SEX-LINKED INHERITANCE IN POULTRY 165 



capable of becoming homozygous. Reciprocal crosses with 

 such a race give unlike results, because the female transmits 

 the character to all her offspring, but the male transmits it 

 to only half his offspring, viz., the females. 



2. Poultry type. Another type of sex-linked inheritance 

 exists in which the sex relations are exactly reversed. This 

 was first observed in the moth, Abraxas, but more familiar 

 cases occur in poultry, for which reason it may be called the 

 poultry type of sex-linked inheritance. Here the male is the 



Fio. 121. Reciprocal cross to that shown in Fig. 120. P, parents, unbarred male, barred female; Fi, 

 barred males, unbarred females (criss-cross inheritance); F2, barred and unbarred birds equally nu- 

 merous in both sexes. 



homozygous sex, the female being heterozygous. This condi- 

 tion is found in moths and in certain birds, viz., in domestic 

 fowls, pigeons, ducks and canaries. As an example we may 

 take the inheritance of the color pattern, barring, in crosses of 



