218 D. DAVIDSON BLACK 



section it is seen that the olives differ from the normal in showing 

 three very definite outpouchings — a dorsal, a ventral and a 

 lateral. The fibers arising from the olive are quite lacking in 

 myelin. The mesial and dorsal accessory olives are present in 

 practically normal relations. 



Lemniscus system. The decussatio lemniscorum (DecL), the 

 stratum interolivare lemnisci (S.i.l.) and the mesial lemniscus 

 {L.m.) up to the level of the anterior portion of the red nucleus 

 {Nu.r.) are essentially normal. At about the caudal end of the 

 nucleus ruber, a well marked strand of fibers is given off from the 

 lateral part of the main sheet of the fillet. This has been identi- 

 fied as the superior lemniscus {L.s., fig. 39). It passes up to end 

 in the region of the superior colliculus. Beyond the nucleus 

 ruber the lemniscus cannot be traced as a definite fiber system. 

 Here its fibers become scattered and are lost in the dorso-lateral 

 portions of the thalamic mass. 



Fasciculus longitudinalis medialis (F.l.m.). This fiber system 

 is prominent throughout the series caudad to the posterior com- 

 missure. It is the most completely medullated tract in the brain 

 stem and on this account can be easily separated from the lem- 

 niscus in the stratum interolivare. Its relations throughout are 

 normal and it is traceable, together with fibers from the stratum 

 album profundum of the midbrain, into the posterior commissure 

 Above the oculomotor nucleus {Nu.N.III) it is related to a well 

 developed nucleus (Ny. f.l.m., figs. 38 to 40) having the same rela- 

 tions as the nucleus of the posterior longitudinal bundle in 

 normal sections (Darkschewitsch). 



Corpus trapezoideum {C.t., figs. 35 to 37). The trapezoid body 

 and the lateral lemniscus {Ld. figs. 33 to 37) together with their 

 associated nuclei are quite normal in their relations and course. 

 The lateral lemniscus terminates in the well marked nucleus of 

 the inferior colliculus (Nu.c.i., figs. 33 to 36). No brachium of 

 the inferior colliculus is present. 



Cerebellum and peduncles. The cerebellum shows a well de- 

 veloped dentate nucleus (Nu.d.) together with globose {Nu.g., 

 figs. 31 to 32) emboliform {Nu.emb., figs. 32 to 34) and roof nu- 

 clei. There are almost no medullated fibers to be found in the 



