In this holotrichasin gymnostomorid family, the cytostome is usually at the anterior end, there are ordinarily a posterior cytopyge, one or more contractile vacuoles and an anterior concretion vacuole which some authors think is a statocyst. Cilia are uniformly distributed over the body or are restricted to certain areas. This family includes a number of genera and species, the great majority of which occur in the cecum and colon of equids. One genus, however, is found in the rumen of cattle and camels.
The body is ovoid, with a truncate anterior end and a rounded posterior end. There is a circular cytostome at the anterior end, but no cytopyge. The body is uniformly ciliated except for long cilia surrounding the cytostome. The ectoplasm at the anterior end is thick. The macronucleus is spherical.
Buetschlia parva Schuberg, 1888 is 30 to 50 u long and 20 to 30 u wide. B. neglecta Schuberg, 1888 resembles B. parva, but its posterior end is somewhat pointed and has 4 indentations, so that it looks like.a cross in cross section; it measures 40 to 60 by 20 to 30 u. B. lanceolata Fiorentini, 1890 is lanceolate, with a collar-like stricture in the anterior fifth of the body; it measures 48 by 20 u. These species all occur in cattle but are apparently not common, at least in the United States. Becker and Talbott (1927) did not find them in 26 cows they examined in Iowa. B. nana Dogiel and B. omnivora Dogiel are found in the rumen of the dromedary.