After fertilization, the gametes of a jellyfish may be released into the water as larvae (middle right) or retained in a brood pouch. After settling, the larvae change into a sedentary polyp stage (bottom right) similar to that of a coral. More polyps (bottom left) are produced by simple budding. These polyps may divide again to form the so-called ephyra larvae (middle left). These larvae eventually grow into the free-swimming medusa more familiarly known as a jellyfish (top).