RESEARCHES INTO ANTHROPOLOGICAL HEREDITY 193 



plain blue-eyed parents will as a rule have only plain blue-eyed 

 children. From table 1 b it is plain enough, however, that this rule 

 is not without exception. In the series here given there were almost 

 exactly 10 per cent exceptions from the rule. These 10 per cent had 

 the eye colour of their grandparents. In the series given by Davenport 

 the rule was not without exception either. Hurst found no exception 

 from the principal rule, at which he seems to be rather astonished. 

 »In accordance with the Mendelian principles the extracted simplex type 

 breeds true to the simplex character without reversion to its duplex 

 ancestors. In view of recent Mendelian experiments with plants and 

 animals, it did not seem impossible that some simplex individuals at 

 least might be carrying factors, which on meeting, in the process of 

 fertilization with other complementary factors, might give rise to re- 

 versions of the duplex type; but so far, no such cases have been 

 found.» Nor may the possibility be put out of question that the pre- 

 sent case illustrates what the Germans strikingly call a new »Ver- 

 schmelzungsgenotypus», being recessive to both ancestors, the plain 

 blue primitive type and the plain brown one. There are, as I have 

 pointed out elsewhere ^, also other symptoms indicative of such an ex- 

 planation. Both Davenport and Hurst seem to take the view that 

 mixed eyes and »the ringed pattern» represent independent types. 

 Davenport is decidedly of the opinion that these mixed eyes are re- 

 cessive to plain brown eyes, but dominant to plain blue ones. 



Table 2 gives the cases where the couple of parents had >> double» 

 eyes. As will be seen, the children of 5 of these couples had all 

 »double» eyes. In the other 8 couples some of the children had double 

 eyes and some simple ones. In these two groups 38 children were 

 found with »double» eyes and 11 children with »simple» eyes. The 

 couple in the former group marked no. 56 is probably homozygotic 

 with regard to eye type. As to the rest, the number of children is 

 so small that no conclusions can be drawn with regard to this point. 

 If we take for granted that serial numbers 1, 3, 50 and 74 were he- 

 terozygotically brown — and this assumption seems to be the most 

 probable in our population — there will be 32 children with double 

 eyes and 11 with simple eyes in this group. In the case where both 

 parents are heterozygotically brown ^4 of their offspring will be brown 



^ H. Bryn: Trondelagens Antropologi. Det Kgl. Norske Videnskabers Selskabs 

 Skrifter, 1917, Kr 2. 



