10 HELICID^. 



delicately furrowed by the striae of growth. Whorls 

 five or a little more, rounded, and separated by a well- 

 impressed suture ; base convex ; aperture rounded ; peri- 

 treme forming nearly two thirds of a circle, rather 

 broadly reflexed, white, somewhat flesh-colored behind, 

 not completely covering a small umbilical perforation. 

 The palate sometimes bears a small white tooth at the 

 middle, but oftener not. 



Diameter, three fifths of an inch ; axis, from three to 

 five tenths of an inch. 



GEOGRAPHICAL DISTRIBUTION. The Southern States, 

 from Georgia to Texas. 



REMARKS. This is a very neat shell, intermediate in 

 its size and characters between H. tliyroidus and H. 

 clausa. It is smaller than the former, and very often 

 possesses a palatal tooth much like it. It is larger and 

 darker colored than H. clausa, which never has a tooth 

 in the aperture. It varies widely hi elevation, sometimes 

 being as depressed as H. appressa, and sometimes as 

 prominent as H. elevata. Notwithstanding there is a 

 very close affinity of this shell with H. clausa , a name 

 which it has usually borne with a query, I think its 

 group of characters, with its sectional distribution, will 

 entitle it to be regarded as a true species. The figure 

 in Fe'russac, plate 50 a, fig. 7, is a good representation 

 of it. 



