Children (134 direct children, 134 direct and indirect children):
Hydractinia angusta
Hydractinia bella
Hydractinia exigua
Hydractinia epispongia
Hydractinia multigranosi
Hydractinia ocellata
Hydractinia minoi
Hydractinia rugosa
Hydractinia meteoris
Hydractinia quadrigemina
Hydractinia arge
Hydractinia carcinicola
Hydractinia uchidai
Hydractinia conchicola
Hydractinia milleri
Hydractinia cytaeiformis
Hydractinia polyclina
Hydractinia laevispina
Hydractinia hayamaensis
Hydractinia areolata
Hydractinia piscicola
Hydractinia nagaoensis
Hydractinia carolinae
Hydractinia yerii
Hydractinia tenuis
Hydractinia symbiolongicarpus
Hydractinia hancocki
Hydractinia carica
Hydractinia cryptogonia
Hydractinia bayeri
Hydractinia parvispina
Hydractinia vacuolata
Hydractinia otagoensis
Hydractinia monocarpa
Hydractinia pacifica
Hydractinia dendritica
Hydractinia americana
Hydractinia echinata
Hydractinia fucicola
Hydractinia armata
Hydractinia sodalis
Hydractinia californica
Hydractinia epiconcha
Hydractinia arctica
Hydractinia antonii
Hydractinia anechinata
Hydractinia longispina
Hydractinia inermis
Hydractinia aggregata
Hydractinia canalifera
Hydractinia altispina
High-spined commensal hydroid
Hydractinia paucispinata
Hydractinia verdi
Hydractinia polycarpa
Hydractinia disjuncta
Hydractinia allmani
Hydractinia mar
Hydractinia inabai
Hydractinia australis
Hydractinia borealis
Hydractinia recurvatus
Hydractinia rubricata
Hydractinia spinipapillaris
Hydractinia aculeata
Hydractinia humilis
Hydractinia michaelseni
Hydractinia munita
Hydractinia vallini
Hydractinia dongshanensis
Hydractinia misakiensis
Hydractinia multispina
Hydractinia granulata
Hydractinia pruvoti
Hydractinia kaffraria
Hydractinia polytentaculata
Hydractinia prolifica
Hydractinia carnea
Hydractinia novaezelandiae
Hydractinia uniformis
Hydractinia diogenes
Hydractinia betkensis
Hydractinia phialiformis
Hydractinia multitentaculata
Hydractinia marsupialia
Hydractinia apicata
Hydractinia proboscidea
Hydractinia valens
Hydractinia spiralis
Hydractinia hooperi
Hydractinia serrata
Hydractinia brachyurae
Hydractinia monoon
Hydractinia ingolfi
Hydractinia gorgonoides
Hydractinia thatcheri
Hydractinia claviformis
Hydractinia dubia
Hydractinia cryptoconcha
Hydractinia minuta
Hydractinia cytaciformis
Hydractinia sagamiensis
Hydractinia misakinensis
Hydractinia siphonis
Hydractinia kaffaria
Hydractinia vermicola
Hydractinia symbiopollocaris
Hydractinia minima
Hydractinia polystyla
Hydractinia sarsi
Hydractinia nassa
Hydractinia fallax
Hydractinia selena
Hydractinia reticulata
Hydractinia calderi
Hydractinia symbiopollicaris
Hydractinia sarsii
Hydractinia denhami
Hydractinia epidocleensis
Hydractinia guangxiensis
Hydractinia moniliformis
Hydractinia simplex
Hydractinia sandrae
Hydractinia promiscua
Hydractinia taiwanensis
Hydractinia constrictura
Hydractinia phyllosoma
Hydractinia grisea
Hydractinia incerta
Hydractinia lactea
Hydractinia leizhouensis
Hydractinia ocalana
Hydractinia rosea
Hydractinia solitaria
Hydractinia tenuissima