142 C. WINKLER. THE CENTRAL COURSE 



have been expected after lesions in the root-fibres of the nervus 

 octavus. Wherever a degeneration in the medulla oblongata is pro- 

 duced, nearly always black granules are found, for instance, in 

 the intermedullary rootfibres of all the nerves and especially in 

 those of the III th . The slightest degeneration in the oblongata 

 suffices to bring forward black globules nearly every- where. I believe 

 the reason of this fact, must be sought in the rapidity of the vital 

 functions in birds. I think, that in an early period after the opera- 

 tion the dislocation of the degenerated myelin-products begins and 

 that therefore the question whether there be a circumscript dege- 

 nerated area or not may be more difficult to resolve in birds. 



This observation however only relates to doubtful cases. Impor- 

 tant and circumscript degeneration in the entering roots and in 

 their initial paths after the removal of the labyrinth is found with 

 equal certitude in pigeons as in rabbits. 



1. The entrance of the rootfibres of the nervus octavus 

 in the medulla oblongata. 



Within a fortnight after removal of the labyrinth , in both roots 

 of the VIII th nerve many degenerate fibres are found. For in pigeons 

 as in rabbits the VIII th nerve enters into the medulla oblongata 

 with two distinct roots. The one is the dorsal , distal or lateral 

 root , the other the ventral , proximal or medial root. In both roots 

 however, besides the degenerate fibres, many non degenerate fibres 

 remain after the removal of the labyrinth. 



In frontal sections it is now easily demonstrated that the distal 

 root, lying laterally from the pedunculus cerebelli inferior, penetrates 

 into a nucleus, immediately after its entrance in the medulla 

 oblongata. 



This nucleus covers the entering root like a dorsal cap, and 

 according to the nomenclature adopted by EDINGER and WALLEN- 

 BERG, it may be called the nucleus angularis - - the ,,Eckkern" 

 of these authors. 



In this nucleus a large part of the degenerated dorsal rootfibres 

 enter, and as they spread through the nucleus, this nucleus itself 

 is intensely degenerated and found as a black spot after the removal 

 of the labyrinth (Plate XXIII fig. 26 A). 



In more distal regions, as long as the angular nucleus is resting 

 upon the dorsal end of the dorsal root it is found laterally from 

 the inferior cerebellar peduncle (fig. 26 A). In sections, falling more 

 proximally (fig. 26 B and C) the nucleus retires at the dorsal end 



