Karen Anttonen, age 12, of Millersville, Pennsylvania, for her question:
Exactly what are sluts?
Actually, a slug is just a homeless snail. There are 80,000 of these close cousins, all classed as gastropods. Their class name, Gastropoda, refers to the fact that the slugs and snails use the stomach as a foot. In other words, these legless ones glide along on their tummies. The snails build shells and carry them around as homes on their backs. A few slugs build scraps of shell, hardly worth mentioning. But none of them build whole houses for themselves.
A slug has a simple little slippery body, almost exactly like a snail's. He may be a land snail, with a lung to take oxygen from the air. Or he may have fancy gills for extracting oxygen from the water. The ones we know best are land dwelling slugs who strive to hide themselves in our gardens. All the slugs and snails of the gastropod group have soft sensitive skins that need moisture. This is why they must avoid the drying light of day.
The skin of a gastropod has glands that secrete the mucus substance that makes him feel cool and slippery. Usually, this is enough to keep him moist if he stays in the shade. But when the weather turns too dry, too hot or too cold, his moist skin needs more protection. A snail can retire into his shell and seal out the drying air with a papery screen over his door. A slug tucks his slippery little body down in the soil.
As a matter of fact, he goes below to spend most of the day, at least during the hottest part of the summer. After sunset, when things cool off a little, he comes forth to glide through the vegetation. There the little gourmet dines on the tenderest leaves he can find. And, it seems, he always selects the foliage of some favorite flower or perhaps a lettuce we were raising for ourselves.
Actually a slug does not have to select the tenderest vegetation. He happens to have a remarkable tongue called a radula. It is covered with little rasps, like a saw, and if he wishes he can saw through the tough shell of a walnut.
Ordinary garden slugs come in jet black, pasty white or brown stripes that match the soil. None of them would win a beauty contest. But the sea slugs tend to be more colorful and some are downright gorge¬ous. Their gills extend in branches or feathery tufts and many have flaps of skin that look like trailing scarves.
Several beauties live in tidal pools along the coast of California. One is called the clown sea slug. His fat white body is blotched with bright red spots and bumpy red buttons. Another looks like a mini porcu¬pine. The tan colored spikes that cover his body are tipped with tiny orange and white knobs.
The most gorgeous sea slugs live in tropical seas. A large pinkish fellow with spots wears a frilly border and a tufted plume of gills. Another could pass for a bunch of violets. One of the most interesting sea slugs clings to the sargassum seaweed off the coast of Florida. His pale, yellow brown color exactly matches the seaweed and he has several trailing scarves that exactly match its trailing foliage.