glaucus-第10章
按键盘上方向键 ← 或 → 可快速上下翻页,按键盘上的 Enter 键可回到本书目录页,按键盘上方向键 ↑ 可回到本页顶部!
————未阅读完?加入书签已便下次继续阅读!
clearly。 The valves gape apart some three…quarters of an inch。
The semi…pellucid orange 〃mantle〃 fills the intermediate space。
Through that mantle; at the end from which the foot curves; the
siphons protrude; two thick short tubes joined side by side; their
lips fringed with pearly cirri; or fringes; and very beautiful they
are。 The larger is always open; taking in the water; which is at
once the animal's food and air; and which; flowing over the
delicate inner surface of the mantle; at once oxygenates its blood;
and fills its stomach with minute particles of decayed organized
matter。 The smaller is shut。 Wait a minute; and it will open
suddenly and discharge a jet of clear water; which has been robbed;
I suppose; of its oxygen and its organic matter。 But; I suppose;
your eyes will be rather attracted by that same scarlet and orange
foot; which is being drawn in and thrust out to a length of nearly
four inches; striking with its point against any opposing object;
and sending the whole shell backwards with a jerk。 The point; you
see; is sharp and tongue…like; only flattened; not horizontally;
like a tongue; but perpendicularly; so as to form; as it was
intended; a perfect sand…plough; by which the animal can move at
will; either above or below the surface of the sand。 (2)
But for colour and shape; to what shall we compare it? To polished
cornelian; says Mr。 Gosse。 I say; to one of the great red
capsicums which hang drying in every Covent…garden seedsman's
window。 Yet is either simile better than the guess of a certain
lady; who; entering a room wherein a couple of Cardium tuberculatum
were waltzing about a plate; exclaimed; 〃Oh dear! I always heard
that my pretty red coral came out of a fish; and here it is all
alive!〃
〃C。 tuberculatum;〃 says Mr。 Gosse (who described it from specimens
which I sent him in 1854); 〃is far the finest species。 The valves
are more globose and of a warmer colour; those that I have seen are
even more spinous。〃 Such may have been the case in those I sent:
but it has occurred to me now and then to dredge specimens of C。
aculeatum; which had escaped that rolling on the sand fatal in old
age to its delicate spines; and which equalled in colour; size; and
perfectness the noble one figured in poor dear old Dr。 Turton's
〃British Bivalves。〃 Besides; aculeatum is a far thinner and more
delicate shell。 And a third species; C。 echinatum; with curves
more graceful and continuous; is to be found now and then with the
two former。 In it; each point; instead of degenerating into a
knot; as in tuberculatum; or developing from delicate flat briar…
prickles into long straight thorns; as in aculeatum; is close…set
to its fellow; and curved at the point transversely to the shell;
the whole being thus horrid with hundreds of strong tenterhooks;
making his castle impregnable to the raveners of the deep。 For we
can hardly doubt that these prickles are meant as weapons of
defence; without which so savoury a morsel as the mollusc within
(cooked and eaten largely on some parts of our south coast) would
be a staple article of food for sea…beasts of prey。 And it is
noteworthy; first; that the defensive thorns which are permanent on
the two thinner species; aculeatum and echinatum; disappear
altogether on the thicker one; tuberculatum; as old age gives him a
solid and heavy globose shell; and next; that he too; while young
and tender; and liable therefore to be bored through by whelks and
such murderous univalves; does actually possess the same briar…
prickles; which his thinner cousins keep throughout life。
Nevertheless; prickles; in all three species; are; as far as we can
see; useless in Torbay; where no wolf…fish (Anarrhichas lupus) or
other owner of shell…crushing jaws wanders; terrible to lobster and
to cockle。 Originally intended; as we suppose; to face the strong…
toothed monsters of the Mediterranean; these foreigners have
wandered northward to shores where their armour is not now needed;
and yet centuries of idleness and security have not been able to
persuade them to lay it by。 This … if my explanation is the right
one … is but one more case among hundreds in which peculiarities;
useful doubtless to their original possessors; remain; though now
useless; in their descendants。 Just so does the tame ram inherit
the now superfluous horns of his primeval wild ancestors; though he
fights now … if he fights at all … not with his horns; but with his
forehead。
Enough of Cardium tuberculatum。 Now for the other animals of the
heap; and first; for those long white razors。 They; as well as the
grey scimitars; are Solens; Razor…fish (Solen siliqua and S。
ensis); burrowers in the sand by that foot which protrudes from one
end; nimble in escaping from the Torquay boys; whom you will see
boring for them with a long iron screw; on the sands at low tide。
They are very good to eat; these razor…fish; at least; for those
who so think them; and abound in millions upon all our sandy
shores。 (3)
Now for the tapering brown spires。 They are Turritellae; snail…
like animals (though the form of the shell is different); who crawl
and browse by thousands on the beds of Zostera; or grass wrack;
which you see thrown about on the beach; and which grows naturally
in two or three fathoms water。 Stay: here is one which is 〃more
than itself。〃 On its back is mounted a cluster of barnacles
(Balanus Porcatus); of the same family as those which stud the
tide…rocks in millions; scratching the legs of hapless bathers。 Of
them; I will speak presently; for I may have a still more curious
member of the family to show you。 But meanwhile; look at the mouth
of the shell; a long grey worm protrudes from it; which is not the
rightful inhabitant。 He is dead long since; and his place has been
occupied by one Sipunculus Bernhardi; a wight of low degree; who
connects 〃radiate〃 with annulate forms … in plain English; sea…
cucumbers (of which we shall see some soon) with sea…worms。 But
however low in the scale of comparative anatomy; he has wit enough
to take care of himself; mean ugly little worm as he seems。 For
finding the mouth of the Turritella too big for him; he has
plastered it up with sand and mud (Heaven alone knows how); just as
a wry…neck plasters up a hole in an apple…tree when she intends to
build therein; and has left only a round hole; out of which he can
poke his proboscis。 A curious thing is this proboscis; when seen
through the magnifier。 You perceive a ring of tentacles round the
mouth; for picking up I know not what; and you will perceive; too;
if you watch it; that when he draws it in; he turns mouth;
tentacles and all; inwards; and so down into his stomach; just as
if you were to turn the finger of a glove inward from the tip till
it passed into the hand; and so performs; every time he eats; the
clown's as yet ideal feat; of jumping down his own throat。 (4)
So much have we seen on one little shell。 But there is more to see
close to it。 Those yellow plants which I likened to squirrels'
tails and lobsters' horns; and what not; are zoophytes of different
kinds。 Here is Sertularia argentea (true squirrel's tail); here;
S。 filicula; as delicate as tangled threads of glass; here;
abietina; here; rosacea。 The lobsters' horns are Antennaria
antennina; and mingled with them are Plumulariae; always to be
distinguished from Sertulariae by polypes growing on one side of
the branch; and not on both。 Here is falcata; with its roots
twisted round a sea…weed。 Here is cristata; on the same weed; and
here is a piece of the beautiful myriophyllum; which has been
battered in its long journey out of the deep water about the ore
rock。 For all these you must consult Johnson's 〃Zoophytes;〃 and
for a dozen smaller species; which you would probably find tang