STRUCTURE AND DIVISION OF TRICHOMONAS 125 



C. Organization of the cell 



The organelles of this species of Trichomonas are those typical 

 of the genus and are indicated in text figure A. They include 

 besides the nucleus {d) and cytostome Q) the series of structures 

 attached to the blepharoplast (a), consisting of the three anterior 

 free flagella (rw), the long posterior flagellum running as the 

 chromatic margin {i) of the undulating membrane (6) and con- 

 tinuing posteriorly as a free flagellum {n), the chromatic basal 

 rod {h) at the base of the undulating membrane, the axostyle 

 (j), the parabasal body (/)'and the inner (e) and outer {g) rows 

 of chromatic granules. 



The protoplasm is enclosed in a cell membrane or pellicle, 

 which, as previously noted, is flexible enough to permit vari- 

 ations in form. These form variations may be classed as 'eugle- 

 noid' in type. Pseudopodia formation has been described by 

 several authors, for example, by Kuczynski ('14) and by Kofoid 

 and Swezy ('15), but I have seen such apparent pseudopodia 

 only under conditions which appeared to be either degenerative 

 or precystic, and therefore I do not regard this phenomenon as 

 normal for the active individual. The protoplasmic projection 

 shown in figure 16 is probably the result of mechanical injury 

 in making the smear, and is not a pseudopodium. 



The protoplasm itself is rather fluid in nature, as is indicated 

 by the rapidity with which form changes occur. It appears to 

 be somewhat vacuolated, although not to the extent seen in 

 some other species, such as T. augusta, as figured by Kofoid 

 and Swezy (15), or T. mirabilis, as figured by Kuczynski ('18). 

 The appearance or non-appearance of vacuoles seems to vary 

 somewhat from host to host and from cell to cell. Variations 

 from one fixative to another are discussed further on. 



The nucleus (text fig. A, d) lies in the anterior third of the 

 body dorsal to and usually a little to the left of the axostyle 

 which occupies the position of the principal axis. It is usually 

 oval or broadly elliptical in shape, being approximately 4 to 5)u 

 long and 2.5 to 3/x wide. At the periphery is a delicate nuclear 

 membrane or caiyotheca, which is sometimes difficult to see. 



