164 DROPS OF WATER. 



the water, the animal will adhere to it by its tail, 

 and display its wheels. I kept them in the same 

 mug for ten years. 33 This transparent creature 

 is fusiform, or spindle-shaped, tapering gra- 

 dually to the foot when expanded, but when 

 "contracted it is thick, and the head and tail dis- 

 appear within the body ; the joints are not visible 

 when the creature is expanded, but when con- 

 tracting, their curious conformation is seen, and 

 the method of sliding one within the other clearly 

 observable. The foot, or tail, has six processes, 

 placed two and two at the joints. The upper ex- 

 tremity of the body has a pair of wheels, distinct 

 from each other, and of very wonderful construc- 

 tion ; when the wreaths of cilia which form them 

 are in full motion, they produce strong currents 



