Tetmemena pustulata is a fresh water ciliate approximately 150 micrometers in length, dorso-ventrally flattened with an asymmetrical arrangement of cortical structures. The oral apparatus of this organism is composed of an adoral zone of membranelles and two undulating membranes plus an inconspicuous cytostome (cell mouth) located near the posterior end of the AZM. Ventral cirri are composed of hexagonally packed ciliated basal bodies. These cirri are ultrastructurally very similar to one another, differing only with respect to number of basal bodies comprising each structure. Marginal cirri, located at the left and right margins of the cell, are similar to the cirrus types described above. This is an SEM of the ventral surface of a dividing Tetmemena pustulata magnified 600 times.