tails to the
stalks or leaves of those submerged forests. The omniscient schoolboy
must often have watched in aquariums the habits and manners of the
common sea-horses, twisted together by their long thin bodies into one
inextricable mass of living matwork, or anchored firmly with a treble
serpentine coil to some projecting branch of coralline or of quivering
sea-wrack. Bad swimmers by nature, utterly unarmed, and wholly
undefended by protective mail, the pipe-fish generally can neither fight
nor run away: and therefore they depend entirely for their lives upon
their peculiar skulking and lurking habits. Their one mode of defence is
not to show themselves; discretion is the better part of their valour;
they hide as much as possible among the thickest seaweed, and trust to
Providence to escape observation.

Now, with any animals thus constituted, cowards by hereditary
predilection, it must necessarily happen that the more brightly coloured
or obtrusive individuals will most readily be spotted and most
unceremoniously devoured by their sharp-sighted foes, the predatory
fishes. On the other hand, just in proportion as any particular
pipe-fish happens to display any chance resemblance in colour or
appearance to the special seaweed in whose folds it lurks, to that
extent will it be likely to escape detection, and to hand on its
peculiarities to its future descendants. A long-continued course of the
simple process thus roughly described must of necessity result at last
in the elimination of all the most conspicuous pipe-fish, and the
survival of all those unobtrusive and retiring individuals which in any
respect happen to resemble the fucus or coralline among which they
dwell. Hence, in many places, various kinds of pipe-fish exhibit an
extraordinary amount of imitative likeness to the sargasso or seaweed to
whose tags they cling; and in the three most highly developed Australian
species the likeness becomes so ridiculously close that it is with
difficulty one can persuade oneself one is really and truly looking at a
fish, and not at a piece of strangely animated and locomotive fucus.

Of course, the playful pipe-fish is by no means alone in his assumption
of so neat and effective a disguise. Protective resemblances of just the
same sort as that thus exhibited by this extraordinary little creature
are common throughout the whole range of nature; instances are to be
found in abundance, not only among beasts, birds, reptiles,