ALICE M. BORING AND T. H. MORGAN 



129 



are the cells whose secretion suppresses in the hen and in the Sebright 

 male the characteristic cock-feathering. 



In support of this conclusion it may be pointed out that one of us 

 has recently shown that complete removal of the testes from the male 

 Sebright causes him to assume the plumage of the ordinary cock.^ 

 The result is the same as removal of the ovary from the hen (Good- 



LuTear cells 



'■^•■•V^-Xfv- 



Fig. 3. Several groups of lutear cells in the regenerated testis of a Sebright 

 male. 



ale), and theoretically due in both cases to the removal of the lutear 

 cells. The complete demonstration of the above conclusion should 

 be obtained by implanting in an ovariotomized hen pieces of the 

 testes of a Sebright male, producing thereby the same effect as that 

 produced by the presence of her own ovary. 



^ Castration of the ordinary cock does not change the character of his 

 plumage. 



