书城外语英国学生科学读本
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第31章 游来游去的蛇

1.Snakes belong to the class①of animals which is known as reptiles.Very few snakes are found in our country.In Ireland there are none at all;and in England and Scotland there are only two kinds to be met with.

2.One of these is the common or ringed grass-snake,which is quite harmless.The other is the poisonous snake called the adder or viper.

①Class,kind;order;family.

3.A full-grown viper is rather less than two feet in length.It is of a brownish-yellow colour,with a chain of black marks running in a zig-zag①line down the back.

4.In its upper jaw it has two long hollow teeth or fangs,each of which is joined to a poison-bag in the roof of the mouth.When the viper seizes any small animal,the poison runs down through the fangs into the body of the animal and kills it.

5.The viper has also a number of small solid②teeth.Thesehave their points turned backwards,and help to hold the prey while it is being swallowed.

6.The ringed grass-snake has a double row of black spots running down its back.It has also two yellow patches or stripes on its neck.It has no poison-fangs.The ringed snake,like the viper,feeds on small animals,such as frogs and mice.

7.Snakes do not chew their food.They swallow their prey③whole;and then they go into their holes and sleep for days,or even weeks.

8.Snakes have long slender④tongues with forked⑤points.

They use their tongues rather to touch things than to taste them.

9.As snakes have no legs,how do they move ?They glide along by the help of their backbone,their ribs,and their scales.The backbone of the snake runs down the whole length of its body.It consists of many small joints or bones,to which the ribs are joined.

10.The snake‘s skin is covered with horny scales⑥.Those on①Zig-zag,crooked;out and in.

②Solid,not hollow;hard through and through.

③Their prey,the animals they catch for food.

④Slender,thin;narrow.

⑤Forked,branched;shaped like a fork.

⑥Scales,thin plates or flakes which cover the bodies of fishes and serpents.

the under side of the body are larger and stronger than the rest,and are joined to the ends of the ribs.

11.When the snake wishes to move,it stretches out the front part of its body;the scales take hold of the ground beneath,and then it moves its backbone and its ribs so as to pull forward the rest of its body;and so it creeps or glides along.

12.All kinds of snakes produce eggs,and most of them lay their eggs in some warm place.Then,after a few weeks,a little snake comes out of each egg.

SUMMARY

Snakes belong to the reptile family.In England and Scotland there are the common or ringed grass-snake,which is quite harmless,and the poisonous snake called the adder or viper.The viper has two hollow teeth or fangs,through which flows the poison it uses for killing its prey.It lives on frogs,mice,and birds.The ringed grass-snake has no poison-fangs.It also lives on small animals.Snakes swallow their food whole.They creep or glide about by the help of the horny scales with which their skin is covered.They lay their eggs in warm places.

【中文阅读】

1.蛇属于动物界里的“爬虫类”。英国的蛇非常少,爱尔兰一条蛇也没有,英格兰和苏格兰也只能见到两种蛇。①2.一种是常见的“水游蛇”(ringed grass snake),基本是没有害处的;另一种是有毒的“极北蝰”(adder,也叫viper)。②3.极北蝰长大以后,也不足两英尺长③。身体是棕黄色的,背上有“之”字形的黑色条纹。

4.极北蝰的上腭有两颗又长又尖的牙,也就是“毒牙”,毒牙是中空的,连接着上腭里面的毒囊。极北蝰抓住小动物的时候,毒液就会通过毒牙流到动物体内,把动物杀死。

5.极北蝰也有很多坚硬的小牙齿,齿尖是朝后的,极北蝰吞掉猎物的时候,这些牙可以抓住猎物,不让猎物跑掉。

6.有环纹的水游蛇,背上有两排黑点子,脖子上还有两片黑色的斑点,也叫条纹。水游蛇没有毒牙,它跟蝰蛇一样,以青蛙、老鼠一类的动物为食。

7.蛇吃东西不会嚼,而是整个儿把猎物吞下去的。吞下去之后就回到洞里,一睡就睡上几天,甚至几个星期。

8.蛇的舌头又窄又长,舌尖分岔。蛇用舌头“触摸”东西,而不是“品尝”东西。④9.蛇没有脚,怎么活动呢?蛇在地上游,靠的是脊椎骨、肋骨、鳞片的帮助。脊椎骨贯穿蛇的整个身体,是由很多块“关节”也叫“椎骨”连接起来的,肋骨就连在这些椎骨上面。

10.蛇的皮盖着一层角质鳞。蛇身子底下的鳞片,比别处的鳞片更大,更坚硬,连在肋骨的末端。

11.蛇想要活动的时候,把身体前半截往前伸,鳞片抓住身体下面的地面,然后运动脊椎骨和肋骨,把后半截身子往前拉。这样蛇就可以向前“爬”,或者“游”。⑤12.所有的蛇都会产卵,大部分的蛇把卵产在某些温暖的地方。几个星期之后,每个蛇蛋里就会钻出一条小蛇来。

译注

①生物学上,蛇属于“脊索动物门”、“爬行纲”、“有鳞目”、“蛇亚目”。蛇属于变温动物,在非常寒冷的地方不能生存。爱尔兰没有蛇,主要是因为爱尔兰在15000年以前到处都是冰,冰化了以后,爱尔兰和英格兰之间的陆地已经被水淹没了,蛇没法从英格兰爬过去了。

②这个说法过时了,其实英国还有第三种蛇:“滑蛇”,英语是smooth snake。英国的蛇种类这么少,主要是因为气候寒冷。中国的蛇有200多种,毒蛇有50多种,大部分都在南方。

③两英尺是大概61厘米。这个说法不准确,极北蝰长大以后的长度,大概是60-90厘米。

④蛇确实会用舌头舔东西,但舔并不是为了触摸,而是闻气味。在平时,蛇不停地用舌头采集空气、地面、水中的气味微粒,送到口腔中的上腭内侧,那里有一个叫“犁鼻器”的器官,有两个开口,正好让分岔的舌尖伸进去。因为舌尖分为左右两个,所以当气味从一个方向传来的时候,左右舌尖捕捉到的气味微粒数量不同,这就让蛇可以辨别气味传来的正确方向。蛇的听觉非常糟糕,这种灵敏的嗅觉,大大弥补了它听觉的不足。

⑤这是蛇类几种运动方式中的一种,名叫“直线运动”。除此之外,蛇还会“蜿蜒运动”、“伸缩运动”、“侧向移动”、跳跃等运动方式。你看,蛇虽然没有脚,运动的办法可多得很呢!但是,蛇的速度实际上是不快的,世界上爬得最快的非洲“黑曼巴”蛇,也只能在很短的时间内达到16-19公里的时速。人们感觉蛇爬得很快,一是因为蛇在瞬间确实能够爬得比较快,二是因为人们发现蛇的地方,大都是植物很多的狭窄地方,不方便人的行动,这样人会紧张,就从心理上觉得蛇爬得快了。

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