One of the orders of Anthozoa. It includes the Alcyonacea, Pennatulacea, and Gorgonacea.

corals and sea anemones having eight branches

Alcyonaria (also known as Octocorallia, as they have 8-fold symmetry) is a subclass of the class Anthozoa within the phylum Cnidaria. It includes the sea fans and sea pens, and the soft corals of the order Alcyonacea.