are here quite separate. This stage, then, carries us back towards 
the ancestral, reptilian, fore-limb used for walking, or perhaps 
for climbing. And there is another sign of this earlier, reptilian, 
period to be found in such a wing. At the tip of the thumb and 
first-finger, in unhatched ducks, game-birds, and water-hens, 
for example, you will find a small claw. By hatching-time 
the claw of the first finger will have disappeared, but it is still 
retained in the case of the duck and the water-hen. In the adults 
of all three you will rarely find more than the claw of the thumb : 
and this now serves no useful purpose whatever. 
Indeed, there seem to be only two tribes which have any use 
for wing-claws during nestling life. One of these is represented 
by the gallinules, that is to say, the coots, and water-hens, and 
their kind. You may test this whenever you have the good for- 
tune to capture a young water-hen. Place him outside the nest, 
and especially if it happens to be a little raised, you will see him 
make his way back, using feet, wing-claws, and beak. His 
wings, it will be noticed, at this stage are used as fore-legs. The 
other tribe is represented by that strange bird the hoatzin of | 
the Amazon. Here the two claws are really large, and they play 
a quite important part in his early life. 
For the young hoatzin is hatched in a nursery—a crude 
nest of sticks—placed on the boughs of a tree overhanging the 
water. As soon as hatched he begins to climb about the 
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