glaucus-第22部分
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The smallest bits of stone are sufficient; provided the sea…weeds
have hold of them; for they have no real roots; but adhere by a
small disc; deriving no nourishment from the rock; but only from
the water。 Take care; meanwhile; that there be as little as
possible on the stone; beside the weed itself。 Especially scrape
off any small sponges; and see that no worms have made their
twining tubes of sand among the weed…stems; if they have; drag them
out; for they will surely die; and as surely spoil all by
sulphuretted hydrogen; blackness; and evil smells。
Put your weeds into your tank; and settle them at the bottom; which
last; some say; should be covered with a layer of pebbles: but let
the beginner leave it as bare as possible; for the pebbles only
tempt cross…grained annelids to crawl under them; die; and spoil
all by decaying: whereas if the bottom of the vase is bare; you
can see a sickly or dead inhabitant at once; and take him out
(which you must do) instantly。 Let your weeds stand quietly in the
vase a day or two before you put in any live animals; and even
then; do not put any in if the water does not appear perfectly
clear: but lift out the weeds; and renew the water ere you replace
them。
This is Mr。 Gosse's method。 But Mr。 Lloyd; in his 〃Handbook to the
Crystal Palace Aquarium;〃 advises that no weed should be put into
the tank。 〃It is better;〃 he says; 〃to depend only on those which
gradually and naturally appear on the rocks of the aquarium by the
action of light; and which answer every chemical purpose。〃 I
should advise anyone intending to set up an aquarium; however
small; to study what Mr。 Lloyd says on this matter in pp。 17…19;
and also in page 30; of his pamphlet; and also to go to the Crystal
Palace Aquarium; and there see for himself the many beautiful
species of sea…weeds which have appeared spontaneously in the tanks
from unsuspected spores floating in the sea…water。 On the other
hand; Mr。 Lloyd lays much stress on the necessity of a塺ating the
water; by keeping it in perpetual motion; a process not easy to be
carried out in small aquaria; at least to that perfection which has
been attained at the Crystal Palace; where the water is kept in
continual circulation by steam…power。 For a jar…aquarium; it will
be enough to drive fresh air through the water every day; by means
of a syringe。
Now for the live stock。 In the crannies of every rock you will
find sea…anemones (Actiniae); and a dozen of these only will be
enough to convert your little vase into the most brilliant of
living flower…gardens。 There they hang upon the under side of the
ledges; apparently mere rounded lumps of jelly: one is of dark
purple dotted with green; another of a rich chocolate; another of a
delicate olive; another sienna…yellow; another all but white。 Take
them from their rock; you can do it easily by slipping under them
your finger…nail; or the edge of a pewter spoon。 Take care to tear
the sucking base as little as possible (though a small rent they
will darn for themselves in a few days; easily enough; and drop
them into a basket of wet sea…weed; when you get home turn them
into a dish full of water and leave them for the night; and go to
look at them to…morrow。 What a change! The dull lumps of jelly
have taken root and flowered during the night; and your dish is
filled from side to side with a bouquet of chrysanthemums; each has
expanded into a hundred…petalled flower; crimson; pink; purple; or
orange; touch one; and it shrinks together like a sensitive plant;
displaying at the root of the petals a ring of brilliant turquoise
beads。 That is the commonest of all the Actiniae
(Mesembryanthemum); you may have him when and where you will: but
if you will search those rocks somewhat closer; you will find even
more gorgeous species than him。 See in that pool some dozen large
ones; in full bloom; and quite six inches across; some of them。 If
their cousins whom we found just now were like Chrysanthemums;
these are like quilled Dahlias。 Their arms are stouter and shorter
in proportion than those of the last species; but their colour is
equally brilliant。 One is a brilliant blood…red; another a
delicate sea…blue striped with pink; but most have the disc and the
innumerable arms striped and ringed with various shades of grey and
brown。 Shall we get them? By all means if we can。 Touch one。
Where is he now? Gone? Vanished into air; or into stone? Not
quite。 You see that knot of sand and broken shell lying on the
rock; where your Dahlia was one moment ago。 Touch it; and you will
find it leathery and elastic。 That is all which remains of the
live Dahlia。 Never mind; get your finger into the crack under him;
work him gently but firmly out; and take him home; and he will be
as happy and as gorgeous as ever to…morrow。
Let your Actiniae stand for a day or two in the dish; and then;
picking out the liveliest and handsomest; detach them once more
from their hold; drop them into your vase; right them with a bit of
stick; so that the sucking base is downwards; and leave them to
themselves thenceforth。
These two species (Mesembryanthemum and Crassicornis) are quite
beautiful enough to give a beginner amusement: but there are two
others which are not uncommon; and of such exceeding loveliness;
that it is worth while to take a little trouble to get them。 The
one is Dianthus; which I have already mentioned; the other Bellis;
the sea…daisy; of which there is an excellent description and
plates in Mr。 Gosse's 〃Rambles in Devon;〃 pp。 24 to 32。
It is common at Ilfracombe; and at Torquay; and indeed everywhere
where there are cracks and small holes in limestone or slate rock。
In these holes it fixes its base; and expands its delicate brown…
grey star…like flowers on the surface: but it must be chipped out
with hammer and chisel; at the expense of much dirt and patience;
for the moment it is touched it contracts deep into the rock; and
all that is left of the daisy flower; some two or three inches
across; is a blue knot of half the size of a marble。 But it will
expand again; after a day or two of captivity; and will repay all
the trouble which it has cost。 Troglodytes may be found; as I have
said already; in hundreds at Hastings; in similar situations to
that of Bellis; its only token; when the tide is down; being a
round dimple in the muddy sand which firs the lower cracks of
rocks。
But you will want more than these anemones; both for your own
amusement; and for the health of your tank。 Microscopic animals
will breed; and will also die; and you need for them some such
scavenger as our poor friend Squinado; to whom you were introduced
a few pages back。 Turn; then; a few stones which lie piled on each
other at extreme low…water mark; and five minutes' search will give
you the very animal you want; … a little crab; of a dingy russet
above; and on the under side like smooth porcelain。 His back is
quite flat; and so are his large angular fringed claws; which; when
he folds them up; lie in the same plane with his shell; and fit
neatly into its edges。 Compact little rogue that he is; made
especially for sidling in and out of cracks and crannies; he
carries with him such an apparatus of combs and brushes as Isidor
or Floris never dreamed of; with which he sweeps out of the sea…
water at every moment shoals of minute animalcules; and sucks them
into his tiny mouth。 Mr。 Gosse will tell you more of this marvel;
in his 〃Aquarium;〃 p。 48。
Next; your sea…weeds; if they thrive as they ought to do; will sow
their minute spores in millions around them; and these; as they
vegetate; will form a green film on the inside of the glass;
spoiling your prospect: you may rub it off for yourself; if you
will; with a rag fastened to a stick; but if you wish at once to
save yourself trouble; and to see how all emergencies in nature are
provided for; you will set three or four live shells to do it for
you; and to keep your sub…aqueous lawn close mown。
That last word is no figure of speech。 Look among the beds of sea…
weed for a few of the bright yellow or green sea…snails (Nerita);
or Conical Tops (Trochus); especially that beautiful pink one
spotted with brown (Ziziphinus); which you are sure to find about
shaded rock…ledges at dead low tide; and put them into your
aquarium。 For the present; they will only nibble the green ulvae;
but when the film of young weed begins to form; you will see it
mown off every morning as fast as it grows; in little semicircular
sweeps; just as if a fairy's scythe had been at work during the
night。
And a scythe has been at work; none other than the tongue of the
little shell…fish; a description of its extraordinary mechanism
(too long to quote here; but which is well worth reading) may be
found in Gosse's 〃Aquarium。〃 (32)
A prawn or two; and a few minute star…fish; will make your aquarium
complete; though you may add to it endlessly; as one glance at the
salt…water tanks of the Zoological Gardens; and the strange and
beautiful forms which they contain; will prove to you sufficiently。
You have two more enemies to guard against; dust; and heat。 If the
surface of the water becomes clogged with dust; the communication
between it and the life…giving oxygen of the air is cut off; and
then your animals are liable to die; for the very same reason that
fish die in a pond which is long frozen over; unless a hole be
broken in the ice to admit the air。 You must guard against this by
occasional stirring of the surface; or; as I have already said; by
syringing and by keeping on a cover。 A piece of muslin tied over
will do; but a better defence is a plate of glass; raised on wire
some half…inch above the ed