118 DROPS OF WATER. 



where a wreath of large cilia are in constant vi- 

 bration, enabling them to draw within the body 

 the food they require : this consists of Monads, 

 and various little creatures ; and as most of the 

 species are transparent, the digestive cells may be 

 plainly seen filling gradually with these unfortu- 

 nate little beings. Stentors increase by self-divi- 

 sion longitudinally, and also by eggs. S. Mul- 

 len is white, transparent, and large. S. Roeselii 

 (Drop III. fig. 1) is equal in size, but rather 

 more yellow in colour. They both contract, when 

 swimming, into the form of an oblong ball, but 

 when fixed, stretch out considerably ; when two 

 or three are attached near each other, and 

 all have their mouth-cilia at work, the current 

 they form in the water is quite extraordinary, 



