UNIO 697 
erals long, apparently curved down in the middle; anterior 
. muscle scars impressed; posterior scars indistinct ; nacre white 
and iridescent. 
Length 70, height 25, diam. 17 mm. 
Type locality, Ogeechee Canal, Savannah, Georgia. 
Unio duttomanus Ira, Pr. Ac. N. Sci. Phila., II, 1841, p: 31; 
ise oN oc. Phila. VE, 1842. p. 236, pl. xxi, fig. so; 
Obs., III, 1842, p. 74, pl. xxu, fig. 50.—CHENU, Ill. Conch., 
1858, pl. xxxut, figs. 4, 4a, 42—Sowerry, Conch. Icon., 
XVI, 1868, pl. xci, fig. 492.—Simpson, Syn., 1900, p. 736. 
Margaron (Unio) duttenianus Lia, Syn., 1852, p. 35; 1870, 
P. 57: 
There seems to be only one specimen of this species known, 
and it is not in the Lea Collection. It is apparently close to 
folliculatus, but is more cylindrical and has white, shining 
nacre. As figured by Dr. Lea, the laterals are curved down in 
the middle. 
UNIO FOLLICULATUS Lea. 
Shell much elongated, straight or slightly arcuate, the dorsal 
and ventral lines being nearly parallel, convex or subinflated, 
subsolid, or rather thin, inequilateral, rounded in front, drawn 
out to a point or slight biangulation at or just below the me- 
dian line behind; the region of the base behind the center a 
little produced ; posterior ridge well developed, inclined to be 
somewhat double below, angled; surface with well marked, un- 
even, rather fine, concentric sculpture; epidermis tawny-green 
and faintly rayed in young shells, becoming dark brown or 
black in old ones, scarcely shining; pseudocardinals subcom- 
pressed, double in each valve, the upper one in the right valve 
small: laterals straight; muscle scars distinct; nacre whitish, 
tinged with dirty purple. 
Length 92, height 32, diam. 19 mm. 
Length 80, height 29, diam. 16 mm. 
Georgia. 
Type locality, Savannah River, Ga. 
