66 BOOK OF SPECIES. 
and girded with a white line at its sutures. W. 
29. 56. 
ROTELLA. 
Orbicular, shining, devoid of epidermis ; spire ex- 
tremely short, sub-conoid ; lower face of the shell 
convex, and callous ; mouth half-rounded. 
R. ~tingouata. Conical- convex, smooth, 
with a gibbous callosity on the base, and the aper- 
ture somewhat heart-shaped; varying in colour, 
and markings often obliquely rayed. Sow. 357. 
TROCHUS. 
Conical, spire elevated, sometimes abbreviated ; 
aperture transversely depressed; margin of 
outer lip disunited from the body at the upper 
part ; columella arcuated, more or less oblique 
at the base; operculum horny. 
S. AGGLUTINANS. Conical, sub-umbilicated, 
coarse, obtusely plaited, semi-pellucid, dirty white, 
and the whorls tiled ; base concave, and the pillar- 
lip sickle-shaped. Attaches to itself stones, &c. 
Diam. 14. W. 29. 69. 
T. ca@xiatus. Sub-conical, with oblique 
somewhat scaly plaits on the upper part, and 
transverse spinous ribs at the base of the whorls, 
green or greenish white; base covered with con- 
centric rows of small umbricated scales; pillar 
