Introduction

• Commonly known as roundworms, nematodes are a group of worms that make up the phylum Nematoda. Nematodes (from Greek nema a thread) are long, thin often threadlike “worms” with a thick cuticle.
•  The head is small and possesses only small sense organs and the overall appearance is of an organism that narrows at both ends mentioned by (Rafferty, 2019). With well over 15,000 species identified today, they can be found in different habitats ranging from terrestrial to marine environments. 
• Nematodes exist as free living organisms in terrestrial and aquatic environments or as parasites of both plants and animals. 
• Nematodes are one of the simplest animal groups to have a complete digestive system, with a separate orifice for food intake and waste excretion, a pattern followed by all subsequent, more complex animals. 
• The mouth is often surrounded by various flaps or projections used in feeding and sensation. The portion of the body past the anus or cloaca is called the "tail." 
• The epidermis secretes a layered cuticle made of keratin that protects the body from drying out, from digestive juices, or from other harsh environments, as well as in some forms sporting projections such as cilia that aid in locomotion. Although this cuticle allows movement and shape changes via a hydrostatic skeletal system, it is very inelastic so does not allow the volume of the worm to increase. Therefore, as the worm grows, it has to moult and form new cuticles.