These specialized tapeworms are of no medical importance, but are a classic example of specialized morphological adaptations for attachment.
Definitive hosts are elasmobranch fishes but detailed life cycles are poorly known for this group. The cycle probably involves two intermediate hosts, with procercoids developing in a crustacean first intermediate host and plerocercoids developing in a fish or cephalopod second intermediate host.
These are small tapeworms, often only about 5 cm long. The most unusual feature of this group are the leaf-like or flap-like bothridia which emerge from the scolex of most species. The bothridia often have numerous loculi, but suckers and/or hooks are present instead in some species. Testes are located only anterior to the ovary, and the female genital pore opens anterior to the male genital pore.