Jellyfish! what funny little blobby things! Ok, so, not too technical...But here's some real stuff: Jellyfish belong to the class Scyphozoa and they are invertebrates. They live in EVERY ocean around the world and even in some freshwaters. Basically, they are made up of bell-shaped jellyish flesh substance (ectoplasm) plus some tenticles...lovely. And get this: Jelly fish LACK a brain and organs, but they do have a nervous system that allows them to respond to stimuli (light, sound, prey -yummy-, predator-eeek-) effectivley. In other words, they have no brain, but...Jellyfish have feelings too!