A plastron is the underside of a tortoise or turtle's shell.

海龟的底部有龟甲。

They're strong enough to crack a turtle's shell.

它们很强壮，足以把龟壳砸开。

Modern turtle shells are almost as diverse as the turtles themselves.

现代龟的壳几乎和龟本身一样繁多。

I wasn't being a hothead. I wasn't mad at losing. I was just … down. I was in my turtle shell.

我并没有恼火，也没有因为输球而发火，我只是非常的沮丧。就像是乌龟缩回了自己的壳。

Make the turtle shell out of a trash can lid.

用垃圾桶盖做乌龟壳。

Now there's black spots all over this white turtle shell.

现在这只白龟壳上全是黑点。

You see, inside a turtle shell is a very particular respiratory system.

你看，龟壳里面有一个非常特殊的呼吸系统。

Although they might look similar, turtle shells are not osteoderms, and they form through a different process.

虽然它们看起来很相似，但龟壳不是骨皮，它们通过不同的过程形成。

EDAG says it based its design on a turtle shell. The company says the design provides the right amount of strength and firmness.

爱达克称是在龟壳的基础上设计的，称这款设计具备合理的力量和硬度。

And this could help explain why it had those wide ribs ... and where turtle shells came from.

这可以帮助解释为什么它有那么宽的肋骨… … 以及龟壳的来源。

It guides the formation of the upper part of the turtle's shell, called the carapace, likely by attracting the cells that will become ribs.

它主导了称为背甲的海龟之背壳的形成，可能脊椎通过吸引肋骨细胞逐渐结合在一起而形成。

And even today, if you look closely at a turtle's shell, you can still see the marks from the beating.

即使在今天， 如果你仔细观察乌龟的壳，你仍然可以看到被殴打的痕迹。

Likewise, a later pareiasaur called Anthodon had more developed bony plates that formed a layer of armor a lot like a turtle's shell.

同样，后来一种名为 Anthodon 的翼龙具有更发达的骨板，这些骨板形成了一层很像乌龟壳的盔甲。

Over time, the evolutionary purpose of the turtle's shell changed, from digging to protection, and turtles as we know them became a thing.

随着时间的推移， 海龟壳的进化目的发生了变化，从挖掘变为保护， 我们所知道的海龟变成了一种东西。

Together, these discoveries helped fill out the timeline of turtle evolution, and it became clear that the first step in the evolution of turtle shells was the formation of wider ribs.

这些发现共同帮助填写了海龟进化的时间表，很明显， 海龟壳进化的第一步是形成更宽的肋骨。

The bird was gone. I remembered that the rationalists call this consciousness mysticism. I did not think that by any name it was shameful. The season was May of this year. I withdrew into the turtle shell of my mortality.

那只鸟不见了。我记得理性主义者称这种意识为神秘主义。我不认为这是可耻的。这个季节是今年五月。我退缩到我必死的龟壳中。