NODUT,ARIA IOI7 
tric sulcations, the sculpture of the posterior slope stronger, 
and curving upward; pseudocardinals of the left valve 2 to 3, 
ragged, the anterior larger, two in the right valve, with a par- 
allel sided socket, the larger teeth compressed but rather solid. 
Type, Unio crispisulcatus Benson. 
NODULARIA CRISPISULCATA (Benson). 
Shell somewhat subtriangulate, slightly inequilateral, con- 
vex to subinflated, subsolid; umbonal region high; beaks ele- 
vated but rather compressed, pointed, sculptured with numer- 
ous, distinct, radial-zigzag ridges, these ridges extending all 
over the shell and on the later growth are crossed by fine, de- 
cided, concentric sculpture causing the surface to be reticulated 
in a marked degree; along the full, rounded posterior ridge the 
sculpture is divaricate; anterior end narrowed and rounded; 
base line lightly curved, usually a little fuller behind the mid- 
dle; outline of dorsal slope curved down to the rounded or 
sometimes biangulate point; epidermis yellowish-green to 
brownish, often with lighter and darker bands, dull; hinge line 
strongly arched; pseudocardinals subcompressed, ragged ; lat- 
erals remote, rather short; muscle scars well marked; nacre 
whitish, often yellowish in the cavities. 
Length 52, height 33, diam. 21 mm. 
Length 4o, height 29, diam. 16 mm. 
Burma. 
Unio crispisulcatus BENsonN, Ann. and Mag., X, 1862, p. 193. 
—Sowersy, Conch. Icon., XVI, 1866, pl. xuix, fig. 262.— 
HANLEY and TueropaLp, Conch. Ind., 1876, p. 6, pl. x1 
fig. 5: 
Margaron (Unio) crispisulcatus Lea, Syn., 1870, p. 31. 
Nodularia crispisulcata StMPSON, Syn., 1900, p. 820. 
A large series of this form is before me. It is one of the 
few distinctly cancellated Uniones. Notwithstanding its sub- 
triangular form, it shows relationship to the other forms of 
Nodularia, especially to such species as N. occata and N. 
gratiosa. 
