Metopus minor

Ciliates, 30-40 microns long. The cells have three groups of long cilia and a conspicuous, protruding anterior lobe. The three groups of long cilia are located as follows: one group is at the front of the cell (when the organism is seen from the side), just above the tip of the frontal lobe; one group is opposite the latter, at the anterior part of the dorsal surface; and finally, there is one group of (usually) five, long, caudal cilia. The ciliate uses these three groups of cilia to attach to sediment particles, where it is normally observed filter feeding. The cells have five or six somatic kineties with only a few cilia in each kinety (as seen with Nomarski interference contrast- silver impregnation was not feasible due to the small number of specimens found). The single macronucleus is ellipsoidal, and is placed in the anterior half of the cell. The single micronucleus lies next to it. The contractile vacuole is situated at the posterior end of the cell.