OUR FACE FROM FISH TO MAN 



powerful body muscles that drive the body through 

 the water. 



The braincase is the thrust-block (Fig. 10) that 

 receives the forward push from the backbone and 



Fig. 10. The Wedge-shaped Braincase of a Fish, Acting as a 

 Thrust-block or Fulcrum for the Backbone. 



For details, see p. xiv. 



the reaction from the water. The roofing bones 

 over the braincase and the keel bone (parasphenoid) 

 on the under side of the braincase together form 

 a long wedge which is thrust forward into the 



water. To the sides of the skull are attached first, 



22 



