Book III chapter 4

Most of the other fish are externally oviparous, all laying an imperfect egg except the frog-fish; the reason of this exception has been previously¹ stated, and the reason also why the others lay imperfect eggs. In these also the development from the egg runs on the same lines as that of the cartilaginous and internally oviparous fishes, except that the growth is quick and from small beginnings and the outside of the egg is harder. The growth of the egg is like that of a scolex, for those animals which produce a scolex give birth to a small thing at first and this grows by itself and not through any attachment² to the parent. The reason is similar to that of the growth of yeast³, for yeast also grows great from a small beginning as the more solid part liquefies and the liquid is aerated⁴. This is effected in animals by the nature of the vital heat, in yeasts⁵ by the heat of the juice commingled⁶ with them. The eggs then grow of necessity through this cause (for they have in them superfluous⁷ yeasty matter), but also for the sake of a final cause, for it is impossible for them to attain⁸ their whole growth in the uterus because these animals have so many eggs. Therefore are they very small when set free and grow quickly, small because the uterus is narrow for the multitude of the eggs, and growing quickly that the race may not perish, as it would if much of the time required for the whole development were spent in this growth; even as it is most of those laid are destroyed before hatching. Hence the class of fish is prolific⁹, for Nature makes up for the destruction by numbers. Some fish actually burst because of the size of the eggs, as the fish called ‘belone’, for its eggs are large instead of numerous, what Nature has taken away in number being added in size.

So much for the growth of such eggs and its reason.

1 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

2 attachment   

n.附属物，附件；依恋；依附

参考例句：

• She has a great attachment to her sister.她十分依恋她的姐姐。
• She's on attachment to the Ministry of Defense.她现在隶属于国防部。

3 yeast   

n.酵母；酵母片；泡沫；v.发酵；起泡沫

参考例句：

• Yeast can be used in making beer and bread.酵母可用于酿啤酒和发面包。
• The yeast began to work.酵母开始发酵。

4 aerated   

v.使暴露于空气中，使充满气体( aerate的过去式和过去分词 )

参考例句：

• Blood is aerated in the lungs. 血液在肺中与氧结合。 来自《现代英汉综合大词典》
• The rooting medium should be moist, well aerated, and sterile. 生根的基质应当是湿润，透气良好和消过毒的。 来自辞典例句

5 yeasts   

酵母( yeast的名词复数 )； 酵母菌； 发面饼； 发酵粉

参考例句：

• The basidiospores proliperate in a manner comparable to the multiplication of yeasts. 担孢子以一种可与酵母繁殖相比拟的方式进行增殖。
• Wine yeasts can grow in sweet wines even after bottling. 装瓶以后葡萄酒酵母也能在甜葡萄酒中生长。

6 commingled   

v.混合，掺和，合并( commingle的过去式和过去分词 )

参考例句：

• Tears commingled with the blood from the cut on his face. 眼泪和他脸上伤口流的血混在一起了。 来自《简明英汉词典》
• Fact is inextricably commingled with fiction. 事实与虚构混杂难分。 来自《简明英汉词典》

7 superfluous   

adj.过多的，过剩的，多余的

参考例句：

• She fined away superfluous matter in the design. 她删去了这图案中多余的东西。
• That request seemed superfluous when I wrote it.我这样写的时候觉得这个请求似乎是多此一举。

8 attain   

vt.达到，获得，完成

参考例句：

• I used the scientific method to attain this end. 我用科学的方法来达到这一目的。
• His painstaking to attain his goal in life is praiseworthy. 他为实现人生目标所下的苦功是值得称赞的。

9 prolific   

adj.丰富的，大量的；多产的，富有创造力的

参考例句：

• She is a prolific writer of novels and short stories.她是一位多产的作家，写了很多小说和短篇故事。
• The last few pages of the document are prolific of mistakes.这个文件的最后几页错误很多。