Theodoxus serratiliniformis (FOSSIL) D. Geyer, 1914 †
Theodoxus serrulatus (FOSSIL) (Š. Brusina, 1892 †)
Argonerita signata (J.B.P.A. Lamarck, 1822)
Argonerita signata reticulata (D.L.G. Karsten, 1789)
Neripteron simoni (B. Prashad, 1921)
Neritodryas simplex M.M. Schepman, 1919
Theodoxus simplex (FOSSIL) (A. Fuchs, 1877 †)
Theodoxus sinjanus (FOSSIL) (Š. Brusina, 1876 †)
Neripteron siquijorensis (C.A. Récluz, 1843)
Theodoxus slavonicus (FOSSIL) (Š. Brusina, 1878 †)
Neritina smithi J.E. Gray
Vitta sobrina (C.A. Récluz, 1845)
Theodoxus sobrinus (FOSSIL) A.E.J. Férussac, 1823 †
Theodoxus soceni (FOSSIL) E. Jekelius, 1944 †
Ninnia sokolovi (FOSSIL) N.I. Andrusov, 1909 †
Clithon solitarius Unknown Author
Vittina solium (C.A. Récluz, 1846)
Theodoxus sophievkaensis (FOSSIL) Gozhik in Gozhik& Datsenko, 2007 †
Clithon souleyetanus C.A. Récluz, 1842
Smaragdia souverbiana (R.P. Montrouzier, 1863)
Clithon sowerbianus C.A. Récluz, 1842
Neritina sparsilineata (FOSSIL) W.H. Dall, 1913 †
Neritina sphaerica (FOSSIL) A.A. Olsson & A. Harbison,1953 †
Theodoxus sphaeroidalis (FOSSIL) (Revilla, 1958 †)
Clithon spiniferus (C.A. Récluz, 1842)
Clithon spinosum (G.B. I Sowerby, 1825)
Neripteron spirale (L.A. Reeve, 1856)
Theodoxus spratti (FOSSIL) (B.W. Jenkins, 1864 †)
Neritina squamaepicta (C.A. Récluz, 1843)
Neritina squamipicta (C.A. Récluz, 1843)
Clithon squamosus Unknown Author
Nerita squamulata E.J. Le Guillou, 1841
Neritina squamulifera (FOSSIL) C.L.F. von Sandberger,1875 †
Clithon squarrosum (C.A. Récluz, 1842)
Theodoxus stanae (FOSSIL) (Š. Brusina, 1893 †)