VOLVARIA. 



Lam, — Syst. des Anim. sans vertebr. p. 95. 



— ^-^-^^ 



TESTA cylindrica, convoluta^ spird psene occulta ; 

 apertura longitudine testam sequans. angusta^ 

 versus basim expansior^ basi emarginata. Labium 

 externum denticulatum. ColumeUce basis plicata. 



Nearly related to some of the Linnean BuUce, particu- 

 larly in its general form, and in the circumstance of its 

 being transversely striated on the outside ; the plicae on the 

 base of the Columella at once distinguish it from them : 

 but not from some of the Lamarckian Marginellae, to which 

 also the Volvaria is nearly allied in shape ; it is not, how- 

 ever, in danger of being confounded with them, for we 

 believe the Marginellse never have less than four plicse on 

 the Columella, nor are they transversely striated on the 

 outside as the Volvaria is, but are polished shells, their 

 outer lip being thickened and reflected, and their animal 

 inhabitant having the power of extending its mantle so as 

 to cover the shell entirely. Of course we cannot say de- 

 cidedly that the animal of the Volvaria has not this power, 

 but if we are permitted in such a case to form our judg- 

 ment from analogy, we should say it has not, and we should 

 further without hesitation express our opinion that it has a 

 distinct epidermis. We are aware that in all we have 

 said above, we are at issue with the collection at the French 

 Museum ; but our opinion is formed upon the comparative 

 view we have taken of the species there arranged under 

 the generic term Volvaria^ with those of the Marginella ar d 

 Bulla, and we find them much more naturally related to 

 Marginella than to Volvaria. In the Annales du Museum, 

 Lamarck mentions his opinion that the Volvaria is related 



