64 CONCHOLOGIA CESTRICA. 



Sub-genus LIMNOPHYSA, FITZINGER, 1833. 



Shell, ovate-oblong ; whorls rounded ; spire conic, 

 about as long as the aperture ; outer lip not spreading. 



L. catascopium, SAY. 

 L. catascopium. Lymnaea catascopium, Say, Nich. Ency., 



[W.G.B.] Amer. Ed., 1817. 



Pig, 121, 



Shell, horn color, or reddish ; whorls 

 4-5, first large; the spire darker, acute; 

 aperture large, oval, less than three-fourths 

 the length of the shell. H. 18, W. 12, 

 mill. 



Lingual Dentition of L. catascopium. [W. G. B.] 

 Fig, 122, 



Station, Delaware and Schuylkill Rivers ; abundant. 



L. elodes, SAY. 



Lymneus elodes, Say, Jour. Acad. Phila. F. S., II., 

 1821. 



Shell > oblong-conic, thin; whorls 5, regularly 

 Tig, 123, rounded ; in some instances, the lines of growth, 

 with the revolving striae, produce, by their de- 

 cussation, numerous small facets ; suture mod- 

 erate ; umbilicus slight ; aperture sub-oval, less 

 than half the length, often reddish, and slightly 

 thickened, within. H. 20, W. 9, mill. 



Station, Schuylkill River ; Chester County. 

 OBS. The variable character of this species is doubt- 

 less, in a measure, due to the differences of station. 



