v £y 
inhabiting the United State. Wi 
lip simple, thin at its edge, ` ened within ; base 
. rather convex, near the aperture opake, yellowish 
white ; umbilicus small, but rounded and distinct in 
young shells, obsolete or hardly apparent in older 
ones ; within the aperture on the outer lip is a single 
lamelliform, elongated, oblique tooth. 
Greatest transverse diameter nearly one fourth of 
an inch. 
GEOGRAPHICAL Fatri Inhabits Ohio and 
Pennsylvania, and without doubt may be found in 
other States. 
Remarks. This shell does not correspond ex- 
actly with Say’s description, but I think it is the 
same that he described under the same name. Hav- 
ing received from Dr. Ward, of Roscoe, Ohio, a suite 
of them of different sizes, I notice that the *umbili- 
cus small, orbicular, profound,” of Say, exists only 
in young specimens, it being closed in the elder. 
The indentation of the umbilical region is not nf 
nt to me. 
It resembles very much the preceding species, Es 
has one whorl less, is more depressed, and its base is 
more convex. The tooth in the aperture is some- 
times so little prominent as to be hardly visible. 
The strie of growth are fine and crowded, and seem 
to be more nearly at right angles with the suture 
than is usual in other species. 
