370 ELIZABETH CAROLINE CROSBY 
the basal centers of the septum and hypothalamus. In the alli- 
gator there is a broad connection between the medial forebrain 
bundle near its anterior end and the overlying hippocampus 
which is probably in a general way comparable with the mam- 
malian fornix longus. Since these fibers connect chiefly with 
the lateral or ventricular side of the layer of cortical cells, they 
probably are mainly descending projection fibers for the septum 
and hypothalamus. 
Stria medullaris 
The stria medullaris is made up of a number of fiber tracts 
running from secondary and tertiary olfactory centers to the 
habenula. (figs. 11, 20, 21). The terminology here used follows 
Herrick (10). The following components were identified and 
traced out: . 
1. Tractus cortico-habenularis medialis (figs. 18 to 20). This 
tract arises for the most part from the axones of the double 
pyramids and small projection cells of the hippocampus. Its 
fibers leave the hippocampus at the same level as those for the 
columna fornicis and the commissura hippocampi. All three 
bundles run ventralward together, the more lateral belonging 
to the tractus cortico-habenularis medialis, the intermediate 
ones to the columna fornicis, and the medial ones to the commis- 
sura hippocampi. After a time the commissural fibers run more 
toward the mid-line and become separated from the general 
fiber mass, while the cortico-habenular fibers turn dorso-lateral- 
ward, and, passing caudad into the diencephalon, enter the stria 
medullaris. 
Part of the fibers of this medial cortico-habenular tract arise 
among the cells of the nucleus commissurae hippocampi. Scat- 
tered cells of this nucleus accompany the tract through the 
greater part of its course. Accordingly the tractus cortico- 
habenularis medialis receives impulses from the hippocampus 
of the same and the opposite side, impulses coming from the lat- 
ter by way of the commissura hippocampi and its nucleus. 
2. Tractus cortico-habenularis lateralis anterior (figs. 16 to 21). 
The fibers of the anterior division of the lateral cortico-haben- 
