We describe a new genus and species of hydrothermal vent sea anemone from the eastern north Pacific Ocean. The combination of characters in Alvinactis reu, gen. et sp. nov. is unique among currently known genera of the actiniarian superfamily Mesomyaria;

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

Sea anemones (Cnidaria, Actiniaria) are present in all marine ecosystems, including chemosynthetic environments. The high level of endemicity of sea anemones in chemosynthetic environments and the taxonomic confusion in many of the groups to which these