EXPERIMENTS ON COORDINATION AND RIGHTING 



IN THE STARFISH. 



LEON J. COLE. 



In another paper (Cole, '13) I have presented and discussed 

 the results of a series of experiments on the direction of locomotion 

 of the starfish, Asterias forbesi, with respect to morphological 

 axes, in the absence of directive stimuli. The experiments de- 

 scribed in the present note were incidental to the more complete 

 series just mentioned. They were performed tentatively to test 

 the feasibility of certain lines of investigation which suggested 

 themselves in the course of the other work, but which I have been 

 unable to prosecute further. While they are not extensive 

 enough to serve as a basis for far-reaching conclusions, they 

 nevertheless supplement to some extent the observations of 

 others, and, it is believed, suggest certain lines of research which 

 might be followed up with profit. All of the experiments here 

 described were made in November, 1909, in the animal behavior 

 laboratory of the department of zoology, Sheffield Scientific 

 School of Yale University. 



In the locomotion of the starfish it was found that the "unified 

 impulse" was an important factor, and Jennings ('07) had pre- 

 viously determined the same to be true in the righting reactions 

 of the West Coast starfish, Asterias forreri, which he studied. 

 The establishing of a "unified impulse" toward performing a 

 definite action, such as turning on certain rays, or crawling in a 

 certain direction, implies, of course, coordination. Loeb ('oo) 

 in his book on the "Physiology of the Brain" lays stress on co- 

 ordination in the starfish, though apparently merely as an in- 

 hibiting influence, which prevents the rays not helping in a given 

 reaction from working against its consummation, rather than 

 one which causes them to join actively in bringing it about, that 

 is, by taking part in a "unified impulse" toward that end. In 

 discussing, for example, an experiment which will be mentioned 



later, he says (p. 63): "The experiments seem to indicate that 



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