46o THE INTERMEDIATE PRIMATES 



those of the macacus or the baboon, either in complexity of organization or 

 degree of dexterity. This marked speciaHzation in the regulation of simul- 

 taneous movements in eye, hand and head seems to be superlUious in so far 

 as the gibbon's I:)ehavioraI attainments are concerned. There is that, however, 

 in the skilled motor performances of this animal which may call for such 

 spontaneous coordination of oculo-cephalo-gyric movements as the gibbon 

 manifests. The prodigious swings which it makes from branch to branch in 

 its flight-like locomotion demand, above everything else, the most accurate 

 timing in the coordination between the eye and hand. 



The planimetric coeOicients of macacus and baboon are practically 

 equal; whatever little difference there may be favors the macacus. The 

 coefficients of the inferior olivary nucleus in the mtermediate prmiates are 

 given in the appended table: 



Coefficients of the Inferior Olive in the Intermediate Primates 



Contrasted with the lower primates the inferior olive shows a gain in 

 prominence in the intermediate forms. Mycetes, however, as might be expected, 

 approaches fairly close to the intermediate primates in this regard. It is 

 strikingly inferior to the gibbon whose high degree of olivary expansion 

 furnishes an element upon the strength of which it may lay claim to some 

 degree of lineal propinquity to the three great anthropoids. 



III. The Dorsal Nuclei in Their Relation to Discriminative 

 Sensibility in the Extremities and Tail 

 The nucleus of Goll, representative of the discriminative sensory influx 

 from the tail and lower limbs, furnishes convincing contrast in the inter- 



