PLEUROBEMA 785 
Margaron (Unio) brumbyanus Lea, Syn., 1852, p. 31; 1870, 
Pp: 49. 
Pleurobema brumbyana SiMPson, Syn., 1900. p. 760. 
Umo concolor Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 40; Jl. 
Nee Ne oC Auld. Wj. 1o02, p. 89; pl. xis, ne. 237; Obs., VIII, 
1862, p. 93, pl. x11, fig. 237.—-SowrErRBy, Conch. Icon., XVI, 
1868, pl. LXxxil, fig. 440. 
Margaron (Unio) concolor Lwa, Syn., 1870, p. 49. 
Less inflated, thinner, smoother and more strongly concen- 
trical!y sculptured than P. pinkstoni. I have given above the 
measurements of the types of Lea’s Unio concolor and brum- 
byanus. ‘The latter is a little smaller, a little more inflated and 
a trifle darker than concolor, but I believe they are both one 
species. 
PLEUROBEMA PINKSTONI (S. H. Wright). 
Shell almost regularly oval, inflated. subsolid, somewhat in- 
equilateral; beaks full, only moderately elevated; posterior 
ridge rather low, rcunded, the disk in front being much more 
inflated; surface with irregular growth lines; epidermis dark 
brownish or blackish, irregularly, concentrically wrinkled, of- 
ten showing the rest marks, dull; left valve with two triangu- 
lar, radial pseudocardinals and two delicate, slightly curved 
laterals; right valve with one pseudocardinal, sometimes with 
vestigial ones, and one lateral; muscle scars impressed; beak 
cavities not deep; nacre bluish-white, thicker in front, 1rides- 
cent behind. 
Length 58, height 35. diam. 30 mm. 
Alabama River system. 
Type locality, Tallapoosa River (not Tuscaloosa), Macon 
Co., Ala. 
Unio pinkstoni S. H. Wricu7, Nautilus, X, 1897, p. 136. 
Pleurobema pinkstoni Stmrson, Pr. Ac. N. Sci. Phila., p. 81, 
pl i, fic. 8; Sym, 1900; p. 758: 
Since writing the Synopsis I have seen additional material 
of this species and am inclined to place it near P. brumbyanum 
rather than in the troschelianum group. In fact it 1s close to 
