152 



Mr. G. A. Watson. 



[July 28, 



to the difficulty experienced in accurately separating the fourth and fifth 

 layers (which tend to intermingle) in the cortex of some animals, the writer 

 prefers to speak of these layers together as infra-granular. It is also 

 proposed for the sake of definiteness to term the true pyramidal layer (i.e., 

 Layer II) the supra-granular layer. 



Areas in the Neopallium. 



The appearances of the cortex in the Mole and Shrew being very similar, 

 the following, concerning the cortex of the Mole, may he taken as applying 

 also to the Shrew excepting when the latter is specially mentioned : — 



1. Dorso-lateral Surface. — In the Mole this region presents two main and 

 distinct types of cortical structure, with certain areas of comparatively 

 undifferentiated cortex (fig. 1). 



Fig. 1.— Dorso-lateral view of the Right Hemisphere of the Mole. 



Left-hand figure, x Area 1, " Motor " ; ii the same, but less characteristic ; Area 2 T 

 General Sensory ; © the same, but less characteristic ; fH Archipallium. 



The anterior, lateral, and posterior areas of undifferentiated cortex are left blank 

 excepting the portion of neopallium represented as shaded, which is thinner than 

 the remainder. 



Right-hand figure, a, rhinal fissure ; b, c, and d, probable representatives respectively 

 of the corono-lateral, supra sylvian, and presylvian sulci ; b, c, and d, vary much in 

 individual distinctness in different hemispheres. The figure is a composite one. 



Area I: Motor. — This extends antero-posteriorly from a short distance 



