SUMMARY OF STRUCTURES 



465 



Coefficients of the Entire Vestibular Area in the Intermediate Primates 



Even more interesting is tlie comparison of the intermediate primates 

 with those of the lower group. This contrast shows how nearly equal the bal- 

 ancing problems in all of these primates are. In this respect, however, mycetes 

 and tarsius exceed all of the other species. Here again, as in the case of 

 the sensory nuclei of the dorsal column, it is undoubtedly the additional 

 motor capacity and locomotor speciaHzation that bring into play new ranges 

 of motion connected with balancing. These additions demand a more effec- 

 tive mechanism for this function. But among the intermediate primates the 

 gibbon, because of its pecuhar arboreal locomotion, has a shghtly more differ- 

 entiated mechanism than its congeners in this group. 



V. The Cerebellar Nuclei in Their Relation to the Coordination of 



Movements, Especially the More Complex Movements 



of the Upper Extremities 



Employing the dentate nucleus of the cerebelhim as an important repre- 

 sentative of coordinative function in the brain, it appears from a comparison 

 of this structure in the intermediate primates that the baboon shows a some- 

 what greater speciahzation than either of the other forms. This comparison, 

 which slightly favors the baboon, is somewhat perplexing at first glance. 

 Talcing into consideration the fact that this animal is speciahzed for rapid 

 and ahiiost perfect quadrupedal locomotion upon the ground, and at the 

 same time has ahnost equal capacity for chmlDing in rocky places and even 

 in the trees, it becomes evident that its musculature is in need of a high degree 



