OSTEOLOGY OF BIRDS 



121 



This process near its middle is pierced by the usual foramen, 

 and it lies well within the mesial margin. Although quite a stout 

 bone, a scapula is much compressed 

 in the vertical direction, even to in- 

 clude the head. Its blade is rather 

 broad, and the posterior third some- 

 what expanded, slightly curved 

 outward, to be at last drawn out 

 narrower to terminate in a blunt 

 point at the distal apex. Os fur- 

 cula and scapula seem to be very 

 moderately pneumatic. At the 

 shoulder joint we find present a 

 small os humero scapularc. 



Next in order we shall examine 

 the sternum of Pandion, and we 

 find it to be furnished with a very 

 ample keel which is convexed along 

 its lower border, concaved in front, 

 with handsomely rounded carinal 

 angle, and the whole extending to 

 near the posterior sternal margin 

 behind. Xiphosternum is but once 

 shallowly notched upon either side 

 of this keel, while anteriorly' we ob- 

 serve that the coracoidal grooves 

 decussate to some extent behind 

 the somewhat stumpy manubrium. 

 Upon the whole, the body of the 

 bone presents a great concavity for 

 its dorsal aspect, the sides being of 

 unusual hight. On a costal border 

 we find the process of that name in 

 front, Very small. Six facets oc- 

 cupy the anterior moiety of this 

 border, its posterior half being 

 sharp and thin. Adown the ante- 

 rior half of the middle line of the 

 dorsal aspect occur many pneumatic 

 foramina, and these diminutive 

 openings are also present in the oblong pits between the haemapo- 

 physial facets on the costal borders, and on the outer sides of the 



Fig. 6 i Right humerus of Pan- 

 dion, seen upon anconal view. 

 Natural size 



