Radiata

Abstract

Two phyla, Cnidaria and Ctenophora, are often considered together as the radiate phyla or Radiata. This classification recognizes a closer relationship between them than with other invertebrate groups and is based on their shared radial symmetry. The term ‘Coelenterata’, commonly used as an alternative to ‘Cnidaria’, is actually synonymous with the term Radiata. Whereas Porifera are multicellular forms which function at a cellular level of organization, the radiate phyla are more advanced. These phyla function at the cell tissue level, with similar cells aggregated into definite tissues.