CUNEOPSIS 947 
Old specimens of this species show a little of the sudden 
swelling forward that is seen so strikingly in capitata. The 
shell is slightly inequivalve, the left valve, in the examples 
seen, being pushed down so that the right is higher. One of 
the specimens which I have examined has the posterior end 
very lightly turned to the left. 
CUNEOPSIS PIscIcuLUs (Heude). 
Shell elongated, solid, inequilateral, slightly inequivalve, 
twisted and very strongly turned to the right behind; beaks 
full, high, elongated; posterior ridge well developed, placed 
near the dorsal line, narrowly rounded, or somewhat angular 
above, ending behind in a point midway between the base and 
dorsum ; anterior end rounded; base line nearly straight; dor- 
sal outline curved a little; surface nearly smooth or with slight- 
ly elevated growth lines; epidermis greenish-brown when 
young, almost blackish when old, silky; left valve with two 
elevated pseudocardinals, the anterior somewhat spur-like, the 
hinder long triangular, with a pit between them, and two lat- 
erals, the upper small; right valve with one elevated pseudo- 
cardinal, a vestigial one behind it and a deep pit between, with 
a strong, faintly vertically striate lateral; anterior scars deep; 
posterior scars oblique; beak cavities very deep, compressed ; 
nacre white, silvery, iridescent behind ; pallial line widely trun- 
cate behind, the space outside of it radially striate. 
Length 123, height 49, diam. 30 mm. 
China. 
Unio pisciculus Heupe, Jl. de Conch., XXII, 1874, p. 115; 
Conch. Fluv. Nank., I, 1875, pl. m, figs. 6, 6a. 
Cuneopsis pisciculus SIMPSON, Syn., 1900, p. 805. 
Unio retortus von Martens, Sitz. Ber. Ges. Nat. Fr., 1875, 
p. 4; Nov. Conch., IV, 1876, p. 158, pl. cxxxv1, figs. 3, 4. 
This species is so contorted that it can scarcely be measured. 
In this character it is like Arconaia, but there is no vestige of 
an anterior wing, the pseudocardinals are constructed on a 
totally different plan and the beak cavities are deep, a char- 
acter common to all the forms I have placed in Cuneopsis, 
