CONCHOLOGIA’ CESTRICA. 83 
tubercles, at the outer bases of the tentacles; verge 
small, simple, lunate. 
S. altilis, Lea. 
Melania altilis, Lea, Proc. Amer. Phila. Soct., §. altitis. 
[W. G. B.] 
i 184 Fig. 176. 
Shell, smooth, sub-globose, thick, pale horn 
color; spire short; whorls 4, obtusely angular 
above; aperture large, nearly round, white. 
H. 8, W. 6, mill. 

Lingual Dentition of S. altilis, with the rachidian tooth greatly 
enlarged. — [Stimp. } 
Fig. 177. 
War 
(2 ee ey ISN : 
\/ yan \ 
ey pr 
mae 

Station, Delaware and Susquehanna Rivers; abundant. 
Family STREPOMATID. 
Shell, elongate-conical, or turbinate; peristome not 
entire. 
Animal, rostrum long; foot oval; tentacles subulate; 
eyes at their external basse: margin of the mantle not 
digitate; opercle corneous, semi-concentric, or pauci- 
spiral; oviparous, 
Genus GONIOBASIS, Lea, 1862. 
Shell, thick, elongate-conical; aperture sub-rhomboid, 
higher than wide; columella not twisted; base sub- 
angular, without a channel. 
