OF THE NERVUS OCTAVUS. 7 1 



As soon as the dorsal rootfibres and their continuation in the 

 latero-dorsal layer are degenerated, a certain number of these fibres, 

 lying upon the lateral border of the oval area of the restiforni 

 body , circle round it , first running dorsally , then turning round 

 its dorsal border, and returning in ventral direction through the 

 pars interim C. 11. From here they perforate the grey matter of 

 the spinal V th root and reach the dorsal border of the oliva, and 

 taking a medial direction , participate with the transverse fibres in 

 the stratum d. (Plate I fig. 10, Plate 11 fig. 2). 



But only a few fibres in this intermedial system are brought to 

 degeneration after the removal of the cochlea. 



Much greater is the number of fibres degenerating in this system 

 after root-section. 1 have already mentioned, how in that case, the 

 number of degenerated fibres limiting the lateral border of the 

 area has increased. Also I have shown , that many of them are 

 seeking a shorter way to its medial border. They perforate the 

 oval area instead of making a curve around its dorsal border. 



Apparently those fibres - - as described, they are the fibres pas- 

 sing from the ventral root in the stratum latero-dorsale - - being 

 themselves intermediary fibres between the roots, help in a consi- 

 derable manner to augment the intermediary bundle to the stratum d. 

 (Plate VIII fig. 15 N. 511, especially fig. 15 N. 9 und 11). 

 After all , this intermedial system contains fibres of both auditory 

 roots, and may be defined in the following way. 



The root-fibres having entered the central system in dorsal direc- 

 tion , pass in the latero-dorsal layer, pass round or through the 

 oval area of the corpus restiforine to gain the ventral direction in 

 its pars interna. Penetrating there and through the spinal root of 

 the V Lh nerve , they reach the dorsal border of the facial nucleus 

 and of the medullary surroundings of oliva superior and accessory 

 nucleus on the same side. In these nuclei they send fibres, but 

 the greater part now take a ventral direction and become the trans 

 verse fibres of the stratum d in the systema ventrale. 



This stratum d therefore will afterwards be reckoned to the 

 systema intermedium nervi octavi , a view , seeming perhaps arbi- 

 trary, as some of its fibres take their origin in the ventral system. 

 But a severe separation is impossible here. For as we will soon 

 demonstrate the intermedial system gives also fibres to the super- 

 ficial (ventral) layers of the corpus trapezoides. 



It has advantages to reckon all the dorsal root-fibres , the so-called 

 fibres of HELD, to the intermedial system. But this system not 

 only contains root-fibres. There is also a secundary system and even 



