The reproductive and developmental characteristics of the nereidid polychaete, Neanthes glandicincta Southern, 1921, commonly recorded in tropical estuaries in the Indo-West Pacific, were examined from Malaysia (the mangrove area of Kuala Ibai, Terengganu) and Thailand (the Lower Songkhla Lagoon) on the east coast of the Malay Peninsula. Epitokous metamorphosis of fully mature males and females and their reproductive swimming behaviour were recorded based on ten Malaysian epitokous specimens, which were collected at night during spring tides in a period of January 2018 to March 2019. Six Thailand epitokes were obtained in February and March 2006 by the laboratory rearing of immature worms. Epitokous metamorphosis is characterised by the enlargement of eyes in both sexes, division of the body into three parts and modification of parapodia with additional lobes in the mid-body of males, and replacement of atokous chaetae in the mid-body by epitokous natatory chaetae, completely in males and incompletely in females. The diameter of coelomic unfertilised eggs in females was 100–140 µm. After fertilisation, each egg formed a jelly layer, inside which embryonic development progressed. Trochophores hatched out of the jelly layer, entering a short free-swimming larval phase followed by demersal life at the early stage of 3-chaetiger nectochaeta one day after fertilisation. Then, the larvae entered benthic life as juveniles, crawling on the bottom, at the late stage of 3-chaetiger nectochaeta two days after fertilisation. The results indicate that N. glandicincta has an annual life cycle, which is usually completed within an estuary with limited larval dispersal ability.

中文翻译：

---

Epitokous变态，生殖游泳和马来半岛东海岸的河口多毛蟹（Neanthes glandicincta Southern，1921年，Annelida，Nereididae）的早期发育

从马来西亚（瓜拉伊拜，登嘉楼的红树林地区）和泰国（宋卡拉泻湖下游）检查了印度洋-西太平洋热带河口通常记录的线虫类多足动物（1921年）的繁殖和发育特征。在马来半岛的东海岸。根据十只马来西亚动物标本记录了完全成熟的雄性和雌性的动物Epitokous变态及其生殖游泳行为，这些标本是在2018年1月至2019年3月的春季潮汐之夜收集的。在六个泰国象牙虫于2006年2月和2006年3月获得通过实验室饲养未成熟的蠕虫。Epitokous变态的特征是两性都扩大了眼睛，将身体分为三个部分，并在男性中部进行额外的裂片的伪足修饰，并用Epitokous natatory chaetae代替中部的无性cha毛，完全在雄性中，在雌性中不完全。雌性未受精卵的直径为100–140 µm。受精后，每个卵形成一个果冻层，在其中进行胚胎发育。滋养体从果冻层中孵出，进入一个短暂的自由游动的幼体期，然后在受精后的一天，在三叶ne幼虫的早期生活。然后，幼虫在受精后的两天后，在三只小白鲨的晚期进入底栖生物，在底下爬行。结果表明，N。glandicincta具有一年的生命周期，