XIII.] THE FROG. 181 



chamber and is finally distributed to tbe nasal 

 mucous membrane and iio the integument of the 

 nosOi 



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 mem- 

 brane of the anterior part of the palate. 



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

 seventh nerve.) 



iii. The maxillo-mandihuldr 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. 



h. 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. Abducentes 



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 

 of the fifth as to appear to be only a subdivision of 

 the latter (see 5. i. a and b). 



