PLEUROLEMA 795: 
ending in a blunt point at the base of the shell; anterior end 
rounded; base line nearly straight; outline of posterior slope 
obliquely truncated ; surface nearly smooth; epidermis brown- 
ish-green when young, dirty reddish-brown when old, dull 
colored; left valve with two pseudocardinals and two curved 
laterals ; right with one pseudocardinal and one, usually double, 
lateral; muscle scars shallow; beak cavities not deep; nacre 
flesh-colored or purplish, thicker in front. 
Length 38, height 22, diam. 17 mm. 
Chattahoochee River, Georgia. 
Type locality, Columbus, Ga. 
Unio ‘cee Eiri oene. IN. Och biitla., PX, 1857, p. 1705 
i Ae Ne se Phila -1V, 1850, p. 204, plo xxiv, fig. 86; 
Obs., VI, 1800, Pp: 22; pl. XxIv, fig. 86. 
Margaron (Unio) medicus Lea, Syn., 1870, p. 40. 
Pleurobema modica SiMpson, Syn., 1900, p. 762. 
Smaller than P. gibberum, more inflated and having a less 
distinctly biangulate posterior ridge. It is duller colored with- 
in and without. 
PLEUROBEMA STRIATUM (Lea). 
Shell small, subrhomboid, subcompressed or compressed, 
scarcely subsolid, inequilateral; beaks only moderately full 
and high, their sculpture a few strong irregular ridges; pos- 
terior ridge rounded or feebly biangulate, ending below the 
median line; anterior end rounded; base line curved; outline 
of dorsal slope curved, sometimes angular behind the liga- 
ment; epidermis decidedly, concentrically wrinkled, dirty 
greenish or brownish, somewhat cloth-like; left valve with two 
pseudocardinals and two laterals; right valve with one pseudo- 
cardinal and a double lateral; beak cavities and muscle scars 
shallow ; nacre dirty purplish, iridescent behind. 
Length 36, height 23, diam. 13 mm. 
Chattahoochee River, Georgia. 
Type locality, Columbus, Ga. 
Unio striatus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr. 
Asn Phil. Socy VILE, 1643) p. 203, pl.ixir) fig. 165; /Obs.,, ITT, 
1842, p. 41, pl. xu, fig. 16—CHENu, III. Conch., 1858, pl. 
SI ies TG ST: 
