STUDIES IN THE LIFE-HISTORY OF EUGLENA. 351 



He first regarded it as a centrosome but because of its appearance 

 in different parts of the cell, and because it appeared to persist 

 after division was completed, he did not commit himself to this 

 interpretation. 



Keuten (1895) likewise found bodies lying near the nucleus 

 during the division of Euglena viridis, which persisted after 

 division and could be found surrounded by a halo in various 

 parts of the cell in the vegetative condition. He did not think 

 these were centrosomes nor in any way related to the division 

 phenomena. 



Haase (1910), in Euglena sanguined, traces the flagellum 

 from the lower border of the reservoir into the cytoplasm where 

 she finds and figures both branches ending in a basal body 

 (diplosome?). 



Tschenzoff (1916) describes granules in the cytoplasm of 

 Euglena viridis but explains them as artifacts resulting from his 

 methods of killing. 



One is led to believe from the above descriptions that the 

 granule observed in the different species mentioned is the same as 

 that traced through its entire development in Euglena agilis. It 

 has been seen to arise from the endosome, pass to the periphery 

 of the nucleus, divide into two equal daughter granules which pass 

 to opposite of the nucleus. In this position the granules seem to 

 be homologous to the centro-blepharoplasts as described by 

 Kofoid. In the early prophase stages each granule produces a 

 blepharoplast which passes to the border of the reservoir and later 

 gives rise to the main branch of the flagellum. The chromatoid 

 residue left on the nuclear membrane increases in size during the 

 telophase, and during the quiescent period when the nucleus 

 migrates posteriorly to its original position in the cell, breaks away 

 from the nuclear membrane, becomes surrounded by a clear 

 hyaline vesicle and becomes a cytoplasmic structure. During the 

 vegetative stages no change can be observed in this granule, but 

 as the stages of the next successive mitosis proceed it is seen to 

 lose its staining capacity and as a rule disappears before the late 

 anaphase. In some cases it has been seen to persist throughout 

 the division and to be distributed to one of the daughter animals. 

 In this case a single cell would be seen to contain two such 



