UNIO 625 
Group of Unio liebmanni. 
Shell rather solid, inflated, ovate rhomboid or trapezoidal. 
with a well-developed posterior ridge, pointed at or near the 
base behind, but not bianguiate, nearly straight or slightly 
incurved below ; beaks full, sculpture not seen; surface smooth 
or concentrically striate ; epidermis dark, scarcely rayed ; hinge 
rather strong; pseudocardinals heavy, compressed; muscle 
scars distinct ; nacre livid to whitish. 
Animal unknown. 
Unio LiGBMANNI Philippi. 
Shell rather large, inequilateral, elongated, subelliptical to 
subrhomboid, solid, convex, with a moderately developed pos- 
terior ridge, which may be rounded or angled; beaks not 
greatly elevated, their sculpture not observed; anterior end 
rounded and angled above just in front of the lunule; dorsal 
margin curved behind the beaks, sometimes feebly biangulate 
behind; basal line very slightly rounded, the post-basal point 
but little elevated; epidermis dark brown or blackish, sub- 
shining; left valve with two ragged, subcompressed pseudo- 
cardinals, the hinder reflexed, and two laterals, the upper very 
feeble; right valve with one pseudocardinal and sometimes a 
faint one above it, with one lateral sometimes slightly doubled ; 
beak cavities shallow, showing the dorsal scars; anterior mus- 
cle scars deep and somewhat torn; nacre flesh-colored or pur- 
ple. thicker in front. 
Length 92, height 50, diam. 35 mm. 
Mexico. 
Umo hebmanni Putiripri, Zeits. fir Mal., IV, 1847, p. 96; 
Abbild. und Besch., III, 1849, p. 109, pl. vi, fig. 1—KuSTER, 
Conch. Cab. Unio, 1862, p. 281, pl. xciv, fig. 7—Simpson. 
Syn., 1900, p. 712.—von Martens, Biol. Cent. Amer., Moll., 
L900; p..500; ph XXxxKIV). figs. Tegay 10: 
Margaron (Unio) licbmanni Lra, Syn., 1870, p. 48. 
I have only seen a single specimen of this species, a fine 
shell from Passo de Orijo, Mexico, presented to the National 
