AMONG SOME or THE LOWER ANIMALS. 213 



In the second experiment, tlie numbers after tlie first hour 

 were 32 under tlie yellow, 10 under tlie red, and 11 under the 

 blue. After fiye observations, during which 86 were added to 

 the yellow division, 188 to the red, and 180 to the blue, the 

 numbers were — under the yellow 35, red 11, blue 15. 



In the third experiment, the numbers after half an hour were 

 40 under the yellow, 14 under the red, and 8 under the blue. 

 After five observations, during which 73 were added to the yellow, 

 186 to the red, and 206 to the blue, there were — under the yellow 

 43, under the red 15, and under the blue 7. 



In the fourth experiment, the numbers, after half an hour, were 

 38 under the yellow, 15 under the red, and 14 under the blue. 

 After six observations, during which 89 were added to the yellow, 

 166 to the red, and 176 to the blue, the numbers were — under the 

 yellow 30, under the red 19, and under the blue 10. 



In the fifth experiment the numbers, after half an hour, were 

 40 under the j^ellow, 14 under the red, and 13 under the blue. 

 After 7 observations, during which 86 were added to the yellow, 

 263 to the red, and 272 to the blue, the numbers were — under the 

 yellow 38, under the red 13, and under the blue 15. 



YeUow. Eed. Blue. 

 1st observation. 



At the beginning .... 41 16 15 



„ end 37 15 6 



2nd observation. 



At the beginning .... 32 10 11 



„ end 35 11 15 



3rd observation. 



At the beginning .... 40 14 8 



„ end 43 15 7 



4th observation. 



At the beginning .... 38 15 14 



„ end 30 19 iC 



5th observation. 



At the beginning .... 40 14 13 



„ end 38 13 15 



I conclude, then, that the presence of some of the Daphnias in 

 the red, blue, and violet is more or less due to the causes above 

 indicated, and not to any individual preference for those colors. 



My experiments, I think, show that, while the Daphnias 

 prefer light to darkness, there is a certain maximum of brilliancy 

 beyond which the light becomes inconveniently bright to them, and 

 that they can distinguish between light of different wave-lengths. 



