The cement apparatus of larval and adult Acanthocephalus anguillae (Acanthocephala), with notes on the copulatory cap and origin of gland secretion

Light and electron microscopy were used to investigate the ultrastructure o f the cement apparatus, namely cement glands and cement ducts, of mature sp ecimens of the parasite Acanthocephalus anguillae (Muller, 1780) Luhe, 1911 recovered from the alimentary. canal of fish Leuciscus cephalus (Risso, 18 26), In addition, the cement apparatus of immature ii. anguillae found with in the body cavity of the crustacean Asellus aquaticus (L.) was examined. I n immature and mature males of Acanthocephalus anguillae, there are six rou nd cement glands and each of them has an outer cytoplasmic layer containing nuclei and surrounds a space for storage of the cement. The cytoplasmic la yer produces round, membrane-bound secretory granules approximately 1 mum i n diameter. Nuclei and other cellular organelles surrounded by secretory gr anules were noticed inside the luminal part of the gland of adult males. In some female Acanthocephalus anguillae, within the attached copulatory cap, eggs and spermatozoa were observed. A protein of about 23 kDa appeared to be the major component of proteins of isolated cement glands, as well as in detached copulatory caps.