NORTHWEST COAST MARINE SHELLBEARING MOLLTJSKS. 39 
Superfamily CARDIACEA. 
Family CARDIIDAE. 
Genus CARDIUM Linnaeus, 1758. 
Snbgeniis Teachycardium Morcli, 1853. 
TRACHYCARDIUM QUADRAGENARIUM Conrad, 1837. 
Journ. Acad. Nat. Sci. Phila., p. 230, pi. 17, fig. 5. 
Santa Barbara, California, to Todos Santos Bay, Lower California. 
Subgenus Cerastoderma Morcb, 1853. 
CERASTODERMA CORBIS Martyn, 1784. 
Figs. Nondescript Shells, table 2, pi. 80; Univ. Cal. Zool. Publ., vol. 14, 
pi. 20, fig. 1. 
Nunivak, Pribilof, and Commander Islands, Bering Sea, south to Hakodate, 
Japan, and San Diego, California (Lower California?). 
CERASTODERMA CILIATUM Fabricius, 1780. 
Fauna Gronl., p. 410; Binney’s Gould’s Inv. Mass., p. 140, fig. 150. 
Circumboreal. Arctic Ocean and southward to Puget Sound and North 
Japan. 
CERASTODERMA DECORATUM Grewingk, 1850. 
Verb. Min. Ges. zu St. Petersburg, 1848-9, p. 274, pi. 4, figs. 3 a-g. 
Pleistocene of Alaska and British Columbia. Recent? 
CERASTODERMA CALIFORNIENSE Deshayes, 1841. (Plate 14, fig. 8.) 
Guerin, Mag. de Zool., Moll., pi. 47. 
Arctic Ocean to San Diego, California, North Japan and Okhotsk Sea. 
CERASTODERMA CALIFORNIENSE COMOXENSE Dali, 1900. 
Proc. U. S. Nat. Mus., vol. 23, No. 1214, p. 390. 
Pleistocene of Vancouver Island. Recent ? 
CERASTODERMA FUCANUM Dali, 1907. 
Nautilus, vol. 20, No. 10, p. 112. 
Southern Bering Sea, off Unimak Island, and south to Monterey, California. 
? Subgenus Ringicaedium Fischer, 1887. 
RINGICARDIUM PROCERUM Sowerby, 1833. 
Proc. Zool. Soc., p. 83 ; Conch. 111. Gardium, fig. 23. 
Pleistocene, San Diego. Cerros Island to Payta, Peru. 
Subgenus Fragum Bolten, 1798. 
FRAGUM BIANGULATUM Sowerby, 1829. 
Zool. Journ., vol. 5, pt. 4, p. 367; Conch. 111. Gardium, fig, 2. 
San Pedro, California, to Panama. 
Subgenus Trigoniocardia Dali, 1900. 
TRIGONIOCARDIA EUDOXIA Dali, 1916. 
Proc. U. S. Nat. Mus., vol. 52, p. 412. 
Catalina Island, California, to Gulf of California. 
n,H. 
