OF DENISOX UNIVERSITY 



63 



plane of its middle portion. The cells are fine examples of the miil- 

 cipolar type. 



This nucleus does not extend dorsad to the level of the sixth nu- 

 cleus, which is a relatively broad zone with little dorso- ventral extent. 

 The cells of the sixth nucleus lie with their axis from the median 

 toward the lateral line and their fibres evidently decussate. 



The same horizontal section (VII 6-19) displaying the nucleus of 

 the sixth shows the knee of the seventh, lying between it and the 

 median line and enveloping it anteriorly and posteriorly, as already 

 described. 



Scattered cells, apparently of the trigeminal system, lie dorsad 

 to the structures just described. 



Ventrally, the ventral nucleus of the fifth divides into two ill de- 

 fined clusters, the medio-caudad portion being approximated to the 

 root tract of the seventh, which latter subdivides into a larger cepha- 

 lad and smaller caudad portion. 



Nucleus of the p07is. The whole ventral part of the pons is filled 

 with cells, which here and there collect into considerable and distinct 

 nuclei. The cells are relatively short and paraxial with numerous pro- 

 cesses, the largest of which pass transversely, /. e. in the direction of 

 the pons fibres. These cells are comparatively small, but their nuclei 

 preserve a good size, thus: cells .030-. 035 in. diameter, nuclei .008 

 mm. The fibres can be traced from cells of the caudad portion of 

 the nucleus laterad and caudad for considerable distances to the root 

 of the fifth. (Plate XIX, Fig 3.) 



The sections at the level of the motor nucleus of the seventh 

 show that a part of the anterior portion of the pons nucleus is cut off 

 by the passage of the latero-ventral strands of the pyramids and lie 

 between those bundles and the pre-peduncular tract from the cerebellum. 

 Fibres from the cluster in question pass to unite with a nucleus of sim- 

 ilar cells at the immediate roots of the fifth. 



The seventh nucleus, as seen in horizontal sections at the level of 

 the emergence of its root is divided into three portions lying parallel 

 to the median line. The cells are beautiful illustrations of the multipo- 

 lar variety (Plate XIX, Fig. 5,) and afford ample suggestion, if not 

 proof that the fibrillar terminations of the {)rocesses described by 

 authors are due to the disi)Osition of connective tissue web in whic h 

 they hang. 



The Ccnbclluvi. Before adverting to the few observations we 



