1915.] NATURAL SCIENCES OF PHILADELPHIA. 553 



This is Obovaria lens Lea (1831) of Simps. Synops., p. 600, Descr. 

 Catal., p. 293. 



Obovaria olivaria Raf. 



Amblema olivaria {U. olivaria) Raf. Monogr. (1820), p. 314, No. 53. 



The types are A. N. S. P. Coll. No. 20,251, from the Kentucky 

 River. 



Length 58, height 46, diam. 32 mm. 



Length 53, height 40, diam. 29 mm. 



This is Obovaria ellipsis Lea (1828) of Simps. Synops., p. 602, 

 Descr. Catal., p. 299. 



Plagiola lineolata Raf. 



Obliquaria depressa {U. depressa) Raf. Monogr, (1820), p. 303, No. 22, 

 PI. 81, figs. 5,. 6, 7. 



The tjT)e is A. N. S. P. Coll. No. 20,207, from the Ohio River. 

 Length 50, height 37, diam. 16 mm. 

 This is not Unio depressa Lam. (1819). 



Obliquaria lineolata {U. lineolata) Raf. Monogr. (1820), p. 303, No. 23. 



The type is A. N. S. P. Coll. No. 20,242, from the Ohio River. 

 Length 71, height 61, diam. 33 mm. 



Obliquaria ellipsaria {U. ellipsaria) Raf. Monogi'. (1820), p. 303, No. 24. 



This shell is A. N. S. P. Coll. No. 20,233, from the Ohio River. 

 Length 58.5, height 48, diam. 39.5 mm. 



These three shells are Plagiola securis Lea (1829) of Simps. Synops., 

 p. 603, Descr. Catal., p. 304. 



Plagiola elegans Lea. 



Truncilla truncata {Unio truncata) Raf. Monogr. (1820), p. 301, No. 19. 



The type is A. N. S. P. Coll. No. 20,217, from the Falls of the 

 Ohio River. 



Length 42, height 36, diam. 22.5 mm. 

 This is not Unio truncata Spengl. (1793). 



Unio metaplala (Tr. do. 1S22) Raf. Continuation of Monogr. (1831), p. 4, 

 No. 101. 



The type is A. N. S. P. Coll. No. 20,258, from the Cumberland 

 River, gift of S. S. Haldeman. 



Length 47, height 39, diam. 27 mm. 



These two shells are Plagiola elegans Lea (1831) of Simps. Synops., 

 p. 604, Descr. Catal., p. 307. 

 36 



