Platyhelminthes

Metagonimiasis - Information on the minute intestinal fluke, Metagonimus yokogawai, which can parasitize the human gut, and a diagram and information on its life cycle.
http://www.dpd.cdc.gov/dpdx/HTML/Metagonimiasis.htm

Flatworm: Procotyla fluviatilis - Photographs and information on these organisms.
http://fcps.edu/islandcreekes/ecology/flatworm.htm

Phylum Platyhelminthes - An introduction to the phylum with more pages about the Turbellaria, Monogenea, Digenea and Cestoda, from Animal Diversity Web.
http://animaldiversity.ummz.umich.edu/platyhelminthes.html

Introduction to the Platyhelminthes - Introduction to the Platyhelminthes, the flatworms: life in two dimensions. One page of text with a few photographs.
http://www.ucmp.berkeley.edu/platyhelminthes/platyhelminthes.html

Meiofauna - Matthew Hooge - A personal page with many beautiful photographs of free-living Platyhelminthes, including actin labelling.
http://hooge.developmentalbiology.com/

Fredrick the Flatworm - Information and images of different types of Platyhelminthes (flatworms). [Javascript required]
http://flatwormf.tripod.com/

Flatworms: British Marine Life Study Society - One page about a planarian and one page about the life cycle of the digenean Cryptocotyle lingua, with a few photographs.
http://www.glaucus.org.uk/planaria.htm

Schistosomiasis - Information on the digenetic blood trematodes of the genus Schistosoma which can infect humans, and a diagram and information on their complex life cycle.
http://www.dpd.cdc.gov/dpdx/HTML/Schistosomiasis.htm

Phylum Platyhelminthes - Brief illustrated description of this phylum.
http://www.meer.org/M31.htm

Platyhelminthes: Flatworms, Tapeworms, Flukes - Much information on the flatworms and the characteristics that distinguish them from other worm-like creatures, with photographs and diagrams.
http://www.discoverlife.org/20/q?search=Platyhelminthes

Platyhelminthes and Acoelomorpha: Phyla of Controversy - Illustrated article by Seth Tyler discussing the difficulty in correctly classifying the flatworms and the acoelomates.
http://devbio.umesci.maine.edu/styler/globalworming/platyhelm.htm