cxvi Journal of Comparative Neurology. 



filled with black lumps, while of the more ventral fibres passing 

 toward the median line, only occasionally one was found degenerate 

 and that too only near the point of separation of the two divisions of 

 the vagus. 



The fibres passing from the raphe to the vagus were demonstra- 

 ted with equal certainty. In the experiments above mentioned these 

 fibres were unaltered, but were strongly affected in a dove whose 

 vagus and glossopharyngeus together with their ganglia had been re- 

 moved. From this we conclude that these fibres arise from the cells 

 of the ganglion and, after crossing in the raphe, pass to the higher 

 centres via the ventral bundles of the opposite side. 



That vagus fibres originate from the ventral nidulus is much more 

 difficult to prove, from the fact that the cells are scattered, that the 

 fibres passing to the raphe pass between them, and that cells of this 

 nidulus undoubtedly send fibres into the hypoglossus. But the experi- 

 ments on doves mentioned above seem to show that this is the case. 

 When the vagus had been destroyed, the ventral nidulus of that side 

 was plainly smaller than the other, the outer cells being wanting, 

 while the inner ones which are related to the hypoglossus remain. 



These points and the relation of this common vagus-hypoglos- 

 sus nidulus to the nidulus of the accessorius, lead to the view that in 

 birds the latter has a single continuation cephalad, the common vagus- 

 hypoglossus, while in mammals it has two such continuations, the 

 "nucleus ambiguus" and the major nidulus of the hypoglo«;sus. 



(c) Glossopharyngeus. In the dorsal commissure of the cervical 

 cord are numerous fibres directed mesad and strongly cephalad which 

 are larger than the others. Passing caudad, they arch under the dorsal 

 columns and disappear in the dorsal cornu ; a smaller bundle of 

 fibres, however, passes ventrad and disappears in the lateral columns. 

 Passing cephalad, after crossing in the commissure, they follow the 

 ventral surface of the diverging dorsal columns, corresponding to the 

 funiculi solitarii of mammals. Diverging as the fourth ventricle widens 

 this fibre-complex gradually separates on each side into a dorsal and a 

 ventral part. From the latter rather numerous nerve fibres pass ven- 

 trad, cross over the vagus tract, and disappeared in the formato reti- 

 cularis. The other fibres of the ventral part, now constituting the 

 glossopharyngeal root, take up a direction parallel to the emerging 

 vagus root and thus pass to their point of exit. After the ventral 

 part of the solitarius is almost spent, the fibers of the dorsal part turn 

 ventrad and appear to join the glossopharyngeal root, except those 

 lying farthest dorsad which continue in the original direction. 



