Muscles and Nerves 199 



When we carefiill}^ remove the upper part of a bird's 

 skull, we find that the brain occupies the whole interior, 



Fig. 145. — Comparison of skulls of Heron and Hawk, showing unlikeness caused 

 by difference in manner of procuring food. 



the shell or box of bone which protects it being very thin, 

 although strong. It would be very interesting if we could 

 compare the short and thick bullet-shaped skull and brain 



