_T. equiperdum_ is about 25 µ to 28 µ in length on an average, but varies from 16 µ to 35 µ. Its cytoplasm is relatively clear, and does not show chromatic granules (fig. 43). It is stated to be monomorphic. It has been shown recently by Blacklock and Yorke (1913)[105] that there is another trypanosome giving rise to dourine in horses. This trypanosome is dimorphic (resembling _T. pecaudi_ and _T. ugandæ_), and is named _T. equi_. Previously _T. equiperdum_ and _T. equi_ had been confused. [105] _Proc. Roy. Soc._, B, lxxxvii, p. 89. Uhlenhuth, Hübner and Worthe have demonstrated the presence of endotoxins in _T. equiperdum_. These endotoxins may be set free by trypanolysis. *Trypanosoma theileri*, Bruce, 1902. This parasite, 60 µ to 70 µ long, and 4 µ to 5 µ broad, is distinguished for its large size, though it is not so large as _T. ingens_ from Uganda oxen, whose length may be 72 µ to 122 µ, and breadth 7 µ to 10 µ. The posterior end of _T. theileri_ is drawn out. Small forms of the flagellate are known, 25 µ to 53 µ in length. Probably other forms of the parasite have the nucleus posterior, and these flagellates were formerly separated as _T. transvaaliense_ (Laveran, 1902). Myoneme fibrils may be seen on its body. The pathogenicity of this organism is doubtful, it was formerly thought to be the causal agent of “gall-sickness” in cattle in South Africa. _T. theileri_ also occurs in Togoland, German East Africa, and Transcaucasia. Allied or identical parasites occur in cattle in India. [Illustration: FIG. 44.--_Trypanosoma theileri._ × 2,000. (After Laveran and Mesnil.)] _Trypanosoma theileri_, specific to cattle, is perhaps transmitted by the fly _Hippobosca rufipes_ in South Africa. *Trypanosoma hippicum*, Darling, 1910. _Trypanosoma hippicum_ causes the disease of mules known as “murrina.”[106] It was found in mules imported to Panama from the United States. It can live in other equines. The parasite varies from 18 µ to 28 µ in length, and is from 1·5 µ to 3 µ broad. Its undulating membrane is little folded. The trypanosome has a noticeable blepharoplast. It can penetrate mucous membranes, and it is thought that the trypanosome may be transmitted during coitus. It may also be spread mechanically by species of _Musca_, _Sarcophaga_ and _Compsomyia_, sucking the wounds of infected animals and carrying over the trypanosomes to wounds on healthy ones. [106] _Bull. Soc. Path. Exot._, iii, p. 381. *Endotrypanum schaudinni*, Mesnil and Brimont, 1908.