738 



THE AMERICAN NATURALIST 



[Vol.XLIX 



nation really differing from the black-eyed whites in the 

 substitution of a "self" bearing gamete for a " piebald" 

 one in the zygotic formula. The result is an animal like 

 Type "A," Fig. 5; Type "B," Fig. 6 shows the other F 1 

 type which is entirely free from the W factor and which 

 is merely a heterozygote between "self" and "piebald." 



If class "A" animals are crossed inter se we should on 

 this new hypothesis expect the following results. 



1 WWSS not developed 



2 WwSS very dark spotted 



2 WWSsp not developed 



4 WwSsp like parents (type "A") 



1 WWspsp not developed 



2 Wwspsp black-eyed white 



2 wwSsp "self" or "self " with white ventral patch (type "B") 



Four of the 16 zygotes in F 2 would have two doses of 

 W and would not develop. Of the remaining 12, seven 

 would have some degree of white spotting depending upon 

 whether they were WwSS, WwSsp or wwspsp in formula ; 

 three would be "solid" colored or like type "B" of F t 

 and two would be black-eyed whites. 



On this hypothesis the F 2 generation would be as fol- 

 lows: 



Solid 15 15 



Spotted 31 35 



Black-eyed whites 11 10 



A further test of the nature of type "A" is possible. 

 If they are bred to piebald animals, four classes of young 

 should result as follows. 



57 



black-eyed whites 

 solid colored 

 piebald 



Lumping together the WwSsp and the wwspsp animals 



