242 



CHARLES HARLAN ABBOTT 



TABLE 12 



Comparison of reactions of Oniscus after delay when light is continuous and when 

 light is extinguished after 5 seconds. Intensity, 12.79 CM. 



Whole number of delays in response con- 

 sidered 



Responses after delay 



Failures to respond after delay 



Average interval before delayed response 



Average angle of negativeness in delayed 

 response 



WITH CONTINUOUS 

 LIGHT 



84 



58 (69 per cent) 



26 



3L7 seconds 



76.50° 



WITHOUT CONTINUOUS 

 LIGHT j ..,i6iji 



80 



50 (62.5 per cent) 



30 



34.6 seconds 



49.50° 



Number o|- 



Responses 



GrftdeS of 



Nec^aTivCness 



Negative 



Fig. 14 Comparison of responses of Oniscus in instances of delayed response, 

 when the light is turned off after five seconds (solid line) and when the light is 

 continued (broken line). Numbers on abscissa indicate grades of negativeness 

 in figure 2. Numbers on ordinate indicate number of each type of response. 

 Shows practically no response after delay unless the light is continued. 



light was continuous is nearly typical for the ordinary negative 

 reaction of an animal facing the light. (Compare with A in 

 figs. 6 and 7.) This set of responses after delay has a larger 

 proportion of positive responses than was shown in figures 6 

 and 7, but it forms essentially the same type of curve and is quite 

 different from the results when the light was turned off. The 

 same difference is shown, though less noticeably, in table 12, 

 where the angles of negativeness differ by 27°. 



