CHAPTER XIII 



MULTIPLICATION AND DEVELOPMENT. MUL- 

 TIPLICATION OF ONE-CELLED ANIMALS 



Multiplication. We know that any living animal has 

 parents; that is, has been produced by other animals 

 which may still be living or be now dead or, as with 

 Amoeba, may have changed, by division, into new indi- 

 viduals. Individuals die, but before death, they produce 

 other individuals like themselves. If they did not, their 

 kind or species would die with them. This production 

 of new animals constantly going on is called the repro- 

 duction or multiplication of animals. The process is 

 well called multiplication, because each female animal 

 normally produces more than one new individual. She 

 may produce only one at a time, one a year, as many of 

 the sea-birds do or as the elephant does, but she lives 

 many years. Or she may produce hundreds, or thou- 

 sands, or even millions of young in a very short time. 

 A lobster lays 10,000 eggs at a time. Nearly nine 

 millions of eggs have been taken from the body of a 

 thirty-pound female codfish. As a matter of fact but 

 very, very few of these eggs produce new animals which 

 reach maturity. From the 10,000 eggs produced by the 

 lobster each year an average of but two new mature 

 lobsters is produced. There is always a struggle for food 

 and for place going on among animals, for many more 

 are produced than there are food and room for, and so of 

 all the new or young animals which are born the great 



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