164 VOLUTID^, 



moderately elongated, terminated by a papillary summit with 

 the apex lateral, instead of central and vertical as usual in spiral 

 shells ; surface plicate longitudinally, crossed by engraved 

 revolving lines ; columellar plaits six or seven, or more ; lip 

 thickened within, its margin slightly crenulate. V. rupestris, 

 Gmelin (liii, 8). 



VESPERTiLio, Klein, Shell oval-oblong, more or less ventricose. 

 Spire terminated by a regularly spiral summit, papilliform, but 

 having an apparently crenulated nucleus, caused by the presence 

 of numerous little tubercles, more or less apparent. Columella 

 four-plaited. V. vespe7-tilio, Linn, (liii, 9). 



AULiCA, H. and A. Adams. Agreeing with the preceding sec- 

 tion in general form and principal characters, the summit of the 

 spire differs in having a completely smooth instead of a tuber- 

 culated surface. F. imperialism Lam. (liii, 10). 



AMORiA, Gray. Shell fusiform, smooth and polished ; spire 

 conical, with a small, more or less pointed nucleus ; sutures 

 slightly callous ; columella with five oblique, more or less devel- 

 oped plaits. V. undulata^ Lam. (liii, 11). 



ALCiTHOE, H. and A. Adams. Shell oval -fusiform, spire elon- 

 gated, terminated by a papilliform summit; aperture oval- 

 elongated, inner lip covered by a callous deposit, outer lip 

 expanded and more or less reflected; columella with four, and 

 more rarely five to seven oblique plicae. V. Pacifica^ Solander 

 (liii, 12). 



CYMBiOLA, Swainson. Shell oval, thin, recalling the form of 

 Cymbium. Spire more or less elongated, terminated by a slight 

 irregular, papilliform summit. Aperture large, the columellar 

 side covered with a slight coat of enamel ; columella usually 

 with four oblique plications ; outer lip sharp, occasionally^ 

 slightly expanded. An American, and principally Antarctic 

 group. V. ancilla, Solander (liii, 13). 



VOLUTELLA, d'Orbigny. Shell smooth, subcylindrical, with 

 angulated whorls; spire acuminated, polished, and entirely 

 covered by an enamel deposit, obliterating the suture-line more 

 or less entirely ; columella with three oblique plaits ; lip sharp, 

 not reflected. The development of a lobe of the mantle to cover 

 the spire is a peculiarity in this animal not shared by the other 

 groups of the genus. V. angulata, Swainson (liii, 14, 15). 



PSEPH^A, Crosse. Shell oblong-fusiform, very finel}^ trans- 

 versely striated and furnished with longitudinal ribs, disappearing 

 towards the middle of the last whorl. Nucleus (?). Columella 

 furnished with two principal plicae, above which there are two or 

 three minute ones hardl}' visible ; it presents also this peculiarity 

 (in the adult shell), that these plicae are situated so far within as 

 to be invisible when the shell is placed right in face of the 



