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POPULAR SCIENCE REVIEW. 
of animal life. But, since it lias been indubitably shown by 
numberless examples, that motion also belongs to vegetable 
life as well as to the animal, it was transferred to the 
botanists — not, however, until after exhaustive and prolonged 
argument — the motion produced by the cilia and a certain 
movement of the cells (both hereafter to be described), being 
the only points it has in common with the animal kingdom. 
Thus, as before remarked, it has been made a “con- 
fervoid” of the family Volvocineas, the most striking feature 
of the group being that it consists of a family of green cells, 
having the power of motion by means of fine cilia, or hairs, 
and held together by a delicate and more or less spherical 
membrane. 
The Yolvox Grlobator is the largest species in the family, 
and is by no means rare, being found in open, clear ponds, 
where the water is free from sewage; and particularly in 
those ponds whose wateiris not exhausted during summer nor 
flooded during winter, though it is, doubtless, found in some- 
what transient pools. We are more likely to meet with it on 
the sunny margins, especially if we seek it during the earlier 
months. If, in such situations, we dip a wide-mouth phial 
into the water near the surface, and hold it up against the 
light, a little green ball may be observed slowly moving 
about, the nature of which is readily recognized by the assist- 
ance of a pocket-lens ; indeed, although pond water presents 
many green balls moving about which are not Yolvoces, still 
the experienced naked eye may, without difficulty, recognize 
them from their being less opaque. The best manner of 
securing Yolvox Grlobator is to pass a small muslin net 
through the water gently, and then to invert it into the water 
of the wide-mouthed bottle, when a slight shake will detach 
them ; this can be frequently repeated till a sufficient number 
are secured. To place them in the live box for observation, 
the best plan is to use the glass dipping-tube in the mode 
described in books on the use of the microscope. 
- Let us now proceed to the more minute description of this 
exquisite organism. It averages about the fiftieth of an inch 
in diameter ; but considerable variation occurs in size. It is a 
symmetrically-formed sphere (fig. 1), composed of perfectly 
colourless transparent membrane, with colourless watery 
contents, without any aperture ; resembling a very thin glass 
bubble filled with water. But it is studded all over at equal 
distances with small green spots (fig. 1, a a) in quantity 
varying from thirty, to ten times that number ; to which the 
whole body owes its green colour, resembling, under a low 
power of the microscope, a glass ball studded with emeralds. 
These green spots, seen in profile, are drop-shaped (fig. 2, 
