OLFACTORY CENTERS IN TELEOSTS PA | 
cus medialis of Kappers, who failed to note the bundle from the 
nucleus posterior tuberis. 
A short distance caudal to the anterior commissure, the medial 
forebrain bundle has increased largely insize (figs. 68, 69), dueto the 
presence of a large number of short fibers, most of which are 
unmedullated. These are present throughout most of the extent 
of tract and are both ascending and descending, connecting and 
placing in relation the different parts of the precommissural 
body, nucleus preopticus and diencephalon. ‘These fibers form 
the tractus olfacto-thalamicus, pars intermedia and tractus thal- 
amo-olfactorius, pars intermedia (fig. 136). 
Another factor in the increase in size of the median bundle 
consists in the addition to it of a few medullated fibers arising 
from the dorso-lateral part of the nucleus magnocellularis, form- 
ing the tractus preoptico-tuberis. These pass caudad mingled 
with the median forebrain bundle and end, apparently, partly 
in the nucleus posthabenularis, and partly in the nucleus posterior 
tuberis. These fibers may correspond to the ‘Liangsbiindel’ 
of Goldstein. 
Slightly caudal to the level of the habenulae a seventh tract 
becomes closely associated with the median bundle, appearing to 
be a part of it. This is the tractus habenulo-diencephalicus of 
Goldstein and has already been described in connection with the 
habenular tracts (fig. 77). 
When a careful study of the median bundle at different trans- 
section levels is made, it is a simple matter to identify its com- 
ponents. Their relations rostrally have already been noted; as 
the tract is followed caudad it will be seen that there is a tendency 
for the longer components to arrange themselves in more compact 
bundles, with the more recently acquired fibers scattered about 
them (figs. 73, 74, 76). For some distance there is little change in 
the bundle (figs. 79, 80, 82). At the level shown in fig. 83, how- 
ever, it will be noted that the fibers of the tractus olfacto-thalami- 
cus, pars intermedia and tractus thalamo-olfactorius, pars inter- 
media, are decreasing in number. The remaining bundles of the 
complex are, at this point, separating from one another, all, how- 
ever, turning ventrad (figs. 100, 101). The tractus habenulo- 
