Nematomorpha

Horsehair Worms in Illinois - Short article about phylum Nematomorpha, the group of invertebrates more commonly called horsehair or gordian worms. Includes a photo.
http://www.inhs.uiuc.edu/chf/pub/surveyreports/mar-apr95/page4.html

Nematomorpha - Information from Wikipedia on this phylum of free-living worms with parasitic larvae that are morphologically and ecologically similar to nematodes.
http://en.wikipedia.org/wiki/Nematomorpha

Ben Hanelt's Gordian Worm Information - Discusses the distribution and life cycle of freshwater nematomorphs (Phylum Nematomorpha). Includes images and videos.
http://bsweb.unl.edu/labs/janovy/ben/info.html

Gordiacea: Horsehair Worms - Photograph of these worms, also known as cabbagehair, gordiid or gordian worms, with information on their habitat, identification and life cycle.
http://www.ento.okstate.edu/ddd/insects/horsehairworms.htm

Gordius spp: Horsehair Worms - Photograph and description of these long, slender worms, with information on their distribution, life cycle and importance.
http://entnemdept.ifas.ufl.edu/creatures/misc/horsehair_worms.htm