STRUCTURE AND TEM ULTRASTRUCTURE OF THE EXCRETORY SYSTEM OF THE CERCARIA AND DAUGHTER SPOROCYST OF DIPLOSTOMUM PSEUDOSPATHACEUM NIEW, 1984 (DIGENEA, DIPLOSTOMIDAE)

The general morphology of the excretory system of the cercaria and dau ghter sporocyst of D. pseudospathaceum is described. The ultrastructur e of the following parts was examined: in the body - the filtering com plex, anterior and posterior collecting tubules, main collecting duct, main excretory tube, and excretory bladder; in the tail - the capilla ries with filtering complex, collecting tubes, main caudal duct, and f urcal duct. Differences in the morphology of the excretory system of c ercaria and daughter sporocyst are discussed: they relate to the lack of a main collecting tube and excretory bladder, and to the presence o f separate excretory pores in the sporocyst. The ultrastructure of the filtering complex of sporocysts differs in the more numerous cilia an d the presence of internal leptotriches. The other difference is the p resence of long cytoplasmic projections that are in contact with adjac ent cells in the distal part of the sporocyst capillary cell.