CYPR^A.— Plate I. 



It is, however, certain that the Cowry is enabled to 

 effect a very important change in the shell during one or 

 more periods of its life ; and I think the fact may be fully 

 established without prejudice to the excellent arguments 

 of my illustrious contemporary. Prom the testimony of a 

 gentleman, who worthily employs the opportunities aiforded 

 him as a Naval Officer to the advancement of science, 

 whose veracity is beyond all question, and whose com- 

 mimication ( given verbatim ) * contains nothing more 

 than a simple naiTative of the phenomena of which he was 

 himself an eye-witness, it may, I think, be deduced that it is 

 the outer wall of the shell only which is re-constructed, 

 the columella with its spiral compartments remaining un- 

 distm'bed. The animal does not quit the shell as Lamarck 

 supposed, but dissolves the outer portion with its acetose 

 juices. All visible trace of the shell may be thus removed 

 without weakening M. Deshayes' proposition founded on 

 the circumstance of the mantle being the only organ 

 chai'ged with the secretive fluid. The mantle is always 

 capable of extension over the shell ; and the same power 

 which furnishes the adult with its last coating of enamel 

 can be exerted to the foimation of as many superincum- 

 bent layers as may be necessary to replace all that has 

 been decomposed. That a dissolution takes place there 

 can be no doubt : — " the shell gi-aduaUy swells," says 

 Lieut. Hankey, " and cracks, becomes thinner, and duller 

 in colom', and finally disappears ;" a circumstance which 

 may be easily credited when it is remembered that the 

 Murex possesses the facidty of removing spines or any 

 similar obstacles to its advancement of growth, and that 

 the Pholades, and other terebrating moUusks, exercise a 

 power of absorbing which enables them to penetrate the 

 hardest limestone rock. The microscopical stnictm-e of 

 the Cowry shell is, moreover, of a natm-e peculiarly tena- 

 cious of absoi-ption ; it is composed of a lai'ge quantity of 

 carbonate of lime in proportion to the amoimt of mem- 

 branous substance; and this accomits for its surface be- 



coming vitrified, as it were, to such a highly polished state 

 of enamel when in contact with the acidity of the soft 

 parts. 



There is another circumstance in Lieut. Hankey's nar- 

 rative to which attention shoidd be given, respecting the 

 formation of the new shell : — the glutinous matter which 

 has the appearance of sheU-lac, and is so fragile that it 

 jdelds to the touch, does not assume the nan-ow cylindrical 

 Bulla form, it does not follow the original plan of revolv- 

 ing round a columellar axis, but is of the ^vide, ventri- 

 cose shape of a Cymba, and rapidly consolidates into the 

 adidt shell. 



With these generalizations I think it may be assimied 

 that the Cowry possesses the faculty of decomposing, 

 during one or more periods of its existence, any portion 

 of the shell that is liable to resist its advancement of 

 gi'owth ; that the renewal of the shell is accomplished 

 within a comparatively short space of time ; and that the 

 coliuneUa with its internal spii-al partitions remains undis- 

 turbed. It may, however, be infen-ed that it is an opera- 

 tion of extremely rare occun'ence, and one which only hap- 

 pens mider peculiar conditions. 



The CyprcecB present two very distinct groups ; — the 

 larger species in which the smface of the shell is highly 

 enamelled, and the smaller species in wliich it is dis- 

 posed in grooves and ridges of a lighter character and of 

 more debcate colouring. In the first division there are two 

 or tlu'ee species from South Africa of a pecuHar opake 

 white structiu-e, of which the C. Algoemh and Capemis 

 may be quoted as being the types of Mr. Gray's genera 

 Liiponia and Cypraovula; the second cbvision is the genus 

 Trivia of the same writer. 



The genus Cyprtea presents Kttle variety of form but a 

 tbversity of coloming ; it contains several very tUstinct 

 and characteristic species of unusual rarity, and which our 

 country can alone boast of possessing. Of these the 

 Cyprcca princeps and leucodon, in our national collection, 



* Lieut. J. B. Hanket, R.N., to Lovell Reeve. 

 My dear Sir. 



H.M.S. Collingwood, August 6tli, 1844. 

 ^Yill you allow mc to offer you a few remarks on the habits of the Cypra;a as regards the fact of its maldng a new shell, at an advanced 

 age, of which process I have been myself in more than one instance an eye-witness. I have seen the ConTy crawl into some hoUow or sheltered 

 place, evidentfy for some predetermined purpose. The gron-th of the animal appears to increase too lai-ge for its ceU ; it gradually swells and 

 cracks the shell, and I think that some powerful solvent or decomposing fluid is distributed over the outer surface by the mantle of the fish, 

 for it gets thiuuer in substance, and the colours duller in appearance. The shell then entirely disappeaj-s, the Cowiy becomes, to all appeai-anee, 

 a naked moUusk, with no other covering than its membranous mantle, and in a short time secretes a thin layer of glutinous matter which in 

 a tew days obtains the fi'agile consistency of sheU-lac. From tliis step its growth is more rapid, and it becomes more and more consoli- 

 dated into the adult shcU. When in the first stage of renewal it has the appearance of sheU-lac it is always of the Cymba form, but I have 

 never succeeded in preserving any specimens in this state on account of their extreme fi-agility. 



Trasting that you may make some use of these notes, and that (as I have a good dredge with me) I may, like Mr. Cuming, succeed in bringing 

 home something worthy of notice, I shall couclude myself, my dear sir. Yours veiy tridy, 



John B. IIanket. 



