Tube-dwelling anemones or ceriantharians look very similar to sea anemones but belong to an entirely different subclass of anthozoans. They are solitary, living buried in soft sediments. Tube anemones live inside and can withdraw into tubes, which are composed of a fibrous material made from secreted mucus and threads of nematocyst-like organelles known as ptychocysts. Within the tubes of these ceriantharians, more than one polyp is present, which is an exceptional trait because species that create tube systems usually contain only one polyp per tube. Ceriantharians were formerly classified in the taxon Ceriantipatharia along with the black corals but have since been moved to their own subclass, Ceriantharia.
Edwardsia is a genus of sea anemones, the type of the family Edwardsiidae. They have eight mesenteries and live in tubes in the sand. The name, in New Latin, commemorates the French zoologist Henri Milne-Edwards.
Amphianthus is a genus of sea anemones. It is the only genus in the monotypic family Amphianthidae.
Pseudactinia is a genus of sea anemones in the family Actiniidae.
Bunodactis is a genus of sea anemones in the family Actiniidae.
Parazoanthus is a genus of anemone-like anthozoans in the order Zoantharia.
Actinia is a genus of sea anemones in the family Actiniidae. Actinia display a rare form of heteromorphosis in which a cut inflicted on a specimen can develop into a second mouth.
Peachia is a genus of sea anemone in the family Haloclavidae. Members of this genus typically burrow into soft substrates. The only part of the animal that is normally visible is the oral disc and tentacles which lie flat on the sand in a star shape. The type species is Peachia cylindrica.
Cerianthus is a genus of tube-dwelling anemones in the family Cerianthidae. Members of the genus are found worldwide. They are predators, scavengers and omnivores.
Zoanthus is a genus of anthozoans in the family Zoanthidae. It is the type genus for its family and order.
Anemonia is a genus of sea anemones belonging to the family Actiniidae.
Palythoa is a genus of anthozoans in the order Zoantharia.
Arachnactidae is a family of tube-dwelling anemones in the order Ceriantharia. It is the only family in the monotypic order Penicillaria and comprises around 38 species. They differ from other ceriantharians in the makeup of their cnidome, the relative sizes of the oral discs and the shape and structure of the mesenteries. These tube anemones dwell in parchment-like tubes immersed in soft sediment, and have two whorls of tentacles, the outer ones being much longer than the inner ones.
Actinostolidae is a family of sea anemones in the order Actiniaria. Members of this family are deep sea species, with some occurring at hydrothermal vents.
Actinostola is a genus of sea anemones in the order Actiniaria. All members of this genus are deep-sea species, with some occurring at hydrothermal vents.
Paranthus is a genus of sea anemones in the family Actinostolidae.
Pachycerianthus is a genus of marine tube-dwelling anemones in the family Cerianthidae.
Bolocera is a genus of sea anemone in the family Actiniidae.
Halcurias is a genus of cnidarians belonging to the family Halcuriidae.
