168 MR. W. K. PARKER ON THE OSTEOLOGY 
in the Guans (Penelope), as they do in some of the Pigeons; and beautiful crests, 
often crisped and curled in the most exquisite manner, are the rule in this group. The 
bones sometimes take more or less part in the ornamentation of the head; the face is 
enormously expanded into a bony tumulus in Ourar pauai; the “‘ cere” is more or less 
strengthened by an elevation of the subjacent bone in Crar; and the anterior frontal 
region is elevated to a great height, to form the ‘‘ horn” of Oreophasis. The skull in 
these birds, as in many others, is the great problem to the morphologist ; and on it we 
must be willing to bestow the most care and labour. 
On the whole, the degree of divergence from the Gallinaceous type in the structure 
of the Curassow’s skull is somewhat greater than what is seenin the Talegalla. The 
skull of Craw globicera reminds one more strongly of that of Tetrao wrogallus than that 
of the Turkey ; it is also manifestly columbine in many respects, but it does not strike 
me as being at all more related to the skull of a medium-sized Pigeon (e. g. Columba 
palumbus) than to that of one of the ‘‘ Musophagide” or Plantain-eaters, e.g. the 
Touraco (Corythaix buffoni). There is but little difference as to thickness in the 
skulls of the Turkey, Cock-of-the-Woods, and Curassow; but that of the first is 
dense and hard, like a Mammalian skull; that of the second is very coarsely spongy ; 
whilst the Curassow’s skull, although thick and heavy, is more ivory-like, and alto- 
gether comes nearer to the skull of a typical bird. The occipital plane forms a more 
obtuse angle with the basicranial axis than in the Fowl, whilst in the Turkey it forms 
a right angle, and in Tetrao urogallus an acute. The occipital plane is more rounded 
and smooth than in the Fowl, whilst in the Fowl it is much more so than in the gigantic 
Turkey. The condyle is perfectly typical. 
There is a falling-off in the breadth of the basitemporal region ; but the ear-drum is 
as hollow as in the Fowl. The great ‘“‘incus”’ has got a second head, not, however, 
very separate from the first. The temporal fossa is bridged over as in the Fowl-tribe 
generally, but the orbit is better formed ; it is evenly round for about three-fifths of a 
circle, and the massive frontals grow outwards into the supraorbital region, as in the 
larger Pigeons, so as to be flush at the edge with the lachrymal. ‘There is a shallow 
fossa between each convex frontal. The lachrymal, which is a flat, fatty bone in the 
Fowl, the Turkey, and the Grouse, is in the Curassow spongy and pneumatic ; and the 
descending process is also thick and expanded, coming close to the condition of the 
bone in the Screamers, Pigeons, and Plantain-eaters. The interorbital septum is perfect, 
but rather thin : in this it differs from Columba and Corythaix, and agrees with the large 
Galline proper; that partly depends, however, upon the large size of the bird. The 
antorbital and the ali-ethmoidal laminz are ossified at their roots; but the al of the 
septal and ali-nasal regions are, with all the upper part of the ‘‘ septum nasi,”’ wholly 
cartilaginous. The lower, outspread portion of the septum—that part which in all air- 
breathing Vertebrata tends in the embryo to enclose the air-tubes, and to make them 
into complete cartilaginous pipes—this broad base of the ethmo-vomerine cartilage is 
