Anthomedusae with only 4 fully developed marginal tentacles arising from well developed hollow tentacular bulbs; 4 simple radial canals and a circular canal; mouth with 4 simple lips; Gonads with smooth surface, interradial, with or without mesenteries, without rudimentary bulbs; margin with or without cirrus-like tentacles, exceptionally with ocelli. Differences between the diagnoses of the families Protiaridae and Pandeidae appear at first rather small, but the cnidome of the Protiaridae is very particular, containing, among others, merotrichous isorhizas (a type of cnidocyst restricted to the Leptomedusae families Eirenidae, Eucheilotidae, Lovenellidae and Tiaropsidae). Hydroids are known in Halitiara inflexa (Bouillon, 1985b), and Halitiara formosa (Brinckmann-Voss, pers. comm.), and are also very different from pandeid polyps, showing some resemblance to certain thecate Campanulinidae species.