Theodoxus leobersdorfensis (FOSSIL) (Handmann, 1887 †)
Theodoxus licherdopoli (FOSSIL) (Stefanescu, 1896 †)
Septaria lineata (J.B.P.A. Lamarck, 1816)
Theodoxus lineatus (FOSSIL) (Sinzov, 1896 †)
Nerita lirellata (H.A. Rehder, 1980)
Nerita listrota (FOSSIL) W.P. Woodring, 1973 †
Nerita litterata J.F. Gmelin, 1791
Theodoxus lituratus K.E.I. von Eichwald, 1838
Septaria livida (L.A. Reeve, 1856)
Nerita longii C.A. Récluz, 1842
Theodoxus longispina C.A. Récluz
Theodoxus lorkovici (FOSSIL) (Š. Brusina, 1878 †)
Clithon luctuosus (C.A. Récluz, 1841)
Theodoxus luteofasciatus (K. Miller, 1879)
Nerita luteonigra (H. Dekker, 2000)
Theodoxus lutetianus (FOSSIL) Monfort, 1810 †
Septaria luzonica (C.A. Récluz, 1841)
Theodoxus macedonicus (FOSSIL) W.A. Wenz, 1943 †
Neritina macgillivrayi L.A. Reeve, 1855
Theodoxus macri (G.B. Sowerby, 1849)
Septaria macrocephala E.J. Le Guillou, 1841
Theodoxus maculosus (FOSSIL) Gozhik in Gozhik& Datsenko, 2007 †
Clithon madecassinus (P.M.A. Morelet, 1860)
Nerita magdalenae J.F. Gmelin, 1791
Ninnia magna (FOSSIL) N.I. Andrusov, 1909 †
Trochonerita mammaeformis (FOSSIL) Renaux in A.E.M. Cossmann,1907 †
Semineritina mammaria (FOSSIL) (J.B.P.A. Lamarck,1804 †)
Nerita marcouana (FOSSIL) Cragin, 1895 †
Theodoxus maresi (J.R. Bourguignat, 1864)
Neritina mariae (FOSSIL) Handmann, 1887 †
Nerita marinduquenensis Vallejo, 2000
Theodoxus marteli (P.M. Pallary, 1920)
Theodoxus marteli nigra (P.M. Pallary, 1918)
Ninnia martensi (FOSSIL) (Š. Brusina, 1884 †)
Neritina martini (FOSSIL) R.E. Dickerson, 1915 †