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372 ELIZABETH CAROLINE CROSBY 
representatives of that tract in reptiles. It has been termed in 
this account, the ventral olfactory projection tract. 
The portion of this tract which arises from the pyriform lobe 
and associated regions is evidently the same tract as that de- 
scribed by Kappers and Theunissen (’08, p. 225) for the lizard, 
Iguana, under the name tractus olfacto-habenularis (see figures 
21 and 22 of their paper). Farther forward these authors de- 
scribe it as turning lateralward to connect with the ‘lateralen 
Lobusrinde’ (fig. 20), which is apparently the pyriform lobe region 
of the present account. 
There are probably other components of this fiber complex 
which have not been impregnated in the preparations studied. 
3. Tractus cortico-habenularis lateralis posterior (figs. 20, 21). 
This large system of fibers arises from the nucleus of the lateral 
olfactory tract and the ventro-lateral part of the dorso-lateral 
area. Some of its fibers may arise from the overlying cortex of 
the pyriform lobe. These fibers pass medialward, at the same 
time sweeping dorsalward to avoid the area of distribution of 
the stria terminalis. At the lateral border of the thalamus they 
run parallel with and dorsally of the stria terminalis fibers (figs. 
20, 21) and here they turn abruptly dorsalward to enter the 
stria medullaris thalami. 
4. Tractus olfacto-habenularis medialis (figs. 20, 21). This 
tract arises from the more posterior portion of the nucleus pre- 
opticus, runs dorsalward medial to the medial forebrain bundle 
and turns forward and forms the most anterior part of the stria 
medullaris. 
5. Tractus olfacto-habenularis lateralis (figs. 20, 21). This 
tract has its origin from the more anterior portion of the nucleus 
preopticus. It runs first lateralward on the extreme ventral sur- 
face of the brain ventrally of the basal forebrain bundles, then 
backward and dorsalward, joining the tractus cortico-haben- 
ularis lateralis anterior in the angle between the ventro-medial 
nucleus and the lateral forebrain bundle and passes dorsalward 
with it to enter the stria medullaris. (See description of trac- 
tus cortico-habenularis lateralis anterior for a further account 
of the relations.) 
