115 
KiikentHaL and Zrenen) of the suleus temporalis superior, the latter 
has not only pushed down the 5 suleus, but it too has divided the 
lateral pli de passage as it were into two portions. In this drawing 
one could speak of two lateral plis de passage, which therefore run 
towards the occipital surface. But as this example is an exception, 
it cannot be counted of much worth. Yet it proves that where in 
the higher development the complex of sulei becomes more com- 
plicated, it can be of influence on the image of the plis de passage. 
The embryonal material could show us the way in this case. 
From what is found in anthropoids follows that the ape-tissure on 
the whole is less developed than in semnopitheci and related monkeys. 
It gives the impression as if the suleus begins to contract. 
CONCLUSIONS. 
1. The plis de passage in foetal life are lying on the surface. 
2. They form, lying on the surface, the communication between 
the lobi parietalis and temporalis with the lobus occipitalis. 
3. In semnopitheci, macaci and related monkeys only three plis 
de passage are known: 
a. gyrus annectens lateralis, lying between the m and 5 suleus. 
b. gyrus annectens interpositus, lying on the mantle surface, 
forming the continuation of the arcus parieto-occipitalis. 
c. gyrus annectens medialis, forming the communication between 
the cuneus and praecuneus, lying above of the fissura calearina. 
4. When the ape-fissure is formed on the border of the parietal 
and occipital part (semnopithecus, macacus ete), then the lateral 
and interposed-gyrus annect. are pushed totally or partially in the depth. 
5. When the ape-fissure is formed on the occipital surface (ateles, 
nycticebeus tardigradus etc), then it does not come in contact with 
the plis de passage and these therefore remain on the surface. 
6. In the anthropoids the ape-fissure is considerably less developed 
than in semnopitheci ete. 
Physiology. — “Quantitative determination of slight quantities of 
SO,. UL. Contribution to microvolumetrical analysis’). By Prof. 
H. J. HAMBURGER. 
(Communicated in the meeting of April 28, 1916). 
1. Zntroduction. 
Repeatedly physiologists and clinicists find themselves confronted 
by the task of determining quantitatively very slight quantities of 
some substance and if no good titrationmethod is available, the 
1) A more detailed account will be given in “Biochemische Zeitschrift” 1916. 
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