MOTOR FUNCTIONS OF CEREBRAL CORTEX OF CAT 205 



for many of the types the fields on the two sides appear to have 

 little relation to each other. An excellent example is given in 

 figure 28, which shows the locations for rotation of the fore limb. 

 On the left cortex, the field for outward rotation is adjacent to 

 and external to the outer end of the crucial sulcus, while on the 

 right side it is close to the anterior angle of the lateral fissure. 

 The field for inward rotation of the fore limb, figure 22, is 

 shown to be adjacent to and external to the end of the crucial 

 sulcus on the left side, and near the upper end of the supraorbital 

 fissure on the right side. The field for flexion of the toes of the 

 hind foot, figure 43, on the right side, is in the region adjacent 

 to the crucial sulcus, on the left in the region about the anterior 

 end of the lateral fissure. The field for movements of the 

 mandible, figure 48, is, on the right side, between the outer end 

 of the crucial and the anterior end of the lateral fissure, on the 

 left side it is internal to the upper end of the supraorbitalis. 

 The field for retraction of the tongue, figure 50, has a distribu- 

 tion on the two sides similar to that for the movements of the 

 mandible. The field for sideward movements of the tail, figure 

 59, is, on the right, immediately posterior to the inner end of the 

 crucial sulcus and immediately anterior to the outer end, but on 

 the left it is between the outer half of the crucial and the anterior 

 limb of the lateral. 



On the other hand, for certain types of movement, the corti- 

 cal fields are quite symmetrically placed on the two sides. The 

 following examples of such symmetrically placed fields may be 

 mentioned : The field for retraction of the elbow, figure 24, occu- 

 pies, on the right and left sides, the area bounded by the coronal, 

 supraorbital and anterior limb of the lateral fissure. The field 

 for extension of the fore knee, figure 27, from the middle of the 

 crucial sulcus on both banks to the coronal fissure, in a wedge 

 shaped area. The field for flexion of the toes of the hind foot, 

 figure 43, adjacent to the crucial sulcus on both banks and to the 

 anterior limb of the lateral fissure. The field for movements of 

 the eye, figure 45, internal to the supraorbital fissure. The field 

 for movements of the lips, figure 47, same as for movements of 

 the eyes. 



