26 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
SECTION PORTLANDIA Morch, 1853. 
Leda collinsoni Dali, 1919. 
Plate 40, figs. 4, 5. 
Report Canadian Arctic Exp., 8, part A; pi. 11, figs. 3, 4. 
Shell small, inflated, slightly inequilateral, olivaceous in the young, 
tending to a dark brownish tint in the adult, the periostracum strong, 
minutely evenly vermiculately wrinkled all over; anterior end shorter, 
evenly rounded; posterior portion with a rounded ridge extending to the 
posterior extremity where it forms a rounded point, the shell being com¬ 
pressed above this ridge and the margin below slightly incurved and 
retractively obliquely truncate; the basal margin is slightly rounded; 
there is a small lanceolate impressed area in front of the low, slightly 
opisthoccelous beaks, and a large one behind them, but there is no cir- 
cumbscribed lunule or escutcheon; the interior is white, there is a large 
triangular resilifer below the beaks and eleven anterior and eight posterior 
hinge teeth; no indications of a pallial sinus appear on the specimens but 
the adductor scars are large and conspicuous. Height of specimen, 6; 
length, 8.5; diameter, 4 mm. (Dali.) 
Type in Museum at Ottawa, Nos. 4150 and 4151, type and co-type. 
Type locality, Station 27s., off Collinson Point, Alaskan Arctic, in 3 
fathoms. 
Range. Known only from the type locality. 
Leda arctica Gray, 1819. 
Plate 19, figs. 6, 6a. 
App. Parry's Voy., p. ccxli. Hanley, Mon. Nuculidce; pi. 1, fig. 5. 
Shell oval-elliptical, smooth, very slightly concentrically wrinkled; 
epidermis yellowish-green, glossy; umbones rather acute, nearly central; 
broad rounded, rather narrowed, obliquely truncated behind; inside 
glossy-white, edge plain in front. Length (from front to back), one-half 
inch; depth (from umbones to the opposite edge), one-fourth; breadth, 
one-sixth inch. (Gray.) 
Type in British Museum. Type locality, Arctic. 
Range. Collinson, Arctic Ocean and also Atlantic. 
Leda glacialis Gray, 1828. 
Reeve, Conch. Iconica, 18. Index Test. Sup pi., pi. 2, fig. 6. 
Shell oblong-subquadrate, thin, ventricose, covered with an olive or 
blackish brown epidermis; posterior side widely angular, sculptured above, 
ventral margin obliquely truncated at the end, dorsal margin slightly 
concave, depressed; umbones rounded, elevated, ventral margin rather 
