Double Adaptations 447 



bers of twisted individuals. In nature they are 

 able to maintain themselves during long cen- 

 turies, quite as well as normal species and va- 

 rieties. But they owe this quality entirely to 

 their dimorphous character. A twisted race of 

 teasels might consist of successive generations 

 of tall atavistic individuals, and produce year- 

 ly some twisted specimens, which might be de- 

 stroyed every time before ripening their seeds. 

 Reasoning from the evidence available, and 

 from analogous cases, the variety would, even 

 under such extreme circumstances, be able to 

 last as long as any other good variety or ele- 

 mentary species. And it seems to me that this 

 explanation makes clear how it is possible that 

 varieties, which are only potentially rich in 

 their peculiar monstrosity, are discovered from 

 time to time, when tested by experimental 

 methods. 



Granting these conclusions, monstrosities on 

 the one side, and dimorphous wild species on 

 the other, constitute the most striking examples 

 of the inheritance of latent characters. 



The bearing of the phenomena of dimorphism 

 upon the principles of evolution formulated by 

 Lamarck, and modified by his followers to con- 

 stitute Neo-Lamarckianism, remains to be con- 

 sidered. Lamarck assumed that the external 

 conditions directly affected the organisms in 



