ULTRASTRUCTURE OF THE MALE REPRODUCTIVE-SYSTEM IN A RUMEN AMPHISTOME COTYLOPHORON-COTYLOPHORUM

The ultrastructure of various regions of the male reproductive tract a nd the prostate gland of Cotylophoron cotylophorum (Trematoda: Digenea ) is described. The internal lining of the entire male duct system is syncytial in nature, and regional variation is quite evident. The sync ytial epithelium of the vas deferens and seminal vesicle is very thin, flat and lamellate and the lumen is packed with spermatozoa. In the p ars musculosa (PM) the syncytium is also flat but lamellae are sparsel y distributed and anastomosed at places to form loops. The syncytium o f the PM is invested by several layers of circular and longitudinal mu scle. The pars prostatica (PP) is lined by an uneven but moderately th ick syncytial epithelium with nuclei projecting into the lumen. The sy ncytium bears numerous very long lamellae. The ejaculatory duct epithe lium is devoid of lamellae. It is even and moderately thick throughout . The prostate gland cells are uneven in outline and bear long ducts w hich open into the lumen of the PP. They show an ultrastructural organ ization suggestive of protein secretion.