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
Lion's mane jellyfish shore. Like other jellyfish, lion's manes are capable of both sexual reproduction in the medusa stage and asexual reproduction in the polyp stage. Lion's mane jellyfish have four different stages in their year-long lifespan: a larval stage, a polyp stage, an ephyrae stage, and the medusa stage. The female jellyfish carries its fertilized eggs in its tentacle, where the eggs grow into larva. When the larva are old enough, the female deposits them on a hard surface, where the larva soon grow into polyps. The polyps begin to reproduce asexually, creating stacks of small creatures called ephyrae. The individual ephyrae