Ascaris Dissection- This site from the University of Minnesota has a photograph of dissection of this common intestinal roundworm.
Phylum Nematoda- Animal Diversity Web, University of Michigan. Information on nematodes ranging from the dog intestinal roundworm to the nematode that causes onchocerciasis.
Society of Nematologists- This page contains much information on plant and parasitic nematodes. This home page has many links, news, images, research on nematodes, as well as the Nematode of the Week!