SCIENCE. 
327 
fissures and the ascending branches of the calloso- 
marginal, is well defined. The lower parietal lobule in 
the Orang divides naturally into the supra-marginal and 
angular gyri. The supra-marginal fold curves around 
the upper end of the posterior branch of the fissure ot 
Sylvius and runs into the superior temporal gyrus. The 
angular gyrus, which is very evident, arches around the 
first temporal fissure, and becoming continuous with the 
second occipital fold, passes then into the upper temporal 
Fig. 3. 
gyrus. The occipital lobe, separated from the parietal, 
internally, by the parieto-occipital fissure, is continuous 
with the upper parietal lobule through the first occipital 
gyrus, and by the second occipital gyrus ^with the 
angular. There are no sharp lines of demarcation be- 
tween the occipital and temporal lobes. In the occipital 
lobe of my Orang the transverse occipital fissure was 
present, and received the parietal fissure. The calcarine 
fissure was well marked, but was separated in the Orang 
from the parieto-occipital fissure by the “ deuxieme plis 
de passage interne ” of Gratiolet, the “ untere innere 
Scheitelbogen-Windung ”of Bischoff. The cuneus of the 
Orang is therefore some w hat different from that of man. In 
man I have seen these two fissures separated as an ano- 
maly. The calcarine passed into the hippocampal fissure, 
so that in the Orang, as in monkeys generally, the gyrus 
fornicatus was separated from the hippocampal gyrus, 
whereas in man these convolutions are continuous. 
This disposition has been noticed in the Hylobates, in 
Ateles, and in one Chimpanzee, where the calcarine did not 
reach the hippocampal. The first occipital gyrus is very 
well developed, and as the late Professor Gratiolet 
observed, is one of the most striking convolutions 
Fig. 4. 
in the brain of the Orang. It rises so to the surface 
that the internal perpendicular fissure or external part 
of the parieto-occipital fissure is almost entirely bridged 
over, the operculum so characteristic of the monkey 
almost disappearing. It is continuous with the upper 
parietal lobule arching around the parieto-occipital 
fissure. This convolution comes to the surface in the 
Hylobates and Ateles almost to the same extent as in 
the Orang, but it is more developed in the latter than in 
the Chimpanzee. It is called also the “ premier plis de 
passage exteme,” by Gratiolet, the “ obere innere 
I Scheitelbogen-Windung,” by Bischoff, the “ first an- 
I nectant gyrus,” by Huxley, and “ first bridging convolu- 
i tion,” by Turner. The second occipital convolution 
connects the occipital lobe with the angular gyrus. In 
my Orang it was partly concealed by the first occipital. 
; It was not as superficial as in man, The third occipital 
gyrus is continuous with that part of the temporal lobe 
. below the first temporal fissure. I noticed, also, in my 
Orang the “ quatrieme plis de passage ” of Gratiolet. 
; On the mesial side of the occipital lobe in my Orang 
■ was well seen the “ deuxieme plis de passage interne ” 
of Gratiolet, the “ untere innere Scheitelbogen-Windung ” 
! of Bischoff, which separates the calcarine from the pari- 
; eto-occipital fissure ; and in both the Orang and Chim- 
' panzee, more especially on the left side, I had no diffi- 
i culty in recognizing the “ premier plis de passage 
j interne ” of Gratiolet, its convexity turning inwards, 
while that of the first occipital gyrus, or the “ premier 
plis de passage externe,” turns outward. These two 
convolutions, the first occipital gyrus and the premier 
plis de passage interne,” in my Orang were continuous. 
They are regarded as one by Bischoff, forming his 
“ obere innere Scheitelbogen-Windung,” but as two by 
Gratiolet, constituting his “ premier plis de passage ex- 
terne et interne.” 
The temporal lobe in the Orang is much less convo- 
luted than in man, or even in the Chimpanzee. The first 
temporal fissure and first temporal convolution are well 
marked, but the second and third are badly defined 
Fig. 5. 
The fusiform and lingual lobes are separated by the in- 
ferior occipito-temporal fissures, the collateral fissures of 
Huxley. The Island of Reil was perfectly covered in 
both the Chimpanzee and the Orang by the operculum, 
but was not convoluted in my Orang. The surface in 
places was slightly roughened. I noticed, however, 
three or four convolutions in the Chimpanzee. On mak- 
: ing a section of the left hemisphere of the Orang I no- 
ticed that the corpus callosum was relatively smaller 
than in man, but that the ventricle exhibited an anterior, 
j middle and posterior cornu, the corpus striatum, taenia 
1 semicircularis, thalamus opticus and fornix were well 
I developed, the hippocampus major with corpus fimbria- 
turn were perfectly evident, and the hippocampus minor 
larger relatively than in man. I did not see a trace of 
the emmenentia collateralis ; this is often, however, ab- 
sent in man. 
The cerebellum in my Orang was relatively larger 
than that of man, but smaller than that of either of the 
! Chimpanzees I have dissected, and was just covered and 
I no more by the posterior lobes of the cerebrum. This 
I relation is still retained in my Orang, though the brain 
has been lying in alcohol for three months since it was 
taken out of the chloride of zinc in which it was placed 
until the pia mater could be removed. During th s peiiod 
it has been subject to the conditions, such as the want of 
the support of the membranes, the effect of pressure, 
etc., urged by Gratiolet, Huxley, Rolleston, Marshall, 
etc., as sufficient to explain why after death the cerebel- 
lum is uncovered by the cerebium in the Orang and 
Chimpanzee, as held by Owen, Schroder van der Kolk 
and Vrolik, and Bischoff. Every anatomist knows that 
