EXPLANATION OF PLATES 



In the diagrams shown on the following plates a uniform arrangement has 

 been followed. The dorsal and lateral aspects of the brains are represented with 

 internal structures projected as dotted lines on the surface. The extent of the 

 lesions is represented by the blackened areas. The numeral on the left is the serial 

 number of the animal, corresponding to the data given in tables 2, 3, and 4, 

 The figures on the right give the percentage of the neopallium destroyed by the 

 operation. 



Figures 1 to 48, inclusive (pis. 1, 2, 3, and 4). Cases in group I, trained after 

 operation, arranged in order of the magnitude of the lesions. 



Figure 49 (pi. 4). Case with thalamic lesion trained after operation. 



Figures 50 to 98, inclusive (pis. 4, 5, 6, 7, and 8). Cases in group B trained 

 before operation, with retention tested after seven days. Arranged in the order 

 of magnitude of the lesions. 



Figures 99 to 102, inclusive (pi. 8). Cases trained before operation. Eeten- 

 tion tested after thalamic lesions. 



Figures 103 to 112, inclusive (pi. 8). Cases in group C trained before opera- 

 tion, with retention tested after fourteen days. 



50 



