D. L. Mackinnon 
249 
protoplasm of the whole body perform the curious undulations described 
by authors in various species of Trichomonas and Trichomastix. 
When swimming freely, the flagellate moves with the jerky, hopping 
action characteristic of trichomonads in general. The three anterior 
flagella lash backwards and forwards in unison: the swing of the 
“ Schleppgeissel ” is not usually simultaneous with that of the rest, but 
falls a little behind. This flagellum may also describe a sort of spiral, 
a movement that probably accounts for the frequent rotation of the 
whole organism. 
I was never able to follow the whole process of division on one 
individual, but I observed a sufficient number in different stages 
to be certain that the process is similar to that described for other 
species. The axostyle is withdrawn, and the animal becomes roughly 
circular in form : then it can be seen that the refractive spot corre¬ 
sponding to the basal granule has become doubled, and that these 
two then move away from one another towards opposite poles of 
the now ovoid body. Certain flagella go with each basal granule, but 
in the living state it is impossible to be quite certain as to their number 
and arrangement. A clear refractive line can sometimes be seen 
extending from one granule to the other. The cell now becomes 
constricted in the middle, and with some rapidity the two halves 
separate from one another, the connecting portion thinning out more 
and more until it snaps, and the daughter flagellates separate. The 
first stages of division are relatively slow, but the final separation is 
rapid, which probably accounts for the rarity of the final stages in 
stained preparations. During division the animal’s movements are 
irregular and jerky, and it does not make much forward progress. 
With regard to encystment I can say very little. Occasionally in¬ 
dividuals were seen to attach themselves to clumps of bacterial matter, 
withdraw their axostyle and apparently round off, but, though watched 
for hours, they never showed any signs of further development. I never 
saw anything of the nature of conjugation between free-swimming 
individuals, though, after some time under the coverslip, the flagellates 
seem to get sticky and tend to adhere to one another when they touch. 
(2) Stained Material. 
In the stained flagellate the chief difference between this and other 
species lies in the great length of the axostyle and in the position of the 
nucleus, which, though sometimes just below the basal granules, is more 
