N. 11. SWELLENGRBBP]L 
127 
V. Summary. 
1. lu accordance with the views held by Chattou and Alilaii’e 
(1908) and by Roubaud (1909), I have seen that a true trypanosome- 
stage occurs in the life-history of Grithiclia calliphorae. These try¬ 
panosomes have an undulating membrane and cannot be considered as 
herpetomonads with their blepharoplasts situated behind the nucleus 
and a completely internal flagellum (Woodcock), nor are they herpeto¬ 
monads with the flagellum bent back along the body of the cell 
(Mackinnon). This existence of a trypanosome stage in the life-history 
of GritJiidia is quite comprehensible if we consider that in many cases 
true Trypanosomata are changed into Grithidiae when they pass from 
the blood into the gut of an invertebrate host {T. gamhiense, T. leivisi, 
ScJdzotrypanum cruzi, etc.). 
2. There is no sharp difference between the genera Grithidia and 
Herpetomonas. In Grithidia calliphorae forms may be observed without 
any trace of an undulating membrane (Diagram I, Fig. 1); in 
Herpetomonas calliphorae such an organellum may be sometimes 
present (Diagram IX, Fig. 4), 
Still I think that it is not permissible to throw these two genera 
together, as, generally speaking, an undulating membrane is present in 
Grithidia and absent in Herpetomonas. 
3. Herpetomonas is often biflagellate, even when no signs of 
cellular division are present and the flagellates multiply less actively 
than in monoflagellate stocks. Still I agree with Patton that this 
biflagellate condition is too inconstant to permit of its being recognized 
as of generic significance. 
4. The structure of the blepharoplast of Herpetomonas is distinctly 
like that of a nucleus, with peripheral chromatin and one or more 
central granules. It is true that the behaviour of these granules during 
the division is not so regular as that of the karyosomes of real nuclei, 
nevertheless, I think that the aspect of the blepharoplast of H. calli¬ 
phorae is a strong argument in favour of Schaudinn’s, and also Minchin’s, 
view that this organellum must be regarded as a specialized nucleus 
(kinetouucleus). 
5. The flagellum of Grithidia calliphorae is constructed in the 
same way as that of Trypanosoma leivisi: a basal granule is present 
and the new flagellum is formed by the production of a new flagellar 
root by fission of the basal part of the old flagellum. In Herpetomonas 
