INTERLACEMENT OF THE CEREBELLAR PEDUNCLES. 465 



diminishing as it descends, is yet still perceptible close to the 

 transverse sections of the latter columns which are distended 

 by the two nuclei they contain, and present a plexiform ap- 

 pearance externally, whilst they are compact internally. If, 

 therefore, Deiters is not justified on the one hand in denying 

 the presence of these fasciculi of the internal division of the 

 inferior peduncle of the cerebellum, which spring directly 

 from the cerebellum, it is possible they may not, on the other 

 hand, quite reach to the posterior column of the spinal cord, 

 but already pass as fibrse arcuatse into the oblongata above 

 the central canal. At all events, that columnar formation is 

 introduced between them and the corpora restiformia, that 

 enclosing the nuclei which distend it into the form of the 

 cuneate and slender fasciculi, actually passes into the posterior 

 column. We shall hereafter show that these last medullary 

 columns, which increase in size as they descend, are the crossed 

 continuation of the corpus restiforme, which are proportionately 

 exhausted. 



The inferior peduncle of the cerebellum, which, when super- 

 ficially examined, appears to be continuous with the posterior 

 column, is composed (1) of the corpus restiforme ; (2) of the in- 

 ternal division of the inferior crus cerebelli (Kleinhirnstiel) ; 

 (3) of the fasciculus cuneatus and the slender fasciculus. 



The complete juxtaposition of these occurs at the level of the me- 

 dulla oblongata, intermediate to the planes depicted in figs. 257 and 

 258. 



THE POSTERIOR TRANSVERSE SECTIONAL AREA OF THE 

 PROJECTION SYSTEM. 



The description of that interlacement of the projection 

 system which proceeds from the inferior peduncles of the cere- 

 bellum on both sides, must be preceded by a general view of 

 the mosaic arrangement of the former as it presents itself at 

 various heights. 



After this area of transverse section has become free in the 

 uppermost third of the pons from the interlacement of the 

 superior peduncle, where this appears on the external surface of 

 the posterior division of the pons, as the lateral wall of the 



VOL. II. H H 



