All these and some others with rather hard names are in that division of the Crustacea called Entomostraca, meaning shelled creatures whose shells are cut and do not cover them all round. On this principle, an oyster on the half-shell might be called an Entomostracan.
FIG. 5.
Now to catch these lively fellows, you must take a dipping tube and be patient, and when you have got one in the tube, carefully drop it on the bottom of the "live-box" (fig. 5), and put on the cover. Examine it first with the lowest power you have. By careful management of the cover you can catch it between the top and bottom without breaking the shell, and in this prison you can study it at leisure.
V.—COCHITUATE WATER.
You have read or been told that if you look at a drop of water through a microscope you will find it full of animalculæ, and showmen will sometimes exhibit water containing entomostraca hopping about, and will try to persuade you that all water looks in the same way.
ROTIFER
VULGARIS.
