Characteristics of the Order (from Kramp 1961)

Scyphomedusae with umbrella margin not cleft into lappets; with four interradial tentacles or groups of tentacles situated on gelatinous, wing-shaped or spatula-shaped structures (pedalia); with four perradial sense organs situated within niches on the sides of the bell; with four wide perradial sacs extending outwards from the central stomach into the subumbrellar cavity, incompletely separated by interradial septa; with four pairs of leaf-shaped gonads attached along the interradial septa and extending into the gastrovascular space; the opening of the bell cavity partly closed by an annular diaphragm (velarium).