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| Phylum Coelenterata (Cridaria) |
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 Two layered body which is radially symmetrical |
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 Aquatic in habitat which includes both fresh water and marine |
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 The outer layer has tentacles armed with stinging cells cnidoblasts which can release venom into the victim. The inner layer encloses a body cavity called gastro vascular cavity |
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 Animals in this group exist in two types of individuals called zooids - polyps and medusae. Polyps are fixed and lead solitary or colonial life, while medusae are free swimming |
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 Alternation of generation takes place in colonial forms. Polyps and medusae alternate with each other during the life cycle |
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 Reproduction is usually asexual i.e., by budding in the polyp form and sexual in medusa form |
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 Exoskeleton made of lime is found in corals |
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| Example: Hydra, Obelia, Aurelia, Metridium |
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