387 
they become nearly obsolete ; straight, entire, not fureate ; long 
and short ribs alternating. Back broad, anterior and posterior 
third convex; middle third concave, anterior third, studded with 
small tubercles. Tubercles on anterior and posterior thirds of 
carine small, nearly obsolete: on the middle third of each carina, 
seven very large tubercles, broad at the base; compressed laterally 
near the apex ; terminating in an acute edge, curving outwardly. 
Sinus furnished with a thick callus continued to the margin of 
the lip. Lips convex. Aperture subquadrate oblong ; narrowing 
somewhat anteriorly. Angles acute; spineless; everted. An- 
terior half of the shell milk white, except near the sinus, where 
it is pale purple; posterior half pale fuscous. Subsinus, carine, 
and large tubercles, dark fuscous; a white, longitudinal, central 
line running through it, between carine. Anterior half of shell 
polished, remainder dull. 
ength, 23 inches. Breadth, 1} inches. Aperture : ami 
li inches ; width, 1 inch. Obtained at New Nantucket, Pacific 
Ocean. 
I have named this shell after the distinguished T. A. Conrad, 
Whose labors in the Testaceological field are well known and 
universally appreciated. 
No. 2. A. Fragilis.— Oblong ovate, very thin, frail, sides 
Smooth, without granulations, having numerous opaque, minote 
milk-white spots distributed over them ; ribs numerous, inter- 
rupted, a few entire; subfurcate, somewhat waved. Back — 
flat. Tubercles many; rather small; generally of a size. Sings 
large, furnished with a callus, which is attenuated towards the 
edge of the lip, and is carried across the base of the aperture, 
from one sinus fo the opposite, in a flattened arch ; wm dn 3 : r ; 
arch rests one side of the nucleus of the shell; which is NOT IN- 
ch 
VOLUTED hike other species, but rises in a cylindrical form, o 
inch above the arch from which the inner side springs; it has 
much the appearance, in shape, of the end of the finger of a 
glove. Around this cylinder are a number of lines of growth ; 
(o Otherwise it iş smooth, somewkat waved, and destitute of tuber- 
d cles for the distance of i inch from the apex; lips eonvex. 
Aperture, ovate oblong. | : 
