Objective To observe the development of Schistosoma japonicum in Oncomelania hupensis. MethodsOncomelania snails were infected heavily with miracidia of S.japonicum and the snails were dissected in different time. The mothersporocysts, daughtersporocysts and cercariae were collected, fixed with Bouin's fluid, dyed with carminic stain, enveloped with neutral gum and examined. ResultsThe neural rings were found in 1-24 hours old mothersporocysts and disappeared in 2 days. In the mothersporocysts, germinal cells increased and developed to germ balls. One germ ball developed to one daughtersporocyst. In daughtersporocysts, there were germ balls of different development stages and at last they developed into cercariae. ConclusionThe development process from the miracidium to mothersporocyst, to daughtersporocyst, to cercaria is observed.

Objective To examine the tegmental structure of Schistosoma nanjingi using scanning electron microscopy. Methods Adult schistosomes were obtained from infected rabbits with cercariae shedding from Oncomelania snails, which were infected with miracidia of Schistosoma nanjingi. The adult schistosomes were fixed with 4% glutaradehyde, and then, the samples were prepared with the conventional procedures and the schistosomes were examined with a scanning electron microscope (SX-40). Results There were two types of male and female adult worms. For the big male worm, there were big spines and deep cavity on the surface of middle back and some small spines on the surface of middle abdomen; for the small male worm, there were many small spines on the surface of whole back and abdomen. As the big female worm, there were some small spines on the whole tegumental surface. As the small female worm, there were some small spines on the surface of back and abdomen, but the shape of spines was different between the spines of back and abdomen. On the tail surface of the small female worm, there were two types of spines. The spoke-like acetabulum was found. The sensory organelle papillae with or without cilia were found on the tegmental surface of both male and female woems. Conclusion The tegmental structure of Schistosoma nanjingi is much different from that of Schistosoma japonicum.