8 4 



INHERITANCE IN POULTRY. 



nate over pigmented plumage. It appears, then, that the patent character 

 is, in general, but with some exceptions, dominant over the corresponding 1 

 latent character. / 



INHERITANCE OF OI<D VS. NEW CHARACTERISTICS. 



Standfuss (1896, p. 1 1 1), as a result of his hybridization of-.:rnoths, concluded 

 that hybrids resemble the older species. De Vries '{1902^, pp. 33-42, and 

 1905, pp. 280, 281) cites several instances of the prepotency of the phyloge- 

 netically older characteristic. Bateson and Saunders (1902, p. 137), how- 

 ever, point out that younger characteristics sometimes dominate, and cite 

 pea and rose comb, extra toe, and the polled condition of cattle as examples. 

 Correns (1905, p. 463 et seq. ) describes a case of petaloid calyx a new 

 characteristic which is dominant over the normal form. Correns (1905*, \ 

 p. 13), indeed, concludes that in general the phylogenetically more advanced 

 characteristic the later originated, younger characteristic dominates. 



Let us see what evidence poultry hybrids have to offer bearing on this point. 



This table shows that of nineteen characteristics (No. 10 being left out of 

 consideration), nine old ones are dominant and ten new ones. Clearly, dom- ( 

 inance of characteristics in poultry is not determined b)^ the age of the 

 characteristic. 



s^ DOMINANCE AND RECESSIVENESS. . ^_S\ 



Mendelian-dominance and recessiveness with segregation of characteristics 

 in the gametes are not UBiversaLconcomitants of hybridization. Mendel knew 

 it (Correns, 1905") ; de Vries founds his system on the fact ; Correns lays 

 stress on it ; Bateson and Saunders (1902, p. 152) recognize it, but consider 

 the exceptions insufficiently known. The characteristics that I have crossed 

 show always segregation excepting extra toe and perhaps also melanic foot 

 and beak color. These are among the positive variations of de Vries,. which, 

 in accordance with his system, we should not expect to i; mendelizer y> As 

 stated, other positive variations, however (pea comb and muff), seem to 

 mendelize. 



