NATIVE HEN. 207 
indefinable; these are: M. v. ventralis (Gould) from West Australia ; M. v. whiter 
(Mathews) from Eastern Australia, smaller and browner with a more slender bill ; 
and M. v. territorii (Mathews) from Northern Territory, a still browner form. 
Genus TRIBONYX. 
Tribonyx Du Bus, Bull. Acad. Roy. Sci. Brux., Vol. VII., No. 4, April, p. 212, May 1840. 
Type (by monotypy): Tribonyx mortierit Du Bus. 
Brachyptrallus La Fresnaye, Revue Zool., Aug. 1840, p. 231, Sept. Type (by monotypy) : 
B. ralloides La Fres. = T. mortierii Du Bus. 
A degenerate form of the preceding, the whole bird of much heavier build, the 
bill larger, stouter, the nostrils more open, the frontal plate better indicated. The 
wing is absolutely shorter, and much more rounded, the first primary still long but 
scarcely longer than the tenth, while the second to the seventh are almost all the 
same length; the inner secondaries longer and the coverts disintegrated and 
encroaching over the secondaries. The tail longer, over half the length of the 
wing and is composed of sixteen very broad square-tipped feathers, a little softer 
than in the preceding, and the two outer feathers on each side shorter than the others, 
but otherwise the tail is quite square. The legs are long and very stout ; the tibia 
only exposed for a very little bit; the front of the tarsus covered with horizontal 
scutes, the hind edge with a similar indefinite row while the sides are reticulated 
with three or four rows of small hexagonal scales ; the toes are very stout, the 
middle toe little shorter than the tarsus and longer than the outer and inner, the 
former exceeding the latter ; the hind-toe is short and stout. 
Coloration the same as the preceding. 
These are obviously degenerate Moorhens, the island form being related to the 
mainland one exactly as Mantellornis is to Porphyrio; the same processes appear 
to have been followed in exactly the same way ; the isolated form growing larger 
and stouter, the wings rounder and flightless, the tail-feathers broader and softer, 
the legs shorter and stouter, and the toes stouter, the hind-toe also shortening and 
thickening ; all these changes taking place in the structural features and being 
accompanied by similar alterations internally while the coloration has remained 
unchanged. . 
143. Tribonyx mortierii—NATIVE HEN. 
Gould, Vol. VI., pl. 71 (pt. xxxr.), June Ist, 1848. Mathews, Vol. I., pt. 4, pl. 55, Aug. 9th, 
1911. 
Tribonyx mortierti Du Bus, Bull. Acad. Roy. Sci. Brux., Vol. VII., No. 4, April, p. 214 and 
pl., May 1840: Nouvelle Hollande = Tasmania. 
Brachyptrallus ralloides La Fresnaye, Revue Zool., Aug. 1840, p. 234, Sept.: Tasmania. 
Tribonyx gouldi Sclater, Ann. Mag. Nat. Hist., Ser. III., Vol. XX., p. 123, Aug. Ist, 
1867: Tasmania. 
DisTRIBUTION.—Tasmania. 
Adult male—General colour above warm brown, includng the head, hind-neck, 
back, upper tail-coverts, scapulars and innermost secondaries ; lesser wing-coverts 
slate-grey ; bastard-wing black, with pale outer webs and white tips; quills black 
with pale edges, the two outer primaries fringed with white at the tips ; tail-feathers 
black, with brown on the outer webs ; lores and feathers behind the eye and fore- 
part of cheeks brown, like the head, but slightly paler; throat, fore-neck and breast 
slate colour ; a tuft of black feathers, with broad white tips, on the sides of the 
body, giving the appearance of a lateral white patch ; lower flanks and thighs grey, 
minutely tipped with white ; middle of abdomen black, with minute white tips to 
the feathers ; under tail-coverts intense black ; under wing-coverts blackish, tipped 
