38 



coating of enamel, and the growth of the shell is completed by a light 

 fabric of colouring matter deposed in lines, blotches, waves, or reticulations, 

 of various hues and patterns. These are not, however, the only physiolo- 

 gical changes that take place in the Cowrey. From observations made by 

 a gentleman who worthily employs the opportunities afforded him, as a 

 Naval officer, in the pursuit of science, I have strong reasons for believing 

 that there is some truth in the argument set forth many years since by 

 Bruguiere and Lamarck, relative to the Cypraa possessing the faculty of 

 partially dissolving and renewing its shell after having arrived at maturity* 



Lamarck says in reference to the re-calcification of the Cypraa shell, " I 

 possess observations which tend to prove that the Cowrey, arrived at the 

 power of forming a complete shell, has still the faculty of enlarging its 

 habitation, and is then obliged to quit the shell in order to form a new one. 

 It results from tins that the same individual has the power of forming a 

 successive number of shells during both the second and third stages of 

 growth ; and which accounts for our often meeting with so many different 

 sizes in the same species " ! 



M. Deshayes argues against the possibility of an entire re-modelling of 

 the shell, and justly regards the statement of Lamarck as a theory opposed 

 to the common laws of organization. To the supposition of Bruguiere 

 that the Cowries cast their shells after the manner of Crabs, M. Des- 

 hayes very properly replies that there can be no analogy between them. 

 The new shell of the Crustacea is formed by a secretion of equal consistency 

 from all parts of the body, whereas the Mottasca have a muscular attach- 

 ment to the columella, and increase the growth of their shell by an exuda- 

 tion, not from the whole body, but from a particular organ ; the mantle 

 being the sole agent charged with that faculty. It is further argued by the 

 same distinguished naturalist that the Cowrey must lose the power of form- 

 ing the inner chambers of the columella anew, after having once passed 

 that early process of development winch induces their formation. " How 

 is it possible/' asks M. Deshayes, " that the animal can, under the circum- 



* Lieut. J". B. Hankey, R.N., to Lovell Reeve. 



Will you allow me to offer you a few remarks on the habits of the Cyprsea as regards the fact 

 of its making 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 Cowrey crawl into some hollow or sheltered place, 

 evidently for some predetermined purpose, The growth of the animal appeal's to increase too 

 large for its cell ; it gradually swells and cracks the shell, and I flunk that some powerful solvent 

 or decomposing fluid is distributed over the outer surface by the mantle of the tish, for it gets 

 thinner in substance, and the colours duller in appearance. The shell then entirely disappears, 

 the Cowrey becomes, to all appearance, a naked mollusk, with no other covering than its mem- 

 branous mantle, and in a short time secretes a thin layer of glutinous matter which in a few days 

 obtains the fragile consistency of shell-lac. From this step its growth is more rapid, and it 

 becomes more aud more consolidated iuto the adult shell. When iu the first stage of renewal it 

 lias the appearance of shell-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 fragility. 



H.M.S. Colliugwood, August 6th, 1844. J.B. H. 



Conchologia Iconica, Cyf&sa Plate I. 



