LECTURE VIII. 



209 



foreliead of the brown Cebiis. As regards the rest, the shape 

 of the cranial bones and the course of the sutures is the same 

 in both. 



On viewing the skull from the side, scarcely any differ- 

 ences are noticed excepting those mentioned. The posterior 

 projection of the temporal bone, which, so to speak, continues 



Pig. 79. Skull of Cebus albifrons, base. 



the zygomatic process, is less prominent in the brown Cebus, 

 but shows behind it a deeper depression than in the albifrons. 

 The zygomatic arch is higher and thinner in the brown Cebus ; 

 in the albifrons rounder and thicker. The skull of the albi- 

 frons is more equally arched, whilst it is somewhat depressed 

 in the middle in the brown Cebus ; in the latter the occipital 

 squama is nearly horizontal, in the former it inclines inwards. 



