44 University of California PuMications in Zoology [Vol. 20 



The flagella continue moving as long as they are visible at the begin- 

 ning of this process but soon disappear. 



Dilute egg albumen has been found to be the most satisfactory 

 culture medium but even with this these flagellates have been kept 

 alive only a few hours, with the rounding-up process soon visible in 

 a majority of the forms. 



As has been earlier noted for trichonomad flagellates (Kofoid and 

 Swezy, 1915), binary fission in Triehonyvipha campanula is cyclic in 

 its occurrence, being found abundantly in occasional individual hosts. 



In order to secure all stages of the division cycle, preparations were 

 made every day continuously for thirty days, the number of individual 

 hosts used each time varying from three to ten or more. For several 

 days also these preparations were made at two-hour intervals during 

 the day. In this way we have been able to secure a fairly complete 

 series of figures of all stages of the mitotic process. A few isolated 

 division forms may be present in almost any host, but in general it has 

 been found that where more than these occur in a single host, that 

 from one-third to one-half or even more of the individuals of a single 

 parasitic species observed, will present some signs of" division and 

 usuallj' of a single stage of mitosis. This is especially true of the 

 early prophase stages which, on the whole, have been most abundant 

 in our material. A few slides have been found, however, on which 

 almost all stages of the division process may be found. This seems 

 to be the exception and not the rule. 



MORPHOLOGY 



Every observer of the parasites of the digestive tract of the 

 termites is amazed, on his first glance at its seething contents, at the 

 locomotor activities displayed by its constituent organisms. Foremost 

 among these in constancy, agility, and variety of its movements is 

 Trichonympha. It is signficant that Leidy (1877) used the specific 

 name agilis for the first trichonymph discovered. This capacity for 

 motor activities is based on structural features of corresponding com- 

 plexity. Hence it is that any discussion of the morphology of this 

 animal is mainly occupied with the neuromotor system. The only 

 other differentiated structure foimd in the body is the nucleus. There 

 is no apparent mouth, no excretory system, no food-taking organs. 

 The food vacuoles are temporary in a seemingly undifferentiated 

 endoplasm. The structural specialization of this parasite thus affects 

 mainly one organ system only, the neuromotor system. 



