2i6 Journal of Comparative Neurology. 



little posteriorly of the Gasserian ganglion and is separated 

 from it by the cartilaginous base of the ear capsule. The 

 ganglion of the posterior division of the lateralis VII root lies 

 still farther laterad on the hyo mandibular trunk near and 

 beyond the lateral border of the ear capsule. The ganglia of 

 the auditory roots lie at the entrance of the nerve into the ear 

 capsule and project some distance into the capsule. The 

 ganglion of the dorsal VIII root is closely compressed against 

 the posterior face of the ganglion of the ventral VIII root. 



2. — TJie Root of the Trigemimis. 



The fibers of the motor V component appear in the ventro- 

 lateral margin of the cinerea, some distance caudad of the exit. 

 From this position they turn latero-ventrad and emerge from 

 the postero-ventral portion of the area of exit of the entire 

 nerve. They at first occupy a ventrolateral position in the 

 root, but as they approach the ganglion they come to lie dorsally 

 of that part of the root which belongs to the r. ophthalmicus 

 profundus. Within the ganglion the motor component inclines 

 laterad and issues from the ganglion as the postero-ventral por- 

 tion of the r. mandibularis. 



The general cutaneous portion of the trigeminus forms into 

 two div^isions some time before it reaches the ganglion. One 

 of these divisions lies dorsally of the motor component and the 

 other ventrally of it. However, these two divisions are closely 

 compressed together about the motor component, and the line 

 of division between them is not always perceptible. In one 

 series of sections, in which the motor nerves are elsewhere well 

 differentiated, there appear a few medullated fibers which seem 

 to pass directly through the ganglion and enter the r. ophthal- 

 micus profundus. The significance of these fibers has been dis- 

 cussed in connection with the innervation of the m. levator 

 bulbi. The dorsal division of the ganglion, the Gasserian 

 ganglion proper, gives rise to two nerves : from its lateral por- 

 tion, the general cutaneous component of the mandibular trunk; 

 from its mesial portion, the general cutaneous portion of the 

 infraorbital trunk. The latter component is generally known as 



