-79- 



7/ Coordination in the active but unoriented starfish involves 

 orientation of tne distal tube feet, toward the tips of the 

 rays. With the rays on separate substrates, thi- -jncy 



results in their -valuing in five dif fe^snt directions, ^nder 

 pathological conditions this ten enoy results in autotumy. 

 Orientation of the tuoe feet is not referable to a simple nerve 

 net as is Coordination in extension and -et-action but to a more 



complicated and possibly an independent mechanism. 



>L^ 



8/ The unified impulse is formed (1) "by the spreading bink of 

 the oriented stale in tne tip of one of the r^ys. Various factors 

 may cause tne relative increase 'vhi.Cn results in its spread over 

 t.ie rast of t e animal (2) by the spreading baoV and fusion of 

 Reoriented states in adjacent rays. (3) By direct orientation 

 of tne tuba feet from exits, tion of the dermal nerve n;t or the 

 tube feat, themselves* 



9/ .Behavior of the oriented animal is conditioned by all of 

 the above factors acting at the same time and in nice balance 

 against each other. In the actively migr*ting starfish the tube 

 feet are all oriented in tii3 same direction. 



10/ The unified impulse^; (l) in some types of righting reaction, 



(2) in the Deviation reaction, (3) in the looomotor starfish with 



**s. 

 a curved lateral arm, is broken up into areas in Wjiioh the tube feet 



are oriented in different directions. This is highly adaptive. A 

 possible -hysiolosical explanation is saen in th3 traction on the 

 tube feat resulting irom the movement of the rays over the sub- 

 strate. Evidence for tuis hypothesis is -rawn from (1) Ueurotoraized 

 starfish (2) starfish wit,, the rays placed on separate substrates; 



(3) the mechanics of the deviation reaction. 



ll/ The righting reaction is a phase of ordinary locomotion 



