THE SKELETON 29 



and third bones are blended at their ends only, 

 the intervening shafts being separated by a 

 narrow, elongated interval. The representative 

 of the first metacarpal bone is small, and con- 

 sists of a short projection at the proximal end of 

 the composite bone. Of the three digits borne 

 by the three metacarpal bones, the first and 

 second have two phalanges, the third has one 

 phalanx only. 



The Skeleton of the Leg (Fig. 1) 



The most remarkable features of the pelvic 

 limb, or leg, are the firm and extensive fixation 

 of the hip-bone to the vertebral column, the 

 absence of a ventral union between the two 

 hip-bones, and the absence of an independent 

 tarsus. Like the wing, the leg may be divided 

 into segments as follows : — 



(1) Pelvic-girdle or hip- 

 bone 



Ilium. 



Ischium. 



Pubis. 



(2) Free part of the limb — 



(a) Thigh . . Femur. 



(b) Leg . . . Tibia and Fibula. 



view, the small cartilaginous rudiments which represent the first and 

 fifth metacarpal bones in the early chick embryo disappear during 

 the subsequent stages of development. 



