- olkhonica, Pseudomegalovalvata olkhonica (J. Beckmann & Y.I. Starobogatov, 1975) - (VALVATIDAE)
- olla, Acleistoceras olla (Saemann †) - (ACLEISTOCERATIDAE) (FOSSIL)
- olla, Naesiotus olla W.H. Dall, 1893 - (BULIMULIDAE)
- olla, Neverita olla M. de Serres, 1829 † - (NATICIDAE) (FOSSIL)
- olla, Natica olla P.M.T. de Serres, 1829 - syn of: Neverita josephinia (A. Risso, 1826) - (NATICIDAE)
- olla, Cymbium olla (C. Linnaeus, 1758) - (VOLUTIDAE)
- olla subglaucinoides, Neverita olla subglaucinoides A.V.M.D. D'Orbigny, 1852 † - (NATICIDAE) (FOSSIL)
- Ollaphon, Genus Ollaphon T. Iredale, 1929 (FASCIOLARIIDAE)
- olleri, Moitessieria olleri C. Altimira, 1960 - (MOITESSIERIIDAE)
- ollioulensis, Ortizius ollioulensis J.R. Bourguignat, 1884 - syn of: Ortizius navarricus (J.R. Bourguignat, 1870) - (OXYCHILIDAE)
- ollonense, Glottoceras ollonense W.M. Gabb, 1877 † - (KNEMICERATIDAE) (FOSSIL)
- ollulus, Myxas ollulus A.A. Gould, 1859 - (LYMNAEIDAE)
- olmosensis, Bostryx olmosensis A.S.H. Breure, 1978 - (BULIMULIDAE)
- olmosensis, Thaumastus olmosensis A. Zilch, 1954 - (MEGASPIRIDAE)
- olomea, Nassarius olomea E.A. Kay, 1979 - (NASSARIIDAE)
- olonkini, Lyonsia olonkini T. Soot-Ryen, 1932 - syn of: Lyonsia arenosa (H.P.C. Møller, 1842) - (LYONSIIDAE)
- olopana, Haminoea olopana H.A. Pilsbry, 1921 - syn of: Liloa porcellana (A.A. Gould, 1859) - (HAMINOEIDAE)
- olorina, Mactra olorina R.A. Philippi, 1846 - (MACTRIDAE)
- olorina, Anatina olorina L.A. Reeve, 1860 - syn of: Laternula rostrata (G.B. II Sowerby, 1839) - (MACTRIDAE)
- olorinella, Americoliva reticularis olorinella (P.L. Duclos, 1835) - (OLIVIDAE)
- olorus, Spyroceras olorus (J.W. Hall, 1879 †) - (SPYROCERATIDAE) (FOSSIL)
- olrikii, Cratena olrikii (O.A.L. Mörch, 1857) - (FACELINIDAE)
- olrikki, Cuthona olrikki O.A.L. Mörch, 1857 - syn of: Diaphoreolis viridis (E. Forbes, 1840) - (FIONIDAE)
- olseni, Sanguinolites olseni A.W. Grabau, 1931 † - (SANGUINOLITIDAE) (FOSSIL)
- olsoni, Spirancilla olsoni (P.A. Maxwell, 1992 †) - (ANCILLARIIDAE) (FOSSIL)
- olsoni, Amalda olsoni A.G. Beu, 1970 † - (ANCILLARIIDAE) (FOSSIL)
- olsoni, Cominella olsoni (R.K. Dell, 1956) - (BUCCINIDAE)
- olsoni, Eucominia olsoni R.K. Dell, 1956 - syn of: Cominella olsoni (R.K. Dell, 1956) - (BUCCINIDAE)
- olsoni, Palaeomphalus olsoni Rohr, 1980 † - (HELICOTOMIDAE) (FOSSIL)
- olsoni, Gegania olsoni (P.A. Maxwell, 1969 †) - (MATHILDIDAE) (FOSSIL)
- Olssonella, syn of: Genus Axelella R. Petit, 1988 (CANCELLARIIDAE)
- olssoni, Anadara olssoni Clark & J.W. Durham, 1946 † - (ARCIDAE) (FOSSIL)
- olssoni, Cantharus olssoni E.J. Petuch, 1994 † - (BUCCINIDAE) (FOSSIL)
- olssoni, Metula olssoni W.P. Woodring, 1928 - (BUCCINIDAE)
- olssoni, Calliostoma olssoni C.J. Maury, 1925 † - (CALLIOSTOMATIDAE) (FOSSIL)
- olssoni, Calliostoma olssoni C.J. Maury, 1925 † - syn of: Calliostoma olssoni C.J. Maury, 1925 † - (CALLIOSTOMATIDAE) (FOSSIL)
- olssoni, Calliostoma olssoni F.M. Bayer, 1971 - syn of: Calliostoma axelolssoni J.F. Quinn, 1992 - (CALLIOSTOMATIDAE)
- olssoni, Bonellitia olssoni Rivera, 1957 † - (CANCELLARIIDAE) (FOSSIL)
- olssoni, Hedecardium olssoni J. Marwick, 1944 † - (CARDIIDAE) (FOSSIL)
- olssoni, Euglyphostoma olssoni W.P. Woodring, 1970 † - (CLATHURELLIDAE) (FOSSIL)
- olssoni, Incaglaia adusta olssoni (H.A. Pilsbry, 1949) - (CLAUSILIIDAE)
- olssoni, Strombinella olssoni W.P. Woodring & A.A. Olsson, 1957 † - (COLUMBELLIDAE) (FOSSIL)
- olssoni, Lirastrombina olssoni (Perrilliat, 1972 †) - (COLUMBELLIDAE) (FOSSIL)
- olssoni, Nassarina olssoni C.J. Maury, 1917 † - (COLUMBELLIDAE) (FOSSIL)
- olssoni, Sinaxila tumbezia olssoni (T. Oinomikado, 1939 †) - (COLUMBELLIDAE) (FOSSIL)
- olssoni, Atlanticonus olssoni (C.J. Maury, 1917 †) - (CONIDAE) (FOSSIL)
- olssoni, Vexillum olssoni J.T.L. McGinty, 1955 - syn of: Nodicostellaria laterculata (G.B. II Sowerby, 1874) - (COSTELLARIIDAE)
- olssoni, Pachybathron olssoni A. Wakefield, F. Boyer & T. McCleery, 2002 - (CYSTISCIDAE)
- olssoni, Epiphragmophora olssoni H.A. Pilsbry, 1926 - (EPIPHRAGMOPHORIDAE)
- olssoni, Melanella olssoni P. Bartsch, 1924 - (EULIMIDAE)
- olssoni, Glyptostyla olssoni Clark & J.W. Durham 1946 † - (FASCIOLARIIDAE) (FOSSIL)
- olssoni, Pleuroploca olssoni (Anderson, 1929 †) - (FASCIOLARIIDAE) (FOSSIL)
- olssoni, Mancorus olssoni Clark & J.W. Durham, 1946 † - (FASCIOLARIIDAE) (FOSSIL)
- olssoni, Peruficus olssoni Clark & J.W. Durham, 1946 † - syn of: Glyptostyla olssoni Clark & J.W. Durham 1946 † - (FASCIOLARIIDAE) (FOSSIL)
- olssoni, Fasciolaria olssoni Anderson, 1929 † - syn of: Pleuroploca olssoni (Anderson, 1929 †) - (FASCIOLARIIDAE) (FOSSIL)
- olssoni, Aturoidea olssoni Miller, 1947 † - (HERCOGLOSSIDAE) (FOSSIL)
- olssoni, Fimbria olssoni H.G. Richards, 1953 † - (LUCINIDAE) (FOSSIL)
- olssoni, Vokesimurex olssoni (E.H. Vokes, 1967) - (MURICIDAE)
- olssoni, Typhina olssoni A.M. Keen, 1943 † - (MURICIDAE) (FOSSIL)
- olssoni, Eupleura olssoni E.H. Vokes, 1989 † - (MURICIDAE) (FOSSIL)
- olssoni, Dermomurex olssoni E.H. Vokes, 1989 - (MURICIDAE)
- olssoni, Diplodontites olssoni H.A. Pilsbry, 1933 - (MYCETOPODIDAE)
- olssoni, Globinassa olssoni E.J. Petuch, 1994 † - (NASSARIIDAE) (FOSSIL)
- olssoni, Calacyclotus olssoni (H.A. Pilsbry, 1926) - (NEOCYCLOTIDAE)
- olssoni, Eontia olssoni (L.G. Sheldon & C.J. Maury, 1922) - (NOETIIDAE)
- olssoni, Sheldonella olssoni L.G. Sheldon & C.J. Maury, 1922 - syn of: Eontia olssoni (L.G. Sheldon & C.J. Maury, 1922) - (NOETIIDAE)
- olssoni, Olivella olssoni C.O. Van Regteren Altena, 1971 - (OLIVELLIDAE)
- olssoni, Oliva olssoni E.J. Petuch & D.M. Sargent, 1986 - (OLIVIDAE)
- olssoni, Chondropoma olssoni H.A. Pilsbry, 1933 - (POMATIIDAE)
- olssoni, Compsodrillia olssoni J.H. McLean & L.H. Poorman, 1971 - (PSEUDOMELATOMIDAE)
- olssoni, Longchaeus olssoni (C.J. Maury, 1917 †) - (PYRAMIDELLIDAE) (FOSSIL)
- olssoni, Odostomia olssoni P. Bartsch, 1924 - (PYRAMIDELLIDAE)
- olssoni, Pyramimitra olssoni K.V.W. Palmer, 1938 † - (PYRAMIMITRIDAE) (FOSSIL)
- olssoni, Ectinochilus olssoni Clark & J.W. Durham, 1946 † - (RIMELLIDAE) (FOSSIL)
- olssoni, Guestieria olssoni H.A. Pilsbry, 1932 - (SCOLODONTIDAE)
- olssoni, Occulator olssoni H.A. Pilsbry, 1926 - syn of: Calacyclotus olssoni (H.A. Pilsbry, 1926) - (SCOLODONTIDAE)
- olssoni, Spondylus olssoni Clark & J.W. Durham, 1946 † - (SPONDYLIDAE) (FOSSIL)
- olssoni, Thyasira olssoni Clark & J.W. Durham, 1946 † - (THYASIRIDAE) (FOSSIL)
- olssoni, Teinostoma olssoni B.M. Landau, F. Da Silva & S.M. Heitz, 2016 † - (TORNIDAE) (FOSSIL)
- olssoni, Hystrivasum olssoni E.H. Vokes, 1966 † - (TURBINELLIDAE) (FOSSIL)
- olssoni, Andicula olssoni Rivera, 1957 † - (TURRIDAE) (FOSSIL)
- olssoni, Turritella olssoni Clark & J.W. Durham, 1946 † - (TURRITELLIDAE) (FOSSIL)
- olssoni, Vascoceras olssoni Chudeau, 1909 † - syn of: Paravascoceras cauvini (Chudeau, 1909 †) - (VASCOCERATIDAE) (FOSSIL)
- olssoni, Megapitaria olssoni Marks 1951 † - (VENERIDAE) (FOSSIL)
- olssoni, Petricola olssoni F.R. Bernard, 1983 - (VENERIDAE)
- olssoni, Chionopsis olssoni E. Fischer-Piette, 1969 - syn of: Chionopsis lilacina (Carpenter, 1864) - (VENERIDAE)
- olssoni, Pavora olssoni Clark & J.W. Durham, 1946 † - (VOLUTIDAE) (FOSSIL)
- olssoni, Athleta olssoni (Plummer, 1933 †) - (VOLUTIDAE) (FOSSIL)
- olssoni, Volutocorbis olssoni Plummer, 1933 † - syn of: Athleta olssoni (Plummer, 1933 †) - (VOLUTIDAE) (FOSSIL)
- olssoni gracilis, Athleta olssoni gracilis Garvie, 2013 † - (VOLUTIDAE) (FOSSIL)
- olstadi, Philobrya olstadi (T. Soot-Ryen, 1951) - (PHILOBRYIDAE)
- oltenensis, Viviparus achatinoides oltenensis Lubenescu & Zazuleac, 1985 † - (VIVIPARIDAE) (FOSSIL)
- olteniae, Stenothyrella olteniae Pana in Pana & al., 1981 † - (STENOTHYRIDAE) (FOSSIL)
- olteniana, Lytopelte olteniana A.V. Grossu, 1964 - (LIMACIDAE)
- oltinus, Limax oltinus H.R. Simroth, 1912 - syn of: Vitrinoides koenigi H.R. Simroth, 1912 - (LIMACIDAE)
- oltisana, Aegopinella oltisana P. Fagot, 1883 - syn of: Aegopinella nitidula (J.P.R. Draparnaud, 1805) - (ZONITIDAE)
- oltisiana, Helix oltisiana É.A.A. Locard, 1890 - syn of: Chilostoma squammatinum (A. Moquin-Tandon, 1855) - (HELICIDAE)
- oltmansianus, Conus oltmansianus C. van Lennep, 1876 - syn of: Sciteconus gradatulus (H.C. Weinkauff, 1875) - (CONIDAE)
- oltszakadatensis, Melanopsis oltszakadatensis Halaváts, 1914 † - (MELANOPSIDAE) (FOSSIL)
- oluae, Pyropelta oluae A. Warén & P. Bouchet, 2009 - (PYROPELTIDAE)
- olunguis, Scutus olunguis T. Iredale, 1940 - (FISSURELLIDAE)
- olutoroensis, Yoldiella olutoroensis O.A. Scarlato, 1981 - (YOLDIIDAE)
- olydium, Canarium olydium (P.L. Duclos, 1844) - (STROMBIDAE)
- olydius, Strombus olydius P.L. Duclos, 1844 - syn of: Canarium olydium (P.L. Duclos, 1844) - (STROMBIDAE)
- Olygoptycha, syn of: Genus Idyla H. Adams & A. Adams, 1855 (CLAUSILIIDAE)
- Olygyra, Genus Olygyra T. Say, 1818 (HELICINIDAE)
- Olympia, syn of: Genus Olympicola P. Hesse, 1916 (CLAUSILIIDAE)
- olympiadina, Oliva olympiadina P.L. Duclos, 1835 - syn of: Miniaceoliva tremulina (J.B.P.A. Lamarck, 1811) - (OLIVIDAE)
- olympiae, Terebellum olympiae Rolando, 2001 † - (SERAPHSIDAE) (FOSSIL)
- olympiana, Portlandia olympiana Clark † - syn of: Portlandella watasei (K. Kanehara, 1937 †) - (YOLDIIDAE) (FOSSIL)
- olympica, Olympicola olympica (L. Pfeiffer, 1848) - (CLAUSILIIDAE)
- olympica, Albinaria schuchii olympica H. Nordsieck, 1974 - (CLAUSILIIDAE)
- olympica, Campylaea trizona olympica (J.R. Roth, 1855) - (HELICIDAE)
- olympica, Vitrea olympica F. Riedel & F. Velkovrh, 1976 - (PRISTILOMATIDAE)
- olympicensis, Ophiodermella olympicensis W.O. Addicott, 1976 † - (BORSONIIDAE) (FOSSIL)
- Olympicola, Genus Olympicola P. Hesse, 1916 (CLAUSILIIDAE)
- Olympicosta, syn of: Genus Carinigera O.F. von Möllendorff, 1873 (CLAUSILIIDAE)
- olympicus, Buliminus olympicus W. Kobelt, 1877 - syn of: Chondrus zebrula (A.E.J. Férussac, 1821) - (ENIDAE)
- olympicus, Idas olympicus Kiel & Goedert 2007 † - (MYTILIDAE) (FOSSIL)
- olympicus, Oligolimax olympicus (B. Hausdorf, 1995) - (VITRINIDAE)
- olympicus brardus, Buliminus olympicus brardus J. Galland, 1884 - syn of: Chondrus zebrula (A.E.J. Férussac, 1821) - (ENIDAE)
- olympios, Pholeoteras olympios A. Reischütz, P.L. Reischütz & W. Fischer, 2008 - (LAURIIDAE)
- Olympus, Genus Olympus L.R.L. Simone, 2010 (CAMAENIDAE)
- olyra, Diaugasma olyra (L.A. Reeve, 1845) - (RAPHITOMIDAE)
- olyra, Pleurotoma olyra L.A. Reeve, 1845 - syn of: Diaugasma olyra (L.A. Reeve, 1845) - (TURRIDAE)
- omaensis, Brachystomia omaensis (S. Nomura, 1938) - (PYRAMIDELLIDAE)
- omagariense, Clinocardium omagariense Honda 1981 † - (CARDIIDAE) (FOSSIL)
- omagariensis, Hikidea omagariensis (A. Kaim & al., 2009 †) - (COLLONIIDAE) (FOSSIL)
- omagariensis, Cantrainea omagariensis A. Kaim & al., 2009 † - syn of: Hikidea omagariensis (A. Kaim & al., 2009 †) - (COLLONIIDAE) (FOSSIL)
- omagariensis, Serradonta omagariensis A. Kaim, B.W. Jenkins & Hikida, 2009 † - (PECTINODONTIDAE) (FOSSIL)
- omaguaca, Pisidium omaguaca C.F. Ituarte, 2005 - (SPHAERIIDAE)
- omahuensis, Duplicaria omahuensis (J. Marwick, 1926 †) - (TEREBRIDAE) (FOSSIL)
- omaicus, Conus omaicus C.H. Hwass in J.G. Bruguière, 1792 - syn of: Thalassiconus thomae (J.F. Gmelin, 1791) - (CONIDAE)
- Omaimaiceras, Subgenus Knemiceras (Omaimaiceras) Mahmoud, 1955 † (KNEMICERATIDAE) (FOSSIL)
- omala, Cernuella omala C.A. Westerlund, 1902 - syn of: Cernuella virgata (E.M. Da Costa, 1778) - (HYGROMIIDAE)
- Omala, Genus Omala H.C.F. Schumacher, 1817 (TELLINIDAE)
- OMALAXIDAE - syn of Family: TURRITELLIDAE
- Omalaxis, Genus Omalaxis Deshayes, 1830 † (TURRITELLIDAE) (FOSSIL)
- Omalenlina, Genus Omalenlina Liu, 1987 † (MOLLUSCA INCERTAE SEDIS) (FOSSIL)
- omaleyi, Daphnella omaleyi (J.C. Melvill, 1899) - (RAPHITOMIDAE)
- omaliana, Tychonia omaliana (de Koninck, 1844 †) - (ANOMPHALIDAE) (FOSSIL)
- omaliana, Grammysia omaliana (de Koninck) † - (GRAMMYSIIDAE) (FOSSIL)
- omalianus, Discitoceras omalianus (de Koninck, 1851 †) - (TRIGONOCERATIDAE) (FOSSIL)
- omalianus, Discites omalianus de Koninck, 1851 † - syn of: Discitoceras omalianus (de Koninck, 1851 †) - (TRIGONOCERATIDAE) (FOSSIL)
- omalica, Cretica tenuicostata omalica (C.A. Westerlund, 1884) - (CLAUSILIIDAE)
- omalii, Astarte omalii De la Jonkaire, 1823 † - (ASTARTIDAE) (FOSSIL)
- omalii, Mitra omalii Briart & Cornet, 1870 † - (MITRIDAE) (FOSSIL)
- omalii peelensis, Astarte omalii peelensis G. Spaink, 1968 † - (ASTARTIDAE) (FOSSIL)
- omalii scaldensis, Astarte omalii scaldensis A.W. Janssen & Van der Slik, 1974 † - (ASTARTIDAE) (FOSSIL)
- omalisma, Gonyodiscus rotundatus omalisma (P. Fagot, 1879) - (DISCIDAE)
- omaliusi, Genota omaliusi (M. Rouault, 1849 †) - (BORSONIIDAE) (FOSSIL)
- omaliusi, Pegophysema omaliusi (G.P. Deshayes, 1858 †) - (LUCINIDAE) (FOSSIL)
- Omalodiscus, syn of: Genus Anisus S.E. Studer, 1820 (PLANORBIDAE)
- Omalogyra, Genus Omalogyra J.G. Jeffreys, 1860 (OMALOGYRIDAE)
- OMALOGYRIDAE G.O.Sars, 1878 - Family (GASTROPODA-HETEROBRANCHIA [Subclass]-OMALOGYROIDEA [Superfamily])
- Omalogyrina, Subgenus Orbitestella (Omalogyrina) Ducasse & al., 1973 (ORBITESTELLIDAE)
- omalomphalus, Clanculus omalomphalus A. Adams, 1853 - syn of: Clanculus brunneus A. Adams, 1853 - (TROCHIDAE)
- Omalonyx, Genus Omalonyx D'Orbigny, 1841 (SUCCINEIDAE)
- omalos, Discopsis omalos (L. de Folin, 1870) - (TORNIDAE)
- Omalota, syn of: Genus Oxychilus L.I. Fitzinger, 1833 (OXYCHILIDAE)
- omalus, Anisus omalus (J.R. Bourguignat, 1881 †) - (PLANORBIDAE) (FOSSIL)
- omanense, Fragum omanense J.C. Melvill in J.C. Melvill & R. Standen, 1906 - syn of: Fragum sueziense (A. Issel, 1869) - (CARDIIDAE)
- omanensis, Limicolaria omanensis E. Neubert & D. Van Damme, 2012 † - syn of: Arabicolaria omanensis (E. Neubert & D. Van Damme, 2012 †) - (ACHATINIDAE) (FOSSIL)
- omanensis, Arabicolaria omanensis (E. Neubert & D. Van Damme, 2012 †) - (ANADROMIDAE) (FOSSIL)
- omanensis, Callistochiton omanensis P. Kaas & R.A. Van Belle, 1994 - (CALLISTOPLACIDAE)
- omanensis, Conasprella biraghii omanensis (L. Raybaudi Massilia, 1992) - (CONIDAE)
- omanensis, Mitromica omanensis M. Herrmann & S. Gori, 2012 - (COSTELLARIIDAE)
- omanensis, Chattina omanensis (E.A. Smith, 1906) - (CRASSATELLIDAE)
- omanensis, Cyrtorostra omanensis Dickins, 1999 † - (DELTOPECTINIDAE) (FOSSIL)
- omanensis, Drillia omanensis J.C. Melvill & R. Standen, 1901 - (DRILLIIDAE)
- omanensis, Eoacmaea omanensis (J.M.J. Christiaens, 1975) - (EOACMAEIDAE)
- omanensis, Rohillites omanensis Brühwiler & Bucher, 2012 † - (FLEMINGITIDAE) (FOSSIL)
- omanensis, Praetorreites omanensis Philipn & Platel 1994 † - (HIPPURITIDAE) (FOSSIL)
- omanensis, Echinolittorina omanensis D.G. Reid, 2007 - (LITTORINIDAE)
- omanensis, Megaxinus omanensis (E.A. Smith, 1906) - (LUCINIDAE)
- omanensis, Glabella omanensis F. Boyer, 2014 - (MARGINELLIDAE)
- omanensis, Aspella omanensis Houart, Gori & Rosado, 2017 - (MURICIDAE)
- omanensis, Muricopsis omanensis K.R. Smythe & P.G. Oliver, 1986 - (MURICIDAE)
- omanensis, Modiolus omanensis Hudson & Jefferies, 1961 † - (MYTILIDAE) (FOSSIL)
- omanensis, Phenacolepas omanensis H.E.J. Biggs, 1973 - (PHENACOLEPADIDAE)
- omanensis, Lodderena omanensis R.G. Moolenbeek, 1996 - (SKENEIDAE)
- omanensis, Eoquickia omanensis (E. Neubert & D. Van Damme, 2012 †) - (SUCCINEIDAE) (FOSSIL)
- omani, Galfettites omani Brühwiler & Bucher, 2012 † - (GALFETTITIDAE) (FOSSIL)
- omani, Sepia omani W. Adam & P.A. van Rees, 1966 - (SEPIIDAE)
- omanica, Pacaudiella omanica M. Harzhauser & T.A. Neubauer, 2015 † - (ANADROMIDAE) (FOSSIL)
- omanica, Costatoria omanica Diener, 1908 † - (MYOPHORIIDAE) (FOSSIL)
- omanicum, Tenuicerithium omanicum M. Harzhauser, 2007 † - (CERITHIIDAE) (FOSSIL)
- omanicum, Mongoloceras omanicum Glenister & Furnish, 1988 † - (MONGOLOCERATIDAE) (FOSSIL)
- omanicum, Vasum omanicum M. Harzhauser, 2007 † - (TURBINELLIDAE) (FOSSIL)
- Omanidacna, Genus Omanidacna Harzhauser & al., 2008 † (TRIDACNIDAE) (FOSSIL)
- Omanifera, Genus Omanifera H. Nordsieck, 2015 † (CLAUSILIIDAE) (FOSSIL)
- Omanillya, Genus Omanillya Nordsieck, 2015 † (CLAUSILIIDAE) (FOSSIL)
- Omanimaria, Genus Omanimaria Montenat, de Lapparent, Lys, Termier, Termier & Vachard, 1976 † (ARCHAEOGASTROPODA (UNASSIGNED)) (FOSSIL)
- Omanimerelina, Genus Omanimerelina R.G. Moolenbeek & C. Bosch, 2007 (RISSOIDAE)
- omanispinosa, Bayania omanispinosa M. Harzhauser, 2007 † - (THIARIDAE) (FOSSIL)
- Omanites, Genus Omanites Brühwiler & Bucher, 2012 † (MELAGATHICERATIDAE) (FOSSIL)
- Omanitopsis, Genus Omanitopsis Harzhauser & Neubauer, 2015 † (POMATIIDAE) (FOSSIL)
- omarai, Harpa omarai Abbass, 1967 † - (HARPIDAE) (FOSSIL)
- omari, Beyrichites omari F. Toula, 1896 † - syn of: Nicomedites barbarossae F. Toula, 1896 † - (BEYRICHITIDAE) (FOSSIL)
- omaria, Darioconus omaria (C.H. Hwass in J.G. Bruguière, 1792) - (CONIDAE)
- omaria, Conus omaria J.C. Melvill, 1900 - syn of: Darioconus pennaceus (I. von Born, 1778) - (CONIDAE)
- omaria magoides, Conus omaria magoides J.C. Melvill, 1900 - syn of: Darioconus omaria (C.H. Hwass in J.G. Bruguière, 1792) - (CONIDAE)
- omaria marmoricolor, Conus omaria marmoricolor J.C. Melvill, 1900 - syn of: Darioconus pennaceus (I. von Born, 1778) - (CONIDAE)
- ombracula, Patella ombracula H.M.D. de Blainville, 1819 - syn of: Umbraculum umbraculum (J. Lightfoot, 1786) - (PATELLIDAE)
- ombracula, Umbraculum ombracula H.M.D. de Blainville, 1819 - syn of: Umbraculum umbraculum (J. Lightfoot, 1786) - (UMBRACULIDAE)
- ombratus, Microlinices ombratus L.R.L. Simone, 2014 - (NATICIDAE)
- Ombrella, syn of: Genus Umbraculum H.C.F. Schumacher, 1817 (UMBRACULIDAE)
- ombronius, Aulacofusus ombronius (W.H. Dall, 1919) - (BUCCINIDAE)
- ombronius, Aulacofusus ombronius W.H. Dall, 1919 - syn of: Aulacofusus ombronius (W.H. Dall, 1919) - (BUCCINIDAE)
- omecatli, Lunatia omecatli Felix, 1891 † - syn of: Euspira praegrandis F.A. Roemer, 1849 † - (NATICIDAE) (FOSSIL)
- omega, Dawsonocerina omega (Barrande, 1874 †) - (DAWSONOCERATIDAE) (FOSSIL)
- omega, Oxynoe omega J.C. Melvill, 1918 - (OXYNOIDAE)
- omega, Volvatella omega (J.C. Melvill, 1918) - (VOLVATELLIDAE)
- Omegapilla, syn of: Genus Pupilla W.E. Leach in J. Fleming, 1828 (PUPILLIDAE)
- omeiensis, Ganesella omeiensis H.A. Pilsbry & T.C. Yen - (CAMAENIDAE)
- omeraensis, Texanites omeraensis Reeside, 1927 † - (COLLIGNONICERATIDAE) (FOSSIL)
- omia, Crassiclava omia (K.H. Barnard, 1958) - (PSEUDOMELATOMIDAE)
- omiae, Abralia omiae Z. Hidaka & T. Kubodera, 2000 - (ENOPLOTEUTHIDAE)
- omicron, Nautiliropa omicron (L. Pfeiffer, 1851) - (CHAROPIDAE)
- omicron, Amblychilepas omicron (J.C.H. Crosse, 1864) - (FISSURELLIDAE)
- omicron, Helix omicron L. Pfeiffer, 1851 - syn of: Nautiliropa omicron (L. Pfeiffer, 1851) - (HELICIDAE)
- omiensis, Bogoslovskya omiensis Niko, 2001 † - (BOGOSLOVSKYIDAE) (FOSSIL)
- omiensis, Aegista omiensis H.A. Pilsbry, 1902 - (BRADYBAENIDAE)
- omiensis, Cylindropalaina pusilla omiensis H.A. Pilsbry - (DIPLOMMATINIDAE)
- omiensis, Pseudodon omiensis H. von Heimburg, 1884 - (UNIONIDAE)
- omii, Palmulacypraea omii (H. Ikeda, 1998) - (CYPRAEIDAE)
- omissa, Archachatina omissa A.C. van Bruggen, 1965 - (ACHATINIDAE)
- omissa, Parabalea omissa (W.K. Weyrauch, 1957) - (CLAUSILIIDAE)
- omissa, Cavatidens omissa T. Iredale, 1930 - (LUCINIDAE)
- omissa, Vilitas omissa H.A. Pilsbry, 1926 - (THYSANOPHORIDAE)
- omissa, Pitar omissa (H.A. Pilsbry & H.N. Lowe, 1932) - (VENERIDAE)
- omissa, Transennella omissa (H.A. Pilsbry & H.N. Lowe, 1932) - syn of: Pitar omissa (H.A. Pilsbry & H.N. Lowe, 1932) - (VENERIDAE)
- omissum, Cerithium omissum C.É. Bayle, 1880 - syn of: Cerithium nodulosum J.G. Bruguière, 1792 - (CERITHIIDAE)
- omissum, Oistoceras omissum (C.T. Simpson, 1855 †) - (LIPAROCERATIDAE) (FOSSIL)
- omissus, Vermiculatus omissus (W.K. Weyrauch, 1967) - (BULIMULIDAE)
- omkutchanicum, Boreotrachyceras omkutchanicum (Bychkov, 1973 †) - (TRACHYCERATIDAE) (FOSSIL)
- omma, Aegista omma (H.A. Pilsbry & Y. Hirase, 1904) - (BRADYBAENIDAE)
- ommaensis, Megacardita ommaensis K. Ogasawara, 1977 † - (CARDITIDAE) (FOSSIL)
- Ommastrephes, Genus Ommastrephes D'Orbigny, 1834 (OMMASTREPHIDAE)
- OMMASTREPHIDAE Steenstrup, 1857 - Family (CEPHALOPODA-COLEOIDEA [Subclass]-DECAPODIFORMES [Superorder]-OEGOPSIDA [Order])
- Omniglypta, Genus Omniglypta J.T. Kuroda & T. Habe in T. Habe, 1953 (OMNIGLYPTIDAE)
- OMNIGLYPTIDAE Chistikov, 1975 - Family (SCAPHOPODA-DENTALIIDA [Order])
- omniliratus, Platygoniatites omniliratus Ruzhentsev & Bogoslovskaya, 1971 † - (DELEPINOCERATIDAE) (FOSSIL)
- omninolirata, Etrema crassilabrum omninolirata (R.P.J. Hervier, 1896) - (CLATHURELLIDAE)
- omnipurpurata, Turris omnipurpurata J.L. Vera-Peláez, R. Vega-Luz & M.C. Lozano, 2000 - (TURRIDAE)
- omnium, Orthoceras omnium Barrande, 1868 † - syn of: Temperoceras ludense (J. de C. Sowerby, 1839 †) - (ORTHOCERATIDAE) (FOSSIL)
- omnivaga, Xeromagna omnivaga É.A.A. Locard, 1899 - syn of: Xerosecta promissa C.A. Westerlund, 1893 - (HYGROMIIDAE)
- omnivagus, Pseudocatillus omnivagus Ebersin, 1967 † - (CARDIIDAE) (FOSSIL)
- Omnivenus, Genus Omnivenus Palmer, 1927 † (CARDIIDA (UNASSIGNED)) (FOSSIL)
- Omocyrtoceras, syn of: Genus Erioliceras Sepkoski Jr., 2002 † (BRANCOCERATIDAE) (FOSSIL)
- Omoderoceras, syn of: Genus Villania Till , 1909 † (PHRICODOCERATIDAE) (FOSSIL)
- Omogymna, Subgenus Oliva (Omogymna) E.C. Von Martens, 1897 (OLIVIDAE)
- omoia, Natica omoia J.F. Mabille & A. de Rochebrune, 1885 - (NATICIDAE)
- Omojuvavites, Genus Omojuvavites Tozer , 1994 † (JUVAVITIDAE) (FOSSIL)
- omoloiense, Arctoceras omoloiense Vavilov, 1969 † - (ARCTOCERATIDAE) (FOSSIL)
- omolonense, Uraloceras omolonense Bogoslovskaya & Boiko, 2002 † - (PARAGASTRIOCERATIDAE) (FOSSIL)
- omolonensis, Sphaerocladiscites omolonensis Bytschkov, 1976 † - (CLADISCITIDAE) (FOSSIL)
- omolonensis, Meleagrinella omolonensis Bytschkov, 1976 † - (OXYTOMIDAE) (FOSSIL)
- omolonica, Astartella omolonica Muromtseva, 1984 † - (ASTARTIDAE) (FOSSIL)
- omolonica, Edmondia omolonica Muromtseva, 1984 † - (EDMONDIIDAE) (FOSSIL)
- omoloniformica, Palaeocosmomya omoloniformica Guskov, 1984 † - (SANGUINOLITIDAE) (FOSSIL)
- omorii, Aegista tennissima omorii J.T. Kuroda, 1936 - (BRADYBAENIDAE)
- omoro, Satsuma omoro H. Minato, 1982 - (CAMAENIDAE)
- omoro bigibbosa, Satsuma omoro bigibbosa H. Minato, 1982 - (CAMAENIDAE)
- Omospira, Genus Omospira Ulrich & Scofield, 1897 † (LOXONEMATIDAE) (FOSSIL)
- omphale, Borsonella omphale W.H. Dall, 1919 - (BORSONIIDAE)
- omphalica, Sonninia omphalica Buckman † - (SONNINIIDAE) (FOSSIL)
- omphalicus, Prorsisphinctes omphalicus Buckman † - (PERISPHINCTIDAE) (FOSSIL)
- omphalina, Nesiohelix omphalina (Y. Hirase, 1915) - (BRADYBAENIDAE)
- Omphalina, Genus Omphalina C.S. Rafinesque, 1831 (ZONITIDAE)
- omphalina bipyramidalis, Nesiohelix omphalina bipyramidalis J.T. Kuroda & S. Emura, 1943 - (BRADYBAENIDAE)
- omphalina proximata, Nesiohelix omphalina proximata J.T. Kuroda & S. Emura, 1943 - (BRADYBAENIDAE)
- Omphalinella, Subgenus Patulopsis (Omphalinella) F.C. Baker, 1930 (ZONITIDAE)
- omphalis, Retusa omphalis O.A.L. Mörch, 1875 - (RETUSIDAE)
- omphalium, Pinacoceras omphalium Mojsisovics, 1873 † - syn of: Placites omphalius (Mojsisovics, 1873 †) - (PINACOCERATIDAE) (FOSSIL)
- omphalius, Placites omphalius (Mojsisovics, 1873 †) - (GYMNITIDAE) (FOSSIL)
- Omphalius, Genus Omphalius R.A. Philippi, 1847 (TEGULIDAE)
- Omphaloacteonella, Genus Omphaloacteonella Akopyan, 1972 (ACTEONIDAE)
- OMPHALOCIRRIDAE Wenz, 1938 † - Family (GASTROPODA-EOGASTROPODA [Subclass]-EUOMPHALINA [Order]-EUOMPHALOIDEA [Superfamily]) (FOSSIL)
- Omphalocirrus, Genus Omphalocirrus de Ryckholt, 1860 † (OMPHALOCIRRIDAE) (FOSSIL)
- Omphaloclathrum, syn of: Subgenus Venus (Antigona) H.C.F. Schumacher, 1817 (VENERIDAE)
- Omphaloconus, Genus Omphaloconus C.A. Westerlund, 1887 (ENIDAE)
- Omphalocrypta, Subgenus Choanomphalus (Omphalocrypta) J.R. le B. Tomlin, 1929 (PLANORBIDAE)
- omphalodes, Ampelita omphalodes (L. Pfeiffer, 1846) - (ACAVIDAE)
- omphalodes, Leptachatina omphalodes C.M.F. Ancey, 1899 - (AMASTRIDAE)
- omphalodes, Bulla omphalodes K.T. Menke, 1853 - syn of: Bulla striata J.G. Bruguière, 1792 - (BULLIDAE)
- omphalodes, Satsuma omphalodes H.A. Pilsbry, 1901 - (CAMAENIDAE)
- omphalodes, Leiostracus omphalodes (K.T. Menke, 1846) - (SIMPULOPSIDAE)
- omphalodes loucoubensis, Ampelita omphalodes loucoubensis J.C.H. Crosse - (ACAVIDAE)
- omphalodes subnigra, Ampelita omphalodes subnigra H.C. Fulton, 1901 - (ACAVIDAE)
- omphaloessa, Odostomia omphaloessa R.B. Watson, 1897 - (PYRAMIDELLIDAE)
- Omphalolimnus, syn of: Genus Lymnaea J.B.P.A. Lamarck, 1801 (LYMNAEIDAE)
- Omphalomargarites, Genus Omphalomargarites T. Habe & K. Itô, 1965 (TROCHIDAE)
- Omphalonema, Genus Omphalonema Grabau, 1936 † (ORIOSTOMATIDAE) (FOSSIL)
- omphalophora, Tacheocampylaea cyrniaca omphalophora (G. Dutailly, 1867) - (HELICIDAE)
- Omphalops, Subgenus Godwinia (Omphalops) F.C. Baker, 1941 (OXYCHILIDAE)
- Omphaloptycha, Genus Omphaloptycha Ammon, 1893 † (COELOSTYLINIDAE) (FOSSIL)
- Omphaloptychia, Genus Omphaloptychia von Ammon, 1893 † (COELOSTYLINIDAE) (FOSSIL)
- Omphalorissa, syn of: Genus Georissa W.T. Blanford, 1864 (HYDROCENIDAE)
- Omphaloropa, Genus Omphaloropa J. Stanisic, 1990 (CHAROPIDAE)
- Omphalosagda, Genus Omphalosagda Sandberger, 1872 † (ARCHAEOZONITIDAE) (FOSSIL)
- omphalospira, Amphicoelina omphalospira (O.F. von Möllendorff, 1897) - (PLECTOPYLIDAE)
- omphalostoma, Landouria omphalostoma B. Páll-Gergely & A. Hunyadi, 2013 - (CAMAENIDAE)
- Omphalostyla, syn of: Genus Limicolaria H.C.F. Schumacher, 1817 (ACHATINIDAE)
- OMPHALOTROCHIDAE Knight, 1945 † - Family (GASTROPODA-EOGASTROPODA [Subclass]-EUOMPHALINA [Order]-EUOMPHALOIDEA [Superfamily]) (FOSSIL)
- Omphalotrochus, Genus Omphalotrochus Meek, 1864 † (OMPHALOTROCHIDAE) (FOSSIL)
- Omphalotropis, Genus Omphalotropis L. Pfeiffer, 1851 (ASSIMINEIDAE)
- omphalotropis, Diala omphalotropis (K.H.J. Thiele, 1925) - (DIALIDAE)
- omphalotropis, Rissoella omphalotropis A. Adams, 1860 - (RISSOELLIDAE)
- omphalotropis, Ethalia omphalotropis A. Adams, 1863 - (TROCHIDAE)
- Omphalotukaia, Genus Omphalotukaia Yoshida, 1948 (CALLIOSTOMATIDAE)
- omphalotus, Choanomphalus omphalotus W. Dybowski, 1901 - (PLANORBIDAE)
- Omphalus, syn of: Genus Tegula R.P. Lesson, 1835 (TEGULIDAE)
- Omphiscola, Subgenus Stagnicola (Omphiscola) H.H. Beck, 1837 (LYMNAEIDAE)
- Omphix, Subgenus Mesomphix (Omphix) H.A. Pilsbry, 1911 (ZONITIDAE)
- omphloessa, Odostomia omphloessa R.B. Watson, 1897 - syn of: Odostomia omphaloessa R.B. Watson, 1897 - (PYRAMIDELLIDAE)
- omsiana, Lymnaea omsiana B. Hubendick, 1951 - syn of: Lymnaea araratensis N.D. Kruglov & Y.I. Starobogatov, 1985 - (LYMNAEIDAE)
- omuensis, Nassarius omuensis (H. Noda, 1980 †) - (NASSARIIDAE) (FOSSIL)
- Omulevia, Genus Omulevia Vostokova, 1964 † (RAPHISTOMATIDAE) (FOSSIL)
- Omulites, Genus Omulites Lyashenko, 1969 † (ROSSIITIDAE) (FOSSIL)
- onae, Camaena onae Thach, 2016 - (CAMAENIDAE)
- onagawaense, Styloptygma onagawaense (S. Nomura, 1938) - (PYRAMIDELLIDAE)
- onager, Lignus onager (R.J. Shuttleworth, 1856) - (ACHATINIDAE)
- onager, Eucithara onager S.M. Souverbie, 1875 - syn of: Eucithara conohelicoides (L.A. Reeve, 1846) - (MANGELIIDAE)
- onager, Cythara onager S.M. Souverbie, 1875 - syn of: Eucithara conohelicoides (L.A. Reeve, 1846) - (MANGELIIDAE)
- onager, Leiostracus onager (H.H. Beck, 1837) - (SIMPULOPSIDAE)
- onager subtuszonata, Leiostracus onager subtuszonata H.A. Pilsbry, 1899 - (SIMPULOPSIDAE)
- onairoensis, Saccella onairoensis (J. Marwick, 1926 †) - (NUCULANIDAE) (FOSSIL)
- onaneyi, Haplocochlias onaneyi J. Espinosa, J.A. Ortea & R. Fernández-Garcés, 2005 - (SKENEIDAE)
- onatensis, Alzoniella onatensis H.D. Boeters, 2003 - (HYDROBIIDAE)
- onca, Eurytus onca D'Orbigny, 1837 - syn of: Eurytus pentadinus (A.V.M.D. D'Orbigny, 1835) - (AMPHIBULIMIDAE)
- onca, Bulimus onca D'Orbigny, 1837 - syn of: Eurytus pentadinus (A.V.M.D. D'Orbigny, 1835) - (BULIMULIDAE)
- onca, Cypraea onca P.F. Röding, 1798 - syn of: Cypraea tigris C. Linnaeus, 1758 - (CYPRAEIDAE)
- onca, Helix onca D'Orbigny, 1837 - syn of: Eurytus pentadinus (A.V.M.D. D'Orbigny, 1835) - (HELICIDAE)
- onca, Naticarius onca (P.F. Röding, 1798) - (NATICIDAE)
- onca, Natica onca P.F. Röding, 1798 - syn of: Naticarius onca (P.F. Röding, 1798) - (NATICIDAE)
- onca, Plicatulostrea onca L.R.L. Simone & Amaral, 2008 - (PLICATULIDAE)
- onca, Isotriphora onca M.R. Fernandes, A. Pimenta & J.H. Leal, 2013 - (TRIPHORIDAE)
- Oncaea, syn of: Genus Achatina J.B.P.A. Lamarck, 1799 (ACHATINIDAE)
- oncalla, Corbicula oncalla P.M. Pallary, 1909 - syn of: Corbicula fluminalis (O.F. Müller, 1774) - (CYRENIDAE)
- oncera, Phosinella oncera (W.P. Woodring, 1957 †) - (RISSOINIDAE) (FOSSIL)
- onchidella, Prunum onchidella (W.H. Dall, 1890 †) - (MARGINELLIDAE) (FOSSIL)
- Onchidella, Genus Onchidella J.E. Gray, 1850 (ONCHIDIIDAE)
- Onchidiella, syn of: Genus Onchidella J.E. Gray, 1850 (ONCHIDIIDAE)
- ONCHIDIIDAE Rafinesque, 1815 - Family (GASTROPODA-HETEROBRANCHIA [Subclass]-PULMONATA [Infraclass]-SYSTELLOMMATOPHORA [Order]-ONCHIDIOIDEA [Superfamily])
- Onchidina, Genus Onchidina J.O. Semper, 1885 (ONCHIDIIDAE)
- onchidioides, Buchanania onchidioides R.P. Lesson, 1831 - (FISSURELLIDAE)
- Onchidiopsis, Genus Onchidiopsis L.S.R. Bergh, 1853 (VELUTINIDAE)
- Onchidiorus, syn of: Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- Onchidium, Genus Onchidium F. Buchannan, 1800 (ONCHIDIIDAE)
- Onchidora, syn of: Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- ONCHIDORIDIDAE Gray, 1827 - Family (GASTROPODA-HETEROBRANCHIA [Subclass]-OPISTHOBRANCHIA [Infraclass]-NUDIBRANCHIA [Order]-ONCHIDORIDOIDEA [Superfamily])
- Onchidoris, Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- Onchimira, Genus Onchimira A.V. Martynov, T.A. Korshunova & K. Sanamyan, 2009 (ONCHIDORIDIDAE)
- Onchis, syn of: Genus Peronia J. Fleming, 1822 (ONCHIDIIDAE)
- onchodes, Epitonium onchodes W.H. Dall, 1917 - syn of: Epitonium multicostatum (G.B. II Sowerby, 1844) - (EPITONIIDAE)
- onchodes, Limopsis onchodes W.H. Dall, 1927 - (LIMOPSIDAE)
- onchodes, Nassarius onchodes (W.H. Dall, 1917) - (NASSARIIDAE)
- Onchodia, Genus Onchodia W.H. Dall, 1924 (CERITHIOPSIDAE)
- Oncidella, syn of: Genus Onchidella J.E. Gray, 1850 (ONCHIDIIDAE)
- Oncidiella, syn of: Genus Onchidella J.E. Gray, 1850 (ONCHIDIIDAE)
- Oncidiodoris, syn of: Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- Oncidium, syn of: Genus Onchidium F. Buchannan, 1800 (ONCHIDIIDAE)
- Oncidoris, syn of: Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- Oncis, Genus Oncis H.P. Plate, 1893 (ONCHIDIIDAE)
- Oncoceras, Genus Oncoceras Hall, 1847 † (ONCOCERATIDAE) (FOSSIL)
- ONCOCERATIDAE Hyatt, 1883 † - Family (CEPHALOPODA-NAUTILOIDEA [Subclass]-ONCOCERIDA [Order]) (FOSSIL)
- ONCOCERIDA (UNASSIGNED) - Family (CEPHALOPODA-NAUTILOIDEA [Subclass]-ONCOCERIDA [Order]) (FOSSIL)
- oncoceroides, Xenoceras oncoceroides Flower † - (POTERIOCERATIDAE) (FOSSIL)
- oncochiliformis, Naticopsis oncochiliformis C. Gemmellaro, 1889 † - (DELPHINULOPSIDAE) (FOSSIL)
- Oncochilus, Genus Oncochilus von Zittel, 1882 † (NERITARIIDAE) (FOSSIL)
- oncoda, Neptunea oncoda W.H. Dall, 1907 - syn of: Neptunea oncodes (W.H. Dall, 1907) - (BUCCINIDAE)
- oncodes, Penion oncodes (R.A. Philippi, 1887 †) - (BUCCINIDAE) (FOSSIL)
- oncodes, Neptunea oncodes (W.H. Dall, 1907) - (BUCCINIDAE)
- oncodes, Neptunea oncodes W.H. Dall, 1907 - syn of: Neptunea oncodes (W.H. Dall, 1907) - (BUCCINIDAE)
- oncodes, Loochooia oncodes W.H. Dall, 1907 - syn of: Neptunea oncodes (W.H. Dall, 1907) - (BUCCINIDAE)
- oncodes, Donax oncodes A.E.M. Cossmann, 1886 † - (DONACIDAE) (FOSSIL)
- oncodes, Glauconome oncodes J.C. Melvill, 1897 - syn of: Glauconome cerea L.A. Reeve, 1844 - (GLAUCONOMIDAE)
- oncodes, Diplodonta oncodes A.E.M. Cossmann & M.A. Peyrot, 1911 † - (UNGULINIDAE) (FOSSIL)
- Oncodoris, syn of: Genus Onchidoris H.M.D. De Blainville, 1816 (ONCHIDORIDIDAE)
- Oncomelania, Genus Oncomelania Gradler, 1881 (POMATIOPSIDAE)
- oncophorae, Viviparus oncophorae Rzehak, 1893 † - (VIVIPARIDAE) (FOSSIL)
- oncophorus, Viviparus oncophorus Š. Brusina, 1874 † - (VIVIPARIDAE) (FOSSIL)
- oncospira, Tornatellides oncospira C.M. Cooke & H.A. Pilsbry, 1915 - (ACHATINELLIDAE)
- oncostomus, Gyraulus oncostomus (Š. Brusina, 1902) - (PLANORBIDAE)
- ondaense, Palaospeum hispanicum ondaense H.D. Boeters, 2003 - (MOITESSIERIIDAE)
- ondatiruga, Pleurotoma ondatiruga Ant. Bivona-Bernardi, 1838 - syn of: Fusiturris undatiruga (Ant. Bivona-Bernardi, 1838) - (TURRIDAE)
- ondina, Volvarina ondina J. Espinosa, L. Moro & J.A. Ortea, 2011 - (MARGINELLIDAE)
- Ondina, Genus Ondina L. de Folin, 1870 (PYRAMIDELLIDAE)
- ondulata, Oosterella ondulata Reboulet, 1996 † - (OOSTERELLIDAE) (FOSSIL)
- Ondulopsis, Genus Ondulopsis A. Cecalupo & I. Perugia, 2012 (CERITHIOPSIDAE)
- ondulum, Sedilia ondulum A.A. Olsson & A. Harbison, 1953 † - (HORAICLAVIDAE) (FOSSIL)
- onealensis, Cerithiopsis onealensis P. Bartsch, 1921 - (CERITHIOPSIDAE)
- oneida, Amnicola oneida H.A. Pilsbry, 1917 - (AMNICOLIDAE)
- oneili, Drillia oneili K.H. Barnard, 1958 - syn of: Thelecytharella oneili (K.H. Barnard, 1958) - (DRILLIIDAE)
- oneili, Granulina oneili J. Espinosa & J.A. Ortea, 2014 - (MARGINELLIDAE)
- oneili, Thelecytharella oneili (K.H. Barnard, 1958) - (PSEUDOMELATOMIDAE)
- oneili, Otitoma oneili (K.H. Barnard, 1958) - syn of: Thelecytharella oneili (K.H. Barnard, 1958) - (PSEUDOMELATOMIDAE)
- oneirophantae, Megadenus oneirophantae P. Bouchet & C.F. Lützen, 1980 - (EULIMIDAE)
- onekaka, Echyridella onekaka S.C. Fenwick & B.A. Marshall, 2006 - (HYRIIDAE)
- Oneotoceras, Genus Oneotoceras Ulrich, 1926 † (ELLESMEROCERATIDAE) (FOSSIL)
- onerata, Pleuromeris onerata (G.P. Deshayes, 1858 †) - (CARDITIDAE) (FOSSIL)
- onerata, Venericardia onerata (G.P. Deshayes †) - (CARDITIDAE) (FOSSIL)
- onerata, Nassa onerata G.P. Deshayes, 1863 - syn of: Nassarius oneratus (G.P. Deshayes, 1863) - (NASSARIIDAE)
- onerata, Haurakia onerata C.R. Laws, 1939 † - (RISSOIDAE) (FOSSIL)
- oneratum, Allumettoceras oneratum J. Evans, 1994 † - (TRIPTEROCERATIDAE) (FOSSIL)
- oneratus, Nassarius oneratus (G.P. Deshayes, 1863) - (NASSARIIDAE)
- oneroaense, Maoricardium oneroaense (Powell, 1938 †) - (CARDIIDAE) (FOSSIL)
- oneroaensis, Acteon oneroaensis Powell & J.A. Bartrum, 1929 † - (ACTEONIDAE) (FOSSIL)
- oneroaensis, Austrofusus oneroaensis Powell & J.A. Bartrum, 1929 † - (BUCCINIDAE) (FOSSIL)
- oneroaensis, Echinophoria oneroaensis (Powell, 1938 †) - (CASSIDAE) (FOSSIL)
- oneroaensis, Polinices oneroaensis Powell & J.A. Bartrum, 1929 † - (NATICIDAE) (FOSSIL)
- oneroaensis, Pteria oneroaensis (Powell & J.A. Bartrum, 1929 †) - (PTERIIDAE) (FOSSIL)
- oneroaensis, Bartrumia oneroaensis (Powell & J.A. Bartrum, 1929 †) - (TELLINIDAE) (FOSSIL)
- onerosus, Stegochiton onerosus Hoare & Smith, 1984 † - (LEPTOCHITONIDAE) (FOSSIL)
- onerosus, Stenopronorites onerosus Ruzhencev & Bogoslovskaya, 1978 † - (PRONORITIDAE) (FOSSIL)
- onestae, Onestia onestae (McLearn, 1931 †) - (CARDIIDAE) (FOSSIL)
- onestae, Corbula onestae McLearn, 1929 † - (CORBULIDAE) (FOSSIL)
- onestera, Ganesella onestera (J.F. Mabille, 1887) - (CAMAENIDAE)
- onestera, Helix onestera J.F. Mabille, 1887 - syn of: Ganesella onestera (J.F. Mabille, 1887) - (HELICIDAE)
- Onestia, Genus Onestia McLearn, 1933 † (CARDIIDAE) (FOSSIL)
- ongaroae, Eoplatyzona ongaroae Blodgett & al., 1999 † - (GOSSELETINIDAE) (FOSSIL)
- ongcopensis, Oscilla ongcopensis E. Saurin, 1962 - (PYRAMIDELLIDAE)
- Ongleya, Genus Ongleya Finlay & Marwick, 1937 † (ACTEONIDAE) (FOSSIL)
- ongleyi, Dimitobelus ongleyi Stevens, 1965 † - (DIMITOBELIDAE) (FOSSIL)
- ongleyi, Towaipecten ongleyi (J. Marwick, 1965 †) - (PECTINIDAE) (FOSSIL)
- ongleyi, Maoricolpus ongleyi J. Marwick, 1931 † - (TURRITELLIDAE) (FOSSIL)
- ongleyi, Dosinia ongleyi J. Marwick, 1927 † - (VENERIDAE) (FOSSIL)
- Ongoconus, syn of: Genus Kioconus A.J. Da Motta, 1991 (CONIDAE)
- ongurensis, Benedictia limnaeoides ongurensis Kozhov, 1936 - (LITHOGLYPHIDAE)
- onichidella, Microspira onichidella W.H. Dall, 1890 † - (MARGINELLIDAE) (FOSSIL)
- onilahyense, Barroisiceras onilahyense Basse, 1947 † - (COLLIGNONICERATIDAE) (FOSSIL)
- onimarensis, Kawanamia onimarensis T. Kase, 1988 † - (LOPHOSPIRIDAE) (FOSSIL)
- Onimusira, syn of: Subgenus Morum (Oniscidia) O.A.L. Mörch, 1852 (HARPIDAE)
- Onimusiro, syn of: Subgenus Morum (Oniscidia) O.A.L. Mörch, 1852 (HARPIDAE)
- Onischidea, syn of: Subgenus Morum (Oniscidia) O.A.L. Mörch, 1852 (HARPIDAE)
- Oniscia, syn of: Genus Morum P.F. Röding, 1798 (HARPIDAE)
- Oniscidea, syn of: Subgenus Morum (Oniscidia) O.A.L. Mörch, 1852 (HARPIDAE)
- Oniscidia, Subgenus Morum (Oniscidia) O.A.L. Mörch, 1852 (HARPIDAE)
- oniscinum, Pusia oniscinum (J.B.P.A. Lamarck, 1811) - (COSTELLARIIDAE)
- oniscioides, Onchidella oniscioides (H.M.D. de Blainville, 1816) - (ONCHIDIIDAE)
- oniscus, Cassidaria oniscus J.B.P.A. Lamarck, 1847 † - syn of: Oniscidia variolosum (J.P.S. Grateloup, 1834 †) - (CASSIDAE) (FOSSIL)
- oniscus, Conus oniscus W.P. Woodring, 1928 † - (CONIDAE) (FOSSIL)
- oniscus, Corbula oniscus T.A. Conrad, 1833 † - (CORBULIDAE) (FOSSIL)
- oniscus, Cypraea oniscus P.F. Röding, 1798 - syn of: Pusula pediculus (C. Linnaeus, 1758) - (CYPRAEIDAE)
- oniscus, Cypraea oniscus P.F. Röding, 1798 - syn of: Pusula pediculus (C. Linnaeus, 1758) - (CYPRAEIDAE)
- oniscus, Morum oniscus (C. Linnaeus, 1767) - (HARPIDAE)
- oniscus, Ischnochiton oniscus (C.F.F. von Krauss, 1848) - (ISCHNOCHITONIDAE)
- oniscus, Ostrea oniscus E.C. Von Martens, 1899 - syn of: Nanostrea fluctigera (F.P. Jousseaume in É. Lamy, 1925) - (OSTREIDAE)
- oniscus, Niveria oniscus P.F. Röding, 1798 - syn of: Pusula pediculus (C. Linnaeus, 1758) - (TRIVIIDAE)
- oniscus strombiformis, Morum oniscus strombiformis L.A. Reeve, 1842 - syn of: Morum strombiformis (L.A. Reeve, 1842) - (HARPIDAE)
- onishpetensis, Doliocassis onishpetensis Y. Otuka, 1937 † - (CASSIDAE) (FOSSIL)
- oniska, Oliva spicata oniska P.L. Duclos, 1844 - (OLIVIDAE)
- Onithella, syn of: Genus Onithochiton J.E. Gray, 1847 (CHITONIDAE)
- Onithochiton, Genus Onithochiton J.E. Gray, 1847 (CHITONIDAE)
- Onithoplax, syn of: Genus Onithochiton J.E. Gray, 1847 (CHITONIDAE)
- Onitshoceras, Genus Onitshoceras Reyment , 1954 † (DESMOCERATIDAE) (FOSSIL)
- onixiomicra, Pseudovestia onixiomicra J.R. Bourguignat, 1877 - syn of: Macrogastra rolphii (W. Turton, 1831) - (CLAUSILIIDAE)
- onixiomicra, Helix lucorum onixiomicra J.R. Bourguignat, 1860 - (HELICIDAE)
- onkastoma, Austrocypraea onkastoma A.E.M. Cossmann, 1903 † - (CYPRAEIDAE) (FOSSIL)
- Onkogrypha, Genus Onkogrypha Spriestersbach, 1925 † (BIVALVIA INCERTAE SEDIS) (FOSSIL)
- Onkospira, Genus Onkospira Zittel, 1873 † (EUCYCLIDAE) (FOSSIL)
- onna, Halgerda onna S.J. Fahey & T.M. Gosliner, 2001 - (DISCODORIDIDAE)
- onnaica, Trominina onnaica (Yokoyama, 1932 †) - (BUCCINIDAE) (FOSSIL)
- onoae, Volvulella onoae Á. Valdés, 2008 - (RHIZORIDAE)
- Onoba, Genus Onoba H. Adams & A. Adams, 1852 (RISSOIDAE)
- onobiformis, Ailinzebina onobiformis (E. Rolán & L. Luque, 2000) - (RISSOINIDAE)
- Onobops, Genus Onobops F.G. Thompson, 1969 (COCHLIOPIDAE)
- Onoceras, Genus Onoceras Swartz & Prouty, 1923 † (ONCOCERATIDAE) (FOSSIL)
- Onodon, syn of: Genus Anodonta J.B.P.A. Lamarck, 1799 (UNIONIDAE)
- onoense, Hypophylloceras onoense (Stanton, 1895 †) - (PHYLLOCERATIDAE) (FOSSIL)
- onoensis, Diplommatina tosana onoensis H.A. Pilsbry & Y. Hirase, 1904 - (DIPLOMMATINIDAE)
- onoensis, Phanerolepida onoensis A. Kaim & al., 2014 † - (TURBINIDAE) (FOSSIL)
- onogoensis, Viviparus onogoensis T. Kobayashi & M. Suzuki, 1943 † - (VIVIPARIDAE) (FOSSIL)
- onoi, Bicarina onoi T. Kase & Nishida, 1986 † - (GOSSELETINIDAE) (FOSSIL)
- onoi, Anasibirites onoi (Yehara, 1925 †) - (MELAGATHICERATIDAE) (FOSSIL)
- onokeana, Cominella onokeana (L. C. King, 1933 †) - (BUCCINIDAE) (FOSSIL)
- onokeana, Comitas onokeana King, 1933 - (PSEUDOMELATOMIDAE)
- onokeana vivens, Comitas onokeana vivens R.K. Dell, 1956 - (PSEUDOMELATOMIDAE)
- Onoketoma, Genus Onoketoma Beu, 2011 † (RAPHITOMIDAE) (FOSSIL)
- ononensis, Anodonta ononensis I. Lea, 1870 - syn of: Cristaria plicata (W.E. Leach, 1815) - (UNIONIDAE)
- onorensis, Malletia onorensis Lautenschläger, 1964 † - (MALLETIIDAE) (FOSSIL)
- onoua, Teremelon onoua J.D. Stilwell, 2016 † - (VOLUTIDAE) (FOSSIL)
- onowensis, Anodonta onowensis I. Lea, 1852 - syn of: Cristaria plicata (W.E. Leach, 1815) - (UNIONIDAE)
- onslowensis, Astarte onslowensis Kellum, 1926 † - (ASTARTIDAE) (FOSSIL)
- onslowensis, Spinifulgur onslowensis (Kellum, 1926 †) - (BUSYCONIDAE) (FOSSIL)
- onslowensis, Busycon spiniger onslowensis H.G. Richards, 1943 - (BUSYCONIDAE)
- onslowensis, Terebra onslowensis E.J. Petuch, 1974 - syn of: Terebra dislocata onslowensis (E.J. Petuch, 1974) - (TEREBRIDAE)
- onslowensis, Terebra dislocata onslowensis (E.J. Petuch, 1974) - (TEREBRIDAE)
- onslowi, Bothriembryon onslowi (J.C. Cox, 1864) - (BOTHRIEMBRYONTIDAE)
- onslowi, Liparus onslowi H.H. Smith, 1894 - syn of: Bothriembryon costulatus (J.B.P.A. Lamarck, 1822) - (BOTHRIEMBRYONTIDAE)
- onslowi, Charopa onslowi J.W. Brazier, 1871 - syn of: Elsothera ricei (J.W. Brazier, 1871) - (CHAROPIDAE)
- onslowi, Helix onslowi J.W. Brazier, 1871 - syn of: Elsothera ricei (J.W. Brazier, 1871) - (HELICIDAE)
- onslowi hartogensis, Bothriembryon onslowi hartogensis W. Kobelt, 1901 - syn of: Bothriembryon costulatus (J.B.P.A. Lamarck, 1822) - (BOTHRIEMBRYONTIDAE)
- onslowi minor, Bothriembryon onslowi minor H.A. Pilsbry, 1900 - syn of: Bothriembryon costulatus (J.B.P.A. Lamarck, 1822) - (BOTHRIEMBRYONTIDAE)
- Ontaria, Genus Ontaria † (LUNULACARDIIDAE) (FOSSIL)
- ontariensis, Valvata sincera ontariensis H.B. Baker, 1931 - (VALVATIDAE)
- ontarioense, Phragmoceras ontarioense Foerste, 1929 † - (PHRAGMOCERATIDAE) (FOSSIL)
- ontarioensis, Valvata lewisi ontarioensis H.B. Baker, 1931 - (VALVATIDAE)
- ontragnana, Toxoconcha ontragnana E.A.L. Kittl, 1899 † - (PROTORCULIDAE) (FOSSIL)
- onubensis, Spurilla onubensis L. Carmona, B.R. Lei, M. Pola & al., 2014 - syn of: Spurilla croisicensis (A. Labbé, 1923) - (AEOLIDIIDAE)
- onubensis, Jorunna onubensis J.L. Cervera, J.C. García-Gómez & F.J. García, 1986 - (DISCODORIDIDAE)
- onubensis, Gasullia onubensis A. Ortiz De Zárate, 1991 - syn of: Gasullia gasulli (A. Ortiz De Zárate, 1961) - (HELICODONTIDAE)
- onukii, Aviculopecten onukii Murata, 1969 † - (AVICULOPECTINIDAE) (FOSSIL)
- onukii, Acanthopecten onukii Murata, 1964 † - (LIMIPECTINIDAE) (FOSSIL)
- onukii, Ensipteria onukii Nakazawa & Newell, 1968 † - (PTERIIDA (UNASSIGNED)) (FOSSIL)
- onuphria, Florisarka onuphria T. Iredale, 1936 - syn of: Hiatula alba (J.B.P.A. Lamarck, 1818) - (PSAMMOBIIDAE)
- onuri, Hydrobia onuri Taner, 1974 † - (HYDROBIIDAE) (FOSSIL)
- onusta, Chondrina onusta G.B. Adami, 1886 - syn of: Chondrina avenacea (J.G. Bruguière, 1792) - (CHONDRINIDAE)
- onusta, Doto onusta P. Hesse, 1872 - (DOTIDAE)
- onusta, Melanopsis onusta Stefanescu, 1896 † - (MELANOPSIDAE) (FOSSIL)
- ONUSTIDAE - syn of Family: XENOPHORIDAE
- Onustis, syn of: Genus Onustus W.J. Swainson, 1840 (XENOPHORIDAE)
- onustum, Selastele onustum (N.H. Odhner, 1924) - (CALLIOSTOMATIDAE)
- onustus, Polinices onustus (R.P. Whitfield, 1865 †) - (NATICIDAE) (FOSSIL)
- Onustus, Genus Onustus W.J. Swainson, 1840 (XENOPHORIDAE)
- onustus, Xenophora onustus L.A. Reeve, 1842 - syn of: Xenophora conchyliophora (I. von Born, 1780) - (XENOPHORIDAE)
- onychia, Radix onychia (C.A. Westerlund, 1887) - (LYMNAEIDAE)
- onychia, Melanopsis onychia Š. Brusina, 1874 † - (MELANOPSIDAE) (FOSSIL)
- Onychia, syn of: Genus Onykia C.A. Lesueur, 1821 (ONYCHOTEUTHIDAE)
- onychina, Eulima onychina L. de Folin, 1867 - syn of: Eulima bifasciata D'Orbigny, 1841 - (EULIMIDAE)
- onychina, Lottia onychina A.A. Gould, 1852 - syn of: Lottia subrugosa (A.V.M.D. D'Orbigny, 1846) - (LOTTIIDAE)
- onychina, Marginella onychina A. Adams & L.A. Reeve, 1850 - syn of: Cryptospira tricincta (R.B. Hinds, 1844) - (MARGINELLIDAE)
- Onychina, syn of: Genus Neritina J.B.P.A. Lamarck, 1816 (NERITIDAE)
- onychitis, Acmaea onychitis K.T. Menke, 1843 - syn of: Lottia onychitis (K.T. Menke, 1843) - (ACMAEIDAE)
- onychitis, Lottia onychitis (K.T. Menke, 1843) - (LOTTIIDAE)
- Onychoceras, Genus Onychoceras Wunstrorf , 1905 † (HAMMATOCERATIDAE) (FOSSIL)
- ONYCHOCHILIDAE Koken, 1925 † - Family (MOLLUSCA INCERTAE SEDIS-MIMOSPIRIDA [Order]-CLISOSPIROIDEA [Superfamily]) (FOSSIL)
- Onychochilus, Genus Onychochilus Lindström, 1884 † (ONYCHOCHILIDAE) (FOSSIL)
- onychoides, Cornisepta onychoides (D.G. Herbert & R.N. Kilburn, 1986) - (FISSURELLIDAE)
- ONYCHOTEUTHIDAE Gray, 1847 - Family (CEPHALOPODA-COLEOIDEA [Subclass]-DECAPODIFORMES [Superorder]-OEGOPSIDA [Order])
- Onychoteuthis, Genus Onychoteuthis A.A.H. Lichtenstein, 1818 (ONYCHOTEUTHIDAE)
- onycina, Luria onycina G.S. Coen, 1949 - syn of: Luria lurida (C. Linnaeus, 1758) - (CYPRAEIDAE)
- Onycochilus, syn of: Genus Onychochilus Lindström, 1884 † (ONYCHOCHILIDAE) (FOSSIL)
- Onykia, Genus Onykia C.A. Lesueur, 1821 (ONYCHOTEUTHIDAE)
- onyx, Acanthochitona onyx L. Spengler, 1797 - syn of: Acanthochitona crinita (T. Pennant, 1777) - (ACANTHOCHITONIDAE)
- onyx, Crepidula onyx Sowerby, 1824 - (CALYPTRAEIDAE)
- onyx, Crepidula onyx auct. non G.B. I Sowerby, 1824 - syn of: Crepidula cachimilla Cledón, L.R.L. Simone & P.E. Penchaszadeh, 2004 - (CALYPTRAEIDAE)
- onyx, Chiton onyx L. Spengler, 1797 - syn of: Acanthochitona crinita (T. Pennant, 1777) - (CHITONIDAE)
- onyx, Erronea onyx (C. Linnaeus, 1758) - (CYPRAEIDAE)
- onyx, Erronea onyx J.E. Gray, 1828 - syn of: Erronea onyx succincta (C. Linnaeus, 1758) - (CYPRAEIDAE)
- onyx, Diplommatina onyx H.C. Fulton, 1901 - (DIPLOMMATINIDAE)
- onyx, Gonatus onyx A.T. Young, 1972 - (GONATIDAE)
- onyx adusta, Erronea onyx adusta J.B.P.A. Lamarck, 1810 - syn of: Erronea adusta (J.B.P.A. Lamarck, 1810) - (CYPRAEIDAE)
- onyx draco, Erronea onyx draco Bergonzoni, 2013 - (CYPRAEIDAE)
- onyx melanesiae, Erronea onyx melanesiae F.A. Schilder & M. Schilder, 1937 - syn of: Erronea adusta melanesiae F.A. Schilder & M. Schilder, 1937 - (CYPRAEIDAE)
- onyx succincta, Erronea onyx succincta (C. Linnaeus, 1758) - (CYPRAEIDAE)
- Onyxites, Genus Onyxites Zhuravleva, 1972 † (DISCOSORIDA (UNASSIGNED)) (FOSSIL)
- onyxoides, Capulus onyxoides A.E.M. Cossmann, 1896 - (CAPULIDAE)
- onzikuensis, Paracingulina onzikuensis (S. Nomura, 1938) - (PYRAMIDELLIDAE)
- onzola, Clathrodrillia onzola A.A. Olsson, 1964 † - syn of: Clathrodrillia gatunensis (F. Toula, 1909 †) - (DRILLIIDAE) (FOSSIL)
- Oobolma, syn of: Genus Bolma A. Risso, 1826 (TURBINIDAE)
- Ooceras, Genus Ooceras Ruedemann, 1906 † (OONOCERATIDAE) (FOSSIL)
- Oocerina, Genus Oocerina Foerste, 1926 † (ONCOCERATIDAE) (FOSSIL)
- Oochiton, Genus Oochiton E.A. Ashby, 1929 (LORICIDAE)
- Oocoris, syn of: Genus Oocorys P. Fischer, 1883 (CASSIDAE)
- Oocorys, Genus Oocorys P. Fischer, 1883 (CASSIDAE)
- oodes, Persicula oodes J.C. Melvill, 1898 - (CYSTISCIDAE)
- oodes, Pyrgulina oodes (R.B. Watson, 1886) - (PYRAMIDELLIDAE)
- oodnadattaense, Labeceras oodnadattaense Reyment, 1964 † - (LABECERATIDAE) (FOSSIL)
- ooformis, Limulatys ooformis (T. Habe, 1964) - (HAMINOEIDAE)
- ooharai, Selenophaedusa ooharai H. Nordsieck, 2007 - (CLAUSILIIDAE)
- ooharai, Formosana ooharai H. Nordsieck, 2007 - (CLAUSILIIDAE)
- ooharai, Grandinenia pallidissima ooharai A. Hunyadi & M. Szekeres, 2016 - (CLAUSILIIDAE)
- ooi, Hemiphaedusa ooi J.T. Kuroda, 1941 - (CLAUSILIIDAE)
- ooi, Gastrocopta ooi J.T. Kuroda, 1941 - (GASTROCOPTIDAE)
- ooi kosakai, Hemiphaedusa ooi kosakai J.T. Kuroda, 1941 - (CLAUSILIIDAE)
- ooides, Arcestes ooides Mojsisovics, 1875 † - (ARCESTIDAE) (FOSSIL)
- ooides, Pseudoliomesus ooides (A.T. von Middendorff, 1848) - (BUCCINIDAE)
- ooides bistriatus, Pseudoliomesus ooides bistriatus W.H. Dall, 1907 - syn of: Pseudoliomesus nux bistriatus (W.H. Dall, 1907) - (BUCCINIDAE)
- ooides canaliculatus, Pseudoliomesus ooides canaliculatus (W.H. Dall, 1874) - syn of: Pseudoliomesus canaliculatus (W.H. Dall, 1874) - (BUCCINIDAE)
- ookuboi, Atractophaedusa ookuboi H. Nordsieck, 2005 - (CLAUSILIIDAE)
- ookuboi, Serriphaedusa ookuboi H. Nordsieck, 2007 - (CLAUSILIIDAE)
- ookuboi, Grandinenia ookuboi H. Nordsieck, 2005 - (CLAUSILIIDAE)
- ookuboi, Acanthophaedusa ookuboi H. Nordsieck, 2007 - (CLAUSILIIDAE)
- ookuboi, Metaphaedusa pallidocincta ookuboi H. Nordsieck, 2005 - (CLAUSILIIDAE)
- ookuboi pulchricosta, Grandinenia ookuboi pulchricosta H. Nordsieck, 2007 - (CLAUSILIIDAE)
- oolitensis, Rissoina oolitensis Faber, 2017 † - (RISSOINIDAE) (FOSSIL)
- oolitharum, Astarte oolitharum A.E.M. Cossmann, 1925 † - (ASTARTIDAE) (FOSSIL)
- oolithica, Sphaeriola oolithica (Rollier †) - (LUCINIDAE) (FOSSIL)
- oolithica, Rostellaria oolithica Buvignier, 1843 † - syn of: Quadrinervus oolithicus (Buvignier, 1843 †) - (ROSTELLARIIDAE) (FOSSIL)
- oolithicum, Lissoceras oolithicum (A.V.M.D. D'Orbigny, 1842 †) - (HAPLOCERATIDAE) (FOSSIL)
- oolithicus, Quadrinervus oolithicus (Buvignier, 1843 †) - (APORRHAIDAE) (FOSSIL)
- oolitica, Chilodontoidea oolitica W.H. Hudleston, 1896 † - (CHILODONTIDAE) (FOSSIL)
- Oolitica, syn of: Genus Ooliticia Hyatt, 1889 † (EUCYCLIDAE) (FOSSIL)
- oolitica, Pholas oolitica J. Morris & J. Lycett, 1855 † - syn of: Girardotia costellata (J. Morris & J. Lycett, 1855 †) - (PHOLADIDAE) (FOSSIL)
- oolitica, Regalilima oolitica (J. Lycett, 1857 †) - (PTERIOIDEA (UNASSIGNED)) (FOSSIL)
- Ooliticia, Genus Ooliticia Hyatt, 1889 † (EUCYCLIDAE) (FOSSIL)
- oomedusae, Chama oomedusae A. Matsukuma, 1996 - (CHAMIDAE)
- oomorpha, Achatinella bulimoides oomorpha J.T. Gulick, 1858 - (ACHATINELLIDAE)
- oomorpha, Melanopsis oomorpha C. De Stefani, 1877 † - syn of: Melanopsis affinis A.E.J. Férussac, 1819 † - (MELANOPSIDAE) (FOSSIL)
- oomorphus, Phoenicobius oomorphus (G.B. I Sowerby, 1841) - (BRADYBAENIDAE)
- oomorphus amatangana, Phoenicobius oomorphus amatangana M. Smith, 1932 - syn of: Phoenicobius aratus amatanganus (M. Smith, 1932) - (BRADYBAENIDAE)
- oomurai, Neptunea oomurai Y. Otuka, 1940 † - (BUCCINIDAE) (FOSSIL)
- Oonendoceras, Genus Oonendoceras Chen & Qi, 1982 † (YANHECERIDA (UNASSIGNED)) (FOSSIL)
- Oonia, Subgenus Pseudomelania (Oonia) Gemmellaro, 1878 † (PSEUDOMELANIIDAE) (FOSSIL)
- oonisca, Odostomia oonisca W.H. Dall & P. Bartsch, 1909 - (PYRAMIDELLIDAE)
- Oonoceras, Genus Oonoceras Hyatt, 1884 † (OONOCERATIDAE) (FOSSIL)
- OONOCERATIDAE Hyatt, 1884 † - Family (CEPHALOPODA-NAUTILOIDEA [Subclass]-ONCOCERIDA [Order]) (FOSSIL)
- oonogai, Mya arenaria oonogai J. Makiyama, 1935 - (MYIDAE)
- Oopecten, Subgenus Pecten (Oopecten) Schlotheim, 1813 † (PECTINIDAE) (FOSSIL)
- Oopelta, Genus Oopelta O.A.L. Mörch, 1867 (OOPELTIDAE)
- OOPELTIDAE Cockerell, 1891 - Family (GASTROPODA-HETEROBRANCHIA [Subclass]-PULMONATA [Infraclass]-STYLOMMATOPHORA [Order]-ARIONOIDEA [Superfamily])
- Oophaedusa, Subgenus Luchuphaedusa (Oophaedusa) H.A. Pilsbry, 1905 (CLAUSILIIDAE)
- Oophaedusa, syn of: Genus Luchuphaedusa H.A. Pilsbry, 1905 (CLAUSILIIDAE)
- oophaga, Calliopaea oophaga H.M. Lemche in T. Gascoigne & Sartory, 1974 - (LIMAPONTIIDAE)
- oophaga, Acesta oophaga Järnegren, C.F.C. Schander & A.T. Young, 2007 - (LIMIDAE)
- Oophana, Genus Oophana C.M.F. Ancey, 1884 (STREPTAXIDAE)
- Oopriamus, Subgenus Odostomia (Oopriamus) K.H.J. Thiele, 1930 (PYRAMIDELLIDAE)
- Oopyramis, Subgenus Tiberia (Oopyramis) K.H.J. Thiele, 1930 (PYRAMIDELLIDAE)
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pay
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put
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