Any of various parasitic flatworms of the class Cestoda, having a long flat body that usually has a specialized organ of attachment at one end (the scolex). Cestodes may consist of a single segment or be divided into numerous identical rectangular segments. Food is absorbed through the outer covering of the body. Cestodes inhabit the liver and digestive tract of many vertebrate animals and also affect some invertebrates. They can attain a length of over 15 m (49 ft).