6^8 



THE HIGHER ANTHROPOIDS 



of the ncuraxis. Tlic p3'ramidal system (Py) appears more massive 

 than in any of the primates. The decussation (Pyx) shows the fibers 

 passing from a ventromesial position across the median line to a dorsolateral 



FIG. 297. GORILLA. LE\ EL OF THE mUAMlUAL DECUSSATION. 

 CB, Column of Burdach; CEN, Central Gray Mallir; c;g. Column of Goll; dt. Deiterso-spinal Tract; fi.e. 

 Dorsal Spinoccrclxllar Tract; cow, Ventral Spinocerebellar Tract; hf;i., Spino-olivary Tract of Hclweg; 

 NR, Nucleus of Rolando; pv, Pyramid; pvx. Pyramidal Decussation; rst. Rubrospinal Tract; spt, Spino- 

 thalamic Tract; trd, Descending Trigeminal Tract; \ i-.\, Ventral Gniy Column; xpi. Crossed Pyramidal 

 Tract. (Accession J. D. Section 100. Actual Size 13X9 mm.| 



position on tiie opposite side. Tlie decussating fibers separate the central 

 gray matter (Cen) from the \entral >j;ra\ niattt'r ( Ven). Passing through 

 the reticuhir formation are some of thi' emi'rgmg hhers ol the ele\i'iith oi' 

 spinal accessory ner\e. ScatttTcd through the dorsal portion ol the reticular 



