694 UNIO 
ing the truncation of the dorsal slope at an angle, posterior 
ridge full, somewhat double below, ending behind in a biangu- 
lation at and below the median line; base full behind the mid- 
dle; epidermis reddish-brown and olivaceous, smooth with un- 
equal green rays; pseudocardinals small; laterals slightly 
curved; muscle scars distinct ; nacre pale purple. 
Length 74, height 37, diam. 19 mm. 
South Georgia; Florida. 
Type locality, Savannah River, Augusta, Ga. 
Unio subinflatus Conrap, Monog., XI, 1838, p. 97, pl. Liv, fig. 
1.—SIMPSON, Syn., 1900, p. 736. 
Margaron (Unio) subinflatus Lea, Syn., 1870, p. 52. 
Shorter and apparently more solid than U. aheneus. The 
posterior truncation in this species is square while in aheneus 
it is oblique, the longer point being below. I have never seen 
specimens that I can positively refer to this species. 
UNIO AHENEUS Lea. 
Shell long rhomboid, usually a little higher behind, sub- 
solid, subcompressed, inequilateral; beaks low, compressed, 
their sculpture ridges that run parallel with the growth lines; 
posterior ridge fuli, inclined to be angled and double, ending 
behind in a biangutation near the base, the lower angle longer ; 
base line nearly straight, sometimes full behind the middle; 
surface unevenly, concentrically striate; epidermis yellowish- 
green and rayed in young shells, dark brown on old specimens. 
scarcely shining; pseudocardinals small, often strongly cross- 
striate and imperfect; laterals delicate; muscle scars shallow; 
nacre purplish or chocolate. 
Florida. 
Type locality, Black Creek, Fla. 
Unio ahencus Lea, Desc. t2 Uniones, 1843 (no paging) ; Tr. 
Am: Phil. Soc., IX, 1846, p. 280) pl cagy fe 29 Ons. IY, 
1848, p. 38, pl. xu, fig. 9—Sowersy, Conch. Icon., XVI, 
1866, pl. xxxvi, fig. 194.—Srmpson, Pr. U. S. Nat. Mus., 
XV, 1892; p. 431, pl. uxxn, fig. 6; Syn., 1900, p. 736. 
