人们发现很多螃蟹背上都黏着海草，甚至贝类。这些东西能帮助螃蟹抓住猎物——小鱼。蟹壳盖上了这些东西，鱼类就注意不到螃蟹了。

　　The mother crab carries her eggs under her broad tail. When the young ones come out of these eggs, they are not at all like crabs, and they swim about in the sea. After a while they become like their father and mother in shape, only very much smaller.

　　母蟹的卵就藏在宽大的“尾巴”（其实是腹部）下面。小蟹刚从卵中孵出来的时候，一点儿也不像螃蟹，在海里到处游。过了一段时间以后，样子就变得像父母了，只是个头儿小得多。

　　But how can a crab grow when it is covered all over with a hard crust? Every year the crab throws off its old crust or shell, and a new and bigger shell soon grows in its place.

　　但是，螃蟹浑身都是硬壳，怎么长大呢？每年螃蟹都会扔掉旧甲壳，很快，身上就会长出新的甲壳。

　　There are many kinds of crabs. The little green crabs you see running about in the shallow water on the sea-beach are not the same kind as the large ones which we like to eat. There are crabs with small bodies and very long legs, called spider crabs; and there are land crabs, which spend most of their life on land.

　　螃蟹的种类很多。你看见在海滩浅水中跑来跑去的那种青色的小蟹，并不是我们爱吃的大个儿螃蟹。有一种螃蟹叫“蜘蛛蟹”，身体很小，腿却很长；还有“陆地蟹”，一生中大部分时间都是在陆地上度过的。

　　When you are paddling in the sea, do not let a crab catch hold of your toe with its "nippers;" for these nipping-claws can give a very sore pinch indeed. See how the two crabs in the picture are fighting for a fish. How they are pinching it with their "nippers"! I wonder which of them will get it in the end.

　　你在海水中走路的时候，可不要让螃蟹用“钳子”夹了脚趾头，因为螃蟹的螯足，夹人可是很痛的！看看这幅画，两只螃蟹正在争一条鱼。它们用螯足死命地抓住鱼，打得可凶了！不知最后谁能抢到这条鱼呢？