Cysticercus

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.

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.

Hence, it was given a proper scientific name Taenia cellulosae in 1800 by German naturalist Johann Friedrich Gmelin.

[1][7] In the normal life cycle of Taenia, cysticerci develop in the muscles of the intermediate hosts such as pigs, cattle, and sheep.

Due to accidental consumption of the eggs from contaminated foodstuffs, cysticerci in humans produce clinical symptoms, cysticercosis.

Drawing of Cysticerus cellulosae : Left one from the pig showing an invaginated scolex. Right one from human intestine showing the evaginated scolex.
Resected gross specimen of cysicercus from the human brain, (a) and photomicrograph of hematoxylin and eosin stained section, (b) cysticercus cellulosae with an undulating bladder wall and scolex. Three suckers along with rows of hooklets (arrow) can be identified on the scolex (×200, original magnification)