176 THE LOWER PRIMATES 



tion in coordinative control. This section also shows the caudal extremity of 

 a large mass of gray matter situated ventral to the mesial fdlet (Mf), 

 namely, the substantia nigra (Sbn). This mass, as in lemur, assumes 



MARMOSET. LEVEL OF THE SUPERIOR CEREBELLAR 

 PEDUNCULAR DECUSSATION. 

 CEN, Central Gray Matter; cp, Cerebral Peduncle; ctt. Central Tegmental Tract; mf. Mesial Fillet; NOC, 

 Oculomotor Nucleus; nru, Nucleus Ruber; N3, Oculomotor Nerve; pd, Predorsal Bundle; pl. Posterior 

 Longitudinal Fasciculus; ref. Reticular Formation; sc, Superior CoIIiculus; sen. Substantia Nigra; xscp. 

 Decussation of the Superior Cerebellar Peduncle. [Accession No. 146. Section 162. Actual Size 9X7 mm.] 



large proportions. If the substantia nigra is concerned with the control of 

 certain automatic associated movements, as has been presumed by manj^ 



