46 A HALF-HOUR WITH THE 



found on a single stem, forming an exceedingly 

 beautiful object with the Microscope. The stalks 

 of these compound vorticellse are contracted toge- 

 ther, so that a large mass, expanding over the 

 whole field of the Microscope, suddenly disappears, 

 and, " like the baseless fabric of a vision, leaves not 

 a wreck behind." A little patience, however, and 

 the fearful creatures will once more be seen to 

 expand themselves in all their beauty. The mouth 

 of their little cup is surrounded by cilia, which 

 are in constant movement ; and when examined 

 minutely, they will be found to possess two aper- 

 tures, through one of which currents of water 

 pass into the body, and from the other pass out. 

 Not unfrequently the cup breaks off its stalk. It 

 then contracts its mouth, and proceeds to roll about 

 free in the water. Many other curious changes in 

 form and condition have been observed in these 

 wonderful bell-shaped animalcules. 



If, now, we go to a very dirty pond indeed, into 

 which cesspools are emptied, and dead dogs and 

 cats are thrown, we shall find abundant employ- 

 ment for our Microscope in the beautiful forms of 

 animalcules which are placed by the Creator in 

 these positions to clear away the dirt and filth, and 

 prevent its destroying the life of higher animals. 

 In such waters, amongst a host of minor forms, we 

 are almost sure to meet with the magnificent Para- 

 mcecium Amelia (Fig. 34, PI. 2). He moves about 

 the water a king amongst the smaller prey on 

 whom he feeds without ceasing. He is of an. 

 oblong form, covered all over with cilia, and very 

 rapid and active in his movements, as able to dart 

 forwards as backwards, and turning round with the 

 greatest facility. In his inside several spots are 

 observed. If a little indigo or carmine is intro- 

 duced into the water in which he lives, these spots 



