The fine structure of adult Onchocerca volvulus. I. The cuticle, the hypodermis and the muscle cell of the male worm.

The fine structure of the cuticle, the hypodermis and the muscle cells of five male worms from Liberia and of two male worms, at least five years old, from Upper Volta is described. The cuticle in the lateral regions is thicker and consists of more layers than in the dorsal and ventral regions. The innermost zone of the hypodermis contains a wide labyrinth of extracellular clefts. The muscle cells are of the shallow coelomyarian type. Bacteria were found in the hypodermis of worms from Liberia and Upper Volta. The hypodermis and the muscle cells contained various other inclusions and particles. Some of them were formed by aggregations of regularly arranged membranes and lamellae. Although all the worms had been alive at the moment of fixation, severe degenerative alterations of the hypodermis and the muscle cells could be observed. Only the cuticular morphology was more or less constant in all seven worms.