10 
H. MiNUTA. — Shell rather thick; spire convex, little elevated, 
with three volutions ; suture well defined, impressed ; whorls 
obtusely wrinkled across ; aperture nearly orbicular ; lip much 
thickened, reflected, white, distant from the umbilicus ; umbilicus 
large, exhibiting the volutions. Breadth less than one-tenth of 
an inch. Found under the bark of a decaying oak ; is readily dis- 
tinguishable from other species by its small size and conspicuous 
lip. 
H. LABYRiNTHicA. — Shell conic, dark reddish brown, body 
lighter ; whorls five or six, with conspicuous, elevated, equidis- 
tant, obtuse lines across, forming grooves between them ; apex 
obtuse, lip reflected, rounded ; pillar-lip with a large, lamelliform, 
elongated tooth, which appears to revolve within the shell, parallel 
to the suture ; a smaller raised line revolves nearer to the base 
within the shell, but becomes obsolete before it arrives at the 
pillar-lip; umbilicus rather large. Breadth one-tenth of an inch. 
Found on fungus in decaying wood. This shell is remarkable 
for the two much elevated lines, which revolve within the shell 
upon the penultimate whorl, the upper one larger, and terminating 
at the aperture very conspicuously, and resembling a tooth. 
Genus Polygyra. — Sa^. 
Journal Acad, vol i. p. 276, anno, May, ISIS. 
Shell discoidal, more or less carinated on the upper edge of the 
whorls, umbilicated ; aperture longer than broad ; lips thickened, 
toothed, or folded and continued, folds concave beneath ; pillar-lip 
raised above the preceding whorl and concave beneath. 
Animal granulated, tentacula four, eyes at the tip of the supe- 
rior tentacula and retractile ; operculum none. 
P. AURicuLATA. — Shell beneath, convex ; whorls five, a little 
rounded, crossed by numerous raised equidistant lines, forming 
grooves between them; spire very little raised; lateral line (ex- 
tending from the outer whorl to the apex) not convex, but some- 
what concave ; mouth very unequal, lips prominent above, ad- 
pressed to the preceding whorl beneath ; pillar lip suddenly re- 
flected, and pressed into the mouth at an acute angle, beneath 
very acutely concave ; outer lip a little more prominent in the 
middle, and within the edge protruded into the mouth ; throat 
extremely narrow ; suture near the mouth suddenly reflected from 
