-5- 



only in the looomoto^or resting (active but unoriented) 

 state. 



In Asterini the physio logical states are not wall 

 differentiated. The animal dees not attach tightly though 

 it does become rather rigid and inactive. he looomotor 



^,yV>XwW 



state is olearp^lthouEh in the unoriented state one often 



tb 

 sees the snimil make lurches, as if 4&e orawl in this and then 



in that direction without actually doing so* 



The other starfish observed seem to present different 



physiclp ioal states .-uore or less analogous to those described 



for Pisaater. 



In the folio-fine pages we shall discuss the responses 



of the tube feet as individual organs, their coordination 



among themselves, and the relation of these movements to the 



c.-ordinition of locomotion and righting* 



ft* 4 sipofrg xuas POOT 



The tube foot of a nomnl starfish may exhibit the follow* 

 ing responses, .tiich vary, as we sJnll see, with the physio* 

 logical state of the aniaal: (1) extenaion ; (2) attaohing(S) 

 withdrawal, (4) step reflex* 



3HTBHSION 



-Extension of the tube feet is best seen in the active 

 starfish upon the absence of those mtimulations which normally 

 cause a withdrawal of the tube foot or complicate its extension 

 by inducing the activities of attaching or ""stepping." 



70 study the factors which govern simple extension of the 

 tube feet it is necessary then to invert the animal on its 

 abofal side, or better yet to suspend it freely in the water. Thus 

 are avoided the disturbance of contact stimulation. 



