Anderson John Maxwell
Biol Bull. 1978 Feb;154(1):1-14. doi: 10.2307/1540770.
This paper presents, with illustrations, a description of the digestive system of Oreaster reticulatus, a species for which such anatomical details have hitherto been unavailable. Special features of the digestive system include a large, highly eversible cardiac stomach with a particularly well-developed system of securing and retracting fibers; a highly specialized pyloric stomach giving rise to paired pyloric caeca, each of which is associated with an unusually elaborate Tiedemann's pouch featuring a series of secondary pouches branching off along its length; and a set of very voluminous intestinal caeca. By comparison with other asteroids for which anatomical details and feeding biology are known (especially Patiria miniata and Porania pulvillus), it is suggested that O. reticulatus is equipped for a variety of modes of feeding. The cardiac stomach is well adapted for the digestion of large pieces of food outside the body; it may also function as a flagellary-mucous particle-collector, as the similar organ of Patiria is thought to do. The specializations of the upper part of the digestive system are closely similar to corresponding organs in the known particle-feeding species Porania pulvillus, and it seems probable that Oreaster may use its Tiedemann's pouches and intestinal caeca to bring particle-laden water into the digestive system in a manner similar to that described for Porania. Such direct observations as are available on the feeding behavior of O. reticulatus tend to confirm the conclusions inferred on indirect, anatomical grounds.
本文配有插图，描述了网纹砂海星的消化系统，此前尚无该物种此类解剖学细节。消化系统的特点包括：一个大的、可高度外翻的贲门胃，其固定和回缩纤维系统特别发达；一个高度特化的幽门胃，生出成对的幽门盲囊，每个幽门盲囊都与一个异常复杂的泰德曼氏囊相连，该囊沿其长度有一系列分支的次级囊；还有一组非常大的肠盲囊。与已知解剖学细节和摄食生物学的其他海星（特别是微小帕提海星和柔毛多孔海星）相比，表明网纹砂海星具备多种摄食方式。贲门胃非常适合在体外消化大块食物；它也可能起到鞭毛黏液颗粒收集器的作用，就像人们认为微小帕提海星的类似器官那样。消化系统上部的特化结构与已知的颗粒摄食物种柔毛多孔海星的相应器官非常相似，而且砂海星似乎可能利用其泰德曼氏囊和肠盲囊，以类似于柔毛多孔海星的方式将载有颗粒的水引入消化系统。关于网纹砂海星摄食行为的现有直接观察结果倾向于证实基于间接解剖学依据得出的结论。
