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[Illustration: PLATE V.

  1. Laurencia pinnatifolia.
  2. Polysphonia parasitica.
  3. Ulva latissima.
  4. Rhodymenia lacinata.
  5. Gracilaria confervoides.
  6. Codium bursa.
  7. Iridæa edulis.
  8. Zonaria parvula.
  9. Ectocarpus tomentosus.
 10. Corallina officinalis.]

------------------------------------------------------------------------




                             OCEAN GARDENS:
                  The History of the Marine Aquarium,

                                  AND
           THE BEST METHODS NOW ADOPTED FOR ITS ESTABLISHMENT
                           AND PRESERVATION.

                                   BY

                           H. NOEL HUMPHREYS,

       AUTHOR OF “BRITISH BUTTERFLIES AND THEIR TRANSFORMATIONS;”
               “BRITISH MOTHS AND THEIR TRANSFORMATIONS;”
                         “INSECT CHANGES;” ETC.

                             [Illustration]

                                LONDON:
              SAMPSON LOW, SON, AND CO., 47 LUDGATE HILL.
                               MDCCCLVII.




------------------------------------------------------------------------




                                LONDON:
        THOMAS HARRILD, PRINTER, SALISBURY SQUARE, FLEET STREET;
                   AND SILVER STREET, FALCON SQUARE.




------------------------------------------------------------------------




                               CONTENTS.


                             [Illustration]

                              CHAPTER I.
                                                           PAGE
        INTRODUCTION                                          1

                              CHAPTER II.
        THE FLOOR OF THE OCEAN                                9

                             CHAPTER III.
        THE AQUARIUM                                         19

                              CHAPTER IV.
        THE VEGETATION OF THE MARINE AQUARIUM                39

                              CHAPTER V.
        THE ZOÖPHYTES                                        51

                              CHAPTER VI.
        THE MOLLUSCS, &c.                                    64

                             CHAPTER VII.
        THE ASCIDIANS, BARNACLES, SEA-CUCUMBERS, NAKED
          MOLLUSCS, SEA-WORMS, &c.                           86

                             CHAPTER VIII.
        THE FISH AND CRUSTACEANS OF THE AQUARIUM             95

                              CHAPTER IX.
        CONCLUSION                                          106

                             [Illustration]

------------------------------------------------------------------------




                            LIST OF PLATES.


                             [Illustration]

                                PLATE I.

                               SEA-WEEDS.

  NO.                                                             PAGE

  1. _Delesseria sanguinea_      The Crimson Delesseria             45
  2. _Punctaria latifolia_       The Broad-leaved Punctaria         45
  3. _Chordaria flagelliformis_  The Whip-like Chordaria            45
  4. _Vaucheria submarina_       The Submarine Vaucheria            45
  5. _Hildenbrandtia rubra_      The Red Hildenbrandtia             45

                               PLATE II.

                               SEA-WEEDS.

  1. _Bangia fusco-purpurea_     The Dark-purple Bangia             46
  2. _Codium tomentosum_         The Closely-haired Codium          46
  3. _Bryopsis plumosa_          The Feathery Bryopsis          41, 46
  4. _Callithamnion arbuscula_   The Tree-like Callithamnion        46
  5. _Leathesia Berkleyi_        Berkley’s Leathesia                46
  6. _Laminaria phyllitis_       The Leafy Laminaria                46

                               PLATE III.

  1. _Porphyra vulgaris_         The Common Porphyra                46
  2. _Dumantia filiformis_       The Slender Dumantia               46
  3. _Asperococcus Turneri_      Turner’s Asperococcus              47
  4. _Rytiphlæa pinastris_       The Pine-like Rytiphlæa            47
  5. _Chrysymenia rosea_         The Rose-coloured Chrysymenia      47
  6. _Peyssonetia Dubyi_         Duby’s Peyssonetia                 47
  7. _Chordaria divaricata_      The Minutely-branching
                                   Chordaria                        47
  8. _Ectocarpus siliculosus_    The Podded Ectocarpus              46
  9. _Nemaleon multifida_        The Many-cleft Nemaleon            46
  10. _Nytophyllum punctatum_    The Spotted Nytophyllum            46

                               PLATE IV.

                               SEA-WEEDS.

  1. _Chondrus crispus_          The Curly Chondrus             41, 47
  2. _Gigartina acicularis_      The Needle-shaped or Pointed
                                   Gigartina                        47
  3. _Ceramium strictum_         The Pink Ceramium                  47
  4. _Zonaria atomaria_          The Speckled Zonaria               47
  5. _Plocamium coccineum_       The Scarlet Plocamium              47

                                PLATE V.

                               SEA-WEEDS.

  1. _Laurencia pinnatifolia_    The Pinnate-leaved Laurencia   42, 48
  2. _Polysphonia parasitica_    The Parasitic Polysphonia          48
  3. _Ulva latissima_            The Broad-leaved Ulva              48
  4. _Rhodymenia lacinata_       The Lace-edged Rhodymenia      42, 48
  5. _Gracilaria confervoides_   The Sponge-like Gracilaria         49
  6. _Codium bursa_              The Purse-like Codium              49
  7. _Iridæa edulis_             The Eatable Iridea                 48
  8. _Zonaria parvula_           The Lesser Zonaria                 48
  9. _Ectocarpus tomentosus_     The Hairy Ectocarpus               49
  10. _Corallina officinalis_    The Common Corallina               49

                               PLATE VI.

                     SEA-ANEMONES, STAR-FISH, ETC.

  1. _Geniaster equestres_       The Small Scarlet Star-fish       101
  2. _Asterina gibbosa_          The Gibbous Star-fish             101
  3. _Palmipes membranaceus_     The Bird’s-foot Star              101
  4. _Cribella oculata_          The Eyed Star-fish                101
  5. _Palæmon serratus_          The Common Prawn                   98
  6. _Edwardsia vestita_         The Clothed Sea-Anemone            54

                               PLATE VII.

  1. _Actinia clavata_           The Nailed Sea-Anemone             55
  2. _Pennatula phosphorea_      The Phosphoric Sea-pen             61
  3. A Group of _Ascidians_                                         86
  4. A Shell of the Common
    Whelk, on which are two
    specimens of _Balanus_       The Acorn-shell                    88

                              PLATE VIII.

  1 & 2. _Actinia                The Carnation-like Sea-Anemone
    mesembrianthemum_              of different colours             57
  3. _Actinia gemmacea_          The Gemmed Sea-Anemone             55
  4. _Lucernaria auricula_       The Auricula-like Lucernaria       59
  5. _Virgularia mirabilis_      The Rod-like Sea-Pen               62

                               PLATE IX.

  1. _Actinia anguicoma_         The Serpent-haired Sea-Anemone     57
  2. _Alyconium digitatum_       The Many-fingered Alyconium        61
  3. _Echinus sphæra_            The Common Sea-Egg                103
  4. _Cucumis hyalinus_          The Glassy Sea-Cucumber            89

                                PLATE X.

  1. A group of _Serpula
    contortuplicata_             The Twisted Serpula                87
  2. _Actinia crassicornis_      The Thick-horned Sea-Anemone       57

                               PLATE XI.

  A Design for a Plainly-mounted Aquarium                           34

                               PLATE XII.

  A Design for an Aquarium mounted in handsome Rustic-work          34

                             [Illustration]




------------------------------------------------------------------------




                             OCEAN GARDENS;

                                  OR,

                      GLIMPSES BENEATH THE WATERS.

                                 ――◀▶――

                               CHAPTER I.

                             INTRODUCTION.


What the vast majority of our migratory flocks of summer and autumnal
idlers generally do and think at the sea-side, cannot be better
exemplified than by reference to the clever sketches which are found
occupying entire pages of our illustrated periodicals and newspapers,
during the season of marine migration. But the habits and customs of the
annual shoal of visitors to our watering-places, may be still more
intimately comprehended through the medium of the sprightly essays which
generally accompany those truly artistic delineations.

And is there really nothing better to do—no better _regime_ to go
through, than the daily repetition of the monotonous programme of
entertainment thus playfully described and ridiculed?

Surely the visitor at the sea-side is in reach of something more
pleasant and profitable than such a routine!

Do not the sublime aspects of the ocean—the sound of its deep, ceaseless
voice—the eternal on-coming of its waves, now in calm undulations, and
now in hurtling wildness against the base of those cliffs whose white
brows are wreathed with perennial flowers—suggest other matters both for
reflection and amusement? Surely the very whispering of the breeze that
has travelled so far over that vast moving surface of the fathomless
deep, and which seems muttering of its mysteries, while laden with its
sweet saline odour—“_ce parfum acre de la mer_,” as Dumas has termed
it—might lead us towards other and higher trains of thought. Surely
those voices in the wind, mingling with the strange murmur of the waves
as they break in cadenced regularity upon the shore, rouse, in the
feelings of those who hear them for the first time, or after a long
absence, strange sensations of admiration, and curiosity, and wonder.
But no; to most of the idle crowd those sights and sounds are invisible
and unheard. Their ears have not been tutored to understand the
word-music of Nature’s language, nor to read the brightly-written signs
on its mighty page.

To appreciate Nature, as well as Art, the mind requires a special
education, without which the eye and the ear perceive but little of the
miracles passing before them. To the eye of the common observer, the
farthest field in the landscape is as green as the nearest, in the scene
outspread before him; while to the practised glance of the accomplished
artist, every yard of distance lends its new tone of colour to the tints
of the herbage, till, through a thousand delicate gradations, the
brightest verdure at last mingles with the atmospheric hue, and is
eventually lost in the pervading azure. If, then, the ordinary aspects
of Nature may not be fully interpreted by the untutored eye, how should
her more hidden mysteries be felt or understood, or even guessed at?
And, in fact, they are not, or the visitor to the sea-side, looking over
that wide tremulous expanse of water that covers so many mysteries,
would feel, like the child taken for the first time within the walls of
a theatre, an intense anxiety to raise the dark-green curtain which
conceals the scene of fairy wonders he is greedily longing to behold and
enjoy. But the lounger at the sea-side does not guess at the wonders
concealed by the dark-green curtain of the ocean, and, consequently,
never dreams of wishing to peep beneath its waving folds, to gratify a
curiosity which, in fact, does not exist.

When, however, the language of Nature is learnt, and her voice is no
longer a confused murmur to the ear, but becomes a brilliant series of
eloquent words, full of deep and exquisite meaning, then the student
will _see_ as well as _hear_; but till then, in his intercourse with
Nature, he is both deaf and blind. “Speak,” said Socrates to a youth;
“say something, that I may _see_ you.” Socrates saw not a silent man;
and those who do not hear and understand Nature’s language, cannot see
her wondrous beauty.

The mill-like repetition of worldly affairs brings on a torpor of mind,
in regard to all without the narrow circle of selfish interests and
easily purchased pleasures, which it is very difficult to wake up from.
But I would warn the suffering victims of that baneful, though secret,
presence; for when the consciousness of its existence is aroused, the
first step will have been taken towards its eradication.

I would remind all those suffering from inactivity of mind, of the
wholesome dread of that kind of mental torpor entertained by the
Gymnosophists; who, as Apuleus tells us, when they met at meals,
required that each should be able to narrate the particulars of some
discovery, or original thought, or good action, or it was deemed that he
did not exhibit a sufficient reason for being allowed to consume a share
of the viands, and he was consequently excluded from the repast. Were
each of our most idle sea-side loungers to impose upon himself the
necessity of a discovery, or an original thought, before he considered
himself entitled to dine, that torpor, so deadening to the natural
capacities of his mind, would soon give way to a state of mental
activity, which, were it only from the brightness of the contrast, would
be found highly agreeable, to say nothing of its advantages, or of the
elevating and refining trains of thought to which it would necessarily
give rise.

I know of nothing more likely to stimulate the mind to healthy exertion,
and take it out of the immediate track of common interests and
pleasures, the monotony of which is so oppressive, than the study of
natural history in some of its least explored fields, especially its
extraordinary development in connection with the waters of the ocean.
And yet, how few there are who seek that charming mode of dissipating
the dreary monotony of social life, such as it is made by the routine of
fashion or habit! A popular love of natural history, even in its best
known divisions, is, in fact, of quite recent growth. Indeed, the very
existence of such a science has been, till recently, altogether ignored
by our great national seats of learning. The earnest investigators, who
have done so much to lay bare its wonders, were either openly ridiculed,
or treated with but small respect—as useless dreamers upon very small
and insignificant matters. The very names of such true labourers in the
mine of science as our glorious old naturalist Ray, or his follower
Pulteney, or the indefatigable Ellis, the first detector of the true
nature of Zoöphytes, who measured pens with the giant Linnæus, received
no academic honour; and those of their undiscouraged successors have
been rarely heard, either in our universities or among our general
public, till the vast discoveries of geology and other allied branches
of science, in our own times, have at last aroused attention to their
importance.

Any popular knowledge of that branch of natural history which especially
concerns our seas and shores, is indeed of still more recent date. The
subject, in fact, is but even now beginning to develop itself beneath
the pens of an enterprising band of marine naturalists, with such
leaders as Johnston, Harvey, John Edward Gray, the indefatigable Gosse,
and the revered shade of the lamented Forbes at their head.

A truly popular knowledge even of those more accessible regions of our
woods and fields, is but little more ancient; for, till Gilbert White
had made the story of such knowledge as attractive as romance, in his
“Natural History of Selborne,” few guessed what an arena of ever new
interests and discoveries it presented.

Through the fascinating interpretation of the good Gilbert, many now
understand the attraction of those branches of natural history which he
so curiously investigated; but few are willing to admit that it is as
easy to make the natural features of some obscure fishing-village, with
no herbage on its bare rocks, and no bush, no blade of grass, no bird to
be seen or heard, equally interesting; yet I can assure them, that by
lifting even the mere border of that green curtain of the ocean, or by
awaiting its unveilings, as the retiring tide bears back its folds, a
host of wonders will be revealed, sufficient to rouse the most torpid
mind of the most inactive idler to their earnest and deeply-inquiring
contemplation, and arouse him to their devout admiration, as among the
most exquisite miracles of that creative and sustaining Power which is
the source of their existence.

[Illustration]

------------------------------------------------------------------------




                              CHAPTER II.

                        THE FLOOR OF THE OCEAN.


The wonders of the ocean floor do not reveal themselves to vulgar eyes.
As the oracle was inaudible to sacrilegious listeners, and as none but
poetic ears heard the cadenced beating of the feet that danced to
unearthly music, near the fountain haunted by the Muses of classic
fable—so, none but the initiated can see the myriad miracles that each
receding tide reveals on the ocean floor. The initiation, however, is
not mysterious; there are no dark rites to observe—no Herculean labours
to accomplish, before entering upon the noviciate, which at once opens a
large area of unexpected pleasures, and an ample field for admiration
and investigation. A few elementary works carefully studied, or even
this present little book attentively perused, would supply the first
helps towards _seeing_, at all events, a portion of the “wonders of the
shore,” as the brilliant author of “Glaucus” has eloquently termed those
revelations of the retiring deep.

It is the _seeing_ that is everything. But let none despair of acquiring
that power. “The name of the Devonshire squire, Colonel George Montague”
(thus wrote the late Professor Edward Forbes), “might have become one of
the greatest in the whole range of British science, had his whole career
been devoted to marine physiology;” and that mainly because, from a
sincere devotion to a favourite pursuit of his leisure, he acquired the
art of _seeing_—an art sought by so few, though open to all who will
earnestly seek it.

Each department of science requires a separate and distinct kind of
sight. The astute merchant deciphers at a glance the precise state of
the most intricate accounts, in the midst of thousands of seemingly
conflicting figures; but of the thousand interesting and wonderful
things concerning the little beetle that crosses his path in his country
walk, he is incapable of seeing any single particle; while the despised
entomologist, whom he has contemptuously observed turning over the
stones at the road-side, and peering curiously beneath them, could tell
him a tale of wonder, could preach him a sermon upon that tiny type,
such as would surely wake up many latent and unsuspected powers in his
mind, that would enable him to _see_ wonders where all had previously
been blank, and teach him that there are things well worthy of
investigation beyond the region of money-making, and the attractive but
narrow circle distinguished by the fascinating characters, £ _s._ _d._

Those who cannot _see_ Nature, who cannot see more than an unclean thing
in the little creeping beetle, are like one gazing at a carved Egyptian
record, who perceives, in the hieroglyphic scarabæus, simply the
sculptured figure of a beetle, and no more—they are in a state of
“Egyptian darkness” as regards one of the highest and most enchanting
fields of human research. But to those who have acquired this rare
though easy art, and learned to _see_ Nature, even to a moderate extent
(for in that art are an infinite number of degrees and gradations), the
aspect of the ocean floor must present an appearance as beautiful and
strange, and seemingly as supernatural, as the wildest imagination could
depicture.

When poets would travel, in their inventive flights, to other floating
and revolving worlds than ours, they describe rosy skies, instead of
azure, and trees like branching crystals, with jewel-like fruits
glittering on every stem. They present us with pictures, in short, in
which all the ordinary aspects of our planet are reversed, or
metamorphosed, in the region of their invention; but in their most
fanciful pictures they do not surpass in strangeness the wonders of the
world beneath the sea.

On the land, we have, as the ordinary aspect of Nature, the green
herbaceous mantle of the earth below the eye, and the azure sky above;
while a spectator, standing beneath the water on the ocean floor, would
see these features more than reversed: he would see above him a liquid
atmosphere of green, and below, an herbage of red or of purple hue,
exhibiting strange yet exquisite forms, such as no terrestrial
vegetation displays. Roseate shrubs of jointed stone, and arborets of
filmy glass, and creatures full of active, energetic life, whose forms
are stranger still, both in structure and in appearance; mere worms,
whose colours are gorgeous as the tints of the butterfly’s wing, or the
peacock’s tail, or the humming-bird’s breast.

What scenery is formed by that translucent and miniature forest of
_Delesseria sanguinea_, how lovely in its tones of soft rich crimson;
and those fan-like shrubs, in crisply graceful tufts, the bright and
singular _Padina pavonia_; and the tree-like masses of _Callithamnion
arbuscula_, and the delicate _Ptilota plumosa_, and the purple-tinted
_Corallines_, forming those

                      “Arborets of jointed stone.”

And then the high waving fronds of the grandly graceful _Porphyra
vulgaris_, the deep carmine of the _Iridæa edulis_, the nacreous tinges
of the _Chondrus crispus_, and the blood-red of the splendid _Rhodymenia
lacinata_, with its embroidered and lace-like edges; these, with the
gorgeous tufts of the rich purple _Bangia_, and other objects which form
the elements of still life in a submarine landscape, surely cannot be
surpassed, either for magnificence of colour or variety of structure.

But to these features must be added others more extraordinary—forms that
the elder naturalists imagined to be links between the animal and
vegetable creation, but which are now known to have no affinity whatever
with plants, though they exhibit the appearance of expanded flowers of
various hues, displaying the forms of the Carnation, the Anemone, the
Mesembryanthemum, and other beautiful flowers whose names they bear.
These curiously beautiful Zoöphytes, the wonderful _Actiniæ_, exhibit
every tone of colour, from purple and scarlet, to green and white, and
might be taken in their picturesquely-placed groups for rare exotic
flowers, planted among the rosy-tinted shrubs expressly to add the last
touch of richness and effect to the scenery of an ocean flower-show.

Yet they are not flowers, but animals—sea monsters, whose seeming
delicate petals are but their thousand Briarean arms, disguised as the
petals of a flower, and expanded to seize the unconscious victim as he
passes near the beautiful form—fatal to him as the crater of a volcano;
in which he is soon engulphed by the closing tentacles of his
unsuspected enemy. And if he pass not near enough for that deadly floral
embrace, those pretty crimson tubercles that dot so gracefully the
seeming stalk, beneath the seeming flower, can shoot forth a thread,
armed, like the fisher’s line, with a barbed hook, which strikes and
secures the distant prey; and so the unwary _Annelid_ or _Infusory_ is
captured and devoured. In this capacity the creature has been compared
to Pope’s spider, who

           “Feels at each thread, and lives along the line.”

But then the living thread of the _Actinia_ (or of the _Cirriped_, which
has a similar power) is a fact, while the sensitive gossamer of the poet
is a fiction.

But notwithstanding these ogre-like attributes, the lovely _Actinia_
long deceived our naturalists as to its true nature—and of course the
poets—from whom his flower-like disc and petaloid tentacles completely
concealed his grosser nature. Then, as the tide recedes, he so meekly
closes his beautiful _oubliette_, with so much grace, and looking so
much like those shrinking flowers that close at eve, as though they
dared not to look on the black darkness of the night, that it is no
wonder poets were beguiled, and that the romantic Southey sings of the
_Actinia_ as of some lily of the deep that, on the retiring of the
ocean,

             “Sinks down within its purple stem to sleep.”

To add to the wonders of this strange landscape come the creeping
_Nudibranchs_ and _Tectibranchs_, gliding over the gracefully-waving
_Algæ_; their elegant forms decorated with their external breathing
apparatus, like the pale skeleton of some delicate flower, so fine are
its milk-white filaments, arranged nearly always in a symmetrical and
star-like form. And then there are the singular and shadowy _Medusæ_
floating past, in the form of parachutes, with low suspended cars, just
as though the science of ballooning had been carried to perfection under
the sea; and that they were made of elastic glass, instead of silk,
though richly flushed with iridescent and varying tinges, sometimes
metallic azure, and anon emerald green; hues that seem added by some
delicate process which the glass-blowers above the water have not yet
discovered. Some of these creatures are fragile as a soap-bubble, to
which their transparency and prismatic flashes of colour give them a
curious resemblance; and their ephemeral existence, dependent upon the
will of even an angry ripple of the element in which they live, is
doubtless as brief.

The deep has even its butterflies, as well as the land. The fluttering
of the fins of some small and brightly-coloured fish has been compared
to the action of the wings of moths—as also the members, likewise used
for locomotive purposes, of some of the animals of the univalve shells.
Then there are minute phosphorescent animals, which represent the
fire-flies of the south, pouring a living flood of light as they glide
along—some emitting silvery, and others golden flashes, like floating
lamps that seem hurrying to light up the darkness of the far ocean
depths.

Even the worms are gorgeous and wonderful in this subaqueous world. The
_Serpulæ_, with their radiating coronets of crimson _branchiæ_; the
_Pectinaria_, with its golden comb, glittering in burnished brightness;
and the _Nereis_, with white and crimson stripes—are all wonderful as
well as beautiful objects. But the _Halithea_, or sea-goddess, as Lamark
has named it, from the extraordinary beauty and the gorgeous colours
that radiate from the silky hairs with which it is clothed, surpasses
them all.

These, and other wonders of still greater beauty, will reward the
persevering student who learns to _see_ them; but then he _must_ learn.
Even the intellectual giant, Shakspeare, could not see clearly many of
the minuter things of Nature. In his line upon the slow-worm, for
instance, vulgarly called the blind-worm, which he describes as

                      “The eyeless, venomed worm,”

are concentrated two mistakes; in the first place, the minute eyes of
this little creature are brilliant in the extreme, and not very
difficult to discover, to the naturalist who has learnt to see nature;
and, in the second place, it has no venom, its tiny bite being perfectly
harmless. In another place he speaks of

                      “The blind-worm’s _sting_.”

But it is useless to multiply examples of the physiological errors of
great men who had not learned to _see_ Nature; or, Milton’s errors in
regard to the leaf of the Banyan-tree, and many others, might be readily
cited.

There are many glorious things to be seen in the sea, but we have to
learn to _see_ them; and those who find they cannot see with their own
eyes, must do so through the more gifted sense of others. To many—how
many, unguided by an able Cicerone—the fields round Selborne would
appear common and uninteresting enough; but guided by a Gilbert White,
whose searching eye knew even the hidden forms of plants, whose ear at
once distinguished and classified the song of birds, and even the buzz
of insects—guided by him, things assume a far different aspect; like
another Prospero, he waves his wand, and every object begins to
brighten, and a thousand new and beautiful features develop themselves
under the magic of his descriptions; crowds of marvels springing up
around, as from enchanted ground. In like manner, guided by the
fascinating science of a Johnston or a Harvey, or the persuasive
industry of a Gosse, or the eloquently glowing descriptions of a
Kingsley, students, who have not the energy or leisure to work for
themselves, will find the dark ocean glow with an unexpected light; and
the delighted explorer will long for the power to renew the impressions
of his sea-side rambles after his return to his inland home, perhaps in
the heart of a densely-populated city. Even this he may now do through
the medium of the marine Aquarium, within the narrow boundaries of which
he may, with a little care and experience, establish in healthy
existence some of the most beautiful of the animal and vegetable forms
that people the caves and depths of the ocean, and make its watery world
a region of wonders.

------------------------------------------------------------------------




                              CHAPTER III.

                             THE AQUARIUM.


The successful treatment of aquatic plants and animals, in the confined
space of a glass Aquarium, depends entirely upon the discovery that
there exists in Nature a self-adjusting balance between the supply of
oxygen created in water, with the quantity consumed by aquatic animals.
And it became equally necessary to know the means by which that supply
was continually generated. Without the knowledge of these facts, and the
principles by which they are regulated, it would have been impossible to
establish such a marine Aquarium as that we may now any day examine in
the Regent’s Park; where, in a few glass tanks of very moderate size, we
may see examples of some of the most curious forms of animal and
vegetable life peculiar to the depths of the ocean—forms so singular,
that their first exhibition created a sense of wonder little less
intense than that which must have been caused, long years ago, by the
first public display of the mountain form of the elephant to the people
of cold northern countries; and much more so than the recent
introduction of the giraffe or hippopotamus, although they have never
been seen in Europe since the days of the Romans.

Those principles, the knowledge of which was requisite to enable us thus
to view the wonders of the ocean in their living state in an Aquarium,
were not mastered at once, or by one man, or in one generation. The
nature of certain relations between animal and vegetable life, upon
which they are founded, was first advanced by Priestley, towards the
close of the last century, who proved that plants give forth the oxygen
necessary to animal life. The learned Ingenhauss, a native of Breda, but
who principally resided in England, defined this principle still more
clearly, in a work the title of which pretty fully explains the entire
nature of his discovery. It was published in French, at Leyden, in 1778,
and in London, in English, in 1779. The French edition is before me, the
title of which I translate, “Experiments upon Plants, which prove their
important influence in the purification of the atmospheric air when they
are exposed to the rays of the sun, and the contrary results which ensue
when they are placed in the shade, or during the night.” The action of
the sun’s rays in disengaging the oxygen generated in plants is thus
clearly announced, and the knowledge of this principle is one of those
which have mainly conduced, as I have said, to the successful
establishment of Aquaria.

In the course of his essay Ingenhauss states, still more directly, that
plants “immersed in water,” when exposed to the action of light, emit an
air which he announces as oxygen gas; and this idea is the key-stone of
the Aquarium.

But, although the discovery of Ingenhauss at once rendered the thing
practicable, Aquaria did not then come into fashion. The science of
natural history was not at that time sufficiently advanced; for the
specimens, even in public museums, were merely heterogeneous
collections, assembled without the slightest regard to classification,
or any other useful purpose. A stuffed cat with nine legs, stood,
perhaps, next to a bottled snake, followed by the skin of a crocodile,
to be succeeded in turn by a very moth-eaten specimen of a King Charles
spaniel, “supposed, upon good authority, to have belonged to Nell
Gwynne.” A few scores of such objects, with the addition of an ostrich
egg and a few sea-shells, without any attempt at name or description,
formed a very respectable museum in those times; and we may, therefore,
easily conceive that (in so far as experiments illustrative of natural
science were concerned) the suggestions of Ingenhauss remained tolerably
dormant.

It was not till the year 1833, that Professor Daubeny communicated, to
the British Association at Cambridge, a paper concerning some new
researches prosecuted in the same direction; and not till 1837, that Mr.
Ward became the first to apply the principle to any purpose analogous to
that of the Aquarium. In that year he made a report to the British
Association, on the hermetically closed glass cases in which he had
succeeded in growing many classes of plants, and keeping them in a
healthy state without any fresh supply of air. He stated, at the same
time, his belief that certain classes of animals would live and thrive
under similar circumstances. This was the first direct hint towards the
formation of a closed Vivarium, whether atmospheric or aquatic.

In 1842, Dr. Johnston satisfactorily proved the true vegetable nature of
_Corallines_ by observing their growth in a vessel containing sea-water;
and thus was established the first true Aquarium. With the experimental
tuft of _Coralline_ was a small frond of a green _Ulva_, and numerous
_Rissoæ_, &c., and several _Annelids_ afterwards appeared, having been,
no doubt, attached to the branches of the _Coralline_, or the fronds of
the _Ulva_. At the end of four weeks the water was still pure, the
Molluscs and other animals alive, and the Confervæ grown; the
_Coralline_ having thrown out several additional articulations. After
eight weeks, the water still remained sweet. But had any animal, of even
the lowest order, been so confined, without the accompanying presence of
vegetables giving off oxygen, all of that vital gas contained in so
small a quantity of water would have been quickly exhausted, and the
water would have become corrupt, ammoniacal, and poisonous to the life
of any living thing. But the author of this experiment had not in view
the testing of the possibility of preserving the forms of ocean life in
a healthy state in confinement; his business had been to settle an
important point connected with the classification of the _Corallines_;
and having successfully decided that question, the embryo Aquarium was
abandoned.

On the 4th of June, 1850, Mr. R. Warrington communicated to the Chemical
Society a series of observations on the adjustment of certain relations
between the animal and vegetable kingdoms, very important to our present
purpose. Two small gold-fish were placed in a glass receiver, a small
plant of _Valisneria spiralis_ being planted at the same time in some
earth, beneath a layer of sand in the same vessel. All went on well by
this arrangement, without any necessity for changing the water; the
oxygen given off by the plant proving itself sufficient for the supply
of its animal co-tenants, and the water therefore remaining clean and
pure, until some decaying leaves of the _Valisneria_ caused turbidity,
and confervoid growth began to accumulate on the sides of the vessel. To
remedy this evil, Mr. Warrington brought to bear the results of previous
observations on water in natural ponds under analogous circumstances;
and, guided by these observations and their results, he placed a few
common pond-snails in the vessel containing his gold-fish and plant of
_Valisneria_.

The new inmates, immediately upon their introduction, began to feed
greedily upon the decaying vegetable matter, and all was quickly
restored to a healthy state. They proved, indeed, of still further
advantage, for the masses of eggs which they deposited evidently
presented a kind of food natural to the fishes, which was eagerly
devoured by them, so that the snails became not only the scavengers, but
also the feeders of the little colony. And so this first of true Aquaria
prospered; the animals and plants proving of mutual value and support to
each other. The snails disposed of the decaying leaves, which would have
tainted the water and rendered it unfit for the healthy existence of the
plant, and the plant in turn gave forth, under the rays of sunlight, the
supply of oxygen necessary to both fish and snails.

In January, 1852, Mr. Warrington, commenced a series of similar
experiments with sea-water; which were, at first, not so satisfactory,
but in the end proved as entirely successful. In the course of his
experiments, he found the red and brown _Algæ_, or sea-weed, less proper
for the formation of oxygen than the green. Of the latter class he
procured specimens of _Enteromorpha_ and _Ulva latissima_, which he
chiselled from the rocks about Broadstairs, along with the pieces of
chalk or flint to which they were attached; and, when he placed them in
his own marine Aquarium, he put in along with them, to represent the
pond-snails in the fresh-water tank, some of the common sea-snail,
better known as the Periwinkle (_Littorina littorea_). But these proved,
it appears, insufficient for the destruction of the mucous and
gelatinous matter that arose from the decay of the red sea-weeds, which,
however, I have no doubt may yet be cultivated with equal success with
the green, as I shall state when describing them. Under the existing
difficulty, Mr. Warrington found it necessary to aerate the water by
other means, many processes being equally available; such as injecting
fresh-water from a syringe, or establishing a drip, of some height, from
a vessel containing a supply of entirely fresh-water. Mr. Warrington
also discovered, in the course of these experiments, the necessity that
the light should pass directly through the surface of the water to the
plants, as in natural ponds and seas—a very important step in the
successful management of Aquaria; and he therefore had a slab of slate
adjusted to the side of his tank which stood next to the light.

These successful experiments, both in fresh-water and marine Aquaria,
assign to Mr. Warrington, beyond dispute, the credit of being the
originator, or inventor, if the term may be so used, of these charming
additions to our conservatories, corridors, and even living-rooms, to
which they are certainly a much more attractive and instructive addition
than the old globe of blank water, with its pair of gold-fish swimming
round and round in ceaseless gyrations, tiresome to behold, in the vain
hope of escaping from their glaring and inconvenient prison; in which
they would inevitably have perished very shortly but for the daily
change of water, which, previous to our knowledge of air-emitting plants
and their use, was absolutely necessary.

But another experimentalist was now in the field. Mr. Gosse, whose
charming works upon Aquaria and other subjects connected with natural
science, have, perhaps, made his name more widely known than that of his
predecessor, Mr. Warrington, commenced a series of experiments on the
subject of the marine Aquarium, about the same time as the last-named
gentleman, in the beginning of January, 1852. His experiments were
crowned with such complete success that he was induced to put himself in
communication with Mr. David Mitchell, the enterprising Secretary of the
Zoological Society, the result of which was the removal of the
collection of _Annelids_ and _Zoöphytes_ which Mr. Gosse had formed, to
the gardens of the Society in the Regent’s Park; where it formed the
nucleus from which has grown the magnificent series of Aquaria in the
building constructed specially for their reception. These marine Aquaria
at once became a subject of public as well as private interest, and the
Aquarium house was so crowded daily with its curious visitors, that it
was difficult to get a glimpse of the wonders of the “ocean floor,” and
its zoöphytic denizens, which were so successfully exhibited there;
principally through the skilful aid and untiring industry of Mr. Gosse,
through whose hands above five thousand specimens passed at the time,
collected at the request of the Zoological Society.

In his interesting record of his early essays, Mr. Gosse gives us many
valuable particulars concerning his successive experiments, and the
various disappointments to which he was at first subjected; many of them
from causes now too well understood to require repetition. His principal
difficulty arose from over-crowding, although his tank did not appear,
as he states, too much filled. Another disappointment was caused by
putting in animals before the smell of the putty, with which the glass
sides were fixed, had sufficiently gone off.

Mr. Gosse’s tank was made with a slate bottom, and birch pillars, in
which were grooves to receive the glass; and its dimensions were, two
feet long by one foot six wide, the depth not being mentioned.

Taking these dimensions into consideration, it will be easy to conceive,
when the following list of specimens which Mr. Gosse introduced into his
Aquarium is examined, that his population was too dense for the extent
of his province, although the space might not have appeared too much
filled for picturesque effect. Of vegetable specimens, he introduced at
once the following:—

              1. A tuft of _Furcellaria fastigiata_.
              2. Two of _Rhodymenia palmata_.
              3. One of _Dictyota dichotoma_.
              4. A small _Fucus serratus_.
              5. One _Laminaria digitata_.
              6. Two tufts of _Padina pavonia_.
              7. Several masses of _Corallina officinalis_.
              8. _Griffithsia setacea._
              9. _Delesseria alata._
             10. _Plocamium coccineum._
             11. _Phylophora rubens._
             12. _Zostera marina._

In a few days the water, poured carefully to these specimens, became
clear as pale green crystal, the green tinge being too slight to obscure
the colour of any object seen through its medium.

From these weeds alone, before any supply of Zoöphytes or Molluscs were
intentionally added, a whole host of minute animal life swarmed forth;
some, doubtless, issuing from eggs newly hatched; others from the
shelter of the matted ramifications of some of the sea-weeds, in which
they had been taken, as in a net. Among these swarming creatures were
Annelids of the genus _Syllis_, _Rissoæ_, and other minute shell-fish,
but principally _Isopodous_ and _Entomostracous Crustacea_, many of them
being so minute as not to be perceived without the use of a powerful
lens.

Of the animals next placed in this tank, of only two feet by one foot
six inches, the following is the list given:—

                                 FISH.

    1. Fifteen, Spined Stickleback   _Gasterosteus spinachia_.
    2. Seven, Gray Mullet (young)    _Mugil capito_.
    3. One, Black Goby               _Gobious niger_.
    4. One, Corkwing                 _Crenilabrus cornubicus_.
    5. One, Five-bearded Rockling    _Motella 5-cirrata_.
    6. One, Great Pipe-fish (young)  _Syngnathus acus_.
    7. One, Worm Pipe                _Syngnathus lumbriformis_.

                        SHELLS, MOLLUSCS, ETC.

    1. Two, Ashy Top                 _Trochus cinerarius_.
    2. One, Navel Top                _Trochus umbilicatus_.
    3. Three, Common Periwinkle      _Littorina littorea_.
    4. Three, Yellow Periwinkle      _Littorina littoralis_.
    5. One, Purple                   _Purpura lapillus_.
    6. One, Scrobicularia.
    7. One, Anomia.
    8. Two, Common Cockle            _Cardium edule_.
    9. Two, Ascidia.

                            CRUSTACEA, ETC.

    1. Two, Hermit Crab              _Pagurus Bernhardus_.
    2. One,    ditto                 _Pagurus Prideauxii_.
    3. Four, Sand Shrimp             _Cragnon vulgaris_.
    4. One, Prawn                    _Palæmon serratus_.
    5. Three, Crown Worm             _Serpula triquetra_.
    6. Three, White-line Worm        _Nereis bilineata_.

                              ZOÖPHYTES.

    1. Two, Thick-horned Anemone     _Actinia crassicornis_.
    2. Three, Weymouth Anemone       _Actinia clavata_.
    3. Two, Parasitic Anemone        _Actinia parasitica_.
    4. Six, Plumose Anemone          _Actinia dianthus_.
    5. Five, Daisy Anemone           _Actinia bellis_.

There were thus above seventy specimens, animal and vegetable, already
in the tank, without counting the swarms of smaller creatures, some the
young of large species, daily increasing in size; yet, our bold
experimentalist, anxious to conquer his “Russia” at one grand invasion,
still poured in fresh specimens. These consisted of:—

                                 FISH.

    1. One, Æquorial Pipe-fish       _Syngnathus æquoreus_.

                      MOLLUSCS, CRUSTACEANS, ETC.

    1. One, Rough Doris              _Doris pilosa_.
    2. Two, Magus Top                _Trochus magus_.
    3. One, Nerit                    _Natica Alderi_.
    4. One, Squin                    _Pecten opercularis_.
    5. One, Pholas                   _Pholas parvæ_.
    6. One, Pisa                     _Pisa tetraodon_.
    7. One, Cleanser Crab            _Portunus depurator_.
    8. One, Ebalia                   _Ebalia Pennantii_.
    9. One, Hermit (small)           _Pagurus . . . . . ._
    10. Three, Lobster Prawn         _Athanas nilescens_.

                            STAR-FISH, ETC.

    1. One, Brittle Star             _Ophiocoma rosula_.
    2. One, Eyed Cribella            _Cribella oculata_.
    3. Two, Scarlet Sun-Star         _Solaster papposa_.
    4. One Bird’s-foot Star          _Palmipes membranaceus_.
    5. Three, Gibbons Starlet        _Asterina gibbosa_.
    6. One, Purple-tipped Urchin     _Echinus miliaris_.
    7. Seven, Scarlet Madrepore      _Balanophillia regia_.
    8. Three, Cloak Anemone          _Adamsia palliata_.

These additions brought the collection up to above a hundred specimens,
and no doubt the tank made a glorious show; but Mr. Gosse, though the
Napoleon of his specialty, was forced to acknowledge that there was an
“impossible.” Although his collection was superb, and his interesting
tank did not look over-crowded, yet he soon discovered that a forbidden
limit had been passed, and that the creatures of the ocean that have
yards—fathoms—of their native element to their own separate share,
cannot accommodate themselves to the allotment system, in the proportion
of a square inch to each individual.

To remedy this state of things, the evil effects of which soon became
apparent, artificial aeration was resorted to, by means of another
vessel, which kept up a continuous supply of dripping fresh water. But
even this assistance did not enable the crowded colony to exist more
than ten days. In the first place, there were many predatory species,
which destroyed their associates; these kinds must, therefore, be
excluded from an Aquarium, or kept in a separate tank. But, after all,
the impossibility of providing a sufficient supply of oxygen was
evidently the great and principal cause of failure. The Univalves and
smaller Crustacea disappeared first, a disagreeable smell giving
intimation that decay was going on, the creatures that had perished
having, many of them, died in concealment, under the stones, weeds, &c.,
at the bottom of the Aquarium. The first signs of unpleasant effluvia
rising from the tank must, therefore, be carefully attended to; and, in
such cases, the Aquarium ought to be immediately searched for the cause;
which, when discovered, should be immediately removed.

 [Illustration: PLATE XI.

 A DESIGN FOR A PLAINLY-MOUNTED AQUARIUM.]

Mr. Gosse having taken out the whole of the specimens, dead and alive,
and carefully cleansed the tank, a much smaller number was put in,
which, being well selected, and having sufficient space, throve
abundantly well; and the ingenious experimentalist was at last amply
rewarded for all his persevering exertions. This result benefited others
as well as himself, for a general taste suddenly arose for this kind of
pursuit, among all who read the various works which soon appeared on the
subject; and, to gratify the new taste, a host of dealers in Aquaria
have sprung up, who are driving a brisk and profitable trade.

The first experiments of Mr. Gosse sufficiently point out the kind of
cautions to be observed in the formation of a marine Aquarium. The
vessel itself may be either quite plain in its frame-work, as shown in
Plate XI., or made more or less ornamental, to assimilate, if necessary,
with surrounding objects or furniture. The rustic style of frame,
designed in Plate XII., has been found to accord well with the general
character of the Aquarium itself, and it produces an agreeable contrast
with the usual forms of the furniture of our ordinary sitting-rooms.

 [Illustration: PLATE XII.

 A DESIGN FOR AN AQUARIUM MOUNTED IN HANDSOME RUSTIC-WORK.]

Those made by the dealers are generally formed with slate floors and
backs, and zinc columns and mountings; the smallest and most simple,
about fifteen inches long by ten inches broad, costing from a guinea to
twenty-five shillings, and those of the proportion of two feet by one
foot six costing from two pounds ten to three pounds. A small syphon
will be useful, in order to remove a portion of the water, if required,
without disturbance; and also a syringe, in order to aerate the water
when necessary, if a second reservoir of fresh-water, in a suitable
position, should not be convenient. A miniature landing-net is also
useful for the removal of decaying matter, or occasionally the living
specimens when any change may be required.

A layer of sand and pebbles, about three inches deep, placed upon the
slate flooring, is the first step towards arranging the interior of the
tank. Upon this beginning, removing the sand and stones in places to
procure a firm basis, the rock-work may be built; which should be
picturesque and fanciful in character, as partially suggested in the two
Plates, leaving miniature archways and caves for the shelter of such
creatures as shun the light, either constantly or occasionally. Such a
disposition of the rock imparts, at the same time, many pleasing effects
to the pictorial composition. These matters are not, however, much
attended to by dealers, whose arrangements of the Aquaria they offer for
sale are generally tasteless enough. But that is perhaps all the better,
as it entails upon the amateur the necessity of providing his own taste,
which is at all times both a useful and pleasant effort of mind, and
which, moreover, leaves, after each period of exertion, a permanent
trace of an increased refinement which influences the whole character.

In the distribution of the rocks, I would always allow at least one
point to project above the water, in order to afford the opportunity to
those animals whose instincts lead them to seek occasional exposure to
the air, the means of gratifying it by that contrivance. I have thought,
indeed, of constructing a kind of double Aquarium, and perfecting a
contrivance by means of which a large portion of water should flow
gradually from one tank to the other at fixed periods, in imitation of
the ebb and flow of the tide. Many interesting phenomena would be
exhibited in this manner, such as the closing of the _Actiniæ_ as the
water receded, and their expansion as it covered them on its return.
This alternation, too, might be found highly advantageous to the health
and development of the animals whose natural habitat lies between high
and low water-mark, and whose constitution is therefore framed to
require entire or partial exposure to the air at certain intervals of
time. I also prefer, as preserving a similar set of analogies, a sloping
bottom, similar to that of the coast. For instance, if the slate back of
the Aquarium be placed next the light, which is its proper position, as
the light ought to penetrate the water entirely through its upper or
horizontal surface, then I would fill the side next the slate back
nearly to the top with pieces of rock, gradually reducing their height,
till, at the other side, they should hardly rise above the floor of sand
and pebbles, leaving, at last, a flat portion of the pebbly or sandy
bottom quite level.

When this form of rock-work is decided upon, the Aquarium should be of
rather wider proportions than usual, in order to allow of the slope
being pretty gradual. Supposing the tank to fill entirely the recess of
a spare window, which is a position in which it looks exceedingly well,
a solid slate back may be found to darken the vessel or the room too
much; in such a case, a glass back must be preferred, which can be
shaded from the direct influence of the light by a blue or green shade
of calico neatly fitted to the frame; and it must be borne in mind, as
essential, that the Aquarium must be so placed as to receive the direct
rays of light during some part of the day, being screened by a white
blind when the sun may be too powerful; as should the water become
_tepid_, it would be fatal to many of the inhabitants of the miniature
sea.

With due observance of these precautions, the amateur may hope to frame
and establish an Aquarium in a suitable form, and in a suitable position
for the reception of its inmates; an account of which, and of the manner
of their introduction, will form the subject of the ensuing chapters.

[Illustration]

------------------------------------------------------------------------




                              CHAPTER IV.

                 THE VEGETATION OF THE MARINE AQUARIUM.


As the forest must be planted before its denizens can luxuriate in its
shades, so the submarine shrubbery of the Aquarium must be perfected
before the aquatic animals can be introduced. For it has been shown, in
tracing the history of the experiments which resulted in the
establishment of the principles that regulate the formation of Aquaria,
that it is by plants only that a supply of oxygen can be kept up,
sufficient for the health and existence of all forms of animal life
beneath the water.[1] It is necessary, also, that the rays of sunlight
should fall upon the foliage directly through the surface of the water;
and when an Aquarium, with its plants, is placed in a position to
receive the light in this manner, their fronds may be observed giving
forth the gas in small silvery bubbles and corruscations, which have a
brilliant and gem-like appearance.


[Footnote 1: Analogous principles are at work in our fields and forests,
but we have now only to do with the submarine production of oxygen.]


Some marine plants appear to succeed much better than others, but I
believe that happens only from their treatment being imperfectly
understood; and I believe, not only that all the exquisitely beautiful
marine _Algæ_ of our own shores may be successfully grown, but also that
the more splendid varieties of the tropical seas may be made to thrive
in properly-heated Aquaria, and thus form one of the most attractive
features of our hot-houses—one that has not yet been dreamed of.

In ordinary Aquaria, such as I am now treating of, I shall name first
those species of sea-weed recommended by Mr. Gosse and others as most
easily cultivated, but I shall also point out many other species, which
I feel convinced may be successfully grown under proper management; and
they certainly deserve every effort that can be made to establish them
in Aquaria, as they are among the most beautiful of their tribe.

If not purchased of dealers, the plants must be very carefully collected
by the amateur himself, taking care to detach a portion of the substance
to which they are growing, and packing them in damp refuse sea-weed,
keeping them out of their native element as short a time as possible.

The plants in most flourishing condition in the marine tanks of the
Zoological Gardens, were at first those of the _Chlorospermatous_ order,
but others have since succeeded nearly as well. Plants of _Ulva_ and
_Conferva_ have done very well, but the most successful growth has been
that of a plant of the genus _Bryopsis_, which, entirely enveloping a
large stone in its mossy and almost feather-like foliage, produces a
very beautiful appearance. Those unlearned in scientific names will be
glad, perhaps, to learn that these beautiful _Algæ_ derive their title
from two Greek words, Bryon (βρυον), a moss, and opsis (οψιϛ), a
resemblance, from their likeness to some of the most delicate and
feather-like mosses of our woods. The delineation of _Bryopsis plumosa_
in Plate II., on the extreme left near the lower part of the Plate, will
convey some idea of these elegant sea-weeds.

_Chondrus crispus_ is a beautiful plant, and well suited to the
Aquarium. It will often be found under ledges of rock, completely
concealed by a pendant veil of _Fucus_, commonly known as the
olive-weed; and, on lifting the tangled mass of its rank growth, many
beautiful and unexpected plants are frequently found, but none strike
the explorer more than the _Chondrus_. Its nacreous tints, like those of
a pearl shell, varying wonderfully according to situation, being very
remarkable. It is the Carrageen Moss of the herb market. This plant
forms the principal object in the lower part of Plate IV., to the right.

_Laurencia pinnatifolia_ is a pretty branching plant, also varying in
hue according to the aspect in which it grows. In the shade it is
purple, but when receiving the full influence of the sun’s rays, it
assumes a light-yellow tone; just as the _Lycopodium_, known as
Fortune’s Moss, is purple when grown in the darkest part of a room, but
becomes of an ordinary green tone when placed for some time near the
light. The _Laurencia_ is shown at the upper part of Plate V., coloured
pale-violet.

The splendid plant _Rhodymenia palmata_, with its finely-coloured,
semi-transparent fronds, is also recommended. It is the Dulse, or
Dellis, eaten by the inhabitants of our northern coasts as a delicacy.
Another species of _R. lacinata_ is represented to the left of Plate V.,
the transparent light-crimson fronds of which are excessively beautiful.
Mr. Gosse tells us that the _Rhodymenia palmata_ is not suited to an
Aquarium, because it appears to require the motion of the sea, and soon
begins to decay in still water. If that be the case, let us provide a
remedy, for the plant is one of the most beautiful among all its lovely
congeners. When a plant of the gigantic lily of the Amazon river was
first introduced, it refused to flower in the tank provided for its
northern home, at the Duke of Devonshire’s residence at Chatsworth. But
Sir Joseph Paxton, who then directed the floricultural operations of
that magnificent abode, was not discouraged; and, seeking to impart to
the still water of the tank something of the motion of a deep and
majestic river, he contrived that a small but continuous stream should
enter at one end of the tank, and, as it entered, turn a small
paddle-wheel, the action of which imparted a gentle, undulating motion
to the water of the whole tank. The device was triumphant, and the
glorious _Victoria regia_ formed and expanded its giant flowers in the
house which its curator had constructed for it, the plan of which
eventually suggested the creation of the “Crystal Palace.” Let us not
despair, therefore, of cultivating successfully the beautiful
_Rhodymenia palmata_ in our Aquaria. The construction of a suitable
apparatus for imparting motion to the too still waters, will form a
pleasant _passetemps_ for some of our fair admirers of the pursuits of
the Aquarium; and their success would be a signal triumph. But at
present the beautiful red weeds, in general, are difficult of
cultivation, and when they begin to exhibit spots of orange—a vegetable
plague-spot not to be mistaken—it is a symptom of decay which should at
once cause their removal from the Aquarium, before their decomposition
leads to further mischief.

The common Coralline, _Corallina officinalis_, of which a small spray is
represented in the extreme lower part of Plate V., near the centre, is
the “arboret of jointed stone” alluded to by the poet, and is well
suited to Aquaria, thriving with little trouble. The smaller and
slenderer kind is also suitable; but care must be taken, in collecting,
not to choose the detached white fragments, which are washed up with
every tide, for they are only the skeletons of the plant. It is the
rosy-tinted specimens, verging to violet and purple, and still attached
to pieces of rock, that are alone fit to remove to the Aquarium.

 [Illustration: PLATE I.

 1. Delesseria sanguinea.
 2. Punctaria latifolia.
 3. Chordaria flagelliformis.
 4. Vaucheria submarina.
 5. Hildenbrandtia rubra.]

The _Cladophoræ_ are also stated to be very suitable, _C. rupestris_
being a very useful plant for the purpose. It is of a bluish-green, that
harmonizes well with the tone of the sea-water, and fills up little
chasms in the artificial rocks with very good effect, especially in
contrast with the reddish-purple tufts of _Polysiphonia arceolata_,
which do well in an Aquarium, and are a great aid to the foliage of the
little marine landscape. The elegant, fan-formed, and brightly-radiated
_Padina pavonia_ is likewise mentioned, and should at all events be
tried, as the tufts of that graceful marine plant form very singular as
well as beautiful objects in the tank.[2]


[Footnote 2: A list of the plants with which Mr. Gosse furnished his
first Aquarium is given in Chapter III.]


I would also recommend the trial of all the plants delineated in the
five Plates devoted to the sea-weeds in this little book.

In Plate I., the first, occupying the upper part, with leaf-like fronds
of transparent crimson, is the beautiful and not uncommon sea-weed,
_Delesseria sanguinea_. The delicate pale plant below, to the right, is
_Punctaria latifolia_, thin as tissue-paper, and speckled over its
pale-buff surface with bright but minute grains of black. To the left is
a branch of _Chordaria flagelliformis_, the rich olive of which
contrasts well with the red kinds of _Algæ_. In the front, growing on a
detached pebble, is the Lichen-like _Hildenbrandtia rubra_, the rich
carmine of which might be made to form an exquisite touch of colour, if
tastefully placed in the Aquarium; and to the extreme right is a small
tuft of _Vaucheria submarina_.

In Plate II., the principal object, near the top of the Plate, is a bush
of _Callithamnion arbuscula_, which receives its name from the tree-like
aspect which it assumes more distinctly than any other of the marine
_Algæ_. Behind it, to the right, are the tall and graceful forms, with
their crimped edges, of the slender _Laminaria phyllitis_. And below,
still to the right, is a branch of _Codium tomentosum_, distinguished by
its light, vivid green, and the edging of delicate ciliæ, which have the
appearance of a border of paler green, to every branchlet. Still to the
right, in the extreme foreground, is a broken piece of rock on which
plants of the curious _Leathesia Berkleyi_ have grown, like convex
kernels of bronze. To the left are the red-violet tufts of the _Bangia
fusco-purpurea_, and behind them, a branch of _Bryopsis plumosa_.

 [Illustration: PLATE II.

 1. Bangia fusco-purpurea.
 2. Codium tomentosum.
 3. Bryopsis plumosa.
 4. Callithamnion arbuscula.
 5. Leathesia Berkleyi.
 6. Laminaria phyllitis.]

In Plate III. the bright-green feathery plant in the extreme background
is _Ectocarpus siliculosus_; and behind it, the violet, antler-like
fronds of _Nemaleon multifida_. The large, gracefully-bending frond of
rich purple, with narrower and younger fronds springing from the same
root, is _Porphyra vulgaris_, one of the commonest, but most splendid of
our marine _Algæ_, with which, in combination with other plants of
suitable contrast, the vegetation of the Aquarium may be rendered truly
splendid, if it once be successfully cultivated; of which I have no
doubt, when its natural wants are sufficiently studied and ingeniously
supplied. The splendidly-marked plant to the right, with its black
maculations and richly-frilled edge, is _Nitophyllum punctatum_, one of
our most splendid species; and the curious pale-buff, tubular plant in
front of it, is _Asperococcus Turneri_. Near the foot of the
_Nitophyllum_ is a little tuft of the delicate _Dumontia filiformis_;
and, to the extreme left, a branch of the brown-fronded _Rytiphæa
pinastris_, which receives its specific name from the somewhat Pine-like
growth it frequently assumes. Immediately beneath it, on the extreme
right, is a little cluster of _Chordaria divaricata_; and below, in the
left foreground, are a few pink fronds of the curious Alga, _Chrysemenia
rosea_; while, in the foreground, to the right, on a detached pebble, is
a small mass of the pale-crimson _Peyssonetia Dubyi_.

In Plate IV. the principal object is a fasciculus of _Taonia atomaria_,
rising behind the point of rock at the top of the Plate, behind which
are two long fronds of the spotted _Asperococcus_; to the left is the
horn-like _Gigartina acicularis_; and in the front, to the left, the
crimson tufts of a pretty weed (_Ceramium strictum_), which our artist
has made too like the _Bangia fusco-purpurea_.

In Plate V. the violet-toned _Laurencia pinnatifolia_ is grouped behind
the solid, deep-crimson fronds of _Iridæa edulis_, which are often
perfectly Pear-shaped, like pieces of crimson leather neatly cut in that
form; but the action of tides in rough weather often tears the edges,
and wears holes through the texture of the plant, as shown in the
principal frond. To the left is the bright-crimson _Rhodymenia
lacinata_—one of our most exquisitely beautiful marine _Algæ_. The
fronds are as thin as the finest conceivable tissue, and beautifully
transparent, which is shown wherever the lacinations of the edge overlap
each other, in which places the double thickness of the texture doubles,
at the same time, the intensity of the colour, as indicated in the
representation. On the same level, to the right, is a small group of the
delicate green _Ulva latissima_—a plant which has proved useful beyond
all others in Aquaria, as throwing off, under the action of the light, a
much greater profusion of silvery globules of oxygen than any other
species yet known. At the same level still, on the extreme right, is a
sprig of the delicately-branched parasite, _Polysphonia parasitica_,
growing on a small mass of pale sulphur-coloured _Melobesia
lichenoides_, the Lichen-like Melobesia. To the extreme left, under the
beautiful _Rhodymenia_, is a small branch of the bright, olive-tinted
_Ectocarpus tomentosus_, looking much like a spray of wild Broom, and
immediately below it, a few purple branchlets of _Gracilaria
confervoides_; while in the left foreground lies a pebble, partly
covered by a small plant of _Zonaria parvula_, from beneath which
straggles a little branch of the common but pretty Coralline, the
_Corallina officinalis_; and, to the right, a globe of the curious
_Codium bursa_, of the French coast, which might easily be added to our
native species in the Aquarium.

 [Illustration: PLATE III.

  1. Porphyra vulgaris.
  2. Dumontia filiformis.
  3. Asperococcus Turneri.
  4. Rytiphlæa pinastris.
  5. Chrysymenia rosea.
  6. Peyssonetia Dubyi.
  7. Chordaria divaricata.
  8. Ectocarpus siliculosus.
  9. Nemaleon multifida.
 10. Nitophyllum punctatum.]

Such are a few of our beautiful coast _Algæ_, all of which I would
advise the admirers of the beauties of the marine Aquarium to try; and
if some refuse, in the present state of our knowledge of their habits
and requirements, to make themselves happy in their pretty “crystal
palace,” choosing rather to consider it a “prison of glass,” still a
good number of them, I am persuaded, may be coaxed into displaying their
beauties very genially within its transparent walls, which admit the
bright sun rays as freely as the pale-green liquid glass which forms
their native element.

The best time for making collections at the sea-side is a day or two
after the full moon, when the tide recedes to its greatest extent, and
parts of the shore become exposed, where some of the finest species
grow, which cannot be conveniently approached at any other time. It must
be borne in mind, also, that few of the floating pieces will grow,
however fresh and seemingly washed off with their root. Certain success
is only to be secured by chiselling off a portion of the substance on
which the weed is growing—thus transplanting it with its own soil, as it
were, about its roots, into the ocean garden of the Aquarium.

[Illustration]

 [Illustration: PLATE IV.

 1. Chondrus crispus.
 2. Gigartina acicularis.
 3. Ceramium strictum.
 4. Taonia atomaria.
 5. Plocamium coccineum.]

------------------------------------------------------------------------




                               CHAPTER V.

                             THE ZOÖPHYTES.


The Aquarium having been furnished with its vegetation, and rendered as
picturesque as possible by the well-arranged juxtaposition of
felicitously-contrasting forms and colours, the water must be allowed to
settle for some days, until it is as clear as pale-green crystal, before
the animals are introduced to their new home. When the Alpine scenery of
the submarine landscape appears perfectly settled, and all its colours
and forms are seen with beautiful distinctness through the clarified
waters, then the still life is ready to be associated with the more
active organizations of animated creatures. Before speaking of Molluscs,
or Crustacea, or of Fish, suitable to the Aquarium, let us first devote
all our attention to our _Zoöphytes_, those singular creatures whose
strange instincts and anomalous forms have been mainly instrumental in
attracting the attention of many classes of the public to that curious
interest in Aquaria, which is fast spreading into a mania, threatening
to absorb all others in its vortex, like _Infusoriæ_ drawn within the
fatal tentacles of the _Actinia_.

First, of the _Actiniæ_, or Sea-Anemonies. These flower-formed animals
were once thought to form a curious and astonishing link between the
animal and vegetable world; and many curious speculations, based upon
that idea, were put forth, among which the links between man and the
inferior animals, and between quadrupeds and fishes, were asserted in
further illustration of the theory. But the deceptiveness of superficial
knowledge, based upon imperfect observations, was never more strikingly
exemplified than in the present instance. It was thought that, because
these creatures were found attached to rocks, they necessarily drew
their nourishment principally through the medium of roots, as all true
plants do; more accurate observation, however, has shown that they are
not _permanently_ fixed to the rocks, and that they have the power of
moving from one place to another, and attaching themselves anew,
whenever a sufficiently disturbing cause renders such removal desirable.
Again, oysters and mussels remain fixed to rocks without being
considered allied to plants on that account; and even some fish have the
power of attaching themselves to such and other substances by means of
curiously-formed ventral fins, peculiarly fitted for the purpose. The
pretty little two-spotted sucker, _Lepidogaster bimaculatus_, possesses
this faculty.

But the flower-like form into which the arms, or food-seizers, of the
_Actiniæ_ are spread, radiating from a centre like the petals of a
flower, was the main reason for supposing a close analogy between these
strange creatures and plants—a fancy now utterly abandoned, as it is
quite evident that they are furnished with a mouth and stomach, like all
true animals, and with a set of arms called tentacles for seizing their
prey; and, perhaps, at the same time, through the medium of delicate
ciliæ with which the tentacles are connected, with a breathing
apparatus, through which a current of water is taken in, and discharged
after its oxygen has been abstracted.

The discovery of the true nature of these singular creatures has not,
however, changed their flower-like appearance, which to a superficial
observer is as deceptive as ever; and few (not professed naturalists),
observing these singular _Zoöphytes_ for the first time, would hesitate
to pronounce them a kind of sea-plant.

Let us turn, for example, to Plate VIII., and note the appearance of the
two varieties of _Actinia dianthus_—the carnation-like _Actinia_, as its
name imports—and we shall easily excuse our early naturalists their
pretty but erroneous fancies concerning them. This species is more
subject than many others to vary in colour, even like the flower after
which it is named, being found of every tone between snow-white, orange,
pale scarlet, and blood red—while some specimens take duskier tints,
from a dull brown to a kind of orange green. But we will describe our
illustrations of this genus in regular succession, noting what is most
peculiar in the subjects of each Plate.

Plate VI. contains a representation of one of the last-discovered
species of _Actiniæ_—one which displays a habit that distinguishes it
from all its congeners hitherto described by naturalists, and which has
entitled it to be classed as a separate genus, and named _Edwardsia
vestita_. The generic name is from that of a well-known naturalist, and
the specific name, _vestita_, from its habit of forming for itself a
shell, or clothing, into which it has the faculty of retiring at
pleasure; or, if an inhabitant of the shallow water, when the tide
recedes, and leaves it inconveniently exposed to the air. This species,
unless it have the power of quitting its shell, like some Molluscs, is
of necessity permanently fixed and confined to the position in which the
egg from which it was hatched was placed by the instinct of the parent,
or the caprice of the waves. The other objects in Plate VI. will be
described in another place.

 [Illustration: PLATE VII.

 1. Actinia clavata.
 3. Pennatula phosphorea.
 4. A Shell of the Common Whelk, on which are two specimens of Balanus.
 5. A group of Ascidians.]

In Plate VII. we have two remarkable species; the one with drooping
tentacles of dull brick-red, being a very curious variety. The species
below is _Actinia clavata_, one of the most delicately-beautiful
species, which, from its brilliant whiteness, at once attracts the
attention.

In Plate VIII. are two varieties, previously described, of _Actinia
dianthus_, the plumose or feather-like Anemone. In front, below them, is
the representation of one of the most splendid of all the species,
having received the specific name _Gemmacea_, from the gem-like
appearance produced by the touches of colour—blue, buff, and brown—about
the orifice of the mouth or stomach, and about its sharply-pointed
tentacles. The stem or body is also variegated with rows of brightly
tinted tubercles, and its whole surface is clouded with pale iridescent,
or rather nacreous, tones of pink and azure, varied with occasional
flashes of orange. All the species are furnished with tubercles of a
similar description about the stem or body, but in many they are not so
conspicuous, and in others almost imperceptible; yet they no doubt exist
in all, as they are not merely ornamental, but essential organs,
peculiar to this class of creatures; being reservoirs from which they
can shoot forth a thread, furnished with a barbed and poisoned dart, by
means of which they are able to attain an enemy, or victim, far beyond
the reach of their tentacles. Mr. Gosse very graphically describes the
death of a small fish struck by one of these thread-borne poisoned
arrows, at some distance from the offended _Actinia_, who launched his
dart, as it seemed, for no greater provocation than a slight disturbance
of the water rather nearer to his retreat than was agreeable.

 [Illustration: PLATE VIII.

 1. Actinia gemmacea.
 3. & 4. Actinia mesembrianthemum.
 5. Lucernaria auricula.
 6. Virgularia mirabilis.]

The _Actinia gemmacea_, it would appear, is a more voracious creature
than most of his congeners, for Dr. Johnston, in his splendid work on
the British Zoöphytes, describes one of this species that had managed to
swallow a shell of _Pecten maximus_ as large as a common saucer, its own
natural diameter not exceeding two inches. It managed, however, to
distend its elastic form sufficiently to receive the enormous prey; but
the shell divided the stomach into two completely separate departments,
the lower one being thus perfectly shut off from its usual supplies. To
meet this difficulty, the organic economy of the creature adapted itself
in a most extraordinary manner; a new mouth was opened below the
division, furnished with two rows of new tentacles, and thus the lower
portion regained a means of taking in nourishment, the whole creature
forming a singular double monster, that, not contented with its one
giant mouth, surrounded with its hundred arms to supply its voracious
appetite, had actually succeeded in supplying itself with a second,
equally furnished with its formidable feeding apparatus.

In Plate IX. a very beautifully distinct form of this singular race of
animals is very carefully delineated—_Actinia anguicoma_—which seems to
be shaking loose a mass of serpent-like hair, like another Medusa; from
which appearance, its specific name _anguicoma_, signifying
snake-haired, has doubtless been given.

The tentacles of the _Actinia mesembrianthemum_ are generally of a
beautiful rosy-pink, and the body of a rich warm brown. But of all the
species, _A. crassicornis_—represented in the lower part of Plate X.—is
perhaps the handsomest, the orifice or mouth being of a delicate straw
tone, the tentacles white, variegated with bands of delicate pink, and
the body, or stem, a rich orange-brown, thickly sprinkled with tubercles
of bright yellow. This fine species sometimes measures five inches
across, when the tentacles are fully expanded.

When the _Actiniæ_ are in a state of repose or sleep, the tentacles are
entirely drawn in, and the stem or body closes over the orifice, leaving
only a slight indent to mark its existence. In this state they might be
mistaken for short-stemmed fungi, the pale-bodied species being very
much like a half-grown mushroom, if one can imagine it placed close to
the ground, without any visible stem.

Most of the species can be easily detached from the rocks to which they
are found adhering, but in some cases it is found necessary to cut out
the portion to which they cling, by means of a hammer and chisel. But
when this is done, and they are placed in the Aquarium, they often
willingly leave the stone to which they are attached, which they would
not do by gentle persuasion, or any moderate amount of force; and they
then take up their station on some suitable portion of the artificial
rock-work, just as those do that have been originally detached from
their native rocks. Above twenty species of _Actiniæ_ are known to
British naturalists.

 [Illustration: PLATE IX.

 1. Actinia anguicoma.
 2. Cucumis hyalinus.
 3. Echinus sphæra.
 4. Alyconium digitatum.]

The _Lucernariæ_ are another class of Zoöphytes, or plant-like
creatures, as the term _Zoöphyte_ implies, being formed of the Greek
word, _Zoön_ (ξωον), signifying a thing possessed of animal life, and
_phyton_ (φυτον) a plant. This general term is applied to all the
creatures—some of very distinct character—that belong to this class,
which forms a separate division of natural science, known as
Zoöphytology.

The species of _Lucernaria_, which has received the specific
denomination of _auricula_, from its slight resemblance in form to the
flower of that name, is delineated in Plate VIII., attached to a slender
branch of sea-weed, just above the two large Sea-Anemonies. This species
of _Lucernaria_ is generally of a light pinkish colour, and is, in
general form, perhaps more like a Convolvulus than an Auricula. Two
species have been most beautifully delineated in all their details by
Mrs. Johnston, in her husband’s magnificent work on British Zoöphytes.
These drawings are, in fact, so charmingly and, at the same time,
accurately executed, that it would seem that the pencil ought to be
guided by delicate female fingers when portraying these
minutely-intricate and unusual forms of animal life. The exquisite
drawings by Mrs. J. E. Gray, in her work on the curious molluscous
animals, whose habitations alone, the beautiful sea-shells of our
cabinets, were, till recently, all that was known of them, afford
further evidence, if it were needed, of the aptitude of the more
finely-strung female capacity for this department of scientific
portraiture. The name of Mrs. Griffiths is also honourably associated
with the study of natural science, especially that connected with our
marine _Algæ_—a beautiful division of sea-weeds—having received its name
Griffithsia, in honour of the esteemed services of that accomplished
lady.

The _Lucernaria campanulata_, which is of a somewhat more bell-shaped
form than the preceding, is of an uniform liver colour; and in the
hollow of the flower-like cup the “mouth” projects, in a square form in
the centre. There are three known species of British _Lucernariæ_, which
would all form highly curious objects in the Aquarium; but they are
excessively delicate and fragile creatures, hanging suspended from the
object to which they are attached, when taken out of the water, like a
mere lump of jelly, and would doubtless be very difficult of transport,
and probably not capable of retaining life in a state of confinement,
except for a short time.

The “compound Zoöphytes,” or, more properly, _Polyps_, as being, as it
were, many creatures in one, are still more curious than the two classes
just described. A common example of this class is the _Alyconium
digitatum_, looking like a mass of short fingers, when the final florets
are closed, as its specific name imports, being sometimes called, by the
fishermen of our northern coasts, Dead-men’s-toes. Each finger-like cell
contains a separate creature, whose tentacles, when expanded, form the
floret, after the manner of those of the Sea-Anemonies, but yet each
separate creature is vitally attached to a central polypidom, or spine,
which binds the whole group into one existence.

Of this class are the curious _Pennatulidæ_, one of which is commonly
known as the Sea-Pen. The three species of this class of _Polyps_ known
to inhabit the British seas, are so distinct from each other that they
form at the same time three distinct genera. The most beautiful of the
three is the _Pennatula phosphorea_, the Sea-Pen, which is not uncommon
on some parts of our northern coasts. It is represented in Plate VII.
The purple branches, or pinnæ, of the upper portion, form the feathered
part of the quill pen to which it is likened; the bare portion of the
polypidom below having certainly some resemblance to the quill. This
curious zoöphytic form is often seen in an erect position, planted, as
it were, in the mud like a miniature purple Pine, though it is capable
of motion through the water from place to place, by some action of its
organs which has not been accurately detected. It is one of the
handsomest of our British Zoöphytes. The polypidom, or trunk, is three
or four inches long, fleshy, and of a purplish red. It is naked at the
lower end, and feathered above with long, closely-set pinnæ, along the
margins of which the polyp-cells are placed. The pinnæ are curved
backward, and capable of either separate or united motion. They are
supposed by some to be capable of the action of regular oars; but this
is very doubtful, though their bearing on the polypidom, which is
strengthened by an internal column of calcareous or bony matter, would
give them considerable power for that purpose. The creature’s specific
name, _phosphorea_, must not lead to the supposition that it always
emits a phosphorescent light, for it is only when irritated that this is
produced. If plunged into fresh-water, it scatters a shower of
phosphoric sparks in all directions, which forms a magnificent and
curious spectacle, far more brilliant, no doubt, than the fabled hues of
the dying dolphin.

The _Virgularia mirabilis_ is another of this class of creatures, almost
as elegant as the Sea-Pen, but more slender, and in the form of a
branching rod, as its name imports. (See Plate VIII.)

The Sponges form a curious class of Zoöphytes, which have perhaps a much
closer affinity to plants than any other. They are occasionally very
sportive, and curious in their forms; and Dr. Johnston enumerates
fifty-six species belonging to our coasts; they are, however, unsuited
to the Aquarium in the present state of our knowledge; and when portions
of rock are collected on the shore, for the tank, care should be taken
to clear off any Sponge formations that are perceived, as their certain
and rapid decay would be liable to injure the condition of the whole
colony of the Aquarium.

[Illustration]

------------------------------------------------------------------------




                              CHAPTER VI.

                           THE MOLLUSCS, ETC.


The curious floral forms of the Zoöphytes have, as yet, attracted the
greatest degree of attention among the constructors of marine Aquaria;
yet other forms of ocean life offer equal, if not superior,
opportunities for curious observation, and are equally well calculated
to bear the confinement of the tank. Among them all, none more than the
Molluscs, especially the shell-bearing division, which merits the
careful attention of the student of Nature, as forming some of her most
singular manifestations.

The knowledge of the nature and structure of many of the most curious
shell-bearing Molluscs is of very recent date, with the exception of
those which possess obvious qualities which have fitted them for
articles of diet or commerce; such as the Oyster, Mussel, Cockle, &c.,
as eatable species—and the Purples, Sepias, and Cuttle-fish, as
containing valuable dyes. With the exception of such as these, the
pearl-yielding Bivalves, and a few others, nothing was known, with a few
remarkable exceptions, of the animals that create and inhabit the
beautiful shells that have so long been ranked among the most elegant
objects of the cabinets of the curious. Many of these were, in fact,
scientifically classified by learned naturalists before the nature of
the animal, of which they formed the mere senseless husk, was even
guessed at. The ordinary collector did not even desire to know anything
of the creature which produced the shell he most prized; it was
sufficient for him that it was estimated as “rare” by his brother
collectors—rarity being a quality more highly prized than even beauty.
With this feeling, prices as great were given for single shells as ever
enthusiastic Hollander paid for a coveted bulb during the height of the
Tulipomania. No amount of guineas was too much, at a sale of shells, for
such a contested prize as a _Many-ribbed harp_, a _Gloria maris_, a
_Cedo nulli_, or a _Voluta Junonia_. But that race of idle
shell-fanciers has given place to a race of true conchologists, who are
investigators as well as collectors, and whose labours are daily
developing unexpected and valuable knowledge from those long obscure
pages of the great book of Nature.

The marine Aquarium may be made the means of many curious discoveries
regarding the habits and organization of the shell-bearing Molluscs;
and, with this feeling, I may direct the attention to several of their
singular characteristics, in order that they may serve as clues to the
detection of others.

The term Mollusc, from _mollis_, soft, is intended to express that the
whole class are invertebrate; that is, entirely without spine, or any
bony support to their curious fleshy forms. The term was invented by the
illustrious Cuvier, but is objectionable as a distinctive one, the
characteristic on which it is founded being shared by other distinct
classes of animals. When, however, the application of a term is well
understood, its inner signification becomes unimportant; it is,
therefore, now too late to criticise the one invented and applied by the
prince of modern naturalists.

Among the interesting facts detected by recent science, it has been
shown that many of the seemingly shapeless masses of soft substance,
scarcely to be termed flesh, possess all the senses of the higher
animals. In the _Cephalopoda_, the organs of sight and hearing are both
well developed; and Professor Owen considers that the Nautilus possesses
even an organ of passive smell. The _Gasteropoda_ too, are, according to
Siebold, nearly all furnished with ears and eyes, the former organs
being described as forming round capsules, conspicuously visible near
the roots of the tentacles.

Some of the _Conchifera_, also, are furnished with numerous eyes, which,
like those of the Scallops and Clams of our own shores, are also placed
among their tentacula.

It appears probable, says Dr. Johnston, that many have also the sense of
taste, as they are observed to select particular articles of food in
preference to others, and there is no other sense that appears fitted to
regulate the choice. The mouth, as it is termed, of many of the
molluscous tribe is furnished, as among the _Gasteropoda_, with a fringe
formed of filaments, which may be organs of touch, and they have also a
complicated breathing apparatus.

The strength of these boneless creatures is something very
extraordinary, and almost incomprehensible. The _Strombus gigas_, a
soft, snail-like creature, carries a shell which often weighs more than
five pounds; the _Cassis tuberosa_ supports one nearly as heavy, and the
naked Molluscs, that have no shell to carry, have other modes of
exhibiting strength of a very extraordinary character.

The shells of the clothed Molluscs are senseless, being permeated by no
vessels, and are formed by the animal itself from a secretion with which
its outer integuments are invested, and which may be described as lime
in a state of solution. The thickened edge of the mantle, by means of
which the form is given to the shell, and the general manipulation
effected, is furnished, as may be seen with the aid of a moderate lens,
with a minute and highly sensitive fringe, the cilia of which are of
various colours, corresponding in tone and position to the tints which
decorate the exterior of the shell. The coloured cilia or fringes have
doubtless a dyeing power, which colours the calcareous solution at the
time it is added to the shell by their plastic instinct. The solution
becomes a hard testaceous substance so soon as it leaves the body of the
animal, and is deposited in architectural layers upon the beautiful
structure of the shell, by the “trowel” and “brushes” of the edge of the
mantle.

This process is beautifully described in Jones’s “Animal Kingdom,” with
all the details relating to the successive ridges on the shell, which
mark the age of the animal; it having been ascertained what time is
required for the completion of each story of the edifice.

The power of locomotion is one of the most curious subjects for
observation in the structure of shell-coated Molluscs, and for this
purpose the marine Aquarium offers many advantages. Other classes of
animals have been distinguished by the number of their feet; we have,
for instance, a tribe of worms termed centipedes, or hundred-footed
creatures; and, to pass over many gradations, to the superior
grass-feeding and carnivorous animals, we find them termed quadrupeds,
or four-footed creatures; while the human race, along with birds, has
been termed biped. Why, therefore, may we not coin a word for our
present purpose, and call these curious Molluscs monopeds, or
single-footed creatures?—for they walk with a single foot, being
compelled to do so by the very simple fact that they have no other. This
limb, or foot, being gradually protruded, its bearing against some
substance forces them forward, and when the foot has attained its full
distension it is drawn in, and a new bearing obtained, and by the
repetition of this process, a certain amount of locomotion is effected.
Some species float on the surface by means of this foot. Having crawled
up a rock to the height of the surface of the water, the foot is
protruded and exposed to the air, when it becomes suddenly dried, and in
that state serves as a cork, which enables the animal to float away
close under the surface of the water. But if any agitation of the water
wet this floating apparatus, or the animal withdraw it voluntarily
beneath the water for that purpose, the creature immediately sinks to
the bottom.

The swimming power of this race of creatures is equally curious. The
_Cephalopoda_, by the ejection of a jet of water, propel themselves
rapidly in the opposite direction, and by the repetition of the jet at
regular intervals, a beautiful power of motion is obtained, as regular,
and with less labour than that of ordinary swimming by means of the
action of fins or other oar-like limbs adapted to the purpose.[3] The
_Pteropoda_, however, in their little shells, translucent as glass, swim
by the action of small fin-like paddles placed near the head.


[Footnote 3: Some species effect leaps by an analogous
contrivance—collecting water within the closed mouth, and then emitting
it at a gush from a small portion of the aperture, suddenly opened,
which propels the creature to a considerable distance, as it were, at a
single bound.]


The _Bivalves_ do not make so clever a use of their single foot as the
_Univalves_. The foot in this tribe appears to be furnished with a
terminal hook, which, when the foot is protruded, clings to some
substance, and the animal is drawn up to that point, when the operation
has to be repeated; this appears likely to produce but a slow rate of
progress, yet some of the sand-boring _Bivalves_ manage, when alarmed,
to conceal themselves with great rapidity by that means.

The _Mollusca_, as feeders, are divided into three classes—those which
take only liquid food, the vegetable feeders, and the carnivorous
species.

Those which are only able to take food in a liquid form, are such as
have no means of seizing prey, their food consisting of the countless
myriads of infusorial animalcules which float in the sea-water, and
which are carried into the orifice of the stomach or mouth by the
current. Of these, the _Dunicata_, _Brachiopoda_, and _Conchifera_, are
examples.

The liquid feeders exhibit a very low form of molluscous life, but other
classes are furnished with means of defence and aggression, equal to
those of terrestrial quadrupeds, and much more extraordinary in their
form. Some of the carnivorous _Univalves_, for instance, feed upon the
_Bivalves_ by drilling a hole through the solid shell, and withdrawing
the animal piecemeal, as required.

The _Eolis papillosa_ has been observed tearing away the tentacles of
different species of Sea-Anemone with extraordinary voracity, and the
tribe must therefore very evidently be excluded from the Aquarium. The
Cuttles, also, are to be avoided from the same cause; they are fierce
tyrants of the deep, that would make sad havoc among the delicate
creatures with which we delight to furnish our tanks of glass. The
curious substance termed Sea-Grapes, which are the eggs of this
creature, might, however, be placed in the tank, and the progress of
development watched, without fear of injury to the other inmates.

The full-grown Cuttle is, nevertheless, so curious a creature that, in a
tank prepared with that special view, his habits might furnish food for
much curious observation—indeed, carefully fed up, he might form very
excellent food himself; his German name, _Kuttel_, signifying tripe, the
flavour of which his flesh is said to resemble. The common Squid, which
is eaten by the poor of our coasts, is a kindred species, and is also
said to have a similar flavour. Molluscs of this class, as well as the
disgusting-looking Poulp, or many-feet, are seen in profusion in the
markets of the south of Europe, and are as highly prized as the Oyster
with us. The ancients carried their taste for them so far as to feed
them up artificially; and at the nuptial feast of Iphicrates, one
hundred _Polypi_ and _Sepiæ_, as we are informed, were disguised with
different sauces, each imparting a different flavour. The land Molluscs
were also much sought as a table delicacy, a species of the large
Garden-Snail being bred for that purpose, and fed upon a prepared paste,
which so accelerated their growth that we learn, from the industrious
Pliny, of their attaining to enormous dimensions; the shells of some of
the finest being capable of holding eighty measures of water, called
quadrants. But in speaking of Molluscs, I must principally confine
myself to such as are suitable for an Aquarium.

Among the Sea-Snails of our own coast, which are still eaten by the
lower orders, is the Periwinkle, considered by some superior in flavour
to the Oyster or Shrimp. This creature, the _Littorina littorea_, is one
of the most useful creatures in an Aquarium, cleansing it from all
decaying vegetation, which is its natural food. The Periwinkle varies
much both in size and colour, the ground tone of the shell being
sometimes red, orange, or even scarlet, sometimes with and sometimes
without handsome black bands. Such as are coloured in this attractive
manner should obviously be selected as inmates of the Aquarium, in
preference to the dull-coloured varieties; and a few of the small yellow
kind, _Littorina littoralis_, may be added by way of variety, though
they do not succeed so well in confinement as the other species.

The Whelk, _Buccinum undatum_, another of the snail-like Molluscs of our
coasts, which is considered good eating by the lower orders, and often
seen on fish-stalls at particular seasons, is well worthy a place in our
miniature sea; especially under certain circumstances, when the shell of
this creature assumes a most singular aspect, well calculated to excite
the wonder of the young naturalist. It is sometimes found surmounted by
a mass of living substance, which might be taken for the body of the
creature, residing in preference on the roof of its dwelling during the
summer months, as it may be observed spreading a set of tentacles, from
a mouth-like orifice, for the collection of food. Within, however, a
pair of protruding eyes are seen glaringly on the watch for prey, and
another set of food-clutching machines may be noticed beneath them,
ready for their work, and only awaiting the opportunity. They look much
like the claws of a lobster, and if any suitable object comes within
their reach, it is seized by one or both of these two-fingered hands,
and carried to the yawning mouth beneath; but before it reaches that
evidently impatient receptacle, a brightly-shining crimson finger,
ornamented with two white stripes, darts from beneath those claws and
mouth, and, snatching away the rich morsel, disappears as suddenly as it
came, leaving the expectant mouth and astonished claws both empty. The
mystery of this seemingly compound creature having, as it were, a
first-self living outside the house and getting a separate living, a
second-self located in the front parlour, and prevented from eating its
own dinner by a third-self residing in the back parlour, may be easily
explained, now that the persevering observations of our naturalists have
solved it. It is as follows:—

The internal dweller in the front parlour is the Hermit Crab (_Paguras
Prideauxii_), a creature seldom contented with its own pretty solid
habitation, but ever seeking some further protection, which it generally
finds in an empty Whelk-shell. It is, moreover, very particular as to
_fit_, and other details; for it has been observed, when looking out for
a house, to try and reject many before finally adopting an abode. The
inhabitant of the back parlour is the Sea-Worm, _Nereis bilineata_, a
creature which, instinctively knowing the voracious propensities of the
Crab, and determining to share his abundant feasts, seizes his
opportunity, when mine host of the Whelk-shell is pretty well surfeited
and in a semi-dormant state, to sneak past the dangerous claws into the
“back parlour,” which is the interior of the narrow spiral of the
shell—a form of apartment which affords him a most comfortable and
convenient home, in which, by the superfluous voracity of the Crab, he
is furnished with board as well as lodging. The external tenant of the
Whelk-shell is a parasitic Sea-Anemone, known as the Cloak-Anemone, from
its power of nearly enveloping the object to which it attaches itself,
by means of the extension of its stem or body. It is known in scientific
classification as _Adamsia palliata_, having been made a separate genus,
and its specific name ingeniously taken from that of the Roman cloak,
the well-known pallium of the classical writers.

Almost invariably, when the Hermit Crab is discovered inside the
Whelk-shell, the _Adamsia_ is found outside; and the Hermit is seldom
without his dinner assistant, the prettily-striped _Nereis_. This fact
is so well known to fishermen, that when in search of this worm, which
is an excellent bait, they never fail to break the shells tenanted by
the Hermit Crab, and are seldom disappointed in finding the object of
their search in his company.

Another parasitic Anemone, still more fond of travelling, the _Actinia
parasitica_, often selects the back of the Crab himself (generally
_Paguras Bernhardus_), and in that position is hurried along, in the
sidling gallop of his steed, in a way that must often prove
inconvenient; for in passing under ledges of rock, the Crab, doubtless,
only takes his own measure. Yet, in such cases, the Anemone probably
knows how to take care of himself; and when _Bernhardus_ becomes
skittish and adventurous, “draws in his horns,” as many other bold
spirits are obliged to do at certain crises of their career; and in this
state, presenting only a semi-spherical mass of tough leathery
substance, he can fearlessly allow himself to be driven beneath stony
archways, or under impending branches of the marine forests, by his
ferocious Jehu, with less chance of injury than the outside passenger of
a terrestrial stage-coach passing beneath the low gateway of some
inn-yard.

Our largest native shell of the Whelk tribe is the _Fusus antiquus_,
often used by the Shetland islanders as a lamp; for which purpose it is
suspended horizontally, the cavity holding the oil, and the wick
projecting from the canal.

The Whelks belong to the interesting family _Muricidæ_, some of which,
natives of our own coasts, are very pretty objects for the Aquarium. It
was the _Murex trunculus_ which yielded the Tyrian purple, different
species affording distinct tones of colour. In form, these shells are
somewhat like our common Whelk, but finely marked with broad, dark,
spiral stripes. The ancient mode of extracting the dye, as described by
Pliny, was verified by Mr. Wild, in 1838, in a very interesting manner.
In the neighbourhood of the site of the ancient Tyre, he found, in the
rocks on the sea-shore, a vast number of round cavities, evidently the
work of the hammers and chisels of long ages past. These cavities varied
in size, from that of a small flower-pot to that of a cauldron, and
round about them still lay scattered immense masses of the remains of
the shells and bodies of the _Murex_, in many instances aggluminated
together. They had evidently been pounded in those cavities, exactly as
described by Pliny, and the dye extracted according to the formulæ so
graphically detailed by the ancient naturalist.

The _Purpura lapillus_ of our own shores yields a similar dye, and may
be kept in our Aquaria as a reserve bottle of “marking-ink;” for the
ingenious Mr. Gosse has shown how its dye may be thus used for household
purposes. The shell is a small white univalve, with one or more bands of
pale brown. It perishes on being immersed in fresh-water; and a thick
vein of yellowish white, near the head, contains the dye, which is a
liquid of a creamy thickness and of pale, indistinct colour. But if it
be painted in the forms required, as a cipher, or any other ornament, on
linen, or any other textile fabric, with a camel’s-hair pencil, and
exposed to the air, it rapidly assumes a yellow tone; which first
changes to green, then blue, till at last it becomes a full strong
indigo, exhibiting plainly all the forms that have been traced. A
crimson-red change next ensues, and the final colour, which is indelibly
permanent, is a reddish purple.

There is also a large naked Mollusc, one of the _Aplysia_, that pours
forth, under excitement, a secretion of rich purple hue; but the colour
is considered valueless as a dye, from its extreme volatility, though it
is stated that it may be rendered permanent by means of nitric acid.

The common _Planorbis corneus_, a shell coiled in the form of a ram’s
horn, has a similar property; but the colour of the fluid is still more
volatile. The purple liquid, however, contained in another of our native
shells (_Scalaria_) is very permanent.

It is well known that the ink of the Chinese, which we term Indian ink,
is prepared from the Cuttle, and the Cuttles of the Mediterranean Sea
furnished the principal black inks and dyes of the Greeks and Romans. It
is a kind of _Sepia_, in fact, that still furnishes the rich brown
colour which bears the name of the animal from which it is derived.

The common _Sepia vulgaris_ might form an appropriate specimen for a
marine Aquarium, many of its habits being singular; and its power of
enveloping itself in a cloud of its own rich dye may often be observed
when it is irritated by the presence of a real or fancied danger. It has
the faculty of propelling itself hither or thither by the emission of a
jet of water, as described in speaking of the locomotive power of other
Molluscs, with the additional faculty of guiding its motions by the
rapid movement of two fin-like paddles, which, when in agitation,
produce an effect not unlike the fluttering action of the wings of a
moth. This little _Cephalopod_ has large projecting eyes, and a group of
arms that hang listlessly down when the fins are in motion. It changes
colour fitfully and beautifully, exhibiting in the course of such
changes pretty metallic spots and rings, which appear and disappear, now
like gold, now like silver, as seen through a semi-opaque substance. The
whole creature is at one moment of a dusky gray tone, but fitfully
changes to white or deep brown when alarmed. These little creatures are
exceedingly voracious, and when one was observed by Mr. Gosse to seize
another of its own species, the victim shot out its defence of dark
black fluid.

Some of the _Trochus_ tribe of shells look pretty in an Aquarium, but at
present their treatment is so imperfectly understood, that they do not
seem to do well. The specimens can, however, be renewed as required.

_Trochus ziziphinus_, the pearly _Trochus_, the animal of which is of a
rich orange colour striped with black, moves freely about, and forms a
very attractive object. The animal of _T. granulatus_ is larger and
handsomer, but shy, and displays little activity in confinement. The
small _Trochus_, _T. cinerarius_, if placed in an Aquarium, may be
observed rasping down the minute Confervæ that grow on the inside of the
glass; and the curious method of the operation, and the singular
instruments with which it is performed, may be observed by the aid of a
small pocket lens.

_Limpets_—those curious bonnet-shells, as they are termed in some
places, which are found in the form of a flattened and inverted funnel,
adhering closely to the flat rocks of the sea-shore in all the European
seas—are more curious than they appear at a first glance, and have
characteristics that well repay the labour of persevering observation. I
should always place a few in an Aquarium.

The common Limpet (_Patella vulgata_) has a power, which appears
extraordinary when the soft substance of its body is considered, of
excavating, more or less deeply, a portion of the rock which it makes
its home. It is supposed to leave its hollow in the night, returning
infallibly to its home in the morning. This habit might be watched in an
Aquarium, and, if verified, a very interesting fact would be
established, which at present remains somewhat doubtful, although Mr.
Lukis, of Guernsey, marked a Limpet, and found it return to its haunt.
These creatures belong to the order named _Cyclobranchiata_, from the
breathing apparatus being arranged in a circle round the body. The
pretty British shell, vulgarly called the Ark of Noah, but which is the
_Arca tetagrona_, should be tried in Aquaria, as well as the elegant
Heart-shell of the beautiful genus _Isocardia_; the movements and habits
of the latter, as described by the Rev. J. Bulwer, being very curious
and interesting.

The pretty little Cowry is an object that must not be passed over in
silence, when treating of objects fitted for the marine Aquarium,
although, in a little book of this extent, many others must of necessity
be omitted. This beautiful little creature, _Cypræa Europæa_, carrying
its porcelain-like dwelling on its back, is enabled to move steadily
along by the action of its single foot. When in action, the mantle, as
it is termed, which is the general covering of the body, is greatly
distended, and protrudes from the shell, which it perfectly encloses,
folding up at the sides, and meeting at the top, the joining being
scarcely perceptible, and the whole surface fitting so tightly to the
shell, that the little ribbings are seen distinctly through it. It is
curious to observe the act of respiration, and all the associated
phenomena of this wonderful little animal. The foot is pale orange, the
mantle delicate olive, spotted with black and studded with protruding
glands of yellow. It is, in short, when in a state of activity, a most
curious and beautiful creature, of whose appearance and habits
thousands, who only know and admire the deserted shell, can have no
idea.

The bivalves, of which all are acquainted with at least one kind—the
delicious edible Oyster—offer many animals suited to Aquaria. The
curious Razor-shell, but for its habit of burrowing, would form a very
curious object; and the Cockles, from the rich colour of their beautiful
fringes, when the shells are partially opened for feeding and breathing,
are very beautiful objects.

The means of movement of the common Scallop, or Cockle, and other
bivalves, by means of a single fleshy “foot,” have been described in
speaking of Molluscs in general; but the spinous Cockles, _Cordium
aculeatum_ and _C. tubercutum_, have been termed the aristocracy of the
Scallop tribe. The valves of the largest open three-quarters of an inch,
and the visible portion of the spongy-looking fleshy mantle is of a
pellucid orange colour; at the end is protruded a double tube, thick and
short, enveloped in a fringe of cirrhi or tentacles. The foot, which has
been compared to a tongue, is smooth, glossy, and semi-transparent, like
scarlet cornelian, and enables the creature to move about with great
activity in an Aquarium; some that were sent, by the Rev. C. Kingsley,
to Mr. Gosse, having startled that gentleman by the noise they were
creating among the pebbles and other objects of his tank, by their rapid
movements.

Many other kinds of shells might be mentioned if space permitted, but I
must content myself with mentioning, _en passant_, the polished _Donax_,
which, when the animal displays itself, exhibiting its bright yellow
colouring, with its curious stripes and gay pink fringes, would form a
real ornament to the drawing-room sea; and just hinting at the
introduction of a specimen of the _Tritonia Hombergi_, remarkable for a
power of producing an audible sound like the click of a steel wire.

The pretty little bivalve, the _Lima hians_, also forms a very
attractive addition to the Aquarium, especially in motion, when its long
orange fringes form a train or tail like that of a fiery comet, as Dr.
Landsborough has observed, as it glides along, propelled by the
discharge of a jet of water, the mechanism for the propulsion of which
forms its swimming apparatus.

[Illustration]

------------------------------------------------------------------------




                              CHAPTER VII.

                THE ASCIDIANS, BARNACLES, SEA-CUCUMBERS,
                    NAKED MOLLUSCS, SEA-WORMS, ETC.


A group of _Ascidians_ forms a very curious object for the Aquarium,
their forms being singular, and sometimes delicate as a transparent
egg-shell. The group delineated in Plate VII. will convey some idea of
the general appearance of these creatures, whose habitations might be
taken for a store of fairy pitchers, placed snugly in their submarine
china-closet for extra safety, and partially covered with sea-weed as a
further means of concealment. There are above fifty native species,
varying greatly in appearance. They may be found at the extreme verge of
low water, many having the aspect of pellucid bags, formed of a
substance between jelly and leather; while others present a far more
robust and rugged appearance, both in form and texture. Some are very
dingy in colour, but a few species—more rarely found—are very
attractive, and sometimes brilliant, in their hues.

 [Illustration: PLATE X.

 1. Actinia crassicornis.
 2. A group of Serpula contortuplicata.]

The Barnacles must not be omitted in furnishing an Aquarium, nor the
fable connected with the Common Barnacle (_Pentelasmis anatifera_), in
which it is affirmed that the Barnacle Geese were their offspring. Our
old naturalist Gerard not only gives a detailed account of the
transformation by which this wonder of the good old times was
accomplished, but positively illustrates his description with an
engraving, in which the metamorphosis is seen in progress.

The tube-like cells of the _Serpulæ_ have some resemblance to the cells
of the Common Barnacle, but that of the solitary Serpula, _Serpula
tubularia_, is much taller, often rising a foot from the substance it
adheres to. The fan-like feathers forming the feeding, and, perhaps,
also the breathing apparatus, of _Serpula contortuplicata_, are
exceedingly rich in colour, as is also the member which acts as a “cork”
to the tube when the feather-like tentacles are withdrawn, and which is
familiarly termed the “stopper;” for when, on alarm, the feathers are
suddenly drawn in, the “stopper” immediately follows, shutting up the
opening of the tube in a very perfect manner. This organ is often of a
rich orange, and the feathers a brilliant scarlet, though they are
sometimes pale, or nearly white, as shown in Plate X. These fan-like
organs, termed feathers, appear to act as breathing organs, by
separating the oxygen from the currents of water which pass between
their fibres. The _Sabella_, an allied tribe, forms its tube of mud;
while that of the _Serpula_ is always of hard shell. The golden-combed
worm, _Amphitrite auricoma_, another singular creature of this class,
may be best alluded to in this place. Just below the cork-like head,
when it leaves its tubular shell, are the scarlet gills, slightly
resembling those of fishes, and across the head the golden comb-like
appendage is expanded, from which it derives its popular name. When the
animal retires within its tube, the upper part of the head has, like the
_Serpulæ_, all the appearance of a cork or small stopper. This creature
is one of the most curious of its class.

The _Balani_, or Acorn-shells, which are generally parasitic, fixing
themselves to the shell of the Whelk or some other univalve, spread
their crimson tentacles when seeking food exactly in the manner of the
_Serpulæ_, the feathery filaments forming a kind of living casting-net,
as it has been observed, in which the minute _Annelid_ or _Infusory_ is
entangled and devoured. Two _Balani_ are represented in Plate VII. on
the shell of a common Whelk.

The _Holothuriadæ_, or Sea-Cucumbers, are very singular creatures; their
form, as it floats in the waters, exhibiting as good a miniature
representation of a small pickled Gherkin as can be conceived, except in
colour, the shells or cases of these animals being generally white. One
of the species, _Hyalina_, has a case which seems formed of crisp
rice-paper, and is covered with spines of the same colour and texture.
The tentacula, or breathing apparatus, eight in number, are curiously
branched, and, when expanded, have the appearance of a skeleton flower,
of which the figure in Plate IX. will convey a tolerable idea. The
functions of this flower-like set of organs are probably the same as
those of the _Nudibranch_ class of _Molluscs_, which, though generally
considered as being a breathing apparatus, are, probably, at the same
time food-collecting organs, as all the creatures thus furnished are
liquid feeders.

_Thyone papillosa_, one species of Sea-Cucumber, has ten branches to
this set of organs, which it seldom displays when in captivity; but a
little gentle motion artificially imparted to the water, as suggested in
another place, would probably produce the kind of excitement requisite
for their expansion, as the introduction of fresh water to the tank
seldom fails to produce this effect for a time. When irritated, these
creatures have the capacity of committing self-destruction in a most
determined and complete manner, by expectorating the whole of the
intestines and leaving their case or shell bare and empty. But Sir J.
Dalzell has observed that the shell thus deprived of its living inmate,
must be much more intimately connected with its life and organization
than the shells of the Molluscs; for after a considerable lapse of time,
he observed that the rejected parts have been renewed by gradual growth.
The introduction of a single drop of fresh water will at once drive the
creature to this summary mode of putting an end to the inconvenience.


                  OF THE NAKED OR SHELL-LESS MOLLUSCS.

The Sea-Lemon, _Doris tuberculata_, is one of the most attractive. It
derives its popular name from its peculiar form, which is like that of
half a Lemon cut longitudinally. It is generally of a yellow tone of
colour also, which greatly adds to the fancied resemblance. It has its
breathing apparatus exposed externally, like other Nudibranchs,
spreading over the mantle, near the head, in a flower-like shape; and,
as it moves slowly round and round the Aquarium, forms a very singular
object.

The _Doris pilosa_ is a pretty white species of the same order; and the
little black shining Nudibranch, _Runcina Hancoci_, is a pretty and
interesting creature. But the handsomest of the Nudibranch or
naked-gilled tribe, as the term might be Englished, is the _Eolis
corronata_, which forms certainly a splendid ornament to the Aquarium.
Its general colour is a pellucid indistinct tone, of pinkish hue, the
papillæ or branchiæ are in clusters, and the central canal is of a rich
crimson. Different parts of the surface reflect the brightest metallic
colours, and the whole creature has a very gem-like appearance. In
captivity it is very active. Another species of _Eolis_ has the power of
making a singular clicking noise, like the _Tritonia_.

The _Aplysiæ_, or Sea-Hares, have been unenviably celebrated among their
congeners as containing a virulent poison. The species common in the
Mediterranean, _A. Leporinæ_, furnished the venom with which the
infamous Locasta destroyed the enemies of Nero; and with which she
eventually prepared, at the tyrant’s request, a draught for himself, but
which he had not the courage to swallow. The British species, _A.
hybrida_, might probably be kept in confinement.

Many of the Sea-Worms are very beautiful. The _Nereis bilineata_ is very
brilliant, with its crimson body brightly marked by two white
longitudinal stripes.

The _Phyllodoce_ are a class of Sea-Worms, somewhat resembling the land
Centipede, which form curious objects of observation when they are in
search of food. Instead of spreading a set of tentacles, like some of
the Zoöphytes and Molluscs previously described, they have the faculty
of turning the cavity which forms the stomach inside out, like a
stocking, the inverted organ protruding from its mouth to a considerable
distance, which, when it becomes sufficiently covered with the minute
Infusoriæ which form its food, is drawn in, assuming gradually its
natural position, where it remains till the nutriment so introduced has
been absorbed, when the operation is repeated.

The Sea-Mouse, one of the largest and commonest of our marine worms, is
of a flattened and somewhat oval form, pointed at each end, its general
colour being pale brown. The clothing of silky hairs, however, with
which it is invested, is so splendid, glittering in iridescent colours
like the plumage of a humming-bird, that Lamark has appropriately named
it _Halithea_, or Sea-Goddess—Linnæus having previously given it the
name of _Aphrodite_, the Marine Venus. When, indeed, it receives the
rays of light, and reflects them from the depths of the sea, rich with
prismatic hues, the effect has been compared in splendour to that of the
peacock’s tail when outspread in the sunshine. When in the Aquarium it
crawls restlessly to and fro, as though anxious to exhibit its
splendours in every possible point of view; the metallic tinges,
changing with every position, being most magnificent by candle-light,
when red and orange hues predominate, while by day-light pearly greens
and blues are most frequent.

The bodies of many of the _Euricidæ_ and _Nereidæ_ exhibit changing
colours of similar character, though less splendid; but many of them
possess an opal-like tenderness and delicacy almost equally attractive.

The little Sea-Slug, _Ægines punctiluceus_, is a brilliant little
creature, well worthy the trouble of being permanently established in
our Aquaria. Its general colour is pale reddish-brown; but, with the aid
of a moderate lens, it exhibits a number of small black tubercles, in
the centre of each of which is a speck of resplendent blue or green,
forming a succession of gem-like ornaments that have been compared, by
enthusiastic naturalists, to sapphires and emeralds; but, without
exaggeration, the jewelry of this little creature may be said to surpass
that of the Diamond Beetle, notwithstanding his superior reputation.

A few _Chitons_—a sort of Sea Wood-Louse—would do well in a tank; and a
specimen of _Gastrophæna modolina_ is said to have thriven well during
many months.

[Illustration]

------------------------------------------------------------------------




                             CHAPTER VIII.

               THE FISH AND CRUSTACEANS OF THE AQUARIUM.


A marine Aquarium may be rendered very interesting without the
introduction of fish, and as their presence requires that the water
should be once each day aerated by means of additional water, introduced
by the syringe or by a drip, continuing for some time from another
vessel, many may prefer the lovely Sea-Weeds, curious Zoöphytes, and
beautiful Molluscs, alone; as, if the balance between the amount of
animal and vegetable life be felicitously balanced, and the natural
scavengers, in the shape of Periwinkles and other Sea-Snails, for the
consumption of decaying vegetable matter, and a few Prawns to perform a
similar office for perishing _Infusoriæ_, or any other animal matter, be
properly supplied—the tank may remain for a long time undisturbed, the
supply of oxygen being ample for the lower classes of animal life
alluded to. The beautiful _Actiniæ_, indeed, will exist in apparent
health for a considerable time in water in which no vegetable growth has
been introduced. Mr. Gosse describes instances in which the water in
glass Aquaria, containing Sea-Anemonies, has remained perfectly pure for
more than a year.

The addition of fish, however, undoubtedly enlivens the general aspect
of an Aquarium very considerably; and many may not grudge the task of
daily aerating the water, in order to enjoy the cheerful spectacle of
their agreeable and ever-active movements. One or two young Flounders,
very small, and the young of other species of flat fish, add much
interest to an Aquarium, in consequence of their mode of swimming being
so different to that of the class of fishes with whose movements the eye
is more familiar.

Among the fish mentioned by the most experienced in the keeping of Sea
Aquaria as best suited to that purpose, the first is the pretty little
Tansy, _Blennius pholis_, with its bright scarlet eyes, and the many
changing hues of its body. This little fellow will live and flourish in
a tank with a poorer supply of oxygen than any other fish yet tried.

The fifteen-spined Stickleback, _Gasterosteus spinachia_, does well, and
is very cheerful and brisk in his movements. Three or four would be an
improvement to any tank.

Young of the gray Mullet, too, do well; for if the supply of oxygen be
rather inadequate, they are observed to put their heads partly above the
surface of the water, and obtain an artificial supply in that
surreptitious manner. The black Goby, _Gobius niger_, has also been
tried with success; but his voracious character—devouring without
scruple even his own congeners—renders him on the whole not a very
desirable tenant; and yet it is a fine sight to see the little warrior
turn black when he seizes his prey, his turquois-coloured eyes dilating
with fury.

Several other kinds are mentioned, in a previous page, in the list of
animals placed by Mr. Gosse in his first experimental Aquarium.

The Pogge, _Aspidophorus cataphractus_, is a singularly formed fish that
might be added by way of experiment. The plate-armour in which his body
is clothed runs in regular longitudinal lines, showing eight sharp
ridges, running from head to tail, that have a singular and unfish-like
appearance. In confinement, however, he does not display himself to
advantage, generally lying near the bottom of the Aquarium.

The beautiful crimson maculations of the Ancient Wrasse, _Labrus
maculatus_, render him a very desirable tenant; but his size—small
specimens being eight or nine inches long—causes him to be inconvenient;
and, moreover, he is difficult to manage, and would probably require
altogether a special treatment. One of the smaller Wrasses, however,
_Crenilabrus cornubicus_, is a desirable guest; his minute size, and
varying and often gay colours, rendering him very attractive. He is an
active and eager searcher for food, but never takes any loosely floating
object, only darting at and detaching such atoms as are attached to the
different species of Algæ.

The Pipe-Fish, _Syngnathus acus_, is interesting in the tank, and also
the two-spotted sucker, _Lepidogaster bimaculatus_, a prettily coloured
and curious little fish, which has the faculty of attaching itself to
the side of the tank, or any other hard flat surface, by means of two
singularly-formed ventral fins, which act like the leather suckers by
means of which boys enjoy the sport of lifting heavy stones at the end
of a string. The spawn of this fish is like tiny amber beads, and is
attached to shells and other substances.

Among the Crustacea fitted for an Aquarium, the common Prawn, _Palæmon
serratus_, holds the first rank. In the first place, his cleansing
properties, in devouring all decaying animal matter, are most important.
But not less interesting are his graceful movements: Now, he steals
stealthily over the pebbles or the fronds of the Algæ, with his long,
slender, hair-like horns in gentle motion, with all the seeming wariness
of a cat (the resemblance being increased by candle-light by the fiery
glare of the eye); next, leaving his walking apparatus, or legs,
inactive, he uses only the swimming members, which are larger and
flatter, and bordered with a compact fringe; agitating these instruments
with beautiful regularity, he rises in the water with graceful ease (see
Plate VI.), his semi-transparent body, as he rises, giving to his
appearance a strange and somewhat apparition-like aspect, which has
caused him to be compared to a marine spectre.

The Prawn takes its food with its _second_ feet, two-fingered hands or
claws, and carries it to its mouth. The hands of the _first_ pair of
legs are only rudimental in appearance, but are precisely fitted to
their special purpose. They are his cleansing apparatus; and it is most
interesting to watch the operations of his toilet when he uses these
fringes as brushes, with which he cleanses his whole person most
thoroughly, being almost unmerciful in the amount of severe scrubbing to
which he subjects himself.

An allied species, _P. squilla_, is scarcely distinguishable from _P.
serratus_; but the handsome scarlet-striped Prawn, _Pardulus
annuticornis_, about the size of a Shrimp, is quite distinct, and would
make a valuable addition to the collection. The Lobster Prawn, also,
_Athanas nilescens_, has likewise been tried.

Some kinds of Crabs may be admitted, but not many; for several are
extremely voracious, and would soon clear off all the naked Zoöphytes
and most of the Molluscs.

The Climbing Crab, _Eurynome aspera_, is interesting in a tank from his
habits. His climbing is as graceful and skilful as that of a monkey, and
when he has succeeded in perching himself upon the highest object in the
tank, he forms a picturesque object.

Crabs, like Prawns, are sea-scavengers, and the kinds that do not attack
living creatures as well as dead are consequently useful in a tank. The
great Fiddler Crab, _Portunus puber_, is remarkably handsome. He is
clothed, in part, with a velvety brown fur, and the bare places of his
shell are of a shining black. His eyes are marked with scarlet, and
there are a few touches of bright blue about the head. If introduced,
his proceedings should be carefully watched.

There should certainly be a specimen of the Hermit Crab in a
Whelk-shell; and the Cleanser Crab, _Portunus depurator_, has been
tried, but these active and greedy Sea-Spiders must be closely looked
after.

It remains to speak of the Star-Fish tribe, which affords some of the
most beautiful and easily managed subjects for the Aquarium.

In the centre of the lower part of Plate VI. are a large and a small
specimen of the beautiful scarlet species, _Geniaster equestres_; just
above, to the right, the graceful pink _Cribella oculata_; further to
the right, _Asteria gibbosa_; and immediately above the _Cribella_, the
thin, leathery species, the bird’s foot Sea-Star, _Palmipes
membranaceus_. All these species are small, easily managed, and
especially suited to the Aquarium; as is also the finely-marked and
long-rayed _Ophicoma rosula_, his deep scarlet, with bright black marks,
and his slender limbs or rays, rendering him a conspicuous object. These
Star-Fish glide round the Aquarium, by the aid of their thousand
sucker-like feet, in a very interesting manner.

All the true Star-Fishes, the _Asteriæ_, have the body divided into
rays, like a star, and are furnished with sucking feet, or _cirrhi_,
which are tubular, and filled with water. The internal structure of
these creatures is very intricate and beautiful, and the skeleton of
almost any kind offers the appearance of that of some exquisitely
symmetrical flower. There are fourteen British species of Star-Fish, the
finest being the Sun-Star, _Solaster papposa_, the disk, surrounded with
twelve or thirteen rays, varying in colour from scarlet to deep purple,
the rays being sometimes of a different colour.

The _Luidia fragilissima_ is also a large kind, sometimes two feet
across, which is peculiar to the British shores. It possesses the
peculiar faculty of breaking itself into fragments when enraged or
captured; and, in a work by the lamented Professor Forbes, there is a
very graphic and facetious account of a specimen that escaped him in a
very determined way by a suicide of this kind.

 [Illustration: PLATE VI.

 1. Edwardsia vestita.
 2 & 3. Geniaster equestres.
 4. Cribella oculata.
 5. Asterina gibbosa.
 6. Palmipes membranaceus.
 7. Palæmon serratus.]

Stars of this class, having the power to dislocate their structure, are
popularly known as brittle Stars. Some affect to consider this faculty
not so very wonderful; but let such suppose for a moment some higher
animal—a man, for instance—gifted with a capacity for exploding his
trunk and limbs into moderately-sized fragments—into joints, as a
butcher would say—at any slight provocation, and then the character of
such a power would appear very sufficiently extraordinary. It is
possible that the fragments of the disruptured Star-Fish have the power,
in each separate fragment, of renewing the absent portions, and that
each portion thus becomes a perfect fish, the dissevered portions having
been noticed to retain their vitality long after their separation. We
know that the little Garden Lizard has the power of dislocating his tail
without effort, and leaving it between the thumb and finger, when he is
playfully caught by that appendage; and, also, that he has the power of
renewing his caudal extremity within a very short period. It is thought,
therefore, not impossible, reasoning by analogy, that the Star-Fish may
possess powers of a similar kind, of a somewhat more extensive
character.

The Amnion Star-Fish, called sometimes Five-fingered (_Asterias
rubens_), belongs to the division _Echinodermata_, that is, skinned like
the Hedgehog.

The Sea-Egg, Sea-Urchin, or Egg-Urchin, as it is sometimes called,
belongs also to the _Echinodermata_, or Hedgehog-skinned class, and form
interesting objects in the Aquarium; the flat species exhibiting much
more evidently their close affinity to the Star-Fish tribe, than those
of the more common spherical form.

To revert to other classes that occur to me as suitable objects for an
Aquarium, I may mention the “Red-noses,” as they are graphically termed
(_Saxicava rugosa_), a colony of which, peeping out of their holes in
the rock, would form a very striking object; and if a piece of their
native rock could be detached sufficiently deep not to disturb them in
the recesses of their tube-like burrows, their removal “_en bloque_”
would not be difficult. When touched, the Red-nose squirts a stream of
water at you in defiance, and darts back into his cavern. He is a small
bivalve, having his inner or immediate home within two rough brown
shells. The double-tubed proboscis with which he is furnished is
extended, when in search of food, to the mouth of his cave, in which
position the appearance of its ruddy terminus has given to this tribe
the characteristic name of “Red-noses.” How he contrives to bore a hole
in the solid rock, with any of the soft pulpy members with which he is
furnished, appears a mystery. Other Conchifers have, however, similar
capabilities, their ingenuity not being confined to rocks, and their
industry not being always harmless. Such, for instance, is that of the
Teredo, or Ship-worm, a species of which has long proved so inimical to
the formation of a Russian fleet in the Black Sea—the late war having,
however, proved a far more serious impediment to the development of that
portion of the Russian navy.

The Sea-Leaf, formed of twenty thousand or more cradles for young
Polypes, is also a curious object. It is the Polyzoön, sometimes called
the Hornwrack.

A few of the translucent Medusæ, in a young stage of their existence,
might be procured and tried, though their transport would be difficult;
and a group of creatures, of the genus _Zoöthamnium_, forming, as they
do, an object like a little tree of glass, covered with trumpet-shaped
bells, of the same crystalline aspect, each exhibiting its rotating
circle of minute cilia in rapid motion within, would form a singular and
beautiful complement to the wonders of the Aquarium, if its removal from
its native depths, and its location in its new home, could be
successfully managed.

[Illustration]

------------------------------------------------------------------------




                              CHAPTER IX.

                              CONCLUSION.


In conclusion, a few general remarks may be made, the observance of
which will usually ensure success in the formation of an Aquarium. In
the first place, if the vessel in which the Aquarium is to be
established be home-made, care must be taken not to use any cement that
has a disagreeable smell—which would be very soon fatal to creatures
accustomed to the pure waters of the ocean. Scott’s cement is said to be
better than putty, for fixing in the glass to the columns at the angles.

If cement be used to fix the rock-work of the miniature marine
landscape, let it be the best Portland cement, which, when dry, must be
soaked by filling the vessel with water, and the water changed several
times before the tank will be fit for use.

The best sand for the artificial beach, or bottom, is the Thames’ sand,
used by builders; but this must be washed several times, till the water
runs off quite clear, before it is fit for use—any other kind of sand,
if that cannot be procured, must be submitted to similar washings.
Sea-water can be procured by furnishing the steward or captain of any
Thames steamer, or the guard of a railway in connection with the coast,
with a clean barrel; the charge, in either case, for carriage and
trouble, would not exceed two or three shillings.

The artificial salt water has been found sufficient for Zoöphytes, but
not for fish and other of the higher class of marine animals, except for
a certain given time.

The composition for artificial sea-water is as follows:—

            Common salt                  3-1/2 oz.
            Epsom salts                    1/4 oz.
            Chloride of magnesium          200 grs. } troy.
            Chloride of potassium           40 grs. }

To these are added four quarts of water, and when the salts are
thoroughly dissolved, say on the following day, the liquid must be
filtered through a sponge; it is then fit for use.

Care must be taken to observe whether, when the sun shines and the light
is bright, the silvery bubbles of oxygen form upon the fronds of the
marine vegetation; and if not, it is certain that the marine plants are
not in a healthy state, and must be renewed.

Mr. Gosse gives the following final directions as to the class of
animals and plants that should be selected in preference for the
experiments of beginners.

With regard to sea-weed, he observes, do not take Oar-weeds or Tangle;
all the Fuci are of a slimy nature, which it is difficult to manage, and
as their size is inconvenient, and they have but little beauty, their
absence is not to be regretted.

Of animals, he says, take:—_Of Fish_—Blennies, Gobies, Wrasses. _Of
Mollusca_—Aplysia, Periwinkle, Chitons, Scallops, and Burrowing
Bivalves, such as Venus, Pullastra, &c. _Of Crustacea_—Eurynome,
Portunus puber, Carcinus mænas, Ebalia, Corystes, the Paguri, Porcellana
platycheles, and the Crangones, the Palæmones, that is, Shrimps and
Prawns. _Of Annelids_—Pectenaria, the Sabellæ, and the Serpulæ. _Of
Zoöphytes_—the Madrepores, and _all_ the Actiniæ.

Few will establish an Aquarium without deriving great mental
improvement, and the enlargement of their circle of acquirement, in a
direction highly calculated to develop some of the best and highest
feelings of our nature. Even the scientific cannot fail greatly to
enlarge their sphere of knowledge in this new, and almost untrodden,
field of research. The entomologist, sighing that there are no new Tiniæ
to add to his already enormous list, no new Curculios with which to form
another volume to the already portly series—these and other
physiological Alexanders, weeping for new regions to subdue, may hail
the Aquarium as a fertile source of further conquests; for,
notwithstanding the numerous and curious discoveries of recent
investigators, the depths of the ocean are as yet, comparatively
speaking, one of the untrodden fields of science; and a glorious arena
it presents—the Aquarium being one of the fairest channels for the
detection of its myriads of yet hidden mysteries.

The marine Aquarium is, as yet, a plaything, a mere toy; but it is
destined to become a far more important means of advancing science, and
ministering to popular instruction, amusement, and wonder, than is yet
dreamt of. It has yet to do for the ocean that which our menageries and
vast gardens, devoted to the service of natural history, have done for
the forests and mountains of the terrestrial portion of our planet.

We shall yet have tropical Aquaria, in which the temperature and
qualities of the sea between the tropics will be so successfully
imitated, that the glorious shells of those regions will be exhibited in
living motion to our greedily-curious gaze; and fish gleaming with
unusual dyes—metallic azure, and silvery crimson—will dart and glide in
our tropic-tempered tanks, as in their own tropic ocean, for our delight
and gratification. We are now entitled to expect from science, that it
shall exhibit to us the wonders of the tropic deeps, as it has shown us
the glorious plumage and velvet-spotted furs of the denizens of its
terrestrial forests.

This is, in fact, the only thing that remains for us to do, in making a
fitting popular display of the wonders of Nature, in order that we may
surpass the doings of the ancients in that field of popular instruction
and gratification.

Even in the days of Cyrus, we learn from the graphic Xenophon and other
sources, that every eastern satrap had his “paradises,” in which the
most curious animals of distant regions were preserved in a state of
liberty, and in a manner suited to their natures, either for the sport
of hunting or for the curious gratification of the eye.

The Romans, long before they had attained to the material wealth of the
modern nations of Europe, had exhibited to the people of their capital
all the noblest animals of Asia and Africa. Even the Giraffe and the
Hippopotamus were familiar forms to the Roman populace; while, with the
great modern nations of the west, the sight of these wonderful creatures
is but quite a recent gratification. It only remained to the ancients to
have exhibited a Titanic Aquarium, to render our triumph over their
labours in the field of popular natural history impossible. Had but a
Roman Warrington or Gosse developed the germ of such an idea, and an
Osler existed to furnish the glass—the Pompey, or Cæsar, or Crassus,
would not have been wanting to feast the eyes, both of patrician and
plebeian Rome, with an Aquarium measuring hundreds of feet in length, in
which the monsters of the deep would have been exhibited in deadly
conflict, and human divers, armed with net and trident, like the
retiariæ of their gladiatorial combats, would have encountered, beneath
the waters, the Shark, the Whale, or the Torpedo, to the shouts of
crowded circuses, the centre of which would have been a glass-walled
ocean.

But a gigantic Aquarium is, fortunately, a feat that yet remains for
modern science to achieve, and which it will doubtless accomplish. The
day will arrive when we shall see the living Behemoth—the Titan of the
deep—rolling majestic in waves of his native element, perhaps pursued by
his cruel enemy the Sword-Fish, or harried by a shoal of Herrings,
graphically exemplifying to a London crowd the origin of Yarmouth
bloaters. Or we may see the dreaded Shark float round and round the vast
glass prison seeking his prey, and the Shark-hunter of the south seas
may be imported to exhibit his skill in a bloodless conflict—mocking the
attempts of the sea monster to seize him, as the Spanish matador plays
long with the infuriated bull; but without necessitating the same
catastrophe to the animal, defenceless against the specially-trained
skill of his human antagonist. We have already had our crystal palaces,
covering their acres, and filled with objects of art and wealth from
every quarter of the globe; it is not impossible, therefore, that we may
have crystal-walled seas, in which aquatic menageries will form the last
new object of fashion and wonder.

For the present, however, the Aquarium is, as I have said, but a toy,
yet one full of pleasant instruction; and it doubtless contains the
germs of a development, the precise direction of which it is at present
difficult to guess.


                                THE END.


 London: THOMAS HARRILD, Printer, Salisbury Square, and Silver Street.

------------------------------------------------------------------------

                          Transcriber’s note:

Plate caption numbering discrepancies have been retained to match the
Plate.

List of Plates, ‘pink’ changed to ‘Pink,’ “The Pink Ceramium    47”

Page 16, ‘georgeous’ changed to ‘gorgeous,’ “and the gorgeous colours”

Facing page 34 (Plate XII), full stop struck following ‘Plate,’ “Plate
XII.”

Page 41, comma inserted after ‘βρυον,’ “Bryon (βρυον), a moss”

Facing page 48 (Plate III), full stop inserted after ‘multifida,’
“Nemaleon multifida.”

Page 59, ‘Zpoöhytology’ changed to ‘Zoöphytology,’ “known as
Zoöphytology.”

Page 83, ‘aquainted’ changed to ‘acquainted,’ “all are acquainted with”

Page 89, second ‘the’ struck, “spines of the same”

Page 98, ‘his’ changed to ‘is,’ “he is difficult to”

Page 108, ‘Zoophytes’ changed to ‘Zoöphytes,’ “Of Zoöphytes—the
Madrepores”