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Ostrea fisheri Dall. 
Ostrea veatchii Gabb, 1866. 
Ostrea cumingiana Dunker. 
Variety Mexicana Sby. 
Ostrea palmula Cpr. 
Ostrea serra Dall. 
Ostrea columbiensis Hanley. 
Ostrea elongata Solander. 1786. 
Ostrea chilensis Philippi. 
Ostrea multistriata Hanley. 1846. 
Ostrea tubulifera Dall. 
Ovula Vidleri Sby. 1881. 
Ovulum barbarense Dall. 
Ovulum formicarium Sowerby. 
Pachypoma inzequale Martyn. 
Pachypoma inzequale spiratum 
Pachypoma magdalena 
Pachypoma lithophorum 
Genus Paludestrina Ofb. 
Paludestrina longinqua 
Paludestrina imitator Pilsbry. 
Paludestrina Stearnsiana 
Paludestrina Hemphilli 
Paludestrina protea 
Paludestrina Seemanni 
Paludina Japonica Mart. 
Paludinella castanea Cpr. 
Paludinella newcombiana Hemphill. 
Pandora bicarinata Cpr. 
Pandora (Clidiophora) punctata Cpr 
Panomya ampla Dall. 
Panopzea generosa Gould. 
Panopea globosa Dall. 
Panopza novegica Spengler. 
Paphia grata 
Paphia staminea 
Variety petiti Desh. 1839. 
Variety laciniata Cpr. 1864. 
Variety ruderata Deshayes. 1853. 
Variety orbella Cpr. 1864. 
Variety sulculosa Dall. 1892. 
Paphia (Callithaca) tenerrima 
Paradione squalida Sby. 
Parapholas californica Conr 
Parthenia quinquecincta Cpr. 
Patula asterisca 
Patula Chiricahuana Ashmauani 
Patula horni Gabb. 
Patula idahoensis Newcomb. 
Patula pauper Gould. 
Patula solitaria Say. 
Patula striatella 
Patula strigosa Gould. 
Variety albida. Near Logan, Utah. 
Variety carnea. Near Salt Lake, Utah. 
Variety fragilis. Near Franklin, Idaho. 
Variety hybrida. Near Logan, Utah. 
Variety parma. Near Spokane Falls, Wash. 
Variety picta. Rathdrum, Idaho. 
Variety rugosa. New Brigham City, Utah. 
