Cerion ritchiei (C.J. Maynard, 1894)
Cerion ritchiei gigantea (C.J. Maynard, 1894)
Cerion ritchiei grayi (C.J. Maynard, 1894)
Cerion ritchiei vannostrandi H.A. Pilsbry & E.G. Vanatta,1896
Cerion robusta C.J. Maynard, 1894
Cerion rodrigoi S.J. Gould, 1997
Cerion romanoensis C.G. Aguayo& M.I. Sánchez Roig, 1953
Strophiops rosacea C.J. Maynard & W.F. Clapp,1921
Cerion royi C.G. Aguayo & M.L. Jaume,1951
Cerion rubicundum K.T. Menke, 1829
Strophiops rubiginosa C.J. Maynard & W.F. Clapp,1921
Cerion rubra (G. Humphrey, 1787)
Cerion rude (L. Pfeiffer, 1855)
Strophiops rufimaculata C.J. Maynard, 1913
Cerion rufina (C.J. Maynard, 1913)
Cerion rufolabris H.H. Beck, 1837
Strophiops rufula C.J. Maynard, 1924
Strophiops russelli W.J. Clench, 1938
Cerion saetiae M.I. Sánchez Roig, 1948
Cerion sagraianum (L. Pfeiffer, 1847)
Cerion sainthilarius M.I. Sánchez Roig, 1951
Cerion salinaria (C.J. Maynard, 1913)
Cerion salvatori C. de la Torrein H.A. Pilsbry, 1927
Cerion sama W.J. Clench & C.G. Aguayo
Strophiops sampsoni C.J. Maynard & W.F. Clapp,1920
Cerion sanchezi W.J. Clench & C.G. Aguayo,1953
Cerion sanctacruzense C.G. Aguayo & M.L. Jaume,1951
Cerion sanctamariae C.G. Aguayo & M.L. Jaume,1951
Strophiops santesoni C.J. Maynard, 1920
Cerion sanzi Blanes in H.A. Pilsbry& E.G. Vanatta, 1898
Cerion sarcostoma H.A. Pilsbry & Vannata,1896
Cerion saugeti C.G. Aguayo & M.L. Jaume,1951
Strophiops saurodon W.H. Dall, 1905
Strophiops saxitina C.J. Maynard & W.F. Clapp,1921
Strophiops scalarinoides H.P. Plate, 1907