MODIFICATIONS IN THE TESTES OF HYBRIDS FROM 

 THE GUINEA AND THE COMMON FOWL^ 



xMICHAEL F. GUYER 



From the Zoological Department, University of Wisconsin 



TWENTY-THREE FIGURES IN TWO PLATES 



The following study is based on material obtained from four 

 guinea-chicken hybrids, the offspring of a yearling black lang- 

 shan cock and a common guinea hen three years old. There were 

 originally five of the hybrids, all male, but during my absence 

 from Cincinnati one died and was not preserved. An account of 

 the general habits and appearance of these fowls together with 

 an analysis of their peculiar color pattern has already been pub- 

 lished.2 



Three of the hybrids were killed at the age of three years, 

 one at the age of six, and the last one died at the age of seven. 

 When five years old the two older ones each developed a pair of 

 sickle feathers in the tail similar to those so characteristic of 

 the ordinary domestic cock, although previous to this time all 

 alike possessed the simpler type of tail feathers seen in the com- 

 mon hen. 



When young the hybrids resembled young guineas in appear- 

 ance except for the fact that the legs were feathered after the 

 manner of the langshan breed of. chickens. These feathers dis- 

 appeared for the most part after a few months, leaving only a 

 few scattering ones on the legs of the adults. All of the hybrid 

 fowls were infertile. Two of them were kept at the Cincinnati 

 Zoological Garden for a number of years in a large inclosure with 



1 Prepared for The Whitman Memorial Volume, but received too late to be 

 included. 



2 Guyer, M. F. : Atavism in guinea-chicken hybrids. Jour. Exp. Zool., vol. 7, 

 1909. Also, La livree du plumage chez les hybrides de pintade et de poule. Bui. 

 Mus. d'hist. nat., Paris, 1909. 



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