The nematoda (roundworms or threadworms) are a group of helminths (worms) which have an un-segmented cylindrical body which tapers at both ends. They are found in water, in damp earth, and in decaying animal and vegetable matter. Nearly all the nematodes are parasitic all their lives, others are free as larvae, and parasitic as adults. Nematodes are without any respiratory or vascular system, but the sexes are usually separate, the female being larger than the male. Nematodes are responsible for a number of diseases, including worms in dogs, strangylus in horses, cattle and sheep, gapes in poultry, trichina in pigs. Other varieties are responsible for certain diseases which affect cultivated crops such as ear-cockles in corn. Research Nematode