前言线虫体圆柱形,它们的种类和数量十分丰富,在农业土壤中,常占多细胞无脊椎动物区系组成的90％之多。一英亩的农业土地15厘米深的表土内就有万亿条线虫。大多数线虫似虫形,长1毫米以下。它们演化为不同的营养类型,如以细菌、真菌、高等植物、动物、甚至寄生于人体的营养类型。已知和已发表的线虫种类不到存在数的10％。世界上有很多陆地与水域,对这些有意义的动物种类尚未调查,它们数量之多在动物界 Introduction The nematodes are cylindrical in shape and abundance, accounting for as much as 90% of the multicellular invertebrate fauna in agricultural soils. There are trillions of nematodes in the 15 cm deep topsoil of an acre of agricultural land. Most nematodes are worm-shaped, less than 1 mm long. They evolve into different types of nutrition, such as bacteria, fungi, higher plants, animals, and even parasitic human nutrition types. Known and published nematode species less than 10% of the existing number. The world has a lot of land and water, for these species of animals have not yet been investigated, as many as the animal kingdom