The Excitable Cortex of the Chimpanzee, Oran^-Utaii, and (Jorilla IGl 



I. I'ace Area. 



Face area so-called ini;,dit be better terined head area, since it includes 

 not only the face but toncrue, palate and fauces, and larynx. Its upper 

 boundary is usually with close accuracy marked by the level of the genu 

 inferius of sulcus post-centralis. In some chimpanzees and gorillas, and 

 especially, in our experience, in the orang. there is a tendency to the 

 appearance of a third genu of the fissure below the ordinary genu inferius. 

 And this third genu indicates approximately the level of subdivision of the 



Fig. 9.— Gorilla 1. A, left hemisphere ; B, right hemisphere reversed for comparison with 1 



so-called face area into an upper part in which movements of face proper 

 predominate, and a lower part in which are represented tongue movements 

 and movements of fauces, vocal cords, and palate. This third genu might 

 be called a labio-lingual genu (fig. 7a), because at it the area where lip 

 movements predominate as primary responses meets the area where tongue 

 movements as primary predominate. In the upper part of the face area 

 the movements elicited can bear for the most part an interpretation as 

 being partial movements in mimetic acts. In the lower part of the face 

 area the movements suggest for the most part their being parts of acts 

 subserving feeding, e. g. chewing, mastication, deglutition, etc. 



