CLASS PELECYPODA 
23 
area behind; there is an obscure radial depression anteriorly, and two 
obscure radial ridges on each side of the impressed escutcheon where the 
dorsal margin of the valves is prominently elevated; there are about 12 
anterior and 18 posterior teeth, the resilifer is small, rotund, and subum- 
bonal; there is a small mesial ridge near the end of the rostrum internally. 
Length, 12; height, 5; diameter, 2.6 mm. (Dali.) 
Type in U. S. N. M., No. 208897. Type locality, Station 4367, off 
Point Loma, San Diego, California, in 215 fathoms mud. 
Range. Santa Barbara to Point Loma, California. 
Leda fiascona Dali, 1916. 
Proc. U. S. N. M., 52:397. 
Shell small, rounded, thin, dull olive, the anterior slightly shorter 
than the posterior end, the base arcuate; the posterior end attenuated, 
compressed, pointed; sculpture of fine concentric threads, close set and 
covering the anterior two-thirds of the valves, stopping abruptly at the 
posterior third where the compression begins; beaks not prominent, a 
small and narrow lunule and escutcheon indicated; hinge with eight 
anterior and about four posterior teeth, the resilifer small, subumbonal, 
not projecting. Length, 4; height, 2.7; diameter, 1.7 mm. (Dali.) 
Type in U. S. N. M., No. 215597. Type locality, Station 2923, off 
San Diego, California, in 322 fathoms mud. 
Range. Known only from the type locality. 
Leda phenaxia Dali, 1916. 
Proc. U. S. N. M., 52:397. 
Shell small, solid, plump, smooth, except for faintly evident incre¬ 
mental lines and delicate radial striulse; periostracum dark olive immedi¬ 
ately under the beaks blackish for a short distance; base evenly arcuate, 
dorsal slopes nearly straight; beaks nearer the anterior end, full not 
pointed, with a short-cordate lunular impression and narrow, elongate 
escutcheon, neither defined by any sharp boundary; hinge very strong for 
the size of the shell, with about 8 or 9 long teeth on each side of a rather 
strong resilifer. Length, 4.5; height, 3.5; diameter, 1.3 mm. (Dali.) 
Type in U. S. N. M., No. 215596. Type locality, Station 2923, off 
San Diego, in 322 fathoms mud. 
Range. Known only from the type locality. 
Leda hamata Carpenter, 1864. 
Plate 6, fig. 4, and plate 37, fig. 5. 
Suppl. Rep. Brit. Assoc., p. 98. Proc . U. S. N. M., 24; pi. 40, fig. 9. 
Shell compressed, arched, lanceolate, concentrically ridged, covered 
with a thickish epidermis; posterior side attenuated, elongated, arched, 
