Taenia (flatworm) in the context of "Taeniasis"

Cysticercus (pl. cysticerci) is a scientific name given to the young tapeworms (larvae) belonging to the genus Taenia. It is a small, sac-like vesicle resembling a bladder; hence, it is also known as bladder worm. It is filled with fluid, in which the main body of the larva, called scolex (which will eventually form the head of the tapeworm), resides. It normally develops from the eggs, which are ingested by the intermediate hosts, such as pigs and cattle. The tissue infection is called cysticercosis. Inside such hosts, they settle in the muscles. When humans eat raw or undercooked pork or beef that is contaminated with cysticerci, the larvae grow into adult worms inside the intestine. Under certain circumstances, specifically for the pork tapeworm, the eggs can be accidentally eaten by humans through contaminated foodstuffs. In such case, the eggs hatch inside the body, generally moving to muscles as well as inside the brain. Such brain infection can lead to a serious medical condition called neurocysticercosis. This disease is the leading cause of acquired epilepsy.

In biology, a cirrus (/ˈsɪrəs/ SIRR-əs, pl.: cirri, /ˈsɪraɪ/ SIRR-eye, from the Latin cirrus meaning a curl-like tuft or fringe) is a long, thin structure in an animal similar to a tentacle but generally lacking the tentacle's strength, flexibility, thickness, and sensitivity.

In the sheep liver fluke, for example, the cirrus is the worm's muscular penis and when not in use is retained within a cirrus sac or pouch near the animal's head. The same structure exists in the various Taenia species of tapeworm. In the clam worms, however, the cirrus is the tentacular process or growth on each of the feet (parpodia), either the dorsal cirrus or the ventral cirrus, and has nothing to do with reproduction.