738 GEOLOGICAL SURVEY OF THE TERRITORIES. 
bone as one large opening (C. aura) or by a group of several smaller 
ones (C. atrata) at the outer extremities of their necks, just below the 
tubercula, anteriorly. We have just said that they occur in the free ribs 
of the cervical portion of the spine; this is indeed the case, but of very 
rare occurrence, and we may almost add in perfect safety the ribs of the 
sacral vertebre to the list of non-pneumatic bones of the Oathartide. 
The sternal ribs, at their inferior extremities, show like perforations, 
more commonly on their anterior aspects, though by no means do we 
always find them wanting on the posterior faces; more likely would 
we be disappointed in our search for them in the last sternal ribs; and 
we doubt of their ever occurring in the set that articulate with the first 
pair of sacral ribs. 
The osseous portion of the basin, completed by the parial pelvic bones, 
is not usually permeated by air as thoroughly as it might be; indeed, in 
all those parts of the pelvis where the component bones become plate- 
like in character or flatten out, this property is denied them, and it is 
only where ridges become thickened from any cause whatever or other 
prominences take place that we find pneumatic foramina present. 
Notably these localities are three in number: Externally, in the recess 
on either side, just below the angle formed by the deflection of the glu- 
teal ridge, and above the antetrochanter. Internally, in two places 
about the cotyloid ring at the extremities of its horizontal diameter 
slightly produced, at a greater or less distance from its periphery, and 
again at the base of the posterior concavity formed by the ilium and 
ischium, immediately within the rounded margin of the ischiatic fora- 
men. 
Ofthe Vultures, C. atrata seems to possess the most pneumatic sacrum, 
while that of C. aura is the least so. In Pseudogryphus the foramina 
are particularly well supplied, forming good-sized groups at all the 
localities just specified. They are absent in the last situation mentioned, 
in OC. aura, Sarcorhamphus, and C. atrata, but in the last species quite 
a cluster occurs in the ilium on its internal surface, well within the upper 
margin of the ischiatie foramen. 
The pectoral limb of the Cathartide is highly pneumatic from humerus 
to the last joint in manus, with the sole exception of the osseous core 
of the claw on the first digit. 
In the humerus the large pneumatic fossa, with the collection of 
smaller openings at its base on the anconal aspect of the head, is never 
absent; in all but awra a few additional ones are found at this extrem- 
ity of the bone, on the opposite side, just beyond the articular surface. 
At the distal end of humerus other openings occur of no mean size, 
especially in G. papa and C. atrata. These are generally situated on 
the anconal aspect of the bone, in a shallow but circumscribed depres- 
sion that is found there, beyond the tubercles for articulation; some- 
times a large one is found quite near the ulnar tubercle. 
The cubit and radius both have these little perforations well supplied 
them, especially about their proximal extremities, anconad; the number 
not being nearly so great at the other end of the bones. The two free 
earpal bones possess at least two or three of these foramina apiece, and 
we note on the anterior face of scapho-lunar in C. atrata two very siz- 
able ones, that seem quite constant for this species. 
In metacarpus, the bone is pierced by a single foramen just beyond 
oS magnum, at the point where index and medius metacarpals joined in 
the growing bird. Other perforations are found about both extremities 
of this segment in the angles and recesses formed by the conforma- 
tion given it by the amalgamation of second and third metacarpals. 
