日本新糠虾(Neomysis japonica)卵巢发育与卵子发生

结合日本新糠虾雌性生殖系统的解剖特征和组织结构特点，首次对日本新糠虾卵巢发育及卵子发生进行分期，并对各期卵巢发育时间及卵巢长与体长间相互关系进行分析。结果表明，日本新糠虾雌性生殖系统由卵巢和输卵管组成。卵巢呈“H”形，分左右两叶，两叶间有呈近三角形横桥连接，横桥内侧为生殖上皮。卵巢实质不分叶，卵细胞由横桥向两侧卵巢迁出并逐渐发育变大。卵子的发生经历5个阶段，分别为卵原细胞、卵黄合成前期卵母细胞、内源性卵黄合成期卵母细胞、外源性卵黄合成期卵母细胞和成熟期。滤泡细胞随着卵细胞的迁移而迁移，卵细胞发育后期出现滤泡细胞与卵母细胞相融合现象。卵巢发育分为5个时期，分别为未分化期（以卵原细胞为主，约为孵化后的18d）、小生长期（以内源性卵黄合成期卵细胞为主，约为孵化后的22d）、大生长期（以外源性卵黄合成期卵细胞为主，约为孵化后的25d）、成熟期（以成熟卵细胞为主，约为孵化后的28d）和退化期（为排卵后卵巢，约为孵化后的32d）。退化期卵巢中未见有结缔组织增生，而实质中存在着大量早期卵细胞，滤泡细胞呈多层分布于卵细胞周围。输卵管自卵巢末端生出，开口于第6胸肢基部内侧腹甲上，随卵巢发育，管腔渐增大。日本新糠虾卵巢长与体长间有正相关。

OVARY DEVELOPMENT AND OOGENESIS OF NEOMYSIS JAPONICA

The anatomy and histology of reproductive system of female Neomysis japonica were observed. The developmental stage and the correlation between ovary length and body length were studied. The results show that the reproductive system of female N. japonica is H-shaped and includes an oviduct. The ovary includes the left and the right parts connected by a proliferation center. The oogonias and follicle cells are originated from the germinal epithelium of the center. The volumes of the marsupium and the ovary increase with the ovary development, while that of the proliferation center decreases. No connective tissue was found in the solid portion of the ovary. The volume of oocytes in the left or right part is larger than that of oocytes in the proliferation center. Oogenesis could be divided into five stages: oogonium, previtellogenic oocytes, endogenous vitellogenic oocytes, exogenous vitellogenic oocytes and mature oocytes. The oocytes in the left and the right part of the ovary are the same type in the same stage. The oocytes in early development stage distribute mainly in proliferation center, but only one in the left or the right part. In addition, the ovary development could be also divided into five stages: inactive stage (ovaries containing oogonias, 18d), minor growth stage (endogenous vitellogenic oocytes occur, 22d), major growth stage (exogenous vitellogenic oocytes occur, 25d), mature stage (mature oocytes occur, 28d), and spawn stage (after oviposition, 32d) during which many oocytes retrogress without hyperplastic fibrous connective tissue and surrounded by many layers of follicle cells. The follicle cells and oocytes are fused in late ovarian stages. The oviduct is connected to the ovary end, and opens at the sixth pereiopod anlage. The oviduct lumen became larger with the ovary development. The ovary length and body length were positively related during the whole ovary development.