STRUCTURE AND DIVISION OF TRICHOMONAS 141 



any metaphase figures for T. muris, and even in their extensive 

 figures for T. augusta they have nothing corresponding with my 

 figure 22. They therefore inissed the evidence showing that the 

 process of separation at the metaphase and anaphase corresponds 

 to the details as seen in the corresponding stages in metazoan 

 mitoses, except for the precocious separation toward the two 

 poles before the equatorial plate is completely formed. Their 

 figures 20 and 21 for T. augusta in which the metaphase chromo- 

 somes are seen as single elements elongated in the direction of the 

 spindle axis possibly show conditions in which the constriction 

 between the separating chromosomes has been eliminated by 

 contraction of the chromatin in the process of fixation. 



C. Anaphase 



Figures 26 and 27 illustrate anaphases. I have not seen so 

 many anaphases as I have metaphases, and presume that this 

 phase is of shorter duration. During this stage the chromosomes 

 appear to become elongated (fig. 26) and constricted (fig. 27). 

 Figure 27 shows the smallest chromosome as having divided 

 precociously and the daughter elements are much nearer the 

 poles than those of the other chromosomes. 



D. Telophase 



After the chromosomes have been completely separated and 

 the two daughter groups have arrived at positions some distance 

 apart, the nucleus which has been elongating during the anaphase 

 (fig. 27) becomes constricted in the middle (figs. 28 and 29), 

 thus forming the two daughter nuclei. The nuclear membrane 

 persists throughout this process. In the early telophases the 

 chromosomes begin to change their appearance, becoming less 

 dense and more granular. The constriction which first appeared 

 in the anaphase becomes more pronounced and each of the former 

 chromosomes appears to be made up of two rounded or slightly 

 elongated parts in contact at the ends (fig. 31) . These eventually 

 give rise to the scattered granules seen in the resting nucleus 

 and the new caryosome becomes established surrounded by its 



