The Collaborative International Dictionary of English v.0.48:

Endoparasite \En`do*par"a*site\, n. [Endo- + parasite.]
   (Zo["o]l.)
   Any parasite which lives in the internal organs of an animal,
   as the tapeworms, Trichina, etc.; -- opposed to
   ectoparasite. See Entozo["o]n. -- En`do*par`a*sit"ic,
   a.
   [1913 Webster]

WordNet (r) 3.0 (2006):

endoparasite
    n 1: any of various parasites that live in the internal organs
         of animals (especially intestinal worms) [syn:
         endoparasite, entoparasite, entozoan, entozoon,
         endozoan]