Page:Handbook for Boys.djvu/117

96 these lay minute eggs in a mass of transparent jelly, and are to be found on lily pads and other water plants, or crawling on the bottom, while the mussels bury themselves more or less in the mud or lie on the gravelly bottom of streams. There is also a very numerous tribe of small bivalve shells, varying from

half an inch to very minute in size, which are also mud lovers and are known as Sphærium or Pisidium, having no "common" English names, since only those who hunt for them know of their existence.

On the seashore everybody knows the mussel (Mytillus: see Fig. S), the soft dam, the round dam, and the oyster, as these are sought for food; but there is a multitude of smaller bivalves which are not so well known. The sea-snails best known on the coast north of Chesapeake Bay are the whelk (Buccinum: see Fig. 3), the sand snail or Natica, which bores the round holes often found in clam shells on the beach, in

order to suck the juices of its neighbors, and the various kinds of periwinkles (rock snails or Littorina) found by the millions on the rocks between tides. These, as well as the limpets, small boat-shaped or slipper-shaped conical shells found in similar places, are vegetable feeders. Altogether, there are several hundred

kinds found on the seashore and the water near the shore, and a collection of them will not only contain many curious, pretty, and interesting things, but will have the advantage of requiring no preservative to keep them in good condition after the animal has been taken out.

The squids, cuttle-fishes, octopus, and their snail allies are also mollusks, but not so accessible to the ordinary collector, and can only be kept in spirits.

Books which may help the collector to identify the shells he may find are:

For the land and fresh-water shells: