ii8 



THE LOWER PRIMATES 



the nucleus emboliform Is ( NDt). It is impossible to discern distinctive bound- 

 aries between these two nuclear masses. Even by means of reconstruction 

 these nuclei do not disclose any distinct individualization. It is hence deemed 



FIG. 57. TARSIUS SPECTRUM. LEVEL OF THE CEREBELLAR NUCLEL 

 CJR, Juxtarestiform Body; ctr, Trapezoid Body; dt, Deitersal Tract; Govv, Ventral Spinocerebellar Tract; 

 icp. Inferior Cerebellar Peduncle; mf, Mesial Fillet; nd, Deitersal Area; ndt, Cerebellar Nuclei, Lateral 

 Group; NFG, Cerebellar Nuclei, Mesial Group; nr. Nucleus of Rolando; nsc, Nucleus of Schwalbe; n6, 

 Abducens Nerve; N7, Facial Nerve; n8. Eighth Nerve; pl, Posterior Longitudinal Fasciculus; pd, Predorsal 

 Bundle; py. Pyramid; ref, Reticular Formation; rst. Rubrospinal Tract; so, Superior Olive; spt. Spinothala- 

 mic Tract; trd, Descending Trigeminal Tract; tub, Tuberculum Acusticum. [Accession No. 210. Section 

 163. Actual Size 8X5 mm.) 



advisable to designate this collection as the dentate mass. The outstanding 

 feature regarding it is its lack of definition and the entire absence of any 

 tendency toward convokition which characterizes this nucleus in the higher 

 primates. In tarsius the dentate nucleus is small and, as might be interred 

 from it, the lateral lobes of the cerebellum are poorly developed. This con- 

 dition indicates an animal provided with a low degree of eoordinative control, 



