UNIO 671 
Unio musitatis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 171; 
(iNew oci Phila, LV, 1860, p..333, pl. ni, fig. 158; Obs., 
VIII, 1860, p. 15, pl. Lm, fig. 158.—Simpson, Syn., 1900, p. 
720. 
Margaron (Unio) inusitatus Lea, Syn., 1870, p. 51. 
Unio msitatus B. H. Wricut, Check List, 1888. 
I do not know what to do with this. I have only seen the 
type, and it appears to be injured. It is shaped something like 
U. livingstonensis, but it has a higher, single posterior ridge. 
The epidermis and nacre are much brighter than they are in 
lizingstonensis. 
UNIo DIFFERTUS Lea. 
Shell irregularly rhomboid, a little higher behind, inequilat- 
eral, subsolid, its greatest diameter being at the posterior ridge ; 
beaks neither full or high, their sculpture apparently irregular 
corrugated ridges; posterior ridge high, subangulate, inclined 
to be double below, ending below the median line in a very 
faint biangulation; base line curved up a little behind, nearly 
straight the rest of its length; surface with uneven growth 
lines, nearly smooth at the middle of the disk, strongly sulcate 
in front; epidermis tawny or tawny-green, scarcely rayed, 
showing the dark, widely spaced rest marks; pseudocardinals 
subcompressed, elevated, double in each valve, the upper one 
in the right valve small; laterals high, granular; beak cavities 
impressed ; muscle scars well marked; nacre flesh-color, pur- 
plish-pink and iridescent behind. 
Length 84, height 47, diam. 30 mm. 
Savannah River, Georgia. 
Type locality, Georgia? 
Umovaunertus ies Pr Ac. N.sct iila., 11; 1872, p. 158; Jl. 
Neon. sem Eola VL 1874. py a2. pl. xiv, fis 39; ‘Obs.. 
XITI, 1874, p. 46. pl. xtv, fig. 39.—Srmpson, Syn., 1900, p. 
720. 
I cannot connect this with any other form. It is a smooth 
almost waxy, rather attractive shell, evidently of rapid growth 
as the largest specimen seen shows only two rest marks. The 
nacre is rather soft and silvery, of a decidedly rich tint behind. 
