512 



ZOOLOGY 



SECT. 



s. oc 



ex.oc 



FIG. 1151. Skull of Ant-eater (Myrme- 

 cophaga), ventral view. Letters as in 

 Fig. 1150. In addition, b.oc. basi- 

 occipital ; glen, glenoid surface for 

 mandible ; pter. pterygoid. 



short and powerful, with well- 



Lc.f 



is broad and rounded ; the anterior 

 border unites with the coracoid 

 process so as to convert the 

 coraco-scapular notch into a fora- 

 men. In the middle of the spine 

 there is a triangular process : a 

 ridge on the post-spinous fossa pre- 

 sents the appearance of a second 

 spine. The fibres of origin of the 

 sub-scapularis muscle extend on to 

 the outer surface as far forward as 

 this ridge, so that the part of the 

 outer surface behind the ridge 

 corresponds to a part of the sub- 

 scapular fossa, which in other 

 Theria is co-extensive with the 

 inner surface. Except in Cycloturus 

 the clavicles are rudimentary. All 

 the carpal bones are distinct. 



In the Armadillos the scapula 

 (Fig. 1153) has an extremely 

 prolonged acromion (acr.), some- 

 times articulating with the humerus. 

 A ridge (sp r .) representing a second 

 spine is present. The clavicle is 

 well developed. The humerus is 

 developed processes and ridges, and 



S.OC 



FIG. 1152. Skull of Three-toed Sloth (Bradypus tridactyJus). Letters as in Fig. 1150. 



with a foramen above the inner condyle (entepicondylar foramen). 

 The carpus consists of the ordinary eight bones. 



