白色霞水母生活史的实验室观察

本文首次描述了白色霞水母从受精卵至碟状体的生活史。(1)包括受精卵、卵裂、囊胚以及浮浪幼虫等在内的胚胎发育各期均在开放的水体中,在20·8 -21·4℃浮浪幼虫于受精后14 h出现; (2)浮浪幼虫在定置前形成一种凸面的圆形浮浪幼体囊,除了浮浪体囊外,螅状体还可产生足囊和通过产生匍匐茎形成囊胞进而发育成新的螅状体; (3)尽管偶而产生2个碟状体但仍为典型的单碟型横裂; (4)新释放的碟状幼体绝大多数为8个缘叶, 8个感觉棍和8对钝圆的缘瓣,但畸形个体最多12个,最少6个缘叶; (5)雌雄个体间的交互作用对产卵和受精是非常重要的因子动物学报52 (2) : 389 -395 , 2006]。

Laboratory observations on the life cycle of Cyanea nozakii (Semeostomida, Scyphozoa)

The life cycle of the scyphozoan Cyanea nozakii Kishinouye was described from the fertilized-egg to the ephyra stage for the first time. (1) Embryogenesis from fertilized egg, cleavage of the zygote to blastula proceeded in the open sea water and planulae formed after 14 hours at 20.8 - 21.4℃. (2) Planulae formed plano-convex cysts(planulocysts)on attachment prior to forming scyphistomae. In addition to planulocysts, scyphistomae of Cyanea nozakii could produce podocysts and tendrils, which could also be involved in formation of new cysts and development of new scyphistomae. (3)Strobilation was typically monodiscous although strobilae liberated two ephyrae occasionally. (4) Newly liberated ephyrae had 8 marginal lobes, 8 rhopalia and 8 pairs of blunt-shaped lappets, aberrant specimens had maximum of 12 and minimum of 6 marginal lobes. (5) The interaction between mature individuals was important for spawning and fertilization Acta Zoologica Sinica 52 (2): 389 - 395, 2006].