Tapeworm adhering to background support, from teaching collection, c. 1930s.
YPM catalog no. 47945
are parasitic flatworms that, as adults, live in the digestive cavity
of their hosts. As the name implies, they are long ribbon-like
organisms and can grow to lengths exceeding 15 feet (5 meters) in
humans. Amazingly efficient parasites, tapeworms have no need for a
digestive system of their own; instead they simply absorb nutrients
from their host's intestinal contents directly through their body wall.
People acquire tapeworms from eating undercooked meat or fish that
contains the juvenile stage of the parasite.
This tapeworm (above) has been meticulously affixed to a background to show the development of the body. The segments are continually added near the tiny head. Farther along they steadily increase in size and grow into larger egg-bearing segments. Tapeworms are part of a group of animals known as Platyhelminthes, which also includes flatworms. They are very distant relatives of the common earthworm.