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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