The body is piriform, with 2 nuclei near the anterior end, and 6 anterior and 2 posterior flagella. The body is quite symmetrical, 3 anterior flagella and 1 posterior one arising on each side. There are 2 axostyles which originate at the anterior end and fuse as they pass posteriorly, emerging as a single central rod from the middle of the posterior end. This genus differs from Hexamita, of which it was formerly considered a synonym, in the structure of its axostyles (Gabel, 1954).
Octomitus pulcher (Becker, 1926) Gabel, 1954 (syn., O. intestinalis) occurs in the cecum of the Norway rat, house mouse, golden hamster, ground squirrels and other wild rodents. It measures 6 to 10 by 3 to 7 u.
These are free-swimming protozoa with a more or less rounded, bilaterally symmetrical body and with a cytostomal groove on each side of the posterior half. There are 8 flagella, of which 1 long and 3 short ones are present on each side. A horseshoe-shaped structure near the anterior margin contains the 2 nuclei. Members of this genus are free-living in fresh water, coprophilic or parasitic in amphibia, fish and turtles.
Trepomonas agilis Dujardin, 1841 occurs in stagnant water and the intestine of amphibia and is also coprophilic. It is 7 to 25 u long and 2 to 15 u wide, with a flattened body and with the posterior end wider than the rounded anterior end. The flagella come off near the middle of the body at the anterior end of the cytostome.