THE BIRDS OF AUSTRALIA. 
distinct groups has remained constant, though the bills and crests have 
become widely differentiated, and no alteration whatever in coloration has 
taken place, the peculiar coloration and different wing formula demand generic 
recognition. We thus arrive at four generic groups in the White Cockatoos, 
and I see no course open save their recognition or the lumping of the whole 
under one genus name. The latter course would not be a scientific procedure 
as the skulls of Cacatoes and Licmetis appear to differ. The skull of Lophochroa 
(the pink-flushed species) would show just as great distinction, as superficially 
the bill differs more from that of Cacatoes than does that of Licmetis. It 
again becomes a matter of colour and it is quite impossible in these forms 
to admit colour only as of generic value. It is quite unreasonable to accept 
a structural^) difference in one case as of generic value and reject it in 
another. Again, as noted above, the structure of the bill differs in the 
pink-flushed species as compared with the white species. A further 
complication is the nature of the crests. Are these of less value than a 
mere elongation of the bill ? It is suggested that the osteology of the species 
will show characters just as strongly marked as the ones I superficially 
record. In which case there will be no hesitation in accepting the groups 
here utilised as genera, and to use them as such appears to be the only logical 
conclusion. 
A splendid instance of the newer and more exact methods of Ornithology 
is seen in a paper entitled “ Notes on Ptilosis, with special reference to 
the feathering of the Wing, by W. De. Witt. Miller,” in the Bull. Am. Mus. 
Nat. Hist., Vol. XXXIV., pp. 129-140, 1915. 
Dealing with first primary covert, he has written : “ The condition of 
this covert in the Psittaci is of particular interest, as I believe it will prove 
of some assistance in the difficult problem of classification in tins group. In 
the Cockatoos ( Cacatoes , Eolophus, Licmetis and Leptolophus) and in Stringops 
the first covert is normal in size, form, and texture. In all other Parrots 
examined it is decidedly less than three-fourths the length of the second, 
often less than one-half, and is sometimes reduced to a mere tuft of down, 
not one-third the second covert in length. Tins last stage is reached in 
Charmosyna , Ara , Conurus and Conuropsis , and the feather is nearly or quite 
as vestigial in Trichoglossus, Vini , Anodorhynchus , Brotogeris, Pionus, Pionites, 
Porcephalus , Psittacula and Myiopsitta. In Amazona, Rhynchopsitta, Psittacus , 
Palceornis, Agapornis, Aprosmictus ( Ptistes auct.), Alisterus ( Aprosmictus 
auct.), Tanygnathus and Melopsittacus the reduction is carried not quite so 
far, and in none of them is the covert completely downjx It is least reduced 
in Coracopsis, Pezoporus , Platycercus, Psephotus, Eos , Lorius and Nestor, 
being considerably more than half as long as the second, less vestigial in 
166 
