Ultrastructure of the eggs of Polymorphus magnus (Acanthocephala, Polymorphidae).

The ultrastructure of Polymorphus magnus acanthocephalan eggs has been studied. The eggshell consists of four envelopes that are morphologically similar to those of the eggs of other Palaeacanthocephala representatives. The studied acanthors are formed by the cortical syncytium and "central nuclear mass". In the anterior part of acanthors there is a penetration gland. Its secret may provide the larvae migration into intermediate host's organism. "Central nuclear mass" consists of several germinative nuclei and numerous fibrillar bodies, formed as a result of germinative nuclei degradation.