Cyclophyllidea

Cyclophyllidean tapeworms have four circular suckers around the scolex. Some species also have hooks on the suckers, and these species are said to be ‘armed’. They also consist of a short unsegmented neck and a chain of segments. Most cyclophyllidean species live in the small intestine. New segments bud off from behind the scolex. These do not have an alimentary tract, but absorb nutrients across the body surface. This is covered by a tegument which is like that as for trematodes, but has a microthrix (minute finger-like projections) to increase surface area. Below the tegument are muscle cells and the parenchyma – a syncitium of cells, which fills the space between the organs. The nervous system consists of ganglia in the scolex, from which nerves enter the strobila. The excretory system is composed of flame cells leading to efferent canals, which run through the strobila to discharge at the terminal segment.