4 NATURAL HISTORY ESSAYS 



all the baboons. Ugly, powerful, and ferocious, it 

 differs from its cousin in the greater inflation of the 

 cheeks, which are elevated into a series of rib-like 

 sculptures: in the adult these are brilliant with ultra- 

 marine, and separated by grooves of deep purple. 

 The pig-like snout is truncated in shape and scarlet 

 in colour, and the middle area of the face is also of 

 this hue. The beard and whiskers are orange 

 yellow, the ears bluish black, and the body fur 

 blackish olive. Female specimens have the face 

 blue only, without any purple, and even the males 

 do not assume the scarlet on the face till they have 

 cut their permanent teeth. In very young males the 

 face is merely dull purple like a dried raisin, and the 

 whiskers and beard are brownish yellow. A long 

 series twenty living specimens was recently 

 examined by the writer. Carefully worked out, the 

 chief differences between the two appear to be : 



DRILL. MANDRILL. 



1. Prominences on cheek Prominences ribbed and 



fusiform, smooth. deeply grooved. 



2. No distinct beard. Beard distinct and 



pointed. 



3. Colour of face purplish Colour ultramarine with 



black. purple grooves. 



4. Whiskers greenish grey Whiskers orange yel- 



like adjacent fur. low. 



5. Fur on chest greenish Fur dull white. 



black. 



