220 
When I do not go back further than nearly half a century, 
Ecker®) laid stress on the fact, that in the 9'* month of foetal life 
all the principal sulci and principal gyri are already formed, but 
that the subsulei and subgyri are still missing for a great part 
(p. 222 sub 14)). If therefore an ape fissure should be formed, then 
this will, being an important suleus, be formed during foetal life. 
Retzivs came just to the same conclusion, who added to it (p. 27), 
that in a sufficient number of specimens out of this foetal period, 
one can find all the varieties, which appear on the brainsurface 
of adult human beings. 
This report therefore also points out that in case an ape fissure 
should be there, it has to be demonstrated in foetal life. 
The above mentioned agrees with what is found in apes, and 
the ape fissure in man therefore will also be best examined on 
foetal brains. Moreover it is of great profit that the complex of 
sulci before birth is not yet as complicated as in the adult state. 
From the embryology, which Ecker gives to us, it appears that the 
development of all the principal sulci can be distinctly followed, 
but that there is not one among them, which leads us to suppose 
it the ape fissure. As the sulci till the beginning of the 9 month 
show a simple type, it is not difficult to come to a similar 
conclusion. 
The only exception could possibly be made by his transitory sulci, 
of which some run transversally on the posterior lobe. These 
however cannot be compared with an ape fissure, because they are 
only of temporary nature and disappear in the 4 and 5‘> months. 
Rerzius too, who neither speaks of an ape fissure in foetal life 
in the embryology, described by him, does not think these transitory 
sulci of great importance. He e.g. points out (p. 16) that in judging 
the value of these sulci one has to be very careful, as a great 
number of the young abortised embryos carry the sign of being 
abnormal, what naturally has to be found back in the brains. 
I believe that Rerzius has given hereby a very important fact for 
the development of these sulci and it is therefore necessary not to 
value highly these transitory sulci. 
On the other hand Rerzius intends to draw especially attention to 
a suleus, which runs from the medial junction of the fissurae parieto- 
occipitalis and calearina on the lateral occipital surface. Plate XX VI, 
fig. 2, 5 and 4. 
If one examines this suleus, which is also drawn on page XXII, 
fig. 2 and plate XIII, fig. 8 and 9. then this shows a great resem- 
blance with an ape fissure. The only thing is, that it is found in 
