INTRODUCTION. 5 
THE LEG AND FOOT. 
A bird’s leg may be briefly described as having only the knee downward exposed ; 
the true thigh is concealed, but may be felt under the skin on the side of the body, 
The true knee is close to the body just under the skin. ‘The first exposed joint which is 
apparently the knee, but which bends back- 
ward, is really the heel. (See illustration.) 
The bird does not walk on the foot (from 
the heel downward), but merely walks on 
his toes. 
Booted Tarsus Scutellate Tarsus 
The Tarsus, which is measured from the bend of the leg (end of tibia) to the roots 
of the toes (C to D in illustration), is an important factor in the identification of 
many species. The feet are very variable in shape and arrangement of the toes. 
These variations are of the greatest importance, representing generic and, often, 
family differences. 
Types of Feet. — Water Birds. 
