326 
Fig. 2. 
one of the two factors entering with each gamete. In the tbllo- 
wing year a single F2 family was raised and consisted of 51 
normal fertile^ 30 normal sterile, 33 cretin fertile, and 1 cretin 
sterile.^) The cretin character behaved as recessive to the normal 
flower, but the relative distribution of the different characters 
evidently pointed to some form of repulsion between the normal 
flower and fertility. Had it not been for the appearance of 
the Single sterile cretin we conld have regarded this case as 
one of complete repulsion between the factors N and F. The 
problem was to account for the sterile cretin, and at the time we were 
inclined to regard it as due to an unaccountable failni'e of repulsion 
between N and F. Lack of opportunity prevented us from 
following up this case in 1910, but in the present year we sowed 
the seed of the rest of the Fi plants harvested in 1908 and 
obtained details of eight more families which are set out in the 
accompanying table (Table I). 
1) In this family and in one of those subsequently grown both light 
and dark axilled plants occur ed. In each case the dark axil went in from 
the fertile cretin parent, and in F2 there is some coupling betsveen the 
dark axil and fertility. The numerical results howerer are comp lex and 
must be left over for discussion until more material is available. 
