250 



THE AMERICAN NATURALIST 



[Vol. LVI 



black in t'he fowls is only slightly above the mid point 

 between Columbian and grade-4. 



An F2 generation has not yet been raised from the 

 cross of typical Columbian X Buff, but some data are avail- 

 able on the F2 generation from the cross of the hetero- 

 zygous Light Brahma which was first used in crosses 

 with buff. This male was lighter, than typical Columbian, 

 about grade- 1. His offspring were not graded but had 

 slightly less black than the offspring of the typical Co- 

 lumbian male, averaging about grade -3. The amount 

 of black was similar in the Columbian and buff progeny. 

 When these F^ buffs were bred inter-se the grades of the 

 Fg adult fowls were as follows: 



The variation in amount of black pigment was practi- 

 cally continuous, except thait the Columbian parental 

 type was not recovered. No buffs were obtained which 

 were entirely free from black in tails or wings. 



The Fi Columbians were backcrossed with a pure Buff 

 Rock male which showed only faint traces of black stipp- 

 ling (mealiness) in the tail. The progeny of this cross 

 were of the following grades: 



Whites (Columbians) and buffs combined: 

 Columbian —1 —2 —3 —4 Self 

 2 a 9 13 4 



The amount of black in these fowls was obviously much 

 less than in the ¥^ generation although the same grades 

 were represented. In four fowls (three buffs and one 

 white) no trace of black pigment could be detected. 



It is ob\dous from these facts that as regards the black 

 component of the Columbian pattern, the Light Brahmas 

 and the buffs used differ only in amount. A blend oc- 

 curs in the first generation followed by segregation in the 

 second and backcross generation. It is probable, there- 



