中文摘要：

本文为探索湛江近海海域裸体方格星虫的消化系统特点，以湛江近海海域裸体方格星虫为材料，对其消化道的形态和组织学进行了切片剖析。结果表明，裸体方格星虫消化系统由口、咽、食道、肠、直肠、盲肠和肛门等组成；在直肠上附有直肠盲囊，其消化道约为体长的2．5倍，肠道通过3个回折及螺旋缠绕形成肠索；消化道管壁由内向外分为黏膜层、黏膜下层和浆膜层，黏膜层有大量的皱褶，没有连续肌肉层，而黏膜下层由结缔组织组成，含有肌纤维和血管神经等；裸体方格星虫消化道有发达的纤毛，直肠盲囊连接于直肠末端，里面充满黄色液体。

英文摘要：

To explore the characteristics of Sipunculus nudus digestive system in near sea area of Zhanjiang, Sipunculus nudus in near sea area of Zhanjiang were selected as materials to observe morphology and histology of the digestive tract. The result showed that Sipunculus nudus digestive system consisted of the mouth, pharynx, esophagus, intestine, rectum, caecum and anus. The rectal blind sac attach to the rectum, the diges- tive tract was about 2. 5 times as long as the body, and intestine loop was formed by three folds and spiral winding. The wall of digestive tract was divided into mucosa, submucosa and serous membrane, from inner to outer. Furthermore, there were a lot of creases in the mucosa, without continuous muscle layer, but the submucosa was composed of connective tissue, muscle fibers and nerve and vessel etc. The digestive tract of Sipuncuhts nudus had developed cilia, rectal blind sac was connect to the terminal rectum and filled with yellow liquid.