Anthozoa (sea-anemones, corals, sea pens; phylum Cnidaria) A class of exclusively polyploid, marine cnidarians. They probably first appeared in the Ordovician although there are possible records for some groups in the Cambrian. They are solitary or colonial and usually sedentary. The oral end is expanded as an oral disc with a central mouth that has one or more rings of hollow tentacles. Anthozoans have a well-developed stomodeum (gullet) leading from the mouth to the enteron (gastrovascular cavity). The interior of the enteron is divided by mesenteries (infoldings of the gut wall). Those members of the class that secrete hard, calcareous skeletons are important in the geologic record from the Palaeozoic onwards, and at some levels form true coral reefs. In the Palaeozoic they are often associated with other organisms, e.g. stromatoporoids (Stromatoporoidea), to produce organic build-ups or reef mounds. See HETEROCORALLIA; OCTOCORALLIA; RUGOSA; SCLERACTINIA; TABULATA; and ZOANTHARIA.
Anthozoa (Actinozoa; sea anemones, corals, sea pens; phylum Cnidaria) A class of exclusively polypoid, marine cnidarians that are solitary or colonial, and usually sedentary. The oral end is expanded as an oral disc with a central mouth, with one or more rings of hollow tentacles. A well-developed stomodaeum leads from the mouth to a gastrovascular cavity, generally with one or two vertical grooves. The gastrovascular cavity is partitioned into compartments by complete or incomplete mesenteries, some bearing endodermal gonads. Anthozoans first appeared in the Ordovician.
More From encyclopedia.com
Sea Urchin , sea ur·chin • n. a marine echinoderm that has a spherical or flattened shell covered in mobile spines, with a mouth on the underside and calcareous j… sea pen , sea pen See ANTHOZOA; and PENNATULACEA. Opisthobranchs , Opisthobranchia (phylum Mollusca, class Gastropoda) A subclass of marine organisms, which are often ‘naked’, including the sea slugs and pteropods, r… Sea breeze , sea breeze See LAND AND SEA BREEZES. sea breeze See land and sea breezes. Sea Slug , sea slug (nudibranch) Any of numerous species of marine gastropod molluscs, related to snails and found worldwide. They have no shells, quills or man… Pennatulacea , Pennatulacea (sea pens; class Anthozoa, subclass Octocorallia) An order of colonial octocorals that have an elongate primary polyp embedded in mud on…
About this article
All Sources -
Updated Aug 08 2016 About encyclopedia.com content Print Topic
You Might Also Like