must bear a larger pattern than the sides (see the second diagram, Fig. 19), 

 which are seen against more distant ground or forest landscape, with details 

 reduced and altered by perspective ; and the highest portions of the side-planes, 

 e. g., the sides of the animal's head, being seen, in the long run, against the 

 most distant backgrounds, must have the finest pattern of all. Cooperant 

 with these principles is the fact that the pattern looks different on receding 

 planes of the solid object. Thus in the side view all that shows of the neces- 

 sarily coarser top-pattern is so refined and narrowed by perspective that it is 

 fully equivalent to the actually finer pattern of the sides. In the reverse case, 

 the side-pattern scarcely shows at all. 



Nature's achievement of this ultimate perfection of obliterative coloration, 

 on birds, is the subject of our next chapters. 



32 



