A GOOD LOCALITY FOR FRESH-WATER MOLLUSKS • ' 'LW* '•:**00'• • The Balanced Aquarium and the Snailery one of the useful aerators, and a favourite food of certain snails. It can be checked in its growth by introducing more snails, or by cutting off the light with a screen of yellow paper. Such a method is much better than darkening the room.
Probably no single locality would furnish all the pond plants mentioned. But any natural pond should supply plenty of three or four kinds.
If possible get water from the pond which grew the plants. If this is impracticable, use ordinary well or cistern water, or take it from the city tap.
Let the plants get used to their new station before you put in the animals. Bubbles of air rising in the water show that all is well.
Mollusks of rivers and ponds are at home in the fresh water aquarium, and live at peace with many other animal forms. Snails will be found among the leaves and stems of floating and submerged plants.
The Pond Snails (Physa), one of the best kinds for the aqua rium, will mow the conferva from the sides of the tank and will breed there, undisturbed, though fishes prey upon them.
The Trumpet Snail (Planorbis), coiled flat like a watch spring, a far lustier fellow, may be found in ponds and ditches.
Lymnxa is the name of several pond snails, whose dark, handsome shells coil to the right. They are inactive, a contrast to the ambitious, left-handed Physas.
Paludina, the marsh snail, may be represented sparingly.
Clams will live quietly in the aquarium, travelling about when they feel like it, ploughing with extended foot through the gravel.
Fishes, tadpoles and the little acrobatic Water Newt (Triton) live happily with the snails and clams, if fed regularly. Stickle backs will build nests and hatch their young. Avoid fish over three inches long.
Crayfish are best kept in separate jars; they are beasts of prey and disturbers of the peace, attacking the fish and uprooting the plants. With bits of rock they build caves in which to hide.
Small bits of meat will be eaten by crayfishes and tadpoles. Insects, including "wigglers" from a neglected rain barrel (mos quito larva?) will be eaten by the fishes. They will pick up bread crumbs. Small creatures we overlook entirely furnish food for larger animals.
13 The Balanced Aquarium and the Snailery Jars containing four or five gallons of water should maintain three or four fishes, two to three inches long, with four or five newts, three or four small tadpoles, six or eight snails and two or three clams. One or two plants extending their tops up out of the water will be appreciated by the newts, which like to take a breath of fresh air occasionally. Snails, too, and tadpoles, enjoy this chance of a change.
Stocking the Marine Aquarium.—First the bottom of the tank with an inch of cleaned beach gravel. Pebbles of various sizes add to the beauty of this foundation and offer lodgment for anemones. Fill with the purest sea water obtainable.
Sea lettuce (Ulva latissima) is the most desirable plant for the marine aquarium. Collect from tide pools on the beach bits of shell and rock fragments to which are attached young plants of it. Arrange them on the foundation of sand. Broad bands of this plant may be floated on bits of cork at the surface, and anchored at the bottom for a green background against which to see the animal life to best advantage.
Solieria chordalis has brilliant, crimson, wiry branches in profuse bunches, a beautiful contrast to the cool green Ulva. It grows on rocks and shells at a few fathoms depth.
Grenella Americana, with narrow red ribbons, is a good plant, if young specimens are used.
Many beautiful seaweeds have proved to be harmful in the aquarium. Those named above are perfectly safe. Aeration is accomplished by green plants, — so the Ulva is our dependence for oxygen supply. Let the aquarium with its plants have a few days' rest before putting in the animal life.