150 
2179 Variety ruderata Deshayes. 1853. 
This form, which is found chiefly in the north, is character- 
ized by the turgidity and prominence of the concentric sculpture, 
which becomes more conspicuous than the radial ribs. Occasion- 
ally the shells are delicate and elegant, but usually specimens of 
this variety are rude and irregular, coarse and unattractive. 
2180 Variety orbella Cpr. 1864. 
Synonymy:—tTapes staminea tumida Cpr. (not Tapes tumida 
Sby.).—Chione Conradi Roemer. 1867. 
This form comprises individuals which have nestled in the 
borings of large Pholads, and have been obliged to grow into an 
abnormally swollen and tumid shape; usually chalky and of a 
gray tint. Abundant at Monterey, Cal. San Diego, Cal. 
2181 Variety sulculosa Dall. 1892. 
San Ignacio lagoon, Baja Cal. The concentric sculpture obso- 
lete, ribs fewer and stronger, and behind the middle of the shell 
separated by equal or even wider unsculptured channels or inter- 
spaces; color pure white. 
2182 Paphia (Callithaca) tenerrima 
Victoria, B. C.—San Quentin bay, Baja Cal. 
2183 Liocyma Beckii Dall. 1870. 
Northern Japan.—Plover bay, Siberia.—Unalaska. 
Shell subtrigonal, inflated, with yellow or greenish periostra- 
cum, and irregular concentric sulci. Length of largest individual 
18, diam. 8.5 mm. 
2184 Liocyma viridis Dall. 1871. 
Point Barrow, Arctic ocean.—Kadiak Island, Alaska.—North 
Japan. 
Shell oval, quite inzequilateral, when fresh of an olive-green 
or rich olive-brown color, bleaching on the beach to cream color, 
with regular, rather distant concentric sulci; subcompressed, 
sometimes almost rostrate behind. Max. length 38, diam. 13.5 
mm. 
2185 Liocyma Scammoni Dall. 1871. 
Port Simpson, B. C. (Scammon). 
Brown, dark, solid, with heavy hinge and strong, prominent 
ligament; umbones more central and pallial sinus more shallow 
than in other known species. Max. length 24, diam. 11.5 mm. 
2186 Venerupis lamellifera 
Synonymy:—Venus lamellifera Conr. 1837.—Petricola cor- 
dieri Desh. 1839.—Rupellaria lamellifera Cpr. 
Farallones Islands, Cal.—Baja Cal. 
Very irregular, with obsolete radial and often very strong, 
distant, concentric lamell#; under favorable conditions, especially 
in adolescent specimens, the lamellae may be thin and sharp; 
young brightly colored, adults dull and earthy, tho near its south- 
ern range it becomes more porcellanous. 
2187 Venerupis foliacea Desh. 
Cape San Lucas.—Panama. 
Synonymy:—Venus troglodytes Moerch.—Tapes squamosa 
Cpr. (the nepionic young).—Venerupis paupercula Desh.(?). 
