105 
Amsterdam and Rotterdam. The averages of these will be mentioned 
separately, and this will give an explanation why they were excluded 
from the calculation of the provincial averages. 
Let us consider first the Index cephalicus. The following tables 
show the value of the Index cephalicus in the different provinces. 
Province | denice “people 
Groningen 81.2 290 
Drenthe at) 460 
Overijsel 81.4 467 
Friesland 80.4 168 
N. Holland 80.5 136 
Utrecht 80.5 | 430 
Gelderland | 80.4 1379 
Z. Holland | 19.6 1239 
Zeeland | 80.8 | 1243 
N. Brabant | 81.5 883 
Limburg | 80.6 1234 
Amsterdam 79 590 
Rotterdam 19.2 256 
In this table are mentioned also the numbers related to Amsterdam 
and Rotterdam, these data will be referred to later on. From the 
table mentioned above, it appears that taking the small geographical 
extension of our country into consideration, the Index cephalicus 
is rather variable, as it oscillates between the two extremes 79.6 
(Z. Holland) and 81.5 (N. Brabant). 
On. comparing the provincial averages with each other, one cannot 
help noticing a certain regularity in the variability. The three 
northern provinces: Groningen, Drenthe and Overijsel form more or 
less one group, in which the Index cephalicus attains the value of 
81 or surpasses it even. 
One might add to this north-eastern territory the so-called Achter- 
hoek of Gelderland of which 313 persons are measured with an 
average Index cephalicus of 81.1. This north-eastern part of our 
population forms, as is generally known, linguistically and ethnolo- 
