-45- 



X have in fact been unable to manipulate the starfish so 

 as to exert a steady pull in any one direction for any length of time 

 without causing the tube feet to attach and hold on, a tendency -which 

 then spread to other tube feat and inhibited any coordinated impulse 

 that mi/7;ht havo resulted. Later, moraover, on certain occasions they 

 have been observed to retract and be entirely inactive, 



I h-jve manipulated the animals by slowly moving the sub- 

 strates on ^hioh ona or two rays were ?ra Iking and have manipulated 

 tha.-i by means of nourotoiaized or anaesthetized rays but h^ve not been 

 able to do 30 T vi th enough dalicaoy to avoid stimulating the tube feet 

 to become attached or completely retraotad, I ara inolinad, therefore, 

 to consider those results irrelevant rather than evidence against the 

 possibility thit the substrate may have an orienting influence upon 



the tube feet. 



W**t \?'i 



IS vi dance frog neurotomizad animals. 



I f the substrate can orient the tube feet by exerting a 

 directive puXl on them through the movement! of the animal, ^e might 

 expect to find that if one of the posterior arms of a loconotor star* 

 fish -?ere neurotoiaized, tnere might be coordination brough about by 

 the factor in question* Several experiments were performed with it 

 in view to teat this hypothesis, the results of which were complicated 

 by the marked tendency in the injured animals to attach closely and 

 firmly to the substrate. 



The operation was performed on a large, active Pyonopodia* 

 At first the tube feet on the injured ana attached but the movement 

 of the animal wrenched the tube feet loose leaving in one or two caae 

 the dis." affixed to the substrate* As the locomotion continued the 

 tube I3et stuck less and less 



