ANCYLUS DEPRESSUS, Hald. 



Plate 1.-— Fig. 2. 



A. parva, elliptica, pallida, tenui, diaphana, depressa; 

 apice obtuso. 



DESCRIPTION. 



Shell small, oval, elliptic, pale, thin in texture, 

 depressed, ends similarly curved, sides convex, 

 slope nearly rectilinear: apex obtuse, with more 

 than one-third the shell behind it. 



Dimensions. Long. 4, lat. 2.5, elev. 1.5 mil- 

 limetres. 



Geographical Distribution. Holston river, 

 in Washington county, southwestern Virginia. 



OBSERVATIONS. 



Paler, more depressed, and with a less promi- 

 nent apex than A. rivularis and tardus; posterior 

 slope less concave, than in the former; and not 

 direct, as in the latter. 



