Bell-shaped Vorticella sp. ciliates forming a colony of several solitary unicellular animals captured with a microscope. Vorticella occurs in a broad bandwidth of freshwater and marine habitats including small brooks and ponds of any size. The single celled Individuals are campanulate and about 60x45 m in size with a long, contractile stalk, attached to underwater objects like plants, surface scum and aquatic animals. The stalk consists of an external sheath containing fluid and a contractile, spirally arranged thread. When disturbed, the stalk thread contracts very fast with the sheath coiled like a corkscrew.. Vorticella is a filter feeder feeding on bacteria or small protozoans. The species identification needs special staining techniques like silver impregnation. Microscopic contrast method : differential interference contrast. Captured field width : 0, 5mm.