World's Most Colorful and Unique Jellies. Most jellies have four part symmetry. This was taken at the jellyfish display area of the Aquarium of the Americas in New Orleans. The structure of their bodies separate Scyphozoans from "fake" jellyfish. jellyfish have no head, brain, skeleton or any organs used for respiration and excretion. his means that all body parts come from a central area. For example, the tentacles of a jellyfish usually encircle the mouth.