M. Koidzumi 
291 
as an indication of the existence of a connexion between the nucleus and some 
other part of the body—perhaps the axial filament, as in the other forms. 
As mentioned already, the American authors did not describe any connexion 
between the nucleus and the axial filament in the Pyrsonympha studied by 
them; but the shape and the position of the nucleus, as illustrated by them, 
show resemblances to the conditions in some of the species of Dinenympha 
studied by myself, and I am of the opinion that a special structure connecting 
the nucleus and the axial filament exists also in the American species of 
Pyrsonympha. 
Like Pyrsonympha , the species of Dinenympha live both hanging from the 
intestinal wall and swimming freely in the lumen of the gut. Freely swimming 
individuals move very vigorously. They display both rotation and flexion, 
and in slender forms the anterior end is actively swung in all directions. 
Dividing forms are met with very rarely. The process of division seems, 
as far as I could conjecture from several stages that came under my notice, 
to be of the same type as that observed in Pyrsonympha (PI. XV, figs. 83 
and 84). 
Several forms are to be distinguished in this subgenus, and in my earlier 
account (1917) I described them as nine species and one variety. At present, 
however, I feel that it is better to regard the independence of some of the forms 
as questionable, and here I propose to classify them under six species and one 
doubtful species. 
The forms harboured by Leucotermes speratus of Japan proper and those 
in Leucotermes flaviceps of Formosa are not identical, three species and the 
doubtful one being common to both species of termite. 
(1) Dinenympha exilis sp. nov. (Plate XV, figs. 67 and 68, 
and Text-fig. E, a). 
The body is long and slender, the greater portion being almost uniform 
in thickness though it tapers gradually at the extremities. -It measures 
50-100 /x in length and 4-8 p in width at the middle. The number of complete 
spiral turns of the whole body is commonly two or two and a half: so that in 
side view four or five undulations are commonly visible. When the organism 
does not move very actively, its body is oval or elliptical in cross section; 
but when it moves actively the body becomes somewhat more flattened. The 
surface of the body is almost smooth, the ridges on which the flagellar cords 
are situated being very indistinct. The axial filament is thick, but becomes 
slightly thinner towards the posterior end. The endoplasm is clear and food 
debris is rarely contained in it. The nucleus is of an elongated oval shape, 
and is situated at the anterior extremity of the body, as a rule; but occa¬ 
sionally it is found near the middle or in the hinder regions. 
This species is found in both Leucotermes speratus and L. flaviceps. No 
forms taken to be of this type are found in the descriptions of the American 
authors. 
