248 MR, J. T. CUNNINGHAM ON 



Experiment 2. — Japanese Long-tail J X Dorking 5 . 



The second experiment I have to describe was chronologically 

 the earlier, bnt is less complete and less important than that 

 already described. It consisted in crossing a Japanese Long- 

 tailed cock with a Dorking hen. Crosses between the Long- 

 tailed fowls and other breeds have been previously made by 

 C. B. Davenport at the Carnegie Station for Experimental 

 Evolution at Cold Spring Harbour, New York, U.S.A. (' Inher- 

 itance in Poultrj^,' Washington, 1906). In his first experiment 

 Davenport crossed a cock of the Long-tailed breed, which he 

 refers to by its proper Japanese name of Tosa fowl, with a White 

 Cochin Bantam hen. Six F/s were reared, 3 cocks and 3 hens. 

 The males were all of the male Tosa-fowl coloration except that 

 every feather was repeatedly barred with white. The females 

 Avere all of the female Tosa-fowl coloration except that the light 

 shafting was very much broadened. The female Tosa in this case 

 is described as " black mossed with rusty with a straw-coloured 

 shaft to each feather." All three males developed abnormally 

 long middle tail-feathei's, in other words the tail chai-acter of 

 the Tosa was dominant. 



Of the F^ generation 57 individuals were hatched : of these 16 

 were white and 41 pigmented, which approximates to the theo- 

 retical proportion of one in four. But of the 1 6 whites only 5 were 

 without trace of reddish pigment, which occurred on the breast, 

 top of head, and remiges. Davenport draws from this the same 

 conclusion that I have suggested in the case of my cross between 

 Silky and Jungle fowl, namely that segregation is not always 

 perfect, and the gametes from which these whites arose were not 

 pure for the white character. As the F.,'s were immature at the 

 time of publication, the inheritance of the long-tailed character 

 in this generation could not be described. 



With regard to the F/s, Davenport points out that the two 

 sexes, except for the admixture of the white colour, resemble the 

 male and female Tosa fowl respectively, and remarks that from 

 a germ-cell of the male Tosa either a bird coloured like a male 

 Tosa or one coloured like a female Tosa may arise, that the male 

 germ-cells contain the Anlagen not only of the male characteristic 

 but also of the female characteristic. The same result is equally 

 evident in the results of my cross between the male Jungle fowl 

 and the White Silky, the hens in F^ and the coloured ones in 

 F^ showing the coloration and markings of the female Jungle 

 fowl. This conclusion is in opposition to the Mendelian view 

 that the female is heterozygous but the male homozygous, the 

 latter not carrying the female character. Mendelians argue 

 that the effects of castiution in male vertebrates geneiully can 

 be explained as merely the non-appearance of male characters, 

 and they would probably maintain that the coloration of the 

 hens referred to in these cases was merely the absence of the 

 male characters. But it is necessary to distinguish between 



