OF THE NE11VUS OCTAVUS. 133 



III. IN THE VENTRAL TRUNK. 



The dorsal rootfibres entering there have the same course as the 

 ventral rootfibres. Therefore for this part the schema of dorsal and 

 ventral-rootfibres are nearly equal. 



They participate to THE SYSTEMA VENTRALE NERVI OCTAVI. 



They follow several ways. 



1 . dorsal rootfibres to the contralateral nucleus trapezoides. 

 They are thick, superficial, transverse fibres, from which some 



remain in the same-sided nucleus. The rest, after passing the raphe 

 enter into the contralateral. 



2. dorsal root-fibres into the ventral system, to the nuclei ven- 

 trales tegmenti of the same side. They leave collaterals into their 

 lateral and ventral medullary layers and passing the raphe they are. 



3. dorsal root-fibres to the contra-lateral nuclei ventrales teg- 

 menti. They leave a few fibres in the medial hilus of the contra- 

 lateral nucl. olivare superior, and the rest, united to the fibres of 

 the intermediary system coming there, pursue their way in proximal 

 direction as 



4. dorsal root-fibres,' reaching through the ventral system the 

 contralateral fillet and the corp. quadrige minium porlicum. 



THE FIBRES OF THE VENTRAL ROOT 

 (Schema B). 



A considerable number of fibres of this root enters in 



I ITS DORSAL TRUNK. 



Directly or through the corp. restiforme the ventral rootfibres 

 participate to the formation of the stratum latero-dorsale, forming 

 chiefly its internal layer. They therefore also take part in THE SYSTEMA 



DORSALE NERVI OCTAVI. 



To the ventro-distal part of the ventral nucleus N. VIII they 

 give no fibres. They may give a few fibres to the ventral nucleus 

 in its dorsal and proximal part and to the tuberculum acusticum, 

 but they increase considerably the dorsal radiation upon the area 

 ovalis C. R. thus giving. 



1 . the ventral root-fibres to all cells of the nucleus dorsalis N. VIII. 



2. the ventral root-fibres reaching the descending root through the 

 area ovalis corporis restiformis. These perforating fibres participate to 



3. the ventral root-fibres in the intermediary system. Consequently 

 to its increase by ventral rootfibres, THE INTERMEDIARY SYSTEM OF 

 THE N. OCTAVUS is strengthened, and so are the ascending and 

 descending tracts. 



