Description of Acineta tuberosa
Suctorian ciliate, with a lorica that is flattened, subtriangular, widest at its distal margin, and tapers gradually towards its point of junction with the stalk. The lateral walls continue over the frontal border, but with two ovate apertures at the anterior corners which is where the tentacles emerge. The stalk is slender, and varies from equal to, to as much as four or five times, the length of the lorica. Body narrows posteriorly, rarely filling the cavity of the lorica except towards the anterior border, but the body always attaches to the lorica by its posterior extremity, in the region of the tentacles, and usually along four perpendicular lines extending from the posterior extremity towards the anterior border. The tentacles form two antero-lateral fascicles, extending through the ovate apertures in the lorica, but may also be retracted in a sheaf-like manner into the body. With one contractile vacuole , anteriorly located. Nucleus elongate-ovate or cord-like, often contorted and branched. Length of lorica 50.8-84.7 microns.