Tresus capax (A.A. Gould, 1850)
Mactromeris capayana (FOSSIL) (Vokes 1939) †
Lutraria capensis L.A. Reeve, 1854
Simomactra capensis (G.B. III Sowerby, 1892)
Meropesta capillacea (L.A. Reeve, 1854)
Mactra carteri (FOSSIL) A.G. Beu, 2006 †
Mactra caspia (FOSSIL) K.E.I. von Eichwald †
Mactromeris catilliformis (T.A. Conrad, 1867)
Mulinia chilota (FOSSIL) D. Frassinetti, 1997 †
Mactra chinensis R.A. Philippi, 1846
Mactra chinensis carneopicta H.A. Pilsbry, 1904
Simomactra chionia (J.R. le B. Tomlin, 1921)
Mactra chipolana (FOSSIL) W.H. Dall, 1898 †
Maorimactra chrydaea (FOSSIL) (H.H. Suter, 1911 †)
Spisula chulgunensis (FOSSIL) (L. Krishtofovich,1947 †)
Mactra cineraria (C. Linnaeus, 1758)
Mactra clathrodon (FOSSIL) Lea, 1833 †
Mulinia cleryana (A.V.M.D. D'Orbigny,1846)
Mulinia cleryana branneri W.H. Dall, 1901
Mactrellona clisia (W.H. Dall, 1915)
Darcinia columbiana (FOSSIL) Clark & J.W. Durham,1946 †
Lutraria complanata (J.F. Gmelin, 1791)
Mactrotoma compressa (L. Spengler, 1802)
Spisula compressa (FOSSIL) (G.P. Deshayes, 1832 †)
Aliomactra compressa (FOSSIL) Stephenson 1952 †
Hemimactra confraga (FOSSIL) (T.A. Conrad, 1833 †)
Mulinia congesta (FOSSIL) (T.A. Conrad, 1833 †)
Mactra constricta (FOSSIL) Woods, 1850 †
Scalpomactra continua (FOSSIL) Finlay, 1930 †
Austromactra contortula (FOSSIL) (G.P. Deshayes, 1857 †)
Austromactra contraria (L.A. Reeve, 1854)
Oxyperas coppingeri (E.A. Smith, 1884)
Mactra cordiformis L.A. Reeve, 1854
Spisula couttsi (FOSSIL) J. Marwick, 1948 †
Spisula craspedota (FOSSIL) Gardner, 1947 †