CoGHiLL, Cranial Nerves of Amblystoma. 227 



of the ear capsule. It contains all the motor VII fibers, com- 

 munis fibers from the geniculate ganglion and lateralis root 

 fibers. At the lateral border of the ear capsule it bears the 

 lateralis ganglion and divides into three large rami. 



The ramus inentalis {intl. VII.) contains all the lateralis fibers 

 of the hyomandibular trunk. It inclines a little caudad and then 

 turns ventro-cephalad along the suspensorium between the m. 

 masseter and m. depressor mandibulae nearly to the angle of 

 the jaw. As it emerges from between these muscles it divides 

 into two nerves of about equal size, the r. mentalis externus and 

 the r. mentalis internus. 



The r. vientalis externus {intl. ex.) gives off twigs to the sense 

 organs about the angle of the jaw, and posteriorly of this, and 

 passes cephalad laterally of Meckel's cartilage to the symphysis. 

 It innervates the lateral line organs which are arranged in an ir- 

 regular manner along its course. Its relation to the third cutan- 

 eous branch of the mandibular V has already been mentioned as 

 only that of contact. 



TJie r. mentalis internus {mtl. in.) passes ventrad from the 

 point of division of the main nerve, across the lateral side of the 

 m. depressor mandibulae at its insertion. It then turns inward 

 ventrally of the mandible and divides into two about equal 

 branches which diverge slightly and then pass parallel with each 

 other to near the symphysis. The distribution of the entire 

 nerve is to lateral line organs along its, course. 



Besides the two main branches of the r. mentalis, there are 

 small twigs given off between the m. masseter and the m. de- 

 pressor mandibulae. These pass directly out to sense organs 

 over the muscles. 



TJie r. jiigulaiis VII [jgl. VII) carries out all the motor 

 component of the hyomandibular trunk. It immediately inclines 

 caudad and meets the r. communicans IX + X ad VII, from 

 which it receives its general cutaneous component. The nerve 

 then enters the m. depressor mandibulae, innervating it by sev^- 

 eral large twigs, and emerges from its posterior border. From 

 this position the jugularis turns cephalad and inward subcutan- 

 eously, ventrally of the branchial musculature. It innervates 



