266 PRACTICAL LESSONS IN SCIENCE. 



The Eotifera are worms with a ciliated apparatus at the ante- 

 rior end of the body which vibrates so rapidly as to produce the 

 impression of a rotating wheel; hence the name of wheel-animal- 

 cules. Some are free-swimming and some are fixed. In the free 

 forms the cilia are the organs of locomotion, and in all cases they 

 create currents in the water by which particles of food, as small 

 infusoria, algae and diatoms are brought within their reach. In 

 external appearance they are much like some infusoria, but they 

 are evidently of a higher order. The rotifer can be dried, then 

 brought to life by a little water, for many times in succession 

 without apparent injury. 



