138 C. WINKLEll. THE CENTRAL COURSE 



a. the lateral bundle from the nucl. venlr. lemnisci 



/3. the medial bundle from the dorsal layer of the nucleus oliva- 

 ris superior 



The latter fibres are strengthened by fibres from the tractus 

 DEITERS ascendens. 



Those fibres reach the corpus quadrigerainum posticum and pro- 

 bably still go farther. 



This ascendent tract also is composed of rootfibres as well as of 

 sccundary fibres. But in this area of the lateral fillet there yet 

 remain an important number of fibres, probably belonging to the 

 octavus system, chiefly issued from the distal parts of the olivary 

 nuclei, which are known insufficiently. 



From the dorsal systema however a very important tract issues, 

 containing 



6. The secondary fibres in the ascendent tract of DEITERS. 

 They leave the nucleus of DEITEUS, in proximal direction, bend 



medially and form the lateral part of the fasc. long. post. They 

 end in the nucl. N. IV and III, whereas: 



7. The secundary fibres ascending in the fasc. longitiidinalis pos- 

 terior , reach these nuclei united with the ascendent DEITERS tract. 

 Nearly all the transverse fibres, issued from those two bundles to 

 provide the nuclei (not those , reaching the medial bundle in the 

 lateral fillet) are collateral fibres , and again their way is traced by 

 the root-fibres of the nervus octavus. 



THE DESCENDING FIBRES OF THE SECUNDARY 

 SYSTEMS OF THE NERVUS OCTAVUS. 



(Schema D). 



The fibres of the dorsal system , composed of rootfibres as well 

 as of fibres of the secundary system , also form descendent tracts. 



1. Fibres descending in the contralateral fasc. long, posterior. 

 They form a contralateral rather important tract, providing the 



nucleus VI, and the distal end of the nucleus N. XII. 



2. Fibres descending in the same-sided fasc. long, posterior. 

 Those fibres, slightly deviating ventrally in their distal course, 



unite with longitunal fibres, sent distally in the praedorsal tract, 

 from the decussatio of MONAKOW and of HELD. Together they go 

 towards the anterior column of the cord , where they are found 

 along the fissura anterior and the ventral margin of the medulla. 



