164 VOLUTIDA. 
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. vespertilio, Linn. (iii, 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. V. imperialis, Lam. (lili, 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, (lili, 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 pliez. 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, subeylindrical, 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 (lili, 14, 15). 
PSEPHA, Crosse, Shell oblong-fusiform, very finely trans- 
versely striated and furnished with longitudinal ribs, disappearing 
towards the middle of the last whorl. Nucleus (?). Columella 
furnished with two principal plice, above which there are two or 
three minute ones hardly visible; it presents also this peculiarity 
(in the adult shell), that these plicge are situated so far within as 
to be invisible when the shell is placed right in face of the 
e, 
