295 
M. Koidzumi 
Type 3. The body is lanceolate or club-shaped, and its edges may be 
distinct or indistinct. Commonly the organism is longer and more slender 
than those of the above two types, measuring 25-80 /jl in length and 6-10 p, 
in width. The axial filament is very thick. The body is thickly covered with 
filamentous appendages, diffusely distributed over almost the entire surface. 
At the posterior region they are particularly dense, and at the anterior end 
they are somewhat denser than in the middle portion (PL XV, fig. 81). 
Type 4. Resembles the forms of the foregoing type, and is usually indis¬ 
tinguishable in fixed and stained preparations. The mode of arrangement of 
the filamentous appendages, however, is very peculiar in this type. They are 
not distributed diffusely on the surface but are arranged in transverse rows 
varying from 12 to 18 in number. The body is a little smaller than in the 
preceding type. 
Whether any or all of these types should be regarded as distinct species 
or not is. a question hard to answer decidedly at present. To give a correct 
answer the nature of the filamentous appendages must be exactly determined. 
My observations in this respect being still inadequate, my knowledge of these 
structures is limited. Some of the filaments, such as those seen at the posterior 
end of the body of the forms of Type 2, are probably micro-organisms attached 
to the body wall. Some of them, however, such as those at the anterior end 
of the forms of the same type, seem to have certain peculiarities, if taken for 
attached micro-organisms. As for those such as are seen in Type 4, I am of 
the opinion that they should not be regarded as micro-organisms, but are 
rather similar to, or homologous with, the “bristles” described by Janicki 
(1915) in Parajoenia. In my former paper in Japanese I described each of 
these types under a specific name ( D . nuda, D. corniculata, D. porteri, and 
D. comosa respectively); but now I think it better to leave the question of 
their identity in doubt, provisionally calling the group by the name D. porteri. 
PART II. GENERAL DISCUSSION. 
1. COMPARATIVE MORPHOLOGY. 
The forms belonging to the Trichonympha series are of very varied organi¬ 
zation, and the differences among them are so striking in many cases that one 
cannot help doubting whether they belong to one and the same group in the 
system. Both the forms of complicated organization, as well as those of 
rather simpler structure, are provided with some peculiarities. The members 
of the Pyrsonympha series also have many peculiarities in their organization. 
Consequently, the comparative morphological study of all these forms is 
most interesting and important. Notwithstanding, however, a rather rapid 
advance in our knowledge in recent years, this subject has hardly been 
touched upon by any authors: but as I have fortunately been able to study 
many forms and, especially, the process of division in several of them, I shall 
undertake to discuss these questions here. 
