chance stragglers that
come their way. And of the _Pimelodus gulio_, a little, strongly-helmed
fish, with a naked body, I was informed by Mr. Duff, on the authority of
the gentleman who had presented the specimens to the Museum, that it
burrowed in the holes of muddy banks, from which it shot out its armed
head, and arrested, as they passed, the minute animals on which it
preyed. The animal world is full of such compensatory defences: there is
a half-suit of armor given to shield half the body, and a wise instinct
to protect the rest. The _Pholas crispata_ cannot shut its valves so as
to protect its anterior parts, without raising them from off those parts
which lie behind: like the Irishman in the haunted house, who attempted
lengthening his blanket by cutting strips from the top and sewing them
on to the bottom, it loses at the one end what it gains at the other;
but, hemmed round by the solid walls of the recess which it is its
nature to hollow out for itself in shale or stone, the anterior parts,
though uncovered by the shell, are not exposed. By closing its valves
anteriorly, it shuts the door of its little house, made like that of the
coney-folk of Scripture, in the rock; and then, of the entire cell in
which it dwells so secure, what is not shut door is impregnable wall.
The remark of Paley, that the "human animal is the only one which is
naked, and the only one which can clothe itself," is by no means quite
correct. One half the hermit crab is as naked as the "human animal," and
even less fitted for exposure; for it consists of a thin-skinned, soft,
unmuscular bag, filled with delicate viscera; but not even the human
animal is more skilful in clothing himself in the spoils of other
animals than the hermit crab in wrapping up its naked bag in the strong
shell of some dead fusus or buccinum, which it carries about with it in
all its peregrinations, as at once clothes, armor, and house. Nature
arms its front, and it is itself wise enough to arm its rear. Now, it
seems not improbable that the half-armed Coccosteus, a heavy fish,
indifferently furnished with fins, may have burrowed, like the recent
_Silurus glanis_ or _Pimelodus gulio_, in a thick mud,--of the existence
of which in vast quantity, during the times of the Old Red Sandstone,
the dark Caithness flagstones, the fetid breccia of Strathpeffer, and
the gray stratified clays of Cromarty, Moray, and Banff, unequivocally
testify; and that it may have thus not onl