Acontiaria Stephenson, 1935 (additional source)
Acontiophoridae Carlgren, 1938 (additional source)
Acontiophorum (additional source)
Acontiophorum mortenseni Carlgren, 1938 (additional source)
Acraspedanthus Carlgren, 1924 (additional source)
Acraspedanthus elongatus Carlgren, 1924 accepted as Isoparactis ferax (Stuckey, 1909) (additional source)
Acthelmis Lütken, 1875 (additional source)
Acthelmis intestinalis (Fabricius, 1780) (additional source)
Actinauge Verrill, 1883 (additional source)
Actinauge abyssorum Carlgren, 1934 (additional source)
Actinauge bocki Carlgren, 1943 (additional source)
Actinauge granulata Carlgren, 1928 (additional source)
Actinauge longicornis (Verrill, 1882) (additional source)
Actinauge richardi (Marion, 1906) (additional source)
Actinauge verrillii McMurrich, 1893 (additional source)
Actineria (additional source)
Actineria dendrophora Haddon & Shackleton, 1893 (additional source)
Actineria villosa Quoy & Gaimard in de Blainville, 1830 (additional source)
Actinernidae Stephenson, 1922 (additional source)
Actinernus Verrill, 1879 (additional source)
Actinernus antarcticus (Carlgren, 1914) (additional source)
Actinernus elongatus (Hertwig, 1882) (additional source)
Actinernus michaelsarsi Carlgren, 1918 (additional source)
Actinernus nobilis Verrill, 1879 (additional source)
Actinernus robustus (Hertwig, 1882) (additional source)
Actinia bermudensis (McMurrich, 1889) (additional source)
Actinia cari Delle Chiaje, 1822 (additional source)
Actinia equina (Linnaeus, 1758) (additional source)
Actinia grobbeni Watzl, 1922 (additional source)
Actinia infecunda McMurrich, 1893 accepted as Pseudactinia infecunda (McMurrich, 1893) (additional source)
Actinia kraemeri Pax, 1914 (additional source)
Actinia melanaster Verrill, 1901 accepted as Anemonia melanaster (Verrill, 1901) (additional source)
Actinia tenebrosa Farquhar, 1898 (additional source)
Actiniaria (additional source)
Actiniidae Rafinesque, 1815 (additional source)
Actiniogeton Carlgren, 1938 accepted as Gyractis Boveri, 1893 (additional source)
Actiniogeton ambonensis (Kwietniewski, 1898) accepted as Anthopleura ambonensis (Kwietniewski, 1898) (additional source)
Actiniogeton spenceri (Haddon & Duerden, 1896) accepted as Gyractis spenceri (Haddon & Duerden, 1896) (additional source)
Actinodendron (additional source)
Actinodendron arboreum (Quoy & Gaimard, 1833) (additional source)
Actinodendron glomeratum Haddon, 1898 (additional source)
Actinodendron hansingorum Carlgren, 1900 (additional source)
Actinodendron plumosum Haddon, 1898 (additional source)
Actinodendronidae Haddon, 1898 accepted as Actinodendridae Haddon, 1898 (additional source)
Actinodiscidae Carlgren, 1949 (original description)
Actinodiscus de Blainville, 1830 accepted as Discosoma Rüppell & Leuckart, 1828 (additional source)
Actinodiscus dawydoffi (Carlgren, 1943) accepted as Discosoma dawydoffi Carlgren, 1943 (additional source)
Actinodiscus fungiformis (Verrill, 1869) accepted as Discosoma fungiforme (Verrill, 1869) (additional source)
Actinodiscus nummiformis accepted as Discosoma nummiforme Rüppell & Leuckart, 1828 (additional source)
Actinodiscus unguja (Carlgren, 1900) accepted as Discosoma unguja Carlgren, 1900 (additional source)
Actinoporus Duchassaing, 1850 (additional source)
Actinoporus elegans Duchassaing, 1850 (additional source)
Actinoporus elongatus Carlgren, 1900 (additional source)
Actinoscyphia Stephenson, 1920 (additional source)
Actinoscyphia aurelia (Stephenson, 1918) (additional source)
Actinoscyphia plebeia (McMurrich, 1893) (additional source)
Actinoscyphia saginata (Verrill, 1882) (additional source)
Actinoscyphia verrilli (Gravier, 1918) (additional source)
Actinostephanus Kwietniewski, 1897 (additional source)
Actinostephanus haeckeli Kwietniewski, 1897 (additional source)
Actinostola Verrill, 1883 (additional source)
Actinostola callosa (Verrill, 1882) (additional source)
Actinostola carlgreni Wassilieff, 1908 (additional source)
Actinostola crassicornis (Hertwig, 1882) (additional source)
Actinostola excelsa McMurrich, 1823 accepted as Actinostola crassicornis (Hertwig, 1882) (additional source)
Actinostola georgiana Carlgren, 1927 (additional source)
Actinostola groenlandica Carlgren, 1899 (additional source)
Actinostola intermedia Carlgren, 1899 accepted as Actinostola crassicornis (Hertwig, 1882) (additional source)
Actinostola kerguelensis Carlgren, 1928 (additional source)
Actinostola spetsbergensis Carlgren, 1893 accepted as Glandulactis spetsbergensis (Carlgren, 1893) (additional source)
Actinostolidae Carlgren, 1932 (additional source)
Actinothoe Fischer, 1889 (additional source)
Actinothoe albens (Stuckey, 1909) accepted as Anthothoe albens (Stuckey, 1909) (additional source)
Actinothoe albocincta (Hutton, 1879) accepted as Anthothoe albocincta (Hutton, 1879) (additional source)
Actinothoe bradleyi (Verrill, 1869) (additional source)
Actinothoe californica Carlgren, 1940 accepted as Sagartiogeton californicus (Carlgren, 1940) (additional source)
Actinothoe carlgreni (Haddon & Duerden, 1896) (additional source)
Actinothoe georgiana (Carlgren, 1899) (additional source)
Actinothoe gracillima (McMurrich, 1887) (additional source)
Actinothoe gravieri (Pax, 1912) (additional source)
Actinothoe ignea (Fischer, 1874) (additional source)
Actinothoe kerguelensis (Pax, 1922) (additional source)
Actinothoe lobata (Carlgren, 1899) (additional source)
Actinothoe longa (Verrill, 1928) accepted as Telmatactis decora (Hemprich & Ehrenberg in Ehrenberg, 1834) (additional source)
Actinothoe milmani (Haddon & Shackleton, 1893) (additional source)
Actinothoe modesta (Verrill, 1866) (additional source)
Actinothoe neozealandica (Carlgren, 1924) accepted as Anthothoe neozelanica (Carlgren, 1924) (additional source)
Actinothoe paradoxa (McMurrich, 1893) (additional source)
Actinothoe patagonica (Carlgren, 1899) (additional source)
Actinothoe plebeia (Haddon, 1898) (additional source)
Actinothoe pugnax (Verrill, 1928) (additional source)
Actinothoe pusilla (Verrill, 1928) accepted as Epiphellia pusilla (Verrill, 1928) (additional source)
Actinothoe pustulata (McMurrich, 1887) (additional source)
Actinothoe sphyrodeta (Gosse, 1858) (additional source)
Adamsia palliata (Fabricius, 1779) accepted as Calliactis palliata (Müller, 1776) (additional source)
Adamsia sociabilis Verrill, 1882 accepted as Calliactis sociabilis (Verrill, 1882) (additional source)
Aiptasia Gosse, 1858 (additional source)
Aiptasia californica Carlgren, 1952 accepted as Exaiptasia pallida (Agassiz in Verrill, 1864) represented as Exaiptasia diaphana (Rapp, 1829) (additional source)
Aiptasia carnea Andrès, 1881 accepted as Aiptasia mutabilis (Gravenhorst, 1831) (additional source)
Aiptasia diaphana (Rapp, 1829) accepted as Exaiptasia diaphana (Rapp, 1829) (additional source)