THE AMYGDALA IN AMPHIBIA 245 
The dense neuropil of the ventrolateral nucleus is composed 
chiefly of terminals and collaterals of fibers of the lateral fore- 
brain bundle (fig. 28). These are both ascending and descending 
fibers. Within it are found also the fibers of the dorsal olfactory 
projection tract, as described below. Myelinated fibers (crossed 
and direct) connect this neuropil with the habenula in the same 
way as similar fibers in the frog are related to the amygdala 
H. 2t14-3- 1-2 
Fig. 25 Horizontal section through the brain of adult Amblystoma tigrinum 
at the level of the interventricular foramen. «Golgimethod. X 12. Thesec- 
tion illustrates the origin of the ventrolateral olfactory tract from all parts of the 
olfactory bulb; also the course of the more dorsal fibers of the lateral forebrain 
bundle and the mingling of these fibers with those of the olfactory tract, in 
marked contrast with the condition in the Anura, figures 19 and 20. 
(tractus amygdalo-habenularis). These are the fibers termed 
tractus habenulo-striaticus in my earlier paper (’10, figs. 16, 17, 
18, tr. hab. st.). A large fascicle of the anterior commissure 
containing both myelinated and unmyelinated fibers connects 
the two ventrolateral nuclei (figs. 24, 28, and Herrick, ’10, fig. 16, 
c. a. lat.). These include decussating fibers of the lateral fore- 
brain bundles and probably also representatives of the several 
systems found in the frog connecting the two amygdalae. 
