1869. | ANATOMY OF PROTELES. 479 
backwards at a right angle, and then descends to the temporal lobe, 
its posterior limb being twice the breadth of the anterior, and in- 
dented by a vertical fissure parallel to the Sylvian. 
The second, or middle gyrus (mm), surrounds the last in the 
whole of its extent, commencing in the frontal and ending in the 
hinder part of the temporal lobe. At its posterior superior angle it 
is partly interrupted in front by a short suleus, which runs upwards 
and backwards from the posterior part of the main sulcus separating 
the inferior from the middle gyrus. 
The third, or superior gyrus (s s) may be considered to commence 
in the supraorbital region*, whence it extends along the upper part 
of the hemisphere, bordered within by the great longitudinal fissure, 
as far as its posterior extremity. Anteriorly it is broad, and is sharply 
folded on itself in a sigmoid manner,—first winding round the supra- 
orbital sulcus (OQ), and then round the crucial suleus (C), which runs 
almost directly outwards from the great longitudinal fissure for the 
distance of half an inch, very near the anterior end of the hemisphere. 
On the inner surface of the hemisphere (fig. 4) the superior gyrus 
is seen to extend completely round the border, bounded below by 
the calloso-marginal sulcus, and interrupted near the front by the 
crucial sulcus. It terminates by joining the middle external sulcus 
at the posterior apex of the hemisphere. It has several indentations 
on its surface, notably a longitndinal one near its hinder end. 
On the inner surface of the hemisphere, below the calloso-marginal 
sulcus, is the “internal” gyrus of Leuret (fig. 4, 2A), which sur- 
rounds the corpus callosum, and may be traced backwards and down- 
wards, around the great opening through which the crus passes into 
the hemisphere to fourm the great prominence of the temporal lobe. 
As the sulcus on the concave side of the lower part of this gyrus forms 
the hippocampus major, it may be called the hippocampal gyrus. 
There are thus four distinct gyri—an inferior, middle, and supe- 
rior external, and an internal or hippocampal gyrus. 
I am not aware of any published description or figure of the brain 
of Hyena; but a specimen is preserved in the Museum of the Royal 
College of Surgeons, the species, unfortunately, not recorded. This 
brain has the gyri and sulci of the cerebral hemisphere arranged on 
exactly the same plan as those of Proteles ; but being a larger brain, 
the secondary sulci are rather more marked. The whole brain is 
rounder in form, both breadth and height being greater propor- 
tionally to length than in Proteles, and consequently the three ex- 
ternal gyri make higher and shorter arches. 
The cerebral convolutions of the Felide are also arranged on the 
same pattern, but are rather more complext. On the other hand, 
* Leuret determines this portion of the brain-surface as a distinct (supra- 
orbital) gyrus. 
+ The uniform character of the cerebral conyolutions in various species of 
Felide was pointed out by Owen (“On the Anatomy of the Cheetah,” T. Z. 8. 
vol. i. p. 133). Much valuable information and some excellent figures of the 
brains of the Carnivora are contained in Leuret’s ‘Anat. Comp. du Systéme 
Nerveux,’ vol. i. 
