UNIO 637 
right valve with one pseudocardinal, a vestigial one above it 
and ene double lateral; beak cavities shallow; muscle scars 
small, impressed; nacre dull purple. 
ength 70, height 45, diam. 27 mm. 
Type locality, St. Mary’s River, Florida. 
Unio lehmanu S. H. Wricut, Naut., X, 1897, p. 138.—SriMp- 
son, Pr. Ac. N. Sci. Phila., 1900, p. 8o, pl. Iv, fig. 9 ;—Syn., 
1900, p. 715. } 
A short, nearly elliptical, solid, convex shell, with shining 
epidermis and double laterals in the right valve. The nacre 
is dull, but slightly iridescent behind. 
UNIO RURTCHIANUS 9S. H. Wright. 
Shell long elliptical, subcompressed or convex, solid, inequi- 
lateral ; beaks apparently only moderately full or high; poster- 
ior ridge well developed, somewhat double, ending in a nar- 
row biangulation at or a little below the median line; surface 
nearly smooth; epidermis tawny, more or less rayed with 
green; in the type, a voung shell, the green color preponder- 
ates; left valve with two rather small, ragged pseudocardinals 
and two curved laterals; right valve with two pseudocardinals, 
the upper small, and one lateral, which sometimes is partially 
double; beak cavities shallow ; muscle scars small, impressed ; 
nacre copper-colored, sometimes tinted salmon. 
Length 53, height 20, diam. 16 mm. 
Length 62, height 38, diam. 20 mm. 
Type locality, St. Mary’s River, Florida. 
Unio burtchianus S. H. Wricut, Naut., X, 1897, p. 137.— 
Simpson, Pr. Ac. N. Sci. Phila., r900, p. 80, pl. iv, fig. 8 ;— 
Syn., 1900, p. 715. 
Too close to U. lehmanti. The only differences I can see are 
that this species is a little lower in proportion and less inflated 
than that species. The nacre of the three specimens | have 
seen is a little warmer in tint, but this is a character of very 
trifling value. The measurements first given are for the type, 
a young shell which shows quite green from the large num- 
