Narcomedusae hydrozoan. Narcomedusae often have either no, or a very reduced, polyp stage. When mature, medusae release gametes (sex cells) freely into the ocean. Gametes of opposite sexes combine to form free-swimming larval zygotes. These either settle on a suitable substrate, or swim and develop into another medusae or polyp directly. Photographed in the Laccadive Sea, Maldives.