90 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Pandora forresterensis Willett, 1918. 
Plate 53, figs. 4, 5. 
The Nautilus, 31:134. 
Shell moderately heavy; short and deep (depth in twelve typical speci¬ 
mens averaging .67 of length). Color white, with brownish periostracum 
generally visible on both ends but most conspicuous on posterior. Left 
valve moderately convex, except for rather faint, incremental lines. Right 
valve flat or slightly convex, except near basal margin where it becomes 
abruptly concave; smooth except for several (generally 7-9) irregular, 
impressed lines running from apex to basal margin. Length, 22; height, 
15; diameter, 5; beaks, behind anterior end, 6 mm. (Willett.) 
Type in Acad. Nat. Sci. Phila. No. 118200. Paratypes are in Cal. 
Acad, of Sci. and in the Willett Collection. 
Type locality, Forrester Island, Alaska. 
Range. Known only from the type locality. 
Subgenus Heteroclidus Dali, 1915. 
Pandora punctata Conrad, 1837 (not Carpenter, 1864). 
Plate 53, figs. 6, 7. 
Jour. Acad. Nat. Sci. Phila., 7:228; pi. 17, fig. 1. 
Shell much compressed; posterior side produced, extremity rostrate, 
truncated; ligament margin recurved, sub-margin carinated; within punc¬ 
tate; cardinal teeth three in the superior valve; in the inferior, one elon¬ 
gated oblique tooth. Length, \y 2 inches. (Conrad.) 
Type in Acad. Nat. Sci. Phila. or State Museum at Albany. Type 
locality, near Santa Barbara, California. 
Range. Vancouver Island to the Gulf of California. 
Family LYONSIID7E. 
Genus LYONSIA Turton, 1822. 
Shell nearly equivalve, left valve largest, thin, subnacreous, close, trun¬ 
cated posteriorly; cartilage plates oblique, covered by an oblong ossicle; 
pallial sinus obscure, angular. Structure intermediate between Pandora 
and Anatina; outer layer composed of definite, polygonal cells. 
Type. Mya striata Montagu. 
Distribution. Greenland, North Sea, Norway, West Indies, Madeira, 
India, Borneo, Philippines, Peru, California, Oregon, Washington. Fossil 
Miocene, Pleistocene. 
Range in time. In the Miocene and Pleistocene. 
