THE AMYGDALA IN AMPHIBIA LA DAFAI| 
relations as in the rabbit (Winkler and Potter, ’11). In Weigert 
sections it appears to receive fibers from the overlying lateral 
olfactory tract. It gives rise to a fascicle of myelinated fibers 
of small size which enters the stria terminalis and can be followed 
separately for the entire length of the stria. They form the 
most ventral fibers in the dorsal loop of the stria, and many of 
them can be followed into the anterior commissure. These 
relations are confirmed in sections stained by Cajal’s method. 
Stria terminalis fibers are related to the entire extent of the amyg- 
daloid complex and the overlying cortex of the pyriform lobe. 
Some fibers associated with these can be definitely followed into 
the habenula, but I have not demonstrated that any of these 
arise specifically from the area presubicularis. 
So far as present information justifies conclusions, it may be 
suggested that the structure here designated amygdala in the 
Anura is represented in mammals by the presubicular area and 
the adjacent region termed subiculum cornu Ammonis by Winkler 
and Potter (’11, fig. xi) and the paleostriatal element of the 
amygdaloid complex by Dart (’20), though the homology probably 
is not exact. The remainder of this complex in the Amniota does 
not seem to be so closely related with the olfactory system and is 
not represented as a differentiated structure in the frog. 
That the olfactory component is not essential to the integrity 
of the mammalian amygdala is clear from the fact that in the 
totally anosmic dolphin the amygdaloid complex is of large size, 
in marked contrast with the atrophied pyriform lobe and hippo- 
campus (Zuckerkandl, ’87, p. 113; Addison, 715). The fact that 
in the dolphin the stria terminalis, though present, is very small 
(Addison, ’15) supports the view that this tract is to be regarded 
as largely composed in mammals of descending olfactory pro- 
jection fibers. 
The relation of the amygdala to the pyriform lobe requires a 
further comment. Ihave earlier (’10, pp. 479, 487) compared the 
dorsolateral quadrant of the amphibian cerebral hemisphere with 
the mammalian pyriform lobe, stating, ‘‘it is represented in mam- 
mals as one of the components of the pyriform lobe,” and ‘‘the 
function of the amphibian dorso-lateral part, as of the pyriform 
