THE SKELETON. 9 



In birds, the posterior limbs alone assume the function of columns 

 P anterior limbs, formed for flight, constitute the 



Fig. 4. 



SKELETON OF THE COW, 



Fig. 5. 



SKELETON OF THE SHEEP. 



The number of ^bones entering into the composition of the skeleton of 

 Lomesticated animals, arrived at the adult period of life varies according 



