How many species of jellyfish are there? Jellyfish are sometimes called sea jellies. They belong to a group called Medusozoa which is divided into four classes: Hydrozoa, Scyphozoa, Cubozoa and ...

Some species never grow up; they remain branching colonies of polyps. And one hydrozoan, the immortal jellyfish (Turritopsis dohrnii), seen here in a water drop, has a life cycle that skips death ...

An adult jellyfish is known as a medusa. Jellyfish belong to a group called Cnidaria, which also includes sea anemones and corals. As animals, they are subject to the cycle of life and death - though ...

"Based on their findings, the jellyfish belong to the Physalia physalis ... "This species, classified as a marine hydrozoan, is easily recognised by its translucent bluish appearance.

The species superficially resembles a jellyfish, but is actually a siphonophore ... classified under the marine hydrozoan group, is easily identified by its translucent bluish-purple or pink ...