ADAPTIVE CHANGES IN COLOR OF FUNDULUS. 57 



plied that they have the same color sensations as a human being 

 has. 



Several investigators have attacked the problem of color vision 

 more directly by the method of forming food-associations with 

 definite colors and testing fishes for their ability to distinguish 

 these ' from others of equal brightness. Van Rynberk 



( K>CJ(> ) gives a critical survey of the earlier work on color changes 

 in fishes and in animals generally, in which the method of food 

 association, as well as that of instinctive response and simulation 

 of background, have been used in testing color vision. The fol- 

 lowing brief a -count of the more important recent literature in- 

 dicates the results obtained by investigators on color changes in 

 various species. 



/olntnit/ki (1901) using Clicirotiomus larvae as food until 

 tisl - accustomed to it, next presented bits of wool of the 



an<l shape of the larvae but of different colors. The responses 

 to the red were more frequent than to the other colors. He con- 

 cluded that they discriminate colors, but he disregarded the bright 



ti tor. 



liondorlT (1903) maintained that the earlier workers were 

 in error in asserting that fishes assume the color of the back- 

 ground. !>ut he did so on scanty evidence. 



Van l\ \nberk (1906) found that the flatfish, Rhomboidichthys 

 simulates the environment in a striking manner. 



\\aslilnirn and lientley (1906) noted that the horned-dace, 



.notiliis iitrotnaculatiis discriminates red, green and blue. 



Kei-hard i i-joS) concluded from his observations on the re- 

 spo; i" the gray snapper. Lutianus griseus, that it is able to 



riminate colors. 



< ihjections have been raised to the conclusion of investigators 

 up to this time, that there was no certainty as to brightness of 

 light for the eyes of the fishes. 



Bauer i i ' no a) experimenting with Charax puntazzo, Atlicrina 

 hcpSi'tns f... /.'<i.r sal pa and Mugil sp. concludes that " Wie bei 

 norinaleii Men-chen tritt bei Helladaption, zur Unterscheidung 

 der Helli-keit, die Unterscheidung der Farbenwerte." He ob- 

 served aversion to red or " Rotscheti " in Charax and Atherina, 

 and Furkinje's phenomenon in Mogil and 



