H^LOBATES HOOL.OCK, THE GIBBON 433 



LE\'EL OF THE CEREBELLAR NUCLEI (FIG. 20^) 



At this level the cerebelhim eontains evidenee of a deeisive advance. 

 This advaiiee atlects the eerei^eHar nuelei and partieularly the nucleus den- 



FIG. 



104. 



GIBBON LE\'EL OF THE CEREBELLAR NUCLEI. 



icp, Inferior Cerebellar Peduncle; mf, Mesial Fillet; ndt, Cerebellar Nuclei, Lateral Group; nfg, Cerebellar 

 Nuclei, Mesial Group; n8. Auditory Nerve; pv. Pyramid; ref. Reticular Formation; scp, Superior Cere- 

 bellar Peduncle. (Accession No 141. Section 151. Actual Size 19 X 12 mm.) 



tatus (Ndt ). For the first time this nucleus shows some of the tendencies 

 in its development which foreshadow its ultimate configuration in the higher 

 primates. In the species lower than gibbon, the dentate nucleus has had a 

 more ditfuse and somewhat amorphous appearance — amorphous at least in 

 that it does not present any of those distinctive features which mark it in 

 the great apes and man. A suspicion of the tendency to become convoluted 

 may be detected in the baboon and macacus. In general, however, this 

 tendency in both of the latter species is confined to ca^cumscribed and quite 



