Polarised light micrograph of a Difflugia sp. amoebae (left) and stentor protist (right) attached to a water boatmans leg (hairy substrate). Difflugia is the oldest and most species-rich genus of testate amoebae, comprising over 300 species. Stentor is a genus of large single celled pond filter-feeding ciliates with a distinct trumpet shape with remarkable regenerative powers. Water boatmen are aquatic freshwater bugs that propel themselves through the water using a pair of long legs. Magnification: 93x when printed 10 centimetres wide.