Vorticella venusta Nenninger 1948

Testate amoeba, lorica is pale yellow or hyaline, cylindrical; gradually swelling from the aperture for about two-thirds of the body length to the broadest diameter and then tapering sharply in the last third to the bluntly pointed apex. It is composed mainly of small to medium pieces of quartz and diatom frustules arranged to give a relatively regular, intermediate smooth outline apart from the occasional addition of a larger angular piece of quartz or diatom frustule. Small areas of organic cement are sometimes visible as a thick walled network with a covered mesh, but more often as thick walled rings about 450-600 nm in diameter and walls 150-220 nm. The aperture is usually circular and surrounded by small particles that give it an irregular margin. Body length 174-188 microns, breadth 68-76 microns, diameter of aperture 30-32 microns.