THE SKELETON 



59 



in the embryo except upon the theory which is part of the doctrine 

 of evolution that each individual epitomizes in his own develop- 



FIG. 31. 



Fio. 32. 



Fio. 31. The sternum seen on its ventral aspect. M, manubrium; C, body: 

 P, ensiform cartilage; Id, notch for the collar-bone; Ic 1-7, notches for the rib- 

 cartilages. 



FIG. 32. The ribs of the left side, with the dorsal and two lumbar vertebrae, 

 the rib-cartilages and the sternum. 



mental history the evolutionary history of the race to which he 

 belongs. 



The Ribs (Fig. 32) . There are twelve pairs of ribs, each being 



