_Gallinula chloropus guami_ Hartert, Vögel pal. Fauna, 15, 1921, p. 1843 (Guam); Kuroda, Avifauna Riu Kiu, 1925, p. 199 (Guam); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 43 (Guam, Tinian, Saipan); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 99 (Mariana Islands); Takatsukasa and Yamashina, Dobutsu. Zasshi, 44, 1932, p. 226 (Pagan); Hand-list Japanese Birds, rev., 1932, p. 197 (Guam, Tinian, Saipan, Pagan); Hachisuka, Birds Philippine Islands, 1, 1932, p. 241 (Guam); Peters, Checklist Birds World, 2, 1934, p. 204 (Marianne Islands); Bryan, Guam. Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Hand-list Japanese Birds, 3d ed., 1942, p. 222 (Guam, Tinian, Saipan, Pagan); Mayr, Birds Southwest Pacific, 1945, p. 288 (Marianas); Downs, Trans. Kansas Acad. Sci., 49, 1946, p. 92 (Tinian); Stott, Auk, 1947, p. 525 (Saipan); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 49 (Guam, Tinian, Saipan). _Geographic range._--Micronesia: Mariana Islands--Pagan, Saipan, Tinian, Guam. _Characters._--Adult: Head and neck sooty black; upper back dark, bluish slate-gray; lower back and wing-coverts brownish; tail blackish-brown; wings dark brown, outer edge of first primary white; breast and upper abdomen dark slate-gray, feathers on sides of breast with longitudinal white streak; under wing dark with white edges; lower abdomen grayish with white-tipped feathers; vent black; under tail-coverts white; bill and frontal shield red, tip of bill yellowish; legs and feet olive-green. Adult female: Resembles adult male but usually with smaller frontal shield. Immature: Resembles adult, but forehead mottled white and brown, with sides of head less distinctly speckled with brown; crown, neck and upper back dusky brown; back, scapulars and upper tail-coverts olivaceous-brown; chin and throat whitish; breast feathers pearly-gray tipped with white; abdomen white; sides gray, washed with buff. Older birds are darker above and more brownish-gray below; frontal shield small. _G. c. guami_ resembles _G. c. indica_, but upper wing-coverts darker and near "olivaceous black"; back, rump and scapulars darker and less olivaceous brown, although not so dark as in _G. c. orientalis_. From _G. c. lozanoi_, _G. c. guami_ differs in: slightly darker upper wing-coverts; richer olivaceous-brown on back, scapulars and rump; thinner culmen with possibly less yellow coloring on tip. _G. c. guami_ resembles _G. c. sandvicensis_ Streets of the Hawaiian Islands, but has less olive wash on the feathers and a smaller frontal shield. _Measurements._--Measurements of _Gallinula chloropus_ are presented in table 18. In general, females are smaller than males. TABLE 18. MEASUREMENTS OF _Gallinula chloropus_