340 



PLATE XXV. 



FIGURE 1 . 



Type of fibre arrangement in the insula. 



From a transverse section through the middle of the gyrus central!* anterior iusulae. 



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

 hand figures and brackets refer to cell layers. 



The poor general supply of fibres suggests functional unimportance. The marked zonal layer 

 is attributable to the truth that the insula is a covered part and comparable with a sulcus. < ~. 



Insula. Type of cell-lamination. Drawing from a section immediately anterior to the sulcus 

 centralis insulae. 



1, plexiform layer. 2, small pyramidal cells. The apparent great depth is due to slight 

 obliquity of the section. 3, medium-sized pyramidal cells. 4, external large pyramidal cells. It 

 may be noted that the majority of these are little larger than the cells in layer 3. 5, the layer 

 of small stellate cells, is indefinite, and its members encroach on adjacent layers. 6, internal 

 large pyramidal cells. The prevailing element is slightly larger than that in layer 4. 7, fusiform 

 cells. 



Notice the difference between this arrangement and that in the transverse temporal gyri. 

 Plate XV., figure 1. 



Magnifications x ? T - and x i|- . 



