Tissue Organization of the Male Reproductive System of the Acanthocephalan Acanthocephalus tenuirostris (Palaeacanthocephala, Echinorhynchida)

Histological and electron microscopic studies of the male reproductive system of the acanthocephalan Acanthocephalus tenuirostris show that its organization and structure are generally similar to those characteristic of representatives of the class Palaeacanthocephala. In its composition, paired testes with vasa efferentia, which are combined into a common vas deferens, six cement glands, Sefftigen’s pouch, a copulatory bursa, and a penis are identified. The distal part of the vas deferens, Sefftigen’s pouch, the bursa, and the base of the penis are surrounded by the genital sheath. The shells of the organs of the reproductive system are shown to be formed by fragments of muscle tissue immersed into fibrous intercellular material, which most likely is a derivative of muscle tissue. The most powerful muscle bundles were found in the genital sheath. It appears impossible to confirm the existing opinion concerning the symplastic organization of the organs of the reproductive system in male acanthocephalans.