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 daughter sporocyst of D. pseudospathaceum is described. The ultrastructure of the following parts was examined: in the body - the filtering complex, anterior and posterior collecting tubules, main collecting duct, main excretory tube, and excretory bladder; in the tail - the capillaries with filtering complex, collecting tubes, main caudal duct, and furcal duct. Differences in the morphology of the excretory system of cercaria and daughter sporocyst are discussed: they relate to the lack of a main collecting tube and excretory bladder, and to the presence of separate excretory pores in the sporocyst. The ultrastructure of the filtering complex of sporocysts differs in the more numerous cilia and the presence of internal leptotriches. The other difference is the presence of long cytoplasmic projections that are in contact with adjacent cells in the distal part of the sporocyst capillary cell.