OSTEOLOGY OF BIRDS 



17 



Figures 17 and 18 exhibiting the method of articulation of the 

 bones of the shoulder girdle, holds good for all members of the 

 Cathartidae, and in them the clavicular head simply rests against the 

 inner side of the coracoidal capitulum, while on the other hand in 

 Neophron and in many of the Falconidae, if not in all of them, the 

 coracoid is actually molded upon the clavicular head, or perhaps it 

 had better be said, that the latter is accurately impressed by the head 

 of the coracoid with which it articulates, the articulation being very 

 close and intimate. As it is, it stands as another good character 

 pointing to the affinities of the Old World vultures and Falconidae, 

 as separated from the family now under consideration. 



Fig. iS 



Articulations of the bones of the shoulder girdle. (Outer aspect. Natural size) 

 Fig. 17 Cat h arista urubu. Natural size 



Fig. 18 Neophron percnopterus; natural size. Left lateral view in each 

 case; tt, os furcula; B, scapula; «, coracoid ,i■^--^^,^ 



Among the Cathartidae we find the sternum to be a bone that 

 varies somewhat in its form for the several genera of the family. 

 In the first place, it presents no distinct manuibrium as it does in 

 Neophron and in the Falconidae, this feature being supplanted by 

 a massive and tuberous promontory in the median line, over which 

 the broad concave corocoidal grooves meet at the middle point 

 above. From thence these grooves are produced shallower, nar- 

 rower, and less distinct to the deep pneumatic fossae that are found 

 upon either side, and which are situated just below the facet for the 

 first sternal rib on the costal border in all Cathartidae. The body 

 of the sternum is oblong and deeply concave, being wider -behind 

 than it is anteriorly, and longer for its width in Catharista than it 



