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- 
clined in complexity of structure and 
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- 
generate quiescent animals are the Tuni- 
cates. These creatures, descended from fishlike ances- 
277 
Decline in range 
of activities. 
Quiescent 
animals. 
