? Hydronema angustum — Briggs, 1938: 10
Hydractinia angusta —Peña Cantero, 2015: 380–383, fig. 7A–H (synonymy).
Remarks. Peña Cantero (2015) carried out a re-description of this species and an eXhaustive revision of the records of Hydractinia angusta, concluding that it is not clear if all the material previously assigned to this species actually belongs to it; the only certain record corresponds to the original description by Hartlaub (1904) from the Bellingshausen Sea, in West Antarctica.
Briggs (1938) recorded the species from Commonwealth Bay, at depths between 81 and 90 m.