国家地理 水母为何如此迷人(3)

Moon jellies and their cousins, which include lion's mane jellies and sea nettles¹, are known as true jellies. They belong to the class Scyphozoa, in the phylum Cnidaria, which also includes corals. (A phylum is such a broad taxonomic category that humans, fish, snakes, frogs, and all other animals with a backbone² belong to the same one -- the chordates -- as do salps, which are sometimes lumped with jellies.) As adults, true jellies are shaped like upside-down saucers or billowing parachutes. They propel themselves through the water by contracting the muscles of their bells, and their tentacles³ are equipped with stinging cells that shoot out tiny barbed tubes to harpoon⁴ floating prey⁵. To reel it into their mouths, they use streamer-like appendages⁶ known as oral arms. In some species the oral arms have mouths of their own.

海月水母与包括狮鬃水母与海荨麻在内的近亲，都属于真水母。它们都是被分类为钵水母纲的动物，和珊瑚一样同属刺丝胞动物门。（门是一个非常广泛的分类范畴，以至于人类、鱼、蛇、青蛙和所有其他有脊椎骨的动物都属于脊索动物，而樽海鞘有时与水母划分在一起）成熟的真水母外观看来像是倒过来的盘子或是鼓起来的降落伞。它们藉由收缩钟状体上的肌肉在水中推进，触手上的刺丝胞可以将微小带刺的管子射向漂浮的猎物。要将食物卷入口中时，它们会使用彩带状的附器（口腕）。有几种水母的口腕上就有嘴。

Jellyfish like the dreaded⁷ Portuguese⁸ man-of-war are also related to corals, but they're part of a different subgroup, the siphonophores, which practice an unusual form of collective living. What looks like a single man-of-war is technically⁹ a colony that developed from the same embryo¹⁰. Instead of simply growing larger, the embryo sprouts¹¹ new "bodies," which take on different functions. Some develop into tentacles, for example; others become reproductive organs.

令人闻风丧胆的僧帽水母（又称为葡萄牙战舰）也和珊瑚有亲缘关系，但属于另一个不同的子群：管水母。管水母有着特殊的集体生活形式。看起来只有一只的僧帽水母，其实是从同一个胚胎发展而来的群体。这个胚胎并不只是愈长愈大，而是长出新的“身体”，每个身体都扮演不同的功能，例如有些会发展成触手，有些则成为生殖器官。

1 nettles   

n.荨麻( nettle的名词复数 )

参考例句：

• I tingle where I sat in the nettles. 我坐过在荨麻上的那个部位觉得刺痛。 来自《简明英汉词典》
• This bleak place overgrown with nettles was the churchyard. 那蔓草丛生的凄凉地方是教堂公墓。 来自辞典例句

2 backbone   

n.脊骨，脊柱，骨干；刚毅，骨气

参考例句：

• The Chinese people have backbone.中国人民有骨气。
• The backbone is an articulate structure.脊椎骨是一种关节相连的结构。

3 tentacles   

n.触手( tentacle的名词复数 )；触角；触须；触毛

参考例句：

• Tentacles of fear closed around her body. 恐惧的阴影笼罩着她。
• Many molluscs have tentacles. 很多软体动物有触角。 来自《简明英汉词典》

4 harpoon   

n.鱼叉；vt.用鱼叉叉，用鱼叉捕获

参考例句：

• The harpoon drove deep into the body of the whale.渔叉深深地扎进鲸鱼体内。
• The fisherman transfixed the shark with a harpoon.渔夫用鱼叉刺住鲨鱼。

5 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

6 appendages   

n.附属物( appendage的名词复数 )；依附的人；附属器官；附属肢体（如臂、腿、尾等）

参考例句：

• The 11th segment carries a pair of segmented appendages, the cerci. 第十一节有一对分节的附肢，即尾须。 来自辞典例句
• Paired appendages, with one on each side of the body, are common in many animals. 很多动物身上有成对的附肢，一侧一个，这是很普遍的现象。 来自辞典例句

7 dreaded   

adj.令人畏惧的；害怕的v.害怕，恐惧，担心( dread的过去式和过去分词)

参考例句：

• The dreaded moment had finally arrived. 可怕的时刻终于来到了。
• He dreaded having to spend Christmas in hospital. 他害怕非得在医院过圣诞节不可。 来自《用法词典》

8 Portuguese   

n.葡萄牙人；葡萄牙语

参考例句：

• They styled their house in the Portuguese manner.他们仿照葡萄牙的风格设计自己的房子。
• Her family is Portuguese in origin.她的家族是葡萄牙血统。

9 technically   

adv.专门地，技术上地

参考例句：

• Technically it is the most advanced equipment ever.从技术上说，这是最先进的设备。
• The tomato is technically a fruit,although it is eaten as a vegetable.严格地说，西红柿是一种水果，尽管它是当作蔬菜吃的。

10 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

11 sprouts   

n.新芽，嫩枝( sprout的名词复数 )v.发芽( sprout的第三人称单数 )；抽芽；出现；（使）涌现出

参考例句：

• The wheat sprouts grew perceptibly after the rain. 下了一场雨，麦苗立刻见长。 来自《现代汉英综合大词典》
• The sprouts have pushed up the earth. 嫩芽把土顶起来了。 来自《现代汉英综合大词典》