These animals have an eight-fold symmetry. Most are colonial sessile polyps. Octocorallia look like the stony corals. Stony corals have a six-fold symmetry, and are classified in the group Hexacorallia. Unlike the stony corals, most Octocoralllia lack a lasting skeleton. For this reason, they do not build coral reefs. An older name for this group is Alcyonaria. 