Abrocomidae Miller & Gidley, 1918 (basis of record)
Abrocomophagidae Emerson & Price, 1976 (basis of record)
Abrocomophagidae Emerson & Price, 1976 (extant flag source)
Abylidae L. Agassiz, 1862 (basis of record)
Abylidae L. Agassiz, 1862 (extant flag source)
Abyssochrysidae Tomlin, 1927 (basis of record)
Abyssochrysidae Tomlin, 1927 (extant flag source)
Abyssochrysidae Tomlin, 1927 (habitat flag source)
Acalyptonotidae Walter, 1911 (basis of record)
Acalyptonotidae Walter, 1911 (extant flag source)
Acanaloniidae (basis of record)
Acanaloniidae (extant flag source)
Acanthaceae de Jussieu, 1789 (basis of record)
Acanthamoebidae Sawyer & Griffin, 1975 (basis of record)
Acanthamoebidae Sawyer & Griffin, 1975 (extant flag source)
Acantharia accepted as Acantharea (basis of record)
Acanthaspidiidae Menzies, 1962 (basis of record)
Acanthaspidiidae Menzies, 1962 (extant flag source)
Acanthasteridae Sladen, 1889 (basis of record)
Acanthobdellidae Livanow, 1905 (basis of record)
Acanthobdellidae Livanow, 1905 (extant flag source)
Acanthocephala (awaiting allocation) (habitat flag source)
Acanthochaetetidae Fischer, 1970 (basis of record)
Acanthocheilidae Wülker, 1929 accepted as Anisakidae Railliet & Henry, 1912 (basis of record)
Acanthocheilidae Wülker, 1929 accepted as Anisakidae Railliet & Henry, 1912 (extant flag source)
Acanthochiasmidae Haeckel, 1862 (basis of record)
Acanthochiasmidae Haeckel, 1862 (extant flag source)
Acanthochiasmidae Haeckel, 1862 (habitat flag source)
Acanthochitonidae Pilsbry, 1893 (basis of record)
Acanthocistidae accepted as Acanthocystidae Claus, 1874 (habitat flag source)
Acanthoclinidae Gunther, 1861 accepted as Plesiopidae Gunther, 1861 (basis of record)
Acanthoclinidae Gunther, 1861 accepted as Plesiopidae Gunther, 1861 (extant flag source)
Acanthoclinidae Gunther, 1861 accepted as Plesiopidae Gunther, 1861 (habitat flag source)
Acanthocnemidae Crowson, 1964 (basis of record)
Acanthocollaritrematidae (basis of record)
Acanthocollaritrematidae (extant flag source)
Acanthocollaritrematidae (habitat flag source)
Acanthocollidae Schewiakoff, 1926 (habitat flag source)
Acanthocolpidae Lühe, 1906 (basis of record)
Acanthocolpidae Lühe, 1906 (extant flag source)
Acanthocotylidae Price, 1936 (basis of record)
Acanthocotylidae Price, 1936 (extant flag source)
Acanthoctenidae Simon, 1892 accepted as Ctenidae Keyserling, 1877 (basis of record)
Acanthoctenidae Simon, 1892 accepted as Ctenidae Keyserling, 1877 (extant flag source)
Acanthocystidae Claus, 1874 (basis of record)
Acanthocystidae Claus, 1874 (extant flag source)
Acanthocystidae Claus, 1874 (habitat flag source)
Acanthoecidae Norris, 1965 (basis of record)
Acanthoecidae Norris, 1965 (extant flag source)
Acanthogammaridae Garjajewia, 1901 (basis of record)
Acanthogammaridae Garjajewia, 1901 (extant flag source)
Acanthogorgiidae Gray, 1859 (basis of record)
Acanthogorgiidae Gray, 1859 (extant flag source)
Acanthogorgiidae Gray, 1859 (habitat flag source)
Acanthomeniidae Salvini-Plawen, 1978 (basis of record)
Acanthomeniidae Salvini-Plawen, 1978 (extant flag source)
Acanthomeniidae Salvini-Plawen, 1978 (habitat flag source)
Acanthometridae Haeckel, 1887 (basis of record)
Acanthometridae Haeckel, 1887 (extant flag source)
Acanthonotozomatidae Stebbing, 1906 (basis of record)
Acanthonotozomatidae Stebbing, 1906 (extant flag source)
Acanthoplegmatidae accepted as Acanthoplegmidae Schewiakoff, 1926 (basis of record)
Acanthoplegmatidae accepted as Acanthoplegmidae Schewiakoff, 1926 (extant flag source)
Acanthoplegmatidae accepted as Acanthoplegmidae Schewiakoff, 1926 (habitat flag source)
Acanthoplegmidae Schewiakoff, 1926 (habitat flag source)
Acanthopteroctetidae Davis, 1978 (basis of record)
Acanthopteroctetidae Davis, 1978 (extant flag source)
Acanthosomatidae Signoret, 1864 (basis of record)
Acanthostomatidae (basis of record)
Acanthostomatidae (extant flag source)
Acanthothirididae † (habitat flag source)
Acanthuridae Bonaparte, 1835 (basis of record)
Acaridae Ewing & Nesbitt, 1942 (basis of record)
Acaronychidae Grandjean, 1932 (basis of record)
Acaronychidae Grandjean, 1932 (extant flag source)
Acarophenacidae Cross, 1965 (basis of record)
Acarophenacidae Cross, 1965 (extant flag source)
Acarpomyxa accepted as Tubulinea (basis of record)
Acartiidae G.O. Sars, 1903 (basis of record)
Acartiidae G.O. Sars, 1903 (extant flag source)
Acartophthalmidae Czerny, 1928 (basis of record)
Acaulidae Fraser, 1924 (basis of record)
Acaulidae Fraser, 1924 (extant flag source)
Acaulidae Fraser, 1924 (habitat flag source)
Acavidae Pilsbry, 1895 (basis of record)
Accacoeliidae Odhner, 1911 (basis of record)
Accacoeliidae Odhner, 1911 (extant flag source)
Accipitridae Viellot, 1816 (basis of record)
Aceraceae de Jussieu, 1789 accepted as Sapindaceae de Jussieu, 1789 (basis of record)
Acervulinidae Schultze, 1854 (basis of record)
Achariaceae Harms, 1897 (basis of record)
Achariaceae Harms, 1897 (extant flag source)
Achatinellidae Gulick, 1873 (basis of record)
Achatinidae Swainson, 1840 (basis of record)
Achatocarpaceae Heimerl, 1934 (basis of record)
Achatocarpaceae Heimerl, 1934 (extant flag source)
Achilidae Stål, 1866 (basis of record)
Achilixiidae (basis of record)
Achilixiidae (extant flag source)
Achillurbaniidae (basis of record)

 Habitat

 for Heteronemertea

Habitat: mostly marine, some freshwater and brackish (Parker). [details]

 Taxonomic remark

 for Aplysinellidae Bergquist, 1980

Misspelled ("Aplysellidae") in Parker, 1982 Classification section; correct spelling in text and Index. [details]

 Taxonomic remark

 for Cephalocarida

Treated as a subclass in Parker, 1982. [details]

 Taxonomic remark

 for Hormotrichopsis

Name listed in Silva, 1982 (= Chlorophyceae chapter of Parker, 1982), but untraced elsewhere as at Feb 2020. [details]

 Taxonomic remark

 for Medocosta Štys, 1967

Misspelling in Parker (ed.), 1982 [details]

 Taxonomic remark

 for Microsporidea

This class is named Microsporea in the treatment of Parker, 1982. [details]

 Taxonomic remark

 for 

Known from larval specimens only. Previously assigned to its own class (Planctosphaeroidea) and order, currently ... [details]

 Taxonomic remark

 for Planctosphaera Spengel, 1932

Known from larval specimens only. Previously assigned to its own class (Planctosphaeroidea) and order, currently ... [details]

 Taxonomic remark

 for Planctosphaeroidea

Status uncertain; WoRMS (2017) currently assigns the sole member of this class, Planctosphaera pelagica Spengel, to ... [details]

 Taxonomic remark

 for Promicrominosporaceae

Misspelling on "Classification" section of Parker, 1982; spelled correctly in text and index. [details]

 Taxonomic remark

 for Squamata

Treated as order in Parker, 1982 and the Paleobiology DB (2022 version), however as subclass in Ruggiero et al., ... [details]