M. Koidzumi 
279 
in some other trichonymphids. Some of them are doubtless adherent micro¬ 
organisms, but some are probably peculiar appendages similar to those de¬ 
scribed in other Protozoa by such names as “bristles,” etc. One other charac¬ 
teristic structure of the members of this group is an elastic filament, which 
I shall call the axial filament (“undulating cord” of Leidy and “flagellum” 
of Porter), lying in the protoplasm and stretching from the anterior tip of 
the body to the posterior end or its vicinity. The flagellar cords arise at the 
anterior tip of the axial filament and run spirally backwards, attached to the 
body wall, and become free at the posterior end. The direction of the spiral 
is always left-handed (laeotropic). Porter described the direction of the spiral 
of the cords in the American species as right-handed, but the figures given 
by him are drawn as left-handed. I think it probable that his description is 
a mistake, and his figures are correct. The drawings of Grassi are left- 
handed 1 . 
This group comprises two genera of the American authors, i.e. Pyrsonympha 
and Dinenympha, two of the three oldest genera established for the Protozoa 
of American termites by Leidy in 1877. One species was described by him 
under each of these genera, and figures were given in his later work (1881). 
The same names were applied by Porter (1897) to similar forms, studied by 
himself in the same country. Grassi (1893), in his work with Sandias dealing 
with the Italian termites, described two species which he referred to the above 
two genera. The form referred by him to the genus Pyrsonympha is one 
thickly covered with flagella, differing distinctly from the type of the genus 
described by the American authors. It is thus unquestionable that he made 
an error in the application of the generic name. He has himself corrected 
this mistake in later publications (1911, 1917); and the organism which he 
originally called by Leidy’s name is now the type species of the genus Spiro- 
trichonympha , established by him (Grassi, 1911). The forms described by 
Grassi (1893) under the name of Dinenympha gracilis differ also from the 
forms to which Leidy gave that name, and represent several types with the 
characteristics of both Pyrsonympha and Dinenympha of the American 
authors. Originally Grassi did not draw any distinction between Leidy’s two 
genera; but it appears that he is now of the opinion that the type forms of 
the two genera are merely different stages of growth of a single form; and in 
a review of the genera given in his work which appeared in 1911, the two 
were united into one genus, Dinenympha. Comes (1910 a) seems to be of the 
same opinion as Grassi, for he put forward the view that various forms 
referable to Leidy’s two genera represent different stages of development of 
Dinenympha gracilis. The organism which he described as “ Pyrsonympha ” 
subsequently (1912) is in reality Spirotrichonympha and Holomastigotes. 
However, he has also described an organism closely similar to Leidy’s Pyrso¬ 
nympha, referring it to the new genus Lophophora (1910). Grassi (1911) 
regards this as a stage in development of the same organism, and refers it 
1 Grassi and Sandias (1893), “ Dinenympha gracilis Plate V, figs. 11-14. 
