1915.] NATURAL SCIENCES OF PHILADELPHIA. 555 
Length 46.5, height 28, diam. 8 mm. 
This is Symphynota viridis Conr. (1836) of Simps. Synops., p. 663, 
Descr. Catal., p. 484. 
Unio dilatata Raf. 
Unio dilatata (Elliptio dilatata) Raf. Monogr. (1820), p. 297, No. 11. 
The types-are A. N. 8. P. Coll. No. 20,248, from the Kentucky 
River. 
Length 76.5, height 42, diam. 24 mm. 
Another specimen, No. 20,236, 
Length 102, height 49, diam. 30 mm. 
Obliquaria sinuata (Unio sinuata) Raf. Monogr. (1820), p. 321, No. 67. 
The type is A. N.S. P. Coll. No. 20,252, from the Kentucky River. 
Length 110, height 61, diam. 37 mm. y 
These shells are Unio gibbosus Bar. (1823) of Simps. Synopsis, p. 
703, Descr. Catal., p. 597. This is not Unio gibbosus Raf. Monogr. 
(1820), p. 315, No. 56. 
Unio crassidens Lam. 
Unio nigra (Elliptio nigra) Raf. Monogr. (1820), p. 291, No. 1, Pl. 80, figs. 
123; 4: 
The type is A. N. 8. P. Coll. No. 20,243, from the Ohio River. 
Length 73, height 47, diam. 30.5 mm. 
This is Unio crassidens Lam. (1819) of Simps. Synops., p. 706, 
Descr. Catal., p. 606. 
Unio buxeus Lea. 
Unio pusilla Raf. (1820), p. 308, No. 39, is earlier than Unio 
pusillus Lea (1840), but Unio buxeuws Lea (1852) can be used for the 
species, Simps. Synops., p. 708, Descr. Catal., p. 611. 
Pleurobema clava Lam. 
Unio elliptica (Elliptio elliptica) Raf. Monogr. (1820), p. 296, No. 8. 
The type is A. N. S. P. Coll. No. 20,213. 
Length 34, height 29, diam. 29.5 mm. 
Obliquaria scalenia (U. scalenia) Raf. Monogr. (1820), p. 309, No. 42, Pl. 81, 
figs. 24, 25. 
The type is A. N. S. P. Coll. No. 20,229, from Ohio. 
Length 54, height 35, diam. 26 mm. 
Pleurobema cuneata (Unio cuneata) Raf. Monogr. (1820), p. 313, No. 52. 
The type is A. N. S. P. Coll. No. 20,228, from the Ohio River. 
Length 65, height 45, diam. 31 mm. 
These shells are all Plewrobema clava Lam. (1819) of Simps. Synops., 
745, Descr. Catal., p. 735. © 
