422 J. B. JOHNSTON 
Farther laterally the layer is more compact and the pyramidal 
form of the cells less evident. 
The lateral border of the pallium presents marked characteris- 
tics in the rostral half of the hemisphere. In transverse sections 
the cell layer has a curve near the lateral border which is slight 
in the caudal part of the hemisphere (fig. 15), becomes more 
marked rostrally (fig. 17), and near the rostral end is strongly 
S-shaped (figs. 18, 19). This, together with the slightly larger 
size of the cells and their arrangement in a very compact layer, 
suggests rapid growth and mechanical crumpling of the cell 
layer. This is the border along which internal capsule fibers 
enter and leave the pallium and there is doubtless a difference 
of function between this border and the dorsal or medio-dorsal 
parts of the general pallium. This lateral border becomes 
gradually thicker as it is followed rostrad and dips down and 
becomes more and more overlapped by the pyriform lobe. Here 
the compact plate of cells becomes a thicker mass which in some 
sections is broken into several masses (figs. 23, 24). At the 
rostral end this thickened lateral border produces the pallial 
thickening mentioned in an earlier section. 
Toward the rostral end of the pallium the cell layer becomes 
much less compact except in the lateral thickened border. The 
pyramidal cells with prominent apical dendrites are mostly con- 
fined to the deep layer and outside of these are many cells of 
stellate or ovoid form. These cells are present in the whole 
width of the pallium including the subiculum and the lateral 
thickening. In some sections these cells seem to constitute an 
incompletely separate layer. When the pallial thickening begins 
to form a ridge projecting into the ventricle it is noticed that 
these cells are more numerous in this part of the pallium than 
elsewhere (figs. 21, 22) and from this point on rostrad they form 
a conspicuous outer layer of cells in the pallial thickening (figs. 28, 
24, 25, 40). 
Near its rostral end the total number of cells in the pallium is 
greatly increased, the deep layer is much thickened and very 
dense and the outer layer extends well toward the medial border. 
Indeed, nearly the whole width of the pallium at its rostral end 
