LARVAE, ETC. 179 



shaped somewhat like a vase, and smaller than 

 the other species. 



Many other creatures of small size, besides 

 Infusoria, will of course be met with in water, 

 but they will soon be recognized as belonging to 

 other classes of the animal kingdom. Several 

 long, worm-like creatures, are the larvae of the 

 gnat and midge, or perhaps those of the dragon- 

 fly or Tipula. There are several species, also, of 

 Vibrio, which will soon be distinguished if the 

 one found in sour paste is known. Then there is 

 a pretty and very lively little creature frequently 

 seen where duckweed abounds, the Lyncivx splia- 

 ricus. It is enclosed in a round, transparent 

 shell, the only projection being a beak, and the 



