CLASS PELECYPODA 
21 
Leda leonina Dali, 1896. 
Plate 13, fig. 18. 
The Nautilus, 10:2. Nat. Hist. Soc. Brit. Columbia, Bull. No. 2; pi. 2, fig. 12. 
Shell rather thin, compressed, with the low beaks at the anterior third; 
base slightly arcuate, anterior end rounded, posterior dorsal slope concave, 
lunule and escutcheon narrow, elongated, strongly impressed, smooth, with 
the valve margins elevated; rostrum broadly and a little obliquely trun¬ 
cate ; sculpture of thin sharp concentric lamellae strongest on the rostrum, 
epidermis dull olive-gray, dehiscent; hinge with 22 anterior and 28 
posterior teeth, the chondrophore small, inconspicuous. Length, 25.5, 
height, 11; diameter, 5.25 mm. (Dali.) 
Type in U. S. N. M. Type locality off Sea Lion Rock, coast of 
Washington, in 477-559 fathoms. 
Range. Strait of Juan de Fuca to Latitude 36 north. 
Leda amblia Dali, 1905. 
Plate 3, fig. 8. 
The Nautilus, 18:123. 
Shell chalky under a polished dark olive-green periostracum, com¬ 
pressed, rostrate, concentrically and feebly irregularly striate, with obscure 
microscopic radial lines; lunule narrow, lanceolate; escutcheon, long, wide, 
smooth and slightly concave, the valve margins rising slightly in the 
median line; valves bluntly rounded in front, bluntly truncate behind, the 
rostrate portion not set off from the body by any constriction, and the 
radial subangular lines which bound the rostral area are feeble and 
obscure; interior whitish, with a deep subumbonal impression, a very 
shallow and obscure pallial sinus, very short siphons, 12 or 13 anterior, 
18 or 19 posterior normal hinge teeth, with a narrow backwardly oblique 
socket for the resilium. Length, 18; height, 9.5; diameter, 5.5 mm. 
Type in U. S. N. M. Type locality, Monterey Bay, California. 
Range. Monterey Bay, California. 
Leda conceptionis Dali, 1896. 
Plate 39, fig. 1. 
The Nautilus, 10, No. 1; 2. Nat. Hist. Soc. Brit. Columbia Bull. No. 2; pi. 2, fig. 1. 
Shell elongate, smooth, polished, compressed, with the beaks in the 
anterior third; base arcuate, prominent below the beaks; anterior dorsal 
slope slightly rounded, posterior slope straight, rostrum narrow, pointed, 
obliquely truncate, cardinal margin elevated between the halves of the 
narrow impressed, almost linear lunule and escutcheon; beaks very small, 
low, the prodissoconch conspicuous; hinge with 18 anterior and 33 pos¬ 
terior small and delicate teeth; the chondrophore narrow, produced pos- 
