Family Pelagiidae Gegenbaur 1856

Diagnosis of the genus Pelagia Péron & Lesueur 1809 (redefined, after Gershwin & Collins 2002)

Pelagiidae with exumbrella covered by conspicuous cnidocyst warts; eight marginal tentacles alternating with eight marginal sense-organs located on shallow sensory pits; 16 marginal lappets; 16 unbranched, simple radial septa terminating between sense organs and tentacles, dividing the gastrovascular sinus into 8 tentacular and 8 rhopalial separate pouches that do not communicate with neighbouring pouches at the umbrella margin. Direct life cycle without polyp stage.

Type species: Pelagia noctiluca (Forskål 1775)