Anthozoa [ 4 ] Anthozoa is subdivided into two subclasses Octocorallia and Hexacorallia which form monophyletic groups and generally show 8-way and 6-way symmetry in polyp structure respectively. [ 5 ] Historically Ceriantipatharia was thought to be a separate subclass but the two orders it comprised, Ceriantharia and Antipatharia , are