Genus— P URPUREICEPHALUS. 
Purpureicephalus Bonaparte, Rev. Mag. de Zool., Vol. VI., 
p. 153, 1854 . . . . . . . . . . . . Type P. spurius . 
Porphyreicephalus Reichenow, Vogelbild. Syst. Verz., p. 1, 
1883 . . . . . . . . . . . . . . Type P. spurius . 
Also spelt — 
Porphyrocephalus Heine, Nomencl. Mub. Hein., 241, 1890. 
Large Platycercine birds with very long projecting bills, long wings, very 
long wedge-shaped tails, small feet and peculiar coloration. 
The bill is the distinctive feature of this genus, ‘which is otherwise very 
similar to Barnardius. 
The bill is very long and projecting, with the tip very long and sharp : 
the whole bill very narrow and about three times as long as the depth at the 
base ; the under edge of the upper mandible bearing a distinct gap succeeding 
the long tip but thence almost straight to base : the under mandible deep and 
very narrow, the tip very long and the cutting edge straight ; the sides 
strongly sinuate. The cere is naked, the nostrils high up and circular in shape. 
The wing is long with the third primary longest, the second shorter, but 
longer than the fourth, the first and fifth shorter and about equal. The first 
primary is not emarginate on the outer web like the succeeding four. 
The tail is very long and composed of broadly elongate feathers : it is 
strongly wedge-shaped, but the middle four feathers are about equal, the 
two centre ones slightly longest. 
The feet are normal and small, but comparatively long and thin. The genus 
is monotypic and constitutes one of the very interesting phylogenetic studies 
in the Australian Psittaciform birds. It is rather obviously from colour pattern, 
a close ally to the Barnardius group, but with the evolution of few colour 
changes it has developed a most peculiar bill alteration. This is remarkable, 
as the bill seems little altered in Barnardius from Platycercus , though the 
colour change has been very great. 
It is rather peculiar in showing the dominance of the erythristic element, 
which is practically missing in Barnardius , while a counterpoise seems to 
have been reached between the erythristic and cyanistic elements, the latter 
dominating in Barnardius. Thus the immature is wholly green above with the 
under-surface tending in the cyanistic direction : the mature has the top of 
384 
