Mushroom corals (Scleractinia: Fungiidae) of Madang Lagoon, northern Papua New Guinea: an annotated check-list with the description of Cantharellus jebbi spec, nov.* B.W. Hoeksema Hoeksema, B.W. Mushroom corals (Scleractinia: Fungiidae) of Madang Lagoon, northern Papua New Guinea: an annotated check-list with the description of Cantharellus jebbi spec. nov. Zool. Med. Leiden 67 (1), 30.vii.1993:1-19, figs. 1-18, tab. 1.— ISSN 0024-0672. Key words: Scleractinia; Fungiidae; mushroom corals; Madang; Papua New Guinea; Bismarck Sea; distribution; new species. A check-list of mushroom corals (Fungiidae) is given with annotations on their distribution in Madang Lagoon, northern Papua New Guinea, Bismarck Sea. A total of 36 fungiid species is recorded from this locality, which is more than from any other studied so far. One species, Cantharellus jebbi spec, nov., is new to science. It is the only monostomatous mushroom coral species known that is entirely encrusting. It also represents the first record of a recent Cantharellus species in the Indo- Malayan region. Bert W. Hoeksema, National Museum of Natural History, P.O. Box 9517, 2300 RA Leiden, The Netherlands. Introduction In connection to the 7th International Coral Reef Symposium at Guam (22-26 June 1992), during which special attention was given to the theme "Biodiversity and biogeography of marine invertebrates of the north coast of New Guinea", field work was performed in the vicinity of the Christensen Research Institute (CRI) at Madang, northern Papua New Guinea. This field work offered the opportunity to compare the scleractinian reef coral fauna of northern New Guinea with that of other areas in the Indo-Malayan region (Hoeksema, in press). In this comparison, emphasis was put on mushroom corals (Scleractinia: Fungii- dae), since extensive distribution data of these species were already available from neighbouring areas (Hoeksema, 1989). North Papua New Guinea records were also obtained from corals recently collected at Laing Island, Hansa Bay (Claereboudt & Hoeksema, 1987; Claereboudt, 1988, 1989; Hoeksema, 1989), which were studied in the Royal Belgian Institute of Natural Sciences (IRSNB/KBIN) at Brussels. In addition small collections of corals from Madang Lagoon were studied in the California Academy of Sciences (CAS) at San Francisco, and in the Zoological Museum at Berlin (ZMB). The collection at the CAS is recent, while the one at the ZMB was collected under German colonial rule, when northern Papua New Guinea was known as Kaiser Wilhelmsland and Madang was called Friedrich Wilhelmshafen. Altogether, the field work and the museum study resulted in a total of 39 species known from northern New Guinea, which is more than from any other area (Hoeksema, in press). * Contribution No. 94 from the Christensen Research Institute, Madang.