179 
TROCHUS laevigatus. 
TAB. OLXXXL— Fig. 2. 
Spec. Char, Conical, nearly smooth ; sides straight; 
base convex, with an obtuse margin ; aperture 
rhomboidal, with rounded angles. 
Height and width nearly equal ; the sides of the cone 
are almost straight, each whorl being very slightly con- 
vex : a few concave lines may be traced around the spire, 
they are obscure and irregular ; the lines of growth are 
very fine, and thus the surface appears smooth. The 
base of the columella is oblique, which gives the mouth 
a rhomboidal form, there is no umbilicus. 
This interesting Trochus nearly resembles T. ziziphi- 
nus, but is readily distinguished by its obtuse margin 
and plain surface. The specimen figured was presented 
me by Mrs. Cobbold, who found it in the Craig pits at 
Holy wells : the external coat has peeled olf in some parts, 
and exposes the pearly interior, whose pristine beauty 
may still be traced through the veil that time has cast 
over it in its subterranean cemetery. 
TROCHUS similis. 
TAB. CLXXXI.---f/g\ 2 , 
Spec. Char. Conical ; sides straight, ornamented 
with many transverse ridges, two or three of 
which upon each whorl are granulated ; base 
flattish, concentrically striated ; aperture qua- 
drangular ; columella direct. 
- -V- 
T he older shells of this species are rather wider than 
high ; the superior whorls overhang the inferior ones a 
