408 NILS HOLMGREN 
border of the tuberculum olfactorium cortex. Between the two 
ventral nuclei the space is filled up by scattered cells. 
7. he bulbar nuclei are confined to the bulbar rudiment. The 
nucleus olfactorius lateralis is a rather dense cell-mass filling 
up the space between the bulbar rudiment and the tuberculum 
olfactorium cortex. 
i. Cross-section through the frontal part of the foramen 
monroi (fig. 15). 
In the pallial parts the most striking feature is that the hippo- 
campal formation forms an unpaired medial cell-mass (h.c.) 
and that the thickened medial part (g.p.t.) of the general pallium 
cortex (g.p.c.) extends medially to form a little more caudally a 
continuous layer above the hippocampal formation which at the same 
time decreases to form more caudally a very low cellular ven- 
tricular eminence. The cells of the thickened general pallial 
cortex are not so densely crowded as those of the remainder of 
the same cortex. Laterally this cortex is confluent with the pyri- 
form cortex (p.c.). The zona limitans lateralis (z.1.1.) is well 
pronounced. 
In the subpallial parts the ventral septal nucleus mentioned 
sub C, 6 is found in the medial line between the two cortical 
layers of the tubercula olfactoria as an unpaired thick ventricular 
layer of relatively scattered cells. The scattered cells in C, 6 
lying between the two nuclei, are found ventral to this unpaired 
nucleus. 
I’. Cross-section through the hind part of the forebrain, 
where the latero-occipital ventricles are disappearing (fig. 16). 
In this section the dorsal continuity of the general pallia is 
broken. The thickened part of the cortex (g.p.t.) has grown 
very greatly and becomes caudally larger and larger so as to 
fill up the whole dorsal part of the connecting lobe of the telen- 
cephalon. The pyriform cortex (p.c.) medially is continuous with 
the general pallial cortex (g.p.c.). Laterally it is not well marked 
from the lateral olfactory nucleus (n.olf.l.).. Thus a zona limitans 
lateralis is not to be found in this part of the brain. 
The subpallial part has not greatly changed its appearance 
from the foregoing section. The medial parts of the tuberculum 
