这个词是什么意思？
A phylum of acoelomate, bilaterally symmetrical flatworms, without a definite anus. It includes three classes: Cestoda, Turbellaria, and Trematoda.
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D010986 · MeSH 2026。
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