Hydrozoa Owen, 1843
Armorhydridae Swedmark & Teissier, 1958
Hydrolariidae
Jindexiangus Xu & Huang, 2006
Microhydridae
Microhydrulidae Bouillon & Deroux, 1967
Monobrachiidae Mereschkowsky, 1877
Olindiadidae
Olindiasidae
Olindiidae Haeckel, 1879
