Bancroft. — Distaplia occidentals. 



PLATE 3. 



Fig. 13. Oogonium from an adult zooid. The test cells are just forming. 



Fig. 14. Part of the wall of the ovary, showing an ovum projecting beyond the 



ovary and just beginning to form a stalk. 

 Fig. 15. Same; ovum is much older, with a well -formed stalk containing differ- 

 entiated stalk tissue. 

 Fig. 16. Whole preparation of ovum, showing maximum size attained in the 



ovary. Bausch & Lomb 2 in., Zeiss 2 ; X 40. 

 Fig. 17. Same; ovum partly extruded from ovary into oviduct. Bausch & Lomb 



2 in., Zeiss 2 ; X 40. 

 Fig. 18. Same; ovum has not quite completely entered the pouch. Bausch & 



Lomb 2 in., Zeiss 2 ; X 40. 

 Fig. 19. Section through a medium-sized ovum, showing bends in the nuclear 



membrane and cytoplasmic vacuoles. 

 Fig. 20. Germinative vesicle of an ovum in a medium-sized bud. 

 Fig. 21. Ovum in a medium-sized bud. 

 Fig. 22. Young ovum from an old bud. 

 Fig. 23. Same ; ovum a little older. 

 Fig. 24. Follicle and periphery of an ovum a little larger than that in Fig. 13. 



Test cells are being formed. 

 Fig. 25. Test cell and follicle cell from the same ovum. 

 Fig. 26. Follicle and test cells of a medium-sized ovum. A much smaller ovum 



is enclosed within the thickness of the follicle. 



