BONES OF LEG AND FOOT. 41 
lowest birds can scarcely walk; for perching on trees, etc., in the vast 
majority, most of which hop about there, and many of which climb or 
scramble in every imaginable way, with or without the aid of the tail; for 
swimming on the water, or diving, in a great many; for grasping and hold- 
ing detached objects in some, as the parrots, birds of prey, and a few 
others. The modifieations of the leg and foot are more numerous, more 
diverse, and more important, in their bearing upon taxonomy, than those 
of either bill, wing or tail. 
§ 72. (a.) THE BoNY FRAMEWORK. (Fig. 8, somewhat diagrammatic il- 
e lustration, taken from a loon’s right leg.) This ordinarily consists of twenty 
bones, of which fourteen are toe-bones, one is a little bone connecting the 
hind toe with the rest of the foot, one’a little bone in front of the knee- 
joint, and four are the principal bones from the hip-joint down to the roots 
of the toes. The first is the femur or thigh-bone, a, reaching from hip a, to 
knee B; a large terete bone, corresponding to the humerus of the wing. 
Then come two bones, 8, the ¢ébia, or principal (and inner) leg-bone, and c, 
the fibula, or lesser (and outer) leg-bone; both these joint with the femur 
above, and in front of this, the knee-joint, there is in many or most birds a 
AI 
ea 
P 
ee 
Fia. 8. Bones of leg and foot. 
little knee-pan, or knee-cap: the patella, p. The tibia runs to the heel, c, 
and there has an enlarged extremity to joint with the next bone: but the 
fibula is only a slender spicula not reaching the heel, but ending in a sharp 
point part way down the leg, and partly soldered with the tibia. It is only 
in a few of the lowest birds, that the tibia runs up to a point above the knee- 
joint, as shown in this figure: ordinarily, it ends at the knee itself. The 
portion of the leg represented by the femur, or from A to B, is the THIGH ; 
that represented by tibia and fibula is the Lea or crus; leg proper, there- 
fore, is from knee to heel, or B to c only. 
KEY TO N. A. BIRDS. 6 
'S 
