1 06 ELEMENTARY BIOLOGY. [CHAP. 



y. The Ophthalmic or orbtto-nasal ; its distribu- 

 tion may now be studied by turning the animal 

 over and examining from the dorsal aspect. 

 Remove the nasal and sphenethmoid bones 

 to its level; and note its branches to the 

 antero-dorsal integument of the head. 



e. The "jth or facial ; intimately connected with 

 the Gasserian ganglion and the trigeminal. Ex- 

 amine it, from the ventral aspect, on that side 

 at which the eye remains. 



a. Its root ; arising, side by side with that of the 

 5th, from the side wall of the medulla ; the 

 two entering the Gasserian ganglion. 



y8. Its anterior branch {palatine nerve) ; leaving 

 the Gasserian gangUon immediately external 

 to the ophthalmic branch of the 5 th, and 

 passing forwards, perforating the vomer, to be 

 distributed to the mucous membrane of the 

 roof of the mouth. 



y. The maxillo-palatine commissure ; connecting 

 the palatine and maxillary nerves; on a level 

 with tlie front end of the eye-ball. 



8. The posterior branch of the 7 th; leaving the 

 outer side of the Gasserian ganglion, im- 

 mediately behind the maxillo-mandibular 

 nerve, and passing outwards and backwards 

 dorsal to the columella auris (beneath it as 

 here seen). Its distribution may best be 

 studied later. 



f. The <.}th and 10th (post-atiditory nen'cs) -, arising 

 close together from the medulla posteriorly to 



