. 219 
Anatomy. — “The ape fissure — sulcus lunatus — in man’. (By 
Dr. D. J. Hursnorr Por). (Communicated by Prof. C. WINKLER). 
(Communicated in the meeting of May 27, 1916). 
On the appearance of an ape fissure in man, opinion is still 
divided. 
While e.g. KonuLBruoer ') considers himself obliged to accept that 
the latter is only found in apes, Error Smita*) comes to the 
conelnsion that the suleus lunatus, described by him, is nothing 
else but the fissura simialis in apes and that this fissure constantly 
appears (a constant feature of the human brain). " 
It is, superficially seen, quite remarkable, that such a great 
difference in opinion exists «about the appearance or not of such 
an importantly developed fissure. 
The reason of it has to be looked for in the fact, primarily, that 
it is especially difficult to homologise at the occipital pole the sulci 
of apes with those of men, secondarily, because no count has been 
kept with the development of the fissura simialis in embryos of 
primates. 
When one does not carefully examine where and how the fissura 
simialis develops in embryos, it will always remain a fruitless work 
to discuss whether between the manifold sulci and fissures on the 
posterior part of the buman brain one can be found, which could 
be placed on the same level with the fissura-simialis in primates. | 
In my record on the development of this fissure *) and its relation 
to the “plis de passage” *) I explained: 
a. that the ape fissure is a non-constant fissure, 
b. that it is formed in foetal life, after the other sulci are 
already present, 
ce. that it is formed by the same ape species always nearly 
on the same spot, 
d. that it can be formed in different ape species at different places, 
e. that the characteristics, by which it can be recognised from 
the other sulci, in the different ape species, can be totally different. 
If we therefore want to investigate whether in man an ape fissure 
is present, then one has to take with the previous results into account. 
In semnopitheci I pointed out that in first instance the sulci are 
formed on the brain surface and that only afterwards, when a larger 
growth of the occipital part should take place, a curvature appears, 
which is to be taken as the beginning of the fissure. It is now the 
question, whether in man the same relation may be expected. 
