_Porphyrio melanotus_ Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 8, 117, 118 (Pelew); Gray, Hand-list Birds, 3, 1871, p. 64 (Pelew). _Porphyrio melanotus pelewensis_ Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 61 (Pelew); Bolau, Mitteil. Naturhist. Mus. Hamburg, 1898, p. 70 (Palau); Dubois, Syn. Avium, 2, 1904, p. 976 (Pelew); Mathews, Birds Australia, 1, 1911, p. 241 (Pelew); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 43 (Pelew); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 100 (Pelew); Hand-list Japanese Birds, rev., 1932, p. 197 (Palau); Hachisuka, Birds Philippines, 1, 1932, p. 245 (Pelew). _Porphyrio pelewensis_ Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5, 39 (Palau); Salvadori, Atti Accad. Sci. Torino, 14, 1879, p. 1169 (Pelew); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 407 (Palau); Finsch, Deut. Ver. zum Schutze der Vogelwelt, 18, 1893, p. 459 (Palau); Sharpe, Cat. Birds British Mus., 23, 1894, p. 206 (Pelew); Nehrkorn, Nat. Eiers., 1899, p. 205 (Palau-Inseln); Matschie, Journ. f. Ornith., 1901, p. 113 (Palau); Reichenow, Die Vögel, 1, 1913, p. 216 (Palauinseln); Takatsukasa and Kuroda, Tori, 1, 1915, p. 51 (Pelew). _Porphyrio cyanocephalus_ Elliot, Stray Feathers, 7, 1878, pp. 10, 13 (Palau). _Porphyrio poliocephalus pelewensis_ Peters, Check-list Birds World, 2, 1934, p. 208 (Pelew); Hand-list Japanese Birds, 3d ed., 1942, p. 222 (Koror). _Porphyrio porphyrio pelewensis_ Mayr, Birds Southwest Pacific, 1945, p. 288 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 49 (Angaur). _Geographic range._--Micronesia: Palau Islands--Koror, Angaur. _Characters._--Adult: A large, purplish-blue, marsh bird with crown and sides of head dusky-black; wing-coverts purplish-blue; rest of upper parts dark, washed with olivaceous-brown; outer webs of primaries and secondaries tinged with purplish-blue; chin, axillaries and under wing-coverts dusky; under tail-coverts whitish; rest of underparts purplish-blue, blacker on abdomen. _Porphyrio p. pelewensis_ resembles _P. p. palliatus_ Bruggemann of Celebes and _P. p. melanopterus_ Bonaparte of the Moluccas and New Guinea but upper parts paler and slightly less glossy; lesser and primary wing-coverts more purplish-blue and less greenish-blue; outer webs of primaries and secondaries lighter purplish-blue; underparts less blue with patch on throat and breast paler blue with less green (patch present on only one specimen from the Palaus). _Measurements._--Measurements of one male: wing, 227; tail, 81; culmen and shield, 62.5; tarsus, 77; of three females: wing, 212, 218, 227; tail, 77, 81, 86; culmen and shield, 57, 61, 64; tarsus, 75, 75, 77.