238 Relations of the Frontal Lobe in the Monkey 
the fibers passing mostly outside the claustrum and turning around the 
posterior extremity of the lenticular nucleus. That many of these fibers 
running backward beneath the cortex of the island pass to the temporal 
and occipital lobes is well known and this explains many clinical mani- 
festations. But we appear to have here at least four tracts: 
1. That going to the superior temporal convolution ; 
2. That going to the occipital lobe ; 
3. That just referred to as turning inward around the posterior angle 
of the lenticular nucleus and joining the fibers from the posterior segment 
of the internal capsule on their way to the central gray matter around 
the aqueduct; and 
4. A group of fibers passing inward and downward from the area of 
Wernicke to end in the superior colliculus. 
ABBREVIATIONS USED IN THE FIGURES. 
A. = Aqueduct of Sylvius. 
Aff. S. — Affenspalte. 
A. P.F. = Anterior pillar of the fornix. 
C.A. = Anterior commissure. 
C.C. =Corpus callosum. 
C.L. =Body of Luys. 
C.P. = Posterior commissure. 
E.G. =External geniculate body. 
F.M. =F¥oramen of Monro. 
F.R. = Fasciculus retroflexus of Meynert. 
G. H. =Ganglion habenule. 
Gl. P. = Pineal gland. 
I.G. =Internal geniculate body. 
I. P. =Interparietal sulcus. 
fea Lesion: 
N.A. = Anterior nucleus of the thalamus. 
N.C. =Nucleus caudatus. 
N.M. —Centre median. 
N.R. =Red nucleus. 
N.T. =Trochlear nucieus. 
PP —Pulvinanr: 
P.C.I. =Pre-central sulcus, descending ramus. 
R. =Fissure of Rolando. 
R. III. = Root-bundles of third nerve. 
S. = Fissure of Sylvius. 
S. T. = Temporal sulcus. 
V. = Ventricle. 
V. dad’ A. =Column of Vicq d’ Azyr. 
