Alcyonacea

(invertebrate zoology) The soft corals, an order of littoral anthozoans of the subclass Alcyonaria.

An order of the subclass Alcyonaria. Alcyonacea, the soft corals (see illustration), are littoral anthozoans, which form massive or dendriform colonies with yellowish, brown, or olive colors. Most attach to some solid substratum; however, some remain free in sandy or muddy places. The only skeletal structures are small, elongated, spindle-shaped or rod-like, warty sclerites which are scattered over the mesoglea. The colony is supple and leathery. The polyp body is embedded in the coenenchyme, from which retractile anthocodia protrude in Alcyonium. In Xenia and Heteroxenia, anthocodia are nonretractile. The polyp base is protected by many sclerites and is termed a calyx. See also Alcyonaria; Coelenterata.

Alcyonaceans. (a) Alcyonium palmatum (after Y. De/age). (b) Dendronephthya sp. (after H. Utinomli).