Kappers, Teleostean and Selachian Brain. ' 99 



region which is the continuation of that region of the spinal cord 

 which is situated next to the central canal. 



As for the secondary relations of the static region, I must men- 

 tion first the strongly developed fchrce arciiatcB internee and externce, 

 which as in the ganoids, pass through the raphe as diffuse fibers 

 and not as in the teleosts as compact bundles which spread out 

 laterally. As before observed, the lower arcuate fibers, the real 

 fibrae externae, are formed chiefly by decussating cerebello-spinal 

 fibers, while the innermost might represent bilateral connections. 

 In correlation with the strong development of this region their 

 number is very considerable. Whether the fibers which are more 

 dorsally situated are to be considered as decussating parts of the 

 fasciculus lateralis, as I observed when discussing this bundle, 

 cannot be made out. On the other hand, another secondary 

 connection of this region has long been known, the fasciculi 

 mediani, first described by Stieda and after him by Rohon and 

 Haller. Rohon considered them as a separated part of the 

 dorsal longitudinal bundle and thought he saw them still in the 

 trigeminus region. Sanders mentions them but does not say 

 anything further about them. Haller, with whose opinion I 

 quite agree, records that they begin in the region of the acustico- 

 facialis, from which they bend inward medially of the motor 

 facialis root then run backward under the ventricle between the 

 sensory region of the ninth and tenth laterally and the motor 

 region of these nerves mesially (Figs, cv and cvi) and finally enter 

 the spinal cord (Fig. cvii), where they are situated close to the 

 central canal (Fig. cviii) and from time to time some of their 

 fibers pass into the ventral column of motor cells. The size and 

 medullation of their fibers are the same as in the fasc. long, 

 posterior and I am of the opinion that we have here a caudal 

 relation between the octavus center and the motor regions of the 

 spinal cord corresponding to Mauthner's fibers in the dorsal 

 longitudinal bundle itself in the bony fishes. 



The nervus glossopharyngeus is just like the anterior root of the 

 vagus. The motor fibers of this nerve enter with the sensory and 

 terminate partly decussated and partly uncrossed in the group of 

 cells situated under the ventricle laterally of the fasc. long, 

 posterior. But before these fibers enter their nucleus they take 

 a longitudinal course in a separate bundle laterally of the chief 

 part of the fascicle, as has been figured for the vagus in Fig. cv. 



