THE STRUCTURE OF THE NAMATODE CUTICLE

摘要: The nematode cuticle is shown to consist, grossly, of three layers; an outer layer—the cortical layer, intermediate layerMdashthe matrix layer and inner basal layer. With these layers associated a punctation canal component. carries externally wholly sclerotized epi-cortex. part the modified as lamella for attachment hypodermis, from which it not sharply delimited, body musculature. component most prominent in members Chromadorida where responsible all patterns characteristic this Order. system consists columnar elements simplest forms, example Cyatholaimidae, series interlocking transversely fused units more complex, Euchromadora. In Desmodoridae similar “annulate” forms major appears be produced by transverse fusion canals. groups gross structure easily established demonstrated that same layering can identified throughout Nematoda. It modifications interpreted based on built around functional requirements are considered cuticular developed meet necessity anisometric flexible longitudinally strong radially. Thus, annulate desmodorids strongly patterned Euchromadora have been demands met such Ascaris, Enoplus, Mermis Dorylaimus development spirally arranged fibre layers. many the matrix plasticMdashthat is, distortedMdashwhile fairly rigid although probably elastic. high degree organization only massive elaboration occurring some but also birefringence argued amphids free-living marine act mechano-stretch receptors. suggestion advanced evolved originally method allowing grow incorporation additional materials processes hypodermis was later became basis moulting. inevitable consequences hydrostatic-skeleton: longitudinal muscle form discussed stressed characters diagnostic Nematoda functionally determined. Attention drawn opportunities must result convergence during evolution group difficulties introduces attempting classify