THE AMYDGALA IN AMPHIBIA 227 
2. An amygdalo-habenular connection by way of the stria 
medullaris, some of these fibers decussating in the anterior 
commissure. 
3. An amygdalo-pyriform connection with the overlying 
pyriform lobe. 
4. The diagonal band of Broca, directed forward and medial- 
ward under the lateral forebrain bundle to connect with the 
septum. 
5. The stria terminalis, directed forward and medialward above 
the lateral forebrain bundle, to connect with the septum and 
preoptic nucleus, some of its fibers probably decussating in the 
anterior commissure. 
6. The ventral olfactory projection tract, directed backward 
and medialward under the lateral forebrain bundle. 
7. The dorsal olfactory projection tract, directed backward 
and medialward above the lateral forebrain bundle, to connect 
with the hypothalamus. 
These seven connections will next be described. They are 
schematically indicated in figures 35 and 36. 
The commissura amygdalarum. This is a very small compact 
strand of unmyelinated fibers passing between the two amygdalae 
in the anterior commissure (figs. 17, 20). It lies ventrally of the 
decussations of the amygdalo-habenular tracts and lateral fore- 
brain bundles and dorsally of that of the medial forebrain bundle. 
In Golgi preparations its fibers are lost in the dense neuropil of 
the amygdala and their cells of origin are not demonstrated. 
Tractus amygdalo-habenularis. This is a system of fibers, partly 
myelinated (figs. 6, 7) and partly unmyelinated (figs. 17, 18), 
between the amygdala and the habenula. They accumulate 
on the dorsomedial border of the amygdala and pass directly 
dorsalward to enter the stria medullaris. Some of them appear to 
decussate in the anterior commissure dorsally of the commis- 
sure of the amygdalae and decussation of the lateral forebrain 
bundles and ventrally of the hippocampal commissure (fig. 17, 
d. amg. hab.). This component of the anterior commissure is 
of open texture and its fibers are diffusely arranged, in marked 
contrast with the other three components of this commissure 
complex last mentioned. 
