THE SKULL. 



73 



the face and surround the mouth, the nose, and the eye- 

 sockets. 



Fio. 25. The ribs of the left side, with the dorsal and two lumbar vertebrae, 

 the rib cartilages and the sternum. 



Cranium. The cranium is a box with a thick floor and 

 thinner walls and roof. Its floor or base represents in the 

 head (as is depicted diagrammatically in Fig. 2) that par- 



