42 
BULI,ETIN OF THE LABORATORIES 
In front of the corpora quadrigemina is a strong posterior commissure. 
The lower portion of the third ventricle pertaining to the tuber cin- 
erum is bounded behind by the tuberculum mamillare and the substan- 
tia cinerea posteriora, in front by the thin grey lamella rising to the cor- 
pus striatum, the lamina iemninalis. 
The copora striata are pear shaped bodies, the anterior portions of 
which are connected by the septum pellucidum,, which, in turn, is con- 
nected with the lamina terminalis. The septum is perforated by the 
fibres of the commissure anterior. The lower surface of each hemi- 
sphere is provided with a protuberance or pyriformis (in reali- 
ty produced by the fold of the hippocampus) which is separated by a 
sulcus {rhinaiis and post-rhinalis) from the remainder of the cortex. 
From the anterior or narrow portion of this pear shaped area extends 
the olfactory lobe. 
Removal of successive horizontal slices of the hemispheres exposes 
the callosum^ which is medianly connected by a considerable adhesion 
with the cornua ammo Ji is. Each lateral ventricle is a cavity lying 
between the corpus striatum and septum pellucidum in front and be- 
tween the corpus striatum and cornu ammonis below and medianly. 
After suitable preparation, fibres can be seen crossing below the callos- 
um and ending in the groove between the thalamus and striatum and 
probably representing the posterior limb of the fornix. 
Cranial Nerves I and II, as usual. The oculomotor (III) springs 
from the median surface of the crura, just behind the corpus mamillare. 
The trochlear is (IV) originates as a fine fibre from the horizontal part 
of the valvLila cereb^lli, immediately behind the quadrigemina. • The 
trioe/ni.nu^ (V) arises just posterior to the pons and is cmnposed.of a 
lateral portio major and median portio minor. The abducens (VI) 
emerges near the median line, near the posterior margin of the pons. 
The facial (VII) emerges obliquely from the medulla behind the pons 
upon the corpus trapezoideum. The auditory (VIII) springs from the 
lateral surface of the tuberculum laterale, immediately behind the tri- 
geminus. The glossopharyngeal (IX) is a root of about three bundles 
springing from the lateral surface of the medulla behind the tubercu- 
lum laterale, forming a small ganglion. The vagus (X) consists of 
several bundles, forming an arch along the lateral surface of the me- 
dulla, the lowest bundle being continuous with the accessory (XI), fibres 
of which extend back as far as the third or fourth spinal nerves. The 
