Hydractiniidae
Hydractinia allmanii
Hydractinia americana
Hydractinia antonii
Hydractinia areolata
Hydractinia australis
Hydractinia bella
Hydractinia borealis
Hydractinia carcinicola species complex
Hydractinia cf. altispina MPM-2009
Hydractinia cf. calderi MPM-2009
Hydractinia conchicola
Hydractinia echinata
Hydractinia epiconcha
Hydractinia fucicola
Hydractinia hayamaensis
Hydractinia hooperi species complex
Hydractinia inermis
Hydractinia laevispina
Hydractinia milleri
Hydractinia minuta
Hydractinia multigranosi
Hydractinia polyclina
Hydractinia pruvoti
Hydractinia rubricata
Hydractinia serrata
Hydractinia sodalis
Hydractinia sp. 1 MPM-2009
Hydractinia sp. 2 MPM-2009
Hydractinia sp. 3 MPM-2009
Hydractinia sp. 4 MPM-2009
Hydractinia sp. G.M.
Hydractinia sp. PC-2008
Hydractinia sp. PC-2009d
Hydractinia symbiolongicarpus
Hydractinia uchidai
Hydractinia yerii
