STUDIES IN THE LIFE-HISTORY OF F.UGLENA. 353 



formed from the chromatin of the outer nucleus and not from the 

 endosome. 



2. Division of the nucleus is preceded by its migration anteri- 

 orly in the body until it comes into close contact with the lower 

 border of the reservoir. 



3. A chromatoid mass, the kinetic complex, originates from the 

 endosome during the prophase, migrates to the periphery of the 

 nucleus where it divides. The division products pass to opposite 

 sides of the anterior border of the nucleus, in which position they 

 suggest homology with the centroblepharoplasts of Trichomonas. 

 No paradesmose has been detected between them however. 



4. From the kinetic complex a blepharoplast is freed and 

 produces the main branch of a new flagellum. Later, a basal body 

 arises from each blepharoplast, and from it is produced the 

 secondary branch or anchoring root of a flagellum. 



5. The residue from the kinetic complex, after the formation 

 of the blepharoplast, remains on the nuclear membrane until 

 division of the animal is completed and the daughter cells have 

 reorganized. A rhizoplast passes from it to the blepharoplast and 

 in one of the daughter animals an intra-nuclear rhizoplast is seen 

 making connection with the endosome. After reorganization of 

 the daughter animals is completed, the residual mass is cast out 

 into the cytoplasm where it remains during the vegetative stages 

 of the organism as a deeply staining granule surrounded by a 

 lightly staining halo. It usually disappears during the early 

 phases of the next successive mitosis. Its behavior and relation- 

 ship to the motor apparatus suggests a homology with the 

 parabasal body of parasitic flagellates. 



6. The division process is a function of the cell as a whole, being 

 initiated not by the division of a specific body that might be 

 called a centrosome, but rather by simultaneous changes in all 

 parts of the cell. The centroblepharoplast homologue, together 

 with an endobasal body in the endosome seem to constitute the 

 principal dynamic centers. The mass of the endosome seems to 

 constitute a sort of passive framework or spindle for the division 

 process. 



7. The entire motor apparatus of the parent animal, consisting 

 of flagellum, basal body and blepharoplast disappears during 

 division and a new one is built up in each daughter animal. 



