The fine structure of adult Onchocerca volvulus. V. The digestive tract and the reproductive system of the female worm.

The morphology of the oesophagus, the intestine, the ovary, the uterus, the vagina and some inclusions in the body cavity are described in worms of different ages. The oesophagus wall comprises mostly muscle fibrils and a few glandular regions located only in the posterior portion. In the lumen, some material was found. From the anterior to the posterior end, the lumen of the intestine is reduced. The plasm of the intestinal cells of older worms is filled with concentric spherules containing iron, which are absent in mature but not full-grown worms. The ovarial cells contain in their outer region some fibrils and in the inner region some dense bodies. The ring-muscles of the uterine wall run in clefts of the basal lamina. They usually have accumulated iron containing bodies. In the final portion of the uterus and in the vagina the muscles are very thick. A comparison of the general morphology of the midbody regions of young, not full-grown worms, one less than five years old worm and some worms at least five years old is given.