-18- 



miniature catapult, a distance of four or five am. on 

 repeating this, the elevation or "angle of fire* was aeen to 

 be such as would entail release of the grain from the diao 

 during the third quarter of the arc that the diso describes 

 in lashing back. Usually, however, in disaster. Asterina etc., 

 the violence of the lashing back is not so sratt, and the 

 release is not very sudden or prompt eo that such a catapulting 

 action is not often seen in these forms* 



a: refj.e^ tft tjhe, aPVffMt SLL 



resistance ^o, Jjhe step* 



The relation of the attaching reflex to the amount of 

 resistance to the step was obtained in the following manner* 

 One of the rays of an Agjfcer^na. was tied by a long thread 

 to a spring recorder which was calibrated to grams and set 

 to writhe on a slowly moving drum. Ihen the animal pulled 

 against the spring, the strength of the pull was recorded as 

 the height of the curve above the base line. Now when the 

 animal had pulled the spring up to various heights, the glass 

 plate on which it was walking was suddenly slid forward - 

 In the direction of locomotion* This resulted in an increased 

 tension on the starfish which was recorded on the drum until 

 this tension became sufficient to cause the animal to release 

 hold on the substrate* The curves got by this method were 

 somewhat as follows: 



1-: the fctfMT' given by the starfish as it walka against 

 tht resistant j>f the spring. s was slid 



