(co-thur-knee-a) is a sessile peritrich ciliate. The cells live within a lorica which is itself stalked. Cells attach to the base of the lorica by the posterior ends of the cell. Cells can contract into the lorica. The oral cilia form a wreath around the anterior end of the cell. One of the peritrich ciliates, distinguished by having a wreath of cilia around the anterior of the cell. Normally feeding on bacteria. No cilia on the body. Phase contrast.