BRAINS OF RATS AND MEN 



23, and 24 illustrate in a diagrammatic way the 

 arrangement of the cells in these fields. 





12 



Fig. II. — Cerebral cortex of the turtle to illustrate the arrangement 

 of cortical cells, magnified 50 diameters. After Johnston (191 5). The 

 region pictured is shown in Fig. 23 and includes the dorsal part of the 

 hippocampal cortex (h) and the transition (sulf.) to the general cortex 

 (g.p.). The ventricular surface is at the right, where it is evident that 

 the amount of white matter between the cortical cells and the ventricle 

 is very thin. It is much thicker in all mammals. 



Fig. 12. — Arrangement of cells in the extreme anterior end of the 

 hippocampal cortex of the opossum at the same magnification as Fig. 11. 

 At the right there is a massive layer of white matter between these cells 

 and the ventricle. 



