314 Proceedings of the Royal Irish Academy. 



may but represent tte external symxDtoms of a varying metabolism. 

 They may be, as I have elsewhere suggested, primarily but the 

 symptoms of a pathological or quasi-pathological condition, the 

 importance of which to the organism must quite OTershadow any 

 external applications f':r ornament or protection. 



In conclusion, I submit that my hypothesis, although it may not 

 explain the minutige of each individual case, throws a distinct Kght on 

 the phenomena of winter whitening, and through it of animal coloura- 

 tion as a whole. It also illustrates the possibility in nature that 

 characters having a definite physiological or primary meaning may be 

 found useful for some quite secondary external purpose. 



