< 'HAP. ii.] 



THE BRAIN. 



961 







little distance dorsal to that nucleus, and then descends again 

 ventrally, passing to the lateral side of its own nud. us, between 

 it and the ascending root of the fifth ( Va) ; it thus gains the 

 surface of the brain at the hinder margin of the pons, lateral to 



trP gr.P 



FIG. 112. THROUGH THE PONS AT THE EXIT OF THE FIFTH 

 NERVE. (Sherrington.) 



(In the line 112, Fig. 108.) 



C. R. Kemains of restiform body. S. P. superior peduncle of the cerebellum. 

 F. m. median, F. 1. lateral Fillet. T. R. tegmental reticular formation. 

 tr. P. superficial transverse fibres of the Pons. I. posterior longitudinal 

 bundles. V. s. superior vermix ; sections of three folia are shewn, one being 

 detached; between them the intervening sulci laid open by the section are 

 seen. VI. a. valve of Vieussens or anterior velum, r. raphe. Py. Pyramidal 

 fibres, gr. P. grey matter of the Pons. s. o. superior olive, t. placed on 

 the left side indicates the position of a bundle of longitudinal fibres which 

 may be traced forward into the subthalamic regions. V. m. motor nucleus, 

 V. s. sensory nucleus, and V. roots of the fifth nerve. 



4th, fourth ventricle; shading of central grey matter omitted as in Fig. 111. 



the abducens, opposite the front end of the groove between the 

 olivary body and the restiform body. As it thus encircles the 

 nucleus of the abducens, it looks as if it were receiving fibres 

 from that body ; but the evidence goes to shew that these fibres 



612 



