Abstract: Virtual sectioning and 3D reconstruction for revealing the internal structures of the fossil embryo Markuelia are made by using the SRXTM method. Two types (left type and right type) of coiling patterns are recognized in Markuelia. The segmentation number ranges from 64 to 70. It is preliminarily proved that the circumoral spines of Markuelia develop earlier than posterior spines. The observed digestive tract is longer than previously described. Musculature forintrovert movement, or brain, is also probably preserved.

Key words: fossil embryo, Markuelia, 3D reconstruction, segmentation

摘要： 运用同步加速器X射线层析显微技术，对化石胚胎Markuelia的内部构造进行了虚拟切片及三维重建，揭示出化石胚胎Markuelia同时存在左型和右型盘绕方式，身体分节数为64～70之间，初步证明了尾刺发育早于吻刺的观点，观察到的消化道比以前所描述的要长，并推断有可能保存有司翻吻运动的肌肉组织或脑部神经结。

关键词: Markuelia, 三维重建, 分节, 化石胚胎