OF THE NERVUS OCTAYUS. 91 



group of the dorsal nucleus is forming the lateral border of its 

 principal and lateral cells. Here the nucleus griseus radicis descen- 

 dentis is not yet gone, and is joined to the ventral group. A little 

 more proxiinally the corpus restiforme (or its oval area) retires into 

 the cerebellum., and nearly at the same moment the nucleus of 

 DEITERS disappears. But the nucleus griseus of the ventral root-fibres 

 together with the. ventral group of the dorsal nucleus have remained, 

 and are situated still laterally of the latero-dorsal cells of the dorsal 

 nucleus. And on that plan cells of different, mostly of medial 

 size, are forming a larger area (Plate IV fig. 8), which has been 

 called since long the nucleus of BECHTEIIEVV. It might have been 

 called also the nucleus griseus of the ascending root. 



It seems to me , that there exists some difficulty to define the 

 nucleus of BECHTEREW. I only wish to state , that this nucleus 

 certainly may not be identified with the proximal portion of the 

 lateral groop of cells in the dorsal nucleus, as is done by some 

 authors, f. i. LEWANSUOWSKI. 



The relations of the ventral rootfibres to the nucleus griseus radicis 

 descendentis and to the cells of the ventral apex of the dorsal 

 auditory nucleus, during the whole course of the descending root 

 are clear enough. They become still more transparent, as the nucleus 

 of DEITERS has disappeared and the ventral rootfibres instead of 

 forming a descending radix have a somewhat proximal direction 

 (the ascending root), but the relation of the root-fibres to this nucleus, 

 with its cells of midling size between small ones, has not altered. 

 Only its name is here no longer ,,a nucleus of the ascending ven- 

 tral rootfibres". This is the nucleus of BECHTEREW, lying between 

 the corpus restiforme, as it retires towards the cerebellum , and the 

 latero-dorsal cells of the dorsal nucleus, or between the nuclei 

 tecti cerebelli and the motor nucleus of the nerve V in the lateral 

 wall of the ventricle, characterized by cells of midling size scattered 

 between small cells (Plate IV fig. S and Plate V fig. 9). 



Now still remains the nucleus of the VI th nerve, as the last of 

 the cell-groups entering into the surroundings of the nucleus dor- 

 sal is nervi octavi. (Plate VII fig. 7 A H). The cells of this nucleus, 

 scattered round the genii of the VII th nerve, bordered, but not 

 sharply, by the cells of the principal and the medial group of the 

 dorsal nucleus, are found latero-dorsally from the genu N. VII in 

 distal sections, latero-medially from it in proximal sections. In this 

 way, they force the leaving root-fibres of the VI lh nerve, to evade 

 the genu, before taking their straight dorso-ventral direction. 



The cells of this nucleus also receive rootfibres from the nervusoctavus. 



