10 INHERITANCE IN POULTRY. 



necessary antecedent of the increased nutrition of the feathers or not can be 

 tested by hybridization, which will show whether or not crest and dome are 

 absolutely correlated. 



5. COLOR OF CREST. In our race this is white, in striking contrast with 

 the rest of the plumage. This color is not necessarily associated with the 

 crest. Wholly gold- spangled, silver- spangled, buff, white, and even black 

 Polish have been created. On the other hand, since normal poultry with the 

 top only of the head white are unknown, it seems probable that the color of 

 the crest has dissociated itself from that of the other parts of the body as an 

 independent unit character. Consequently it is not strange to find a black- 

 crested white breed of Polish (Wright, 1902, p. 448). It will be of interest 

 in our experiments to see how far color and crest are dissociable. 



MATERIAL. 



The mothers in this experiment were partly Polish, partly Minorca. The 

 Polish mothers, Nos. 6 and 7,* were good representatives of their breed, 

 with perfectly black plumage except for the well-developed white crest. 

 The Minorca mothers, Nos. 13 and 14, were also typical birds without trace 

 of mealiness in feathers. 



The father Minorca (No. 12, fig. 4) had a great red comb, 150 mm. long, 

 with seven points, one of which rose to 100 mm. above the level of the 

 head. Its plumage was perfectly black. The paternal Polish (fig. 2) had 

 as representative of the comb a pair of papillae. The crest anteriorly con- 

 tained some black feathers with white base or tip ; next came feathers 75 to 

 loo mm. long, at first largely, then wholly white. At the posterior end of 

 the crest, where it passes into the nape, black gradually makes its appearance 

 until the exclusively black feathers of the neck are reached. White and 

 black do not blend on any feather, but coexist in a particulate fashion. 



RESULTS. 



i. COMB. First generation. Of 88 hybrids between single-combed and 

 Polish-combed all follow a single type, which is, however, very variable. 

 The comb is single anteriorly but bifurcated behind. This may be called 

 the Y-shaped comb. The point of splitting occupies a variety of positions. 

 Usually it lies in the middle third of the whole comb (fig. 8). In some 

 cases, such as Nos. 67 <? (fig. 8), 176?, 350$, and 408?, the splitting 

 point is close to the anterior end, so that the comb is cup-shaped. f In other 

 cases the point of division may be so far posteriad that only the last or the 

 last few serrations are split. Indeed, in one case (No. 324, which died five 

 weeks after hatching) , the comb was apparently perfectly single. I regard 

 this as the last term of the series and suspect that there existed, even in this 



* Bought July i, 1904 ; No. 7 died October 17, 1904. 



tSuch a comb is mentioned by Darwin (1876, Chap. VII) as formed when the two ends 

 of a double comb are cemented together. 



