258 THE ZOOLOGIST. 



The F 3 generation (F 1 inter se) reproduces some F x hybrid 

 features, together with clear evidence of segregation of unit- 

 characters. This, however, cannot be discussed in the absence 

 of a detailed statement of results. 



(2) The Centkal Rectrices. — With regard to the two central 

 rectrices of the hybrids, the first hybrid generation and second 

 hybrid generation (F x inter se) are both polymorphic, and in 

 both generations 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. 

 (6) 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 



reversal of adjacent colour areas. 



(3) The Primaries and Secondaries. — In the F a generation 

 polymorphism is shown, and there is some indication that one 

 of the colours characteristic of the Swinhoe hen has been trans- 

 posed to the opposite sex in the hybrid. In the F 2 generation 

 (F 1 inter se) the chief feature is the manifestation of a complete 

 segregation of the Swinhoe cock character in one of the birds. 

 In another bird a new character not seen in F x appears. In a 

 sense it represents a somatic mosaic of the modified pattern of 

 both parental cock species. The other members re-manifest the 

 hybrid polymorphism shown in the F 1 generation. 



For the examination of the skins upon which these results 

 are based, I am indebted to the kindness of Mrs. Haig Thomas, 

 who in 1907, at my suggestion, commenced the breeding experi- 

 ments 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 fuller discussion of 

 it can only profitably be undertaken when the paper with the 

 details of results is published. 



