Abyssocucumis Heding, 1942 (basis of record)
Abyssocucumis abyssorum (Théel, 1886) (basis of record)
Acanthotrochus Danielssen & Koren, 1881 (basis of record)
Acanthotrochus mirabilis Danielssen & Koren, 1881 (basis of record)
Aceste Thomson, 1877 (basis of record)
Aceste bellidifera Thomson, 1877 (basis of record)
Achiridota H.L. Clark, 1908 (basis of record)
Achiridota profunda Heding, 1935 (basis of record)
Achlyonice Théel, 1879 (basis of record)
Achlyonice myriamae Gebruk, 1997 (basis of record)
Aeropsidae Lambert, 1896 (basis of record)
Aeropsis Mortensen, 1907 (basis of record)
Aeropsis rostrata (Norman, 1876) (basis of record)
Allantis Hérouard, 1902 accepted as Mesothuria Ludwig, 1894 (basis of record)
Amperima Pawson, 1965 (basis of record)
Amperima furcata (Hérouard, 1899) (basis of record)
Amperima rosea (E. Perrier, 1886) (basis of record)
Amphidetus L. Agassiz, 1836 accepted as Echinocardium Gray, 1825 (basis of record)
Amphilepididae Matsumoto, 1915 (basis of record)
Amphilepis Ljungman, 1867 (basis of record)
Amphilepis ingolfiana Mortensen, 1933 (basis of record)
Amphilepis norvegica (Ljungman, 1865) (basis of record)
Amphiophiura Matsumoto, 1915 (basis of record)
Amphiophiura bullata (Thomson, 1877) (basis of record)
Amphiophiura bullata vitjazi Litvinova, 1971 (basis of record)
Amphioplus Verrill, 1899 (basis of record)
Amphioplus (Amphichilus) Matsumoto, 1917 (basis of record)
Amphipholis Ljungman, 1866 (basis of record)
Amphipholis murmanica Djakonov, 1929 (basis of record)
Amphipholis squamata (Delle Chiaje, 1828) (basis of record)
Amphipholis torelli Ljungman, 1872 (basis of record)
Amphiura Forbes, 1843 (basis of record)
Amphiura (Amphiura) grandisquama Lyman, 1869 (basis of record)
Amphiura (Ophiopeltis) Düben & Koren, 1846 (basis of record)
Amphiura (Ophiopeltis) securigera (Düben & Koren, 1846) (basis of record)
Amphiura abyssorum Norman in Jeffreys, 1876 (basis of record)
Amphiura bellis Lyman, 1879 (basis of record)
Amphiura borealis (G.O. Sars, 1872) (basis of record)
Amphiura cherbonnieri Guille, 1972 (basis of record)
Amphiura chiajei Forbes, 1843 (basis of record)
Amphiura delamarei Cherbonnier, 1958 (basis of record)
Amphiura filiformis (O.F. Müller, 1776) (basis of record)
Amphiura fragilis Verrill, 1885 (basis of record)
Amphiura griegi Mortensen, 1920 (basis of record)
Amphiura incana Lyman, 1879 represented as Amphiura (Amphiura) incana Lyman, 1879 (basis of record)
Amphiura mediterranea Lyman, 1882 (basis of record)
Amphiura otteri Ljungman, 1872 (basis of record)
Amphiura palmeri Lyman, 1882 (basis of record)
Amphiura richardi Koehler, 1896 (basis of record)
Amphiura sarsi Ljungman, 1872 (basis of record)
Amphiura senegalensis Madsen, 1970 (basis of record)
Amphiura stepanovi Djakonov, 1954 (basis of record)
Amphiura sundevalli (Müller & Troschel, 1842) (basis of record)
Amphiuridae Ljungman, 1867 (basis of record)
Anseropoda Nardo, 1834 (basis of record)
Anseropoda lobiancoi (Ludwig, 1897) (basis of record)
Anseropoda placenta (Pennant, 1777) (basis of record)
Antedon de Fréminville, 1811 (additional source)
Antedon bifida (Pennant, 1777) (additional source)
Antedon duebenii Böhlsche, 1866 (additional source)
Antedon mediterranea (Lamarck, 1816) (additional source)
Antedon petasus (Düben & Koren, 1846) (additional source)
Antedonidae Norman, 1865 (additional source)
Anthophiura H.L. Clark, 1911 (basis of record)
Anthophiura ingolfi Fasmer, 1930 (basis of record)
Apodida (basis of record)
Araeosoma Mortensen, 1903 (basis of record)
Araeosoma violaceum Mortensen, 1903 (basis of record)
Arbacia Gray, 1835 (additional source)
Arbacia lixula (Linnaeus, 1758) (basis of record)
Arbaciella Mortensen, 1910 (basis of record)
Arbaciella elegans Mortensen, 1910 (basis of record)
Arbaciidae Gray, 1855 (basis of record)
Arbacina Pomel, 1869 † accepted as Genocidaris A. Agassiz, 1869 (basis of record)
Arbacioida (basis of record)
Archaster Müller & Troschel, 1840 (additional source)
Aslia Rowe, 1970 (basis of record)
Aslia lefevrei (Barrois, 1882) (basis of record)
Aspidodiadema A. Agassiz, 1879 (basis of record)
Aspidodiadema jacobyi A. Agassiz, 1880 (basis of record)
Aspidodiadematidae Duncan, 1889 (basis of record)
Aspidophiura Matsumoto, 1915 (basis of record)
Aspidophiura minuta (Lyman, 1878) (basis of record)
Asterias Linnaeus, 1758 (basis of record)
Asterias (Stolasterias) Sladen, 1889 accepted as Stolasterias Sladen, 1889 represented as Coscinasterias Verrill, 1867 (basis of record)
Asterias militaris O.F. Müller, 1776 accepted as Asteriscus militaris (O.F. Müller, 1776) accepted as Pteraster militaris (O.F. Müller, 1776) (basis of record)
Asterias panopla Stuxberg, 1879 accepted as Icasterias panopla (Stuxberg, 1879) (basis of record)
Asterias rubens Linnaeus, 1758 (basis of record)
Asteriidae Gray, 1840 (basis of record)
Asterina Nardo, 1834 (basis of record)
Asterina borealis Verrill, 1878 accepted as Poraniomorpha (Poraniomorpha) hispida (M. Sars, 1872) (basis of record)
Asterina gibbosa (Pennant, 1777) (basis of record)
Asterina pancerii (Gasco, 1876) (basis of record)
Asterina phylactica Emson & Crump, 1979 (basis of record)
Asterinidae Gray, 1840 (basis of record)
Asterinides Verrill, 1913 (basis of record)
Asteriscus Müller & Troschel, 1842 accepted as Anseropoda Nardo, 1834 (basis of record)
Asteroidea (basis of record)
Asteronychidae Ljungman, 1867 (basis of record)
Asteronyx Müller & Troschel, 1842 (basis of record)