岩虫的性腺发育和生殖周期

根据性腺发育的组织切片观察，岩虫（Marphysa sanguinea）性腺发育可分为增生期、成熟期、排放期和休止期4个阶段。通过连续两年每月对岩虫性腺组织切片观察可以确定，在山东省乳山海区的岩虫性腺发育为1年1个周期。12月至翌年6月为增生期；7～8月为成熟期；7月下旬至8月为排放期；9～11月为休止期，其中7月下旬至8月中旬为繁殖盛期。岩虫的性腺起源于体腔腹面生殖上皮。生殖细胞发生时不出现滋养细胞。除休止期外，生殖细胞持续发生，成熟时多次排放。雄性生殖细胞形成合胞体（syncytium），精子为原始类型。雌性生殖细胞不形成合胞体，卵母细胞在发育的早期阶段，卵黄发生期问从卵巢（生殖上皮）排入体腔中，并在体腔中发育。卵细胞成熟时，有卵外膜，结构复杂。

Development of sex gonad and reproduction cycle of Marphysa sanguinea

According to the condition of the sex gonad development,the sex gonad development of Marphysa sanguinea can be divided into the following four stages: proliferating and growing stage,maturing stage,spawning stage,and resting stage.By observing the changes of sex gonad on histological sections,it is considered that the sex gonad development of Marphysa sanguinea has only one cycle in a year in Rushan area,Shandong Province.The proliferating and growing stage is from December to the next year's June,maturing stage from July to August,spawning stage from the last ten days of July to August,resting stage from September to November and the reproduction peak from the last ten days of July to the middle ten days of August.The sex gonad of Marphysa sanguinea originates from ventral germinal epithelium.No nurse cells are found during its gametogenesis.The germ cells are successively produced except at the resting stage and are realeased in several times during maturing stage.The male germ cells form syncytium.Marphysa sanguinea's spermatozoon belongs to primitive type and has flagellum and six mitochondria.The oocytes are released from the germinal epithelia into the coelom at a relatively early stage of development during vitellogenesis.The mature ootid has the outer membrane with complex structure.