CLASS PELECYPODA 
193 
Type. Mactra solida (L.) Gray, 1847. 
Distribution. All seas, especially within the tropics. 
Subgenus Hemimactra Swainson, 1840. 
SECTION MACTROMERIS Conrad, 1868. 
Spisula alaskana Dali, 1894. 
Plate 15, fig. 12. 
Publ. Puget Sound Biol. Station, 4:59, pi. 4, fig. 4. 
Shell large, thick, somewhat compressed; the anterior side a little 
shorter, and the hinge margin is slightly concave, posterior slope convex 
and broader, the extremity slightly gaping. Base curved with the posterior 
end a little broader, beaks somewhat elevated, and behind them is an 
elevated line extending to the lower angle. Sculpture consists of irregular 
growth lines coarser toward the posterior end. Epidermis is coarse and 
wrinkled; the surface of the shell has a rugged appearance from the 
coarse growth lines, and rendered more rugged by the folds of the thick 
epidermis. Interior bluish-white. Hinge supports, strong and smoothly 
rounded, V-shaped tooth strong, with the anterior side in right valve more 
elevated than the posterior; lateral teeth short and slender. Muscular 
impressions large and pallial sinus deep and wide. Length, 135; height, 
90; diameter, 50 mm. (Oldroyd.) 
Type in U. S. N. M. Type locality, Alaska? 
Range. Arctic Ocean at Cape Lisburne, south to Bering Sea and the 
Aleutians and eastward to Puget Sound. Also North Japan, the Kurile 
Islands, and Okhotsk Sea. 
Spisula voyi Gabb, 1869. 
Plate 23, figs. 1, 2. 
Pal. Calif., 2: 24; pi. 5, fig. 41. 
Shell broad, inequilateral; beaks in advance of the middle; cardinal 
margin nearly straight and sloping; anterior end very much produced, 
rounded and narrow; posterior end obliquely truncated; base broadly and 
regularly rounded. Surface marked by numerous irregular and rather 
strong lines of growth. (Gabb.) 
This was described by Gabb as Callista voyi. 
Type in University of California collection. Type locality, Miocene or 
Pliocene, near Humboldt Bay, California. 
Range. Puget Sound and north. Fossil in the Miocene and Pliocene 
of California. 
