20 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Leda fossa vaginata Dali, 1916. 
Proc. U. S. N. M. f 52:396. 
This differs from the last in having the concentric sculpture finer and 
less evident, and spread over the entire shell. (Dali.) 
Type in U. S. N. M., No. 226072. Type locality, Station 4244, at 
Kana-an Bay, Alaska, in 50 fathoms mud. 
Range. Known only from the type locality. 
Leda fossa curtulosa Dali, 1916. 
Proc. U. S. N. M., 52:396. 
Shell resembling variety sculpta, but relatively shorter than that of 
the typical form. (Dali.) 
Iype in U. S. N. M., No. 33771. Type locality, Unalaska Harbor, 
in 60 fathoms on ridge. 
Range. Bering Sea and Unalaska. 
Leda pontonia Dali, 1889. 
Plate 1, figs. 4, 5. 
Proc. U. S. N. M„ 12:257; pi. 13, fig. 5b. 
Shell stout, strong, inflated, with a thin ochre-yellow or pale olive 
epidermis and recurved, pointed, posterior end; beaks approximate, full, 
incurved, not high, slightly anterior; anterior end evenly rounded, pro¬ 
duced ; posterior end vertically compressed, produced, recurved, pointed 
but not rostrate; base evenly arcuate; radiating sculpture of occasional 
faint miscroscopic striations near the ends of the shell, usually absent, and 
a marked but not sharp-edged ridge in each valve, extending from the 
beak to the posterior point and bounding the posterior dorsal area in each 
valve; concentric sculpture of numerous fine regular continuous rounded 
threads, separated by narrower grooves; this sculpture, however, becomes 
suddenly obsolete on the cheeks of the valves and in front of the ridges, 
but fades out in a central cordate area which, though not impressed, may 
be taken to represent the escutcheon; there is no obvious lunule; interior 
polished, muscular and pallial scars faint, the former small; pallial sinus 
shallow, small, and terminal; teeth V-shaped, anterior 16, posterior 13, all 
developed; fossette internal, deep-set, subtriangular, short. Length, 14.5; 
height, 10; diameter, 6.8 mm. (Dali.) 
Type in U. S. N. M. Type locality, Stations 2807 and 2808, in 812 
and 634 fathoms, near the Galapagos Islands. 
Range. Santa Barbara Islands, California, to Peru and the Gala¬ 
pagos Islands. 
