LIGHT OF DIFFERENT WAVE-LENGTHS BY FISH 77 



Goldsmith (1914) in a most suggestive paper gives the 

 results of a study of the perception and memory of colored 

 objects by fish. Her work shows differences in this respect 

 in the various species used. While Gobius avoided red, 

 the stickle-back came to rest over red and approached the 

 red objects presented. 



Freytag (1914) reports work to determine whether fish 

 become colored like their surroundings. The fish were 

 usually placed for a few hours in a glass dish above a given 

 background. Twenty-four hours seems to be the maxi- 

 mum time. He finds no proof for color vision in the Phox- 

 inus laevis used. The fact that there is in his specimens a 

 tendency to match the background in brightness leaves 

 one in doubt as to whether with as much time for color 

 adaptation as was allowed by Mast for flounders these 

 fish would not also have shown consistent color changes. 



Mast (1916) has published evidence of color vision and 

 of the avoidance of red by fish. In experiments on change 

 of color to conform to background, he used red, yellow, 

 green and blue paints. He had boxes painted half with 

 one color and half with another one of the four colors used, 

 so that all possible pairs of these colors were provided. 

 Fish (flounders, Paralichthys and Amylopsetia) were al- 

 lowed to become adapted for six weeks or more, to each 

 of these colors in boxes painted of one color. Colored 

 photographs show that they became colored like the back- 

 ground. They were then released above the dividing line 

 of a two-colored box in order to see toward which half 

 they would swim. It appears from an examination of 

 Mast's data that fish adapted to blue showed 88 per cent 

 of blue choices, those adapted to green 70 per cent of green 

 choices, but those kept in the red box and then released in 

 the two-colored boxes went to the red in only 26 per cent 

 of the choices. Of the 120 times when red and blue were the 

 pair of colors presented to the red-adapted fish, it went 

 but five times to the red. This record, given by Mast, 

 of natural differential response in avoiding red has added 

 value from the fact that his experiments were not per- 

 formed for the purpose of testing the existence of a differ- 

 ential response to that color. 



