fresh water, to find it quickly dyed to a rich amber colour while
acquiring quite remarkable pungency. Even after the third change the
water was impregnated.

Interest in the mollusc became secondary upon the discovery of the host
and in consideration of the part it plays in the production of one of the
special effects of coral reefs; but the mollusc serves another and
timely purpose--purely personal and yet not to be disregarded. It
indicates a dilemma with which the wilful amateur in the first-hand study
of conchology is confronted. Although, as I have said, no local knowledge
of identity was available, reference to a well-disposed expert secured
the information that its title in science is VULSELLA LINGULATA; that
some twenty species are known; that they all associate with sponges, and
that possibly different species inhabit different kinds of sponges. It
may seem unpardonably gratuitous on the part of one professedly ignorant
to offer general observations upon natural phenomena; but as I find
myself among the great majority who do not know and who may be more or
less interested and anxious to learn, I claim justification in describing
that which to me is novel and rare. In this splendid isolation I cannot
hope to illuminate primary investigations with the searching light in
which science basks unblinkingly, for the nearest library of text-books
is close on a thousand miles away. Nor can I keep all my observations to
myself. There are some which, like murder, "will out," conscious though I
am of meriting the censure of the learned.

With this off my mind, let me return to the tenement sponges, which may
be likened to so many independent and flourishing manufactories of ozone.
Apart from the odour of brine common to every ocean and the scents of the
algae and some of the flowering plants of the sea, which are similar all
over the world, a coral reef has a strong and specific effluence. The