reinforced it with grains of sand when it realised that there was
something better than slush for a dwelling. The sandy coverlet is
evidence of the gift of discrimination.

A still more highly endowed relation spins a similar fabric, upon which
are loosely agglutinated numbers of small dead shells, grit, and even
opercula a quarter of an inch in diameter. In weight, size, and number of
its constituents this exterior armour is altogether disproportionate to
the extreme tenuity of its foundation. Too unsubstantial to sustain its
own weight, it sprawls, like the track of a tipsy snail, indeterminately,
slowly developing its sinuosities over the irregular surface of a rock,
and slightly adherent thereto, throughout its whole length. Of this there
seem to be several nicely shaded grades, some in the form of galleries
laboriously built of a mixture of mud and sand, and each indicating
superiority to the naked denizen of the clement mud. They seem to be
superior in appearances also, for some of the animals display brightly
coloured plume-like tentacles, long and capable of being ostentatiously
fluttered.

The individual worm next to be described typifies such a wonderful
advance that it might almost be designated a subsequent and intrusive
sport, no marked are the distinctions it exhibits. It is one of the
shell-binders (PECTINARIA), but its mansion of mosaics is unique and
beautiful. In the universal struggle for place, self-preservation, and
food, the animal has acquired a higher order of intelligence and keener
perceptions of safety and of the niceties of life than its fellows.
Living in sand and mud, in obedience to some gracious instinct, it
gathers numbers of small shells, grit, and fragments of coral wherewith
to construct a tube, somewhat similar in shape to the horn of cornucopia,
and from three to six inches long. The materials are cemented together in