230 EVIDENCE THAT DAPHNIAS 



covered part and replaced them with an equal number 

 of fresh ones. If, then, some Daphnias preferred red or 

 blue, I ought thus to eliminate the others, and gradually 

 to get together fifty agreeing in this taste. This, how- 

 ever, was not the case. In the first experiment, an hour 

 after the Daphnias were placed in the vessels there 

 were, out of 50, -tl under the yellow, 16 under the red, 

 and 15 under the blue, the remaining 9, 34, and 35 

 respectively being in the uncovered portion-^. These, 

 then, I removed and replaced by others. After doing 

 this five times, and thus adding 80 in the yellow division, 

 187 in the red, and 209 in the blue, the numbers were 37 

 under the yellow, 15 under the red, and 6 under the blue. 



In the second experiment, the numbers alter the 

 first hour were 32 under the yellow, 10 under the red, 

 and 11 under the blue. Aft r five observations, durino' 

 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 jellow, 14 under the red, and 8 

 under the blue. After five observations, during which 

 73 were added to the yellow, 1S6 to the red, aud 200 

 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 

 liour 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 yellow, 14 under the red, and 



