1.52 C. WINKLER. THE CENTEAL COURSE 



Now in the first place, we must observe, that in pigeons --as 

 likewise in other birds there is not found any system, that may 

 be compared with the ventral octavus-system in rabbits. 



I cannot ascertain the existence of fibres forming a corpus trape- 

 zoides, neither can I find a nucleus olivaris superior, nor a nucleus 

 para-olivaris , nor a nucleus trapezoides as differentiated nuclei. 

 Moreover, there exists no trace of a ventral-trunk of the rootfibres 

 of the N. octavus. 



Therefore: pigeons have no sy sterna ventrale of the Nervus octavus. 



In accordance with this view, it might be supposed, that any- 

 thing like the ventral nucleus N. octavi, from which the greater 

 part of the corpus trapezoides originates, would not yet be diffe- 

 rentiated, or would be missing completely. This opinion is supported 

 by the situation of the angular nucleus, by its relation to the 

 dorsal root, by its place relative to the inagnocellular nucleus and 

 to the cortex cerebelli, all these being identical to the relations 

 of the tuberculum acusticum in rabbits. 



The dorsal root enters in it at its ventral border with the 

 greater number of its fibres, and continuates in a bundle found 

 dorso-laterally from it. The distal portion of the ventral root also 

 gives fibres to it. But the ventral root, perforating the fibres of 

 the pedunculus cerebelli far dorsalward from the spinal root of 

 the V tlie nerve, may not be compared with the complete ventral 

 root in rabbits. In rabbits the dorsal fibres of this root perforate 

 the area ovalis of the corp. restiforme far dorsalward from the 

 V th nerve. At least in distal regions. And here again is an argu- 

 ment defending the view , that for the distal and ventral portions 

 of the octavus-roots are much reduced in pigeons. 



This however is no impediment for the existing rootfibres to 

 take a course completely comparable, with that followed in rabbits. 



In pigeons the rootfibres found in the ventral bundle , divide , 

 into three parts: a descending rootfibres, b ascending rootfibres and c 

 transverse fibres going straight to the nucleus parvocellularis (the 

 ventral bundle sensu strictiori). The same is found in rabbits. Many 

 of the descending as well as of the ascending rootfibres remain among 

 the cells situated in the medio-ventral and central area of the portio 

 interna pedunculi cerebelli. 



These fibres are completely comparable with the descending root- 

 fibres remaining among the cells of the nucleus griseus rami des- 

 cendentis , or with the ascending rootfibres remaining among the 

 cells of the aequivalent nucleus BECHTEREW found in rabbits. 



Other descending fibres situated more medially in the portio 



