152 GEOLOGICAL SURVEY OF THE TERRITORIES. 
The vacuity, forming such a characteristic feature on the sides of the 
jaw in so many of the class, is here rarely or never present. In 
Pseudogryphus its location is merely indicated by a shallow slit, that 
does not penetrate to the bone, though in G. papa it does for a limited 
distance along the base of a similar slit, but in our specimen of S. 
gryphus every trace of the locality of the foramen has been obliterated; 
again in Cathartes and Catharista narrow and faint groovelets are the 
sole indicators of its position, or the margins of the elements that origin- 
ally bounded it. 
Deep pits are found in the centers of the upper surfaces of the articu- 
lar ends; these are bounded externally by narrow, longitudinal facets, 
as do the inturned conical processes support more irregular ones. In 
the Californian Condor there is a predisposition to develop from these 
articular ends quadrate apophyses behind, in weak imitation of the 
spur-like affairs that we found so characteristic of the Tetraonide; this 
effort does not seem to be so thoroughly entered into by the others. 
The under surface of either articular end is divided into two by a longi- 
tudinal ridge, continuous with the lower ramal border; of these two 
surfaces the lesser and outer faces outwards and downwards, while the 
inner and larger faces downwards and towards the median plane. 
Almost an unbroken smoothness characterizes the internal and ex- 
ternal surfaces of the sides of the jaw; this is extended to the entire 
dentary region beyond. Even the ramal borders bounding these sur- 
faces above and below are notorious for the nice manner in which they 
are evenly rounded off, there being, scarcely any evidences of the 
coranoidal projections to interrupt this general smoothness; it is only 
in the superior one, that for its anterior third on either side, and as it 
sweeps around the curve of the symphysis, that it becomes sharp, to 
correspond with the tomial edges of the mandible above. 
The depth of the symphysis in Pseudogryphus is about two centimeters, 
and the deepest part of the jaw, the ramus just beyond the articular 
ends, is 1} centimeters; for aura and atrata the measurements are equal. 
The curve that is continuous with the lower ramal borders, limiting the 
symphysis posteriorly, is parabolic in outline. Viewing the mandible 
in the Cathartide from a lateral aspect, when it has been articulated 
with the cranium, we observe that it is bent downwards from a point a 
a little posterior to the distal end of the maxillary, from which point it 
is obliged to accommodate itself with the superior mandible. A row of 
foramina is always present just within the sharp edge of the superior 
border beyond, and still within these a few others are scattered about; 
one or two isolated, though parial, nutrient and vascular foramina are 
found at corresponding points, along the sides of the mandibles of all 
these Vultures. 
Having now passed, and we trust with sufficient thoroughness, over 
the osteology of the vulturine skull in general, and the osseous portions 
of its sense organs, may it not be in place and an advantage tous to ask 
the question here, Where have we detected any differences among these 
birds, so far as we have carried the subject? To present, or really to re- 
capitulate, these for our reader, we will here arrange the most prominent 
departures among the species in a tabulated form, or at least such of 
them as we deem worthy of reconsideration. This method we shall 
follow, after the discussion of each of the parts or divisions of the axial 
skeleton or its appendages that may be thus separated, grouping as 
much as we can into one table, without jeopardizing its utility, defer- 
Ting, however, general conclusions and comparisons for the concluding 
paragraphs of this monograph. 
