xiii.] THE FROG. 189 



the ant-orbital process of the skull into the 

 nasal chamber and is finally distributed to the 

 nasal mucous membrane and to the integu- 

 ment of the nose. 



ii. The palatine is distributed : 



a. To the roof of the oral cavity. 



b. Its main trunk runs forward between the mucous 

 membrane of the roof of the mouth and the 

 skull, pierces the vomer and ends in the mucous 

 membrane of the anterior part of the palate. 



(This nerve is chiefly, if not wholly, derived from 

 the seventh nerve.) 



iii. The maxillo-mandibular divides into two trunks, 

 usually termed the second and third divisions of the 

 fifth nerve. 



a. Maxillary, passes outside the eye and is distri- 



buted to the integument of the upper jaw; an 

 anastomotic branch unites this nerve with the 

 palatine. 



b. Mandibular, passes between the temporal and 



pterygoid muscles, below the jugal, over the 

 articulation of the mandible and along the inner 

 face of the latter, to the symphysis, giving off 

 branches to the integument, muscles, teeth and 

 tongue. 



6. Abducent es 



arise from the floor of the hind-brain and leave the 

 ventral surface of the medulla oblongata close to the 

 middle line. Each then unites so closely with the 

 Gasserian ganglion and with the orbito-nasal division 



