low tide, and will sadly tempt the enthusiast to consign their delicate
hues to the aquarium. All such temptations must be resisted. Green is
the only color well adapted for healthy and oxygenating growth in the
new tank. A small selection of the purple or red varieties may perhaps
be introduced and successfully cultivated at a later day, but they are
very delicate; while the olives and browns are pretty sure to die and
corrupt the water. It must be remembered, too, that the Algae are
cryptogamous, and bear no visible flowers to delight the eye or fancy.
Of all marine plants, the _Ulva latissima_, or Sea-Lettuce, is first and
best. It has broad, light-green fronds, and is hardy and a rapid grower,
and hence a good giver of oxygen. Next to this in looks and usefulness
comes the _Enteromorpha compressa_, a delicate, grass-like Alga. After
a while the _Chondrus crispus_, or common Carrageen Moss, may be chosen
and added. These ought to be enough for some months, as it is not safe
to add too many at once. Then the green weeds _Codium tomentosum_ and
_Cladophora_ may be tried; and, still later, the beautiful _Bryopsis
plumosa_. But it is much better to be content with a few Ulvae, and
others of that class, to begin with; for a half dozen of these will
support quite a variety of animal life.

After a few hardy plants are well set, and thriving for a week or two,
and the water is clear and bubbly with oxygen, it will be time to look
about for the live stock of the marine aquarium. Fishes, though most
attractive, must be put in last; for as they are of the highest
vitality, so they require the most oxygen and food, and hence should not
be trusted until everything in the tank is well a-going.

The first tenants should be the hardy varieties of the Sea-Anemones,
or _Actiniae_,--which are Polyps, of the class Radiata. The _Actinia
mesembryanthemum_ is the common smooth anemone, abounding on the coast,