QUADRULA 929 
pressed in the direction of the axis of the shell; laterals granu- 
lar ; beak cavities moderately deep; one or more granular cal- 
luses behind the laterals; nacre white or lurid, slightly radially 
granular outside the pallial line. 
Animal unknown. 
QuADRULA LEAI (Gray). 
Shell somewhat lengthened, more or less obovate, convex, 
rather solid, very inequilateral ; beaks moderately full and high, 
their sculpture consisting of strong, slightly doubly-looped 
ridges, which are sharply angled behind, and radiating lire 
back of the main sculpture ; posterior ridge somewhat elevated 
above, fading out below; anterior end narrowed, rounded, 
often cut away a little below; base line curved, often quite full 
at or behind the center; outline of dorsal slope curved, some- 
times raised to an angle behind the ligament; surface more or 
less covered with strong, lachrymose pustules; these are often 
elongated, and arranged in curved or zigzagged patterns ; epi- 
dermis greenish or greenish-brown in the young shell, becom- 
ing dark brown in the adult stage, sericeous; pseudocardinals 
elongated, when adult nearly parallel with the curved, granu- 
lar laterals; beak cavities moderately deep, compressed; an- 
terior scars partly filled with rough nacre; nacre white or 
straw-colored. 
Length tot, height 62, diam. 30 mm. 
Length 88, height 47, diam. 29 mm. 
Length 75, height 52, diam. 28 mm. 
China ; ‘fonkin; Mekong River. 
Unio leai Gray, Griff. Cuvier, XII, 1834, p. 600 (index), pl. 
XxI, fig. 1—KusteR, Conch. Cab. Unio, 1861, p. 232, pl. 
LXXVIl1, fig. 3—?HeEupE, Conch. Fluv. Nank., I, 1875, pl. 
iV tie. Tes pls wh 
Quadrula leat StMpson, Syn., 1900, p. 801. 
Margarita (Unio) leati Lua, Syn., 1836, p. 17; 1838, p. 16. 
Margaron (Unio) leau Lea, Syn., 1852, p. 23; 1870, p. 34. 
Unio leeai HAN EY, Biv. Shells, 1843, p. 182, pl. xxi, fig. 55. 
Unio nodulosus Reeve, Conch. Icon., XVI, 1864, pl. 1x, fig. 32. 
