The tapeworm actually consists of many white segments, joined together like a tape. They tape together and can get to be several feet long. Then they drop off to multiply. It is the segments that are seen as they shed. These segments contain the eggs, they look like wiggling grains of rice.
They are small so they can feed on their host with no problem and can reproduce in little space.
Because they are parasitic, they do not need a digestive system. Their host does it all for them so nutrients can be absorbed directly through the body walls.