SHUFELDT. ] OSTEOLOGY OF THE CATHARTIDZA. 749 
condyle is fully as large as in our specimen of Aquila canadensis ; indeed, 
as a rule it seems to be larger throughout the Vultures than in the 
Falconide. 
In Polyborus tharus it is completely sessile and hemispheroidal in 
form, being still smaller, and in the Crows and Jays we know it is com- 
paratively still more diminutive. The area that includes the foramen 
magnum and the occipital condyle, and is bounded laterally by the ele- 
vated aural ridges, is depressed below the surrounding points in the 
basi-cranii of all of the Cathartide. In this space on either side we dis- 
cover the usual venous and nervous foramina, the precondyloid foramina, 
and those for the vagus and jugulars, the latter group occupying the 
base of a special depression for themselves. 
We find in many birds, beyond the condyle, on either side, a descend- 
ing tuberous process; they show pretty well in a fine specimen of the 
Canada Goose that we have at hand, while they are entirely absent in 
our skull of Circus, and only moderately developed among the Eagles. 
In the Cathartide, however, this pair of processes become the leading 
feature of the base of the cranium, though it must be remarked that they 
are not always equally well developed, for we have crania of C. atrata 
in our possession in which one would hardly be struck by them as 
worthy of particular notice. In one of our skulls of S. gryphus, however, 
and another of the Californian Vulture, these processes are remarkably 
well developed, being great tuberous projections that spring from ex- 
tensive bases, taking a direction downwards, outwards, and a little back- 
wards. Their inferior extremities seem to be designed for muscular and 
ligamentous attachment. In the accompanying cut, Sp designates this 
pair of processes, and Tp 
a quadrate bone. This fig- 
ure is life-size from the 
smaller skull of the two 
specimens we have of our 
Californian Vulture; it 
illustrates many of the 
points that we have just 
passed over in our descrip- 
tion of this view of the cra- 
nium. These basal pro- 
cesses form the outer angles 
of an isosceles triangle, the 
apex of which is the lip 
beneath the Eustachian 
tubes (Plate XXII, fig. 120, 
CG. aura), and the sides, the Rear view of cranium of Psewdogryphus californianus. 
lateral portion of the basi-cranii. The Eustachian tubes open at their 
usual site in one capacious common aperture, the gutter leading from 
the entrance of which is seen on the basi-pre-sphenoid. These tubes are. 
conical, the apices being at the anterior opening; it is not uncommon in 
C. aura to find these passages not closed in by the anterior bony wall, 
and the general aperture is quite wide in Pseudogryphus. The foramina 
for the passage of the carotids are found near at hand inthe recess. On 
either side of the Kustachian groove, jutting from the base of the sphe- 
noidal rostrum, we observe the pterapophysial processes; they are 
directed forwards, outwards, and a little downwards, each being crowned 
by an elliptical facette, the major axis of which in each case is nearly in 
the horizontal plane. We have already dwelt upon the fact as to how 
these apophyses meet and articulate with the pterygoids. They are 
