Geographic Distribution: England.
Prevalence: Robertson (1932) found this species in 1 out of 86 sheep in a London abattoir.
Morphology: The protozoa were described from cultures. The body is slightly ovoid or nearly spherical, 3 to 14 by 3 to 10 u, with 2 anterior flagella, one 12 to 16.5 u and the other 7.5 to 10.5 u long. The undulating membrane is poorly developed but extends the whole length of the body. A free flagellum was described as present, but was absent in 7 out of 9 drawings. A costa is present. The axostyle extends beyond the body. Three blepharoplasts and another granule described as a parabasal body are present.
Cultivation: Robertson (1932) cultivated D. ovis in TanabeTs medium with or without added rice starch.
Remarks: Robertson's paper was apparently overlooked by Grasse, Reichenow and others who discussed the validity of the genus Ditrichomonas. Robertson insisted that there are only 2 anterior flagella except when the protozoa are dividing. No one else appears to have studied the intestinal trichomonads of sheep carefully, altho they are more common in the United States than Robertson found them to be in England. Whether they are the same species remains to be determined.