Eleganuculana nyeruensis (FOSSIL) C. Chen & Yang, 1983 †
Polidevcia obesa (FOSSIL) (White, 1879 †)
Nucundata obliqua (FOSSIL) C.O. Waterhouse, 1964 †
Clidophorus obliquus (FOSSIL) C.C. Stewart, 1920 †
Nuculana obolella (FOSSIL) R. Tate, 1886 †
Clidophorus obscurus (FOSSIL) W.J. Raymond, 1905 †
Phestia obtusa (FOSSIL) Hoare & al., 1989 †
Phestioidea obtusa (FOSSIL) Pojeta & al. 1986 †
Saccella ochsneri (FOSSIL) (Anderson & Martin †)
Nuculana oculata T. Iredale, 1925
Portlandella ogasawarai (FOSSIL) (S. Uozumi, 1957 †)
Portlandella olchovica (FOSSIL) A. Petrov, 1982 †
Ledellina olivacea Z.A. Filatova& A.A. Schileyko, 1984
Saccella onairoensis (FOSSIL) (J. Marwick, 1926 †)
Calorhadia opulenta (FOSSIL) †
Nuculana orcutti (FOSSIL) R. Arnold, 1907 †
Portlandella orientalis (FOSSIL) L. Krishtofovich, 1969 †
Ledella orixa (W.H. Dall, 1927)
Nuculana ornata D'Orbigny, 1845
Ledella orstomi (R. von Cosel, 1995)
Polidevcia ovata (FOSSIL) (C.F. Laseron, 1910 †)
Praesaccella ovum (FOSSIL) (Sowerby, 1825 †)
Nuculana oxyrhyncha (FOSSIL) R.A. Philippi, 1887 †
Saccella packardi (FOSSIL) (E. Forbes, 1848 †)
Saccella pahiensis (FOSSIL) (C.A. Fleming, 1950 †)
Ledella pakaurangiensis (FOSSIL) C.R. Laws, 1941 †
Saccella pakistanica (FOSSIL) F.E. Eames, 1951 †
Ledella pala (C. Hedley, 1907)
Phestia pandoraeformis (FOSSIL) (Stevens, 1858 †)
Lamellileda parallelodonta (B. Prashad, 1932)
Acilana paramushiraensis (FOSSIL) Savizky, 1972 †
Hilgardia parkei (FOSSIL) (Anderson & G.D. Hanna,1925 †)
Jupiteria parleachi (FOSSIL) (C.R. Laws, 1939 †)
Nuculana parsimonia K.H. Barnard, 1963
Mesosaccella partimstriata (FOSSIL) (Wood 1964) †