关键词: 异盘并殖吸虫, 囊蚴, 后尾蚴, 超微结构

Abstract: The surface ultrastructure of metacercariae of Paragonimus heterotremus was studied by scanning electron microscope. Encysted metacercaria was egg-shapped with a button-like structure on its end. The oral sucker of the newly excysted metacercaria was larger than the ventral sucker. Single-pointed spines were covered densely on all of the tegumental surface. There were two and three rings sensory papillae on the oral and ventral suckers, respec- lively. Six papillae of the most inner ring were distributed on the ventral sucker inner-pore symmetrically. A few sensory papillae were dispersed on each side of the anterior part of the worms. These papillae of some excysted metacercariae were arranged irregularly in two rows with 5 to 6 papillae in each row (Figs. 1-8).