Tapeworms
Tapeworms are mostly parasitic flatworms that live in the intestines of mammals. Tapeworms could also grow to great lengths up to 30 feet.
Tapeworms are bilaterally symmetrical. Some consist of one long segment; others have a definite head, followed by a series of identical segments called proglottids. The head, or scolex, bears suckers and often hooks, which are used for attachment to the host. The body covering is a tough cuticle, through which food is absorbed. There is neither a mouth nor a digestive tract. Tapeworms also lack a circulatory system and an organ specialized for gas exchange. Since most tapeworms are parasitic it has no use for a nervous system and so it has mostly if not completely lost its nervous system.
Tapeworms are bilaterally symmetrical. Some consist of one long segment; others have a definite head, followed by a series of identical segments called proglottids. The head, or scolex, bears suckers and often hooks, which are used for attachment to the host. The body covering is a tough cuticle, through which food is absorbed. There is neither a mouth nor a digestive tract. Tapeworms also lack a circulatory system and an organ specialized for gas exchange. Since most tapeworms are parasitic it has no use for a nervous system and so it has mostly if not completely lost its nervous system.