350 KOFOID AND SWEZY. 



verse separation as the chromosomes are at that time located in the 

 spindle, thus resembhng this phase of the process in Trichomonas. 



The anaphase (PI. 7, Figs. 89, 90) is quickly accomplished, the 

 migration of the chromosomes and their ultimate attachment to the 

 polar blepharoplast extending into the telophase as in Trichomonas. 

 During the late anaphase the nuclear membrane (PI. 7, Fig. 90) con- 

 stricts at the equator and the nucleus takes on a dumbbell shape and 

 the chromosomes increase in size. 



In the telophase (PI. 7, Figs. 91-94) the nuclei are reconstituted. 

 The enlarged chromosomes cluster about the blepharoplast and 

 become attached to them by a dark chromatic thi'ead (Fig. 91). 

 Later they become massed together (Fig. 93) into the central karyo- 

 some. In the meantime the new cytostome has been formed (Fig. 91), 

 and two axostyles are found in place of one (Figs. 91, 92). We have 

 but one slide showing many phases of mitosis and it is unfortunately 

 so decolorized that the originally small and unstained axostyle can- 

 not be traced during mitosis. Two new axostyles appear in this 

 organism, however, at the stage exactly corresponding to that of their 

 formation by splitting of the parent axostyle in Trichomonas augusta. 

 They are also formed prior to the disappearance of the paradesmose 

 (PI. 7, Fig. 93). The incomplete findings here are in accord with the 

 interpretation of the origin of the new axostyles by splitting of the 

 old and not anew from the paradesmose as maintained by Prowazek 

 (1904). The deceptive nature of Prowazek's evidence may best be 

 judged by a comparison of his figures (1904, PI. 1, Fig. 12) with that 

 of a corresponding stage in our material (PI. 8, Fig. 96) in which the 

 long-spun-out deeply stained paradesmose lies immediately over and 

 subparallel to the new daughter axostyles. It is evident that Pro- 

 wazek wholly overlooked these new organelles and mistook the con- 

 tinuous paradesmose for their source. 



Plasmotomy finally separates the two daughter trophozoites and is 

 accomplished after the two nuclei migrate to the poles 180° apart and 

 thus elongate the cytoplasm. This occurs after the paradesmose 

 disappears (PI. 8, Figs. 95, 96, 104). During this stage the tropho- 

 zoites are exceedingly active as in Trichomonas and assume a great 

 variety of relations in rapid succession. For example in one instance 

 in a preparation (PI. 8, Fig. 97) the two trophozoites are each 

 surrounded by a spheroidal mass of cytoplasm and still connected 

 by a cytoplasmic bridge containing the paradesmose. The two are 

 quite unequal in diameter. This might be interpreted as indicative 

 of unequal division or in the absence of the paradesmose, as the copula- 



