248 



LEE RAYMOND DICE 



Exp. 17 



Activity on continued exposure to high temperature 

 Time in minutes and seconds required to travel 80 cm. toward a weak light. 



The effect of continued exposure to cold seems to be very 

 irregular. Some individuals show a decrease of speed of travel 

 on continued exposure to a temperature of 15° C, while others 

 show an increase of activity under the same conditions. The 

 results are too uncertain to base any definite conclusions upon. 



Temperature, then, has a very irregular effect on locomotor 

 activity. The most definite fact is that a sudden increase of 

 5 degrees above the normal causes an increase of activity, which 

 persists for a short time. 



LOCOMOTOR ACTIVITY IN RELATION TO THE CHEMICAL 

 CONTENT OF THE WATER 



The chemical content of the water is probably of importance 

 in modifying the rate of locomotion of these animals, but no 

 experiments bearing on this subject have been performed. As 

 the chemical content of the water is subject to very little daily 

 variation this factor cannot be a primary factor affecting diurnal 

 migration although it might have some effect on the seasonal 

 migrations. 



LOCOMOTOR ACTIVITY IN RELATION TO MECHANICAL 



STIMULATION 



Observations show that by strong mechanical stimulation, 

 such as caused by shaking the dish, the locomotor activity is 

 temporarily stopped. This allows the animals to sink downward. 

 On the cessation of the stimulation the activity is, for a short 

 time, greater than before. 



