106 
made a difference between the fissura parieto-occipitalis lat., and the 
ape-fissure. According to them, these sulci are to be considered as one. 
The researches of KiikENTHAL and ZIeHeN *), KOHLBRUGGE *), ZUCKER- 
KANDL*) and myself*) however have pointed out, that a sharp 
distinction between those two sulci has to be made. 
Although the suleus parieto-occipitalis lateralis ( + m’ KiikENTHAL 
and ZteHeN) in cynopithecini will nearly always be found in the 
ape fissure (K.), yet it may not be identified with it. 
In the interpretation of GRATIOLET therefore this change has to be 
made, that the first two plis de passage do not lie in the fiss. par. 
occ. lat. but in the fissura simialis. 
His view about the 3 and 4 pli de passage can remain 
unebanged. 
As to the two inner or medial plis de passage, the upper should 
be lying in the fossa par. oce. medialis, while the lower remains 
on the surface. 
The upper originates from the top of the praecuneus, then runs 
downwards, afterwards climbs to the top of cuneus, where it is 
united to the 1st lateral pli de passage. 
The lower unites the lower part of the cuneus with the base of 
the praecuneus and it forms partially the upper ridge of the fissura 
calcarina. This convolution is called at present the gyrus cunei 
of Ecker. 
lt is comprehensible that after GRATIOLET the plis de passages 
have often been the subject of study. 
As however the sulci in general, and those of the occipital part 
in particular show a number of varieties, as moreover the material, 
which was examined, gradually took greater dimensions, then it is 
not strange that the conceptions about the plis de passage altered. 
It would take me too long to go into particulars with respect to 
the opinions and contradictions met with, and therefore it will 
suffice to communicate only the most interesting items of them. 
BiscHorr is of opinion that between the first outer (parietal) and 
upper (medial) pli de passage, there does not exist a difference. If 
the first is drawn into the depth, then it continues into the second. 
1) KükENTHAL, W. u. ZiegeN Tu. Untersuchungen über die Grosshirnfurchen 
der Primaten, Jenaische Zeitschr. Bd. 27, 1895. 
2) Koutpruaer. J. H. F. Die Variationen an den Grosshirnfurchen der Affen 
mit besonderer Beriicksichtigung der Affenspalte. Zeitsch. f. Morph. u. Anthr. 1903. 
35) Note 2 p. 105. 
4) 1e. 
