SHUFELDT. ] OSTEOLOGY OF THE CATHARTIDA. T51 
its posterior wall being as high as the anterior, and the cavity having a 
depth of three or four millimeters or more. In our specimen of C. atrata, 
an elliptical perforation exists in its hinder wall near the bottom; the 
carotids seem to invariably pierce its base within, by two openings. 
Immediately above and anterior to it we find the optic and other 
nervous foramina spoken of when engaged with the orbital cavities. 
Passing to the rhinencepalic fossa, we are not disappointed in finding 
that this cavity is also equally spacious and well developed, and lodging 
as it does, the encephalic lobe that presides over the sense of smell, “this 
fact becomes particularly interesting, insomuch that it may indicate 
extraordinary powers on the part of this faculty. The orifices of exit 
for the olfactory nerves are double in the Cathartidw, which is an excep- 
tion to the generalrule. Professor Owen found the same state of affairs 
in a Vulture that he dissected, and this able anatomist made this re- 
mark upon what he observed: ‘In the Vulture the olfactory nerve 
is single on each side, and continued from an olfactory ganglion or 
‘“‘rhinencephalon” along the upper part of the interorbital space to be 
distributed upon an upper and middle turbinal, the latter being the 
largest.”—(Anat. of Verts., Vol. II, pp. 123.) 
Along the roof of the cranial cavity, in the median line, the “longi- 
tudinal crest” is seen to pass. This may become grooved as it approaches 
its anterior termination, or for its anterior half, which indeed is the 
case in the majority of these birds; the groove dilating, and the whole 
merging into the general surface immediately before arriving at the 
conical rhinencephalic recess just referred to above. 
Fig. 115, in Plate X XI, gives us a very accurate idea of the hyoid arch, 
taken from an adult specimen of Cathartes aura. Like the other subjects 
presented the reader, it is life size; in it we notice that the glossohyal 
remains in cartilage during the life of this Vulture, and that the cerato- 
hyals, as two slightly curved, elliptical osseous plates imbedded in it at 
its base, articulate by the margins of their posterior ares with facettes 
on the anterior aspect of the basihyal; they are also tangent to each 
other at their middie points in the median line. In its turn, the basi- 
hyal seems to share largely the requisite support for the broad fleshy 
tongue in this bird; to do this, it has been given an extensive horizontai 
plate that is further strengthened by a keel below. This horizontal 
plate is concave above, dilated at its extremities, more so at the poste- 
rior one, where it produces a rounded process, mesiad, that is continuous 
with the carina beneath. This keel is deepest behind, sloping gradu- 
ally to the anterior part, where it merges into the horizontal plate and 
the thickened, elliptical facettes for the ceratohyals. Posteriorly, it is 
produced downwards as a long, slender apophysis, terminating in car- 
tilage, that no doubt represents the connate urohyal. At the sides of 
this keel, opposite its deepest part, there are, on either lateral aspect, 
cup- shaped depressions to receive the expanded heads of the hypo- 
branchial elements of the thyrohyals that articulate there. These latter 
are found to be two rather robust, long bones, with upturned and eylin- 
drical shafts, that articulate in their turn with the az.cerior heads of the 
ceratobranchial elements behind them. The ceratobranchials are still 
more curved than their stouter companions, and gradually taper off to 
cartilage-tipped points posteriorly. 
In contradistinction to theFalconide and the Old World Vultures, the 
members of this family are armed with much more powerful lower max- 
ile, this increased strength lies principally in the greater depth of their 
rami and consequent breadth of the symphysis, as well as the ponder- 
ous articular extremities, that these jaws possess. 
