Theodoxus abnormis (FOSSIL) (B.W. Jenkins, 1864 †)
Theodoxus acuticarinatus (FOSSIL) (A. Fuchs, 1870 †)
Neritina adansoniana C.A. Récluz, 1841
Nerita adenensis (H.K. Mienis, 1978)
Neritina adumbrata L.A. Reeve, 1855
Nerita affinis L.A. Reeve, 1841
Nereina afra G.B. Sowerby, 1836
Nereina afra aequinoxialis P.M.A. Morelet, 1848
Theodoxus africanus (L.A. Reeve, 1856)
Theliostyla albicilla (C. Linnaeus, 1758)
Theliostyla albicilla fasciata (C.F.F. von Krauss, 1848)
Theodoxus almelae (FOSSIL) (Revilla, 1958 †)
Tomostoma altavillensis (FOSSIL) A.E.M. Cossmann & G. Pissarro †,
Tomostoma altavillensis neritoides (FOSSIL) G.P. Deshayes, 1825 †
Theodoxus altenai (H. Schütt, 1965)
Nerita alternans (FOSSIL) R. Tate, 1876 †
Fluvinerita alticola H.A. Pilsbry, 1932
Nerita alveolus J.B. Hombron& C.H. Jacquinot, 1854
Theodoxus amblygonioides (FOSSIL) W.A. Wenz, 1930 †
Theodoxus amethystinus (FOSSIL) (Š. Brusina, 1874 †)
Pseudonerita amoena (A.A. Gould, 1852)
Theodoxus anatensis G.B. Sowerby, 1849
Theodoxus anatolicus C.A. Récluz, 1841
Theodoxus anconae (FOSSIL) (G. Capellini, 1880 †)
Otostoma angistoma (FOSSIL) (G.P. Deshayes, 1825 †)
Theodoxus angularis (FOSSIL) Gozhik, 2002 †
Tomostoma angusta (FOSSIL) Symonds & J.M. Pacaud,2010 †
Theodoxus anonymus (FOSSIL) V.V. Anistratenko& Gozhik, 1995 †
Nerita antiquata C.A. Récluz, 1841
Septaria apiata (E.J. Le Guillouin C.A. Récluz, 1841)
Nerita apparata (FOSSIL) Cragin, 1893 †
Vittina aquatilis (L.A. Reeve, 1855)
Neritina arcifera O.A.L. Mörch, 1872
Nerita argus C.A. Récluz, 1841
Nerita ascensionis J.F. Gmelin, 1791