Nematocida is a genus of Microsporidia fungi. One species, N. parisii, is found in wild isolates of Caenorhabditis elegans. It has been knicknamed the nematode-killer from Paris. This species replicates in the intestines of C. elegans. is a cuticle that includes fibers such as keratin, collagen, and some that run around in opposite directions from each other. This has a flexible extracellular exoskeleton structure that has many layers, (but is very stiff) and that has a barrier that helps prevent nematodes from natural and ecological harm that may happen. These may have powerful agents that are used to recognize, attach, penetrate and kill theses parasitic nematodes.