224 



CHARLES HARLAN ABBOTT 



A generic difference appears in the results. Oniscus was nega- 

 tive, regardless of previous exposure, with the reaction appar- 

 ently uninfluenced by strong light. On the other hand, PorcelUo 

 showed a high degree of positiveness after exposure to Ught. A 

 probable explanation for the two modes in the curve for Por- 

 celHo (after exposure to Ught) is that three out of five indi- 



N umber of 

 1?etfoi\ses 



rr ft Grades of 



Number of 

 ■Responses 



::i^3 



Positive 



10 



Ne^tive 



o Grades of 

 Ne6akTiver>ess 



Figs. 9 and 10 Comparison of reactions after exposure to strong artificial 

 light and to dark. Fig. 9, Oniscus; Fig. 10, PorcelUo rathkei. Numbers on 

 abscissae indicate grades of negativeness shown in figure 2. Numbers on ordi- 

 nates indicate number of responses iri. each of the eight classes. Fig. 9 shows 

 little difference between the responses of Oniscus under the two conditions. 

 Fig. 10 shows that PorcelUo was somewhat positive after exposure to strong 

 light. 



I 



