CLASS PELECYPODA 
19 
striations upon the strongly impressed escutcheon; teeth much crowded, 
about 12 posterior, and about the same number in front of the minute 
subumbonal resilifer. Length, 9; height, 5.3; diameter, 3.3 mm. (Dali.) 
Type in U. S. N. M., No. 214098. Type locality, Station 3604, 
Bering Sea, in 1401 fathoms mud. 
Range. Known only from the type locality. 
Leda pernula Muller, 1779. 
Plate 19, figs. 7, 7a. 
Beschaft. Ges. Naturf. Freunde zu Berlin, 4:55, Hanley, Mon. Nuculida* pi. 3, 
figs. 56, 58. 
Shell oblong, rostrate, thick, olivaceous, sculptured with numerous 
raised concentric striae, more dense in the middle and slightly interrupted 
anteriorly; posterior side rostrated with a slight curve, depressed area 
circumscribed, inflated in the middle, apex obtuse; posterior side rather 
short, with an obscure ray, subacuminately rounded. Length, 17; height, 
10; diameter, 5.5 mm. of a specimen from Etah, Greenland. (Conch. 
Iconica.) 
Type in Berlin or Museum Sowerby. Type locality, North Sea. 
Range. Arctic Ocean to Plover Bay. Also Atlantic. 
Leda fossa Baird, 1863. 
Plate 5, fig. 6. 
Proc. Zool Soc., p. 71, 1863. Nat. Hist. Soc. Brit. Col. Bull. No. 2; pi. 2, figs. 3, 13. 
Shell small, elongate, convex, thin, umbones anterior, turning slightly 
toward the posterior end, which is elongated, narrow and truncated; 
anterior end short and evenly rounded, sculpture nearly obsolete, a few 
concentric lines discernible; escutcheon long, smooth and deep-set; an 
elongate process on the middle of interior of posterior end; hinge with a 
small internal cartilage-pit, and numerous teeth on each side. Length, 11; 
height, 6; diameter, 3.8 mm. (Baird). 
Type. Location unknown to the writer. Type locality, Vancouver 
Island, British Columbia. 
Range. Kotzebue Sound, Alaska, to Puget Sound. In the Pleisto¬ 
cene of California. 
Leda fossa sculpta Dali, 1916. 
Proc. U. S. N. M., 52:396. 
This form has regular concentric ripples on the beaks, behind a faint 
depressed ray near the anterior end and on the keels on either side of the 
escutcheon. ( Dali.) 
Type in U. S. N. M., No. 107688. Type locality, Station 2855, 
southeast of Alaska Peninsula, in 60 fathoms mud. 
Range. South of Alaska Peninsula. 
