Despite bodies that are 97 percent water, a very limited nervous system, and the lack of eyes, ears, or a brain, these phantoms of the deep travel widely, populating the world's oceans. Although many people fear jellies for their sometimes dangerous stinging abilities, when they discover the secret life of these ocean-going phantoms, their fear fades as their curiosity and sense of wonder grow.
Jellies are invertebrates with bodies that consist of a jelly-like substance called mesoglea.
Many people are familiar with jellyfish, but the lesser known jellies include organisms called comb jellies. The Cnidarians include other well-known animals such as the corals, sea anemones, and hydras. The majority of Ctenophores cannot sting and use cilia to swim. The origin of the word Cnidaria comes from the Greek word 'cnide' meaning nettle. The Cnidarians have a flower-like appearance, for example a hydra or sea anemone.