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. 18 64. 



Synonymy: — Tapes 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 inequilateral, 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 pallia] 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. 183 9. — Rupellaria lamellifera Cpr. 



Farallones Islands, Cal. — Baja Cal. 



Very irregular, with obsolete radial and often very strong, 

 distant, concentric lamellae; 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.(?). 



