AGE AND AREA 



A STUDY IN GEOGRAPHICAL DISTRIBUTION 

 AND ORIGIN OF SPECIES 



BY 



J. C. WILLIS 



M.A., Sc.D., Hon. ScD. (Harvard), F.R.S. 



European Correspondent, late Director, Botanic Gardens, 



Rio de Janeiro 



WITH CHAPTERS BY 



HUGO DE VRIES, F.M.R.S. 

 H. B. GUPPY, M.B., F.R.S. 

 Mrs E. M. REID, B.Sc, F.L.S. 

 JAMES SMALL, D.Sc, F.L.S. 



[These authors are not committed, by writing these chapters, 

 to the support of all the doctrines here advanced] 



CAMBRIDGE 



AT THE UNIVERSITY PRESS 



1922 



