of Heredity 25 



manifested by the cross-bred is called "dominant" 

 and the parental character, green, not manifested, is 

 called recessive. 



(2) The cross-bred may present some condition 

 intermediate between the two parental forms, in 

 which case we may still retain the term "blend' 1 

 as applied to the zygote. 



Such an " intermediate " may be the apparent mean 

 between the two parental forms or be nearer to one 

 or other in any degree. Such a case is that of a 

 cross between a rich crimson Magenta Chinese Prim- 

 rose and a clear White, giving a flower of a colour 

 appropriately described as a " washy ' magenta. 



(3) The cross-bred may present some form quite 

 different from that of either pure parent. Though, 

 as has been stated, nothing can be predicted of an un- 

 known case, we already know a considerable number 

 of examples of this nature in which the mule-form 

 approaches sometimes with great accuracy to that of 

 a putative ancestor*, near or remote. It is scarcely 

 possible to doubt that several though perhaps not 

 all of Darwin's "reversions on crossing" were of 

 this nature. 



Such a case is that of the "wild grey mouse " produced 

 by the union of an albino tame mouse and a piebald 

 Japanese mouse*. These "reversionary" mice bred 

 together produce the parental tame types, some other 

 types, and " reversionary " mice again. 



From what has been said it will now be clear that the 

 applicability of the Mendelian hypothesis has, intrinsically, 



* See von Guaita, Ber. naturf. Ges. Freiburg x. 1898 and xi. 1899, 

 quoted by Professor Weldon (see later). 



