Strophocardia megastropha (Gray, 1825) Costa Rica, Cocos Island32 mm
Cyclocardia mesembria (FOSSIL) J.D. Stilwell& Zinsmeister, 1992 † Antarctica, Seymour Island
Glyptoactis metaicha (FOSSIL) W.P. Woodring, 1982 † Panama, Panamá, Arraiján
Pleuromeris micella A.A. Olsson& J.T.L. McGinty, 1958 Panama, Bocas del Toro5 mm
Cardites micellus (L. Penna-Neme, 1971)
Centrocardita millegrana (S. Nomura & N. Zinbo,1934) Philippines, Bohol Island26,6 mm
Venericor mingoensis (FOSSIL) (Gardner & E. Bowles,1939 †) USA, South Carolina, Georgetown
Pteromeris minima (FOSSIL) (J. Marwick, 1924 †)
Milneria minima (W.H. Dall, 1871) California7 mm
Pleuromeris miniscula (FOSSIL) (J.A. Bartrum& Powell, 1928 †)
Bathycardita mironovi (FOSSIL) Krishtofovich, 1984 † Western Kamchatka
Baluchicardia moa (FOSSIL) (Gardner, 1935 †) Texas
Miodomeris modica (FOSSIL) (G.P. Deshayes, 1858 †) France, Paris Basin
Cyclocardia moniliata (W.H. Dall, 1903) Brazil, Rio de Janeiro
Cardita monilifera (FOSSIL) F. Dujardin, 1837 † Hungary, Bakony19 mm
Cyclocardia moniligena C.J.S. Hickman, 2015
Megacardita monodi (M. Nicklés, 1953) West Sahara16 mm
Cyclocardia montereyana (FOSSIL) R. Arnold, 1908 † United States, California, Santa Cruz
Venericardia multicostata (FOSSIL) (J.B.P.A. Lamarck,1806 †) France, Paris Basin65 mm
Pleuromeris murdochi (FOSSIL) Powell, 1938 †
Cardita muricata Sowerby, 1832 Hawaii20 mm
Cardita murrayana (FOSSIL) R. Tate, 1886 †
Glyptoactis mutabilis (FOSSIL) d'Archaic & Haime, 1954 † India, Meghalaya
Cyclocardia myogadaniensis (FOSSIL) (Itoigawa †) Japan, Ishikawa21 mm
Venericor nanaplata (FOSSIL) (Gardner & E. Bowles,1939 †) USA, Mississippi, Lauderdale
Ainicardita napanica (FOSSIL) (Ilyina, 1962 †) Russia, Sakhalin
Claibornicardia nasuta (FOSSIL) (W.H. Dall, 1903 †) USA, Alabama, Covington
Venericardia natchitoches (FOSSIL) G.F. Harris, 1919 † USA, Louisiana, Natchitoches
Venericor negritensis (FOSSIL) (A.A. Olsson, 1928 †) Peru, Piura, Talara
Ludbrookia neocomiensis (FOSSIL) (d'Orbigny 1843) †
Carditamera newelli (FOSSIL) Rivera, 1957 † Peru, Ica
Cardita nicaisei (FOSSIL) Coquand, 1862 † Egypt, Sinai Peninsula
Cyclocardia nipponensis M. Huber, 2010 South Australia16,7 mm
Venericor nipponica (FOSSIL) (M. Yokoyama, 1911 †) Ajiro, Ehime, Japan
Cardites nitidus (L.A. Reeve, 1843) Japan