336 



PLATE XXIII. 

 FIGURE 1. 



Type of fibre arrangement in the frontal area. 



From a section of the middle frontal gyrus, half way between the sulcus preceutralis inferior 

 and the orbital margin. 



Z = zonal layer. S = supraradiary layer. B = line of Baillarger. R = radiary zone. 



On comparing this with Plate XXL, figure 1 (intermediate precentral), the reduction in fibre 

 wealth will be manifest. 



The right-hand figures and brackets refer to cell layers. : ^. 



FIGURE 2. 



Type of fibre arrangement in the prefrontal area. 



From a vertical sagittal section through the orbital margin of the frontal lobe, '2 cm. from 

 the inner surface. 



Z = zonal layer. S = supraradiary layer. B = line of Baillarger. R = radiary zone. 

 Notice the poverty of fibres on comparison with any other drawing in the whole series. 

 The right-hand figures and brackets refer to cell-lamination, x -," 



