SEX-LINKED INHERITANCE 



439 



in domestic fowls, pigeons, ducks, and canaries. As an example we 

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

 barred Plymouth Rock fowls. In reciprocal crosses between pure- 

 bred barred Plymouth Rocks and black Langshans (or another 

 unbarred breed), the results are not identical. If the barred parent is 

 the male (Fig. 91 and Table III), all Fi offspring are barred and in F2 

 all males are barred, but half the females are black and half are barred. 

 If, however, the barred parent is the female (Fig. 92 and Table III), 



TABLE III 

 REcn>ROCAL Crosses of Barred and Black Breeds of Fo\m.s 



Male Female 



Black X Barred 



Barred Blacl^ 



I Barred: i Black i Barred: i Black 



Male Female 



P Barred X Black 



Fi Barred Barred 



F2 Barred i Barred: i Black 



(See Fig. 91) 



(See Fig. 92) 



Fig. 92. — Reciprocal cross to that shown in Figure 91. P, parents, unbarred 

 male, barred female; Fi, barred males, unbarred females (crisscross inheritance); 

 F2, barred and unbarred birds equally numerous in both sexes. {From Castle.) 



