QUADRULA 939 
is a rudely sculptured form; the other two are smoother. 
The species is heavier than the forms I have united under 
cornuum-lune, and are rather more elongated and differently 
sculptured. 
QUADRULA CORNUUM-LUN@ (Heude). 
Shell irregularly elliptical with a tendency to become some- 
what rhomboid, subsolid to moderately solid, scarcely inflated ; 
beaks not high or full; posterior ridge low, rounded, some- 
times slightly biangulate; anterior end rounded; basal and 
dorsal lines lightly curved; posterior end somewhat obliquely 
subtruncate above, rounded or biangulate below; surface, ex- 
cept the anterior end, covered with elongated pustules, which 
are sometimes developed into radial ridges; epidermis brown 
or blackish; pseudocardinals rather small; laterals granular, 
scarcely vertically striate; beak cavities only moderately deep ; 
nacre dirty white or purplish. 
Length 52, height 38, diam. 22 mm. 
China. 
Unio montanus Heupe, Conch. Fluv. Nank., I, 1875, pl. iv. 
fig. 
Unio cornuum-lune Hrupr, Conch. Fluv. Nank., VIII, 1883, 
pl. tvil, fig. 105. 
Quadrula cornvuum-lune Simpson, Syn., 1900, p. 802. 
Unio paschalis Hrupre, Conch. Fluv. Nank., VIII, 1883, pl. 
EVV, os, 110: 
Unio verruculosus Hrunr, Conch. Fluv. Nank., VIII, 1883, pi. 
EVirE, is. TIT. 
Unio abortivus Heupvr, Conch. Fluv. Nank., VIII, 1883, pl. 
UXT, eer ne 
Unio monticcla Hrupr, Jl. de Conch., XXXII, 1884, p. 10. 
In the Synopsis the name Unio trisulcatus Heude was by 
oversight made a synonym of cornuum-line. It has a very 
different shell indeed. Heude changed the name montanus, 
proposed in 1875 for the above species, to monticola in 1884 
because the former had been used for a Unio previously. His 
name, cornuum-lune, proposed in 1883 for what I believe is 
