144 ORIGIN OF SPECIES 



its summit, so we occasionally see an animal like the Ornitho- 

 rhynchus or Lepidosiren. which in some small degree con- 

 nects by its affinities two large branches of life, and which 

 has apparently been saved from fatal competition by having 

 inhabited a protected station. As buds give rise by growth 

 to fresh buds, and these, if vigorous, branch out and overtop 

 on all sides many a feebler branch, so by generation I believe 

 it has been with the great Tree of Life, which fills with 

 its dead and broken branches the crust of the earth, and 

 covers the surface with its ever-branching and beautiful 

 ramifications. 



