38 



A. M. REESE 



cloth, was placed, in a dark room, with its open end fifteen inches 

 from the lens of an arc projection lantern. Observations were 

 taken at five-minute intervals. At this distance the light was, 

 of course, decidedly painful to the human eye. 



The positive response was so marked that only 15 observa- 

 tions were made, which gave 116 facing towards the light to 41 

 facing away; and 105 animals in the near half of the aquarium 

 to 60 in the distant half. The animals facing the light and in 

 the near half were, as a rule, somewhat, though not a great deal, 

 more active than the others. 



It appears, therefore, that the response to white light is about 

 the same whether the source of light be dim daylight or an 

 intense electric arc. 



Experiment IX. — This experiment was to determine the effect 

 of low temperature upon the responses of Diemyctylus to white 

 light at the end of the aquarium. 



TABLE V 



Observations.. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 



Facing light 1 7 2 2 3 5 2 3 



S S- S- A- A- S- S- S- 



Facingdark 10 11 11 4 9 9 8 6 9 8 8 



S- S- S- A- S- S- S- S- A- 



In near end 1 00 76 5 6 74 3 



s S S S S- S- A- S- S- S- S- 



In far end 10 11 11 4 5 6 5 4 7 8 11 



s S S S- S- S S- S A- S- S- S- S- A- 



Observations . . 15 16 17 18 19 20 21 22 23 24 25 26 27 28 

 Facing light. .. 02 4 46243433254 



S A- A- A- A- A- A- A- A- A- 



Facing dark. ..443347774787 4.. 

 A- S A- A- A- A- A- A- A- A- 



In near end... 0000 10 774422222 



S A- A- A- A- A- A- A- A- A- 



In far end 11 11 11 11 14 4 7 7 9 9 9 9 9 



A- S S A- A- A- A- A- A- A- A- A- 



Observations 29 30 31 32 33 34 35 36 37 38 39 40 Totals 



Facing light 4 4 3 5 7 2 4 4 6 3 3 6 122 



A- A- A- A- A- A- A- A- A 



Facing dark 556649765853 231 



A- A- A- A- A- A- A- A- A 



In near end 338567555543 140 



A- A- A- A- A- A- A A- A 



In far end 88265 4 666678 266 



A- A- A A- A- A- A- A- A 



