Hexacorallia - Sea anemones and stony corals

Five orders of Hexacorallia are represented in Britain. Pictures and examples of some of these follow:

Sea anemones consist of solitary polyps. The base of the column is a flattened adherent disc in rock dwellers. Burrowing forms have a rounded base. There are 44 species in British waters. Identification may be difficult. Colour is not usually a good guide. Anemones are identified by the number and shape of the tentacles, and the structure of the column. The size of the anemone and its habitat are also good guides to identification.

BEADLET ANEMONE Actinia equina. 5cm diameter.
Common on all coasts of Britain. When exposed to air at low tide this anemone retracts its tentacles and resembles a blob of jelly, which is firmly attached to the rocks. It covers itself with mucus to withstand desiccation. They can be red, brown or orange.

When covered with water and seeking food the tentacles are expanded. They are of moderate length and never banded. Beadlet anemones reproduce by viviparity, producing fully formed young anemones.

The rim of the disc has a groove in which are spots, usually blue. The only other species with these spots are the green beadlet and the strawberry anemone. Very common on all coasts of Britain, Western Europe and probably West Africa. From high on shore to 20m.

STRAWBERRY ANEMONE Actinia fragacea. 10cm diameter.
Resembles a large beadlet anemone. Red with yellowish, greenish or bluish spots. Green specimens with spots are beadlets. Local in the English Channel and S.W.England. In some books it is regarded as a variety of beadlet but its reproduction differs. It is not viviparous like beadlet anemones but their eggs are shed into the sea.

GEM ANEMONE Bunodactis verrucosa 2.5cm diameter.
Pink and grey anemone. Column with vertical rows of warts, 6 rows white, up to 42 dark. On shore in rock pools, especially those with coral weed. The warts resemble the fruiting bodies of the coral weed making this small anemone difficult to detect. Also found on sublittoral rocks to 20m, Viviparous. South and west Britain, south to Mediterranean.

SNAKELOCKS ANEMONE Anemonia viridis (sulcata).
20cm tentacle span.
Brownish or greyish anemone with long sinuous tentacles that are rarely retracted. Tentacles are greyish or bright green usually with purple tips. The green colour comes from symbiotic algae that live in the cells. To allow photosynthesis Anemonia lives in open situations exposed to light. In rock pools, in eel grass or kelp down to 20m.