26 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



[In other experiments Conant shows that it is not the stimulus 

 of walking that causes them to swim when carried into the room, 

 for they would not swim when he walked with them on the porch. 

 Also, he shows how they may change, some swimming, others not, 

 when left for some time in any one place.] 



7. In a tumbler were two pulsating very vigorously. Placed in 

 the bright sunlight, very little breeze now and then, they showed no 

 change whatever. 



8. Some in a jar were covered with a black coat. The coat was 

 taken off, and almost immediately they stopped pulsating, or pulsated 

 but feebly, and sank to the bottom. The coat was put on again with 

 one part near the bottom of the jar exposed. Almost at once, the 

 animals, which were quite motionless, pulsating but little, resumed 

 pulsation, which became more and more vigorous, and quickly swam 

 to the top again. It seems plainly to be a reaction to light. [Such 

 experiments as this were repeated at different times with very like 

 results.] 



9. A bucket with several bobbing actively on the surface was set 

 out in a smart shower, and the animals continued bobbing on the 

 surface as before. I could not see that they made the slightest 

 attempt to go below. 



There can be no doubt but that there is an individual difference 

 in sensitiveness to the reaction of light after darkness. E. g., I just 

 removed the coat from a dish with four in it ; one went to the bottom 

 at once, another presently, a third remained active at the surface, 

 the fourth when noticed was on the bottom. 



There is also a difference in the length of time they stay on the 

 bottom as well as in the quickness in the response to light. Some 

 recover very quickly, should say in less than a minute, and at once 

 become very active. Some stay for a long time and only resume 

 activity upon the coat being placed over them. Perhaps this explains 

 some of the observations in Experiment 1. 



Sensory Clubs. 10. All four concretions were removed and the 

 animal stood the operation well. It swam more restlessly, however, 

 than others did in the same surroundings. It seemed at first to show 

 a trace of loss of sense-perception. It swam up, and down again, 

 more changeable than those intact, which stay rather more constantly 

 either on the bottom or at the surface. This may, however, have been 



