114 ANNALS NEW YORK ACADEMY OF SCIENCES 



With the intention of examining further the report cited by Spillman, 

 and of testing, by further combinations, the offspring of the first genera- 

 tion, we began the following experiments in 1909, using Barred Ply- 

 mouth Eock and Langshan fowls. We undertook also to extend the 

 experiment by using another breed of barred poultry, the American 

 Dominiques. 1 It is currently stated that Dominiques (but not American 

 Dominiques) occur in the ancestry of Plymouth Eocks. We wished to 

 see whether "sex-limited" or "sex-linked" inheritance is found also in 

 this other race. Plymouth Eock-Langshan crosses have been made by 

 one of us (Goodale) on the experimental farm of Mr. B. B. Horton, to 

 whom we are under many obligations for opportunities to carry on the 

 work. The Dominique-Langshan crosses were made by the other (Mor- 

 gan) at Woods Hole during the summers of 1910-11. In the meanwhile, 

 Pearl and Surface (1910) have described the results of a cross (and its 

 reciprocal) between Barred Eock and Cornish Game. Goodale (1909, 

 1910) has given briefly some of the results obtained when Barred Eocks 

 are mated (reciprocally) with Buff Eocks and when Brown Leghorns 

 are mated with White Eocks. Hadley (1910) has called attention to 

 similar results published by Cushman in 1893. Davenport (1906, 1909) 

 has described various crosses to one of which certainly (White Cochin by 

 Tosa) and to the others less clearly may be given the same interpretation 

 that applies to the results described in the other papers mentioned above. 

 These crosses all involve the barring factor. Sex-linked inheritance of 

 other factors in poultry has been noted, not only by several of the above 

 writers, but also by Hagedoorn (1909), Sturtevant (1911) and Bateson 

 and Punnett (1908). To Bateson and Punnett is due the explanation 

 of the phenomena of sex-linked inheritance for poultry. Mor.e recently 

 (1911) these authors have published a complete account of the inherit- 

 ance of a factor derived from Brown Leghorns which affects the patency 

 of the type of pigmentation characteristic of the Silky fowl. 



Crosses between Plymouth Eocks and Langshans 



Description of the Breeds. — For a detailed description of the breeds 

 under consideration, reference must be made to the various standard 

 works on poultry. In this paper, only a very brief statement of the 

 chief characteristics involved in the cross will be given. 



The Black Langshans (Plate XVII, figs. 2 and 3, and Plate XVIII, 

 fig. 1) are uniformly black, varying somewhat in brilliancy in different 

 regions of the body. The shanks, too, are dull black ; the bottoms of the 



J The American Dominique is a younger breed than the Barred Plymouth Rock. 



