134 



SKETCH or THE HISTORY OF MAMMALIA. 



the skull of the fulvous paoa {Ccelogeuys fulvus), in pro- 

 file (Fis:. 85), and as viewed on its palatal aspect (Fig-. 

 86). The peculiarity in question is the immense deve- 

 lopment of the zygomatic arch, forming an expansive 

 shield of bone, almost concealing the lower jaw, rough 

 and convex externally, and deeply concave within. This 

 broad projecting convex plate has its concavity lined by 

 a continuation or reduplicature of the skin of the face, 

 constituting a sort of pouch, with a narrow linear opening 

 just below the angle of the mouth, and having its edges, 

 from which the pouch leads directly upwards, almost if 

 not quite destitute of hair. 



85.— Skull of Paca. 



Notwithstanding this narrow orifice, the sac or pouch 

 is so closed, that it cannot be serviceable as the recep- 

 tacle for ibod, for neither is the orifice dilatable, nor the 

 pouch, enclosed as the latter is within walls of unyielding 

 bone. The use of this sac is not ascertained : perhaps a 

 secretion of some kind may take place from the subzygo- 



