This slide shows two stained specimens of the large, trumpet-shaped ciliate Stentor, a common inhabitant of freshwater lakes, ponds and streams.  Although Stentor can use its cilia to actively move through the water column in search of food, it is often found attached by a long stalk to submerged sticks, stones and vegetation where it uses an array of complex ciliary organelles to draw food particles into its mouth (cytostome).  Note the long, beaded macronuclei whose great size most likely reflect the special problems of controlling such a large cell.