OF THE NERVUS OCTAVUS. 79 



nucleus, there are always found normal fibres between the dege- 

 nerated bundles, whether the cochlea may be removed or the nerve 

 sectioned. 



But in the latter case, the degeneration in the more dorsal and 

 proximal parts of the nucleus appears more intensive as the com- 

 parison of. f. i. fig. 2 on Plate II (cochlea-removal) with the fig. 

 8 on Plate IV or fig. 9 and tig. 10 on Plate V (octavus-sectioning) 

 may demonstrate. 



But as in its dorso-proxiuial border in both cases the normal 

 fibres reappear in the ventral nucleus , it may be stated , that the 

 rooth'bres chiefly enter at its disto-ventral pole , that the secundary 

 fibres chiefly leave it at its dorso-proximal border, but in this 

 manner that the entrance of root-fibres as well as the exit of secun- 

 dary fibres principally take place along the medial border of the 

 nucleus. 



In fact the dorsal root meets the medulla sqmewhat distally from 

 the nucleus, and the disto-ventral portion of it, is so intimately 

 Joined at the root , that it forms a part of the stratum latero-dorsale, 

 which here, lying close to the area ovalis of the C. R. surely 

 contains exclusively dorsal root-fibres. 



As soon as the fibres of the stratum latero-dorsale , in their cur- 

 vature round the area ovalis, have reached the dorsal border of 

 this area, they begin to diverge from it. They spread themselves 

 like a fan-radiation (see fig. \a Plate I) between the tuberculum 

 acusticum, the lateral portion of the dorsal nucleus of the eighth 

 nerve and the pars interim of the corpus restiforme. Even in distal 

 regions , but more easily distinguished in regions lying more proxi- 

 mally other fibres are running between the dorsal root-fibres in 

 the stratum latero-dorsale. 



We have already demonstrated that a little more proximally 

 the dorsal root-fibres of the ventral root aid to increase the stratum 

 latero-dorsale. Tliey remain intact after cochlea-removal, and dege- 

 nerate after section of the octavus (Plate VIII fig. 15 N. 8, Plate 

 IV fig. 8). The greater part of them hold themselves close to the 

 oval area, and curving round its dorsal border or penetrating through 

 it , they help to compose the systema intermedium nervi octavi. 



Being composed distally of dorsal root-fibres ,, proximally of ven- 

 tral rootfibres , this intermedia! system originates from the most 

 internal fibres of the stratum latero-dorsale , which may be considered 

 as the beinnnins of the systema dorsale nervi octavi. 



o O / 



But a few fibres of the ventral root, may increase the rest of 

 the dorsal root-fibres , which , having passed the ventral nucleus , 



