cularly joined to the outer lip at the base. Outer lip reflected 

 back upon the whorl, and incorporated with it near the base, with 

 a deep sinus in the middle. Beneath, one quarter of an inch. 

 Lister, Tab. 93, f. 94 ? 



Inhabits moist places ; common. In the collection of the Aca- 

 demy. This species appears to be somewhat allied to H. hispida, 

 but is sufficiently distinct. Found by Mr. Lardner Yanuxcm. 



H. PERSPECTIVA. — Shell very much depressed, with about six 

 whorls ; whorls striated across, with raised, parallel, acute lines, 

 forming strongly impressed sulcai between them. Umbilicus very 

 large, resembling an inverted spire, in diameter at least equal to 

 the breadth of the body whorl, and exhibiting distinctly all the 

 votutions. Diameter three quarters of an inch. Found by Mr. 

 Lesueur near Lake Erie. 



H. LINEATA. — Shell very much depressed, somewhat discoidal. 

 TVhorls about four, each longer than broad, witb numerous raised, 

 parallel, equidistant, regular, revolving lines. Suture impressed. 

 Umbilicus very large, diameter at least equal to the breadth of 

 the body-whorl, and exhibiting all the volutions distinctly. Aper- 

 ture longer than wide, lunate. Diameter three-twentieths of an 

 inch, nearly. 



Collection of the Academy. 



Found by Mr. Robert E. Griffith, near Philadelphia. Some- 

 what resembles the last, but is more depressed, and the strito are 

 transverse, not longitudinal, as in that shell ; the cavity beneath, 

 also, though of equal proportional diameter, is not proportionally 

 deep. 



H. TiiYROiDUS. — P. 123 et seqq., October 1817. Shell thin, 

 fragile, convex, umbilicate ; whorls five, obtusely wrinkled, or 

 rather with equidistant, gradually elevated, obtuse lines ; and 

 spii'ally striate, with minute, impressed lines ; lip widely reflected, 

 white and flat before, partially concealing the umbilicus ; pillar- 

 lip furnished with a very oblique tooth. Breadth four-fifths to 

 nine-tenths of an inch. 



This species very much resembles H. albolabris of Nicholson's 

 Encyc, Amer. ed., but is umbilicated, and toothed on the pillar- 

 lip. It is much less common. This shell was indicated in the 

 American edition of the Encyclopedia, but its characters were not 

 laid down. 



