INTESTINAL TRYPANOPLASMAS OF FISHES. 
191 
plasma be accepted, there now remains for discussion the 
question as to which, if any, of the so-called intestinal Trypan o- 
plasmas should be included in the genus Trypanoplasma. 
If the figures of the dividing Trypanoplasma cyprini 
shown in PI. 10 are compared with the figures of the division of 
Trypanoplasma congri shown in Text-fig. 1, bearing in 
mind that the division in the case of Trypanoplasma 
cyprini is a specialised one resulting in the production of a 
slender form, it will be obvious that there are many points of 
similarity. I think that these are probably sufficient to retain 
provisionally the Conger parasite in the genus Trypanoplasma. 
The parasite in Cyclopterus, Heteromita dahlii, appears to me 
to be separated from the true Trypanoplasma by many 
important points of difference. Firstly, the absence of an 
undulating membrane ; secondly, the presence of a mouth and 
ingestion of food; and thirdly, its method of division. I 
believe that a more detailed examination of this parasite will 
lead to further points of difference being discovered, particu- 
larly in connection with the process of encystation, but these 
I must leave for a later paper. 
As regards the parasites in the stomach of Box, if my view 
as to the presence of three free flagella in this form be accepted, 
it is obvious that we are dealing here with a form which is 
much more closely allied to Trichomonas than to Trypano- 
plasma. In this case it will be obvious that the kinetonucleus 
in Trypanoplasmoides is probably not homologous with the 
similar structures in the other forms. Apart from the struc- 
ture of the flagella, there are many other points of difference 
between Trypanoplasmoides and the true Trypanoplasma, 
viz. the presence of a distinct cytostome in Trypanoplasmoides, 
the method of movement, and the method of division. 
I should now like to refer shortly to a structure to which 
it seems to me far too much importance has been attached in 
recent years — the kinetonucleus. If Jollos^s description of 
the division of this structure were to be accepted this 
importance would be justified,' but I think that from the 
descriptions of the division of the flagellates given above it 
