76 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



the blade is divided into two parts by a prominent ridge, 

 the spine, which typically ends below in a more or less con- 



Fig. 20.— LeftscapulaofWolf. 

 si., glenoid cavity. u.,cora- 

 coid. ac., aciomion. sp. 

 spine. 



Fig. 21. — Left scapula of Horse. 

 This figure is much more reducfe# • 



than Fig. 20. 



as' 



spicuous projection, the acromion, which may, however, be 

 absent, its prominence being, generally speaking, correlated 



with the presence of the 

 collar bone. A hook-like 

 process, the coracoid, rises 

 from the antero-internal 

 side of the glenoid cavity 

 and varies greatly in size 

 in the different groups of 

 mammals; though it usu- 

 ally appears to be merely a 

 process of the scapula, with 

 which it is indistinguish- 

 ably fused, yet its development shows it to be a separate ele- 

 ment and in the lowest mammals (Prototheria), as in the rep- 



FiG. 22. — Left scapula of Man in position of 

 walking on all fours. Letters as in Fig. 20. 



