Class: Hydrozoa Owen, 1843

Subclass Hydroidolina Collins & Marques, 2004

   Order: Thecata (Leptomedusae) Fleming, 1828
   Order: Athecata (Anthomedusae) Hincks, 1686
       Suborder: Capitata Kuhn, 1913
       Suborder: Filifera Kuhn, 1913