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T. H. MORGAN. 



doubtedly have been hen-feathered if it had not been castrated. 

 Further details concerning these two birds are seen in the photo- 

 graphs of the birds and of their feathers. The appearance of 

 the castrated "younger" bird on September 9, may be gathered 

 from Fig. i, A. 



He was obviously becoming cock-feathered at this time, but 

 the change was not as great as it became later. The juvenile 

 feathers present on June 16 (at the time of operation,) are shown 

 in Fig. 2, a, b, c, d. The changes that had taken place by Novem- 



FIG. 3. a, b, c, d. feathers of adult hen-feathered Campine (Fig. 8, A), and 

 a 1 , & 1 , c 1 , rf 1 , those of Fig. i, C, March 13. 



ber 12, are shown in the photograph of the bird (Fig. i, B) and 

 in the pictures of the feathers (Fig. 2, a 1 , b 1 , c 1 , d 1 .) The last 

 picture of this bird was taken April 16, 1920 (Fig. i, C). The 

 picture shows the long, white neck-feathers, that are almost 

 white. The long, white saddle feathers are also well shown in 

 the photograph. The tail coverts and the sickle feathers are very 

 long and the upper ones are black. Later the sickles became even 

 longer. The white shoulder feathers can be seen through the 

 neck hackles. The details of the feathers are better shown in 



