bells
so tiny that whole branches of them look only like a fringe of hair,
jelly globes rising and falling in the water, patches of living jelly
clinging to the rocky sides of the pool, and a hundred other forms,
some so minute that you must examine the fine sand in which they lie
under a powerful microscope before you can even guess that they are
there.

[Illustration: FIG. 1. GROUP OF SEAWEEDS.

(Natural size.)

1, _Ulva Linza._ 2, _Sphacelaria filicina._ 3, _Polysiphonia
urceolata._ 4, _Corallina officinalis._]

So it has proved a rich hunting-ground, where summer and winter,
spring and autumn, I find some form to put under my magic glass. There
I can watch it for weeks growing and multiplying under my care; moved
only from the aquarium, where I keep it supplied with healthy
sea-water, to the tiny transparent trough in which I place it for a
few hours to see the changes it has undergone. I could tell you
endless tales of transformations in these tiny lives, but I want
to-day to show you a few of my friends, most of which I brought
yesterday fresh from the pool, and have prepared for you to examine.

[Illustration: FIG. 2. _Ulva lactuca_, A GREEN-SEAWEED, GREATLY
MAGNIFIED TO SHOW STRUCTURE. (_After Orested)._

s, Spores in the cells, _ss_, Spores swimming out. _h_, Holes through
which spores have escaped.]

Let us begin with seaweeds. I have said that there are three leading
colors in my pool--green, olive, and red--and these tints mark roughly
three kinds of weed, though they occur in an endless variety of
shapes. Here is a piece of the beautiful pale green seaweed, called
the Laver or Sea-Lettuce, _Ulva Linza_ (1, Fig. 1),[1] which grows in
long ribbons in a sunny nook in the water. I have placed under the
first microscope a piece of this weed which is just sending out young
seaweeds in the shape of tiny cells, with lashes very like those we
saw coming from the moss-flower, and I have pressed them in the
position in which they would naturally leave the plant. You will also
see on this side several cells in which these tiny spores are forming,
ready to burst out and swim; for this green weed is merely a
collection of cells, like the single-celled plants on land. Each cell
can work as a separate plant; it feeds, grows, and can send out its
own young spores.

[Footnote 1: The slice given in Fig. 2 is from a broader-leaved form,
_U. lactuca_, because this species, being composed of only one layer
of cells,