RHEOTAXIS IN ISOPODA 



271 



Table 6 shows the relation between the negative and indefinite 

 rheotactic responses with the rate of efficiency and with shock 

 reactions. Part I gives the data taken when the negative re- 

 sponses were 60 per cent or more of the total reaction. Under 

 these conditions the percentage of positive responses is low but 

 both the efficiency rate and the concussion responses are high. 

 The second part of the table shows the responses when over 60 

 per cent of the total reactions were indefinite. Here again the 

 positive reactions are necessarily few. But it will be noted that 

 the rate of efficiency is low, much lower than when low posi- 

 tiveness was taken as the basis of comparison. The concussion 

 response is almost the same as was shown to accompany high 

 and low positiveness and high and low efficiency. 



TABLE 6 



Showing the responses accompanying high negative and high indefinite rheotactic 



response 



