Aceractis Andres, 1883 (basis of record)
Aceractis draytoni M. Edw. accepted as Nemactis primula (Drayton in Dana, 1846) (basis of record)
Aceractis nexilis accepted as Stephanauge nexilis (Verrill, 1883) (basis of record)
Acerominyas Andres, 1884 (basis of record)
Acerominyas viridula (Quoy & Gaimard, 1833) accepted as Actinecta viridula (Quoy & Gaimard, 1833) (basis of record)
Acontiactis gokhaleae England, 1990 (additional source)
Acontiaria Stephenson, 1935 (basis of record)
Acontiophorum bombayense Parulekar, 1968 (basis of record)
Acontiophorum bombayensis Parulekar, 1968 accepted as Acontiophorum bombayense Parulekar, 1968 (additional source)
Acontiophorum mortenseni Carlgren, 1938 (additional source)
Acontiophorum niveum Fautin, Eppard & Mead, 1988 (additional source)
Acraspedanthus elongatus Carlgren, 1924 accepted as Isoparactis ferax (Stuckey, 1909) (basis of record)
Acraspedanthus ferax (Stuckey, 1909) accepted as Isoparactis ferax (Stuckey, 1909) (additional source)
Acremodactyla Kwietniewski, 1897 (basis of record)
Acremodactyla ambonensis Kwietniewski, 1897 accepted as Actinodendron arboreum (Quoy & Gaimard, 1833) (basis of record)
Acthelmis intestinalis (Fabricius, 1780) (additional source)
Acthelmis schaudinnii Carlgren, 1921 accepted as Haliactis arctica Carlgren, 1921 (basis of record)
Actinactis accepted as Asteractis Verrill, 1869 (basis of record)
Actinactis flosculifera accepted as Actinostella flosculifera (Le Sueur, 1817) (basis of record)
Actinauge abyssorum (Gravier, 1918) accepted as Actinauge karinae Fautin, 2016 (basis of record)
Actinauge abyssorum Carlgren, 1934 (additional source)
Actinauge bocki Carlgren, 1943 (additional source)
Actinauge borealis Verrill, 1922 accepted as Hormathia nodosa (Fabricius, 1780) (basis of record)
Actinauge chilensis Carlgren, 1959 (additional source)
Actinauge consors Verrill, 1882 accepted as Paracalliactis consors (Verrill, 1882) (basis of record)
Actinauge crassa (basis of record)
Actinauge cristata Riemann-Zürneck, 1986 (additional source)
Actinauge fastigata McMurrich, 1983 accepted as Chondrophellia coronata (Verrill, 1883) (basis of record)
Actinauge fastigiata accepted as Chondrophellia coronata (Verrill, 1883) (basis of record)
Actinauge granulata Carlgren, 1928 (additional source)
Actinauge longicornis (Verrill, 1882) (basis of record)
Actinauge longicornis var. caribaea Verrill, 1883 accepted as Actinauge longicornis (Verrill, 1882) (basis of record)
Actinauge nexilis Verrill, 1883 accepted as Stephanauge nexilis (Verrill, 1883) (basis of record)
Actinauge nodosa Fabricius, 1780 accepted as Hormathia nodosa (Fabricius, 1780) (basis of record)
Actinauge nodosa var. coronata Verrill, 1883 accepted as Chondrophellia coronata (Verrill, 1883) (basis of record)
Actinauge nodosa var. tuberculosa Verrill, 1883 accepted as Actinauge verrillii McMurrich, 1893 (basis of record)
Actinauge ricardi accepted as Actinauge richardi (Marion, 1906) (basis of record)
Actinauge richardi (Marion, 1906) (additional source)
Actinauge rugosa Verrill, 1922 accepted as Hormathia nodosa (Fabricius, 1780) (source of synonymy)
Actinauge verrilli McMurrich, 1893 accepted as Actinauge verrillii McMurrich, 1893 (basis of record)
Actinauge verrillii McMurrich, 1893 (basis of record)
Actinea accepted as Actinia Linnaeus, 1767 (basis of record)
Actinea alba accepted as Sagartia alba (Cocks in Johnston, 1847) accepted as Cylista alba (Cocks in Johnston, 1847) (basis of record)
Actinea alderi Cocks, 1851 accepted as Actinothoe alderi (Cocks, 1851) (basis of record)
Actinea anguicoma accepted as Actinothoe anguicoma (Price in Johnston, 1847) (basis of record)
Actinea balii Cocks, 1851 accepted as Anthopleura ballii (Cocks, 1851) (basis of record)
Actinea ballii accepted as Anthopleura ballii (Cocks, 1851) (basis of record)
Actinea bellii (Cocks, 1851) accepted as Actinothoe bellii (Cocks, 1851) (basis of record)
Actinea bellis (Pennant, 1777) accepted as Cereus pedunculatus (Pennant, 1777) (basis of record)
Actinea biserialis accepted as Aiptasia mutabilis (Gravenhorst, 1831) (basis of record)
Actinea chiococca accepted as Actinia equina (Linnaeus, 1758) (basis of record)
Actinea chrysanthellum accepted as Halcampa chrysanthellum (Peach in Johnston, 1847) (basis of record)
Actinea chrysosplenum accepted as Chrysoela chrysosplenium (Cocks in Johnson, 1847) (basis of record)
Actinea chrysosplinum accepted as Chrysoela chrysosplenium (Cocks in Johnson, 1847) (basis of record)
Actinea coriacea accepted as Urticina felina (Linnaeus, 1761) (basis of record)
Actinea crassicornis accepted as Hormathia digitata (O.F. Müller, 1776) (basis of record)
Actinea crassicornis accepted as Urticina felina (Linnaeus, 1761) (basis of record)
Actinea dianthus accepted as Metridium senile (Linnaeus, 1761) (basis of record)
Actinea gemmacea accepted as Aulactinia verrucosa (Pennant, 1777) accepted as Bunodactis verrucosa (Pennant, 1777) (basis of record)
Actinea johstoni accepted as Cereus pedunculatus (Pennant, 1777) (basis of record)
Actinea margaritifera accepted as Actinia equina (Linnaeus, 1758) (basis of record)
Actinea mesembryanthemum accepted as Actinia equina (Linnaeus, 1758) (basis of record)
Actinea monile accepted as Anthopleura monile (Templeton, 1836) (basis of record)
Actinea parasitica accepted as Calliactis parasitica (Couch, 1842) (basis of record)
Actinea pelucida Cocks, 1851 accepted as Actinothoe pellucida (Cocks, 1851) (basis of record)
Actinea templetonii accepted as Cereus pedunculatus (Pennant, 1777) (basis of record)
Actinea troglodytes accepted as Sagartia troglodytes (Price in Johnston, 1847) accepted as Cylista troglodytes (Price in Johnston, 1847) (basis of record)
Actinea tuberculata accepted as Urticina tuberculata (Cocks, 1851) (basis of record)
Actinea viduata accepted as Sagartiogeton viduatus (Müller, 1776) accepted as Sagartia (Cylista) viduata (Müller, 1776) (basis of record)
Actinea yarrellii (basis of record)
Actinecta de Blainville, 1830 (basis of record)
Actinecta coerulea (Lesson, 1830) (basis of record)
Actinecta cyanea (Brandt, 1835) (basis of record)
Actinecta flava (Péron & Le Sueur in Le Sueur, 1817) (basis of record)
Actinecta olivacea (Le Sueur, 1817) (basis of record)
Actinecta torpedo (Bell, 1886) (basis of record)
Actinecta tuberculosa Quoy & Gaimard, 1833 accepted as Phlyctenactis tuberculosa (Quoy & Gaimard, 1833) (basis of record)
Actinecta ultramarina (Péron & Le Sueur in Le Sueur, 1817) (basis of record)
Actinecta viridula (Quoy & Gaimard, 1833) (basis of record)
Actineria dendrophora Haddon & Shackleton, 1893 (additional source)
Actineria hemprichi Ehrenberg accepted as Megalactis hemprichii Ehrenberg, 1834 (basis of record)
Actineria villosa Quoy & Gaimard in de Blainville, 1830 (additional source)
Actinernidae Stephenson, 1922 (additional source)
Actinernus antarcticus (Carlgren, 1914) (basis of record)
Actinernus aurelia Stephenson, 1918 accepted as Actinoscyphia aurelia (Stephenson, 1918) (basis of record)
Actinernus elongatus (Hertwig, 1882) (additional source)
Actinernus michaelsarsi Carlgren, 1918 (additional source)
Actinernus nobilis Verrill, 1879 (basis of record)
Actinernus novilis accepted as Actinernus nobilis Verrill, 1879 (basis of record)
Actinernus plebeius McMurrich, 1893 accepted as Actinoscyphia plebeia (McMurrich, 1893) (basis of record)
Actinernus plebejus McMurrich, 1893 accepted as Actinoscyphia plebeia (McMurrich, 1893) (basis of record)
Actinernus robustus (Hertwig, 1882) (additional source)
Actinernus saginatus Verrill, 1882 accepted as Actinoscyphia saginata (Verrill, 1882) (basis of record)
Actinernus verrilli Gravier, 1918 accepted as Actinoscyphia verrilli (Gravier, 1918) (basis of record)
Actinia (Acthelmis) (basis of record)
Actinia (Acthelmis) intestinalis Fabricius, 1780 accepted as Acthelmis intestinalis (Fabricius, 1780) (basis of record)
Actinia (Actinoloba) dianthus Ellis, 1768 represented as Actinia dianthus Ellis, 1768 accepted as Metridium dianthus (Ellis, 1768) (basis of record)
Actinia (Chondractinia) (basis of record)
Actinia (Chondractinia) digitata Müller, 1776 accepted as Hormathia digitata (O.F. Müller, 1776) (basis of record)
Actinia (Chondractinia) nodosa Fabricii, 1780 accepted as Hormathia nodosa (Fabricius, 1780) (basis of record)

Madeira for Sagartia affinis Johnson, 1861 

 Homonymy

 for Actinia striata Quoy & Gaimard, 1833

Junior primary homonym of *Actinia striata* Risso, 1826 (type of *Paractinia*) [details]

 Homonymy

 for Actinia striata Rizzi, 1907

Junior primary homonym of *Actinia striata* Risso, 1826 (type of *Paractinia*), and of Quoy and Gaimard, 1833 [details]

 Synonymy

 for Anemonia melanaster (Verrill, 1901)

Status of the species needs investigation [details]

 Taxonomy

 for Corynactis albida Agassiz, 1859

This is not considered a valid species. The name has been applied to two species: Haloclava producta (Stimpson, ... [details]

 Validity

 for Boloceroides hermaphroditica Carlgren, 1900

Possible synonym of Bolocera mcmurrichi. [details]

 Validity

 for Edwardsioides mamillata (Bourne, 1916)

nomen dubium according to Williams, 1981 [details]

 Validity

 for Euphellia cinclidifera Pax, 1908

Also treated as a synonym of Telmatactis cricoides (Duchassaing, 1850). [details]