[Cubo-/Scyphomedusae] The subphylum of Cnidaria comprising the two classes Hydrozoa (comprising the subclasses Leptolida, the hydroids, hydromedusae and related forms, and Siphonophora, the siphonophores) and Scyphozoa (comprising the Scyphomedusae, that is the large medusae such as those familiar in coastal waters, and Stauromedusae, small, stalked, mobile but sedentary forms). The Medusozoa and Anthozoa together form the Cnidaria.