Tellina nux S.C.T. Hanley, 1844
Tellina nymphalis J.B.P.A. Lamarck, 1818
Cadella oahuana W.H. Dall, P. Bartsch& H.A. Rehder, 1938
Macoma obesa (FOSSIL) Krishtofovich, 1969 †
Psammotreta obesa (G.P. Deshayes, 1855)
Psammotreta obesa alta (T.A. Conrad, 1837)
Macoma obliqua (J. de C. Sowerby, 1817)
Tellina obliquaria G.P. Deshayes, 1855
Loxoglypta obliquilineata (T.A. Conrad, 1837)
Tellina obliquistriata G.B. II Sowerby, 1868
Tellinella oblonga (FOSSIL) (Sowerby, 1846 †)
Aenona oblonga (FOSSIL) Sobetskiy 1982 †
Hanleyanus oblongus (J.F. Gmelin, 1791)
Moerella obruta (FOSSIL) T.A. Conrad †
Cadella obtusalis (G.P. Deshayes, 1855)
Arcopagia oceani (FOSSIL) Orbigny, 1850 †
Tellina ochracea (P.P. Carpenter, 1864)
Olcesia ocoyana (FOSSIL) (T.A. Conrad, 1855 †)
Merisca ohishii (FOSSIL) Inoue & Mizuno 1969 †
Hertellina oligoscissulata (FOSSIL) (Jung 1969) †
Psammacoma olivella (FOSSIL) W.H. Dall, 1900 †
Bartrumia oneroaensis (FOSSIL) (Powell & J.A. Bartrum,1929 †)
Angulinides opalinus (J.F. Gmelin, 1791)
Eurytellina ophiaca (FOSSIL) W.P. Woodring, 1982 †
Peronaea oppenheimi (FOSSIL) Bohm & Weisfermel, 1913 †
Moerella opressa (FOSSIL) (Devjatilova, 1981 †)
Moerella optata (FOSSIL) (Devjatilova, 1981 †)
Macoma optiva (FOSSIL) (M. Yokoyama, 1923 †)
Leporimetis orbicularis (G.B. III Sowerby, 1889)
Cymatoica orientalis W.H. Dall, 1890
Linearis ornatissima (FOSSIL) Weller, 1907 †
Gastrana orstomi R. von Cosel, 1995
Tellina oryza R. von Cosel, 1995
Macoma osakaensis (FOSSIL) Krishtofovich, 1957 †
Tellina ostracea J.B.P.A. Lamarck, 1818