442 



THE INTERMEDIATE PRIMATES 



both factors have contributed some additional prominence to the red nucleus 

 in gibbon. That its striorubral portion has undergone expansion might be 

 expected in an animal presenting such complex arboreal locomotion. That 



FIG. 209. GIBBON. LEN'EL OF THE SUPERIOR COLLICULUS. 



CEN, Central Gray Matter; cp. Cerebral Peduncle; ctt. Central Tegmental Tract; mf, Mesial Fillet; mgb, 

 Mesial Geniculate Body; noc. Nucleus Oculomotorius; nru. Nucleus Ruber; n'3. Oculomotor Nerve; pd, 

 Predorsal Bundle; pl, Posterior Longitudinal Fasciculus; ref, Reticular Formation; sbn, Substantia Nigra; 

 sc, Superior Colliculus; spt. Spinothalamic Tract. [Accession No. 141. Section 310. Actual Size 30 X 16 mm.] 



the cerebello-rubral portion of this nucleus has also undergone some expan- 

 sion may be inferred from the increased size of the dentate nucleus. Surround- 

 ing the nucleus on all sides, and lying lateral to the central gray matter 



