关键词: 卫氏并殖吸虫, 超微结构, 焰细胞, 纤毛, 扫描电镜, 囊细胞, 毛蚴, 排泄管, 壁表面, 肌肉层

Abstract: Under SEM, the surface of the miracidium is densely covered with long and thin cilia. TEM shows that microtubules of the cilium are arranged in a typical form of "9 + 2". A layer of cytoplasmic projections was seen on the surface of the miracidium. Below the surface are matrix, basal plasma membrane and muscular layer consisting of srcular and longitudinal muscles. Therc is a large vesiculated cell containing numerous vesicles, lying beneath the muscle layer. Excretory system includes two flame cells, thcir size being 5.4/μm by 3.0/μm, with tiny cxcrctory tubes, the diameter of the tube cavity being about 0.4μm. The cilium bundle of flame cell is composed of about 39 to 45 cilia structurally similar to those on the surface of the body wall. Germinal cells gathering in groups are mainly distributed in the posterior and middle regions of the body.