HOUWINK’S EXPER. CONC. THE ORIGIN.OF SOME DOMESTIC ANIMALS. 143 
The reciprocal F, consisted of only two animals with single comb, 
feathers white with few black stripes, legs clean; leg colour red gray. 
Of course this reciprocal Fy, containing only two individuals, 
is too small to draw any conclusion from, and the fact, that the 
other F, is not homogenous, gives a strong indication of hetero- 
zygosis in at least one of the „guaranteed pure” breeds. This 
fact need not astonish us. Everyone knows the disappointment 
high-classed exhibition-animals often give in their offspring. This 
won't change until the examination takes place not only from the 
exterior but from the offspring too. 
Prof. v. TSCHERMAK’S case seems a clear proof of this these. It is 
only strange the author did not draw this conclusion himself from 
his „exception”’. 
And now about the second series of experiments. 
Barred Plymouth Rocks. 


Hen. Cock. 
Comb. _ single-low ditto 
Feathers white and brown black white gray and brown- 
narrow bars black broader bars 
Legs clean ditto 
Legcolour browngray redgray 
Partridge-Leghorn. 
Comb. single, very high. ditto. 
Feathers brownandblack, keeled | brown partly with greenish- 
and speckled. black and with some white. 
Legs clean ditto. 
Legcolour | orange yellow. 


The necessity of large Fy’s of both sexes in the reciprocal crosses 
needs no demonstration in connection with these differences. 
In fact v. TSCHERMAK bred only: 
Plymouth Rock © x Partridge Leghorn ¢: 2 Cocks. 
. Partridge Leghorn 9 X Plymouth Rock ¢:1 hen and 2 animals, 
died as pullets. 
The author means to explain the characteristic differences between 
the products of the reciprocal crosses as an influence of the sex 
of the parents on the development of the inherited characters. 
In F, the paternal type is decisive upon the form of the comb, 
