Ovarian development of Corynosoma semerme (Acanthocephala) during experimental infections in rats

The general structure and aspects of the development of the ovaries of the palaeacanthocephalan Corynosoma semerme were studied by transmission electron microscopy using worms varying in age from 18 to 90 h obtained from experimental primary infections in hydrocortisone-treated rats instead of seals, which serve as the natural definitive hosts. The observations can be interpreted to show that the immature ovaries become transformed relatively rapidly from cellular spheres to the more complex mature ovaries consisting of the supporting and oogonial syncytia and the germ-line cells. The supporting syncytium developed before the oogonial syncytium. The cytological appearance of ovaries from worms from rats was found to be similar to that of ovaries from mature worms of unknown age from naturally infected seals. Ecological evidence is considered to suggest that the rapid maturation of C. semerme in rats may also occur when the parasite becomes established in seals.