AMCEBA /IND PARAMCECIUM 33 



nucleus, a very complex little structure of great impor- 

 tance in the make-up of Amceba. 



Note that A moeba has no mouth or alimentary canal; 

 no nostrils or lungs, no heart or blood-vessels, no mus- 

 cles, no glands. It is an animal body not made up of 

 distinct organs and diverse tissues. Its whole body is a 

 simple minute speck of protoplasm, a single animal cell. 

 But it takes in food, it moves, it excretes waste matter 

 from the body, is sensitive to the touch of surrounding 

 objects, and, as we may be able to see, it can reproduce 

 itself, i.e., produce new Amcebce. Amoeba is the simplest 

 living animal. 



It is only rarely that we can find an Amoeba actually 

 reproducing. The process, in its gross features, is very 

 simple. First the Amoeba draws in all of its pseudopodia 

 and remains dormant for a time. Next, certain changes 

 take place in the nucleus, which divides into equal por- 

 tions, one part withdrawing to one end of the protoplasmic 

 body, the other to the opposite end. Soon the body pro- 

 toplasm itself begins to divide into two parts, each part 

 collecting about its own half of the nucleus. Finally the 

 two halves pull entirely away from each other and form 

 two new Amoebce^ each like the original, but only half as 

 large. This is the simplest kind of reproduction found 

 among animals. 



Amoeba continue to live and multiply as long as the 

 conditions surrounding them are favorable. But when 

 the pond dries up the Amcebcz in it would be exterminated 

 were it not for a careful provision of nature. When the 

 pond begins to dry up each Amoeba contracts its pseudo- 

 podia and the protoplasm secretes a horny capsule about 

 itself. It is now protected from dry weather and can be 

 blown by the winds from place to place until the rains 

 begin, when it expands, throws off the capsule and com- 

 mences active life again in some new pond. 



