stretches forth those on the side towards which it would go, fixes
them by means of the sucker at the tip of each, and, simultaneously
withdrawing those in the rear, pulls itself along.

The mouth, placed in the centre of the base, is very large in
proportion to the size of the animal. It is formed of five shelly,
wedge-shaped pieces, each ending in a hard, triangular tooth. The
whole mouth is a conical box, called by naturalists "Aristotle's
lantern."

The shell is hardly thicker than that of a hen's egg, and is even more
fragile. When the spines are rubbed off, the brioche-like shape is
modified, and in place of the depression in the middle of the upper
side there is seen a slight prominence.

Mine was a very inoffensive creature. He occupied the same corner for
many weeks, and changed his place only when a different arrangement of
stones was made. He then wandered to a remote part of the tank and
chose a new abode. Both retreats were on the shady side of a stone
overhung with plants. There for months he quietly kept house, only
going up and down his hand-breadth of room once or twice a day.
Minding his own business without hurt to his neighbor, he dwelt in
unambitious tranquillity. Had he not fallen a victim to the most cruel
maltreatment, he might still adorn his humble station.

As he was sitting one evening at the door of his house, bending about
his lithe arms in the way he was wont, two itinerant Sticklebacks
chanced to pass that way. They paused, and, not seeing the necessity
for organs of which they had never known the use, they at once decided
on their removal.