178 GEOLOGICAL SURVEY OF THE TERRITORIES. 
seems to be produced over the extremities of the diapophyses of the 
first sacral vertebrae in Cathartes and the Condors. This border is car- 
ried backwards a certain distance to be lost in the true gluteal ridge, 
of which it is the anterior extension. It is less prominent in Gyparchus, 
as seen in a good life-size figure of the sternum of this Vulture given 
by Eyton in his Osteologia Aviwm. Posteriorly, and where the sacral 
vertebre are visible from above, the outline of the area they appropriate, 
is lozenge-shaped, the anterior angle being in the locality of the point 
where the ilio-neural canals terminate posteriorly in most birds; the 
posterior angle is in the last sacral vertebra, while the lateral angles are 
about opposite the acetabula, corresponding to the longest processes 
thrown out from the vertebra below as abutments at this important 
point. The last sacral vertebra, in all of the Cathartide, although well 
anchylosed with the one next beyond,is never completely grasped by 
the ilia, its transverse processes always projecting a little beyond. 
The gluteal ridges meet then at a point, mesiad, in such of these Vul- 
tures as we have described the ilia meeting at a greater or less distance 
beyond the antitrochanters, they diverge to form bounding lines to the 
post-acetabular region, being carried in their course above the antitro- 
chanters, in whose neighborhood they form lateral angles to be directed 
backwards, to terminate behind in the produced processes, or process on 
either side, of the ilium. Such part of the superior pelvic surface as is 
generally known as the pre-acetabular is carried or continued backwards 
to the space between the antitrochanter and the lateral angle of the 
gluteal ridge, on either side, consequently, for description’s sake, slightly 
back of the acetabulum. This well defined region is formed on each 
side by an iliac bone, and confining ourselves to one side, we find it to 
be concave from before, backwards, as well as from side to side, the 
general surface being smooth and its narrowest part just beyond the 
cotyloid ring. In the Condors, less so in the rest of the family, the 
posterior moiety looks almost directly outwards, only slightly upwards, 
while in all the outer side of the anterior portion is directly upwards, 
and the inner nearly as in the posterior half; in Cathartes all of the 
anterior portion looks directly upwards, this Vulture having a much 
flatter and broader pelvis generally than the others of the family. 
As among Hagles and many other diurnal Raptores, the posterior 
half of the pelvis of the Cathartide, as well as the Old World Vultures, 
is beni downwards from a vertical plane passing through the bone 
tangent to the anterior arcs of the ischiatic foramina; this causes the 
post-acetabular surface or region to face backwards and upwards, it 
being bounded anteriorly by the gluteal ridges, posteriorly by a rounded 
border concave inwards, composed of the iliac margins and the last 
sacral vertebra. 
The under side of the iliac surfaces, or such portions of them as are 
seen upon an inferior aspect, are in the horizontal plane anteriorly, 
and up to that point, as we proceed back wards to where the pleurapophyses 
and transverse processes of the first four or five vertebrae are thrown 
out to abut against and anchylose with them. The anterior face of the 
first sacral vertebra possesses all of the necessary elements to articulate 
with the last lumbar; its neural spine is quadrate and produced beyond 
the ossa innominata; the prezygapophyses look upwards and inwards; 
the entrance to the neural canal is elliptical with the major axis verti- 
cal. In all of the Cathartide the first sacral vertebra supports more or 
less of a well developed hypapophysis; this process is very large in our 
Specimen of Pseudogryphus, possessing lateral wings and upon its anterior 
face bearing a small facet for articulation, with a similar process upon the 
last dorsal. This plate-like hypap ophysis, merging with a more feebly 
