478 
POPULAR SCIENCE REVIEW. 
minent character is most fully developed, call them the family 
Melicertade. Like the Flower Animalcules, they live in 
tubular cases, which are formed by an exudation from the sur- 
face of their bodies, and which are moulded into shape by their 
movements on the foot as a pivot. In one or two instances, in- 
deed, the enveloping case seems wanting’; but, as we have seen in 
some of the Floscules, that this defence is occasionally evanes- 
cent, it may be that in these it is so slight as to have escaped de- 
tection. Their bodies are nearly cylindrical, abruptly attenuated 
to a long and slender foot, the base of which is, after early 
infancy, permanently attached to some fixed substance, such as 
the stem or leaves of water-plants. In one instance, however, 
the feet of many individuals are attached to each other, and 
thus a radiating’ sphere of animals is composed which swims at 
large. This I shall describe more particularly presently. 
Thus far, the Crown Wheel and the Floscules might have 
been united with this family ; but we now come to important 
differences whereby it is distinguished from those genera. We 
have seen that they have a disk which runs into five points, 
beset with long bristles, only occasionally vibratile. Our pre- 
sent subjects have disks which do not run into points, whose 
divisions are twofold and fourfold, and whose margins are 
uniformly clothed with short cilia, which vibrate without inter- 
mission (during expansion), with a succession of rhythmic waves 
whose appearance to the eye is that of an' endless rotation of 
toothed wheels. 
Then most important distinctive character, however, though 
not so obvious as the one just mentioned, since it requires 
high powers of the instrument and practised skill in the 
observer to make it manifest, is the form of that organ in the 
midst of the upper body, which has been generally called a 
gizzard, but which I have reasons for considering as the true 
mouth. To describe, so as to be intelligible, an organ so com- 
plex as this, is difficult, but with the aid of the following 
illustration I hope to give my readers some idea of it. Take a 
rather pointed apple and cut it through from the point to the 
base, leaving the short stalk attached to one half. Choose this 
half (rejecting the other), and again split it through the middle, 
doing it carefully, so as not to separate either from the stalk 
which just holds the pieces together. Pull the tips slightly 
apart and lay them down on then’ rounded surfaces, the flat 
sides uppermost. Now take six pins, and bending them all 
into an arch, lay three across each division of the semi-apple, 
so that they lie parallel, a little apart from each other, the 
points of one set just meeting the points of the other, if the two 
divisions be pressed together. If the pins could be slightly sunk 
into the face of the apple, it would be so much the better. The pins 
