(locks-o-file-um) is one of several genera of flat gliding predatory ciliates. It glides along the substrate, exploring detritus with the anterior convex margin - which is where the mouth is located. There are rod-shaped extrusomes lying just under the cell membrane and in some species in prominences along the margins of the cell - not well developed in this cell. The extrusomes can be discharged to kill potential prey - usually other ciliates. Phase contrast.