6 PEOCEEDINGS OF THE NATIONAL MUSEUM. vol, 65 



Family CARDIIDAE. 



Genus CARDIUM Linnaeus, 1757. 



Subgenus Trachycardium Morch, 1853. 



CARDIUM QUADRAGENARIUM Conrad, 1837, valve, not reported before from the Lower 

 San Pedro. 



Living, Santa Barbara, California-Todos Santos Bay, Lower California. 

 Subgenus Cerastoderma Morch, 1853. 



CARDIUM CORBIS Martyn, 1784, quite plentiful, bnt all shells thin, fragile, broken. 



Living, Bering Sea-San Francisco, California. 



Genus PROTOCARDIA Beyrich, 1845. 



PROTOCARDIA CENTIFILOSA Carpenter, 1864, three valves. 



Living, Departure Bay, British Columbia-Lower California. 



Genus TIVELA Link, 1807. 



Subgenus Pachydesma Conrad, 1854. 



TIVELA STULTORUM Mawe, 1923. one valve. 



Living, Santa Cruz-Lower Calif orna. • 



Genus TRANSENNELLA Dall, 1883. 



TRANSENNELLA TANTILLA Gould. 1852. very plentiful. 



Living, Sitka Harbor, Alaska-Lower California. 



Genus SAXIDOiMUS Conrad, 1837. 



SAXIDOMUS NUTTALLII Conrad, 1837, not rare. 



Living, Humboldt Bay to San Diego, California. 



Genus PAPHIA Bolten, 1798. 



Subgenus Protothaca Dall, 1902. 

 Section PROTOTHACA Dall, 1902, s. s. 

 PAPHIA STAMINEA Conrad. 1837, plentiful. 



Living, Bering Sea-Lower California, 



Family PETRICOLIDAE. 

 Genus PETRICOLA Lamarck, 1801. 



PETRICOLA CARDITOIDES Conrad, 1837, plentiful. 



Living, Vancouver Island-San Pedro, California. 



Family TELLINIDAE. 

 Subgenus Moerella Fischer, 1887. 



TELLINA SALMONEA Carpenter, 1864, not plentiful. 



Living, Aleutian Islands-San Pedro, California. 



