Turbellaria (L. turbella - a string) is a class of phylum-Platyhelminthes. Turbellarians are mostly free, living flat worms, majorly aquatic (marine), presence of cilia, body unsegmented, mouth ventral, suckers absent with tango, chemo and photoreceptors. e.g., Planaria (Dugesid), Bipalium, etc. Trematoda (Gr. trema- hole; eidos-form), class of phylum-Platyhelminthes. Commonly called flukes, ecto or endoparasites, body without cilia, unsegmented with suckers and hooks, e.g., Fasciola, Schistosoma, etc. Cestoda (Gr. kestos, girdle; eidos, form) is also one of the class of phylum-Platyhelminthes. They are commonly called tapeworms parasites without cilia and sense organs body segmented (pseudometamerism), digestive system absent, e.g., Taenia and Echinococcus.