CLASS PELECYPODA 
155 
Venus kennicottii Dali, 1871. 
Plate 14, fig. 7. 
Amer. Jour. Conch., 7:147; pi. 16, fig. 1. 
Shell cuneiform, dark ferruginous brown, ornamented with fine con¬ 
centric, slightly elevated lamellae. Valves rather inflated, thick; umbones 
prominent, rounded; within the anterior third; anterior end rounded from 
below to the lunule, which is broad, cordiform and impressed, bounded by 
a deeply incised line. Extreme anterior end of the valves rather pinched 
together. Anterior ventral margin arcuated. Posterior end thick, rather 
produced and pointed. Posterior dorsal side roundly arched from the 
umbones to the end; two obsolete carinae pass from the umbones on each 
side posteriorly, the inner pair forming the boundary of the ligamentary 
area; inner posterior and ventral margin finely crenulated. Hinge line 
strongly arched behind. Dental area broad, teeth strong. Posterior dental 
process rugose. Muscular impressions large; pallial sinus short, sharply 
angulated. Sculpture of fine concentric lamellae, slightly elevated, more 
so on the anterior end; more distant on the umbones, thickly crowded 
near the margin especially anteriorly. Lines of growth prominent at inter¬ 
vals. Lamellae passing over the ligamentary area and lunule. Interior 
white; the dark brown of the exterior may be a stain but looks natural. 
Length, 2.64; height, 2.1; diameter, 1.56 inches. (Dali.) 
Type in U. S. N. M. Type locality, Neah Bay, Washington. 
Range. Neah Bay, Washington, to Mendocino County, California. 
Genus MARCIA H. & A. Adams. 
Marcia kennerlyi (Cpr.) Reeve, 1863. 
Plate 8, fig. 4. 
Conch. Iconica, Venus, sp. 41. 
Shell oblong, somewhat square, dull opaque white, concentrically 
plicately ribbed, ribs close-set, a little recurved, rather irregular, lunule 
and ligamentary area narrow. (Reeve.) 
Type in Cuming Coll., British Museum. Type locality, Puget Sound. 
Range. Kodiak Island, Alaska, to Santa Barbara Islands, California. 
SECTION VENERELLA Cossmann, 1886. 
Marcia subdiaphana Carpenter, 1864. 
Plate 38, fig. 1, and plate 33, fig. 3. 
Brit. Assoc. Rep., 640. Proc. U. S. N. M., 14; pi. 7, figs. 5, 6. 
Hinge normal, very thin, ashy. (Carpenter.) 
Shell of medium size, oval, transverse, inequilateral, ventricose, rather 
thin; beaks small, incurved; anterior extremity quite sharply angulated 
about the middle of the shell; posterior extremity much longer and wider 
than the anterior and very evenly rounded, projecting furthest a little 
