ADAPTIVE CHANGES IN COLOR OF FUNDULUS. 59 



black environment represented by a box lined with black paper, 

 were of a dark >hade ; while those placed in absolute darkness 

 were, contrary to what one would expect, of a light shade. It 

 wa- al-o observed that when temporarily blinded they did not 

 exhibit any change in the various environments, showing that the 

 action "f light was not a direct one. but indirect, the eye being 

 the receptor. 



A> a -tartin- point these experiments were repeated and uni- 

 form i eeing with these were obtained. 



A tot was now made to determine the effect of different colored 

 backgrounds on the shade of Fundithts. Four square boxes were 

 lined each with a differently colored paper, one side being left open 

 fur the entrance of light. The colored papers matched tl 

 named in brackets as given in Ridgway's " Color Standards and 



lor Nomenclature." The first was lined with light yellow 



1 paper ("Lemon yellow. PI. IV.. No. 23); the second with red 



pal red. PI. I.. No. 3, i) ; the third with green (Scheele's 



L^reen, PI. 6., No. 33, i) ; and the fourth with blue ( Bradley 's blue, 



PI. 4. No. 50- 



l'i-lies were first made to assume the light shade by being 

 lei't for several days in a white glaxed earthenware vessel in the 

 laboratory. From this stock they were selected for experiment. 

 Four specimens were placed in each of four battery jars filled 

 with water to a depth of 10 cm. and the jars placed in the colored 

 es. The boxes were illuminated by a white Mazda lamp (100 

 watts i placed at a distance of 60 cm. from the jars. For pur- 

 p"-es of direct comparison all combinations of colored boxes taken 

 two at a time were made, the two boxes and incandescent lamps 

 being screened off from each other. The experiments were all 

 carried out in a large dark room, so that the fishes in each box 

 e under the same environmental conditions, except difference 

 in background. The tests were each of 24-hours duration. 



It w.i- found after repeated experiments that the specimens 

 from each colored background showed a distinct shade. When 

 compared mi a white ground in diffuse daylight, the specimens in 

 the yellow box showed the lightest shade, those in the red box 

 came next, the specimens in the green box were darker and in 

 bine darkest. No change of color was noticed. All four were 



