HOUWINK’S EXPER. CONC. THE ORIGIN OF SOME DOMESTIC ANIMALS. 145 
only F,’s. CUNNINGHAM started with two Fy’s of the cross Silky 9 
X Bankiva ¢, bred in the Zoological Society’s Gardens. The Bankiva 
Cock was perhaps not absolutely pure, but there were no indications 
of crossbreedings in his pedigree. 
The characters of these parents tally in the main with those of 
our material. viz. 
Jungle fowl ¢. 
Comb, single. 
Colour of plumage, black red: breast and tailfeathers black, neck 
and saddle hackles yellowish red. 
Skin, unpigmented: comb and wattles red. 
Legs, clean, not feathered. 
Feet, normal, four toes on each. 
No crest on head. 
Silky Fowl 9. 
Comb, small rose. 
Colour of plumage, white. 
Skin, black; comb and wattles black-red, earlobes blue. 
Legs: feathered. 
Feet, with double hallux on both. 
Crest of feathers on head behind comb. 
The 2 F, animals showed: bankiva-coloured plumage of normal 
structure, rose comb, black pigmentation of the skin, double hallux, 
leg-feathering, crest. 
The author pointed out, that an other F, in the „Zoo” had a 
single comb. In relation to the double hallux all F‚’s were also not 
equal. In the Zool. Gardens the majority had double hallux on 
both sides, several had a normal and an abormal foot. In the author’s 
pair the cock had both feet normal, the hen both feet abnormal. In 
Fo CUNNINGHAM bred 10 chickens. In a diagram the segregation 
of characters is explained. This number is of course too small 
for accurate mendelian proportions. 
Our knowledge of the inheritance of the characters we are 
occupied with, can be summarized as follows: 
Double hallux is usually dominant to the normal four toed condi- 
tion, but irregularities are exhibited, by all cases of polydactylism. 
Some families run a perfectly regular Mendelian course, others 
Genetica IV. 10 
