Thus a new light is shed on the origin of the Coccidiaceae, whose "blasts" in the insect host resemble _Trypanosoma_ in their morphology. [Illustration: FIG. 39.—Morphology of _Trypanosoma_. _a-f_, Stages in development of _Trypanosoma noctuae_ from the active zygote ("ookinete"); _b_, first division of nucleus into larger (trophic) and smaller (kineto-) nucleus; _c_, _d_, division of smaller nucleus and its transformations to form "blepharoplast" and myonemes; _f_, adult _Trypanosoma_; _g_, _h_, _i_, _Treponema zeemannii_ of Owl; _g_, Trypanosome form; _h_, _Spirochaeta_ form; _i_, rosette aggregate. (After Schaudinn.)] The human Tick fever of the Western United States and the epizootic Texas fever are known to be due to blood parasites of the genus _Piroplasma_ (_Babesia_), of which the free state is that of a Trypanosome. It appears certain that Texas fever, though due to Tick bites, is not transferred directly from one beast to another by the same Tick; but the offspring of a female Tick that has sucked an infected ox contains Trypanosome germs, and will by their bites infect other animals. {121}It would seem probable that the virulence of the Persian Tick (_Argas persica_) is due to similar causes. The Indian maladies known as "Kala Azar" and "Oriental Sore" are characterised by blood parasites, at first called after their discoverer the "Leishman bodies," which have proved to be the effects of a _Piroplasma_. _Trypanosoma_ is distinguished by the expansion of its flagellum into an undulating membrane, that runs down the edge of the body, and may project behind as a second lash. In this membrane run eight fine muscular filaments, or myonemes, four on either surface, within the undulating membrane; at their lower end they are all connected with a rounded body, the "blepharoplast," which is here in its origin, as well as in its behaviour in reproductive processes, a true modified nucleus, comparable in some respects, as was first noted by Plimmer and Rose Bradford,[133] with the micronucleus of the Infusoria. Part of the segmentation spindle persists in the form of a filament uniting the blepharoplast with the large true functional nucleus (Fig. 39, _a-f_). The blood of patients suffering from relapsing fever contains a fine wriggling parasite, which was described as a Schizomycete, allied to the bacteria, and hitherto termed _Spirochaeta obermeieri_. Schaudinn has shown that this and other similar blood parasites are closely allied to _Trypanosoma_; and since the original genus was founded on organisms of putrefaction which are undoubtedly Schizomycetes, Vuillemin has suggested the name _Treponema_. _T. pallidum_ is found in syphilitic patients, and appears to be responsible for their illness.[134]