[Footnote C: Percival.]

Upon the bottom, at various depths, lies that brilliant Radiate--type of
his class--the Star-fish. These are quiet and harmless creatures, and
favorites in the aquarium, from the pretty contrast they make with
marine plants and other objects.

The perfect transparency, elegant form, and graceful navigation of the
_Medusae_, or Jelly-fishes, render them much admired in their native
haunts, and prized for the aquarium. But they are very delicate. How
beautiful and remarkable are these headless _Discophori_, as they
float, and propel themselves with involutions of their disks and gently
trailing tentacles, and the central peduncle hanging far below, like the
clapper of a transparent bell! And yet these wonders are but so much
sea-water, inclosed in so slight a tissue that it withers in the sun,
and leaves only a minute spot of dried-up gelatinous substance behind.

Finally come the Fishes, many of which are of similar genera to those
recommended for the fresh-water tank. The Black Goby is familiar,
tamable, but voracious; the Gray Mullet is very hardy, but also rather
savage; the Wrasses are some of the most showy fish,--called in some
parts of the country Cunners,--and of these, the Ancient Wrasse,
(_Labrus maculatus_,) covered with a network of vermilion meshes on a
brown and white ground, is the most elegant.

Some points of general management are so important, and some dangers so
imminent, that we cannot pass them by unnoticed. The aquarian enthusiast
is very apt to be in too great haste to see everything going on, and
commits the common error of trying too many things at once. The aquarium
must be built up slowly and tentatively, object by object: plants first,