Nematode morphogenesis: fine structure of the cuticle of each stage of the nematode, Panagrellus silusiae (de Man 1913) Goodey 1945.

Abstract

The fine structure of the cuticle of each of the five stages of the free-living nematode Panagrellus silusiae (de Man 1913) Goodey 1945 has been examined. The cuticle plan is made up of a few regions: (1) an outer region (~350 Å) which consists of three layers: a thin outer layer, an electron transparent layer, and a thin but diffuse inner layer; (2) an inner region which has virtually no resolvable substructure other than a striated layer. This layer is not usually seen in the early stages of development but is readily apparent in the L4 and adult stages. The pattern of the cuticle is the same for each stage.The lateral fields—alae—reveal a definite differentiation during the life cycle; in the larval stages they are mere bulges but in the adults they take on a distinct four-lobed shape. The cuticle lining the pharynx consists of two regions, and there is never a striated band present nor does the cuticle increase in width during nematode growth.The interchordal hypodermis is devoid of endoplasmic reticulum, Golgi material, and mitochondria, but in some regions glycogen is found.