Coelenterate

Coelenterates, also known as Cnidarians (alternate phylum name) are a phylum of marine invertebrates.

They are divided into 4 major classes:

Anthozoa	Hydrozoa	Scyphozoa	Cubozoa
Coral & sea anemones	Hydroids, Portuguese Man-o-War	Jellyfishes	Box Jellyfish

Most Coelenterates obtain prey by catching small planktonic creatures with nematocysts located in their tentacles.