THE AMYGDALA IN AMPHIBIA 231 
Here they form a compact sheet of fibers directed ventralward, 
medialward, and forward. Some of them apparently connect 
with the preoptic nucleus; others extend farther forward to 
connect with the septal nuclei (figs. 14 to 17). 
Stria tetminalis. There is another connection of unmyelinated 
fibers between the amygdala and the medial olfactory areas of 
the septum and preoptic nucleus. These fibers leave the medial 
surface of the amygdala near its rostral end and pass medialward 
and forward dorsally and medially of the lateral forebrain bundle, 
forming the stria terminalis (fig. 16). The diagonal band and the 
stria terminalis are best seen in our Cajal sections. The direction 
of conduction is not revealed in these preparations. The fibers 
of both tracts probably run in both directions between the amyg- 
dala and the medial olfactory areas. Some fibers of the stria 
terminalis system probably decussate in the anterior commissure, 
though our preparations do not demonstrate this. 
The ventral olfactory projection tract. These fibers (fig. 18) 
occupy the same position as the diagonal band of Broca farther 
rostrad, these two systems-forming a single sheet of fibers running 
superficially across the prominentia fascicularis and distinguished 
‘only by the fact that the fibers of the diagonal band are directed 
forward, while those of the projection tract are directed ventral- 
ward and probably spinalward. The latter join the medial 
forebrain bundle, and their destination is unknown. They 
probably connect with the adjacent preoptic nucleus and perhaps 
with the hypothalamus. The direction of conduction has not 
been determined. 
The dorsal olfactory projection tract. This small but very well- 
defined tract takes a course similar to the last, except that it 
runs dorsally and medially of the lateral forebrain bundle and 
can definitely be related to a specific nucleus of the hypothalamus. 
Almost the entire course of this tract can be seen in a single 
section in some of our Golgi preparations, as illustrated in hori- 
zontal section of Acris gryllus in figure 20 and in an oblique 
plane in Rana pipiens in figures 22 and 23. For the relations 
in transverse sections see figures 6 to 12. Its fibers take a very 
direct course between the amygdala and the gray matter near 
