FOREBRAIN MORPHOLOGY 407 
tered cells, remnants of the outer general pallial layer connecting 
the pyriform with the hippocampal lobe. 
The hippocampal rudiment (h.c.) consists of a rather dense 
cell-mass, including the above-mentioned ventricular mass of 
emigrating cells, and a lamella of scattered cells lying medial to 
it, continuous with the scattered cells on the surface of the brain. 
D. Cross-section 604 before the foramen monroi (fig. 14). 
The section touches the front surface of the olfactory bulb recess 
and passes through the basal portion of the neuroporic process. 
In the pallial parts the following changes from the preceding ~ 
section are to be mentioned. 
1. The pyriform lobe is, of course, distinct, but its medial 
border is confluent with the lateral part of the general pallial 
cortex. — 
2. The general pallial cortex has grown thicker in its medial 
part than in its lateral, so as to form in the cross-section a club- 
like figure, with the thickening (g.p.t.) directed toward the medial 
line. The medial part of this cortex is bent down a little. 
3. At the point where the pallial thickening just mentioned 
ends we meet with a new cell-mass, emerged from the medial 
emigration (h.em.) locus of the ventricular wall mentioned above. 
From this point there are streaming in, in the dorsomedial direc- 
tion, a dense mass of cells. These cell-groups cover the flanks of 
the neuroporic recess. 
4. The hippocampal formation, lying in the preceding section 
on each side of the neuroporic recess, now forms a bridge above 
the recess, connecting the two hemispheres with each other. The 
emigrating cell-groups (h.em.) of the preceding paragraph seem to 
force this bridge in the dorsal direction and to press it together 
to a relatively thin cell-lamella in the median line. The lamella, 
together with the emigrating cell-masses, representing a second 
emigration of hippocampal cell elements, I consider as the hippo- 
campal formation. 
5. The zonae limitantes are not very conspicuous. 
6. The changes in the subpallial parts are not great. The 
septal nucleus shows two condensations of cells, a dorsal just 
below the neuroporic recess and a ventral a little above the medial 
