RECONSTRUCTION OF TROGLOD\ TES GORILLA 693 



is clc'\rl()|X'cl ;i distinct intcrnu'diatc nuclear layer lyinjj; between the superfi- 

 cial vi'Utral and the dorsal deep strata. There arc also suhsidiar\ la\'ers of 

 gray matter which pass more or less as concentric arcs about the common 

 ceiitt-r from the mesial to the lateral buttrt'ss, separatinii; the pyramidal 

 tract and the pallio-])ont ile libers into man\ smaller constituent groups of 



tract and tlie pallio-])ont ile libers into man\ smaller constituent groups ol 

 libers. This arrangement produces an intricate lace-like appearance in the 

 |)ontile nucleus. Thi' lateral surlace ol this nucleus is extrenu'l\ irregular 

 due to the emergence trom it ol numerous liber buiulli's w hich constitute the 

 middle cerebellar peduncle. This is especially true in the mid-pontile region 

 where there appears a well-marked hiatus betw ecu the intermediate and deep 

 layers ol the nucleus. From this opening a large mass of libers enu-rges to 

 lorm the mam bulk ol tlu' middle cerebellar peduncle. 



Ccphaiicall\ , as the pontili' nucleus becomi's incompk'te along its lateral 

 margin, tlu' mesial buttress is continued upward in contact w ith the reticular 

 lorm at ion to the |u net 1011 of the hmd- and midbrain. At this i)oint the pontile 

 nucleus comes to an vnd. Its deep layer is continued upward to give support 

 to the substantia nigra. The pontile nucleus is in mlimate contact mesiall\' 

 and laterall\ with tlu- \entral surlace of the ri'ticular tormation. Between 

 these two points, however, it is separated by longitudinal bundles m the 

 jjcriphery ol the tegmental reticular formation. In the mid-pontile region at 

 the point Irom which the large liber mass t'lnerges Irom tlu' poiitik' nucleus, 

 the di'cp layer is continued as a delinite structure in the reconstruction and 

 can be seen to fuse with the ventrolateral angle ot the reticular tormation. 



The ViiSTiBUL.A.K Complex 



The \estibular com|)Ie\ makes its appearance in the reconstruction as 

 the nucleus of Deiti'rs, here de\elo])ing in its usual triangular lorm between 

 the mesial surlace of the upptr extremity of the ulicIcus of Burdach and the 

 subepend\mal gra\' matter lining the lloor ot the lourth \entricle. 



