Acrosterigma mauritiana (G.P. Deshayes, 1855) Réunion29,5 mm
Cardium maxicostatum J.J. Ter Poorten, 2007 Angola85,7 mm
Americardia media (C. Linnaeus, 1758) Florida, Miami County29,9 mm
Clinocardium meekianum (FOSSIL) (W.M. Gabb, 1866 †) USA, California80 mm
Trigoniocardia melajoensis (FOSSIL) P.O. Jung, 1969 † Dominican Republic, DajabCln
Laevicardium melvilli (FOSSIL) R.B. Newton, 1905 † Pakistan, Baluchistan, Makran
Vasticardium mendanaense (G.B. III Sowerby, 1897)
Keenocardium menneri (FOSSIL) A.I. Kafanov, 1984 † Western Kamchatka
Microcardium microtatum (FOSSIL) W.P. Woodring, 1982 † Panama, Colón
Trachycardium minbuense (FOSSIL) Noetling, 1901 † India, Meghalaya
Vasticardium mindanense (L.A. Reeve, 1844) Philippines, Palawan Island106 mm
Cardium minervae (FOSSIL) A.E.M. Cossmann& M.A. Peyrot, 1909 † France, Aquitaine13 mm
Parvicardium minimum (R.A. Philippi, 1836) Ireland4 mm
Globocardium minor (FOSSIL) Tashiro & Kozai 1988 †
Trigoniocardia minutissima (FOSSIL) F. Toula, 1911 †
Europicardium miorotundatum (FOSSIL) (F. Sacco, 1899 †)
Granocardium miyajiense (FOSSIL) Tashiro 1994 †
Pratulum modicum (FOSSIL) (J. Marwick, 1944 †) New Zealand
Agnocardia mokattamensis (FOSSIL) Abbass, 1972 †
Trachycardium mollyni (FOSSIL) E.H. Vokes, 1982 † United States, Florida, Calhoun
Hedecardium moniletectum (FOSSIL) (R. Tate, 1887 †) Australia, Western Australia, Albany
Corculum monstrosum (J.F. Gmelin, 1791) Philippines, Masbate Island45 mm
Loxocardium montense (FOSSIL) (Vincent 1930) †
Ciliatocardium moorae (FOSSIL) A.I. Kafanov, 2002 †
Cardium moricinum (FOSSIL) de Loriol, 1866 † Ethiopia, Oromia, North Shewa
Trifaricardium morrisoni J.J. Ter Poorten& M. Huber, 2007 West Australia, Rowley Shoals11 mm
Laevicardium mortoni (T.A. Conrad, 1831) Bahamas14,2 mm
Europicardium multicostatum (FOSSIL) (G.B. Brocchi, 1814 †) Italy, Piemonte70 mm
Laevicardium multilineatum W.H. Dall & W. Stimpson,1901 Venezuela44 mm
Discors multipunctatum (G.B. I Sowerby, 1833) Philippines, Siquijor36,8 mm
Trachycardium multiradiatum (FOSSIL) (Sowerby, 1846 †) Chile, Navidad Formation
Vepricardium multispinosum (Sowerby, 1838) Philippines, Masbate Island18,5 mm
Loxocardium multisquamatum (FOSSIL) (G.P. Deshayes, 1858 †) France, Aquitaine12 mm
Trachycardium multistriatum (FOSSIL) (G.B. Brocchi, 1814 †) Italy, Piemonte
Fragum mundum (L.A. Reeve, 1845) Philippines, Calituban Island31,5 mm