LIFE'S SIMPLEST CHILDREN. 21 
such impure water, under a powerful microscope you 
may see them darting along by thousands. But the 
whip does not only serve them as an oar, it also sends 
the food they meet with into a tiny opening, one of 
life's first attempts at a mouth. With a little jerk, 
when the creature is still or fixed to the bottom, the 
whip drives still smaller beings than the monad itself 
into its wide-opened cavity, and there they are digested 
in a little watery bubble, which may be clearly seen 
in its body. The Noctiluca or night-glow (2, Fig. 3) 
is much larger, being often as large as the head of 
a small pin, and just below the outer rim of its slimy 
bag the sparks of light are given out. It has been 
reckoned that there are as many as 30,000 Noc- 
tilucae in one cubic inch of phosphorescent water, 
and it is almost impossible to grasp the idea of the 
millions upon millions of these tiny forms which 
must be floating over a sea which is giving out a 
glow of liquid fire for miles and miles. And it is only 
because of this light that we realise that they are there. 
There are just as many other forms in the water on 
every side of us, while we dream nothing of this 
teeming life in the midst of which we live. 
We cannot stop here to speak of the tube-sucker ''' 
and all his relations, which have a mouth at the end 
of every tube ; nor of the beautiful little bell-flower^ 
which may be seen in any pond or in sea-water, with 
its hanging bells whirling the food in by their little 
fringe of hairs (a, Fig. 3) ; or shutting up with the 
food inside, and starting back by curling up their 
slender stem (b} ; or splitting in two (c) and sending 
off buds (d, cT), which swim away to form new colonies 
* Acineta. t Vorticella nebulifera. 
