Scalpomactra scalpellum (FOSSIL) (L.A. Reeve, 1854 †)
Mactromeris sectoris (FOSSIL) Anderson & Martin, 1914 †
Hemimactra selbyensis (FOSSIL) A. Packard, 1916 †
Mactra semistriata L.A. Reeve, 1854
Spisula semisulcata (FOSSIL) (J.B.P.A. Lamarck,1805 †)
Spisula semisulcata leves (FOSSIL) A.V.M.D. D'Orbigny,1850 †
Lutraria senegalensis J.E. Gray, 1837
Tumbeziconcha senegalica (R. von Cosel, 1995)
Mactra sericea L.A. Reeve, 1854
Lutraria sieboldii L.A. Reeve, 1854
Harvella sincola (FOSSIL) A.A. Olsson, 1922 †
Meropesta sinojaponica Z. Zhuang, 1983
Cryptodon sinuosum (FOSSIL) (E. Donovan, 1801 †)
Spisula sisquocensis (FOSSIL) R. Arnold, 1907 †
Eastonia solanderi (FOSSIL) (J.E. Gray, 1837 †)
Darina solenoides (P.P. King & W.J. Broderip,1832)
Lutraria solida (FOSSIL) F.W. Hutton, 1873 †
Spisula solida (C. Linnaeus, 1758)
Hemimactra solidissima (L.W. Dillwyn, 1817)
Hemimactra solidissima similis (T. Say, 1822)
Spisula sookensis (FOSSIL) Clark & R. Arnold, 1923 †
Spisula sorachiensis (FOSSIL) S. Uozumi, 1955 †
Cymbophora species (FOSSIL) †
Scissodesma spengleri (C. Linnaeus, 1767)
Oxyperas steinmanni (FOSSIL) A.A. Olsson, 1931 †
Lutraria steynlussii M. Huber, 2010
Lutraria striata (FOSSIL) J. de C. Sowerby †
Mactrinula striatula (C. Linnaeus, 1767)
Mactra stultorum (C. Linnaeus, 1758)
Mactra stultorum lignaria T.A. de M. Monterosato
Mactrellona subalata (O.A.L. Mörch, 1860)
Avimactra subcaspia (FOSSIL) Andrussow †
Spisula subcuneata (FOSSIL) T.A. Conrad, 1838 †
Hemimactra subparilis (FOSSIL) T.A. Conrad, 1841 †
Mactrodesma subponderosa (FOSSIL) (A.V.M.D. D'Orbigny,1852 †)