956 NODUT,ARIA 
NoDULARIA TRIFORMIS (Heude). 
Shell much elongated, solid, inequilateral, subinflated ; pos- 
terior ridge raised, rounded, ending behind in a point below 
the median line; umbonal region compressed; anterior end 
rounded; base line nearly straight; slightly incurved in front 
of the middle, full behind the middle; surface with indications 
of subvertical folds; epidermis brownish; teeth much as in N. 
gladiolus, the laterals well impressed, the hinder ones elon- 
gated; pallial line with indications of a sinus behind; nacre 
whitish or bluish, dull brownish in the cavities. 
Length 70, height 20, diam. 15 mm. 
China. 
Unio triformis Hrupr, Conch. F. Nank., II, 1877, pl. xv1, fig. 
34. 
Nodularia triformis Simpson, Syn., 1900, p. 807. 
Lanceolaria triformis Haas, Con. Cab., Unio, 1910, p. 49, pl. 
3, figs. 3-5. 
Unio distortus Heupr, Conch. F. Nank., VIII, 1883, pl. ux, 
figs. 122, 122). 
Possibly only a small variety of gladiolus. ‘The shell fig- 
ured by Heude appears to turn strongly to the right at the 
posterior point and the one in the National Museum (an au- 
thor’s specimen) turns sharply to the left. The epidermis is 
rather more silky than that of gladiolus; the surface is not so 
rude. 
NopULARIA ACRORHYNCHA (von Martens). 
“Shell elongate, compressed, epidermis rather silky, black- 
ish-brown, shining, shortly rounded in front, posteriorly sculp- 
tured for the most part with subperpendicular, elongated, par- - 
allel tubercles and produced into a long, acute beak, with an 
elevated carina on the upper side extending to the extremity ; 
beaks depressed, eroded. Nacre pale reddish or yellowish-red, 
slightly showing posteriorly the external tubercles. Cardinal 
teeth of the left valve two, triangular, subequal, rugose, the 
anterior directed forward; in the right valve the anterior is 
small, compressed, nearly parallel to the dorsal margin, the 
posterior broadly triangular, rugose; lateral teeth elongate, 
