Several species of deep-water sea anemones belonging to three genera,
Sicyonis,
Ophiodiscus and
Tealidium, previously assigned to Actinostolidae, are recorded in North Pacific and North Atlantic and described. It is shown that these genera cannot be maintained within Actinostolidae. Family Sicyonidae was reinstated for
Sicyonis and
Ophiodiscus, while
Tealidium, together with related
Anthosactis and
Hormosoma, is transferred to a new family Anthosactinidae fam.n. Recently described
Tetracoelactis, originally assigned to Exocoelactinidae, is transferred to a new family Tetracoelactinidae fam.n., which shows some affinity with Sicyonidae. Removing
Sicyonis from Actinostol-idae in the present work resulted in the validation of this family: till now wide usage of this family name was invalid because Actinostolidae Carlgren, 1893 was a junior subjective synonym of Sicyonidae Hertwig, 1882. The following new taxa are described:
Sicyonis denisovi sp.n.,
Sicyonis kuznetsovi sp.n.,
Sicyonis titanic sp.n.,
Ophiodiscus bukini sp.n.,
Ophiodiscus moskalevi sp.n.,
Tealidium konoplinorum sp.n., Anthosactinidae fam.n., Tetracoelactinidae fam.n.