Kingsbury, Brain of Nectiiriis. 147 



enter the Gasserian ganglion which is situated extra-cranial- 

 ly. From this ganghon arise the usual three branches, 

 exclusive of several small twigs composed of fibers from the 

 branch of the "dorsal" seventh which is associated with the 

 Gasserian ganglion. 



VI. The abducens is quite small, being in fact the least of 

 the cranial nerves. It arises a short distance caudad of the 

 seventh, from the ventral aspect of the metencephal. It passes 

 laterad to the seventh, with which it is associated for a short 

 distance, though always distinct from it. It soon leaves it, 

 "however, to pass cephalad to the Gasserian'ganglion, immed- 

 iately ventrad of which it lies. 



Dorsal VII. By this name, employed by Strong ('95 ), will 

 be designated a nerve which until^recently has been little under- 

 stood. It leaves the oblongata at about the level of the exit of 

 the facial proper, and immediately divides, one branch joining 

 the trunk of the seventh and eighth nerves, the other passing 

 cephalad to the Gasserian ganglion, with which its ganglion is 

 fused, lying just dorsad of it. This nerve becomes ganglionated 

 slightly before the fifth, however. A very small bundle of 

 fibers leaves it just centrad of the ganglion to join the 7th nerve 

 just before it enters the ear capsule. From its ganglion two 

 or three small roots pass immediately dorsad ; a large part of 

 the fibers pass cephalad in company with the ophthalmic branch 

 of the fifth, the ramus ophthalmicus superficialis VII, Strong. 

 By Von Plessen ('91 ) and C. J. Herrick ('94) this branch to 

 the Gasserian ganglion has been considered as belonging to the 

 trigeminus, clearly, however, without recognition of the ulti- 

 mate distribution of its fibers to the sense-organs of the lateral 

 line system, as worked out by Strong. The reference of this 

 nerve to the seventh is based merely on the fact of its exit from 

 the brain being very close to that of the seventh proper. It 

 belongs however to a system peculiar to the IcJitJiyopsida, and 

 until more is known of its origin, and of the'segmental value of 

 the other cranial nerves, a reference of this nerve to the seventh 

 must be merely a matter of convenience. The other division of 

 the dorsal seventh will be spoken of with the following nerves. 



