No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 139 



quently termed the shon\der-hlade, but how much more blade-like is the 

 scapula in this Lark and many other birds, as far as shape is concerned. 

 It is truly a miniature bony cimeter in Uremopliila. This is not true for 

 scapulae of all birds, hov^ever, for no one would ever be struck by such a 

 resemblance while regarding the J-shaped scapula of Colaptes mexicanuSy 

 or the straight, almost square-cut bone in some of our natatorial birds. 



In the Horned Lark the scapula is pointed and obliquely truncate 

 behind for more than a third of its slightly dilated posterior portion, on 

 the side towards the vertebrae. 



The outer border is reenforced by a rounded ridge for nearly its en- 

 tire length, while the inner is quite sharp. 



The blade becomes stouter and subcompressed as we near the gle- 

 noidal process ; this broad tuberosity extends downwards, forwards, and 

 outwards, and is crowned on its entire summit by a curved, subcircular, 

 articular facet, that supplies rather more than one-third of the glenoid 

 cavity for the head of the os humeri. 



The acromial ])rocess is bifurcated, and the clavicular head rests in the 

 fork. The larger bifurcation is the lower, and both rest against the 

 coracoid, on the inside and just below the head, creating the usual 

 scapulo-coracoid foramen, which in this case is not very extensive. 



The scapula is iDueumatic, and the foramina are to be found at the ex- 

 tremity of the larger bifurcation of the acromial process, and in the notch 

 between the two. 



The coracoid can boast of a very fair subcylindrical shaft between its 

 head and inferior expansion. This flared extremity is quite thin out- 

 wardly, stouter within, where it appears to be more of an extension and 

 spreading of the shaft in its course downwards. Below there is a nar- 

 row crescentic facet for the sternum, and at the upper edge of the exterior 

 and thin side of the dilated end we find a notch, sometimes a foramen,, 

 that appears to be constant. 



The upper extremity of the coracoid is an irregular tuberosity, con- 

 sisting of a lower, inner, and smaller process for articulation with the 

 clavicle, and an upper, superiorly convex head, that curls over mesiad to 

 create a fossa, at the base of which we discover a group of various-sized 

 IDueumatic foramina. Anteriorly the head shows rather a well-marked 

 process, into which the ligament coming from the horn of the sternal 

 manubrium, of the same side, is inserted. 



To the outer aspect, and below the head, is the reniform and vertical 

 facet that, with the scapula and os humero-scapulare, goes to complete 

 the glenoid cavity. 



The OS humero-scapulare is a free bone, rather larger than the patella^ 

 found at the upper and i^osterior angle of the glenoidal process of the 

 scapula. It is an elliptical disc, with a peg-like process extending from 

 it from behind. The outer surface is concave and articular for the com- 

 pletion of the glenoid cavity. This ossicle is held in position by various 

 fibrous ligaments stretching from its borders to the scapular arch and 

 the humerus. 



