ABSTRACT
The body wall of nematodes is composed of the cuticle, an underlying cellular/syncytial layer (the epidermis or hypodermis), and the longitudinally oriented somatic musculature. Classically the cytoplasmic layer underlying the cuticle has been called the hypodermis. However, Hyman (1951) and De Coninck (1965) referred to this layer as the 'epidermis' and Lee (1977) suggested that, to be comparable to many groups of animals that possess a cuticle, especially the arthropods, the term 'epidermis' is probably more appropriate than 'hypodermis'. Whilst 'hypodermis' is etymologically correct it is phylogenetically erroneous (Wright, 1987). Support for the term 'epidermis' in preference to 'hypodermis' has been forthcoming from several authors (Coomans, De Coninck and Heip, 1978; Inglis, 1983; Bird, 1984a, b; Wright, 1987; Bird and Bird, 1991; Lorenzen, 1994; Bird and Bird, 1998; Blaxter and Robertson, 1998) but the term 'hypodermis' is still extensively used in the literature. Bird and Bird (1998) stated 'There is no reason why the Nematoda should differ in this respect from all other invertebrate groups where various authorities have used the term 'epidermis' for the region beneath the cuticle'. The term 'epidermis' will therefore be used in preference to 'hypodermis' in this chapter.
