H\LOBATES HOOLOCK, THE GIBBON 



425 



ity has occasioned a notable mcrenicnt in consequence ot the annual's high 

 specialization for arboreal life. The ultimate formula of the elements in 

 the dorsal field of the great apes and man is here more nearly approached 





FIG. 200. GIBBON. LEVEL OF THE CAUDAL EXTREMITY OF THE INFERIOR OLI\ E. 

 CB, Column of Burdach; cen, Central Gray Matter; dt, Deiterso-spinal Tract; fle, Dorsal Spinocerebellar 

 Tract; cow, Ventral Spinocerebellar Tract; 10, Inferior Olive; mf. Mesial Fillet; nb, Nucleus of Burdach; 

 NBL, Nucleus of Blumenau; ng. Nucleus of Goll; nr, Nucleus of Rolando; pv, Pyramid; ref, Reticular 

 Formation; rst. Rubrospinal Tract; spt. Spinothalamic Tract; trd, Descending Trigeminal Tract. [Acces- 

 sion No. 141. Section 16. Actual Size 9X8 mm.] 



than in any ot the primates below this stage. Numerous coarse bundles 

 of arcuate fibers arising in the nucleus of Goll pass forward toward 



