i$6 MENDEL'S LAWS 



house-mouse resembling in size, colour, and wildness the wild 

 house-mouse " 1 is produced ; when yellow-grey Belgian rabbits are 

 crossed with white (albino) Angoras the offspring have " wild-grey 

 coats indistinguishable from those of the wild-grey." 2 When Mr 

 Hurst crossed Black Hamburgh with Buff Cochin poultry, " in the 

 first plumage the two sexes are quite distinct. The cockerels had 

 golden-brown hackles, red-brown saddles, black and brown tails and 

 wings, and buff-brown breasts regularly spangled with black. The 

 pullets were as dull and sober in colour as the cockerels were 

 brilliant, being black intermixed with light and dark brown, with 

 darker tails and heads and spangled breasts. It seems rather 

 curious that a cross between two breeds, each of which has normally 

 similar plumage in both sexes, should produce offspring in 

 which the two sexes are so distinctly differentiated." 3 Among 

 domesticated pigeons the plumage of the wild blue-rock, and 

 among poultry that of the ancestral Gallus bankiva may reappear 

 when domesticated breeds are crossed. When the horse is crossed 

 with the Burchell zebra, which has a few broad stripes, the offspring 

 present the narrower and more numerous stripes of a remote 

 ancestor. 4 Similar instances of 'reversion' are common amongst 

 plants ; for example, if a jonquil be crossed with a daffodil, Narcissus 

 odorus results. 5 



263. Dominance may be influenced by the environment, as in 

 the case of Ewart's pigeons, whose offspring reproduced the 

 characters of the English parent when the Indian parent was ill, 

 but those of the latter when its health was good. 6 



264. Dominance may be affected by the sex of the parent. 

 Thus, when white Leghorn and Indian Game poultry are crossed, 

 " all male cross-breds and female cross-breds from Indian Game 

 mother almost always have the ground colour white, but female 

 cross-breds from white Leghorn mothers have the ground colour 

 more or less dingy-brownish white." 7 " Booting (feathered foot) is 

 always dominant when the feathered form is the mother, no matter 

 what the race." 8 " The canary has two forms which are both in a 

 sense albino, the yellow and the cinnamon. When green (viz. non- 



1 First Report to Evolution Committee, p. 145. 



2 C. C. Hurst, Experimental Studies on Heredity in Rabbits, p. 301. 



3 Second Report to Evolution Committee, p. 135. 

 Ewart, The Penicuick Experiments, p. 92. 

 Vernon, Variations in Animals and Plants, p. 169. 

 See 132. 



First Report of Evolution Committee, p. 99. 

 Davenport, Inheritance in Poultry, p. 86. 



