437 



curve, this difference would appear in the shape of the curve, viz. 

 a twotoppedness. One top would be found at about 75 and another 

 at 85. As far as in literature such curves have been communicated, 

 no distinct tvyotoppedness is to be seen (Retzius and Fürst ^), Bolk"), 

 E. Fischer'); comp. also Welcker*) S. 42.) Also in the curves of 

 my uiaterial they are failing (Fig. 1 — 5). This is possible, when the 

 dolichocephalic type, whilst crossing with the brachycephalic, origin- 

 ates equally all possible intermediate shapes, but still the more so, if 

 there are not two types, but several. The solution of these problems 

 is being searched for by the experimental science of heredity. 

 Generally biological the question is: are the dolichocephalic and 

 the brachycephalic headforms characteristic marks of distinction 

 between two races, consequently of elementary species, and expressed 

 mendelianly : is the headform determined by units of heredity 

 and by how many? Thus the investigation of the headform is a 

 hereditary-analytical problem, to be studied by family investigations. 



The material, of which the composition is represented by the 

 curves (Fig. 1 — 5), consists of families from one generation (brothers 

 and sisters), from two generations (parents and children), and from 

 three generations (one to four grandparents, parents and children). 



At a tirst glance at the material the impression is made that of 

 a family of brothers and sisters the brothers often have lower indices 

 than the sisters. In the curves 6« and 6^ 169 brothers and 169 sisters 

 have been brought together, who are chosen in such a welj that 

 constantly from each family as many brothers as sisters have been taken. 

 If consequently two brothers and two sisters of one family have been 

 measured, then two brothers and two sisters (i.e. the two elder) 

 have been inserted into the curves. From these curves it appears 

 still more distinctly than from the curves of the total number of 

 men and women (Fig. 2 and 3) that as a rule the men have a 

 somewhat lower index than the women. Of the men (F'ig. 2 and 3) 

 one top lies at 77,5, and another at 82, of the women the top lies 

 at 80; of the brothers (Fig. 6«) the top lies at 79, of the sisters at 

 81,5. 33 brothers and 12 sisters have indices under 77. The 

 variability of width of the sisters (74 — 89) is likewise somewhat 

 smaller than that of the brothers (72 — 90). 



1) Retzius und Furst. Anthropologia Suedica. 1902. 



') L. BoLK. De bevolking van Nederland in haar anlhropologische samenstelling. 

 {Uit Gallee. Het Boerenhuis. Utrecht 1908). 



^) E. Fischer. 1. c. 

 •> *) H. Welcker. Untersuchungen iiber Wachsthum und Bau des menschliclien 

 Schadels. 1. Theil. Leipzig. 1862. 



