THE PONS AND THE CEREBELLUM. 



129 



the pons which pass at right angles to those of the crusta over 

 to the opposite cerebeUar hemisphere. 



Aside from this it is not certain, and not even probable, 

 that all the fibres of the pons are to be regarded merely as con- 

 tinuations of the cerebral fibres. The arms of the pons (brachia 

 pontis) contain more fibres than are conveyed to it by the crusta. 

 Moreover, many of them acquire medullary sheaths at a time 



fa se/vr 

 3us 4. Vorderhirn. 



FIG. 74. 

 Diagram of a section through the pons and cerebellum. 



Haube, Tegmentum. Fasern aue d. Vorderhirn, Fibres from the fore-brain. 



when no single fibre of the crusta is so enveloped. This con- 

 dition I have seen in cats. 



Although the pes pedunculi is pierced through and through 

 by the fibres of the pons, and in part diverted into the cere- 

 bellum, yet the tegmentum is continued through the region of 

 the pons with very little change. In the last section through 

 the quadrigeminal region we distinguish the following as the 

 principal structures of the tegmentum (compare Fig. 62) : 



1. The gray substance around the aqueduct, together with 

 its nerve-nuclei. 



