[目的 ]比较福建拟钉螺与建瓯洱海螺体内逸出的并殖吸虫尾蚴 (A)与类似并殖吸虫尾蚴 (B)。 [方法 ]光镜观测并殖吸虫尾蚴与类似尾蚴 ,并感染溪蟹等。[结果 ]发现福建拟钉螺和建瓯洱海螺体内并殖吸虫尾蚴感染率分别为0 .2 % (8/ 5 2 83)和 0 .4% (2 6 / 6 2 2 7) ,类似并殖吸虫尾蚴的感染率分别为 2 .7% (140 / 5 2 83)和 2 .8% (175 / 6 2 2 7) ,并殖吸虫尾蚴平均 2 2 9μm× 88μm,类似尾蚴约为 189μm× 6 8μm。并殖吸虫尾蚴清晰 ,类似者模糊 ,尤以 7对穿刺腺为著。并殖吸虫尾蚴排泄囊前凹陷呈倒三角形 ,而类似者为“丫”或“r”型。并殖吸虫尾蚴感染率低于类似者。并殖吸虫尾蚴感染溪蟹可获囊蚴 ,而类似者则不能。 [结论 ]在福建拟钉螺和建瓯洱海螺体内发现的斯氏并殖吸虫尾蚴和类似吸虫尾蚴 ,虽然形态近似 ,但大小及结构等不同点可资鉴别 [Objective] To compare the cercaria parasite (A) and the cercariae of Paragonimus westermani (B) that were found in the spirochetes of Fujian Provincus and Jian’er Erhai. [Method] The cercariae of Paragonimus and cercariae of cercariae were observed with light microscope and infected with crabs and crabs. [Results] The prevalences of cercariae of Paragonimus westermani in Fujian Provincus and Jian’er Erhai were 0.2% (8/5283) and 0.4% (26/62), respectively, The infection rates of C. cercariae were 2.7% (140/5283) and 2.8% (175/6277), respectively. The average cercariae of C. cercariae were 292 μm and 88 μm respectively, and the cercariae were about 189 μm × 6 8 μm. Paragonimus and cercariae clear, similar to the fuzzy, especially in 7 on the puncture gland. Clostridium cercaria discharge pouch before the depression was inverted triangle, and similar to “Ah” or “r” type. Paragonimus infection rate is lower than similar. Paragonimus cercariae infection crabs can be metaplasia, and similar can not. [Conclusion] The cercaria parasitoid Schistosoma and cercariae cercariae which were found in Fujian snail and Jian’er Erhai snails were similar in size but different in size and structure