STRUCTURE AND DIVISION OF TRICHOMONAS 145 



parts of this complicated flagellate that divide equationally. 

 They are, 1) the nucleus, including the chromosomes, and, 2) 

 the cell body. The blepharoplast, chromatic basal rod, posterior 

 flagellum, and possibly also the parabasal body and one or two 

 of the anterior flagella of the parent appear to be retained by 

 one of the new daughter individuals, while the other daughter 

 is supplied by new outgrowths, including a new small blepharo- 

 plast budded off from the parent one. The old axostyle, and 

 possibly also the old cytostome, disappear and a new one is 

 formed for each new cell. New chromatic granules appear to 

 have a different origin, as previously described. This behavior 

 is paralleled by that of the Infusoria, exemplified by Paramecium, 

 which remains active during the process of division. Some of 

 the cilia and one of the contractile vacuoles are taken by each 

 daughter cell, and new ones are formed to make the complete 

 set of organelles. Part of this development in Paramecium 

 takes place after the separation of the daughter cells, whereas 

 in Trichomonas development of the new organelles appears to 

 be completed before the daughters separate. Since in both cases 

 the daughter cells come to resemble each other completely, their 

 hereditary potentialities must be equally descended from the 

 parent. An equational division of the nuclear material would 

 therefore be sufficient to insure equality between the daughter 

 cells, granting that the nuclear material constitutes the physical 

 basis of heredity. 



SU^IMARY OF THE :^IORE BIPORTAXT RESULTS 



1. Trichomonas muris (Hartmann) from the coecum of the 

 mouse measures 10 to 16^ long by 5 to lO/x wide, but varies in 

 size slightly from host to host and to a larger extent as a result 

 of the use of different fixatives. 



2. Different fixatives also give rise to different staining reac- 

 tions of the protoplasmic vacuoles, nuclei, and other organelles. 



3. The anterior free flagella are short, not more than half 

 the length of the body, and stain faintly with iron-alum haema- 

 toxylin stain. The posterior flagellum stains intensely as the 

 chromatic margin of the undulating membrane, but its posterior 



