224 



THE LOWER PRIMATES 



increase in coordinative control of the body as a whole. Such additional con- 

 trol in coordination would arise from the profound readjustments occasioned 

 by the assumption of the semi-erect posture and partial biped locomotion 



FIG. 124. MYCETES SENICULUS. LEVEL THROUGH MIDDLE OF PONS VAROLII. 

 CEN, Central Gray Matter; ctt. Central Tegmental Tract; cow. Ventral Spinocerebellar Tract; lf, Lateral 

 Fillet; mf. Mesial Fillet; mcp. Middle Cerebellar Peduncle; N4, Trochlear Nerve; N5, Trigeminal Nerve; 

 PD, Predorsal Bundle; pl. Posterior Longitudinal Fasciculus; pn, Pontile Nuclei; pns, Pons; pv, Pyramid; 

 REF, Reticular Formation; rst, Rubrospinal Tract; scp, Superior Cerebellar Peduncle; tur, Tractus Uncina- 

 tus of Russel (Hook Bundle). [Accession No. 148. Section 305. Actual Size 15 X 10 mm.) 



as well as from the fact that the animal is now able to sit upon its haunches 

 and in this position use its hands for various new purposes. Similarly the 

 scattered bundles of the pyramidal system, although disseminated amidst 

 the stratum complexum, present a greater degree of prominence in mycetes 

 than they do in lemur or marmoset. They afford the basis for a structural 



