1907] Jennings. — BeJtavior of tJie Starfish. 159 



other rays from attaching, so that h pulled the starfish over 

 alone. 



6. This time b AVas forced to take hold, as in the last experi- 

 ment, by preventing other rays from attaching till b had come 

 against the bottom. But this time, as soon as b was well attached, 

 I allowed the other rays their freedom. At once these attached 

 themselves; b released its hold, and swung freely over in the 

 usual Avay, — the turning being mainly done, as usual, by a -{- e. 



7. Prevented others, till b was attached. Then others took 

 hold. This time b kept its hold, but did almost nothing to aid the 

 turning, which was mainly brought about by a. 



8. By preventing others, b finally driven to attach itself and 

 turn the starfish unassisted. 



9. Again b was driven to take hold, by preventing the others. 

 This time b attached itself much more readily than before, taking 

 hold as soon as it was evident that the other rays could not do so. 



10. In the tenth experiment b attached itself almost at once, 

 as soon as the others were prevented. 



Thus these ten lessons of the first day had to be devoted 

 mainly to overcoming the obstinate refusal of b to attach itself. 

 The ninth and tenth experiments seemed to show that the train- 

 ing was having some effect, b acting more readily than before, 

 though still with reluctance. 



In the ten lessons of the second day, the training was again 

 directed toward both b and c, by preventing the other rays from 

 attaching. At first b showed the same disinclination to attach 

 itself, as before; in the first experiment c did the turning alone. 

 The ray e in all these experiments made persistent efforts to 

 attach itself, seeming as strongly bent on playing this role as b 

 was on playing the opposite role. In experiments 2-5, b and c 

 after a time took hold and turned the starfish. But these two 

 rays worked very awkwardlj^ together ; they usually twisted their 

 tips in opposite directions, so that even after they were attached 

 they were unable to turn the starfish. After they had struggled 

 for a time, there was a strong tendency for a to take hold, in 

 such a way as to cooperate with b; this occurred in spite of my 

 efforts to prevent it, in several of the experiments. It is clear 

 that it would be much easier to induce a -\- b to do the turning, 



