194 



HALFDAN BRYN 



TABLE 2. 



The eyes of the couple of parents : double X double. 



and V4 blue. It might be said that the supposition of Mendelian inheri- 

 tance in the case of eye colour has so far proved true in this case. 



In table 3 I have placed all the cases where one of the parents 

 had simple eyes and the other double ones. If now all the parents 

 with double eyes were heterozygotes, half of the children would have 

 simple eyes and the other half double ones. I have listed 24 such 

 couples with 77 children in all. 38 of these had simple eyes and 39 

 double ones. These numbers correspond exactly to those expected if 

 the eye colour is inherited according to the Mendelian laws. We have 

 then to conclude that all or nearly all brown parents are heterozygotes, 

 and that brown homozygotes probably are very rare in our population. 



MIXED EYES. 



I have so far only discussed »double» eyes and »simple» eyes. 

 However, I have already pointed out that besides eyes generally called 

 brown ones also eyes known as mixed ones occur in the former group 

 (double» eyes). How are these mixed eyes inherited? I have 10 

 couples of parents with mixed eyes in my series. These have in all 



