IOO CONCHOLOGIA CESTRICA. 



S. rosaceum, PRIME. 



Cyclas rosaceum, Prime, Bost. Proc., IV., 1851. 



S. rosaceum, [Prime.] 

 Fig, 201, 



Shell, small, round-oval, fragile, transparent, sub- 

 equilateral ; margins generally rounded ; beaks calycu- 

 late, approximate, inclined forward ; valves very slight, 

 a little convex, fine striate ; epidermis reddish-brown, 

 shining; teeth very slight, laterals elongated. H. 4^, 

 W. 6, T. 3j, mill. 



Station, Pickering Creek, and Schuylkill River, Ches- 

 ter County ; rare. 



S. partumeium, SAY. 



Cyclas partumeium, Say, Acad. Nat. Science, Jour. 

 II., 1822. 



S. partumeium. [Prime.] ^ 



Fig, 202, 



Shell, round-oval, thin, pellucid, nearly equilateral, 

 anterior margin slightly distended; posterior rather 

 abrupt ; beaks central, calyculate, approximate ; striae 

 scarcely visible; glossy, greenish horn color; valves 

 moderately convex ; hinge margin nearly straight ; 

 cardinal teeth strong ; laterals very much elongated. 

 H. 13, W. 11, T. 8, mill. 



Station, stagnant ponds on White Clay and Pickering 

 Creeks, Chester County ; abundant. 



