OF THE NERVUS OCTAVUS. 143 



of the inferior peduncle and the dorsal root, now still entering at 

 its ventral pole, embraces the nucleus with its degenerate fibres, 

 surrounding it ventrally and laterally, and giving it fibres, passing 

 queer through the nucleus. Most of these fibres gather at the dorsal 

 surface of the nucleus (fig. 26 A and B). 



But at these levels, the ventral (proximal) root has also entered 

 into the medulla oblongata. Its fibres - thick degenerated fibres 

 after the removal of the labyrinth - - perforate the inferior cerebellar 

 peduncle. Its most dorsally situated fibres here approach the dorsal 

 root-fibres and touch also the ventral border of the angular nucleus. 

 Ventral rootfibres therefore here enter in the ventral surroundings 

 of the nucleus angularis and continue to do so (Plate XXIII fig. 

 26 C and Plate XXIV fig. D) in more proximal levels, as the dorsal 

 rootfibres have disappeared. They provide the proximal ventral border 

 of it, until the nucleus joins the more lateral part of the nucleus 

 pedimculi inferioris cerebelli, from which the angular nucleus is not 

 distinctly separated. 



Now the angular nucleus and its surroundings being provided 

 in the manner here described, there remains at its distal end a 

 bundle of degenerated fibres, chiefly dorsal rootfibres, that lying 

 ii 11 mediately below the ependyma of the IV th ventricle, takes a 

 medial direction. 



On the other hand, the greater part of the ventral rootfibres, 

 which have passed queer through the pedunculus cerebellaris inferior 

 (fig. 26 C) and continue to do so in more proximal levels, also 

 take a straight medial direction. 



These ventral root-fibres have lost some fibres in the ventral 

 border of the angular nucleus , but on the other hand their number 

 is increased by dorsal rootfibres, originating from the ventral sur- 

 roundings of this nucleus. 



In this way there are found in distal regions two degenerated 

 bundles in the dorsal part of the oblongata. 



The one, the dorsal bundle, leaves the dorsal surroundings of the 

 angular nucleus, and directly below its ependym, it runs parallel to 

 the bottom of the IV th ventricle. In proximal levels it soon disappears. 



The other, a ventral bundle, chiefly composed of the continua- 

 ted ventral rootfibres, is much more important, as it may be traced 

 in all proximal levels. 



These two bundles (both composed of fibres of the two roots, 

 but the dorsal chiefly of dorsal root-fibres, the ventral chiefly of 

 ventral root-fibres) meet at the medullary surroundings of another 

 nucleus, situated in the lateral wall of the IV th ventricle and the 



