440 



THE INTERMEDIATE PRIMATES 



nucleus trochlearis (Ntr) from which the fourth cranial nerve arises (N4). 

 In the lateral border of the central gray matter are the scattered bundles 

 forming the tractus mesencephalicus trigemini (Tmt), while in a ventral 



FIG. 208. GIBBON. LEVEL OF THE INFERIOR COLLICULUS. 

 CEN, Central Gray Matter; ctt. Central Tegmental Tract; ic. Inferior CoIIiculus; lf. Lateral Fillet; mf> 

 Mesial Fillet; ntr, Trapezoid Nucleus; N4, Trochlear Nerve; pl, Posterior Longitudinal Fasciculus; pns, 

 Pons; pv. Pyramid; rst. Rubrospinal Tract; scp, Superior Cerebellar Peduncle; spt, Spinothalamic Tract; 

 TMT, Tractus Mesencephalic! Trigemini. [Accession No. 141. Section 278. Actual Size 16 X 15 mm.] 



