Khün, 1913
Medusae with gonads generally completely surrounding manubrium (with one exception in the South Atlantic waters: Zanclea ). Mouth simple and circular. Marginal tentacles usually hollow (except in Margelopsidae and Porpitidae, where they are solid). Cnidome of medusae characterised by presence of stenoteles. Adult or larval hydroids usually with capitate tentacles.
Suborder Moerisiida
Suborder Tubulariida
Suborder Zancleida