Acineria incurvata  

Body approximately oblong in shape, 45-200 µm long, slightly contractile, laterally flattened, rounded posteriorly, narrowing anteriorly to a blunt point.  Rather variable in shape (slender to  plump) depending on nutritional condition.  Lower surface somewhat convex, upper surface straight or concave in the anterior, convex in the posterior region.  Anterior left edge rolled up to form a conspicuous spoon-like structure.  Anteriormost part of left (dorsal) edge somewhat refractive due to the rolled-up mouth.  Two spherical to ovoid macronuceli with a single micronucleus between them.  Single terminal contractile vacuole.  Pellicle soft, flexible, with longitudinal furrows in which the cilia and bristles originate.  Furrows disappear in well-fed individuals.  Carnivorous, feeds upon small hymenostome ciliates, e.g.  Colpidium, Cyclidium, Glaucoma, Pseudocohnilembus, Loxocephalus, and Uronema.