Page:The Emu volume 3.djvu/117

 one of the Museum collectors on the Cane and Ashburton Rivers, North-Western Australia, and which bore, at first sight, a striking resemblance to Gymnorhina tibicen (Latham) of Eastern Australia, except for their conspicuously long and narrow bills.

A closer examination and comparisons with a pair of mounted specimens of Gymnorhina tibicen in the Museum and with recorded scientific descriptions of that species disclosed so many points of difference as to warrant the separation of the Western form, and I therefore declare it a new species. My grounds for separation are briefly as follow:—(a) The Western bird is longer; (b) its bill is longer, more narrow, less arched, and more triangular-shaped; (c) its tail is shorter; (d) its tarsi are shorter; and (e) the thigh feathers are not black, but wholly white for the upper portion, and noticeably so for the lower. In addition, the plumage generally does not present the striking and decided contrasts of glossy bluish-black and snowy-white that mark the Eastern forms.

In support of the first ground of separation, I find that the measurements of the skins of the two oldest birds of the new species (one from the Cane River and the other from the Ashburton River) are respectively 15.5 and 16.6 inches, while those given by various authorities vary from 15 to 15.75 inches. As regards the second ground, the measurements of the culmen of the same two skins are 2.4 and 2.5 inches and in the three others (all young birds) the measurements of the same organ are 2.25, 2.25, and 2.1 inches, while the recorded measurements of Gymnorhina tibicen are given by one trustworthy authority as 2.1 and 2.2 inches, and by another as 2 inches in the male and 1.7 inches in the female. The culmen of each of the mounted specimens in the Museum measures 1 .9 inches. The girth of the mandibles taken at the forehead is 2.25 inches in the new species, and 2.5 in the mounted specimens referred to. In the former, too, the arch of the upper mandible is almost inappreciable, and the contour lines of the upper and lower mandibles form together an acute-angled triangle, or nearly so. On the third ground, the tails of the five skins of the Western form measure 5.1, 5.4, 5.5, 5.6, and 5.6 inches, while the authorities mentioned give those of Gymnorhina tibicen as 6, 6, 6.5, and 6.8 inches. On the fourth ground, the measurements of the tarsi belonging to the same five skins are 2, 2.1, 2, 2, and 2.1 inches, while the measurements recorded in the British Museum "Catalogue" are given as 2.3 and 2.4 inches. Respecting the fifth ground, the feathers of the upper half of the thighs of the one adult male are pure white, and of the lower half some are white, others white with brownish margins, and others brown with white margins. In a slightly younger bird the upper half is white, as also the whole of the opposed inner sides, while the outer sides of the lower half are blackish-brown with white tips. In all the three young birds the thighs are