_Characters._--Adult: A slightly built, long-legged rail with forehead and anterior crown light gray with darker, slate-colored feather shafts; color more olive-brown on occiput and nape; eyestripe dark slate extending to occiput; superciliary from bill to eye, and stripe below eye, white; chin and throat ashy-white; sides of head, neck and breast ashy-gray, lighter on breast and whitish on abdomen; sides of abdomen ashy-brown becoming more buffy on tibia and under tail-coverts; mantle olive-colored becoming lighter and more brownish on back, rump, and scapulars; wing-coverts similar in color but feathers with broad dark brown shaft-marks; wings brown, first primary with whitish outer web; under wing gray with some lighter streaks; tail dark brown, lighter on edges; bill horn colored, tan below; feet brown; iris vermillion. Immature: Resembles adult, but head more rufous, upper parts marked with buffy rufous; eye stripe light rufous-brown; underparts tinged with rufous. _P. c. micronesiae_ differs from _P. c. collingwoodi_ Mathews of the Philippines by having more pale gray and less olivaceous-brown on the nape and shoulder; darker on the under tail-coverts; and having a shorter culmen. _P. c. brevipes_ (Ingram) of the Volcano Islands differs from _P. c. micronesiae_ by being paler on upper parts, particularly back and wing-coverts and more washed with buff below; by having a shorter, thicker culmen; and by having a shorter tarsus. _Measurements._--Measurements are shown in table 17. TABLE 17. MEASUREMENTS OF THREE SUBSPECIES OF _Poliolimnas cinereus_