STUDIES ON HYBRID DUCKS 247 



duck's progeny is left out of consideration there are twelve pig- 

 mented and seven yellow ducklings. In any case there is a con- 

 siderable excess of yellow ducklings, the proportion standing 

 about two pigmented to one yellow, instead of the expected ratio 

 of three to one. 



Later in the season, a Pekin drake was substituted for the hy- 

 brid drake in the second pen. There were seven pigmented and 

 three yellow ducklings. Only one was reared, a male. lie is 

 not included in the table given below. 



A mating was also made between a hybrid male and a Pekin 

 female. Only three ducklings were hatched, two pigmented and 

 one yellow. 



F-i adults. The chief interest in the F2 adults attaches to the 

 pigmented types, which numbered twenty-one individuals, thir- 

 teen females and eight males. The white adults are identical 

 with the Pekins. The distribution among the pigmented adults 

 of the various characters studied are given in tables 1 and 2. 

 But there are also some points which require a more extended 

 treatment. 



Two females (fig. 7) and one male were essentially like the Fi 

 black female, though the male and one of the females had a small 

 amount of white, distributed irregularly on the head and neck. 

 This last female retained her leg band. Her mother proves to 

 be the black Fi female and her father a hybrid male. The black 

 male has no white neck ring, no white primaries and no vermicu- 

 lations. His is the only case in which these characters have 

 been found absent in the male. His head, where not white, is 

 lustrous green as in normal Rouen males. 



The other eighteen individuals, show mostly Rouen characters. 

 In one male the claret of the breast is wanting, its place being 

 taken by iron gray (fig. 8). The speculum of this male is 

 obscured and the under side of the wings pigmented. The rest 

 of the males are not markedly different from the Fi males, except 

 that the width of the neck ring varies considerably. 



Two of the females are much marked with white (fig. 9). The 

 neck ring extends over nearly one-half the neck and reaches up 

 the throat to the lower mandible. There is a large white patch 



