Reaction to Light and other Points in Behavior of Starfish. 101 



Table 2. 



The results of these 1 5 tests show that the direction of locomotion 

 is quite variable. There is no strong tendency to ascend or descend the 

 incline, although it is true that the descent was made 10 times out of the 

 15. Whatever this may mean, there is surely no strong tendency to 

 climb a floor tilted at 10°; there is no indication of "negative geotro- 

 pism"; they are not "driven there by negative geotropism." 



Light is undoubtedly a very strong stimulus in the tests listed in 

 table I , and one might claim that it resulted in the formation of a habit 

 in which the descent of the incline was associated with strong light 

 entering the open end of the box and that this habit was not overcome 

 by the negative geotropic stimulus. For this reason a series of tests was 

 undertaken like those given in tables i and 2 except that the false bottom 

 was so placed that the top of the incline was at the open end of the appa- 

 ratus and the base at the other. The results of the tests with Hght as a 

 factor are indicated in the following table: 



It will be seen that the starfish moved to the lighted end of the appa- 

 ratus in every case, and in so doing mounted the incline. 



Light was now excluded by covering the apparatus with velvet. 

 The results of the tests were as follows: 



