686 UNIO 
Unio geminus Lea, Pr. Ac. Nat. Sci. Phila. VIII, 1856, p. 
202; Jl.“Nat. Sc. Phila 1858)sp:037 ple xehe. 45 1Obss 
VI, 1858, p. 63, pl. x, fig. 45—SIMPsoN, Syn., 1900, p. 733. 
Margaron (Umo) geminus Liza, Syn., 1870, p. 41. 
Unio satillaensis Lwa, Pr. Ac. Nat. Sci. Phila., II, 1858, p. 166; 
Ji. Ac. Nat. Scr. Phila." 1V;-1850" p= 216;- pl xxvin, tie, 90r 
Obs., VII, 1850, p. 34, pl. xxvui, fig. 96. 
Margaron (Umo) satillaensis LeA, Syn., 1870, p. 41. 
This differs from U. downiei in being less solid, in its nearly 
elliptical instead of obovate form, and in being a smoother 
shell. To the naked eye it appears as if delicately, radially 
sculptured on the disk, and under a glass it is seen that there 
are radiating rows of fine longitudinal folds of the epidermis. 
I cannot possibly separate U. satillaensis, its only difference 
consisting in a darker epidermis and slightly greater propor- 
tionate height. 
UNIO LECONTIANUS Lea. 
Shell subelliptical or subrhomboid, inflated generally solid, 
inequilateral; beaks full and apparently somewhat elevated; 
posterior ridge high, somewhat double below, ending near the 
base in a scarcely produced biangulation; base line curved or 
nearly straight; anterior end rounded; dorsal line curved; 
surface with uneven growth lines; epidermis smooth, tawny 
and raved in young shells, brownish and rayless in old ones, 
dull or subshining, showing occasional radial rows of longi- 
tudinal wrinkles; pseudocardinals strong, low, very rough, 
two in the left valve and one with sometimes a vestigial one 
above it in the right: left valve with two strong, curved lat- 
erals; right valve with one, which is inclined to be double; 
beak cavities not deep; muscle scars impressed, rather large; 
nacre dull purplish. 
Length of type, a young shell, 70, height 45, diam. 28 mm. 
Length 83, height 50, diam. 38 mm. 
Georgia. 
Type locality, Conoochee River, Ga. 
