“Shells are the dwellings of creatures called mollusks, the same as the spiral snail’s shell is the house of the horny little animal that eats your young flowering plants.”
“Then the snail’s house is a shell, the same as the beautiful ones you have shown us,” Jules observed.
“Yes, my child. It is in the sea that we find, in greatest number, the largest and most beautiful shells. They are called sea-shells. To these belong the helmet-shell, cassidula, and spiny mollusk. But fresh waters, that is to say streams, rivers, ponds, lakes, have them too. The smallest ditch in our country has shells of good shape but somber, earthy in color. They are called fresh-water shells.”
“I have seen some in the water resembling large, pointed, spiral snails,” said Jules. “They have a sort of cap to close the opening.”
“They are Paludinidæ.”
“I remember another ditch shell,” said Claire. “It is round, flat, and as large as a ten or even twenty-sou piece.”
Planorbinæ
“That is one of the Planorbinæ. Finally, there are shells that are always found on land and for that reason are called land-shells. Such is the spiral snail.”
“I have seen very pretty snails,” Jules remarked, “almost as pretty as the shells in this drawer. In the woods you see yellow ones with several black bands wound round them in regular order.”