Ceriantharia (Cnidaria) from Australia, New Zealand and Antarctica with Descriptions of Four New Species Author Stampar, Sérgio N. Laboratório de Evolução e Diversidade Aquática-LEDA, Departamento de Ciências Biológicas, Universidade Estadual Paulista (UNESP), FCL / Assis, Av. Dom Antônio, 2100, 19806 - 900, Assis, SP, Brazil Author Mills, V. Sadie NIWA Invertebrate Collection, National Institute of Water and Atmospheric Research, 301 Evans Bay Parade Hataitai, 6021 Wellington, New Zealand Author Keable, Stephen J. Australian Museum Research Institute, Australian Museum, 1 William Street, Sydney NSW 2010, Australia text Records of the Australian Museum 2020 2020-07-29 72 3 81 100 journal article 10.3853/j.2201-4349.72.2020.1762 2201-4349 4654407 62E3C79A-499F-48DE-AFD9-111D52235D33 Genus Ceriantheopsis Carlgren, 1912 Type species . Ceriantheopsis americana (Agassiz in Verrill, 1864 ) by subsequent designation ( Carlgren, 1912 , p. 24). Diagnosis . Cerianthids with alternating sterile and fertile mesenteries. Second protomesenteries fertile, reaching aboral pole. Metamesenteries arranged in mBMb. Length of all but M-metamesenteries diminishes toward multiplication chamber. Length of M-metamesenteries of first 2–4 quartets can increase toward the multiplication chamber. M3 and further mesenteries can diminish in length towards multiplication chamber ( Carlgren, 1912 ). Distribution . Previously restricted to the Atlantic Ocean (Caribbean Sea, Gulf of Mexico, US Coast and South Africa Coast), expanded in this study to the South Pacific with the description of a new species.