THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 24] 
mately the same stage. It is therefore impossible to describe 
the whole of the process. 
Two of these stages are figured in PI. 3 (figs. 40, 41). 
According to my interpretation it appears probable that 
division is longitudinal and effected in the same way as in the 
trichomonads—allowing, of course, for the more complex struc- 
ture. Before division the axostyles would therefore be 
absorbed, and with them the caudal flagella. A stage with 
only six flagella—all at the anterior end—would thus result. 
We do, indeed, find such organisms on rare occasions (see 
fig. 46), but I am inclined to think that they belong to a 
different species (see p. 245). However, they possibly belong 
here. ‘The nucleus would subsequently divide, new flagella 
would make their appearance, three at either end, and we 
should expect to see two axostyles lying between the nuclei 
as they separate. ‘his is the condition which I imagine is 
seen in figs. 40 and 41. Later, when the axostyles had elon- 
gated and the animal had been constricted into two, the 
caudal flagella would make their appearance, either by a new 
growth or by the drawing out of the axostyles at the point of 
severance. Both the organisms figured were very distinct, 
and in fig. 41 the suggestion of the outgrowth of new flagella, 
as in Trichomastix, is very strong. The bipartite nuclei 
are also very striking, and it seems difficult to regard these 
forms otherwise than as division stages. But as I have 
already indicated, the evidence of division is by no means 
conclusive. I give these few observations because | have 
completely failed to discover anything more, and because the 
descriptions of division in similar forms seem to me to be 
incorrect. 
Encystment.—When the organisms are artificially 
removed from their host or liberated in the feces they nearly 
always die. For a long time I was unable to discover the 
cysts or the method of dissemination in nature. On a few 
occasions, however, I have found the permanent cysts of 
Octomitus, though they have never occurred in anything 
but very small numbers. The cysts are small and usually 
