Forming a notochord like those still found in some of today's jawless fish.

形成脊索，就像今天一些无颌鱼中发现的脊索一样。

Perhaps the chordate crowd, with their notochords, segmented muscles and big bony skeletons.

或许是脊索动物，有脊索，分节肌肉和干瘪大骨架。

And the rod down its back was a notochord, an early precursor of the vertebral column seen in vertebrates.

它背上的杆是脊索，是脊椎动物脊柱的早期前身。

For one thing, the white lines found on some of those fossils go past the eyestalks where true notochord would end.

一面，其中一些化石上发现的白线越过眼柄，而真正的脊索应该眼柄处结束。

Most of the main groups of the animal kingdom—arthropods, brachiopods, coelenterates, echinoderms, molluscs and even chordates, the branch from which vertebrates went on to develop—are found in the fossil beds of the Cambrian.

人们寒武纪群落里发现了动物王国的主要动物集群，包括腕足、腔、、软体和脊索（脊椎动物进化的分支）。

The major groups of animals we see around us today -- from sponges to arthropods to chordates -- all showed up in this little window of time in the Cambrian.

我们今天我们周围看到的主要动物群——从海绵到节肢动物再到脊索动物——都出现寒武纪的这个小时间窗口。

Simple as it was, this was one of the earliest chordates -- part of the family that would give rise to the vertebrates and includes us, making us cousins over 500 million years removed.

尽管很简单， 但这是最早的脊索动物之一——属于脊椎动物家族的一部分， 包括我们内，使我们相隔 5 亿年成为远亲。

It's called a Pikaia and it's a little wormlike creature but it's thought that this is a chordate, and that is the branch of life that we're in, so it could that this is our earliest known ancestor.

它叫卡虫，确实和普通虫子差不多，不过人们认为它是一种脊索动物，也就是说，它和我们是同一类动物，所以这也许是我们最早的祖先了。