The distribution of Australian land birds

Previously I indicated the Geographical Distribution of Passerine Birds in Australia, and what appeared to me to be the directions of their expansion over the Continent.
The numerals (1 to 9) were placed upon those portions of the map which I considered to be the natural avifaunal areas. Had I then realised the order in which they spread over the Continent I should have placed 1 where 8 is, 2 where 1 is, and 8 where 7 is now, and so on, for convenience sake.
At that time, when dealing with the Passeres alone, the area 2 was strongest in species and area 3 in genera.
I expressed the opinion that the Passerine birds of area 2 had their origin in the old Papuan sub-region, and that the greater part of the remaining Passerine birds of Australia was derived from this area, travelling along three routes—from the N.E. to the W., from the N.E. to the S.E., and from the S.E. to the S.W. of the Continent The present-day parrots do not lend themselves to any of these lines of expansion, a recent evolutionary centre appearing to have been in area 7. Taking for example the large genus, Neophema, we find the line 2, I, 8 unrepresented, and with only a single species in area 9, as the tip of the western wing.