24 POND LIFE 



THE BELL ANIMALCULES 



Some of the queerest little animals are members of this 

 family. The best known is the " Vorticella." Each little 

 creature consists of a cup, or bell, and a stalk, the latter able 

 to contract and expand in the manner of a coiled spring. 



The movement is aided by a muscle fibre, which passes 

 down the stalk. The mouth of the bell is surrounded by 

 cilia, and these producing aquatic currents, all sorts and 

 conditions of things are washed into the cavity. 



Similarly to most of the microscopic pond inhabitants, 

 vorticella are always busy. They uncoil, rising slowly until 

 their stalks are fully stretched ; for some few seconds the 

 cilia wave lustily, and then with a suddenness and surprising 

 rapidity they recoil. 



It would seem that the vorticella practically immediately 

 regret their action, for the very next moment they very 

 gradually unwind, the bell opens, and the cilia are very soon 

 most actively engaged. When they recoil the cilia are with- 

 drawn, and the bell takes the form of a ball. 



Vorticella multiplies by dividing longitudinally, and on 

 examining a colony several individuals are certain to be in 

 different stages of this function. When fission is complete 

 one of the individuals remains in the stalk, whilst the other 

 swims away and starts life " on its own." 



Vorticella also multiplies by conjugation. When this is 

 about to occur, one or more of the individual bells divides 

 rapidly into many small vorticella, and these, breaking away 

 from the stalk, swim to a mature individual. 



The smaller vorticella is absorbed by the larger. It is 

 interesting to know that if different parentage is prevented 

 (that is to say, the vorticella is forced to multiply with 

 relations), after a short while they become degenerated. 



It is really most surprising how rapidly colonies of vorticella 

 appear, become numerous, and disappear. 



One may find that the aquarium is well stocked with these 

 creatures in fact that weeds, broken sticks, and even snails 

 are covered with them, and within a very few days one may 

 search high and low, and not find a single colony. 



In the aquarium a colony of vorticella can be seen with the 

 naked eye, as white fur, on stems of weeds, &c. 



There are many kinds of bell animalcules some grow as 

 bunches on one stalk, others are in a tree-like colony with 



