GROWTH OF THE CEREBRAL CORTEX 143 
pyramids. The density of the polymorphous cells in this sub- 
layer is greatest at the earlier ages. During the early ages the 
most densely crowded pyramids are in the lamina pyramidalis, 
while by contrast the lamina multiformis seems rather poor in 
cells. But in adults the cell population of the ectal sublayer of 
the lamina multiformis appears to be only slightly less than that 
of the lamina pyramidalis and the size of the polymorphous cells 
appears nearly equal to that of the pyramids, though, by an 
exact measurement, they prove to be slightly larger (fig. 6). 
The shape of polymorphous cells is not uniform and they show 
many dendritic processes, irregularly arranged. Some, though 
pyramidal, lie obliquely or transversely, while some hold a re- 
versed position, with the apical dendrite directed entally (Marti- 
notti’s cells). 
The cells of the ental sublayer of the lamina multiformis are 
quite different in their appearance. They are polygonal or 
spindle-shaped and generally lie with their long axis in the plane 
of the lamina. The cytoplasm of the cells is massive and takes 
the stain well. The Nissl bodies, however, are not well dif- 
ferentiated. Though not always pyramidal in shape, the as- 
sumed apex of the cells appears to be directed towards the oc- 
cipital pole in the sagittal and the horizontal sections or towards 
the ventral surface in the frontal section, thus indicating the 
direction of the migration of the nerve cells from the matrix 
to the cortex proper. As already stated by me (Sugita, ’17a), 
this sublayer probably serves as a secondary station for cells 
migrating from the matrix at the ventricular wall to their final 
destination in the cortex and the number of cells in this sub- 
layer diminishes as the age of the brain advances. So one has 
some reason to think that a fraction of the cells found in this 
sublayer are still in transit, at least during the early ages. It 
should be noted at least that the cells of this sublayer have a 
morphology in respect of the mass and the staining reaction of 
their cytoplasm which indicates the stage of migration. 
The neuroglia nuclei are abundantly scattered in the ental 
cortical layers (that is, in the lamina multiformis and the lamina 
ganglionaris) as compared with the ectal layers (that is, in the 
