4i6 



THE INTERMEDIATE PRIMATES 



more closely with the group here identified as intermediate primates. Cer- 

 tainly, the superlicial appearance of the gibbon's cerebral hemisphere places 

 between it and the more highly complex endbrain of the great anthropoid 



FIG. 195. LEFT LATERAL SURFACE OF BRAIN, HYLOBATES HOOLOCK. 

 [Actual Length, 73 mm.| 



Kev to Diagram, cerebl.. Cerebellum; obl., Oblongata; sulc. occip., Sulcus Occipitalis; SULC. occip. 

 LAT., Sulcus Occipitalis Lateralis; sulc. precnt. inf., Sulcus Precontralis Inferior; sulc. ret. sup.. Sulcus 

 Rctroccntralis Superior; sulc. simiarum. Sulcus Simla rum. 



apes a wide interval, so wide as to justify the opinion that in descent, the 

 hneal relation between the gibbon and the anthropoid, however direct, must 

 be quite remote. 



THE CEREBELLUM 



The cerebcHum I^ears out this impression in conclusive manner. Its 

 tentorial surlace shows that marked convexity or gabling which culminates 

 in a well-defined vermal ridge-pole. This feature is characteristic of intermedi- 

 ate and lower primates, but gradually disappears in the higher anthropoids. 

 On the tentorial surlace of the cerebellum the interfolial fissures pass from 

 the vermis to the lateral lobe without sulcal interruption, while on the occip- 

 ital surface, a paramedian sulcus upon either side of the vermis interrupts 

 the folial sulci in their passage from the median to the lateral expansions of 



