In biology, the class Cestoda, form the common tapeworms. The adult tape worms live in veterbrates. They have head called scolex with hooks and suckers for attachment. Posterior to scolex, they have proglottids (immature, mature, gravid) that contains numerous eggs. The proglottid is the sac of sex organs. Not having defined digestive tract, they absorb food predigested by the host, vetebrates.
Mature proglottids are released from mature tapeworm and leave the host with feces. For example, human feces contaminate the food of intermediate host, such as pigs or cattle, and the tapeworm eggs develop into larvae. Human can get larvae of tapeworms by eating uncooked meat. The large tapeworms can be 20m or longer and they can be harmful to humans sometimes.
There are two subclass in class cestoda, the Cestodaria and the Eucestoda. The all the animals we usually think of as tapeworms are in Eucestoda. The only a few species of unusual worms are in sub class Cestodaria.
