SYMBIOSIS BETWEEN TERMITE AND FLAGELLATES. 323 



days, but was never able to fill the intestine with protozoa, that 

 is to say, Trichomonas was never able to entirely take the place of 

 Trichonympha and Leidyopsis in volume. Most of the termites 

 of this group were able to live 70-80 days and some of them 

 longer, although very few, if any, were able to live indefinitely. 

 Trichomonas, then, is of some value to its host as a symbiont. 

 It can keep its host alive 40-50 days longer than the host would 

 be able to live without it. If Streblomastix. which is certainlv 



f 



not of any value to its host and may have to be supported by 

 Trichomonas in this group, were not present, Trichomonas might 

 Ix of more value to its host. 



\\'l it-ii group (3), which contained Streblomastix, was fed wood, 

 It Mill n-Milted within three to four weeks, the same time it 

 occurs \vlit-ii .ill protozoa are removed. Streblomastix did not 

 multiply at all; on the contrary, it gradually diminished in 

 number. This protozoiin. then, is not a symbiont. It may 

 t-itlu-r arrive its nourishment from its host or from the other 

 I'loio/o.i dirrrtly, probably the latter. 



Wlirn group (4), which contained Trichonympha, Leidyopsis 

 .iii-l Streblomastix, was fed wood, all individuals were able to live 

 indrlmitrly. The removal of Trichomonas did not seem to affect 

 tin- ^ymbioMs at all. Trichonympha perhaps took the place of 

 J'n'i homonas very quickly. 



\\ In 11 K'oiip (5). which contained Leidyopsis and Streblomastix, 

 \\.i- ifM \\ood, Leidyopsis multiplied and increased in numbers 

 juM .1- it did in group (i), perhaps taking the place of Tricho- 

 ninnns though this could not actually be seen just as it did 

 th.it of Trii honymplui. These termites were able to live in- 

 definitely. Leidyopsis, even though in nature its ratio to Tricho- 

 nytn()hti i> .ipproxim.iU'ly I : looo, can take the place of Tricho- 

 nympha under experimental conditions both, in number and in 

 ability to keep it- lio>t alive indefinitely. In nature, however, 

 Trichonympha niu-t U- the chief symbiont, for it is so much more 

 numerous than its closest neighbor, Leidyopsis. 



\\ hen group (6), which contained no protozoa, was fed wood, 

 dr.ith resulted within three to four weeks. 



The results of tlu-r experiments, as regards the >yml>iotic 

 relationship between termites and their intestinal protozoa, are 

 in accord with those obtained by the incubation method (Cleve- 



