10 



11. jnNUTA. — Shell ratlier tliick ; 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, lamilliform, 

 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 whoi-1, the upper one larger, and terminating 

 at the aperture very conspicuously, and resembling a tooth. 



Genus Polygyra. — Say. 



Journal Acad, vol i. p. 276, anno, May, 1818. 



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 whoi'l 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- 

 prcssed 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 Avithin the edge protruded into the mouth ; throat 

 extremely narrow ; suture near the mouth suddenly reflected from 



