Amphileptus (am-fee-lep-tus) pleurosigma. The body of the members of the genus Amphileptus is laterally compressed and elongate. The oral aperture is a slit on the convex edge of the neck region, and extends less than halfway down the body. Ciliation is present on both lateral surfaces although there is a tendency to some reduction on the left surface. Ciliation on the right surface is extensive and forms longitudinal rows which converge on each other in the anterior region. Trichocysts are common - particularly in neck. Macronucleus in 2 to 4 spherical parts with single micronucleus placed between macronuclei. Many contractile vacuoles occur along both dorsal and ventral edges. Lives in fresh water ponds and lakes. Free swimming specimen of Amphileptus pleurosigma. The two macronuclei and the contractile vacuoles located at the edges are visible. The S-shaped body and the neck-like anterior end are characteristic. Measuring 228 microns. Differential interference contrast.