CONCHOLOGIA CESTRICA. 



77 



Animal, foot large, greatly produced beyond the 

 rostrum, narrow, and rounded behind, truncated in 

 front; rostrum short; tentacles broader, and shorter, 

 than in Melantho ; the right one, in the male, only 

 one-third the length of the left ; operculum with a sub- 

 spiral nucleus. 



L. subcarinata, SAY. 



Paludina subcarinata, Say, Nich. Encyc., 3d Amer. 

 Edit, 1819. 



Shell, whorls 3 or 4, reticulated, with x - 

 striae, and wrinkles ; apex truncate, and 

 re-entering; suture deeply impressed; 

 aperture oval, more than half the length 

 of the shell ; carina, two, or three, or 

 absent ; color brownish - green ; within 

 bluish-white. H. 15, W. 9, mill. 



Station, Schuylkill River, Chester County ; abundant. 



Fig, 157, 



Lingual Dentition of L,. sub' 

 earinata. [W. G. B.J 



Fig, 158, 



Operculum of I/, sub- 

 carinata. [W . G. B.] 



Fig, 159, 



OBS. Our shell differs, somewhat, from the same 

 species found in Western waters. 



Family VALVATID^E. 



Animal of V. tricarinata, [W. G. B.] 

 Fig, 160, 



Shell, spiral, turbinate, or discoid ; peristome entire. 



