PSITTACIFORMES. 
into several genera, and had recently determined to separate Leptolopus 
(= Calopsittacus ) from the Cockatoos and place it near the Platycercine species. 
Further, Thompson has shown: “The Australian genera Pohytelis , 
Aprosmictus, and Pyrrhulopsis (and I expect Ptistes also) agree so perfectly 
in cranial characters with the Platycercince, that I do not doubt for a moment 
the necessity of removing them from the Palceornithince and uniting them 
with the other Australian genera.” The character for their divorce by 
Salvadori was the presence of a well-developed furcula. 
Dealing with Calopsittacus again, Thompson concluded : “On the whole 
I should say that, so far as cranial osteology goes, the position of Calopsittacus 
is an open question, and that it is by no means impossible that it may really 
deserve to be grouped somewhere near Nymphicus and Melopsittacus. While 
the facts suggest at least the possibility of a closer affinity than that usually 
recognised between the two Australian groups of Cacatuince and Platycercince, 
this larger question must also remain for the meantime in uncertainty.” 
The examination of the Australian Parrots alone, from an osteological 
view-point, would seem to be worthy of consideration, especially in view of 
such forms as Calopsittacus and Melopsittacus, while Pezoporus and Geo - 
psittacus were not available to Thompson, and the last named may never be 
now. 
However, judging from the superficial features and also accepting the 
anatomical facts known, I am separating Leptolophus, and as it is so peculiar 
I am giving it family rank. Also, as Probosciger (— Microglossus ) proves to 
be as distinct internally as it is externally, I promote it to family rank. 
The Black Cockatoos must be separated from the White Cockatoos, at 
least, as a subfamily, though it is suggested that family rank will later be 
granted them. 
To emphasize the development of the furcula in Pohytelis, qtc., these 
species are grouped together as a family, distinct from the Platy cere idee, 
though it is obvious they are very closely related. Unhesitatingly I separate 
Pezoporus and Geopsittacus from the Platycercidae and I associate with them 
Melopsittacus. It is interesting to observe that the cranial features of the 
last-named genus are very peculiar, as externally it differs considerably 
from the other small Australian species. I suggest that Pezoporus and 
Geopsittacus, as has been often advocated, are close relations of Strigops, and 
that Melopsittacus is a recent evolution product. That is, I believe Pezoporus 
and Geopsittacus to be remnants of a very ancient fauna, and that Melopsittacus 
has survived and, adapting itself to new environmental stresses, has become 
a strong living independent form, whereas the unadaptable Pezoporus and 
Geopsittacus have become nearly extinct phases. 
7 
