368 



REACTIONS OF DAPHNIA PULEX TO LIGHT AND HEAT. 



Table I. 



TIME (IN SECONDS) REQUIRED BY DAPHNIA NUMBER 1 TO SWIM 50 CM.J WHEN INFLUENCED BY LIGHT ALONE AND 



WHEN INFLUENCED BY LIGHT ACCOMPANIED BY HEAT. 



7 p.m., Dec. 11, 1901. Temperature of Water 20° C. 



Table II. 



THE AVERAGES FOR FIVE SERIES OF EXPERIMENTS LIKE THAT OF TABLE I. EACH COLUMN CONTAINS THE AVERAGES 

 FOR TEN TRIPS MADE BY EACH OF FIVE DAPHNIA (NUMBERS 1 TO 5). 



