( 376 ) 
index it was found, that in the adult skulls it varied between 67 
and 56, while the index value of the juvenile skulls amounted to 50 
and 54. With the latter of these two the first molar had already 
appeared, while the medial incisor had been changed. 
By what precedes it is sufficiently proved that in all Anthropoids 
the foramen magnum during the juvenile period is shifted in a 
backward direction. At what moment this shifting begins and whether 
it does so immediately after birth I cannot decide, having no skulls 
at my disposal in which the milk teeth are not already fully developed. 
Several investigators have of late years pointed out that the infantile 
skull of the Anthropoids stands morphologically nearer the human 
skull than that of the adult Anthropoids. This phenomenon has 
especially been discussed in regard to the frontal vaulting. As I have 
the intention systematically to investigate the whole skull this point 
will also in due time be dealt with; the remark may here suffice 
that also in regard to the foramen magnum, this greater agreement 
is confirmed. For since the basal index of the infantile skull is 
without exception lower than that of the adult one, it conies nearer 
the index of the human skull. This approach is so close that the 
lowest index of the infantile skull of the Anthropoids, namely 50 
with Chimpanse, Gorilla and Orang, is equal to the highest I found 
with Zeelandians and negroes, while with Javanese even a higher 
index was found. Very important and instructive is a superposition 
of the mediagrams of the young Gorilla skull with basal index 50 
and a Zeelandiau skull' of the same index, which will be given in a 
following communication. 
There remains to be shown that the same phenomenon which was 
stated for the skull of the anthropoid apes obtains in man and that 
here also the basal index of the child is lower than that of adults. 
The foetal skulls will be left out of account here and only the results 
obtained with infantile skulls will be given. They will be given as 
averages for the groups mentioned in the enumeration of materials. 
Basal index of the skulls of children. 
10 skulls of 0- 
1— 2 
3— 4 
4— 5 
8—10 
10—13 
year: 
average 41.99 
40.4 
40.4 
41.5 
40 .— 
40.7 
