Ill] 



The 



Comb 



Consistent with this result were the offspring obtained 

 from first-cross RP x S, for this mating gave the ratio 



iRP : iR : \P : iS. 



As it was already established that R and P were each 

 dominant to S, the inference was certain that the gametes 

 produced by the F l (RP) birds were RP, R, P, and 5 in 

 equal numbers. 



The whole series of phenomena may be represented as 

 due to the combinations of two pairs of allelomorphic 

 characters or factors, namely 



1. Rose (domt) R, absence of rose (rec.) r. 



2. Pea (domt) P, absence of pea (rec.)/. 



Reference to the diagram of combinations shows that 

 the two " absences " of rose and pea respectively will meet 

 once on an average in 16 times, and to such a meeting 

 without doubt the appearance of the single combs as a 

 novelty, in 7%, is to be ascribed. 



In the early years of this experiment, knowing that R 



B. H. 



