68o 



THE HIGHER ANTHROPOIDS 



LEXEL OF THE SUPERIOR COLLICULUS (PIG. 309) 



Here the general contour of the section has undergone marked altera- 

 tion primarily due to the divergence of the cerebral peduncles (CP). 



FIG. 309. GORILLA. LEVEL OF THE SUPERIOR COLLICULUS. 



CEN, Central Gray Matter; cp. Cerebral Peduncle; err, Q-ntral Tegmental Tract; mf. Mesial Fillet; mgb. 

 Mesial Geniculate Body; NOC, Nucleu? Oculomotorius; nrl. Nucleus Ruber; N3, Oculomotor Ner%e; PD, 

 Predorsal Bundle: pl. Posterior : a! Fasciculus; ref. Reticular Formation; sen. Substantia Nigra; 



sc, Superior CoUiculus; spt, Spin^L.„ Tract. [Accession No. J. D. Section 885. Actual Size 30 X ij mm.] 



In the dorsal region are the two fairly prominent elevations forming the 

 superior colliculi (SC). The section is further characterized by the appear- 

 ance near the center, in the reticular formation, of a large specialized 

 nuclear mass, the nucleus ruber (NRu). The superior colliculi contain 

 indications of being the vestige of the once conspicuous optic lobes in the 



