POSSIBLE VALUE OF EYE COLORATION 551 



If the phenomenon is really as striking as all that, it may perhaps be 

 legitimately classed as a 'warning display'. 



Fishes, despite their extensive dermal changes, show little or no 

 change in iris coloration with illumination. Trautman has noted, how- 

 ever, that in northern spotted bass (Micropterus p. punctulatus) dying 

 of anoxia, all dark coloration fades from the iris, leaving it red and 

 silvery. Ouradnik, while making color-photographs of narcotized rock 

 bass, accidentally found that the eye would turn red in response to elec- 

 tric shock. Apparently noxious stimuli may contract the melanophores of 

 fish irides, allowing other chromatophores to take charge of the color- 

 ation. But such phenomena cannot very well have any ecological signific- 

 ance. 



