242 Cc. JUDSON HERRICK 
Unmyelinated fibers from all parts of the olfactory bulb also 
pass backward in diffuse formation into the ventrolateral part 
of the hemisphere. These come from both the anterior and 
posterior parts of the olfactory bulb and pass caudad, partly 
mingled with but chiefly superficially of the fibers of the lateral 
forebrain bundle (fig. 25). 
Here I must correct the account of the ventrolateral olfactory 
tract given in my previous description of the brain of Ambly- 
stoma (10, p. 422), which was based on material inadequate 
for accurate study of the unmyelinated fibers. This tract does 
not arise exclusively from the accessory bulb and pass “directly 
back close to the ventricular ependyma to end in a cellular thick- 
ening at the caudal end of the pars ventro-lateralis opposite 
the anterior commissure,’’ as in the frog. There is no such 
specific relation to the accessory bulb or to the amygdala here. 
Bindewald (14, p. 39) very correctly failed to confirm my descrip- 
tion. The ventrolateral tract occurs, but not as I formerly 
described it. 
Clearly the accessory olfactory bulb is by no means so specific, 
a structure asin the Anura. It is not so well separated anatomi- 
cally from the rostral part of the bulb and. the ventrolateral 
olfactory tract arises from both of these parts of the bulb and 
not exclusively from the accessory bulb, as in the frog. This 
ventrolateral tract, accordingly, is not the exact equivalent of 
the tract so named in the frog, though the latter is derived from it 
by the suppression of the fibers from the olfactory formation and 
further specialization of those from the vomeronasal formation. 
The ventrolateral area of the cerebral hemisphere 
The forebrain of Amblystoma has been several times described, 
the most important papers being those of Stieda (75), Herrick 
(10), and Bindewald (14). Figures showing the general struc- 
ture will be found in the two papers last cited. 
The structure of the urodele cerebral hemisphere is much more 
generalized than that of the Anura, though the more important 
anuran regions can be recognized. The olfactory bulb makes 
up the entire lateral wall in front and part of it for a considerable 
