77 
1025 Potomides californica Haldeman. 
Balenas bay, California, to Mazatlan, Mexico. 
1026 Potamides montagnei Orbigny. 
Cedros Island, Lower California, to Chili. 
1027 Pristiphora oblonga Carpenter. 
San Diego, Cal. 
1028 Phophysaon andersoni J. G. Copper. 
British Columbia to Monterey, Cal. 
1029 Prophysaon pacificum Cockerill. 
Victoria, Vancouver Island. 
1030 Prophysaon ceruleum Cockerill. 
Washington—Oregon. 
1031 Pisidium occidentale Newcomb. 
Coast range counties, California, to latitude 23 deg. 30 min., 
Lower California. 
1032 Pisidium insigne Gabb. 
Uvas Pass, Kern county, California. 
1033 Pisidium ferrugineum Morse. 
Maine to Vancouver Island. 
1034 Pisidium compressum Prime. 
Canada to Vancouver Island—-Pennsylvania to Utah, Nevada, 
and Eastern California. 
1035 Pisidium abditum Haldeman. 
Maine to South Carolina, Canada and west to California— 
Honduras, Mexico?, Lower California. 
1036 Pisidium ultramontanum Prime. 
Vancouver Island to Mono county, California. 
1037 Psephis salmonea Carpenter. 
Catalina Island, California; 30-40 fms, 
1038 Psephis tellimyalis Carpenter. 
Farallon Islands to Lower California, on Haliotis. 
1039 Pterorhytis foliatus Gmelin. 
Sitaka to Santa Barbara—Asia. 
1040 Pterorhytis monoceros Sowerby. 
Southern California and Western Mexico. 
1041 Pterorhytis nuttalli Conrad. 
Balenas bay to San Diego. 
1042 Pterorhytis trialatus Sowerby. 
San Pedro to Lower California. 
1043 Ptychatractus occidentalis 
“Shell elongated, fusiform, rather slender, whitish, traversed 
by narrow, revolving brownish threads and much wider inter- 
vening spaces; suture distinct, spire tapering; aperture oblong 
oval, about half the length of the shell; within white, polished; 
canal short, nearly straight; columellar obliquely, not strongly 
plicated; length about three-fourths of an inch. MHabitat—near 
the Island of Attou, at the west end of the Aleutian Archipelago.” 
—Robert E. C. Stearns, Conchological memoranda No. 7 (28 Ag 
1871); Cal ac pr 5:—(7 Ap 1873) :—‘‘Habitat—near the Island 
of Nagai, one of the Shumagin Islands, where it was hooked up 
attached to a rock from a depth of 40 fathoms, by Captain Prime 
of the California Fishing Fleet; through the kindness of Mr. 
Harford to whom it was given, it is now in my cabinet.” 
1044 Rissoa zquisculpta Carpenter. . 
California to Galapagos Islands. 
1045 Rissoa castanea Moller. 
Arctic sea to North Carolina, and Vancouver Island. 
1046 Rissoa compacta Carpenter. 
Straits of Fuca. 
