34 XIOPLAX. 



Genus L 1 P L A X , Troschel. 

 Synonym, Haldemania, Tryon. 



1. LIOPLAX SUBCARINATA, Say. 



Haldeman, p. 8, t. 2. 



Plate 13, fig. 1. 



Haldeman's figures 1 and 2 represent the 

 full size of eastern forms of this species, but in 

 the west it attains a larger size and is more 

 ponderous ; it also differs in color, being much 

 lighter. It has not been reported south of the 

 Potomac and Ohio Rivers, but extends from 

 Pennsylvania to Iowa. 



2. LIOPL. CYCLOSTOMATIFORMIS, Lea. 



Plate 15, fig. 4. 

 Plate 13, fig. 4 (Pahdhia ElUottli, Lea). 



Cylindrically-pupseform, moderately thick, 

 surface marked by small growth lines, which 

 are flexuous; whorls 5 to 7, well rounded, 

 spire exserted, sutures deeply impressed, some- 



(60) 



