190 ELEMENTARY BIOLOGY. [CHAP. 



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



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







7. The Faciaks 



take their origin from the floor of the hind-brain, 

 behind the fifth and in common with the eighth; 

 and, leaving the hind-brain, enter into close con- 

 nexion with the Gasserian ganglion. Each then 

 divides into two branches, an anterior and a pos- 

 terior. The anterior passes into the palatine division 

 of the fifth ; the posterior passes between the dorsal 

 and ventral crura of the suspensorium, enters the 

 tympanic cavity, runs over the columdla auris and 

 then, as it leaves the tympanum, receives a very 

 large branch from the glossopharyngeal. Finally it 

 divides into two branches, anterior and posterior. 



a. The former, which answers to the chorda tym- 

 pani of the higher Vertebrata, runs along the 

 inner face of the ramus of the mandible parallel 

 with the mandibular branch of the fifth. 



b. The posterior passes alongside the cornu of the 

 hyoid and supplies its muscles. 



8. The Audi for ii 



arise in common with the foregoing. Each divides 

 into two branches which enter the auditory capsule. 



The Post-auditory nerves are : 



9. The Glossopharyngei. 



These nerves arise, in common with the next, from 

 the medulla oblongata ; and the roots of both leave 

 the skull by an aperture behind the auditory capsule 

 on each side, and form a common ganglion. From 



