Characteristics:
Unlike other cnidarians, the sea anemones and corals do not have a medusa stage in their life cycle. Their eggs form larvae which attach to some surface and start developing a new animal or colony. Each animal or polyp have a cylindrical body and one or more rings of tentacles around the mouth. Some anthozoans have the ability of both sexual and asexual reproduction.
Taxonomy:
The anthozoans are divided into two subclasses. The members of Hexacorallia, like sea anemones, tube anemones and stony corals, have a sixfold radial symmetry. The number of tentacles, for instance, often come in a plural of six. The other subclass, Octocorallia, include species like soft corals and sea pens, with an eightfold symmetry.