VI FORM AND FUNCTION 165 
various intermediate stages before we arrive at separate- 
toed feet. In the Dabchick and the other Grebes, the 
toes are not connected, but there is on either side of 
each a broad expansion of skin. In the Kingfisher 
the second, third, and fourth toes are fastened together 
Pasir a that ens « 
a 
Fic. 43. 
Foot of (1), Woodpecker ; (2), Grebe. 
for most of their extent. The Woodpeckers, Cuckoos, 
and Toucans have a most curious form of foot called 
zygodactyle or yoke-toed, the first and fourth toes 
pointing backward, the other two forward—a foot 
specially adapted for climbing. In the Swift all the 
