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 dined jn 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- 

 Quiescent dependent ancestors. Examples of de- 

 animals. . , , _, 



generate quiescent animals are the Tum- 



cates. These creatures, descended from fishlike ances- 



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