Page:The Emu volume 21.djvu/90

 and N.W. Cape districts) as being of a typical bird in good plumage, and I can assure Mr. Whitlock that I did not, in any way "make up" the skin for the special purpose, but I hope, and think, that the well-executed plate answered the purpose for which it was made. In my paper in The Ibis, October, 1917, referring to the above, I stated on page 592—"Much depends, too, on the making of a skin, as to whether these white feathers show or not." Apteria occur in practically all birds, to a greater or less extent, but in the ordinary way are concealed by the overlapping feathers, which need displacing, or uplifting, before the apteria are visible. Mr. Milligan made some interesting notes on the "white wing-patches" of M. cyanotus, v. leuconotus, in The Emu, v. l., p 52. There is no doubt but that the extent of the white feathers varies considerably, according to variations in the seasonal plumage, moulting, and probably also individually.

Page 183. Referring to the Grass-Wrens (Amytornis textilis and D. carteri), Mr. Whitlock says: "It is hard to conceive that the Dirk Hartog birds should show any but the slightest differences from the type obtained a few miles away."

I admit that one specimen was not much material upon which to work, and form an opinion, but the above statement is a sweeping one, and it is quite evident that those "few miles" of sea water are enough to prevent Malurus leucopterus and leuconotus and also Acanthiza from crossing it; so why not Amytornis, which is a bird of (apparently) feeble flight, using its legs more than its wings. As a matter of fact, the narrowest part of the South Passage, between the south end of Dirk Hartog and the mainland (Edel Land) is barely one mile wide, yet I found Shrike Thrushes (Colluricincla) and Babblers (Pomatostomus) in Edel Land, and Wedgebills (Sphenostoma) and Babblers on the Peron Peninsula, and none of these three species were found on Dirk Hartog by Mr. Whitlock or myself.

Even the Dirk Hartog Crow (Corvus) appears to be distinct from the mainland form.

The channel between Bernier and Dorre Islands is also about one mile in width, yet I believe, so far as is yet known, Dorre Island can claim a distinct sub-species in Calamanthus dorrei (which is very similar to the Dirk Hartog bird) and Bernier Island has a good sub-species in Maluris bernieri, and another in Sericornis balstoni. Other similar instances might be quoted if space permitted, including the most remarkable case of the distribution of birds in the Canary Islands, where live welldefined sub-species of Frim/illcr (Blue Chaffinches) occur in the western group of these islands, all five of the islands being within sight of each other (vide Mr. D. A. Bannerman's paper. The Ibis. July. 1920, with coloured plates).