874 Mr. L. Eeeve on the Re-calcification of the Shell in Cyprsea. 



If therefore no specimen of Z. Blochii exists exceeding 1^ ft. in 

 length, httle doubt can remain that this species is Z. laticeps in 

 its foetal or very young state. 



In the principal part of this paper, viz. in the remarks on the 

 identity of Sphyrna Blochii with the foetal state of laticeps, Dr. Cantor 

 has been forestalled by Midler and Henlfe, who quote Dr. Cantor's 

 Zygana laticeps as a synonym of their Sphyrna Blochii. In another 

 point noticed in the commencement of the paper, viz. the identity of 

 the Koma sori^a of Russell with the Zygcena Tudes of Valenciennes, 

 Dr. Cantor differs from Miiller and Henfe, who refer Russell's figure 

 to the Sphyrna Zygtena or the malleus of Valenciennes, and their 

 authority is deservedly the highest as to Malacopterygian fish. The 

 fact however of the foetal fish with the head doubled back being 

 taken from the mother shark with the long transverse head of lati- 

 ceps is worth recording, as is also the habitat, for the range of 

 Sphyrna Blochii is not well known. — J. R. 



XLI. — On the Dissolution and Re-calcification of the Shell in 

 Cyprsea, a genus of Pectinibranchiate Mollusca. By Lovell 

 Reeve, A.L.S. &c.* 



The formation of a new shell in the Cowry at an advanced period 

 of its existence is a phsenomenon which modern naturalists have 

 hesitated to receive. Bruguiere first introduced the fact, but in 

 a manner which appeared to savour of the marvellous ; and even 

 Lamarck says, " I possess observations which tend to prove that 

 the Cowry, 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 

 this, that the same individual has the power of forming a suc- 

 cessive number of shells during both the second and third stages 

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

 different sizes of the same species f '' ! 



M. Deshayes, after furnishing us with an excellent account of 

 the zoological characters of Cyprcea^ derived mainly from the ob- 

 servations of MM. Quoy and Gaimard (Zoologie, Voyage de 

 F Astrolabe), argues against the possibility of any re-modelling of 

 the shell taking place, and regards the statement of Lamarck as 

 a theory opposed to the common laws of organization. To the 

 supposition of Bruguiere that the Cowines cast tlieir shells after 

 the manner of Crabs, M. Deshayes 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 



* Written for a forthcoming monograph of the genus Cyprtea in the 

 * Conchologia Iconica,' and communicated by the author, 

 f Animaux sana Vertebres (Deshayes* edit.), vol.x. p. 482. 



