204 LECTURE VIII. 



American continent inhabited by simious tribes, and exhibits 

 such a variety in foruij that it is difficult to distinguish the 

 different species merely by their external appearance. The 

 cebus presents in this respect difficulties not unlike those at- 

 tending the investigation of mankind, since every species ex- 

 hibits such a diversity in form, that by some they are considered 



Fig. 74. Skull of the brown Sajou (Ccbus apella), top view. 



as separate species, by others as varieties or races. It is, 

 however, our object not only to ascertain whether the cehtis 

 albifrons ( Weisstirnige Rollaffe) is only a variety of the common 

 Capuchin ape, or a separate species ; but also to discover by 

 what characters this species may be distinguished from, the 

 common brown sajou {cebus apella). That they belong to 

 different species is undoubted. The brown and the white 



