UNIO 615 
shells in his collection labeled Unio fraternus from the Chat- 
tahoochee River that I am inclined to believe are not that 
species. 
Unio CONGAR4US Lea. 
Shell rhomboid, subcompressed, rather thin to  subsolid, 
somewhat inequilateral ; beaks moderately full and slightly ele- 
vated ; their sculpture consisting of parallel undulations ; pos- 
terior ridge high, and angled, double below, the greatest diam- 
eter of the shell being along its line; in front of it the shell 
is wedge-shaped; basal line nearly straight; posterior end 
obliquely truncated above, somewhat biangulate below; sur- 
face with irregular growth lines, wrinkled on the dorsal slope ; 
epidermis dirty greenish-yellow or tawny, generally rayed, es- 
pecially in young shells, scarcely shining; left valve with two 
ragged, subcompressed pseudocardinals and two delicate lat- 
erals; right valve with two pseudocardinals, the upper small, 
and one lateral; beak cavities not deep; muscle scars super- 
ficial; nacre purplish, often lurid in the shell cavities 
Length 81, height 48, diam. 25 mm. 
Length 62, height 34, diam. 19 mm. 
Cape Fear River. North Carolina; south to Savannah, Ca. 
Type locality, Congaree River, S. C. 
Unio congareus Les, Tr. Am. Phil Soc., TV, 1831, p. 72, pl. 
VI, fig. 4; Obs., I, 1834, p. 82, p!. v1, fig. 4.—Conrap, Monog., 
III, 1836, p. 27, pl. x11, fig. 1—Han ey, Biv. Shells, 1843, 
p. 200, pl. xxu1, fig. 31-—CuENu, Ill. Conch.,-1858, pl. 111, 
figs. 5, 5a, 50.—Sowersy. Conch. Icon., XVI, 1867, pl. Lx, 
fig. 296.—SIMPSON, Syn., 1900, p. 709. 
Margarita (Unio) congareus Lea, Syn., 1836, p. 32; 1838, p. 
22. 
Margaron (Unio) congareus Lia, Syn., 1852, p. 33; 1870, p. 
54- 
Unio fulvus Lea, Tr. Am. Phil. Soc., V, p. 96, pl. x11, fig. 39; 
Obs., I, 1834, p. 208, pl. x1it, fig. 39.—HaANtey,. Biv. Shells, 
1843, p. 200, ol. xxi, fig. 32—-SowrRBy, Conch. Icon., 
XVI, 1858, pl. txxx1x, fig. 483. 
