1581 
We may therefore say, that with all semnopitheci and related 
monkeys, which have on the posterior pole only one large, well- 
developed cross-suleus (the mm + m’ suleus) this place is predisposed 
to form the ape-fissure. 
However from this cannot be concluded that under all circumstances, 
exactly the same part of the brain surface will be pushed downwards. 
On the contrary, we shall directly see, that important differences occur. 
For instance, if we look at fig. 11. The / + e + mm + m’ sulei 
are drawn. The front and hindlip are visible. The frontlip belongs 
to the parietal lobe, the hindlip to the occipital lobe. More caudally 
front face 
furrow, tiie later 
fis. simialis. 
dccip. pool 
Fig. 11. 
voorlip = front lip, achterlip = hind lip, 
pool = pole 
the occipital pole appears. Suppose we take the centre of the greatest 
growth lying far back, to say near --. 
If this hind part enlarges greatly, then there will appear just in 
front of it a furrow, the later fissura simialis, e.g. on the level of 
the dotted line. 
All that is lying in front will be placed on the anterior surface 
of the ape fissure. All that is lying 
behind it, will be found onits posterior 
surface. 
This aspect is demonstrated, accord- 
ing to the description of most of the 
investigators, in the largest number 
of cases e. g.: ZUCKERKANDL. 
If one severs the hind surface 
(the operculum) of the ape-fissure, 
indeed the caudal part of / He (s. 
interparietalis) and 7 + m’ (fig. 12) 
ZUCKERKANDL. appear on the front surface. 
Fig. 12. One sees therefore that what I 
