Comparative ultrastructural observation of the cuticle and muscle of an enchytraeid (Enchytraeus japonensis) and an oribatid species (Tectocepheus velatus) using transmission electron microscopy

We observed internal tissue of wet soil meso animal, Enchytraeus japonensis and dry soil meso animal, Tectocepheus velatus using optical and transmission electron microscopes. Thin cuticle layer and thick epidermis covered the whole body, and there were epidermal gland cells of various forms in the cuticle of E. japonensis. The epidermis was formed of the bilayer, and thick body wall muscles of various travels were observed in the hypodermic. There were many lipid droplets (large and small size) under body wall muscles. On the other hand, the mite body of T. velatus was surrounded by thick sclerites. The sclerites formed a thin epidermis (outer layer), a thick epicuticle (middle layer) and a thick procuticle (inner layer). The procuticle was formed of 5-6 thin layers. However, there was the position with the impossible discriminate in other place. The hypodermic muscles were connected to the procuticle, and were surrounded by many lipid droplets. There were lipid droplets (large and small sizes) in various places. This study indicates that there are internal histological differences of soil animals according to different habitat and environment in soil.