196 



LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



have also been called the pyramidal arciform fibres (Fig. 113, 

 front view). They inclose a small nucleus, the nucleus arci- 

 formis (Fig. 118). Thus there pass to the restiform body from 

 the spinal cord, 1, the direct cerebellar tract; 2, fibres of the 

 posterior column on the same side; 3, fibres probably from the 

 opposite posterior column.* 



FIG. 117. 

 Section through the medulla oblnngata of an embryo of the twenty-sixth week. 



Hintrr-Hurn, Post. horn. 



KlfinJiirn Balm, Cerebellar tract. 



Oliv. Zwiach. Schicht, Inter-olivary layer. 



Seitenstrang, Lateral column. 

 \~nrtler-Jforn, Anterior horn. 

 Vorder-Strung-Rent, Remnant of anterior column. 



Ill the embryonal period depicted in Fig. 110, only the 

 fibres from the spinal cord are medullary. Thus we can clearly 

 distinguish the extent and location of this portion of the pos- 

 terior cerebellar peduncle. The different arciform fibres are 

 also shown in Fig. 118. 



The restiform bodies, however, contain, besides the fibres 

 from the spinal cord, a second and much larger system, which 



*The fibres mentioned under the heading 3 become medullary months before the 

 pyramids and olivary bodies, probably at the same time as the posterior columns. 



