Class Phasmidia is a group of elongated nematodes that possess a specialized sense organ at their anterior end called the amphid. Synonyms for this class include the following: rhabditids, Strongyloides, Trichocephalus, and filarids. Rhabditids are soil-dwelling nematodes that are known for their easy culturing in the laboratory. Strongyloides are parasitic nematodes that can infect humans and animals, causing diseases such as strongyloidiasis and hookworm disease. Trichocephalus are intestinal parasites that infect mammals, including humans. Lastly, filarids are a family of parasitic nematodes that can cause diseases such as elephantiasis and river blindness. Despite their diversity, all of these synonyms refer to nematodes that belong to the Class Phasmidia.