ANKLE AND FOOT 



than that of mammals, and the older authors saw in 

 this physiological likeness a reason for associating 

 together birds and mammals. Every fact of structure, 

 however, contradicts such an association, which is now- 

 adays held by no one acquainted with the facts. But, 

 on the other hand, the nearness of the sprightly, intelli- 

 gent bird to the sullen and unintelligent lizard has been 

 perhaps a little overrated. The group of birds, in fact, 

 is a group which is 'quite equivalent to that of reptiles on 

 the one hand and to mammals on the other ; but the 

 two first are rather nearer to each other than either are 

 to birds. In fact, the common starting point of both 

 birds and reptiles was, as far as we can see, something 

 in the nature of a very simply organized reptile. To 

 return, however, to our living birds, with which alone 

 we are concerned here. It will be noticed, particularly 

 well in the case of a long-legged bird such as a crane or 

 stork, that when a bird is standing upright it stands 

 upon its toes only. Above the toes, which are either 

 three or four in number, with a few exceptions, such as 

 the ostrich, is a long bone which is not, as might be 

 supposed, the equivalent of our shin bone. This long 

 bone is in reality the ankle bones, plus what are techni- 

 cally termed the metatarsals, i.e. those bones which in 

 ourselves lie between the ankle bones proper and the 

 phalanges or bones of the toes themselves. In the human 

 foot the phalanges are the separated toes, while the 

 metatarsals occupy the greater part of the foot. Birds, 

 therefore, have this region of the foot enormously 

 elongated. But the feature is not absolutely distinctive 

 of them, since even in mammals which walk upon their 

 toes, like the horse, the metatarsals are also long. There 

 are other instances of the same elongation of the middle 

 part of the foot. 



All birds, so far as is known, lay eggs, from which are 

 hatched in due course young birds that resemble their 



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