Plate 22. 



Stages in the development of the parasitic generation of Pegantha smaragdina, sp. nov. 



All figures magnified 1600 diameters. 

 Specimens fixed in formol ; stained in Delafield's haematoxylin. 

 Figs. 1-6. Amoeboid cells from the mesogloea, near the aboral gastric wall, close to the 



margin of the gastric cavity. 

 Fig. 5. An amoeboid cell in process of amitotic division. 

 Fig. 6. Amoeboid cell in contact vi^ith the endoderm (en). 

 Fig. 7. Mitosis in endoderm cell. 

 Figs. 8, 9. Mitosis in amoeboid cells ; metaphase. 

 Figs. 10, 11. Two amoeboid cells in contact. This is the phenomenon which led Metsch- 



nikoff to believe that one cell might engulf another. 

 Fig. 12. Youngest undoubted stage in development of the larva. The embryo consists 



of two cells, one, the nurse (n.ce), enclosing the other. 

 Fig. 13. A slightly later stage. The nucleus of the nurse cell (n.n) has divided amitoti- 



cally. The inner cell, the future embryo, is in the metaphase of mitosis. 

 Fig. 14. Still later stage. The embryo is in the two-cell stage. The nurse cell in this 

 specimen has only one nucleus. 



