ink. These animals also escape detection by a very
extraordinary, chameleon-like power of changing their colour.
They appear to vary their tints according to the nature
of the ground over which they pass: when in deep water,
their general shade was brownish purple, but when placed on
the land, or in shallow water, this dark tint changed into one
of a yellowish green. The colour, examined more carefully,
was a French grey, with numerous minute spots of bright
yellow: the former of these varied in intensity; the latter
entirely disappeared and appeared again by turns. These
changes were effected in such a manner, that clouds, varying
in tint between a hyacinth red and a chestnut-brown, [4] were
continually passing over the body. Any part, being subjected
to a slight shock of galvanism, became almost black: a similar
effect, but in a less degree, was produced by scratching
the skin with a needle. These clouds, or blushes as they may
be called, are said to be produced by the alternate expansion
and contraction of minute vesicles containing variously
coloured fluids. [5]

This cuttle-fish displayed its chameleon-like power both
during the act of swimming and whilst remaining stationary
at the bottom. I was much amused by the various arts to
escape detection used by one individual, which seemed fully
aware that I was watching it. Remaining for a time motionless,
it would then stealthily advance an inch or two, like a
cat after a mouse; sometimes changing its colour: it thus
proceeded, till having gained a deeper part, it darted away,
leaving a dusky train of ink to hide the hole into which it
had crawled.