STRUCTURE AND DIVISION OF TRICHOMONAS 137 



I have not found stages with the so-called ^nuclear cloud' 

 as described by Kofoid and Swezy ('15) as shown in their figure 

 49, nor have I seen the spirene stage shown in their figure 50. 

 My figure 9 shows a condition somewhat similar to their figures 

 46 and 47, but I think such nuclei are abnormal, particularly 

 since they are so much larger than usual and often accompany 

 other evidences of degeneration, 



2. Chromatic basal rod. Coincident with the intranuclear 

 changes of the early prophase, the new chromatic basal rod 

 makes its appearance. Usually it appears some time before 

 the blepharoplast has divided and is very difficult to recognize 

 in its earliest stages. Figure 11 shows the earliest stage in 

 which I have been able to find this structure, and here it will 

 be seen to consist of a row of very fine granules closely connected 

 together and joined to the blepharoplast. Figure 10 shows a 

 stage which seems to be a little later, judging by the nuclear 

 changes, and here also the new chromatic basal rod is a row of 

 granules, but much longer than the one in figure 11. I was 

 unable to trace it past the nucleus and up to the blepharoplast. 



The new rod is always in a characteristic position, dorsal to, 

 and to the right of, the nucleus (figs. 10 to 17). Although rela- 

 tively slender at first, it gradually increases in size until by the 

 time the blepharoplast divides it is easily recognizable. After 

 the division of the blepharoplast the new rod does not always 

 maintain its position near the surface of the body. In figure 19, 

 for example, the new blepharoplast is at the upper surface, while 

 the new rod extends from it around the nucleus, deep into the 

 protoplasm to the lower surface. 



3. The new undulating membrane and chromatic 7nargin. As the 

 new chromatic basal rod grows, irregular thickenings appear 

 along its length, as indicated in figures 12 and 15. A little 

 later one can see the new chromatic margin of the new undulating 

 membrane closely applied to the new rod (figs. 19 to 21). In 

 its first recognizable condition this chromatic margin is of much 

 smaller caliber than the old one, its undulations are low and 

 in length it cannot be traced beyond the distal end of the new 

 rod (figs. 20 to 26). In figure 19 it was possible to trace the new 



