Contribution of electron microscopic studies to the biology and classification of parasitic cestodes (review article).

Members of phylum Platyhelminthes are leaf-like or tape-like worms. Class Cestoidea are exclusively parasitic organisms; covered with a nonciliated integument; ciliated epithelium, when present, confined to embryos (onchospheres) hatched from eggs; scolex provided with suckers and frequently hooks for attachment to host tissue; body in most species divided into separate, sexually complete proglottids. Class: Cestoidea: comprises two subclasses: Cestodaria body undivided; only one set of reproductive organs; oncosphere hatching from egg has 10 hooklets. Cestoda: body typically with scolex and series of proglottids, each with one set (rarely 2 sets) of male and female organs; oncosphere typically has 6 hooklets (Beaver et al., 1984).