62 



POLYGYRIDAE 



POLYGYRA LEPORINA Gould 



Sometimes known as Lobosciilum leporinum, Polygyra lepo- 

 rina has a shell measuring about one-fourth inch (5-6 mm.) 

 in diameter. It is easily recognized by its small size, small 

 umbilicus, hirsute surface and two 

 denticles on the peristome, which pro- 

 duce a U-shaped notch in the lower 

 part of the lip. The brownish shell 

 has a long, slightly curved plait on 

 the parietal wall. The hirsute surface 

 may be seen only in unworn speci- 

 mens. 



The only Illinois snail that might 

 be confused with this species is Pol- 

 ygyra hirsuta, but hirsuta lacks the 

 two denticles on the peristome and 

 it has a parietal plait that is different. 

 Polygyra lepor'tna is found in Illi- 

 nois only in the southern half and, with 

 the exception of one record from Clark County, it has been 

 found only in the counties of Randolph, Perry, Jackson, Union, 

 Saline and Hardin. 



Kentucky, Tennessee, Missouri, Oklahoma and Texas are 

 other states in which leporina is found. 



This snail occurs in woodlands of oak, hickory, elm, iron- 

 w^ood and hawthorn, usually about midway between top and base 

 of hills. It may be found under debris, on flat-topped rocks, 

 under limestone outcrops and among leaves. In Clark County 

 it has been found in the bottom lands of the Wabash River; in 

 Randolph County on the Mississippi bluff near Chester, the only 

 locality in which it has been observed in the valleys of the great 

 Illinois river systems. This species appears to be a migrant from 

 Kentucky or Missouri, in both of which states it is abundant. 



The genus Loboscultim was instituted in 1930 by Dr. Henry 

 A. Pilsbry to contain certain small Polygyra-\\\it snails which 

 differ from the true Polygyra in details of anatomy. The species 

 previously known as Polygyra pustula (Ferussac) was made the 

 type of the new genus Lobosculum. The snail described here is 

 the only Illinois species which may possibly be referable to this 

 new genus. 



