Class Trematoda


Major Attributes:

  1. Almost exclusively endoparasitic.
  2. Bilaterally symmetrical.
  3. Specialized suckers for attachment to host.
  4. Flame cells for excretion.


While a few trematodes are exoparasitic, most are endoparasitic. They are simple organisms with a gastrovascular cavity, flame cells for excretion and a nervous system with no special sense organs. One or more well-developed suckers are used to cling to the host organism. A cuticle-like tegument protects trematodes from digestive enzymes and antibodies that are present in the host. The life cycle of these parasites is extremely complicated, generally involving egg and several larval stages and utilizing an array of hosts. Reproduction is sexual.

Some Interesting Facts:

Some Pertinent Books Found in Lamson Library:

  1. Marshall, A.J. and W.D. Williams. 1972. Textbook of Zoology: Invertebrates. NY: American Elsevier.
  2. Smyth, J.D. 1966. The Physiology of Trematodes. San Fransico: W.H. Freeman and Company.

Lab Assignment:

(Neil D. Breault) (Edited by Betty Miller, Spring 1995)