Rohde, Klaus Department of Zoology, University of New England, Armidale, New South Wales, Australia.
- Links to Primary Literature
- Additional Readings
An order of large (several to many centimeters long) flatworms without proglottids (“unsegmented”) and intestine. Eight species have been found in the body cavity of freshwater and marine fishes, and of freshwater turtles. (The Cestodaria, in which they were formerly included jointly with the Gyrocotylidea, is probably not a valid taxon.) The known life cycles (of three species) include crustaceans (Amphipoda, Decapoda) as intermediate hosts. Final hosts become infected by eating intermediate hosts. Larvae are characterized by anterior penetration glands, two separate posterior nephridiopores (external excretory structure openings), and five pairs of polymorphic posterior hooks, which are retained at the posterior end of the adult (see illustration). Adults are hermaphroditic. Testes are scattered throughout most of the body; the ovary is located near the posterior end and opens into the uterus, which runs forward to near the anterior end, turns backward toward the posterior end, and then forward again to open through an anterior uterine pore. The follicular vitellarium (the part of the female reproductive system that produces nutritive cells filled with yolk) extends along much of the body margins. A muscular proboscis is located at the anterior end, and is sometimes very weakly developed or absent.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information