大多数脊索动物循环具有高压的、封闭的循环系统，心脏位于腹面。

Most chordates have a high-pressure, closed circulation with a ventral heart.

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比如，凡长有脊索（包括鲨鱼，蟒蛇，鹈鹕还有你的脊柱）的生物都归属于脊索动物门。

For instance, everything with anotochord (which would be a spine for sharks, pythons, pelicans, you) belongsin the phylum Chordata.

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的注意。因为这一类动物属于最高的脊索或半脊索动物，包括鱼类，哺乳类动物和人。

Beginning. This genus is considered a chordate, and the phylum Chordata includes fish, mammals and man.

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