176 HIDDEN BEAUTIES OF NATURE 



Several of such houses, if fastened together, would 

 pass through that minute opening. 



The Building Rotifer (Melicerta ringens) is found 

 in most of our English ponds. It makes its home on 

 plants, such as Valisneria spiralis, duckweed, or the 

 American weed, anacharis, etc. 



In an audience engaged in examining microscopic 

 beauties, if a vote were taken as to which was the 

 favourite object, most probably the building rotifer 

 would obtain the highest number of votes. The 

 exhibitor holds up a small glass tank in which he has 

 placed a few drops of pond water and a portion of 

 the above-named plants, and he says, pointing with a 

 needle, ' Do you see a tiny dark-brown speck on the 

 edge of that leaf or stalk ? ' as the case may be. The 

 person addressed examines the water, and after 

 looking closely, exclaims, 



' Yes ; I see the merest speck.' 



1 Quite right,' responds the microscopist ; * only that 

 is not " building rotifer," it is " rotifer's building." ' 



To see the builder we must place the tank under 

 the magnifier and throw a light through the water, 

 and remain perfectly quiet for a minute or two, as 

 building rotifer objects to much vibration. 



Then a wonderful sight appears. Rotifer unfolds a 

 disc fringed with cilia or tiny lashes. The motion 

 produced by these lashes has a peculiar effect on our 

 eyesight. We have a difficulty in getting away from 

 the impression that the whole disc is rotating, and 

 that a set of cogs is on the wheel margin. Clever 



