amethyst wing shines in the same light with the same prismatic divisions.
But even in the London river, if you go and seek among the pebbles above
Hammersmith Bridge when the river is low, you may find a score of
_neretina_ shells not one of which is coloured like the rest or
ornamented with exactly the same pattern, yet each is fit to bejewel the
coronet of some Titania of the waters. A number of these tiny shells,
gathered from below the bridge, lie before the writer, set on black satin
to display the hues. They look at a little distance like a series of mixed
Venetian beads, but of more elegant form. From whichever side they are
seen, the curves are the perfection of flowing line. The colouring and
ornament of each is a marvel and delight. Some are black, with white spots
arranged in lines following the curves, and with the top of the blunt
spiral white. These "black-and-white marble" patterns are followed by a
whole series in which purple takes the place of black, and the spots are
modified into scales. Then comes a row of rose-coloured shells, some with
white lance-heads, or scales, others with alternate bands of white scales
and white dots. Some are polished, others dull, some rosy pink, others
almost crimson. Some are marked with cream and purple like the juice of
black currants with cream in it. In some the scale pattern changes to a
chequer, some are white with purple zig-zags. And lastly come a whole
series in pale olive, and olive and cream, in which the general colour is
that of a blackcap's egg, and the pattern made by alternate spots of olive
and bands of cream. If these little gems of beauty come out of the London
river, what may we not expect in the upper waters of the silver Thames?[1]
A search in the right places in its course will show. But these
_neretinae_ are everywhere up to the source of the river, for they
feed on all kinds of decaying substances. If the pearl is the result of a
disease or injury, the beauty of the _neretina_ is a product or
transformation from foul things to fair ones.