PLATE 1 



EXPLANATION OF FIGURES 



1 Dorsal view of a female-producing individual. 



2 Dorsal view of a male-producing individual, with nine male embryos at 

 different stages of development. 



3 Young female at time of birth, viewed from the left side. 



4 Reproductive organs of a young female, dorsal view. 



5 Male embryo, from dorsal view before birth; note the position of the 

 digestive system (d.s.). 



6 Male at time of birth, from right side; compare the final position of the 

 degenerating digestive system with the preceding figure. 



7 to 9 Thin-shelled resting egg, one- to four-cell stage; note the irregular 

 structure of the egg membrane. 



10 and 11 Thick-shelled resting egg; note the porous condition of the inner 

 egg membrane. 



12 Sperm cells in different stages of development. 



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