The Alcyonaria are also known as Octocorallia, as they all show octameral symmetry and posess eight feathery tentacles that connect to eight mesenteries. They are largely colonial, with polyps connected by a system of tubes. Their fossil record is rather poor, and they are not of great palaeontological importance. Modern forms include Tubipora (organ-pipe coral), Alyconium digitatum (dead man's fingers), Gorgonia flabellum (sea fans), and Heliopora coerulea (blue coral).
A sea fan, order Gorgonacea
A sea pen, order Pennatulacea
Dead man's fingers, Alcyonium digitatum
Blue coral, Heliopora coerulea, order Helioporacea
