This is to be supported in the usual way on a mahogany or
other stand. On the bottom, or projecting from the sides,
proportionate-sized masses of coral or other rocks should be
introduced, among which a little soil introduced would serve
to fix and nourish the plants; and these being planted, and
the case supplied with water, might, though in their proper
element, be examined without difficulty, and at all times.
Such a case might be placed in the inside of any convenient
window, provided it were not too much exposed
to direct sun; for if placed where the sun would have
much influence on the temperature of the water, the plants
would probably suffer. Indeed, the best aspect would be
the north; and in that case, by carrying a ledge of rock just
above the water surface, a situation would be provided
which would of all others suit the beautiful Bristle Pern and
the Pilmy Perns [Trichomanes and Hymenophyllum). Some
of the very small kinds of fish and the small aquatic mol-
lusks might be introduced with advantage, and they would
impart something like animation to the water.
A miniature Aquarium of this kind, planted with the Fal-
lisneria and other aquatics, and the Trichomanes and other
Perns, and stocked with miniature fish, is no ideal thing,
but has been already constructed, and proves to be of the
deepest interest to those who are truly observers of nature.
The merit of the adaptation is entirely due to Mr. Waring-
ton, of the Apothecaries’ Hail.
Genus X X I. PILULAEIA, Linnceus.
Op this genus, there is one British species, Pilularia glolu-
lifera, the Pillwort, or Pepper-grass, a creeping-stemmed
species, with filiform grass-like leaves, growing in clusters
at intervals along the thread-like stems, and bearing the
almost sessile fructification at their base. The parts of
fructification differ considerably in position from those of
the allied genus Lsoetes, in which the spore-cases are enveloped
ill the thickened bases of the leaves, those of the
Pilularia being quite free, and attached directly to the
stem, though seated at the base of a small tuft of leaves.
They also differ in structure, the fructification of Isoetes consisting
of two different kinds of bodies, namely granular and
pulverulent bodies, occupying separate spore-cases ; while in
Pilularia the two kinds are produced within each spore-case,
the larger bodies occupying the lower, and the smaller ones
the upper parts.