INFLUENCE OF ENVIRONMENT ON SEX 



237 



in the absence of large females, both in size and in sexual con- 

 dition. This is indicated briefly in tables 7, 8, 9, and 10. 



The experiments on neuter Crepidulas indicate that the 'sex- 

 ually inactive' animals are so because male development cannot 

 take place in the absence of a certain stimulus which proceeds 



TABLE 7 



Neuter Crepidulas transferred to neighborhood of large females; sectioned after 



sixty-seven days 



TABLE 8 



Neuter specimens returned to hermit shells free from other Crepidulas, sectioned 



after sixty-seven days 



TABLE 9 



Neuter Crepidulas transferred to neighborhood of large females; sectioned after 



seventy-five days 



