223 
F, also appears in this generation. There is also a reduction in the 
number of pencillings characteristic of the parental species (E. nyc- 
themerus <¢). 
The F, generation (F, inter se) has reproduced some F, hybrid 
features together with clear evidence of segregation of unit-characters. 
This, however, cannot be discussed in the absence of a detailed state- 
ment of results. 
(2) The Central Rectrices. With regard to the two central rec- 
trices of the hybrids, the first hybrid generation and second hybrid 
generation (i. e. F, inter se), are both polymorphic, and in both gene- 
rations the most interesting results can be expressed by saying that 
three transpositions of colour or pattern, or both have occurred 
(a) From the hen of one species to the cock of the hybrids. 
(b) From the lateral rectrices of the same species to the central 
rectrices of the hybrids. 
(c) The orientation of pattern has been reversed in the course 
of this transposition and there has also been a mutual rever- 
sal of adjacent colour areas. 
(3) The Primaries and Secondaries. In the F, generation poly- 
morphism is shown and there is some indication that one of the 
colours characteristic of the Swinhoe hen has been transposed to the 
opposite sex in the hybrid. In the F, generation (F, inter se) the 
chief feature is the manifestation of a complete segregation of one of 
the Swinhoe cock characters in one of the birds. In another bird, 
a new character not seen in F, appears. In a sense, it represents 
a somatic mosaic of the modified pattern of both parental cock species. 
The other members remanifest the hybrid polymorphism shown in the 
F, generation. 
For the examination of the skins upon which these results are based, 
I am indebted to the kindness and generosity of Mrs Hara THomas, who 
in 1907, at my suggestion, commenced the breeding experiments which 
are here described, as well as others which yet remain to be dealt 
with. The object I had in view in suggesting these experiments was 
to ascertain how far Mendelian principles held true, if true at all, in 
the transmission of characters among the hybrid descendants of crossed 
species, as distinct from those of varieties. I may add that there is 
evidence of Mendelian segregation but its nature is such that the 
adequate discussion of it can only profitably be undertaken when the 
fuller paper with the details of results is published. 
