144 
GENUS PLYCTOLOPHUS. 
narrowed and acute, overhanging the lower mandi- 
ble; the tomia or cutting edges sinuated or toothed ; 
under mandible narrower than the upper ; the tongue 
thick, fleshy, and smooth ; nostrils lateral, in the cere 
at the base of the bill ; head crested, the crest com- 
posed of two rows of acuminate feathers, the tip di- 
rected forwards, and which can be erected or de- 
pressed at will ; cheeks plumed ; tail rather short, 
even ; plumage compact, the tips of the feathers 
rounded, truncate ; feet robust ; tarsi short and re- 
ticulated. 
The Cockatoos, so called from the usual call-note 
of the species, form a well marked genus, readily 
distinguished from the other groups of the Psittaci- 
da: by their light and uniform colour, which is white, 
or white tinged more or less, according to the species, 
with sulphur-yellow or rose-red, by their peculiar 
shaped crest, and by their short and even tail. The 
massive and powerful bill, as well as the robust scan- 
sorial feet of this section, evidently point to the si- 
tuation they hold in the family ; and, with the near- 
ly allied genus Calyptorynchus and some other forms 
which sustain theconnexion until more distant groups, 
they are considered as representing tbe Rasorial 
group of the family. They are natives of Australia 
and the Indian Isles, where they inhabit the woods 
and forests of these luxuriant climes. They feed 
upon the seeds of various trees and plants, being 
able, with their powerful bill, to break the stones of 
the hardest fruits. Their nidification is similar to 
