of
animal enlarged. _m_, Mouth. _c_, Digestive cavity. _s_, Sac into
which the tentacles are withdrawn. _p_, Bands with comb-like plates.
3, Portion of a band enlarged to show the moving plates _p_.]

Let us take the Cydippe first (1, Fig. 9). I have six here, each in a
separate tumbler, and could have brought many more, for when I dipped
my net in the pool yesterday such numbers were caught in it that I
believe the retreating tide must just have left a shoal behind. Put a
tumbler on the desk in front of you, and if the light falls well upon
it you will see a transparent ball about the size of a large pea
marked with eight bright bands, which begin at the lower end of the
ball and reach nearly to the top, dividing the outside into sections
like the ribs of a melon. The creature is so perfectly transparent
that you can count all the eight bands.

At the top of the ball is a slight bulge which is the mouth (_m_ 2,
Fig. 9), and from it, inside the ball hangs a long bag or stomach,
which opens below into a cavity, from which two canals branch out, one
on each side, and these divide again into four canals which go one
into each of the tubes running down the bands. From this cavity the
food, which is digested in the stomach, is carried by the canals all
over the body. The smaller tubes which branch out of these canals
cannot be seen clearly without a very strong lens, and the only other
parts you can discern in this transparent ball are two long sacs on
each side of the lower end. These are the tentacle sacs, in which are
coiled up the tentacles, which we shall describe presently. Lastly you
can notice that the bands outside the globe are broader in the middle
than at the ends, and are striped across by a number of ridges.

In moving the tumblers the water has naturally been shaken, and the
creature being alarmed will probably at first remain motionless. But
very soon it will begin to play in the water, rising and falling, and
swimming gracefully from side to side. Now you will notice a curious
effect, for the bands will glitter and become tinged with prismatic
colors, till, as it moves more and more rapidly these colors,
reflected in the jelly, seem to tinge the whole ball with colors like
those on a soap-bubble, while from the two sacs below come forth two
long transparent threads like spun glass. At first these appear to be
simple threads, but as they gradually open out to about four or five
inches, smaller threads unc