408 Proceedings of the Koyal Society of Edinburgh. [Sess. 
On the mesial surface (fig. 2) four of the five types of cortex appear, 
and, in addition, extending round the upper border of the corpus callosum 
is the limbic lobe. The upper boundary of this lobe has only been 
Fig. 6.— Type IV. x 100. 
1 
o 
3 
4 
5 
recognised microscopically, as examination of several cerebri has failed 
to identify a definite fissure corresponding to the calloso-marginal. The 
cortex cannot be divided into layers, and is composed of granular and 
polymorphic cells. The larger cells lie in the deepest parts of the cortex, 
