PHYSIOLOGICAL DEGENERATION liST OPALINA. 645 



Fig. 5. — A cyst-wall has been formed, and the two solid chromatin nuclei 

 are applied to one another. 



Fig. 6. — Specimen showing a still later stage in the fusion of the nuclei. 

 A thick, soft cyst has been formed. 



Fig. 7. — Fresh preparation in which a cyst has been formed and the nucleus 

 has broken up into chromidia. 



Fig. 8. — Atrichous form in fresh condition, showing nucleus with peri- 

 pherally placed chromatin masses (annular in optical section). 



Fig. 9. — Large multinucleate atrichous form breaking up to form smaller 

 ones. At least one nucleus is dividing. 



Fig. 10. — An individual in the act of forming buds. Small blister-like 

 nuclei are budded off, and the cytoplasm has become constricted round one of 

 these, forming a complete bud. 



Fig. 11. — Similar form, in which nucleus is seen in optical section. One 

 nucleus has been completely separated off, and another is almost so. 



Fig. 12. — Association of eleven typical atrichous forms. None of these 

 have as yet formed chromidia, tiiough one appears to be enucleate. 



