984 NODULARIA 
subcompressed, somewhat irregular; laterals delicate; ante- 
rior scars impressed; nacre silvery-white, thinner behind. 
Length 57, height 27, diam. 21 mm. 
India; Siam. 
Umio shurilefianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p- 
o4? Obsi; VI-1857,. p22) pk ey ene 7s Ae en oe 
Phila., TT, 1858;p;'302; pl. xxvii, 17; 
Margaron (Unio) shurtlefianus Lea, Syn., 1870, p. 32. 
Nodularia shurtleffiana SIMPSON, Syn., 1900, p. 813. 
A larger species than cerulea, biangulate, and not so point- 
ed behind. The color of the epidermis is different and the 
surface is sculptured to a greater extent. 
NODULARIA ANCEPS (Deshayes). 
Shell irregularly long elliptical, subsolid, convex, inequi- 
lateral; beaks neither very full or high, sculptured with fine, 
radial ridges, some of which are zigzagged and extending 
well on to the disk; the sculpture gradually changes to fine 
nodulous corrugations and fades out on the border of old 
shells: posterior ridge well developed, having a tendency to 
be narrowly double, ending behind in a point or slight bian- 
gulation at or below the median line; anterior end rounded ; 
base line straight or lightly curved, full behind the middle; 
hinge line lightly curved; dorsal slope obliquely truncated ; 
surface and epidermis roughened, scarcely shining, ashy, yel- 
lowish-green or greenish, frequently banded with yellowish 
and darker behind, where it is sometimes faintly rayed; hinge 
teeth subsolid; pseudocardinals rather short; anterior scars 
well impressed ; nacre white or flesh-colored, brilliant. 
Length 43, height 24, diam. 14 mm. 
Cambodia. 
Unio anceps Desuayes, Nouv. Arch. de Mus., X, 1874, p. 127,. 
pl. vi, figs. 8-12. 
Nodularia anceps SIMPSON, Syn., 1900, p. 814. 
Oxynaia anceps Haas, Con. Cab., Unio, 1910, pl. xiv, figs. 1-3. 
Dr. Lea has a number of specimens which he has called 
U. shurtlefhanus, which I am satisfied are not that species, but 
