vi] Distribution of the Types of Cortex 157 



The internal layer of large pyramidal cells is again poorly represented, but when we 

 come to the fusiform layer we find not only that the cells are less numerous but their 

 columnar arrangement is perfect. 



It must be admitted that the differences in cell lamination between these two parts 

 are not so great as the differences in fibre-arrangement would lead one to expect, and the 

 only point to which I am inclined to attach real significance is that concerning the giant 

 cells. 



OTHER PARTS OF THE TEMPORAL LOBE. TYPE No. 3 (Plate XVI, fig. 1). 



The remaining part of the temporal field shows the following lamination which, like 

 the fibre-arrangement, is uniformly distributed over the whole of the area represented by 

 small dots in diagram 15. 



Compared with the other areas there is a pronounced diminution in the wealth of cells 

 in all layers, but this is not associated with a reduction in depth. 



Of special importance is the point that no " giant " cells are discoverable, and although 

 the external layer of large pyramidal cells is well-defined, the individual members are 

 uniformly smaller than corresponding cells in the first temporal gyrus and they are also more 

 pyriform ; they average 40 x 20 fj. in diameter, and a feature which drawings show is that 

 they are all more or less equal in size and not mixed up with small cells. 



The layer of stellate cells is again a good one, although perhaps not so prominent as 

 in the special areas above-mentioned. 



A distinct internal layer of large pyramidal cells is now found immediately below the 

 stellate layer; the individual cells measure only 17 x 30 /A and are pale-stained and less 

 numerous than in the external layer. 



Cells in the fusiform layer are relatively scanty. 



DISTRIBUTION OF THE THREE TEMPORAL TYPES OF CORTEX. (Text-figure 15.) 



Type I. Taking the concealed area first, we see, as I have already indicated, that this 

 is confined in a remarkable manner to the transverse temporal gyri or gyri of Heschl ; in 

 the anterior direction the dense fibre-formation is sharply and definitely limited by the line 

 of junction between the most anterior of Heschl's gyri and the relatively flat and deeper- 

 lying surface of the insula proper. 



In the lateral direction it shows signs of coming to the surface at the point where 

 the anterior gyrus of Heschl springs from the superior or first temporal gyrus, and behind 

 this the Sylvian lip of the posterior half of the first temporal gyrus may be regarded as 

 a boundary. While in some brains the coarse fibre-arrangement is completely concealed, in 

 others it is found peeping over the lip of the fissure on to the free surface of the first 

 temporal convolution. 



Posteriorly the area is again submerged and the special fibre-arrangement is only found 

 on the walls of the hinder, forked extremity of the fissure of Sylvius. 



