Class Turbellaria - Dugesia. Note eyespots, branched gastrovascular cavity, and pharynx.

 Class Digenea - Clonorchis sinensis, the Oriental liver fluke. Note prominent oral sucker, pharynx, gastrovascular cavities, ventral sucker, oviduct, ovary, vitelline glands, testes.

 Life cycle of Clonorchis sinensis. It, like other digeneans, follows a complex life cycle involving two intermediate hosts. The first intermediate host is a snail, in which the miracidium differentiates into a sporocyst. Eventually, cercariae will emerge from the snail and borrow into fish, especially carp, to form metacercariae in the muscle tissue. People become infected by eating inadequately cooked fish.

 Class Cestoda - Echinococcus granulosus. Unlike most cestodes, this one is only three segments long. The hindmost segment is gravid, with numerous ova. The definitive hosts for these tapeworms are dogs.

 Scolex of a tapeworm showing suckers, a prominent rostellum and at least 14 spines.

 Ovum of Hymenolepis diminuta, the rat tapeworm. Insects ingest the ova, and the cysticercoid larvae develop in the hemocoel. Rats acquire the infection by ingesting the insects. Occasionally, humans are reported infected with the rat tapeworm.