136 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
fitting into sulci of the opposite valve, one right and one left cardinal, a 
strong internal ligament; laminae absent or not distinct. 
Type. Kellia mac’andrewi Fischer. 
Distribution. Coast of Europe and Pacific coast of North America 
from the Arctic to Mexico. All the species are commensals. 
Pseudopythina rugifera Carpenter, 1864. 
Plate 15, fig. 9, and plate 38, figs. 8, 9. 
Sup pi. Rep. Brit. Assoc., p. 643. Rep. Progress Geol. Surv. Canada, 1880, p. 198, B, fig. 2. 
Shell large, thin, slightly indented; teeth minute; epidermis shaggy. 
(Carpenter.) 
Type locality, Puget Sound. Commensal with Gebia. 
Range. Known only from the type locality. 
Pseudopythina compressa Dali, 1899. 
Plate 11, fig. 11. 
Proc. U. S. N. M., 21:888; pi. 87, figs. 1, 8. 
Shell large, subquadrate, thin, moderately compressed, white, covered 
with a conspicuous, thin wrinkled, partly glossy periostracum; nearly 
equilateral, the basal margin nearly straight; beaks inconspicuous, surface 
with strong, irregular incremental lines, but no radial sculpture; pallial 
scar rather wide and irregular, merging into the subequal, rather narrow 
adductor scars; resilium large, wide, and long, more or less calcareous 
ventrally, left valve with one obscure cardinal tooth, right valve with the 
tooth better developed; the right dorsal valve margins overlap those of 
the left valve a little, but there are no distinct lamellae. Length, 18; 
height, 13; diameter, 6 mm. (Dali.) 
Type in U. S. N. M. Type locality, Bering Sea, south of Nunivak 
Island, in 4-28 fathoms. 
Range. Cape Lisburne, Arctic Ocean, to Acapulco, Mexico. Com¬ 
mensal with Crustaceans. 
Pseudopythina myaciformis Dali, 1916. 
Proc. U. S. N. M., 52:412. 
Shell small, myaciform, plum, nearly equilateral, the posterior end 
slightly shorter, wider, and rounded; anterior end more attenuated; sur¬ 
face finely concentrically threaded, but obscured by an habitual coating of 
a blackish color, probably manganese; the shell underneath it is yellowish 
white; hinge weak, the ligament carrying a long, very narrow, lithodesma. 
Length, 8.5; height, 5.5; diameter, 3 mm. (Dali.) 
Type in U. S. N. M., No. 133234. Type locality, Port Orchard, Puget 
Sound. 
Range. Puget Sound. Commensal with Crustaceans. 
