D. L. Mackinnon 
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flagellate individuals from one another is the periplast, which in 
Folymastix is well-developed, and characteristically raised up into 
longitudinal “ ribs ” or minute folds. 
These “ribs,” which in the living organism appear to lam almost 
unbroken from one end of the flagellate to the other, are seen on staining 
to be discontinuous, and to fall into groups of shorter', darkly-staining lines 
inclined at various anglesb There appears to be a small cytostome 
between the two groups of flagella, and the cytoplasm contains ingested 
bacteria, etc. 
In certain cases this periplast disintegrates (Figs. 15 and 16), and it 
seems to me not impossible that the Folymastix may, through loss of 
its pellicle, pass into a Monocercomonas form : in such cases, the two 
genera, as represented by the parasites from Tipida at least, could no 
longer be regarded as autonomous. A careful study of the division and 
encystment can alone decide whether this is the case or not. With 
regard to the division I can as yet say very little, but it appears to me 
that the axis of the division-spindle comes to lie parallel to the long 
axis of the body, in which case authors’ statements that the division is 
transverse would not be far out. 
The genus Folymastix was formed by Biitschli to include Grassi’s 
Trichomonas melolonthae. So far, no reliable species have been added 
to the genus^ the solitary occupant of which, not examined since 1884, 
“ bedarf dringend der Nachuntersuchung ” (Doflein, 1911). Hamburger 
(1911) has recently published a preliminary note, including observations 
on Folymastix melolonthae. She finds the same parasite also in the 
larvae of Getonia. In various points, such as the presence of an axostyle 
and the details of nuclear structure, my flagellate differs from the 
^ Grassi interpreted these structures as “ trichocysts.” On first seeing them, I was 
inclined to regard them as bacilli adherent to the body of the flagellate (cf. Kiiustler, 1882), 
or else ingested and in some way come to form a sort of thin layer just below the 
periplast. Various points plead in favour of this view, notably the occurrence of such 
individuals as that figured in Figs. 15 and 16. However, I have recently abandoned the 
idea, and consider that Frl. Hamburger’s interpretation is probably the right one—“mir 
scheinen es verdickte Streifen der Pellicula zu sein.” 
M. Alexeiefl has drawn my attention to a similar appearance presented by the periplast 
of Lophomonas striata Biitschli, from the cockroach, recently described in detail by 
Janieki (1910). 
It is interesting that an unstriated form, Lophomonas blattaruni, lives alongside this. 
I believe that a comparison of Folymastix with these Trichonymphids may not be 
unprofitable. 
2 The flagellate with six flagella and without striated periplast, placed provisionally by 
Alexeiefl (1911) in this genus as P. bufonis, seems to me a very doubtful species. 
