440 



Messrs. Y. Horsley and E. A. S chafer. [Mar. 20, 



the marginal convolution marked I, I 7 , extending from just in front of 

 the small vertical sulcus y to a point on a level with the anterior third 

 of the small antero- posterior sulcus x, excitation is followed by either 

 movements of the forearm (flexion or extension) or by adduction of 

 the arm and retraction of the shoulder combined with outward rota- 

 tion, or by any of these movements of shoulder and arm either com- 

 bined or succeeding one another in definite order, according to the 

 point in the area which is stimulated. Retraction of the shoulder 

 (combined with flexion of the forearm) is alone produced by excita- 



Fig. 1. 



tion of the posterior portion of this area, and when manifested # as the 

 result of excitation applied here, is apt to be associated with move- 

 ments of the trunk, pelvis, or hip, which, as the overlapping of the 

 contours of the areas shows, may also be called forth by excitation of 

 this part. 



In the next area, II, II 7 , we get movements of the trunk muscles as 

 the result of excitation, the chief effect produced being a rotation of 

 the body to the opposite side to that stimulated, combined with an 

 arching of the spine, with the concavity directed towards the opposite 

 side. In the anterior part of the area the chief effect is upon the 

 dorsal region, but in the posterior part it is upon the lumbar region 

 and pelvis. 



