-28- 





observed^ no dif farenoe in the -accuracy or promptness of the 

 coordination, I have even untwisted tho tube foot again, in its 

 new position, without either disturbing the attachment of the tube 

 foot or the coordination of its felloes* Heedless to say these manip- 

 ulations had to be done with extreme care to avoid stimulations wiiioh 

 might cause retraction* 



Coordination f the tube feet jjnt the active starfish. 



thus far wa have baen discussing coordination in the tube 

 feat of rigid non-looorootor animals* But when a very large number 

 of tube feet are seen in tha suspended specimen, pointing in one 



a 



direction in ^coordinated manner, one is apt to be dealing -vith a star* 

 fish in the active rather than in the rigid state* 



If we suspend a starfish that is active, but not definitely 

 oriented and locomoting in any one direction, we find that the tube 

 feet at the tips and for a centime tar or no re toward the disk are 

 oriented and actively feeling out toward the Up* Proper stimulation 

 of the tube feet at the ends of these rays will elicit the step re* 

 flex in the direction of the tip of the ray* This would indicate that 

 each ray has a tendency to migrate in the direction it points* 



4 



Tand.e.noy. oj each ray to. raipr-atje , to ward jLJ^ .LkJL* 

 That each ray does tend to migrate away from the disk was 

 demonstrated by attaohing five glass tubes or shell vials, large enough 

 to acooaodato the ray, to five floats and presenting these simultaneous- 

 ly to the tips of each of the five rays, in such a way that they could 



each walk nto one of the glass tubes and in so doing pull it back over 

 the ray* When the rays got to the end of the tubes they were seen either 

 to keep on in the same direction or reverse and back out, or part way 

 out* It was raally quite amusing to watch this suspended animal indus- 

 triously 



