HELIX. 



187 



preceding whorl, and turned outwards, having a sharp 

 carina on its inner edge ; the lower part is slightly 

 reflected, but attached ; lip projecting at the upper part, 

 somewhat reflected in the middle, and appressed to the 

 whorl and indented below ; pillar-lip emarginate, strongly 

 reflected, and pressed upwards into the aperture in an 

 acute angle ; aperture ear-shaped, throat very narrow, 

 with a lamellar fold or tooth within above, and another 

 more external below, with a deep sulcus between them ; 

 umbilicus open, carinated and grooved on the last whorl, 

 exhibiting nearly two volutions. 



Greatest transverse diameter more than half an inch. 



GEOGRAPHICAL DISTRIBUTION. Inhabits Georgia and 

 South Carolina, near the coast, and Florida ; common 

 near St. Augustine and at various places on St. John's 

 River ; it has also been found at Natchez. 



REMARKS. This is one of several curious species 

 which were discovered by Mr. Say in Florida, and of 

 which he formed the genus Polygyra, so called from the 

 numerous whorls of some of them. The animal does not 

 appear to differ from that of Helix ; and, as mere pecu- 

 liarities in the shell are not recognized as sufficient for 

 the subdivision of genera, his distinction has not ob- 

 tained. Mr. Say gives a separate measurement of males 

 and females, from which it would seem that he con- 

 sidered the animals to be unisexual ; a distinction which, 

 if correct, would effectually separate it from Helix, the 

 animal of which, in every case, combines both sexes in 



