Physiology. — “On Cyclopia with conservation of the Rhinen- 
cephalon”. By Prof. C. Winker. 
(Communicated in the meeting of May 31, 1919). 
In These Proceedings of February 1916 I reported the results 
found after examination of the brains of three cyclopian monstra. 
I then pointed out, that the characteristic abnormality in all these 
brains, was the presence of a sack with a thin wall, formed by the 
roof of the third ventricle, largely extended by fluid. 
1 was forced to contradict a sentence, found in ScnwauBe’s “Die 
Morphologie der Missbildungen” where he says: “das Vorderhirn ist 
bei den Cyclopen nie in Hemisphären geteilt”. I must assert, that 
in all cases of cyclopian brain the hemispheres are well differenti- 
ated at the occipital end. 
At the frontal pole however they are often united, although in 
one of the cases then described, there was also a sagittal fissure at 
the frontal pole of the hemisphere. 
I therefore deny that the examination of cyclopian brains should 
give any support to the supposition that the terminating-time of the 
cyclopia must be placed in a period, preceding that in which the 
sagittal fissure of the telencephalon appears. Also the view that 
eyclopia is mevitably accompanied by arhinencephalia, I could only 
accept under certain reserve. 
In fact, in all the cases which I examined, the bulbi olfactorii 
and the lobi olfactorii anteriores were missing. But the lobi olfactorii 
posteriores were present. They are found along the mesial line of 
the brain-base. There they were placed next to each other, because 
the brain-base between them was missing. 
Ordinarily eyelopian brains are partially arhinencephalic, missing 
only the frontal part of the rhinencephalon. 
Since then I have prepared the brains of several cases of cyclopia, 
largely differing between each other. 
Now I believe that there is another monstrosity, the so-called 
synotia, nearly related to the cyclopian one. The former is often 
combined with the latter. 
Through the kind cooperation of Professor Kouwer and Dr. Vrr- 
MEULEN I obtained possession of such-like monstrosities. 
19 
Proceedings Royal Acad. Amsterdam. Vol. XXII. 
