OF DEXISON UNIVERSITY. 45 



small fibres, the immediate derivitives from a longitudinal bundle ap- 

 pearing far caudad in the medulla and anteriorly covered by the longi- 

 tudinal bundle of the fibrae arciformes. A smaller longitudinal bundle 

 lies in the tuberculum Rolandii. The smaller root springs from a nu- 

 cleus of large multipolar cells, like those of the facialis, lying below 

 the floor of the ventricle. Its fibres curve dorsally, then ventrally and 

 laterally to their exit. A part, however, of the trigeminus fibres can 

 be traced to the nucleus of the trochlearis. The cells of ih^/rochltaris 

 nucleus are rounded and have few processes. The nucleus is elon- 

 gate, and Its fibres pass dorsally and caudad to the decussation in the 

 valvula cerebelli. 



The Cerebellum. The medulla is connected with the cerebellum 

 by the fibr« arciformes, there being no connection via corpora resti- 

 form. The entire mass of the crura cerebelli ad corpora (juadrigemina 

 is derived from the cerebellum. 



In the /tz/-i-/f^/^;/t7//<;7;w the pyramids appear quite lateral, while 

 the anterior longitudinal fasciculi occupy a place between them and 

 are only separated from each other by the substantia cinerea posteriora 

 media. In addition there is a dorsal fascicle, and isolated fibres from the 

 cerebellum. 



The gray substance between the longitudinal bundles is composed 

 of a granular basis with small round or spindle cells and contains the 

 following nuclei. The nucleus peduncularis consists of a lower por- 

 tion composed of numerous small cells (.012-. oi6 mm.) and an upj)er 

 smaller nucleus, with large multipolar cells (.04 mm). This nucleus 

 occupies a lateral, ventral position below the nucleus of the oculomotor, 

 which its upper portion resembles. 



The corpora quadrigemina, thalami and optic region wrre not 

 fully studied. 



The corpora striata consist of mingled gray and while umUh. hk 

 side nearest the ventricle being almost altogether gray, and the lateral 

 portion united with the hemispheres is full of fibre bundles. The gray 

 substance contains small round or fusiform cells with exceedingly fine 

 processes and measuring .008-012 mm. 



The hemispheres are evidently zonary, the outer layer having a 

 thickness of 0.5 mm., followed by a gray layer reposing in turn upon 

 the inner white. The gray matter of the corte.x consists of three lay- 

 ers of cells: first, an outer layer of .small cells .008-.016 mm. long, 

 and closely aggregated; second, the layer of large cells .04 mm. long, 



