Nerita maura C.A. Récluz, 1842
Neritina mauriciae R.P. Lesson, 1831
Clypeolum mauritii (R.P. Lesson, 1831)
Nerita maxima J.F. Gmelin, 1791
Neritina maxwellorum (FOSSIL) A.G. Beu & B.A. Marshall,2011 †
Theodoxus mayeri (FOSSIL) (C.G. Semper, 1867 †)
Tomostoma medianum (FOSSIL) A.E.M. Cossmann& G. Pissarro, 1902 †
Neritina meesi (FOSSIL) B.M. Landau, F. Da Silva& S.M. Heitz, 2016 †
Neritona melanesica (E. Riech, 1935)
Nerita melanotragus E.A. Smith, 1884
Neritina meleagris (J.B.P.A. Lamarck, 1822)
Nerita menkeana C.A. Récluz, 1842
Theodoxus meridionalis R.A. Philippi, 1836
Smaragdia merignacensis (FOSSIL) (A.E.M. Cossmann& M.A. Peyrot, 1917 †)
Neritina mesopotamica E.C. Von Martens, 1874
Theodoxus micans (FOSSIL) (Gaudry& Fischer in Gaudry, 1867 †)
Clithon michaudi (C.A. Récluz, 1841)
Neritaea michonii (J.R. Bourguignat, 1852)
Theodoxus milachevitchi A.N. Golikov& Y.I. Starobogatov, 1966
Theodoxus milessii (FOSSIL) Papp, 1979 †
Theodoxus militaris (FOSSIL) (M. von Neumayr, 1869 †)
Theodoxus miljkovici (FOSSIL) (Š. Brusina, 1902 †)
Theodoxus millepunctatus (FOSSIL) (Š. Brusina, 1902 †)
Cryptonerita minima (FOSSIL) Assmann, 1924 †
Theodoxus moeschi (FOSSIL) É.A.A. Locard, 1893 †
Theodoxus moosbrunnensis (FOSSIL) Papp, 1953 †
Theodoxus morellii (FOSSIL) (L.M.D. Bellardi& O.G. Michelotti, 1841 †)
Nerita morio (G.B. I Sowerby, 1833)
Clithon morosa J. Gassies, 1870
Clithon mortoni Symonds, 2015
Theodoxus morulus (FOSSIL) Kühn, 1963 †
Nerita munita E. Forbes, 1846
Theodoxus mutinensis (FOSSIL) C. d'Ancona, 1869 †
Nerita namnetensis (FOSSIL) Vasseur, 1881 †
Neritina natalensis L.A. Reeve, 1855