Phylum Cnidaria includes animals that show radial or biradial symmetry and are diploblastic, that is, they develop from two embryonic layers. Nearly all (about 99 percent) cnidarians are marine species. read more
One of the most important distinguishing characteristics of the phylum are the Nematocysts. Nematocysts, and their enclosing Cnidocysts come in about 24 different forms, the differences play a functional role in the classification of the phylum. A Cnidocyst is a cell that secretes a nematocyst within it. read more
Characteristics of Cnidarians All cnidarians are characterized by radially symmetric body plans, rather than the bilaterally symmetric body plans that are found in most other animal phyla. Although cnidarians are more advanced than sponges (phylum Porifera) in that they possess distinct tissue layers, they lack many of the features of more advanced animal phyla, such as internal organs and central nervous systems. read more
PHYLUM CNIDARIA-COELENTERATES CHARACTERS AND CLASSIFICATION!n 1887 Leuckart coined the name Coelenterata. His Coelenterata included sponges and Ctenophores. In 1888 Coelenterata is divided into 3 phyla. 1) Spongiaria 2) Cnidaria and 3)Ctenophora. Therefore, Cnidaria is the most suitable name for his phylum. read more