1900.] SHUFELDT—OSTEOLOGY OF THE STRIGES. 699 
being beneath the third sternal rib at its point of meeting the cos- 
tal border; it is compressed from before backward. The articu- 
lar facet, looking downward, backward and a little inward, is 
transversely concave, with a slight dividing ridge running antero- 
posteriorly, converting the general concavity into two smaller 
ones. The coracoid, when in position, is produced upward, for- 
ward and outward, making, with the verticai line through its 
base, rather an acute angle. A limited portion of the middle 
third of the bone only is subelliptical on section and at all shaft- 
like, due to the fact that the coracoid in this bird being perhaps 
less than the average length as compared with the size of the bird, 
and, secondly, to the unusually enlarged extremities, features 
observable, more or less, in Raftores generally. The anterior 
groove of the upper extremity, that is arched over by the head of 
the clavicle above, is deep and occupies fully the upper third of 
the bone. The coraco-clavicular process springs, thin and com- 
pressed, from the inner side of the shaft of the bone, at junction 
of upper and middle thirds, to turn upon itself, so as to be pro- 
jected upward, forward and a little outward, terminating with 
an elliptical facet for articulation with the clavicle. The upper 
border of this process is concave lengthwise and articulates 
throughout its extent with the inferior margin of the acromial 
process of the scapula. The lower and thin edge of the coraco- 
clavicular process tends obliquely downward, to be lost on the 
inner surface of the shaft of the bone near its middle. The outer 
wall of the anterior groove is formed by the coracoid itself, the 
process just described being really nothing more than a wing-like 
extension forming the inner boundary of the groove in this bird ; 
it terminates above both clavicle and scapula in a rounded tuber- 
ous head. Below this head, anteriorly and still more inwardly, the 
coracoid affords a vertical, elongated facet for the clavicle, while 
behind, looking a little outward, is the concave elliptical facet that 
constitutes about one-third of the glenoid cavity for the humerus. 
Internal to this last, and running first directly upward, then mak- 
inga right angle and continuing forward, a little upward and out- 
ward, the last direction being the upper margin of the coraco- 
clavicular process, is another facet, for the scapula. Behind and 
below, this bone displays one or two lines and depressions, bounda- 
ties of muscular attachments. In the middle of the anterior 
groove, opposite the base of the coraco-clavicular process, the 
PROC. AMER. PHILOS. SOC. XXXIX. 164. TT. PRINTED JAN. 19, 1901. 
