518 WILLIAM H. F. ADDISON 
typical fornix fashion to the infundibular region, probably end- 
ing as usual in the nuclei of the corpora mamillaria. 
The corpora mamillaria are very slightly developed, and do 
not show as typical rounded protuberances. However, immedi- 
ately caudad of the posterior wall of the infundibulum is a median 
fissure (fig. 7, section 125), separating gray substance on either 
side which may be taken to represent the position of the two 
corpora mamillaria. In the series studied, there were practi- 
cally no medullated fibers detected in these gray masses, but as 
the fornix fibers penetrate here, there must be some medullated 
fibers present. 
Fig. 15 Diagram of course of fornix fibers, reconstructed from several con- 
secutive sagittal sections (after drawing sent by Professor Edinger). 
IT, optic nerve; c.a., commissura anterior; c.s., corpus striatum; corp.call., 
corpus callosum; for., fornix.; psalt., psalterium; thal., thalamus. 
The taenia thalami or stria medullaris thalami is present as 
a very thin flat bundle lying in the usual position at the mesial 
ridge of the thalamus opticus (fig. 14, section 186). Followed 
anteriorly it becomes thinner and thinner, and cannot definitely 
be traced to the region where it begins, viz., in the parolfactory 
and olfactory cortex. Followed posteriorly towards the gan- 
glion habenulae the number of fibers apparently increases, being 
augmented probably by fibers orginating in the stratum zonale 
thalami. It is quite possible that the olfactory and parolfactory 
portions are entirely absent. 
