螠虫

单环刺螠虫受精后卵子先后排放第一、二极体，经螺旋型卵裂后生成腔囊胚，囊胚经内陷形成原肠胚，胚体于受精后24h孵化，形成担轮幼虫。

After artificial fertilization , the first and second polar body was released from the egg . The blastula was formed by spiral cleavage . The gastrula , which was formed by invagination , was hatched at 24h pf ( post-fertilization ) .

中国沿海螠虫动物（螠虫动物门）名录

A Check List of Echiurans ( Echiura ) from the China Coasts

应用组织学、组织化学和电镜技术对实验室内培养的单环刺螠虫消化道和体壁的发生及分化过程进行了研究。

The ontogenesis and differentiation of digestive canal and body wall in Urechis uniconctus was also studied using histological , histochemical and TEM methods in the laboratory .

单环刺螠（Urechisunicinctus）属螠虫动物门（Echiuroidea），是我国黄渤海沿岸常见的刺螠物种。

Urechis unicinctus , classified to Echiuroidea , is a familiar species of echiuran along the coast of Yellow and Bohai in China .