As a matter of fact, Dr. Wood did write a short chapter on the Crustacea, and here it is.
The Crustacea
The Crustacea are almost all aquatic animals. They have no internal skeleton, but their body is covered with a strong crust, which serves for protection as well as for strength. Their whole framework consists of a series of rings fitted to, and working in each other; some forming limbs, and others developing into the framework supporting the different organs. From this reason, they and the remaining animals, as far as the star-fishes, who have no limbs at all, are called “articulated” animals.
Their method of growth is very curious. Other animals, as they increase in size, experience no particular inconvenience. Not so the Crustacea. Their bodies are closely enveloped in a strong, unyielding mail, which cannot grow with them. Their armor is therefore cast off every year, and a fresh coat formed to suit their increased dimensions. Not only is the armor cast off, but even the covering of the eyes, the tendons of the claws, and the lining membrane of the stomach, with its teeth.
They all also possess the curious power of reproducing a lost or injured limb. In the former case, a fresh limb supplies the place of that lost; and in the latter case, the animal itself shakes off the injured joint, and a new one soon takes its place. Lobsters, when alarmed, frequently throw off their claws.
Theme.—Choose one of the following paragraphs and expand it into a theme. Each sentence should grow into a paragraph. The proportions to be observed are suggested by the number of amplifying sentences prescribed for the different paragraphs. Write a title above the theme.
1. (a) I like winter for its outdoor sports. [Four or five sentences.] (b) I like it no less for its indoor sports. [Four or five sentences.]
2. (a) Wearing birds is foolish, for it is a remnant of savagery, like tattooing. [Two or three sentences.] (b) It is less artistic than is often supposed. [Two or three sentences.] (c) It is unwise, because it threatens the extinction of certain species of flycatchers and warblers. [Two or three sentences.] (d) It is cruel, necessitating slaughter of innocent life, and producing callousness to suffering. [Five or six sentences.]
3. (a) A contrast between faces. [Two sentences.] (b) The face of Napoleon is intellectual, firm, and cruel. [Three sentences, giving details of the face.] (c) The face of Lincoln is intellectual, firm, and kind. [Three sentences, giving details.]