Strophocardia megastropha (Gray, 1825)
Cyclocardia mesembria (FOSSIL) J.D. Stilwell& Zinsmeister, 1992 †
Glyptoactis metaicha (FOSSIL) W.P. Woodring, 1982 †
Pleuromeris micella A.A. Olsson& J.T.L. McGinty, 1958
Cardites micellus (L. Penna-Neme, 1971)
Centrocardita millegrana (S. Nomura & N. Zinbo,1934)
Venericor mingoensis (FOSSIL) (Gardner & E. Bowles,1939 †)
Pteromeris minima (FOSSIL) (J. Marwick, 1924 †)
Milneria minima (W.H. Dall, 1871)
Pleuromeris miniscula (FOSSIL) (J.A. Bartrum & Powell,1928 †)
Bathycardita mironovi (FOSSIL) Krishtofovich, 1984 †
Baluchicardia moa (FOSSIL) (Gardner, 1935 †)
Miodomeris modica (FOSSIL) (G.P. Deshayes, 1858 †)
Cyclocardia moniliata (W.H. Dall, 1903)
Cardita monilifera (FOSSIL) F. Dujardin, 1837 †
Cyclocardia moniligena C.J.S. Hickman, 2015
Megacardita monodi (M. Nicklés, 1953)
Cyclocardia montereyana (FOSSIL) R. Arnold, 1908 †
Venericardia multicostata (FOSSIL) (J.B.P.A. Lamarck,1806 †)
Pleuromeris murdochi (FOSSIL) Powell, 1938 †
Cardita muricata Sowerby, 1832
Cardita murrayana (FOSSIL) R. Tate, 1886 †
Glyptoactis mutabilis (FOSSIL) d'Archaic & Haime, 1954 †
Cyclocardia myogadaniensis (FOSSIL) (Itoigawa †)
Venericor nanaplata (FOSSIL) (Gardner & E. Bowles,1939 †)
Ainicardita napanica (FOSSIL) (Ilyina, 1962 †)
Claibornicardia nasuta (FOSSIL) (W.H. Dall, 1903 †)
Venericardia natchitoches (FOSSIL) G.F. Harris, 1919 †
Venericor negritensis (FOSSIL) (A.A. Olsson, 1928 †)
Ludbrookia neocomiensis (FOSSIL) (d'Orbigny 1843) †
Carditamera newelli (FOSSIL) Rivera, 1957 †
Cardita nicaisei (FOSSIL) Coquand, 1862 †
Cyclocardia nipponensis M. Huber, 2010
Venericor nipponica (FOSSIL) (M. Yokoyama, 1911 †)
Cardites nitidus (L.A. Reeve, 1843)