'J 1 8 Williams, Color in Relation to Inheritance. \*Oa 



may supply a hint or two, but these will not be dwelt upon just 

 here. 



To conclude, we may affirm, that beyond doubt there was a 

 marked change of color in the feathers of my Owl from gray to 

 a reddish cast ; that this was not concurrent with any pronounced 

 feather loss (ptosochromatism) ; that it was undoubtedly, as seen 

 at the present, influenced partly, if not in whole, by an unnatural 

 diet (liver and kidney); and that in consequence it is an example 

 of abnormal aptosochromatisin. 



It appeared from the macroscopic nature of the change that 

 repigmentation was forcibly present but to my misfortune, 

 being unable to further investigate this, I will leave it open to the 

 judgment of my readers. 



THE COLOR OF CERTAIN BIRDS, IN RELATION 

 TO INHERITANCE. 



BY I. BICKERTON WILLIAMS, F. Z. S. 



There are two powerful tendencies whose working has, appar- 

 ently, determined, to a large extent, the differences and the 

 resemblances in the color of birds, as well as many others of their 

 characters. 



These are 'Variation,' on the one hand, tending to produce 

 desirable and necessary changes through the action of natural 

 selection; and 'Inheritance,' on the other, tending to preserve 

 and hand down those forms and qualities that were useful and 

 beneficial to 'former generations, and which, even now, are not 

 injurious. 



In the determination of color, sometimes one of these tenden- 

 cies seems to have got the upper hand, and sometimes the other. 

 There are certain bird groups that display so many different styles 

 and colors, that, like modern fashions, one might imagine they 

 had been adopted merely for the sake of variety ; while, in other 

 groups, some ancient style of plumage and color appears to have 



