XI. 



DEGENERATION. 



By degeneration is meant the process by which a 

 living being changes for the worse. This implies a nar- 

 rowing range of powers and capabilities. The word is 

 opposed in meaning to change for the better, which we 

 call progress or development. 



Throughout the animal and vegetable kingdoms may- 

 be found instances of degenerate types. There are spe- 

 cies or groups of species which have de- 

 Decline in range i- j ■ i -^ r ^ ^ j 

 , ... clmed m complexity of structure and 

 of activities. ^ ■' 



range of activities as compared with 

 their ancestors. Degeneration of type appears when- 

 ever the range of competition is narrowed or incentive 

 to activity lessened. It takes place whenever a relaxa- 

 tion of the struggle for existence permits life on a lower 

 plane of activity or with less perfect adaptation to con- 

 ditions. Thus a land animal transferred to the sea has 

 its range of activity narrowed. There is competition 

 from fewer quarters, and a corresponding decline of 

 competitive structures takes place. 



The most striking cases of degeneration are those of 



quiescent animals, and parasitic animals and plants, as 



compared with their free-swimming self- 



. ^,^" dependent ancestors. Examples of de- 



animals. '^ . . ^ 



generate quiescent animals are the Tuni- 

 cates. These creatures, descended from fishlike ances- 

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