THE RADIOLARIA 95 



purity, the well-known rook-orystal. This flint 

 matter (and sometimes a similar substance) is 

 then exuded again by the radiolarian — no one 

 knows quite how — from its gelatinous body, and 

 built into so beautiful a form that even a child 

 will clap its hands and cry, " How lovely ! " when 

 it sees it through the microscope. We may put 

 it that the radiolarian forms a coat of mail for 

 itself from this siliceous matter : we may at 

 the same time call it a float or buoy. The hard 

 flinty structure serves to keep it balanced when 

 it is swimming, just as when a loose piece of 

 jelly attaches itself to a cork disk. Thus a round 

 trellis-work shell is formed about the animal, 

 and through the apertures it thrusts gelatinous 

 processes that act as oars, and can be put forth 

 or drawn in at will ; outside this shell, again, may 

 be all sorts of structures, such as zigzag shaped 

 rods, radiating stars, bundles of streamers, and 

 so on. It is a most wonderful sight. It is as 

 if each class of these beings had its private taste, 

 and, in virtue of a kind of tradition, built a dif- 

 ferent type of flinty skeleton from all the others. 

 Here begins the peculiar artistic wizardry of these 

 tiny and lowly creatures, that lifts them at once 

 high up in the scale of animated natural objects 

 with a great display of beauty. We find every 

 possible variation of ornament within the limits 

 of the particular type : an infinite number of 

 crystalline and superb variations on the theme 

 of trellis-work, stars, radiating shields, crosses, 

 and halberds. They give an impression at once 



