230 THE LOWER PRIMATES 



structure of the internal capsule (Cin) is indicative, as are the cerebral 

 peduncle and the pons Varolii, of the high degree of neokinetic expansion 

 exhibited by these monkeys. The behavioral patterns have become greatly 



FIG. 128. MYCETES SENICULUS. LEVEL OF THE ANTERIOR COMMISSURE. 



AC, Anterior Commissure; cin, Internal Capsule; len. Lenticular Nucleus; NC, Caudate Nucleus; th, 



Thalamus; vl. Lateral Ventricle. [Accession No. 148. Section 575. Actual Size 28 X 13 mm.] 



amplified in consequence of those new capacities made available by quad- 

 rumanous differentiation. To this new range of capacity should also be 

 added those facilities of motion made possible through the prehensile tail, 

 also spoken of as the fifth hand. Bordering on the outer surface of the 

 internal capsule are the two major divisions of the lenticular nucleus, 

 namely, the globus pallidus (Gib) and the putamen (Put). 



