Wood R L, Cavey M J
Cell Tissue Res. 1981;218(3):449-73. doi: 10.1007/BF00210107.
Ultrastructural examination of the podium of the asteroid echinoderm Stylasterias forreri reveals that cells of the coelomic epithelium and cells of the retractor muscle are, in fact, components of a single epithelium. The basal lamina of this unified epithelium adjoins the connective tissue layer of the podium. The principal epithelial cells in the coelomic lining are the flagellated adluminal cells and the myofilament-bearing retractor cells. Adluminal cells interdigitate extensively with each other and form zonular intermediate and septate junctions at their apicolateral surfaces. The adluminal cells emit processes which extend between the underlying retractor cells and terminate on the basal lamina of the epithelium. Retractor cells exhibit unregistered arrays of thick and thin myofilaments. The periphery of the retractor cell is characteristically thrown into keel-like folds which interdigitate with the processes of neighboring cells. Specialized intermediate junctions bind the retractor cells to each other and anchor the retractor cells to the basal lamina of the epithelium. The retractor cells are not surrounded by external laminae or connective tissue envelopes. It is concluded that the coelomic lining in the podium of S. forreri is a bipartite epithelium and that the retractor cells of the podium are myoepithelial in nature. There are no detectable communicating (gap) junctions between the epithelial cells of the coelomic lining.
对海星纲棘皮动物弗氏星珊瑚（Stylasterias forreri）的肉茎进行超微结构检查发现，体腔上皮细胞和牵缩肌细胞实际上是单一上皮的组成部分。这种统一上皮的基膜毗邻肉茎的结缔组织层。体腔衬里中的主要上皮细胞是具鞭毛的腔面细胞和含肌丝的牵缩细胞。腔面细胞彼此广泛交错，并在其顶端侧面形成带状中间连接和分隔连接。腔面细胞发出的突起在下方的牵缩细胞之间延伸，并终止于上皮的基膜上。牵缩细胞呈现出粗细肌丝的无序排列。牵缩细胞的周边特征性地形成龙骨状褶皱，与相邻细胞的突起相互交错。特化的中间连接将牵缩细胞彼此连接，并将牵缩细胞锚定在上皮的基膜上。牵缩细胞不被外板或结缔组织包膜包围。得出的结论是，弗氏星珊瑚肉茎中的体腔衬里是一种二分上皮，并且肉茎的牵缩细胞本质上是肌上皮细胞。在体腔衬里的上皮细胞之间没有可检测到的通讯（间隙）连接。
