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POPULAR SCIENCE REVIEW. 
tion of a ‘ rolling' sphere’). It was formerly known as the 
‘ globe animalcule ;’ ’tis, however, not an animalcule at all, but 
one of the lowest forms of vegetable life.” 
“ What ! ” she exclaimed ; “ a plant ? Why, it lives — it 
moves.” 
“ All plants live, in one sense, and many of the lowest possess 
the power of locomotion. There are some living forms to 
which naturalists have not yet been able to assign a definite 
position, either in the animal or vegetable kingdom ; but this 
one is now generally recognized as a true plant. So also your 
‘moon in her first quarter;’ it is Closterium moniliferum. I 
am sorry the name is not more homely ; but it means the moni- 
liferous, or necklace-shaped Closterium (from the fancied resem- 
blance between the row of globules within it, and a necklace). 
Another species of Closterium is called lunula, but it does 
not resemble the moon as much as this one. 
“ The object you called Jupiter, the smaller globe, is a young 
Y olvox in process of development — also a plant, therefore ; and 
its ‘ satellites ’ are the moving gei*ms of another lowly plant. 
Protococcus viridis, whose myriads of myriads impart to the 
surface of the rain-water in cisterns that green tinge which you 
must frequently have noticed. They subsequently lose their 
power of locomotion, and, settling down at the bottom of the 
vessel, they assume a reddish hue. 
“ The double cross, Staurastrum gracile, the graceful 
Staurastrum,* is another of the same order of plantsf as 
Closterium ; but your ‘ Sun,’ which is actually designated 
Actinophrys Sol (the radiating sun), from its resemblance 
to the source of light, is one of the lowest known forms of 
animal existence. 
“ One of the most remarkable objects in the field has, however, 
escaped your notice, and that is the insignificant slimy-looking’ 
mass a little to the left of Volvox.” 
“ What ! do you mean that which resembles the map of South 
America in miniature, and seems to be constantly changing its 
shape?” 
“ Precisely so ; and I am glad you have descended from the 
skies, and can, at length, find something on earth with which 
to compare it, even though it be a continent ! 
“ It does continually change its shape, and hence its name 
Amoeba, from a Greek word denoting that it alternates; but 
I must beg you to let it rest at present, and if, moreover, 
you will put aside the microscope, I will endeavour to describe, 
* This name is derived from two Greek words, signifying a “ cross” and a 
“ star.” 
t The Desmidiacea?. (See Ealf’s “ British Desmidiese.”) 
