ery of the dead reef--if the
reef be dead--so that the eye is continually baffled and the collector
continually deceived. I have taken shells for stones and stones for
shells, the one as often as the other. A prevailing character of the
coral is to be dotted with small spots of red, and it is wonderful how
many varieties of shell have adopted the same fashion and donned the
disguise of the red spot. A shell I had found in plenty in the Marquesas
I found here also unchanged in all things else, but there were the red
spots. A lively little crab wore the same marking. The case of the
hermit or soldier crab was more conclusive, being the result of
conscious choice. This nasty little wrecker, scavenger, and squatter has
learned the value of a spotted house; so it be of the right colour he
will choose the smallest shard, tuck himself in a mere corner of a
broken whorl, and go about the world half naked; but I never found him
in this imperfect armour unless it was marked with the red spot.

Some two hundred yards distant is the beach of the lagoon. Collect the
shells from each, set them side by side, and you would suppose they came
from different hemispheres; the one so pale, the other so brilliant; the
one prevalently white, the other of a score of hues, and infected with
the scarlet spot like a disease. This seems the more strange, since the
hermit crabs pass and repass the island, and I have met them by the
Residency well, which is about central, journeying either way. Without
doubt many of the shells in the lagoon are dead. But why are they dead?
Without doubt the living shells have a very different background set for
imitation. But why are these so different? We are only on the threshold
of the mysteries.

Either beach, I have said, abounds with life. On the sea-side and in
certain atolls this profusion of vitality is even shocking: the rock
under foot is mined with it. I have broken oft--notably in Funafuti and
Arorai[5]--great lumps of ancient weathered rock that rang under my
blows like iron, and the fracture has been full of pendent worms as long
as my hand, as thick as a child's finger, of a slightly pinkish white,
and set as close as three or even four to the square inch. Even in the
lagoon, where certain shell-fish seem to sicken, others (it is
notorious) prosper exceedingly and make the riches of these islands.
Fish, too, abound; the lagoon is a closed fish-pond, such as might
rejoice the fancy of an abbot; shark