48 A HALF- HOUR WITH THE 



whilst a projecting organ, whose function is imper- 

 fectly understood, is seen directly below them. The 

 tail is finished off with a pair of little nippers, by 

 which the creature has the power of attaching itself 

 to objects. When moving, its whole body is ex- 

 tended, but it has the power of drawing itself up 

 like a telescope in its case, and appearing almost 

 round. 



The wheel- animalcules abound in our ponds and 

 rivers, and sometimes occur in great numbers in 

 the aquarium. They are very various in their 

 forms, and some of them possess great beauty. 

 Some of them are fixed, forming a little case or 

 tube on the outside of their bodies^ in which they 

 dwell. 



