583 
of Edinburgh, Session 1865-66. 
reached the longitudinal fissure of the cerebrum, of which it formed 
the boundary for half an inch, and then joined the inner end of the 
first occipital convolution. A secondary fissure passed for some 
distance into its substance before it joined the occipital lobe. 
Throughout its entire extent it formed a very distinct, superficial, 
first connecting convolution, almost as well marked, indeed, as that 
figured and described by G-ratiolet as so remarkable and distinctive 
a feature of the brain of the Orang amongst the apes. 
On the left side no first connecting convolution existed ; but 
from the superior angle of the bent convolution, where it became 
continuous with the descending limb, a narrow convolution {B, 
fig. 1), |-th of an inch wide, arose. At its origin it was concealed 
by the occipital operculum ; but almost immediately it became 
superficial in the parieto-occipital fissure, passed almost transversely 
inwards, and joined the inner angle of the superior occipital con- 
volution close to the longitudinal fissure. The length of its super- 
ficial portion was f ths of an inch. From its origin it was evidently 
the second bridging convolution, and in its superficial position it 
exhibited an arrangement such as has not before been recognised 
in the brain of the Chimpanzee, and which G-ratiolet, indeed, had 
not met with in any of the numerous brains of the Old World apes 
which he had examined. 
The convolutions of the occipital lobe presented no variation in 
arrangement calling for special remark. They were joined, in the 
usual way, by the third and fourth superficial bridging convolu- 
tions proceeding from the temporo-sphenoidal lobe. 
In the disposition of parts about the Sylvian fissure, the brains 
B and G corresponded closely to those figured by Professors 
G-ratiolet and Marshall, but in the brain A an arrangement prevailed 
such as has not yet been described in the brain of the Chimpanzee. 
The anterior lip of the Sylvian fissure was as usual sharp and well- 
defined, but the posterior marginal convolution (gjli Um'poral 
superieur), instead of forming the posterior boundary of this fissure 
in its entire extent, became gradually narrower as it ascended, and 
at the same time receded from the surface. As a consequence, its 
upper end was entirely concealed, the Sylvian and parallel fissures 
became continuous superficially with each other, and the ascending 
and descending limbs of the bent convolution formed the anterior 
4 G 
VOL. V. 
