The Collaborative International Dictionary of English v.0.48:

Tapeworm \Tape"worm`\, n. (Zool.)
   Any one of numerous species of cestode worms belonging to
   Taenia and many allied genera. The body is long, flat, and
   composed of numerous segments or proglottids varying in
   shape, those toward the end of the body being much larger and
   longer than the anterior ones, and containing the fully
   developed sexual organs. The head is small, destitute of a
   mouth, but furnished with two or more suckers (which vary
   greatly in shape in different genera), and sometimes, also,
   with hooks for adhesion to the walls of the intestines of the
   animals in which they are parasitic. The larvae (see
   Cysticercus) live in the flesh of various creatures, and
   when swallowed by another animal of the right species develop
   into the mature tapeworm in its intestine. See Illustration
   in Appendix.
   [1913 Webster]

   Note: Three species are common parasites of man: the pork
         tapeworm (Taenia solium), the larva of which is
         found in pork; the beef tapeworm (Taenia
         mediocanellata), the larva of which lives in the flesh
         of young cattle; and the broad tapeworm
         (Bothriocephalus latus) which is found chiefly in the
         inhabitants of the mountainous regions of Europe and
         Asia. See also Echinococcus, Cysticercus,
         Proglottis, and 2d Measles, 4.
         [1913 Webster]