NATIVE HEN. 207 



indefinable ; these are : M. v. ventralis (Gould) from West Australia ; M. v. whitei 

 (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 mortierii 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., pi. 71 (pt. xxxi.), June 1st, 1848. Mathews, Vol. I., pt. 4, pi. 55, Aug. 9th, 

 1911. 



Tribonyx mortierii Du Bus, Bull. Acad. Roy. Sci. Brux., Vol. VII., No. 4, April, p. 214 and 

 pi., 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. 1st, 

 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 -co verts intense black ; under wing-coverts blackish, tipped 



