oil on each side of the line till there are
about fifty on each line. These short tendrils are never still for
long; as the main threads wave to and fro, some of the shorter ones
coil up and hang like tiny beads, then these uncoil and others roll
up, so that these graceful floating lines are never two seconds alike.

We do not really know their use. Sometimes the creature anchors itself
by them, rising and falling as they stretch out or coil up; but more
often they float idly behind it in the water. At first you would
perhaps think that they served to drive the ball through the water,
but this is done by a special apparatus. The cross ridges which we
noticed on the bands are really flat comb-like plates (_p_, Fig. 9),
of which there are about twenty or thirty on each band; and these
vibrate very rapidly, so that two hundred or more paddles drive the
tiny ball through the water. This is the cause of the prismatic
colors; for iridescent tints are produced by the play of light upon
the glittering plates, as they incessantly change their angle.
Sometimes they move all at once, sometimes only a few at a time, and
it is evident the creature controls them at will.

This lovely fairy-like globe, with its long floating tentacles and
rainbow tints, was for a long time classed with the jelly-fish; but it
really is most nearly related to the sea-anemones, as it has a true
central cavity which acts as a stomach, and many other points in
common with the _Actinozoa_. We cannot help wondering, as the little
being glides hither and thither, whether it can see where it is going.
It has nerves of a low kind which start from a little dark spot (_ng_)
exactly at the south pole of the ball, and at that point a sense-organ
of some kind exists, but what impression the creature gains from it of
the world outside we cannot tell.

I am afraid you may think it dull to turn from such a beautiful being
as this, to the gray leaf which looks only like a dead dry seaweed;
yet you will be wrong, for a more wonderful history attaches to this
crumpled dead-looking leaf than to the lovely jelly-globe.

[Illustration: FIG. 10. THE SEA-MAT OR FLUSTRA (_Flustra foliacea_).

1, Natural size. 2, Much magnified, _s_, Slit caused by drawing in of
the animal _a_.]

First of all I will pass round pieces of the dry leaf (1, Fig. 10),
and while you are getting them I will tell you where I found the
living ones. Great masses of the Flustra, as it is called, line