YOLUTA. 289 



VIRGULINA. D'Orb. A genus of microscopic Foraminifera. 



VITRELLA. Sw. A sub-genus of « Bulling," Sw. Lardn. Cy- 

 clop. Malac. p. 360. 



VITRINA. Drap. (Vitreus, glassy.) Fam. Limacinea, Lam. and 

 Bl. — Descr. Ovate, thin, glassy, fragile ; spire short ; last whorl 

 large ; aperture wide, transverse ; peritreme simple ; columella 

 spiral, linear. — Obs. This genus of land-shells is not known in a 

 fossil state. The recent species are found among moss and grass, 

 in shady situations. De Ferussac has divided this genus into 

 Helicolimax, fig. 263, and Helixarion, fig. 262. 



VITULARIA. Sw. A genus of "Muricinse," Sw. thus described: 

 " General habit of Muricidea, but the inner lip is depressed and 

 flattened as in the Purpurince ; varices simple, nearly obsolete. 

 Tuberculata, Siv. En. M. 419. fig. 1. (Murex vitulinus, Auct.)" 

 Sw. p. 297. 



VIVIPARA. A generic name given by Montfort, and retained by 

 some authors for Paludina, Lam. on account of the animals 

 being viviparous, i. e. the young being perfectly formed before 

 they leave the ovaries. 



VIVIPAROUS. See Vivipara. 



VOLUTA. Auct. (Volvo, to revolve.) Fam* Columellaria, Lani, 

 Angyostomata, Bl. — Descr. Sub-ovate, rather angulated, thick, 

 generally tuberculated, smooth ; spire short, conical, with a 

 mammillated apex ; aperture generally angulated, large, terminat- 

 ing anteriorly in a deep notch ; columella smooth, with several 

 plaits, of which the lowest is the largest ; outer lip thickened 

 within.— Obs. The genus Voluta, as left by Linnseus, is only cha- 

 racterized by the folds on the columella, and includes many 

 shells which, although they agree in this respect with the genus, 

 are yet quite opposite to each other in all other characters. Thus 

 the Auriculae, which are land shells, and have the aperture entire, 

 are mixed up with others which are marine, and have a canal, as 

 Turbinellse, and the Fasciolarise, and others which have merely 

 a notch, as the true Volutes. This genus, as it is circumscribed 

 at present, includes a great number of beautiful shells, most of 



u 



