18 DROPS OF WATER. 



hundred millions of the smallest animalcules. 

 What, then, can be the population of a lake, or 

 of the ocean ! 



I have watched specimens of the genera Flos- 

 eularia, Forticella, and Stentor, for hours at a 

 time, and they have never ceased to feed on mi- 

 nute portions of animal and vegetable substances, 

 brought to them by the current they are enabled 

 to make in the water ; others eagerly pursue their 

 prey, or feed on the decaying vegetable matter 

 floating about : indeed, the appetite of these little 

 creatures seems insatiable. Many genera have 

 a strong chewing apparatus, like a mouth armed 

 with teeth. All seem employed in the same 

 way, though using different methods :--much 

 decaying matter must thus be taken away by 



