148 C. WINKLER. THE CENTRAL COURSE 



of the surroundings of the parvo-cellular nucleus. Now from the 

 ventral bundle an important number of fibres, takes a direct medial 

 course in order to reach the raphe. Degenerate fibres leaving the 

 (degenerate) surroundings of the parvo-cellular nucleus, and passing 

 through the bundle leaving the hilus of this nucleus, join the 

 degenerate transverse fibres, which also reach this bundle. All these 

 fibres reach the raphe at the place where the fasciculus longitudi- 

 nalis posterior is found, cross it, and continue their course in the 

 same contra-lateral bundle towards the hilus of the contra-lateral 

 nucleus parvo-cellularis. Together they form thy very important systema 

 dorsale nervi octavi wherein many rootfibres , degenerating after the 

 removal of the labyrinth , are found. 



l ly . An important number of degenerate fibres enter into the 

 contralateral dorsal system , and may be traced into the hilus of 

 the contra-lateral parvo-cellular nucleus. In distal regions there are 

 not yet found many degenerate fibres, but their number increases 

 rapidly in proximal sections (fig. 26 D, E). Here the contrast be- 

 tween the degenerated homo-lateral and contra-lateral nucleus is 

 marked. The lateral surroundings of the homo-lateral nucleus are 

 intensely degenerated , the hilus is so in a relative slight degree. 

 The hilus of the contralateral nucleus is intensely degenerated, 

 its surroundings are so only slightly (fig. 26 D E). 



It is not only in this nucleus that degeneration is found. Here 

 however it is intense. From thence a few degenerate fibres spread 

 into the proximal part of the ,,Acusticusfeld" and though their 

 number is small, they there take the same ascending and descen- 

 ding course as at the homolateral side. 



In this way rootfibres not only reach the homo-lateral parvo- 

 cellular nuclei , but a very important number of them , passing 

 through the dorsal systema reach this coutralateral nucleus (fig. 26 

 D, E and fig. 27). 



2 ly . The here described path however is not the only one follo- 

 wed by the rootfibres in the systema dorsale. During their course 

 towards the raphe many fibres leave the principal bundle. Fibres 

 enter into the formatio reticularis. There they first go ventrally, 

 gather dorsally from the facial nucleus and bend distally. But there 

 these fibres soon disappear. At the distal end of the oblongata they can- 

 not be distinguished with certainty among the small black granules, 

 which are found here spread over the whole section and such is 

 likewise the case in the spinal cord. It is impossible in pigeons 

 to draw a conclusion concerning the existence of dispersed degene- 

 rated fibres. 



