Gorgonia, a genus of corals of the Alcyonarian type, in which the colony of polypes forms a branched but flattened growth, supported by an internal axis of horn (cornein) originally derived from the bases of polypes. The genus, which includes over a score of widely distributed species, is nearly allied to the black coral (Plexaura antipathes) of the Red Sea and Indian Ocean, from the black horny axis of which ornaments are often made; and to the sea-fan (Rhipidogorgia flabellum), the much branched fan-like skeleton of which is often brought home as a curiosity from the West Indies.