above two hundred species having been discovered. Many of them are very
beautiful both in shape and colour, so that they are highly valued by
collectors; they are principally found in the southern and tropical
seas, upon sandy bottoms, at depths varying from a few feet to seventeen
fathoms. The shells are generally thick and solid, rolled up, as it were,
into a conical form; the most familiar illustration that can be given of
this form is a sugar-loaf, which all these shells more or less resemble
in general outline, as thus—
[Illustration]
Cones are either plain or coronated, that is, crowned, having rows of
projections round the top of the shell, like the second of the above
figures; and this forms a mark of division into two classes, although
these classes often run, as it were, one into the other; some plain cones
having slight irregularities of surface, and some crowned ones being very
nearly plain.
The Common, or Ordinary Cone, (_Conus generalis_,) Plate V. Fig. 1, is an
elegantly-shaped and beautifully-marked shell, having much the appearance
of being carved out of some rare kind of marble. The Lettered Cone,
(_Conus littoralis_,) Fig. 2, appears to be scribbled over with Hebrew,
Greek, or Arabic characters, and almost every species has something
peculiar in its markings; clouds and veins, and dots, and stripes, and
bands, of every conceivable shape and mode of arrangement, may be met
with in these shells, whose surface, when the epidermis, or outer skin
is removed, bears a beautiful polish. Curious names have been given to
some of them, such, for instance, as the High Admiral, Vice Admiral, and
Guinea Admiral, which indicate the rank they hold in the estimation of
collectors. From five to twenty guineas is the price at which good and
rare ones have been valued, and one, the _Conus cedo nulli_, which may
be translated, the Cone second to none, has fetched the enormous sum of
three hundred guineas. It must not be supposed that these shells exhibit
all their beauties when, inhabited by a carnivorous, or flesh-eating
mollusk, they move slowly about, or lie for a time motionless among
the rocks and sand-beds of the ocean. The before-mentioned epidermis,
which is the Latin for the outer skin of the human body, covers them
like a cloak or mantle, which is the name it bears among naturalists.
Much careful labour is required to bring them to a fit state for cabinet
shells.
VOLUTES form an extensive family of shells under the name _Volutinæ_. The
greater part are natives of tropical seas, and dwell far down so that
they are seldom found on the coast, except after storms. There are a few
European species, but these are not remarkable for beauty, as most of
the others are. The generic name signifies twisted, or rather wreathed,
as flowers or leaves might be, about some central object. In these
shells the spire is generally short, as it is in many cones, sometimes
scarcely apparent; the form is usually elegant, and the markings often
striking and handsome. On Plate V, will be found three examples—Fig. 3
is the Undulated Volute, (_V. undulata_,) the Latin for a little wave
is _undula_, and these marks are like the lines caused by the flowing
of the waves on a sandy shore: this shell is found chiefly in the South
Pacific; the animal which inhabits it is prettily-marked with zebra-like
stripes. Fig. 4 is called the Pacific Volute, (_V. Pacificus_;) the
shape, it will be seen, is somewhat different, being more angular, and it
is without the waved lines. Fig. 5, the Bat Volute, (_V. vespertilio_,)
is more decidedly knobbed or spiked, approaching nearly to the shape of
some of the coronated ones. This species is found in the Indian seas; the
specific name is the Latin for a bat.
MITRES; these are usually considered as a genus, or branch of the
Volute family; the scientific name is _mitra_, the form is generally
long, slender, and pointed—something like the bishop’s mitre, hence the
common name of the genus. In the Episcopal Mitre, (_M. episcopalis_,)
Plate VI, Fig. 1, we see this form in its greatest perfection; this is a
handsome shell found in the Indian seas, and on the coasts of the South
Sea Islands. The mollusk is remarkable for a long proboscis, double the
length of the shell, the extremity of which swells into a club form, and
has an oval orifice or opening: the specific name _episcopalis_, comes
from the Latin, and means of, or like a bishop. The Tanned Mitre, (_M.
adusta_,) from the Latin _adustus_—burned or parched, is, what is called
fusiform and turretted, that is, shaped like a spindle, and having a
spire or turret-like termination. The streaks of colour are transverse,
that is, running the length of the shell, or in other words, they are
longitudinal; this, too, comes from the South Sea Islands. Fig. 2 is the
Wrinkled Mitre, (_M. corrugata_,) from the Latin _corrugo_—to wrinkle; it
is very different both in shape and markings, from the last species; the
whorls, it will be seen, are angulated or pointed above, and the lower
part of the shell is much larger than the spiral or upper portion. It is
a true mitre nevertheless, although not just such a one as a bishop would
like to wear. It inhabits the Indian Ocean, the coast of New Guinea, etc.
OLIVES; these, for richness of colour and brilliancy of effect, will
bear comparison with any genus of shells. Naturalists speak of them
collectively as _Olivinæ_; they belong to the Volute family, and are said
to number about eighty species. Most of those which have reached this
country, have come from the Mauritius, where they catch them with lines
baited with portions of Cuttle-fish. We have here depicted two of them,
namely, the Figured Olive, Fig. 3, (_Oliva textilina_,) from the Latin
_textilus_, which is woven or plaited; and the Ruddy Olive, Fig. 4, (_O.
sanguinolenta_,) from _sanguis_—blood.
We must now bring our notice of the Univalves to a conclusion; there are
several genera, and many very curious and beautiful species which we have
been unable to notice at all, and of those which we have, a short account
only could be given; sufficient however, as we trust, to interest our
readers in the subject, and induce them to continue the study of it into
larger works. Before leaving this division of shells, we would call their
attention to one of its greatest ornaments, that is the Ventricose Harp
Shell, (_Harpa ventricosa_,) from the Latin _ventriculus_—the stomach,
applied to this shell on account of its swelled or inflated shape.
Nothing, however, can be more elegant than the whole form, nor more
beautiful than the markings of this lovely species, (see Plate VI, Fig.
5,) which belongs properly to the Whelk family.
COWRIES.
Of Cowries we have already spoken in our chapter on the Uses of Shells,
they are among the commonest of our testaceous ornaments, and are
remarkable, especially the foreign kinds, for richness and diversity of
colour, and the high polish which they bear. The native species are small
plain shells, commonly called Pigs, from some real or fancied resemblance
which they bear to the swine; they are pretty little white-ribbed shells,
and are tolerably plentiful on various parts of the British coasts. There
are three kinds, namely, the Louse Pig, or Nun Cowry, the Flesh-coloured,
and European Pig Cowries. The first of these is of a pale reddish colour,
with six square black spots on the back; the second is a beautiful rose
tint; and the third is ash-coloured or pinkish, with three black dots,
and a white streak down the back. The Money Cowry, (_Cypræa moneta_,)
used as current coin in many parts of India, as well as on the coast of
Guinea, is a yellow and white shell, with a single band of the former
colour; it is small of size, and is sometimes called the Trussed Chicken,
for the same reason as the term Pigs is applied to its British relatives.
These Cowries are obtained principally about the Phillippine Islands,
the Maldive Islands, and the coast of Congo, where, after high tides,
the women collect them in baskets mixed with sand, from which they are
afterwards separated and cleaned, when they are ready for the market.
They are only useful as coin so long as they remain unbroken. The value
of a single shell is very small, as the following table will shew:—Four
Cowries make one gunder; twenty Gunders one punn; four Punns one anna;
four Annas one cahaun; and four Cahauns one rupee. The value of the
latter coin is equal to two shillings and threepence, English money,
and this would be exchangeable for five thousand one hundred and twenty
Cowries; so that it would never do to pay large sums in this kind of
coin: a waggon would be required to convey a few pounds with. In this
country the Money Cowries are frequently used as markers or counters in
social games; they are generally white, in shape rather broad and flat,
being much spread out round the edges, which are slightly puckered, like
frills. Here are two figures of the shell, exhibiting the back and front
view.
[Illustration]
On Plate VII, will be found a group of other Foreign Cowries, most
of which will be recognized as familiar ornaments of the mantel and
side-board. Fig. 1 is the Spotted or Leopard Cowry, sometimes also
called the Tiger Cowry, (_C. tigris_,) which, in the earlier stages of
its growth, is simply marked with broad bands of lighter colour across
the shell. Fig. 2, the Map Cowry, (_C. mappa_,) curiously marked and
shaded, so as to resemble a coloured map; there are several varieties of
this beautiful shell, such as the rosy and dark variety from the Pearl
Islands, in the Indian Ocean; the Citron and Dwarf Rich-mouthed variety,
from the Mauritius. Fig. 3, the Mole Cowry, (_C. talpa_,) the last word
being the Latin for a mole, is of a more slender form than most other
species of the _Cypræidæ_ family, so called on account of their beauty,
_Cyprea_ being a name of Venus, the goddess of beauty. Any one who has
seen a mole, must be struck with the resemblance of its general outline
to this shell, of which there is a darker-coloured variety of somewhat
stouter form, called _exustus_—burned or scorched. Of the Poached-egg
Cowries there are several species, the most common is called by
naturalists _Ovulum ovum_, Fig. 4, from _ovum_—an egg; the back of this
shell is much elevated and rounded; it is smooth and white; the inside
is orange brown. Some of the Poached-egg group are of a more slender and
angular shape, as, for instance, that called the Gibbous, (_O. Gibbosa_;)
the moon when more than half-full, is called gibbous, that is rounded
unequally, as this shell.
[Illustration]
Few shells undergo greater changes, both of shape and colour, during
the process of growth, than the Cowries, which are called in France
Porcelaines, on account of their high polish and brilliant hues; a single
species in different stages of development, might well be, and often is,
taken for distinct shells. Much might be said about the Mollusks which
inhabit them, but our present subject has rather to do with their outer
covering than their internal structure. The most rare and valuable,
if not the most beautiful of these Cowries, is the _C. aurora_, or
_aurantium_, Morning-dawn, or Orange Cowry, a perfect specimen of which
has been sold for fifty guineas. There is a very curious shell called
the Common Weaver’s Shuttle, (_Oculum volva_,) generally included in the
_Cyprea_ family; of this a representation will be found on Plate VII,
Fig. 5. This is brought from China.
BIVALVES.
Acephalous Mollusks, with Bivalve Shells, is the name given by modern
naturalists to the class of animals of which we have now to speak; the
only one of these terms which will require explanation is the first; it
comes from the Greek, and means headless, so an Acephalan is a molluscous
animal without a head, as
THE OYSTER,
Which may be considered as the King of Bivalves; his palace, to be sure,
is somewhat rough and rugged outside, but within, its walls are smooth
and polished, lustrous and iridescent, and altogether beautiful; of a
nacrous or pearly appearance, now flushing into a rose tint, now fading
into pure white, and adorned sometimes with goodly pearls of price; truly
this monarch of the _Conchifers_ has a habitation worthy of a prince,
wherein he lives in right royal state. Our readers may smile perhaps at
the idea of the solitary Oyster doing this, down there on his mud bank
or rocky anchorage ground, shut up in his dirty-looking shells, and
holding, as it seems, commune with no one, not even his fellow mollusks;
how can he be said to live in royal state, or indeed any state at all,
except in a most weary, stale, flat, and unprofitable one? And this only
shews how erroneously those often judge who do so hastily, and from first
appearances.
If we take a peep through a microscope, under the direction of a
naturalist named Rymer Jones, we shall see that “the shell of an Oyster
is a world occupied by an innumerable quantity of animals, compared
to which the Oyster itself is a colossus. The liquid enclosed between
the shell of the Oyster contains a multitude of embryos, covered with
transparent scales, which swim with ease; a hundred and twenty of these
embryos, placed side by side, would make an inch in breadth. This liquid
contains besides, a great variety of animalculæ, five hundred times less
in size, which give out a phosphoric light. Yet these are not the only
inhabitants of this dwelling—there are also three distinct species of
worms.”
Let us see if there are any hard names here that want explaining before
we go any further. The first we stumble upon is _Colossus_, which comes
from the Latin, and means a great image or statue, like that which
ancient historians tell us once bestrode the entrance to the harbour of
Rhodes. _Embryo_ comes from the Greek, and means something small and
unfinished, that is to expand or grow into a more perfect form, as the
seed into a plant. _Animalculæ_, are minute or very small animals, such
as cannot be distinguished without the help of a microscope, hence they
are sometimes called microscopic animals; this word comes from the Latin
_animalis_, which means having life. _Phosphoric_ signifies luminous,
or giving out light. The Greek name of the morning star is _Phospha_.
In Latin, _Phosphorus_ is a term applied to a substance which chemists
extract from bones and other animal matter, and which, when exposed to
air, burns with a pale blue light, like that emitted by the glow-worm.
Many of the oceanic or sea animalculæ are exceedingly phosphorescent, so
that by night, the waves appear like billows of flame. Of this luminosity
of the ocean, as it is termed, we shall have to speak on another
occasion. We will now return to the Oyster, who, it will be seen, is by
no means so solitary in his bivalve palace as might be supposed. He has
his torch-bearers, and other attendants, quite a host of them, no doubt
magnificently dressed, if we could but see them to advantage, and well
instructed in the several duties which they have to perform. Oh yes,
certainly, as the Irish poet has said,
“Of all the Conchiferous shell-fish,
The Oyster _is_ surely the King;”
Shall we continue the quotation? and say
“Arrah Mick, call the people who sell fish,
And tell them a dozen to bring:
For it’s I that intend to demonstrate,
The creature’s phenomena strange,
Its functions to set every one straight,
And exhibit their structure and range.”
Scarcely will our limited space permit us to do this, but a few of the
most remarkable particulars about this common Acephalan, we feel called
upon to set before our readers.
First, then, it belongs to the class _Conchifera_; this is a word which
we must stop to examine a little; it seems to come from the Latin
_concha_, which means a shell-fish with two shells, in other words a
bivalve mollusk. Second, our Oyster belongs to the class _Pectinidæ_.
Now _pecten_ is the Latin for a comb, and this class includes those
bivalve shells whose edges are toothed, or, as it is said, _pectinated_;
in the scallop and the cockle shells this peculiarity is more observable
than in those of other members of the class, and these form the
typical, or so to speak, pattern genus, _pecten_. Thirdly, the Common
Oyster is a _Monomyarian Conchifer_. Ah! that’s something like a name
for the acephaloid monarch! Look at these two words, _mono-myarian_,
_di-myarian_, you know of course that mony-syllable means one syllable,
and dis-syllable means two. You sometimes hear of a person who leads
a _monotonous_ life, and you think perhaps of the Oyster shut up in
his shell all alone, _one_ by himself; this notion you now know to be
a false one; although it is true that he has but one abductor muscle,
and therefore belongs to the division of the _Pectinidæ_ family called
_Monomyaria_, while the Pearl Oyster has two, and therefore belongs to
that termed _Dimyaria_. If, as they say, there is reason in the roasting
of eggs, surely there must be in the names given to the classes and
divisions of shells. We hope to have succeeded in making the why and the
wherefore in this case somewhat plain;—_one_—_two_—and away we go out
of this maze of hard names. But what about the abductor muscle, above
spoken of? well, this must be explained; _abduce_, coming from the Latin
_abduco_, means to separate, to draw away, hence we have _abduction_.
During the life of an Oyster, the usual and natural state of the shell
is that of being kept open for a little distance, to allow the water
necessary for its nourishment and respiration to flow in and out; but
as a security against danger, it was necessary to furnish the animal
with the means of rapidly closing the shell, and retaining the valves
in a closed state. These actions being only occasional, yet requiring
considerable force, are effected by means of a muscular power, for which
purpose one or two, or sometimes more strong muscles are placed between
the valves, their fibres passing directly across from the inner surface
of one to that of the other, and firmly attached to both, and these are
called the abductor muscles, because their office is to draw or pull;
how strongly they do this those whose business it is to open Oysters can
best tell; if the animal within were not alive, the process would not be
a difficult one, as in that case the muscles would be relaxed, and the
shell would come open of itself, so that actually people who eat Oysters
directly they are opened, swallow them “all alive-O!”
If a pair of the shells from which the delicious morsel has been
extracted, be taken in the hand, it may be noticed that one is much
thinner, smoother, and flatter than the other; this is the side most
exposed to the action of the water; the rougher and rounder side is that
which is attached to the rock, or other substance to which the animal
forms an attachment, that is usually life-long. The two portions of the
shell are joined together by a hinge of curious workmanship, which is
formed of the inner layer of the shell, and strengthened by a ligament
which is wonderfully elastic; when the shell is drawn together by the
abductor muscles, the ligament is at full stretch, and as soon as they
relax at all, it contracts, and causes the shell to gape. This process is
repeated as often as may be necessary for the safety and sustenance of
the animal within, whose mouth is situated at the narrowest part of its
habitation, namely, near the joint of the hinge, which connects its upper
and under shell. The anatomical structure of the Oyster is more perfect
than would be supposed, from its apparently low state of organization;
it has a heart, liver, and intestinal canal, and a bag near the mouth,
which answers the purpose of a stomach. Its breathing organs are gills,
closely resembling those of most other fish; it has little vessels which
convey the bile from the stomach to the liver, and may perhaps be subject
to bilious attacks, as well as those who swallow this curious piece
of organization at a mouthful, without thinking at all of the goodly
structure they are demolishing. There is the tiny heart with its series
of blood-vessels, just as perfect as in the larger animals. There are
the nerves in the shape of minute feelers, which appear to be acutely
sensible not only of actual contact with foreign bodies, but also of
sounds and movements from without. A very nice sense of feeling appears
to reside in what is called the beard, in scientific language _bissus_;
this is a kind of double fringe to the two lobes of the mantle, or sac,
as it is called, which envelopes the body of the animal, and floats free
from the shell, except just at the part nearer the valve where it is
attached.
We have just spoken of the beard of the Oyster, and this reminds us of
a conundrum which may serve to amuse our readers, and enliven these dry
details a little. Why is an Oyster the most anomalous, that is strange,
contradictory, creature in existence? Do you give it up? Well then it is
because
“It wears a beard without any chin,
And leaves its bed to be tucked in.”
Again, by this allusion to the “tucking in” of Oysters, a phrase more
expressive than polite, we have recalled to memory the saying of a quaint
old author, that they are “ungodly, uncharitable, and unprofitable meat;
ungodly, because they are eaten without grace; uncharitable, because they
leave nothing but shells, and unprofitable because they must swim in
wine.” Not, generally, however, are they eaten in this luxurious manner,
a little pepper and vinegar is all they commonly get in the way of sauce,
and those who swallow them thus accompanied, seem to do so with infinite
relish. A very long chapter, if not a whole book, might be written about
the historical associations of Oysters, for which our country has been
famous, as far back as the time of the first Roman invasion; much, too,
might be said about the Oyster beds and fisheries, which give employment
to thousands of our industrious population, but all this has so little
to do with natural history, that we can find no excuse for dwelling upon
it here. It is quite within the range of our subject, however, to state
that the “spat” or “spawn” of the Oyster is cast about the beginning of
May: at first it resembles a drop of greenish tallow, but by the aid of
the microscope it may be seen to consist of a great number of minute
particles, each of which is an egg, and will by-and-by become a perfect
fish; these increase in size very rapidly, and after floating about for
a while, sink to the bottom, and become attached to rock or some other
substance, in which position, if not violently detached or removed, they
complete their growth, and live out the term of their natural life. Their
food is minute animalculæ, and microscopic vegetation, on the nature of
which their flavour greatly depends.
They have many enemies besides man; the whelk, and the crab, the
sea-star, or “five fingers,” and the large drum-fish, which swallows
them almost by the bushel, shells and all; these help to thin the
Oyster-beds, and make the dredger’s labours less remunerative than
they would otherwise be. Here is a picture of one as he stands in his
boat just about to throw his dredge into the sandy bottom, where he
knows the delicious testaceans do, or ought to, lie most thickly. The
dredge, which is a triangular iron frame with a net over the bottom,
will naturally sink, and when the line to which it is attached ceases
to run out, the dredger will put his boat in motion, and draw it thus
over the Oyster-bed, and then pull it up filled, it may be, with little
fat “Miltons,” or large “Colchesters,” or such other kind as the spot is
known to yield.
[Illustration]
The Latin for Oyster is _Ostrea_, and that is a name given to a genus
of the _Pectinidæ_ family, comprising beside the _O. edulis_, or Common
Oyster, many other species. _Edulis_ means eatable. Home naturalists
divide these Ostraceans into two groups, first with simple or undulated,
but not plaited valves; second, those which have the borders of their
valves distinctly plaited.