Abietinaria Kirchenpauer, 1884 (additional source)
Ablennes hians (Valenciennes, 1846) (additional source)
Abudefduf sexfasciatus (Lacepède, 1801) (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)
Acanthosphaera Ehrenberg, 1858 (basis of record)
Acanthurus lineatus (Linnaeus, 1758) (additional source)
Acartia (Acartia) danae Giesbrecht, 1889 (basis of record)
Acartia (Acartia) negligens Dana, 1849 (basis of record)
Acartia (Acartiura) longiremis (Lilljeborg, 1853) (basis of record)
Achnanthes brevipes C.Agardh, 1824 (additional source)
Achnanthes delicatula (Kützing) Grunow in Cleve & Grunow, 1880 accepted as Planothidium delicatulum (Kützing) Round & Bukhtiyarova, 1996 accepted as Achnanthidium delicatulum f. delicatulum Kützing, 1844 (additional source)
Achnanthes hauckiana Grunow, 1880 (additional source)
Achnanthes longipes C.Agardh, 1824 (additional source)
Acrocalanus longicornis Giesbrecht, 1888 (additional source)
Acrochaetium humile (Rosenvinge) Børgesen, 1915 (additional source)
Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli, 1858 (additional source)
Actinocyclus normanii (Gregory) Hustedt, 1957 (additional source)
Actinoptychus splendens (Shadbolt) Ralfs ex Pritchard, 1861 (additional source)
Actinoptychus undulatus (J.W.Bailey) Ralfs, 1861 accepted as Actinoptychus senarius (Ehrenberg) Ehrenberg, 1843 accepted as Actinocyclus senarius Ehrenberg, 1838 (additional source)
Aegina citrea Eschscholtz, 1829 (additional source)
Aegisthus mucronatus Giesbrecht, 1891 (additional source)
Aequorea aequorea (Forsskål, 1775) accepted as Aequorea forskalea Péron & Lesueur, 1810 (additional source)
Aequorea coerulescens (Brandt, 1835) (additional source)
Aetea anguina (Linnaeus, 1758) (additional source)
Aetideopsis armata (Boeck, 1872) (additional source)
Aetideopsis multiserrata (Wolfenden, 1904) (additional source)
Aetideus armatus (Boeck, 1872) (additional source)
Aetideus bradyi Scott A., 1909 (basis of record)
Aetideus giesbrechti Cleve, 1904 (additional source)
Aetobatus narinari (Euphrasen, 1790) (additional source)
Aeverrillia setigera (Hincks, 1887) (additional source)
Agalma elegans (Sars, 1846) (additional source)
Alderia modesta (Lovén, 1844) (additional source)
Aldrovandia affinis (Günther, 1877) (additional source)
Alectis ciliaris (Bloch, 1787) (additional source)
Alepisaurus ferox Lowe, 1833 (additional source)
Alexandrium catenella (Whedon & Kofoid) Balech, 1985 (additional source)
Alopias superciliosus Lowe, 1841 (additional source)
Alopias vulpinus (Bonnaterre, 1788) (additional source)
Aluterus monoceros (Linnaeus, 1758) (additional source)
Aluterus scriptus (Osbeck, 1765) (additional source)
Amaeana trilobata (Sars, 1863) (additional source)
Amaroucium constellatum Verrill, 1871 accepted as Aplidium constellatum (Verrill, 1871) (additional source)
Ampharete acutifrons (Grube, 1860) (additional source)
Ampharete arctica Malmgren, 1866 accepted as Ampharete finmarchica (M. Sars, 1865) (additional source)
Amphibalanus amphitrite (Darwin, 1854) (additional source)
Amphibalanus eburneus (Gould, 1841) (additional source)
Amphibalanus improvisus (Darwin, 1854) (additional source)
Amphicaryon acaule Chun, 1888 (additional source)
Amphicteis gunneri (M. Sars, 1835) (additional source)
Amphidinium carterae Hulburt, 1957 (additional source)
Amphipholis squamata (Delle Chiaje, 1828) (additional source)
Amphiprora alata (Ehrenberg) Kützing, 1844 accepted as Entomoneis alata (Ehrenberg) Ehrenberg, 1845 (additional source)
Amphiprora paludosa var. paludosa W. Smith, 1853 accepted as Entomoneis paludosa (W.Smith) Reimer, 1975 (additional source)
Amphitrite cirrata Müller, 1776 (additional source)
Amphora laevis Gregory, 1857 (additional source)
Amphora ovalis (Kützing) Kützing, 1844 (additional source)
Amphora robusta Gregory, 1857 (additional source)
Ampithoe valida S.I. Smith, 1873 (additional source)
Anas acuta Linnaeus, 1758 (additional source)
Anas clypeata Linnaeus, 1758 accepted as Spatula clypeata (Linnaeus, 1758) (additional source)
Anas crecca Linnaeus, 1758 (additional source)
Anas penelope Linnaeus, 1758 accepted as Mareca penelope (Linnaeus, 1758) (additional source)
Anas platyrhynchos Linnaeus, 1758 (additional source)
Anas querquedula Linnaeus, 1758 accepted as Spatula querquedula (Linnaeus, 1758) (additional source)
Anas strepera Linnaeus, 1758 (additional source)
Ancistrosyllis groenlandica McIntosh, 1878 (additional source)
Anisomysis Hansen, 1910 (additional source)
Anonyx lilljeborgii Boeck, 1871 accepted as Anonyx lilljeborgi Boeck, 1871 (additional source)
Anser albifrons (Scopoli, 1769) (additional source)
Antennarius striatus (Shaw, 1794) (additional source)
Anthomastus Verrill, 1878 (additional source)
Anthoptilum grandiflorum (Verrill, 1879) (additional source)
Antigonia capros Lowe, 1843 (additional source)
Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (additional source)
Apogon cookii MacLeay, 1881 accepted as Ostorhinchus cookii (MacLeay, 1881) (additional source)
Arabella (Arabella) iricolor (Montagu, 1804) accepted as Arabella iricolor (Montagu, 1804) (additional source)
Arabella mutans (Chamberlin, 1919) (additional source)
Archescolecithrix auropecten (Giesbrecht, 1893) (additional source)
Arcocellulus cornucervis G.R.Hasle, H.A.von Stosch & E.E.Syvertsen, 1983 (additional source)
Arcoscalpellum michelottianum (Seguenza, 1876) (additional source)
Arctonula arctica (M. Sars, 1851) (additional source)
Arenaria interpres (Linnaeus, 1758) (additional source)
Arenicola brasiliensis Nonato, 1958 (additional source)
Argyropelecus aculeatus Valenciennes, 1850 (additional source)
Argyropelecus affinis Garman, 1899 (additional source)
Argyropelecus gigas Norman, 1930 (additional source)
Argyropelecus hemigymnus Cocco, 1829 (additional source)
Argyropelecus sladeni Regan, 1908 (additional source)
Aricidea nolani Webster & Benedict, 1887 (additional source)
Aricidea quadrilobata Webster & Benedict, 1887 represented as Aricidea (Strelzovia) quadrilobata Webster & Benedict, 1887 (additional source)
Arietellus giesbrechti Sars G.O., 1905 (additional source)
Arietellus plumifer Sars G.O., 1905 (additional source)
Arietellus setosus Giesbrecht, 1893 (additional source)
Arietellus simplex Sars G.O., 1905 (additional source)
Aristaeomorpha foliacea (Risso, 1827) (additional source)
Aristaeopsis edwardsiana (Johnson, 1868) (additional source)