The best time to seek echini is at low tide, and the best places are those where the shore line is composed of rough rocks, scooped out here and there into shallow pools. Take with you a large basket, a large screw-driver, if you have one, or failing that, a knife with a long, stout blade. Wear old clothes, unless you can afford to spoil new ones. When the tide is low you can wade around in the now peaceful pools, and find the echini in the sheltered crevices, clinging to the bottom, or the perpendicular sides of the rocks, but always under water.
To dislodge them, the knife-point or the edge of the screw-driver must be neatly and skilfully worked under the victim far enough to enable you, with the exertion of some force and a steady pull, to pry him loose from the rock, whereupon he becomes your lawful prey. Next comes the cleaning process. With a small knife, detach the skin of the mouth parts from the edge of the round hole underneath, in the middle of which the mouth is situated, and remove all fluid and fleshy matter from the interior of the shell. That done, wash it out thoroughly. The bony jaws, or "Aristotle's lantern," may also be drawn out through the hole and thrown away--_unless_ you happen to be collecting for someone who is studying the anatomy of echini, in which case he must speak for himself.
Having cleaned your sea-urchin, put it in clean alcohol (same strength as for fishes) and let it soak for about twenty-four hours. This will prevent the spines from gently dropping off, like leaves in autumn, when you proceed to dry the specimen. After soaking in spirits, put the specimens out in a shady place to dry. It is a curious fact that all the echini of Ceylon and Malayana lose their spines unless soaked in spirits before drying, whereas those of the Red Sea, the Mediterranean, and the West Indies can be dried without soaking, and the spines will not fall off.
SHELLS. _"Living" and "Dead" Specimens._--The first thing that the amateur needs to learn about a shell is that it may be living or dead. As a general thing, what is technically called a "dead" shell is worthless in a cabinet. A live shell is one which has been collected with a living mollusc in it, and then duly cleaned, preserving all its beautiful colors. A dead shell is one in which the occupant died a natural death, has lain and bleached in the sunshine until its colors are entirely gone, and its form also ruined by the weather. Therefore I say, leave dead shells alone, unless it be that you are making an exhaustive collection of the species in a given locality, when a dead shell which is identifiable is as good a record as a living one. Where a shell is actually devoid of color, a dead shell is as good as a living one, provided it is collected before its edges or its angles have been rounded by exposure to the sun and rain. Many a living shell has an epidermis, the same as an animal, while a dead shell has none.