TRICHOMONAD FLAGELLATES. 357 



covina where intranuclear phenomena are, as far as known, quite 

 similar) of an intranuclear spindle on which the chromosomes are 

 divided. 



Janicki holds that the chromatic bodies seen in mitosis are not 

 chromosomes but plurivalent chromatic strands, organized of numer- 

 ous smaller granules or chromosomes. He figures four of these larger 

 bodies in the anaphase. In form and arrangement they resemble 

 the bodies in Trichomonas which we have interpreted as chromosomes. 



In view of the complexity and variety of structure of the extra- 

 nuclear motor apparatus in the Trichonymphida sensu strictu and of 

 the divergence of results between Janicki and ourselves as to the fate 

 of the axostyle, of the origin of the division centers at mitosis, and as 

 to the nature and status of the chromosomes in the group of complex 

 flagellates, it is very desirable that the process of mitosis be more fully 

 investigated than has been possible with the limited material thus far 

 available. The homologies of the axostyle and parabasal in Lopho- 

 nionas and in the multinucleate trichonymphids with the simple 

 structures in Trichomonas should be adequately established by a 

 series of comparative studies in the former group and the history of 

 organelles traced through the critical late and postmitotic periods. 



Conclusions. 



1. The upper part of the large intestine of most vertebrates is in- 

 fected by trichomonad flagellates whose phases of mitosis and mul- 

 tiple fission occur at intervals and are met with in a few of the many 

 hosts examined. These processes are carried out during periods of 

 great amoeboid activity of these parasites in the mucus of the intes- 

 tinal epithelium. 



2. Mitosis is promitotic with nuclear membrane intact throughout 

 the period of division, with nuclear separation by constriction simu- 

 lating amitosis. It is, however, essentially mitotic with extranuclear 

 division centers, intranuclear spindle fibres, chromosome organization 

 out of a chromatin network and skein. 



3. The chromosomes are definite in number, four in Tetratricho- 

 monas prowazcki, and five in Trichomonas awjusta, T. muris, and 

 Eutrichomastix serpentis. They are differentiated in form, there 

 being one small one, and some fairly constant size dift'erences among 

 the larger ones. They are differentiated in behavior, the small one 



