114 THE LOWER PRIMATES 



but of a highly specialized order. This field, formerly occupied by the nuclei 

 of Goll and Burdach, has given place to the nucleus of Deiters (ND) 

 and the nucleus of Schwalbe (NSc), both of which have acquired remark- 



FIG. jj. TARSIUS SPECTRUM. LEVEL OF THE \'ESTIBULAR COMPLEX. 



CTT, Central Tegmental Tract; dt, Deiterso-spinal Tract; GOw, Ventral Spinocerebellar Tract; ICP, Inferior 

 Cerebellar Peduncle; mf, Mesial Fillet; nab, Nucleus Abduccntis; nd, Deiters' Nucleus; nf, Facial Nucleus; 

 NR, Nucleus of Rolando; nsc, Nucleus of Schwalbe; pd, Predorsal Bundle; fl, Posterior Longitudinal 

 Fasciculus; pv. Pyramid; ref, Reticular Formation; rst. Rubrospinal Tract; spt. Spinothalamic Tract; 

 TRD, Descending Trigeminal Tract. [Accession No. 310. Section 140. Actual Size 7X3 mm.] 



able dimensions as compared with other primates. The Dcitersal area in 

 tarsius is larger than in the cat, rabbit, kangaroo, horse, dog, or any of the 

 primates. The triangular nucleus of Schwalbe, while large, is perhaps not so 

 striking in comparison with other forms. 



To fmd such extensive development in the balancing mechanism of 

 tarsius implies that the animal requires a most highly efficient apparatus for 

 equilibrium. The behavior of tarsius bears out this supposition. There is 

 nothing perhaps in its postural requirements while at rest which may sug- 



