No. 528] 



NOTES AND LITERATURE 



751 



that the Barred Plymouth Rock female does not transmit this 

 quality directly. The facts appear to indicate that high egg 

 laying quality is a sex limited factor like barring in the Barred 

 Plymouth Rocks. Barred Plymouth Rock females would thus 

 transmit high egg laying quality to their male offspring but not 

 to their female olfsprinn'. while Barred Plymouth Rock males 

 would transmit it to both sexes. 



Shank color was also found to be a sex limited character. 

 Both breeds have yellow shanks, though the Barred Plymouth 

 Rocks sometimes have black pigment in the shank epidermis. 

 In the cross Barred Plymouth Rock male on Cornish Indian 

 Game female the progeny all have yellow shanks. In the re- 

 ciprocal cross the male progeny have yellow shanks, while the 

 female progeny have black shanks. The authors suggest that 

 shank color behaves like barring in transmission. There is, 

 however, evidently some difference, for here we get females 

 showing a character not possessed by either parent. The writer 

 would suggest, as a possible explanation of the behavior of 

 shank color, that the chromosome which determines the female 

 sex in the Barred Plymouth Rock probably has black shank 

 latent and that this character is aroused into activity by the 

 cross. The F 2 generation of this cross will probably give some 

 important information on this point. Fortunately, these care- 

 ful and indefatigable workers will continue these investigations. 



In down color the hybrid chicks from the reciprocal crosses 

 were alike but unlike either parent, being darker than the dark- 

 est parent. 



The F, generation between pea comb (Cornish Indian Game) 

 and single comb (Barred Plymouth Rock) gave all gradations 

 from pea to single. There were more pea combs in some fami- 

 lies than in others. 



In body shape the males in the F x generation were all of the 

 Cornish Indian Game type. The females were intermediate be- 

 tween the two breeds in this respect. The barred females — that 

 is, those produced from Barred Plymouth Rock sires — were more 

 like the Barred Plymouth Rock in body shape, and the black 

 females more like the Cornish Indian Game. 



In this paper the authors give the results of extended investi- 

 gations relating to inheritance of the Plymouth Rock Barring. 

 The paper is limited to the study of the cross between Barred 

 Plymouth Rocks and Cornish Indian (James. The results con- 



