Lucina orbicularis (FOSSIL) G.P. Deshayes, 1836 †
Ctena orbiculata (G. Montagu, 1808)
Ctena orbiculata filiata W.H. Dall, 1901
Ctena orbiculata recurvata W.H. Dall, 1901
Mesomiltha orbignyana (FOSSIL) (d'Archiac, 1843 †)
Divaricella ornata (FOSSIL) (A.E.R. Agassiz, 1845 †)
Divaricella ornata simillima (FOSSIL) A.E.M. Cossmann& M.A. Peyrot, 1921 †
Divaricella ornatissima (A.V.M.D. D'Orbigny,1846)
Lucina ortmanni (FOSSIL) H.F.A. von Ihering,1899 †
Lucinoma otukai (FOSSIL) K.M. Hatai & S. Nisiyama,1949 †
Fimbria ovalis (FOSSIL) Phillips, 1829 †
Tehamatea ovalis (FOSSIL) (Stanton, 1895 †)
Cryptophysema ovulum (L.A. Reeve, 1850)
Euanodontia ovum (L.A. Reeve, 1850)
Leucosphaera oyamai (T. Habe, 1962)
Eophysema ozarkana (FOSSIL) †
Phacoides pacifica (FOSSIL) A.A. Olsson, 1964 †
Pillucina pacifica E.A. Glover & D.W. Taylor,2001
Miltha packi (FOSSIL) R.E. Dickerson, 1916 †
Lucina pagana (FOSSIL) Noetling, 1901 †
Cavilucina pamela (J.C. Melvill & R. Standen,1907)
Eomiltha pandata (FOSSIL) (T.A. Conrad, 1833 †)
Miltha pandata (FOSSIL) †
Myrtea papatikiensis (FOSSIL) J. Marwick, 1926 †
Phacoides paranodonta (FOSSIL) Gardner, 1926 †
Miltha parsoni (FOSSIL) Waring, 1917 †
Lucina parva (FOSSIL) L.W. Stephenson, 1923 †
Lucina parvilineata (FOSSIL) Shumard, 1861 †
Notomyrtea paupera (R. Tate, 1892)
Codakia paytenorum (T. Iredale, 1937)
Claibornites paytensis (FOSSIL) (Woods, 1922 †)
Lucina pecten (FOSSIL) J.B.P.A. Lamarck, 1818 †
Phacoides pectinatus (J.F. Gmelin, 1791)
Parvilucina pectinella (C.B. Adams, 1852)
Lucina pensylvanica (C. Linnaeus, 1758)