+ = PE A CRU 





RE ET CS pt nej 
MICROBRACHYCEPHALY. PREPOTENCE. (233) 41 
brachycephalic with the indices 81, 81, 82, 83, 85, 86, 87, 88. So as 
regards the indices of children there is here an evident dominance of 
the high index over the low one. However, accepting for the parents 
the formula DR x DR, then we may not speak of dominance, 
for dominance is the phenomenon that from a cross of two homozy- 
gous individuals (P’s) the bastardgeneration (F,) has the appear- 
ance of one of the parents. In family 324b (and 245a and 32c) 
however the parents are not homozygous according to the data of the 
grand-parents. So here there cannot be dominance, but there must be 
segregation, according to mendelian interpretation. 
According to the constitution of the father’s index DD, 1. e. the 
possibility which is called in the 2n4 place, then the formula of the 
parents becomes DD x DR = DD + DR and then all children can 
have a high index. | 
If we see in the high indices of the children in the families 324b, 
245a and 32c the prepotence of a high index of one of the parents, then 
herefrom results that individuals who possess a property in a hetero- 
zygous form can have some prepotence for this property. In this way 
consequently an essential difference between dominance and prepotence 
arises. 
For our theoretical understanding of heredity it is important that 
our material leads to the supposition, respectively the acceptation of 
such a difference between dominance and prepotence. 
Finally with regard to the cases 324b, 245a and 32c, we have still to 
point out the agreement in the character of the indices of the grand- 
parents of the families 324b and 245a. In family 324b the maternal 
grand-parents are macrodolichocephalic and microbrachycephalic (just 
macrobrachycephalic), in family 245a the paternal grand-parents are 
macrobrachycephalic and microdolichocephalic; in 324b the mother is 
microdolichocephalic, in 245a the father is macrodolichocephalic. In 
family 324b the paternal grand-parents are macrodolichocephalic and 
macrobrachycephalic, in 324b the father, in 245a the mother are in a 
high grade macrobrachycephalic. There is a special meeting of the 
- indices of the grand-parents which indicates that we have to look for 
a mendelian explanation of these cases. 
For a solution of this important question we must dispose of more 
cases and especially of more simple cases where, as in family 32c f. i., 
both grand-parents of one of the parents’ side have a low index and 
