Anachis norfolkensis K. Monsecour & D. Monsecour,2016
Strombina nuestrasenorae (FOSSIL) C.J. Maury, 1917 †
Columbellopsis nycteis (P.L. Duclos, 1846)
Mitrella nympha (L.C. Kiener, 1841)
Mitrella nympha venulata (G.B. III Sowerby, 1844)
Parvanachis obesa (C.B. Adams, 1845)
Zafra obesula (R.P.J. Hervier, 1899)
Aesopus obesus (R.B. Hinds, 1844)
Mitrella oblita (L.A. Reeve, 1830)
Pyrene obscura (G.B. II Sowerby, 1844)
Antizafra obsoleta (FOSSIL) C.A. Fleming, 1943 †
Antizafra obtusa (FOSSIL) C.A. Fleming, 1943 †
Pyrene obtusa (G.B. I Sowerby, 1832)
Pyrene obtusa lactea (L.C. Kiener, 1834)
Pyrene obtusa tankervillei R.P.J. Hervier, 1899
Suturoglypta occidualis J. Espinosa & J.A. Ortea,2013
Mitrella ocellata (J.F. Gmelin, 1791)
Pictocolumbella ocellata (J.H.F. Link, 1807)
Zafra ocellatula (R.P.J. Hervier, 1899)
Strombina ochyra (FOSSIL) W.P. Woodring, 1964 †
Lirastrombina olssoni (FOSSIL) (Perrilliat, 1972 †)
Nassarina olssoni (FOSSIL) C.J. Maury, 1917 †
Strombinella olssoni (FOSSIL) W.P. Woodring& A.A. Olsson, 1957 †
Zafra opihiensis (FOSSIL) C.R. Laws, 1933 †
Nassarina orna (FOSSIL) W.P. Woodring, 1928 †
Zafra ornata (W.H. Pease, 1868)
Columbella ortigia P.L. Duclos, 1848
Columbella ortonia P.L. Duclos, 1850
Retizafra oryza K. Monsecour & D. Monsecour,2016
Mitrella oryzoides (FOSSIL) Gardner, 1947 †
Aesopus osborni L.G. Hertlein & A.M. Strong,1951
Parvanachis ostreicola (G.B. III Sowerby, 1882)
Conella ovulata (J.B.P.A. Lamarck, 1822)
Conella ovuloides (C.B. Adams, 1850)
Anachis oxillia (P.L. Duclos, 1846)