ON SOMATIC SEX-CHARACTERS 77 



developed ; the tail contained rather loosely- 

 grouped long sickle feathers ; the spurs stout. 

 The description states that dissection showed no 

 trace of either testicle, and I am informed by Mr. 

 Shattock that there were no grafts. The description 

 ends with the conclusion that the growth of the spurs, 

 and to a certain extent that of the long, curved 

 sickle feathers, is not prevented by castration. With 

 regard to the spurs this result does not agree with 

 that of the German investigators, but it must be 

 remembered that the latter speak only of the re- 

 duction of the spurs, not entire absence. It is im- 

 portant in discussing the effects of castration in 

 cocks to bear in mind the actual course of develop- 

 ment of the secondary sexual characters. When 

 the chicks are first hatched they are in the down : 

 rudimentary combs are present, wattles can scarcely 

 be distinguished, and there is no external difference 

 between the sexes. The ordinary plumage begins 

 to develop immediately after hatching, the primaries 

 of the wings being the first to appear. The feathers 

 are completely developed in about five weeks, 

 and still there is no difference between the sexes. 

 The first sexual difference is the greater size of the 

 combs in the males, and this is quite distinct at the 

 age of six weeks. At nine to ten weeks in black-red 

 fowls, in which the cocks have black breasts and red 

 backs with yellow hackles, the black feathers on the 

 breast and red on the back are gradually develop- 

 ing, both sexes previously having been a dull 

 speckled brown, closely similar to the adult hens. 

 The spurs are the last of the male characters to 

 develop, these at the age of four months being still 

 mere nodules, scarcely, if at all, larger than the 



