6 JOURNAL OF COMPARATIVE NEUROLOGY. 
Temporo-Sphenotdal Lobe. 
This lobe is very highly developed in Macacus. Its ex- 
ternal surface presents the parallel fissure which is the most 
extensive sulcus of the cerebrum. It starts near the apex of 
the temporal lobe, and extends almost to the great longitudinal 
fissure; and there it joins the parieto-occipital fissure. Inferi- 
orly it curves slightly forward; while superiorly it curves 
slightly backwards. The parallel fissure divides the temporal 
lobe into an upper and a lower gyrus. The lower gyrus is 
continued on to the base of the lobe. The superior convolu- 
tion lies below the supramarginal gyrus. It is bounded anteri- 
orly and above by the Sylvian fissure, and posteriorly and be- 
low by the parallel fissure. The base of the temporo-sphen- 
oidal lobe is divided into two convolutions by the collateral 
fissure. This sulcus runs almost parallel with the inferior mar- 
gin of the temporal lobe. It extends from within a short dis- 
tance of the posterior temporal pole almost to the apex of the 
lobe. The collateral fissure forms the lower boundary of the 
hippocampal gyrus. 
The Occtpital Lobe. 
As in man, the occipital lobe of Macacus presents an 
external, an internal and a basal surface. Externally with the 
exception of the superior occipital sulcus the occipital lobe is 
entirely smooth. The superior occipital fissure runs at right 
angles to the external occipital fissure. Externally the occi- 
pital lobe is separated from: the parietal by the par-occipital 
fissure. The inferior occipital fissure separates the occipital 
from the temporal lobe. The mesial surface of the occipital 
lobe presents the cuneus, bounded in front by the parieto- © 
occipital fissure and behind by the calcarine. 
The Limbic Lobe. 
The limbic lobe is bounded above by the calloso-marginal. 
fissure, posteriorly by the rudimentary post-limbic sulcus, 
and inferiorly by the collateral fissure. This lobe includes the 
hippocampal and the fornicate gyri. The gyrus fornicatus 
