Sea pens are colonial marine cnidarians belonging of order Pennatulacea. There are some fouteen extant families within the order living in tropical and temperate environments worldwide. Sea pens are grouped with the octocorals (soft corals) along with with sea whips and sea feathers. Phylum Cnidaria, Class Anthozoa, Subclass Alcyonaria (= Octocorallia) (8-way symmetry) , Order Pennatulacea |