OF THE NERVUS OCTAVUS. 95 



4 e dorsal rootfibres (from the two roots) passing through the 

 portio interim towards the descending root. 



5 e dorsal roottibres (from the two roots) forming the interme- 

 dia.! system. 



Now, as soon as the corpus restiformis, deviates into the cere- 

 bellum the aspect of those fibres changes. The two slings of root- 

 fibres, between which the area ovalis was enclosed, mix together, 

 or rather the root-fibres penetrating through the oval area, found 

 in the proximal sections (Plate VIII fig. 15 N. 8 and N. ( J), are 

 the preliminaries of the union of the dorsal and medial sling of 

 root-fibres. And as the area leaves the medulla to become cerebel- 

 lar inferior peduncle, (Plate IV fig. 8) the combined root-fibres go 

 farther. They now have a somewhat proximal direction and may 

 be called ascendent root. But they are originating from the two 

 roots. The greater part may be medial fibres of the ventral root. 

 The proximal dorsal fibres however participate to it and a smaller 

 part of them may belong to the dorsal root. 



As I have demonstrated , the nucleus of DEITERS has now disap- 

 peared, but the surroundings of these fibres have remained unchanged. 

 They are surrounded by cells of the same shape and of medial 

 size, like those which in more disal sections characterized the 

 nucleus griseus round the descending root. But here the nucleus 

 griseus of this ascending root is called nucleus of BECHTEREW. 



It is not difficult (Plate IV fig. 8, Plate V fig. 10) to demon- 

 strate the relations of the ascendent fibres to this nucleus. Many 

 of them remain there, but a few exceed this nucleus towards the 

 nuclei mediales tecti, from which the nucleus of BECHTEREW is less 

 sharply marked off, as from the dorsal nucleus. 



In this way the greater part of the root-fibres of the nervus 

 octavus entering in the medial trunk between area ovalis and spinal 

 V th root, join a smaller part that has sought a dorsal way in order to 

 reach the medio-ventral quadrant of the portio interim, forming a 

 long tract, an ascending and a descending root of the nervus octavus. 



This tract is surrounded by a long stretched nucleus. 



In proximal sections it is called the nucleus of BECHTEREW, more 

 distally the nucleus griseus of the descending root, still more distally 

 it confluates with the proper nucleus of the corpus restiforme, 

 and dorso-medially from this nucleus the dorsal nucleus of the 

 nervus octavus appears, extending in a similar way. In this way, 

 views closely allied to the elder views of ROLLER reappear. 



Perpendicular collaterals part from this long tract during the 

 whole of its course. They perforate the nucleus griseus and the 



