Coelenterata

Coelenterata was the name for an animal phylum. It is not used now. It was broken down into two separate phyla: the Cnidaria (jellyfish) and the Ctenophora (comb jellies). This change was made on the evidence of molecular evolution. This makes use of protein amino acid sequences, and whole genome DNA analysis.Arthur, Wallace 1997. The origin of animal body plans: a study in evolutionary developmental biology. Cambridge.Nielsen, Claus 2001. Animal evolution: interrelationships of the living phyla. 2nd ed, Oxford.

 Classes 
The phylum is specified into three types of classes based on their polymorphism or the structure of reproductive body i.e. Polyp & Medusa. They are:

1. Hydrozoa: Both polymorphic forms are in exist.

2. Scyphozoa: Medusa form is leading and dominant form.

3. Anthozoa: Polyp form is dominant of the organisms within the system of Coelenteratas.

Almost of them are exclusively marine.

 References 

Category:Invertebrates