206 A MANUAL OF THE BIRDS OF AUSTRALIA. 
The bill is short, and very deep, at base of culmen the depth is more than half 
the length; the bill is laterally compressed but the culmen ridge widens out at 
base into an indistinct frontal plate, not covering the fore-head ; the nostrils are 
as in the preceding, linear pervious apertures placed at the anterior portion of the 
nasal groove and lying along the edge of the mandible; the tip is not decurved while 
the lower mandible is very strong and deep, the gonys ill defined and not at all 
angular, the interramal space being shallow and almost completely feathered. The 
wings are long, the first primary long, almost equal to the fourth, longer than the 
fifth, the second and third subequal and longest ; inner secondaries short. The tail 
is square and less than half the length of the wing, composed of sixteen broad strong 
feathers, the outer two on each side a little shorter than the others. The legs are 
long, the tibia exposed for nearly half the length of the tarsus, reticulate in front, 
scutellate behind ; large plates horizontally placed cover the front of the tarsus, 
the back having similar smaller plates, the sides with a narrow row of scutes between. 
The toes are shorter than the tarsus, the middle toe longest, the outer longer than 
the inner, the hind-toe long, but comparatively short. 
Coloration olive-green above, leaden-grey below ; tail black. 
142. Microtribonyx ventralis.—BLACK-TAILED WATER HEN. 
Gould, Vol. VI., pl. 72 (pt. xx.), Sept. Ist, 1845. Mathews, Vol. I., pt. 4, pl. 56, Aug. 9th, 
1911. 
Gallinula ventralis Gould, Proc. Zool. Soc. (Lond.), 1836, p. 85, Jan. 16th, 1837: Swan River, 
West Australia. 
Tribonyx ventralis whitei Mathews, Noy. Zool., Vol. XVIII., p. 194, Jan. 31st, 1912: Never- 
tire, New South Wales. 
Tribonyx ventralis territorii Mathews 7b., p. 195: Alexandra, Northern Territory. 
DistrIBUTION.—Australia generally. Not Tasmania. 
Adult male.—Olive-grey above, including the head, hind-neck, sides of neck, 
back and upper tail-coverts ; wing-coverts olive-brown ; bastard-wing, primary- 
coverts and quills blackish, olive-brown on the outer webs ; outer web of first primary 
edged with white ; tail-feathers black, fringed with olive-brown on the outer webs ; 
chin, lores and cheeks black ; lower throat, fore-neck and breast dark slate-grey, 
which extends on to the sides of the body; middle of abdomen and under tail- 
coverts black, axillaries and lower flanks brown; long flank plumes black with 
white pear-shaped spots at the tips; under wing-coverts dusky with subterminal 
black bars and white tips; bill apple-green, base of lower mandible orange ; iris 
deep yellow; tarsi and feet coral pink. Total length 340; culmen, including 
frontal shield, 32, wing 221, tail 85, tarsus 56. 
Adult female.—Very similar to the adult male but smaller, and differs in having 
the flank plumes grey instead of black, and the wing-coverts paler. Total length 
309 mm.; culmen, including frontal shield, 28, wing 194, tail 73, tarsus 59. 
Immature.—Similar to adult. 
Nestling in down.—Wholly greenish-black ; bill coloured as in adult. 
Nest.—Open, constructed of grass, and placed on the ground among bushes, 
such as polygonums, etc., in a swamp situation. 
Eggs.—Clutch, five to seven; smooth and glossy in texture ; ground-colour pale 
green, minutely spotted over the entire surface with brown dots, with a few large, 
bold blotches of chestnut-brown, as well as paler underlying spots of a lavender-grey ; 
axis 43 to 46 mm., diameter 29 to 32. 
Breeding-season.—October to January or February ; July and August. 
Distribution and forms.—Confined to Australia. Three forms have been named, 
but on account of sporadic movements due to drought subspecies probably 
