180 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Semele rupicola Dali, 1915. 
Plate 11, figs. 9, 10. 
Proc. Acad. Nat. Sci. Phila., p. 26. 
Shell of medium size, thick, with numerous concentric growth lines, 
giving the exterior of the shell a rough appearance. Beaks slightly ele¬ 
vated. Interior stained a bright color around the edge. Pallial sinus deep. 
Length, 40 mm. 
This is Semele rupium of California authors, following Carpenter; 
not Sowerby, 1832. 
Type locality, Santa Cruz. 
Range. Santa Cruz, California, to the Gulf of California. 
Semele rubropicta Dali, 1871. 
Plate 43, fig. 10. 
Amer. Jour. Conch., 7 :144; pi. 14, fig. 10. 
Shell usually pure white, and brilliantly polished within, but occa¬ 
sionally with a faint yellowish or pinkish flush when very deeply colored 
externally. Inner margin, except on the hinge line, always pure white. 
Outside, covered with a thin yellowish green or olive epidermis usually 
wanting, color yellowish white, with rose-pink and pure white rays, color 
stronger on the lines of growth. Sculpture consisting of incised lines 
radiating from the umbones where they become obsolete; crossed by 
rounded, smooth, concentric ridges rather sharply defined by concentric 
grooves. These ridges are usually regular but sometimes bifurcating. In 
perfect specimens the radiating lines and grooves are so sharp that their 
intersections appear as if punctured. Ligament pit deep and excavated, 
cardinal and lateral teeth moderate. Anterior end much produced, rounded, 
margin rounded below, posterior end very short, almost truncated; shell 
rather inflated. Lunule deeply impressed, narrow, lanceolate, short. Gen¬ 
eral form subquadrate. Umbones inconspicuous, usually tinged with yel¬ 
low. Hinge line below the lunule with a purple spot. Interior marked with 
extremely faint radiating lines. Posterior portion of the inferior margin 
produced. Shell thick and solid. Length, 1.35; height, 1.55; diameter, .7 
inches. (Dali.) 
Type in U. S. N. M. Type locality, Beach at Soquel, Monterey Bay, 
California. 
Range. Forrester Island, Alaska, to Tia Juana, Lower California. 
Semele pacifica Dali, 1915. 
Plate 3, fig. 5. 
Acad. Nat. Sci. Phila., 1915, p. 27. 
This is the shell usually referred to 5*. cancellata Sowerby, 1830 (S. 
bellestriata Conrad, 1837), but which differs from that Atlantic species in 
