262 Cc. JUDSON HERRICK 
therefore retains the primitive characteristic of the lateral olfac- 
tory area. The differentiation within this area is chiefly correla- 
ted with the entrance of various specific non-olfactory systems 
of fibers. 
4, The region bordering the olfactory bulb is least affected 
by these immigrant systems and is termed the nucleus olfactorius 
anterior. 
5. Most of the fibers of the lateral olfactory tract enter the 
dorsolateral area, which is therefore the chief lateral olfactory 
nucleus. 
6. Posteriorly this quadrant receives ascending thalamic fibers 
from the lateral forebrain bundle, ascending hypothalamic 
fibers from the olfactory projection tract, association fibers 
relating it with the adjacent primordial hippocampus (dorso- 
medial area), and commissural fibers from the hippocampal com- 
missure; it discharges the lateral cortico-habenular tract to the 
epithalamus and may also discharge into the hypothalamus. 
These connections define this region as primordial pyriform lobe 
(see beyond, p. 271). 
. 7. The relations of the ventrolateral area to the ascending and 
descending fibers of the lateral forebrain bundle indicate that 
here is to be sought the functional equivalent of the corpus 
striatum (paleostriatum); but since there is no group of neurons 
related with the thalamic and tegmental fiber systems of the 
lateral forebrain bundle which do not also receive secondary 
olfactory fibers (by the ventrolateral olfactory tract), or ascend- 
ing hypothalamic fibers (by the olfactory projection tract), or 
both of these systems, it is clear that in the urodele there is no 
anatomical structure to which the name corpus striatum can 
properly be given. 
- 8. The amygdaloid complex of reptiles (Johnston, ’15; Crosby, 
17) is related to the lateral olfactory tract, the hypothalamic 
olfactory projection tract, the stria medullaris for the habenula, 
the stria terminalis, and the diagonal band of Broca. The first 
three of these fiber tracts (and probably the other two) are related 
with the ventrolateral nucleus of the urodele hemisphere, but 
not with any specific group of neurons within this nucleus. Here 
