For 10 points, name this radially-symmetric invertebrate phylum that includes corals and jellyfish.
This phylum's class Anthozoa is mostly sessile. Its class Cubozoa includes the deadly sea wasp. Members of this phylum have a jelly-like layer called the mesoglea. This phylum's polyp body plan is exhibited by (*) hydras. This phylum's name is derived from the name of its harpoon-like stinging cells. For 10 points, name this radially-symmetric invertebrate phylum that includes corals and jellyfish.
This phylum's class Anthozoa is mostly sessile. Its class Cubozoa includes the deadly sea wasp.
Cnidaria (accept Cnidarians; prompt on Coelenterata)