R. Kudo 233 
There is a little difficulty in distinguishing young stages from the leuco- 
cytes in the fresh state. The larger trophozoites can easily be distinguished 
from any other objects found in the preparations even in unstained conditions. 
An unmistakable character of a living trophozoite is the presence of four 
polar capsules under formation, even when no nucleus can be detected in 
the body. The cytoplasm of larger trophozoites is clearly differentiated into 
two parts, the ectoplasm and the endoplasm. Wfien a drop of emulsion of 
an infected kidney in physiological solution is made into a hanging drop 
preparation, large trophozoites will be seen to produce active pseudopodia 
from localized parts or from the entire surface of the body (Fig. 89). The 
pseudopodia are those that have commonly been seen iu several species of the 
family Ceratomyxidae. They are of a long conical form and end in points. 
When the trophozoites are kept in the preparation for from 3 to 8 hours, the 
pseudopodia are withdrawn, and lobose ones may be seen sluggishly formed 
in their place. Frequently even in freshly-made emulsion, rounded tropho¬ 
zoites without any pseudopodia are encountered (Fig. 87). The ectoplasm is 
especially visible at the place where the pseudopodia are formed, they are 
entirely composed of the ectoplasm. In rounded forms, the differentiation is 
poor (Fig. 87) and the ectoplasm forms a rather tough homogeneous hyaline 
layer around the body. The endoplasm is finely reticulated, and in places 
greatly vacuolated. The trophozoite contains spherical bodies of variable size 
(Figs. 87-89), which are of fatty nature. 
MORPHOLOGY OF THE SPORE. 
The mature spores are, as a rule, rounded elliptic with the longest axis 
standing at right angles to the sutural plane 1 (Figs. 87-98). The form varies, 
however, considerably. Frequently the breadth is reduced to that of the 
sutural diameter so that the spore approaches a sphere in the front view. In 
all cases, the anterior tip is more or less drawn out due to the thickening of 
the spore membrane at that point. -The posterior margin is always rounded 
except the sutural ridge which stands out prominently at its middle portion. 
In the anterior end view, the spore is elliptic (Fig. 87), while in profile, it is 
almost circular with a slightly pointed anterior end (Fig. 99). The spore 
membrane is moderately thick, and is composed of two valves of usually 
equal size and form. The anterior tip of each valve is thickened and forms a 
small rounded highly refractive body (Figs. 87, 92, 96-98). The sutural ridge 
is straight and prominent. The spore membrane is marked with numerous 
striae, the pattern of which can be easily studied on an empty spore. Al¬ 
though the striation is apparently irregular in many spores, the following 
pattern is recognized in most cases: A few striae, three to seven, run parallel 
to the sutural line, while all the others form somewhat similar angles with the 
sutural line (Figs. 91, 93, 95). Frequently the latter striae on each valve centre 
1 The definitions of the terms used here, are given in one of my papers (Kudo, 1920a). 
