SIMIA SATMU'S, THE ORANG-OUTANG 517 



mass, till' nucli'Lis facialis. From ihis lacial nucleus many myrlinizccl 

 libers pass backward ami inward, toward the Moor of the fourth \entricle 

 where the\ beconu' assi'inbled to lorm the second portion of the emergent 

 course ol the stAcnth nerw. In tlu'ir usual \entral area are the libers con- 

 stituting the p\ ramid ( Pv), now surrounded b\ a large nuclear aggrega- 

 tion, the caudal e\trcmit\ of the pontile nuclei ( PN ). Lying in a 

 position more trans\erse than in thv lower sections, is a bundle of libers mark- 

 ing the boundar\ between the tegmentum and the basis, the nu-sial 

 fillet (Ml ), through w Inch pass the di'cussating libers ol the corjius trapezoid- 

 vum. 1 hus at this le\el it is possible to make a lairly accurate comparison 

 ol the \()lumc ol im|)ulses passing o\er the mesial lillet and the pyramid. 

 Both ol these fasciculi appear more ample than in the lowi-r primates, a 

 conclusion which would |ustil\ the impression that orang is an animal inort' 

 highly endowed in discriminatiw sensibilitx' and also m \'ohtional control of 

 motion. 



LEVEL NEAR THE CAUDAL LIMIT OF THE PONS \AROLII SHOWTNC. THE 

 EMERGENT FIBERS OF THE SL\ IH NER\ E (FIG. 235) 



Heri' the section presents those marked changes incident to the appear- 

 ance ol tlu' t\pical pontile stratification. The pons consists of the stratum 

 suiK'rficialc; the stratum coinplexum, containing the large mass of jjoiitile 

 nuclei, trans\erse liln'rs and the scatterttl bundles of the j)\ramidal system, 

 and thestratum prohmdum compost'd largelx ol tiansxerse libers. The general 

 size of tht' pons Varolii, especiall\' of tlu' jjontile nuclei, implies an animal 

 possessed of a high degree of coordinati\e control oxer tlu' more complex 

 acquired moxemeiits. it indicates an ample communication between several 

 areas of tin- neopallium and the lati'ral lobes ol the cerebellum. The pallio- 

 poiito-ccrebellar system, as has alread\ been shown in |>revious discussions, 

 is characteristic of the mammalian brain alone, its predominant de\elo])- 



