698 Character of Pelagian Shells. [Dec. 



VII. — Corrected Character of the Genus Cuvieria of Rang, and notice 

 of a second species inhabiting the Tropical Indian Ocean. By W. H. 

 Benson, Esq. B. C. S. 



In ray catalogue of Pelagian shells, vol. iv. p. 176, I mentioned 

 that the capture of perfect specimens of the Pteropodous genua 

 Cuvieria would enable me to correct the characters given by Rang, 

 in his Manuel, from shells met with in the imperfect state in which 

 they are usually found. I now redeem the promise implied in that 

 communication. The following is the corrected character. 



Cuvieria (Rang). Testa symmetrica, antic& subcylindricea, postice 

 elongato-conicet, apice acutissimo, medio septo tenui, iraperforato, 

 concavo, versus apicem convexo, concamerata; apertura supra depressa, 

 subcordiformi. 



Rang gives as a character " le cote 1 oppose a l'ouverture ferme par 

 un diaphragme convexe a l'exterieur, non terminal, (jtant ddborde 

 par les parois du cylindre,-" and this is the general appearance of the 

 shell, which in the numerous specimens captured by us, was, with 

 the exception of two individuals belonging to the smaller species 

 hereafter described, defective in the conical termination. One of 

 these two, taken in my tow-net, I broke on extracting the animal ; 

 the other, which was secured by Lieut. Hatton, H. M. 62nd regi- 

 ment, was kindly presented to me by him. 



The ordinary condition of Cuvieria appears to be analogous to the 

 truncation observable in Bulimus decollatus, and in some of the 

 Melania, in which the part excluded by a diaphragm is liable, from 

 the loss of vascular connexion with the inhabited part of the shell, to 

 become brittle and deciduous. 



The larger species, C. columnella of Rang, the only recent one 

 hitherto observed, is that which is most widely distributed, and was 

 met with by us in the Southern Atlantic, as well as in the Southern 

 Indian Ocean. The range of the smaller species, which differs in being 

 about half the length of the other, and in being somewhat more 

 depressed, and more ventricose laterally, appears to be more confined. 

 I shall describe it from its resemblance, in its ordinary mutilated state, 

 to a grain of rice, as 



C. Oryza. Testa laevi, intida, depresso-cylindrica, lateribus versus 

 septum ventricosioribus ; apice elongato, peracuto. 



Length T * 5 of an inch, of which the spire occupies nearly one-half. 

 Taken, from the 15th December, 1834, to the 1st January, 1835, in 

 a tract of the Tropical Indian Ocean contained between the parallels 

 of 8° 6' south and 5° 0' north, and between the meridians of 86° 38' 

 and 91° 0' east from London. 



