358 The Bird 



The great Order of perching birds {Passeres) shows to 

 what varied uses the typical foot can be put. All birds 

 of this Order have three toes in front and one behind, 

 and there is scarcely a place on the globe to which these 

 birds have not adapted themselves; and recently too, 

 as would seem probable from the similarity of the foot- 

 type running through all. 



This very foot holds much of interest too, if we con- 

 sider it from another point of view. Many apes and 

 monkeys, and we ourselves, still have the five fingers and 

 toes which we suppose was the number originally devel- 

 oped upon the limbs of the vertebrate prototype; while 

 horses and deer — animals much lower in the scale of 

 life — have had the five original digits reduced to one 

 or two. So among birds the ostriches and some other 

 low forms have become extremely specialized in the same 

 respect, possessing but two or three toes, while those 

 birds which in mental and physical attributes excel all 

 others of their Class are still more reptilian, and thus 

 more primitive — more Archseopteryx-like — in possessing a 

 larger number of digits — four. Thus when we speak 

 of an animal as high or low in the scale of life, we must 

 carefully distinguish between mere specialization and 

 actual upward progress, mentally or physically, toward 

 some ideal goal. The branch of a tree, which stretches 

 horizontally farthest from the parent trunk, is not likely 

 to be the one which reaches upward high enough to catch 

 the first raA'-s of the morning sun. 



The majority of the Passeres are arboreal and the 

 strength of the tiny tendons which run down the leg and 



