16 ELEMENTS OF COMPARATIVE ZOOLOGY. 



Remove the other bones from the cranium and notice 

 the various openings through which nerves and blood-ves- 

 sels find passage, and especially the large opening (fora- 

 men magnum) through which the spinal cord passes from 

 the brain to extend along the back. Can you find a place 

 especially fitted for the junction (articulation) of skull and 

 vertebral column ? 



On the sides of the hinder parts of the cranium are the 

 thin-walled ear-capsules. Cut into one and open the sac 

 (vestibule) of the ear containing a large ear-bone (otolith). 



