In the present paper, two new species, Acanthaxius kashimaensis sp. nov. and A. pseudopolyacanthus sp. nov., are described and a revised key to the species of the genus Acanthaxius Sakai & De Saint Laurent, 1989 is presented. In addition, Balssaxius habereri (Balss, 1913) and Boasaxius princeps (Boas, 1880) of the family Axiidae Huxley, 1879, Neaxius glyptocercus (Von Martens, 1869) of the family Strahlaxiidae Poore, 1994, together with Trypaea truncata (Giard & Bonnier, 1890) of the family Callianassidae Dana, 1852, and two species, Calliax lobata (De Gaillande & Lagardère, 1966) and Calliaxina punica (De Saint Laurent & Manning, 1982), of the family Eucalliacidae Manning & Felder, 1991 [sensu Sakai, 2011], are commented upon. The descriptions given herein result from the examination of specimens collected from Ise-Shima, Mie Prefecture and Ôfunato-City, Iwate Prefecture, as well as from Iriomote Island, Ryukyu Islands, Japan, and from material collected from Salamis, Saronikos Gulf, Greece, and the Palinuro Seamount, southern Tyrrhenian Sea, Italy.