178 THE GENERAL ANATOMY OF GORILLA [SECT. A 



The scapula contrasts strongly with that of Man in respect 

 of the large extent of the supra-spinous fossa. The scapula other- 

 wise resembles the human scapula more closely than do those of 

 the Chimpanzee and the Orang-utan. Paradoxically, the clavicle 

 is comparatively weak and slender, lacking as it does the massive 

 character of its representative m the Orang-utan. The humerus 

 is characterized by a similar lack of definition as regards the 

 evidence it bears of the attachment of muscles and ligaments : 

 thus the deltoid muscle makes but little impression on the shaft, 



Tibia | \' '" 'f/ P # Fibula 



Fig. 119. Posterior aspect of the knee-joint of a young Gorilla (right limb), 

 shewing the annular form of the external articular cartilage. 



which indicates the relatively small size and functional activity of 

 this muscle in the Gorilla. The average figure representative of 

 the angle of torsion of the humeral shaft is given by Broca as 141°, 

 European Hominidae providing an average of 161°. 



The olecranon fossa of the ulna is very frequently perforated 

 (in about 80% of examples). The shafts of the radius and ulna 

 are not so straight as in the corresponding human bones, and 

 consequently the intermediate space is more extensive. In the 

 carpus, the ossa centrale and radiale fuse as in Man (unlike their 



