The middle embryonic germ layer lying between the ectoderm and the endoderm from which connective tissue muscle bone and the urogenital and circulatory systems develop.
中胚层中间胚芽层，位于外胚层和内胚层之间，最终发育成结缔组织、肌肉、骨骼、泌尿系统及循环系统。
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The middle embryonic germ layer, lying between the ectoderm and the endoderm, from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop.