VERMES, FLY LARVAE, AND ECHINODERMS 1 87 



required to complete the course was thus alternately 

 obtained under each of the two conditions. The results 

 obtained with one-third exposed are recorded in Table III; 



TABLE III 



those with three-fourths exposed in Table IV. Each figure 

 in columns three and four in the tables represents the aver- 



TABLE IV 



