NODULARIA 997 
Group of Nodularia pazit. 
Shell thin, with the hinder point long drawn out, posterior 
ridge double, low, and sharp, the dorsal line above this straight 
or incurved; beak sculpture not seen; surface of the shell 
smooth, dull olive-colored; teeth exceedingly compressed ; 
pseudocardinals long, lamellar. 
NopurlARIA PAZII (Lea). 
Shell irregularly long ovate, inflated, rather thin, inequilat- 
eral; beaks full and high, with a narrow, well-marked lunule 
in front of them; posterior ridge low, very close to the dorsal 
margin, angled above, with the outline of the dorsal slope 
curved downward a little in the middle, ending about on the 
median line in a long, slightly up-curved beak; anterior end 
rounded; base lightly curved, slightly prominent behind the 
middle, behind the prominence obliquely truncated; surface 
with delicate, irregular growth lines; epidermis dirty olive 
with lighter bands, silky ; teeth lamellar, there being one greatly 
compressed pseudocardinal and two laterals in the left valve, 
and two pseudocardinais and one lateral in the right; beak 
cavities excavated ; muscle scars shallow; nacre bluish, faintly 
iridescent behind. 
Length 64, height 29, diam. 22 mm. 
China; Siam; Cambodia. 
Unio pazii Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 176; Jl. Ac. 
N. Sci. Phila., VI, 1866, p. 61; pl. xxi, fig: 60; Obs., XI, 
1867, p. 65, pl. xx1, fig. 60—Sowersy, Conch. Icon., XVI, 
1868, pl. xcrt, fig. 502. 
Margaron (Unio) pazii Lea, Syn., 1870, p. 39. 
Nodularia pazit Simpson, Syn., 1900, p. 816. 
Oxynaia pazii, Haas, Con. Cab., Unio, 1910, pl. xiv, figs. 10- 
Lic . 
A most striking and attractive species. When fresh the 
epidermis is rather dull and silky but when it is worn it be- 
comes smooth and somewhat shining and exhibits faint traces 
of rays. I know of no species in which the teeth are more 
compressed. 
