390 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xx.u. 



There are 7 ribs on the posterior area while the rest of the shell 

 has from 13 to 18. 



Cardium (Cerastoderma) corbis Martyii, 1781. 



Haiiue: Pribilof Islands, Bering Sea, and the Aleutian chain, and 

 southward to San Diego, California, and Hakodadi, Japan. 



This is Cardium nuttallu Conrad, I'S'd'S; -{- CardiiiDi californkmuni 

 Conrad {testa juv.), 1838; + Cardium nidtaUianum, Carpenter, 1861. 



This fine shell normally has thickened loops thrown upward o\er 

 the backs of the ribs as its proper sculpture, but in some 3'oung- shells 

 the bight of the loops becomes obsolete, giving an ornament nearly 

 of the type of some species of Traclnjcardiuiii. 



Cardium (Cerastoderma) californiense Deshayes, 1839. 



Range: Bering Strait southward to Oregon, and Monterey. Cali- 

 fornia, and to Hakodadi, Japan. 



This is Cardium jj^eudofoasile Reeve. 1811. and Cardiurn hhnidiui, 

 Gould {testa juv.), 1850. 



A variety eomoxeiise Dall occurs in the bowlder clay of Vancouver 

 Island with the ribs depressed and flattened to such an extent as to be 

 defined only by the interstitial lines. 



Cardium (Cerastoderma) ciliatum O. Fabricius, 1780. 



Range: Arctic and boreal seas, southward to Puget Sound and 

 Japan. 



For synonj^my see iinder the head of this species in the East Amer- 

 ican list. The same varieties occur on ))oth coasts. 



Cardium (Cerastoderma) decoratum Grewingk. 1S50. 



Range: Bowlder clays of Alaska and British Columbia. 

 This species may very likely be found alive hereafter. 



Cardium (Fragum) magnificum (Deshayes MS.) in Carpenter, ]857. 



Range: Lower California south to Payta, Peru, in 10 to 13 tVthoms. 



This is Cardiuin, planlcostatujii Sowerb3% 1833, not of Sedgwick and 

 Murchison, 1829. Carpenter wrongl}^ refers Deshayes's name to Car- 

 dium, medium as a synonym, but the species is amply distinct from 

 Cardium medium and represents it on the Pacific coast. 



Cardium (Fragum) biangulatum Sow^erbj', 1829. 



Range: Catalina Island, California, south to Panama. 

 Cardium (Trigoniocardia) graniferum Broderip and Sowerby, 1829. 



Range: Gulf of California to Panama. 



Cardium (Trigoniocardia) alabastrum Carpenter, 1857. 

 Range: Gulf of California, 8 to 21 fathoms; Mazatlan. 



Cardium (Trigoniocardia) ovuloide Reeve, 1815. 

 Range: West coast of middle America? 



Cardium (Trigoniocardia) obovale Sowerby, 1833. 



Range: Margarita Bay, Lower California, to Ecuador. 



