BOOK II 



THE PATH OF DEGENERATIVE 

 EVOLUTION 



PART I 



THE SUPPOSED LAW THAT DEGENERATION RETRACES 

 THE STEPS OF PROGRESS 



IT is a common opinion, supported partly by the 

 etymology of the word, that retrogression is a tracing 

 backwards of progression. 



" In the degeneration of organizations fallen out 

 of use,''' M. A. Larneere has said, " it is to be ob- 

 served that the structures formed most recently 

 and most specialized are the first to disappear, and 

 that the most fundamental characters are those 

 which persist longest : that in fact degenerative 

 evolution retraces the steps made by progressive 

 evolution. Peculiarities recently acquired, if they 

 become disused, rapidly disappear, while dispositions 

 of a more ancient kind have a persistence almost 

 exactly proportioned to their age. 1 



This supposed biological law of retracement has 



1 A. Lameere, Esquisse de la Zoologie, Bruxelles, Rosez, p. 184. 



175 



