424 THE AMEBIC AN NATURALIST [Vol. XL VII 



C 2 B 2 N 2 fJ 2 



forming gametes 



CBNfl ■ CBNfl. 



As to the zygotic constitution of the Black Hamburg 

 2? there is no reason for supposing that they contain 

 either B or I, although they do contain C and A 7 ; also 

 they may be looked upon as heterozygous for F. We 

 may therefore write their zygotic formula as 



C 2 b 2 N 2 Ffi 2 



forming gametes 



CbNFi ■ CbNfi. 



But, since, in all probability, none of the birds in these 

 experiments lacks the factors C or N, we may leave these 

 out of consideration, thus writing the W. L. J 1 formula : 



B 2 fJ 2 



forming gametes 



Bfl ■ Bfl, 



and the B. H. $ formula 



