Book IV chapter 7

In the Testacea the body consists of but few parts, the reason being that these animals live a stationary¹ life. For such animals as move much about must of necessity have more numerous parts than such as remain quiet; for their activities are many, and the more diversified² the movements the greater the number of organs required to effect them. Some species of Testacea are absolutely motionless, and others not quite but nearly so. Nature, however, has provided them with a protection in the hardness of the shell with which she has invested their body. This shell, as already has been said, may have one valve, or two valves, or be turbinate. In the latter case it may be either spiral, as in whelks, or merely globular, as in sea-urchins. When it has two valves, these may be gaping³, as in scallops and mussels, where the valves are united together on one side only, so as to open and shut on the other; or they may be united together on both sides, as in the Solens (razor-fishes). In all cases alike the Testacea have, like plants, the head downwards⁴. The reason for this is, that they take in their nourishment⁵ from below, just as do plants with their roots. Thus the under parts come in them to be above, and the upper parts to be below. The body is enclosed in a membrane⁶, and through this the animal filters fluid free from salt and absorbs its nutriment. In all there is a head; but none of the parts, excepting this recipient⁷ of food, has any distinctive⁸ name.

1 stationary   

adj.固定的，静止不动的

参考例句：

• A stationary object is easy to be aimed at.一个静止不动的物体是容易瞄准的。
• Wait until the bus is stationary before you get off.你要等公共汽车停稳了再下车。

2 diversified   

adj.多样化的，多种经营的v.使多样化，多样化( diversify的过去式和过去分词 )；进入新的商业领域

参考例句：

• The college biology department has diversified by adding new courses in biotechnology. 该学院生物系通过增加生物技术方面的新课程而变得多样化。 来自《简明英汉词典》
• Take grain as the key link, develop a diversified economy and ensure an all-round development. 以粮为纲，多种经营，全面发展。 来自《现代汉英综合大词典》

3 gaping   

adj.口的；张口的；敞口的；多洞穴的v.目瞪口呆地凝视( gape的现在分词 )；张开，张大

参考例句：

• Ahead of them was a gaping abyss. 他们前面是一个巨大的深渊。
• The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。 来自《简明英汉词典》

4 downwards   

adj./adv.向下的（地），下行的（地）

参考例句：

• He lay face downwards on his bed.他脸向下伏在床上。
• As the river flows downwards,it widens.这条河愈到下游愈宽。

5 nourishment   

n.食物，营养品；营养情况

参考例句：

• Lack of proper nourishment reduces their power to resist disease.营养不良降低了他们抵抗疾病的能力。
• He ventured that plants draw part of their nourishment from the air.他大胆提出植物从空气中吸收部分养分的观点。

6 membrane   

n.薄膜，膜皮，羊皮纸

参考例句：

• A vibrating membrane in the ear helps to convey sounds to the brain.耳膜的振动帮助声音传送到大脑。
• A plastic membrane serves as selective diffusion barrier.一层塑料薄膜起着选择性渗透屏障的作用。

7 recipient   

a.接受的,感受性强的 n.接受者,感受者,容器

参考例句：

• Please check that you have a valid email certificate for each recipient. 请检查是否对每个接收者都有有效的电子邮件证书。
• Colombia is the biggest U . S aid recipient in Latin America. 哥伦比亚是美国在拉丁美洲最大的援助对象。

8 distinctive   

adj.特别的，有特色的，与众不同的

参考例句：

• She has a very distinctive way of walking.她走路的样子与别人很不相同。
• This bird has several distinctive features.这个鸟具有几种突出的特征。