8 
posterior about 20, the resilifer minute, subumbonal, not project- 
ing, interior chalky, a small medial ridge near end of rostrum. 
Height 7, length 16, diameter 5 mm. 
21:0047 Leda amiata Dall. Off San Diego, Cal., in 488 fathoms. 
Shell light olivaceous, elongate, compressed, posterior dorsal 
margin nearly straight; beaks low, polished, about 3.5 mm from 
anterior end, showing the whitish prodissoconch; the smooth sur- 
face continues for a short distance when the sculpture changes 
to sharply evenly lamellose with slightly larger interspaces wider 
on the rostral area which is defined by the angular turn of the 
lamellae which stop short at the sharp margin of the long im- 
pressed escutcheon; interior porcellanous, with 12 anterior and 
16 posterior teeth, the resilifer minute, subumbonal, hardly pro- 
jecting. Length 11.3, height 4.5, diameter 3 mm, 
21:0048 Leda oxia Dall. Off Santa Rosa Island, Cal. (to Gulf of 
Cal.), 
Shell minute, rounded in front, very acute behind, the valve 
ending in a sharp point; base arcuate, beaks low, subcentral, 
dorsal slopes nearly straight; sculpture of regular, equal concen- 
tric ridges with subequal interspaces, a depressed ray from the 
beak to base anteriorly, a deeply impressed, concentrically striated 
escucheon bordered by a rounded keel; lunule linear; about 8 
teeth on either side of a minute resilifer. Length 4.5, height 3, 
diameter 1 mm. 
21:0049 Leda liogona Dall. Be ving Sea. 
21:0050 Leda fossa Baird, 1863 Alaska to Puget Sound. 
21:0051 Leda fossa sculpta Dall. Alaska. 
21:0052 Leda fossa vaginata Dall. Alaska, at Kasa-an Bay. 
21:00538 Leda fossa curtulosa Dall. Unalaska Harbor. Be, ring Sea. 
21:0054 Leda gomphoidea Dall, 1897. Off Tillamook, Oregon, 
786 fathoms. 
21:0055 Leda fiascona Dall. Off San Diego, Cal., in 822 fathoms. 
Shell small, subtriangular, rounded, thin, dull olive, the an- 
terior slightly shorter than the posterior end, base arcuate; pos- 
terior end attenuated, compressed, pointed; sculpture of fine con- 
centric threads, close set and covering the anterior 2-thirds of 
the valves, stopping abruptly at the posterior third where the 
compression begins; beaks not prominent, a smail and narrow 
lunule and escutcheon indicated; hinge with 8 anterior and about 
4 posterior teeth, the resilifer small, subumbonal, not projecting. 
Length 4, height 2.7, diameter 1.7 mm. 
21:0056 Leda phenaxia Dall. Off San Diego, Cal., in 822 fath- 
oms. 
Shell small, solid, plump, smooth except for faintly evident 
incremental lines and delicate radial striulae; periostracum dark 
olive, immediately 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 im- 
pression 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 small strong resi- 
lifer. Length 4.5, height 3.5, diameter 1.8 mm. 
21:0057 Leda spargana Dall. Off Pt. Loma, San Diego, Cal. 
Shell small, elongate, inequilateral, pale olivaceous, com- 
pressed; prodissoconch conspicuous, otherwise the beaks are low, 
and about 4 mm from anterior end of shell; sculpture of low con- 
