128 



THE LOWER PRIMATES 



If comparison were made between tarsius and some of the lower 

 mammalian forms — carnivores, rodents and even marsupials — on the 

 basis of the cerebral peduncle, the tarsier would be forced into a position 



FIG. 60. TARSIUS SPECTRUM. LEVEL OF THE SUPERIOR COLLICULUS. 

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

 Mesial Geniculate Body; N3, Oculomotor Nerve; nru, Nucleus Ruber; noc. Oculomotor Nucleus; pd, 

 Predorsal Bundle; PL, Posterior Longitudinal Fasciculus; ref. Reticular Formation; sbn, Substantia Nigra; 

 sc, Superior Colliculus; spt, Spinothalamic Tract. [Accession No. 210. Section 250. Actual Size 9X7 mm-1 



of relative inferiority. It may perhaps, to some extent at least, excel certain 

 of the marsupial species. Its primitiveness is again emphasized by the extreme 

 dimensions of the superior colhcuhis. This structure, because of its size, by 



