478 



.1. n. JOHNSTON 



witliiii t.liis ai'oa. As the whole area is only a few millhneters in 

 extent, it is obvious that ^I'cat care must be exercised in accepting 

 as conclusive any api^arent indications of special function of 

 particular parts of this area. For this reason I mention only 

 tentatively and with reserve that leg movements have been 

 obtained most often from the anterior part of this area and eye, 

 jaw and neck movements from the lateral portion. Further 

 experiments will be made to determine whether a locahzation 

 within the niotoi' area clearly exists. In certain experiments 



Fig. 1 Sketches of the dorsal surface of the right hemisphere of the turtle 

 (left) and lizard fright) on which the motor area is shaded. 



the eye and jaw^ movements were homolateral only or more 

 frequently, while the neck and leg movements were mostl}^ 

 heterolateral. 



Excitation of the dorsal ventricular ridge in the turtle was 

 carried out by cutting away the whole dorsal pallium and apply- 

 ing the electrodes to the ventricular surface of the ridge. Muscu- 

 lar responses were often obtained, such as retraction of the eye- 

 ball, contraction of temporal muscle and twitching of fore leg, 

 but there is the double danger of spread of stimulus to the 

 closely adjacent pallial thickening and of stimulation of the 

 underlying crus. 



