• Abludomelita aculeata (Chevreux, 1911)
• Abludomelita gladiosa (Spence Bate & Westwood, 1862)
• Abludomelita obtusata (Montagu, 1813)
• Abludomelita richardi (Chevreux, 1900)
• Abyssorchomene abyssorum (Stebbing, 1888)
• Abyssorchomene chevreuxi (Stebbing, 1906)
• Abyssorchomene gerulicorbis (Shulenberger & Barnard, 1976)
• Acantharctus posteli (Forest, 1963)
• Acanthaspidia decorata (Hansen, 1895) accepted as Iolanthe decorata Hansen, 1895
• Acanthaspidia laevis Chardy, 1975 accepted as Iolanthe laevis (Chardy, 1975)
• Acanthaspidia typhlops (G. O. Sars, 1879) accepted as Iolanthe typhlops (G. O. Sars, 1879)
• Acanthephyra brevirostris Smith, 1885
• Acanthephyra curtirostris Wood-Mason in Wood-Mason & Alcock, 1891
• Acanthephyra eximea Smith, 1884 accepted as Acanthephyra eximia Smith, 1884
• Acanthephyra eximia Smith, 1884
• Acanthephyra pelagica (Risso, 1816)
• Acanthephyra purpurea A. Milne-Edwards, 1881
• Acanthephyra stylorostratis (Spence Bate, 1888)
• Acanthephyra tenuipes (Spence Bate, 1888)
• Acanthocarpus brevispinis Monod, 1946
• Acanthocope annulatus Menzies, 1962
• Acanthocope armata Chardy, 1972
• Acanthocope carinata Chardy, 1972
• Acanthomunna hystrix (Hansen, 1916)
• Acanthomysis longicornis (Milne Edwards, 1837)
• Acanthomysis strauchi (Czerniavsky, 1882) accepted as Paramysis (Metamysis) ullskyi Czerniavsky, 1882
• Acanthonotozoma cristatum (Ross, 1835)
• Acanthonotozoma inflatum (Krøyer, 1842)
• Acanthonotozoma magnum Just, 1978
• Acanthonotozoma monodentatum Kudrjaschov, 1965
• Acanthonotozoma rusanovae Bryazgin, 1974
• Acanthonotozoma serratum (O. Fabricius, 1780)
• Acanthonotozoma sinuatum Just, 1978
• Acanthonotus owenii Spence Bate, 1857 accepted as Epimeria cornigera (Fabricius, 1779) accepted as Epimeria (Epimeria) cornigera (Fabricius, 1779)
• Acanthonotus testudo White, 1850 accepted as Epimeria cornigera (Fabricius, 1779) accepted as Epimeria (Epimeria) cornigera (Fabricius, 1779)
• Acanthonyx brevifrons A. Milne-Edwards, 1869
• Acanthonyx lunulatus (Risso, 1816)
• Acanthoscina acanthodes (Stebbing, 1895)
• Acanthostepheia behringiensis (Lockington, 1877)
• Acanthostepheia incarinata Gurjanova, 1929
• Acanthostepheia malmgreni (Goës, 1866)
• Acanthozone cuspidata (Ross, 1835) sensu Stebbing, 1906 accepted as Paramphithoe hystrix (Ross, 1835)
• Aceroides (Aceroides) goesi Just, 1980
• Aceroides (Aceroides) latipes (G.O. Sars, 1883)
• Aceros phyllonyx (M. Sars, 1858) accepted as Arrhis phyllonyx (M. Sars, 1858)
• Achaeus cranchii Leach, 1817
• Achaeus gracilis (O.G. Costa, 1839)
• Achelous hastatus (Linnaeus, 1767)
• Achelous inaequalis (Miers, 1881)
• Acidostoma laticorne G.O. Sars, 1879
• Acidostoma laticornis G. O. Sars, 1879 accepted as Acidostoma laticorne G.O. Sars, 1879
• Acidostoma neglectum Dahl, 1964
• Acidostoma nodiferum Stephensen, 1923 accepted as Acidostoma obesum (Spence Bate & Westwood, 1861)
• Acidostoma obesum (Spence Bate & Westwood, 1861)
• Acidostoma sarsi Lincoln, 1979 accepted as Acidostoma nodiferum Stephensen, 1923 accepted as Acidostoma obesum (Spence Bate & Westwood, 1861)
• Acosta punctata (A. Costa in Hope, 1851)
• Acrobelione reverberii (Restivo, 1970)
• Aega affinis Milne Edwards, 1840
• Aega bicarinata Leach, 1818
• Aega crenulata Lutken, 1859
• Aega emarginata Leach, 1818 accepted as Aega psora (Linnaeus, 1758)
• Aega hirsuta Schioedte & Meinert, 1879
• Aega loveni Bovallius, 1886 accepted as Aegiochus ventrosa (M. Sars, 1859)
• Aega megalops Norman & Stebbing, 1886
• Aega microphthalma Dana, 1853
• Aega monophthalma Johnston, 1834
• Aega psora (Linnaeus, 1758)
• Aega rosacea (Risso, 1816) (uncertain > taxon inquirendum)
• Aega stroemii Lutken, 1859
• Aega tridens Leach, 1816
• Aega webbii (Guérin-Méneville, 1836)
• Aegaeon cataphracta (Olivi, 1792) accepted as Aegaeon cataphractus (Olivi, 1792)
• Aegaeon cataphractus (Olivi, 1792)
• Aegaeon lacazei (Gourret, 1887)
• Aegapheles deshaysiana (H. Milne Edwards, 1840)
• Aegina echinata Boeck, 1871 accepted as Aeginina longicornis (Krøyer, 1843)
• Aeginella spinosa Boeck, 1861
• Aeginina laevis (Boeck, 1861) accepted as Aeginina longicornis (Krøyer, 1843)
• Aeginina longicornis (Krøyer, 1843)
• Aeginina spinosissima (Stimpson, 1853) accepted as Aeginina longicornis (Krøyer, 1843)
• Aegiochus arctica (Lütken, 1859)
• Aegiochus gracilipes (Hansen, 1895)
• Aegiochus incisa (Schioedte & Meinert, 1879)
• Aegiochus nordenskioldii Bovallius, 1885 accepted as Aegiochus ventrosa (M. Sars, 1859)
• Aegiochus ventrosa (M. Sars, 1859)
• Africorchestia spinifera (Mateus, 1962)
• Afropinnotheres monodi Manning, 1993
• Afropisa carinimana (Miers, 1879)
• Afruca tangeri (Eydoux, 1835)
• Agathotanais ingolfi Hansen, 1913
• Akanthinotanais longipes (Hansen, 1913)
• Akanthinotanais similis (Sieg, 1977)
• Akanthophoreus gracilis (Krøyer, 1842)
• Akanthophoreus inermis (Hansen, 1913) accepted as Parakanthophoreus inermis (Hansen, 1913)
• Akanthophoreus longiremis (Lilljeborg, 1864) accepted as Parakanthophoreus longiremis (Lilljeborg, 1864)
• Akanthophoreus multiserratus (Hansen, 1913) accepted as Parakanthophoreus multiserratus (Hansen, 1913)
• Akerogammarus contiguus (Pjatakova, 1962)
• Akerogammarus knipowitschi Derzhavin & Pjatakova, 1967
• Alamprops profundus (Reyss, 1978)
• Alaotanais hastiger Norman & Stebbing, 1886 accepted as Neotanais hastiger (Norman & Stebbing, 1886)