''Epiactis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

sea anemone Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...

s in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Actiniidae. There are about nineteen recognised species and the type species is ''

Epiactis prolifera ''Epiactis prolifera'', the brooding, proliferating or small green anemone, is a species of marine invertebrate in the family Actiniidae.Fautin, D. (2010). ''Epiactis prolifera'' Verrill, 1869. Accessed through: World Register of Marine Species a ...

''.

Taxonomy

A revision in 1989 determined that the genus ''Cnidopus'' was a synonym of ''Epiactis''. At this time, two new species, ''E. lisbethae'' and ''E. fernaldi'' were described and ''E. ritteri'' was restored to the genus in which it was originally placed. Four species of ''Epiactis'' are known from the Pacific coast of North America, the external brooders ''E. prolifera'' and ''E. lisbethae'' which differ in sexuality and brooding periodicity, and the internal brooders ''E. ritteri'' and ''E. fernaldi'', which differ in their cnidocyte armoury, sexuality and

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...

Species

* '' Epiactis adeliana'' Carlgren & Stephenson, 1929 * '' Epiactis arctica'' (Verrill, 1868) * ''

Epiactis australiensis ''Epiactis'' is a genus of sea anemones in the Family (biology), family Actiniidae. There are about nineteen recognised species and the type species is ''Epiactis prolifera''. Taxonomy A revision in 1989 determined that the genus ''Cnidopus'' wa ...

'' Carlgren, 1950 * '' Epiactis brucei'' Carlgren, 1939 * '' Epiactis fecunda'' (Verrill, 1899) * '' Epiactis fernaldi'' Fautin & Chia, 1986 * '' Epiactis georgiana'' Carlgren, 1927 * '' Epiactis handi'' Larson & Daly, 2015 * '' Epiactis incerta'' Carlgren, 1921 * ''

Epiactis irregularis ''Epiactis'' is a genus of sea anemones in the family Actiniidae. There are about nineteen recognised species and the type species is ''Epiactis prolifera''. Taxonomy A revision in 1989 determined that the genus ''Cnidopus'' was a synonym of '' ...

'' Carlgren, 1951 * '' Epiactis japonica'' Verrill, 1869 * '' Epiactis lewisi'' Carlgren, 1940 * '' Epiactis lisbethae'' Fautin & Chia, 1986 * '' Epiactis marsupialis'' Carlgren, 1901 * '' Epiactis neozealandica'' Stephenson, 1918 * '' Epiactis nordmanni'' Carlgren, 1921 * ''

Epiactis novozealandica ''Epiactis'' is a genus of sea anemones in the family Actiniidae. There are about nineteen recognised species and the type species is ''Epiactis prolifera''. Taxonomy A revision in 1989 determined that the genus ''Cnidopus'' was a synonym of '' ...

'' Stephenson, 1918 * ''

'' Verrill, 1869 * ''

Epiactis ritteri ''Epiactis ritteri'', the sandy anemone or Ritter's brooding anemone, is a species of sea anemone in the family Actiniidae. It is found in the Pacific Ocean on the western coast of North America in the shallow sub-littoral zone. Description ''E ...

'' Torrey, 1902 * ''

Epiactis thompsoni ''Epiactis thompsoni'', the red-striped anemone, is a species of marine invertebrate in the family Actiniidae, found in New Zealand and South Australia. They are commonly found in the rocky intertidal zone. Description and habitat The red-stripe ...

'' (Coughtrey, 1875) * ''

Epiactis vincentina ''Epiactis'' is a genus of sea anemones in the family Actiniidae. There are about nineteen recognised species and the type species is ''Epiactis prolifera''. Taxonomy A revision in 1989 determined that the genus ''Cnidopus'' was a synonym of '' ...

'' Carlgren, 1939

Description

These sea anemones have a substantial base and a smooth column. The margin and fosse are distinct and the sphincter well developed. The

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s that surround the oral disc are short and unbranched and not narrower at the base. The longitudinal muscles of the tentacles and the radial muscles of the oral disc are usually ectodermal. The mesenteries in the gastroventicular cavity are arranged hexagonally and are greater in number at the base than at the margin. Twelve or more pairs of mesenteries are perfect and the

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sper ...

s develop on these. The retractors are often very strong and are diffuse or restricted. The

cnidocytes A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive Cell (biology), cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The pre ...

include spirocysts, basitriches and microbasic p-mastigophors. Juveniles develop in brood pouches or attached to the column.

References

{{Taxonbar, from=Q3055719 Actiniidae Cnidarian genera Taxa named by Addison Emery Verrill