Both annelids possess a closed circulatory system with tubular hearts and a dorsal and ventral blood vessel. In both specimens, pin the following.

二种环节动物皆具有闭锁循环系，包括管状的心脏及背血管，腹血管。用大头针标示二标本的下列构造：。

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Objective:To introduce blood vessel variation and its treatment during the transferring of skin flap pedicled with dorsal carpal branch of ulnar artery.

目的：介绍尺动脉腕上皮支皮瓣移植术中血管变异及变异的处理方法。

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