72 C. J. CUXNOLLY. 



Beauford, comes to the general conclusion that "adaptive changes 

 in shade occur in the skin of practically all of the different fishes 

 in the region of Beaufort, N. C. ; adaptive changes in color in 

 many, but adaptive changes in pattern in only few." 



When the problem of color discrimination is attacked directly 

 by the method of unlearned responses or by forming food asso- 

 ciations, the factor of light intensity must be the same for all 

 wave-lengths. Hess, who has done most in the field of color 

 responses in animals generally, stoutly denies that conclusive proof 

 has been brought forth for color vision in fishes, and Parsons 

 (1915) accepts Hess's conclusion. 



One benefit of this criticism has been to bring about the use 

 of more precise method in testing the responses of fishes to differ- 

 ent colors. Reeves (1919), however, equated brightness for differ- 

 ent colors and concluded that fishes discriminate light of dif- 

 ferent wave-lengths. On the contrary, Ohashi (1921) concludes 

 that intensity alone is responsible for the different responses in 

 the goldfish and carp when subjected to monochromatic light. 

 As this is the most recent paper that has come to our notice, and 

 as the author arrives at conclusions different from those stated 

 in the present paper, we shall discuss Ohashi's work in detail. 



Ohashi first noticed that goldfish up to three years old were 

 attracted to different colored lights when subjected in turn to 

 these stimuli. In other words they are positively phototropic to 

 all monochromatic lights. 



In the following experiments red and green liquid filters were 

 set in the top of an aquarium equidistant from the ends and the 

 lamp placed midway between them. The fish assembled under 

 the green light which was the brightest for them. When the 

 lamp was adjusted so that the green and red appeared of equal 

 brightness to the observer, the fishes assembled in about equal 

 numbers under each color. From these observations Ohashi con- 

 cludes that no support for the belief that fishes have color vision 

 can be found here. Apart from the fact that the liquid filters ad- 

 mittedly did not give pure monochromatic lights, there is no cer- 

 tainty that the apparent equality of brightness of the two lights 

 to the human eye were likewise of equal brightness to the eyes of 

 the fish. In short, brightness cannot be objectively determined by 



