76 



LAND AND FRESH-WATER SHELLS OF N. A. [PART IIL 



Gillia altilis of the Santee Canal. The shell found in the 

 Delaware, and considered by Mr. Lea as Melania altilis, and 

 included by me in the preceding article as a form of Gillia 

 altilis, may prove to be a distinct species. If so, its synonymy 

 will be Leptoxis altilis, Haldeman, not Melania altilis, Lea. 



Doubtful Species of Gillia. 



Leptoxis rapacformis, of Haldeman's Monograph, probably belongs to tliis 

 genus. The species figured by him without name (pi. v, f. 157) 

 certainly does. 



SOMATOGYRUS, Gill. 



Ling.ual dentition of type : Khachidian tooth very short and 

 broad. Intermediate tooth with the body perforated. Inner and 

 outer lateral teeth with about the same number of denticles. 



Formula of the denticles; 



4-1-4 



1-14-14. Shell rather large, 



Fig. 149. 



Lingual dentition of Somatogyrus <iq9rps.S!<s.— [Stimpson.] 



globular, thin, smooth, perforate ; spire small ; suture impressed ; 

 body whirl globose, more or less shouldered above. Aperture 

 large, oblique, rhombo-ovate, narrowly rounded in front and 

 behind, with its peritreme thin and acute, and with its entire 

 margin uniformly in one plane, the outer lip not projecting 

 anteriorly. Oi)erculum rather thick, corneous, subovate ; inner 

 margin concave near the upper extremity. Foot rather short. 

 Kostrum broad. Tentacles tapering, pointed. 



Station, fresh water. 



Distribution, the central parts of North America. (Stimpson.) 



