Family Pelagiidae Gegenbaur, 1856

Scyphomedusae with eight or 16 marginal sense organs (rhopalia); adults with tentacles on umbrella margin located in clefts between the marginal lappets; with gastrovascular space divided by radial septa into separate unbranched stomach pouches; without ring canal; having oral arms elongate and folded (Mayer, 1910; Kramp, 1961; Russell, 1970; Mianzan and Cornelius, 1999).