INFERIOR PEDUNCLE OF THE CEREBELLUM. 463 



from the opposite middle crus between the longitudinal fasci- 

 culi, as interlaced transverse fasciculi, they cross the middle 

 line a second time in the opposite direction, as fasciculi of the 

 deep layers of transverse fibres, in order to pursue a recurrent 

 course in the middle crus from which they were derived. The 

 following theory of the course of the fibres of the pons is the 

 only one that includes the facts above mentioned: Every 

 fasciculus of the middle crus cerebelli crosses the middle line 

 in the superficial layer of transverse fasciculi, then inter- 

 laces with the anterior longitudinal fasciculi of the opposite 

 side, becoming connected with them by means of the grey 

 matter. And now encircling them on the outer side, it 

 passes behind the longitudinal fasciculi into the deep layer 

 of transverse fibres, crosses the middle line once more, and 

 runs back again into the cerebellum, through the same 

 middle crus in which it was first contained. If we pro- 

 ceed on this view of the projection system, the course may 

 thus be stated : that every fasciculus of the cerebral peduncle 

 terminating in the anterior division of the pons is repre- 

 sented by tivo fasciculi of the opposite middle peduncle of the 

 cerebellum, of which one runs through the superficial, the other 

 through the deep layer of transverse Jibres of the pons. Thus each 

 crusta of the cerebral peduncle is connected with the opposite 

 hemisphere of the cerebellum by the opposite processus e cere- 

 bello ad pontem, just as it is connected with the opposite half 

 of the spinal cord by the decussation of the pyramids. Since 

 the crusta of tne cerebral peduncle constantly participates in 

 atrophy of the cerebral hemisphere of the same side, this 

 crossed connection of the cerebellum with the cerebral hemi- 

 spheres may perhaps explain the frequent complication of 

 that atrophy with crossed atrophy of the hemispheres of the 

 cerebellum. 



THE INFERIOR PEDUNCLE OF THE CEREBELLUM (KLEINHIRN- 

 SCHENKEL) AND THE PROLONGATION OF THE TEGMENTUM 



(HAUBE). 



The pedunculi cerebelli contain the third set of fasciculi that 

 interlace in their transverse course with the longitudinal fasciculi 



