168 THE STORY OF THE BIRDS. 
of them, and in the various interlacings, fusions, split- 
tings and crossings that they exhibit in various groups. 
In the feet of the five-toed lizards one great flat strap, 
with a little splitting up in the most regular order, 
bent their toes all by a common pull, but in the birds 
there began with the separate use of the opposable 
first toe a series of changes and separations, reunit- 
ings and resplitting of strands, till in the true perch- 
ers the hind toe appropriates to itself the sole use of 
a distinct tendon. When some swifts put all their 
toes front, Nature gave them again something similar 
to the flat strap of the reptiles, even upon the very 
border of the Passeres. 
Thus we can see how there lies yet largely unread 
in the arrangement, the webbing, the jointing, and es- 
pecially in the arrangements for one a large chap- 
ter of the story of the birds. 
