M. Koidzumi 
265 
arrangement of the flagella is also peculiar. There is no special layer, as seen 
in the preceding forms, on the body wall, but it is provided with a thin but 
rigid membrane or periplast. The flagella are not distributed diffusely, but 
are arranged in distinct transverse rows, and become free at the edge of each 
of the transverse folds. A band of deeply stainable granules is distinctly 
discernible at the bottom of each groove formed between two successive 
ridges. It is from this band that the flagella arise, and it can hardly be doubted 
that a row of basal granules exists somewhere in the band, though its precise 
location is not clearly visible. The flagella of this form differ from ordinary 
flagella or cilia in their relation to the body wall, their basal portions being 
adherent to the periplast. They run backwards, fixed on the surface, until 
they reach the summit of the fold, where they become free. Each flagellum 
measures about 30 /r in length, the free portion constituting about two-thirds 
of the entire length (PI. XIII, fig. 53 a). 
In the anterior part of the body, some peculiar filamentous structures, 
varying in size as well as in number, are usually seen in the endoplasm. They 
Text-fig. B. Diagrammatic drawing of various conditions of the ridges on the body wall of 
Terntonympha. Explanation in the text. 
are commonly bent at the anterior end, the main portion of the filament 
usually lying longitudinally. They are composed of a transparent substance 
showing sometimes a fibrous structure, and are covered thickly by minute 
but deeply stainable granules. From two to five may be present, and they 
are invariably found close behind the nucleus (cf. PI. XII, fig. 24). 
Dividing forms are occasionally met with in this species as well as in the 
Formosan variety. The process of division is analogous in essential points to 
that of Trichonympha and Pseudotrichonympha , but is more complicated. In 
individuals beginning to divide, the body is shortened and widened, especially 
at the anterior end, so that the organisms become turnip-shaped. The axial 
column of the head is divided longitudinally. PI. XII, fig. 28 represents an indi¬ 
vidual in an early stage of the process: the axial column is already split into two 
equal halves, and a filamentous strand, identical with that seen in Tricho- 
nympha, is seen lying near its base. The two ends of the strand of this form are 
separated from the column; but there is a thread-like structure connecting each 
end of the strand with the base of each daughter column (PI. XII, fig. 29), like 
that seen in Pseudotrichonympha. At either end the strand is provided with 
