ANIMAL LIFE IN PONDS & STREAMS 



both bells, by the way, have the circlet of whips 

 round their upper edges. Soon after these additional 

 little whips are formed, the owner of them breaks 

 away from the stalk and swims about in the water 

 for a time, finally coming to rest on a suitable water 

 weed. Then the lower ring of whips has served its 

 purpose and in its place a long stalk grows; from 

 this time forward the new bell animalcule will never 

 move from the position it has chosen. This form of 

 increase, this simple splitting takes place over and 

 over again but by degrees the little animal appears 

 to become exhausted and the process slows down or 

 stops. 



The partially exhausted Vorticella may gain in- 

 creased vitality by fusion with another individual 

 and this process also we may have the luck to see 

 though it is less frequent than the simple splitting. 

 Sometimes a bell may be observed to divide, not 

 into halves, but into two unequal parts. The smaller 

 of these parts may divide again into from two to 

 eight parts, each one of which, having developed 

 a fringe of little whips, swims off on its own account. 

 These little barrel-shaped swimming forms, instead 

 of settling down and forming stalked bells, seek an 

 exhausted creature, fuse with it near the base of its 

 bell and finally become absorbed by it. The result 

 of this fusion is that the bell animalcule takes on 

 a new lease of life and once more begins to divide 

 actively. 



In our search for specimens for our microscope 

 we may come across a very common pond dweller, 



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