2 8o COMPARATIVE ZOOLOGY OF CHORDATES 



abducens nerves in a fenestra prootica. In front of the pila 

 antotica the optic, oculomotor, and trochlear nerves, and the 

 pituitary vein pass. 



The olfactory or nasal capsules are formed at the front of 

 the skull. They are separated from one another by the inter- 

 nasal septum formed from the trabecular which anteriorly 



