Jellyfish Jellyfish Jellyfish or sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are not mobile, being anchored to the seabed by stalks. The bell can pulsate to provide propulsion and highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle; the medusa is normally the sexual phase, the planula larva can
Cyanea (jellyfish) Cyanea (jellyfish) Cyanea is a cosmopolitan genus of stinging jellyfish, primarily found in northern waters of the Atlantic and Pacific Oceans. The same genus name has been given to a genus of plants of the Hawaiian lobelioids, an example of a "parahomonym" (same name, different kingdom). The taxonomy of "Cyanea" species is not fully agreed upon. Some zoologists have suggested that all species within the genus should be treated as one. However, in the North Sea at least, the lion's mane jellyfish and the blue jellyfish appear as distinct species. "Cyanea" may be a species complex of recently diverged species.