A revision of the genus Calcigorgia (Cnidaria, Octocorallia, Acanthogorgiidae) with the description of three new species.

Octocorals of the Acanthogorgiid genus Calcigorgia have been examined, from Japan, Sea of Okhotsk, and Bering Sea. The four known species are re-described and scanning electron microscopy (SEM) images of sclerites presented. Three other species are described and depicted, bringing the total number of Calcigorgia species to seven.

Species of Elasmogorgia and Euplexaura (Cnidaria, Octocorallia) from Japan with a discussion about the genus Filigella.

Octocorals with thread-like colony shape have been re-examined, mainly from Japanese waters. The holotypes of Elasmogorgia filiformis and Filigella boninensis and a syntype of Filigella mitsukurii have been studied. Euplexaura arbuscula is identified and Euplexaura yayoii sp.

The genus Bebryce (Cnidaria, Octocorallia, Plexauridae) at Japan, with descriptions of three new species.

Three new deep-water species of Bebryce from Japan are described and depicted using Scanning Electron Microscopy: Bebryce otsuchiensis sp. n., Bebryce rotunda sp.

Melithaeidae of Japan (Octocorallia, Alcyonacea) re-examined with descriptions of 11 new species.

Japanese melithaeid type material is re-examined and re-described. The sclerites of the different species are depicted using Scanning Electron Microscopy. All Japanese species of the family Melithaeidae treated here belong to the genus Melithaea and are endemic to Japanese waters.