中文摘要：

为查清沙蜇大量暴发的原因，采用黄海北部的沙蜇亲体进行自然受精获得了数百万的螅状体，除海月水母和发形霞水母在消化腔和雌体的性腺中完成受精外，上述其余种类均为体外受精，霞水母属的2个种类的浮浪幼虫在形成螅状体前先形成一个具角质的浮浪体囊，沙蜇、海蜇、黄斑海蜇和Stomolophusmeleagris螅状体繁殖新螅状体的唯一无性繁殖方式是足囊繁殖，霞水母可通过足囊和由匍匐茎形成囊胞两种方式繁殖新螅状体，海月水母似．aurita）螅状体繁殖新螅状体的的无性繁殖方式包括足囊繁殖、出芽生殖、匍匐茎生殖、纵向分裂、内繁殖体和外繁殖体生殖，同时有直接发育现象，Rhizostomapulmo的无性繁殖方式有足囊，出芽生殖，匍匐茎，浮浪体芽。

英文摘要：

To clarify the causes for the mass occurrences ofNemopilema nomurai, the multi-million scyphistomae were obtained by natural fertilization, using N. nomurai as parent body from the northern Yellow Sea. The stages ofN. nomurai from planula, scyphistoma, strobila and ephyra to young medusa were observed under laboratory conditions, the life cycle of N. nomurai was compared with earlier findings of the life cycle of C. nozakii, C. capillata, A. aurita, Rhopilema escu- lentum, R. hispidum, Rhizostoma pulmo and Stomolophus meleagris. For A. aurita and C. capillata medusae, fertilization occurred in the gastrovascular cavity and gonad of female, others of them in the water. Planulae of C. nozakii could form planulocysts prior to forming a scyphistoma. C. nozakii and C. capillata could produce podocysts and a stolon, However, N, nomurai, R. esculentum, R. hispidum and S. meleagris, and N. nomurai （Kawahara et al, 2006） only produced one type of cysts： podocysts. In addition the scyphistoma of A. aurita might further produce polyps by producing podocysts, direct buding, formation of stolon, longitudinal fission, internal production of free-swimming propagules, extemal production of free-swimming propagules and direct development from planuta to single ephyra. The asexual reproduction of Rhizostoma pulmo included producing podocysts, buding, formation of stolon and planuloid buds.