A BIRD’S FORE LEG. 14 
penguins, is entirely free. The other two fingers are 
not only inclosed in the same skin and other tissues, 
but their bones at the base are fused together in such 
a way as to form a strong wing tip. In very young 
birds they are free. Birds, bats, and the fossil-flying 
lizards all fly (or flew) largely by their fingers, and the 
last almost solely by the little finger. 
The claws on the fingers of the Archwopteryx were 
perhaps useful, as we have seen, in climbing. 
Many more birds than we usually suspect show 
vestiges yet of claws on the fingers. Our turkey vul- 
ture, some ostrich forms, some swans and _ others, 
even up as high as the thrush forms, have claws vari- 
ously located on the wing tips of the adult. Some 
young gallinules have these claws so functional that 
they can pull themselves about over reeds and grass 
with them, and in an allied bird in South America, 

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Wing of young hoactzin, showing claws. 



the hoactzin, the young, while yet unfledged, can climb 
in a crawling attitude over bushes and among the 
branches of trees. In this latter case the claws are 
shed when the nestling is fully feathered. 
Besides having the front paw thus fused and mit- 
tened, the modern bird’s fore leg is otherwise much 
