Phylum Cnidaria

Phylum Cnidaria includes around 9,000 species of soft-bodied carnivorous aquatic animals such as jellyfish, corals, sea anemones and Portuguese man o' war. They have radial symmetry, a gastrovascular cavity for digestion, stinging cells, and range in size from pencil tips to half a football field. Their bodies are made of only a few cell layers - an outer protective layer and inner digestive layer - and they have simple nervous systems and contractile cells.