384 PROCEEDINGS OF THE NATIONAL MUSEUM. vor.xxm. 



Subgenus Ringicardium Fischer. (Syn. Rlngicardium Fischer, 1887; 

 -^Bucurdium Gray, 1853, ei' parte ^ not of Meg'erle, 1811; Pectunculus 

 (Adanson) Morch, 1853; not of Lamarck, 1799.) Type, Cardium 

 ringens Gmelin. 



Subgenus Cerastoderma Morch. (Syn. Cerastoderma Morch, 1853; 

 + Cardium s. s. Gray, 1851, not of Lamarck, 1799; -^ Parmcardium 

 Monterosato, 1881:.) Type, Cardium ed^de Linnaeus. 



Section Dmocardiuin Dall, 1900. Type, Cardiwn magnum. Born. 



Subgenus Ethmocardium White, 1880. Type, Cardium whitei Dall, 

 = Ca?'dium speciosum Meek and Hay den, 1857, not Cardium speciosum 

 Adams and Reeve, 1850; Cretaceous. 



Subgenus Tropidocardium Roemer. (Syn. Tropidocardium. Roemer, 

 1868; + Cardium s. s. of many authors, not of Lamarck, 1799.) Type, 

 Cardium costatum Linnaeus. 



Subgenus Fragum Bolten. (Syn. Fragum Bolten, 1798; + Isocar- 

 dia Oken, 1815, not of Lamarck, 1799; + Ilemicardium Swainson, 

 18-40; + Bucardium Gray, 1853; + Loxocardium Cossmann, 1887.) 

 Section Fragum s. s. Type, Cardium unedo Linnaeus. 

 Section HemicaTdium (Cuvier) Dall, 1900. Type, Cardium 



hemicardium Linn^us. 



Section Trigoniocardia Dall, 1900. Type, Cardium graniferum 



Sowerby. 



Section Ctenocardia H. and A. Adams, 1857. Type, Cardium 



hystrix Reeve. 



Subgenus Papyridea Swainson (Syn. Papyridea Swainson, 1810.) 

 Type, Cardium spinosum Meuschen. 



Section Fuhna Gray. (Syn. Fidvia Gray, 1853, not FuVuia H. 



and A. Adams, 1858; Fischer, 1887, etc.) Tj'^pe, Cardium apertum 



Bruguiere. 



Subgenus Laevicardium Swainson. (Syn. LcBiu.ca7'dium Swainson, 

 184:0; + Liocardium Morch, 1853.) Type, Cardium norvegicum 

 Spengler. 



Section Pachycardium Conrad, 1870. Type, Cardium spillmani 



Conrad; Cretaceous. 



Subgenus Discors Deshaj^es. (Syn. Discors Deshayes, 1858; + 

 Lyrocardium Meek, 1876; + Amphicardium von IVIartens, 1880; 

 + Divaricardium DoUfus and Dautzenberg, 1886.) Type, Cardium 

 suhdiscors d'Orbigny. 



Genus SERRIPES Beck. 



(Syn. Serripes (Beck) Gould, 1841; + Aphrodite Lea, 1834, not 

 Hiibner, 1816; + Acardo Swainson, 1840, not of Lamarck, 1799.) 

 Type, Cardium gronlandicuni Gmelin. 



