870 



has a large and wide head, whilst the mother is mesocephalic and 

 has a small head. A beautiful case is fam, 147 with 9 sons and 2 

 daughters. This case can likewise be conceived as an example of 

 the type of heredity of Nilsson-Ehle with greater or less dominance 

 of the great lengths and breadths with coupling. The index of one 

 son surpasses that of the father, one agrees with it, one is a little 

 lower; one daughter has an intermediary index whilst of the other 

 children the indices differ little from that of the mother, and two 

 surpass it somewhat. 



The families 179c, 185 and 32/' show all a slight degree of pre- 

 dominance; one might class them with table II, 179c and 195 

 likewise with table VII. 



Especially the families 68 and 76 offer great difficulties for the 

 explanation. The fathers have in these cases rather low indices and 

 large heads, the mothers high indices and rather laige and broad 

 heads. In the first case all four children have the same or lower 

 indices than the father, in the second case two of the three children 

 have somewhat lower indices than the father, and one has an inter- 

 mediary index. These two families withdraw themselves from the 

 explanation tried here (comp. p. 874). 



The family 147 of table IV mentioned before shows a phe4iomenoii, 

 that is likewise expressed more or less in other families. We have 

 here to do with parents with diverging indices (85 and 79); of 

 the eleven children three sons have indices nearly equal to that of 

 the father, whilst of the eight other children the indices correspond 

 with that of the mother (78 — 81.8). Apparently there is here 

 analogy with the mutation-crossings of de Vries ^) segregation in 

 F, and simple repetition of the properties of the parents. As this 

 crossing can also be explained by combination of factors, as we 

 indicated above, and the formula DR X RR = DR -\- RR can be 

 applied, in which consequently in this case the father is conceived 

 as DR and the mother as RR, and a similar result, that is a 

 Mendelian one (Pearl) has been obtained in more complicated 

 cases, we shall as yet conceive this crossing as not clashing with 

 the rules of segregation of Mendel. 



Still something more is to be said about the heredity of the 

 short, small head. In family 17 (table I) suddenly two short-headed 

 ones appear among the children; the mother's sister is likewise 

 short-headed (L 17.4 B 14.8 Ind. 84.7). Of several families of table 

 II, where one of the parents has a large and broad head, several 



1) Hugo de Vries. Die Mutationstheorie II and Gruppenweise Artbildung 1913. 

 S. 109. 



