Immortal jellies

Jellyfish or jellies are the major non-polyp form of individuals of the phylum Cnidaria. They are typified as free-swimming marine animals consisting of a gelatinous umbrella-shaped bell and trailing tentacles. Large, often colorful, jellyfish are common in coastal zones worldwide. Fast Facts about Jellies 1. Jellyfish have roamed the seas for at least 500 million