Dilly P N
Cell Tissue Res. 1976 Jul 26;170(2):253-61. doi: 10.1007/BF00224302.
The coenecium of Rhabdopleura consists of a series of tubes, some erect and some repent. These tubes are composed of rings, one stacked within another. The rings are smooth on the inside surface and rough outside. Newly laid down rings are thin and smooth on both surfaces, fibrous material is laid down on the external surface during growth in thickness by the cephalic shield of the zooid. The erect tubes remain discrete, but the repent tubes, which are attached to the substratum can become incorporated in a mass of secreted material. The external vertical fibres cross several rings and probably serve to anchor the stack. Besides these fibrils that run for several segments, there are other shorter fibres that run along the length of each cylindrical ring, and are not continuous across the rings. These long and short fibres have features in common with those found in the graptolites.
苔藓虫的群体由一系列管子组成，有些直立，有些平卧。这些管子由环构成，一个套在另一个里面。环的内表面光滑，外表面粗糙。新形成的环两面都薄且光滑，在生长变厚过程中，虫体头部的盾板会在其外表面沉积纤维物质。直立的管子保持分离状态，但平卧在基质上的管子可能会融入一团分泌物质中。外部的垂直纤维穿过几个环，可能起到固定叠层的作用。除了这些延伸几个节段的纤维，还有其他较短的纤维沿着每个圆柱形环的长度延伸，且不连续穿过这些环。这些长短纤维与笔石中的纤维具有共同特征。
