Having the form of rays; radiated, as an actinia.

An important member of the zoophyte family, and one often introduced into aquaria, is the actinia, or sea-anemone, sometimes called sea-rose.

Great sea slugs crawled about on the bottom with gigantic starfish, and actiniae of vivid colours spread their tentacled blossoms.

Of the lowest among these orders, the Actinoid Polyps, our Actinia or sea-anemone is a good example.

In Actinia equina the mesogloea consists of fine fibres imbedded in a homogeneous matrix, and between the fibres are minute branched or spindle-shaped cells.

The Actinia mesembryanthemum is a very long-lived creature, and certain specimens are reported to have lived over twenty years in aquaria in England.