^0.4.] SHUFELDT ON THE OSTEOLOGY OF SPEOTYTO. 107 



the opposite side in tlie groove. This extremity is broad, its outer 

 angle being beneath the third sternal rib at its point of meeting the 

 costal border ; it is compressed from before backwards. The articular 

 facet, looking downwards, backwards, and a little inwards, is trans- 

 versely concave, with a slight dividing ridge, running antero-posteriorly^ 

 converting the general concavity into two smaller ones. The coracoid 

 when in position is produced upwards, forwards, and outwards, making^ 

 with the vertical line through its base, rather an acute angle. A limited 

 portion of the middle third of the bone only is subelliptieal on section 

 and at all shaft-like, due to the fact that tlie coracoid in this bird 

 being i)erhaps less than the average length as compared with the 

 size of the bird, and, secondlj^, to the unusually enlarged extremities^ 

 features observable, more or less, in Raptores 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 compressed, 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 projected upwards, forwards, and 

 a little outwards, 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 acro- 

 mial process of the scapula. The lower and thin edge of the coraco- 

 clavicular process tends obliquely downwards, 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 de- 

 scribed 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, tuberous head. Below this head, an- 

 teriorly and still more inwardly, the coracoid affords a vertical, elongated 

 facet for the clavicle, while behind, looking a little outward, is the con- 

 cave elliptical facet that constitutes about one-third of the glenoid cav- 

 ity for the humerus, internal to which, and running first directly up- 

 wards, then making a right angle and continuing forwards, a little up- 

 wards, and outwards, the last direction being the upper margin of the 

 coraco-clavicular process, is another facet, for the scapula. Behind and 

 below, this bone displaj's one or two lines and depressions, boundaries 

 of muscular attachments. In the middle of the anterior groove, oppo- 

 site the base of the coraco-clavicular process, the shaft of the bone is- 

 perforated ; this perforation is elhptical lengthwise with the shaft, and 

 passes directly through to make its appearance on the posterior convex 

 surface just below the scapula. This foramen transmits a branch of 

 that cervical nerve coming from between the twelfth and thirteenth 

 cervical vertebra^. This nerve branch, after passing through the bone, 

 is distributed to the under surface of the pectoralis minor nuTsele, and 

 its filaments ascend among its fibres. This foramen is observable also 

 in other Owls, as Buho virginianus, and in some of the diurnal Raptores^ 



