[Further observation on the ultrastructure of the sporocyst of Schistosoma japonicum].

A further observation was conducted on the ultrastructure of mother sporocyst (Ms) daughter sporocyst in the brood chamber (b-Ds), migrating daughter sporocyst (mi-Ds) and daughter sporocyst in the liver tissue (1-Ds) of Oncomelania hupensis by scanning and transmission electron microscopy. There are 5 points worthy of mention here, namely: 1. A special structure, microvilli polymerizing cisterna, is found on the tegument of 52-day-old Ms branche in all directions and a tubule-like structure is connected to the matrix of the tegument. The significance of this structure may be dealt with the metabolism and transport of the parasite. 2. The tegumental spines appear on 52-day-old Ms. 3. The function of multilaminated vesicle in the tegument of 1-Ds may be associated with the turning over of the surface coat of the larvae and the compatibility between parasite and molluscan host. 4. Abundant alpha-glycogen granules and mitochondria appear in the cytoplasm of parenchyma cell of brood chamber of Ms and Ds. It is proposed that the parenchymal cells not only served as the filling material, but also serve as the nursing cells for the regulation of asexual reproduction of the sporocysts. 5. The orientation of muscle fibers of the head of the mi-Ds and narrow node region of 1-Ds shows a well development of the inner longitudinal fibers adjacent to the outer circular muscle layer. They run anteroposteriorly or vertically from the dorsal to the ventral. The pattern of muscle fibers may account for the activity of these regions of the parasite. (Figs 1-8).(ABSTRACT TRUNCATED AT 250 WORDS)