STUDIES ON SEX IN CREPIDULA 



117 



Thus, forty-three out of sixty-seven, or about 64 per cent, 

 showed spermatogenetic activity of some sort more than isolated 

 neuters show. Classifying these forty-three with regard to de- 

 gree of male development, we have: fully developed testis, twenty- 

 five; testis containing sperm, but with some missing stages of 

 spermatogenesis, four; testis developed as far as spermatids, 

 eight; spermatogonia and spermatocytes, two; spermatogonia in 

 multiplication period, four. 



The occurrence of incipient female development in some of the 

 specimens will be understood if we assort them all in the order 

 of their size, indicated by the length of the shell in millimeters. 

 This is done in table 2. 



All those having early stages of developing oocytes ('female') 

 are seen to be among the larger animals used for the experiment. 



