234 



HARLEY N. GOULD 

 TABLE 5— Continued 



Hermit 5 



Stump 

 Long 



None 

 Long 



Half usual 



length 

 Long . 



Long 



Long 



Adult testis, small 

 Adult testis, large 



Spermatogonia 

 Adult testis, large 



Young testis to sperma- 

 tids 

 Adult testis, large 



Adult testis, large 



Adult testis, large 



Small convoluted tube 

 Seminal vesicle, full of 



sperm 

 Small tube, straight 

 Seminal vesicle, full of 



sperm 

 Small convoluted tube 



Seminal vesicle, full of 



sperm 

 Seminal vesicle, full of 



sperm 

 Seminal vesicle, full • of 



sperm 



The above tables show that the great majority of neuter ani- 

 mals become males when associated with large females; that in 

 the absence of large females, only a very few neuter animals 

 develop male characters, and these few are always found in 

 proximity to somewhat larger individuals. It is to show this 

 fact that the specimens from each hermit shell are listed together 

 in table 6. In no case does the largest individual in a colony 

 ever become a male. 



The stimulus from the larger to the smaller individuals is 

 quantitative. A number of the latter in table 6 have gone 

 through the first stages of male development, but the change is 

 not often complete. The number of sexual products formed is 

 small, motosis rare; the specimens of table 5, on the other hand, 

 nearly all show full male development, both in primary and sec- 



