OF THE NEEYUS OCTAYUS. 153 



interim , send transverse fibres to the VI th nucleus , and going more 

 distally even into the X th nucleus. More proximally those transverse 

 fibres either originate from the ventral bundle or from the ascen- 

 ding fibres and may be traced to the nucleus parvocellularis. To 

 this nucleus also a portion of the dorsal rootfibres (the dorsal bundle) 

 may be traced. 



All these fibres follow the same course , which has been described 

 in rabbits , and it is evident , that the parvocellular nucleus in 

 pigeons has the same relation to these rootfibres, as in rabbits the 

 nucleus dorsalis N. VIII has. 



In this nucleus the dorsal and ventral bundle meet in a similar 

 way as the systema latero-dorsale and the medial-roottrunk in rab- 

 bits are doing in the dorsal nucleus. Only in pigeons its distal end 

 is reduced, but its proximal end again is provided for by transverse 

 fibres of the ascending root, as in rabbits the proximal end of the 

 dorsal nucleus is. 



And if in pigeons the nucleus parvo-cellularis really represent 

 the dorsal octavus nucleus, if the angular nucleus represent the 

 tuberculum acusticum with the not yet differentiated ventral octa- 

 vus-nucleus, if the cells in the medio-ventral and central area of 

 the portio interim may be homologised with those in the nucleus 

 griseus rami descendentis (in distal regions) or with those in the 

 nucleus BECHTEREW (in proximal regions) , then only one nucleus , 

 the nucleus magnocellularis, remains to be homologized with the 

 nucleus of DEITERS. 



This magnocellular nucleus is situated in the dorsal edge of the 

 portio interna, between the angular and parvo-cellular nuclei, it 

 contains very large cells and after removal of the labyrinth , dege- 

 nerate rootfibres, though distributed every where in the neighbour- 

 hood , may pass through it , but do not remain in it , as they do 

 in the nuclei parvocellulares or angularis. Therefore its position , 

 its structure , its relation to the rootfibres are all pleading in favour 

 of the meaning, that this nucleus may represent, what in rabbits 

 is called the nucleus of DEITERS. 



Until now, there has been no great difficulty in comparing the 

 roots and nuclei of the pigeon and the rabbit. 



Pigeons have no ventral system , consequently no intermedial 

 system is found , but a dorsal system they have. 



In pigeons the ventral and distal portion are reduced , but the 

 dorsal systema is considerably developed and is built in a similar 

 manner as in rabbits. 



Yet a very remarkable difference does exist. 



