24 Osteology of Circus hudsonius. 
scapular process, we find on the side of the shaft a long shallow 
notch, which in life is spanned by a delicate ligament, thus con- 
verting the notch into a foramen. In many owls this foramen 
pierces the wing of the scapular process of the bone near the centre, 
as in .Sheotyto, where I found it transmitted a branch of that cervical 
nerve coming from between the twelfth and thirteenth cervical ver- 
tebree. (Osteology of Sfeotyto cunicularia hypog@a—Hayden’s 
t2th Annual. ) 
The scapular process of the coracoid has already been alluded to 
above when describing the scapula. It is comparatively very 
small and shows but little on direct inner view (Fig. 9). It 
holds the same position as seen in /dycter americanus, Micrastur 
semitorqualus, Buteo borealis and others studied by Ridgway, and 
so strikingly compared in his ‘‘Outlines of a Natural Arrange- 
ment of the Falconidee.’’ 
Upon the anterior aspect of the coracoid or really on the head 
of the bone, there is an elongated facet placed vertically and 
slightly raised above the surrounding parts, which articulates with 
a broad surface of similar form on the outer side of the expanded 
head of the clavical, this latter surface looks directly backwards, 
a special recess being made for it. ‘The meeting of the two 
bones is extensive and very intimate, as I have elsewhere 
pointed out. 
The. rounded tuberous head of the coracoid rises but little above 
the broad surface of the anterior end of the clavicle, and this pro- 
jection arches over a recess at its inner aspect in which is hidden 
large pneumatic foramina that communicate with the hollow shaft 
and other parts of the bone. 
The furcula or the united clavicles are likewise highly pneumatic 
bones ; the foramina that enter them being found upon the non- 
articulating surface, opposite the foramina just described as per- 
forating the inner side of the head of the coracoid. When the 
two bones are 27 sz/w, these two surfaces form the anterior walls of 
a fossa that lies immediately beyond the ‘‘tendinal canal’’ and 
really a part of the same enclosure. 
Above, the clavicles are broad and articulate with the sides of 
he heads of the coracoids, and the clavicular process of either 
scapula in a manner already described. Viewed from in front 
they present the extreme type of the U-shaped style of the bone, 
the internal periphery of the arch being nearly a semicircle. The 
