:  The Jellyfish
Scyphozoa: Jellyfish
Body Form: The jellyfish body is a 'medusa' - a short wide body with tentacles attached around an opening that serves as the mouth. The body wall is thick and has a significant mesoglea layer between. Stinging cells called nematocysts are used to paralyze and catch prey.
Natural History: The scyphozoans include the jellyfishes of the ocean. Jellyfishes 'swim' through the water by contractions of the bell. While adult jellyfish are mobile, larval jellyfish produced by sexual reproduction are polyps that attach to the sea floor. Many jellyfish can deliver potent stings - the most venomous animal in the world is a box jellyfish - Chironomas. Prey that is stung becomes paralyzed and is drawn into the gut to be digested.