36* 



as in the derails or tube feet. Mangold (1908). Cowles (1911a), Mast 

 (1911), and others adhered to this view more or loss explicitly. The 

 ingenious experiments of Plesner (1913) hare made it seem quite proba- 

 ble that the starfish responds to direct illumination of the dermis and 

 that the eye spot receiver stimulation from distant areas of Hoht or 

 shadow to which tUa starfish res onds also* This results in a very 

 puzzling aggregate of reactions as the controversy attests* 



away from the side that is in a state of sub or super optimal illumina- 

 tion, 



Significance of the negative b r ehavipr ojf the, jj-golatod ray u , 



The negative behavior of the isolated ray, is, as has been 



long inown, much less definite than that of the whole animal* Romanes 



and Kwart ( 1831, p. 1356) state that "Single rays detached from the 



organism crawl" sometimes a^ay from injuries, but they do not invar- 



A 



iably or ovan generally seek to escape from the latter as is so certain 

 to be the ciae with the entire animals"* In confirming this it was 

 found that a migrating ray which had been isolated, wffttld give Very 

 irregular responses to stimuli which would cause negative behavior in a 

 normal animal* A negative response to pinching or prodding is the ex- 

 ception, -rather than the rule in the behavior of isolated rays* This la 

 to be exp30t3d in the light of what h*s been said about the nature of 

 the negative response because the "rays opposite the stimulus" are not 

 there to unfailingly initiate/ a migration away from the stimulus* 



_ . ^ 



BSHAVIQR pv TjB STARFISH 1H5W UKDSH Tflft ISFLUI2TCS 0? 



IMPULSS 



Having studied the factors which govern the formation of the 

 "unified" impulse we shall now turn our attention to the behavior of an 

 animal under the influence of this physiological state, first taking 

 up the factors which cause a change in the "physiological anterior" 

 and factors which cause a change in the direction of locomotion of the 

 starfish by a rotation of the body as a whole without changing the 

 anterior rays. 



the factors which cause a change in the physiological anterior 



