东海鳓卵巢发育的组织学观察

于光镜于对东海鳓卵巢切片作了组织学观察，结果表明，5月－7月为东海鳓的繁殖期，其卵巢在Ⅳ期、Ⅴ期、Ⅵ－Ⅳ‘期和Ⅴ‘期，8月－9月鳓卵巢处在产后休整阶段；10月－翌年2月为越冬Ⅱ期卵巢；3月－4月卵巢处在产前发育阶段，在小生长期，卵核的体积较核质的体积增大快，核质比大，大小长期，随着卵黄物质的积累，卵母细胞体积快速增加, 比下降。在鳓卵母细胞发育中，曾见有两层卵膜结构，但接近成熟的卵母仅有一层卵膜。东海鳓的产卵方式为短期分批产卵类型。在一个生殖周期内，一般产卵2次。

Observation on the ovary development of Ilisha elongata in the East China Sea

Observation on the ovary sections of Ilisha elongata ( Bennett) was taken. It shows that it s breeding season extends from May to July, during which period the ovary is variously found to be in stages . , . , .- . . and .. ( recovering) . In August and September, the ovary is in a stage of degeneration after spawning. From October to February of the following year, the w inter ovary is in stage ò . In March and April there is the prespawning spring ovary. In the course of development of oocytes of Ilisha elongata, the nucleus increases in volume more markedly than the cytoplasm during the small growth stage, but during the great growth stage, with the accumulation of yolk substances, the volume of the cytoplasm increases rapidly with a correspondingly sharp drop in the nucleus-plasma ratio, which approaches a minimum ratio as the oocyte approaches full maturity. In the development of oocytes, there are two layers of membrane outside the plasm membrane, but in the late stage of vitellogenesis the zona radiata of the oocytes degenerates, and there is only a layer of gluey membrane. Evidently the development of oocytes in the ovary of Ilisha elongata is in a successive process and female seems to be able to spawn twice in one spawning season.