5^6 



THE HIGHER ANTHROPOIDS 



carried to a still fiirtluT extent in the higher anthropoids and man. Even in the 

 |)riinate order, therefori', this sign ol e\olutional progress in the ner\ous sys- 

 tem is elearU manifest. 



FIG. 239. ORANG-OUTANG. LEVEL OF THE SUPERIOR COLLICULUS. 



CEN, Central Gray Matter; ci>, Cerebral Peduncle; ctt, Central Tegmental Tract; mf, Mesial Fillet; mgb, 

 Mesial Geniculate Body; Noc, Nucleus Oculomotorius; nru, Nucleus Ruber; N3, Oculomotor Nerve; pd, 

 Predorsal Bundle; pl. Posterior Longitudinal Fasciculus; ruf. Reticular Formation; sbn. Substantia Nigra; 

 SC, SupcriorColliculus;SPT, Spinothalamic Tract ;TMT, Tract us Mesencepl),! I iciTrlfiemini. [Accession No. igg. 

 Section 636. Actual Size 26 X 13 mni.| 



The central gray matter fCen) surrounds tlie S\Ivian aciueduct, and 

 in its more ventral portion becomes speciahzed to form the oculomotor 

 nucleus (Noc). This nuclear collection is among the most important of 

 the cranial nerve groups, not because tfie muscular territory o\ cr which it 



