Abietinella Levinsen, 1913 (extant flag source)
Abietinella Levinsen, 1913 (basis of record)
Abyssopathes Opresko, 2002 (basis of record)
Abyssopathes Opresko, 2002 (extant flag source)
Acanthopathes Opresko, 2004 (extant flag source)
Acanthopathes Opresko, 2004 (basis of record)
Acanthoprimnoa Cairns & Bayer, 2004 (basis of record)
Acanthoprimnoa Cairns & Bayer, 2004 (extant flag source)
Acauloides Bouillon, 1965 (basis of record)
Acauloides Bouillon, 1965 (extant flag source)
Acrozoanthus Saville-Kent, 1893 (basis of record)
Acrozoanthus Saville-Kent, 1893 (extant flag source)
Agalmatidae Brandt, 1834 (extant flag source)
Agalmatidae Brandt, 1834 (basis of record)
Agglutinaria Antsulevich, 1987 (basis of record)
Agglutinaria Antsulevich, 1987 (extant flag source)
Aglaopheniidae Broch, 1918 (extant flag source)
Aglaopheniidae Broch, 1918 (basis of record)
Agneziidae Monniot & Monniot, 1991 (basis of record)
Agneziidae Monniot & Monniot, 1991 (extant flag source)
Alaskagorgia Sánchez & Cairns, 2004 (basis of record)
Alaskagorgia Sánchez & Cairns, 2004 (extant flag source)
Alaysiidae accepted as Siboglinidae Caullery, 1914 (basis of record)
Alaysiidae accepted as Siboglinidae Caullery, 1914 (extant flag source)
Alcyonidae accepted as Alcyoniidae Lamouroux, 1812 (basis of record)
Allorathkea Schmidt, 1972 (basis of record)
Allorathkea Schmidt, 1972 (extant flag source)
Altairina Vargas-Hernandez & Ochoa-Figuera, 1991 accepted as Corymorpha M. Sars, 1835 (extant flag source)
Altairina Vargas-Hernandez & Ochoa-Figuera, 1991 accepted as Corymorpha M. Sars, 1835 (basis of record)
Amaroucium Milne Edwards, 1841 accepted as Aplidium Savigny, 1816 (basis of record)
Amaroucium Milne Edwards, 1841 accepted as Aplidium Savigny, 1816 (extant flag source)
Amphibelemnon Lopez-Gonzalez, Gili & Williams, 2000 (basis of record)
Amphibelemnon Lopez-Gonzalez, Gili & Williams, 2000 (extant flag source)
Amphicarpa Michaelsen, 1922 (basis of record)
Amphicarpa Michaelsen, 1922 (extant flag source)
Amplexidiscus Dunn & Hamner, 1980 (extant flag source)
Amplexidiscus Dunn & Hamner, 1980 (basis of record)
Anadistoma Kott, 1992 (extant flag source)
Anadistoma Kott, 1992 (basis of record)
Anarthroclada Naumov, 1955 (extant flag source)
Anarthroclada Naumov, 1955 (basis of record)
Andvakiidae Danielssen, 1890 (basis of record)
Andvakiidae Danielssen, 1890 (extant flag source)
Anisopus accepted as Sericosura Fry & Hedgpeth, 1969 (basis of record)
Annisis Alderslade, 1998 (basis of record)
Annisis Alderslade, 1998 (extant flag source)
Antarctoscyphus Peña-Cantero, García-Carrascosa & Vervoort, 1997 (extant flag source)
Antarctoscyphus Peña-Cantero, García-Carrascosa & Vervoort, 1997 (basis of record)
Antennellopsis Jäderholm, 1896 (basis of record)
Antennellopsis Jäderholm, 1896 (extant flag source)
Anthohebella Boero, Bouillon & Kubota, 1997 (basis of record)
Anthohebella Boero, Bouillon & Kubota, 1997 (extant flag source)
Anthohydra Salvini Plawen & Chandrasekhara Rao, 1973 accepted as Eugymnanthea Palombi, 1936 (extant flag source)
Anthohydra Salvini Plawen & Chandrasekhara Rao, 1973 accepted as Eugymnanthea Palombi, 1936 (basis of record)
Antigomonidae accepted as Antygomonidae Adrianov & Malakhov, 1994 (basis of record)
Antigomonidae accepted as Antygomonidae Adrianov & Malakhov, 1994 (extant flag source)
Antipathes Pallas, 1766 (basis of record)
Antipathes Pallas, 1766 (extant flag source)
Antipathidae Ehrenberg, 1834 (basis of record)
Antygomonas Nebelsick, 1990 (basis of record)
Antygomonas Nebelsick, 1990 (extant flag source)
Antygomonidae Adrianov & Malakhov, 1994 (extant flag source)
Antygomonidae Adrianov & Malakhov, 1994 (basis of record)
Apanipathes (basis of record)
Apanipathes (extant flag source)
Apanipathes (current name source)
Aphanipathidae Opresko, 2004 (extant flag source)
Aphanipathidae Opresko, 2004 (basis of record)
Aplidium Savigny, 1816 (extant flag source)
Aplidium Savigny, 1816 (basis of record)
Appendicularia Fol, 1874 (basis of record)
Appendicularia Fol, 1874 (extant flag source)
Arachnacthidae McMurrich, 1910 accepted as Arachnactidae McMurrich, 1910 (basis of record)
Archdistoma accepted as Archidistoma Garstang, 1891 (basis of record)
Archdistoma accepted as Archidistoma Garstang, 1891 (extant flag source)
Archiascidia Julin, 1904 accepted as Pycnoclavella Garstang, 1891 (basis of record)
Archiascidia Julin, 1904 accepted as Pycnoclavella Garstang, 1891 (extant flag source)
Arcovestiidae accepted as Siboglinidae Caullery, 1914 (extant flag source)
Arcovestiidae accepted as Siboglinidae Caullery, 1914 (basis of record)
Arenodiplosoma Menker & Ax, 1970 accepted as Diplosoma Macdonald, 1859 (extant flag source)
Arenodiplosoma Menker & Ax, 1970 accepted as Diplosoma Macdonald, 1859 (basis of record)
Armorhydridae Swedmark & Teissier, 1958 (basis of record)
Armorhydridae Swedmark & Teissier, 1958 (extant flag source)
Armorloricus Kristensen & Gad, 2004 (extant flag source)
Armorloricus Kristensen & Gad, 2004 (basis of record)
Arnbackia Brewin, 1950 (basis of record)
Arnbackia Brewin, 1950 (extant flag source)
Arntzia López-González, Gili & Orejas, 2002 (extant flag source)
Arntzia López-González, Gili & Orejas, 2002 (basis of record)
Ascidiopsis Verrill, 1872 accepted as Ascidia Linnaeus, 1767 (basis of record)
Ascidiopsis Verrill, 1872 accepted as Ascidia Linnaeus, 1767 (extant flag source)
Ascolepis Thomson & Rennet, 1931 accepted as Fannyella Gray, 1872 (extant flag source)
Ascolepis Thomson & Rennet, 1931 accepted as Fannyella Gray, 1872 (basis of record)
Assymetron Kirkaldy, 1895 accepted as Asymmetron Andrews, 1893 (extant flag source)
Assymetron Kirkaldy, 1895 accepted as Asymmetron Andrews, 1893 (basis of record)
Asteriopathes Opresko, 2004 (extant flag source)
Asteriopathes Opresko, 2004 (basis of record)
Astrohydra Hashimoto, 1981 (basis of record)
Astrohydra Hashimoto, 1981 (extant flag source)
Astroides Quoy & Gaimard, 1827 (basis of record)