Leptomedusans

the free-swimming medusae, or jellyfish, of coelenterates of the order Leptolida. They are small or medium in size; the diameter of the bell of the large medusa Aequorea reaches 40 cm. There are usually four radial canals in the gastrovascular system. The tentacles are located along the edge of the transparent bell. The canals, tentacles, and sexual glands are sometimes brightly colored. The eggs and sperm are shed into the water, where the eggs and larvae develop. The larvae, or planulae, settle on the substrate and form a polyp colony. Leptomedusans feed on plankton.