Morphology of Free-Living Nematode

Abstract

Free-living marine nematode is a kind of small invertebrate, which lives in marine benthic sediments. It is generally a small, nonsegmented, unisexual animal with thread-like body. The body consists of an external cylinder and an internal cylinder. The external cylinder is the body wall consisting externally of a cuticle layer and internally of a longitudinal muscle layer. The internal cylinder is the digestive system, which is terminal at the anterior but subterminal posteriorly, that’s why nematodes have a tail. The digestive system is differentiated into a buccal cavity, a muscular pharynx, an intestine and a short rectum. Between body wall and digestive system lies a fluid-filled cavity called a pseudocoelom which contains a number of cells and other organs, such as the reproductive tract (Platt and Warwick 1988; Warwick et al. 1998; Decraemer et al. 2014).