OF THE NEKVUS OCTAVUS. 137 



and BECHTEREW) and from the olivary bodies issue secundary 

 systems. Those systems (without those of the nuclei olivares supe- 

 riores, nuclei paraolivares and nuclei trapezoides have been schematised). 

 They augment all the systems of rootfibres, and participate to 

 the systema ventrale and interniedium, following the way traced 

 by the root-fibres. 



1 . The secundary fibres in the systema ventrale are chiefly issuing 

 from the ventral nucleus and are situated among all its layers. 

 To this secundary system certainly is added an important one from 

 the nuclei olivares especially in the stratum c of this system, pro- 

 bably following afterwards paths as the first. 



2. The secundary fibres in the systema intermedium are also 

 issuing from the ventral nucleus, but some of them may issue 

 from the nucleus of DEITERS. To these secundary fibres the olivary 

 bodies again add many fibres, not yet medullated at birth. 



Those two systernata give now its origin to an ascendent, chiefly 

 same-sided (but also contralateral) tract, which together with spinal 

 fibres and octavus-rootfibres takes the way of the ,,vental ascending 

 spino-cerebellar tract". Going proximally in the ,,aberrirendes Sei- 

 tenstrangbundei" these primary and secundary octavus-fibres, they 

 reach with the lateral fillet the outer layer of the pedunculus superior 

 cerebelli, cross its bracchium conjunctivum and reach the nuclei 

 tecti. Therefore in the 



3. ventral ascending spino-cerebellar tract secundary as well as 

 root-fibres of the n. octavus are found. 



To this tract the olivary bodies, probably do not participate. 



4. The secundary fibres in the systema dorsale issued from nucleus 

 ventrale, tuberculum acusticum and nucleus DEITERS follow the 

 dorsal way already traced by the root-fibres. But there parts from 

 the stria medullaris a new very important system 



5. MONAKOW'S transverse and ascendant secundary fibres. 



They cross the raphe ventrally from the fasc. long. post, reach 

 the dorsal layer of nucleus olivaris superior, and that of the nucleus 

 lemnisci ventralis. 



This decussatiori of MONAKOW'S fibres may be followed very far 

 proximally, but in proximal regions (between the motor nucleus 

 of the V th and the nucleus of the IV th nerve) they exit from the 

 tractus DEITERS ascendens. In distal regions DEITER'S descending 

 tract sends fibres among them. 



Together with root-fibres and secundary fibres of the ventral and 

 intermediary system, they go proximally in the lateral fillet in two 

 distinct bundles. They unite there with 



