3, E), which is to be derived from a Herpetomonadine type, the single, anterior flagellum of the ancestral parasite has been drawn backwards along one side of the body and now originates in the posterior half.
At this period they have, in fact, what may be termed a " pseudo-Herpetomonadine " aspect.
- Haemoflagellates derived from a uniflagellate, Herpetomonadine form, in which the point of insertion of the single (anterior) flagellum into the body has travelled backwards from the anterior end for a greater or less distance, the flagellum itself having become, concurrently, attached to the body for a portion of its length by means of an undulating membrane.
It is, for instance, quite likely that certain Herpetomonadine parasites described by Leger (2 9, 34) from various blood-sucking insects are really only stages in the life of a Haemoflagellate.
Nevertheless, the general appearance and structure of these motile forms so greatly resemble that of a Herpetomonad, or of the " pseudo-Herpetomonadine " forms of a Trypanosome which are obtained in cultures, that it cannot be doubted that the " Leishman-Donovan-Wright " bodies are closely connected with the Haemoflagellates.