Abalistes stellatus (Anonymous, 1798) (additional source)
Abietinaria Kirchenpauer, 1884 (additional source)
Ablennes hians (Valenciennes, 1846) (additional source)
Abra maxima (G. B. Sowerby III, 1894) accepted as Abra philippinensis (E. A. Smith, 1885) (additional source)
Abra profundorum japonicum Okutani, 1975 accepted as Abra profundorum (E. A. Smith, 1885) (additional source)
Abralia andamanica E. S. Goodrich, 1896 (additional source)
Abraliopsis lineata (E. S. Goodrich, 1896) (additional source)
Abyla schmidti Sears, 1953 accepted as Abyla trigona Quoy & Gaimard, 1827 (additional source)
Abyla trigona Quoy & Gaimard, 1827 (additional source)
Abylopsis tetragona (Otto, 1823) (additional source)
Acanthacaris tenuimana Spence Bate, 1888 (additional source)
Acanthaphritis grandisquamis Günther, 1880 (additional source)
Acanthella Schmidt, 1862 (additional source)
Acanthephyra armata A. Milne-Edwards, 1881 (additional source)
Acanthephyra carinata Spence Bate, 1888 (additional source)
Acanthephyra curtirostris Wood-Mason in Wood-Mason & Alcock, 1891 (additional source)
Acanthephyra eximia Smith, 1884 (additional source)
Acanthephyra purpurea A. Milne-Edwards, 1881 (additional source)
Acanthocybium solandri (Cuvier, 1832) (additional source)
Acanthogorgia armata Verrill, 1878 (additional source)
Acanthogorgia aspera Pourtalès, 1867 (additional source)
Acanthonchus (Acanthonchus) setoi Wieser, 1955 (additional source)
Acanthoscina acanthodes (Stebbing, 1895) (additional source)
Acanthosphaera Ehrenberg, 1858 (basis of record)
Acanthosphaera actinota Haeckel, 1860 (basis of record)
Acanthosphaera dodecastyla Mast, 1910 (basis of record)
Acanthosquilla multifasciata (Wood-Mason, 1895) (additional source)
Acanthurus lineatus (Linnaeus, 1758) (additional source)
Acanthurus maculiceps (Ahl, 1923) (additional source)
Acanthurus pyroferus Kittlitz, 1834 (additional source)
Acartia (Acartia) danae Giesbrecht, 1889 (basis of record)
Acartia (Acartia) negligens Dana, 1849-1852 (basis of record)
Acartia (Acartiura) longiremis (Lilljeborg, 1853) (basis of record)
Acartia (Odontacartia) erythraea Giesbrecht, 1889 represented as Acartia (Odontacartia) erythraea erythraea Giesbrecht, 1889 (basis of record)
Acaudina molpadioides (Semper, 1867) (basis of record)
Acharax johnsoni (Dall, 1891) (additional source)
Acoetes flagelliformis (Wesenberg-Lund, 1949) (additional source)
Acreuciroa rostrata (Jaeckel & Thiele, 1931) accepted as Euciroa rostrata Jaeckel & Thiele, 1931 (additional source)
Acrocalanus andersoni Bowman, 1958 (additional source)
Acrocalanus gibber Giesbrecht, 1888 (additional source)
Acrocalanus gracilis Giesbrecht, 1888 (additional source)
Acrocalanus longicornis Giesbrecht, 1888 (additional source)
Acrocalanus monachus Giesbrecht, 1888 (additional source)
Acropoma japonicum Günther, 1859 (additional source)
Acropora tenuis (Dana, 1846) (additional source)
Acrosphaera lappacea (Haeckel) Johnson & Nigrini, 1980 (basis of record)
Acrosphaera murrayana (Haeckel) Hilmers, 1906 (basis of record)
Acrosphaera spinosa Caulet, 1986 (basis of record)
Acryptolaria conferta (Allman, 1877) (additional source)
Acryptolaria crassicaulis (Allman, 1888) (additional source)
Actinocyclus curvatulus Janisch, 1874 (additional source)
Actinocyclus ingens Rattray, 1890 † (additional source)
Actinomma antarcticum (Haeckel) Nigrini, 1967 (additional source)
Actinomma arcadophorum Haeckel, 1887 (additional source)
Actinomma leptodermum (Jorgensen) Nigrini & Moore, 1979 (additional source)
Actinomma medianum Nigrini, 1967 (additional source)
Adeonellopsis coscinophora (Reuss, 1848) (additional source)
Adercotryma glomeratum (Brady, 1878) (additional source)
Aega falcata Kensley & Chan, 2001 (additional source)
Aegaeon lacazei (Gourret, 1887) (additional source)
Aegaeon rathbuni De Man, 1918 (additional source)
Aegina citrea Eschscholtz, 1829 (additional source)
Aeginura grimaldii Maas, 1904 (additional source)
Aegisthus mucronatus Giesbrecht, 1891 (additional source)
Aequorea aequorea (Forsskål, 1775) accepted as Aequorea forskalea Péron & Lesueur, 1810 (additional source)
Aequorea macrodactyla (Brandt, 1835) (additional source)
Aequorea pensilis (Haeckel, 1879) (additional source)
Aetideopsis armata (Boeck, 1873) (additional source)
Aetideopsis multiserrata (Wolfenden, 1904) (additional source)
Aetideus acutus Farran, 1929 (additional source)
Aetideus armatus (Boeck, 1873) (additional source)
Aetideus bradyi Scott A., 1909 (basis of record)
Aetideus giesbrechti Cleve, 1904 (additional source)
Agalma elegans (M. Sars, 1846) (additional source)
Aglaophamus macroura (Schmarda, 1861) (additional source)
Aglaophenia Lamouroux, 1812 (additional source)
Aglaura hemistoma Péron & Lesueur, 1810 (additional source)
Agononida incerta (Henderson, 1888) (additional source)
Aidanosagitta neglecta (Aida, 1897) (additional source)
Aidanosagitta regularis (Aida, 1897) (additional source)
Alcanivorax dieselolei Liu & Shao, 2005 (additional source)
Alcyonidium mytili Dalyell, 1848 accepted as Alcyonidioides mytili (Dalyell, 1848) (additional source)
Aldrovandia affinis (Günther, 1877) (additional source)
Alectis ciliaris (Bloch, 1787) (additional source)
Alepisaurus ferox Lowe, 1833 (additional source)
Alepocephalus bicolor Alcock, 1891 (additional source)
Alepocephalus longiceps Lloyd, 1909 (additional source)
Alepocephalus longirostris Okamura & Kawanishi, 1984 (additional source)
Alepocephalus owstoni Tanaka, 1908 (additional source)
Alepocephalus triangularis Okamura & Kawanishi, 1984 (additional source)
Alepocephalus umbriceps Jordan & Thompson, 1914 (additional source)
Alliatina nitida (Millett, 1900) (additional source)
Alopias superciliosus Lowe, 1841 (additional source)
Alopias vulpinus (Bonnaterre, 1788) (additional source)
Alpheus macroskeles Alcock & Anderson, 1899 (additional source)
Alteromonas Baumann et al., 1972 (basis of record)
Altiverruca cristallina (Gruvel, 1907) (basis of record)
Altiverruca gibbosa (Hoek, 1883) (additional source)
Altiverruca nitida (Hoek, 1883) accepted as Gibbosaverruca nitida (Hoek, 1883) (additional source)
Aluterus monoceros (Linnaeus, 1758) (additional source)