100 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the whole shell is more attenuated backward; there is not so much dis¬ 
tinction between the disk and the rostrum; the impressed area, along- the 
dorsal margin, is smaller and is not amphidetic, but ceases to be defined 
in front of the beaks; the radial major threads appear stronger and less 
numerous; the chondrophore or fossette is much less conspicuous and is 
formed by a small pit in the cavity under and almost behind the hinge 
margin, while in C. pseustes it is a comparatively large vertically project¬ 
ing spoon-shaped process; the general form of C. planetica is more elon¬ 
gate and the anterior patulous extension is directed forward rather than 
obliquely downward; lastly C. planetica is uniformly smaller. Length 
of shell, 24; of posterior part behind the beaks, 13; height, 14; diameter, 
11 mm. (Dali.) 
Type in U. S. N. M., No. 110720. Type locality, U. S. S. Albatross 
Station 2985, off San Diego, California. 
Range. Pribilof Islands, Bering Sea, to the Coronado Islands, Lower 
California. 
Cuspidaria beringensis Leche, 1883. 
Plate 13, figs. 4, 5. 
Vega Exp. Vet. Arb. f 3:438; pi. 32, figs. 1, 2. 
Testa valde inflata; umbonibus fere medianis; rostro sursum cavato, 
margine ventrali arcuato, sub rostro sinuato; in media testa costis radian- 
tibus cum striis alternantibus epidermide fulva. Long., 29; alt., 20; 
crass., 16.5 mm. (Leche.) 
Type in Stockholm. Type locality, Bering Sea? 
Range. Bering Sea to Panama Bay. 
Cuspidaria balboas Dali, 1916. 
Proc. U. S. N. M., 52:407. 
Shell small, whitish with a yellowish periostracum; inequilateral, 
rostrate, somewhat inflated, posterior end shorter, anterior ovately 
rounded; beaks small, pointed, not elevated; sculpture of anterior half of 
the disk faintly irregularly concentrically rippled; behind this 12-15 radial, 
more or less alternated threads extending to the margin from the umbos 
and increasing in strength backward; behind the last and strongest an 
excavated concentrically striated space marks the beginning of the rostrum 
which beyond that has four or five faint radial threads and is abruptly 
truncate. Length, 8.9; height, 5; diameter, 3.2 mm. (Dali.) 
Type in U. S. N. M., No. 208650. Type locality, Station 2911, on 
the edge of Cortez Bank. 
Range. Known only from the type locality. 
