102 THE LOWER PRIMATES 



throughout the stem show an indecisive differentiation. This feature is partic- 

 ularly noted in the cranial nerves whose emergent fibers by comparison 

 with other primates seem coarse and heavy. The nuclear territories and tract 



FIG. 



TARSIUS SPECTRUM. LEVEL OF THE FIRST CERVICAL SEGMENT. 



CEN, Central Gray Matter; cb, Column of Burdach; CG, Column of Goll; dg, Dorsal Gray Column; dt, 

 Deiterso-spinal Tract; fle. Dorsal Spinocerebellar Tract; cow, Ventral Spinocerebellar Tract; py, Crossed 

 and Uncrossed Pyramidal Tract; ref, Reticular Formation; rst, Rubrospinal Tract; spt, Spinothalamic 

 Tract; ven, Ventral Gray Column. [Accession No. 210. Section 26. Actual Size, 3X2 mm.] 



regions ahke are indefinite in their boundaries. Some noteworthy speciahza- 

 tions appear in particuhir mechanisms, such, for example, as the pronounced 

 expansion of the ventral gray cohimn connected with the origin of the spinal 



