Cubomedusae (class Scyphozoa, subclass Scyphomedusae) An order of free medusae, whose members have a cuboid or quadrangular shape with four tentacles, or groups of tentacles, at the corners. They are inhabitants of warmer waters of the oceans, and also swarm in harbours and bays. The order includes Chironex fleckeri (sea wasp) whose stings are so virulent as to be very dangerous to humans (more so than those of the Portuguese man-of-war, Physalia physalis).

Carybdeida Alternative name for Cubomedusae.