MENDELIAN EXPERIMENT ON FOWLS. 1 75 



pile fowls, and did not suspect that sex had an important 

 influence on the development of the small amount of colour 

 which I was observing on the white or recessive chicks. In the 

 second generation F,^ I 1 & 2 were both males, and I made a 

 note that the colour on the back of these seemed to get a little 

 deeper as they grew older. F,, II 1 was a white female and 

 F., II 2 a white male. The former was given away at an early 

 age without any record being made of the presence of colovir on 

 its breast ; F^ II 2 was killed on November 8, 1912, when it was 

 about 5 months old, and it is recorded in my notes that it had 

 a tinge of yellow over the back (which includes the dorsal part of 

 the folded wings), but that the colour was very slight. 



In the three broods of F., above described the two whites of 

 tlie first brood were both males, the single white of the second 

 brood was also male, of the live whites in the third brood 

 F.,III 7,8, & 11 were males, 9 & 10 females. On August 25 I 

 first observed with certainty that in the males the colour dis- 

 appeared on tlie thi'oat and breast as it developed on the back 

 and loins, while in the females it continued to increase somewhat 

 both in dej)th and extent on the throat and breast. At this date 

 in F., I 2 c? the brownish colour was much diminished on the 

 breast, and there was quite a deep bufi" on the back and shoulders. 

 In F^ I 3 cJ the colour on the back was not so deep. F^ I 4 c? was 

 killed on July 23, its skin was preserved, and is still in my posses- 

 sion showing a narrow band of rather deep brown extending from 

 the throat to the breast, and scarcely any yellow on the back. At 

 this date this brood was 3| months old, and, as I found the young- 

 fowls were sexually inature at 5 months of age, it is evident that 

 this change of coloiu' in the cocks from the breast to the back 

 takes place at jiuberty, while before that time, in the first adult 

 plumage, the cocks resemble the hens. On the same date the 

 only white in the second brood, F., II 5 cJ , had slight brown on 

 throat a.nd bi'east, rather deep bufli" on back and shoulders. 

 In the third brood which, of course, was younger, tlie cocks 

 showed colour coming on back, and a little still on the breast, 

 except No. 7, which had least colour of all the five whites. The 

 hens 9 & 10 had brown on thioat and no colour on back. 

 In August of the following year I recorded in my notes the fact 

 that of the surviving white, i. e., piles of this generation, the two 

 cocks, F^ I 2 & 3, had buflf colour on the loins but no colour on 

 the bi-east, while the hens, F^ II 9& 10, had brown on the breast, 

 but no colour on back or loins. Two fiirther points are to be 

 noticed in F.^, («) that the amount of colour in the recessives for 

 plumage colour varies in the individuals though present in all, 

 (b) that the maximum amount of colour is distinctly greater 

 than in F„. The total number of F^ chicks hatched was 23, 

 II pile, 12 coloured. 



F^, 1913, and F,, 1914. 

 The first brood of this generation was hatched April 11, but all 



