11- 



that are closely analagous* If a starfish IB tipjhtly attached 

 to the side of the aquarium, to gat it off without injury to the 

 tube fget, one has but to stimulate the aides of the tube feet sharply 

 Trith the eds* of seme flat instrument that will slip undor the star- 

 fieh, This stimulation causes the release of the stimulated tube feet 

 and sometimes the release of neighboring tube feat* 



If a starfish be inverted or suspended, when not exhibit- 

 ing a locomotor tendency, and the side of an extended tube foot be 

 touched even v-jry lightly, thire ie an iflwoediate collapse and with* 

 draval of UXQ tube foot* Careful obpervation of the phenomenon 

 leads one to think that it is a reeult, first of the relaxation of 

 the ampulla and second of a contraction of the longitudinal muscula- 

 ture of the tube foot* 



aif a, ra8onq9 J^o. glj^ulAtion o_f. 



If the tube feet show a t'aidency neither to locomotion nor 

 to ttaohraent, this same withdrawal reaction follows the tianilation 

 of the diaV. 



Usually, ho-vorer, Uiere is a tendency toward attachment 

 which does not necessarily interfere with th presence of the with- 

 drawing reaction* This conclusion was reached from a study of the 

 reactions of tube feet to very light suspended objects* A small 

 piece of thin celluloid, suspended by a thread, was brought in con- 

 tact with extended (non-locomotor) tuba feet* The first response* 

 usually was found to be attachment* After tide, dap ending on con- 

 ditions which will be 





