NATURAL HISTORY OF SELBORNE. 
390 
are exceedingly sharp, so as to enable the bird to get a firm 
hold on the roughness of the bark. The hind-claw is very small. 
The two front claws are of unequal length, but the middle claw 
is so situated as almost to turn at right angles w^itli the leg, thus 
preventing any chance of the bird slipping. 
The tongue of the woodpecker, Fig. C, however, is the most re- 
markable piece of mechanism about his body. If the bill be opened, 
and the tongue drawn out, it will be observed that it can he pro- 
traded nearly four inclies from the gape of the beak. Tt is 
FlO. C — TONfiUF, OF AVOODPECKER. 
almost cylindrical, and can be pushed back into a sheath, 
which fits it, just as a pencil can be pushed back into a silver 
pencil-case. This is very similar to the mechanism that we 
find in the long worm-like tongue of the great ant-eater of 
