174 MR. J. T. CUNNINGHAM ON RESULTS OF A 



difference in this pigment, it is not certain that pigment was 

 entirely absent. 



My view concerning this tra.ce of pigment in otherwise white 

 recessives was that the segregation of the colour-character was not 

 complete, but that a trace of the pigment-character passed over 

 to the recessives. If this happened at every generation the 

 amount of pigment should increase, and in order to test this I 

 mated the slightly pigmented recessive with a coloured dominant 

 bird. Tlie birds of F^ were mated thus: 



(1) F.,I Id white X F, I 6$ coloured and 



F.'l 8 2 coloured. 



(2) F^I 2 c? white X F"^I 7$ coloured. 



The two females of the first mating both had light- coloured 

 heads, while No. 7 in the second mating had a black-coloured 

 head. This is an individual difference in the colour of the 

 dominants which is further discussed below. 



F. I was from the second mating shown above, and consisted 

 of four chicks hatched, three " white " or recessive, one coloured. 

 This, of course, shows that the hen parent was heterozygous for 

 colour, as if she had been a pure dominant all the chicks would 

 have been coloured. In this brood I noticed for the first time a 

 peculiarity of the recessive chicks in the down stage. The 

 coloured chicks, as in other black-red breeds, are longitudinally 

 striped : a broad dark stripe runs along the mid-dorsal line, and 

 on each side is a narrower dark lateral stripe which on the head 

 passes through the eye, the intermediate parts and ventral do\Yn 

 being of a lighter brown. In the recessive chicks there are ivhite 

 bands where the darker bands occur in tlie coloured chicks, and 

 yellow down on the rest of the body. As will be seen later, this 

 agrees with the "pile" character in the fledged and adult birds. 



The first brood of F.,, hatched Ma)'- 13, were cai-efully examined 

 on June 23, when they were 6 weeks old and nearly fledged. 

 All three recessives had colour on the throat and breast, but in 

 different degrees : No. 2 had most colour, not only brown colour 

 quite distinct but also black feathers here and there ; No. 3 had 

 less colour, and No. 4 least. At this date thei'e was no colour on 

 the back. 



F3II, hatched about May 23, 1912, consisted of 5 chicks, 



4 coloured, 1 "white" or recessive. This last showed very 

 slight but distinct colour on the throat on June 29, when 



5 weeks old, and no colour on the back. As in Brood I, at 



6 weeks of age, this is the condition when the chicks are first 

 fledged, when they have developed the first adult plumage. 



In brood F^ III, hatched May 28, there were 1 1 chicks, 



6 coloured and 5 white. Of the latter, all except No. 7 showed 

 some brown on throat and breast on July 17, when they were 



7 weeks old. A slight but distinct trace was afterwards seen on 

 the throat of No. 7. 



At this time I kxaew nothing about the colour-characters of 



