The humerus with its crests, ridges and processes, presents so many modifications characteristic of the various groups of birds, that its configuration alone is not only of considerable taxonomic value but that almost any genus, excepting, of course, those of Passeres, can be " spotted " by a close examination and comparison of this bone.
Many of the neighbouring mountain ridges have uniform crests, but a greater number terminate in numerous peaks, some sharp, rugged and rocky, but more of them rounded domes.
Outer walls of upper cheek-teeth W-shaped, and transverse crests oblique.
The upper cheek-teeth are short-crowned and without cement, and show distinct traces of the primitive tubercles; the two outer columns form a more or less complete external wall, connected with the inner ones by a pair of nearly straight transverse crests; and the premolars are originally simpler than the molars.
The first lower premolar compressed in front; the others composed of a single pair of transverse crests, with a small anterior and posterior basal ridge.