At the very first glance into this little rock-hollow, all fringed with
crimson and purple weed, lined with scales of lilac coralline, and
partly shadowed by the olive fronds of the leathery tangle, we discern
many forms of animal life. Here, for instance, is a fine handsome
shelled mollusk, the Purple-spotted Top.[1] Before we take him up, let
us notice for a moment with what an easy even movement he glides along
over the leaves of the sea-weed, now over the stony projections of the
pool, now on the broad weeds again. On lifting the shell, we find that
the fine, fleshy, apricot-coloured animal clings with considerable
force to the weed; and on transferring it to a glass bottle, we get a
better sight of the organ by which it maintains both its stability and
its movements. The under-surface of the creature, then, forms a long,
nearly parallel-sided sole, abruptly pointed behind, where it stretches
to a considerable distance in the rear of the shell, and bounded in
front by a slightly-thickened transverse rim, a little arched, and
projecting on each side. This organ is the foot, and it is composed of
muscular fibres elaborately interwoven, much as in the human tongue,
whereby great versatility and power of motion are communicated to it;
indeed, when in motion, it strongly reminds one of the human tongue.
[Illustration: