• "Lower Heterobranchia"
• [non-Uristidae] (temporary name)
• [non-Uristidae] albinus (K.H. Barnard, 1932) (temporary name)
• [non-Uristidae] georgianus (Schellenberg, 1931) (temporary name)
• [unassigned] Caenogastropoda (temporary name)
• [unassigned] Cardiidae (temporary name)
• [unassigned] Cladobranchia (temporary name)
• [unassigned] Decapodiformes (temporary name)
• [unassigned] Euheterodonta (temporary name)
• [unassigned] Heterobranchia (temporary name)
• [unassigned] Neogastropoda (temporary name)
• [unassigned] Seguenzioidea (temporary name)
• [unassigned] Solenogastres (temporary name)
• [unassigned] Trochidae (temporary name)
• [unassigned] Vetigastropoda (temporary name)
• [unassigned] Pectinidae (temporary name)
• Aaptos Gray, 1867
• Abarenicola Wells, 1959
• Abarenicola affinis (Ashworth, 1903)
• Abarenicola affinis affinis (Ashworth, 1902) represented as Abarenicola affinis (Ashworth, 1903)
• Abarenicola assimilis (Ehlers, 1897)
• Abarenicola assimilis assimilis (Ehlers, 1897) accepted as Abarenicola assimilis (Ehlers, 1897)
• Abatus Troschel, 1851
• Abatus (Pseudabatus) Koehler, 1911
• Abatus (Pseudabatus) nimrodi (Koehler, 1911)
• Abatus agassizii Mortensen, 1910
• Abatus beatriceae (Larrain, 1986)
• Abatus bidens Mortensen, 1910 accepted as Abatus cavernosus bidens Mortensen, 1910
• Abatus cavernosus (Philippi, 1845)
• Abatus cavernosus bidens Mortensen, 1910
• Abatus cordatus (Verrill, 1876)
• Abatus curvidens Mortensen, 1936
• Abatus elongatus (Koehler, 1908) accepted as Abatus koehleri (Thiéry, 1909)
• Abatus ingens Koehler, 1926
• Abatus koehleri (Thiéry, 1909)
• Abatus nimrodi (Koehler, 1911) accepted as Pseudabatus nimrodi Koehler, 1911 accepted as Abatus (Pseudabatus) nimrodi (Koehler, 1911)
• Abatus philippi Lovén, 1871 accepted as Abatus philippii Lovén, 1871
• Abatus philippii Lovén, 1871
• Abatus shackletoni Koehler, 1911
• Abietinaria Kirchenpauer, 1884
• Abietinaria abietina (Linnaeus, 1758)
• Abietinella Levinsen, 1913
• Abietinella operculata (Jäderholm, 1903)
• Abraliopsis Joubin, 1896
• Abraliopsis (Micrabralia) Pfeffer, 1900
• Abraliopsis (Micrabralia) gilchristi Robson, 1924
• Abraliopsis gilchristi (Robson, 1924) represented as Abraliopsis (Micrabralia) gilchristi Robson, 1924
• Abylidae L. Agassiz, 1862
• Abylopsinae Totton, 1954
• Abyssaster Madsen, 1961
• Abyssaster diadematus (Sladen, 1883)
• Abyssaster planus (Sladen, 1883)
• Abyssochrysoidea Tomlin, 1927
• Abyssoclymene Hartman, 1967
• Abyssoclymene annularis Hartman, 1967
• Abyssocucumis Heding, 1942
• Abyssocucumis abyssorum (Théel, 1886)
• Abyssocucumis liouvillei (Vaney, 1914) Gutt, 1988 accepted as Staurocucumis liouvillei (Vaney, 1914) Ekman, 1927
• Abyssocucumis tourqueti (Vaney, 1906) accepted as Staurocucumis turqueti (Vaney, 1906)
• Abyssocypris Bold, 1974
• Abyssocypris atlantica (Maddocks, 1977)
• Abyssocythere Benson, 1971
• Abyssocythere antarctica (Neale, 1967) accepted as Austrotrachyleberis antarctica (Neale, 1967)
• Abyssocythere bensoni Brandão, Stuhlmann, Vital & Brandt, 2016
• Abyssogyra A. H. Clarke, 1961 accepted as Moelleriopsis Bush, 1897
• Abyssogyra vemae Clarke, 1961 accepted as Moelleriopsis vemae (Clarke, 1961)
• Abyssoninoe Orensanz, 1990
• Abyssoninoe abyssorum (McIntosh, 1885)
• Abyssophilos Jellinek & Swanson, 2003
• Abyssophilos ktis Jellinek & Swanson, 2003
• Abyssorchomene De Broyer, 1984
• Abyssorchomene charcoti (Chevreux, 1912)
• Abyssorchomene nodimanus (Walker, 1903)
• Abyssorchomene plebs (Hurley, 1965) represented as Pseudorchomene plebs (Hurley, 1965)
• Abyssorchomene rossi (Walker, 1903) represented as Pseudorchomene rossi (Walker, 1903)
• Abyssorchomene scotianensis (Andres, 1983)
• Abyssorhynchia Zezina, 1980
• Abyssorhynchia craneana (Dall, 1895)
• Abyssothyris Thomson, 1927
• Abyssothyris wyvillei (Davidson, 1878)
• Abyssotrophon Egorov, 1993
• Abyssotrophon drygalskii (Thiele, 1912) accepted as Trophon drygalskii Thiele, 1912
• Acanthamunnopsis Schultz, 1978
• Acanthamunnopsis hystrix Schultz, 1978
• Acantharcturus Schultz, 1981
• Acantharcturus acanthurus (Monod, 1925) accepted as Mixarcturus acanthurus (Monod, 1925)
• Acantharcturus acutipleon Schultz, 1981
• Acanthascinae Schulze, 1897
• Acanthascus Schulze, 1886
• Acanthascus (Rhabdocalyptus) Schulze, 1886 accepted as Rhabdocalyptus Schulze, 1886
• Acanthascus (Rhabdocalyptus) australis (Topsent, 1901) accepted as Rhabdocalyptus australis Topsent, 1901
• Acanthaspidia Stebbing, 1893 accepted as Iolanthe Beddard, 1886
• Acanthaspidia acanthonotus (Beddard, 1886) accepted as Iolanthe acanthonotus Beddard, 1886
• Acanthaspidia drygalskii Vanhöffen, 1914 accepted as Iolanthe drygalskii (Vanhöffen, 1914)
• Acanthaspidia iolanthoidea Vasina & Kussakin, 1982 accepted as Iolanthe iolanthoidea (Vasina & Kussakin, 1982)
• Acanthaspidia longiramosa Vasina & Kussakin, 1982 accepted as Iolanthe longiramosa (Vasina & Kussakin, 1982)
• Acanthaspidia mucronata (Menzies & Schultz, 1968) accepted as Iolanthe mucronata (Menzies & Schultz, 1968)
• Acanthaspidia pleuronotus (Menzies & Schultz, 1968) accepted as Iolanthe pleuronotus Menzies & Schultz, 1968
• Acanthaspidia porrecta Menzies & Schultz, 1968 accepted as Iolanthe porrecta (Menzies & Schultz, 1968)
• Acanthaspidia rostrata (Menzies & Schultz, 1968) accepted as Iolanthe rostrata (Menzies & Schultz, 1968)