DIRECTION OF LOCOMOTION OF THE STARFISH 

 (ASTERIAS FORBESI)! 



LEON J. COLE 



College of Agriculture, Universihj of Wisconsin, Madison, Wis. 



NINE FIGURES 



CONTENTS 



I. Introduction 1 



n. Material and methods 3 



III. Method of locomotion ^ 



IV. Experimental results 8 



1. Direction of locomotion 8 



2. Relation of direction of locomotion to length of arm 12 



3. Persistence of the impulse — 16 



4. Rotation of the impulse 17 



5. Relation of arms used in righting to direction of locomotion 19 



V. Comparison with other echinoderms 23 



1. Preyer's experiments on starfishes 24 



2. Echinoids and other echinoderms 26 



VI. Concluding discussion 28 



VII. Summary 31 



Literature cited ^1 



I. INTRODUCTION 



Jennings ('07), in his comprehensive paper on the behavior 

 of the starfish Asterias forreri de Loriol, devotes considerable 

 attention to the righting reactions of this animal. One of the 

 results stated in this connection is as follows (loc. cit., p. 144): 



There is for some reason a general tendency, seen in all the speci- 

 mens, to use certain definite rays for the pulling over. A strong tend- 

 ency is evident toward using the rays lying close to the madreporic 



1 For a preliminary statement of some of the results detailed in the present 



paper, see Cole '10. 



1 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 14, NO. 1 

 JANUARY, 1913 



