RELATION OF PLUMAGE TO OVARIAN CONDITION. 173 



in structure from the hen feathers in that the firm web is relatively 

 as well as absolutely narrower. In the feathers of the female the 

 barbules interlock practically to the edge of the feather, making 

 nearly the whole surface into a fairly firm web, but in the male 

 the hackle and saddle feathers have a firm web only in the 

 middle portion, practically the outer half 2 of the barbs being 

 free of barbules and presenting a frayed appearance. These 

 free barbs, together with the longer, pointed loose ends of the 

 feathers cause the relatively rough, stringy texture of the hackle 

 of the cock as compared with the smooth neck of the hen. The 

 loose structure of the feathers in the former case, causing greater 

 diffraction of the light, undoubtedly contributes to a lighter 

 appearance of the hackle, irrespective of the broader white bars 

 under normal conditions. Thus it will be noted that in " Kansas 

 1050," the masculine feathers assumed presumably as a result 

 of the diseased ovarian condition were like cock feathers in 

 respect to shape and structure, but still resembled hen feathers 

 in the matter of width of bars, as shown by comparison with the 

 new hen feathers grown after the new ovarian tissue was intro- 

 duced. 



The above would appear to support Spillman's interpretation 

 of the normally wider white bars in the male as being due to 

 homozygosis for the factor for barring. The form and structure 

 of the feathers would thus be considered as secondary sexual 

 characters dependent on the functioning of the sex gland; 

 barring, however, being dependent directly on the genetic 

 factor, would remain the same, whatever the sexual hormones. 

 Although the failure of the ovary to function properly gave rise 

 to a condition of internal secretion which led to the assumption 



2 Goodale's statement (1918, p. 292) that "the secretion of the ovary is neces- 

 sary for the development of the barbules of the feathers of the dorsal regions 

 since the barbules do not develop along the entire length of the barb in the male 

 or in the capon " seems to be at variance with the above. If he means, as he 

 seems to say in substance, that there are no barbules in the hackle, back, or sad- 

 dle feathers of the male, his observations are certainly different from ours on 

 Barred Plymouth Rocks. It is true that at the tip of the hackle feathers there 

 are no barbules, but farther down they are to be found at the bases of the barbs, 

 while just above where the fluff begins they run out practically to the extremities 

 of the barbs. The statement that they are free on "the outer half " represents 

 the average condition, or that found about midway from the fluff to the tip of 

 the feather. 



