may be easily known by the outer lip, which ad- vances upwards on the spire, and is marked internally by distinct elevated striae. This is a most interesting group ; for it not only connects this and the succeeding sub-family of ColumbellincB in the most satisfactory manner, but, at the same time, it preserves an affinity, on the other hand, to Conorbis. (139.) The CONINE, thus arranged, form themselves into the five following genera, analogous to the primary divisions of the Strombidce. The genus Conella (fig. 17- a.) connects this and the last sub-family. * There is one rule, however, which we have found quite sufficient for this purpose. If, of three characters of a given type, a species possesses only one, and that but slightly developed, the probability is, that it really belongs to the next type ; or the question may be decided by the law of re. presentation. Every natural and perfect group, of whatsoever value, con- tains representations of all the other four groups of its own value in that circle which unites them all. Thus, it will not be difficult for the natural, ist to discover, in that sub-genus which includes Conus slriatus, represent- ations (among the species) of all the other four. L 3 150 SHELLS AND SHELL-FISH. PART Analogies of the CONINE, or Cones. Genera of the , . . Sub-families of CONINE. Analogies. STROMBIOL. CONUS. Spire short, smooth. Typical. CONTUSE. CORONAXIS. Spire coronated or nodulous. STROMBIN.E. TEREBELLUM. ? CERITHIN^. CONORBIS. f A£Z**2fig *"* "* ** ^ *} P^ROTOMIN*, CONELLA. Outer lip striated internally. COLUMBELLINJE. The third analogy, not being apparent in the shells, probably may be traced in the animals. But this is not very material, since the whole arrangement is founded upon affinities, and all the other analogies are perfect. (140.) The COLUMBELLIN^B, or dove-shells, although of a small size, rather smooth, and without any dilation of the outer lip, have, nevertheless, very much the aspect of little wing-shells ; this impression originates in the thickened angle or hump on the upper part of the outer lip ; a character which is seen in no other group but that of Strombidea, and in certain Marginellce, — both which, in fact, are legitimate representatives of Columbella. According to Guilding, the animals of this group, like that of Conus, have the operculum so very small as often to escape detection. (141.) The result of an attentive analysis leads us to arrange the whole of these shells under the five fol- lowing genera : — 1. We retain the name of Columbella to the C. mercatoria, and the other European species, where the crenated teeth of the reflected inner lip ex- tend its whole length, and are regularly graduated, those on the inner being but slightly developed. 2. In Pusiostoma, the teeth on both sides of the aperture are much more developed ; those on the outer lip are crowded, very thick, and only occupy the middle por- tion. Both these, but particularly the last genus, have the top of the lip so gibbous, as to form a prominent and even projecting angle : they constitute the sub-typical and the typical groups, and consequently exhibit the CHAP. V. GENERA OF THE COLUMBELLIN^E. 151 characters of the ColumbelliniB in the highest perfection. The three aberrant genera are more diversified. Thus, Conidea (fig. 17. 6) has the general form of a short fusi- form mitre (like Mitra contracta*), or that of a cone with the spire as long, or longer, than the body -whorl, but still with the volutions thickened at the suture, and the aperture narrow : there are a few tooth-like striae on the inner part of the outer lip ; but it is not thickened in the middle : the inner lip forms an elevated ridge at the base ; parallel to which is a longitudinal elevated fold slightly crenated ; but the tuberculated teeth on the pillar are entirely wanting. In some species the spire is rather lengthened, with the aperture widened : and this change brings us to the 4th genus, Nitidella (c), where the inner lip and its fold totally disappear ; the upper part of the pillar, or rather that side of the whorl which forms the aperture, is flattened, as if pared down arti- ficially (as in Purpura) ; the base is finely striated, as in Ancillaria, and is terminated by a distinct plait (sometimes two), such as is seen in Folutilithes. All these resemblances point to one type of structure, and intimate this to be the most aberrant sub-genus of the Columbellina. There are many species, but all small ; the most common of which is the Colutnbella nitida of Lamarck t, a little West Indian shell, in almost every collection : the outer lip is either smooth or slightly striated within; but although the edge is slightly thickened, it is never contracted in the middle — nor is the margin, although inclining inwards, decidedly * Zool. in. 1st Series. f Nitidella marmorata. Sw. (fig. 17. c.) T, 4 152 SHELLS AND SHELL-FISH. PART I. inflected : hence these shells, on a cursory glance, much more resemble the Buccininte than the Columbellince : they are almost always smooth, and generally shining. The 5th and last genus is Crassispira. (fig. 17. d.) These are also small shells, having the outerlip, externally, almost as thick as in Pusiostoma, but with a distinct notch at the top ; this notch is in the same position, but not near so deep, as in the club-shaped Pleurotomince : like them, also, the spire is rather long, and the base very short ; so that at first sight they remind us of very small Cerithince : the aperture is contracted both above and below, but wide in the middle ; thus being precisely the reverse to that of Pusiostoma, which is contracted in the middle, and wider at the extremities. These shells, of which there are several species, are known at once from the Pleurotomince, to which, however, they lead, by the outer lip being inflexed and much thickened, and by the sinus not extending beyond the margin. In such species as unite with Pusiostoma, the aperture is slightly toothed, and much contracted ; while in those, on the other hand, which pass into JVitidella, the shell is more fusiform, the mouth more effuse, and the outer lip thin. These variations, which would otherwise be unaccountable, are fully explained by the relations that this singular little genus bears to the two adjoining groups of the Columbellina, and render it one of the most natural in the whole family. Analogies of the GENERA of the COLUMBELLINJE. Genera Typical Genera of the Analogies. of the ColunibellincB. Strombidte. Columbella. Sub-typical ; shell coniform. CONHS. «•— »• C The outer lip often forming a si-T Nitidella. < nus at the upper part ; aper- >• PLEUROTOMA. (. ture effuse. 3 f Aperture very narrow; whorls } MAP™™ i thickened at their suture. 5 This table is drawn up for the especial purpose of CHAP. V. ANALOGIES OF THE COLUMBELLIN^. 153 explaining the singular mixture of characters concen- trated in this sub-family j for the only one by which all its genera are bound together,, consists in the outer lip being invariably inflexed, and either striated or toothed. Some of the analogies are weak, others strong; but as they follow each other in the same series as that of the primary divisions of the family, this regularity, of itself, is quite sufficient for our purpose. The sin- gular tuberculated tooth at the bottom of the aperture, in several of the Nitidellce, their flattened pillar ter- minated by an internal fold, the absence of a definite inner lip, and the effuseness of the aperture, are all explained, by the following table. Analogies of the Genera of the COLUMBELLIN^U Genera Sub-families Genera Sub-families of the Analogies. of the of the of the COLUMBELLIN.E. VOLUTIN^E. VOLUTIN.E. MURICID.E. Colurnbella. Sub-typical. MITRA. CYMBIOLA. MDUICINJE. Pustostoma, Typical. VOLUTA. VOLUTA. CASSINJB. C Outer lip much } Crassispira. < thickened, and >• M A RGINELLA. SCAPHELLA. BUCCININ^. C notched above, j f Obsolete plaits af| | the base of the | Nitidella. 4 PJJJJJ.J ap2$JJ" > ANCILLARIA. VOLCTILITHES. PURPURINJE. I times with an in- 1 I ternal tooth. J r Spire short; inner} Corudea^ 4 lip much deve- > OLIYA. HARPULA. NASSINJE. 1 loped. 3 (142.) But the Columbettince possess other resem- blances, among which that to the mitres has been thought so strong, as to induce the early reformers of conchology to place them both in the same genus ; hence it was taken as a resemblance of affinity. We have seen, how- ever, by the analysis of the Volutidfe, that this idea is erroneous. The impression undoubtedly originated in the strong resemblance between the strombiform division of the mitres, forming our genus Harpella, and the typical ColumbellfB. Yet even this, although a striking instance of relationship, is only analogical, as will be seen more clearly by the following table : — 154 SHELLS AND SHELL-PISH. PART Analogies of the STROMBID^E and the MITRIN^E. STROMBUS. Shell generally rugged. Tiara. PLEUROTOMA. "1 '• ** of the outer Conoehelix. CERITHIUM. ? Mitrella. (143.) Without going further into particulars, we may observe that these tables afford strong collateral evidence that the strombiform structure — at least, in this order — is one of the PRIMARY TYPES of form, which is repeated and represented, under every possible modifi- cation, in almost all the groups hitherto noticed. (144.) The PLEUROTOMINJE is our next sub-family. The perfect gradation of forms which connects this remarkable group with the cones, will, it is presumed, remove all doubts as to its supposed affinity with the FusincB. Nothing, indeed, short of the evidence here adduced would have satisfied us that Lamarck was in error in approximating Pleurotoma to Fusus : so strong are early impressions and preconceived opinions. The discovery, however, of the genus Crassispira brings into this group, by means of the new genus Brachytoma, a small group of shells, having the aspect of some Lamarckian Fusince, but with the basal canal longer, and the spire shorter, than Crassispira. One of the most typical has been aptly named Strombiformis* • it is tur- reted and nodulous, with the notch at the top of the outer lip short, and nearly semicircular, — hardly more developed, in fact, than it is in Crassispira. There are several other species, mostly nodulous, and having the general appearance of such shells as Fusus Syracusensis. We next come to the typical genus Pleurotoma, where the channel is so much lengthened as to be little shorter than the spire. These appear to be succeeded by a group * Sow. Manual, fig. 381. CHAP. V. GENERA OF THE PLEUBOTOMINuE. 155 to which we have retained Lamarck's original name of Clavatula ; it has the long narrow slit of Pleurotoma, but with a very short canal. Following this comes Clavi- cantha, having the canal equally short ; but the sinus, or notch, instead of being linear and long, is short and wide, the surface is rough, and the whorls either coro- nated with prickles or with compressed nodules resem- bling spines. The last genus is Tomella, which has the spire and canal nearly equally fusiform ; but the former is of very few whorls, and the inner lip is considerably thickened within, where it joins the outer lip. In these five genera, all the varied species of this group will arrange themselves : the two typical are recognised by the length and narrowness of the sinus, which, in the three aberrant genera, is short and wide. Clavicantha is a very remarkable form, inasmuch as it seems pro- bable that echinata and auriculifera * are fluviatile shells. Lamarck describes them as PleurotomcB; and not having seen them, we take his authority for the fact ; but we might almost question whether they do not belong to Potomis, which is the first genus in the Cerithince, — so intimately do these sub-families appear connected. Nearly the whole of these shells, like the mitres, are scarce ; and yet the species are numerous. They chiefly come from the Indian seas, and other warm latitudes. (145.) The situation and the genera of the Pleuro. tomince, thus determined by analysis, offer some very curious analogies which merit our special notice. The sinus, which gives them the appearance of having the outer lip dilated, although it is really not so, is only a modification, as we believe, of the wider sinus nearly in the same part of the outer lip in S trombus; and these, again, are but different modifications of the same part in the typical cowries, where the outer lip forms a sinus before it joins the umbilicus or depression of the spire. That this fissure is intended to admit the 'pro- trusion of some particular organ of the animal, is un- * Ency. Meth. pi. 439. figs. 8. 10. 156 SHELLS AND SHELL-FISH. PART I. questionable; but, until we know what the structure of this animal really is, nothing further can be determined. A similar notch is found in the genera lanthina, Scicu- relict, and Pleurotomaria, among the phytophagous fami- lies ; and the slit, in certain Emarginulce, may probably be analogous. By disposing the genera in the order they have here been placed, some interesting analogies will come to light. Analogies of the PLEUBOTOMIN^; and the STROMBIDJS. ****** Characters. STROMB^A. PLEOROTOMA. «™ PTEKOCERA. CLAVATULA. Sub-typical; canal short. STROMBUS. CLAVICANTHA. Canal very slight. APORRHAIS. TOMELLA. Inner lip considerably thickened. ROSTELLARIA. (146.) We now turn to the CERITHINJE, or club- shells, the last division of the family. They merit this name, not merely from their shape, but from having the whorls encircled, either with obtuse spines, nodules, or granu- lations. To M. Quoy we are indebted for a knowledge of the animals of three of the genera, each of which has some marked and peculiar character, — -more so, even, than their shells. Hitherto, with the exception of Potomis and Pirena, they have been placed in one genus. These two, from being covered with a strong epidermis, are presumed to be fluviatile, or, at least, living in the estuaries of rivers ; the rest are found in marine but generally shallow depths, and often in pools left by the tide. The species are numerous, both in a recent and fossil state, particularly in the newest form- ations, where some are stated to occur precisely simi- lar to those now living. The whole of these shells have a very long spire, a small body-whorl, and the outer lip considerably dilated. The first genus is Brongniart's Potomis, which may be called the coronated type, be- ing encircled with obtuse spines and granulated points ; CHAP. V. GENERA OF THE CEBITHIN^E. 157 the basal canal is scarcely developed, so that it merely forms a sinus ; the epidermis is strong, and of a rich fulvous brown, beneath which the shell is white. The typical genus Cerithium appears to follow next, chiefly distinguished by its short and nearly straight canal : the operculum is oblong arid ear-shaped, and the pillar smooth. These almost insensibly glide into Rhino- clavis — well distinguished, however, by the shell having a distinct plait on the pillar ; the basal canal fully de- veloped, and turned backwards ; and by the operculum being perfectly circular. These are very elegantly marked shells : the colour is generally white ; and the surface is often reticulated into little asperities, some- thing like those on a file. To these succeed Terebralia. generally of a black colour (as representing the Mela- niance), of a large size, and having the outer lip so much developed, that in almost all, when fully grown, it actually joins the other, and leaves only a circular opening for the respiratory siphon of the animal : this siphon, as shown in the admirable figures of M. Quoy, assumes the shape of a radiated star, which occupies the perforation, but does not protrude beyond it : the tentacula are very long ; and here, for the first time, we begin to see the commencement of that high deve- lopement of the eyes, for which the next groups, or the PterocercB and the Strombi, are so much distinguished : the operculum, as in Rhinodavis, is round ; but there is no plait upon the pillar, and the basal canal hardly pro- jects. The genus Pirena * completes the circle, by showing us a truncated based Cerithium, with the sinus of a Pleurotoma. These shells, like Potomis, are flu- viatile ; and thus we return to the point from whence we began : the variations, however, are so few, that the analogies are not striking. (14-7.) That the Cerithince pass into the Strombince, by means of Aporrhais, we have, individually, no doubt : we ground this belief more upon the similarity * Ferussac has most unaccountably joined this very beautiful and dis- tinct type with Melanopsis. 158 SHELLS AND SHELL- FISH. PART I. of their animals, than of their shells ; and yet, when we look to the young shells of Aporrhais, and of certain Terebralice, they might very readily he placed in the same genus : the cuts (fig. 15.) already given at p. 142. will bring this fact more prominently before the reader. We are not so confident, however, in regard to the abso- lute affinities of certain species of Potomis, which have the aperture oval, and the basal channel almost oblite- rated : they may, indeed, be the connecting links between Pol. muricata and the genus Clavicantha ; but until La- marck's Pleurotoma echinata and auriculifera are better known, some doubt must hang over them : on the other hand, this is the point of union between the two great tribes of the Zoophaga and the Phytophaga ; so that the very first genus which we should have to notice, if we followed the thread of affinity in this direction, would be that of Melania, in the family of the Turbidce, — be- ing precisely that to which these aberrant species of Potomis, with an oval aperture, would seem to belong. CHAP. VI. ON THE PHYTOPHAGOUS TRIBE OF SHELL-FISH. THE PRIMARY DIVISIONS OR FAMILIES. THE HELICID^E, OR LAND AND FRESH- WATER SNAILS. (148.) THE second great tribe of the gastropod shell- fish is that to which, after the illustrious Lamarck, we apply the name of Phytophaga, since they not only sub- sist upon animal, but also vegetable, substances : they are easily known from the truly carnivorous tribe, by being destitute of the respiratory siphon, and in the mouth not being retractile, or proboscidiform. In regard to the shel:s, the differences are equally well defined. From the absence of the respiratory tube, the aperture is round and entire, or at most is only slightly notched in such genera as unite the two groups. The CHAP. VI. THE PHYTOPHAGA GENERALLY. 159 whole are regular spiral shells, — a character by which they are separated from the Scutibranchia, or limpets. The great majority are external shells , and all hut one small group — the slugs and their representatives, — have their habitation sufficiently large to contain the entire body. Their modes of breathing and propagation are various, and greatly diversified even in genera close to each other ; so that nothing can yet be determined of a general nature on these points. Although the greater part of the Helicidce, or snails, live upon land, and therefore breathe differently, a portion of the same family live in fresh water ; and even some of the slugs appear to be found only on the sea shore : the rest of the tribe, excepting the Melaniance, are all marine. (149.) The secondary divisions or families are first distinguished by the formation of their animals, and secondly, by the nature of the shells : this latter mode, however, will lead to great confusion, if not regulated by the former ; since there are many genera in different families, whose shells are nearly of the same form, although inhabited by very different mollusks. As this will become evident when we enter into their details, we shall at once characterise the chief divisions. The first, or the most typical, are the Helicidee, which in- cludes the testaceous land snails, the naked slugs, and the pulmonary fluviatile shells.* The second, or Tro- chidfB, are entirely marine : the shell is almost always perlaceous ; the body of the animal is furnished with lateral filaments, and its mouth with lips, as in the last ; and the shells of both are turbinated and spiral. The third, or Haliotidce, are known by their flat ear- shaped shells, having only the rudiment of a spire, and without any pillar : hence they may be even called spiral limpets. The fourth is the Naticida, or nerits, where the spire also is very small, but the pillar is always thick ; the exposed part, or inner lip, often very broad ; and the animal slug-shaped. The fifth, or * This group corresponds with a few trifling exceptions, to the Pulmo- naria of the Rlgne Animal.. 160 SHELLS AND SHELL-FISH. PART I. Turbidce, can only be characterised effectually by their animals : they bear a close resemblance, in their eyes, tentacula, and mouth, to the Zoophaga, and several of the genera, as Turbo, Ampullarla, &c., are provided with the same sort of siphon : the shells themselves are all more or less spiral, and exhibit some of the most elongated forms in the whole tribe. (150.) The slight degree of analogy between the families of this tribe and the zoophagous Gasteropoda will, no doubt, be strengthened hereafter, when the animals of each are better understood. Analogies of the PHYTOPHAGOUS and ZOOPHAGOUS GAS- TEROPODA. HELICIDJE. Typical. MURICID.E. TROCHID/E. Sub typical. TURBINELLIDJE. C Foot enormously large ; tentacula C Foot enormously large ; tentacula ) -< very short ; spire of the shell > VOLUTIDJE. C very small. 3 y Shell highly polished, partly or 7 ? entirely covered by the animal, j T Animal carnivorous ; mouth pro-O TURBID;E. < bosciform, with a respiratory?- STROMBID.E. C siphon. j Without dwelling upon these points, therefore, we shall take a detailed survey of each of the families. (151.) The HELICID^: is one of the most remarkable families in the whole order of the Gasteropoda, in as much as it is the only one of the truly testaceous divi- sions, wherein we find mollusks entirely naked closely and intimately united to others which have perfectly formed shells. To separate the naked slugs from such as begin to have the rudiments of a shell, and these latter, again, from others, like the garden-snails, whose habitation is sufficiently large to contain them, would be such a violation of nature as no writer, has yet at- tempted ; we must, therefore, include them in the same family. We may account for this apparent anomaly, by supposing that, as this is the pre-eminent type of the phytophagous Gasteropoda, nature, so to speak, has, more CHAP. VI. HELICID.E, OB SNAILS. l6l distinctly than in any others, pointed out the mode which she pursues in the development of all her groups. Commencing from the most simple form, she gives us the first germ of the limaciform structure in the extraordinary genus Herpa, hereafter noticed. From this point, as it were, she makes two diverging series ; the one to the right hand, through the terrestrial slugs ; the other to the left, through the semi-aquatic slugs and the freshwater snails : and these two series, after passing through numerous links, finally meet in the pupaceous- formed shells, constituting the genera of Pupa and Clausilia. It is hy this theory we account for the actual presence of naked mollusks among the Helicidts; and in this manner do we consider that the whole form a circular group, the particulars of which will be more clearly stated hereafter. (152.) The HELICID^E are the only animals of the Testacea which breathe atmospheric air. From this circumstance they have been considered, by some, in the light of a distinct order ; but their close and inti- mate connection with the Turbida on one hand, and even with the Trochidce on the other, clearly shows their situation to be intermediate, and that they, there- fore, only constitute a family group. The respiratory organs of these animals simply consist of a moderate- sized oval aperture, placed under the reflected edge of the mantle, which can be dilated or contracted at plea- sure ; hence there are no branchia, but merely, ac- cording to Cuvier, " a network of pulmonary vessels, which spread over the parietes and pulmonary cavity." The number of tentacula is variable, according to the different groups ; but they are usually four, — two long and two very short ; the former bear the eyes at their extremities, but these organs are only so far developed as to appear like black points. So far as we yet know, the greatest uniformity pervades the animals of all the Helicince, or turbinated land-snails, so that the minor divisions rest entirely on the structure of their shells ; but in the spiral snails (or the sub-family Achatince) 162 SHELLS AND SHELL-FISH. PART I. both the animals and the shells are more diversified. Hence, while scarcely any thing has yet been done in determining the genera and sub-genera of the HelicincK, nearly all' those of the Achatince have been named and defined. It is time, however, to quit these general remarks, and proceed to the sub-divisions of the family. (153.) We arrange the whole of this group under the five following families, which may be thus de- fined : — 1 . the Helicince, or testaceous snails, having perfect turbinated shells more or less depressed ; the aperture entire, but without teeth. 2. The Achatinte, or spiral snails, the spire of whose shells is elongated and conic. 3. The Limnacinfs, or river-snails, having only two depressed or flattened tentacula, and no oper- culum. 4. the LimacintB, or slugs, having either no shell, or one much too small to contain the body. And 5. the LucernincB, or terrestrial volutes, where the shell is orbicular, depressed, or flattened, and the aperture furnished with distinct teeth.* That the foregoing series is probably the natural one, may be inferred from the following table of analogies : — Analogies of the HELICID^J. Sub-families Families Families of Analogical Characters. of the of the HelicidcE. Phytophaga. Zoopkaga. ACHATIN/E. Spire mostly produced. TROCHID.E. MURICID^E. LIMNACIN.E. Outer lip considerably dilated. TURBIDJS. STROMBIM:. Animal much larger than its' loped in its mantle. {•Depressed, or the spire very} LUCERNINJE. 4 small; aperture furnished >HALJOTID^. c with plaits. J These analogies are, of course, only applicable to the types of each, and are intended to be so understood : * The injustice of the attempt made by M. de Feru?sac to substitute a new and artificial nomenclature of his own for the Hcttcidte, and so to cancel the previous generic names of Lamarck, Draparnaud.and of all his predecessors, is without parallel in this or perhaps any department of zoo- logy, and can only be equalled by the confusion it has caused. CHAP. VL. THE HELICIN-ffi. l63 we have stated them merely as a preliminary step, to show the general, not the particular,, resemblance of the primary groups. The extreme difficulty attending such an analysis of the HeUcince and the Lucernince, as is necessary to determine the sub-generic types, will prevent us, for the present, from entering into the de- tails of these two groups so fully as we shall do in regard to the others. We commence with the HELICIN^E, as the most typical group ; but, from the above cause, its analysis will be less minute than that of the other divisions. (154.) The typical sub-family of HELICIN^, although more numerous, perhaps, than any of the land -shells, has received less attention, in regard to its natural di- visions, than any group of the same rank. This has probably originated in two causes ; the entire similitude that runs through the animals, and the little variation, of a decided and very prominent nature, observable in the shells. Nevertheless, a closer attention leads to the belief that this group, within itself, will be found as diversified in its modifications as any, — less obtrusive, indeed, but promising the same results, when thoroughly analysed, as in all natural groups. As a whole they are immediately known from the Lucernina, or land- volutes, by never exhibiting a discoid shell furnished with plaits or teeth : the aperture of one division, indeed (Pupa), has these appendages ; but then the form of all the shells is spiral and elongated, and cannot there- fore be confounded with the Lucernince. The Helicidce, perhaps, are best distinguished by the aperture being without teeth and transversely oval, — a shape which re- sults from the depressed form of the body-whorl, which^ in the Achatince, is always oblong ; and this character is the more important, because it is preserved even in such genera as Geotrochus, whose spire is often as conical and as much produced as that of the Bulimi. It is also to be ob- served that, with very few exceptions, these half-spiral snails have the tips of the spires very obtuse arid even flat- tened; whereas, in the AchatirMZ, they are always pointed M 2 164 SHELLS AND SHELL-FISH. PART I. and comparatively slender. Our analysis of the Helicince not having been yet completed, we are only acquainted with the four following genera ; the fifth, which should intervene between Helicella and Pupa, being yet unde- termined. In the first, or Helix proper, we have the great proportion of shells usually so called, of which the Helix hortensis is a good example j they are strictly turbinated shells, the spire being very slightly elevated ; the body-whorl ventricose ; the aperture without teeth ; and the base of the pillar never separated from the outer lip : this is the typical genus. The second, or sub- typical, is Geotrochus, where the spire is always elevated, and composed of more than four whorls *, generally of five, and sometimes of six: the typical species are trochi- form ; but the sub-genus Pithohelix puts on the aspect of a Bulimus or Achatina. The third is Pupa, where the spire reaches its full development, and the aperture becomes nearly circular : by this character Pupa may be readily distinguished from Clausilia and all its sub- ordinate types. Our fourth genus is composed of the remaining portion of Ferussac's Helicellce, typically represented by those disk-like shells which are destitute of a pillar; the spire very short, and often sunk below the level of the margins (as in Planorbis) ; the body-whorl ventricose ; and the outer lip considerably thickened : this group has no indications whatever of the incipient teeth seen in Hemiodon, and yet it connects the land- volutes and the present sub-family of Helicince in the most perfect manner. We shall not in this place offer any conjectures regarding the fifth type, but proceed at once to give our analysis of the two typical genera, Helix and Geotrochus, so far as it has yet extended. (155.) The sub-genera of HELIX appear to us to be as follows : — The first, on leaving Helicella, is Hemi- cycla, distinguished from Helix proper by the broad and flattened margin of its outer lip, and by the absence of the inner, except occasionally a little tubercle, sufficient to point out its analogy to the Lucernina: ; but there * The last, or body- whorl, being excluded. CHAP. VI. SUB-GENERA OP HELIX, ETC. l65 are never any on the outer lip. In the second, or Helix proper, the spire is more elevated, the shell more globose, the umbilicus covered, and the outer lip more or less reflected : these obviously lead to Zonites, which chiefly differs in the outer lip being always thin, the spire more depressed, and the umbilicus more or less open. By degrees, however, the spire becomes more and more elevated, until, in that sin- gular shell Epistylia conica* (fig. 18. a), we have a Pupa and a Helix combined in one form. The last is a very beautiful type, already characterised as a sub- genus by Mr. Gray, under the appro- priate name of Strepsaxis, while its obvious affinity to Hemicycla brings us again to the point whence we commenced. (156.) The genus GEOTBOCHUS, in like manner, seems to take the following course, corresponding to ^x that of Helix. We give the name of Hemitrochus to certain trochiform shells, (fig. 19.), having the spire nearly as elevated as in Epistylia, but less thick ; the whorls much fewer, and the inner lip margined internally ; the basal whorl is not angu- lated, so that, if the spire were not conic, and the inner lip not thickened within, they might be arranged with Zonites. These shells at once bring us to the typical sub-genus Geotrochus proper, where the body- whorl in its widest circumference is more or less carinated, and the spire gradually tapering to a pointed cone ; it is, in fact, just the shape seen in the marine Trochuses : in some few species, chiefly small and European, the margin of the lip is thin, but in the more typical ones from tropical America it is thickened, dilated, and almost re- flected. Our next sub-genus, Pithohelix is as spiral as the last ; the spire, however, is obtuse at the top, the body whorl not angulated, and the aperture, consequently, rather higher than broad : such as have the spire * Helix epi&tylium of authors. M 3 166 SHELLS AND SHELL-FISH. PART more than usually produced,, resemble Bulimi, but with this difference, that the whorls are more ventricose and the top of the spire more obtuse; in some the base of the pillar forms a small sinus or notch before it joins the thickened outer lip, analogous to the Acha- tina ; but in that the margin is always thin, and the spire more contracted and pointed : something of this form belongs to our next sub-genus Geomitra (fig. 20.), founded upon a most extraordi- nary little shell discovered by Mr. Lowe in Madeira, and exhi- biting the only instance of coro- nated nodules on the whorls we are acquainted with in this family. The form is that of the last type ; but the mouth is thin and completely circular, like that of a Pupa, to which genus we consider it leads. As connecting Geomitra with He- mitrochus, we here place the fifth sub- genus Gonidomus (fig. 21.), which, in the distortion of its whorls, is a com- plete prototype of Strepsaxis. The ge- nera HELIX and GEOTROCHUS would thus appear to form two circles, whose sub- ordinate types may be thus stated. 21 Analogies of the Genera HELIX and GEOTROCHUS. Sub-genera of HELIX. Helix. Zonites. Epistylia. Strepsaxis. Hemicycla. Analogical Characters. f Body.whorl large, ventricose ; 7 i umbilicus none. J f Body-whorl depressed, narrow ; ) i umbilicus open. j C Spire elevated, obtuse ; body- } } whorl depressed, the margins > C convex. 3 Spire and whorls distorted. f Aperture or outer lip perfectly 7 i round. 3 Sub-genera of GEOTROCHUS. Pithohelix. Geotrochus. Hemitrochus. Gonidomus. Geomitra. These sub-genera agree sufficiently well to render any additional illustration unnecessary. We shall therefore CHAP. VI. SUB-GENERA OF PUPA. lj at once proceed to the genus Pupa, the passage to which has been opened by Geomitra. (157-) The genus PUPA we shall restrict to those maggot-shaped cylindrical shells whose body-whorl is larger than the others, whose spire is thickened in the middle, and which have no teeth on the inner lip ; the aperture also, in three out of the five sub-genera, is always round, but in the two others it is oval, on account of their blending into the genus Clausilia. Having analysed both these remarkable genera, we feel much more confidence in stating the types than in what has been said regarding those of Helix and Geotrochus. The type of this present group is that extraordinary and rare shell the Megaspira of Lea, of which a noble spe- cimen, containing no less than twenty-two whorls, is in our cabinet. The outer lip is thin, and the inner want- ing ; but there are four sharp plates close together at the base of the pillar, and a central one on the inner side of the body- whorl : it must be remarked that this shell, although of such excessive length, does not lose the apex of its spire, which is obtuse almost to its very tip : this is an important character, because it is carried on to our sub-genus Gonospira, where this part is the same, but even more obtuse : the volutions, however, are only seven, yet the shell has the same form as the last, so that the spiral whorls are nearly of equal thick- ness ; the aperture is more that of Pupa, being oval ; it is thickened all round, and there is a tooth at the upper angles. This leads at once to the sub-genus of Pupa proper, distinguished from both the foregoing by the suddenly-pointed shape of the apex, and the increased thickness of the two lips, which, as in Gonospira, are united : all the typical species in like manner have a tooth ; but this disappears irt such species as pass into Plicadomus, where the inner lip is entirely wanting, the aperture having a dilated margin, and perfectly entire, while the apex of the spire, no longer suddenly con- tracted, is obtuse : it is by this sub-genus, as we think, that the whole group is united to Geomitra ; and it may ju 4 168 SHELLS AND SHELL-FISH. PART 1. be observed, that in the strongly sculptured ridges of most of the species, a nearer approach is made to the coronated Geomitra (fig. 20.), than to any other land shell. The last sub-genus to be noticed was long ago characterised by the masterly pen and pencil of Guilding, but seemingly overlooked by our concholo- gists ; it is his Siphonostoma *, and is distinguished at once both by the animal and its shell (S. costata Guild., fig. 22.). The foot is remarkably short, while the spire of the shell is deci- duous, t. e. falling off soon after it has reached matu- rity ; sometimes, indeed, the animal has been captured before this process takes place : the shell is then re- markably beautiful, exhibiting as many whorls as Macro- spira, but with this difference, that the upper portion is gradually attenuated to a fine point : this type is thus separated from Macrospira, not only by its decidu- ous spire, but by its round aperture and its thickened lips, which gives it all the aspect of a Cyclostoma, except that the margin of the lips, in some species, is even detached from the body-whorl. That there will be intervening modifications between each of these sub- genera, so that they may be blended more harmoniously together, can admit of little doubt : our only regret is, at present, that they are too strongly marked and dis- tinct ; nevertheless, we may feel confident, after studying the annexed table, that these forms follow each other in the order in which they are now placed. We insert in this place the series of the Clausilice, which represent Pupa, in order to show the intimate relations of the two groups ; but we shall subsequently return to that genus, because it forms part of the sub-family Acha- tince. * Guilding imposed this name after he had discovered that Brachipus had been used by us to designate a group of birds. CHAP. VI. ANALOGIES OF PUPA. Analogies of the Genera PUPA and CLAUSILIA. ra Sub-genera Genera of Analogical Characters. of of the PUPA. CLAUSILIA. HELICIN*. r Sub-typical; whorls numeO Megaspira. 1 rous, all persistent : urabi- >Balea. HELIX. C licated. 5 f Typical; spire deciduous 57 Siphonostoma.< Jips generally detached from > Clausilia. GEOTROCHUS. C the body-whorl. 3 f Outer lip with the margin,} < considerably dilated, and > . C the edge reflected. 3 Plicadomus. < considerably dilated, and Macrodontes. PUPA. the edge reflected. Pupa. Gonospira. pp^reof^few whorls, and very j ? RELICELLA. The resemblances between the sub-genera of Pupa and those of Clausilia are too obvious to be dwelt upon ; but those between the first column and the last require some explanation. The spire of HELIX is al- ways obtuse, so is that of Megaspira ; in GEOTROCHUS and Siphonosioma, on the contrary, the terminal por- tion of the whorls is acutely conic ; and this form is carried to such an extent in the deciduous portion of some species, that they actually put on the appearance of being long-spired trochiform shells, instead of a portion only of that to which they really belong. He- licella and Gonospira agree in the paucity of their whorls; while the fifth type, which should represent Pupa, has not been determined. If we wished to carry our analogies into the zoophagous tribes, it is clear that the strombiform type is the third, and the volutiform the fifth, of the above series. (158..) We feel unprepared to offer any definite opi- nion on the extent or the subordinate types of the genus Helicella ; it stands at the confines of the HELICIN^: and the LUCERNIN^, and therefore may be supposed to par- take in the characters of both. We even think that several of the perfectly discoid shells, now arranged with Cyclostoma, such as Cy. planorbula*, will event- * Ency. Meth. 451. fig. 3. 170 SHELLS AND SHELL-FISH. PART I. 23 ually prove the real types of this group, which repre- sents Cyclostoma among the HELICIN^E. (159.) The ACHATIN^E, as we have already shown, constitute the sub-typical group, representing in their own family the zoophagous tribe. This analogy is seen in two ways : first, they are the most spiral of all the Helicidce, just as the Zoophaga are the most spiral of all the Testacea ; secondly, they are the only ones where the indication of a basal channel is seen, as if to pre- pare us for the full development of that character in the next great tribe which succeeds this. But setting aside all these considerations, at least for the present, we will at once proceed to characterise the five genera into which they appear to divide themselves. 1 . In Achatina, properly so called (A.marginata, Sw.fig. 23.), the basal extremity of the pillar is trun- cated, so as to present a distinct separation between it and the outer lip ; this lip also is always thin and sharp -edged at every period of age. 2. In Bulimus, on the contrary, the outer lip is more or less thickened and reflected backward; while the inner lip — always absent in Achatina — forms either a little fold just below or near to the umbilicus, or is continued up, and spreads a polish over the left side of the aperture : the general shape of the shell in the typical sub-genera of both this and the last is obovate, having the body-whorl much the largest, and the aperture without teeth, except in the sub-genus Auri- cula. This leads to the next or 3d genus, Clausilia : in these the spire is excessively long in proportion to the aperture, the basal or body-whorl being hardly larger than the others ; and the aperture, moreover, is furnished with various folds, or toothlike process. The 4th, Helicina (fig. 18. b)} is distinguished at first sight by its CHAP. VI. THE SUB-GENERA OF ACHATINA. 1?1 rather depressed form, but still more by its semicircular aperture,, always closed by a horny operculum : the typical species are also peculiar from having a narrow notch, or rather slit, at the base of the outer lip. The 5th and last genus is Cyclostoma, distinguished by its mouth and operculum being perfectly circular ; the margin of the lip is also more or less dilated into a fringe or thickened rim. We shall now take each of these genera, and describe what appear to us the types of form or sub-genera in each. (160.) The first and typical genus, ACHATINA Lam., includes the largest sized shells of all those inhabiting the land : they are chiefly found in Africa, where the natives use them as food, and expose them for sale in the markets. The inside of the mouth is sometimes of a brilliant rose-colour, and the outsides of nearly all are elegantly marbled with white ; but, as the epidermis is very tenacious, the ground colour appears olive. The body-whorl of these typical species is large and ventri- cose, the outer lip simple, and the whole shell solid : but in the next type, or Cochlicopa of F£russac*, the body- whorl is more slender and cylindrical, and the shell is placed very much towards the end of the disk or foot of the animal, which makes this part appear very short : by degrees, however, the spire becomes length- ened, and the body-whorl proportionably smaller ; and in these aberrant species, nearly all of which are longi- tudinally striated, the margin of the outer lip is more sinuated. This elongation of the spire prepares us for the sub-genus Macrospira Guild., where the spire becomes excessively long and cylindrical ; yet the lip is still very thin, and the pillar is truncated, or notched at the base, precisely as in all the other types. In one or two species we observe, for the first time, a thickened fold in the middle of the pillar, analogous to what is seen in some of the Auricula and the Pupae. Now, * We adopt M. Ferussac's names whenever they have a right of priority and are classical ; this group has been called by the strange appellation of Polyphemus, as if the animal had not two eyes, but one only ! 172 SHELLS AND SHELL-FISH. PART I. this same thickening of the pillar into a central fold is observable in Leucostoma, — a name by which we now designate a remarkable little shell (fig. 24.) of the same shape as the more elongated Achatinelloe, but with the addition of a thick gibbous mass of white enamel placed on the top of the aperture within, where the outer lip joins the body-whorl: this little pad, in short, is exactly the same as what is seen in Melanopsis, — the base is distinctly emarginate, and the outer lip thin ; but then the substance is more like that of a marine than a land shell, and both the interior of the aperture, and the outside of the whorls, are transversely striated : the space between the upper pad and the commencement of the plait on the pillar is without) enamel, and is so short that it has the ap- pearance of a deep notch : that this shell, however, either by affinity or analogy, has a strong relation to the types where we now place it, admits of little doubt ; our difficulty lies in determining between these two relations. If not a marine, it may be an amphibious species ; in this respect it seems to have a relation of analogy to Melanopsis, as well as one, more near, to Planaxis. Achatenilla is our fifth and last type. These little shells are remarkable for the beauty of their colours ; they are all inhabitants of the Pacific Islands, where they are used as bead-like ornaments. They are at once known by the thickened rim on the internal part of the outer lip : were this rim external, nothing but the truncated pillar would prevent these shells being placed with the Cyclostomce. With Achatinella, in fact, the circle is closed Its connection to Achatina proper, with which our survey began, is effected by that well-known shell, the A. virginea, which is almost an aberrant Achatinella : in this well-known species, the aperture is very oblique, as in Achatinella pica, and the pillar, like that shell, considerably turned inward. The thick- ening on the inner margin of the outer lip is not CHAP. VI. ANALOGIES OF THE ACHATIN^E. 173 observed in young shells; and even in those which are adult it is very slight, yet it is distinguishable. In the typical Achatinte, on the contrary, the base of the pillar is turned outwards, the mouth is not ob- lique, and the whole of the outer lip is so thin and fragile, that it breaks on the slightest touch : a more intimate union, in short, cannot possibly exist. (l6l.) Having now, to all appearance, closed the circle of Achatina, we may compare it with the primary divisions or genera of this sub-family. Analogies of the sub-genera of ACHATINA. Sub-genera. Achatina. Cochlicopa. Macrospira. Leucostoma ?. Achatindla. Analogical Characters. ("Large; ventricose; strictly typi- > I cal $ f Body- whorl more contracted ; 7 i spire more lengthened. 3 'Shell cylindric; spire exces--) long ; the body-whorl f aperture short, nearly f r Outer lip with a distinct notch at } 1 the base ; inner lip not thick- > C ened internally. j f Lip thickened ; aperture nearly 7 £ round. J r Shell cy J sively 1 small ; (. round. Genera of the Aehatinte. ACHATIWA. BULIMUS, CLAUSILIA, HELICINA. CYCLOSTOMA, This result of following the course of affinities is im- portant, as showing that the modifications of the spiral snails are regulated on a uniform and a very simple system. The more experienced zoologist need hardly be reminded, that, in comparing Cochlicopa with Bulimus, we institute the comparison with that division of the latter genus which is sub-typical, because Cochlicopa is also sub-typical : in both these the spire is as long, and generally longer, than the body- whorl ; whereas in the pre-eminently typical Achatince and Bulimi, the body- whorl is ventricose, and the four whorls of the spire short. So beautifully do the greater part of these five sub-genera of Achatina blend and pass into each other, that it is no easy matter to determine where one ends 174 SHELLS AND SHELL-FISH. PART I. and the other begins. Leucostoma, however, is an exception ; it is more isolated, and consequently its pre- sent position is very doubtful. There is also a hiatus between Leucostoma and Achatinella; but then this last is so perfectly connected to Achatina, that nothing can separate them. Thus we have four fifths of a circle ab- solutely perfect; so that, if Leucostoma had been undis- covered, and the fifth type entirely wanting, still this deficiency would not affect the general principles of our arrangement, — we should still have four of the sub- genera intimately representing four of the genera ; and we should conclude, by inductive reasoning, that the fifth of the former, when discovered, would represent the fifth of the latter. (162.) The most numerous in species, and hence the most varied in their forms, of all these sub-genera, is that of Achatina proper. In consequence of this va- riation, the species, as is usual, assume the forms of the genera and families which surround them ; so that they might be called sectional types. An instance of this we have already shown in Achatina virginea, which, with its allies, obviously represents Achatinella ; then comes Achatina Zebra,, &c. as the pre-eminent types of all : following this, we have such shells as A. elongata Sw.* &c., with their longer spire, and thus assuming one of the chief characters of Cochlicopa ; while A. crenata t, and perversa f, &c., by their still more produced spire, immediately remind us of Macrospira : the de- pressed form of Ach. Sultana ^ finds its prototype in the unusually depressed Helicince ; and thus we have, in this single sub-genus, indications of all the genera of the sub-family. This is sufficient to show the neces- sity of rigid analysis, before we can determine what is the rank of a particular division, whether it be sec- tional, sub-generic, or even generic : the same may be said of higher assemblages ; for it is impossible to know, a priori, what groups are of the rank of sub-families or * Chem. pi. 119. f. 1124, 1125. f z°o1- Illustrations, 1st Series. J Exotic Conch. CHAP. VI. ANALOGIES OP THE ACHATINA. 1?5 families., before the whole tribe has undergone a careful examination. (163.) The foregoing series, constituting the sec- tional types of our sub-genus Achatina, will be ren- dered more plain to the general reader, if thrown into a table in the following manner : — Analogies of the Species in the Sub-genus ACHATINA. Sectional Sub-genera Genera Division of Analogical Characters. of of the the Species, ACHATINA. ACHATIN*. C Ovate ; ventricose ; spire T A. Zebra. < short; outer lip simple, > Achatina. ACHATINA. C not sinuated. j r Ovate; aperture nearly or} A. elongata. < quite entire; spire more V Cochlicopa. BUIIMUS. C lengthened. 3 A.PerVersa. A. Sultana. '^ *™ j ^ostoma , HEUC,NA. A.virginea. { ^^^T^ ™™* ' ^ ^hatinella. C^CLOSTOMA. Now, this is the smallest group which can be made out, next to the actual species which come under each section ; and yet every conchologist who possesses an extensive series of these shells, or even of those we have named, must perceive that no other divisions, or sec- tions, can be formed with any degree of propriety ; that is to say, if he were asked to single out the most diver- sified forms from the sub-genus Achatina, the above are those he would probably fix upon. Now, this series, small as it is, turns out to have a circular succession ; and not only that, but likewise to represent all the sub-genera and genera of the family. Hence it would seem that the essential character of this sub-genus is to have the contour of the aperture simple — not sinuated or dilated, as in the next sub-genus, Cochlicopa. The Cochlicopa maculata thus seems to be neither an Achatina, nor a distinct sub-genus, as some have imagined, for we do not believe it is a marine mollusk. (164.) The preceding analysis of Achatina inci- 176 SHELLS AND SHELL- FISH. PART dentally explains the essential characters of Cochlicopa. Quoy and Gaimard have figured the animal of the last sub-genus, and M. Ferussac of this, which is distin- guished by the very backward position of the shell ; but the typical form of Cochlicopa appears to be oblong ovate, the spire and aperture nearly equal, the whole shell distinctly striated longitudinally, and the outer lip forming a sinuated curve near its base ; the substance is almost always very thin ; and the colour is light fawn, never marbled or banded transversely, but sometimes longitudinally : those species which pass into Macro- spira have such a long spire, that, but for the oval aperture and regular striae, they would not be known. The species appear confined to the tropical latitudes of the Old and the New World. On the remaining sub- genera, viz. Macrospira Guild., Leucostoma, and Acha- tinella, nothing more can here be said. (165.) The next genus, BULIMUS, is a most exten- 'sive and varied one. It represents the typical Helices, or snails ; and has, consequently, the aperture perfectly entire, the end of the pillar being blended with the outer lip : except in one of the sub-genera, Auricula, the pillar has neither teeth, folds, nor plaits ; and even in this solitary group, the largeness of the body-whorl, the shortness of the spire, and the thickened margin of the outer lip, are all certain indications of its belonging to the genus Bulimus. The Bulimi, in fact, possess all the characters of the genuine Auricula, but without their folds. There is no perceptible difference in the animals of the two typical sub-genera ; and that of two of the others are unknown. (166.) We shall commence the survey of this ex- tensive group at that point where it joins Achatina. This union is effected by our new sub-genus Lepto- spira, which, as its name implies, has the spire exces- sively long and slender ; their form, in fact, is precisely like that of the Macroapira, but the aperture is entire, and the outer lip thickened. A remarkable shell in our cabinet, once the property of the duchess of Portland, CHAP. VI. HELICID.K. BULIMUS. 177 exhibits the typical perfection of this form : but there are others, much smaller, where the outer lip is thin ; and these are the connecting links between this and Macrospira. The well-known Helix decollatus Linn, seems to belong to this sub-genus, and conducts us im- mediately to Bulimulus of Leach. We now come to shells of the ordinary shape ; the outer lip is rather thin or scarcely reflected, and the inner so little developed that it merely forms a thin plate over the umbilicus, where this latter exists. Before we had sufficiently analysed this family, we were little disposed to adopt this sub-genus. Its characters are so very slight, and the greater or lesser reflection of the outer lip is so variable, that we did not think such considerations alone were sufficient to authorise the separation of these shells from Bulimus: more particularly as the exquisite draw- ings of Guilding did not show any outward difference in their animals. But no sooner had it become evident to us that Bulimulus, in fact, was the representative not only of Zonites, but of Achatina, than the full value of the distinction became manifest. There are not many sectional forms among these shells, which are all rather of a small size; but some, as the Bulimulus undulatus, Antiguensis, and Proteus Guild., are very elegant. The third sub-genus, or Bulimus proper, is a very numerous one. The fact is, that, being the pre-eminent type of all these sub-genera, it contains representations of all, and under more modifications than are found in Acha- tina proper. As we shall return to these shells subsequently, we may now pass on to Auricula, the fourth sub-genus, which, with the general form of Buli- mus, although less ventricose, unites the peculiar character of having one, or sometimes two, plaits on the pillar near the base of the aperture. The next genus, hitherto overlooked, is Gonyo- stoma (fig. 25.), represented by the Bu- limus of that name. The length of its spire, and the 178 SHELLS AND SHELL-FISH. PART I. distorted aspect of its mouth, — although quite unique in this group, — are not its only characters; for at the base of the aperture is a little emargination or notch, analogous to what is seen in Helicina, Leucostoma, and Anastoma. By the length of its spire, it evinces such an affinity to Leptospira, that we insensibly find we have returned to the group we commenced with. The sub- genera of Bulimus thus form a circle, without the absence of a single link in the chain of continuity. (167.) The sub-genera Bulimus and Auricula are the only two which will require further illustration. The first, from being pre-eminently typical, contains, like Achatina, sectional types, representing the five prin- cipal forms in this family. The Bulimus htemastomus (fig. 26.) is the chief of these, and is an exact counterpart of the Achatina perdix Lam. of the opposite circle. It is a large ventricose shell, with a spire much shorter than the body- whorl, and of only four volutions. In the next type, Bulimus interruptus* of La- marck, these proportions are not preserved; the form is more slender, the bodyrwhorl less ventricose, the spire more lengthened, and the whole aspect reminds us of Achatina regi- na t and its allies. These are followed by such shells as BuL lubricus Lam., having very much the cylindrical form of Pupa; the outer lip is nearly round, but there is no inner lip, or any tooth in the pillar. In the third mo- dification we see a complete prototype of the sub-genus Goniostoma, in that singular shell the Bulimus Lyone- tianus, where the aperture protrudes on one side, and appears distorted. Last of all comes those small Pa- cific species (mistakingly separated as a genus, under * Chemnitz, pi. 101. fig. 938, 939. t Zool. 111. 1st Series. CHAP. VI. TYPES OP THE SUB-GENUS BULIMUS. 179 the name of Partula), where the margin of the aperture, instead of being completely reflected, as in all the other types, is only very much dilated or spread out. This peculiar character brings us, of course, to the confines of the sub-genus Bulimulus ; and by such shells as the Bulimus melanostomus of Brazil (which will completely answer to the characters given of Partula*} we return again to B. hamastomus. By arranging these species in a column, as sectional divisions, they will be found to represent the primary types of the spiral land shells in the following manner : — Analogies of the Sectional Types of the Sub-genus BU- LIMUS. BULIMUS. ACHATINA. Sectional Analogical Sub-genera Sub-genera Types or Specie, Walter, ' Htemastomus. Interrupts Lara. CLAUSILIA. Lubricus. HELICINA. Lyonetianus. CTCLOSTOMA. Australis. ("Shell ventricose;1 j spire short ; | -^ aperture in the }> BULIMUS. j typical species [_ ACHATINA. always rosy. J r Shell more slen-} -J der; spire ele- V BULIMULUS. COCHLICOPA. C vated. J rSpirelengthenedfl | basal volution j -I smaller or very }> LEPTOSPIRA. MACROSPIRA I little larger L than the next J £ Aperture distort-} LEUCOSTOMA ? (. the base. ) f Outer lip thick-T ened more than ) lar ; aperture I ear-shaped. j * " PARTULA. Conical, smooth, spire equal to aperture in length, con- sisting of few whorls ; aperture auriform ; outer lip reflected, broad ; inner lip reflected, with a slight prominence on the columella." — Sowerby's Ma- nual, p. 77. If the student turn to the figure of B. melanostomus Zool. 111. 1st Series, he will find this description perfectly applicable ; yet this latter has been arranged as a Bulimus, and placed in a different family. N 2 180 SHELLS AND SHELL-FISH. PART I. The variations in the forms of the species are thus seen to be a primary character in all these groups, whether we look to the primary divisions or genera, or to their sub-genera. It is singular how very closely some of the little shells of Ferussac's Partula put on, as it were, the very colours of the Achatinettce, which they are to represent ; and even the " slight prominence on the columella" is analogous to the thickened fold-like ter- mination of that part in some Achatina: both, more- over, are chiefly found in the Pacific islands ; and both, by having the broadest lips of their respective congeners, aptly represent the Cyclostomce. (168.) The sub-genus Auricula, is no less interesting than the last ; because, although few in species, its re- lations are unusually complicated. We shall first notice those types upon which there can be few or no doubts, and then advert to such as are questionable. The know- ledge which Guilding's drawings of the Auricula un- dulata* has given us of the animal, clearly shows its close approximation to that of Bulimus hcemastomus, also figured by the same exquisite artist. This fact goes to es- tablish Auricula as a division of theBulimi, and we have to consider what other shells showaclose similarity to this. The species we may thus select, are the Auricula Dombey- ana, Auris-Leporis, Sileni, and Bovina ; and the whole group may be described as shells with the aperture rather larger than the spire, the whorls of the latter few and produced, the pillar one or two plaited, and the outer lip (except in Dombeyana t) thickened and reflected on he external edge. This latter definition would exclude Auricula midte, and those other dubious terrestrial spe- cies whose spire, although much shorter, is composed of more whorls. We suspect, indeed, that these latter shells are nearly allied (through Pedipes and Melampus) to Tournatella; in which case both them and the sub-genus Scarabus must be removed from the Helicid£e,and placed * Plecocheflus undulatus Guilding, Zool. 111. 2d Series, pi. 103. t I apprehend, however, that in perfectly adult specimens, this species has a similar outer lip to A. Sileni. CHAP. VI. AURICULA. BULIMUS. 181 with the TurbidfB. Certain it is, that these animals (made known by the excellent figures of the French voyagers) are very different from the Auricula undulata; they have only two short and depressed tentacuk with basal eyes, as in Pedlpes*, instead of the usual structure of these organs common alike to Auricula undulata and Bulimus hesmastomus. On these reasons do we restrict the sub- genus Auricula to the characters above stated — at least, until further inform- ation leads to a different conclusion. Of all the species of Auricula here named, the Auris-Leporis (fig. 27-) is the most remarkable ; the plait on the pillar is not real, inasmuch as it is not solid, but formed by a sharp angle of the body- whorl round the umbilicus; the aperture is large, and so oblique as to appear dis- torted. It is by this shell that we pass to the sub- genus Gonidstoma already mentioned ( fig. 25.). The five sub-genera of Bulimus will thus form a circle, and present us with the following analogies : — Analogies of the Sub-Genera of BULIMUS. Genera of the Turbida. Sub- genera of Bulimus. Analogical Characters. Genera of AchatintE. Sub-genera of Achatina. TURBO. Bulimus. I Body-whorl large, T ventricosej spire > short. 3 BULIMUS. Achatiiue. TURRITELLA. SCALAR! A. Bulimulus. Leptospira. i Body- whorl more ") slender; outer lip ( thin, or very f slightlyreflected. J Spire excessively 7 long; body-whorl > small. 3 ACHATINA. CLAUSILIA. Cochlicopa. Macrospira. SCISSURELLA. MELAMPUS. Gonyostoma, Auricula. i A slight notch orl channel at thef base of the aper- f ture. 3 Outer lip dilated; 7 the margin > spreading. 3 HELICINA. CYCLOSTOMA. Leucostoma ? Achatinclla. * See an cal Journal admirable memoir upon this genus by Mr. Lowe, in the Zoologi. , No. xix, p. 2SU N 3 182 SHELLS AND SHELL-FISH. PART I* If, therefore, the Auricula Midce* and Juda belong to the division of which Melampus is the type, they can he so arranged, without any detriment to the above table. The same may be said of Scarabus. We have, indeed, formed this arrangement in conformity with the struc- ture of the animals, rather than of their shells ; and resting upon this principle, we deem it preferable to err on the safe side, rather than to follow previous authori- ties on the subject. (169.) The next genus, CLAUSILIA, has hitherto been thought to form a part of the Pupte; the two, indeed, are united, yet they appear to form distinct groups. The present is distinguished by having the aperture ovate and ear-shaped; while in Pupa it is almost, if not quite, circular. The Clausilice, as a whole, possess the follow- ing characters : — the spire is invariably longer than the aperture, which is defended in all but one instance (Ba- lia Gray) with little ridged teeth, usually placed upon both lips ; they are all small and slender shells; and inhabit temperate rather than tropical climates. We arrange them as follows: — 1. Clausilia, where the thickest or largest whorls are generally in the middle of the spire, the tip of which usually falls off when the animal has added new whorls to its shell, — a wise provision of nature, observes Guilding, " since, its foot being short, it would not have the power of drawing along so heavy a shell :" the aperture is usually sinistral, but in the aberrant species it is on the right side ; it is very small, much contracted above, and is generally beset with teeth on both its sides. In Balia, however, these teeth disappear, and the mouth is dextral. The third, Macrodontes Sw., is a new and most interesting type, uniting the com- pressed teeth of Clausilia, with the form and size of Auricula. The few species we have yet seen of these * The representations of the animal of Auricula Midte, given by M. Lesson's Atlas (pi. 9. fig. 1.), are totally different from that of M. Quoy's : the former lias the tentacula and eyes of a Helix, the latter those of Sca- rabus— There must be some great error in one of these ! Is M. Lesson's design correct ? CHAP. VI. SUB-GENERA OF CLAUSILIA. 183 rare and remarkable shells are all from Brazil ; and they establish, in the clearest manner, the passage between the European ClausilicB and the South American Auricula. We have now arrived at that particular sub- genus which is to connect the present group with the genuine Pupa. This union is effected by those small European shells, hitherto placed in the latter genus, which we have sepa- rated under the name of Pupella. This sub-genus, in fact, may be looked upon as the common point of union where the sub-families Bulimina and Achatina are united. They are at once distinguished by having both sides of the aperture toothed ; and not, as in Pupa, the inner lip only. Some uncertainty hangs over what shells are the true types intervening between Pupella and Balia. The passage, indeed, is very easy, if we suppose it to be made by certain little shells of Europe (as the P. mus- corum, fragilis, dolium, and umbilicata of Drap.) which have no teeth on the outer lip, but sometimes one on the inner j while the shortness of their spires would distinguish them from Balia : or this, perhaps, is the place where some of the smaller shells, analogous to our Gonospira, should be placed ; at all events, we have in Pupella such a close approximation to Balia, that the circle of the genus Clausilia may be considered almost perfect : at all events, we cannot consider either Ala or Vertego as sub-generic types, merely because they differ from our Pupella by the position of their aperture ; while Azeca of Leach, as a sub-genus, is equally questionable. We presume, therefore, that the types here mentioned form the circle of Clausilia. We have already com- pared them with those of the Pupa, in conjunction with the genera of the HELICIN^B, we shall now, how- ever, bring the sub-genera of Pupa and Clausilia more immediately and exclusively together ; when it will be more readily perceived that the hiatus between Balia and Pupella might be filled up by some of the shells just mentioned. K 4 184 SHELLS AND SHELL-PISH. PART 1. Analogies of the Genera CLAUSIHA and PUPA. Analogies. Sub-genera of PUPA. Siphonostoma. Megaspira. Gonospira. Pupa. Plicadomus. f Spire exceedingly long, the upper > t portion deciduous. 3 f Spire greatly lengthened, the up- 7 i per portion persistent. 3 C Spire moderate, with few whorls, } J the tip thick and obtuse ; the f ") aperture generally without (" t teeth. } r Spire moderate, but with manyj 4 whorls of nearly equal thick- > L ness 3 f Whorls few ; the outer lip dilated 7 (. and broadly margined. 3 Sub-genera of CLAUSILIA. Clausilia. Balia* Pupella. Macrodontes. (170.) Our next genus is HELICINA, — a group of remarkable shells, of which, as near forty species are now known, the sub-genera may be advantageously charac- terised. This will be done in our systematic arrange- ment, and in the mean time a few general remarks is all that we can here insert. They are small helix-formed shells, distinguished by their semilunate aperture, which is closed by an operculum. We have not seen, as yet, any intermediate form which renders the passage between them and the last genus sufficiently cle"ar. The animal, as seen in H. occidentalis (fig. 28.), has been well drawn by Guilding; it has only two tentacula, with the eyes at the base. In this respect the Helicince, as Cuvier observes, have a close affinity with the Cyclostomce, many of which are also turbinated shells, and all are * I should conceive, theoretically and analogically, that Balia would represent Gonospira by its toothless aperture ; and that the prototype of Megaspira would be perfectly like Clausilia, but without any teeth or folds, and the spire (probably) persistent. CHAP. VI. SUB-GENERA OP CYCLOSTOMA. 185 furnished with an operculum. Nothing, perhaps, can better exemplify the artificial nature of Cuvier's Pectinibranchia, than his placing Helicina between the two fluviatile genera Ampullaria and Melania, and Cyclo- stoma between Scalaria and Valvata ; in both instances thrusting in a group of land-shells between two others which only inhabit water. This is the more inexcusable, because it did not originate in an ignorance of the ani- mals j and yet he observes that the Helicina;, "judging by the shell, are Ampullaria, in which the margin of the aperture is reflected."* The only reason assigned for placing Cyclostoma after Scalaria, is " because the aper- ture is entire, nearly or quite round, and operculated." t This is quite true, but every student will readily per- ceive that this is merely a remote analogy. (171.) The genus Cyclostoma, like the last, has the sexes distinct ; but this is the only one character in which they differ from the other pulmoniferous land and river snails. The passage between this and the last group is rendered unquestionable by such shells as Heli- cina elegans Gray, which has the characters of both united. The typical Cyclostomce are spiral shells, the last whorl being but little larger than that which precedes it. The orifice of the mouth is circular, and is closed by a horny operculum. The pillar is often wanting ; but this variation occurs in species so close to each other, that it cannot be considered a sub-generic character. They are usually found in dry arid situations: the island of Malta abounds with them, where thousands may be gathered on the scanty herbage of the rocks; and many elegant species oc- cur in the mountains of Jamaica. On coming to the aberrant sub-genera, we find great diversity in the form, although none in the aperture. In Cyclophora, the shells * Cuvier further remarks that the organs of respiration are arranged as in the Cyclostomce, and, like the latter, they can live out of water. That these two genera are naturally united, both by the animal and the shell, is thus admitted, while we can only say that they are both as terrestrial as the garden snail ; they cannot, in fact, live out of the air, as we always killed the animals of our specimens by plunging them into water, t Griff. Cuv. xii. p. 58. 186 SHELLS AND SHELL-FISH. are turbinated, and resemble those of Helios, although the tip of the spire is acutely conical, and not, as in the common snail, depressed. These obviously lead to the typical sub-genus Cyclostoma; and these latter, again, to the singular sub-genus Megalomastoma, — another ad- mirable group, detected and beautifully illustrated by Guild ing ; it is the representative of Pupa, from which it is distinguished by possessing a horny operculum. Cyclotus of the same accurate zoologist is another remarkable type : it is so much depressed, that it almost resembles a Planorbis, and, from not having any pillar, the umbilicus is open to the terminal whorl : the oper- culum is shelly ; and although the aperture is round and thickened, the inner lip is carried upwards in the form of a little siphon : this is very remarkable in a species we possess from India, and in another from the "West Indies. We are disposed, indeed, to consider this and Cyclophora to be the two typical forms of the whole group which represent Planorbis , just as the Lucernince do in the entire family of HelicidcB. Guilding founded his group upon one species ( C. fus- cescens}, which he found " with the spire corroded," in the woods of St. Vincent ; and, unfortunately, all the specimens found by him afterwards were dead shells, so that the animal is still unknown. Megalomastoma appears immedi- ately to follow Cyclostoma, because the M. suspensum Guild., in its shell, is a Cyclostoma; but the M. brunnea Guild., which is ob- viously the type, is so elongated as to resemble, at first sight, a Pupa. The animal of M. suspensum is often found suspended by glutinous threads (fig. 29.); it has the mouth rather elongated, proboscis-like, but deeply cleft; the two tentacula rather long, and the eyes at their Having now concluded the survey of the four CHAP. VI. THE LlMNACIN.fi. 187 great divisions of the HELICID^, which include all the land-shells and slugs, we may enter upon the fifth and last, which are aquatic. (172.) TheLiMNAciN^Eis that sub-family which con- tains the whole of those spiral fluviatile shells which, like all the Helicicke, respire hy a lateral perforation. It is difficult for the student to distinguish these river shells from those of the fluviatile genera in the next family ; but they are in general much thinner, and in no instance have the Limnacince even the vestige of an operculum. Like the Cyclostoma, these animals have but two tentacula ; but they are, in general, very short and broad, having the eyes at their base : their shells are all very thin, devoid of any bright colour, and the aper- ture is always simple, — that is, without any thickened margin. They appear to arrange themselves into the following genera : — 1. Planorbis, where the shell is disk-shaped, and with- out any pillar, as in our common P. cor- neus. (fig. 30.) 2. Limnceus, having a very large and wide aperture on the right side, and the basal whorl so large as to contain the whole animal. 3. Physa, where the aperture is much smaller, the base contracted, and the mantle so large that its two lobes fold over the shell. In the fourth sub-genus Potomophila, the shell very much resembles the last, but the pillar is marked with a distinct plait or fold in the middle : the only species we are yet acquainted with, is the Co- novulus bulimo'ides * of Lamarck. (fig. 31.) In this, as in innu- merable instances, analogy has been mistaken for affinity. It is clear there is a resemblance between this and the sub-genera Auricula and Conovulus ; but we think there is no doubt that this is a fluviatile shell, and, but * Ency. Meth. pi. 459. fig. 7. 188 SHELLS AND SHELL-FISH. PART I. for this fold on the pillar, it could not he distinguished from a Limnceus. The fifth and last type is Ancylus, composed of the freshwater limpets (fig. 32.), not even 32 mentioned by Cuvier, but con- stituting one of the most re- markable divisions of the whole group. (173.) The five genera, placed opposite to those of the genera of Achatina., and the sub-families of the Helicidte, will be found to represent each other thus : — Analogies of the LIMNACIN^J. Genera of the Limnacints. Planorbis. Ancylus. Potomophila. Physa. Limrueus. Analogies. Sub-families Genera of the of the Helicidce. Achatinee. The general analogies of the whole group may be first slightly touched upon. The Limnacina; occupy that station in the circle of the Helicida, which corre- sponds to that of the Cephalopoda in the great tribe of TESTACEA. Hence they are all aquatic animals ; and if this analogy is correct, it follows that Planorbis is the typical group, because, in their flat discoid shells, they perfectly agree with the equally depressed and convo- luted Nautili. We have seen, also, that in Cyclotus a strong approach is made to this very same structure. The little shells of several of the slugs (Limacinai), if no regard be paid to the animals, might very well be CHAP. VI. THE LIMACIN.E, OR NAKED SLUGS. 189 taken for freshwater limpets; so that the analogy is most complete. Potomophila, again, is the only type having any fold upon the pillar ; and Clausilia is the only genus so distinguished among the Achatince. It is the excessive enlargement of the hody-whorl which gives such a peculiar character to the turbinated snails ; and this renders them distinct from the Achatince : and the very same disproportion is observed in all the typical examples of Limn&us, of which the common L. stagnalis is a familiar example. The near approxi- mation of the amphibious genus Succinia to the group we have now gone through,, is abundantly obvious. While, from possessing four tentacula, with the eyes pedunculated, it cannot be brought within the limits of the freshwater shells ; it is, in short, as Cuvier has happily expressed it, " a Testacella, with a very large shell." As the systematic definitions will be here- after given, we need not dwell longer upon this sub- family. (174.) The sub-family of Limacincp, which contain the naked slugs, is admitted to be such a natural group, that this part of our survey may be considerably abridged. The first of the typical genera appears to be Limax, where the tentacula are four, and, in general, the vestige of a shell is placed near the extremity of the body. The second is typically represented by the genus Her pa of Guilding, in which the tentacula are either entirely wanting, or, as in the sub-genus On- chidium, they are only two in number, and very short. The determination of Herpa, as connected to Limax, is one of the most important discoveries in mala- cology that has been made for many years, not merely as to the fact itself, but to the inferences to which it leads : it may be considered, in short, as the germ, or first incipient developement of this immense family, from which all its innumerable modifications branch off. Its analogy to Planaria among the Parenchymata is abundantly obvious ; a relation well understood by its learned and acute discoverer, who thoroughly un- 190 SHELLS AND SHELL-FISH. PART I. derstood the difference between analogy and affinity*, so lamentably confounded by so many other naturalists, even of the greatest reputation. The analogy, again, which the large coriaceous mantle, or shield, of Onchi- dium has to the Chitons need hardly be adverted to. The three aberrant genera, Vitrina Drap., Stenopus Guild., and Succinea Drap., have turbinate shells, nearly or quite sufficient to include their bodies; but these coverings are generally thin and semi-transparent, with a wide aperture, a very short or small spire, and, ge- nerally, with only the vestige of a pillar. For the dis- covery of the singular animal of Stenopus cruentatus t (fig. 33.), science is likewise indebted to the lamented Guilding: it seems intermediate between Vitrina and Succinea, and will thus stand as the most aberrant of the whole. The connection of this sub-family to the freshwater snails is obviously effected by Succinea; while Vitrina leads immediately to Leiostoma, among the land volutes. The sub-genera not having yet been determined, we shall pass at once to the fifth division, which closes the circle of the Helicidce. (175.) The terrestrial volutes, or lamp-snails, LUCER- NIN.E, were named by Humphreys, — a name we retain for the whole group, which, as we have already seen, constitute a sub- family.^ They are well distinguished from the typical Helicince by three characters, any two * " Genus Planarifs facie quam plurimum analogum, ut Limacides re- spirationis modo, locis, muribusque omnino affine." — Guilding MSS. f See figures and description in Zool. Journal, iii. pi. 15. figs. 1 — 5. j Lamarck subsequently used the name Caracolla, which Ferussac wished to set aside for that of Helicodonta, a name which, even had it the priority, implies two errors ;— first, that they belong to the typical Helices; and secondly, that they all have teeth : we consequently cannot adopt the innovation. CHAP. vi. THE LTJCEBNINJB. 1Q1 of which, in douhtful cases, will almost always he a sufficient guide : — 1 . The very marked depression of their whole form,, and the great number of the spiral whorls. 2. The possession of teeth either on one or on hoth sides of the aperture : and, 3. The granulated, or distinctly striated, surface of the shell. As our analysis has not been carried down to the location of all the sub-genera, we shall merely, in this place, enumerate the primary groups or genera, with some few of the sub-genera, leaving the rest for the more systematic department of the vo- lume. (176.) The groups which appear to rank as genera, and which are therefore the first divisions, are the fol- lowing : — 1 . Lucerna, having the shell flattened and orbicular, the margin always carinated, and generally sharp; the whorls numerous; the surface granulated, but never striated ; and the aperture usually toothed, but the teeth confined to the inner lip.* 2. Lucernella, equally depressed with the preceding, but the margin of the body-whorl is rounded and convex ; the outer lip is always toothed, and there are opposite teeth on the inner lip. These appear the two typical divisions. The three aberrant are, the broad-lipped species of Ferussac's sub-genus Helicella, having the body-whorl unusually large in proportion to those of the spire, which is flat- tened ; the umbilicus deep ; the outer lip spreading, and diffuse, but rarely provided with any toothlike pro- jection : these form our genus Hemiodon. The next, or most aberrant type, is composed of a part of Ferus- sac's Helicogena, where the shell is granulated, the spire depressed, and the outer lip marked at its base with toothlike notches ; the spire is very small, and hardly makes three volutions : this is our genus Thelidomus. The wide aperture of these prepare us for Leiostoma, having the aperture remarkably large and particularly smooth and glossy, while the glazing of the inner lip is extended very much beyond its usual circumference. * Except in Anastoma, which represents Pupa and Clausilia. 19*2 SHELLS AND SHELL-FISH. PART I. This latter character is highly important, as showing the analogy of Leiostoma to the Limnacince, and its affinity to the half-testaceous slugs, or the Limacina. (177-) Looking to the above genera, with reference to their analogy, they appear to represent the following divisions in their own family, and in the tribe of the Zoophaga : — Analogies of the LUCERNIN.E, or LAND VOLUTES. Analog Charters. LucERNA. HEMIODON. Shell discoid; the spire depressed. LUCERNIN.E. THELIDOMUS. Spire of very few whorls. LIMACIN.E. L..OBTOMA. (178.) The typical genus LUCERNA has one peculiar character, — that although its outer lip is in general. toothed or plaited, these plaits are never seen upon the inner lip, or that part of the body-whorl which forms. the opposite side of the aperture. They are the largest shells of this sub-family, and are particularly abundant in the West India islands. Although decidedly de- pressed shells, their spiral whorls are numerous, and are very progressively graduated. We separate them into the five following sub-genera: — In Discodoma, the cir- cumference is carinated, the aperture angular, and without teeth; and the edge of the outer lip but slightly, if at all, reflected. In Lucerna, the teeth on the edge, or within the outer lip, are very evident. In Anastoma, they are extended all round the aperture, which is likewise turned, so as to be nearly on the same plane as the spire. Leaving these, we have an analogous form to Thelidomus in several small toothless Helices L. (our Lucidella), but which evidently, by their spire, belong to this group. Caracolla completes the circle by uniting to Discodoma, CHAP. VI. THK LUCERNELL^E. 193 from which it is nevertheless separated hy its circular aperture, analogous in this group, to Cyclostoma. As this is the European type, we have preferred retaining to it the sub-generic name of Caracolla, that the nomen- clature of such well-known species should not be dis- turbed. The whole group is composed of granulated shells. (179-) In the second, or sub- typical group, we shall find five sub-genera agreeing with those of the last. As a general character, the Lumrnellce may be known by the inner lip, no less than the outer, being provided with teeth : those on the former are either one or (very rarely) two, placed almost transversely, as if to guard the en- trance to the shell by rendering the aperture remarkably narrow ; the teeth on the outer lip are situated at its in- ner edge, and have no corresponding indented grooves (as in Lucerna) on the outer surface. All the Lucernellce, likewise, are convex on their sides, not carinated. It is only in the sub-genera Hemicycfa and Lucidella that the inner teeth disappear ; but the union of the first of these two with Cyclodoma is so obvious, that they cannot be placed in different genera. The first form on quitting Anastoma is Polydontes, of which the type is that sin- gular shell P. imperaiorof Montfort; it is remarkable for its aperture being surrounded by nodulous teeth, obtuse, and resembling large granules, while those of Anastoma are more properly folds or plaits : following this comes Lucernella, where the form of the shell is often globose, the umbilicus closed, and the teeth very complicated : these lead to the greatly depressed form of Cyclodoma, where the shape is sometimes as discoid as in the well-known genus Planorbis. These shells are almost always striated; and, although small, are highly interesting. A great number of species inhabit the mountains of North Ame- rica and Madeira, but probably not one half of those that exist have yet been discovered. In Hemicycja, the internal or left-hand tooth either entirely disappears, or is reduced to a little tubercle ; the outer lip makes a bold and dilated semicircle, the margin of which is broad and o 194 SHELLS AND SHELL-FISH. PART I. flattened, without being absolutely reflected backwards. Lastly, we venture to place a few small shells, having something the aspect of Helicince*, as a fifth type, under the name of Lucidella; they differ from the last by the comparative smallness of the aperture, which has one or two small teeth on the outer lip, but none on the inner : these appear to pass into Thelidonta ; and in this man- ner do we conceive the whole form a circle. Not having yet completed our analysis of the three aberrant genera, Pusiodon, Thelidomus, and Leiostoma, we shall not at present attempt to designate their sub-genera. De Ferussac has adopted a modification of Humphrey's name of Lucerna (which he writes Lucena) for that group, part of which we here call Leiostoma ; but how far he is correct in placing the richly-coloured shells upon his plates 12, 13, and 14. with that which we de- signate as the type — may well be questioned. The dis- torted body- whorl of Thelidomus, and its serrated outer lip, render it analogous to Lucidella, from which it differs altogether in the few and unequal volutions of its spire. The most interesting genus, however, is that of Hemio- don, which has a large dilated aperture, the spire scarcely raised, and a gibbous prominence more or less developed at the base of the outer lip. This is the last remnant of the toothed aperture so common in this sub-family ; and accordingly prepares us for the true Helicella, which compose the first genus among the Helicince. Thus do the LUCERNIN^E form their circle of affinity, connected on one side to the slugs by Leiostoma, which passes into Vitrina, and on the other to the land helixes, as just stated. * Such as Hdicina aureola, Zool. Journ. i. p. 16. f. 13. 195 CHAP. VII. THE PHYTOPHAGOUS GASTROPODS CONTINUED. THE TURBID^E, OR MARINE SNAILS. (180.) THE family of TURBID^ succeeds the last, and, like them, is composed of spiral shells, destitute of any pearly lustre, with the aperture closed by an operculum*: the differences, however, are so slight, that the two families can scarcely be distinguished by their shells alone. The animals of the Turbidce, how- ever, are remarkably dissimilar from those of the Helicida : they breathe by gills, like all the zoopha- gous families ; and, like them, the mouth of the major part is furnished with a respiratory siphon, and even a probosciform mouth : the tentacula are only two ; and the eyes are either basal, or on the sides of the tentacula. The animals, in short, often exhibit the carnivorous structure of the Zoophaga, while their shells are completely those of the phytophagous tribe : it is thus that the two groups are connected. The whole of this assemblage are comprised in the following sub-fami- lies : — The first is uncertain. 2. The Ampullarince, or apple-snails. 3. The Melaniana, or black snails. 4. The Turbines, or winkles. 5. The lanthince, or Oceanic snails. A general analysis of these will now be given ; this investigation we were, in a manner, forced into, from the impossibility of discovering any bond of union or of affinity between the heterogeneous genera of the Turbidce, as they now stand in our conchological systems. (181.) The first primary division by which this family may be united to the fluviatile Limnacince, is * Except in Melampus, and probably lanthina. o 2 196 SHELLS AND SHELJL-FISH. PART I. somewhat uncertain. There are several fossil genera, as Enomphalus Sow., OrUs, and Planaria* of Lea, of a discoid shape, whose animals are quite unknown, and will ever be so, if no recent species are discovered. Their shells, indeed, are intermediate between those of the Ampullarince and the Limnacince ; but then this dis- coid shape is found in so many different families, that their location here would be entirely conjectural. On the other hand, we have our choice of Valvata and Thallicera^: the first appears to us more like one of the genera of the Ampullarina; while the extraordinary animal of the latter, and the singularity of the shell, leads us to view it, with M. Deshayes, more as the representative of a sub-family than of a genus. May this, again, be the natural station of the semi-aquatic genera Melampus, Scardbus, &c., whose animals have certainly a strong resemblance to those of the Limnacints ? Into these theoretical questions we dare not enter ; difficulties are opposed to the adoption of each of these theories ; and we shall, therefore, choose that which appears to us, upon the whole, least liable to objection, — namely, the supposition that Thallicera stands inter- mediate between the Ampullarince and the Limnacince. The animal of Thallicera, like the Limnacince, is her- maphrodite : the head is large, flat, cleft in two lobes, which bear the two sessile eyes ; but these are without any appearance of tentacula ; the oper- culum is horny; and the animal is ma- rine. Such is the substance of the in- teresting facts made known by M. Quoy, who found the T. Avellana (fig. 34.) in abundance on the coasts of New Zealand. That it is thus allied both to the operculated marine Pectinibranchia by its shell * This name cannot be retained, having been long ago applied to a well- known genus among the Parenchymata of Cuvier, and of this work t M. Quoy, among his other brilliant discoveries in malacology, has the honour of making known the animal of Ampullacera. I trust he will excuse my proposing Thallicera, as a name not liable, like the above, to be confounded with Ampullaria. CHAP. VII. THALLICERA. AMPULLARINJE. 197 and its habitat, and to the pulmonary fiuviatile Lim- nacince by its animal, there can be no doubt. (182.) The shape of the AmpullarincK is most like the garden snails ; they are generally globose, the spire very short, and the body-whorl enormous. Many of them are very large, and none are of a small size. They abound in the rivers of tropical countries, both of the New and the Old World. Guilding has admirably de- lineated the animal of this and the sub-genus Ceratodes, and has thus determined the latter to be a representa- tive only of Planorbis. The animals, in fact (fig. 35.), of the present group are furnished with a respiratory siphon (a) ; and are, no doubt, carnivorous, as well as herbaceous. Most of them have the operculum horny, but in some it is shelly j and this, joined to the thin- ness or thickness of the outer lip, may serve to dis- tinguish the sub-genera. The genus Paludina seems to represent the last in the rivers of Europe, and is well distinguished by the greater length of the spire, as seen in our native P. vivipara; but there are many exotic species : the aperture is narrowed above, and generally protected by a horny operculum. Nematura appears a sub-genus whose operculum is shelly, and the aperture still more contracted. With this genus o 3 198 SHELLS AND SHELL-FISH. PART I. we also place the European P. impura Lam., and the West Indian P. parvula of Guilding (fig. 36. ), the ani- mal of which, according to his drawings, has the tenta- cula unequal, — that nearest the pillar heing almost twice the length of the other. It is as a sub-genus, also, of Paludina, that we are dis- posed to regard Valvata. The shells of this last remarkable type are mostly of the same form as many of the helix-like Cyclostomce; the aperture is also round, and closed with an operculum. The animal, which we have not seen, is described by M tiller as having the branchia, or gills, pectinated, and projecting from under the mantle, floating externally, and vibrating every time the animal breathes : on the right side of the body is a filament, which resembles a third tentaculum. (183.) Our third sub-family, MELANIAN^, is com- posed of those long-spired fluviatile shells which form the genera Melania andMelanopsis, together with that of Planaxis, as the most aberrant, and two others now first designated as Paludomus and Cerithidea. This, which we think is the typical sub-family of the Turbidce, is so numerous, that it becomes necessary to characterise the sub-genera ; for without this, the theory of their re- presentation could not be rendered intelligible. The animals of these shells are well distinguished from the last, by having their eyes more developed, and placed in the middle of the tentacula, while the mouth is elongated in the form of a proboscis. The genus which makes the nearest approach to the Ampullarince, in the globular form of the shell, the short spire, and the rotundity of the aperture, is that of PALUDOMUS Sw., formed to re- ceive those short-spired shells which at present are placed in that of Melania. The American species form the sub- CHAP. VII. BIELANIAN^E. THE GENERA. 199 genus Anculosa of Say (fig. 31. a}*, and almost resemble nerits. Notwithstanding the thickness of these shells, the outer lip is unusually thin, and the inner is like that of a Purpura, being broad and flat- tened. One or two species now before us are so like young ma- v\ ^y\\ r*ne turbos, that none but a y practised eye would distinguish them. Theyare,however,strictly fluviatile shells, having a horny operculum ; and are abundant in the Ohio. The next sub- genus is Paludomus proper (6) : they differ from Anculosa in being sub-spiral like the JBulimi, and in having both lips thickened, although not margined by a rim ; the outer one is slightly reflected and crenated, and the in- ner perfect and convex : these seem peculiar to the Indian rivers. In the next sub-genus, Hemimitra, the general form of Paludomus is preserved, but the whorls are coronated by spines. The whole are readily distinguished from the next genus, by not having the outer lip dilated at its base, the inner lip complete, the aperture wide, and the spire always shorter than the body-whorl.t (184.) The true genus MELANIA comes next. Amid the great diversities of forms it contains, even as we now intend to restrict it, there may be detected four, if not five, types or sub-genera; yet, with one exception j, they are all possessed of an entire aperture, and are more or less spiral. The animal, according to Cuvier, has a proboscis-like mouth, and the two tentacula bear the eyes half way on their external side ; the aperture is always oval, the outer lip thin, and is generally much dilated at the base. The five types of form, or sub-genera, appear to be these: — 1. Melacantha; 2. M elania ; 3. Po- tadoma ; 4. Hemisinus ; and, 5. Melanella. (185.) The first type which meets us after quitting Paludomus is Melacantha, of which the well-known * I consider this, however, as a form between Paludina and Paludomus. t Melanin conica, globulosa, and retusa, of Mr. Gray, Griff. Cuv. pi. 14., belong to this group. J The sub-genus Hemisinus. o 4 200 SHELLS AND SHELL-FISH. PART I. Melanin amarula and setosa are typical examples. The spire is short, and the volutions coronated ; the inner lip is merely a thin glazing ; and the base of the pillar is flat- tened. It will be remembered that Hemimitra is the coronated type of Paludomus, and is so like Melacan- tha on a superficial glance, that, but for the difference in their apertures, they might be taken for species of the same genus. From these we are gradually led to the typical division of Melania, whose spire is often as long as in Turritella. These shells are much lighter than those of the next group, Potadoma, which are more solid in their substance; the base of the pillar is not depressed or broad, but convex and comparatively thin ; it is like- wise, in most of the species, much straighter, while the base of the outer lip is more dilated. All the species we have yet seen of this sub-genus are decollated. We regard, as the most typical character, a slight thickening of the inner lip, particularly at its upper part, because this is never seen in the last group. Our next sub-genus, Hemisinus, has hitherto been placed with Melanopsis, as the base of the aperture is notched : the type is the Me- lania lineata *: in its general form, indeed, it resembles the preceding shells ; but the body-whorl, although more ventricose, is yet contracted at its base, the outer lip but slightly dilated; and the inner lip (now for the first time clearly developed) is complete, — that is, it extends from one extremity of the aperture to the other. The lip of the columella, or pillar, instead of turning inward, turns outwards ; that part which is covered by the inner lip being straight ; while the sinus, or notch, at the base, is even wider than in Melanopsis, to which this type obviously leads. But before we cross the threshold thus opened to us, we must notice Melanella, — another type resembling Hemisinus in shape, but having the aperture perfectly entire ; the inner lip is much developed, and its upper angle has a callosity precisely like that of Planaxis. So remarkably, indeed, does one of these Melanellce re- * Gray, in Griff. Cuv. pi. 13. fig. 4, CHAP. VII. MELANIA. - THE SUB-GENERA. 201 semble the Planaxis mollis in size, shape, and colour *, that none but a keen-eyed naturalist would know at first which was which. Both are of the same size and shape — both are white — and both are covered with a pale fawn- coloured epidermis ; the only difference between them being the presence or absence of the minute notch at the base of the pillar. We thus find the sub-genera of Melania not merely to form a circle, but to represent, in no unintelligible manner, the chief genera of the sub-family. Analogies of the Sub-genera of MELANIA. Sub-genera of Genera of the Melania Analogical Characters. Melacantha. Spire remarkably short. PALUDOMUS. Melania. Spire persistent, acute. Typical. MELANIA. r Body-whorl veniricose; spireT Hemisinus. \ long ; base with a wide but not > CERITHIDEA. C a deep notch. 3 TW / „//„ f Inner lip thickened above; spire > p .„._.„ £ short or moderate, pointed. j These remarkable analogies result from the breaking up of the old genus Melania; and this is the best apology, if any were needed, that we can make for so many new divisions. (186.) The next genus, MELANOPSIS, is no less diver- sified in its minor types, so that we may detect all those which, under a different modification, exist in the last genus. We enter this group by Melafusus — a name by which we designate a remarkable fluviatile shell, having the shape of a Fusus blended with that of a Melania ; it differs from Hemisinus in having the base more pro- duced, while the spire is shorter. Following this ap- pears the typical sub-genus Melania, — at once recognised by its acutely pointed spire being longer than the aper- ture, the thick enamel at the top of the inner lip, and the inward curve of the pillar : the manner in which the whorls are disposed on this and the next sub- * Sowerby's Genera, art. Planaxis, fig. 2. 202 SHELLS AND SHELL-FISH. PART I. genus deserves attention ; they are so far imbricate that one overlaps the other to full one half of their length, so that the suture of the basal whorl extends half way up that which precedes it, and gives the ap- pearance of the outer lip ascending on the spire. But among the fossils figured by De Ferussac, there are some which have an aspect altogether different: the spire, instead of being acutely pointed, is obtuse, and so short as to consist of only three whorls ; the aperture is also represented as much shorter than in any of the recent species, and the base more effuse. Again, there are two species*, which perfectly resemble the sub-genera Me- lacantha and Hemimitra, being short, broad, and coro- nated with a single row of short spines, — the tip of the spire being acute. Now, as these two types obviously accord with Potadoma and Melacantha in the adjoin- ing circle of the Melanice, we have not scrupled to designate them as sub-genera, — distinguishing the first as Melanithes, as being yet only known in a fossil state, and the second as Canthidomus, from its little spines. The confidence we repose in the accuracy of Ferussac's beautiful but costly plates, induces us to do this without having ourselves seen any of these shells : but the cha- racters we have stated cannot be doubted ; and the links by which these two presumed types are connected with the recent sub-genus Melanopsis are so perfect, that they have every indication of being natural sub-genera. t We must now notice a fifth type, which unites something of the characters of those two very opposite sub-genera, Canthidomus and Melafasus; this is our sub-genus Melatoma, founded upon a remarkable Ohio shell sent us many years ago by our old friend professor Rafinesque. It has the general form of a Pleurotoma and of Mela- fusus, with a well-defined sinus or cleft near the top of the outer lip ; while the inner, though thin, is somewhat * Plate Melanopsidce, fig. 16. 7. Plate 2. figs. 9, 10. t Thus the species at pi. 2. fig. 12. plainly connects Melanithes with Can- thidomus ; while those on pi. 1. fig. 14, 15. seem to be aberrant to the last sub-genus, leading to the long-spired Cerithidlce. Fig. 6. pi. 2. is clearly a Pirena, and fig. 8. a Cerithium. CH. VII. SUB- GENERA OP MEL ANOPSIS. - ANALOGIES. 203 thickened above ; the pillar is straight, and the notch at the base nearly as wide as that of an ordinary Pleu- rotoma ; the whole shell is marked with regular longi- tudinal plaits, and coronated on the suture by a row of tubercles. Our specimen, although in bad condition, is still partially covered with a brown epidermis, beneath which the shell is of a livid colour : the aberrant species of Canthidomus, as C. costatus and Owenii, pass into Melatoma, and complete the circle. Analogies of the Sub-genera of MELANOPSIS. Analogical Characters. Sub-genera of Melanopsis. Melafusus. Melanopsis. Baseof the aperture contracted. Potadoma. Melanithes. Tip of the spire obtuse. Melania. Sub-genera Genera of of the Melania. MELANIAN.K. MELANOPSIS. MELANIA. "" "] The use of the last, or additional column, which con- tains the genera of the entire sub-family, is chiefly for the purpose of showing that Melatoma, while it preserves its analogy to Pleurotoma, agrees also with Planaxis in having the base notched, and with Mela- nella by its thickened inner lip. (187.) The next genus is' that of Cerithidea. We have now come to the cyclostiform type, which, with the elongate form of Scalaria, has an effuse and circular aperture, with the outer lip dilated into a broad fringe, and a very short notch at the base. The lightness of these shells would seem to indicate that they were flu- viatile ; but as they are slightly variegated, and have no epidermis, we should not be surprised at their being found in the sea, — more particularly as this appears to be the point where the series of fluviatile Testacea terminates, and the marine commences. Nevertheless, the great change from Melanopsis to Cerithidea is not SHELLS AND SHELL-FISH. PART I. sudden ; for it is here we shall insert,, as an intervening form, our sub-genus Ceriphasia (fig. 38.), founded upon certain Ohio shells resembling Ce- rithidea, but whose outer lip is thin and sharp. Unfortunately, we can find no account of the animal, nor are we acquainted with any shells which will connect these with Me- lanopsis on one side, and with Ce- rithidea on the other. Until our path, therefore, is better marked, we must leave their precise situation as doubtful. There are evidently three or four sub-genera un- discovered or uncharacterised, which belong to this genus. One of these, we suspect, will be found in certain small species, figured as Melanopsides by M. Ferussac : their spire is unusually lengthened ; and the whorls are strongly and longitudinally plaited. As our last genus, we introduce Planaxis, — the animal of which, having been fully investigated and de- scribed by M. Quoy, proves that their shell must be arranged with the Melaniance. It is difficult to conceive why this eminent malacologist should have introduced it near to Buccinum, when he expressly says that in the structure of the animal it comes close to Melania. If Planaxis was to be arranged from its shell alone, it should be placed next to the Purpurince, since it has the pillar-lip very broad and flattened ; it is, in fact, a Purpura among the Melaniance, and, like them, the eyes of the animal are placed on short peduncles, close to the base of its two long and slender tentacula. Some of these, like the common species, P. subsulcata, has a very short spire; but another, the P. decottata, dis- covered by M. Quoy, has the spire of a Melania, while its name seems to imply that the terminal whorls are deciduous. (188.) Having now, as far as possible, analysed this sub-family, a few general remarks may follow. The Melaniance may be viewed as that group of the Tur- CHAP. VII. MELANIAN^E. GENERAL REMARKS. 205 bidte which stand upon the very confines of the phyto- phagous circle, yet still within its limits : it therefore partakes much more of the tribe which Nature is about to enter upon, than of that she is on the point of quitting ; and, consequently, not only the animal, but even the shell, is so fashioned as to exhibit this preponderance to the first rather than to the last group. On this broad principle do we account for the indication of a basal channel seen in all the sub-genera of Melanopsis, in Pla- naxis, and in Cerithidea. Nay, to such a refined point is this principle of gradual developement carried, that we hardly know, at present, where to draw a line of demarcation between the Turbidte and the Strombidce; not, of course, in their pre-eminent types, but in those which are aberrant. Cerithium is in one, and Ceri- thidea in the other. Their typical forms are easily dis- tinguished. But in which of these are we to place the apparently anomalous sub-genus Ceriphasia ? and how delicate and refined are the characters by which this is proposed to be detached from the fluviatile Potoniidts of Brongniart ! It is here, then, rather than among any other of the Melaniance, that we should say the two tribes actually unite. All modern writers, indeed, have perceived this ; and some have gone so far as to unite all the sub-genera of Melania and Melanopsis, and many of the Cerithince, into one genus. It is quite clear, however, that if this principle be acted upon, the greater our knowledge of the Testacea is enlarged, the more must the number of our genera or divisions — call them what we will — be reduced. New species bring new modifications of forms ; and these, filling up inter- vals, and softening down differences, will so blend groups which are now in some degree detached, that the whole, in process of time, will present but one continued chain of gentle gradations. No " well-marked divisions," in the sense which the term has been used in, could by any possibility exist. Our tribes and families, genera and sub-genera, would melt, one after the other, into the general mass — they would be abolished — and our 206 SHELLS AND SHELL-PISH. PART I. divisions would be species, and species only. We may be pardoned, perhaps, for alluding to this great error in our nomenclature more than once, because it appears to us to be fraught with more inconveniences — not to say evils — than those of an opposite nature ; and because, in the group now before us, we have been obliged to name and define so many new divisions. These divisions, in fact, will show more forcibly than any general argu- ments, the perfect confusion in which we must have exhibited this portion of the Testacea,if we had left them under the three or four genera where they now stand in the latest systems of conchology. (189.) That the Turbines follow the Melaniance is evident from the close connection of Cerithidea Sw. with Scalaria Lam. : the little basal channel of the former gradually lessens in the aberrant species, until, in one we possess from Florida, it is a mere vestige. This affinity fixes the station of the sub-family before us better than all theoretical reasons. The Turbince are all marine shells, and possess a perfectly entire aperture. Their typical genus, Turritella, is subulate, or awl-shaped, so as to have the spire very long. All the Turbince have their aper- ture closed "by an operculum, and their substance is never perlaceous. From overlooking this very obvious differ- ence, even in the shells, all conchologists, excepting Hum- phrey, have blended them with the Trochidce. Cuvier, at least, from the knowledge he had of the difference of the animals, should have not fallen into this error : the con- fusion has been still further increased by M. Ferussac ; for he has given to the Turbines of Humphrey the new name ofLittorina, and transfers that of Turbo* to Humphrey's Senectus. We do not usually trouble the reader with these misnomers, but we shall correct them as they occur. Our genus Turbo, therefore, is that of Linnaeus and Hum- phrey, the last of whom we also follow in placing all the perlaceous ones in that of Senectus. There are so few variations or sub- genera in the TURBINE, that we shall * The common winkle, Turbo littoreus Linn., is the type. CHAP. VII. GENERA OF THE TURBINE. 20? here chiefly confine our notices to the five leading genera : these appear to be Scalaria Lam., Turritella Lam., Turbo Humph., Melampus Mont., and Scissurella D'Orbigny. (190.) The genus Scalaria, as the circular-mouthed group, represents Cyclostoma : the typical form seen in the common wentletrap (S. pretiosa Lam.) has no pillar, although it is a long spiral shell. These lead obviously to Turritella,vf]\ere the shell is even more attenuated, so that the whorls are fully as numerous as in Tercbra, which it thus represents. Turbo (pukhra, fig. 3tQ.) is the next genus, differing chiefly, as regards the shell, 30 xJlb\ *n tne mner lip being broad and flat- tened, and the spire often very short, or not longer than the aperture. There is certainly a resemblance be- tween many of these shells and the more globose Trochidce, particularly the sub-genera Pagodella and Echi- nella, which are not perlaceous ; but the great thickness and depression of the pillar in Turbo, its perfectly round aperture, and the convexity of the body-whorl, are sure marks of dis- tinction. In the invaluable plates of M. Quoy, there is a figure of the animal of a species of Turbo (under the name of Littorina), which shows it to have almost a zoophagous structure, — so totally different indeed from that of Trochus, that they have even no analogy to each other. • The same may be said of Phasianella, which is only a long-spired Trochus, analogous, indeed, to Tur- ritella, but with the short mouth and lateral filaments of the Trochidce. (191.) The next genus, Melampus Montf., is one of particular interest. It was originally proposed by Lamarck ; but upon being told that they were land shells, he aban- doned his name ofConovulus, and incorporated the species in his genus Auricula. This was clearly a retrograde movement ; for, even had his information been correct, the difference of these two genera on one hand, and the close resemblance between Tornatella and Melampus, is too ob- 208 SHELLS AND SHELL-FISH. PART I. vious to be overlooked. From the MS. notes of Guildixg, it appears that these little shells are not more terrestrial than the other marine Turbines. In regard to amphibious Testacea, or such as live both in and out of water,, the following valuable remarks are taken from the Guilding MSS. " The genus Melampus commonly inhabits the shallow parts of the coasts, but I have received Melampus coniformis ? from stagnant fresh waters on the shores of Tortola, which only communicate with the sea occasion- ally during heavy rains, when the accumulated water is discharged with it. They are found creeping on the mangrove roots; and, like manyof the Neritida and Tur~ binidce, are perfectly amphibious, and very tenacious of life. The latter, indeed, though they descend to feed at night, are often seen on the trees of the coasts, and on the dark black rocks elevated above the surface at high water; they remain stationary on the latter during the hottest hours, even when it is painful to walk on them from their great heat. The difference of the waters inhabited by testaceous Mottusca does not, as was once supposed, offer a certain guide for the division of genera. Many of the Neritince, for instance, dwell in the fresh waters of rivers, while I have dredged up others in the bays and shallows of the ocean." * ( 1 92.) This genus, as far as we can at present judge, seems to be composed of the following groups : — Geo- vula Sw., Melampus Montf., Rhodostoma Sw., Pedipes Adanson, and Scarabus Montf. All these are clearly separated from the sub-genera of Turbo by the total want of an operculum ; while from Auricula they are still further removed by the branchia being pectinated, by having two tentacula, with the eyes at the base, or sessile, and in the shells being more solid. The highly interesting and valuable essay by Mr. Lowe on Pedipes and Melampus t, satisfactorily proves that these cannot belong to the Pulmonaria of Cuvier, and are therefore excluded from the land shells, or Helicidce. But whether the genera Geovula and Scarabus have their , * Guilding's MSS. f Zool. Journ No. xix. p. 281. CHAP. VII. MELAMPUS. — SCISSURELLA. 209 branchia also pectiniform, we have no means of knowing. The aspect of their shells, however, induces me to place them for the present in the same group, more especially since we have already shown they would altogether dis- turb what we think is the natural series of Auricula and Clausilia. We do not attach any importance to the fact of Geovula having an epidermis, because, although the excellent zoologist just named thought otherwise, we possess several specimens of a typical West Indian Me- lampus, where a thin brown epidermis is over the whole shell ; and this also is common to the sub-genus Rhodo- stoma. The peculiar depression of the numerous whorls of the spire in Geovula, Scarabus, Melampus, and Rho- dostoma, strikingly contrasts again with the few and produced volutions of the true Auricula ; and the whole are separated from Tornatella, by the animal of the latter having an operculum, and being differently formed. Tor- natella, in fact, seems to represent the sub-genus Me- lampus ; while Truncatella of Lowe, probably, does the same in the circle of Turritella. The whole of this sub-family, however, requires much more attention than we have yet been able to give it. (193.) We place the genus Scissurella as the only type of our last division, from a belief that it is analogous to lanthina. It was first characterised by M. D'Orbigny, one of the most eminent naturalists of France, who found his specimens among sea sand. It is very minute, and the animal is unknown : its general shape is that of Si- garetus or Vitrina, but there is the same sort of long narrow slit in the outer lip as is seen in the Pleuroto- mincB, in Pleurotomaria, and in lanthina; thus we have numerous analogies, while in affinity we consider this genus to be the pateUiform type of the Turbines. The very beautiful figures in Mr. Sowerby's Genera, is all we yet know of Scissurella; but we possess two or three similar shaped shells, which appear closely connected to this type, and probably enter into the same genus. (194.) We shall now take a rapid view of the five genera which appear to compose the sub-family before us. 210 SHELLS AND SHELL-PISH. PART I. These and their analogies may be arranged in the fol- lowing table : — Genera of the TURBINJE. TURRITELLA. SCALARIA. SdSSUR^A. MELAMPOS. Analogies of the TURBINE. Sub-families Analogies. of the TURBID.E. "SESs&si ">n8cr] *«»"- Spire excessively long. MELANIAN^E. Mouth circular, margined. TURBINE. Genera of the MELANIAN.K. Melania. Cerithidea. Palndomus. We introduce two series of analogies in this table, because one will better illustrate what may be thought obscure in the other. The two first set of analogies, Turbo and Turritella, are particularly strong; for we thus find the needle-like Melaniance represented by Turritella,' and Turbo by Ampullaria, both equally ventricose and turbinate. The thick or margined aperture, again, of Scalaria and Cerithidea exist in no other groups. It must be remembered, also, that the Turbida, as a family, is the cyclostiform or circular-mouthed group of the phytophagous tribe ; and this character runs through the whole group, with the exception of Melampus : Sets. surella and lanthina have the strongest analogy ; and these, with Planaxis, have the most effuse apertures of all their congeners. We must confess, indeed, that, but for the discovery of Scissurella, we had long imagined that Planaxis formed the most aberrant genus of the TurbincB. The last set of analogies is those between Melampus, Thallicera, and Paludomus :. it is not very strong ; yet, as they are the only shells with plaits on the pillar, they represent the volutes and the land Auri- cula; while it seems that Mr. Say has discovered an Anculosa, whose pillar bears a plate or fold precisely analogous to that in Thallicera. (195.) Of the next sub-family, represented by the beautiful and delicate lanthince, or oceanic snails, little CHAP. VII. TURBINE. TROCHID^E. 211 can be said. The only two genera we can venture to place in it are lanthina of Lamarck and Trichopodus of Sowerby. The first consists of those pretty but fragile violet and white snails which so much resemble the He- licidfB : the animal has been described by Cuvier, and is so very peculiar, that it cannot be arranged in any of the foregoing divisions, and yet it occupies that place in the Regne Animal precisely where we should have placed it, — that is, immediately after Melampus. "Theanimal," observes Cuvier*, "has no operculum; but the under sur- face of its foot is furnished with a vesicular organ, resem- bling a bubble of foam, but composed of a solid substance, which prevents the animal from crawling, yet allows it to float on the surface of the water. The head, a cylin- drical proboscis, terminated by a vertically cleft mouth, and armed with little hooks, has a bifurcated tentaculum on each side." Nothing, unluckily, is here said of the position of the eyes; but it is sufficiently clear from this short account, and also from the shell, that the lanthince belong to the family before us. We follow Lesson in placing the singular genus Trichopodus as intermediate between this and the last division, yet coming much nearer to lanthina than to Turbo. This brings us to the end of the series ; and if, as we believe, Thallicera stands between lanthina and Ampullaria, we reach again the point from whence we commenced our survey, and thus complete the entire circle of the TurbidtB. (196.) The TROCHID.E, as a family, are distin- guished from all the phytophagous Testacea, both by their animals and their shells ; although much more by the former than by the latter. The invaluable re- searches prosecuted by the French voyagers, more es- pecially by MM. Quoy and Gaimard, joined to the scattered notices in other authors, have so far afforded information on the animals of the TROCHID^:, as to detach them from the Turbidce, with which concho- logists have hitherto mixed them. The following * Griff. Cuv. xii. 63. p 2 212 SHELLS AND SHELL-FISH. PART I. analysis may, therefore, be interesting, as the most perfect we have heen able to lay before the reader. (197-) The animals of the present family widely differ, both in habits, shape, and anatomy, from those inhabiting the Turbidae. In the first place, their mouth is more like that of the slugs and snails (Helicidce), being composed of two short lips, — the upper, and some- times the under, of which is cleft and fringed ; the eyes, instead of being supported, as in the TurUdce, half way on the tentacula, are seated on two short but very thick tubercles ; while the long and slender tentacula are nearly cylindrical, and of equal breadth throughout : the whole structure, in short, is intermediate between the animals of the ear-shells (Haliotidce) and the snails (JJeHtiflte) ; further, the generality have three long slender filaments on each side of the foot, as long as the tentacula, but the use of which is unknown. In one of the topical groups, and in Phasianella, the aperture is closed by a strong, and often very thick, shelly operculum ; but in the Trochidce, this covering is horny, except in that particular group which con- nects them with the Senectince : in the Rotellinte, again, the operculum is horny. (198.) The shells, in their typical examples, may in general be recognised both by their pyramidical shape, and by their substance being perlaceous, — a fact always indicated by the rich pearly hue of the aperture. As this is the most prevalent, it is perhaps the best cha- racter for the mere conchologist to go by : and yet this will not serve in all cases, because the pheasant-snails (Phasianella Lam.) and the carriers (Onustus Hump.) are not pearly ; and even the most aberrant sub-genera in Senectus, Trochus, and Monodonta, which represent the carriers, are equally destitute of this substance. Nevertheless, all these, excepting the first, have their basal whorl so much depressed or flattened, and their shape so trochiform, that a little attention will soon make the student familiar with them. (199.) We think the following groups are the pri- CHAP. VH. TBOCHID^E. PRIMARY DIVISIONS. 213 mary divisions, and hold the rank of sub-families: — 1. The PHASIANELLIN^J, Lam., where the shell is spiral and obovate, and shaped like a Bulimus ; the outside is polished, and the operculum shelly. 2. The SENECTIN^E*, or sea snails, resembling the garden snail in form, but perlaceous, and furnished with a thick, round, shelly operculum. 3. The TROCHIN^J, or tro- chuses, having the shape more pyramidical, the body- whorl flattened, and the aperture closed by a horny operculum. 4. The ROTELLIN^, or wheel-shells, which are also perlaceous, and nearly discoid in shape, with a thickened mass over the inner lip. 5. PLEURO- TOMARIA Def., — a fossil trochiform shell, having a slit on the outer lip, as in the genus Pleurotoma of Lamarck. Such are the primary forms, which seem to belong to the TROCHID^:. Our information on the animals is partial ; but there is enough to guide us in three of the chief groups. Thus the ques- tion whether PhasianeUa belongs to this family, or the TurbidfB has been set at rest by M. Quoy, among whose beautiful figures is the animal of the typical species : the same eminent zoologist has also decided the relations of Senectus to the TrochintB, by figuring the Turbo sarmaticus, — thus showing its affinity to the animal of Trochus. The gradual chain of con- nection between Trochus, Solarium, and Rotella, leaves us in no doubt that these also form part of the family ; but whether Pleurotomaria is merely a genus of the latter group, or the representative of a sub-family, must still remain a disputed point. We insert it, how- ever, under the latter supposition, because it will appear by the following analysis, that it can in no wise be in- corporated elsewhere. (200.) The PHASIANELLIN^, or pheasant-snails, form one of the most isolated genera in the whole of the Testacea. That they represent the Turbidce, is obvious; for Lamarck and his followers have mixed * Senectus of Humphrey, Marmarostama (pars) Sw., Turba of Cu. vier, &c. p 3 214 SHELLS AND SHELL-FISH. PART I. them together. Their exterior is the most beautiful of all the Trochidce, not merely by the richness and end- less variety of their colours, but from their exterior being almost as highly polished as the olives. The mouth has two cleft and crenated lips ; the tentacula are long, slender, and of equal thickness throughout, while on each side of the body are three lengthened filaments. The Phasianellce are nearly all natives of the Pacific Ocean, and have an oval-shaped operculum. One species, of a small size, is found in Britain. This is obviously the long-spired group of the Trochidce, re- presenting in this family the Turbidce, the Buccinidce (wherein is Terebra), and the Cerithince. (201.) The SENECTIN^I, or snake-shells, were sepa- rated by Humphrey from the Linnsean genus Turbo near forty years ago ; but conchologists have continued, up to this day, to confound the two, or, rather, to mis- apply their names. This most natural group contains nearly all the largest and the most splendid shells of the family, — all of which we believe, possess a circular and very strong stony operculum.* The body-whorl is always ventricose, and is not depressed, like that of the Trochince ; it is produced at its base, in the typical examples, into an obtuse lobe, analogous to the prolong- ation of the base of the zoophagous gastropods, yet without any channel. Thus we perceive, at every step, how completely Nature preserves her uniform principles of representation ; for it is clear that these Senectince represent the zoophagous or channeled tribe, just as Trochus represents the Phytophaga. The snake-shells form themselves into very natural genera. The first, to which we retain the sub-family name of Senectus, is known by the spire, although small and short, being always ventricose and pointed, the body-whorl very large, the base produced into a lobe, and the umbilicus altogether wanting. The most gigantic, elegant, and magnificent shells of the whole family enter into this group, which are chiefly natives of the southern hemi- * Excepting, perhaps, that type which corresponds to Onustus Humph. CHAP. VII. TROCHID.E, SENECTIN^. 215 sphere. The ventricose form of the body-whorl of, course, modifies the shape of the aperture, which is thus always circular, and but seldom oblique. Before we had sufficiently studied this family, we included the foregoing in our genus Marmarostoma ; but we intend to limit that name to the umbilicated division of Hum- phrey's Senectus, represented by the M. versicolor*, — the passage from one to the other group being made by our Senectus coronatus.^ The umbilicus in these is, indeed, small, but very deep ; the spire is almost perfectly flattened, the tip obtuse, and the base even more pro- duced than in Senectus. It is quite clear to us, that more than one species is confounded by conchologists under the specific name of coronatus; since some have an umbilicus, and others not. In all the Marmaro- stonifB, however, the pillar is present ; but on entering upon Lamarck's Delphinula, the umbilicus is open to the terminal spiral whorl, and there is no pillar : the Turbo torquatus of the old conchologists is, therefore, a true Delphinula, connecting this genus with the last. Of the fossil shells referred to Delphinula we shall not speak ; judging from their figures, and from a few speci- mens we possess, they appear to require a thorough revision, and to contain types very different from those which are recent. Our next genus, if it be really one, contains, at present, but two species, differing in being very slightly perlaceous : they may be compared to Delphinula without an umbilicus. The name of Cyclo- cantha may explain their round form, and the circle of spines on the body-whorl. Cidaris is the last genus, and contains those Senecti which have the base desti- tute of any lobe, the aperture more oblique, the apex of the spire obtuse, and the outer surface almost always smooth J; the aperture is quite circular, and closed by a thick calcareous operculum. There are many species, of which the beautiful Cidaris sarmaticus may be * Turbo versicolor Martini, pi. 176 fie. 1740, 1741. t Ency. Meth. 448. fig. 2. J Except in our S. coronata, which connects this sub-family with the next, P 4 216 SHELLS AND SHELL- FISH. PARTI. selected as the most typical. By simply following the line of affinity, we thus return to our first genus, S&- nectus; for it is easy to perceive that Cidaris pethiolatus has the spire and general aspect of Senectus, with the truncated base and smooth surface of Cidaris. The circle, in short, is complete. (202.) The TBOCHIN^E naturally follows the last division. The body-whorl, which in the snake-shells is ventricose, is here depressed, and often flattened beneath; and this modifies the aperture, which thus becomes broader than it is high, or transversely oval. It is by these latter characters, also, that the Trochidce are separated from the Turbida, where the aperture is invariably either round or longitudinally oval. In the last genus of the Senevtince, nature has begun to indicate the change from a round to a transverse aperture. The operculum of all • the more typical forms of the Trochidce is horny; but this change is effected gradually. The first genus, consequently, of the Trochince combines the characters of both sub- families. Canthorbis, in fact, has the depressed aper- ture of the Trochince, with the shelly operculum of the SenectincB. Canthorbis is a remarkably diversified group : it contains the largest of the Trochi, properly so called, as distinguished from Senectus ; but in all the shell is nighly perlaceous, the aperture transversely oval, and the operculum shelly.* The five types of form, or sub- genera, are all recent ; and as their characters will subsequently be given, we shall only, in this place, il- lustrate them by general observations. All the large, spinous, nodulous, and long-spired Trochi belong to this genus, in which there are very few having a smooth surface. It is connected to Cidaris by Rugosus and Cookii; to Onustus by the sun-shells j and to the typical Trochi by our sub-genus Carinidea, into which, as we suspect, will enter the Trochus Niloticus of Linnaeus, — * If, as Sowerby mentions, the operculum of the Trochus Nt'lolicus is horny, instead of shelly, it will be the osculant species connecting Can- thorbis to our genus Trochus. CHAP. VII. TROCHIN^. THE GENERA. 21? a very remarkable shell : out of hundreds, we have never yet seen a specimen, however large, which had a perfectly formed mouth, so that we feel somewhat un- decided as to its precise station. In a young state, the basal volution is often perfectly flat, and even concave ; and this gives the margin precisely the same carinated edge as belongs to Carinidea ; but when more advanced it becomes convex, as in the genuine Trochi, — thus uniting, at different periods of its growth, the characters of the two groups between which it appears to stand. (203.) Having now shown, by the foregoing details, the union of the Senectinte and the Trochince, we shall briefly characterise the remaining genera of the sub-family we are now upon, and then notice their sub- genera. Canthorbis has already been defined : following this is Trochus, properly so called, where the umbil- icus, if it exists, is never toothed, and very rarely channeled. In Monodonta, these characters are reversed; the umbilicus, if present, is always either toothed or channeled, and the aperture striated. The fourth genus is Solarium, where the umbilicus is so large as to reach to the apex, the pillar is absent, the shell nearly dis- coid, and the aperture without any defined lip. The last genus is Onustus, long ago separated by Humphrey, to include those singular and half-formed shells, called by collectors,, Carriers. Of the animals by which these are formed, we as yet know nothing ; but their shells are composed partly of the usual calcareous substance, and partly of little stones or fragments of other shells, which the animal gathers up and incorporates on the outer surface -of its own habitation. A gradual series of intervening forms unites this group on one hand to Solarium, and on the other to Canthorbis ; so that the whole of the Trochince, being united into one circle, constitute a natural and perfect group. We shall now notice each of these genera in detail. (204.) Having already spoken of CANTHORBIS, we pass to the second genus, TROCHUS. Were we to make this an artificial group, its definition would be very 218 SHELLS AND SHELL-FISH. PART I. easy, for it might then be formed to contain all those small or moderately sized trochuses, which are without a distinct tooth at the end of the pillar, and have a horny operculum. But this definition would break up the natural series. The group, in fact, is so difficult to cha- racterise in general terms, that we suspect its funda- mental difference from that of Monodonta lies in certain peculiarities of the animals, with which at present we are unacquainted ; but if, to the foregoing characters of Trochus, we add that one of its sub-genera has a promi- nent tooth, but no umbilicus, and that another is not per- laceous, we shall then name the only exceptions. The whole genus, then, divides itself into the following five sub-genera: — 1. Chlorostoma,vf}\ere the basal volution is either perfectly flat or concave, the margin carinated, and the outer lip so oblique that it extends half way round the circumference of the shell ; the umbilicus is very deep, and is bordered on one side by the inner lip, which is suddenly truncate as soon as it reaches half way round the umbilicus : this leads to Trochus, or the typical sub-genus. All our British species, excepting T. zizyphinus, come into this division ; the umbilicus is more or less deep, and the aperture either entire or with a very slight angle at the pillar : by degrees, however, this angle is so much developed, that it assumes the appearance of a tooth : thus we are led into the sub- genus Trochidon, nearly all of which are natives of the southern hemisphere. Some have the tooth as distinct as in Monodonta ; but they may at once be known by having no umbilicus, even although the inner lip may have a slight marginal groove. But here, as nature has reached the highest point of developement, she again re- cedes ; the spire gradually lengthens, the tooth becomes a simple angle, and we enter on the smooth division of the group, forming our sub-gemis Calliostoma. The Trochus zizyphinus of British writers will give a very good idea of these shells ; they are nearly all either per- fectly smooth or slightly granulated, of a light and ele- gant form, a long and pointed spire, and no umbilicus : CHAP. VII. MONODONTA. THE SUB-GENERA. 219 several species, but little known *, are found in the Medi- terranean ; and these are the most trochiform, — that is, the basal whorl is unusually flattened, which renders the aperture narrow : those from the Pacific, on the contrary, are more ventricose, — thus representing Cidaris and the Senectince. This modification of form is to constitute the passage which here takes place between the five types of Trochus and those of Monodonta. The last sub-genus, Pagodella, is the only one containing shells that are not perlaceous. The student, at first sight, would think this was a most heterogenous group, for it contains species of very different forms: some are so like European Callio- stomfe, that they might be strictly arranged as such, if the substance of their shell was not regarded ; others are equally conic, but instead of being smooth, are beset with nodulous granules ; while others, again, are formed precisely the same as our first type, Chlorostoma, but yet have no umbilicus. But this is at once explained by the situation of Pagodella, which is intermediate between Cattiostoma and Chlorostoma. So exquisitely, also, has nature blended this genus with the last-named group, that there is one species, the Trochus Merula of La- marck, which unites in itself still more closely the cha- racters of Chlorostoma and Pagodella ; it has the shape, colour, and pearly substance of the first, and the flat- tened imperforate lip of the last ; it may, in fact, be called either a perlaceous Pagodella or an imperforate Chlorostoma. Having now gone through the genus Trochus, we proceed to the next, or sub-typical group. (205.) On entering the genus MONODONTA, we must refer to what has been just said on the Oceanic | spe- cies of Calliostoma, the greater convexity of whose basal whorl cannot fail to have been remarked; thus we are con- ducted to Elenchus, the first sub-genus of the present group, and found only in the same latitudes. These * It is of these, we believe, that the genus Margarita has been pro- posed, to include such as have " the operculum of few whorls." t The Continental naturalists employ this term to designate the pro. ductions of those countries or seas lying in the Great Pacific Ocean. 220 SHELLS AND SHELL-FISH. PART I. splendid shells, although mostly of a small size, have a brilliancy in the emerald green of their apertures, which is perfectly unrivalled in this family (figAO.) like the Callio- stomce, the basal whorl is convex, — more so, indeed, than 40 ' in any other of this se- nus, except that to which it leads ; the spire is also generally more produced, and in one species (a) is so long that it resembles a small Turritella. It is among these shells that the most prevalent character of Monodonta appears. The base of the pillar in some forms an angle, and in others a small but very distinct tooth : their exterior is always smooth.* Next to these we place a small group of equally ventricose shells, to which we retain Lamarck's name of Monodonta; they have, in fact, almost the form of Senecti, but they are small, and the pillar is both umbilicated and toothed : in some, these characters are very slightly developed ; in others, they are very strong ; and this variation takes place in species otherwise so much alike, that they might almost be taken for the same at different periods of growth. They are mostly finely granulated, and sometimes striated within ; but their ventricose aspect is altogether peculiar ; the umbilicus is always smooth round its edges, but varies in its size. In the next sub-genus, Fragella, the basal tooth is so large, that its projection, joined with the teeth on the inner margin of the outer lip, gives the aperture an appearance of being distorted. The well- known little shell called the strawberry trochus, is the type ; and, by its depressed form, pointed spire, and large umbilicus, reminds us immediately of a genuine Trofhus : the surface of nearly all is beautifully granu- lated. In our fourth group, or Monilea, the umbilicus and its singular marginal rim are precisely the same as in Chlorostoma, except that the umbilicus is wider, the * This beautiful group was well known to Humphrey, whose name, im- posed near forty years ago, we have of course retained, instead of some others recently given by the French nomenclators. CHAP. VII. SOLARIUM. ONUSTUS. 221 shape more depressed and trochiform, and the surface of the shell often granulated ; the only remnant of the tooth is shown by one or two small tubercles or notches at the base of the outer lip. Several species, mostly of a small size, are now before us, all of which are natives of warm climates or of the Pacific Ocean. Lastly, we find in this genus, as well as in TBOCHUS, one division which have not perlaceous shells, but which, possesses a well-defined tooth. These species we include under the name of Echinella. The most typical is that figured in the Ency. Meth. (pi. 417- fig- 6.) as Monodonta coro- naria, — a shell which is a perfect prototype of our Pa- godella echinata : the species yet known are few ; but of these we possess the connecting link to Eknchus, in our E. granulata. We are thus brought back to Elenchus* where we commenced our survey of MONODONTA. The naturalist will not fail to perceive, that in thus resting our arrangement upon affinity, we have indicated strong relations of analogy between TROCHUS and MONO- UONTA : to these we shall presently return. (206.) The two remaining genera, SOLARIUM and ONUSTUS, do not comprise more than a fewrecent species, although it is highly probable that many of the imper- fectly preserved fossil discoid shells belong to the first, and some few also appertain to the last. On receding from the typical species of Solarium, the spire becomes more prominent, and the edge of the body- whorl dilated to form a sharp edge, so thin as easily to be broken off ; the crenated margin of the umbilicus of these shells, how- ever, indicates their affinity to the singular genus Onustus. From certain slight and irregular indentations on the preliminary whoris of the spire, we suspect that, at an early age, many of these animals gather small fragments, and fasten them upon their shells ; but that, when older, these extraneous substances either fall off, or are volun- tarily discharged; just as if the animal, having acquired its full powers by age, was able to fabricate its own ha- bitation without calling in other assistance. Now, the same advance which we have thus stated as taking place 222 SHELLS AND SHELL-FISH. PART I. from Solarium to Onustus on one side, can also be dis- covered on the other side from Canthorbis. The gra- dation, in fact, is equally perfect on both sides : the two extremities of the column of the TROCHIN.E, com- mencing with the sub-umbilicated species of Canthorbis, and ending with the sharp-edged Onustus, meet to- gether in the Onustus agglutinans *, which thus closes the circle of the five genera of the TROCHIN^E. (207.) The two aberrant types of this family are as remarkable for the paucity of their forms, as the typi- cal TROCHIN^E are otherwise. Of the Rotellina;, in fact, we can only enumerate two genera ; and one of these not so effectually as we could wish. We think the Turbo Ni- cobaricus is the type of a sub-genus (Chrysostoma Sw.) much more related by its shell to Rotella than to Senectus, even if its operculum should prove to be shelly. It differs from ah1 other Trochidce, in having a very thick deposition of shelly matter spreading over the umbilicus, which it almost conceals : it does not, however, extend near so far as in Rotella; and yet both shells are evidently highly polished by their animals. On this account, therefore, and in the absence of all knowledge of the animal, we place it as the represent- ative, among the RotellincB, of Senectus and Monodonta. Of the fossil genus PLEUROTOMARIA very little can be said : it obviously enters into our present family, from the trochiform shape of its shell ; and the foregoing analysis renders its station in any other group highly improbable ; we place it, therefore, between Rotella and Phasianella, as the type of a sub-family, the other members of which cannot now be distinctly ascertained. The truth is, that in this and numerous other instances, the study of fossil conchology is impeded by insur- mountable difficulties, which must always exist. How many genera are in our systems, belonging to the older * It is somewhat remarkable, that, from Lamarck's description of this shell, it would seem to have the umbilicus open when young, but closed when it has reached maturity. In two fine specimens now on the table, it is completely covered ; arid yet there is a fossil species from Hordwell, where it is perfectly open, although not large. CHAP. VII. TROCHID.E. - TURBID^E. — ANALOGIES. 223 geological beds, which we only know from casts and mutilated fragments ! and how many others, even in the newer formations, which it is impossible to arrange with precision, from ignorance of the animal ! These are the true reasons which lead us to say as little as pos- sible upon all those fossil genera whose affinities are doubtful ; since, from the peculiar nature of the object we have in view, we would rather incur the imputation of overstrained caution, than the opposite extreme. (208.) We have hitherto considered only the affini- ties of the TrochidcB ; let us now turn to their analogies. Our first table will be of the primary divisions, or sub- families, which represent those of the Turbidce in the following manner : — Analogies of the Sub-families of the TROCHID.E and the Sub-families of Sub-families of the Trochida,. Analogical Characters. Turbida. Typical Genera. Typical Genera. . ('• Sub-typical.) SENECTUS. r (1. Sub-typical.) } -J Shell globose ; operculum shelly ; > AMPULLARIA. C spire short, obtuse, ventricose. j nu- C f (2. Typical.) TROCHOS. < Spire pointed; whorls more nu- J- MELANIA. C merous ; operculum horny. r (3. Aberrant.) } ROTELLA. 4 Shell depressed ; inner lip thick- >• THALLICERA. PHAS.ANELU. ** ; Oper- TURRITELI,A. Whatever may be the rank of Pleurotomaria, it is certainly the prototype of lanthina. These latter shells are so excessively brittle, that not one in five hundred are perfect ; but the sinus, although neither so long nor so narrow as in Pleurotomaria, is nevertheless fully de- veloped in the perfect shells, but more especially in our 7. globosa* The long-spined Turritellce represent Phasianella, and both have a shelly operculum. The other analogies are not so striking, — excepting, perhaps, * Zool. 111. 1st Series. 224 SHELLS AND SHELL-FISH. that of Senectus to Ampullaria; both being large globose shells, and the latter sometimes closed with a shelly operculum. The curious reader, who may be desirous of prosecuting these analogies further, may compare them, at his leisure, with many others in the volume. (209.) We shall now bring together the genera of the two sub-families. Analogies of the SENECTIN^J and the TBOCHINJE. Genera of the SENECTIN&;. SENECTUS. MARMAROSTOMA. DELPHINULA. CYCLOCANTHA ? CIDARIS. Analogical Characters. f Typical of their respective circles; 7 i volutions convex. 3 f Sub-typical ; umbilicus with a ba- 7 sal groove. 5 f Nearly discoid ; umbilicus very 7 i deep ; pillar none. 3 Shell not perlaceous ; trochiform. f Aperture oblique ; operculum 7 1 shelly. Genera of the TROCHIN.E. TROCHUS. MONODONTA. SCALARIA. ONUSTUS. CANTHORBIS. Our only doubt relates to what is the true type between Delphinula and Cidaris. It is either the shells we have before mentioned, or those of which Turbo pagodus is the type, where the operculum is horny. We may now turn to the Analogies of the Sub-genera of CANTHOBBIS. Sub-genera of CANTHORBIS. Tubicanthus. Canthorbis. Pyramided. Lamprostoma. Carinidea. Analogical Characters. f Aperture obliquely round or oval ; ? 1 smooth. 3 f Greatly depressed ; the sides ca- 7 1 rinated ; umbilicus small. 3 Aperture thin, sharp, brittle. ("Aperture strongly toothed ortu-7 I berculated ; striated within. J ("Aperture nearly entire, slightly 7 i angulated ; smooth within. 3 Genera of the TROCHIN.E. CANTHORBIS. ONUSTUS. SOLARIUM. MONODONTA. , TROCHUS. The results of this table will explain why we have thought it expedient to characterise as sub-genera the types of such a small group as Canthorbis; for the shells it contains are so remarkably varied, that, without some CHAP. VII. TROCHID.E. — CANTHORBTS. 225 clue to the meaning of this variation, it might appear a questionable group. The only one of these analogies on which we have any doubts, is that between Carini- dea and Trochus : we are, in fact, at a loss to know whether Trochus Niloticus and Turbo Pica are the real types of Carinidea, in which case they would open a passage from the large Canthorbi to the small and moderate-sized shells of our genus Trochus : the strong and unquestionable affinity, however, of Carinidea con- cavus* to our sub-genus Chlorostomus, although the one is a large and the other a small shell, cannot be disturbed. But, on the other hand, even if the passage from Canthorbis to Trochus is made by Niloticus and Pica, the difference is one of very inferior moment. Two things are certain : one, that Canthorbis is the intermediate group, which connects the Trochince to the Seneetince; the other, that it equally connects our genera Trochus and Onustus : for every conchologist will perceive that Tubicanthus runs into Cidaris by means of C. rugosus and Cookii. There is, however, another analogy belonging to Canthorbis, too remarkable to be passed over : it is, in its own group, what Cerithium is in the circle of the Strombidce: this is shown in its twisted and outwardly-curved pillar, as well as the numerous volutions, and the consequent length of the spire. According to this view, Pyramidea and Lam- prostoma would be the types, — since they are the most conical and elevated of all the others. (210.) We now come to the sub-genera of the two typical groups, Trochus and Monodonta. It has been seen that each forms a circular group ; and the pre- ceding observations will, in some measure, have pre- pared the reader for the following general exposition of their sub-genera. The genus Margarita of Leach appears to us a purely artificial group, partly composed of our umbilicated Trochi, and of the true Calliostomce ; we have therefore not adopted it. * Our specimen, fortunately, possesses its operculum, and has never been cleaned. 226 SHELLS AND SHELL-FISH. PART I. Analogies of the Sub-genera O/TROCHUS and MONODONTA, Sub-genera of TROCHUS. Analogical Characters Sub-genera of MONODON. Trochus. Trochidon. rallinstnmn. f More or less umbilioated, but the ? (_ umbilicus always smooth. j ("Base of the pillar (arming a pro- 7 1 minent tooth. J T Imperforate, smooth, or slightly") j granulated ; basal whorl some- f Monodonta. FrageUa. T?.70 Monilea. (_ half way round the margin. 3 These analogical resemblances are so close, that, but for the former explanations, an incautious conchologist might easily mistake one for the other. Unfortunately, we are in total ignorance of the animals of all these, Trochus excepted. Whether they have each a peculiar modification of form, or whether Nature has confined herself to tracing out these variations by the shells alone, are questions which time alone will develope. (211.) "A natural arrangement," as an eminent en- tomologist has more than once observed, " will stand any test." We have now placed it in the reader's power to act upon this hint, by applying all those " tests " which our preceding diagrams have supplied, to our arrange- ment of this family. There is one, however, which, from its singularity, may here be mentioned. Analogies of the TROCHID^E to the ACHATIN^E. Sub-families of TROCHID.E. SENECTlNjE. TROCHINJE. PLEUROTOMIN.K. PHASIANELLINJE. Analogical Characters. f Ventricose ; spire short ; aperture 7 ( always entire. 3 f Spire conic, more developed ; base 7 1 of the pillar notched or toothed. J Nearly discoid. C Outer lip, either above or below, 7 i with a slit. j Spire very much produced. Genera of the ACUATIN*. Bl'LlMUS. ACHATINA. CYCLOSTOMA. HELICINA. CLAUSILIA. CHAP. VII. TROCHIDvE. ACHATIN.E. 227 These analogies, of course, are much more remote than those we have heen tracing, because the groups themselves are much more remote; and yet the same mode of variation is preserved in two different families — one marine, the other terrestrial. The Rotellce in one, and the Cyclostomce in the other, are the most discoid shells in their respective families ; while, at the opposite side of the circle, we find the long-spired Phasianelke repre- senting the still longer-spired Clausilice. Some of the Helicina have a deep narrow slit at the hase of their aper- ture, precisely similar to that on the outer lip in Pleu- rotomaria ; and in both instances this structure is only a repetition of what is seen in lanthina, Scissurella, and Pleurotoma. The two first analogies equally hold good, so that the two groups mutually test each other. (212.) We have placed the Trochida next to the Helicida, under the belief that they followed each other, although the links of connection were wanting. It is clear, that of all the types of the TROCHID.E, Rotella is that which by its general form makes the nearest ap- proach to Helix ; while the thickening of the inner lip, which spreads over the umbilicus, is found also, but in a less degree, in many of the land volutes, Lucernincc. But a singular discovery, recently made, has thrown an entirely new light upon this interesting question. Among a considerable number of freshwater Planorbi, all of one species, which were sent us from Brazil, we picked out two helix-looking shells, so precisely of the same olive brown colour, and of the same size, as the others, that none but a conchologist would have been led to examine them. They appeared, in fact, like two little land- snails of the sub-genus Zonites, that had fallen into the water where the Planorbi had been found, — their outside being discoloured, and covered with little particles of dirt and sand. On placing them, however, under the magnifier, a conchologist can alone judge of our astonishment at finding that the whole of the shell was actually com- posed of little stones and grains of sand only, agglutinated together, yet with so much skill, by the animal, that the • ^ ^ } izi * **5 MACROTRACHIA. ATKACHIA. TUBULIBRANCHI . CHELISOMA. BRANCHIOPODA. • ..i a X u u «< 1 § § E i a Q 238 SHELLS AND SHELL-FISH, PART I. we know not, at present, the limits between the two. We could extend these analogies into the vertebrated animals ; for they are not only manifested among the reptiles by the Chelonides or turtles, but by the arma- dillos, in the order of ruminating quadrupeds, the Cas- sidce, or tortoise beetles, among the coleopterous insects ; and, in short, throughout the whole animal kingdom. (219.) Leaving, therefore, the true affinities of the Sigareti of authors undetermined, we may proceed to the genus Crepidula as the last we place in the present family. "We know not by what form, if any, it is con- nected to Chelinotus, but its affinity on one side to Na- vicella, and consequently to the nerits, has been long ad- mitted ; while to Haliotis it is as obviously connected by means of Crep. aculeata, and such other ear-shaped spe- cies as have defined spiral whorls placed on one side of the shell, as in the Haliotida. Hence it follows that Cre- pidula stands at one side of the circle of the Haliotidce, connecting them with the Naticida, and Calyptrtea at the other, connecting them with the Trochidce ; it follows, therefore, that they cannot be united by affinity, except indeed on our theory, that the three aberrant groups always form a circle of their own. (220.) Our fifth and last family is that of the Naticida, or nerits, consisting of those genera whose in- habitants are not furnished, like the Turbida, with a pro- boscis-formed mouth, and eyes placed upon their antennae, but whose mouth is like that of the generality of shell- fish belonging to this tribe, and whose eyes, where they exist, are at the base of their tentacula. The animal of one of the typical Naticida has been beautifully drawn by Guilding, and is here copied (fig. 43.) ; it is a most extraordinary looking creature. The whole family differs from the Trochidcs, moreover, in having no lateral fila- ments; and in the form of their lips, eyes, &c.; and from the Haliotida, in all that respects the animals, as well as their shell. For reasons, however, which we have just before this detailed, this is the only family whose analysis we find it impossible to complete : this originates in the CHAP. VIII. THE NATICID-ffi, OB NEBITS. 239 incertitude regarding the many earlike shells belonging or related to the genus Sigaretus of authors,, but of whose animals we know little or nothing. The reader will, therefore, understand that the only groups we consider to be natural in the following arrangement, are those of the Neritince and the Naticince; the three others being merely conjectural. If the animal of Cuvier's Sigaretus is like that of De Blainville's, we should thus refer it to the group which contains Chelinotus ; but we strongly suspect that the shells of the Sigareti figured by Sowerby* all belong to, and form the typical group of, the present family : Lamarck's Natica constitutes the second ; and the Linnsean nerits the third : the other two may pro- bably be represented by the Cryptostom C pie ior double. 3 Mantle free, and without a siphon. f Reciprocally representing the Ce- 7 i phalopoda. j f Body cheloniform, oval, covered} < with testaceous or coriaceous > C plates. 3 r Animal of the gastropod struc-T \ ture, furnished with an obtuse J- C head. 3 Tribes of the Gasteropoda. \ ZOOPHAGA. PHYTOPHAGA. TECTIBRANCHIA. CYCLOBRANCHIA. SCUTIBRANCHIA. This table is important, were it only to prove that the usual divisions of the more typical bivalves accord- ing to the 'number of their muscles, whether one or two, is not a natural arrangement ; because it destroys 256 SHELLS AND SHELL-FISH. PART 1. the beautiful analogy which is found to exist in the two typical tribes of the Dithyra and the Gasteropoda, and is not borne out by the details of their analysis. (240.) The MACROTRACHIA and the ATRACHIA com- prise by far the greater number, and the most perfect, of all the bivalves : and that they each form a circular group, will be apparent from the following consider- ations. The MACROTRACHIA may be said to have their first developement in the family of Pholida, — several of which, as Teredo, Clavagella, &c., assume the form of the Tubulibranchia. By means of Pholas and its sub-genera, there is a direct passage to the Myada through Solen : these semitubular shells are succeeded by Mya and Mactra, where all appearance of the gaping peculiarity of the Myadce ceases. We enter the Tellinidce by means of the river genera allied to Cyclas; and thus, through Venus, reach the Tellinae, where the two siphons of the animal are of enormous length. Cardissa Sw. and Pleurorynchus of Phillips open the passage to the CHAMID.E, where we see the siphons much reduced, and almost obsolete in Hippopus and Tridacna. The aberrant genera of Cardita and Chama unite with Cypricardia, and lead to the perfo- rating family of the SAXICAVID^B, into which also enter Petricola, Saxicava, Coralophaga, and Thracia. Finally, all these are as evidently connected to Gale- omma, as Galeomma is to Gastrochina. Thus we again arrive among the Pholadce, and the circle of the MACROTRACHIA is closed. (241.) The course of the ATRACHIA is precisely similar. Cuvier has already pointed out the connection of the ChamidcB to the Unionidce; while the genus Iridina in the latter, and Nucula in the ARCADE, show that the two families follow each other. The passage from these to the AVICULID.E is still more perfect,upon looking to the genera Byssoarca and Modiola: then follow Crenatula, Malleus, Avicula, and Pinna, which, uniting to Modiola, completes this group. Avicula opens the passage to the OSTREID.E, which are entered CHAP. X. MACROTRACHIA AND ATRACHIA. 257 by means of Lima and Pecten. Finally, in order to close this circle, we have the ETHERID^ which, with Mulleria, " is remarkable as a group possessing in itself both the character of being intermediate between Etheria and Ostrea, and as apparently connecting the regular freshwater bivalves with the regular marine bivalves, as Ostrea* The sinus at the posterior ex- tremity of the ligament of Mulleria resembles the Unionidce and the Etheria; while in its single mus- cular impression, as well as its general form, it ap- proaches to Ostrea" This obvious affinity at once closes the circle of the ATRACHIA, by the series re- turning to the Unionidce. The following table will consequently exhibit the mutual relations of both these tribes: — Analogies of the MACROTRACHIA and the ATRACHIA. Families of the tnainate,. Families of the Macrotrachue. Atrachia. TELLIMD*. MYAD.E. Valves gaping at one extremity. AVICULID.E. «„_. 5" Animals affixed to, or living with- 7 r. I in, other substances. j OSTREID*. SAXICAVID.E. Shells irregular, without teeth. ETHERID.S. r C" Lateral teeth long, linear, only on 7 TT J one side of the bosses. j &MIONIDJS. (242.) It will be seen, by the subsequent arrangement of the genera, that they follow each other precisely in the same way, so as to represent the families. To follow out this exposition, however, in the present tribe, as we have already done in that of the Gasteropoda, is manifestly impossible ; but, as we state this fact as the result of a careful analysis of the whole, the reader, knowing the general principle, may apply it to any particular group, whose analogies he wishes to trace. As we shall enter into a full investigation of the Unio- nida;, or river pearl-shells, our remaining space will • * Sowerby's Genera of Shells, art. Mulleria. 258 SHELLS AND SHELL-FISH. PART 1. barely be sufficient for a few general remarks on the other families ; and these will be confined to the forms most characteristic of the primary types of bivalves. (243.) The Tubulibranchia, or tubular tribe, may be traced in almost every one of the above families : it is shown by an unusual elongation of the shell, which is at the same time very narrow, a ad inclined to be cylindrical. The whole of the Solens have this analogy, as well as the genus Anatina, in the Myadce. Psammobia and Donax are modifications of the same ; and so also is Cardissa: most of these also have the anterior side remarkably short, precisely as in all the Pholadcs. Coralophaga is another example ; and it is even apparent in one of the sub-genera of Cardium. This type of form is equally, and even more strongly, developed in the order ATRACHIA : thus, we detect it in Iridina, Byssoarca, Lithophaga, and Avicula; all of which are the most elongated in general shape, and the most abbreviated at their anterior extremity. In an- other type, which evidently runs through the whole, it is characterised either by the absence of all teeth to the valves, or by there being but two, placed in the centre, and resembling the letter V reversed. This is almost always found in that division of a group which is most aberrant in its own circle, as the Saxicavidce and the Etheridce; the Anodontince among the river bivalves ; as well as the genera Pholadomya, Thracia, Acardo, Loripes, -Pinna, Placuna, Plicatula, Trigonia, Pan- dora, &c. A third type of form is evidently intended to represent the BRANCHIOPODA ; its chief distinction being that of having an internal cartilage — not, indeed, protruding through an opening in the valves, but situated between the cardinal teeth. This is well known to be the predominant characteristic of all the Mactridce, and of their prototypes scattered in other groups, as Gnathodon, Erycina, Nucula, Ungulina, Pecten, Pedum, &c. Now, it is a remarkable fact, that, on comparing our analysis of the whole of these circular groups, we almost invariably found that these three CHAP. X. UNIONID^ GENERALLY. 259 types always followed each other, and that they consti- tuted the aberrant divisions. On looking to the typical and the sub-typical divisions of the larger groups, we find that the first are the most perfectly closed bivalves, or the most highly finished and ornamented ; while the latter seem not to have so much the power of free motion, and usually gape a little at one extremity, — a sure sign that their inhabitants live in the ground, and do not roam from place to place. In the tribe of Macro- trachia, we thus have the pre-eminent type in the Tellinidte, and the sub-typical in the Myadce , the former being represented again by the Arcidce; and the latter by the Amculidae. We must, however, quit this inviting train of generalisations, and proceed at once to the only family of the Dithyra which stands in need of a more detailed examination. (244.) The UNIONIDJE, as before observed, are en- tirely fluviatile, and are the only river shell-fish in this tribe ; except indeed the Ether ince, by which they are connected to the marine oysters. As they form that particular family which unites the Atrachia to the Macrotrachia, we naturally supposed, that when they were better known, some trace of the siphons so cha- racteristic of the latter tribe would be found in one of the aberrant groups ; and in this expectation we have not been disappointed. M. Deshayes, it appears, has announced the fact, that the animal of Iridina pos- sesses these tubes ; and it further appears that the major part of the family, although really without these organs in a permanent state, have yet the power of forming two temporary tubes, with the posterior edge of the mantle, which is fringed with cilia, serving to deter- mine the direction of the water which flows into the branchia.* Thus, whether we regard the shell or its animal, we find that the natural station of the Unionid'^ (Unio ovatus of Say) 0^.49.); like Hyria, has the cardinal teeth as- suming the shape and the position of lateral teeth ; and both have merely two or three tu- bercles immediately be- neath the bosses. The elongated form of all the species of Mysca reminds us of Iridina, no less than the crenated edge and mar- ginaTdirection of the cardinal teeth. If Lymnadia, again, had no cardinal teeth, it would be a Dipsus of Leach ; and both these have the very aspect of Anodon. Mega- domus is the only type in which the lateral teeth are imperfect ; hence a truer prototype of Alasmodon, where both those teeth are entirely wanting, could scarcely be found; particularly as the cardinal teeth are precisely like those of the typical genus Unio. Our limits, and, indeed, our materials of specific nomen- clature *, will not permit us to analyse the whole of * The specific descriptions of Lamarck are scarcely less unsatisfactory than many of those recently published in America ; I have seen totally ANALOGIES. 267 these genera. Two, however, where the natural series appear to us very strikingly marked, will be now noticed : the first regards the sub-genera of our genus Unio, and the circular succession of the types of form in two of them. (252.) The genus UNIO, separated by its cardinal teeth from JE,GIAA, as already shown {fig. 47- &), contains five distinct types of form, which, from the multiplicity of species, and for the greater facility of nomenclature, we shall designate under the following sub-generic names: — 1. Unio: the bosses or umbones prominent and tumid, the circumference and the posterior hinge mar- gin never angulated, and both the cardinal teeth very much receding from the anterior margin, as in U. Mytilo'ides Raf., and all such species or varieties. 2. Cunicula, where the umbones are even larger, but not tumid, being, as it were, compressed or flattened : the shell is generally oval, or angulated at the base of the posterior side ; — examples, C. planulata, cuneata, purpurata, Lam., &c. : the outer cardinal tooth slightly diverges from the base of the inner. 3. Ligumia : the form is particularly long, like that of Iridina, the umbones small and retuse, and the car- dinal teeth close to the ante- rior end ; as in U. recta Lam. 4. Theliderma: the form is various, but the posterior hinge margin is generally elevated and angulated, and the outside of the valves tuberculated or granulated, — a character not distinct species sent from that country, evidently labelled by the same hand, yet bearing the same specific name. Mr. Lea's Synopsis leaves this part of the subject almost as obsure as ever, because he merely cites the name, without giving any reference to the works of the authors he quotes. By his plan, as novel as it is detrimental to science and all critical inquiry, the author (no doubt, unintentionally) imposes an effectual bar to the ve- rification of his own nomenclature, no one here being acquainted with all the detached papers on these shells printed in America. 268 SHELLS AND SHELL-FISH. PART I. found in any other of these groups* (T. metanevra Raf. fig, 50.). 5. Potomida : the shell rather short and oval ; the umbones prominent, but not so large as in Unio ; the outer surface smooth ; the cardinal teeth thick, perpendicular, but the outer one diverging. These are mostly European shells, and are represented by U. si- nuata Lam., and our P. corrugata (fig. 51.). Between 51 these sub-genera are in- tervening species, or rather types of form, which blend the whole into a continuous chain of affinity ; thus P. si- nuata is so like some of the typical Unios, that the direction of the outer cardinal tooth and the comparative smallness of the bosses alone distinguish them. Leaving, however, these inter- vening or connectant species, and looking only to the types, we shall see by the following table that they have a resemblance to the primary divisions of the whole family, and to the genera of the Unionince. Analogies of the Sub-genera of UNIO. Sub-genera of Unio. Unio. Analogies. Sub-families of Unionidte. Genera of Unionints. UNIO. Ligumea. Shell very much lengthened. IRIDIN^E. MYSCA. LYMNADIA. T General form oval, oblong;} Potomida. } cardinal teeth obtuse, di- > ALASMODONINJE. MEGADOMUS. C verging, sometimes erect. J The analogy of the last three groups is not so satis- factory as the others, and this excites a suspicion that * Except U. cornutus and Msopus. U. nodosa, Wood's Conch, pi. 22. fig. 1, 2., seems to belong to this group. CHAP. X. SUBGENEBA OF UNIO. 269 our Megadomus fills up the interval between such spe- cies as Lamarck's Peruvianus and JEsopus ; but this would exclude the European Unto sinuata, littoralis, &c., which seem closely united to the typical or Ame- rican group by their short, oval shape, and the thickness of their cardinal teeth. On the other hand, we feel persuaded that our Po- tomidce must be kept distinct from the sub- genus Unio; and this will be apparent to every ^SH^gHIiUI one wno looks to tne ^1] ffl annexed cut of the car- i dinal teeth of Unio My- / tilo'ides (fig. 52.),, and those of Potomida corrugata (fig 51.). (253.) Two of these sub-genera, being more than usually perfect in their types of form, or, in other words, in the diversity of their species, will next be glanced at, for the purpose of showing there is but one principle of variation throughout the entire family. We shall first take the sub-genus Unio as here re- stricted. The types of this are seen in those inequi- lateral shells which have been sent to us from America, as the U. Mytilo'ides Raf. and the undatus of Barnes. Next follow those which are nearly round and equilateral, such as U. Torsus Raf. Our U. truncatus, very much elongated, is the third type of form. The fourth, which represents Theliderma, is perhaps the cornutus of Barnes ; while the fifth, which unites the last to the first type, is an American species, formed like obliqua Lea, but with small scattered tubercles down the middle. * This unites with Msopus, and again brings us back to the undatus. Thus, in the confines of a single sub-genus, are types of JEGLIA, in U. Torsus ; IRIDINA, in U. trun- catus; ANODON, (through THELIDEBMA), in U. nodosa ; * I pretend not to enter upon specific names, for nearly all those which belong to species unfigured appear to me one mass of confusion. 270 SHELLS AND SHELL-FISH. PART I. and probably of ALASMODON, in the species mentioned above. We say probably, because,, as there is no es- pecial evidence to prove the fact, we only infer it from this shell having a structure intermediate between no- dosa and JEsopus ; hence, it occupies the same station in its own circle, as Alasmodon does in that of the whole family. (254.) So astonishingly variable, however, are the shells of this family, that we may even carry our ana- lysis still further ; and by following the series of spe- cies which arrange with Unio Mytiloldes, we shall detect the same analogies as are apparent in the last inves- tigation. Thus, some of the species or varieties of Mytiloides (as gibbosus} are almost equilateral ; others pass into Ellipsis and sulcatus of Lea, thus assuming the long shape of truncata arid IRIDINA ; next follows cornutus, as a prototype of nodosa and Theliderma ; and finally) Msopus brings us again to such shells as U. obliqua, and the inequilateral varieties of Lea's gib- bosus. Beyond this point, it is utterly impossible to push analysis, except it be carried into the principle by which the varieties of each species are regulated; and this, we firmly believe, is in conformity with the very same laws. We have seen, in fact, four varieties of the Mytilo'ides, which assume four out of these primary forms. Some are inequilateral (fig* 53.), some trigonal, others are oval, and another oblong : whether there is any one with small nodules to represent cornutus and „_, its prototypes, we know ^ ^ not, but we have no doubt that such a variety will be found.* Mytiloides, therefore, we consider as the most typical species of the whole fa- mily, concentrating, in its own variations, pro- * Since writing the above, we have seen a variety of Mytiloides perfectly answering our theoretical description, in the hands of Mr. Stuchbury. UXIONIN^E. — THELODERMA. 271 totypes of all the natural divisions, large or small,, of the UNIONID2B. (255.) The other sub-genus, which contains sec- tional types, is THELIDERMA ; and this we shall now briefly notice. It will be remembered that we have placed this sub-genus immediately after Ligumia, the type of which is the Unio recta of Lamarck. Nearly all these shells have their posterior margin dilated and angulated, and thus represent the genus Ano- don of Lam. Although the species are remarkably va- ried, they are all known by the external surface being covered by numerous tubercles of different shapes, which stud every part of the shell. Where we find a cha- racter, however trivial it may appear, pervading a whole group, we may be perfectly assured that it is a natural character, although it may not be the only one. (256.) Now, let the conchologist place before him the following shells (fig. 54.); — 1. Irrorata (a); 2. Metanevra (&) ; 3. Cylindrica (c) ; 4. Pustulata* Sw. (d}; and, 5. Plicata (e); — and he will then have what we consider the sectional types of THELIDERMA. It is obvious that the two first have the greatest resem- blance to each other ; both are nearly circular, and tu- berculated ; but irrorata is not winged, like metanevra. Now, this difference, trivial as it seems, is accompanied « We merely use this name provisionally, until we know that by which it has been distinguished in America. 272 SHELLS AND SHELL-PISH. PART I. by a peculiarity in the construction of the animals, first ascertained, we believe, by Mr. Lea. Here, then, we have two obvious modifications of semicircular warted shells — the one winged, the other not. This rounded shape, however, begins to be lost in succeeding species, and we are thus conducted to that singular shell the Unio cylindricus of Say (c). Notwithstanding its un- common length, it yet preserves, in every other part of its outward appearance, such a close affinity to metanevra (6), that, without knowing why, a conchologist would at once place them together. On turning to plicata we see another modification : this species is neither semi- circular, like metanevra, nor elongated, like cylindrica; it is broadly oval ; and, instead of being tuberculated, has merely two or three deep oblique furrows : it exhibits, in short, but one out of the three typical characters, — namely, the winged elevation of the posterior angle. We believe more than two or three species pass under the name of plicata. In one of these, kindly sent us by our liberal friend Mr. Cooper, of New York, and labelled as " a very old specimen," there is but one lateral tooth on the right valve, instead of two ; so that this species or variety actually puts on the very cha- racter of our Megadomus gigas *, and renders both proto- types of Alasmodon. But has Nature no method in these remarkable variations ? Can it be supposed that the devi- ation of species, or of races of the same species, are regulated by no fixed principles, while all the- rest of creation, inconceivably diversified, has been created on one and the same plan ? Every analogy of reasoning, every ascertained fact, is against the supposition. Whence, then, does the species before us put on the very aspect of another genus ? Simply for this reason, — that plicata, and its immediate allies, represent the genus Alasmodon, and that Nature adopts this mode of in- structing us in her favourite theory of representation. With plicata must be associated our Unio rugosus, * It is this fact which so strongly leads me to suspect that there may be some error in our location of Potomida. CHAP x. UNIONIN.E. — THELIDERMA. 273 where the form of the shell is nearly semicircular, so that we again return to irrorata, from whence we first set out. Four types of the group are now disposed of, but another is obviously wanting ; because, although there are representations of four genera of the Unionida, we have not yet noticed the prototype of Anodon. Now, this type is in the Manchester Museum, and was sent to us, many years ago, by our friend professor Rafinesque, without a name. By the annexed figure (d), the con- chologist will perceive that, in its outward appearance, no one would suspect it was really different from the Alasmodon rugosa of Barnes ; yet, on opening the valves, we find the perfect cardinal and lateral teeth of Theli- derma. The anodons are remarkable for the smallness and the depression of their summits j and this is the only shell of its own group which possesses this cha- racter, while its form is exactly intermediate between cylindrica and plicata. Condensing the results of these remarks, we find the sectional types of this sub-genus will represent alT those of the entire family, — and in the following manner : — Analogies of the Sectional Types of THELIDERMA. ^•rtitmnJ Genera Genera T,£ Analogical Characters. of of Types- Unionidte. Unio. Irrorata. Semicircular, but not winged. UNIO. UNIO. Metanevra. Semicircular, and winged. HYRIA. Pustulata. pval^winged; summit, very j ANODM, LYMNAMA. PUcata. * «"<>iMlA-HO „„». PoTo»,D, Thus we find that every thing apparently anomalous in T. cylindrica is at once explained by its being the link between Ligumia and Theliderma; for if a shell so formed had not been discovered, this link would have been wanting. It has been stated that the crassidens, Peruviana, and rariplicata of Lamarck, the undulatus 274 SHELLS AND SHELL-FISH. PART I. and crassus of Barnes, and the undulata and Dombeyana of Valenciennes, are varieties of Le Sueur's plicatus; but as no proofs, so far as we know of, have been brought forward for this opinion, we must withhold our belief from it, — more especially as the same author esteems the Unio sinuata of Lamarck the same as the Mya marga- ritifera of Linnaeus, and the Alasmodonta arcuata of Barnes. These three shells are now before us ; and we consider them not only of different species, but actually of different genera : the first is a Unio, and one of the types of Potomida; the two latter are distinct species of Alasmodon. Furthermore, Lamarck has not given the name of sinuata to the margaritifera of Linnaeus ; for he expressly calls the latter shell, which, we believe, is peculiar to England, Unio elongata. We are not fond of adverting to errors ; but where they have been com- mitted by writers who, on many points, deserve honour- able mention, it is absolutely necessary to show the fallacy of the principles of arrangement from which they have originated. (257- ) On the remaining sub-genera of UNIO — namely, Cunicula, Ligumia, and Megadomus, our remarks must be very brief. The first is at once distinguished by the compression of the summits or bosses, and by being always more or less angulated on the posterior slope : planulata, cuneata, and rubiginosa are typical examples, having the lower lateral tooth remarkably thick, — the singular foliacia of Say obviously representing the Unio cornutus ; Lamarck's purpurata seems to lead imme- diately to the sub-genus LIGUMIA, where the general form of the shell is nearly as much elongated as any of the IRIDIN.E. We consider Lamarck's recta (fig. 55.) as the type, although we think this is also the place for the gibbosa and other elongated species, whose outer car- dinal tooth is not erect, and both teeth more in unison with those of Cunicula and Unio. In all these the shape and direction of the 'cardinal teeth are quite different from * Lea on the Genus Unio, Am. Trans vol. iii. N. S. 1829. CHAP. X. UNIONIZE ^EGLIA. 275 MYSCA, which they nevertheless represent by their pod- like form. The remarkable T. cylindrica, already noticed, unites to this form the tubercles of the sub-genus THE- LIDERMA, which has just been analysed. (258.) There seems strong evidence for believing that our Unio gigas follows THELIDERMA ; in which case it may be regarded as the type of a distinct sub-genus,, which, for the present, we shall name MEGADOMUS. It differs from the T. Peruviana and its allies, by having only one lateral tooth in each valve ; and the bosses are remarkably small and compressed. We have already alluded to the disappearance of one of the cardinal teeth in an aberrant species of Theliderma; and we can now notice a second gradation in an enormous large and very old shell, intimately resembling plicata, but having the second lateral tooth in one valve reduced to a mere vestige. The question is, whether this deficiency is accidental or permanent : all such deviations from the typical characters of the UNIONIN^:, particularly in their teeth, we regard as prototypes of the ALASMODONTIN^B ; but their natural location is very difficult, particularly until the question regarding POTOMIDEA being a genus, or a sub-genus, is decided. (259.) -&GLIA, the second genus, is the represent- ative of Hyria : this is apparent in the general form of their shells, and in the structure of the cardinal teeth. The posterior half is very thick and truncated, so as to form a carinated angle; the bosses approach towards the centre, and are very prominent; the form is thus almost equilateral, and consequently the lateral teeth are T 2 SHELLS AND SHELL-FISH. PART I. unusually short; the cardinal teeth are also very peculiar, as already explained (fig. 47. &) ; the groove between them diverges from the beak in precisely an opposite direction to that which separates the lateral teeth,, — in other words, it is obliquely parallel to the mar- gin of the shell, instead of receding from it. In the comparative size of these teeth there is also a de- cided difference : in Mglia, the inner cardinal tooth is the smallest, while in Unto it is the largest. The typical examples are JE. ovata (fig- 49.), cuneata Sw., and occidens Lea. Unfortunately, however, the genus is not so rich in forms as the last, and hence the links between the sub- generic types are not so beautifully graduated ; but the three species above named are certainly typical, and by means of ventricosa, ater, and siliquoides, lead us to the confines of the group, where we find such species as M. Say's cariosus and ochra- ceus, among which, and some kindred species, there is at present much confusion : these, however, conduct us to the U.radiatus of the American conchologists. This is a very remarkable shell, because it seems the point of junction between Mglia and the next sub-genus (Mys- ca) ; the form of the teeth are consequently very variable: hence we find that, in some varieties of this species, the teeth are like those of ochraceus; in others, the cardinal teeth are nearly equal, as in MYSCA ; and in a very old specimen now before me, the inner tooth is actually the largest. These are all natural variations, and are account- ed for upon the principle that esculent groups or forms vary according to the characters of those other forms which they connect. Lastly, we have a beautiful pro- totype of Theliderma in Canthyria, the type of which is the U. spinosus of Lea. This, and Naidea, are the only sub-genera we shall venture to characterise ; the other two requiring much more study than we have yet been able to give them. (260.) The sub-genus MYSCA follows next, and ob- viously blends into the last. Mysca is the representation of Iridina ; and we consequently find that nearly all the CHAP. X. UNIONIN^E. MYSCA. 277 species are unusually long and narrow, while their in- terior lustre is by far more brilliant and iridescent than in either of the preceding groups. The cardinal teeth, although in some respects like those of JEglia, neverthe- less deserve much attention, because they not only differ from those of Unio and JEglia, but bear a remote analogy to IRIDINA. They are the most crenated of all those in the UNIONIN^ precisely as those of Iridina are the most crenated in the entire family : they are likewise the most parallel to the anterior margin; and although in general distinctly divided, they yet have a propensity, even in individuals of the same species, to unite, and run, as it were, into each other ; so that in some specimens of our My sea ovata (Jig- 66.), these two teeth will be perfectly divided; while in others of a younger age, from the same pond, the division will be only marked by an indentation on the ridge, — the groove itself being almost obsolete. Now, this is precisely in unison with shells intended to represent Iridina, where the lateral and cardinal teeth are united into a crenated line. This vari- ation in shells of the same species is not only perplexing to young conchologists, but to more experienced ones : in general, however, we may consider it as a rule that no Unio belongs to this group, which has the cardinal teeth thick and obtuse ; nor does it comprise any in which one of the cardinal teeth is not immediately beneath the bosses. These positive and negative characters render the discrimination of Mysca comparatively easy. Very T 3 278 SHELLS AND SHELL-FISH. PART I. fortunately, the group, although not so extensive as the first, is yet rich in subordinate types ; we shall, there- fore make some approximation to the natural series of the species, by looking to the following table, wherein each subordinate type is indicated by its most prominent example. Analogies of the Sub-generic Types of MYSCA. Types. Analogies. MyscaovaUi marginal —«•• Nilotica I Oval ; hinge sub-c»nnate ; poste- } A i rior angle winged. j ANO1 frao-ni* ' $" Hinge sub-connate;;cardinal teeth? . iragilis. £ imperfect. j ALASMC (261 .) Among the longest species of Mysca generally known are our two British species, ovata and pictorum, which may consequently be considered typical; and these also have the most crenated cardinal teeth. Following these we have a type from India, represented by tbe mar- ginalis of Lamarck, where the outer cardinal tooth is long and slender, as in Hyria; and the other similarly formed, but much shorter : these shells are also remarkable for having two distinct cardinal teeth, almost alike, in the other or left hand valve, — a structure which is quite different from that of ovata, and indeed of all other Unionidce. Let the malacologist examine the Hyria avicularia and the Unio marginata of Lamarck ; and so far as regards the cardinal teeth, he will find they are formed precisely on the same model : nothing, there- fore, can be more perfect.* Marginalis agrees also with Iridina, in being, without exception, the most iridescent * We even question whether this may not be a relation of affinity, and thus Lamarck's marginata may be the anodontine type in Hyria. MYSCA. 279 of the group : with marginalis must be joined three or four other species, all of which are from China and India. One of these now before us, bears such a close resemblance to the Unio nasutus of Say, that, if the teeth are not examined, it would be impossible to define their difference. Nasutus, however, represents another type, which at present is almost exclusively confined to North America. Here the cardinal teeth greatly resemble those of Say's cariosa and radiata (which come into the circle of .^EGLIA) ; for the outer one is somewhat conic and erect, while there is only a single defined tooth in the left valve. From nasiita we pass, by several intervening species, into the next type, represented by our M. Nilotica, shaped like a small Anodon, but with the teeth of Mysca. We possess three other species, all from the river Nile, and believe there are many others. Finally, we have from America the Unio fragilis, figured very accurately in our Zool. Ittust. 1st Series, pi. 171., but which the Ameri- can conchologists do not appear to understand : it truly belongs to their genus Unio, because the two lateral teeth are well defined, although the cardinal are but slightly developed. Our figure, nevertheless, was drawn from a very old specimen, which did not exhibit the elevated and angulated posterior margin. Now, of all the Unionida so constructed, this makes the nearest approach to the well-known Unio alata of Lamarck ; while, in the imper- fection of its teeth, it clearly represents Alasmodon. We are thus brought round to the group with which we commenced ; and were it necessary to point out the precise point where the circle is closed, we could expa- tiate upon the structure of our M.Mexicana, — an unde- scribed species, and standing intermediate between the first type and the last. It must not be supposed that the modifications of form represented by the five species named in the last table, are merely confined to one or two examples ; even our own collection of specimens and of drawings can produce several. Ovata, for instance, represents a little group of eight species ; marginalis, another of four; nasuta, seven; Nilotica, four; and T 4 280 SHELLS AND SHELL-FISH. PART I. fragilis, two. Now, when we reflect how many more may be in cabinets, and the probability of still greater num- bers being undiscovered, we should be fully waranted in designating these sections as sub-genera ; but so long as any doubts remain regarding the true affinities of our sub-genus Potomida, this plan may be suspended. (262.) The Lymnadia alata is one of the most re- markable shells of this sub-family; not so much on ac- count of its beauty, but as holding a more isolated station than any yet noticed. That it has a strong resemblance to Anodon, is indisputable ; but that it has a much stronger one to the Unionince, cannot be questioned. — Now, every one who draws the distinction between analogy and affinity, immediately perceives that the first of these resemblances is purely analogical; while the other, as Lamarck, Say, and Barnes have correctly judged, is one of absolute affinity : it is needless, there- fore, to discuss this matter further. At present, Lym- nadia alata (fig. 48.) stands almost alone as the repre- sentative of that sub-genus which typifies the anodons. In conformity with this analogy, we find the posterior dorsal margin remarkably elevated, dilated, and winged. The ligament also is connate, — that is, entirely covered by a prolongation of the testaceous substance of the valves: the bosses small, and the shell itself oval and depressed. The cardinal teeth are very peculiar : they are compressed and crenated like those of Mysca; but the inner one is generally the largest; and the direction of the groove which separates them, is either perpendicular, or diverges from the anterior margin of the shell. It is clear that our Unio fragilis* either enters in this group or is at the confines of the last: the next question is, what others can be arranged in the same genus with Lymnadia ? We entertain little doubt that the Symphynota compressa of Mr. Lea is one of these, f In this curious type, the cardinal and the lateral teeth are perfect, and it has the complete external aspect of * ZooL 111. 1st Series, pi. 171. f We only know this from the very excellent description and figure in Mr. Lea's paper. CHAP. X. UNIONINJE. LYMXADIA. 281 Anodon : it is also so perfectly connate, that Mr. Lea, look- ing only to that circumstance, actually places it close to L. alata. It is nevertheless a distinct type, and seems to represent Anodon in this sub-genus : the cardinal teeth, in short, strengthen us in the belief that Potomida suc- ceeds to Lymnadia. We shall therefore introduce it here, leaving its natural affinities still open to future inquiry. (263.) In regard to the shells provisionally placed in the genus POTOMIDA, we have some doubts. We feel al- most convinced that the types do not belong to the genus Mysca ; and yet some of the aberrant species approach so closely to such shells as M. pictorum and ovata, that the gradation, to ordinary eyes, appears perfect. We have one or two species from Brazil, and others from North America, but most of the types seem to be European These present us with the folio wing distinguishing charac- ters : the form, of course, is variable in the species ; but it is never so long and attenuated as Mysca; the breadth, also, is greater, and the extremities more obtuse. The ty- pical species, P. corrugata ( fig.57 .)j*nesrly as round as the generality of the Venus-shells : the cardinal teeth are always two, — not thin, lengthened, and com- pressed as in Mysca, but thick, short, and strong, so as to resemble the true American unios ; like these latter, also, the inner cardinal tooth is decidedly the largest — but then they are divided like those of MYSCA and J^GLIA. The size of the teeth, with the general shape, and robustness of the shell, in- duce us to think that Potomida is not naturally associated with either Mysca or Unio. The littoralis of Lamarck, common in the rivers of France, will show all these cha- racters ; but in another Continental species, the Unio sinuata Lam., the form is more lengthened ; and by the direction of the cardinal cleft, this shell seems to approxi- mate still more to the typical Unios. Next we have the 282 SHELLS AND SHELL-FISH. PART I. Unio batava of the same country,, where the teeth begin to resemble those of Mysca; but they are still short, strong, thick, and distinctly separated. Proceeding thus in the natural series, without caring to circumscribe our groups by arbitrary characters, 58 we come to P. Sicula (fig. 58.), a new spe- cies, found by us in the lakes of Leontini in Sicily : here we have a still nearer approach to My sea than what is made by Batava : the form of the shell, indeed, is that of Mysca ovata; but the teeth are still thick, and the inner one still preserves the typi- cal character of being thicker than the other. The P. elongata, also from Sicily, would seem to complete the union of this sub-genus with Mysca. Whether we are to look to this as the union of the three aberrant genera of the Unionince into one circle, or to take it as pre- sumptive evidence that these shells form only a division of Mysca, is uncertain. The question is, are they really distinct types ? If we merely look to Mysca pictorum or ovata, and Potomida litoralis or corrugata, the differ- ence is very remarkable ; but on placing between them Potomida Batava, Sicula, and elongata, the extreme differences are softened down, and we become doubtful as to the limits of the group.* There are several North American shells which we suspect will clear up this point, and hereafter enable us to discover the true typical cha- racters. (264.) The HYBIN^J constitute a small but very distinct sub-family, remarkable both for its characters * Our collection of Unionidee, upon which these remarks were founded, has unfortunately passed into the hands of others, and prevents us from again investigating this question. We shall feel particularly indebted to those conchologists of America who study the Unionida, for specimens, ac- curately named, from their " Western Waters," of all the species they can part with, promising to return others in exchange, from New Zealand. Letters and parcels should be directed to us, to the care of John Willis, Esq., Liverpool. CHAP. X. HYRIN^E. 283 and its geographic distribution. All the species yet known, are from the rivers of Tropical America and Australia, — not one having been found north of the line. Indeed, it may be almost said that the range of the genus Unio is bounded by the same latitudes ; for of all the UNIONIN^I we have yet seen, not more than two have been brought from South America, and these do not belong to the most typical groups. The HY- RIN.E are distinguished by the angulated or wedge- shaped form of the shell, and the winglike projection of its hinge or dorsal extremities. The second cha- racter is in the narrow linear form of the cardinal teeth, which are on one side of the bosses, not beneath them: these teeth also diverge to the anterior edge, and are always more or less linear. The third cha- racter is so very simple and constant, that it may be recognised by the merest tyro ; the bosses or summits of the valves are wrinkled or grooved transversely ; that is, in a line from the apex to the basal margin. This singular peculiarity, which pervades nearly all the types we have yet seen of the HYRIN.E, is directly opposed to the characters of the UNIONINJE, where, if the summits are wrinkled, the wrinkles are placed longitudinally, or in a direction from the anterior to the posterior ex- tremities. In what way this may be connected with the natural habits of the animals, is totally unknown. (265.) The passage from the UNIONIN^: to the HY- RIN.S: is through My sea in the former, and Iridea in the latter. The gradation from one to the other is beautifully perfect. Iridea has the strongest possible affinity to Mysca, in the general shape of the shell, and in the structure of the cardinal teeth : the form, how- ever, is more oval than elongated; the ends more obtuse j the posterior end of the hinge margin more elevated, and the summits smaller. These, however, are points of inferior moment. The chief distinction is in the length and narrowness of the outer cardinal tooth, and the almost total absence of the other : hence it is, that in such shells there are always two distinct 284 SHELLS AND SHELL-FISH. PART I. cardinal teeth in the left valve ; whereas, in the UNIO- NIN^E, this valve has scarcely ever more than one. When, however, both are present in the right valve, the inner one is always under, and not on the same line or on the side of the outer tooth. The most aberrant species of My sea have something of this ap- pearance, not very apparent to young conchologists. But there is another and a more easy discrimination. Of thirteen species of Iridea now before us, each and all have the bosses or umbones wrinkled transversely, as in Hyria. We cannot, indeed, expect that every species will be so marked, for then there would be an absolute line of demarcation between Iridea and Mysca, which is contrary to nature ; but the facts now stated will enable any one to discriminate the two types. The next sub-genus is Lamarck's CASTALIA, of which but one species is generally known. Reasoning from ana- logy, it follows Iridea ; but if so, the minor types of connection are wanting. It is a cockle-shaped shell, nearly equilateral, and 59 bears a strong resem- blance to Mglia cune- ata. From this rare and somewhat isolated type the transition to Hyria (fig. 59.) is ren- dered easy and natural by means of Hyria cor- rugata Lam. ; and Hy- ria elongata indicates a passage to that elongated form which has not yet been discovered, and which must represent either Alasmodon or Iridina* Such a shell we remember to have once seen at King's Auction - rooms, but by some accident neglected to take notes, or to secure the specimen. In the sub-genus Na'ia, which we arrange under CASTALIA, we have a form connecting the C. cordata * with Iridea. We have before us six * I use the prior specific name of Humphrey rather than Lamarck's anibigua, which throws an unnecessary doubt on its being a species. CHAP. X. HYRIN^! AND UNIONIN^E. 285 species, four of which are from India, and two from Australia. They are short, roundly oval shells, with the umbones well defined, and placed towards the middle : from this .results their peculiar character. The lateral teeth are short, and not a great deal longer than the cardinal teeth ; these latter being strong and thick, without being short : they are much crenated, yet without any ridge ; so that they have the appearance of being broken off. Their immediate affinity to Iridea is proved by the Na'ia elongata, from New Holland, having the form of one type, and the teeth of the other. This interesting species, once the property of admiral Bligh, was purchased by us at his sale. The pecu- liarities of Lamarck's Unio Australis (Hyridella Sw.), and its affinity to Iridea, lead us to arrange it as the anodontine type of the HYRIAN.E, although it may pos- sibly be an aberrant example of Iridea : the bosses, how- ever, are not striated, and the whole shell has very much the aspect of an Anodon. Of the fifth type, connecting this sub-family to the next, we know nothing more than what has been already stated. As the remaining genera of the Unionida are neither rich in the number of their forms, nor abundant in their species, we shall mention them with more conciseness. (266.) According to the views here taken of the HYRINJE, we may thus compare the four genera, just defined, with the circle of the Analogies of the HYRIN.E and the Genera of the /*„„//,„,•<,* Genera of the Hyrin*. Analogies. Unionirue. r»«TAii ("Shell trigonal; posterior side 7 ;svn* i truncate and short. j JEGLIA. HYRIA. Posterior side lengthened. UNIO. ? POTOMIDA. C Compressed, broad; bosses not") TT.-MWAT..A ^ striated, retuse ; teeth slender J ******** C Lengthened oblong; bosses small; } IRIDEA. -4 inner cardinal teeth very small, > MYSCA. C almost obsolete. 3 286 SHELLS AND SHELL-FISH. PART I. The type which we consider unknown, is that which leads immediately to IRIDINA, and would consequently be deficient in some of the teeth. The other four are such obvious representations of their prototypes among the UNIONIN.E, that we need not detain the reader by any additional remarks. (267.) Of thelRiDiN-as, only three typical species have been yet discovered ; and these, we believe, are all from the river Nile. (7. elongata, fig. 60.) The form of the whole group has been before stated ; the shell is almost of equal breadth throughout, with the posterior end nearly, if not quite, as broad as the anterior. This great elongation of the shell must extend, of course, to the animal ; and for this reason we admit into the genus Iridina a singular shell from the same river (Iridina Nilotica Fer.), but which has the hinge line only " slightly crenulated at the umbones." * Here it is that Nature, as it were, is hovering between the confines of this type and the Anodontiruz, and plainly intimates to us which will be her succeeding group. (268.) The ANODON TIN JE form a more numerous sub-family than the two last. Tropical America ap- pears richer in these shells, than any other part of the world. Although one of the sub-genera is peculiar to Asia, the typical form (represented by our common Anodon anatinus) occurs both in Europe, Asia, and North America, but under different modifications, which will render it necessary to distinguish them as sub-ge- nera. We arrange the whole under the five principal genera of Lamproscapha Sw., Symphynota Lea, Anodon Lam., Hemiodon Sw., and Patularia Sw. The first of these contains such shells as the A. ensiformis, siliquo- sum, &c."j", which have the shape of Iridina,, but are * Zool. Journ. i. 55. The name of Pleodon cannot be substituted for that of Iridina, as applied to the typical species. t From Brazil, figured in Spix and Martius's Tettacca Fluviatilia. &c., published in 1827. CHAP. X. IBIDIN^E. - ANOBONTIN.E. 287 destitute of any crenations, or plate, below the hinge mar- gin. These obviously lead to Symphynota, where the form is oval and winged ; while a slender lamellar tooth ex- tends the whole length of the shell. Following this we have the typical genus Anodon, where the plate in ques- tion is entirely wanting. There are many striking mo- difications, however, in the form of these shells, which may hereafter point out the sub-genera : — in Anodon proper, the form is transversely oval or oblong, and the bosses very small and compressed: Patularia has the um- bones remarkably swollen, or ventricose ; and the shell almost round : lastly, the genus Hemiodon includes those which have a slight tubercle, or indication of the car- dinal teeth; thus leading to the ALASMODONTIN^E. (269.) Assembling these types in a tabular form, we shall find they possess the usual analogies. Analogies of the Genera of the ANODONTIN^;. Genera of the ,. .. Sub-families of Anodontince. Analogies. Unionid*. ANODON. Pre-eminently typical. UNIONIN^E. SYMPHYNOTA. Hinge margin or teeth lamellar. HYRIAN.E. LAMPROSCAPHA. te-th' and *«* lonS ' no] PATULARIA. ~ Shell nearly round ; no teeth. ANODONINJB. HEMIODON. { ™*g£«* sinuated or tubercu' } ALASMODONIN*. Not having carried our analysis into the sub-genera, we shall not venture to name those which have the aspect of being such. It is plain, however, that there are aberrant species, if not sub-genera, in Symphynota and Anodon. These two are probably connected by Anodon rubra, which has a distinct elevated ridge, analogous to the lamellar tooth of Symphynota. The bosses, again, of our common Anodon are small and compressed ; while those of A. trapezialis Lam., and other large species, are remarkably ventricose. The Anodon purpurascens*, * Zool. III. pi. i. 260. 288 SHELLS AND SHELL-FISH. PART I. again, has the rudiments of a very thin and short lateral plate. It may be proper to observe in this place, that Dipsas was the original name imposed by Dr. Leach to this sub-genus ; but Larentini, so far back as 1768, had given this name to a genus of reptiles : and as this is an insuperable bar to its repetition, we gladly adopt that of Symphynota Lea, under the restrictions here men- tioned. (270.) The last sub-family is that of the ALASMO- DONTIN.S:, the typical species of which are all from the rivers of America. They are connected to the anodons, in the most graduated and perfect manner, by our genus Hemidon; and the first type is probably represented by the Unio calceola of Lea : then follows the typical form, as seen in Say's original Alasmodon undulata (fig.6l.); our genus Uniopsis appears to suc- ceed this , then we have the elongated form in Schumacher's Margari- tana; and, finally, the anodoniform, or most aberrant type, is seen in our Complanaria gigas and rugosa.* The whole of these constitute one of the most natural divisions in the family. Typically considered, they are without any distinct lateral teeth ; the hinge-plate being either long and merely con- vex, as in Margaritana ; or short, flattened, and obliquely grooved, as in Complanaria. The cardinal teeth are always present, but vary in each type ; hence they fur- nish an admirable clue to the analogies of the genera. Nothing appears known of the animal; but this is not material to our present purpose, since the variation of the shell is quite sufficient to guide us in their natural * Mr. Lea, in his artificial arrangement, places these two shells in widely different divisions, because one, he says, is " symphynote," and] the other " now-symphynote : " they are the Alasmodonta complanata and" rugosa of American writers, and are most naturally connected. CHAP. X. ALASMODONTIN.E. 289 arrangement. The ex- C2 ^**=™*-^ ceedingly oblique teeth of our Uniopsis radiata* (fig. 62.) show it is the prototype of Unio, and might have been there placed,, but for the want of lateral teeth. The triangular and cuneated shape of Alasmodon un- dulata reminds us of JEglia. The single cardinal tooth of Calceola truncata t accords with the tubercles of Hemiodon; while the compressed bosses and dilated posterior side of Compla- naria preserves the analogy between this sub-genus and its prototypes Lymnadia, Theliderma, and Anodon. Finally, we come to Margaritana, which; every one must perceive, puts on the aspect of Mysca, Ligumia, Potomida, and the Iridince. Whether the whole of the shells retained by us in this last genus really enter into the circle we are at present tracing, or that such as have an obsolete lateral tooth should naturally be arranged with the Potomida littoralis, &c., cannot, of course, be yet determined ; nor do we feel certain that Calceola is the connecting type with the Anodontina. And yet, as all these find their representatives in the lead- ing divisions of the UNIONID^, they become absolutely types of genera, equivalent in rank, although not in numbers, to the genera of the sub-family UNIONIN.S:. This will be further apparent from the following expo- sition : — * I suppose, from the name, that this is the Margaritana radiata of Lea's Synopsis, but, as no reference is made to where the shell is described, or any information beyond its being " non-symphynote and smooth," I affix this name at a venture, merely for my present purpose ; the real name, if described, can always be made "out from the figure here given. Since writing the above, my kind friend Mrs. Corrie (who has a noble series of Unionidce in her fine collection) has sent me a specimen of this type under the name of Alasmodon inflata ; the teeth are not near so oblique as in that here figured. t Under the common name of Unio calciolus, we have received three distinct species from America. U 290 SHELLS AND SHELL-FISH. PART I. Analogies of the Genera of the ALASMODONTINJE. jtnn1na-fn1 Sub-families Genera Sub-genera Genera. Analogical fth f f Characters. Unionida.. Unionin*. Unto. f Inequilateral ;^ the cardinal Uniopsis. <, l^g from the f UNIONIN^- UNI°- Un*°- 1 anterior I L margin. J TCuneate, andT Alasmodon. < nearly equi- J-HYRIN.E. ^EGLIA. Cunicula. C lateral. 3 Calceola. ? ALASMODONINJS. POTOMIDA. Megadomus. r Winged ; the"! Complanaria. -| ^d^ much f AN°DONTINJE. LYMNADIA. Theliderma (, compressed. J r Oblong oval, 7 Margaritana. < greatly J-IRIDINJB. MYSCA. Ligumia. C lengthened. 3 (27 1.) Having brought our rapid exposition of this family to a close, we may now offer a few general re- marks upon the whole. The Unionidte, of all the groups of the DITHYRA, is that which contains the greatest modifications of form ; insomuch that it becomes almost impossible, in some of its minor divisions, to determine which are species, and which varieties. Hence has originated the idea, entertained by several conchologists, that they constitute but a single genus ; while others have gone so far as to suspect that there is in reality but one species of Unio, and f( perhaps of the whole family : " such, at least, were the sentiments entertained some years ago, although we believe they no longer exist. Upon this principle, the equally ex- tensive and varied family of HelicidfB should form but one genus, or rather but one species, which might be called Helix or Limax terrestris, because, it lived upon land.* It is useless to prove, that by this false and vicious sort of generalisation, we should return back to * The naked slugs and the land snails pass into each other by such gra- duated shades, that no " well-marked and absolute characters" can be .found to separate them. CHAP. X. ALASMODONTIN^:. 291 the dark ages of zoology, and produce the same sort of confusion and ignorance which then reigned. But, then., it may he asked, how can genera be retained in our systems, which actually blend into each other, and whose distinctions thus become lost ? This objection has been repeatedly answered. Genera which are really natural, are always thus united, because they show us all the connecting links of nature. But genera which contain only well-defined and isolated characters, so that no ordinary person can confound them, are not perfect, because their connecting links to others are wanting : they are fragments of the chain, having its gradations disturbed, dissevered, broken ; — hence such groups are fragments only of what has been, or may be, a natural assemblage. Our divisions of sub-families, genera, sub-genera, and sections, are mere conventional terms employed to denote groups of different sizes, pos- sessing, in the majority, certain primary characters which are termed typical. It matters not upon what cha- racters these divisions are founded in the Unionidce and the Helicida, provided none can be drawn from the animal ; but it is most essential that disruptions of kindred species should not be made, — for then the harmony of nature is destroyed. Now, this leads us again to advert to the different sorts of resemblances natural objects bear to each other. The confounding of analogy and affinity, which has led to the greatest confusion in every branch of zoology, has been particu- larly conspicuous in this : every conchologist, for in- stance, perceives that Ligumia recta, Mysca ovata and nasuta, Iridina ekmgata, and Alasmodon margaritifera, have a very strong resemblance to each other. Now, if this resemblance were one of affinity, it naturally would follow that all these shells belonged to the same natural group : they possess one character in common, — that of being particularly long, pod-like shells ; yet if any me- thodist, looking to this only, and disregarding all other characters, make them into a genus, he would commit a palpable outrage on natural classification. So, in like u 2 292 SHELLS AND SHELL-FISH. PART I. manner, if he took all the winged or connate shells, and, holding as trivial their other characters, proceeded to place them in a separate genus, he would be doing the same thing, — he would he confounding objects which merely represented each other analogically, or, as it were, allegorically, under the belief that they were bond fide connected by affinity, and followed each other in the scale of nature. (272.) But if all this be admitted, the difficulty of separating species from varieties still remains : a species, it has been said, is the only absolute division in nature ; and did we look to the vertebrated, and even the annu- lose, animals, we might be tempted to adopt this as an axiom ; but in regard to the present family, at least, it cannot be maintained, for it receives a direct contradic- tion. The mode of generation in the whole of the Dithyra precludes the theory of promiscuous intercourse, and the consequent production of hybrids.* The vari- ations, therefore, are spontaneous, and lie beyond our in- vestigation. We have seen, however, in the case of the Unio Mytil'iodes, that while Nature appears to disregard all her usual bounds, and to indulge in almost endless diversity, she nevertheless strictly confines herself to the same plan she has pursued in all other groups. Her vari- ations are upon the same system as that which pervades the animal world. She creates, in short, a type, all the variations of which have a reference to, and often the very aspect of, those particular forms which mark the primary divisions of the whole family. This theory, borne out in almost every group here laid before the reader, will materially, if not absolutely, guide us in determining the limits of species, and consequently of varieties. We trust the rising school of American ma- lacologists will confirm this by a renewed investigation of the inexhaustible profusion of Unionida with which their noble rivers abound. Having seen but very few of * On all anatomical facts, we look to the illustrious Cuvier as a para- mount authority ; he expressly says all the Dithyra are hermaphrodites. Mr. Lea, however, mentions male and female shell-fish of the same spe- cies. Is there no error in this ? CHAP. X. BRANCHIOPODA OHELYOSOMA. %Q3 the valuable Essays, &c. published in their own country on the species, we have not ventured to carry our analysis so far : our object for the last twenty-three years has been to discover the fundamental principles of their natural arrangement. How far we have done this, time alone will show. Much uncertainty, indeed, hangs over the location of one or two genera ; but this, however desirable to be cleared up, affects not the principle itself, — for that coincides with all we know of the universal laws of animal variation. (273.) Our remaining space is now so contracted, that we can do no more than merely glance at the two remaining tribes of the DITHYRA. The Branchiopoda, indeed, have already been slightly noticed (238); while the annexed cut (fig. 63.) of Mr. Broderip's CHELYOSOMA will give a good idea of this most extraordinary animal. According to that very able naturalist, it adheres to stones by coriacious processes from the lower part. It must be observed, however, that on this lower or cup- shaped part, there are slight traces of separation into plates, but without internal muscular fibre. The upper surface is flat, and consists of eight coriaceous, some- what horny angular plates, which are so disposed that the branchial orifice (a) is surrounded by three plates, and the anal orifice (6) by four : each of the plates are marked by elevated striae, as in the tortoises. The valves of the orifices are opened and closed by muscles, adhering at one end to the inner surface of the tunic (not of the mantle), and on the other to a small papillary process on u 3 294 SHELLS AND SHELL-FISH. PART i. the valves themselves. Besides this set of muscles, and within them, is another set, which passes laterally from one papilla to another. Other muscles enable the ani- mal to contract or dilate itself. The ovaries, viscera, &c., were in too decayed a state for examination ; but the mantle appears to adhere only to the orifices, each of which has six valves.* Wherever this animal is'placed, its extraordinary analogy to the Cyclobranchia and the other cheloniform types, will still be the same; and our present impression is, that it represents the chitons in this division of the order rather than in that of the Tu- nicata. (274.) Having now completed our exposition of the two great typical divisions of the TESTACEA, in which are included the whole of the univalve and bivalve shell- fish f, we must reluctantly close this part of our volume. The whole of the aberrant orders, as the Cephalopoda, the Parenchymata, and the Nudibranchia, together with the radiated and the coralline Mollusks, will therefore re- main open to future investigators of the natural system, and they may possibly form hereafter the subject of another volume supplementary to this. * Abridged from ZooL Journal, vol. v. p. 46. f Excepting thoge of the Cephalopoda or Nautilus order. PART II. A NATURAL ARRANGEMENT OF THE UNIVALVE AND BIVALVE SHELL-FISH, COMPOSING THE ORDERS GASTEROPODA AND DITHYRA OP THE CLASS TESTACEA. Chief Abbreviations. Bligh Cat. Catalogue of the Bligh Mart, or Mar. Martini. Shells. Sow. Gen. or S. Gen. Sowerby's Chem. or Ch. Chemnitz. Genera of Shells. Ency. Meth. or En. M. Encyclo- Sow. Man. Sowerby's Manual of pedie Methodique. Conchology. Lam. System of Invertebrated ani- Tank. C. Tankerville Catalogue. mals ; the No. refers to his series Zool. 111. i. & ii. Zoological fllus- of species in the original edition. trations, First and Second Series. ORDER GASTEROPODA. TRIBE ZOOPHAGA. Carnivorous Gastropods. FAMILY 1. MURICID^E. Murexes and Whelks. Pillar never plaited ; shell spiral, the base narrowed, and either truncate or slightly produced. SUB-FAM. 1. MURICINJE. Murexes. Spire as long as the aperture ; exterior rough ; the whorls marked with varices ; aperture wide. MUREX Lin. Varices from three to five on each whorl ; u 4 296 SHELLS AND SHELL-FISH. PART II. inner lip smooth ; the spire much shorter than the aperture ; an internal groove at the upper angle of the aperture. Murex Lin. Canal very long ; shell armed with acute, cylindrical, tooth-like spines, mostly arranged in three varices. tenuispina. Sow. Gen. f. 2. cornutus. Mart. 1 14. f. 1057. crassispina. Mart. f. 1052-4. brandaris. Ib. f. 1050. 1058. Haustellaria Sw. Canal excessively long ; shell with- out spines ; the varices tuberculated. erythrostoma Sw. Sow. Gen. f. 1. (Murex haustellum L.) Phyllonotus Sw. Canal moderate ; varices foliated, la- ciniated, compressed, or resembling leaves (fig. 66. d). inflatus. Mart. 102. f. 980. endeva. Ib. 107. f. 107,108. eurystomus. Zool.Ill. ii. 100. (Aberrant.) imperialis. Ib. pi. 109. adustus. Ib. f. 990, 991. cervicornis. Sow. Gen. f.4. trunculus. Ib. f. 1018, 1019. Scorpio. Ib. f. 3. saxatilis. Ib. f. 1011, 1012. calcitrapa. Mart. 102. f. 982. palmarosee. Lister. 946. f. 41. brevifrons. Ib. f. 983. capucinus. Chem. 192. 1849. axicornis. Mart. 105. f. 989. Murlcanthus Sw.* Varices numerous, foliated ; spire short; margin of the outer lip with a prominent tooth near the base. radix Sw. Zool. 111. 2d series, melanomathus. En. Meth. pi. 113. 418. f. 2. Pteronotus Sw. Varices three, compressed, fin-shaped ; canal moderate, generally closed by the union of the two lips at their base. pinnatus. Zool. 111. ii. pi. 112. tricarinatus. En. M. 418. f. 5. tripteroides. En. M. 41 7. f. 3. phyllopterus. Sow. Gen. f. 5. trigonularis. Mart. f. 1031. gibbosus. En. M. 418. f. 1. hemitripterus. En. M. 418. acanthopterus. Ib. 417. f. 2. f. 4. uncinarius. Mart. f. 1034-5. MURICIDEA Sw. Spire more produced, as long or * This type was originally called Centronotus; but as that name had been previously given to a genus of fishes, we substitute the above. PART II. 3IURICINJE. •CASSIN^E. 297 longer than the body whorl; varices numerous; no in- ternal channel at the top of the aperture, (fig. 65. c.) lamellosa. Chem. f. 1823-4. scaber. En. Meth. 419. f. 6. magellanica. En. M.419. f.4. hexagona. Ib. 418. f. 3. peruviana. Ib. f. 5. erinacea. Mart. f. 1026. senticosa. Ib. f. 3. VITULARIA Sw. General habit of Muricidea, but the inner lip is depressed and flattened as in the Pur- purinae; varices simple, nearly obsolete (fig. 65. e.) tuberculata Sw. En. M. 419. f. 1. (Murex vitulinus Auct.) TRITON * Lam. The varices few, and placed alternately, (fig. 64.) australis. Sow. Gen. f. 1. lotorium. Ib. f. 1. (fig. 66. e) anus. Jb. f. 2. clavator. f. 3. variegatum. (fig. 65. d) RANELLA Lam. Varices forming a ridge on both sides of the shell ; channel short, marginata. Sow. Gen. f. 2. spinosa. En. M. 421. 5- caudisata. Ib. f. 1. crumena. Ib. 421.3. SUB-FAM. 2. CASSIN^E. Shell large, ventricose, generally smooth ; spire very * This is the only character by which this group, as a genus, can be dis- tinguished ; and this is exceptionable, because there are some species, like T.clandeslinum (fig. 64.), which have the outer lip thickened, and are with- 298 SHELLS AND SHELL-PISH. PART II. short ; the base truncate and emarginate, or with a short recurved channel ; inner lip toothed or plaited.* HARPA Lam. Varices numerous and regular, forming longitudinal ribs, coronated near the suture ; aperture and lips highly polished ; base truncate (fig. 65. &, c). multicostata. Sow. Gen. f.l. crenata Sw. Bligh, Cat. CYPR.ECASSIS Stuchbury. Shell oblong, oval, ventri- cose, without varices ; spire very small ; aperture cyprseiform ; outer lip thickened, convex, and ad- vancing on the spire ; inner margin regularly toothed ; inner lip thickened, convex, and spreading on the body-whorl, without being detached ; pillar angu- lated internally, and crossed by uniformly slender plaits ; canal very short, reposing on the body-whorl; aperture very narrow, with a recurved channel above, testiculus. Mart. f. 375. ? crumena. Mart. 37. f. 379. rufa. Ib. 32. f. 341. harpaeformis. Lam. No. 26. f CASSIS Lam. Shell ponderous, marked with varices ; out any varices. There is, in fact, every modification of shape among the Tritons as they now stand ; some have the aperture wide, others narrow ; the channel is either very long or truncate ; the spire greatly lengthened or greatly depressed ; the pillar toothed or smooth ; the varices either alter- nate or none. But, the sub-genera not having been determined, I leave the group in this confused state. These facts, better than any theoretical arguments, show the absolute necessity of defining the sub-genera. , * Except in Dolium and Harpa. f Uniting this genus to Harpa. PART II. CASSIN^E. NASSINJE. 299 outer lip (typically) considerably dilated, with a pro- minent,, callous, and detached rim ; inner lip inflected, broad, flattened, dilated in the middle, and toothed ; aperture narrow, irregular, (fig. 65. a.) cornuta (type). Chem. pi. flammea. En. Meth. 406. f. 3. 184, 185. (fig. 65. a.) (Aberrant.) tuberosa. Mart. 38. f. 382. fasciata. Mart. 37. f. 384. CASSIDEA Sw. Aperture wide ; outer lip never broad or flattened, but sometimes slightly inflected ; inner lip spreading, but never dilated or detached beyond the base into a prominent rim. (fig. 66. a.) glauca. Sow. Gen. f. 1. zelanica. Ib. 18. plicaria. Chem. f. 1459-60. sulcosa. Seba. 68. f. 14, 15. areola. En. M. 407. f. 3. granulosa. Mart. f. 344-5. Zebra. Chem. f. 1457-8. Saburon. Gualt. 39. g. decussata. Mart. f. 360-1. semigranosa. Lam. No. 23. ringens Sw. Bligh, Cat. vibex. Mart. 35. f. 364-6. achatina. En. Meth. 407. f. 1. erinaceus. Ib. 35. fig. 363. pyrum. Lam. No. 17. DOLIUM Lam. Shell ventricose, inflated, smooth ; spire very short ; outer lip thin, not inflected ; base ge- nerally truncate and emarginate. (fig. 66. 6.) D. olearium. Sow. Gen. f. 1. fimbriatum. Ib. f. 2. SUB-FAM. 3. NASSIN^E. Generally small ; tbe spire longer than the aperture * ; the base either truncate, or with a short recurved channel; inner lip often dilated and spreading ; some- times granulated, but never toothed ; a prominent ridge or fold at the base of the pillar; outer lip crenated within. CASSIDAREA Lam. Ventricose ; spire short ; inner lip spreading, and detached at the base ; outer lip thick- ened within ; canal slightly lengthened, and turning upwards ; representing Cassis. echinophora. Ency. M. 405. f. 3. Thyrrena. Ib. 4O5. £ 1. ONISCIDIA Sow. General shape of Cyprcecassis, but Jess ventricose, the base more attenuated, and the canal * But in the aberrant genera it is shorter. 300 SHELLS AND SHELL-FISH. PART II. truncated; spire very short; both lips thickened., the inner granulated, the outer inflected and toothed ; aperture narrow, (fig. 66. c.) oniscus. Chem. 1872-3. cancellata. Sow. Gen. f. 1 — 3. VEXILLA Sw. General shape of Purpura ; the inner lip flat- tened and depressed; the outer, when adult, thickened,, in- flected, and toothed ; aperture wide. picta Sw. Chem. pi. 157. f. 1504-5. (fig. 67.) NASSA Lam. Small ; spire longer than the aperture ; the inner lip, in the typical forms, greatly dilated, thickened, and often with a prominent margin ; outer lip simple, crenated ; aperture wide, with a groove above ; pillar with a basal ridge ; base truncate, (fig. 68.) N. arcularia. Ency. M. 394. f. 1. clathrata. Ib. f. 4. papillosa. Sow. Gen. f. 5. CYCLONASSA* Sw. Shell small, depressed, neritiform, nearly round ; inner lip forming a vitreous, spreading mass ; no internal canal or tubercle on the inner lip ; basal notch nearly obsolete ; outer lip smooth, entire, thickened. C. neritea. Ency. M. 394. f. 9. Sow. Gen. f. 3. SUB-FAM. 4. PURPURIN^E. Oval; spire much shorter than the aperture, which is very wide ; inner lip not defined, but vitreous ; pillar broad and flattened ; outer lip rarely thickened or inflexed, RICINULA Lam. (fig. 71. d.) Outer lip dilated, and often forming digitated processes externally, but the margin broad, much reflected, and toothed internally ; inner lip flat, broad, generally toothed ; spire very small, -j- planospira. En. M. 397.5. digitata. Sow. Gen. f. 3, 4. horrida. Sow. Gen. f. 1. morus. Ib. f. 2. * The fanciful and inapplicable name of Cyclops, given to this type by De Montford, designates a well-known genus of Crustacea. f Except in those species, like R. morus, which lead to Purpura. PART II. PUBPUBIN-SS. BUGGING. SOI CONCHOLEPAS Lam. Patelliform ; spire lateral, nearly obsolete; pillar none. C. Peruviana. Sow. Gen. (fig. 71. a.) MONOCEBOS Lam. Spire moderate; a strong tooth-like process, at the base of the outer lip. (fig. 69.) M. imbricatum. Sow. Gen. f. 1. cingulatum. Ib. fig. 4. MICBOTOMA Sw. Pillar very broad and curving inwards ; aperture effuse ; the notch at the base small, and nearly obsolete ; spire very short. patula. Mart. 69. f. 758, 759. persica. En. Meth. 397. f. 1. unicolor Sw. Chem. f. 1449. PUBPUBA Lam. Spire more prominent ; inner lip flattened ; the basal notch wide and distinct.* (fig. 70, 71. &.) P. coronata. En. Meth. 397. f. 1. succincta. Ib. 398. f. 1. SUB-FAM. 5. Spire always as long as the aperture, and * United to Ricinula by P. columellaris, Ency. Meth. 398. fig. 3., and Ricinuia morut, Ency. Meth. 395. fig. 6. 302 SHELLS AND SHELL-FISH. PART II. typically of great length ; base truncated,, deeply notched ; inner lip smooth, convex. LEIODOMUS Sw. Shell very smooth, nearly polished ; spire acute, slender, lengthened ; of few whorls ; aperture effuse; inner lip thickened and spreading; base of the pillar curving inwards. 8 species. Achatinum. En. M. 400. f.4. Quoyii Sw. Voy. d'Astrol. vittata. En. Meth. 402. f. 4. 31. f. 17. TEBEBRA Lam.* Shell subulate; spire excessively long, and of numerous whorls ; pillar straight ; the base curving outwards (fig. 71. e). maculata. En. M. 402. f. 4. Babylonica. Ib. 402. f. 5. BUCCINUM Linn. Shell pyriform ; spine moderate; body- whorl ventricose ; base obtuse, emarginate ; lips smooth (fig. 71. c). undatura. En. M. 399. f. 1. lineatum. Ib. 400. f. 8. ? leevigatum. Ib. 400. f. 1 . f papillosum. Ib. 400. f. 2. TROCHIA Sw. Shape intermediate between Purpura and Buccinum ; whorls separated by a deep groove ; inner lip, when young, depressed, when adult, thick- ened, convex, and striated ; basal canal very small, sulcata. En. Meth. 422. f. 4. TRITONIDEA \ Sw. Shell bucciniform, but the basal half is narrowed, and the middle more or less ventricose ; spire and aperture equal. Pillar at the base with two or three obtuse and very transverse plaits, not well defined ; outer lip internally crenated, and with * By this group, the MURICIDS: are connected with the STROMBID^ by means of the CeraUtue. f Probably an aberrant species of Leiodomus. j Mr. Gray has the merit of first publishing this intricate, but most natu- ral genus, which I had many years ago also determined. I should gladly have adopted his name, were it not that Pallia has been already given by Hiibner and Treitsch to a genus of lepidopterous insects. Mr. Gray has very happily determined what is certainly its true station in the natural system, — that is, intermediate between Triton and Buccinum. It is connected to Triton by T. clandestinnm, Ency. M£th. 433. fig. I. (fig. 64. p. 297.), which thus completes the circle of this family. PART II. TURBINELLID^E. 303 a superior siphon; inner lip wanting, or rudi- mentary. undosa. En. Me"th. 422. f. 5. (Aberrant.) torulosa. Ib. 428. f. 3. aculeiformis. Ib. 426. f. 3. maculosa. Ib. 4OO. f. 7. articulata. En. M. 426. f. 1. FAMILY 2. TURBINELLIDJE. Base of the shell produced into a long channel ; the spire generally short ; the pillar often toothed ; outer lip thin. SUB-FAM. 1. TURBINELLIN^:. Spire short, the tip papillary ; middle or base of the inner lip plaited ; channel lengthened. TURBINELLA Lam. Shell ponderous, smooth, or slightly nodulous ; spire short, papillary ; pillar with strong plaits in the middle, (fig. 72. a.) rapa. En. Meth. 431. fez's, f. 1. pyrum. Chem f. 1697, 1698. FASCIOLARIA Lam. Fusiform, ventricose ; spire and aperture of equal length, the former attenuated and 304 SHELLS AND SHELL-FISH. PART II. acute ; outer lip crenated ; base of the pillar with one or two sharp folds, (fig. 72. d.) F. tulipa. En.Meth. 431. f. 2. trapezium. Ib. 431. f. 3. PYRELLA Sw. Pyriform ; spire very short, papillary ; channel lengthened; inner lip flattened, elevated, smooth ; pillar with a single sharp fold at the base. P. spirilla. Zool. 111. 1st series. En. Meth. 437. f. 4. CLAVILITHES Sw. Unequally fusiform, the body-whorl and spire being conic, and the canal suddenly con- tracted and attenuated ; terminal whorls papillary ; inner lip thick; pillar smooth. Fossil only. (fig. 72. &.) longaevus. En. M. 425. f. 3. Noae. En. Meth. 425. f. 5. clavellatus. Ib. f. 2. ponderosus Sw. Ib. f. 4. SUB-FAM. 2. SCOLYMIN^E. Spire more produced, the tip always acute; surface rough ; canal short ; pillar plaited. PLICATELLA* Sw. Fusiform ; the spire produced ; pil- lar with two or three obtuse, basal, transverse folds. polyzona. En. M. 423. f. 1. rustica. Mart. 120. f. 1104. cingulifera. Ib. 429. f. 1. triserialis. Lam. No. 21. carinifera. Ib. 423. f. 3. ocellata. Mart. 124. f. 1 160. infundibulum. Ib. 424. f. 2. variolosa. Lam. No. 22. craticulata. Ib. 429. f. 3. tuberculata. Grif.Cuv.30.f.3. lineata. Ib. 429. f. 4. turbinelloides. Ib. 25. f. 1. nassatula. Lam. No. 20. filosa. En. Meth. 429. f. 5. SCOLYMUS Sw. Sub-fusiform, armed with foliated spires ; spire shorter ; pillar with distinct plaits in the middle. cornigerus. Chem.f. 1725-6. capitellum. En. M6th. 431. pugellaris. En. M. 401. Us*, 3. bis *, f. 4. globulus. Ib. f. 2. umbilicaris. Ib. f. 1. a — c. rhinoceros. Chem. f. 1407-8. mitis. Lam. No. 10. p. 106. ceramica. Mart. 99. f. 943. * Polygonum of some writers; but that is a common and well-known botanical genus of Linnaeus, and cannot therefore be again applied. PART II. SCOLYMIN-SJ. EBURNIN.E. 305 CANCELLARIA Lam. Shell turbinate, scabrous,, generally reticulated j body- whorl ventricose ; spire and aper- ture nearly equal ; base obtuse ; pillar with distinct basal plaits ; aperture rather effuse ; the canal almost obsolete. C. reticulata. En. Meth. 375. f. 3. lobata Sw. (fig. 72. /. ) RHINODOMUS Sw. No internal groove ; shell clavate j the spire longer than, or equal with, the aperture ; the whorls with ridges or longitudinal varices, and ren- dered hispid by transverse grooves ; inner lip want- ing ; pillar with a terminal fold ; aperture striated ; outer lip with a basal sinus.* R. senticosus. Chem. tab. 193. f. 1864—1866. POLYTROPA Sw. I Bucciniform ; but the base narrowed, and ending in a straight and contracted, but rather short, channel j spire longer or as long as the aper- ture ; exterior folliculated or tuberculated ; inner lip flattened, as in Purpura; basal notch small, oblique ; no internal channel. crispata. En. Meth. 41 9 f. 2. imbricata. Mart. 1 22. f. 1 124. Chem. 187. f. 1802. ? rugosa. Chem. f. 1473-4. lapilla. Pennant, pi. 72. f.89. SUB-FAM. 3. EBURNIN^:. Shell generally grooved round the suture ; body- whorl ventricose ; spire rather longer than the aperture ; the base obtuse, and almost entire ; inner lip much thick- ened ; outer lip sinuated. CYLLENE Gray. Small ; shape of Harpa and Harpula ; shell longitudinally ribbed,, and sub-coronated with * Analogous to Nassa; but the inner lip is not developed, and there is not a superior or internal canal . it likewise represents Leiodomus by its animal, Scalaria by its varices, and Terebra by it spire. There are several species with shorter spires than senticosus. f This is an obvious representation of Purpura and Pyrula in this circle, and is connected to Plicatella by such aberrant species as have two or three obsolete tubercles at the base of the inner lip, and a row of others, more distinct, on the opposite side ; but even in these the pillar is always de- pressed, and the channel short. These species are chiefly from the Northern and Southern Oceans. They are at once distinguished from the Purpurce by having no internal channel at the top of the aperture. X 306 SHELLS AND SHELL-FISH. PART 11. tubercles, sometimes cancellated; aperture striated within, rather effuse, longer than the spire, which is acute ; inner lip large, vitreous, spreading ; the base finely striated ; outer lip with a slight sinus at the base, as in Rhinodomus; no internal groove; the suture sometimes channeled and polished. C. Owenii. Griff. Cuv. p. 41. f. 2. STRUTHIOLARIA Lam. Spire turreted ; outer lip con- siderably sinuated ; inner lip thick, spreading ; the pillar turned inwards ; the basal notch nearly obso- lete, nodulosa. En. M. 431. f. 1, crenulata. Astrol. pi. Sl.f.8,9. EBURNA Lam. Smooth ; sutures gene- j^ '3 rally grooved j spire and aperture about equal ; inner lip very thick, partly con- cealing the umbilicus, and with an up- per internal groove ; outer lip thin, slightly sinuated ; basal notch oblique, small, (fig. 73.) E.spirata. En.Meth.401.f.2. pacifica. En. Meth. 401. f.4. PSEUDOLIVA Sto. Shell thick, oval, oliviform, ventricose ; spire very short, acute ; base with two parallel grooves, one of which forms a notch at the base of the outer lip ; suture slightly channeled ; inner lip very thick, and turning inwards ; aperture with an internal canal. Connects the TURBINELLIDJE with the VOLUTID.E. P. plumbea. Chem. 188. f. 1806, 1807. (fig. 3. p. 82.) LATIAXIS Sw. Shell sub-pyriform, turbinate, and the whorls detached, as if distorted ; but the spire flattened at the summit ; whorls angulated, arid cari- nated, with a fimbriated undulate ridge ; pillar none ; umbilicus excessively large and deep.; aperture an- gular ; the basal notch nearly obsolete.* P. Ma was. Griff. Cuv. pi. 25. f. 4. * This singular shell I regard as the representation of Scalaria, Verme- tus, &c. in the present; group, and as opening a passage to the Pyrulitue by PART II. PYRULIN^E. 307 SUB-FAM. 4. PYRULINJE. Shell pyriform ; the base more or less produced ; the spire short and typically flattened ; inner lip convex, and perfectly smooth. * RAPELLA Sw. Shell ventricose, generally thin, almost globose ; the base suddenly contracted, and forming a short canal, the channel almost obsolete ; umbilicus large, partly concealed by the inner lip. R. papyracia. En. Meth. 436. f. 1. FICULA Sw. Shell thin, pyriform ; the base lengthened into an elongated channel; the upper part ventricose; spire very small, depressed ; inner lip wanting, (fig. 74.) ficus. En. Meth.431. caudata. En. Meth. f. 1. 436.f.l.6,c. PYRULA Lam. Shell strong, pyriform, solid, coronated with spines or tubercles ; the base lengthened into a long channel ; spire very short, but a little elevated and pointed ; inner lip wanting. P. perversa. En. Meth. 433. f. 4. CUMA Humphrey. Sub-fusiform ; spire and base equal in length ; inner lip with a central fold. C. sulcata Sw. (See fig. 4. p. 87.) MYRISTICA Sw. Sub-pyriform ; spire strong, spiny, or tuber cula ted, nearly as long as the base ; um- bilicus either partially or entirely concealed ; inner lip vitreous, thin ; the outer with an internal and ascending canal ; the basal channel wide. tiippocastanea. En. M. 432. melongena. En. Meth. 435. f. 4. f. 3. lineata. Ib. f. 5. nodosa. Chem. 1564-5. means of Rapella. I know it, however, only from the figures above quoted. Mr. Gray's description is confined to these words : " Shell deformed, white ; from China." It is obviously related to Rapella ; while, in its large umbili- cus and nearly obsolete notch, it has a greater resemblance to Eburna than to any other genus I am acquainted with. * Except in Cuma, where there is a central fold. x 2 308 SHELLS AND SHELL-FISH. I ART II. SUB-FAM. 5. FUSING. — Spindle- Shells. Shells generally fusiform and slender ; the base elon- gated ; the spire lengthened and acute ; pillar smooth ; outer lip thin. HEMIFUSUS Sw. Unequally fusiform, the spire being shorter than the aperture ; shell ponderous,, coronated with compressed spines ; an internal and ascending canal at the top of the aperture. colossus. En. M^th. 427. f. 2. morio. En. M£th.430. f.3,4. pyrulaceus. Ib. 429. f. 6. carnaria. Ib. 434. f. 3. coronatus. Ib. 430. f. 2. cochlidium. Ib. 434. f. 2. CHRYSODOMTJS Sw. Bucciniform, but the base pro- duced into a channel shorter than the spire ; whorls ventricose ; smooth, or nearly so.; outer lip thin ; inner lip obsolete. dispectus. Ency. M. 26. f. 4. sulcatus. En. Meth. 424. f. 3. argyrostomus. Ib.426.f.5. lignarius. Ib. 424. f. 6. Fusus Lam. Shell long, slender ; both extremities much produced : spire attenuated, turreted, and of nearly equal length with the aperture. Syracusanus. En. M.423. f.6. tuberculatus. En. M . 423.f.'4. torulosus. Ib. f. 4. aciculatus. Ib. 425. f. 8. incrassatus. Ib. 5. longicauda. Ib. 423. f. 2. LEIOSTOMA Sw. Equally fusiform, but ventricose in the middle ; shell entirely smooth, almost polished ; in- ner lip thickened and vitreous ; base of the pillar very straight. Fossil only. (fig. 75.) L. bulbiformis. En. Meth. 428. f. 1. STBEPSIDURA Sw. Equally fusiform, but the basal portion of the pillar turned outwardly, with a sharp fold at the base of the aperture ; shell costated and sub-coronated ; body- whorl ventricose. Fossil only. S. costata. Sw. En. Meth. 428. f. 2. (Fusus ficulneus Lam.) PART II. STROMBINjE. 309 FAMILY 3. STROMBID^. Wing-Shells. Outer lip dilated, or thickened internally, or detached from the preceding whorl by a sinus ; operculum small. SUBFAM. 1. STROMBIN^E. Outer lip considerably dilated, but never toothed ; spire rarely longer than the aperture, with a sinus near the base. APHORRAIS Da Costa, (fig. 76. a.) Spire longer than the aperture ; outer lip dilated into finger- like pro- cesses ; base produced, compressed, with a slender grooved channel in the middle, but no distinct lobe. A. pes-pelicani. Mart. 85. f. 848—850. PTEROCERAS Lam. (fig. 77.) Spire short; outer lip considerably di- lated, ascending and attached to the spire, in general divided into linear processes; basal lobe inflexed, toothed ; channel long. P.truncatus.Chem. latissimus Sw. Pi. 159. Mart. 83. f. laciniatus. Ex. 835. Conch. 46. purpuratus Sw. Chem. 158. f. Chem. 157. f. 1506, 1507. 1494, 1495. x 3 310 SHELLS AND SHELL -FISH. PART II. Callus. Mart. f. 841, 842. Goliathus. Chem. 195. B. inermis Sw. Bligh, Cat. gigas. Mart. 80. f. 824. accipitrinus. Ib. 81. f. 829. STROMBUS Linn. (fig. 76. &) Outer lip entire ; the mar- gin not inflected, with a deep sinus near the base, and the upper part not ascending to the top of the spire ; basal lobe rarely inflexed, and never toothed. Pacificus Sw. Chem. f. 1485, tricornis. En. Meth. 401. f. 1. 1486. Ex. Conch, pi. 17. melanostomus Sw. Ib. f. 1487-8. Ib. pi. 17. Auris-Dianae. Mart. f. 838-9. Lamarckii. Gray ? STROMBIDEA Sw. Outer lip angulated, but not dilated, or detached from the preceding whorl ; upper sinus obsolete, or entirely wanting ; the lower distinct. urceus. Mart. 78. f. 803. tridentata. Chem. f. 1503. plicata. En. M. 408. f. 2. ei-ythrostoma. Ib. f. 1874. mutabilis. Mart. 78. f. 807. dubia Sw. P. Mag.61. p. 377. ROSTELLARIA Lam. (fig. 76. c, d, e.) An ascending siphon, formed by a groove thickened on each side, which extends upwards on the spire ; outer lip various, but not sinuated at the base, curvirostris. En. Me"th. 411. columbata. En. Meth. 411. f.2. (fig. 16. e.) fissurella. Ib. f. 3. (fig. 76. d. ) cancellata. Ib. 408. f. 5. canalis. Ib. 409. f. 4. decussata. Sow. Gen. f. 8. rectirostris. Nat. G. pi. 2. f.2. serrata Sw. Chem. 195. A. f. 1869. macroptera. Brander, f. 76. SUB-FAM. 2. CONINE. Cones. Shell coniform; the spire very short, pyramidical or truncate ; outer lip slightly detached above, but without a basal sinus. TEREBELLUM Lam. Cylindrical, smooth ; aperture effuse at the base; outer lip with an obsolete sinus ; spire either short or con- cealed. T. subulatum. En. Meth. 360. fig. 1 (fig. 78.) PART II. CONINE. 311 CORONAXIS Sw. Shell conical ; the summits of the whorls crowned with a single row of tubercles ; mouth of the animal entire. Coronaxis Sw. Spire truncate, scarcely raised above the margin of the body-whorl,, which is not convex. Bandanus Lam. Voy. d' Astrol. pi. 53. f. 7. Puncticulls Sw. Spire slightly elevated ; body-whorl convex near the upper margin ; aperture linear ; base deeply notched. P. arenatus Lam. Voy. d' Astrol. pi. 52. f. 8. Tuliparia Sw. Body- whorl ventricose ; the aperture effuse. nebulosa Sw. Ency. M. 322. f. 11. (Conus tidipa L.) Cylindrella Sw. Conic-cylindrical; spire elevated, and only slightly coronated on the upper whorls ; shell generally grooved. Asper. Chem. 181. f. 1745-7. Conilithes Sw. Conic; spire considerably elevated; the aperture linear. C. antediluvianus. Sow. Gen. f. 1. CONUS Linn. Shell conic ; the summit of the whorls smooth ; mouth of the animal laciniated. Conus Linn. Spire generally truncate, or only pointed at the summit ; margin of the body- whorl carinate. C. millepunctatus. En. Me'th. 323. f. .5. litteratus. Ib. 323. f. 1. (fig. 79.) eburneus. Ib. 324. f. 1,2. nobilis. Ib. 339. f. 7. virgo. Ib. 326. f. 5. miles. Ib. 329. f. 7. capitaneus. Ib. 327. f. 2. vulpinus. Ib. 326. f. 6. maldivus. Ib. 325. f. 6. generalis. Ib. 325. f. 2. 4. monile. Chem. 14O. f. 1301—1303. Dendroconus Sw. Shell heavy ; spire lightly elevated ; x 4 312 SHELLS AND SHELL-FISH. PART II. body whorl convex near the margin ; aperture linear, betulinus. En. Meth. 338. franciscanus. E. M. 337. f.5. f. 7. striatus. Ib. 340. f. 1. figulinus. Ib. 332. f. 2. gubernator. Ib. 340. f. 5. quercinus. Ib. 332. f. 6. nimbosus. Ib. 341. f. 5. Textilla Sw. Spire elevated, concave; body- whorl ventricose ; the aperture effuse at the base ; shell always smooth. communis. En. M. 346. f. ammiralis. E. M.325. f. 1 — 9. 1 — 5. bullatus. Chem. f. 1315 — 6. auratus. Ib. 343. f. 1. pyramidalis. En. Meth. 347. rubiginosus. Ib. 344. f. 1,2. f. 5. Theliconus Sw. Shell narrow, nearly cylindrical, gene- rally grooved transversely; spire elevated, thick, convex, obtuse ; aperture linear, nussatella. Sow. Gen. f. 7. Terebra. Sow. Gen. f. 6. Leptoconus Sw. Shell light, conic, sometimes striated ; spire elevated, acute, concave ; the basal whorl cari- nated, detached, and sinuated above, and contracted near the suture. grandis. Sow. Gen. f. 2. duplicatus. Sow. Gen. f. 5. amadis. Chem. f. 1322-3. Australis. Ib. f. 4.* CONELLA Sw. Shell small, conic ; spire elevated, smooth ; the outer lip advancing a little up the spire ; aperture linear ; inner lip smooth ; outer lip striated within, picata Sw. (fig. 17. a, p. 151.) CONORBIS Sw. Conic, but resembling a Pleurotoma : spire conic, considerably elevated; outer lip with a deep sinus above. C. Dormiter. Sow. Gen. f. 8. SUB-FAM. 3. COLUMBELLIN^. Shell small ; outer lip considerably thickened within, where the margin is invariably either toothed or striated ; the top gibbous, the margin generally inflexed ; inner * Passing into Nussatella. PART II. COLUMBELLIN^:. 313 lip doubly toothed, i. e. internally and externally j aperture narrow, generally ringent ; operculum minute. CONIDEA Sw. Mitra -shaped, fusiform ; spire equal or longer than the aperture ; the whorls tumid ; outer lip slightly gibbous above, contracted below j margin not inflected ; striated within ; inner lip terminating in an elevated ridge, but with the teeth obsolete. C. semipunctata. (Columbella Lam.) Mart. 44. f. 465,466. COLUMBELLA Lam. Subfusiform ; spire shorter than the aperture ; outer lip gibbous, inflected, sinuated, broad, and thickest in the middle, crenated or toothed its entire length ; aperture contracted ; inner lip with granular teeth. C. mercatoria. Mart. pi. 44. 452 — 458. PUSIOSTOMA Sw. General form of Columbella ; but the outer lip is only toothed in the middle, where it is greatly thickened ; inner lip convex between the gra- nular teeth, (fig. 7 2. g, h.) punctata. En. M. 374. f. 4. fulgurans. Lam.* mendicaria. Ib. 375. f. 10. turturina. En. M. 384. f. 2. CBASSISPIRA Sw. Small, subclavate, tuberculated : spire thick, lengthened j outer lip with a slight sinus above, and thickened internally at the top and bottom ; top of the inner lip with a thick pad j basal channel but slightly defined, (fig. 17. a.) Pleurotoma Botta; Auct. C. fasciata Sw. (fig. 17. d, p. 151.) NITIDELLA Sw. Bucciniform \ small, ovate, smooth, glassy ; aperture effuse ; outer lip slightly thickened, faintly inflexed, and generally striated internally ; inner lip somewhat flattened above ; base of the pillar with one or two slight internal folds, or a single an- gular projection, (fig. \l.e.) Columbella nitida Lam. (fig.ll. c, p. 151.) * Lamarck erroneously cites the Ency. Meth. 574. fig. 7. for this species, as that represents one of his Mitres. 314 SHELLS AND SHELL-FISH. PART II. SUB-FAM. 4. PLEUROTOMIN^E. Shell turreted, subfusiform ; the base channeled, and often much produced ; outer lip never thickened, but detached at the top -from the whorl by a slit or sinus.* BRACHYTOMA f Sw. Subfusiform ; resembling a small Strombus or Fusus ; spire and aperture of equal length ; channel short ; outer lip slightly ascending, and forming a short canal ; sinus very small, and nearly semi-circular ; inner lip thickened above. strombiformis. Sow. Man. castanea Sw< Chem. f. 1831, f. 381. 1482. PLEUROTOMA Lam. Fusiform, turreted ; channel lengthened, and nearly as long as the spire ; the slit long and narrow ; inner lip wanting. P. virgo. En. Meth. 439. Babylonica. Ib. f. 1. f. 2. Javanica. Ib. f. 3. CLAVATULA Sw. Spire clavate, very long, turreted; channel short ; inner lip wanting. sulcata Sw. Chem. 190. f. 1829. CLAVICANTHA Sw. Thick, sub-fusiform ; the surface rugose, and the whorls sub-coronated ; channel short ; slit assuming the form of a short broad sinus. C. imperialis. En. Meth. conica. E. M. 439. f. 9. 440. echinata. Ib. 439. f. 8. spirata. Ib. 440. f. 5. auriculifera. Ib. f. 10. TOMELLA Sw. Fusiform, smooth ; the spire of very few whorls, and not longer than the channel ; inner lip with a thick callosity at the top ; the slit short and wide. lineata. En. Meth. 44O. f. 2. filosa. En. Meth. 440. f. 6. clavicularis. Ib. f. 4. lineolata. Ib. f. 11. * In the two typical groups, the'notch is a long slit ; in the three aberrant genera, it forms a wide but short sinus. f The aberrant species of this genus connects the sub-family with the Columbellince by means of Crassispira, They are mostly small and rare shells. PART II. CEBITHIN-ffi. 315 SuB-rAM. 5. CERITHIN,£. Shell clavate, generally mucronate ; the spire very long ; the outer lip considerably dilated ; the base either trun- cate, or forming a short recurved channel. POTOMIS Brong. Fluviatile ? covered with a brown epidermis : whorls coronated, and armed with spines ; aperture almost entire, the notch being slightly de- veloped ; top of the outer lip with an obsolete sinus, muricata. Sow. Man. 377.* granulata. En. M. 442. f.4. PIRENA Lam. Fluviatile ; smooth ; outer lip much dilated, with a deep narrow slit on the upper part; base widely notched; inner lip entire and thickened, t P. terebralis. Sow. Man. f. 316. (fig. 80.) *TEREBRALIA Sw. Outer lip much dilated, generally uniting at its base to the inner lip, leaving a round perforation at the base of the pillar ; channel truncate ; operculum round. palustre. Mart. f. 1472. heteroclites. Lam. No. 24. sulcatum. En. M.442. f. 2. telescopium. Voy. Ast. pi. 55. Ebenium. Ib. 442. f. 1. f. 4—6. RHINOCLAVIS Sw. Channel curved backwards in an erect position ; inner lip very thick, with a tumid margin ; pillar generally with a central plait ; oper- culum ear- shaped. lineatum. En. M. 443. f. 3. obeliscus. En. Meth.^S.f. 4. vertagus. Ib. f. 2. aluco. Ib. f. 5. (Aberrant.) subulatum. Lam. No. 23. semi-granosum. Ib. 443.f. 1. fasciatum. Mart. 157. f. 1481. asperum. Mart. 157. f. 1483. CERITHIUM Lam. Channel short, nearly straight ; pillar smooth ; inner lip thickened only at the top, where * Connecting this with the last sub-family by means of Clavicantha. t Representing Pleurotoma. 316 SHELLS AND SHELL-FISH. PART II. it forms a short internal channel ; operculum ear- shaped. nodulosum. En. Me"th. 442. tuberculatum. Mart. 157. f. 3. f. 1490. FAMILY 4. VOLUTID^. Shell destitute of a channel j the base truncated and notched ; the pillar marked with folds or plaits ; oper- culum none. SUB-FAM. 1. VOLUTIN^:. True Volutes. Spire shorter than the aperture, which is never striated; pillar with distinct plaits., the upper ones the shortest ; tip of the spire papillary.* (fig. 81.) VOLUTA Linn. Shell large, ventricose ; the spire ex- tremely short, very obtuse, and papillary ; the ter- minal whorls, where they exist, being smooth and un sculptured. 1. Turbinelliform type. Shell melon- shaped; spire very * Except in Volutilithes, 'which wants the three last characters, — the plaits.being faint, the tip of the spire acute, and the lower plaits the longest. PART II. VOLUTIN-E. 31? short, sometimes nearly obsolete, (fig. 81. 6.) diadema. En. M. 388. f. 2. armata. Ib. 388. f. 1. tessellata. Mart. f. 781. ^thiopica. En. M. 388. f. 3. melo. Ib. 389. f. 1. Neptuni. Ib. 386. f. 1. Cymbium. Ib. f. 3. proboscidalis. Ib. 389. f. 2. Olla. Ib. 385. f. 2. rubiginosa. Ex. Conch. 28. porcina. En. M. 386. f. 2. 2. Muriciform type. Shell heavy, less ventricose, co- ronated with cylindrical or vaulted spines ; spire more produced. marmorata. Ex. Conch, pi. 1 . chrysostoma. Ib. pi. 45. imperialis. En. Meth. 382. 1. 3. Strombiform type. Outer lip dilated, and angulated above. scapha. En. Meth. 391. Exotic Conchology, pl.48. 4. Ancilliform type. Aper- ture very wide ; spire pointed. angulata Sw. Ex. Conch, pi. 3, 4. 5. Marginelliform type. Shell partially polished; ventricose. magnifica. Chem. 174, 175. fulgetrum. Sow. Tank. C. CYMBIOLA Sw. Spire more produced, but not more than half as long as the aperture ; the terminal whorls regular and sculptured ; plaits on the pillar four. (fig. 81. «.) 1. Type? Ancilla. En. Meth. pacinca. Chem. 178. f. 1713, 385. f. 3. 1714. Ex. Conch, pi. 14. magellanica. Ib. f. 1. 2. Vespertilio. En. M£th. 378. f. 2. nivosa. Ex. Conch, pi. 5. festiva. ? Lam. No. 42. 3. Mitis. Ex. Conch, pi. 40. 4. Braziliana. Chem. 176. f. 1695, 1696. HARPULA Sw. Spire developed as in the last, but the tip is generally more slender, and the plaits are numerous. 1. Vexillum. En. Meth. 331. f. 1. (fig. 82.) Lapponica. Ib. 381. f. 3. 2. Hebrsea. En. Meth. 380. f. 2. musica. Ib. 380. f. 1. thiarella. Ib. 380. f. 2. carneolata. Mart. 96. 930. Guiniaca. Chem. 178. f. 1717, 1718. fulva. En. Meth. 382. f. 3, sulcata. Chem. 149. f. 1403. Levigata. En. Meth. 379.f. 2. nodulosa. Lam. No. 31. polyzonalis. Ib. 379. f. 1. 318 SHELLS AND SHELL-FISH. PART II. 3. fulminata. En. M. 381.f. 2. 5. Lyriformis. Zool. 111. i. 54. 4. bullata. Zool. 111. ii. pi. 15. concinna. Brod. Z. P. iv. 43. nucleus. Lam. No. 44. mitrseformis. Lam. No. 43. VOLUTILITHES Sw. Spire acutely pointed ; plates gene- rally faint, sometimes obsolete, (fig. 81. e.) 1. spinosa. En. M. 392. f. 6. 4. Cithara. En. M. 384. f. I. S.musicalis. En. M. 392.f. 4. 5. bicorona. En. M. 384. f. 6. muricina. Ib. 383. f. 1. crenulata. Ib. f. 5. 3. rarispina. En. M. 384. f. 2. costaria. Ib. 383. f. labrella. Ib. 384. f. 3. ty™. Ib. f. 6. SCAPHELLA Sw. Shell smooth, almost polished; outer lip thickened internally ; suture enamelled ; lower plaits the smallest; apex of the spire various, (fig. 81. c.) l.fusiformis Sw. Bligh, Cat. Junonia. Ex. Conch, pi. 33. 2. undulata. Ex. Conch, pi. 27. 3. stromboides. (fig. 12. a, volvacia. Chem.f. 1339. 6. p. 123.) Zebra Sw. (fig. 81. c.) 5. papillosa Sw. Sow. Gen. SUB-FAM. 2. MITRAN.E. Spire produced, acute, generally as long* or longer than the aperture ; plaits 4 — 5, the lower smallest. t MITBA. No internal channel or groove at the upper extremity of the aperture ; outer lip curved from its two extremities ; the base of the aperture not contracted, the interior always smooth ; spire lengthened, acute ; shell without co- ronating tubercles, but not polished. Re- presenting the Volutes and TurUnellidte. Mitra Sw. Shell entirely smooth, or with the sutures very slightly crenated ; aper- ture very effuse at the base. (fig. 83.) episcopalis. En. M. 369. f. 2. ambigua. Zool. 111. ii. 30. f. 2. pertusa. Ib. 369. f. 1. 3. fulva. Ib. f. 3. versicolor. Martyn, 1. f. 23. Terebralis. En. M. 369. f. 5. nivosa Sw. Bligh, Cat. lactea. Ib.^371. f. 2. * Except in Concehelix. f Except in some Mitreol.) Tiara Sw. Shell turreted, fusiform, costated, and semi-coronated ; spire and aperture of equal length ; internal striae slight or obsolete, (fig. 84. c.) ' virgo Linn, unfigured.* nodosa Sw. Ib. 373. f. 2. Regina. Chem. 151.f. 1444. plicaria. En. M. 373. f. 6. vittata. Zool. 111. i. lyrata. Ib. 373. f. 1. taeniata. En. M. 373. f. 7. Caffra. Ib. 373. f. 4. corrugata. Ib. f.8. (^.84.c.) simplicata. Ib. 373. f. 9. costellaris. Ib. f.3. (jfy.84.0.) melongina. Ib. 373. f. 9. vulpicula. Ib. 373. f. 5. foraminata. Zool. P. iii. 194. * I have once seen this beautiful shell, the rarest and most slender of this genus. 320 SHELLS AND SHELL-FISH. PART II. Costellaria Sw. Unequally fusiform ; the spire longer than the aperture ; body-whorl slightly ventricose, but suddenly contracted near the base ; internal striae distinct ; whorls convex, rarely angulated ; the ribs reaching to the suture, (fig. 84. d.) C. rigida. Zool. 111. 1st Series, pi. 29. Callithea Sw. Spire and aperture of nearly equal length ; internal' channel nearly obsolete ; shell with longi- tudinal linear ribs, crossed with transverse striae and bands ; base contracted, (fig. 84. e.) sanguisuga. En. Meth. 373. stigmataria. Chem. 151 . f. 1442, f. 10. • 1443. Cancilla Sw. General shape of the last ; but the whorls crossed by transverse linear ribs, or elevated ridges ; internal canal wanting ; plaits very oblique ; form slender ; outer lip thin. (fig. 84. &,) Isabella. Zool. 111. ii. pi. 50. sulcata. Ib. pi. 50. f. 2. Pusia Sw. Size very small ; spire thick, obtuse ; outer lip thickened, and often reflected ; aperture striated, with an internal canal. microzonis. En. Meth. 374. f. 8. MITREOLA Sw. Small ; unequally fusiform ; the base obtuse ; inner lip, typically, thickened, inflected, and either toothed or tuberculated ; plaits on the pillar distinct, the inferior largest ; tip of the spire some- PART II. OLIVIN^I. 321 times papillary; aperture without either striae or groove. monodonta. Zool. 111. ii. 128. f. 1. terebellum. Ib. f. 2. Sw. Small ; cylindrical or conic ; spire ge- nerally short and thick ; plaits on the pillar nu- merous ; exterior often decussated. C. conulus. En. Me"th. 382. f. 2. MITBELLA Sw.* Rather small; olive-shaped; ^ 85 unequally fusiform ; always smooth and polished, and sometimes covered with an epidermis ; base obtuse and effuse ; spire nearly or quite equal to the aperture ; plaits of the pillar few, oblique, and ex- tending beyond the aperture, which is smooth internally. (M. bicolor,/^. 85.) ocellata. Zl. 111. v. pi. 54. f. 2. olivaefonnis. Zool. 111. i. pi. 48. fissurata. En. M. 371. f. 1. ii . 54. f. 3. casta. Zool. 111. i. pi. 48. fusca. Ib. ii. pi. 54. f. 1. bicolor. Ib.ii. 19. f.2. Ofy.85.) dactylus. En. M. 372. f. 5. olivaria. En. M. 371. f. 2. SUB-FAM. 3. OLIVIN^. Olivet. Shell smooth, highly polished ; spire very short ; the suture channeled; inner lip much thickened; plaits numerous, crowded, extending, in the typical genus, the whole length of the aperture, (fig. 86, 87.) LAMPRODOMA Sw. Mitriform ; spire pro- duced, conic; resembling Mitrella in shape, but the suture is channelled ; the aperture effuse at the base, contracted above ; lower half of the pillar with 6-7 plaits, volutella. Zool. 111. ii. series, pi. 40. f.l. (fig.S6.) OLIVA Lam. Cylindrical ; spire very short, pointed; pillar with numerous slender plaits ; aperture narrow; the base not effuse, (fig.&l. c.) O. maura. Sow. Man. f. 457. T 322 SHELLS AND SHELL-FISH. PART II. SCAPHULA Sw. (fig. 87- 6.) Spire very short, thick, ob- tuse, and not defined ; aperture very wide, with only two or three oblique plaits at the base. S. patula Sow. Tank. Cat. 2331. (6.) HIATULA Sw. (fig. 87. a.) General shape of Oliva ; but the upper part of the pillar is not thickened ; the lower tumid, and marked with a few oblique plaits ; the aperture wide, the base effuse. Lamarckii. Zl.Il.ii.p.78.f.l. maculosa. Ib. 78. f. 3. pallida. Ib. 78. f. 2. ? striata. Ib. pi. 40. f. 2. OLIVELLA^W.* (fig. 87- e.) Oliviform; spire (typically) rather produced ; the tip acute ; inner lip not thick- ened ; outer lip straight ; base of the pillar curved in- wards, and marked by two strong plaits ; upper plaits obsolete or wanting ; aperture effused at the base only. biplicata. Tank. Cat. 2332. eburnea. Zool. 111. ii. 58. f.2. purpurata. Zl. 111. ii.. 58. f. 1. conoidalis Lam. No. 57. mutabilis Say. oryza Lam. No. 62. SUB-FAM. 4. ANCILLARINJE. Shell oliviform, highly polished ; aperture very effuse ; suture concealed by enamel; base with one or two * The union of the Volutidce and the Turbinellidce is so intimately effected by Qlivella biplicata and Pseudolivaplumbea (see Jig. 3. p. 82.), that the two plaits on the pillar of the former shell alone separate the two families. 323 PART II. MARGINELLIN^E. strong grooves, which form a little tooth at the edge of the outer lip ; inner lip wanting ; base of the pillar thick, vitreous, obliquely striated, and turned outwards. ANCILLARIA Lam. The characters, at present, are those of the sub-family, as the genera have not been worked out. A. glabrata Sw. (fig. 88.) SUB-FAM. 5. MARGINELLINJE. Shell small; oval; spire short or concealed; outer lip, and often the inner, very much thickened and inflexed, with the inner margin tcrenated; pillar with distinct plaits ; the base with a wide, but not a deeply cleft notch. VOLUTELLA Sw. Bulliform ; ovate oblong ; spire either entirely or almost concealed ; pillar with four oblique plaits at the base ; aperture not striated ; outer lip smooth, thickened; inner lip wanting. (fig- 89.) V. bullata Chemn. 150. f. 1409-10. oblonga. Zool. 111. ii. pi. 44. f. 1 guttata. Ib. f. 2. PEBSICOLA Schum. General form of Volutella the spire always concealed ; plaitsnumerous, and extending nearly over the whole of the pillar; the aperture striated; inner lip thick ened, spreading. avellana. En. M. 377. f. 5. lineata. En.M. 377. maculata Sw. Ib. f. 3. f. 4. (fig. 9O.) GIBBER UL A Sw. Sub-oval; spire slightly prominent ; top of the outer lip dilated and gibbous ; base of the inner lip with plaits ; inner lip broad, spreading. G. zonata. En. Meth. 374. f. 6. MARGINELLA Lam. Oval ; spire slightly prominent ; Y 2 324 SHELLS AND SHELL-FISH. PART II. inner lip very much developed, and forming a tumid rim all round the aperture. M. lactea Sw. Sow. Gen. f. 3. 91 (ISABELLA Sw. Volutiform ; the spire more or less conic, and well developed ; pillar with basal plaits ; inner lip obsolete ; outer lip thick, toothed, or crenated ; rarely smooth.* (fig. 91.) P. ruffina Sw. En. Meth. nubicola. En. M. 377. f. 2. 377. f. 6. bifasciata. Ib. f. 8. Goodalli. Tan. Cat. 2151 a. limbata. .Ib. 376, f. 3. Faba. En. Meth. 377. f. 1. caerulescens. Ib. 376. f. 8. FAMILY 5. CYPR^EID^E. Cowries. Oval ; polished ; spire entirely concealed ; aperture as long as the shell, narrow, and open at each end ; outer lip generally thickened and inflected. SUB-FAM. l. Inner lip striated or toothed. CYPR^A Linn. Shell always entirely smooth ; the extremities of the aperture obtuse ; the teeth marginal, and not extending over the circumference of the lips. C. Arabiea. Sow. Man. f. 445, 446. caput-serpentis Lam. (Jig. 92.) PUSTULABIA Sw. Shell generally marked by elevated pustules ; aperture very narrow, and linear ; the ex- tremities more or less produced ; the teeth continued beyond, and frequently forming elevated striae across, the lips. P. cicercula. En. Meth. 355- globulus. (Aberrant.) En. f. 1. Meth. 356. f. 2. * M. ceerulescens Lam. (prunum Linn.) unites this type to Volutella. PART II. OVULINJE. 325 TRIVEA Gray. Shell marked with transverse, unin- terrupted, elevated lines, uniting with the teeth ; the aperture wide, and the extremities ohtuse ; inner lip with a thickened protuberance ; pillar concave within, coccinella. En. M. 356. f. 1. Pediculus Auct. CYPR^EDIA Sw. Cyprseform; the hase contracted; the body-whorl not flattened beneath ; shell cancel- lated ; aperture of equal breadth throughout j a few thickened, short teeth on the pillar ; lip at the base, which is not internally concave.* C. cancellata Sw. Sp. Nov. CypRjEovAf Gray. Cypraeform ;-teeth of the inner lip wanting, being represented by fine raised lines con- tinued on the back of the shell ; aperture rather effuse ; top of the outer lip much projecting. C. capensis. Sow. Man. f. algoensis Gray. ( Aberrant. ) 444. Sow. Man. f. 447. SUB-FAM. 2. OVULINJE Oviform ; smooth, polished ; the extremities of the aperture more or less produced ; inner lip without teeth. CYPR^ELLA Sw. Cypraeform ; inner lip thickened above into a point as long as the outer lip, the mar- ginal teeth of which are very regular ; a circular de- pressed line at each extremity. C. verrucosa. En. Meth. 357. f. 5. OVULA Lam. Oviform ; top of the outer lip elevated and produced beyond that of the inner, which is turned and much thickened ; both lips equal at their base, and slightly produced. O. ovum. En. Meth. 358. f. 1. BIROSTRA Sw. The two ends of the aperture suddenly *- Fossil only ; differing from Trivea in its contracted base, in the equsu lity of its aperture, and the equal convexity of the inner lip within, t Abbreviated from Cyprceovulum. This seems the strombiform type. Y 3 326 SHELLS AND SHELL-FISH. PART II. contracted and produced into two long beak-like pro- cesses ; aperture effuse ; the outer lip inflected, but not toothed. B. volva. En. Meth. 357. f. 3. CABINEA Sw. Oblong ; the extremities not produced ; aperture nearly straight,, almost central, contracted above, and very effuse below ; lips equal ; the outer slightly toothed. C. gibbosa. En. Meth. 357. f. 4. (fig. 93-) VOLVARIA Lam. Cylindrical ; lengthened ; the ex- tremities obtuse ; the surface sculptured ; base of the pillar with 3—5 distinct plaits ; outer lip crenated ; aperture linear ; fossil. V. concinna. Sow. Man. f. 439. (fig. 94. a.) OYLINDRELLA Sw. Cylindrical, narrow, and obtuse, as in Folvaria ; but the surface and outer lip are smooth, and there are no plaits on the pillar. C. alba Sw. (/0 SHELLS AND SHELL-FISH. PART II. Paludina Lam. Whorls inflated ; umbilicus open ; operculum horny ; aperture ovately round, elongata. Zool. 111. i. pi. 98. (fig. 101. 6.) unicolor. Ib. (c.) JVematura Benson.* Whorls slightly convex; aperture small, oblique, contracted ; operculum spiral, horny. Sow. Man. f. 305. MELADOMUS Sw. Spire pointed; aperture oval, re- versed, pointed, and contracted above ; umbilicus none ; operculum ? M. bulimoides.f Sw. Sp. Nov. SUB^FAM. MELANIAN.E. Shell spiral ; the spire always as long as, and generally much longer than, the aperture ; body-whorl small.J PALUDOMUS Sw. Shell oblong-globose, strong ; spire shorter than the aperture ; inner lip very thick. Paludomus. Shell smooth ; outer lip slightly spreading, the margin crenated ; inner lip very thick and ena- meled. India. P. globulosa. Griff. Cuv. xii. conica. Griff. Cuv. f. 5. pi. 14. f. 6. retusa. Ib. f. 9. Anculosa Say. Spire very short ; outer lip sinuated, thin ; top of the inner lip thickened internally ; but obsolete in the middle, and flat at the base. America, praerosa and monodontoides Say. Sow. Man. 314. Hemimitra Sw. Resembling Paludomus:, but the whorls are coronated. India. H. retusa. Sw. Sp. Nov. MELANIA. Shell elongated, spiral; the aperture oval, entire ; the outer lip dilated at its base. * I do not know this type. •f Entirely brownish black. The shape and size similar to Bulimus citrinus ; but the outer lip thin. Inhabits China ? I Except in Paludomus. which blends into Meladomus. and thus unites this with the last sub-family. PART II. MELANIAN.fi. 341 Melacantha Sw. Spire and aperture nearly of equal length ; the whorls coronated with spines; inner lip very thin. M. amarula Sie. Zool. 111. ii. pi. 29. f. 1. (fig. 102. a.) setosa Sw. Ib. ii. f. 2. Melania Lam. Subulate and elon- 102 gated; inner lip wanting, (fig. 102. 6.) M. quadriseriata. Griff. Cuv. 14. f. 3. Potadoma Sw.* General characters of Melania; but the outer lip is hardly dilated, and the top of the inner lip is internally thickened. P. Frethii. Griff. Cuv. 14. f. 2. laevis. Ib. 14 f. 8. Hemisinus Sw. General shape of Melania ; but the base of the aperture is contracted and emarginate ; outer lip crenated. H. lineolata. Griff. Cuv. xii. pi. 13. f. 4. Melanella Sw Obovate ; spire scarcely longer than the aperture, which is entire ; inner J;p much thick- ened its whole extent, t MELANOPSIS Lam. General form of Melania; but the spire shorter, and the base of the aperture notched. Melafusus Sw. Sub-fusiform; the base contracted, and the aperture and spire nearly equal. 1 Species, America. Melanopsis Lam. Obovate ; the base obtuse ; spire pointed, acute ; inner lip greatly thick- ened, particularly at its upper part, and in- ternally ; suture compressed and flattened, buccinoides Lam. (fig. 103.) Melanithes Sw. Habit of Melania ; but the spire is obtuse, and the suture prominent. Fe'rus. Moll. Melanop. pi. 2. f. 1 1, 12, 13., pi. 1. f. 5. 7. 16. * I suspect that the true distinction of this second type of Melania will rest on the deciduous nature of the spire. t This type, which represents Planaxis,' unites on the other side to Me- lacantha. I have a small species, but know not whether it is described.. z 3 342 SHELLS AND SHELL-FISH. PART II. Canthidomus Sw. Spire generally short; whorls co- ronated with spines, or marked with longitudinal ribs ; base obtuse. FeVus. Moll. Melanop. pi. 2. costata. Sow. Gen. f. 3. f. 9. 10.,pl.l. 13,14,15. Melatoma Sw. Fusiform ; longitudinally - 1Q4 ribbed ; a deep sinus at the top of the outer lip ; base contracted, channel wide.* M. costata Sw. (fig. 104.) CERITHIDEA. Clavate ; cerithiform ; aper- ture sub-emarginate. Triphorus Desh. Shell small, slender, sub- cylindrical ; spire long, of numerous whorls ; aperture sinistral ; outer lip re- flected over and united to the inner, but leaving a circular opening. T. costata. Sow. Gen. f. 375. Cerithidea Sw. Shell light ; decollated ; outer lip semi- circular, dilated by a flattened border; aperture emarginate. C. lineolata. Griff. Cuv. 14. f. 4. fragilis. Ib. 32. f. 12. Ceriphasia Sw. Cerithiform ; outer lip thin, dilated at the base ; aperture small, slightly emarginate, without any internal groove ; inner lip thin. C. sulcata Sw. (fig. 38. p. 204.) PLANAXIS. Animal marine ; shell obovate ; inner lip much thickened above ; pillar flattened ; the base with a small notch or sinus. P. semisulcatus Lam. Sow. Gen. f. 3. SUB-FAM: TURBINE. Animal marine ; shell solid, spiral ; aperture round or oval, entire, sometimes toothed.^ * Representing Pleurotoma, and united to Melctfusus. f Except certain types of Melamptis, which appear amphibious ; and others which have plaits and teeth on the aperture. PART II. TURBIN^B. 343 SCALARIA Lam. Shell turreted, marked with longi- tudinal rihs ; aperture circular, entire, pretiosa. En. Meth. 481. f. 1. TURRITELLA. Shell turreted ; spire subulate, very long; umbilicus none. Rissoa Fremonville. Spire moderate, perpendicular, acute ; outer lip thickened ; aperture oval. R. reticulata. Sow. Man. 346. Turritella Lam. Aperture round, entire ; outer lip thin. T. duplicata. En. Meth. 449. f. 1. Eulima Desh. Shell smooth, polished ; spire distorted, acute j outer lip thin, dilated in the middle. E. labiosa. Sow. Man. f. 347. marmorata. Ib. f. 348. Pyramidella Lam. Shell smooth, polished ; outer lip thin ; base of the pillar produced, and marked with distinct plaits. P. terebellum. Sow. Man. f. 342. Truncatetta Risso. Cylindrical ; turreted ; the apex very obtuse ; aperture oval, small, entire ; the lips united. T. laevigata Risso. Drap. costulata. Zool. 111. pi. 13. pi. 1. f.31. f. 13— 18. TURBO Linn.* Shell turbinate ; spire short, generally pointed, not longer than the aperture j inner lip flattened, broad. littoreus (the common winkle). Sow. Man. 363. (fig. 109. e.) Tornatella^ Lam. Animal marine ; shell solid ; body- whorl cylindrical ; spire pyramidical, pointed ; aper- ture contracted above; effuse beneath ; base of the pillar with two strong plaits ; outer lip very thin. T. fasciata. En. Meth. 452. f. 3. MELAMPUS. Amphibious Volutes. Obovate, or oval ; the spire generally short, and never longer than the * Tuba, Assiminea, and Monatigma, which may probably be sub-genera, I am not acquainted with ; and, as their animals appear unknown, I am fearful of locating them incorrectly. •f- This sub-genus possibly unites TURBO to Melampus ; it is the only one which has that sort of colouring peculiar to marine shells. z 4 344 SHELLS AND SHELL-FISH. PART II. aperture ; outer lip thin, but thickened on the in- ternal margin ; one or both lips with distinct teeth or plaits ; animal with two tentacula, sessile eyes, but no operculum. Geovula Sw. Oval ; spire very short, tur- binated, cancellated, of many whorls ; apex obtuse ; outer lip thickened inter- nally; inner lip with a strong plait near the base. (fig. 105.) G. Midae. Griff. Cuv. 27. f. 8. Pedipes Adans. Shell smalJ, turbinate or sub-spiral j body- whorl ventricose ; aper- ture on both sides defended by several teeth and plaits. P. afra. Lowe, in Zool. Journ. v. pi. 12. f. 8 — 12. Scarabus Montf. Shell depressed ; spire as long as the aperture ; umbilicus partly open j both lips with plaits, and tuberculous teeth. S. imbrium. Sow. Man. f. 299. Melampus Montf. Oval, sub-coniform ; spire very short, obtuse ; aperture narrow ; inner lip thin, and striated internally ; pillar plaited, fasciatus. Gr. Cuv. 27. f. 13. exiguus .Lew. Z. J. v. 12. f. 6,7. Rhodostoma Sw. General form of Melampus and Tornatetta ; but the aperture is not striated, and the inner margin of the lip is broad, considerably thick- ened, and distinctly notched towards the top. coffea. Chem. 120. f. 1043. nucleus. Fer. Tab. Sys. 105. fabula. Fer. Tab. Sys. 1 05. 24. 26. SCISSURBLLA D' OrMg. Shell very small or minute ; he- liciform ; spire depressed ; aperture effuse ; outer lip with a narrow fissure or slit ; umbilicus open. S. elatior. Sow. Man. f. 340. FAMILY NATICIDJE. Shell globose, generally smooth ; spire minute, scarcely raised ; aperture large, semicircular. PART II. NATICIN-E. 345 SUB-FAM. 1. NATICIN.E. Sea Snails. Shell globose ; * inner lip smooth, not depressed. NATICA Lam. Operculum shelly ; shell globose ; ventricose ; umbilicus open, with a central gibbous ridge, or prominence. N. lineata. Mart. 186. f. millepunctata. Ib. 186. f. 1864, 1865. 1862, 1863. Naticella Guild. Operculum horny; shell globose, but generally depressed ; umbilicus nearly filled up with a vitreous deposition of the inner lip ; spire ob- tuse. ? N. aurantia. Mart. 189. f. 1934, 1935. Globularia Sw.f Shell not depressed, but the aperture very effuse ; base of the body-whorl with a thickened belt; apex of the spire acute ; recent and fossil, (fig. 106.) sigaretina Lam. Coq. Foss. 13. f, 1. patula. Ib. f. 2. depressa. Ib f. 3. acuminata. Ib. f. 4. spirata. Coq. Foss. 13. f. 7. fluctuata. Griff. Cuv. 1. f. 4. crossitana. Ib. f. 8. Mamillaria Sw. Shell oval, heavy ; spire very small, pointed ; inner lip considerably thickened at the top, and filling up a large umbilicus, placed near the base of the aperture ; aperture effuse. M. lactea Sw. Mart. 189. tumida Sw. Ib. 189. f. 1928 f. 1922, 1923. —1931. Sigaretus Auct. Oval, flattened, ear- shaped ; inner lip almost wanting ; umbilicus none. T. concavus. Lam. Hist. Nat. vi. 2. p. 208. * The arrangement of this group, from ignorance of the animals of the major part, is purely artificial, being founded only on the shells. f Globulus Sow. : altered, that the specific names may not be changed. 346 SHELLS AND SHELL-FISH. PART II. Naticaria Sw.* Oval ; convex above ; umbilicus small, open, placed very near the top of the aperture ; inner lip reflected, small, (fig. 107.) N. melanostoma. Mart. 189. f. 1926, 1927. cancellata Sw. Ib. 189. f. 1939. bifasciata. Griff. Cuv. 1. f. 2. Lacuna Turton. Turbinate ; thin ; spire very small, of two whorls j the general shape is like Natica, but the base is contracted; umbilicus close to the top of the aperture, with a groove running on the margin of the pillar, which is oblique ; operculum horny ; aperture effuse, semicir- cular, (fig. 108.) L. pallidula Turton. (fig. 108.) Leucotis Sw. Form of the shell intermediate between Sigaretus and Lacuna ; but there is no pillar ; umbi- licus large, pervious ; inner lip thin, slightly reflected at the top ; surface sculptured. Sigaretus cancellatus. Lam. Sys. vi. 2. p. 207. Chem. 165. f. 1596. 1597 SUB-FAM. ? NE RITDSLE. Nerits. Globose ; spire very small ; pillar oblique ; inner lip very broad, depressed, more or less flattened, and gene- rally toothed ; aperture semicircular. NEBITA Linn. Shell solid ; inner lip toothed or gra- nulated. N. peloronta. Mart. 192. f. polita. Mart. 193. f. 2002, 1977—1981. 2003. Neritopsis Gray. Aperture sub-orbicular ; pillar lip thickened above and below, with a wide notch in the middle. | N. granosa. Sow. Man. f. 331. * These are probably aberrant species, connecting Sigaretus with Ma- millaria; but, until the whole are better understood, I think it advisable they should be kept distinct. t Apparently related, by the shell, to Leucotis. PART II. TROCHID.E. 347 NERITINA Lam. General shape of Nerita ; but the outer lip is thin and smooth, the inner one rather convex and crenated ; surface smooth. N. meleagris. Chem. 124. f. 1088. a— i. Clithon Montf. Leach. General shape of Neritina ; but there is an obtuse lobe on the inner lip, the outer is dilated at its origin, and the whorls are armed with spires. C. corona. Chem. 124. f. 1083, 1084. Velotes Mont. Nearly orbicular; depressed; above convex ; beneath flat ; spire nearly obsolete ; inner lip toothed, as large as the aperture, which is semi- circular. V. perversa. Sow. Man. f. 326. Pileolus Cookson. Shell above patelliform ; spire in- ternal ; aperture beneath small, semilunar; outer lip margined ; inner crenated. P. plicatus. Sow. Man. f. 332. Navicella Lam. Somewhat patelliform ; oval ; convex above ; flat beneath ; aperture large ; inner lip nar- row, thin, assuming the form of a plate across one end of the under surface ; operculum shelly. * N. elliptica. Sow. Man. f. 323. FAMILY TROCHID^. d Unites the NaticicUe to the Haliotidce, by Crepidula. 348 SHELLS AND SHELL-FISH. PART II. Shell turbinate, mostly trochiform *, the substance almost always perlaceous ; outer lip never thickened ; aperture entire, closed by a shelly or horny operculum. SUB-FAM. SENECTIN^:. Snake Shells. Operculum round ; calcareous ; shell turbinate ; the basal whorl ventricose ; pillar always smooth ; aperture round, rarely oblique. SENECTUS Humph. Imperforate; the base produced into a broad flat lobe ; spire rather elevated and pointed ; the whorls convex ; aperture perfectly round ; not more oblique than Helix ; inner lip entirely wanting, (jig. 110.) imperialis. Mart. 180. f.1790. radiatus. Mart. f. 1788-9. marmoratus. E. M. 448. f. 1. margarltaceus. Ib. f. 1762. pethiolatus. Mart. f. 1777-8. Sprenglerianus. Ib.f. 1801-2. cornutus. Ib. 179. f. 1779-80. crenulatus. Ib. f. 1811-12. setosus. En. Meth. 448. f. 4. hippocastanum. Ib.f. 1807-10 argyrostomus. Mart. f. 1766. coronatus. En. M. 448. f. 2. chrysostomus. Ib. f. 1766. angulatus Sw. Sow. Gen. f. 8. MABMABOSTOMA Sw. Umbilicus deep ; spire of few whorls, much depressed, and obtuse ; inner lip ob- solete ; base even more produced than in Senectus, but never distinctly channeled. M. versicolor. Mart. 176. undulata. Chem. 169. f. f. 1740, 1741. 1640, 1641. DELPHINULA Lam. Turbinate ; spire depressed, the tip obtuse ; pillar almost entirely wanting ; the umbili- cus being large and pervious; exterior of the shell rough with tubercles or lamellar plates, (fig. 109« h.) torquata. Mart. Conch. 2.f. 71. laciniata. En. Meth. 451. lamellosa. Zool. J. v. p. 33 1 . f. 1 . CycLOCANTHAt Sw. Sub-depressed, trochiform; im- * Except Phasianella. t Resembles Tubicanthus, but the aperture is hardly perlaceous, the body-whorl not flattened beneath, or the mouth oblique. PART II. TBOCHIN^E. 349 perforate ; both sides compressed ; substance of the shell not perlaceous, but convex ; mouth slightly ob- lique ; lips united ; base not produced : doubtful type, stellaris. Mart. 164. f. 1553-4. calcar. En. M«hh. 451. f. 2. CIDABIS Sw. Perlaceous ; turbinate ; generally smooth ; the base not produced ; the inner lip not concave ; always imperforate ; aperture round, but oblique ; operculum very thick : representing Cattiostomus. sarmaticus. Mart. 179. pethiolatus. Mart. 183. f. f. 1777, 1778. 1826. smaragdus. En. M. 448. f. 3. pictus Sw. En. Meth. 448. E.coronatus. Sw. Chem. 165. f.5. f. 1585, 1586. ater Sw.* Sow. Gen. f. 7. SUB-FAM. TROCHIN^E. Trochus, or Top. Shell trochiform; the body-whorl more or less wide, and flattened beneath; the spire conical or pyramidical; aperture oval, wider than it is high ; operculum horny, f CANTHOBBIS. Operculum shelly; aperture very oblique, broad, and narrow ; the basal whorl much flattened ; pillar, in the typical examples, twisted : representing Cerithium. Tubicanthus Sw. Turbinate; aperture oval, effuse; very oblique; inner lip broad, concave, spreading, united to the outer lip; base of the pillar simple, blended with the circumference of the aperture.:): rugosus. Mart. 180. f. Tuber. Mart. 165. f. 1373. 1782—1785. Cookii. Ib. 163. f. 1540. caelatus. Ib. 162. f. 1536.1 imbricatus. Id. 162. f. 1531. Canthorbis Sw. Suns. Nearly disk-shaped : spire but slightly raised ; the margin of the body-whorl flat- tened, and serrated with flat spines ; inner lip united to the outer ; pillar and aperture as in the last. C. imperialis. Mart. 173. f. 1714. * Is this the Turbo iugvbris ? Zool. Journ. v. 345. t Except in the first genus, which connects this sub-family and the SenectirHE, and in T. Niloticus (as it is said), which connects Canthorbit with Trochtts, $ Connected to Cidari» by C. rugotus. 350 SHELLS AND SHELL-FISH. PART II. Pyramided Sw. Imperforate ; spire much elevated, pyramidical, acute ; basal whorl beneath much flat- tened, and scarcely convex ; pillar spiral, the base very short, turning inwards, and then outwards, but smooth ; outer lip thin; inner wanting.* (fig. 109- c.) obalisca. Mart. 160. f. Nilotica. Mart. 168. f. 1614. 1511, 1512. virgata. Ib. 160. f. 1514. foveolata Gm. Mart. 161. f. marmorata. Ib. 167. f. 1606. 1516, 1517. Mauritiana. Ib. 163. f. 1547. Lamprostoma Sw. Umbilicated ; pyramidical, spire elevated, acute ; basal whorl much flattened beneath, slightly convex ; pillar spiral j the base short, and marked by distinct plaits ; aperture striated ; inner lip wanting. L. maculata. Mart. 168. f. 1515, 1516. Carinidea Sw. Imperforate ; spire pyramidical, acute ; basal whorl concave beneath, and carinated round its circumference ; aperture oval, entire, slightly angu- lated at the base of the pillar, which turns inwards. C. concavus. Mart. 168. f. brevispinus. ? Sow. Gen. 1620, 1621. (Turbo.) f. 1. TBOCHUS Linn. Operculum horny ; shell trochiform ; the basal whorl broad ; aperture oval ; sometimes an- gulated by the union of the pillar and the outer lip, but rarely toothed or striated, f Chlorostoma Sw. Deeply umbilicated almost to the top of the spire ; inner lip forming a semi-margin to the umbilicus ; outer lip angulated at the base, with one or two tubercles ; body-whorl almost flat be- neath, and nearly carinated at its edge ; aperture remarkably oblique : representing Monilea.^. C. argyrostoma. Mart. 165. f. 1362, 1363. umbilicaris. Ib. 171. f. 1666. * Troch. Niloticus is probably esculent between this and Lamprostoma ,- but J have not seen a thoroughly full-grown specimen, with the mouth quite formed : the operculum is said to be horny ; but this may be doubted. t Except in Trochidon, which represents Monodonta Lam. in this circle. j Track, merula Lam. connects this sub-genus with Pagodella. PART II. TROCHINJ3. 351 Trochus Linn. Umbilicus either very open or small, but always apparent; base of the outer lip sinuated where it unites with the pillar ; inner lip generally spreading, flattened,, and concave ; body-whorl convex beneath, rounded on the sides ; aperture obliquely round ; spire short, depressed, pointed, (fig* 111.) T. pica. Mart. 176. f. 1750. cinerarius Linn. Mart. 171. magus. Ib. 171. f. 1656. ' f. 1686. Pagodella Sw. Trochiform ; generally thin, and always not perlaceous ; aperture and pillar perfectly united and entire ; operculum horny. P. major. Mart. 163. f. 1541, 1542. tectum-persica. Ib. f. 1543, 1544. Trochidon Sw. Trochiform ; spire more elevated than in the last; but the base of the pillar either angulated, umbilicus none, or forming a tooth more or less deve- loped, often with a lateral, depressed groove, but no umbilicus ; margin of the outer lip thin, the inside rarely striated, (fig. 109- d.) T. labeo. En. Meth. 447. viridis. Ib. 447. f 2. f. 1. canalifera. Ib. f. 5. Calliostoma Sw. Imperforate : spire elevated, acute ; aperture broader than high, transversely ovate, hardly sinuated at the base, and slightly oblique ; shells always smooth, and often polished: representing Cidaris. zizyphina. Pen. Zool. pi. 80. annulata. Ch. 165. f. 1551-2. f. 103. doliata. Ib. f. 1579 — 1583. conuloides. Lam. No. 47. granatina. Mart. 170. f. conula. Mart. 166. f. 1588. 1654, 1655. erythroleuca.Ib.l62.f.!529. Australis. Zool. Jour. v. 331. MONODONTA Lam. Base of the pillar forming a distinct tooth ; umbilicus deep*, with a deep groove below ; aperture striated ; outer lip not thin at the margin. Elenchus Humph. Shell smooth ; spire considerably * Except in Elenchus and Echinidea. 352 'SHELLS AND SHELL-FISH. PART n. lengthened; body -whorl comparatively smaller; base of the pillar with a slight angle, or an obsolete tooth ; aperture smooth, very brilliant; passing into Calli- ostomus. E. Iris. Mart. 161. £ 1652, splendidulus. Sw. Sp. Nov.* 1653. (fig. 109. a.) Echinella Sw. Shell imperforate, granulated, not per- laceous ; spire considerably lengthened; pyramidical ; base of the pillar with a distinct tooth ; aperture striated : representing Pagodella. E. granulata. Sw. Sp. Nov. coronaria. En.Meth.447.f.6. Monodonta Lam. Turbinated ; in general umbilicated, having a groove below, and a tooth at the base of the pillar ; aperture nearly round, striated within ; um- bilicus never toothed : representing Senecus and Tro- chidon. M. retusa. En. Meth. 447. f. 4. Fragella Sw. Trochiform ; umbilicus deep, always open, and toothed round its margin ; base of the pillar twisted, and forming a tooth -like process at its tip : representing Trochidon. Pharaonis. En. M. 447. f. 7. Sowerbyana. Sw. Sow. Gen. undata. Ib. 447. f. 3. f. 9. 11. (Trochus.) Monilea Sw. Umbilicus deep and wide, but the edges quite smooth, with a thickened half margin, formed by the inner lip, which terminates abruptly ; base of the outer lip with one or two tubercles, or obsolete teeth ; margin of the whorls concave ; inner lip often striated : representing Chlorostoma. M. callifera? Lam. Sys. 27. No. 59. SOLARIUM Lam. Shell nearly ^discoid, not perlaceous ; spire none ; aperture angulated, smooth within ; the edge acute ; the lips wanting, (fig. 109- i, k.) S. perspectivum. En. Meth. 446. f. 1 . ONUSTUS Humph. Shell trochiform ; the surface irre- gular, and often covered with extraneous bodies * Small, entirely fawn colour, or light brown ; aperture of the most brilliant purple and emerald green. Australia. PART II. ROTELLIN-ffi. 353 cemented and incorporated with the calcareous sub- stance of the shell ; the under part of the body-whorl flattened or concave, umbilicate. O. Solaris. Mart. 173. f. 1700, 1701. Indicus. Ib. 172. f. 1697, 1698. SUB-FAM. ROTELLINJE. Substance perlaceous ; shell depressed, smooth, and highly polished ; mouth thin ; umbilicus closed.* CHRYSOSTOMA/S'W. Shell turbinate; the whorls few and convex; aperture effuse, round ; inner lip thickened, just over and almost concealing the umbilicus. Nicobaricus. Mart. 182. f. 1822-1825. (fig, 109.) ROTELLA Lam. Shell flattened, nearly discoid, polished ; inner lip very thick, and spreading over half of the under surface ; aperture small, angulated j operculum horny, (fig. 109- f, 9-) R. lineotata Lam. Mart. 166. f. 1601. e,f, g. THELIDOMUS Sw. (fig. 113.) Turbi- nate, sub-trochiform ; umbilicus large,, open ; the whole shell entirely com- posed of grains of sand. Braziliensis Sw. (Jiff. 113.) SUB-FAM. PLEUROTOMARLE. Trochiform ; the aperture with a slit or fissure. Fossil only. PLEUROTOMARIA Defrance. Spire more or less elevated. Being only found in an imperfect or fossil state, nothing has been determined as to the umbilicus,, substance! operculum, &c. P. reticulata. Sow. Gen. t. 1. * These have probably no operculum, and Rotella may be an internal shell. 354 SHELLS AND SHELL-FISH. PART II. SUB-FAM. PHASIANELLIN^E. Obovate, spiral, polished; aperture oval; spire longer than, or equal to, the aperture ; operculum shelly. PHASIANELLA Lam. Umbilicus none. (fig. 109. &•) P. buliraoides. En. Meth. 449. f. 1. FAMILY HALIOTID.3E. The Ear-Shells. Shell disk-shaped entire ; the spire nearly obsolete, de- pressed, convolute, mostly lateral, and of only two or three minute whorls ; pillar none ; operculum none. HALIOTIS Linn. Iridescent ; ear-shaped ; a row of per- forated holes on the thickest side of the aperture. The sub-genera remain to be determined. STOMATIA Lam. Oval or oblong ; the shell resembling Haliotis, but without perforations. The types of form are enumerated at page 232. CALYPTB^A Lam. Shell not perlaceous ; patelliform, but with the first rudiments of an internal support, and often of a spire. Bicatittus Sw. Shell patelliform ; spire or whorls none ; a cup- shaped appendage within, more or less complete B. extinctorium Sw. Sow. Gen, f. 3. deformis. Ib. f. 1. Calyptrtsa Lam. Patelliform ; internal appendage half funnel-shaped, but open in front. C. equestris Lam. Sow. Man. f. 234. Sow. Gen. f. 2. Haliotidea Sw. Spire prominent, formed of two whorls, and placed laterally ; umbilicus open, sigaretoides. * Sw. dilatata ? Sow. Gen. f. 9. ( Calyptraa. ) * This sub-genus seems to form, with certain Vetulince, the passage to our Chelinotus, or the Sigareti of authors. PART II. CHELINOTUS. SCUTIBBANCHIA. 355 Trochilla Sw. Shell conical, patelliform ; spire central, of two or more whorls ; umbilicus closed. T. auriculata. Sow. Man. f. 236. pileus. Ib. f. 237, 238. Biconia Sw. Patelliform., conical ; internal appendage forming a funnel-shaped fold, not open in front; apex central, sometimes with the vestige of a whorl. Humph. Conch, f. 11. and 12. CHELINOTUS Sw. Animal cheloniform, broad; de- pressed; the mantle much larger than the shell, lobed in front ; tentacula two, short, obtuse ; eyes basal ; mouth circular ; shell ear-shaped, thin, fragile, imperforate ; pillar none. Velutina Lam. Animal — ? fragile ; shell with the two spiral whorls raised, so as to resemble a Lymnia; no pillar ; epidermis thin, horny. laevigata. Sow. Man. f. 337. Chelinotus Sw. Shell thin, diaphanous, white, entirely concealed in the back of the animal, which is marked with hexagonal partitions. Sigaret de Tonga, Quoy, Voy. d' Astrolabe. Coriocella Blainville. Animal broad oval, with the anterior lobes not prolonged, or the back divided as in the last ; shell thin, flexible, membranaceous.* C. niger De BlainviUe. Man. de Malac. pi. 42. f. 1. CREPIDULA Lam. Shell boat-shaped; the apex or spire at the narrowest extremity : half of the internal cavity covered by a testaceous plate. C. fornicata. Sow. Gen. f. 1. aculata, Ib. f. 5. TRIBE 3. SCUTIBRANCHIA. The Limpets. Shell patelliform or cup-shaped ; without any spire or internal support. FISSURELLA Lamarck. An oval aperture at the apex; or highest part of the shell. * Griff. Cuv. xii. 68. A A 2 556 SHELLS AND SHELL-FISH. PART II. Fissurella. Apex nearly central ; aperture large, oval simple. F. picta. Sow. Gen. f. 1. gigas. Sw. Sp. Nov. Machrochisma Sw. Aperture very large, oblong, placed closed to the margin. M. hiatula Sw. Sow. Gen. f. 5. Clypidella Sw. One extremity of the shell, near the perforation, slightly raised, truncated, and sub-emar- ginate. C. pustula. Sow. Gen. f. 3. Fissuridea Sw. Sub-conical, cap-shaped ; the summit close to the posterior margin ; the perforation narrow. T. pileus. Sw. Sp. Nov. EMARGINULA Lam. Either patelliform or cap-shaped ; the apex near the posterior end ; the anterior margin or summit with a very narrow slit or fissure. Emarginula Lam. Cap-shaped; fissure on the an- terior margin. E. reticulata. Sow. Gen. fissura. Sow. Man. f. 241. £ 5. elegans. Ib. f. 4. Cemoria Leach. Cap-shaped ; fissure down the centre of the apex. C. Fleming!!. Sow. Man. f. 244. Rimula Def. Cap-shaped ; fissure long, in the middle of the shell ; margin entire. R. Blainvillii. Sow. Gen. f. 243. Parmophorus Lam. Patelliform ; fissure assuming the form of an anterior sinus, scarcely perceptible on the anterior margin. P. elongatus. Sow. Gen. f. 1. breviculus. Sow. Gen. f. 2. Hemitoma Sw. Patelliform ; the fissure not cut through the shell, but merely forming an internal groove. H. tricostata Sw. Sow. Gen. f. 6. HIPPONYX. Shell cap-shaped ; the apex sometimes PART II. CYCLOBRANCH1A. 35? produced and slightly curved inwards ; muscular im- pression semi-circular. Hipponyx De Fr. Cap-shaped or patelliform ; strong ; the margins thick,, and reposing upon a thin, flat- tened ; testaceous plate, forming a second valve, cornucopia. Sow. Man. f. 199. Pileopsis Lam. Shell cap-shaped; thin; the apex much produced and incurved ; no basal support or internal appendage. P. Hungaricus. Sow. Man. f. 240. PEDICULARIA Sw. Shell irregular, sub-patelliform ; a thick, large, obsolete apex on one of the longest sides, and an internal callous rim within, on one side only ; circumference undulated, irregular. P. Sicula Sw. (fig. 44.) PATELLA Linn. Shell entire, simple, cup-shaped or patelliform ; apex pointed, entire.* P. miniata. Sow. Gen. f. 2. Siphqnaria Sow. One side more dilated than the other, and marked by an internal groove. S. Sipho. Sow. Gen. f. 1. TRIBE 4. CYCLOBRANCHIA. The Chitons.* Animal patelliform, oval ; the mantle coriaceous ; the back covered with imbricate shelly plates ; no tentacula. CHITON Lin. Back with large transverse plate ; zone, or mantle, wide, covered with small scales, either imbricate or reticulate. C. squamosus. Sow. Gen. f. 2. CANTHAPLEURA Guild. Plates as in Chiton ; the * The fresh-water genus Ancylus has the same shaped shell, but the animal shows it belongs to the Lnnnniante. f Not haying analysed this tribe, I have adopted the genera and arrange- ment of Guilding, see Zoo/. Journ. xvii. p. 27., especially as they thus form a circular group. A A 3 358 SHELLS AND SHELL-FISH. PART II. mantle rough, with moveable spines, prickles, setace- ous hairs, or granules. C. spinosus. Sow. Gen. f. 1. PHAKELLOPLEURA Guild. Plates moderate ; the mantle ornamented with a single series of tufts of radiating hairs. P. fascicularis. Sow. Gen. f. 3. CHITONELLUS Lam. Body larvaeform ; plates small, detached ; mantle naked ; sides with punctures, re- sembling spiracles. C. larviformis Burrows, latus Guild. Z. J. xvii. p. 78. CRYPTOCONCHUS Blainv. Plates moderate, entirely co- vered with the soft down of the zone, each plate having two lateral and tabular pores, and four on the anterior plate. C. porosus Burrows. TRIBE 5. TECTIBRANCHIA. The Sea Slugs. Body naked ; branchia generally covered by a coriaceous or testaceous plate, or oviform shell, which is more or less concealed in the mantle, or its lobes ; eyes sessile, minute. SUB-FAM. 1. PHYLLIDIN.E. Shell none ; body shaped as in Chiton ; mantle coria- ceous ; branchia folliculated, placed on both sides of the body, under the edges of the mantle j tentacula small, short, two or four. PHYLLIDEA Cuv. Shape oval ; tentacula four, the upper pair cylindrical and pointed, the under very small, inferior, and placed on the side of a small mouth. P. pustulosa. Rlipp. Atlas, i. pi. 7. f. 1. DIPHYLLIDEA Cuv. Posterior end narrowed ; tentacula two, the inferior pair represented by two tubercles. D. Hneata Otto. PART II. APLYSIAN^E. 359 SUB-FAM. 2. APLYSIANI^S. Sea Hares. Mantle dilated, undulated at its edges and thrown on the back ; branchia dorsal, pectinated, generally covered with a convex, irregular, horny, or calcareous plate ; tentacula two or four, ear-shaped. APLYSIA Linn. Animal with a short neck ; tentacula four, the upper and large pair flat, and folded so as to resemble the ears of a hare ; mantle very large, and sufficiently dilated for swimming, fasciata. Rang. Ap. pi. 6, 7. Argus. Ru'pp. Atl. i. pi. 7. THALLEPUS Sw. Body more slender and fusiform ; the lobes of the mantle short, and incapable of being used for swimming ; tentacula two, large, ear-shaped ; eyes not visible. T. ornatus Sw. Sp. Nov. See page 250. DOLABELLA Lam. Body pyriform, very broad behind ; the lobes compactly folded on a hatched-shaped cal- careous shell, which covers the branchia. D. Rumphii Lam. Blainv. Man. pi. 43. f. 5. BURSATELLA Blainv. Body nearly globular ; the dor- sal edges of the mantle united together, but leaving a short opening for the passage of the water to the branchia, which have no covering. B. Leachii Blainv. Man. pi. 43. f. 6. NOTARCHUS Cuv. Body shaped much like that of Aply- sia, covered with flat palmated lobes or membranes; tentacula two, large and palmated; mantle and branchia as in Bursatella. N. laciniatus. Riipp. Atl. i. pi. 7. f. 2. SUB-FAM. 3. BULLING. The BuOas. Animal without apparent tentacula ; body oblong ; both extremities obtuse ; eyes vertical, very minute ; bran- chia dorsal, covered by a convolute shell, destitute of A A 4 360 SHELLS AND SHELL-FISH. PART II. any spire ; the base widest : this in the typical species, is covered by the lobes of the mantle; in others the whole animal is contained in the shell.* Lam. Shell internal, oval, colourless ; inner lip thin ; apex umbilicated ; animal oblong, without tentacula. aperta. Sow. Man. f. 248. ? Guildingii Sw. (See^. 46.) Sulla. Animal furnished with two connected bony plates ; shell obovate ; contracted above, and effuse at the base. B. Lignaria. Sow. Man,, f. 251. Vesica Sw. Animal unknown ? probably contained within the shell ; shell oval, solid ; apex umbi- licated ; aperture entire ; contracted above. ampulla. Sow. Man. f. 252. Naucum. Sow. Man. f. 250. Aplustra Schum. Animal - ? shell solid, but thin ; furnished with a distinct but depressed spire. A. fasciata. Sow. Man. f. 249. Bullinula Beck. General shape of the last ; but the spire is slightly produced and conic : a doubtful type ? B. lineata. Sow. Man. f. 253. Vitrella Sw. Animal - ? shell internal, hyaline, or sub-transparent ; convolute ; the apex carinated ; the substance elastic. V. fragilis. Sow. Man. f. 247. DOBIDIUM Mecken. Animal with the lobes dilated into fin-like processes, but without a shell. D. carnosa. Cuv. Mem. SUB-FAM. 4. GASTEROPTERID./E. GASTEBOPTERON Meek. Animal short, ovate, natatorial ; the margins of the foot dilated into broad wing-like * The arrangement of this sub-family, founded chiefly upon the shell, is purely artificial, no knowledge having been gained of the greater part of the animals. Such genera as Cryptella, &c., founded merely upon the branchial covering of some unknown animal, can never be admitted into Malacology. PART II. PLEUROBRANCHlNjE. 361 lobes ; shell none ; branchia naked, placed on the right side of the body. G. Meckelii. Blainv. Man. de Malacol. pi. 45. f. 3. SUB-FAM. 5. PLEUROBRANCHIN^. Animal cheloniform, branchia pectinated, placed on the right side under the edge of the mantle which sometimes covers a calcareous shell. Umbrella Lam. Animal large and circular ; anus tu- bular, placed behind the branchia ; tentacula two, short, as in the next genus ; with eyes at the in- ternal base, between which is a proboscis. Shell resembling a limpet ; but the middle is thickest, and the edges very sharp. U. Indica. Blainv. Man. pi. 44. f. 1. PLEUROBRANCHUS Cuv. Animal cheloniform ; body overlapped by the mantle and the foot; the. former sometimes contains a small oval plate, either horny or calcareous ; mouth small, probosciform ; ten- tacula two, tubular, and short, citrinus. RUpp. Atl. i. 5. f. 1. Forskalii. Ib. pi 5. f. 2. PLEUROBRANCH^/A Meckel. Anus above the bran- chia ; tentacula four, short, remote ; shell none ; branchia and genital orifices as in the last. Meckelii. Leve. Dissert. Griff. Cuv. xii. 43. ORDER DITHYRA. Bivalve Shells. TRIBE 1. TUBULIBRANCHIA Cuv. Animal inhabiting a tubular shell affixed to other sub- stances and somewhat spiral at its tip ; tail turned un- der the body and terminated by a thin operculum j head obtuse, with two short tentacula with sessile eyes ; mouth a vertical orifice with two filaments beneath be- longing to the foot ; hermaphrodite.* * The animal of Magilis being unknown, I am afraid of including it in this group. 362 SHELLS AND SHELL-FISH. PART II. VEBMETUS. Shell tubular, contorted; the terminal whorls spiral. G. lumbricalis. Sow. Man. f. 345. VEBMILLIA Lam. The terminal whorls not spiral. V. triquetra. Sow. Man. f. 7. SILIQUABIA Brug. Terminal whorls spiral ; a narrow punctured fissure on one side of the shell. S. anguina. Sow. Man. f. 1. TRIBE 2. MACROTRACHI^E. Animal with one or two long respiratory siphons, either distinct or united ; the margins often furnished with little teeth. FAMILY 1. PHOLID^. Shell bivalve, sedentary, generally perforating, opening at one or both ends ; the valves often prolonged into a shelly tube, sometimes of great length : representing the Tubulibranchia. ASPEBGILLIUM. Animal living in sand, and not fixed on or upon any other substance : inhabiting a calca- reous tube. Aspergillium Lam. Shell tubular, nearly straight, one PART II. PHOLID^i. 363 extremity open, at the other closed by a plate which is perforated with small holes, near to which are the bosses : lives in sandy shores, (fig. I J 4. /, g.) A. vaginiferum Lam. Sow. Gen. f. 1. 2. Clavagetta Lam. Two irregular valves placed within a short shelly tube, dilated at its open extremity, and to which one valve is fixed or soldered at the other : perforates stones, &c. (fig. 114. a, A,) C. aperta. Sow. Gen. f. 1 — 4. Fistulana Lam. Animal not perforating ; tube purse- shaped, straight, the narrow extremity open, the other closed; a transverse septum crosses the tube, and incloses at its largest end a bivalve shell, which is elongated, solen-shaped, gaping widely at the basal margin, and united by a ligament, (fig. 114. m.) F. clava. Sow. Gen. f.l— 4. GASTBOCHINA Lam. Animal perforating or parasitic ; tube calcareous, clavate, nearly divided longitudinally for half its length by an internal ridge, which forms a double aperture ; the other or thick extremity en- closes an ovate bivalve shell, gaping very wide ante- riorly ; hinge linear and marginal ; teeth none. (fig. 114. b, c,d.) G. modiolina. Sow. Gen. f. 1.* PHOLADOMYA Sow. Shell not tubular, pholas- shaped, perlaceous, slightly gaping, no ac- cessary valves; ligament short ; external hinge with a small elongated pit somewhat triangular, and a marginal plate on each valve ; umbones very close. P. Candida. Sow. Gen. Man. f. 57. (fig. 115.) PHOLAS Linn. Animal perforating but not tubular ; * I consider the perforating species to be types of a different sub-genus ; and probably those which are parasitic upon other shells should likewise be separated. 364 SHELLS AND SHELL-FISH. PART II. shell free, oblong-ovate,, thin, with an internal com- pressed tooth in each valve and accessary pieces. Pholas Linn. Shell gaping at both extremities over the umbones ; ligament none. [fig. 122./.) P. dactylus. Sow. Gen. f. 1. Pholidcea Leach. Resembling Pholas., but the anterior end is closed by a thin calcareous prolongation of each valve, and the posterior end has a cup-shaped ap- pendage. (fig.im.g.) T. papyracea. Sow. Gen. f. 3. Man. f. 56. Martesia Leach. General characters of Pholas, but both extremities are closed. M. clavata Auct. {fig. 122. t.) Xylophaga Sow. Habit of Pholas ; but the shell is orbicular, widely gaping anteriorly, and with ac- cessary valves ; each valve with an incurved tooth, and an internal transverse rib. dorsalis. Sow. Man. f. 50, 51. TEREDO Linn. Shell tubular, irregular ; the valves pholas- shaped, short and nearly orbicular. Teredo Linn. Valves resembling Xylophaga; placed at the thickest extremity of a long, irregular tube, " which is open at both ends, the anterior end di- vided into two apertures furnished with two oper- cula."* (fig. 114. M.) T. navalis. Sow. Gen. Man. f. 48, 49. Teredina. Tube clavate, irregular, nearly divided into two, by a projection on each side within, thus form- ing a double opening at the smallest extremity ; valves as in Teredo, but wholly external, incrustated with the tube, and having accessary valves. T. personata. Sow. Gen. Man. f. 46, 47. (fig. 114. «.) * I have not leisure to look into these characters, and have therefore adopted Mr. Sowerby's account of this and the next genus. PART II. M Y AD.E. SOLENIN.3:. 365 FAMILY 2. MYADJE. Gaping Bivalves. Shells regular, always with defined cardinal teeth ; valves more or less gaping at one or both extremities. 116 J SOLENINJE. Solens. Shells generally linear, and always open at both extre- mities ; cardinal teeth distinct. SOLEN Linn. Shell very straight, broad,, linear, and of equal length throughout ; umbones very small, ter- minal ; cardinal teeth small ; ligament long, exter- nal, truncatus. Sow. Gen. f. 1. vagina. Ib. f. 2. (Jig. 116. 6.) ENSATELLA Sw. Shell slightly curved. E. Europea Sw. (Solen Ensis Auct. ) NOVACULIXA Benson. Straight, of equal length throughout ; the extremities rounded ; umbones towards the middle ; cardinal teeth ^ ; dorsal margin slightly thickened. N. Gangetica. Sow. Man. f. 63. 366 SHELLS AND SHELL-FISH. PART II. LEPTON Turton. Small, nearly round ; umbones cen- tral ; teeth ? The cardiform type. L. squamosus. Sow. Man. f. 62. SOLENOCURTIS. Shell depressed, thin, transverse, oblong ovate ; the valves slightly gaping at one extremity ; cardinal teeth and umbones nearly central. Kolenella Sow. Oval, compressed ; epidermis glossy ; hinge margin nearly straight; cardinal teeth wanting ; posterior lateral teeth numerous, sharp ; anterior end somewhat truncated : representing Nucula. S. Norisii. Sow. Man. f. 138. Solenocurtis Blainv. Oblong-ovate, nearly linear; umbones small, nearly central, with a thickened in- ternal transverse ridge; ligamental margin much thickened. (fig. 11 6. e.) S. radiata. Sow. Man. f. 61. Blainv. Man. pi. 80. f. 1. Sanguinolaria Lam. Ovate, compressed ; posterior end sub -rostrated ; anterior rounded ; cardinal teeth small, f. (fig. 116. d.) S. rosea. Sow. Man. f. 98. Glauconome Gray.* Obovate, not gaping, sub-ventri- cose, and rounded anteriorly, narrowed and com- pressed posteriorly ; cardinal teeth 4, some of which are bifid ; ligament oblong ; external epidermis ex- tending over the margin ; fluviatile : apparently re- presenting Mactra in this genus, G. chinensis Gray. Sow. Man. f. 64. Solenymia Lam. Shape of Solenocurtis, but some- what cylindrical ; umbones very small, and placed laterally ; hinge margin straight ; valves gaping on their anterior end ; cardinal teeth -}, dilated and compressed, with a callous ridge between ; ligament * I have not seen this shell, which, from the figure quoted, has exactly the shape of Unto ovata. PART II. SOLENIN^. MY A. 36? internal and external: representing Pandora and Glycymeris. Epidermis thin, shining, dilated. S. Mediterranea. Sow. Gen. f. 112. (fig. 116. a.) MYA Linn. Shell thick, ventricose, ovate, transverse, one end truncated and gaping ; umbones generally nearly central and prominent; cardinal tooth gene- rally large ; spatulate valves often gaping. Anatina Lam. Hyaline, thin ; cardinal tooth spoon- shaped, sometimes with a transverse internal append- age, or plate, like an additional tooth, (fig. 11 6. f.) M. subrostrata. En. M<*th. 228. f. 3. Mya- Linn. Shell thick, strong ; cardinal tooth spatu- late ; both extremities gaping*; cardinal teeth J. M. truncata. En. Meth. 229. f. 2. (fig. 117. t,c.) Panopia Lam. Resembling Mya; cardinal teeth \, acute ; ligamental margin greatly thickened ; liga- ment external, (fig. 116. c.) P. Aldrovandi. Sow. Man. f. 65. Corbula. Inequivalve, ovate ; umbones central, one more prominent than the other ; valves not gaping ; cardinal teeth -J, bearing the ligament : leading to Mactra. (11?. e,/.) Sulcata. En. Meth. 230. f. 1. C. nucleus. Sow. Man. 89. * Connected to Anatina by Anatina rupicola Lam. 368 SHELLS AND SHELL-PISH. PART II. Pandora Lam. Inequivalve, thin, rostrated, perlaceous ; one valve flat, the other convex ; ligament internal ; umbones small; cardinal teeth ~ , lamellar, sagittate, or like aV reversed: connected to Anatina.^fig. 1 17. Voluta olla, Diadema &c. are strictly of this de- scription, as also those of Harpula fulgetrum, Sea- phella papillosa, and other volutes : but C. vespertilio is not so, for the spire is distinctly plaited, and even rough with obsolete spines. Measurement, see Length. Multlvalve. The only multivalve Testacea, properly so called, are the chitons and the perforating genera belonging or closely allied to Teredo and Pholas. The Cirripedes are annulose animals or insects, and have no place whatever among the molluscous tribes, any more than beetles or butterflies. Muscular Impressions: those indented marks in ace- phalous bivalves, indicating the insertion of those muscles by which the animal is attached to its shell. Of these there are three principal sorts, — lateral, central, and pallial. 1 . The lateral impressions indicate the animal to have two adductor muscles, as in Unio Cardium, and all the most typical bivalves. 2. A central impression shows vft the presence of but one adductor muscle, which is generally in the middle of the shell, as in the common oyster. All these shells, however, are furnished with the third or pal- lial muscle, which is indicated by a depressed line, often sinuated, running parallel with the ventral margin. Obsolete. This term, in conchology, is more properly restricted to implying a faint indication of par- ticular characters. Thus, very slight and partially 400 SHELLS AND SHELL-FISH. indistinct stria upon a shell are called obsolete 'stria, not because they are worn off by accident, but be- cause they are only rudimentary, or very slightly developed. Operculum. The hard lid, either corneous or cal- careous, which closes the mouth of many spiral shells, and is carried on the posterior part of the belly of the animal. It generally fits the aperture of the shell, but is sometimes smaller, in which case it is drawn inside until the animal adjusts it to the diminished circumference of the whorl. Nearly all the predaceous tribes have this protection ; but it is never found among such as envelop their shell in the lobes of their mantle. Ovate. Not oval, but egg-shaped ; one extremity being thicker and more obtuse than the other. Patelliform. Dish shaped, as. the limpets. Pectinated. Processes resembling in form and arrange- ment the teeth of a comb, as are the spines of some species of Murex. Perforated. As if bored or indented by an awl : the holes or perforations in the ear-shells are of this de- scription. Plicated. Applied to any part of a shell which has plaits or folds, either upon the pillar or the external surface: the concentric ridges so common in the genus Venus are also of this description. Posterior margin. This term is confined to acephalous bivalves, and is that side of the bosses which contains the ligament. Ramose. Spines upon shells which send out others in a lateral direction, are termed ramose or branched. Recurved. Turned backwards, in contra-distinction to incurved. The canal of some Strombi and Cerithium are remarkably recurved. The apex of all the patelli- EXPLANATION OF TERMS. 401 form shells, however, are not always incurved, the top bending downwards or being erect. Reflected. Turned or folded backwards, a/is the thick- ened outer lip of the common garden, and many other of the terrestrial, snails. Reverse Shells, are such as have the aperture opening on the left side when it is placed in front of the spec- tator. Sinuated, or waved. Any part whose margin has one or more undulations : this appearance is produced by a projecting lobe being followed by a notch or hollow more or less deep. The outer lip of Struthiolaria and several of the Strombi are sinuated, but the latter so much so as to form abrupt lobes and corresponding notches. Sessile. Destitute of any support or peduncle, as in the shell of the Anomia. Those of Terebratula, on the contrary, are elevated in some degree, on a peduncle^ and are termed pedunculated. Siphon. A sucker: a fleshy process, generally long, cylindrical, and hollow ; protruded by the carnivorous and testaceous animals from the base or channel of their shells. The same term is given to the slender shelly tube which connects the chambers of cephalo- pod shells, or the Nautili. Spire. Those volutions of a spiral shell which are above the lowest or body-whorl, collectively form the spire of the shell, whatever shape it may assume. The variations in the form of this part are numerous. In some it is excessively lengthened; in others it is not even raised above the body- whorl. In Planorbis the spire is sunk, while in Cyprcea it is so small as only to be seen when the shell is young, after which it is covered over by the enlargement of the body- whorl or principal volution. Squamose. Having the appearance of scales. D D 402 SHELLS AND SHELL-FISH. Striated. Marked with lines, either elevated or raised., at parallel and nearly equal distances. Such marks are termed striae only when they are very slender., not much exceeding the breadth of a hair, or at most of the human nail : when they are deeper and in- dented, they are termed grooves; or, if elevated, ridges. Sometimes the striae are formed by a series of punctures, as in Mitra cardinalis, &c. ; while in other instances they are elevated and granulated, as Mitra granulosa. In bivalve shells they are almost always concentric, or following parallel to the outer margin. All these variations have been found of great importance in the determination of species, and hence require the closest attention. Sub. Nearly or partially, as sub-striate, sub-fusi- form, &c. Subulate. Awl-shaped, long, slender, and acutely pointed, as Terebra, Turritella, &c. Sulcated. Broad grooves, sunk beneath the surround- ing surface. Suture. A term applied to the line of junction in the whorls of spiral shells, or that where two parts join or fit into each other. Symmetrical. Where the two sides of a shell are alike. Terebrating Testacea are such as take up their habi- tations in other substances, as Pholas, &c. Tessellated. Divided into squares or chequers, either by a division of the colours, or by the crossing of the striae. Transverse. A line drawn across the breadth of a shell. Thus the coronations of the Volutes are transverse, so also are the bands on the Achatinte, and all those upon bivalve shells which radiate from the bosses. Trigonal or triangular. Having three equal or unequal sides, as Donax, Hyria, Cardissa, &c. Trilobate. Divided into three obtuse divisions or lobes. EXPLANATION OF TERMS. 403 Tricuspidate. When these divisions end in points. Truncated. Ending abruptly, as if cut off, as in the extremities of the typical Soleus, My a truncata, &c. The same term may be applied to the termination of the spire in several land-shells, which seem as if they had been broken off. Tubivalves. Such bivalves, like Teredo } as are pro- vided also with a tube. Turbinated. Turban or top-shaped ; the whorls con- vex, and generally but very little raised. The garden snails are good examples, but not the Trochi, their form being pyramidical. Umbilicus. A hollow opening, more or less wide, on the side of the inner lip of spiral shells : in some, as Scalaria and Sollarium, it is so deep as to ex- tend to the apex of the shell ; in others, as Tro- chus, it is small ; in Bulimus it becomes nearly obsolete ; and in Natica it is often entirely con- cealed by the spreading of the inner lip. In all these variations, however, the umbilicus is caused by the inner edges of the whorls not touching each other. Instances occur in certain laud-shells which are deeply umbilicated when young, but not at all when old. Undulated. Waved j nearly synonymous with sinuated, but more particularly applied to the colouring of shells. Scapella undulata and many other volutes are marked in this way. Valves. The two ordinary or principal pieces which comprise the covering of acephalous Testacea, or bivalves. Farias. Those strong elevated ridges which cross the whorls of several of the predaceous genera, as Murex, Triton, &c. : they mark the progressive enlargement of the shell, being the remnants of former apertures, beyond which the animal, when D D 2 404- SHELLS AND SHELL-PISH. grown, forms another aperture. Sometimes, as in Murex, these varices are irregular, and are either spined or foliated ; but in the harp-shells they are smooth and at equal distances. In Ranetta they are united, so as to form two lateral ridges ; while in Triton they are detached and remote from each other. In Cassis they are also alternate ; and, in the aberrant species, none whatever are perceived. Volution. Synonymous with whorl. Whorl. Each complete turn of the spire in a spiral shell is termed a whorl: the last, which terminates with the aperture, is the body or basal whorl ; the rest are the spiral whorls. APPENDIX. The following note on the extraordinary genus Herpa, from the Guilding MSS., and referred to in the text, is too valu- able to be omitted. HERPA Guilding. Animal terrestre, pulmoniferum. Corpus molle, subgelati- nosum, raucrone obductum, elongatum, contractile, depressum, antice praesertim attenuatum. Os apicale, minutissimum, obscurum. Fades contracta, emarginata. Tentacula nulla. Scutum nullum. Oculi cervicales. Solea magnitudine corporis, nee distincta. Glanduke plurimae ventrales mucorem ab ore transverso efiuadentes, unica majore central!, equa viscus lo- batum, molle, plicatile, parvulum, rare protruditur. Genus valde distinctum, et inusitatae formaa. Corpore fere toto erecto Herpa more serpentum prolabitur, viam mucore superillinens, et tentaculis carens cervice longo valde attenuate vestigia diriget. Genus Planariis facie quam plurimum analo- gum, ut Limacibus respirationis modo, locis, moribusque omnino affine. In the 8th number of the Zool. Journ. p. 443. a short notice of this genus was given, drawn from a single specimen which must now be struck out. The capture of many of them has enabled me materially to improve the description. They are very singular animals, and in their external characters have a remarkable resemblance to the Planarice, which, however, as Cuvier observes, inhabit only salt or fresh water, and therefore can have no relation of affinity with Herpa. Probably, the PL terrestris and Candida of Gmelin may resemble them in their economy. I have found the Herpes on the decayed fronds of D D 3 406 APPENDIX. palms, on the summits of high mountains, and on the dry lands within a few yards of the sea ; these always seeking cool places for concealment during the day, but never approaching the water, which upon being thrown into, they instantly quit." The largest of the three species discovered by our author, was Her- pa gigas, black above, dirty and paler beneath. It was from six to seven inches long, and was found creeping across a damp forest path ; but from the strange power it possesses of contrac- ting its body, it escaped through a small crevice of the box it was deposited in, before it could be more accurately examined. INDEX. *»* The page references are to the Author's remarks : to avoid a multiplicity of figures, the reader is referred to the occasional tables for the classifica- tion of genera. A. ACARDO. 373. Acephala, the naked, 5. n. The bi- valve Testacea, 25. Achatinae, snails with elongated spiral shells, 162. 174. 179. 334. Sub-typical, 170. 335, 336. A. marginata, 170. Sub-genera and analogies, 173. 175. 179. 336. Point of union with the Bulimi- nse, 183. AchatinellEe, 172. 338. Acrita, their nervous system gra- nular, 4. n. Probably consists of polypes, corals, and plant-like animals, 5. The group seems to to be ill-defined by naturalists, 43. Adanson, on the shell-fish of Sene- gal, 14. Adhesion, power of, often by in- numerable suckers, 30, 31. Of the Patella to rocks, 244. -Slglia, genus, 265. 378. Represents Hyria, 275. Affinity, theory of, 5. 7. 94. 189. 291. Of Testacea, form a conti- nuous circle, 41. et passim. Akera, 249. Ala?, 183. Alasmodon, 263, 264. 273. 381. A. undulatus and calceolus, 263. 288, 289. A. rugosus, 273. Alasmodontinae, the, 276. 287. 381. Connection with Anodons, 288. Analogies of the genera, 290. Amphibia, allusions to, 50. Amphidesma, 371. Amphiuma, worm-like salaman- ders, 43. Ampullaria, genus, 55. 339. Siphon of, 160. D D Ampullarinae, or apple-snails, 195. 339. Guilding's drawing of, 197. Analogies, in Malacology, different from affinities, 42. 189. 291. Con- sist of mutual representations, 49. Of Annelides with Nudibranchia, 51. Of Parenchyrnata with annu- lose Vermes, 52. Of zoophagous and phytophagous Gasteropoda, 111. See various classes and ge- nera. Analogy, a verification subordinate to that by affinity, 94. Anastoma, sub- genus, 192. 329. Ancillaria, aberrant group, 97, 98. 132. 323. Resemblance to Con- cholepas and Monoceros, 100. Ancillarinae, sub-family, 101. 133. 322. Anculosa, fluviatile, 199. 210. 340. Ancylus, freshwater limpets, 188. 338. Animal kingdom, links of compa- rison and resemblance betwixt various classes of the, 5. 7. 40. 42. Animalcule, classification of, 45. Annelides, ring-jointed, and hav- ing red blood, 7. Resemblances of, to fishes, 7. ; and to Testacea, 27. 51. Analogy with Nudibran- chia, 51. Annulosa, the, or insect tribes, 5. 4. Circle or group of, 38. 51. Ana- logies of, £2. Anodon, genus, 263. 287. Small depressed summit of, 273. A. ana- tinus, 286. Various other spe- cies of, 286, 287. Anodontinse, the, 259. 286. 381. Analogies of, 287. Anomia, 47- 389. Aphorrais, 138. 141. 157. 309. It« 4 40o INDEX. resemblance to Cerithium, 142. ; to Hostel laria,! 142. ; to Pterocera, 142. Aplustra, 360. A. pulchella, 249. Aplysia, sea hares, 25. 30. 238. 248. Typical characters of, 250. 359. Aplysianas, sub-family, 359. Aptera, a sub-typical class, 51. 53. Area, genus, 383. Arc-Ida;, or arch-shells, 260. 382. Argonauta, 48. Aristotle, the acknowledged leader of zoological science, 13. Arrangement, natural, 295. Aspergillium, the animal lives in sand, 362. Atrachia, tribe of, 255, 256. 377. Circle of, perfected, 258. Analo- gies of, 258. Auricula, 171. 209. 337- Genuine, 176. 178. Sub-genus, 180. Spe- cies of, 180. Aves, circle of, perfectly developed, 41. Certain analogies with typi- cal Gasteropoda, &c., 49. Avicula, description of, 257. 386. Aviculidee, the, 257. Muscles and pearl oysters, 383. Azeca, sub-genus, 183. B. Balia, 182, 334. Barnacles, classification of, 25. 28. Their analogy with cuttlefish, 52. Belemnites, fossil, 48. Bibliography of the testaceous Mollusca, notice of the, 13, et sea. Bicatillus, 354. Biconia, 355. Birostra, form of, 325. Bivalves, Aristotle's designations of the molluscous, 13. 21. Ace- phala, 25. Double shells, as the oyster and cockle, 27. All aquatic, 33. Sub-typical, 35. Devoid of eyes and tentacula, 36. Some analogy of, with Aves, 50. Order of Dithyra, 254. 361. Flu- viatile, 259. Blainville, M. de, system of, 17. His nomenclature objectionable, 13. 17. Brachidontes, 383. Brachytoma, new genus, 154. 314. Branch iopoda, of Cuvier, 23. 47. Anomian shells, 25. 47. 256. Buccinina?, or whelks, 63. 71. Base abrupt and notched, 73. 97. 301. Buccinum, genus, 62. 96. 302. B. Achatinum, 74. B. lasvigatum, 74. B. plumbeum, 82. B. strom- bioides, 123. Buliraus, description of, 170. 176. 335. B. proper, 177. Sub-genus, 178. Analogies of its sectional types, 179. Bulimi, conical spire of the, 163. 177. Sub-genera of, 178. Circle of, 181. Bulimulus undulatus, antiquensis, and proteus, 177. 335. Bulla, conformation of, 25. 55. 360. Connected with the Cyprzeidae, 59. 238. B. naucum, 249. B. aperta, 252. Bulling, sub-family of, 248. 251. 359. Bullinula, of Beck, 360. Bursatella, structure of, 251. 359. C. Calceola, 382. C. truncata, 289. Calliostoma, sub-genus, 218, 219. 351. Callithea, conformation of, 320. Calliscapha, 380. Calyptrea, 230, 231. 354. Natural station of, 233. C. chinensis, 234. Cancellaria, small incurved chan- nel of, 79.305. Cancilla, described, 320. Canthapleura, 357. Canthella, 202. Canthidomus, 342. Canthorbis, diversified sub-genera, 216. 349. Sub-genera and ana- logies of, 224 Canthyria, 276. 378. Capsa, 373. Capulis, 244. Caracolla, 328. Cardissa, 257. 259. 373. Cardita, 375. Cardium, 373. Carinea, 326. Carinaria, 48. Carinidea, sub-genus, 216. 350. Carrier shells, 212. 217. 228. Cassida?, analogies of, 89. 100. Cassidaria, of Lamarck, 69. 71. 299. Cassidea, 66. Form, and species of, 299. Cassinas, or helmet-shells, 63. 65. 297. Separate circle of affinity, 66. 95. Analogies to the Gaste- ropoda, 66. Cassis, genus, 65. 68. 71. Species of, 298. Castalia, of Lamarck, 284. 379. C. cordata, 284. Cemaria, of Leach, 243. 356. Cephalopoda, provided with a back- bone, form an order connected alike with the Vertebrata and Mollusca, 5, et seq. Perfection of sight of, 8. Lamarck's table INDEX. 409 of, 24. Cuvier's classification of, £5. Swimming, and fins of, 31. Search for its prey, 34. High organisation of, 38. Vestiges of testaceous, 40. Affinities of, 48. Extinct or fossil genera of, 48. Their analogy with fishes, 51 ; " and with barnacles, 52. Ceratodes, sub-genus, 197. 339. Ceriphrasia, sub-genus, 204. Ano- malous, 205. 342. Cerithidea, 198. 203. 342. Cerithinaa, or club-shells, 137. 139. 156. Characters of, 315. Cerithium, affinities of, 47. 136. 142. 205. Typical genus, 157. 315. Chama, how cemented or affixed to rocks, &c., 32. 47. 374. Chamids, the, 257. 374. Chelidomus, analogies of, 192. Chelinotus, group of, 234. 355. Chelosomae, 36. Organisation of, 45.238. 255,256. Chiton, of Linnaeus, 357. Chitonellus, 246. 358. Chitones, or Cyclobranchia, 25. 55. 238, 360. Their organisation, 45. Boat-shaped shells of, 58. Struc- ture of, 246. Chlorostoma, formation of, 218. 350. Chrysodomus, characters of, 90. 308. Chrysostoma, description of, 353. Cidaris, characters of the genus, 215. 349. Circle connecting Testacea, theory of a, 40. 95. Circle of existing birds, 41. Of extant and of ex- tinct Reptilia, 41. Of the entire class of Testacea, traced, 46. 48. Of the entire Animal Kingdom, 49. Cirripeda, articulated limbs of the, 6. First group of Annulosa, 6. Barnacles, 25. 28. Relationship between Cephalopoda and, 52. Clausilia, genus, 161. Characters of, 182. 334. Analogies of, 184. 209. Clavagella, 363. Clavalithes, fossils of the Turbi- nellaj, 77. 94. Characters of, 304. Clavatula, of Lamarck, 137. 155. 314. Clavicantha, 155. 314. C. echinata and auriculifera, fluviatile, 155. Cleidothasrus, 374. Clithon, 347. Clypidella, 356. Cochlicopa, 171. 173. 335. Cockle, the, 27. What called its foot, 30. Coecilia, 44. Columbella, J35. 313. C. merca- toria, 150. C. nitida, 151. Columbellinae, 61. 134. Conform- ation of the dove-shells, 1S7. 150. The typical, 143. 312. Operculum of, 150. The genera of, 152. Ana- logies of, 153. Complanaria gigas, 288, 290. 382. C. rugosa, 288. Conchifera, of Lamarck, 22. Concholepas, 73. 100. 301. Conchology, definition of, 10. The interests of geology require that shells should be scientifically stu- died, 12. Advantage of a genuine classical nomenclature, 13. In- feriority of modern compound names, 13. The Linnaean no- menclature, 14. System of Lin- naeus, 15, 16. Plates by D'Ar- genville and others, 14. Merits of the chief modern writers on, 15, 16. et passim. Great difficulty of completing a general and illu- minated work on, 18. Theory of a perfect circular group of all the Testacea, 40. 46. Knowledge of the animals increased, 97. Mr. Cuming's discoveries, 127. Theory of variation, 127- Sys- tematic arrangement of, 127. 295. Glossary, 391. Conella, 312. Cones, smooth shells of the, 61. 116. 311. With coronated tubercles, 116. The Coninffi described, 137. 310. Their genera, 150. 311. Their connection with the Strom- binae, 146. Analogies and cha- racters of the sub-genera of, 148. 150. Conidea, characters of, 151. 153. 313. Conilithes antedituvianus, 311. Conrehelix, remarks on, 127. 129. 321. Cortcelix, characters of, 321. Conorbis dormiter, 312. Con us amadis, 143. C. bandanus, 147. C. arenatus, 147. Types of the sub-genera, 148. 311. C. dor- miter, fossil, 149. Coralliophaga,259. 376. Corals, growth of, 65. Corbis, Lam., 371 . Corbula, 367. Coriocella, 235. 355. Coronaxis, 147. 311. Types of the sub-genera of, 148. Costellaria, form of, 320. Cowries, 61. 63. 324. Analogy of Cypraecassis to, ^67. The Cyprae- inae, typical, 135. 324. Crabs, with bivalve shells, 52. Crassatella, 369. Crassina, Lam.t 372. Crassispira, characters of, 152. 313. Creator, works of the, perfect, 42. 410 INDEX, Crenatula, 385. Crepidula, 230, 231. Natural sta- tion of, 239. 355. Cryptoconchus, zone of, 247. 358. Cryptostoma, 235. Cuma sulcata, 87. 307. Cumingia, 370. Cunicula planeata, cuneata, and purpurata, 268. 378. Cuttlefish, description of the, 5. Eyes of the, 8. Mode of swim, ming, 31. Food of, 34. Organi- sation of, 38. Extinct tribe of. fossil, 48. Cuvier, baron, character of his Rtgne Animal with regard to the , Mollusca, 16. His Memoires on the Testacea, 20. System of, 25. 35. 54. 211. Definitions in Grif- fith's, 53. Cyclas, 257. 369. Cyclinae, sub-family, 369. Cyclobranchia, comprehend Patella and Chiton, 25. 55. United by Cuvier to Dithyra, 54. Con- struction of, 58. 246. 357. Cyclocantha, with a circle of spines, 215. 348. Cyclocotyles, external parasites, 46. Cyclonassa, genus, 69. 300. Cyclophora, 186. 336. Cyclops, a genus of crabs, 52. Cyclostoma, 56. 171. 198. 336. Its analogy to Pupa, 169. Mouth, characters of, 185. 207. Discoid form of, 227. Cyclotus, of Guilding, 186. 336. Cylindrella, description of, 135. 326. Cyllene, the genus characterised, 81. 305. Approximates to Pseud- oliva, 82. Cymbiola, muricated, 101. 105. 317. Sub-typical, 126. Types of this genus represent those of Voluta, 117. Table of analogies, 118. C. vespertilio, 106. 318. C. tubercu- lata, 118. C. Braziliensis, 118. Cymbium, 104. 117. Cypraea, of Linnaeus, 61. 100. 324. Cypraacassis, 65. Analogy to cow- ries, 67. ; and to the Nassinae, 70. Characters of, 298. Cyprandae, affinities of, 59. 61. Shell described, 63. Analogies to be traced from the animals only, 115. n. 135. Family of, 324. Cypraeinae, typical forms, 135. 324. Cypraalla, structure of, 325. Cypraeova, 325. Cypricardia, 257. Cyrena, 370. Cytherea, 372. D. Decadopecten, 388. Delphinula, 215. 348. Diagram of the affinities of Muri- cidaa and Turbinellida?, 95. Dianchora, 388. Diceras, 375. Dipsas, of Leach, 263. 288. Discodoma, its circumference cari- nated, li)<2. 329. Dithyra, the Aristotelian term for bivalves, 13. Considered ana- tomically, 29. No apparent head or eyes in, 33. All bivalves are marine or fluviatile, 33. Food of, 33. Sub-typical, 35, 36. Circle of, 45. Analogies of, 49. 256. Survey of the order, 254. Gene- ralisation, 290. Arrangement of the order, 361. Dolabella, 251. 359. Dolium, 66. 299. Donax, 259. 373. Doridium, 252. 360. Doris, 24, 25. 37. 250. Has naked branchia, 54. Dove shells, 137. E. Ear-shells, see Haliotis. Earth-worms, their body disposed in rings, 7. Resemblances of, to the eel, 7. Eburna, types of, 81, 82. structure, 306. Eburnina?, base truncated and notched, 76. Sub-family of, 81. Genera and analogies of, 83. Af- finities of, 95, 96. Definition of, 305. Echinella, sub-genus of Trochug, 207.221.352. Echinidae, shells of the, 7. Ten- tacula [of, 7. Slow locomotion of, 7. Echinorynchus, 46. Echinus, the, its conformation, 7. Elenchus, 219, 220. 351. Emarginula, 58. 240. Characters of, 243, 244. 356. Enomphalus, fossil, 196. Ensatella, 365. Epistyla conica, 165. 331. Erato, 135. 326. Unites the Cyprse- idaa and Volutida?, 326. n. Eruca, SMI., 334. Erycina, 259. The name pre-occu- pied, 370. Eryx, instead of Erycina, 371. Etheria, 257. 390. Etheridse, family of, 390. Remark- . able affinities of this group, 257. INDEX. 411 Eulima, 343. Eyes, of the Testacea, 8. 33. 97. Of the Cephalopoda, 8. - F. Fasciolse, 37. Cup- shaped "suckers of the, 38. Food of, 46. ' Fasciolaria, 76. 94. Characters, 303. Ferussac, baron de, his work on the terrestrial Mollusca, 18. 171. n. Ficula, characters of, 85. 307. F. caudata, 85. F. rapa, 85. Firula, 46. Fishes, the Cephalopoda, among the Mollusca, bear greatest resem- blance to, 51. Fissurella, 58. 62. 240. Description of, 243. 355, 356. Fistulana, 363. Foot or belly of molluscous animals, 30.154. Foraminata, cephalopodous, 43. Foraminifera, investigated by the microscope. 44. Organisation of, 45. Fossils, arguments founded on those of testaceous genera now extinct, 40. Those of the larger reptiles, 41 . Of Cephalopoda, 48. Of Turbinellina», 77. Of Cones, 149. Snails, 196. Fragella/Sw., 352. Freshwater and fluviatile Testacea, 33. Fusinae, or spindle-shells, 76. 87. 90. 154. Delicate and elegant, 89. Analogies of Pyrulina2;to, 92. ; of Turbellinas to, 93. Sub-genera of, 308. Fusus, the typical genus, 87. 90. 308. Fossil, 77. F. bulbiformis, 90. F. ficulneus, colossus, coro- natus,91. F. colus, 96. Affinities ; of this group, 154. F. strombi- formis, typical, 154. F. Syracu- sensis, 154. G. : Galeomma, 257. 376. Gasteropoda, of Lamarck, 24. Of Cuvier, 25. Anatomy of the, 29. Progression of, 30. Eyes and head of, 33. Phytophagous, 33. The spiral univalves eminently typical, 34. 47. Developement of the perfect spire, gradual, 47. Analogies with the rest of the animal kingdom, 49. Primary divisions, 53. Analogies of the Muricinae and Turbinellidae, 53. Of Gasteropoda and Testacea, 60. Of the zoophagous and phyto- phagous classes, 111. 160. 195. 228. Aberrant tribes of, 239. Analogies of phytophagous and carnivorous, 242. Gasteropteron, 248. 252.362. Gastrochina, 257. 363. Generation of Mollusks, 29. 292. Generalisation, remarks on, 290. Geographic distribution of Tes- tacea, 34. Geology, its relations with con- chology, 9. 12. Fossils of the Paris basin, 77. Of Hordwell Cliff, 77. Geomitra, Terrestrial, 166. 332. Geotrochus, conical spire of, 163. 331, 332. Sub-genera of, 166. Geovula, group of, 208. 344. Gervillia, 385. Gibberula, Sto., 323. Glabella, 133. 324. Glauconome, 366. Globularia, 345. Glycimeris, 369. Gnathodon, 370. Gonidomus, 166. 332. Gonospira, 168. 333. Goniostoma, 177. 181. 335. Gryphzea, 389. Guilding, Rev. Lansdown, on the Mollusca of the Caribbean Seas, 17. 182. Drawings by, 18. n. 180. Discovery of Herpa by, 45. Draw- ing of a species of Nassa, 69. H. ' Haliotida?, the, 111. 356, 354. Con- formation of, 159. 228. Circular group of the, 231. Haliotidea, Sw., 354. Haliotis, or ear-shell, 25. 30. Cha- racters of, 111. 230. 354. The animal, 229. H. asinina, 231. Harpa, the harp-shells, 66. 298. Harpula, genus, 102. 134. 317. H. vexillum,71.106.119. H.hebraea, 106. H. fulminata, 107, 108. 119. 125. H. bullata, 107. 119. H. ly- riformis, 107. 119. H. costata, 119. H. nucleus, 119. H. poly- zonata, 119. H. musica, 119. H. sulcata, 119. H. Lapponica, 120. Mr. Broderip's Observations on H. dubia, 120. n. Sub-generic types, 120. 122. Analogies of, 120. 122. Harpula costata and multicostata, 119. 121. Haustellaria, 296. Hectocotyles, of Cuvier, 46. Helicellae, 164. 194. Their disk-like shells, 164. 333. Broad-lipped, 191. 412 INDEX. Helicida?, analogies of, 111. Land and freshwater snails, 158. Prin- ciples of investigating this tribe, 160. 291. The only division of Testacea breathing atmospheric air, 161. Circular group of, 161. Network of pulmonary vessels in, 161. Tentacula of, 161. Chief families described, 162. 186. Ana- logies of, 162. 227. Sub-families of, 162. Classification of, 326. Helicinas, or testaceous snails, 56. 162. 330. 336. Are typical, 163. Group extensive, 184. 194. Helicogena, of Ferussac, 191. Helisoma, 337. Helix proper, description, 164, 165. 227. 330. H. hortensis, 164. Ana- logies of, 166. Sub-genera of, 166. Hemicardium, 373 Hemicycla, 164. 193. Hemidonta, 288. 381. Hemifusus, 91. 94. Hemimactra, 369. Hemimitra, 199/342. Hemiodon, genus, 191. 330. Toothed aperture of, 164. 194. Hemisinus, 200. 341. Hemitoma, sub-genus, 244. 356. Hemitrochus, with elevated spire, 165. 331. Herpa, genus of soft Mollusca, dis- covered by Guilding, 18. 45. 161. 189.327. App.405. Heteropoda, divided into Cari- naria, Pterotrachia, and Phylli- roe, 25. By Cuvier, into Firoles and the Carinarije, 25. 48. Hiatula, 101. 132. 322. Hinnites, 388. Hipponyx, 31. 58. 240. 244. 357. Hippopus,<47. 257. 374. Horce Entomologies, notes on the Testacea in the, 19. Humphrey, George, F.L.S., system of conchology by, 15. His ar- rangement compared tabularly with Lamarck's, 20. Order I., Marine Testacea, 20. Order II., Fluviatile, 21. Order III., Ter- restrial, 21. His enumeration of univalves, 22. Hybrids, non -production of, 292. Hyria, its connection with Unio, 264. 285. 380. Hyria avicularis, 263. 278. H. cor- rugata, 263. 284. Hyridella, 380. Hyrina?, sub-family of, 282. 378. Analogies of, 285. lanthina, or oceanic snail, 31. 195. Inferobranchia, of Cuvier, 25. Infusoria, 4. Inoceramus, 385. Intestina, heterogeneous class of, Iridea, its affinity to Mysca, 283. Remarks on, 284. 379. Iridinina, 257. 262. 380. Prox- imate to Anodon, 264. Typical species of, 286. I. Nilotica, 286. I. elongata, 291. Iridinina;, sub-family, 286. 380. Isocardia, 374. Johnson, Dr., of Edinburgh, his valuable labours on the soft Mol- lusca, 43. n. K. Klein, 'his ornithological cabinet, 9. 11. Conchological labours of, 14. Lacuna, 241. Laevicardium, 373. Lamarck, his arrangement of the Testacea, 15, 16. 26. Compara* tive Tables, 20. First Order of Lamarck : Conchiflres dimyaires, 22.; tenuipedes, 22.; lamelli- pedes, 23. ; ambigus, 23. His se- cond order: Conchiferes mono, myaires, 23. : Branchiopoda, 23. His division of Mollusca into five orders, 23. ; Pteropoda, 23. ; Gasteropoda, 24. ; Trachelipodes, £4 ; Cephalopodes, 24. ; Hetero- poda, 25. Lamprodoma, 132. 225. 321. Lamproscapha, genus, 287. 381. Lamprostoma, 350. Lanistes, 384. Lanites, 339. Latiaxis, 82. 306. Ligumia recta, 291. Leiodomus, 69. 74. 302. Leiostoma, analogies of, 192. Cha- racters of, 308. 328. Leiostomus, 90. 94. Leptolimnea, 338. Leptoconus, 312. INDEX. 413 Lepton, of Turton, 366. Leptospira, 176.337. ,, Leucostoma, 173. 336. /8. Panopia, 367. Papyridea, 374. Parenchymata, affinities of the, 4. n. Intestinal Testacea, 35. ; and worms, 38. Parasitic Mol- lusca, 44. Cuvier's second fa- mily ; habits and food, 46. Ana- logy with annulose Vermes, 52. Parmophorus, 58. 62. 243. 356. Partula, of Ferussac, 179. n. Patella, or limpet, 25. 30. 47. 58. 357. Nearly stationary, 31. 234. 240. Adhesion to rocks, 244. Patularia, 287. 381. INDEX. 415 Pecten, 257. 259. 387, 388. Pectinibranchia, comprehend Tro. chus, Turbo, and many univalve marine Testacea, 25. 55. 185. Pectunculus, 383. Pedipes, 208. 344. Pedicular! a, 240. 245. 357. Pedum, 388. Periwinkle, 27 . Food of the, 33. Perna, 385. Persicola, 133. 323. ;a Petricola, 257. 376. Phakellopleura, 358. Phasianella, 207.213. 354. Pholadomya, 363. Pholas, its residence, 32. Power of enlarging their cave in rocks, &c., 32. 257. Of Linnams, 363. Pholidze, 257. 362. Pholidzea, 364. Phyllidea and Diphyllidea, 25. 58. 248. 250. 358. Phyllidinae, sub-family, 249. 358. Phyllonotus, 296. Physa, 187. 338. Phytophaga, Lamarck's subdivi- sions of, 24. Food of phyto- phagous gastropods, 33. 55. Or- ganisation of, 56. Sexes, 56. Re- spiration, 56. Confines of, with the Zoophaga, 59. Point of union with Zoophaga, 158. Primary divisions of the phytophagous shelUfish, 158. Families of, 160. Picidae, 262. Pileolus, 347. Pileopsis, 357. Pinna?, or wing-shells, 31. 387. Byssus, or silken tuft of, 32. Pirena, 156, 157. Pithohelix, 164, 165. Placuna, 389, 390. _ Placunomia, 390 Plagiostoma, 388. Planarite, the, possess no branchia, 28. Form of, 37. Analogy of naked slugs with, 45. Fossil, 196. Planaridae, true, swim freely, 46. Planaxis, 59. 198. 342. Animal of, 204. Planorbis, 55. 164. 186. 227. 337. P. corneus, 187. I Plant-like animals, 4. n. 5. Pleurobranchaena, 361. Pleurobranchinae, sub-family, 361. Pleurobranchus, 248. 252. 361. Pleuronectia, 388. Pleurotoma, 136. 154. 314. Pleurotomarias, 213. 223. 353. PleurotominEe, or slit-shells, 137. 152.314. Affinities of, 154. Cu- rious analogies of, 155, 156. Plicadomus, 332. Plicatella, 78. 304. Plicatula, 389. Poli, investigations of, 16. Polydontes, 329. Polygyra, 330. Polypes, or Arcita, 4. Polypes char- nues, 6. Tunicated, 6. Polytropa, 80. P. crispata, 81. Structure described, 305. Porcina, 104. Potadoma, 199. 200. 341. Potomida, genus, 137. 276. 281. 316. fc379. P. corrugata, 281, 282. P. elongata, 282. P. littoralis, 282. 289. P. Batava and Sicula, 282. Potomis, 156. 158. 315. Potomophila, 188. 338. Priapulis, 6. Processes for capturing prey, 34. Of the Nudibranchia, 37. Progression or locomotion of shell' fish, 30. 134. Psammobia, 259.370. Pseudoliva, 82. 306. Ps. plumbea, 133. Psittacidee, 262. Pterocera, typical of the Strom- binae, 138/310. P. lambis, 138. P. millipeda, 138. P. sinuata, 138. Analogy of the types of form of the genus, 144. P. latissimus, 144. Pteronotus, 296. Pteropoda, of Lamarck, 23. Of Cuvier, 25. No apparent head or eyes, 33. First tribe of Cepha- lopoda, 48. Ptilota, eminently typical, 51. Pulmonaria, 25. 55. 208. Pulvinites, 385. Puncticulis, 311. Pupa, inquiry intopupaceous shell*, 161. 163. Description of, 164. Cy- lindrical, maggot-shaped, 167. 183. 332. The sub-genera, 168. Ana- logy of Cyclostoma to, 169. ; of Clausilia with, 184. Pupella, 183. 334. Purpura, 63. 74. 204. P. lapillus, and imbricatus, 80. P. coronata, 301. Purpurinae, or purpuras, 63. 300. How far resembling Buccininae, 71. Analogies of Pyrulinae and, »73. Affinities, 95. 204. Pusia, 320. Pusiodon, Sw , 330. Pusiostoma, 150. 152. 220. 313. " Pustularia, 324. Pyramidea, 225. 350. Pyramidella, 343. Pyrella spirilla, 77. 304. Pyrena, 315. Pyrula of modern authors, 83. Iti shape, 84. P. perversa, 84. P. myristica, 86. P. hippocastanum, 86. P. lineata, 86. P. carnaria, 87. Characters of, 307. 416 INDEX. Pyrulinae, genera described, 73. 88. 307. Characteristics of the pear« ghells, 76. 83. Resemblances to Purpurinje, 88. j to Fusinas, 92. Q. Quadrupeds, analogical ' compari- sons of Gasteropoda>ith, 49. Quoy, M., new£shells discovered by, 11. 196. His researches in testa- ceous animals, 17. 156. 204. Leio- domus of, 69. His plates valuable, 128. R. Radiata, the second class of Mol- lusca, 5. Nerves of, radiated. 5. Destitute of eyes, 8. Analogies of, 52. Ranella, 64. 297. Rapella, 82. 307. Reniella, 386. Reproduction, modes of testaceous, 29.54. Reptilia, analogy of Nudibranchia with, 50. Respiration of Testacea, &c., 29. 55. Siphonic organ of, 55. 111. Rhinoclavis, 157. 315. Rhinodomus, 80. 305. Rhodostoma, 208. 34M- Ricinula, 72. Planospira, 73. Cha- racters of, 300. Rimula, 243. 356. ' Rissoa, 343. Rostellaria, 138. 310. Elegance of their form, 140. R. rectirostris, of great rarity, 141. 146. R. curvi- rostris, 141. R. fissurella, 141. R. columbata, 141. R. macro- ptera, 144. R. cancellatus, 146. R. canalis, 146. Analogies of the group, 145. Species of, 145. Rotella, 213. 222. 227. 353. Rotellinae,213.222. 353. Rotifera, are prototypes of the Ra- diata, 4. n. Sanguinolaria, 366. Saxicava, 376. Saxicavidae, 257. 259. 375. Scabricola, 319. Scalaria pretiosa, 82. 185. 343. Cir- cular mouth of, 207. Scaphella, genus, 100. Types of, 123. 318. Connection with Volu- tilithes, 124. Forms a circular group, 125. S. maculata, 101. S. fulgetrum," 101. S. fusiformis, 103. 108. 123. S. papillaris, 103. 108. S, undulata, 107. 123. S. pa- pillosa, 108. 123.' Scaphula, 132. 322. Scarabus, 196. 208, 209. 344. Schizodesma, 368. Scissurella, 209. 344. Sowerby's fi- gures of, 209. Scolymina;, 75. 78. The circle of, perfect, 81. 95. Classification of the genera, 304. Scolymus, 77. 115. S. umbilicaris, 80. Characters and species of, 304. Scorpions, observation on, 53. Scutibranchia, of Cuvier, 25. 47. 358. Respiration of the, 57. In- ternal structure, 57. 60. 239. Divisions of, 240. Circle of, 245. Sea eggs, or Echinida, 5. Senectina?, or snake-shells, 212. 214. 348. Analogies of, 224. Senectus, 206. 213. Species of, 215. 348. Shells and shell-fish, Q,et seq. Study of, important to geology, 9. Science looks to the animal rather than its shelly domicile, 10. On what principle cabinets should be arranged, 10. Modifications of the forms of, 11. New shells im- ported, 17. Habits of the animals investigated, 17. Desiderata as to plates representing, 19. Divi- sions and analogies of, 26. Struc- ture of, 27. Locomotion of, 30. Permanent habitat of, 32. River, 33. Land, 33. 56. Gastropod, 53. Spiral, 62. The Helicida; de- scribed, 160. Marine, 195. 206. River bivalves, 259. et passim. Systematic arrangement of, 295. Explanation of terms, 391. Sigaretus, animal of the, 229. 234. 241. 345. Sigaret of Tonga, 235. Siliquaria, 362. Siphonaria, 58. 245. 357. Siphonostoma, 333. Skin, of Testacea, resembles a man- tle, 29. Slugs, terrestrial and fluviatile, 25. 30. Description of, 35. 45. 55. Mantle of, 56. Respiration of, 56. Structure of, 162. Oceanic, 238. Classification of, 327. Snails, account of, 25. 55. 164. Uni- valve, 27- Head and eyes of, 33. Food of, 33. Minute testaceous, described, 45. Respiratory per- foration in the mantle, 56. Land and freshwater, 59. 158. The pre-eminent type of phytopha- gous Gasteropoda, 160. Families INDEX. 41? arranged, 162. See Helix and Helicidae. The lamp snails, 190. Oceanic, 31. 195.210, et seq. Clas- sification of, 326. 328. Solarium, 213. 217. 221. 352. Solen, 365. Solenella, 366. Solenina?, sub-family, 365. Solenocurtis, 366. Solenymia, 366. Spiders, observation on, 53. Spirorbis, 337. Spondylus, 32. 388. Starfish, of the class Radiata, 5. Stenopsis, of Guilding, 328. Stenopus, 190. The animal figured 190. Stomatella, 231. S. duplicata, 233. Stomatia, 229. Description of, 230. 354. Types of, 231. Analogies of, 232. 234. ' Streptaxis, 165 331. Strepsidura, 90. 94. 308. Strigatella, 131. 319. StrombidcE, have full} developed eyes, 33. 47. 55. Wing-shells, 63. Respiratory siphon of, 111. Predacious, 136. Sub-families of, 143. Typical genera of, 152. 156.309. Analogies of, 154. Strombidea, 138. 140. 146. 310. Strombina?, true wing-shells, 138. 309. Genera of, 138, 139. 145. Affinities of, 138. 142. Analo- gies of, 140. 143. Strombus, tuberculated, 116. Lobe of the genuine, 121. 123. Typical of the class, 136. S. pes-pelicani, 137. 141. S. sinuatus, 138. S. latissimus, 138. S. melanosto- mus, 139. S. pacificus, 139. S. gigas, pink-mouthed, 139. 144. S. granulatus, 139. S. goliathus, the largest lip of the genus, 139. S. gibberulus, 140. 144. S. Lu- huanus, 140. 143. S. Auris- Dianse, 139. 144, 145. S. sue- cinctus, 144. S. lentiginosus, 139. 144. Analogies of the types of the genus, 145. The strombi- form structure, a primary type, 154. 310. Struthiolaria, 81. Relation to Mu- rex, 83. Characters of, 306. Stuchbury, Mr., 71. n. Succinea, 190. 189. 328. Sun-shells, 216. Swimming of molluscous animals, 31. Symphynota compressa, 280. 287. Systematic and natural arrange- ment; forming Part II. of this work, 295. T. Taenioides of Cuvier, comprehended in the annulose circle, 44. Tape-worms, 44. Tectibranchia, comprehend Bulla and Aplysia, 25. 35. Form and habits of, 36. Shells hid in the flesh, 55. Natural group of, 58. 247. Naked order of, 236. Ana- logies of, 237. Representations of, 238. Circular succession and analogies of, clearly developed, 248. Classification of, 361. Tellina, 371. Tellinidse, 260. 369. Tellininze, sub-family, 370. Terebellum, 137. 146. 310. Terebra, 302. Long spire of the group, 74. 131. T. vittata, 74. T. maculata, 302. Terebralia, 157. 315. Terebratulse, 32. Processes of, to capture prey, 34. Teredina, 364. Teredo, 257. 364. Terms used in conchology, 391. Testacea, the, 3. Are a popularly interesting class of molluscous animals, 3. The typical Testacea provided with eyes, 8. The most perfect of the Mollusca, 8. Ar- rangement of species of, 9. Groups of the typical, as discriminated by Aristotle, 13. Arrangement of, by various modern naturalists, 41, et seq. Of the Caribbean seas, 17. Difference of the animals confirms the recognised charac- teristics of their shells, 18. Na- tural disposition of the class, 19. Table of, 20. Order I., the Ma- rine, 20. Order II., the Fluvi- atile, 21. Order III., Terrestrial, 21 Merits of Lamarck and Cu- vier's classifications of, 26. Ana- logies of, 26. Typical character- istics of, 27.; positive and ne- gative, 28. Considered anato- mically^. Blood white, 28. ; its circulation double, 29. Respir- ation, 29. 55. Reproduction, 29. 54. Deglutition, 29. Operculum, 97. Nervous system of, 29. Mode of progression of, 30. Power of saltation, 30. Adhesion, 31. De- fect of power of locomotion, 32. Perforation of a permanent re- sidence, 27. 32. Some cemented to fixed or floating substances, 32. Head, eyes, and tentacula of, 33. Habits, food, and geographic dis- tribution, 33, 34. 97. Primary divisions of, 35. Gigantic genera of, known only from tradition, 39. 418 INDEX. Great circle of, 44. 46. Orders of, 49. Analogies of, 52. A single grand genus, Testacea, imagined, 92. Families of exquisite spiral, 97. Series of fluviatile, 204. &c. Testacella, 327. Tethys, 24, 25. Textilia, 312. Thallepus, 251. 359. T. ornatus, 251,'n. Thallicera, 196. 339. T. avellana, 196. Analogies of, 210. Theliconus, 312. Theliderma, 268. 272. 377. T. irrorata, nodosa, " cylindrica, pustulata, plicata, 272. T. cylin- drica, 274. T. Peruviana, 276. Analogies of the sectional types of, 273 Thelidomus, 191. 194. Description of, 228. 332. 353. TheJidonta, 193, 194. Thracia, 376. Tiara, typical form, 97. 319. 322. Real type of Mitrinas, 112. 129. Analogies of, 130. 319. T. tere- bralis, 131. Sub-genera of, 320. Tiarella, 131. 319. Timorenia, 38. Tomella, 155. 314. Tornatella, 207. 343. Trachelipoda, of Lamarck, 24. Tremadotes of Rudolphi, 46. Trichopodus, 211. Tridacna, 257. 374. Trigonia, 383. Triphorus, 342. Triton, genus, 24, 25. The naked, 31. Swims in search of its prey, 3*. Description of, 36. 50. 64. 297. T. clandestinum, 75. Tritonidea, 74. Remarks upon cha- racters of, 74. 302. Trivea, 135. 325. Trochatella, 337. Troch4lla,59.355. Trochia, 74 302. Trochidae, are marine, 159. 211. Genera of, 207. Habits of, 212. Shells perlaceous, 212. Pyra- midal, 212. Sub-families of, 213. Analogies with those of Turbi- d«e, 223. ; with the Achatinae, 226. Family of, 347. Trochidon, 351. Trochina?, described, 213. Oper- culum horny, 216. Genera and analogies of, 224. Sub-family, 349. Trochus, of Linnaeus, 25. 350, 351. Spiral, 47. Horny operculum of, 213. T. Niloticus, 216. T. zizy- phinus, 218. T. merula, 219. Strawberry, 220. Analogies of, Tropics, the, Testacea of, 34. 147. Truncatella, analogies of, 209. 343. ; Tubicanthus, 349. Tubulibranchia, comprehend Ver- metus, Magilis, and Siliquaria, 25. Structure of, 36. 47. 54. 134. • 256. Characters of the tribe, 258. Systematic arrangement of, 361. Tuliparia, 311. Turbidae, family and circle of, 44. 341. The animals alone offer the characters of, 160. Shells spiral, with an operculum, and without pearly lustre, 195, Typical ge- nera of, 223. Turbinae, or winkles, 195. Analo- gies of, 210. Characters of the genera, 342. Turbinella, typical genus, 76. 94. 303. Fossil Clavalithes, 77. T. Scolymus, 78. T. rapa, 78. Turbinellidae, characteristics of shell of, 75. 303. Sub-families of, 75. 243. Sub-typical group, spiny and coronated, 115. Analogies to the Cassidae, 89. Affinities to the Muricidae, 95. Turbinellinae, 'smooth and heavy shells of, 75. Analogies of Fusinae and, 93. Arrangement, &c., 303. Turbo, of Linnasus, animal' of, 25. 207. 345. Phytophagous and also zoophagous, 47. Possesses a si- phon, 160. 206. Figure of, 207. T. sarmaticus, 213. .T. Nicoba- ricus, 222. Turritella, resemblance with Tere- bra, 74. 131. A typical genus, 206. Long-spired, 223. Charac- ters of, 343. U. Umbrella, 62. 253. 361. Ungulina, 259.371. Unio circulus, 261. U. gigas, 263. 275. U. margaritifera, 263. U. cuneatus, 263. U. Esopus, 263. 271. U. mytiloides, 268. 270, 271. 292. U. torsus, 270. U. recta, 268. 272. U. cylindricus, 273. 276. U. alata, 279. U. nasutus, 279. U. truncatus, 270. U. no- dosa, 270. U. obliqua, 270. U. rugosus, 273. U. elongata, 275. U. radiatus, 276. U. marginata, 278. U. fragilis, 279. U. Austra- lis, 285. The typical, 264. Its umbones, or bosses, 265. Distinct types of, 268. 377. Analogies of sub-genera of, 269. 274. Climate inhabited by, 283. Unionidae, the, 257. 260. 264. 282. n. Primary divisions of, 264. 377. INDEX. 419 Principle of variation in these shells, 262. Modifications of, 290. Station of the family of, 262. Analogies of the genera of, 267. Inexhaustible profusion of, 292. Unionina?, the, 265. Characters of, 275. 377. Analogies of, 285. Uniopsis, figure of, 288. 382. U. ra- diata, 289. Univalve shell-fish, 21. 27. 30. Spi- ral, 34. et passim. V. Valvata, 185. 196. 198. 339. Velotes,347. Velutina, 235. 355. Venerina?, sub-family, 371. Venerupes, 376. Venus, 372. Verm.es, annulose or intestinal, 27. 44. 52. True, completely articu- lated, 38. Vermetus, 362. Vermillia, 362. Vertebrata, allusions to the, 1. 2. 4. 116. Connecting link of the Mol- lusca with the Cephalopoda, or cuttlefish, 5, 6. 33. Theory re- specting the, 42—44. 50. Circle of the, 49. Vertego, 183. Vesica, 360. Vexilla, 69. 300. Vitrella, 360. Vitrina, 190. 3.28. Vitularia, 297. Voluta, of Linnaeus, 316. V. zebra, 101. V. olla, 102. V. Neptuni, 104. 113. 116. V. angulata, 105. V. magnifica, 105. V. mitis, 105. V. ancilla, 106. V. scapha, 105. V. fulgetrum, 108. 124. Generic character, a large spire, 108. Af- finities and distribution, 101— 111 . Generic types of this genus, 113. 316. Circles of, 113. Analogies of, 114. V. imperialis, and bat volutes, 114. Coronated volutes, 115. Melons, or typical volutes, 67. £9. 105. 111. 117. V. Brode- ripia remarks upon, 105. 117. V. Cymbium, 104. 117. V. vEthi- op'ica, 117. V. musicalis, 122. V. fulgens, 125. The terrestrial vo- lutes, 162. 190. 192. Volutella, 323. Volutidas, or volutes, 63.76. Pri- mary groups of, 98. 112. Analogy to Zoophaga, 99. 117. ; and Cas- sidae, 100. Circle of affinity per. feet, 101. Analogy ofVolutina? _ with, 112. ; of the Muricida? with, 112. General analogies of, 132. ; to vertebrated and annulose ani- mals, 134. Classification of, 31 6. Volutilithes, genus, 105. 112. 318. Typical conformation of, 121. V. musicata, 115. V. costaria, 121. 125. V. angulata, 122. V. ci- thera, 122. V. rarispina, 123, 124. Analogies of, 122. Sub-generic types of, 122. 318. Volutinze, are the typical volutes, 98. 316. Genera of, 112. Ana- logies of, 112. 122. 129. Volvaria, 134. 326. Vulsella, 386. W. Wentle-trap, common, 207. West Indies, Testacea, &c. of the, 17. 45. 180. 182. 192. 209. Wheel-shells, 213. Winkles, or Turbina?, 195. Wood's Catalogue, 19. Worms, red-blooded, 7, 44. Gas- tropod, 33. X. Xylophaga, 364. Z. Zoanthus, a genus connected with Radiata, 6. Zonites, 177. 227. 331. Zoology, arranged on a new basis, 3. Aristotle established the first prin- ciples of, 13. Zoophaga, the, perfection of sight of, 8. Table of, 24. Carnivorous shell-fish, 55. Respiratory siphon of, 55. Eyes and tentacula, 55. Mouth, 55. Tongue, 56. Sexes, 56. Operculum, 56. Genera of, 56. Distinctions of, 59. 61. Di- visions of, 62. 83. 97. Analogies of, 99. Point of union with the tribe Phytophaga, 158. Families of, 160. The tribe arranged, 295. Zoophytes, the true Acrita are con- sidered as compound, 4. n. THE END. LONDON : Printed by A. SPOTTTSWOODE, New-StreeUSquare. RETURN EARTH SCIENCES LIBRARY TO— ^ 230 Earth Sciences Bldg. 642-^ LOAN PERIOD 1' 14£**S • "7 DAYS 3 -^^\x*x>^S>r^S^vsXr"vX' 5 6 ALL BOOKS MAY BE RECALLED AFTER 7 DAY Books needed for class reserve are subject to immediate r DUE AS STAMPED BELOW AUG 81985 MAY 1 m •W:r 1 fl 1QQ6 NOV 11898 UNIVERSITY OF CALIFORNIA FORM NO. DD8, 7m, 12/80 BERKELEY, CA 9472 ^^