150 LOTSY AND KUIPER, A PRELIM. STATEMENT OF THE RESULTS OF MR. 
birds were as like as two peas. This was the opinion of all the 
members who attended at the meeting of the Dutch Society for 
scientific culture where the birds were demonstrated. 
In 1920 a new pen was bred from the same parents 413.1 Silky 
x 201.7 ¢ Bankiva 6 birds (4 cocks 413.11; 413.12; 413.13; 413.14 
and 2 hens 413.15, and 413.16). 
They all had a rose comb too. : 
It seemed therefore that a difference between the reciprocal 
crosses, not caused by heterozygosis of the parents, existed indeed. 
If we had limited our experiments to these animals and their 
offspring, our results would have been for a great deal in accor- 
dance with those of v. TSCHERMAK. — 
But by extension of the experiments this proved to be a mistake. 
In the F, bred from the Silky-mother only rose combs were 
developed, the F, from Bankiva-mother gave only single combs. 
We thought these results very curious, and resolved upon a 
repetition of both crosses with other birds the following year. 
Now in the cross Bankiva 220.82 x Silky 446.1 7 18 pullets were 
born 11 with rose comb 7 with single comb. 
In the cross with Silky mother we got from Silky 444.3 © x Bankiva . 
202.6 ¢ an F, of 5 birds all with rosecomb. 
So in total the results were: 
Bankiva-mother. 


Cocks. Hens. 
rose comb. single comb. rose comb. single comb. 
630.1 414.1 630,7 - 4144. 
630.4 414.2 630.10 414.5 
. 630.16 414.3 630.11 4146 — 
Ban, 630.2 630.12 414.7 
630.3 630.13 630.9 
630.5 630.14 630.15 
630.6 630.17 SEE 
630.8 630.18 
8 les 
Or birds with rose comb 37 + 8 9 = 11 
and birds with single comb 8 3 + 6 9 = 14. 

