ADJUSTMENT OF FLATFISHES 471 



period, though remaining distinctly paler than dark control speci- 

 mens with which they were compared. They acquired the same 

 shade as the latter, however, after a few hours' exposure to light 

 in the same box. 



17. Experiments with fishes which had been deprived of their 

 sight confirmed the findings of earlier investigators that the unim- 

 paired functioning of at least one eye is necessary for the adjust- 

 ment of the animal to its background. If blinded when in the 

 dark condition, the fishes ordinarily remained dark, though they 

 did not always permanently retain the darkest shade which is 

 displayed by a normal specimen. If blinded when pale, they re- 

 mained pale for about a day, but reverted to a darker condition, 

 representing more nearly the resting state of the chromatophores. 

 An interesting special case was discussed of fishes which had been 

 adapted for a considerable period to a pale background, and after- 

 wards for a brief period to a dark background. These reverted to 

 the pale condition after blinding, though this later gave place once 

 more to the dark state. 



18. Destruction of the sight of one eye (whether the left or the 

 right) had little or no effect upon the chromatic reactions of the 

 majority of specimens of Lophopsetta. 



19. Tactile stimuh, if effective at all, certainly played a 

 quite subordinate part in evoking color changes of an adaptive 

 nature, for the fishes responded as promptly to patterns painted 

 upon the under side of strips of glass as to bottoms of stones and 

 gravel whose complexity could be discerned by touch as well as by 

 sight. 



20. Very decided changes in the markings, as well as the general 

 color-tone of the body were at times called forth by tactile or 

 other non-visual stimuh, and the fish, when swimming, commonly 

 presented a decidedly different aspect from that shown in the rest- 

 ing condition. But such changes as these belong to quite a differ- 

 ent class from those which form the chief subject of the present 

 paper. 



Certain of the facts above summarized, deserve further dis- 

 cussion than was devoted to them in the body of the text. 



