Cestoda

Cestoda is a class of parasitic flatworms in the phylum Platyhelminthes, commonly known as tapeworms. Most species belong to the subclass Eucestoda and take the familiar ribbon-like adult form built from repeating segments called proglottids, each essentially a packet of eggs shed to infect new hosts. Adult tapeworms live in the digestive tracts of vertebrate definitive hosts, lack a mouth, and absorb nutrients directly through their body wall, while larvae typically develop in one or more intermediate hosts. Around six thousand species have been described, and nearly all vertebrates can host at least one.