AKTIFICIAL PARTHENOGENESIS IN ANNELIDS 677 



developed from one egg ; No. 2 shows two trochophores which 

 are grown together but are otherwise independent. In No. 3 

 we notice the beginning of a common organization, inasmuch 

 as the clear peripheral areas (on the right side) are fused 

 together. In Nos. 4, 5, and 6 the clear areas are almost com- 



1. 



4. 



5. 



6 



7. 



9. 



FIG. 161 



pletely fused together, and only the dark centers remain 

 separated. In No. 7 both eggs are fused . completely and 

 form one giant embryo with one set of organs. Cases like 

 this are very frequent in the material treated with KC1. 

 Nos. 8 and 9 are examples of the fusion of more than two 

 eggs. I have seen four eggs form one giant embryo with one 

 common dark center and one common clear area. Such mon- 

 sters swam, but usually died sooner than the single embryos. 



