半滑舌鳎胚胎发育及稚鱼变态过程观察

利用显微镜对半滑舌鳎胚胎发育及稚鱼变态过程进行连续观察，对各个时期的发育时间进行了记录，并对不同时期的特征用进行了拍摄。结果表明：半滑舌鳎成熟卵子呈球形，为多油球浮性卵。受精卵培养在水温21．6—22．8℃，pH值7．0～8．2。盐度30的海水中，历时39h仔鱼孵出。与其他硬骨鱼类基本相似，半滑舌鳎胚胎发育属于盘状卵裂，发育过程可分为：受精卵、卵裂期、囊胚期、原肠期、神经胚期、器官分化期、出膜期和初孵仔鱼。仔鱼孵化出膜进入胚后发育阶段，之后进入变态期，向成鱼转化。与牙鲆、大菱鲆等鲆鲽鱼类不同，半滑舌鳎稚鱼变态初期是在头顶两眼前上方形成一个横裂，右眼由此横列穿过，最终到达身体左侧，此后横裂逐渐愈合，变态完成，该过程历时3-4d，其形成机制有待进一步深入研究。

Study on the embryonic and larva metamorphosisdevelopment of Cynoglossus semilaevis

The total development stage of was Cynoglossus semilaevis noted and calculated and the charac- teristic images were taken using Olympus camera.The results showed that the egg of the tonguefish was separate, spherical and buoyant. Under the culture temperature of 21.6-22.8℃, pH 7.0-8.2 and salt 30 , the eggs began to hatch in 39 hours after fertilization.The major embryonic development stages of was as follows：lastodisc forming stage post fertilization; four cell stage; momla;low blastula stage ; early gastrula stage;late gastrula; blastopore closing stage;numla stage; embo-movement;pre-hatching stage;hatching stage.Yolk sac was completely absorbed after fertilization and then entered metamorphosis stage. Different from other Pleuronectiformes, the proceeding of metamorphosis was following： a channel was formed in front of two eyes and right eye went to left side thought this channel and then it healed little by little. Its mechansim was worthy to be further researched.