THE SKELETON. 



while the remaining fourteen support the face 

 round the mouth, the nose, and the eye-sockets. 



and 



73 



sur- 



Fio. 28. The ribs of the left side, with the dorsal and two lumbar vertebrae, the 

 rib-cartilages and the sternum: a, first and, 6, twelfth thoracic vertebra; c, first 

 lumbar vertebra. 



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 in the diagram Fig. 2) that partition be- 

 tween the dorsal and ventral cavities which in the trunk is 

 made up of the bodies of the vertebrae. In very early life it 



