THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 219 
figured have been wrongly interpreted. His figures, 13, 15, 
and 21 (PI. 11) are really drawn from dividing animals, | 
believe. They correspond closely with what I have myself 
seen. But the remaining figures of “stages in division ”’ are, 
I think, nothing more than degenerate or fused monads. I 
have seen many similar appearances and feel convinced that 
they have nothing at all to do with division. It is remarkable 
also that no figure is given in which asplitting of the axostyle 
is shown. On the contrary, figs. 15 and 21 show a single 
rod extending from nucleus to nucleus—an appearance 
scarcely explicable on the assumption that the rod is formed 
from the split halves of the former axial organ. 
In the second place it is to be noted that the cysts which 
I have found are quite different from those described in allied 
organisms. For the most part the accounts given (Kunstler, 
Perroncito, etc.) are too indefinite to allow of comparison 
being made, but in one case at least (Prowazek [73]) there 
exists a full account of encystment, and it differs widely from 
what I have seen. But it is fruitless to discuss the matter 
further at present. 
I have never found any signs of the formation of those 
curious rounded-off, half-encysted forms, which, according 
to Wenyon, occur in Trichomonas from the mouse, and 
which probably bring about infection. I do not believe 
any such condition occurs in the trichomonads from frogs 
and toads. 
Finally, it is necessary to say something about the problem 
of hosts and species. All I wish to say is that the tricho- 
monads I have observed appear to me to be sufficiently well 
marked to be kept specifically distinct for the present. As 1s 
well known, a Trichomonas intestinalis has been 
described from many different hosts. Whether there is really 
one species, or more than one, our present state of knowledge 
does not permit us to decide. Similarly, in spite of their 
great resemblance, I believe ''richomonas and Tricho- 
mastix are sufficiently well distinguished from one another to 
be placed conveniently in different genera, without entering 
