168 C. WINKLER. THE CENTRAL COURSE 



a rest of the existing contacts with the octavo-motor systems. The 

 static periferical organ having the appropiate nerve-endings to be 

 stimulated by mechanical blows brings a part of them the 



sound-waves to perception, and a farther developement of this 

 perception was of great psychological importance. 



Most of these however - sound-waves as well as all changes 

 in endolymph or in otoliths - produce sensu-motor impulses , to 

 wich only a vague perception is associated. From these no farther 

 psychical developement took place , but they gave rise to an auto- 

 matic motor function of high developement and of an enormous 

 importance for the animal. 



In this way I am viewing the functions of the labyrinth related 

 to the central distribution of the N. octavus. 



Now , as we have seen in the second chapter , in rabbits the 

 octavo-motor systems were chiefly homo-lateral, and their slight 

 contra-lateral representation was neglected. The sensory octavus- 

 systems , neglecting their less numerous homo-lateral representation, 

 were chiefly crossed systems. 



The neglection of the homolateral or crossed systems however 

 is no longer permitted in regard to the octavus-systems in pigeons. 

 Their anatomical peculiarities, told in the third chapter were as 

 follows. 



Firstly , the dorsal root was unimportant , perhaps in account 

 with the incomplete developed cochlea - - the lagoena. 



Secondly, and perhaps consequent to this, the tuberculum acus- 

 ticum and the ventral octavus-nucleus were not yet differentiated. 

 They were, represented in pigeons by a relative important nucleus, 

 the nucleus angularis, where as the ventral and the intermediary 

 octavus-systems were totally or nearly totally absent. 



Thirdly , the ventral root having an important radiation in the 

 oblongata, together with the dorsal root, provides with direct root- 

 fibres the octavus-nuclei the so-called nuclei parvocellulares - 

 of both sides. From these nuclei representing the dorsal octavus- 

 nuclei an important systema dorsale nervi octavi issues, more con- 

 siderable than in rabbits. Through this dorsal system direct rootfibres 

 from one side reach as well the nucleus parvocellularis as the 

 corpus juxtarestiforme at the other side. 



Fourthly, the nucleus magnocellularis, representing DEITEKS nucleus, 

 and the ,,Acusticusfeld" representing the area of the radix descendens 

 and ascendens, with its grey masses (BECHTEREW'S nucleus), are 

 without doubt similar organs , from which octavo-motor systems issue, 

 as they are in rabbits. 



