Treated as plural. A suborder of jellyfishes (class Hydrozoa) having gonads on the wall of the stomach and naked sense organs; (also narcomedusae) jellyfishes of this order, narcomedusans.
Origin
Late 19th century. From scientific Latin Narcomedusae, suborder name from ancient Greek νάρκη numbness + scientific Latin Medusae, plural of Medusa, former genus name.