Click the links to browse through the WoRMS marine species taxonomy.
Animalia
  Mollusca
  Porifera
  Platyhelminthes
  Nematoda
  Annelida
  Nemertina
  Arthropoda
  Ctenophora
  Cnidaria
    Anthozoa
    Hydrozoa
      Hydroidolina
        Siphonophorae
        Anthoathecata
          Capitata
          Filifera
            Bougainvilliidae
            Clavidae
            Eudendriidae
            Hydractiniidae
              Clava
              Hydractinia
                  Hydractinia aculeata
                  Hydractinia allmani
                  Hydractinia arctica
                  Hydractinia calderi
                  Hydractinia carica
                  Hydractinia echinata
                  Hydractinia fucicola
                  Hydractinia fuciola
                  Hydractinia humilis
                  Hydractinia ingolfi
                  Hydractinia monocarpa
                  Hydractinia ornata
                  Hydractinia serrata
                  Hydractinia pruvoti
                  Hydractinia tenuissima
                  Hydractinia carnea
                  Hydractinia lactea
                  Hydractinia areolata
                  Hydractinia incerta
                  Hydractinia borealis
                  Hydractinia solitaria
                  Hydractinia inermis
                  Hydractinia claviformis
                  Hydractinia americana
                  Hydractinia polyclina
                  Hydractinia valens
                  Hydractinia angusta
                  Hydractinia clavata
                  Hydractinia kaffraria
                  Hydractinia vallini
                  Hydractinia parvispina
                  Hydractinia hooperi
                  Hydractinia aggregata
                  Hydractinia altispina
                  Hydractinia apicata
                  Hydractinia arge
                  Hydractinia armata
                  Hydractinia australis
                  Hydractinia bayeri
                  Hydractinia bella
                  Hydractinia betkensis
                  Hydractinia brachyurae
                  Hydractinia californica
                  Hydractinia canalifera
                  Hydractinia carcinicola
                  Hydractinia carolinae
                  Hydractinia conchicola
                  Hydractinia cryptoconcha
                  Hydractinia cryptogonia
                  Hydractinia cytaciformis
                  Hydractinia dendritica
                  Hydractinia diogenes
                  Hydractinia disjuncta
                  Hydractinia dubia
                  Hydractinia epiconcha
                  Hydractinia epispongia
                  Hydractinia exigua
                  Hydractinia fallax
                  Hydractinia granulata
                  Hydractinia hancocki
                  Hydractinia hayamaensis
                  Hydractinia inabai
                  Hydractinia laevispina
                  Hydractinia longispina
                  Hydractinia mar
                  Hydractinia marsupialia
                  Hydractinia meteoris
                  Hydractinia milleri
                  Hydractinia minoi
                  Hydractinia misakiensis
                  Hydractinia monoon
                  Hydractinia multigranosi
                  Hydractinia multispina
                  Hydractinia multitentaculata
                  Hydractinia nassa
                  Hydractinia novaezelandiae
                  Hydractinia ocellata
                  Hydractinia otagoensis
                  Hydractinia pacifica
                  Hydractinia paucispinata
                  Hydractinia piscicola
                  Hydractinia polycarpa
                  Hydractinia proboscidea
                  Hydractinia prolifica
                  Hydractinia quadrigemina
                  Hydractinia rubricata
                  Hydractinia rugosa
                  Hydractinia sarsii
                  Hydractinia selena
                  Hydractinia siphonis
                  Hydractinia sodalis
                  Hydractinia spinipapillaris
                  Hydractinia spiralis
                  Hydractinia symbiolongicarpus
                  Hydractinia symbiopollicaris
                  Hydractinia tenuis
                  Hydractinia thatcheri
                  Hydractinia uchidai
                  Hydractinia yerii
                  Hydractinia tournieri
                  Hydractinia nagaoensis
                  Hydractinia sandrae
                  Hydractinia cytaeiformis
                  Hydractinia vacuolata
                  Hydractinia polytentaculata
                  Hydractinia dongshanensis
                  Hydractinia uniformis
                  Hydractinia antonii
                  Hydractinia reticulata
                  Hydractinia minima
                  Hydractinia gorgonoides
                  Hydractinia anechinata
                  Hydractinia minuta
                  Hydractinia denhami
                  Hydractinia reticulata
                  Hydractinia reticulata
                  Hydractinia rosea
                  Hydractinia grisea
                  Hydractinia michaelseni
                  Hydractinia verdi
                  Hydractinia uchidai
                  Hydractinia spiralis
                  Hydractinia recurvatus
                  Hydractinia phialiformis
                  Hydractinia munita
                  Hydractinia epidocleensis
                  Hydractinia alderi
                  Hydractinia guangxiensis
                  Hydractinia moniliformis
              Hydractomma
              Podocoryna
              Stylactaria
              Stylactis
              Clavactinia
              Cnidostoma
              Hydrocorella
              Janaria
              Fiordlandia
              Parahydractinia
              Hydroconophora
              Echinochorium
              Rhizocline
              Cytaeandra
              Hydrodendrium
              Nuttingia
              Euhydractinia
              Hydronema
              Hydrissa
              Podocorella
              Halorhiza
              Calycidion
            Pandeiidae
            Proboscidactylidae
            Pandeidae
            Rathkeidae
            Trichydridae
            Margelina
            Filifera incertae sedis
            Pandeida
            Calycopsidae
            Cytaeididae
            Niobiidae
            Ptilocodiidae
            Stylasteridae
            Laingiidae
            Protiaridae
            Russelliidae
            Bythotiaridae
            Oceaniidae
            Eucodoniidae
            Australomedusidae
            Balellidae
            Jeanbouilloniidae
            Platystomidae
            Tubiclavoididae
            Cordylophoridae
            Magapiidae
            Axoporidae
            Heterotentaculidae
          Anthoathecata incertae sedis
        Leptothecata
        Laingiomedusae
        Anthomedusae
        Leptomedusae
        Gymnoblastea
        Athecata
        Thecata
        Siphonophora
      Trachylinae
      Hydroida
      Leptolinae
    Cnidaria incertae sedis
    Cubozoa
    Scyphozoa
    Staurozoa
  Sipuncula
  Echiura
  Pogonophora
  Entoprocta
  Tardigrada
  Phoronida
  Brachiopoda
  Echinodermata
  Hemichordata
  Chordata
  Gastrotricha
  Chaetognatha
  Ectoprocta
  Mesozoa
  Rotifera
  Gnathostomulida
  Acanthocephala
  Cycliophora
  Cephalorhyncha
  Placozoa
  Bryozoa
  Myxozoa
  Sipunculida
  Pentastomida
  Nemertini
Plantae
Fungi
Protozoa
Bacteria
Chromista
Archaea
Viruses
Monera